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Sample records for acid soils due

  1. Assessing biogeographic patterns in the changes in soil invertebrate biodiversity due to acidic deposition

    SciTech Connect

    Sugg, P.M.; Kuperman, R.G.; Loucks, O.L. |

    1995-09-01

    We are studying the response of soil faunal communities to a gradient in acidic deposition across midwestern hardwood forests. We have documented a pattern of population decrease and species loss for soil invertebrates along the acidification gradient. We now ask the following question: When confronted with apparent diversity changes along a region-wide pollution gradient, how can one assess the possibility of natural biogeographic gradients accounting for the pattern? As a first approximation, we use published range maps from taxonomic monographs to determine the percent of the regional fauna with ranges encompassing each site. For staphylinid beetles, range data show no sign of a biogeographic gradient. Yet for soil staphylinids, a large decrease is seen in alpha diversity (as species richness) from low to high acid dose sites (from 20 species to 8). Staphylinid species turnover is greatest in the transition from low to intermediate dose sites.

  2. Pediatric Sialadenosis Due to Valproic Acid.

    PubMed

    Derin, Hatice; Derin, Serhan; Oltulu, Pembe; Özbek, Orhan; Çaksen, Hüseyin

    2016-12-23

    Sialadenosis is a rare entity characterized by bilateral diffuse, painless swelling of the parotid glands. Its etiology is not clear; however, it may occur due to adverse effects of some drugs. To our knowledge, sialadenosis due to valproic acid has not been reported in the literature up to date in any child. In this article, the authors presented a child who developed sialadenosis due to valproic acid, and improved after stopping use of the drug.

  3. Designer, acidic biochar influences calcareous soil characteristics.

    PubMed

    Ippolito, J A; Ducey, T F; Cantrell, K B; Novak, J M; Lentz, R D

    2016-01-01

    In a proof-of-concept study, an acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 °C) and steam activation (800 °C) to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0%, 1%, 2%, and 10% (by wt.) and soils were destructively sampled at 1, 2, 3, 4, 5, and 6 month intervals. Soil was analyzed for gravimetric water content, pH, NO3-N, plant-available Fe, Zn, Mn, Cu, and P, organic C, CO2 respiration, and microbial enumeration via extractable DNA and 16S rRNA gene copies. Gravimetric soil water content increased with biochar application regardless of rate, as compared to the control. Soil pH decreased between 0.2 and 0.4 units, while plant-available Zn, Mn, and P increased with increasing biochar application rate. Micronutrient availability decreased over time likely due to insoluble mineral species precipitation. Increasing biochar application raised the soil organic C content and remained elevated over time. Increasing biochar application rate also increased respired CO2, yet the CO2 released decreased over time. Soil NO3-N concentrations significantly decreased with increasing biochar application rate likely due to microbial immobilization or denitrification. Depending on application rate, biochar produced a 1.4 to 2.1-fold increase in soil DNA extracted and 1.4- to 2.4-fold increase in 16S rRNA gene abundance over control soils, suggesting microbial stimulation and a subsequent burst of activity upon biochar addition. Our results showed that there is promise in designing a biochar to improve the quality and water relations of eroded calcareous soils.

  4. Uncertainty in soil carbon accounting due to unrecognized soil erosion.

    PubMed

    Sanderman, Jonathan; Chappell, Adrian

    2013-01-01

    The movement of soil organic carbon (SOC) during erosion and deposition events represents a major perturbation to the terrestrial carbon cycle. Despite the recognized impact soil redistribution can have on the carbon cycle, few major carbon accounting models currently allow for soil mass flux. Here, we modified a commonly used SOC model to include a soil redistribution term and then applied it to scenarios which explore the implications of unrecognized erosion and deposition for SOC accounting. We show that models that assume a static landscape may be calibrated incorrectly as erosion of SOC is hidden within the decay constants. This implicit inclusion of erosion then limits the predictive capacity of these models when applied to sites with different soil redistribution histories. Decay constants were found to be 15-50% slower when an erosion rate of 15 t soil ha(-1)  yr(-1) was explicitly included in the SOC model calibration. Static models cannot account for SOC change resulting from agricultural management practices focused on reducing erosion rates. Without accounting for soil redistribution, a soil sampling scheme which uses a fixed depth to support model development can create large errors in actual and relative changes in SOC stocks. When modest levels of erosion were ignored, the combined uncertainty in carbon sequestration rates was 0.3-1.0 t CO2  ha(-1)  yr(-1) . This range is similar to expected sequestration rates for many management options aimed at increasing SOC levels. It is evident from these analyses that explicit recognition of soil redistribution is critical to the success of a carbon monitoring or trading scheme which seeks to credit agricultural activities.

  5. Designer, acidic biochar influences calcareous soil characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 degrees celsius) and steam activation to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0, 1, 2, and 10 percent (by weight) to an eroded Portneuf soil (coarse-silty,...

  6. Influences of soil acidity on Streptomyces populations inhabiting forest soils.

    PubMed Central

    Hagedorn, C

    1976-01-01

    The Streptomyces populations inhabiting five acidic forest soils were examined. It was found that lowering the pH of a medium selective for streptomycetes (starch-casein agar) to the pH of the particular soil horizon being plated influenced both the total numbers and types of streptomycetes that were isolated from the soils examined in this study. On the acidified medium both the numbers of streptomycetes and the percentage of total bacteria on the plates represented by streptomycetes increased (as compared with the same medium with a pH of 7.2). These differences were greatest on the isolations from the most acid soils. The largest concentrations of streptomycetes were found in the surface horizon (0 to 15 cm) and the litter layer immediately over the surface mineral horizon. Acidity tolerance tests demonstrated that random samplings of isolates contained acidophilic, neutrophilic, and acidoduric strains, with the largest numbers of acidophiles being found on the acidified media from the most acid soils. There were no differences between overall utilization of selected carbohydrates among the isolates taken from either the neutral or acidic media, although a larger proportion of the acid media isolates produced acid from the carbohydrates. Evidence is presented which indicates that different types of streptomycetes were isolated on the acid media, and possible reasons for the presence of these acid-tolerant populations are discussed. PMID:10835

  7. Soil temperature regime and vulnerability due to extreme soil temperatures in Croatia

    NASA Astrophysics Data System (ADS)

    Sviličić, Petra; Vučetić, Višnja; Filić, Suzana; Smolić, Ante

    2016-10-01

    Soil temperature is an important factor within the climate system. Changes of trends in soil temperature and analysis of vulnerability due to heat stress can provide useful information on climate change. In this paper, the soil temperature regime was analyzed on seasonal and annual scales at depths of 2, 5, 10, 20, 30, and 50 cm at 26 sites in Croatia. Trends of maximal, mean, and minimal soil temperatures were analyzed in the periods 1961-2010 and 1981-2010. Duration of extreme soil temperatures and vulnerability due to high or low soil temperatures in the recent standard period 1981-2010 was compared with the reference climate period 1961-1990. The results show a general warming in all seasons and depths for maximal and mean temperatures in both observed periods, while only at some locations for minimal soil temperature. Warming is more pronounced in the eastern and coastal parts of Croatia in the surface layers, especially in the spring and summer season in the second period. Significant trends of maximal, minimal, and mean soil temperature in both observed periods range from 2.3 to 6.6 °C/decade, from -1.0 to 1.3 °C/decade, and from 0.1 to 2.5 °C/decade, respectively. The highest vulnerability due to heat stress at 35 °C is noted in the upper soil layers of the coastal area in both observed periods. The mountainous and northwestern parts of Croatia at surface soil layers are the most vulnerable due to low soil temperature below 0 °C. Vulnerability due to high or low soil temperature decreases with depth.

  8. Acid soils of western Serbia and their further acidification

    NASA Astrophysics Data System (ADS)

    Mrvic, Vesna

    2010-05-01

    Acid soils cause many unfavorable soil characteristics from the plant nutrition point of view. Because of increased soil acidity the violation of buffering soil properties due to leaching of Ca and Mg ions is taking place that also can cause soil physical degradation via peptization of colloids. Together with increasing of soil acidity the content of mobile Al increases that can be toxic for plants. Easily available nutritive elements transforms into hardly avaialble froms. The process of deactivation is especially expressed for phosphorous that under such conditions forms non-soluble compounds with sesqui-oxides. From the other hand the higher solubility of some microelements (Zn and B) can cause their accelerated leaching from root zone and therefore, result in their deficiency for plant nutrition. Dangerous and toxic matters transforms into easly-available forms for plants, especially, Cd and Ni under the lower soil pH. The studied soil occupies 36675 hectare in the municipality of Krupan in Serbia, and are characterized with very unfavorable chemical properties: 26% of the territory belongs to the cathegory of very acidic, and 44 % belongs to the cathegory of acidic. The results showed that the soil of the territory of Krupan is limited for agricultural land use due to their high acidity. Beside the statement of negative soil properties determined by acidity, there is a necessity for determination of soil sensitivity for acidification processes toward soil protection from ecological aspect and its prevention from further acidification. Based on such data and categorization of soils it is possible to undertake proper measures for soil protection and melioration of the most endangered soil cover, where the economic aspect of these measures is very important. One of the methods of soil classification based on sensitivity for acidification classification the determination of soil categories is based on the values of soil CEC and pH in water. By combination of these

  9. Mechanisms for the retention of inorganic N in acidic forest soils of southern China

    PubMed Central

    Zhang, Jin-bo; Cai, Zu-cong; Zhu, Tong-bin; Yang, Wen-yan; Müller, Christoph

    2013-01-01

    The mechanisms underlying the retention of inorganic N in acidic forest soils in southern China are not well understood. Here, we simultaneously quantified the gross N transformation rates of various subtropical acidic forest soils located in southern China (southern soil) and those of temperate forest soils located in northern China (northern soil). We found that acidic southern soils had significantly higher gross rates of N mineralization and significantly higher turnover rates but a much greater capacity for retaining inorganic N than northern soils. The rates of autotrophic nitrification and NH3 volatilization in acidic southern soils were significantly lower due to low soil pH. Meanwhile, the relatively higher rates of NO3− immobilization into organic N in southern soils can counteract the effects of leaching, runoff, and denitrification. Taken together, these processes are responsible for the N enrichment of the humid subtropical forest soils in southern China. PMID:23907561

  10. Acid rain on acid soil: a new perspective

    SciTech Connect

    Krug, E.C.; Frink, C.R.

    1983-08-05

    Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and Northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.

  11. Acid rain on acid soil: a new perspective

    SciTech Connect

    Krug, E.C.; Frink, C.R.

    1983-08-05

    Acid rain is widely believed to be responsible for acidifying soil and water in areas of North America and northern Europe. However, factors commonly considered to make landscapes susceptible to acidification by acid rain are the same factors long known to strongly acidify soils through the natural processes of soil formation. Recovery from extreme and widespread careless land use has also occurred in regions undergoing acidification. There is evidence that acidification by acid rain is superimposed on long-term acidification induced by changes in land use and consequent vegetative succession. Thus, the interactions of acid rain, acid soil, and vegetation need to be carefully examined on a watershed basis in assessing benefits expected from proposed reductions in emissions of oxides of sulfur and nitrogen.

  12. Acid soil indicators in forest soils of the Cherry River Watershed, West Virginia.

    PubMed

    Farr, C; Skousen, J; Edwards, P; Connolly, S; Sencindiver, J

    2009-11-01

    Declining forest health has been observed during the past several decades in several areas of the eastern USA, and some of this decline is attributed to acid deposition. Decreases in soil pH and increases in soil acidity are indicators of potential impacts on tree growth due to acid inputs and Al toxicity. The Cherry River watershed, which lies within the Monongahela National Forest in West Virginia, has some of the highest rates of acid deposition in Appalachia. East and West areas within the watershed, which showed differences in precipitation, stream chemistry, and vegetation composition, were compared to evaluate soil acidity conditions and to assess their degree of risk on tree growth. Thirty-one soil pits in the West area and 36 pits in the East area were dug and described, and soil samples from each horizon were analyzed for chemical parameters. In A horizons, East area soils averaged 3.7 pH with 9.4 cmol(c) kg(-1) of acidity compared to pH 4.0 and 6.2 cmol(c) kg(-1) of acidity in West area soils. Extractable cations (Ca, Mg, and Al) were significantly higher in the A, transition, and upper B horizons of East versus West soils. However, even with differences in cation concentrations, Ca/Al molar ratios were similar for East and West soils. For both sites using the Ca/Al ratio, a 50% risk of impaired tree growth was found for A horizons, while a 75% risk was found for deeper horizons. Low concentrations of base cations and high extractable Al in these soils translate into a high degree of risk for forest regeneration and tree growth after conventional tree harvesting.

  13. Changes in soil CO2 efflux of organic calcaric soils due to disturbance by wind

    NASA Astrophysics Data System (ADS)

    Mayer, M.; Katzensteiner, K.

    2012-04-01

    Disturbances such as windthrow or insect infestations are supposed to have a significant influence on the soil carbon balance of affected forests. Increasing soil temperatures and changes in the soil moisture regime, caused by the removed tree layer, are expected to change soil CO2 efflux, also known as soil respiration. Beside an anticipated stimulation of the carbon mineralization, the main part of root allocated CO2 is offset due to the blown down trees. On mountain forest sites of the Northern Limestone Alps, where highly active organic soils above calcareous parent material are characteristic (Folic Histosols and Rendzic Leptosols), an increase of the mineralization rate of carbon may contribute to enormous humus losses. Serious site degradation can be the consequence, especially on south exposed slopes where extreme climatic conditions occur. The present study tries to give insights to disturbance induced changes in temporal and spatial behaviour of soil respiration for a montane mountain forest located in the Northern Limestone Alps of Upper Austria. Soil respiration, soil temperature and volumetric water content were measured on two windthrow areas (blow down dates were 2007 and 2009 respectively) as well as in an adjacent mature mixed forest during the vegetation periods of 2010 and 2011. Soil respiration in both years was mainly driven by soil temperature, which explained up to 90 % of the concerning temporal variation. Volumetric water content had a significant influence as additional temporal driver. After removing the temperature trend, significant differences in basal soil respiration rates were found for the disturbance area and the forest stand. Inter seasonal declines in soil respiration were ascertained for the mature stand as well as for the recent windthrow. Particular decreases are related to drought stress in summer 2011 and a proceeded decomposition of labile soil carbon components at the windthrow site. An interaction between soil type and

  14. Severe Hyponatremia Due to Valproic Acid Toxicity.

    PubMed

    Gupta, Ena; Kunjal, Ryan; Cury, James D

    2015-09-01

    Hyponatremia is a very commonly encountered clinical entity with potentially dangerous effects and for which many precipitating factors have been identified. We present a case of valproic acid (VPA) overdose causing profound hyponatremia, with one of the lowest serum sodium levels ever documented in literature. A 54-year-old woman with hypothyroidism, hypertension and bipolar disorder presented with somnolence after intentionally ingesting 7,500 mg VPA. She was drowsy but easily arousable with no hemodynamic compromise and an unremarkable physical exam. There was no clinical suspicion for organic neurological or pulmonary disease, adrenal insufficiency or volume depletion. She was found to have a serum sodium of 99 mEq/L, low plasma osmolality (211 mOsm/kg H2O), and high urine osmolality (115 mOsm/kg H2O). Her urine sodium was 18 mEq/L. She was euthyroid (TSH: 3.06 mIU/L) and compliant with thyroxine replacement. She was admitted to the intensive care unit for close monitoring and VPA was withheld. Over 36 hours her VPA level fell from 59.3 mg/L to 22.8 mg/L, serum sodium steadily rose to 125 mEq/L and there was concomitant improvement in her mental status. At 72 hours, she was transferred for an inpatient psychiatric evaluation and her sodium level was 135 mEq/L. She luckily did not experience any seizures or decline in neurological function. The clinical presentation in this patient is consistent with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) leading to a dramatic fall in sodium to a level of 99 mEq/L. Chronic VPA use has been associated with SIADH and chronic hyponatremia. Review of records in this patient from 1 year prior revealed that her last measured sodium level was 127 mEq/L. It is therefore most likely that our case is one of acute on chronic hyponatremia provoked by VPA overdose in the setting of chronic VPA use. Whilst our patient's course was relatively benign, this case illustrates a rare consequence of VPA toxicity, which

  15. Effect of soil acidity, soil strength and macropores on root growth and morphology of perennial grass species differing in acid-soil resistance.

    PubMed

    Haling, Rebecca E; Simpson, Richard J; Culvenor, Richard A; Lambers, Hans; Richardson, Alan E

    2011-03-01

    It is unclear whether roots of acid-soil resistant plants have significant advantages, compared with acid-soil sensitive genotypes, when growing in high-strength, acid soils or in acid soils where macropores may allow the effects of soil acidity and strength to be avoided. The responses of root growth and morphology to soil acidity, soil strength and macropores by seedlings of five perennial grass genotypes differing in acid-soil resistance were determined, and the interaction of soil acidity and strength for growth and morphology of roots was investigated. Soil acidity and strength altered root length and architecture, root hair development, and deformed the root tip, especially in acid-soil sensitive genotypes. Root length was restricted to some extent by soil acidity in all genotypes, but the adverse impact of soil acidity on root growth by acid-soil resistant genotypes was greater at high levels of soil strength. Roots reacted to soil acidity when growing in macropores, but elongation through high-strength soil was improved. Soil strength can confound the effect of acidity on root growth, with the sensitivity of acid-resistant genotypes being greater in high-strength soils. This highlights the need to select for genotypes that resist both acidity and high soil strength.

  16. Soils affected by heavy metals due to old mining on perudic conditions

    NASA Astrophysics Data System (ADS)

    Garrigo, Jordi; Elustondo, David; Laheras, Ester; Oiarzabal, Maite; Jaume, Bech

    2010-05-01

    The aim of this work is to assess the actual status of the soils of a natural environment surrounding an abandoned mine (exploited since the Roman Age) where Pb, Zn, Fe and Cu were obtained. The study has been carried out in the Aitzondo valley (Guipuzkoa, North of Iberian Peninsula), which cross the exploited mountainous area with middle temperatures and perudic soil moisture regime Soils in the valley are polygenic, acids, very washed and sometimes show redoximorphic features and have undergone a great mobilization of trace metals due to these physical-chemical characteristics that enhance the heavy metals solubility and mobility. The analysis of soil surface samples shows a punctual and intense pollution at Meazuri area (where the mine is located) and another more dispersal and wide pollution due to the parent material (Palaeozoic shales). The main soil type of the area has been characterized by means of the performance of a soil and six surface samples have been collected along an altitudinal transect, which goes down from 460 to 75 meters. Both profile and surface samples have been analysed for suitable parameters due to their repercussion in mobility and fixation of some heavy metals (organic matter, clay content…). Total (Na, K, Mg, Ca, Al, Fe, Mn, Ti, Cd, Cr) and extractable fraction (using NH4Ac-EDTA pH=4.65, as extracting agent, have been analysed. Trace elements Cd, Cr, Cu, Ni, Pb and Zn have been measured. On summary, the soils studied are characterized by high levels of trace metals inherited from the parent material whose composition shows a great metallic richness. Hence, values of trace metals are very high even in remote areas where there has not been anthropic influence. Besides, the physical-chemical properties (acidity, base saturation, organic matter) have enhanced the mobility of trace metals. The anthropogenic activity (mining activity) has caused an increase in values of several metals, reaching, in some cases, concentrations above the

  17. HONO (nitrous acid) emissions from acidic northern soils

    NASA Astrophysics Data System (ADS)

    Maljanen, Marja; Yli-Pirilä, Pasi; Joutsensaari, Jorma; Martikainen, Pertti J.

    2015-04-01

    The photolysis of HONO (nitrous acid) is an important source of OH radical, the key oxidizing agent in the atmosphere, contributing also to removal of atmospheric methane (CH4), the second most important greenhouse gas after carbon dioxide (CO2). The emissions of HONO from soils have been recently reported in few studies. Soil HONO emissions are regarded as missing sources of HONO when considering the chemical reactions in the atmosphere. The soil-derived HONO has been connected to soil nitrite (NO2-) and also directly to the activity of ammonia oxidizing bacteria, which has been studied with one pure culture. Our hypothesis was that boreal acidic soils with high nitrification activity could be also sources of HONO and the emissions of HONO are connected with nitrification. We selected a range of dominant northern acidic soils and showed in microcosm experiments that soils which have the highest nitrous oxide (N2O) and nitric oxide (NO) emissions (drained peatlands) also have the highest HONO production rates. The emissions of HONO are thus linked to nitrogen cycle and also NO and N2O emissions. Natural peatlands and boreal coniferous forests on mineral soils had the lowest HONO emissions. It is known that in natural peatlands with high water table and in boreal coniferous forest soils, low nitrification activity (microbial production of nitrite and nitrate) limits their N2O production. Low availability of nitrite in these soils is the likely reason also for their low HONO production rates. We also studied the origin of HONO in one peat soil with acetylene and other nitrification inhibitors and we found that HONO production is not closely connected to ammonium oxidation (nitrification). Acetylene blocked NO emissions but did not affect HONO or N2O emissions, thus there is another source behind HONO emission from these soils than ammonium oxidation. It is still an open question if this process is microbial or chemical origin.

  18. Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

    NASA Technical Reports Server (NTRS)

    Amashukeli, Xenia; Pelletier, Christine C.; Kirby, James P.; Grunthaner, Frank J.

    2007-01-01

    Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor- phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert ( Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids ( alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1 - 70 parts- per- billion. Subcritical water extraction efficiency was examined over the temperature range of 30 - 325 degrees C, at pressures of 17.2 or 20.0 MPa, and for water- sample contact equilibration times of 0 - 30 min. None of the amino acids were extracted in detectable amounts at 30 degrees C ( at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 degrees C and 250 degrees C ( at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 degrees C ( at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 degrees C, 17.2 MPa, and a water- sample contact equilibration time of 10 min.

  19. Survival of Rhizobium in Acid Soils

    PubMed Central

    Lowendorf, Henry S.; Baya, Ana Maria; Alexander, Martin

    1981-01-01

    A Rhizobium strain nodulating cowpeas did not decline in abundance after it was added to sterile soils at pH 6.9 and 4.4, and the numbers fell slowly in nonsterile soils at pH 5.5 and 4.1. A strain of R. phaseoli grew when added to sterile soils at pH 6.7 and 6.9; it maintained large, stable populations in soils of pH 4.4, 5.5, and 6.0, but the numbers fell markedly and then reached a stable population size in sterile soils at pH 4.3 and 4.4. The abundance of R. phaseoli added to nonsterile soils with pH values of 4.3 to 6.7 decreased similarly with time regardless of soil acidity, and the final numbers were less than in the comparable sterile soils. The minimum pH values for the growth of strains of R. meliloti in liquid media ranged from 5.3 to 5.9. Two R. meliloti strains, which differed in acid tolerance for growth in culture, did not differ in numbers or decline when added to sterile soils at pH 4.8, 5.2, and 6.3. The population size of these two strains was reduced after they were introduced into nonsterile soils at pH 4.8, 5.4, and 6.4, and the number of survivors was related to the soil pH. The R. meliloti strain that was more acid sensitive in culture declined more readily in sterile soil at pH 4.6 than did the less sensitive strain, and only the former strain was eliminated from nonsterile soil at pH 4.8; however, the less sensitive strain also survived better in limed soil. The cell density of the two R. meliloti strains was increased in pH 6.4 soil in the presence of growing alfalfa. The decline and elimination of the tolerant, but not the sensitive, strain was delayed in soil at pH 4.6 by roots of growing alfalfa. PMID:16345909

  20. Acid soil and acid rain, 2nd edition

    SciTech Connect

    Kennedy, I.R.

    1992-01-01

    This book examines the basic chemical processes involved in acidification in order to better assess their long-term effects on the status of soils, the health of plants and other living species that depend on them. It also discusses acidity, pH and protons their significance in bioenergetics and the consequent role of autotrophic organisms in acidifying ecosystems. This edition incorporates and integrates recent findings that render more explanations of the causes of the environmental impacts of acidity, especially in forests and lakes. Also explores current research into acid rain and soil in order to devise appropriate measures for their amelioration.

  1. The abiotic degradation of soil organic matter to oxalic acid

    NASA Astrophysics Data System (ADS)

    Studenroth, Sabine; Huber, Stefan; Schöler, H. F.

    2010-05-01

    The abiotic degradation of soil organic matter to volatile organic compounds was studied intensely over the last years (Keppler et al., 2000; Huber et al., 2009). It was shown that soil organic matter is oxidised due to the presence of iron (III), hydrogen peroxide and chloride and thereby produces diverse alkyl halides, which are emitted into the atmosphere. The formation of polar halogenated compounds like chlorinated acetic acids which are relevant toxic environmental substances was also found in soils and sediments (Kilian et al., 2002). The investigation of the formation of other polar halogenated and non-halogenated compounds like diverse mono- and dicarboxylic acids is going to attain more and more importance. Due to its high acidity oxalic acid might have impacts on the environment e.g., nutrient leaching, plant diseases and negative influence on microbial growth. In this study, the abiotic formation of oxalic acid in soil is examined. For a better understanding of natural degradation processes mechanistic studies were conducted using the model compound catechol as representative for structural elements of the humic substances and its reaction with iron (III) and hydrogen peroxide. Iron is one of the most abundant elements on earth and hydrogen peroxide is produced by bacteria or through incomplete reduction of oxygen. To find suitable parameters for an optimal reaction and a qualitative and quantitative analysis method the following reaction parameters are varied: concentration of iron (III) and hydrogen peroxide, time dependence, pH-value and influence of chloride. Analysis of oxalic acid was performed employing an ion chromatograph equipped with a conductivity detector. The time dependent reaction shows a relatively fast formation of oxalic acid, the optimum yield is achieved after 60 minutes. Compared to the concentration of catechol an excess of hydrogen peroxide as well as a low concentration of iron (III) are required. In absence of chloride the

  2. Effects of simulated acid rain on soil fauna community composition and their ecological niches.

    PubMed

    Wei, Hui; Liu, Wen; Zhang, Jiaen; Qin, Zhong

    2017-01-01

    Acid rain is one of the severest environmental issues globally. Relative to other global changes (e.g., warming, elevated atmospheric [CO2], and nitrogen deposition), however, acid rain has received less attention than its due. Soil fauna play important roles in multiple ecological processes, but how soil fauna community responds to acid rain remains less studied. This microcosm experiment was conducted using latosol with simulated acid rain (SAR) manipulations to observe potential changes in soil fauna community under acid rain stress. Four pH levels, i.e., pH 2.5, 3.5, 4.5, and 5.5, and a neutral control of pH 7.0 were set according to the current pH condition and acidification trend of precipitation in southern China. As expected, we observed that the SAR treatments induced changes in soil fauna community composition and their ecological niches in the tested soil; the treatment effects tended to increase as acidity increased. This could be attributable to the environmental stresses (such as acidity, porosity and oxygen supply) induced by the SAR treatments. In addition to direct acidity effect, we propose that potential changes in permeability and movability of water and oxygen in soils induced by acid rain could also give rise to the observed shifts in soil fauna community composition. These are most likely indirect pathways of acid rain to affect belowground community. Moreover, we found that nematodes, the dominating soil fauna group in this study, moved downwards to mitigate the stress of acid rain. This is probably detrimental to soil fauna in the long term, due to the relatively severer soil conditions in the deep than surface soil layer. Our results suggest that acid rain could change soil fauna community and the vertical distribution of soil fauna groups, consequently changing the underground ecosystem functions such as organic matter decomposition and greenhouse gas emissions.

  3. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China

    PubMed Central

    Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

    2016-01-01

    Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3−-N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many

  4. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream-flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid-forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Streamwater pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by calcium, magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southeast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site.

  5. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Stream water pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southwast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site. 10 references, 2 tables.

  6. 7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Equations for predicting soil loss due to wind erosion... Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The equation for predicting soil loss due to wind in the Wind Erosion Equation (WEQ) is E = f(IKCLV)....

  7. 7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Equations for predicting soil loss due to wind erosion... Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The equation for predicting soil loss due to wind in the Wind Erosion Equation (WEQ) is E = f(IKCLV)....

  8. 7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Equations for predicting soil loss due to wind erosion... Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The equation for predicting soil loss due to wind in the Wind Erosion Equation (WEQ) is E = f(IKCLV)....

  9. 7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Equations for predicting soil loss due to wind erosion... Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The equation for predicting soil loss due to wind in the Wind Erosion Equation (WEQ) is E = f(IKCLV)....

  10. 7 CFR 610.13 - Equations for predicting soil loss due to wind erosion.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Equations for predicting soil loss due to wind erosion... Erosion Prediction Equations § 610.13 Equations for predicting soil loss due to wind erosion. (a) The equation for predicting soil loss due to wind in the Wind Erosion Equation (WEQ) is E = f(IKCLV)....

  11. Barren Acidic Soil Assessment using Seismic Refraction Survey

    NASA Astrophysics Data System (ADS)

    Tajudin, S. A. A.; Abidin, M. H. Z.; Madun, A.; Zawawi, M. H.

    2016-07-01

    Seismic refraction method is one of the geophysics subsurface exploration techniques used to determine subsurface profile characteristics. From past experience, seismic refraction method is commonly used to detect soil layers, overburden, bedrock, etc. However, the application of this method on barren geomaterials remains limited due to several reasons. Hence, this study was performed to evaluate the subsurface profile characteristics of barren acidic soil located in Ayer Hitam, Batu Pahat, Johor using seismic refraction survey. The seismic refraction survey was conducted using ABEM Terraloc MK 8 (seismograph), a sledge hammer weighing 7 kg (source) and 24 units of 10 Hz geophones (receiver). Seismic data processing was performed using OPTIM software which consists of SeisOpt@picker (picking the first arrival and seismic configureuration data input) and SeisOpt@2D (generating 2D image of barren acidic soil based on seismic velocity (primary velocity, Vp) distribution). It was found that the barren acidic soil profile consists of three layers representing residual soil (Vp= 200-400 m/s) at 0-2 m, highly to completely weathered soil (Vp= 500-1800 m/s) at 3-8 m and shale (Vp= 2100-6200 m/s) at 9-20 m depth. Furthermore, result verification was successfully done through the correlation of seismic refraction data based on physical mapping and the geological map of the study area. Finally, it was found that the seismic refraction survey was applicable for subsurface profiling of barren acidic soil as it was very efficient in terms of time, cost, large data coverage and sustainable.

  12. Chloroacetic acids in European soils and vegetation.

    PubMed

    Peters, Ruud J B

    2003-04-01

    Trichloroacetic acid (TCA) and dichloroacetic acid (DCA) are possible minor atmospheric degradation products of perchloroethylene and trichloroethylene, respectively. These acids may be wet- or dry-deposited from the atmosphere to land surfaces and hence possibly affect plant growth. However, the existing database on TCA levels in soil is limited to a few studies carried out in the late 1980's and the early to mid-1990's and it was concluded that there is a need for further measurements of concentrations of TCA and DCA in soils. In this study soil samples from 10 locations in 5 European countries, as well as vegetation samples, and a limited number of rainwater and air samples were collected and analysed for DCA and TCA to determine the concentrations of these compounds. An isotope dilution method using GC-MS was used for the determination of these acids in the samples. The method was briefly validated and the performance characteristics are presented. The results of the analysis of the soil samples show that the DCA and TCA concentrations in soil from different sites in Europe are more or less comparable, with the exception of Germany, especially Freudenstadt, where significantly higher TCA concentrations (up to 12 microg kg(-1) dw) were found. The average DCA and TCA concentrations in soil in this study were 0.25 +/- 0.12 and 0.64 +/- 1.40 microg kg(-1) dw, respectively. Generally, the concentration in soils from forest areas are about twice those from open-land areas. The DCA and TCA concentrations in vegetation samples ranged from 2.1 to 73 microg kg(-1) dw for DCA and from 4.7 to 17 microg kg(-1) dw for TCA. Thus, the concentrations in vegetation samples are 10-20 times higher than the soil concentrations. DCA and TCA concentrations in wet deposition samples and air samples collected in The Netherlands were 0.14 and 0.15 microg l(-1) for wet deposition samples and <0.5 and 0.7 ng m(-3) for air samples respectively. For these samples taken in The Netherlands

  13. Modeling the contribution of soil fauna to litter decomposition influenced by acidic deposition

    SciTech Connect

    Cai, B.; Loucks, O.L; Kuperman, R. Argonne National Lab., IL )

    1993-06-01

    The effect of acidic deposition on soil pH and therefore on soil invertebrates and litter decomposition is being investigated in oak-hickory forests across a three-state, midwest, pollution gradient. The role of soil invertebrates has been assessed previously through the use of feeding, assimilation and respiratory rates. These energetic parameters depend strongly on the form of the allometric equations which have been improved here by incorporating uncertainties in body and population size. Results show that changes in reproduction and turnover dynamics of soil invertebrates (particularly of earthworms) due to acid-induced changes in soil pH explains observed patterns in litter depth.

  14. 7 CFR 610.12 - Equations for predicting soil loss due to water erosion.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... erosion. 610.12 Section 610.12 Agriculture Regulations of the Department of Agriculture (Continued... ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a) The equation for predicting soil loss due to erosion for both the USLE and the RUSLE is A = R ×...

  15. 7 CFR 610.12 - Equations for predicting soil loss due to water erosion.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... erosion. 610.12 Section 610.12 Agriculture Regulations of the Department of Agriculture (Continued... ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a) The equation for predicting soil loss due to erosion for both the USLE and the RUSLE is A = R ×...

  16. 7 CFR 610.12 - Equations for predicting soil loss due to water erosion.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... erosion. 610.12 Section 610.12 Agriculture Regulations of the Department of Agriculture (Continued... ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a) The equation for predicting soil loss due to erosion for both the USLE and the RUSLE is A = R ×...

  17. 7 CFR 610.12 - Equations for predicting soil loss due to water erosion.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... erosion. 610.12 Section 610.12 Agriculture Regulations of the Department of Agriculture (Continued... ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a) The equation for predicting soil loss due to erosion for both the USLE and the RUSLE is A = R ×...

  18. 7 CFR 610.12 - Equations for predicting soil loss due to water erosion.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... erosion. 610.12 Section 610.12 Agriculture Regulations of the Department of Agriculture (Continued... ASSISTANCE Soil Erosion Prediction Equations § 610.12 Equations for predicting soil loss due to water erosion. (a) The equation for predicting soil loss due to erosion for both the USLE and the RUSLE is A = R ×...

  19. Influence of ameliorating soil acidity with dolomite on the priming of soil C content and CO2 emission.

    PubMed

    Shaaban, Muhammad; Wu, Lei; Peng, Qi-An; van Zwieten, Lukas; Chhajro, Muhammad Afzal; Wu, Yupeng; Lin, Shan; Ahmed, Muhammad Mahmood; Khalid, Muhammad Salman; Abid, Muhammad; Hu, Ronggui

    2017-02-21

    Lime or dolomite is commonly implemented to ameliorate soil acidity. However, the impact of dolomite on CO2 emissions from acidic soils is largely unknown. A 53-day laboratory study was carried out to investigate CO2 emissions by applying dolomite to an acidic Acrisol (rice-rapeseed rotation [RR soil]) and a Ferralsol (rice-fallow/flooded rotation [RF soil]). Dolomite was dosed at 0, 0.5, and 1.5 g 100 g(-1) soil, herein referred to as CK, L, and H, respectively. The soil pH(H2O) increased from 5.25 to 7.03 and 7.62 in L and H treatments of the RR soil and from 5.52 to 7.27 and 7.77 in L and H treatments of the RF soil, respectively. Dolomite application significantly (p ≤ 0.001) increased CO2 emissions in both RR and RF soils, with higher emissions in H as compared to L dose of dolomite. The cumulative CO2 emissions with H dose of dolomite were greater 136% in the RR soil and 149% in the RF soil as compared to CK, respectively. Dissolved organic carbon (DOC) and microbial biomass carbon (MBC) increased and reached at 193 and 431 mg kg(-1) in the RR soil and 244 and 481 mg kg(-1) in the RF soil by H treatments. The NH4(-)-N and NO3(-)-N were also increased by dolomite application. The increase in C and N contents stimulated microbial activities and therefore higher respiration in dolomite-treated soil as compared to untreated. The results suggest that CO2 release in dolomite-treated soils was due to the priming of soil C content rather than chemical reactions.

  20. Acid soil infertility effects on peanut yields and yield components

    SciTech Connect

    Blamey, F.P.C.

    1983-01-01

    The interpretation of soil amelioration experiments with peanuts is made difficult by the unpredictibility of the crop and by the many factors altered when ameliorating acid soils. The present study was conducted to investigate the effects of lime and gypsum applications on peanut kernel yield via the three first order yield components, pods per ha, kernels per pod, and kernel mass. On an acid medium sandy loam soil (typic Plinthustult), liming resulted in a highly significant kernel yield increase of 117% whereas gypsum applications were of no significant benefit. As indicated by path coefficient analysis, an increase in the number of pods per ha was markedly more important in increasing yield than an increase in either the number of kernels per pod or kernel mass. Furthermore, exch. Al was found to be particularly detrimental to pod number. It was postulated that poor peanut yields resulting from acid soil infertility were mainly due to the depressive effect of exch. Al on pod number. Exch. Ca appeared to play a secondary role by ameliorating the adverse effects of exch. Al.

  1. Sorption of tebuconazole onto selected soil minerals and humic acids.

    PubMed

    Cadková, Eva; Komárek, Michael; Kaliszová, Regina; Koudelková, Věra; Dvořák, Jiří; Vaněk, Aleš

    2012-01-01

    The aim of the present study was to investigate tebuconazole sorption on common soil minerals (birnessite, ferrihydrite, goethite, calcite and illite) and humic acids (representing soil organic matter). Tebuconazole was used (i) in the commercial form Horizon 250 EW and (ii) as an analytical grade pure chemical. In the experiment with the commercially available tebuconazole, a significant pH-dependent sorption onto the oxides was observed (decreasing sorption with increasing pH). The highest sorption was found for ferrihydrite due to its high specific surface area, followed by humic acids, birnessite, goethite and illite. No detectable sorption was found for calcite. The sorption of analytical grade tebuconazole on all selected minerals was significantly lower compared to the commercial product. The sorption was the highest for humic acids, followed by ferrihydrite and illite and almost negligible for goethite and birnessite without any pH dependence. Again, no sorption was observed for calcite. The differences in sorption of the commercially available and analytical grade tebuconazole can be attributed to the additives (e.g., solvents) present in the commercial product. This work proved the importance of soil mineralogy and composition of the commercially available pesticides on the behavior of tebuconazole in soils.

  2. Reduced nitrification and abundance of ammonia-oxidizing bacteria in acidic soil amended with biochar.

    PubMed

    Wang, Zhenyu; Zong, Haiying; Zheng, Hao; Liu, Guocheng; Chen, Lei; Xing, Baoshan

    2015-11-01

    Adding biochar into soils has potential to manipulate soil nitrification process due to its impacts on nitrogen (N) cycling, however, the exact mechanisms underlying the alteration of nitrification process in soils are still not clear. Nitrification in an acidic orchard soil amended with peanut shell biochar (PBC) produced at 400 °C was investigated. Nitrification was weakened by PBC addition due to the decreased NH4(+)-N content and reduced ammonia-oxidizing bacteria (AOB) abundance in PBC-amended soils. Adding phenolic compounds (PHCs) free biochar (PBC-P) increased the AOB abundance and the DGGE band number, indicating that PHCs remaining in the PBC likely reduced AOB abundance and diversity. However, PBC addition stimulated rape growth and increased N bioavailability. Overall, adding PBC could suppress the nitrification process and improve N bioavailability in the agricultural soils, and thus possibly mitigate the environmental negative impacts and improving N use efficiency in the acidic soils added with N fertilizer.

  3. Influence of different forms of acidities on soil microbiological properties and enzyme activities at an acid mine drainage contaminated site.

    PubMed

    Sahoo, Prafulla Kumar; Bhattacharyya, Pradip; Tripathy, Subhasish; Equeenuddin, Sk Md; Panigrahi, M K

    2010-07-15

    Assessment of microbial parameters, viz. microbial biomass, fluorescence diacetate, microbial respiration, acid phosphatase, beta-glucosidase and urease with respect to acidity helps in evaluating the quality of soils. This study was conducted to investigate the effects of different forms of acidities on soil microbial parameters in an acid mine drainage contaminated site around coal deposits in Jainta Hills of India. Total potential and exchangeable acidity, extractable and exchangeable aluminium were significantly higher in contaminated soil compared to the baseline (p<0.01). Different forms of acidity were significantly and positively correlated with each other (p<0.05). Further, all microbial properties were positively and significantly correlated with organic carbon and clay (p<0.05). The ratios of microbial parameters with organic carbon were negatively correlated with different forms of acidity. Principal component analysis and cluster analyses showed that the microbial activities are not directly influenced by the total potential acidity and extractable aluminium. Though acid mine drainage affected soils had higher microbial biomass and activities due to higher organic matter content than those of the baseline soils, the ratios of microbial parameters/organic carbon indicated suppression of microbial growth and activities due to acidity stress.

  4. Bromine accumulation in acidic black colluvial soils

    NASA Astrophysics Data System (ADS)

    Cortizas, Antonio Martínez; Vázquez, Cruz Ferro; Kaal, Joeri; Biester, Harald; Casais, Manuela Costa; Rodríguez, Teresa Taboada; Lado, Luis Rodríguez

    2016-02-01

    Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (<50 μm) fraction were on average 3-times higher than those (17-250 μg g-1) in the fine earth (<2 mm), the former containing almost all bromine (90 ± 5%). Inventories were between 148 and 314 g m-2, indicating a rather large variability in a small area, and total estimated retention was low (6-16%). The degree of SOM bromination, expressed as the Br/C molar ratio, varied between 0.03 and 1.20 mmol Br/mol C. The ratio was highly correlated (n = 23, r2 0.88, p < 0.01) with the age of the SOM for the last ∼12 ka. Partial least squares modeling indicates that bromine concentration depends on the amount of organic matter stabilized as aluminium-OM associations, and to a lesser extent on soil acidity (pH) and iron-OM associations. Thus, at scales of thousands of years, bromine accumulation in acidic soils is linked to the pool of metal-clay-stabilized organic matter.

  5. Changes in soil properties and soil cover structure due to intensive erosion and accumulation processes in loess soils

    NASA Astrophysics Data System (ADS)

    Zadorova, Tereza; Penizek, Vit; Jaksik, Ondrej; Kodesova, Radka; Jirku, Veronika; Fer, Miroslav

    2010-05-01

    concave parts of the slope and at the toeslope, the Corg content in the plough layer is lower due to an admixture of non-humus material transported from the steep parts of the plot. Nevertheless, the deeper (0.7 - 2 m), buried parts of the colluvial profiles are very rich in organic carbon (up to 4 %). These horizons may represent fossil chernic horizons of former Chernozems, buried by intensive sedimentation of humic material. Similar variability was found in carbonate content values, always due to amount of loess admixture in the plough horizon. While the soil structure stability, depending strongly on humus content, was the highest in the Chernozem unit, in the eroded parts it was highly unstable. Changes in the cation exchange capacity and pH are less distinctive. CEC slightly increases in humus-rich soils and pH is higher in the eroded parts of the plot due to the loess exposition. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of the Czech Republic (grant No. GA CR 526/08/0434) and the Ministry of Education, Youth and Sports of the Czech Republic (grant No. MSM 6046070901).

  6. Differential Soil Acidity Tolerance of Tropical Legume Cover Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In tropical regions, soil acidity and low soil fertility are the most important yield limiting factors for sustainable crop production. Using legume cover crops as mulch is an important strategy not only to protect the soil loss from erosion but also ameliorating soil fertility. Information is limit...

  7. Effects Due to Rhizospheric Soil Application of an Antagonistic Bacterial Endophyte on Native Bacterial Community and Its Survival in Soil: A Case Study with Pseudomonas aeruginosa from Banana

    PubMed Central

    Thomas, Pious; Sekhar, Aparna C.

    2016-01-01

    Effective translation of research findings from laboratory to agricultural fields is essential for the success of biocontrol or growth promotion trials employing beneficial microorganisms. The rhizosphere is to be viewed holistically as a dynamic ecological niche comprising of diverse microorganisms including competitors and noxious antagonists to the bio-inoculant. This study was undertaken to assess the effects due to the soil application of an endophytic bacterium with multiple pathogen antagonistic potential on native bacterial community and its sustenance in agricultural soil. Pseudomonas aeruginosa was employed as a model system considering its frequent isolation as an endophyte, wide antagonistic effects reported against different phytopathogens and soil pests, and that the species is a known human pathogen which makes its usage in agriculture precarious. Employing the strain ‘GNS.13.2a’ from banana, its survival in field soil and the effects upon soil inoculation were investigated by monitoring total culturable bacterial fraction as the representative indicator of soil microbial community. Serial dilution plating of uninoculated control versus P. aeruginosa inoculated soil from banana rhizosphere indicated a significant reduction in native bacterial cfu soon after inoculation compared with control soil as assessed on cetrimide- nalidixic acid selective medium against nutrient agar. Sampling on day-4 showed a significant reduction in P. aeruginosa cfu in inoculated soil and a continuous dip thereafter registering >99% reduction within 1 week while the native bacterial population resurged with cfu restoration on par with control. This was validated in contained trials with banana plants. Conversely, P. aeruginosa showed static cfu or proliferation in axenic-soil. Lateral introduction of soil microbiome in P. aeruginosa established soil under axenic conditions or its co-incubation with soil microbiota in suspension indicated significant adverse effects by

  8. Aliphatic, Cyclic, and Aromatic Organic Acids, Vitamins, and Carbohydrates in Soil: A Review

    PubMed Central

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-01-01

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research. PMID:24319374

  9. Aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil: a review.

    PubMed

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-11-10

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research.

  10. Natural abiotic formation of oxalic acid in soils: results from aromatic model compounds and soil samples.

    PubMed

    Studenroth, Sabine; Huber, Stefan G; Kotte, Karsten; Schöler, Heinz F

    2013-02-05

    Oxalic acid is the smallest dicarboxylic acid and plays an important role in soil processes (e.g., mineral weathering and metal detoxification in plants). We have first proven its abiotic formation in soils and investigated natural abiotic degradation processes based on the oxidation of soil organic matter, enhanced by Fe(3+) and H(2)O(2) as hydroxyl radical suppliers. Experiments with the model compound catechol and further hydroxylated benzenes were performed to examine a common degradation pathway and to presume a general formation mechanism of oxalic acid. Two soil samples were tested for the release of oxalic acid and the potential effects of various soil parameters on oxalic acid formation. Additionally, the soil samples were treated with different soil sterilization methods to prove the oxalic acid formation under abiotic soil conditions. Different series of model experiments were conducted to determine a range of factors including Fe(3+), H(2)O(2), reaction time, pH, and chloride concentration on oxalic acid formation. Under certain conditions, catechol is degraded up to 65.6% to oxalic acid referring to carbon. In serial experiments with two soil samples, oxalic acid was produced, and the obtained results are suggestive of an abiotic degradation process. In conclusion, Fenton-like conditions with low Fe(3+) concentrations and an excess of H(2)O(2) as well as acidic conditions were required for an optimal oxalic acid formation. The presence of chloride reduced oxalic acid formation.

  11. [Effects of low molecular weight organic acids on speciation of exogenous Cu in an acid soil].

    PubMed

    Huang, Guo-Yong; Fu, Qing-Ling; Zhu, Jun; Wan, Tian-Ying; Hu, Hong-Qing

    2014-08-01

    In order to ascertain the effect of LMWOA (citric acid, tartaric acid, oxalic acid) on Cu-contaminated soils and to investigate the change of Cu species, a red soil derived from quartz sandstone deposit was added by Cu (copper) in the form of CuSO4 x 5H2O so as to simulate soil Cu pollution, keeping the additional Cu concentrations were 0, 100, 200, 400 mg x kg(-1) respectively. After 9 months, different LMWOA was also added into the simulated soil, keeping the additional LMWOAs in soil were 0, 5, 10, 20 mmol x kg(-1) respectively. After 2 weeks incubation, the modified sequential extraction method on BCR (European Communities Bureau of Reference) was used to evaluate the effects of these LMWOAs on the changes of copper forms in soil. The result showed that the percentage of weak acid dissolved Cu, the most effective form in the soil increased with three organic acids increase in quantity in the simulated polluted soil. And there was a good activation effect on Cu in the soil when organic acid added. Activation effects on Cu increased with concentration of citric acid increasing, but it showed a rise trend before they are basically remained unchanged in the case of tartaric acid and oxalic acid added in the soil. On the contrary, the state of the reduction of copper which was regarded as a complement for effective state decreased with the increased concentration of organic acid in the soil, especially with citric acid. When 20 mmol x kg(-1) oxalic acid and citric acid were added into the soil, the activation effect was the best; whereas for tartaric, the concentration was 10 mmol x kg(-1). In general, the effect on the changes of Cu forms in the soil is citric acid > tartaric acid > oxalic acid.

  12. Reduced carbon sequestration potential of biochar in acidic soil.

    PubMed

    Sheng, Yaqi; Zhan, Yu; Zhu, Lizhong

    2016-12-01

    Biochar application in soil has been proposed as a promising method for carbon sequestration. While factors affecting its carbon sequestration potential have been widely investigated, the number of studies on the effect of soil pH is limited. To investigate the carbon sequestration potential of biochar across a series of soil pH levels, the total carbon emission, CO2 release from inorganic carbon, and phospholipid fatty acids (PLFAs) of six soils with various pH levels were compared after the addition of straw biochar produced at different pyrolysis temperatures. The results show that the acidic soils released more CO2 (1.5-3.5 times higher than the control) after the application of biochar compared with neutral and alkaline soils. The degradation of both native soil organic carbon (SOC) and biochar were accelerated. More inorganic CO2 release in acidic soil contributed to the increased degradation of biochar. Higher proportion of gram-positive bacteria in acidic soil (25%-36%) was responsible for the enhanced biochar degradation and simultaneously co-metabolism of SOC. In addition, lower substrate limitation for bacteria, indicated by higher C-O stretching after the biochar application in the acidic soil, also caused more CO2 release. In addition to the soil pH, other factors such as clay contents and experimental duration also affected the phsico-chemical and biotic processes of SOC dynamics. Gram-negative/gram-positive bacteria ratio was found to be negatively related to priming effects, and suggested to serve as an indicator for priming effect. In general, the carbon sequestration potential of rice-straw biochar in soil reduced along with the decrease of soil pH especially in a short-term. Given wide spread of acidic soils in China, carbon sequestration potential of biochar may be overestimated without taking into account the impact of soil pH.

  13. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste.

    PubMed

    Hamdi, Noureddine; Srasra, Ezzeddine

    2013-01-01

    Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10(-10), 2.08 × 10(-9) and 6.8 × 10(-10)m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m(3)). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH=2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m(3)) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

  14. Differential soil acidity tolerance of dry bean genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil acidity is a major yield limiting factors for bean production in the tropical regions. Using soil acidity tolerant genotypes is an important strategy in improving bean yields and reducing cost of production. A greenhouse experiment was conducted with the objective of evaluating 20 dry bean geno...

  15. Phytoremediation of Cu and Zn by vetiver grass in mine soils amended with humic acids.

    PubMed

    Vargas, Carmen; Pérez-Esteban, Javier; Escolástico, Consuelo; Masaguer, Alberto; Moliner, Ana

    2016-07-01

    Phytoremediation of contaminated mine soils requires the use of fast-growing, deep-rooted, high-biomass, and metal-tolerant plants with the application of soil amendments that promote metal uptake by plants. A pot experiment was performed to evaluate the combined use of vetiver grass (Chrysopogon zizanioides) and humic acid for phytoremediation of Cu and Zn in mine soils. Vetiver plants were grown in soil samples collected from two mine sites of Spain mixed with a commercial humic acid derived from leonardite at doses of 0, 2, 10, and 20 g kg(-1). Plant metal concentrations and biomass were measured and metal bioavailability in soils was determined by a low molecular weight organic acid extraction. Results showed that humic acid addition decreased organic acid-extractable metals in soil. Although this extraction method is used to estimate bioavailability of metals, it was not a good estimator under these conditions due to competition with the strong chelators in the added humic acid. High doses of humic acid also promoted root growth and increased Cu concentrations in plants due to formation of soluble metal-organic complexes, which enhanced removal of this metal from soil and its accumulation in roots. Although humic acid was not able to improve Zn uptake, it managed to reduce translocation of Zn and Cu to aerial parts of plants. Vetiver resulted unsuitable for phytoextraction, but our study showed that the combined use of this species with humic acid at 10-20 g kg(-1) could be an effective strategy for phytostabilization of mine soils.

  16. Changes in soil quality due to converting Pinus to Eucalyptus plantations and subsequent successive Eucalyptus planting in southern China

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Zheng, H.; Chen, F. L.; Ouyang, Z. Y.; Wang, Y.; Wu, Y. F.; Lan, J.; Fu, M.; Xiang, X. W.

    2014-09-01

    Plants play a key role in maintaining soil quality, but long-term changes in soil quality due to plant species change and successive planting are rarely reported. Using the space-for-time substitution method, adjacent plantations of Pinus and 1st, 2nd, 3rd and 4th generations of Eucalyptus in Guangxi, China were used to study changes in soil quality caused by converting Pinus to Eucalyptus and successive Eucalyptus planting. Soil chemical and biological properties were measured and a soil quality index (SQI) was calculated. Soil organic carbon, total nitrogen, alkaline hydrolytic nitrogen, microbial biomass carbon, microbial biomass nitrogen, cellobiosidase, phenol oxidase, peroxidase and acid phosphatase activities significantly decreased in the 1st and 2nd generations of Eucalyptus plantations after conversion from Pinus to Eucalyptus but gradually recovered in the 3rd and 4th generations. Soil total and available potassium were significantly lower, but total phosphorus was significantly higher in Eucalyptus plantations compared to the Pinus plantation. As an integrated indicator, SQI was highest in the Pinus plantation (0.92), but decreased to 0.24 and 0.13 in the 1st and 2nd generations of Eucalyptus plantations, respectively. However, it recovered to 0.36 and 0.38 in the 3rd and 4th generations, respectively. Changing tree species, reclamation and fertilization may have contributed to the "U" shaped change observed in soil quality during conversion of Pinus to Eucalyptus and successive Eucalyptus planting. Litter retention, keeping understory coverage, and reducing soil disturbance during logging and subsequent establishment of the next rotation should be considered to help improving soil quality during plantation management.

  17. Acidity field of soils as ion-exchange systems and the diagnostics of genetic soil horizons

    NASA Astrophysics Data System (ADS)

    Kokotov, Yu. A.; Sukhacheva, E. Yu.; Aparin, B. F.

    2014-12-01

    For the comprehensive description of the acidity of a two-phase ion-exchange system, we should analyze two curves of the ionite titration by a strong base in water and salt solutions and find the quantitative relationships between the corresponding pH characteristics. An idea of the three-dimensional field of acidity of ion-exchange systems (the phase space of the soil acidity characteristics) and its three two-dimensional projections is suggested. For soils, three interrelated characteristics—the pH values of the salt and water extracts and the degree of base saturation—can serve as spatial coordinates for the acidity field. Representation of factual data in this field makes it possible to compare and analyze the acidity characteristics of different soils and soil horizons and to determine their specific features. Differentiation of the field into separate volumes allows one to present the data in a discrete form. We have studied the distribution patterns of the groups of soil horizons from Leningrad oblast and other regions of northwestern Russia in the acidity field. The studied samples are grouped in different partially overlapping areas of the projections of the acidity field. The results of this grouping attest to the correctness of the modern classification of Russian soils. A notion of the characteristic soil area in the acidity field is suggested; it can be applied to all the soils with a leaching soil water regime.

  18. Improved analyses for soil carbohydrates, amino acids, and phenols: Tools for understanding soil processes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A process-level understanding of soil carbon(C) and nitrogen (N) cycling will be facilitated by precise measurement of biochemical compounds in soil organic matter. This review summarizes some recent developments in analyses for soil carbohydrates, amino compounds (amino acids and amino sugars), and...

  19. Can Tomato Inoculation with Trichoderma Compensate Yield and Soil Health Deficiency due to Soil Salinity?

    NASA Astrophysics Data System (ADS)

    Wagner, Karl; Apostolakis, Antonios; Daliakopoulos, Ioannis; Tsanis, Ioannis

    2016-04-01

    Soil salinity is a major soil degradation threat, especially for arid coastal environments where it hinders agricultural production and soil health. Protected horticultural crops in the Mediterranean region, typically under deficit irrigation and intensive cultivation practices, have to cope with increasing irrigation water and soil salinization. This study quantifies the beneficial effects of the Trichoderma harzianum (TH) on the sustainable production of Solanum lycopersicum (tomato), a major greenhouse crop of the RECARE project Case Study in Greece, the semi-arid coastal Timpaki basin in south-central Crete. 20 vigorous 20-day-old Solanum lycopersicum L. cv Elpida seedlings are treated with TH fungi (T) or without (N) and transplanted into 35 L pots under greenhouse conditions. Use of local planting soil with initial Electrical Conductivity (ECe) 1.8 dS m-1 and local cultivation practices aim to simulate the prevailing conditions at the Case Study. In order to simulate seawater intrusion affected irrigation, plants are drip irrigated with two NaCl treatments: slightly (S) saline (ECw = 1.1 dS m-1) and moderately (M) saline water (ECw = 3.5 dS m-1), resulting to very high and excessively high ECe, respectively. Preliminary analysis of below and aboveground biomass, soil quality, salinity, and biodiversity indicators, suggest that TH pre-inoculation of tomato plants at both S and M treatments improve yield, soil biodiversity and overall soil health.

  20. Modeling the influence of organic acids on soil weathering

    USGS Publications Warehouse

    Lawrence, Corey R.; Harden, Jennifer W.; Maher, Kate

    2014-01-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  1. Effects of Fe oxide on N transformations in subtropical acid soils

    PubMed Central

    Jiang, Xianjun; Xin, Xiaoping; Li, Shiwei; Zhou, Junchao; Zhu, Tongbin; Müller, Christopher; Cai, Zucong; Wright, Alan L.

    2015-01-01

    Subtropical ecosystems are often characterized by high N cycling rates, but net nitrification rates are often low in subtropical acid soils. NO3−-N immobilization into organic N may be a contributing factor to understand the observed low net nitrification rates in these acid soils. The effects of Fe oxide and organic matter on soil N transformations were evaluated using a 15N tracing study. Soil net nitrification was low for highly acidic yellow soil (Ferralsols), but gross ammonia oxidation was 7 times higher than net nitrification. In weakly acidic purple soil (Cambisols), net nitrification was 8 times higher than in Ferralsols. The addition of 5% Fe oxide to Cambisols, reduced the net nitrification rate to a negative rate, while NO3−-N immobilization rate increased 8 fold. NO3−-N immobilization was also observed in Ferralsols which contained high Fe oxides levels. A possible mechanism for these reactions could be stimulation of NO3−-N immobilization by Fe oxide which promoted the abiotic formation of nitrogenous polymers, suggesting that the absence of net nitrification in some highly acid soils may be due to high rates of NO3−-N immobilization caused by high Fe oxide content rather than a low pH. PMID:25722059

  2. Mathematical modeling of acid deposition due to radiation fog

    SciTech Connect

    Pandis, S.N.; Seinfeld, J.H. )

    1989-09-20

    A Lagrangian model has been developed to study acidic deposition due to radiation fog. The model couples submodels describing the development and dissipation of radiation fog, the gas-phase chemistry and transfer, and the aqueous-phase chemistry. The model is applied to a radiation fog episode in Bakersfield in the San Joaquin Valley of California over the period January 4--5 1985. Model predictions for temperature profile, fog development, liquid water content, gas-phase concentrations of SO{sub 2}, HNO{sub 3}, and NH{sub 3}, {ital p}H, aqueous-phase concentrations of OS{sup 2{minus}}{sub 4}, NH{sup +}{sub 4}, and NO{sup {minus}}{sub 3}, and finally deposition rates of the above ions are compared with the observed values. The deposition rates of the major ions are predicted to increase significantly during the fog episode, the most notable being the increase of sulfate deposition. Pathways for sulfate production that are of secondary importance in a cloud environment may become signficant in a fog. Expressing the mean droplet settling velocity as a function of liquid water content is found to be quite influential in the model's predictions. {copyright} American Geophysical Union 1989

  3. Glyphosate and aminomethylphosphonic acid chronic risk assessment for soil biota.

    PubMed

    von Mérey, Georg; Manson, Philip S; Mehrsheikh, Akbar; Sutton, Peter; Levine, Steven L

    2016-11-01

    Glyphosate is a broad-spectrum herbicide used widely in agriculture, horticulture, private gardens, and public infrastructure, where it is applied to areas such as roadsides, railway tracks, and parks to control the growth of weeds. The exposure risk from glyphosate and the primary soil metabolite aminomethylphosphonic acid (AMPA) on representative species of earthworms, springtails, and predatory soil mites and the effects on nitrogen-transformation processes by soil microorganisms were assessed under laboratory conditions based on internationally recognized guidelines. For earthworms, the reproductive no-observed-effect concentration (NOEC) was 472.8 mg glyphosate acid equivalent (a.e.)/kg dry soil, which was the highest concentration tested, and 198.1 mg/kg dry soil for AMPA. For predatory mites, the reproductive NOEC was 472.8 mg a.e./kg dry soil for glyphosate and 320 mg/kg dry soil for AMPA, the highest concentrations tested. For springtails, the reproductive NOEC was 472.8 mg a.e./kg dry soil for glyphosate and 315 mg/kg dry soil for AMPA, the highest concentrations tested. Soil nitrogen-transformation processes were unaffected by glyphosate and AMPA at 33.1 mg a.e./kg soil and 160 mg/kg soil, respectively. Comparison of these endpoints with worst-case soil concentrations expected for glyphosate (6.62 mg a.e./kg dry soil) and AMPA (6.18 mg/kg dry soil) for annual applications at the highest annual rate of 4.32 kg a.e./ha indicate very low likelihood of adverse effects on soil biota. Environ Toxicol Chem 2016;35:2742-2752. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

  4. Influence of humic acid applications on soil physicochemical properties

    NASA Astrophysics Data System (ADS)

    Gümüş, İ.; Şeker, C.

    2015-09-01

    Soil structure is often said to be the key to soil productivity since a fertile soil, with desirable soil structure and adequate moisture supply, constitutes a productive soil. Soil structure influences soil water movement and retention, erosion, crusting, nutrient recycling, root penetration and crop yield. The objective of this work is to study, humic acid (HA) application on some physical and chemical properties in weak structured soils investigated. The approach involved establishing a plot experiment in the laboratory conditions. Different rates of HA (control, 0.5, 1, 2 and 4 %) were applied to soil at three incubation periods (21, 42 and 62 days). At the end of the each incubation period, the changes in physicochemical properties were measured. Generally, HA addition increased EC values at the all incubation periods. HA applications decreased soil modulus of rupture. Application of HA at the rate of 4 % was significantly increased soil organic carbon contents. HA applications at the rate of 4 % significantly increased both mean soil total nitrogen content and aggregate stability after at three incubation periods (p < 0.05). Therefore, HA was potential to improve structure of soil in short term.

  5. Using marble wastes as a soil amendment for acidic soil neutralization.

    PubMed

    Tozsin, Gulsen; Arol, Ali Ihsan; Oztas, Taskin; Kalkan, Ekrem

    2014-01-15

    One of the most important factors limiting plant growth is soil pH. The objective of this study is to determine the effectiveness of marble waste applications on neutralization of soil acidity. Marble quarry waste (MQW) and marble cutting waste (MCW) were applied to an acid soil at different rates and their effectiveness on neutralization was evaluated by a laboratory incubation test. The results showed that soil pH increased from 4.71 to 6.36 and 6.84 by applications of MCW and MQW, respectively. It was suggested that MQW and MCW could be used as soil amendments for the neutralization of acid soils and thus the negative impact of marble wastes on the environment could be reduced.

  6. Changes of soil pore system due to soil macrofauna: an experimental approach to study the contribution of different taxa

    NASA Astrophysics Data System (ADS)

    Gargiulo, Laura; Buscemi, Gilda; Mele, Giacomo; Terribile, Fabio

    2015-04-01

    Soil fauna contributes to the ecosystem functioning, for example, by means of its direct influence on soil structure which modifies the physical environment of the microbial community. Changes in habitat structure due to soil fauna activities can influence resource availability, species' abundances, and community composition of soil microorganisms. X-ray tomography has been increasingly used to obtain precise and non-destructive analysis mostly of the macroporosity resulting from earthworm activity in repacked soil cores. However also other macrofauna species contribute in different manner and extent to the modification of soil pore system, and then to the soil functioning, by means of their burrows and bioturbation activity. In this work we have developed an experimental approach based on the use of repacked soil mesocosms specifically constructed for the purpose of distinguish separately the contribution to soil structure changes of different organisms naturally present in field or inoculated in laboratory. Six different orders of macrofauna were studied and after four weeks of fauna activity the cores were imaged using a medical X-ray tomograph. Three-dimensional image processing was used in order to obtain 3D reconstructions and preliminary analysis of the identified biopores. In addition to the earthworms (Haplotaxida, genus Lombricus), among the studied taxa, Embioptera showed the most intense burrowing activity, while Coleoptera larvae (sp. Elater sanguineus) and Julida (class Diplopoda) produced the thickest pore network in our mesocosms. The used experimental approach showed a promising potential to provide new useful information about the widely differentiated contribution of many types of macrofauna to the modification of soil pore system.

  7. Comparison of classic with novel in situ extraction of soil amino acids from grassland soil

    NASA Astrophysics Data System (ADS)

    Chen, J.; Williams, D. G.

    2012-12-01

    Characterization of organic and inorganic soil nitrogen availability is important for determining ecosystem response to global change, as nitrogen limitation is often a major constraint on ecosystem productivity. Classic methods of soil nitrogen extraction involve field collection of soil samples and disturbance of soil aggregates during processing. A novel method of soil amino acid extraction is described that allows the collection of semi-sterile soil water extracts in situ with minimal disturbance to soils. Comparison of samples collected using this novel method to samples collected in parallel using classic methods developed by Brookes et al. 1985 and Kielland 1994 revealed different detectable amino acid N pools relative to ammonium. Glutamate and arginine comprised the highest amino acid N pools from extracts collected from a semiarid grassland site using this new method of extraction. In contrast, samples collected and extracted using the classic method contained higher relative levels of serine, glycine and glutamate. The amounts of dominant amino acids relative to ammonium were significantly greater using the classic method compared to the new method. These observed higher ratios of amino acids to ammonium are likely the result of additional amino acid inputs by lysis of microorganisms which are not removed when filtering in the classic method. Disturbance associated with classic methods of soil N determination may have led to alterations in the quantity and distribution of ammonium and amino acids in extracts. Minimizing disturbance of soil aggregates when sampling nitrogen pools and selection of an appropriate filter for collecting free amino acids may be important for accurately determining nitrogen availability to plant roots and soil microbes.

  8. WSA index as an indicator of soil degradation due to erosion

    NASA Astrophysics Data System (ADS)

    Jaksik, Ondrej; Kodesova, Radka; Schmidtova, Zuzana; Kubis, Adam; Fer, Miroslav; Klement, Ales; Nikodem, Antonin

    2014-05-01

    Knowledge of spatial distribution of soil aggregate stability as an indicator of soil degradation vulnerability is required for many scientific and practical environmental studies. The goal of our study was to assess predisposition of different soil types to change aggregate stability due to erosion. Five agriculture arable lands with different soil types were chosen. The common feature of these sites is relatively large slope and thus soils are impacted by water erosion. The first studied area was in Brumovice. The original soil type was Haplic Chernozem on loess, which was due to erosion changed into Regosol (steep parts) and Colluvial soil (base slope and the tributary valley). A similar process has been described at other four locations Vidim, Sedlcany, Zelezna and Hostoun, where the original soil types were Haplic Luvisol on loess and Haplic Cambisol on gneiss, Haplic Cambisol on shales, and Calcaric Cambisol on marlstone, respectively. The regular and semi-regular soil sampling grids were set at all five sites. The basic soil properties were measured and stability of soil aggregates (WSA index) was evaluated. In all cases, the higher aggregates stability was observed in soils, which were not (or only slightly) affected by water erosion and at base slope and the tributary valley (eroded soil particle accumulation). The lowest aggregate stability was measured at the steepest parts. When comparing individual sites, the highest WSA index, e.g. aggregate stability, was found in Sedlcany (Cambisol). Lower WSA indexes were measured on aggregates from Hostoun (Cambisol), Zelezna (Cambisol), Vidim (Luvisol) and the lowest values were obtained in Brumovice (Chernozem). The largest WSA indexes for Cambisols in comparison to Luvisols and Chernozem could be attributed to higher organic matter content and presence of iron oxides. Slightly higher aggregate stability of Luvisols in comparison to Chernozem, could be explained by the positive influence of clay (especially in

  9. Declines in Soil pH due to Anthropogenic Nitrogen Inputs Alter Buffering and Exchange Reactions in Tropical Forest Soils

    NASA Astrophysics Data System (ADS)

    Lohse, K. A.

    2003-12-01

    Anthropogenic nitrogen (N) inputs may alter tropical soil buffering and exchange reactions that have important implications for nutrient cycling, forest productivity, and downstream ecosystems. In contrast to relatively young temperate soils that are typically buffered from N inputs by base cation reactions, aluminum reactions may serve to buffer highly weathered tropical soils and result in immediate increases in aluminum mobility and toxicity. Increased nitrate losses due to chronic N inputs may also deplete residual base cations in already weathered base cation-poor soils, further acidify soils, and thereby reduce nitrate mobility through pH-dependent anion exchange reactions. To test these hypotheses, I determined soil pH and cation and anion exchange capacity (CEC and AEC) and measured base cation and aluminum soil solution losses following first-time and long-term experimental N additions from two Hawaiian tropical forest soils, a 300 year old Andisol and a 4.1 million year old Oxisol. I found that elevated base cation losses accompanied increased nitrate losses after first time N additions to the young Andisol whereas immediate and large aluminum losses were associated with increased nitrate losses from the Oxisol. In the long-term, base cation and aluminum losses increased in proportion to nitrate losses. Long-term N additions at both sites resulted in significant declines in soil pH, decreased CEC and increased AEC. These results suggest that even chronic N inputs resulting in small but elevated nitrate losses may deplete residual base cations, increase mobility and toxicity of aluminum, and potentially lead to declines in forest productivity and acidification of downstream ecosystems. These findings also suggest that AEC may provide a long-term mechanism to delay nitrate losses in tropical forests with significant variable charge that are experiencing chronic anthropogenic N inputs.

  10. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    PubMed

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China.

  11. Selenium speciation in acidic environmental samples: application to acid rain-soil interaction at Mount Etna volcano.

    PubMed

    Floor, Geerke H; Iglesías, Mònica; Román-Ross, Gabriela; Corvini, Philippe F X; Lenz, Markus

    2011-09-01

    Speciation plays a crucial role in elemental mobility. However, trace level selenium (Se) speciation analyses in aqueous samples from acidic environments are hampered due to adsorption of the analytes (i.e. selenate, selenite) on precipitates. Such solid phases can form during pH adaptation up till now necessary for chromatographic separation. Thermodynamic calculations in this study predicted that a pH<4 is needed to prevent precipitation of Al and Fe phases. Therefore, a speciation method with a low pH eluent that matches the natural sample pH of acid rain-soil interaction samples from Etna volcano was developed. With a mobile phase containing 20mM ammonium citrate at pH 3, selenate and selenite could be separated in different acidic media (spiked water, rain, soil leachates) in <10 min with a LOQ of 0.2 μg L(-1) using (78)Se for detection. Applying this speciation analysis to study acid rain-soil interaction using synthetic rain based on H(2)SO(4) and soil samples collected at the flanks of Etna volcano demonstrated the dominance of selenate over selenite in leachates from samples collected close to the volcanic craters. This suggests that competitive behavior with sulfate present in acid rain might be a key factor in Se mobilization. The developed speciation method can significantly contribute to understand Se cycling in acidic, Al/Fe rich environments.

  12. Changes in hydraulic soil conductivity in the walls of zoogenic macropores due to the soil compaction

    NASA Astrophysics Data System (ADS)

    Pelíšek, Igor

    2015-04-01

    This study focuses on assessement of the hydric functions and effectiveness of the preferential zoogenic routes (preferentially lumbricid burrows), with primary focus on the hydric functions and parameters of individual vertical tubular macropores and on the analysis of selected possible detailed effects on these functions. The effect of earthworms (Lumbricidae) on the physical soil properties is notable. During burrowing, earthworms press the material in the vicinity of the hollowed burrows. Several variants of the relationship between the macropores and the soil compaction, permeability and erodibility were verified. Both measurements in the field and laboratory tests of intact collected samples and engineered samples were performed. With regard to preferential focus on the hydraulic processes in gravity macropores, to the limits of the instrumentation and the size of individual earthworms in agricultural soils in the Czech Republic, we assessed the processes in the macropores with diameter of ca 5 mm or larger. In some cases, saturated hydraulic conductivity of zoogenic macropore walls was reduced in order of tens of percent compared with hydraulic conductivity of soil matrix, and the increase of bulk density of soil in the macropore vicinity achieved 25%. The effect of repeated rise and water level stagnation (repeated macropore washing during multiple wetting cycles) was tested. Investigation of water erosion of macropores was limited by adjustable flow, vessel capacity and pump capacity of the accurate continuous infiltrometer. Investigation of the water inlet from above gave more data on the washed-off material in the selected time intervals. Analysis of water rise from below and macropore sealing provided one cumulative data for each testing period.

  13. Soil Bacteria Take Up D-Amino Acids, Protect Plants

    NASA Astrophysics Data System (ADS)

    Sun, H. J.; Zhang, G.

    2011-12-01

    Recently, many groups reported D-amino acid uptake by plant roots, raising the question of whether soil D-amino acids represent a source of nitrogen or a source of toxicity. The discussion needs to be placed in the context of competition with rhizosphere bacteria. To provide this context, we followed the concentrations of D- and L-enantiomers of alanine, glutamic acid, aspartic acid, and leucine after they were added to soils in the laboratory. In all cases, the uptake of L-enantiomer began immediately and proceeded rapidly until exhausted. In contrast, the uptake of D-enantiomer required induction: an initial period of inactivity followed by rapid consumption comparable in rate to L-enantiomer. The induced nature of the D activity was confirmed by the addition of rifampicin, an mRNA synthesis inhibitor. Preventing the synthesis of new enzymes abolished soil flora's ability to consume D-amino acids, but not L-amino acids. These results suggest that inducible special racemase enzymes, which can convert D-amino acids back to their native L-forms, are widespread among soil microorganisms. This finding does not rule out the possibility that some plants may out-compete microorganisms and be able to access D-amino acids. It does suggest, however, that rhizosphere bacteria can shield plants from the toxic effect of D-amino acids.

  14. Impact of acid effluent from Kawah Ijen crater lake on irrigated agricultural soils: Soil chemical processes and plant uptake

    NASA Astrophysics Data System (ADS)

    van Rotterdam-Los, A. M. D.; Heikens, A.; Vriend, S. P.; van Bergen, M. J.; van Gaans, P. F. M.

    2008-12-01

    Volcanogenic contamination of irrigation water, caused by effluent from the hyperacid Ijen crater lake, has severely affected the properties of agricultural soils in East Java, Indonesia. From a comparison of acidified topsoil with subsoil and with top- and subsoil in a reference area, we identified processes responsible for changes in soil and soil solution chemistry induced by acid irrigation water, with emphasis on the nutrients Ca, Mg, Fe, and Mn, and on Al, which may become phytotoxic under acid conditions in soils. Compositional data for bulk soil composition and selective extractions with 1 M KCl and 0.2 M acid ammonium oxalate are used in a mass balance approach to specify element fluxes, including uptake by rice plants. The results show that input via irrigation water has produced an increase in the total aluminum content in the affected topsoil, which is of the same order of magnitude as the increase in labile Al. High bioavailability of Al, as reflected by concentrations in KCl extracts, is consistent with elevated concentrations observed in rice plants. In contrast, and despite the high input via irrigation water, Ca and Mg concentrations have decreased in all measured soil fractions through dissolution of amorphous phases and minerals, and through competition of Al for adsorption sites on the exchange complex and plant roots. Strong leaching is also evident for Fe and especially Mn. In terms of the overall mass balance of the topsoil, plant uptake of Al, Ca, Fe, Mg and Mn is negligible. If the use of acid irrigation would be stopped and the soil pH were to increase to values above 4.5, the observed phytotoxicity of Al will be halted. However, crops may then become fully dependent on the input from irrigation water or fertilizer for essential elements, due to the previous removal from the topsoil through leaching.

  15. Arsenic removal from contaminated soil using phosphoric acid and phosphate.

    PubMed

    Zeng, Min; Liao, Bohan; Lei, Ming; Zhang, Yong; Zeng, Qingru; Ouyang, Bin

    2008-01-01

    Laboratory batch experiments were conducted to study arsenic (As) removal from a naturally contaminated soil using phosphoric acid (H3PO4) and potassium dihydrogen phosphate (KH2PO4). Both H3PO4 and KH2PO4 proved to reduce toxicity of the soil in terms of soil As content, attaining more than 20% As removal at a concentration of 200 mmol/L. At the same time, acidification of soil and dissolution of soil components (Ca, Mg, and Si) resulted from using these two extractants, especially H3PO4. The effectiveness of these two extractants could be attributed to the replacement of As by phosphate ions (PO4(3-)). The function of H3PO4 as an acid to dissolve soil components had little effects on As removal. KH2PO4 almost removed as much As as H3PO4, but it did not result in serious damage to soils, indicating that it was a more promising extractant. The results of a kinetic study showed that As removal reached equilibrium after incubation for 360 min, but dissolution of soil components, especially Mg and Ca, was very rapid. Therefore dissolution of soil components would be inevitable if As was further removed. Elovich model best described the kinetic data of As removal among the four models used in the kinetic study.

  16. Response of soil respiration to acid rain in forests of different maturity in southern China.

    PubMed

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types.

  17. Response of Soil Respiration to Acid Rain in Forests of Different Maturity in Southern China

    PubMed Central

    Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

    The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types. PMID:23626790

  18. Effect of selected soil conditioners on soil properties, erosion, runoff, and rye growth in nonfertile acid soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Construction operations result in highly disturbed soil, vulnerable to erosion and excess runoff and sediment loads. Limited information exists about effects of erosion mitigation practices on soil and runoff properties in low fertility acidic sites. The current study evaluates the use of polyacry...

  19. Slope Evolution by Stochastic Soil Production and Transport due to Biota

    NASA Astrophysics Data System (ADS)

    Dietrich, W. E.; Bellugi, D.

    2006-05-01

    To explore the role of variability in prediction of landscape form and evolution we need transport expressions that explicitly account for mechanisms linking a process to a stochastic driver or variable state. Recent work has begun the important task of exploring how stochastic rainfall events (rather than steady runoff) may affect landscape development. Another source of variability, bedrock characteristics, has long been discussed and noted, but predictions, using testable mechanistic expressions of processes, of how, say, bedrock fractures direct streams, or lithology determines hillslope gradients are lacking. A third source of stochasticity is the action of biota, and, here, even less is known. For hillslope processes, the role of biota is swept into parameters that set rates or controls strength or resistance in physical transport laws. While these parameters can be determined from field studies, they are usually evaluated for geomorphically significant periods in which the stochastic nature of biotic activity is ignored. Some aspects of stochasticity due to periodic fires have been explored. On hillslopes, rates of soil production from bedrock is often treated as an inverse function of soil depth, with the explanation being that biotic disruption of underlying weathered bedrock is less likely the thicker the soil. Transport downslope is modeled with linear and non-linear slope dependent expressions, with the rate constant parameters often assumed to be driven by dilational activity of biota in the soil. Here we explore the evolution of soil thickness and hillslope form caused by stochastic soil production and transport due to tree throw. For soil production the average recurrence interval of production is specified, and production occurrence at any cell is an independent random event at each time step. The amount of bedrock converted to soil at a production event is specified by the empirical soil production function. All disrupted bedrock and overlying soil

  20. Biochar impacts soil microbial community composition and nitrogen cycling in an acidic soil planted with rape.

    PubMed

    Xu, Hui-Juan; Wang, Xiao-Hui; Li, Hu; Yao, Huai-Ying; Su, Jian-Qiang; Zhu, Yong-Guan

    2014-08-19

    Biochar has been suggested to improve acidic soils and to mitigate greenhouse gas emissions. However, little has been done on the role of biochar in ameliorating acidified soils induced by overuse of nitrogen fertilizers. In this study, we designed a pot trial with an acidic soil (pH 4.48) in a greenhouse to study the interconnections between microbial community, soil chemical property changes, and N2O emissions after biochar application. The results showed that biochar increased plant growth, soil pH, total carbon, total nitrogen, C/N ratio, and soil cation exchange capacity. The results of high-throughput sequencing showed that biochar application increased α-diversity significantly and changed the relative abundances of some microbes that are related with carbon and nitrogen cycling at the family level. Biochar amendment stimulated both nitrification and denitrification processes, while reducing N2O emissions overall. Results of redundancy analysis indicated biochar could shift the soil microbial community by changing soil chemical properties, which modulate N-cycling processes and soil N2O emissions. The significantly increased nosZ transcription suggests that biochar decreased soil N2O emissions by enhancing its further reduction to N2.

  1. A modified acid digestion procedure for extraction of tungsten from soil.

    PubMed

    Bednar, A J; Jones, W T; Chappell, M A; Johnson, D R; Ringelberg, D B

    2010-01-15

    Interest in tungsten occurrence and geochemistry is increasing due to increased use of tungsten compounds and its unknown biochemical effects. Tungsten has a complex geochemistry, existing in most environmental matrices as the soluble and mobile tungstate anion, as well as poly- and heteropolytungstates. Because the geochemistry of tungsten is substantially different than most trace metals, including the formation of insoluble species under acidic conditions, it is not extracted from soil matrices using standard acid digestion procedures. Therefore, the current work describes a modification to a commonly used acid digestion procedure to facilitate quantification of tungsten in soil matrices. Traditional soil digestion procedures, using nitric and hydrochloric acids with hydrogen peroxide yield <1 up to 50% recovery on soil matrix spike samples, whereas the modified method reported here, which includes the addition of phosphoric acid, yields spike recoveries in the 76-98% range. Comparison of the standard and modified digestion procedures on National Institute of Standards and Technology Standard Reference Materials yielded significantly improved tungsten recoveries for the phosphoric acid modified method. The modified method also produces comparable results for other acid extractable metals as the standard methods, and therefore can be used simultaneously for tungsten and other metals of interest.

  2. Studies of the compositions of humic acids from Amazonian Dark Earth soils.

    PubMed

    Novotny, Etelvino H; deAzevedo, Eduardo R; Bonagamba, Tito J; Cunha, Tony J F; Madari, Beáta E; de M Benites, Vinícius; Hayes, Michael H B

    2007-01-15

    The compositions of humic acids (HAs) isolated from cultivated and forested "Terra Preta de Indio" or Amazonian Dark Earth soils (anthropogenic soils) were compared with those from adjacent non-anthropogenic soils (control soils) using elemental and thermogravimetric analyses, and a variety of solid-state nuclear magnetic resonance techniques. The thermogravimetric index, which indicates the molecular thermal resistance, was greater for the anthropogenic soils than for the control soils suggesting polycyclic aromatic components in the former. The cultivated anthropogenic soils were more enriched in C and depleted in H than the anthropogenic soils under forest, as the result of the selective degradation of aliphatic structures and the possible enrichment of H-deficient condensed aromatic structures. The combination of variable amplitude cross-polarization (VACP) and chemical shift anisotropy with total suppression of spinning sidebands experiments with composite pi pulses could be used to quantify the aromaticity of the HAs from the anthropogenic soils. From principal component analysis, using the VACP spectra, it was possible to separate the different constituents of the HAs, such as the carboxylated aromatic structures, from the anthropogenic soils and plant derived compounds. The data show that the HAs from anthropogenic soils have high contents of aryl and ionisable oxygenated functional groups, and the major functionalities from adjacent control soils are oxygenated functional groups from labile structures (carbohydrates, peptides, and with evidence for lignin structures). The anthropogenic soils HAs can be considered to be more recalcitrant, and with more stable reactive functional groups which may, in part, explain their more sustainable fertility due to the organic matter contribution to the soil cation exchange capacity.

  3. Amelioration of acidic soil using various renewable waste resources.

    PubMed

    Moon, Deok Hyun; Chang, Yoon-Young; Ok, Yong Sik; Cheong, Kyung Hoon; Koutsospyros, Agamemnon; Park, Jeong-Hun

    2014-01-01

    In this study, improvement of acidic soil with respect to soil pH and exchangeable cations was attempted for sample with an initial pH of approximately 5. Acidic soil was amended with various waste resources in the range of 1 to 5 wt.% including waste oyster shells (WOS), calcined oyster shells (COS), Class C fly ash (FA), and cement kiln dust (CKD) to improve soil pH and exchangeable cations. Upon treatment, the soil pH was monitored for periods up to 3 months. The exchangeable cations were measured after 1 month of curing. After a curing period of 1 month, a maize growth experiment was conducted with selected-treated samples to evaluate the effectiveness of treatment. The treatment results indicate that in order to increase the soil pH to a value of 7, 1 wt.% of WOS, 3 wt.% of FA, and 1 wt.% of CKD are required. In the case of COS, 1 wt.% was more than enough to increase the soil pH value to 7 because of COS's strong alkalinity. Moreover, the soil pH increases after a curing period of 7 days and remains virtually unchanged thereafter up to 1 month of curing. Upon treatment, the summation of cations (Ca, Mg, K, and Na) significantly increased. The growth of maize is superior in the treated samples rather than the untreated one, indicating that the amelioration of acidic soil is beneficial to plant growth, since soil pH was improved and nutrients were replenished.

  4. Assessment of natural and calcined starfish for the amelioration of acidic soil.

    PubMed

    Moon, Deok Hyun; Yang, Jae E; Cheong, Kyung Hoon; Koutsospyros, Agamemnon; Park, Jeong-Hun; Lim, Kyoung Jae; Kim, Sung Chul; Kim, Rog-Young; Ok, Yong Sik

    2014-01-01

    Quality improvement of acidic soil (with an initial pH of approximately 4.5) with respect to soil pH, exchangeable cations, organic matter content, and maize growth was attempted using natural (NSF) and calcined starfish (CSF). Acidic soil was amended with NSF and CSF in the range of 1 to 10 wt.% to improve soil pH, organic matter content, and exchangeable cations. Following the treatment, the soil pH was monitored for periods up to 3 months. The exchangeable cations were measured after 1 month of curing. After a curing period of 1 month, the maize growth experiment was performed with selected treated samples to evaluate the effectiveness of the treatment. The results show that 1 wt.% of NSF and CSF (700 and 900 °C) were required to increase the soil pH to a value higher than 7. In the case of CSF (900 °C), 1 wt.% was sufficient to increase the soil pH value to 9 due to the strong alkalinity in the treatment. No significant changes in soil pHs were observed after 7 days of curing and up to 3 months of curing. Upon treatment, the cation exchange capacity values significantly increased as compared to the untreated samples. The organic content of the samples increased upon NSF treatment, but it remains virtually unchanged upon CSF treatment. Maize growth was greater in the treated samples rather than the untreated samples, except for the samples treated with 1 and 3 wt.% CSF (900 °C), where maize growth was limited due to strong alkalinity. This indicates that the amelioration of acidic soil using natural and calcined starfish is beneficial for plant growth as long as the application rate does not produce alkaline conditions outside the optimal pH range for maize growth.

  5. Nitrogen saturation, soil acidification, and ecological effects in a subtropical pine forest on acid soil in southwest China

    NASA Astrophysics Data System (ADS)

    Huang, Yongmei; Kang, Ronghua; Mulder, Jan; Zhang, Ting; Duan, Lei

    2015-11-01

    Elevated anthropogenic nitrogen (N) deposition has caused nitrate (NO3-) leaching, an indication of N saturation, in several temperate and boreal forests across the Northern Hemisphere. So far, the occurrence of N saturation in subtropical forests and its effects on the chemistry of the typically highly weathered soils, forest growth, and biodiversity have received little attention. Here we investigated N saturation and the effects of chronically high N inputs on soil and vegetation in a typical, subtropical Masson pine (Pinus massoniana) forest at Tieshanping, southwest China. Seven years of N flux data obtained in ambient conditions and in response to field manipulation, including a doubling of N input either as ammonium nitrate (NH4NO3) or as sodium nitrate (NaNO3) solution, resulted in a unique set of N balance data. Our data showed extreme N saturation with near-quantitative leaching of NO3-, by far the dominant form of dissolved inorganic N in soil water. Even after 7 years, NH4+, added as NH4NO3, was nearly fully converted to NO3-, thus giving rise to a major acid input into the soil. Despite the large acid input, the decrease in soil pH was insignificant, due to pH buffering caused by Al3+ mobilization and enhanced SO42- adsorption. In response to the NH4NO3-induced increase in soil acidification and N availability, ground vegetation showed significant reduction of abundance and diversity, while Masson pine growth further declined. By contrast, addition of NaNO3 did not cause soil acidification. The comparison of NH4NO3 treatment and NaNO3 treatment indicated that pine growth decline was mainly attributed to acidification-induced nutrient imbalance, while the loss in abundance of major ground species was the combining effect of N saturation and acidification. Therefore, N emission control is of primary importance to curb further acidification and eutrophication of forest soils in much of subtropical south China.

  6. Rhizosheaths on wheat grown in acid soils: phosphorus acquisition efficiency and genetic control

    PubMed Central

    James, Richard A.; Weligama, Chandrakumara; Verbyla, Klara; Ryan, Peter R.; Rebetzke, Gregory J.; Rattey, Allan; Richardson, Alan E.; Delhaize, Emmanuel

    2016-01-01

    Rhizosheaths comprise soil bound to roots, and in wheat (Triticum aestivum L.) rhizosheath size correlates with root hair length. The aims of this study were to determine the effect that a large rhizosheath has on the phosphorus (P) acquisition by wheat and to investigate the genetic control of rhizosheath size in wheat grown on acid soil. Near-isogenic wheat lines differing in rhizosheath size were evaluated on two acid soils. The soils were fertilized with mineral nutrients and included treatments with either low or high P. The same soils were treated with CaCO3 to raise the pH and detoxify Al3+. Genotypic differences in rhizosheath size were apparent only when soil pH was low and Al3+ was present. On acid soils, a large rhizosheath increased shoot biomass compared with a small rhizosheath regardless of P supply. At low P supply, increased shoot biomass could be attributed to a greater uptake of soil P, but at high P supply the increased biomass was due to some other factor. Generation means analysis indicated that rhizosheath size on acid soil was controlled by multiple, additive loci. Subsequently, a quantitative trait loci (QTL) analysis of an F6 population of recombinant inbred lines identified five major loci contributing to the phenotype together accounting for over 60% of the total genetic variance. One locus on chromosome 1D accounted for 34% of the genotypic variation. Genetic control of rhizosheath size appears to be relatively simple and markers based on the QTL provide valuable tools for marker assisted breeding. PMID:26873980

  7. Burns due to acid assaults in Bogotá, Colombia.

    PubMed

    Guerrero, Linda

    2013-08-01

    Acid burns are not very frequent, occupying between 3% and maximum 14% of all etiologies. They mostly occur at home or at work, however there has been an increase in publications outlining chemical burns where aggression is the cause of this burn. There is a different epidemiological profile between developed countries and developing ones. It seems an ongoing upsurge is occurring in the number of registered attacks within developing countries in recent years. A cross sectional retrospective review of attacks by acid was done in Bogota, Colombia from 1995 to the first trimester 2012. A cumulative number of 35 burn patients were registered during the study period. It is found that the main target, almost the unique target, of this attack are young women belonging to low socioeconomic status with low education degree and high dependence on her partner. The patient's age mean was 22.7 years, ranging from 13 to 41 years. The physical and psychological scars were very severe.

  8. Phosphoric acid, nitric acid, and hydrogen peroxide digestion of soil and plant materials for selenium determination

    SciTech Connect

    Dong, A.; Rendig, V.V.; Burau, R.G.; Besga, G.S.

    1987-11-15

    A mixture of phosphoric acid, nitric acid, and hydrogen peroxide has been proposed as an alternative to the use of the nitric/perchloric acid mixture to digest biological fluids to determine their selenium (Se) content. The purpose of the studies reported here was to test the applicability of this digestion method for the determination of Se in soil and plant materials.

  9. Soil water samplers in ion balance studies on acidic forest soils

    SciTech Connect

    Rasmussen, L.; Joergensen, P.; Kruse, S.

    1986-04-01

    During the last years an increasing consciousness has appeared of the injurious effects of acid rain on the forest ecosystems both in Europe and North America. At several localities ion balance studies have been implemented in order to evaluate the impact of the atmospheric deposition of acidic substances and heavy metals on the forest ecosystem. In many localities the leaching of material to the ground water or output from the ecosystem has to be determined by means of tensiometer measurements and soil water sampling. Many different soil water samplers are available on the market and they show useful applicability under the given circumstances. But in many cases soil water samples taken with different equipment give incommensurable results leading to differing explanations of the effects of acid precipitation on elements and their cycling in the ecosystem. The purpose of the present study is twofold. Firstly, the sorption characteristics of different types of soil water samplers are examined under acidic soil conditions both by installation in the field and by laboratory experiments. Secondly, a new method is introduced for current and constant soil water sampling under varying soil suctions in the unsaturated zone.

  10. Microbiological aspects of determination of trichloroacetic acid in soil.

    PubMed

    Matucha, M; Gryndler, M; Uhlírová, H; Fuksová, K; Rohlenová, J; Forczek, S T; Schröder, P

    2004-01-01

    Soils have been shown to possess a strong microbial trichloroacetic acid (TCA)-degrading activity. High TCA-degradation rate was also observed during soil extraction with water. For correct measurements of TCA levels in soil all TCA-degrading activities have to be inhibited immediately after sampling before analysis. We used rapid freezing of soil samples (optimally in liquid nitrogen) with subsequent storage and slow thawing before analysis as an efficient technique for suppressing the degradation. Frozen soil samples stored overnight at -20 degrees C and then thawed slowly exhibited very low residual TCA-degrading activity for several hours. Omitting the above procedure could lead to the confusing differences between the TCA levels previously reported in the literature.

  11. Extractability of elements in sugar maple xylem along a gradient of soil acidity.

    PubMed

    Bilodeau Gauthier, Simon; Houle, Daniel; Gagnon, Christian; Côté, Benoît; Messier, Christian

    2008-01-01

    Dendrochemistry has been used for the historical dating of pollution. Its reliability is questionable due primarily to the radial mobility of elements in sapwood. In the present study, the extractability of seven elements was characterized to assess their suitability for the monitoring of environmental conditions. Nine mature sugar maple trees (Acer saccharum Marsh.), a wide-ranging species in eastern North America that has suffered decline in past decades, were sampled in three Quebec watersheds along a soil acidity gradient. Five-year groups of annual tree rings were treated by sequential chemical extractions using extractants of varying strength (deionized H2O, 0.05 M HCl, and concentrated HNO(3)) to selectively solubilize the elements into three fractions (water-soluble, acid-soluble, and residual). Monovalent K; divalent Ba, Ca, Cd, Mg, Mn; and trivalent Al cations were found mostly in the water-soluble, acid-soluble, and residual fractions, respectively. Forms more likely to be mobile within the tree (water-soluble and acid-soluble) do not seem to be suitable for temporal monitoring because of potential lateral redistribution in sapwood rings. However, certain elements (Cd, Mn) were responsive to current soil acidity and could be used in spatial variation monitoring. Extractability of Al varied according to soil acidity; at less acidic sites, up to 90% of Al was contained in the residual form, whereas on very acidic soils, as much as 45% was found in the water-soluble and acid-soluble fractions. Sequential extractions can be useful for determining specific forms of metals as key indicators of soil acidification.

  12. Evolution of hydrological pathways in engineered hillslopes due to soil and vegetation development

    NASA Astrophysics Data System (ADS)

    Appels, Willemijn M.; Ireson, Andrew M.; McDonnell, Jeffrey J.; Barbour, S. Lee

    2015-04-01

    The structure and hydraulic properties of soils and bedrock within a hillslope combined with the timing and rates of water availability control the partitioning of precipitation into vertical and lateral flowpaths. In natural hillslope sites, heterogeneity in both soil texture and structure are the result of long-term landscape evolution processes and consequently can be assumed to be static relative to the timescale of rainfall-runoff processes. However; engineered hillslopes, constructed commonly as reclamation covers overlying mine waste, have been observed to undergo rapid changes in hydraulic properties over relatively short timescales (i.e. 3-5 years) as a result of weathering (e.g. freeze-thaw and wet-dry cycles) and vegetation growth (e.g. increasing rooting depth and density). Rainfall-runoff responses on such hillslopes would therefore not only be expected to reflect seasonal dynamics, but also the evolution of the system from a relatively homogeneous initial condition to a system with increasing heterogeneity of soil texture and structure. We present results of a combined field and modeling study of three prototype soil covers on a saline-sodic shale overburden dump at the Syncrude Canada Ltd. Mildred Lake mine, north of Fort McMurray, Canada. Since their construction in 1999, soil properties, hydrological response to atmospheric and vegetative demands, and vegetation properties have been extensively monitored. The three covers have undergone substantial evolution due to freeze-thaw processes and aggrading vegetation. In this work, we quantify hydrological processes in the reclamation covers, focusing on inter- and intra-annual patterns. To this purpose we analyzed the long-term hydrometric data with field sampling of the distribution of salts and the stable isotopes of water within soil water and subsurface flow in the base of the cover. We use a 2D Hydrus model to explore the co-evolution of soil and vegetation and quantify its effect on flow

  13. Effective gamma-ray doses due to natural radiation from soils of southeastern Brazil

    SciTech Connect

    Silveira, M. A. G.; Moreira, R. H.; Bellini, B. S.; Medina, N. H.; Aguiar, V. A. P.

    2010-08-04

    We have used gamma-ray spectrometry to study the distribution of natural radiation from soils of southeastern Brazil: Billings reservoir, Sao Bernardo do Campo Parks, Diadema Parks, Interlagos region, Sao Paulo, and soil from Sao Paulo and Rio de Janeiro beaches. In most of the regions studied we have found that the dose due the external exposure to gamma-rays, proceeding from natural terrestrial elements, are between the values 0.3 and 0.6 mSv/year, established by the United Nations Scientific Committee on the Effects of Atomic Radiation.

  14. APPLICABILITY OF A ACCUMULATED DAMAGE PARAMETER METHOD ON SOIL LIQUEFACTION DUE TOSEVERAL EARTHQUAKES

    NASA Astrophysics Data System (ADS)

    Izawa, Jun; Tanoue, Kazuya; Murono, Yoshitaka

    Severe soil liquefaction due to long duration earthquake with low acceleration occurred at Tokyo Bay area in the 2011 off the Pacific coast of Tohoku Earthquake. This phenomenon clearly shows that soil liquefaction is affected by properties of input waves. This paper describes effect of wave properties of earthquake on liquefaction using Effective Stress analysis with some earthquakes. Analytical result showedthat almost the same pore water pressure was observed due to both long durationearthquake with max acceleration of 150Gal and typical inland active fault earthquake with 891Gal. Additionally, lique-faction potentials for each earthquake were evaluated by simple judgment with accumulated damage parameter, which is used for design of railway structuresin Japan. As a result, it was found that accurate liquefaction resistance on large cyclic area is necessaryto evaluate liquefaction potential due to long duration earthquake with low acceleration with simple judgment with accumulated damage parameter.

  15. A reexamination of amino acids in lunar soil

    NASA Astrophysics Data System (ADS)

    Brinton, K. L. F.; Bada, J. L.; Arnold, J. R.

    1993-03-01

    Amino acids in lunar soils provide an important indicator of the level of prebiotic organic compounds on the moon. The results provide insight into the chemistry of amino acid precursors, and furthermore, given the flux of carbonaceous material to the moon, we can evaluate the survival of organics upon impact. The amino acid contents of both hydrolyzed and unhydrolyzed hot-water extracts of Apollo 17 lunar soil were determined using ophthaldialdehyde/N-acetyl cysteine (OPA/NAC) derivatization followed by HPLC analysis. Previous studies of lunar amino acids were inconclusive, as the technique used (derivatization with ninhydrin followed by HPLC analysis) was unable to discriminate between cosmogenic amino acids and terrestrial contaminants. Cosmogenic amino acids are racemic, and many of the amino acids found in carbonaceous meteorites such as Murchison, i.e., alpha-amino-i-butyric acid (aib), are extremely rare on Earth. The ninhydrin method does not distinguish amino acid enantiomers, nor does it detect alpha-alkyl amino acids such as aib, whereas the OPA/NAC technique does both.

  16. A reexamination of amino acids in lunar soil

    NASA Technical Reports Server (NTRS)

    Brinton, K. L. F.; Bada, J. L.; Arnold, J. R.

    1993-01-01

    Amino acids in lunar soils provide an important indicator of the level of prebiotic organic compounds on the moon. The results provide insight into the chemistry of amino acid precursors, and furthermore, given the flux of carbonaceous material to the moon, we can evaluate the survival of organics upon impact. The amino acid contents of both hydrolyzed and unhydrolyzed hot-water extracts of Apollo 17 lunar soil were determined using ophthaldialdehyde/N-acetyl cysteine (OPA/NAC) derivatization followed by HPLC analysis. Previous studies of lunar amino acids were inconclusive, as the technique used (derivatization with ninhydrin followed by HPLC analysis) was unable to discriminate between cosmogenic amino acids and terrestrial contaminants. Cosmogenic amino acids are racemic, and many of the amino acids found in carbonaceous meteorites such as Murchison, i.e., alpha-amino-i-butyric acid (aib), are extremely rare on Earth. The ninhydrin method does not distinguish amino acid enantiomers, nor does it detect alpha-alkyl amino acids such as aib, whereas the OPA/NAC technique does both.

  17. [Effects of thiourea on pH and availability of metal ions in acid red soil].

    PubMed

    Yang, Bo; Wang, Wen; Zeng, Qing-Ru; Zhou, Xi-Hong

    2014-03-01

    Through the simulation research, the effects of application of thiourea and urea on pH and availability of metal ions in acid red soil were studied, and the results showed that after applying urea, the soil pH increased in the first experimental stage and then reduced gradually to a low level, however, decreased trends of soil pH values were inhibited by the application of thiourea, especially when the concentration of thiourea reached to 5.0 mmol x kg(-1) dry soil, the soil pH was stable at high level, which exceeded to 6.0. It proved that the application of thiourea could inhibit the soil acidification due to urea application. After applying urea with different concentrations of thiourea, the available contents of Zn and Al decreased with the increasing concentration of thiourea, nevertheless, when the concentration of thiourea reached to 5.0 mmol x kg(-1), the available content of Mn was stable at high level which was over 110 mg x kg(-1). In addition, the results showed a highly significant negative correlation between the soil pH and the available content of Cu, Zn and Al, but for Mn, no discipline was found between the soil pH and the availability after applying thiourea. Moreover, the soil pH became higher after applying urea with thiourea compared to add urea only, which led to the decreasing of available content of Al, and it was benefited for the control of the phytotoxic effect of Al. The available content of Mn in the soil not only depended on soil pH but also the content of thiourea due to its redox and complexing reaction with Mn.

  18. N{sub 2}O production pathways in the subtropical acid forest soils in China

    SciTech Connect

    Zhang Jinbo; Cai Zucong; Zhu Tongbin

    2011-07-15

    To date, N{sub 2}O production pathways are poorly understood in the humid subtropical and tropical forest soils. A {sup 15}N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N{sub 2}O production in four subtropical acid forest soils (pH<4.5) in China. The results showed that denitrification was the main source of N{sub 2}O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N{sub 2}O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N{sub 2}O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N{sub 2}O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N{sub 2}O product ratios from nitrification. The ratio of N{sub 2}O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: {yields} We studied N{sub 2}O production pathways in subtropical acid forest soil under aerobic conditions. {yields} Denitrification was the main source of N{sub 2}O production in subtropical acid forest soils. {yields} Heterotrophic nitrification accounted for 27.3%-41.8% of N{sub 2}O production. {yields} While, contribution of autotrophic nitrification to N{sub 2}O production was little. {yields} Ratios of N{sub 2}O-N emission from nitrification were higher than those in most previous references.

  19. Acid-activated biochar increased sulfamethazine retention in soils.

    PubMed

    Vithanage, Meththika; Rajapaksha, Anushka Upamali; Zhang, Ming; Thiele-Bruhn, Sören; Lee, Sang Soo; Ok, Yong Sik

    2015-02-01

    Sulfamethazine (SMZ) is an ionizable and highly mobile antibiotic which is frequently found in soil and water environments. We investigated the sorption of SMZ onto soils amended with biochars (BCs) at varying pH and contact time. Invasive plants were pyrolyzed at 700 °C and were further activated with 30 % sulfuric (SBBC) and oxalic (OBBC) acids. The sorption rate of SMZ onto SBBC and OBBC was pronouncedly pH dependent and was decreased significantly when the values of soil pH increased from 3 to 5. Modeled effective sorption coefficients (K D,eff) values indicated excellent sorption on SBBC-treated loamy sand and sandy loam soils for 229 and 183 L/kg, respectively. On the other hand, the low sorption values were determined for OBBC- and BBC700-treated loamy sand and sandy loam soils. Kinetic modeling demonstrated that the pseudo second order model was the best followed by intra-particle diffusion and the Elovich model, indicating that multiple processes govern SMZ sorption. These findings were also supported by sorption edge experiments based on BC characteristics. Chemisorption onto protonated and ligand containing functional groups of the BC surface, and diffusion in macro-, meso-, and micro-pores of the acid-activated BCs are the proposed mechanisms of SMZ retention in soils. Calculated and experimental q e (amount adsorbed per kg of the adsorbent at equilibrium) values were well fitted to the pseudo second order model, and the predicted maximum equilibrium concentration of SBBC for loamy sand soils was 182 mg/kg. Overall, SBBC represents a suitable soil amendment because of its high sorption rate of SMZ in soils.

  20. Increasing organic carbon stocks in Swedish agricultural soils due to unexpected socio-economic drivers

    NASA Astrophysics Data System (ADS)

    Poeplau, Christopher; Bolinder, Martin A.; Eriksson, Jan O.; Lundblad, Mattias; Kätterer, Thomas

    2015-04-01

    Management changes can induce significant alterations of soil organic carbon (SOC) stocks. Including trends in SOC within a certain land-use category can thus strongly influence the annual national inventory reports for greenhouse gas emissions. In 2013, the European Union has therefore decided that all member states shall report the evolvement of SOC within agricultural soils to increase the incentives to mitigate climate change by improving the management of those soils. Here, we present the country and county-wise SOC trends in Swedish agricultural mineral soils on the basis of three soil inventories conducted between 1988 and 2013. In the past two decades, the average topsoil (0-20 cm) SOC content of the whole country increased from 2.48% to 2.67% representing a relative change of 7.7% or 0.38% yr-1. This is in contrast to trends observed in neighboring countries such as Norway and Finland. We attributed this positive SOC trend to the increasing cultivation of leys throughout the country. Indeed, the below-ground carbon input of perennial grasses is up to fourfold as compared to cereals, which leads to a significant soil carbon sequestration potential under cropping systems with ley. The increase in ley proportion was significantly correlated to the increase in horse population in each county (R2=0.71), which has more than doubled in the past three decades. Due to subsidies introduced in the early 1990s, the area as long-term set-aside land (mostly old leys) also contributed to an increase in leys. This discloses the strong impact of rather local socio-economic trends on soil carbon storage, which also need to be considered in larger-scale model applications. This database is used in the continuous validation process of the Swedish national system for reporting changes in SOC stocks.

  1. Estimating deformation due to soil liquefaction in Urayasu city, Japan using permanent scatterers

    NASA Astrophysics Data System (ADS)

    ElGharbawi, Tamer; Tamura, Masayuki

    2015-11-01

    In Japan, several cities endured severe damage due to soil liquefaction phenomenon, which was developed in association with the massive shaking of the 2011 Tohoku earthquake. Measuring soil liquefaction deformations was not an easy task, mainly because of the total loss of signal coherence in the affected regions. In this paper, we present our approach to estimate the deformations associated with soil liquefaction using interferometric synthetic aperture radar techniques. We use a stack of coseismic interferograms to identify the reliable pixels in the damaged areas using permanent scatterers technique. Then, we estimate and remove the preseismic mean velocity and DEM error components. Finally, we identify the liquefaction deformation component using least squares inversion and spatial phase filtering. We test the performance of the proposed approach using synthetic data, simulating the effects of soil liquefaction. The simulation results show a RMSE of the liquefaction deformation of 5.23 mm. After that, we estimate the deformation associated with soil liquefaction in Urayasu city, Japan, using ALOS-PALSAR data. The proposed approach allows a prompt estimation of the liquefaction deformation by utilizing the SAR images archives with only one postseismic SAR image.

  2. Limitations in the use of commercial humic acids in water and soil research

    USGS Publications Warehouse

    Malcolm, R.L.; MacCarthy, P.

    1986-01-01

    Seven samples of commercial "humic acids", purchased from five different suppliers, were studied, and their characteristics were compared with humic and fulvic acids isolated from streams, soils, peat, leonardite, and a dopplerite sample. Cross-polarization and magic-angle spinning 13C NMR spectroscopy clearly shows pronounced differences between the commercial materials and all other samples. Elemental and infrared spectroscopic data do not show such clear-cut differences but can be used as supportive evidence, with the 13C NMR data, to substantiate the above distinctions. As a result of these differences and due to the general lack of information relating to the source, method of isolation, or other pretreatment of the commercial materials, these commercial products are not considered to be appropriate for use as analogues of true soil and water humic substances, in experiments designed to evaluate the nature and reactivity of humic substances in natural waters and soils.

  3. Soil Studies: Applying Acid-Base Chemistry to Environmental Analysis.

    ERIC Educational Resources Information Center

    West, Donna M.; Sterling, Donna R.

    2001-01-01

    Laboratory activities for chemistry students focus attention on the use of acid-base chemistry to examine environmental conditions. After using standard laboratory procedures to analyze soil and rainwater samples, students use web-based resources to interpret their findings. Uses CBL probes and graphing calculators to gather and analyze data and…

  4. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste

    SciTech Connect

    Hamdi, Noureddine; Srasra, Ezzeddine

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Examined the hydraulic conductivity evolution as function of dry density of Tunisian clay soil. Black-Right-Pointing-Pointer Follow the hydraulic conductivity evolution at long-term of three clay materials using the waste solution (pH=2.7). Black-Right-Pointing-Pointer Determined how compaction affects the hydraulic conductivity of clay soils. Black-Right-Pointing-Pointer Analyzed the concentration of F and P and examined the retention of each soil. - Abstract: Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 Multiplication-Sign 10{sup -10}, 2.08 Multiplication-Sign 10{sup -9} and 6.8 Multiplication-Sign 10{sup -10} m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m{sup 3}). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH = 2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m{sup 3}) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

  5. Aldohexuronic Acid Catabolism by a Soil Aeromonas

    PubMed Central

    Farmer, J. J.; Eagon, R. G.

    1969-01-01

    Bacteria which utilize mannuronic acid as an energy source were isolated from nature. One of the organisms, identified as a member of the genus Aeromonas, used glucuronate, galacturonate, and mannuronate as the sole source of carbon and energy. Glucuronate- and galacturonate-grown resting cells oxidized both glucuronate and galacturonate rapidly, but mannuronate slowly. Mannuronate-grown cells oxidized all three rapidly, with the rate of mannuronate utilization somewhat lower. Cell-free extracts from glucuronate-, galacturonate-, and mannuronate-grown Aeromonas C11-2B contained glucuronate and galacturonate isomerases, fructuronate, tagaturonate, and mannuronate reductases, and mannonate and altronate dehydratases, with the exception of glucuronate-grown cells which lacked altronate dehydratase. Thus, the pathway for glucuronate and galacturonate catabolism for Aeromonas was identical to Escherichia coli. Glucuronate and galacturonate were isomerized to d-fructuronate and d-tagaturonate which were then reduced by reduced nicotinamide adenine dinucleotide to d-mannonate and d-altronate, respectively. The hexonic acids were dehydrated to 2-keto-3-deoxy gluconate which was phosphorylated by adenosine triphosphate to 2-keto-3-deoxy-6-phospho gluconate. The latter was then cleaved to pyruvate and glyceraldehyde-3-phosphate. Mannuronate was reduced directly to d-mannonate by a reduced nicotinamide adenine dinucleotide phosphate-linked oxidoreductase. d-Mannonate was then further broken down as in the glucuronate pathway. The mannuronate reducing enzyme, for which the name d-mannonate:nicotinamide adenine dinucleotide (phosphate) oxidoreductase (d-mannuronate-forming) was proposed, was shown to be distinct from altronate and mannoate oxidoreductases. This is the first report of a bacterial oxidoreductase which reduces an aldohexuronic acid to a hexonic acid. The enzyme should prove to be a useful analytical tool for determining mannuronate in the presence of other uronic

  6. Robust analysis of underivatized free amino acids in soil by hydrophilic interaction liquid chromatography coupled with electrospray tandem mass spectrometry.

    PubMed

    Gao, Jiajia; Helmus, Rick; Cerli, Chiara; Jansen, Boris; Wang, Xiang; Kalbitz, Karsten

    2016-06-03

    Amino acids are an important and highly dynamic fraction of organic N in soils and their determination in soil without derivatization is challenging due to the difficulties in separation and detection of trace amounts of these polar analytes. In the present work, we developed an analytical method to quantify 20 free amino acids in aqueous soil extracts without derivatization. The method employed hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) technique combined with a cation exchange solid phase extraction (SPE). Four stable isotope labelled amino acids were used as internal standards to improve the method performance. Good separation of 20 underivatized amino acids was achieved within 12min. The limit of detection (LODs) and limit of quantification (LOQs) were in the range of 13-384ngg(-1) and 43-1267ngg(-1) (dry soil basis), respectively. The results showed that overall recoveries with high precision were obtained for the extracted free amino acids from ten different soils. The overall recoveries of 18 amino acids were similar for the ten soils used, which differed substantially in organic C content and in other properties as soil texture and pH. For most of the amino acids, the average recoveries from soil extracts were between 74% and 117%, with the exception of Met (31%), Pro (52%) and Arg (68%). Variability was within acceptable limits (relative standard deviations were between 4% and 13%), with the exception of Met (relative standard deviation=90%) and Arg (relative standard deviation=53%). Thus the proposed method with high throughout and high analyte specificity shows great promise for consistent analysis of free amino acids extracted from soils and offers new horizons for the analysis of amino acids in terrestrial and aquatic ecosystem.

  7. Accelerated soil mineralization, nitrification, and revegetation of abandoned fields due to the removal of crop-soil phytotoxicity.

    PubMed

    Lodhi, M A

    1981-07-01

    In an abandoned corn field, clear-cutting of crop vegetation increased the productivity, species richness, and nonannuals in the following years after abandonment, as compared to the control plots from which crop vegetation was not removed. The increase in plant growth was apparently due to the elimination of allelopathic chemicals from the soil, which normally are released from the standing crop. Removal of vegetation also increased the soil mineralization of Ca(2+), Mg(2+), K(+), NH4 (+) and NO3 (-)-N. This situation encouraged species having higher mineral requirements to rapidly invade the fields in the successive years. Clear-cutting also increased the nitrification process by removing the inhibitors of nitrification. The number ofNitrosomonas was always significantly higher in the harvested plots as compared to unharvested plots. Phenolic phytotoxins were isolated from the crop residue and soil. Further, these phytotoxins were significantly higher in the unharvested crops as compared to clear-cut plots, in most samples. Whatever the direct or indirect additional explanation for increased biomass, nonannuals and richness in successive years, it is clear that the removal of standing crop has a definite influence.

  8. Ethylene limits abscisic acid- or soil drying-induced stomatal closure in aged wheat leaves.

    PubMed

    Chen, Lin; Dodd, Ian C; Davies, William J; Wilkinson, Sally

    2013-10-01

    The mechanism of age-induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA- or soil drying-induced stomatal closure of older leaves was partly restored by pretreating plants with 1-methylcyclopropene (1-MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C-2, which contains 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water-use efficiency.

  9. Organic amendments increase soil solution phosphate concentrations in an acid soil: A controlled environment study

    SciTech Connect

    Schefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, R.

    2008-04-15

    Soil acidification affects at least 4 million hectares of agricultural land in Victoria, Australia. Low soil pH can inhibit plant growth through increased soluble aluminum (Al) concentrations and decreased available phosphorus (P). The addition of organic amendments may increase P availability through competition for P binding sites, solubilization of poorly soluble P pools, and increased solution pH. The effect of two organic amendments (lignite and compost) on P solubility in an acid soil was determined through controlled environment (incubation) studies. Three days after the addition of lignite and compost, both treatments increased orthophosphate and total P measured in soil solution, with the compost treatments having the greatest positive effect. Increased incubation time (26 days) increased soil solution P concentrations in both untreated and amended soils, with the greatest effect seen in total P concentrations. The measured differences in solution P concentrations between the lignite- and compost-amended treatments were likely caused by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment with lignite or compost also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. Based on the results presented, it is proposed that the measured increase in soil solution P with amendment addition was likely caused by both chemical and biological processes, including biotic and abiotic P solubilization reactions, and the formation of soluble organic-metal complexes.

  10. Isotopically exchangeable Al in coastal lowland acid sulfate soils.

    PubMed

    Yvanes-Giuliani, Yliane A M; Fink, D; Rose, J; Waite, T David; Collins, Richard N

    2016-01-15

    Periodic discharges of high concentrations of aluminium (Al) causing fish kills and other adverse effects occur worldwide in waterways affected by coastal lowland acid sulfate soils (CLASS). The exchangeability - a metal's ability to readily transfer between the soil solid- and solution-phases - of Al in these soils is therefore of particular importance as it has implications for metal transport, plant availability and toxicity to living organisms. In the present study, the concentrations of isotopically exchangeable Al (E values) were measured in 27 CLASS and compared with common salt extractions (i.e. KCl and CuCl2) used to estimate exchangeable soil pools of Al. E values of Al were high in the soils, ranging from 357 to 3040 mg·kg(-1). Exchangeable concentrations estimated using 1 M KCl were consistently lower than measured E values, although a reasonable correlation was obtained between the two values (E=1.68×AlKCl, r(2)=0.66, n=25). The addition of a 0.2 M CuCl2 extraction step improved the 1:1 agreement between extractable and isotopically exchangeable Al concentrations, but lead to significant mobilisation of non-isotopically exchangeable Al in surficial 'organic-rich' CLASS having E values<1000 mg·kg(-1). It was concluded that currently used (i.e. 1 M KCl) methodology severely underestimates exchangeable Al and total actual acidity values in CLASS and should be corrected by a factor similar to the one determined here.

  11. Changes in soil pH across England and Wales in response to decreased acid deposition

    NASA Astrophysics Data System (ADS)

    Kirk, G. J. D.; Bellamy, P. H.

    2009-04-01

    In our recent analysis of data from the National Soil Inventory of England and Wales, we found widespread changes in soil pH across both countries between the two samplings of the Inventory. In general, soil pH increased - i.e. soils became less acid - under all land uses. The Inventory was first sampled in 1978-83 on a 5-km grid over the whole area. This yielded about 6,000 sites of which 5,662 could be sampled for soil. Roughly 40% of the sites were re-sampled at intervals from 12 to 25 years after the original sampling - in 1994/96 for agricultural land and in 2002/03 for non-agricultural. Exactly the same sampling and analytical protocols were used in the two samplings. In arable soils, the increase in pH was right across the range, whereas in grassland soils the main increase was at the acid end of the scale (pH < 5.5) with a small increase above pH 7. Some part of the change is likely to have been due to changes in land management. This includes better targeting of agricultural lime on acid soils; changes in nitrogen fertilizer use; deeper ploughing bringing up more calcareous subsoil on soils on calcareous materials; and so forth. However a major driver appears to have been decreased acid deposition to land. The total amounts of nitrogen compounds deposited were relatively unchanged over the survey period, but the amounts of acidifying sulphur compounds decreased by approximately 50%. We constructed a linear regression model to assess the relation between the rate of change in pH (normalised to an annual basis) and the rate of change in acid deposition, as modified by soil properties (pH, clay content, organic matter content), rainfall and past acid deposition. We used data on rainfall and acid deposition over the survey period on the same 5-km grid as the NSI data. We fitted the model separately for each land use category. The results for arable land showed a significant effect of the change in rate of acid deposition, though a significant part of the

  12. Investigation of VOC Transport in Soil Vapors due to Wind Effects using Models and Measurement

    NASA Astrophysics Data System (ADS)

    Pennell, K. G.; Roghani, M.; Shirazi, E.; Willett, E.

    2014-12-01

    For the past several years, vapor intrusion of volatile organic compounds (VOCs) that emanate from hazardous waste sites has been gaining attention due to adverse health effects and regulatory action. Most studies of VOC vapor intrusion suggest that diffusion is the dominant contaminant transport mechanism, while advection is only considered important near contaminant entry points (i.e. building cracks). This conceptual framework is accurate when above-ground surface features do not promote air flow into (or out of) the ground surface. Recent research related to air flow in the atmospheric boundary layer (ABL) due to wind effects around buildings suggests a need for better understanding how advective transport processes can impact contaminant profiles and vapor intrusion exposure risks. In this study, a numerical model using COMSOL Multiphysics was developed to account for parameters affecting the transport of VOCs from the subsurface into buildings by considering wind effects in the ABL. Model simulations are compared to preliminary laboratory and field data to evaluate the relative importance of wind induced pressure gradients, soil permeability, soil porosity, and soil effective diffusivity on vapor intrusion entry rates. The major goal of this research is to develop an improved conceptual understanding of the vapor intrusion process so that remediation efforts can be better designed and implemented.

  13. Plant adaptation to acid soils: the molecular basis for crop aluminum resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum (Al) toxicity on acid soils is a significant limitation to crop production worldwide, as approximately 50% of the world’s potentially arable soils are acidic. Because acid soils are such an important constraint to agriculture, understanding the mechanisms and genes conferring resistance to ...

  14. Reduction of Cr(VI) by malic acid in aqueous Fe-rich soil suspensions.

    PubMed

    Zhong, Laiyuan; Yang, Jiewen

    2012-03-01

    Detoxification of Cr(VI) through reduction by organic reductants has been regarded as an effective way for remediation of Cr(VI)-polluted soils. However, such remediation strategy would be limited in practical applications due to the low Cr(VI) reduction rate. In this study, the catalytic effect of two Fe-rich soils (Ultisol and Oxisol) on Cr(VI) reduction by malic acid was evaluated. As the results shown, the two soils could obviously accelerate the reduction of Cr(VI) by malic acid at low pH conditions, while such catalytic effect was gradually suppressed as the increase in pH. After reaction for 48 h at pH 3.2, Oxalic acid was found in the supernatant of Ultisol, suggesting the oxidization of hydroxyl in malic acid to carboxyl and breakage of the bond between C(2) and C(3). It was also found that the catalytic reactivity of Ultisol was more significant than that of Oxisol, which could be partly attributed to the fact that the amount of Fe(II) released from the reductive dissolution of Ultisol by malic acid was larger than that of Oxisol. With addition of Al(III), the catalytic effect from Ultisol was inhibited across the pH range examined. On the contrary, the presence of Cu(II) would increase the catalytic effect of Ultisol, which was more pronounced with the increase in pH. This study proposed a potential way for elimination of the environmental risks posed by the Cr(VI) contamination by use of the natural soil surfaces to catalyze Cr(VI) reduction by the organic reductant such as malic acid, a kind of organic reductant originating from soil organic decomposition process or plant excretion.

  15. [Amelioration effects of wastewater sludge biochars on red soil acidity and their environmental risk].

    PubMed

    Lu, Zai-Liang; Li, Jiu-Yu; Jiang, Jun; Xu, Ren-Kou

    2012-10-01

    Biochars were prepared from wastewater sludge from two wastewater treatment plants in Nanjing using a pyrolysis method at 300, 500 and 700 degrees C. The properties of the biochars were measured, and their amelioration effects on the acidity of a red soil and environmental risk of application of sludge biochars were examined to evaluate the possibility of agricultural application of wastewater sludge biochars in red soils. Results indicated that incorporation of both sludge and sludge biochar increased soil pH due to the alkalinity of sludge and sludge biochar, and the mineralization of organic N and nitrification of ammonium N from wastewater sludge induced soil pH fluctuated during incubation. The amelioration effects of biochars generated at 500 and 700 degrees C on the soil were significantly greater than that of sludge significantly. Sludge and sludge biochar contain ample base cations of Ca2+, Mg2+, K+ and Na+ and thus incorporation of sludge and sludge biochar increased the contents of soil exchangeable base cations and decreased soil exchangeable aluminum and H+. Contents of heavy metals in sludge biochars were greater than these in their feedstock sludge, while the contents of Cu, Pb, Ni and As in sludge biochars were lower than the standard values of heavy metals were wastewater sludge for agricultural use in acid soils in China except for Zn and Cd. The contents of available forms of heavy metals in the biochars generated from sludge from Chengdong wastewater treatment plant was lower than these in the corresponding sludge, suggesting that pyrolysis proceed decreased the activity of heavy metals in wastewater sludge. After 90-day incubation of the soil with sludge and sludge biochar, the differences in the contents of soil available heavy metals were not significant between the biochars and their feedstock sludge from Jiangxizhou wastewater treatment plant, and the contents in the treatments with biochars added was lower than these in the treatments with

  16. Adsorption of glyphosate and aminomethylphosphonic acid in soils

    NASA Astrophysics Data System (ADS)

    Rampazzo, N.; Rampazzo Todorovic, G.; Mentler, A.; Blum, W. E. H.

    2013-03-01

    The results showed that glyphosate is initially adsorbed mostly in the upper 2 cm. It is than transported and adsorbed after few days in deeper soil horizons with concomitant increasing content of its metabolite aminomethylphosphonic acid. Moreover, Fe-oxides seem to be a key parameter for glyphosate and aminomethylphosphonic adsorption in soils. This study confirmed previous studies: the analysis showed lower contents of dithionite-soluble and Fe-oxides for the Chernozem, with consequently lower adsorption of glyphosate and aminomethylphosphonic as compared with the Cambisol and the Stagnosol.

  17. High abundance of Crenarchaeota in a temperate acidic forest soil.

    PubMed

    Kemnitz, Dana; Kolb, Steffen; Conrad, Ralf

    2007-06-01

    The objective of the study was to elucidate the depth distribution and community composition of Archaea in a temperate acidic forest soil. Numbers of Archaea and Bacteria were measured in the upper 18 cm of the soil, and soil cores were sampled on two separate occasions using quantitative PCR targeting 16S rRNA genes. Maximum numbers of Archaea were 0.6-3.8 x 10(8) 16S rRNA genes per gram of dry soil. Numbers of Bacteria were generally higher, but Archaea always accounted for a high percentage of the total gene numbers (12-38%). The archaeal community structure was analysed by the construction of clone libraries and by terminal restriction length polymorphism (T-RFLP) using the same Archaea-specific primers. With the reverse primer labelled, T-RFLP analysis led to the detection of four T-RFs. Three had lengths of 83, 185 and 218 bp and corresponded to uncultured Crenarchaeota. One (447 bp) was assigned to Thermoplasmales. Labelling of the forward primer allowed further separation of the T-RF into Crenarchaeota Group I.1c and Group I.1b, and indicated that Crenarchaeota of the Group I.1c were the predominant 16S rRNA genotype (soil. The abundance of Archaea and concentration of ammonia and nitrate decreased with soil depth. Hence it is unclear if the detected Crenarchaeota Group I.1c participated in ammonia oxidation or had another phenotype.

  18. Gamma exposure rates due to neutron activation of soil: site of Hood detonation, Operation Plumbbob

    SciTech Connect

    Auxier, J.A.; Ohnesorge, W.F.

    1980-06-01

    This paper is the result of some recent discussions of exposure rates within the first few hours of the Hood detonation of the Plumbbob series due to neutron activation of soil. We estimated the exposure rates from 1/2 to 3 h after the detonation from ground zero to 1000 yards from ground zero. The area was assumed to be uncontaminated by fallout. Soil samples from the area of the Nevada Test Site at which the Hood device was detonated were sent to ORNL by Dr. John Malik of Los Alamos and by Mr. Gordon Jacks of the Nevada Test Site. These samples were irradiated at the DOSAR facility and the resulting activity analyzed. Calculations of exposure rates were then made based on the analyzed activity and the measured thermal neutron fluences at DOSAR and at the Hood Site.

  19. A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

    PubMed

    Pannatier, Elisabeth Graf; Thimonier, Anne; Schmitt, Maria; Walthert, Lorenz; Waldner, Peter

    2011-03-01

    Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

  20. Fast changes in seasonal forest communities due to soil moisture increase after damming.

    PubMed

    do Vale, Vagner Santiago; Schiavini, Ivan; Araújo, Glein Monteiro; Gusson, André Eduardo; Lopes, Sérgio de Faria; de Oliveira, Ana Paula; do Prado-Júnior, Jamir Afonso; Arantes, Carolina de Silvério; Dias-Neto, Olavo Custodio

    2013-12-01

    Local changes caused by dams can have drastic consequences for ecosystems, not only because they change the water regime but also the modification on lakeshore areas. Thus, this work aimed to determine the changes in soil moisture after damming, to understand the consequences of this modification on the arboreal community of dry forests, some of the most endangered systems on the planet. We studied these changes in soil moisture and the arboreal community in three dry forests in the Araguari River Basin, after two dams construction in 2005 and 2006, and the potential effects on these forests. For this, plots of 20 m x 10 m were distributed close to the impoundment margin and perpendicular to the dam margin in two deciduous dry forests and one semi-deciduous dry forest located in Southeastern Brazil, totaling 3.6 ha sampled. Besides, soil analysis were undertaken before and after impoundment at three different depths (0-10, 20-30 and 40-50 cm). A tree (minimum DBH of 4.77 cm) community inventory was made before (TO) and at two (T2) and four (T4) years after damming. Annual dynamic rates of all communities were calculated, and statistical tests were used to determine changes in soil moisture and tree communities. The analyses confirmed soil moisture increases in all forests, especially during the dry season and at sites closer to the reservoir; besides, an increase in basal area due to the fast growth of many trees was observed. The highest turnover occurred in the first two years after impoundment, mainly due to the higher tree mortality especially of those closer to the dam margin. All forests showed reductions in dynamic rates for subsequent years (T2-T4), indicating that these forests tended to stabilize after a strong initial impact. The modifications were more extensive in the deciduous forests, probably because the dry period resulted more rigorous in these forests when compared to semideciduous forest. The new shorelines created by damming increased soil

  1. Acid sulfate soils are an environmental hazard in Finland

    NASA Astrophysics Data System (ADS)

    Pihlaja, Jouni

    2016-04-01

    Acid sulfate soils (ASS) create significant threats to the environment on coastal regions of the Baltic Sea in Finland. The sediments were deposited during the ancient Litorina Sea phase of the Baltic Sea about 7500-4500 years ago. Finland has larger spatial extent of the ASS than any other European country. Mostly based on anthropogenic reasons (cultivation, trenching etc.) ASS deposits are currently being exposed to oxygen which leads to chemical reaction creating sulfuric acid. The acidic waters then dissolve metals form the soil. Acidic surface run off including the metals are then leached into the water bodies weakening the water quality and killing fish or vegetation. In constructed areas acidic waters may corrode building materials. Geological Survey of Finland (GTK) is mapping ASS deposits in Finland. The goal is to map a total of 5 million hectares of the potentially ASS affected region. It has been estimated that the problematic Litorina Sea deposits, which are situated 0-100 m above the recent Baltic Sea shoreline, cover 500 000 hectares area. There are several phases in mapping. The work begins at the office with gathering the existing data, interpreting airborne geophysical data and compiling a field working plan. In the field, quality of the soil is studied and in uncertain cases samples are taken to laboratory analyses. Also electrical conductivity and pH of soil and water are measured in the field. Laboratory methods include multielemental determinations with ICP-OES, analyses of grain size and humus content (LOI), and incubation. So far, approximately 60 % of the potential ASS affected regions in Finland are mapped. Over 15 000 sites have been studied in the field and 4000 laboratory analyses are done. The spatial database presented in the scale of 1: 250 000 can be viewed at the GTK's web pages (http://gtkdata.gtk.fi/hasu/index.html).

  2. Simple method of isolating humic acids from organic soils

    NASA Astrophysics Data System (ADS)

    Ahmed, O.

    2009-04-01

    Humic substances particularly humic acids (HA) play a major role in soil conditioning e.g. erosion control, soil cation exchange capacity, complexation of heavy metal ions and pesticides, carbon and nitrogen cycles, plant growth and reduction of ammonia volatilization from urea. Humified substances such as coal, composts, and peat soils have substantial amounts of HA but the isolation of these acids is expensive, laborious, and time consuming. Factors that affect the quality and yield of HA isolated from these materials include extraction, fractionation, and purification periods. This work developed a simple, rapid, and cost effective method of isolating HA from peat soils. There was a quadratic relationship between extraction period and HA yield. Optimum extraction period was estimated at 4 h instead of the usual range of 12 to 48 h. There was no relationship between fractionation period and HA yield. As such 2 h instead of the usual range of 12 to 24 h fractionation period could be considered optimum. Low ash content (5%), remarkable reduction in K, coupled with the fact that organic C, E4/E6, carboxylic COOH, phenolic OH, and total acidity values of the HA were consistent with those reported by other authors suggest that the HA dealt with were free from mineral matter. This was possible because the distilled water used to purify the HA served as Bronsted-Lowry acid during the purification process of the HA. Optimum purification period using distilled waster was 1 h instead of the usual range of 1 and 7 days (uses HF and HCl and dialysis). Humic acids could be isolated from tropical peat soils within 7 h (i.e. 4 h extraction, 2 h fractionation, and 1 h purification) instead of the existing period of 2 and 7 days. This could facilitate the idea of producing organic fertilizers such as ammonium-humate and potassium-humate from humified substances since techniques devised in this study did not alter the true nature of the HA. Besides, the technique is rapid, simple

  3. Negative plant-soil feedbacks may limit persistence of an invasive tree due to rapid accumulation of soil pathogens.

    PubMed

    Nijjer, Somereet; Rogers, William E; Siemann, Evan

    2007-10-22

    Soil organisms influence plant species coexistence and invasion potential. Plant-soil feedbacks occur when plants change soil community composition such that interactions with that soil community in turn may positively or negatively affect the performance of conspecifics. Theories predict and studies show that invasions may be promoted by stronger negative soil feedbacks for native compared with exotic species. We present a counter-example of a successful invader with strong negative soil feedbacks apparently caused by host-specific, pathogenic soil fungi. Using a feedback experiment in pots, we investigated whether the relative strength of plant-soil feedbacks experienced by a non-native woody invader, Sapium sebiferum, differed from several native tree species by examining their performance in soils collected near conspecifics ('home soils') or heterospecifics ('away soils') in the introduced range. Sapium seedlings, but no native seedlings, had lower survival and biomass in its home soils compared with soils of other species (negative feedback'). To investigate biotic agents potentially responsible for the observed negative feedbacks, we conducted two additional experiments designed to eliminate different soil taxa ('rescue experiments'). We found that soil sterilization (pot experiment ) or soil fungicide applications (pot and field experiments) restored Sapium performance in home soil thereby eliminating the negative feedbacks we observed in the original experiment. Such negative feedbacks apparently mediated by soil fungi could have important effects on persistence of this invader by limiting Sapium seedling success in Sapium dominated forests (home soils) though their weak effects in heterospecific (away) soils suggest a weak role in limiting initial establishment.

  4. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid

    PubMed Central

    Donaldson, Melissa A.; Bish, David L.; Raff, Jonathan D.

    2014-01-01

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day. PMID:25512517

  5. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid.

    PubMed

    Donaldson, Melissa A; Bish, David L; Raff, Jonathan D

    2014-12-30

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼ 3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day.

  6. Optimizing available phosphorus in calcareous soils fertilized with diammonium phosphate and phosphoric acid using Freundlich adsorption isotherm.

    PubMed

    Naeem, Asif; Akhtar, Muhammad; Ahmad, Waqar

    2013-01-01

    In calcareous soils, phosphorus (P) retention and immobilization take place due to precipitation and adsorption. Since soil pH is considered a major soil variable affecting the P sorption, an acidic P fertilizer could result in low P adsorption compared to alkaline one. Therefore, P adsorption from DAP and phosphoric acid (PA) required to produce desired soil solution P concentration was estimated using Freundlich sorption isotherms. Two soils from Faisalabad and T. T. Singh districts were spiked with 0, 10, and 20 % CaCO3 for 15 days. Freundlich adsorption isotherms (P = aC(b/a)) were constructed, and theoretical doses of PA and DAP to develop a desired soil solution P level (i.e., 0.20 mg L(-1)) were calculated. It was observed that P adsorption in soil increased with CaCO3. Moreover, at all the levels of CaCO3, P adsorption from PA was lower compared to that from DAP in both the soils. Consequently, lesser quantity of PA was required to produce desired solution P, 0.2 mg L(-1), compared to DAP. However, extrapolating the developed relationship between soil CaCO3 contents and quantity of fertilizer to other similar textured soils needs confirmation.

  7. Soil peroxidase-mediated chlorination of fulvic acid

    NASA Astrophysics Data System (ADS)

    Asplund, Gunilla; Borén, Hans; Carlsson, Uno; Grimvall, Anders

    Humic matter has recently been shown to contain considerable quantities of naturally produced organohalogens. The present study investigated the possibility of a non-specific, enzymatically mediated halogenation of organic matter in soil. The results showed that, in the presence of chloride and hydrogen peroxide, the enzyme chloroperoxidase (CPO) from the fungus Caldariomyces fumago catalyzes chlorination of fulvic acid. At pH 2.5 - 6.0, the chlorine to fulvic acid ratio in the tested sample was elevated from 12 mg/g to approximately 40-50 mg/g. It was also shown that this reaction can take place at chloride and hydrogen peroxide concentrations found in the environment. An extract from spruce forest soil was shown to have a measurable chlorinating capacity. The activity of an extract of 0.5 kg soil corresponded to approximately 0.3 enzyme units, measured as CPO activity. Enzymatically mediated halogenation of humic substances may be one of the mechanisms explaining the widespread occurrence of adsorbable organic halogens (AOX) in soil and water.

  8. Extraction and Analysis of Microbial Phospholipid Fatty Acids in Soils

    PubMed Central

    Quideau, Sylvie A.; McIntosh, Anne C.S.; Norris, Charlotte E.; Lloret, Emily; Swallow, Mathew J.B.; Hannam, Kirsten

    2016-01-01

    Phospholipid fatty acids (PLFAs) are key components of microbial cell membranes. The analysis of PLFAs extracted from soils can provide information about the overall structure of terrestrial microbial communities. PLFA profiling has been extensively used in a range of ecosystems as a biological index of overall soil quality, and as a quantitative indicator of soil response to land management and other environmental stressors. The standard method presented here outlines four key steps: 1. lipid extraction from soil samples with a single-phase chloroform mixture, 2. fractionation using solid phase extraction columns to isolate phospholipids from other extracted lipids, 3. methanolysis of phospholipids to produce fatty acid methyl esters (FAMEs), and 4. FAME analysis by capillary gas chromatography using a flame ionization detector (GC-FID). Two standards are used, including 1,2-dinonadecanoyl-sn-glycero-3-phosphocholine (PC(19:0/19:0)) to assess the overall recovery of the extraction method, and methyl decanoate (MeC10:0) as an internal standard (ISTD) for the GC analysis. PMID:27685177

  9. Influence of metal ions and pH on the hydraulic properties of potential acid sulfate soils

    NASA Astrophysics Data System (ADS)

    Le, T. M. H.; Collins, R. N.; Waite, T. D.

    2008-07-01

    SummaryAcid sulfate soils (ASS) cover extensive areas of east Australian coastal floodplains. Upon oxidation, these hydromorphic pyritic sediments produce large quantities of sulfuric acid. In addition, due to their geographic location, these soils may also come in contact with high ionic strength estuarine tidal waters. As a result, there is typically a large variation in acidity (pH) and cation concentrations in soil porewaters and adjacent aquatic systems (e.g., agricultural field drains, rivers, estuaries, etc.). Acid sulfate soils, especially from the unoxidized gelatinous deeper layers, contain a relatively high proportion of montmorillonite, which is wellknown for its shrink-swell properties. Variations in cation concentrations, including H3O+, can influence montmorillonite platelet interactions and may, thus, also significantly affect the hydraulic conductivity of materials containing this clay. In this paper we report on the effect of four common cations, at reasonable environmental concentrations, on the hydraulic properties of potential (unoxidized) acid sulfate soil materials. The natural system was simplified by examining individually the effects of each cation (H+, Ca2+, Fe2+ and Na+) on a soil-water suspension in a filtration cell unit. Moisture ratio, hydraulic conductivity and the consolidation coefficient of the deposited filter cakes were calculated using material coordinates theory. The results indicate that the hydraulic conductivity of potential acid sulfate soils increases at low pH and with cation concentration. Although an increase in the charge of amphoteric edge groups on montmorillonite clays may result in some aggregation between individual clay platelets, we conclude that the extent of these changes are unlikely to cause significant increases in the transportation of acidity (and contaminants) through potential acid sulfate soils as the hydraulic conductivity of these materials remain low (<10-9 m/s) at pH and ionic conditions normally

  10. Ecotoxicity of boric acid in standard laboratory tests with plants and soil organisms.

    PubMed

    Princz, Juliska; Becker, Leonie; Scheffczyk, Adam; Stephenson, Gladys; Scroggins, Rick; Moser, Thomas; Römbke, Jörg

    2017-03-17

    To verify the continuous sensitivity of ecotoxicological tests (mainly the test organisms), reference substances with known toxicity are regularly tested. Ideally, this substance(s) would lack specificity in its mode action, be bioavailable and readily attainable with cost-effective means of chemical characterization. Boric acid has satisfied these criteria, but has most recently been characterized as a substance of very high concern, due to reproductive effects in humans, thus limiting its recommendation as an ideal reference toxicant. However, there is probably no other chemical for which ecotoxicity in soil has been so intensively studied; an extensive literature review yielded lethal (including avoidance) and sublethal data for 38 taxa. The ecotoxicity data were evaluated using species sensitivity distributions, collectively across all taxa, and separately according to species type, endpoints, soil type and duration. The lack of specificity in the mode of action yielded broad toxicity among soil taxa and soil types, and provided a collective approach to assessing species sensitivity, while taking into consideration differences in test methodologies and exposure durations. Toxicity was species-specific with Folsomia candida and enchytraied species demonstrating the most sensitivity; among plants, the following trend occurred: dicotyledonous (more sensitive) ≫ monocotyledonous ≫ gymnosperm species. Sensitivity was also time and endpoint specific, with endpoints such as lethality and avoidance being less sensitive than reproduction effects. Furthermore, given the breadth of data and toxicity demonstrated by boric acid, lessons learned from its evaluation are discussed to recommend the properties required by an ideal reference substance for the soil compartment.

  11. Soil degradation in semi-arid grasslands due to intensive grazing in Northern China

    NASA Astrophysics Data System (ADS)

    Wiesmeier, M.; Steffens, M.; Kölbl, A.; Kögel-Knabner, I.

    2012-04-01

    organic matter input, destruction of soil aggregates due to enhanced animal trampling associated with mineralization of formerly protected SOM and enhanced soil erosion. The analysis of the spatial distribution of SOM showed a small-scale homogenization of SOM at grazed sites compared with a heterogeneous pattern at ungrazed sites. Apparently, heterogeneously distributed grass tussocks, which act as "islands of fertility" in undisturbed steppe ecosystems, are removed by heavy grazing that in turn deteriorates the accumulation of SOM. We conclude that semi-arid grasslands of Northern China are very susceptible to intensive grazing, which led to a considerable depletion and a spatial homogenization of SOM. Further intensification of the grazing management or an extension into undisturbed boundary areas of the steppe should be prevented.

  12. Cesium-137 deposition and contamination of Japanese soils due to the Fukushima nuclear accident

    PubMed Central

    Yasunari, Teppei J.; Stohl, Andreas; Hayano, Ryugo S.; Burkhart, John F.; Eckhardt, Sabine; Yasunari, Tetsuzo

    2011-01-01

    The largest concern on the cesium-137 (137Cs) deposition and its soil contamination due to the emission from the Fukushima Daiichi Nuclear Power Plant (NPP) showed up after a massive quake on March 11, 2011. Cesium-137 (137Cs) with a half-life of 30.1 y causes the largest concerns because of its deleterious effect on agriculture and stock farming, and, thus, human life for decades. Removal of 137Cs contaminated soils or land use limitations in areas where removal is not possible is, therefore, an urgent issue. A challenge lies in the fact that estimates of 137Cs emissions from the Fukushima NPP are extremely uncertain, therefore, the distribution of 137Cs in the environment is poorly constrained. Here, we estimate total 137Cs deposition by integrating daily observations of 137Cs deposition in each prefecture in Japan with relative deposition distribution patterns from a Lagrangian particle dispersion model, FLEXPART. We show that 137Cs strongly contaminated the soils in large areas of eastern and northeastern Japan, whereas western Japan was sheltered by mountain ranges. The soils around Fukushima NPP and neighboring prefectures have been extensively contaminated with depositions of more than 100,000 and 10,000 MBq km-2, respectively. Total 137Cs depositions over two domains: (i) the Japan Islands and the surrounding ocean (130–150 °E and 30–46 °N) and, (ii) the Japan Islands, were estimated to be more than 5.6 and 1.0 PBq, respectively. We hope our 137Cs deposition maps will help to coordinate decontamination efforts and plan regulatory measures in Japan. PMID:22084074

  13. The application of exogenous cellulase to improve soil fertility and plant growth due to acceleration of straw decomposition.

    PubMed

    Han, Wei; He, Ming

    2010-05-01

    The effects of exogenous cellulase application on straw decomposition, soil fertility, and plant growth were investigated with nylon bag and pot experiments. Cellulase application promoted straw decomposition, and the decomposition rates of rice and wheat straw increased by 6.3-26.0% and 6.8-28.0%, respectively, in the nylon bag experiments. In pot experiments soil-available N and P contents, soil cellulase activity, and growth of rice seedlings increased. Soil respiration rate and microbial population were unaffected. Seventy Ug(-1) was the optimal cellulase concentration for plant growth. The exogenous cellulase persisted in soil for more than 100days. Although the data show that exogenous cellulase application can enhance soil fertility and plant growth in the short-term due to the acceleration of straw decomposition and has the potential to be an environment-friendly approach to manage straw, cellulase application to soil seems currently not economical.

  14. Solubilization of manganese and trace metals in soils affected by acid mine runoff.

    PubMed

    Green, C H; Heil, D M; Cardon, G E; Butters, G L; Kelly, E F

    2003-01-01

    Manganese solubility has become a primary concern in the soils and water supplies in the Alamosa River basin, Colorado due to both crop toxicity problems and concentrations that exceed water quality standards. Some of the land in this region has received inputs of acid and trace metals as a result of irrigation with water affected by acid mine drainage and naturally occurring acid mineral seeps. The release of Mn, Zn, Ni, and Cu following saturation with water was studied in four soils from the Alamosa River basin. Redox potentials decreased to values adequate for dissolution of Mn oxides within 24 h following saturation. Soluble Mn concentrations were increased to levels exceeding water quality standards within 84 h. Soluble concentrations of Zn and Ni correlated positively with Mn following reduction for all four soils studied. The correlation between Cu and Mn was significant for only one of the soils studied. The soluble concentrations of Zn and Ni were greater than predicted based on the content of each of these metals in the Mn oxide fraction only. Increases in total electrolyte concentration during reduction indicate that this may be the result of displacement of exchangeable metals by Mn following reductive dissolution of Mn oxides.

  15. [The optimization of the soil acidity of agrocenosis contaminated 137Cs and 90Sr: threshold parameters].

    PubMed

    Putiatin, Iu V; Seraia, T M

    2005-01-01

    During the field researches were determined the differences between agrochemical optimum of the acidity of the Sod-podzol loamy sand soil, which provides high productivity of the crops and the pH-value, which provides the minimal accumulation of 137Cs and of 90Sr by the biomass (the ecological optimum). On the average for the majority of the agricultural plants the minimal accumulations of 137Cs and of 90Sr are noticed under pHKCl 6.7, which is higher than agrochemical optimum on 0.7. The efficiency of liming under the discrimination of 137Cs and of 90Sr is much higher in soils with low values of pH. On the average, in crop rotation due to decreasing of the acidity in the soil from 4.9 to 5.9 pHKCl, the crop yield has grown on 9%, 137Cs contents has decreased on 16.7%, 90Sr--on 23.7%. The further decreasing of the soil acidity (from 5.9 to 6.8 pHKCl) was poorly effective: the productivity didn't change essentially. The transfer of 137Cs decreased on 8.9% and of 90Sr on 8.4%.

  16. Acid washing and stabilization of an artificial arsenic-contaminated soil.

    PubMed

    Tokunaga, Shuzo; Hakuta, Toshikatsu

    2002-01-01

    An acid-washing process was studied on a laboratory scale to extract the bulk of arsenic(V) from a highly contaminated Kuroboku soil (Andosol) so as to minimize the risk of arsenic to human health and the environment. The sorption and desorption behavior of arsenic in the soil suggested the possibility of arsenic leaching under acidic conditions. Artificially contaminated Kuroboku soil (2830 mg As/kg soil) was washed with different concentrations of hydrogen fluoride, phosphoric acid, sulfuric acid, hydrogen chloride, nitric acid, perchloric acid, hydrogen bromide, acetic acid, hydrogen peroxide, 3:1 hydrogen chloride-nitric acid, or 2:1 nitric acid-perchloric acid. Phosphoric acid proved to be most promising as an extractant, attaining 99.9% arsenic extraction at 9.4% acid concentration in 6 h. Sulfuric acid also attained high percentage extraction. The arsenic extraction by these acids reached equilibrium within 2 h. Elovich-type equation best described most of the kinetic data for dissolution of soil components as well as for extraction of arsenic. Dissolution of the soil components could be minimized by ceasing acid washing in 2 h. The acid-washed soil was further stabilized by the addition of lanthanum, cerium, and iron(III) salts or their oxides or hydroxides which form insoluble complex with arsenic. Both salts and oxides of lanthanum and cerium were effective in immobilizing arsenic in the soil attaining less than 0.01 mg/l As in the leaching test.

  17. Negative plant–soil feedbacks may limit persistence of an invasive tree due to rapid accumulation of soil pathogens

    PubMed Central

    Nijjer, Somereet; Rogers, William E; Siemann, Evan

    2007-01-01

    Soil organisms influence plant species coexistence and invasion potential. Plant–soil feedbacks occur when plants change soil community composition such that interactions with that soil community in turn may positively or negatively affect the performance of conspecifics. Theories predict and studies show that invasions may be promoted by stronger negative soil feedbacks for native compared with exotic species. We present a counter-example of a successful invader with strong negative soil feedbacks apparently caused by host-specific, pathogenic soil fungi. Using a feedback experiment in pots, we investigated whether the relative strength of plant–soil feedbacks experienced by a non-native woody invader, Sapium sebiferum, differed from several native tree species by examining their performance in soils collected near conspecifics (‘home soils’) or heterospecifics (‘away soils’) in the introduced range. Sapium seedlings, but no native seedlings, had lower survival and biomass in its home soils compared with soils of other species (‘negative feedback’). To investigate biotic agents potentially responsible for the observed negative feedbacks, we conducted two additional experiments designed to eliminate different soil taxa (‘rescue experiments’). We found that soil sterilization (pot experiment) or soil fungicide applications (pot and field experiments) restored Sapium performance in home soil thereby eliminating the negative feedbacks we observed in the original experiment. Such negative feedbacks apparently mediated by soil fungi could have important effects on persistence of this invader by limiting Sapium seedling success in Sapium dominated forests (home soils) though their weak effects in heterospecific (away) soils suggest a weak role in limiting initial establishment. PMID:17711837

  18. Processes and fluxes during the initial stage of acid sulfate soil formation

    NASA Astrophysics Data System (ADS)

    Gröger, J.; Hamer, K.; Schulz, H. D.

    2009-04-01

    Acid sulfate soils occur over a wide range of climatic zones, mainly in coastal landscapes. In these soils, the release of sulfuric acid by the oxidation of pyrite generates a very acidic environment (e.g., DENT and PONS, 1995, PONS, 1973). Two major types of acid sulfate soils can be distinguished: In actual acid sulfate soils, the initially contained pyrite was at least partly oxidized. This resulted in a severe acidification of the soil. Potential acid sulfate soils are generally unoxidized and contain large amounts of pyrite. Upon oxidation, these soils will turn into actual acid sulfate soils. By excavation or lowering of the groundwater table, potential acid sulfate soils can be exposed to atmospheric oxygen. During oxidation the pH drops sharply to values below pH 4. This acidification promotes the release of various metals, e.g., alumina, iron and heavy metals. Additionally, large quantities of sulfate are released. In order to assess the effects of disturbances of potential acid sulfate soils, for example by excavations during construction works, several large scale column experiments were conducted with various types of potential acid sulfate soils from Northern Germany. In these experiments, the oxidation and initial profile development of pyritic fen peats and thionic fluvisols were studied over a period of 14 months. The study focused on leaching and the translocation of various metals in the soil profile. To study mobilization processes, element fluxes and the progress of acidification, soil water and leachate were analyzed for total element concentrations. Furthermore, several redox-sensitive parameters, e.g., Fe2+ and sulfide, were measured and changes to the initial solid phase composition were analyzed. Chemical equilibria calculations of the soil water were used to gain insights into precipitation processes of secondary products of pyrite oxidation and leaching products. The results of this study will support the assessment of risks deriving from

  19. Sorption of acidic organic solute onto kaolinitic soils from methanol-water mixtures.

    PubMed

    Kim, Juhee; Kim, Minhee; Hyun, Seunghun; Kim, Jeong-Gyu; Ok, Yong Sik

    2012-01-01

    The fate of the acidic organic solute from the soil-water-solvent system is not well-understood. In this study, the effect of the acidic functional group of organic solute in the sorption from cosolvent system was evaluated. The sorption of naphthalene (NAP) and 1-naphthoic acid (1-NAPA) by three kaolinitic soils and two model sorbents (kaolinite and humic acid) were measured as functions of the methanol volume fractions (f (c) ≤ 0.4) and ionic compositions (CaCl(2) and KCl). The solubility of 1-NAPA was also measured in various ionic compositions. The sorption data were interpreted using the cosolvency-induced sorption model. The K (m) values (= the linear sorption coefficient) of NAP with kaolinitic soil for both ionic compositions was log linearly decreased with f (c). However, the K (m) values of 1-NAPA with both ionic compositions remained relatively constant over the f (c) range. For the model sorbent, the K (m) values of 1-NAPA with kaolinite for the KCl system and with humic acid for both ionic compositions decreased with f (c), while the sorption of 1-NAPA with kaolinite for the CaCl(2) system was increased with f (c). From the solubility data of 1-NAPA with f (c), no significant difference was observed with the different ionic compositions, indicating an insignificant change in the aqueous activity of the liquid phase. In conclusion, the enhanced 1-NAPA sorption, greater than that predicted from the cosolvency-induced model, was due to an untraceable interaction between the carboxylate and hydrophilic soil domain in the methanol-water system. Therefore, in order to accurately predict the environmental fate of acidic pesticides and organic solutes, an effort to quantitatively incorporate the enhanced hydrophilic sorption into the current cosolvency-induced sorption model is required.

  20. Fatality due to acute fluoride poisoning following dermal contact with hydrofluoric acid in a palynology laboratory.

    PubMed

    Muriale, L; Lee, E; Genovese, J; Trend, S

    1996-12-01

    A fatal accident involving concentrated hydrofluoric acid in a palynological laboratory is described. Similar deaths due to dermal exposure to concentrated hydrofluoric acid have been reported in the literature. It is evident that rigorous control measures including proper personal protective equipment and first aid are of utmost importance in the prevention of death and injury when handling hydrofluoric acid. Possible factors that may have contributed to the accident are reviewed.

  1. Do soil Fe transformation and secretion of low-molecular-weight organic acids affect the availability of Cd to rice?

    PubMed

    Chen, Xue; Yang, Yazhou; Liu, Danqing; Zhang, Chunhua; Ge, Ying

    2015-12-01

    The bioavailability of cadmium (Cd) to rice may be complicated by chemical and biological factors in the rhizosphere. The aim of this work is to investigate how soil iron (Fe) redox transformations and low-molecular-weight organic acid (LMWOA) exudation from root affect Cd accumulation in rice. Two soils (a paddy soil and a saline soil) with different physicochemical properties were used in this study. Soil redox conditions were changed by flooding and addition of organic matter (OM). Two days after the soil treatments, rice seedlings were transplanted in a vermiculite-soil system and grown for 10 days. We measured pH and Eh, LMWOA, Fe and Cd contents in rice, and their fractions in the soils and vermiculite. Cadmium accumulation in rice declined in both soils upon the flooding and OM treatment. Iron dissolution in the paddy soil and its deposition in the rhizosphere significantly increased upon the OM addition, but the concentration of Fe plaque on the rice root significantly declined. Conversely, although Fe transformed into less active fractions in the saline soil, Fe accumulation on the surface and in the tissue of root was considerably enhanced. The secretion of LMWOA was remarkably induced when the OM was amended in the saline soil, but the same effect was not observed in the paddy soil. Reduction of Cd uptake by rice could be attributed to different factors in the two soils. For the paddy soil, the lowered Cd bioavailability was likely due to the competition of Fe and Cd for the binding sites on the vermiculite surface. For the saline soil, however, rice responded to the low Fe mobility through more LMWOA exudation and Fe plaque formation, and their increases could explain the decrease of rice Cd.

  2. Interactive effects of soil acidity and fluoride on soil solution aluminium chemistry and barley (Hordeum vulgare L.) root growth.

    PubMed

    Manoharan, V; Loganathan, P; Tillman, R W; Parfitt, R L

    2007-02-01

    A greenhouse study was conducted to determine if concentrations of fluoride (F), which would be added to acid soils via P fertilisers, were detrimental to barley root growth. Increasing rates of F additions to soil significantly increased the soil solution concentrations of aluminium (Al) and F irrespective of the initial adjusted soil pH, which ranged from 4.25 to 5.48. High rates of F addition severely restricted root growth; the effect was more pronounced in the strongly acidic soil. Speciation calculations demonstrated that increasing rates of F additions substantially increased the concentrations of Al-F complexes in the soil. Stepwise regression analysis showed that it was the combination of the activities of AlF2(1+) and AlF(2+) complexes that primarily controlled barley root growth. The results suggested that continuous input of F to soils, and increased soil acidification, may become an F risk issue in the future.

  3. Quantification of Plume-Soil Interaction and Excavation Due to the Sky Crane Descent Stage

    NASA Technical Reports Server (NTRS)

    Vizcaino, Jeffrey; Mehta, Manish

    2015-01-01

    data obtained from MSL's navigation camera (NAVCAM) pairs on Sols 002, 003, and 016 were used to virtually recreate local surface topography and features around the rover by means of stereoscopic depth mapping. Images taken simultaneously by the left and right navigation cameras located on the rover's mast assembly spaced 42 centimeters were used to generate a three dimensional depth map from flat, two dimensional images of the same feature at slightly different angles. Image calibration with physical hardware on the rover and known terrain features were used to provide scaling information that accurately sizes features and regions of interest within the images. Digital terrain mapping analysis performed in this work describe the crater geometry (shape, radius, and depth), eroded volume, volumetric erosion rate, and estimated mass erosion rate of the Hepburn, Sleepy Dragon, Burnside, and Goulburn craters. Crater depths ranged from five to ten centimeters deep influencing an area as wide as two meters in some cases. The craters formed were highly asymmetrical and generally oblong primarily due to the underlying bedrock formations underneath the surface. Comparison with ground tests performed at the NASA AMES Planetary Aeolian Laboratory (PAL) by Mehta showed good agreement with volumetric erosion rates and crater sizes of large particle soil simulants, providing validation to Earth based ground tests of Martian regolith.

  4. Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

    SciTech Connect

    Kuperman, R.G.

    1996-02-01

    Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

  5. Reactive transport controls on sandy acid sulfate soils and impacts on shallow groundwater quality

    NASA Astrophysics Data System (ADS)

    Salmon, S. Ursula; Rate, Andrew W.; Rengel, Zed; Appleyard, Steven; Prommer, Henning; Hinz, Christoph

    2014-06-01

    Disturbance or drainage of potential acid sulfate soils (PASS) can result in the release of acidity and degradation of infrastructure, water resources, and the environment. Soil processes affecting shallow groundwater quality have been investigated using a numerical code that integrates (bio)geochemical processes with water, solute, and gas transport. The patterns of severe and persistent acidification (pH < 4) in the sandy, carbonate-depleted podzols of a coastal plain could be reproduced without calibration, based on oxidation of microcrystalline pyrite after groundwater level decrease and/or residual groundwater acidity, due to slow vertical solute transport rates. The rate of acidification was limited by gas phase diffusion of oxygen and hence was sensitive to soil water retention properties and in some cases also to oxygen consumption by organic matter mineralization. Despite diffusion limitation, the rate of oxidation in sandy soils was rapid once pyrite-bearing horizons were exposed, even to a depth of 7.5 m. Groundwater level movement was thus identified as an important control on acidification, as well as the initial pyrite content. Increase in the rate of Fe(II) oxidation lead to slightly lower pH and greater accumulation of Fe(III) phases, but had little effect on the overall amount of pyrite oxidized. Aluminosilicate (kaolinite) dissolution had a small pH-buffering effect but lead to the release of Al and associated acidity. Simulated dewatering scenarios highlighted the potential of the model for risk assessment of (bio)geochemical impacts on soil and groundwater over a range of temporal and spatial scales.

  6. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  7. [Effect of low molecular weight organic acids on inorganic phosphorus transformation in red soil and its acidity].

    PubMed

    Hu, Hongqing; Liao, Lixia; Wang, Xinglin

    2002-07-01

    Red soil samples collected from southern Hubei province and northern Jiangxi province were tested to analyze their inorganic phosphorus fractions, pH and active aluminum after incubated with added various organic acids. The results indicated that application of organic acids increased the content of Ca2-P in both red soils, in the order of citric acid > malic acid > succinic acid > acetic acid, did not affect the contents of Ca8-P and Ca10-P, but usually reduced Fe-P, Al-P and O-P. The pH values of the soils treated by organic acids, except for acetic acid, were reduced by 0.65-1.96, compared with the control. Soil active Al extracted with 0.02 mol.L-1 CaCl2 in treatments with citric, malic and succinic acid was 5.7-51.3 times as the control, and Al extracted with 1 mol.L-1 KCl also increased 4.0-67.3 times. However, acetic acid had little influence on active soil Al. It was concluded that in red soils, organic acid could improve phosphorus availability, but enhance the soil toxicity caused by active Al.

  8. One strategy for estimating the potential soil carbon storage due to CO{sub 2} fertilization

    SciTech Connect

    Harrison, K.G.; Bonani, G.

    1994-06-01

    Soil radiocarbon measurements can be used to estimate soil carbon turnover rates and inventories. A labile component of soil carbon has the potential to respond to perturbations such as CO{sub 2} fertilization, changing climate, and changing land use. Soil carbon has influenced past and present atmospheric CO{sub 2} levels and will influence future levels. A model is used to calculate the amount of additional carbon stored in soil because of CO{sub 2} fertilization.

  9. Changes in soil carbon, nitrogen, and phosphorus due to land-use changes in Brazil

    NASA Astrophysics Data System (ADS)

    Groppo, J. D.; Lins, S. R. M.; Camargo, P. B.; Assad, E. D.; Pinto, H. S.; Martins, S. C.; Salgado, P. R.; Evangelista, B.; Vasconcellos, E.; Sano, E. E.; Pavão, E.; Luna, R.; Martinelli, L. A.

    2015-08-01

    In this paper, soil carbon, nitrogen and phosphorus concentrations and stocks were investigated in agricultural and natural areas in 17 plot-level paired sites and in a regional survey encompassing more than 100 pasture soils In the paired sites, elemental soil concentrations and stocks were determined in native vegetation (forests and savannas), pastures and crop-livestock systems (CPSs). Nutrient stocks were calculated for the soil depth intervals 0-10, 0-30, and 0-60 cm for the paired sites and 0-10, and 0-30 cm for the pasture regional survey by sum stocks obtained in each sampling intervals (0-5, 5-10, 10-20, 20-30, 30-40, 40-60 cm). Overall, there were significant differences in soil element concentrations and ratios between different land uses, especially in the surface soil layers. Carbon and nitrogen contents were lower, while phosphorus contents were higher in the pasture and CPS soils than in native vegetation soils. Additionally, soil stoichiometry has changed with changes in land use. The soil C : N ratio was lower in the native vegetation than in the pasture and CPS soils, and the carbon and nitrogen to available phosphorus ratio (PME) decreased from the native vegetation to the pasture to the CPS soils. In the plot-level paired sites, the soil nitrogen stocks were lower in all depth intervals in pasture and in the CPS soils when compared with the native vegetation soils. On the other hand, the soil phosphorus stocks were higher in all depth intervals in agricultural soils when compared with the native vegetation soils. For the regional pasture survey, soil nitrogen and phosphorus stocks were lower in all soil intervals in pasture soils than in native vegetation soils. The nitrogen loss with cultivation observed here is in line with other studies and it seems to be a combination of decreasing organic matter inputs, in cases where crops replaced native forests, with an increase in soil organic matter decomposition that leads to a decrease in the long

  10. Acidification of soil-water in low base-saturated sand soils of the superior uplands under acid and normal precipitation.

    PubMed

    Harris, A R

    1989-04-01

    now being analyzed for the 1986 treatment year. In leachate collected from the upper horizons of the soil colums, there was a significant difference in pH, alkalinity, nitrate, and sulfate concentrations between the pH 5.4 and pH 4.2 precipitation treatments. This difference, however, disappears at the bottom of the columns. This could be partly due to exchange reactions in the B horizon. The pH and alkalinities are higher in bottom leachate. Chloride and nitrate also increased significantly due mainly to concentrating effects. Even with a pickup of sulfate in the B horizon, sulfate adsorption decreased bottom leachate concentrations well below surface values.Alkalinity, pH, and sulfate concentration in the leachate decreased over the treatment season. Nitrate concentration increased by 4- to 5-fold over the season. Leachate from the bottom of the soil columns is becoming more acidic with time with negative alkalinities appearing more frequently in columns with soils of lower base saturation. There were some significant alkalinity differences due to humus treatments; however, these were not consistent between pH treatments, and need further study. This research will eventually answer whether soil processes can be important to the acidification of lakes in poor, sandy, outwash plains of the Superior Uplands, and whether a reduction in acid sulfate deposition will reverse the percolate alkalinity from negative to positive.

  11. [Effects of simulated acid rain on decomposition of soil organic carbon and crop straw].

    PubMed

    Zhu, Xue-Zhu; Huang, Yao; Yang, Xin-Zhong

    2009-02-01

    To evaluate the effects of acid rain on the organic carbon decomposition in different acidity soils, a 40-day incubation test was conducted with the paddy soils of pH 5.48, 6.70 and 8.18. The soils were amended with 0 and 15 g x kg(-1) of rice straw, adjusted to the moisture content of 400 g x kg(-1) air-dried soil by using simulated rain of pH 6.0, 4.5, and 3.0, and incubated at 20 degrees C. The results showed that straw, acid rain, and soil co-affected the CO2 emission from soil system. The amendment of straw increased the soil CO2 emission rate significantly. Acid rain had no significant effects on soil organic carbon decomposition, but significantly affected the straw decomposition in soil. When treated with pH 3.0 acid rain, the amount of decomposed straw over 40-day incubation in acid (pH 5.48) and alkaline (pH 8.18) soils was 8% higher, while that in neutral soil (pH 6.70) was 15% lower, compared to the treatment of pH 6.0 rain. In the treatment of pH 3.0 acid rain, the decomposition rate of soil organic C in acid (pH 5.48) soil was 43% and 50% (P < 0.05) higher than that in neutral (pH 6.70) and alkaline (pH 8.18) soils, while the decomposition rate of straw in neutral soil was 17% and 16% (P < 0.05) lower than that in acid and alkaline soils, respectively.

  12. Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

    NASA Astrophysics Data System (ADS)

    Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

    2014-05-01

    Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

  13. Effect of Short-Chain Fatty Acids and Soil Atmosphere on Tylenchorhynchus spp.

    PubMed Central

    McElderry, Claire F.; Browning, Marsha; Amador, José A.

    2005-01-01

    Short-chain fatty acids can be produced under anaerobic conditions by fermentative soil microbes and have nematicidal properties. We evaluated the effects of butyric and propionic acids on death and recovery of stunt nematodes (Tylenchorhynchus spp.), a common parasite of turfgrass. Nematodes in a sand-soil mix (80:20) were treated with butyric or propionic acid and incubated under air or N₂ for 7 days at 25 °C. Amendment of soil with 0.1 and 1.0 µmol (8.8 and 88 µg) butyric acid/g soil or 1.0 µmol (74 µg) propionic acid/g soil resulted in the death of all nematodes. The composition of the soil atmosphere had no effect on the nematicidal activity of the acids. Addition of hydrochloric acid to adjust soil pH to 4.4 and 3.5 resulted in nematode mortality relative to controls (41% to 86%) but to a lesser degree than short-chain fatty acids at the same pH. Nematodes did not recover after a 28-day period following addition of 10 µmol butyric acid/g soil under air or N₂. Carbon mineralization decreased during this period, whereas levels of inorganic N and microbial biomass-N remained constant. Short-chain fatty acids appear to be effective in killing Tylenchorhynchus spp. independent of atmospheric composition. Nematode mortality appears to be a function of the type and concentration of fatty acid and soil pH. PMID:19262845

  14. Perfluoroalkyl acid distribution in various plant compartments of edible crops grown in biosolids-amended soils.

    PubMed

    Blaine, Andrea C; Rich, Courtney D; Sedlacko, Erin M; Hundal, Lakhwinder S; Kumar, Kuldip; Lau, Christopher; Mills, Marc A; Harris, Kimberly M; Higgins, Christopher P

    2014-07-15

    Crop uptake of perfluoroalkyl acids (PFAAs) from biosolids-amended soil has been identified as a potential pathway for PFAA entry into the terrestrial food chain. This study compared the uptake of PFAAs in greenhouse-grown radish (Raphanus sativus), celery (Apium graveolens var. dulce), tomato (Lycopersicon lycopersicum), and sugar snap pea (Pisum sativum var. macrocarpon) from an industrially impacted biosolids-amended soil, a municipal biosolids-amended soil, and a control soil. Individual concentrations of PFAAs, on a dry weight basis, in mature, edible portions of crops grown in soil amended with PFAA industrially impacted biosolids were highest for perfluorooctanoate (PFOA; 67 ng/g) in radish root, perfluorobutanoate (PFBA; 232 ng/g) in celery shoot, and PFBA (150 ng/g) in pea fruit. Comparatively, PFAA concentrations in edible compartments of crops grown in the municipal biosolids-amended soil and in the control soil were less than 25 ng/g. Bioaccumulation factors (BAFs) were calculated for the root, shoot, and fruit compartments (as applicable) of all crops grown in the industrially impacted soil. BAFs were highest for PFBA in the shoots of all crops, as well as in the fruit compartment of pea. Root-soil concentration factors (RCFs) for tomato and pea were independent of PFAA chain length, while radish and celery RCFs showed a slight decrease with increasing chain length. Shoot-soil concentration factors (SCFs) for all crops showed a decrease with increasing chain length (0.11 to 0.36 log decrease per CF2 group). The biggest decrease (0.54-0.58 log decrease per CF2 group) was seen in fruit-soil concentration factors (FCFs). Crop anatomy and PFAA properties were utilized to explain data trends. In general, fruit crops were found to accumulate fewer long-chain PFAAs than shoot or root crops presumably due to an increasing number of biological barriers as the contaminant is transported throughout the plant (roots to shoots to fruits). These data were

  15. EDTA and HCl leaching of calcareous and acidic soils polluted with potentially toxic metals: remediation efficiency and soil impact.

    PubMed

    Udovic, Metka; Lestan, Domen

    2012-07-01

    The environmental risk of potentially toxic metals (PTMs) in soil can be diminished by their removal. Among the available remediation techniques, soil leaching with various solutions is one of the most effective but data about the impact on soil chemical and biological properties are still scarce. We studied the effect of two common leaching agents, hydrochloric acid (HCl) and a chelating agent (EDTA) on Pb, Zn, Cd removal and accessibility and on physico-chemical and biological properties in one calcareous, pH neutral soil and one non-calcareous acidic soil. EDTA was a more efficient leachant compared to HCl: up to 133-times lower chelant concentration was needed for the same percentage (35%) of Pb removal. EDTA and HCl concentrations with similar PTM removal efficiency decreased PTM accessibility in both soils but had different impacts on soil properties. As expected, HCl significantly dissolved carbonates from calcareous soil, while EDTA leaching increased the pH of the acidic soil. Enzyme activity assays showed that leaching with HCl had a distinctly negative impact on soil microbial and enzyme activity, while leaching with EDTA had less impact. Our results emphasize the importance of considering the ecological impact of remediation processes on soil in addition to the capacity for PTM removal.

  16. Transport of two naphthoic acids and salicylic acid in soil: experimental study and empirical modeling.

    PubMed

    Hanna, K; Lassabatere, L; Bechet, B

    2012-09-15

    In contrast to the parent compounds, the mechanisms responsible for the transport of natural metabolites of polycyclic aromatic hydrocarbons (PAH) in contaminated soils have been scarcely investigated. In this study, the sorption of three aromatic acids (1-naphthoic acid (NA), 1-hydroxy-2-naphthoic acid (HNA) and salicylic acid (SA)) was examined on soil, in a batch equilibrium single-system, with varying pH and acid concentrations. Continuous flow experiments were also carried out under steady-state water flow. The adsorption behavior of naphthoic and benzoic acids was affected by ligand functionality and molecular structure. All modeling options (equilibrium, chemical nonequilibrium, i.e. chemical kinetics, physical nonequilibrium, i.e. surface sites in the immobile water fraction, and both chemical and physical nonequilibrium) were tested in order to describe the breakthrough behavior of organic compounds in homogeneously packed soil columns. Tracer experiments showed a small fractionation of flow into mobile and immobile compartments, and the related hydrodynamic parameters were used for the modeling of reactive transport. In all cases, the isotherm parameters obtained from column tests differed from those derived from the batch experiments. The best accurate modeling was obtained considering nonequilibrium for the three organic compounds. Both chemical and physical nonequilibrium led to appropriate modeling for HNA and NA, while chemical nonequilibrium was the sole option for SA. SA sorption occurs mainly in mobile water and results from the concomitancy of instantaneous and kinetically limited sites. For all organic compounds, retention is contact condition dependent and differs between batch and column experiments. Such results show that preponderant mechanisms are solute dependent and kinetically limited, which has important implications for the fate and transport of carboxylated aromatic compounds in contaminated soils.

  17. Profiling of soil fatty acids using comprehensive two-dimensional gas chromatography with mass spectrometry detection.

    PubMed

    Zeng, Annie Xu; Chin, Sung-Tong; Patti, Antonio; Marriott, Philip J

    2013-11-22

    Profiling of phospholipid fatty acids (PLFA) represents a challenging goal for distinguishing the diversity of microbial communities and biomass in the complex and heterogeneous soil ecosystem. Comprehensive two-dimensional gas chromatography (GC×GC) coupled with simultaneous flame ionisation and mass spectrometry detection was applied as a culture-independent method for PLFA profiling of microbial classification in forest soil. A number of column sets were evaluated for the GC×GC separation of fatty acid methyl esters (FAME). Due to better isomeric separation and compound patterns on the 2D contour plot, an apolar-polar column combination was selected for soil microbial PLFA characterisation. A comprehensive view of PLFA composition with carbon chain length varying from 12 to 20 was observed in forest soil samples, with the commonly reported bacterial FAME of iso-/anteiso-, methyl-branched-, cyclopropyl-, and hydroxyl-substituted FA identified by their mass spectral and retention time according to authentic standards. Notably, some uncommon oxygenated FAME were found in high abundance and were further characterised by GC×GC coupled with high resolution mass spectrometry. This tentatively revealed geometric pairs of methyl 9,10-epoxyoctadecanoate isomers.

  18. Influences of humic acid and fulvic acid on horizontal leaching behavior of anthracene in soil barriers.

    PubMed

    Yu, Sheng; Li, Bang-Yu; Chen, Yi-Hu

    2015-12-01

    The influences of humic acid (HA) and fulvic acid (FA) on horizontal leaching behaviors of anthracene in barriers were investigated. Soil colloids (≤1 μm) were of concern because of their abilities of colloid-facilitated transport for hydrophobic organic compounds with soluble and insoluble organic matters. Through freely out of the barriers in the presence of soil colloids with FA added, the higher concentrations of anthracene were from 320 μg L(-1) (D1 and D3) to 390 μg L(-1) (D2 and D4) with 1 to 20 cm in length. The contents of anthracene were distributed evenly at 25 ng g(-1) dry weight (DW) (D1 and D3) and 11 ng g(-1) DW (D2 and D4) in barriers. Therefore, anthracene leaching behaviors were mainly induced by soil colloids with soluble organic matters. The insoluble organic matters would facilitate anthracene onto soil colloids and enhance the movement in and through porous media of soil matrix.

  19. Formation of diphenylthioarsinic acid from diphenylarsinic acid under anaerobic sulfate-reducing soil conditions.

    PubMed

    Hisatomi, Shihoko; Guan, Ling; Nakajima, Mami; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2013-11-15

    Diphenylarsinic acid (DPAA) is a toxic phenylarsenical compound often found around sites contaminated with phenylarsenic chemical warfare agents, diphenylcyanoarsine or diphenylchloroarsine, which were buried in soil after the World Wars. This research concerns the elucidation of the chemical structure of an arsenic metabolite transformed from DPAA under anaerobic sulfate-reducing soil conditions. In LC/ICP-MS analysis, the retention time of the metabolite was identical to that of a major phenylarsenical compound synthesized by chemical reaction of DPAA and hydrogen sulfide. Moreover the mass spectra for the two compounds measured using LC/TOF-MS were similar. Subsequent high resolution mass spectral analysis indicated that two major ions at m/z 261 and 279, observed on both mass spectra, were attributable to C12H10AsS and C12H12AsSO, respectively. These findings strongly suggest that the latter ion is the molecular-related ion ([M+H](+)) of diphenylthioarsinic acid (DPTA; (C6H5)2AsS(OH)) and the former ion is its dehydrated fragment. Thus, our results reveal that DPAA can be transformed to DPTA, as a major metabolite, under sulfate-reducing soil conditions. Moreover, formation of diphenyldithioarsinic acid and subsequent dimerization were predicted by the chemical reaction analysis of DPAA with hydrogen sulfide. This is the first report to elucidate the occurrence of DPAA-thionation in an anaerobic soil.

  20. A Simulation of the Interaction of Acid Rain with Soil Minerals

    ERIC Educational Resources Information Center

    Schilling, Amber L.; Hess, Kenneth R.; Leber, Phyllis A.; Yoder, Claude H.

    2004-01-01

    The atmospheric issue of acid rains is subjected to a five-part laboratory experiment by concentrating on the chemistry of the infiltration process of acid rainwater through soils. This procedure of quantitative scrutiny helps students realize the efficacy of soil minerals in the consumption of surplus acidity in rainwater.

  1. Influence of multi-step washing using Na2EDTA, oxalic acid and phosphoric acid on metal fractionation and spectroscopy characteristics from contaminated soil.

    PubMed

    Wei, Meng; Chen, Jiajun

    2016-11-01

    A multi-step soil washing test using a typical chelating agent (Na2EDTA), organic acid (oxalic acid), and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated with heavy metals near an arsenic mining area. The aim of the test was to improve the heavy metal removal efficiency and investigate its influence on metal fractionation and the spectroscopy characteristics of contaminated soil. The results indicated that the orders of the multi-step washing were critical for the removal efficiencies of the metal fractions, bioavailability, and potential mobility due to the different dissolution levels of mineral fractions and the inter-transformation of metal fractions by XRD and FT-IR spectral analyses. The optimal soil washing options were identified as the Na2EDTA-phosphoric-oxalic acid (EPO) and phosphoric-oxalic acid-Na2EDTA (POE) sequences because of their high removal efficiencies (approximately 45 % for arsenic and 88 % for cadmium) and the minimal harmful effects that were determined by the mobility and bioavailability of the remaining heavy metals based on the metal stability (I R ) and modified redistribution index ([Formula: see text]).

  2. Suicide case due to phosphoric acid ingestion: case report and review of literature.

    PubMed

    Aquila, Isabella; Pepe, Francesca; Di Nunzio, Ciro; Ausania, Francesco; Serra, Arianna; Ricci, Pietrantonio

    2014-11-01

    Ingesting caustic substances represents a common event which may result in serious injuries of the gastrointestinal system. Severity of injury depends on the type of ingested substance: Caustic burns are more frequently associated with acid ingestion and their severity depends on type, concentration, time of exposure, and amount of the ingested substance. We report a case of phosphoric acid ingestion leading to death in a patient with depressive disorder. While reports ingestion of other acids and organophosphates can be found in the literature, there are no reports detailing a death due to phosphoric acid ingestion. We hope that presenting the findings in this case can aid death investigators in future cases that may involve ingestion of such a substance. After autopsy pH, phosphate and calcium ions concentration in the blood were analyzed. The cause of death was due to systemic effects: metabolic acidosis, hypophosphatemia, hypocalcemia, and hyperkalemia.

  3. Formation of chloroacetic acids from soil, humic acid and phenolic moieties.

    PubMed

    Fahimi, I J; Keppler, F; Schöler, H F

    2003-07-01

    The mechanism of formation of chloroacetates, which are important toxic environmental substances, has been controversial. Whereas the anthropogenic production has been well established, a natural formation has also been suggested. In this study the natural formation of chloroacetic acids from soil, as well as from humic material which is present in soil and from phenolic model substances has been investigated. It is shown that chloroacetates are formed from humic material with a linear relationship between the amount of humic acid used and chloroacetates found. More dichloroacetate (DCA) than trichloroacetate (TCA) is produced. The addition of Fe(2+), Fe(3+) and H(2)O(2) leads to an increased yield. NaCl was added as a source of chloride. We further examined the relationship between the structure and reactivity of phenolic substances, which can be considered as monomeric units of humic acids. Ethoxyphenol with built-in ethyl groups forms large amounts of DCA and TCA. The experiments with phenoxyacetic acid yielded large amounts of monochloroacetate (MCA). With other phenolic substances a ring cleavage was observed. Our investigations indicate that chloroacetates are formed abiotically from humic material and soils in addition to their known biotic mode of formation.

  4. Root-secreted malic acid recruits beneficial soil bacteria.

    PubMed

    Rudrappa, Thimmaraju; Czymmek, Kirk J; Paré, Paul W; Bais, Harsh P

    2008-11-01

    Beneficial soil bacteria confer immunity against a wide range of foliar diseases by activating plant defenses, thereby reducing a plant's susceptibility to pathogen attack. Although bacterial signals have been identified that activate these plant defenses, plant metabolites that elicit rhizobacterial responses have not been demonstrated. Here, we provide biochemical evidence that the tricarboxylic acid cycle intermediate L-malic acid (MA) secreted from roots of Arabidopsis (Arabidopsis thaliana) selectively signals and recruits the beneficial rhizobacterium Bacillus subtilis FB17 in a dose-dependent manner. Root secretions of L-MA are induced by the foliar pathogen Pseudomonas syringae pv tomato (Pst DC3000) and elevated levels of L-MA promote binding and biofilm formation of FB17 on Arabidopsis roots. The demonstration that roots selectively secrete L-MA and effectively signal beneficial rhizobacteria establishes a regulatory role of root metabolites in recruitment of beneficial microbes, as well as underscores the breadth and sophistication of plant-microbial interactions.

  5. LEAD IMMOBILIZATION TECHNOLOGY UTILIZING POTASSIUM DEHYDROGEN PHOSPHATE AND ORGANIC ACID IN AN ACTUAL SHOOTING RANGE LEAD-CONTAMINATED SOIL

    NASA Astrophysics Data System (ADS)

    Yoshida, Takatoshi; Katoh, Masahiko; Sato, Takeshi

    This paper addressed potassium dehydrogen phosphate (KP) and acetic acid (OAc) amendments of neutral pH soil sampled from the lead contaminated soil in a shooting range to promote immobilization by modification of Pb speciation in solid and liquid phases. This study evaluated the amount of antimony leachability in the so il. The single KP application increased Pb and Sb leachabilitie s due to soil pH increase, wheres combined KP and OAc amendments decreased them in compar ison with the control. Sequential extraction analysis reveal ed that Pb residual fraction in KP amended soil increased to 72% than that in the control (5%). Th e residual fraction (82%) in KP an d OAc amended soil was higher than the single application of KP. This st udy indicated that combined appli catons of KP and OAc promoted Pb immobilization and suppressed Pb leachabilities.

  6. [Effect of acetic acid on adsorption of acid phosphatase by some soil colloids and clay minerals].

    PubMed

    Zhao, Zhenhua; Huang, Qiaoyun; Jiang, Xin; Yu, Guifen; Wang, Fang; Li, Xueyuan

    2004-03-01

    This paper studied the effect of acetic acid with different concentrations and pH values on the adsorption of acid phosphatase by some soil colloids and clay minerals (SCCM). The results showed that the pH values for the maximum adsorption of the enzyme were between the IEP of the enzyme and the PZC of SCCM. In the acetic acid systems, the amount of the enzyme adsorbed by SCCM was in the order of goethite > yellow brown soil > latosol > kaolinite > delta-MnO2. A remarkable influence of acetic acid concentration on the adsorption amount and the binding energy of the enzyme was observed. With the increase of the concentration from 0 to 200 mmol.L-1 in the system, acetic acid exhibited an enhanced effect, followed by an inhibition action on the adsorption of the enzyme on SCCM. The changes of the binding energy (K value) for the enzyme on SCCM were on the contrary to those of the maximum adsorption. The possible mechanisms for the influence of acetic acid on the adsorption of enzyme by SCCM were also discussed.

  7. Immobilization of Zn, Cu, and Pb in contaminated soils using phosphate rock and phosphoric acid.

    PubMed

    Cao, Xinde; Wahbi, Ammar; Ma, Lena; Li, Bing; Yang, Yongliang

    2009-05-30

    Considerable research has been done on P-induced Pb immobilization in Pb-contaminated soils. However, application of P to soils contaminated with multiple heavy metals is limited. The present study examined effectiveness of phosphoric acid (PA) and/or phosphate rock (PR) in immobilizing Pb, Cu, and Zn in two contaminated soils. The effectiveness was evaluated using water extraction, plant uptake, and a simple bioaccessibility extraction test (SBET) mimicking metal uptake in the acidic environment of human stomach. The possible mechanisms for metal immobilization were elucidated using X-ray diffraction, scanning electron microscopy, and chemical speciation program Visual MINTEQ. Compared to the control, all P amendments significantly reduced Pb water solubility, phytoavailability, and bioaccessibility by 72-100%, 15-86%, and 28-92%, respectively. The Pb immobilization was probably attributed to the formation of insoluble Pb phosphate minerals. Phosphorus significantly reduced Cu and Zn water solubility by 31-80% and 40-69%, respectively, presumably due to their sorption on minerals (e.g., calcite and phosphate phases) following CaO addition. However, P had little effect on the Cu and Zn phytoavailability; while the acid extractability of Cu and Zn induced by SBET (pH 2) were even elevated by up to 48% and 40%, respectively, in the H(3)PO(4) treatments (PA and PR+PA). Our results indicate that phosphate was effective in reducing Pb availability in terms of water solubility, bioaccessibility, and phytoavailability. Caution should be exercised when H(3)PO(4) was amended to the soil co-contaminated with Cu and Zn since the acidic condition of SBET increased Cu and Zn bioaccessibility though their water solubility was reduced.

  8. Omaha Soil Mixing Study: Redistribution of Lead in Remediated Residential Soils Due to Excavation or Homeowner Disturbance.

    EPA Science Inventory

    Urban soils within the Omaha Lead Superfund Site have been contaminated with lead (Pb) from atmospheric deposition of particulate materials from lead smelting and recycling activities. In May of 2009 the Final Record of Decision stated that any residential soil exceeding the pre...

  9. Enhanced biodegradation of anthracene in acidic soil by inoculated Burkholderia sp. VUN10013.

    PubMed

    Somtrakoon, Khanitta; Suanjit, Sudarat; Pokethitiyook, Prayad; Kruatrachue, Maleeya; Lee, Hung; Upatham, Suchart

    2008-08-01

    The ability of Burkholderia sp. VUN10013 to degrade anthracene in microcosms of two acidic Thai soils was studied. The addition of Burkholderia sp. VUN10013 (initial concentration of 10(5) cells g(-1) dry soil) to autoclaved soil collected from the Plew District, Chanthaburi Province, Thailand, supplemented with anthracene (50 mg kg(-1) dry soil) resulted in complete degradation of the added anthracene within 20 days. In contrast, under the same test conditions but using autoclaved soil collected from the Kitchagude District, Chanthaburi Province, Thailand, only approximately 46.3% of the added anthracene was degraded after 60 days of incubation. In nonautoclaved soils, without adding the VUN10013 inocula, 22.8 and 19.1% of the anthracene in Plew and Kitchagude soils, respectively, were degraded by indigenous bacteria after 60 days. In nonautoclaved soil inoculated with Burkholderia sp. VUN10013, the rate and extent of anthracene degradation were considerably better than those seen in autoclaved soils or in uninoculated nonautoclaved soils in that only 8.2 and 9.1% of anthracene remained in nonautoclaved Plew and Kitchagude soils, respectively, after 10 days of incubation. The results showed that the indigenous microorganisms in the pristine acidic soils have limited ability to degrade anthracene. Inoculation with the anthracene-degrading Burkholderia sp. VUN10013 significantly enhanced anthracene degradation in such acidic soils. The indigenous microorganisms greatly assisted the VUN10013 inoculum in anthracene degradation, especially in the more acidic Kitchagude soil.

  10. pH-Dependent sorption of acidic organic chemicals to soil organic matter.

    PubMed

    Tülp, Holger C; Fenner, Kathrin; Schwarzenbach, René P; Goss, Kai-Uwe

    2009-12-15

    Due to their increased polarity, many contemporary biologically active chemicals exhibit acid functions and may thus dissociate to their anionic conjugated base at pH values typically present in the environment. Despite its negative charge, soil organic matter (SOM) has been demonstrated to be the main sorbent in soils, even for the anionic species of organic acids. Nevertheless, few data exist that allow for a systematic interpretation of the sorption of organic acids into SOM. Therefore, in this study, the sorption of the neutral and anionic species of 32 diverse organic acids belonging to nine different chemical groups to SOM was investigated. Partition coefficients were determined from HPLC retention volumes on a column packed with peat, at three Ca(2+)-concentrations and over a pH range of 4.5-7.5. The influence of Ca(2+)-concentrations on anion sorption was small (factor 2 in the usual environmental Ca(2+)-concentration range) and independent of molecular structure. Generally, the organic carbon-water partition coefficients, K(oc), of both the neutral and anionic species increased with increasing molecular size and decreased with increasing polarity. At an environmentally relevant Ca(2+)-concentration of 10 mM, the investigated anions sorbed between a factor of 7-60 less than the corresponding neutral acid. This factor was more homogeneous within a group of structurally related compounds. These results indicate that while similar nonionic interactions seem to govern the partitioning of both the neutral and anionic species into SOM, the electrostatic interactions of the anionic species with SOM are a complex and currently not well understood function of the type of acidic functional group. The HPLC-based, flow through method presented in this study was shown to yield consistent results for a wide range of organic acids in a high-throughput manner. It should therefore prove highly useful in further investigating how different acidic functional groups affect

  11. Acute renal failure and metabolic acidosis due to oxalic acid intoxication: a case report.

    PubMed

    Yamamoto, Rie; Morita, Seiji; Aoki, Hiromichi; Nakagawa, Yoshihide; Yamamoto, Isotoshi; Inokuchi, Sadaki

    2011-12-20

    Most of the reports of oxalic acid intoxication are in cases of ethylene glycol intoxication. These symptoms are known to be central nerve system manifestations, cardiopulmonary manifestations and acute renal failure. There have been only a few reports of direct oxalic acid intoxication. However, there have been a few recent reports of oxalic acid intoxication due to the ingestion of star fruit and ascorbic acid. We herein report the case of a patient with acute renal failure and metabolic acidosis caused directly by consumption of oxalic acid. During the initial examination by the physician at our hospital, the patient presented with tachypnea, a precordinal burning sensation, nausea and metabolic acidosis. After admission, the patient developed renal failure and anion gap high metabolic acidosis, but did not develop any CNS or cardio-pulmonary manifestations in the clinical course. The patient benefitted symptomatically from hemodialysis.

  12. The influence of organic acids in relation to acid deposition in controlling the acidity of soil and stream waters on a seasonal basis.

    PubMed

    Chapman, Pippa J; Clark, Joanna M; Reynolds, Brian; Adamson, John K

    2008-01-01

    Much uncertainty still exists regarding the relative importance of organic acids in relation to acid deposition in controlling the acidity of soil and surface waters. This paper contributes to this debate by presenting analysis of seasonal variations in atmospheric deposition, soil solution and stream water chemistry for two UK headwater catchments with contrasting soils. Acid neutralising capacity (ANC), dissolved organic carbon (DOC) concentrations and the Na:Cl ratio of soil and stream waters displayed strong seasonal patterns with little seasonal variation observed in soil water pH. These patterns, plus the strong relationships between ANC, Cl and DOC, suggest that cation exchange and seasonal changes in the production of DOC and seasalt deposition are driving a shift in the proportion of acidity attributable to strong acid anions, from atmospheric deposition, during winter to predominantly organic acids in summer.

  13. Lactobacillus plantarum phytase activity is due to non-specific acid phosphatase.

    PubMed

    Zamudio, M; González, A; Medina, J A

    2001-03-01

    Microbial phytases suitable for food fermentations could be obtained from lactic acid bacteria isolated from natural vegetable fermentations. Phytase activity was evaluated for six lactic acid bacteria cultures. Although the highest activity was found for Lactobacillus plantarum, the phytase activity was very low. Further characterization of the enzyme with phytate-degrading activity showed a molecular weight of 52 kDa and an optimum activity at pH 5.5 and 65 degrees C. Enzyme activity was due to a non-specific acid phosphatase which had a higher hydrolysis rate with monophosphorylated compounds such as acetyl phosphate that could explain the low phytase activity.

  14. Evaluation of the Morpho-physiology characteristics of maize inbred lines introduced from CIMMYT to identify the best candidates for planting in acidic soil in Jasinga, Indonesia

    NASA Astrophysics Data System (ADS)

    Lubis, K.; Sutjahjo, S. H.; Syukur, M.; Trikoesoemaningtyas

    2016-08-01

    Technological developments and climate change have affected crop planting strategies. For example, maize production has expanded to sub-optimal lands, including acidic soil common in areas like Indonesia. Breeding programs have created inbred lines of maize introduced from CIMMYT; they were tested locally in acidic soils to determine their adaptability and tolerance mechanisms. Breeds CLA 46 and NEI 9008 were found to be excellent candidates for acidic soil due to their ASI, high number of grains per year, and suitable dry seed weight.

  15. Extraction of amino acids from soils and sediments with superheated water

    NASA Technical Reports Server (NTRS)

    Cheng, C. N.; Ponnamperuma, C.

    1974-01-01

    A method of extraction for amino acids from soils and sediments involving superheated water has been investigated. About 75-97 per cent of the amino acids contained in four soils of a soil profile from Illinois were extracted by this method. Deep penetration of water into soil aggregates and partial hydrolysis of peptide bonds during this extraction by water at high temperature are likely mechanisms responsible for the release of amino acids from samples. This extraction method does not require subsequent desalting treatments when analyses are carried out with an ion-exchange amino acid analyzer.

  16. Changes in soil carbon, nitrogen and phosphorus due to land-use changes in Brazil

    NASA Astrophysics Data System (ADS)

    Groppo, J. D.; Lins, S. R. M.; Camargo, P. B.; Assad, E. D.; Pinto, H. S.; Martins, S. C.; Salgado, P. R.; Evangelista, B.; Vasconcellos, E.; Sano, E. E.; Pavão, E.; Luna, R.; Martinelli, L. A.

    2015-02-01

    In this paper soil carbon, nitrogen and phosphorus concentrations and related elemental ratios, as well as and nitrogen and phosphorus stocks were investigated in 17 paired sites and in a regional survey encompassing more than 100 pasture soils in the Cerrado, Atlantic Forest, and Pampa, the three important biomes of Brazil. In the paired sites, elemental soil concentrations and stocks were determined in native vegetation, pastures and crop-livestock systems (CPS). Overall, there were significant differences in soil element concentrations and ratios between different land uses, especially in the surface soil layers. Carbon and nitrogen contents were lower, while phosphorus contents were higher in the pasture and CPS soils than in forest soils. Additionally, soil stoichiometry has changed with changes in land use. The soil C : N ratio was lower in the forest than in the pasture and CPS soils; and the carbon and nitrogen to available phosphorus ratio (PME) decreased from the forest to the pasture to the CPS soils. The average native vegetation soil nitrogen stocks at 0-10, 0-30 and 0-60 cm soil depth layers were equal to approximately 2.3, 5.2, 7.3 Mg ha-1, respectively. In the paired sites, nitrogen loss in the CPS systems and pasture soils were similar and equal to 0.6, 1.3 and 1.5 Mg ha-1 at 0-10, 0-30 and 0-60 cm soil depths, respectively. In the regional pasture soil survey, nitrogen soil stocks at 0-10 and 0-30 soil layers were equal to 1.6 and 3.9 Mg ha-1, respectively, and lower than the stocks found in the native vegetation of paired sites. On the other hand, the soil phosphorus stocks were higher in the CPS and pasture of the paired sites than in the soil of the original vegetation. The original vegetation soil phosphorus stocks were equal to 11, 22, and 43 kg ha-1 in the three soil depths, respectively. The soil phosphorus stocks increased in the CPS systems to 30, 50, and 63 kg ha-1, respectively, and in the pasture pair sites to 22, 47, and 68 kg ha-1

  17. Monitoring and assessment of surface water acidification following rewetting of oxidised acid sulfate soils.

    PubMed

    Mosley, Luke M; Zammit, Benjamin; Jolley, Ann-Marie; Barnett, Liz; Fitzpatrick, Rob

    2014-01-01

    Large-scale exposure of acid sulfate soils during a hydrological drought in the Lower Lakes of South Australia resulted in acidification of surface water in several locations. Our aim was to describe the techniques used to monitor, assess and manage these acidification events using a field and laboratory dataset (n = 1,208) of acidic to circum-neutral pH water samples. The median pH of the acidified (pH < 6.5) samples was 3.8. Significant (p < 0.05) increases in soluble metals (Al, Co, Mn, Ni and Zn above guidelines for ecosystem protection), SO4 (from pyrite oxidation), Si (from aluminosilicate dissolution) and Ca (from carbonate dissolution and limestone addition), were observed under the acidic conditions. The log of the soluble metal concentrations, acidity and SO4/Cl ratio increased linearly with pH. The pH, alkalinity and acidity measurements were used to inform aerial limestone dosing events to neutralise acidic water. Field measurements correlated strongly with laboratory measurements for pH, alkalinity and conductivity (r (2) ≥ 0.97) but only moderately with acidity (r (2) = 0.54), which could be due to difficulties in determining the indicator-based field titration endpoint. Laboratory measured acidity correlated well with calculated acidity (r (2) = 0.87, acidity present as Al(III) > H(+) ≈ Mn(II) > Fe(II/III)) but was about 20 % higher on average. Geochemical speciation calculations and XRD measurements indicated that solid phase minerals (schwertmannite and jarosite for Fe and jurbanite for Al) were likely controlling dissolved metal concentrations and influencing measured acidity between pH 2 and 5.

  18. Adsorption and desorption kinetics of carbofuran in acid soils.

    PubMed

    Bermúdez-Couso, Alipio; Fernández-Calviño, David; Pateiro-Moure, Miriam; Nóvoa-Muñoz, Juan Carlos; Simal-Gándara, Jesús; Arias-Estévez, Manuel

    2011-06-15

    Carbofuran adsorption and desorption were investigated in batch and stirred flow chamber (SFC) tests. The carbofuran adsorption capacity of the soils was found to be low and strongly dependent on their clay and organic carbon contents. Carbofuran sorption was due mainly (>80%) to fast adsorption processes governed by intraparticle diffusion. The adsorption kinetic constant for the pesticide ranged from 0.047 to 0.195 min(-1) and was highly correlated with constant n in the Freundlich equation (r=0.965, P<0.05). Batch tests showed carbofuran desorption to be highly variable and negatively correlated with eCEC and the clay content. The SFC tests showed that soil organic carbon (C) plays a key role in the irreversibility of carbofuran adsorption. Carbofuran desorption increased rapidly at C contents below 4%. The desorption kinetic constant for the compound (0.086-0.195 min(-1)) was generally higher than its adsorption kinetic constant; therefore, carbofuran is more rapidly desorbed than it is adsorbed in soil.

  19. Irreversibility of 2,4-Dichlorophenoxyacetic Acid Sorption onto a Volcanic Ash Soil

    NASA Astrophysics Data System (ADS)

    Mon, E.; Kawamoto, K.; Komatsu, T.; Moldrup, P.

    2008-12-01

    Pesticide sorption and desorption in soils are key processes governing fate and transport of pesticides in the soil environment. The irreversibility (or hysteresis) in the processes of pesticide sorption and desorption needs to be known to accurately predict behavior of pesticides in soil systems. 2,4-dichlorophenoxyacetic acid (2,4-D) is a widely used pesticide in agriculture fields. However, only few studies of 2,4-D adsorption onto Andosols (volcanic ash soils) have been published, and the knowledge of 2,4-D desorption onto Andosols is very limited. In this study, a volcanic ash soil sampled from a pasture site in Nishi-Tokyo, Japan was used as a sorbent in order to investigate the irreversibility of 2,4-D sorption. For comparison, a pure clay mineral (kaolinite) obtained from Clay Science Society of Japan (CSSJ) was also used. 2,4-D solutions with three concentrations (0.011, 0.022 and 0.045 mmol/L) were prepared in artificial rain water (ARW= 0.085mM NaCl + 0.015mM CaCl2) to simulate field conditions. To prepare the sample solutions, the solid mass/liquid volume ratio of 1:10 was used for both sorbents (volcanic ash soil and kaolinite). The experiments were conducted in triplicate using a batch method under different pH conditions to examine the effect of pH. Desorption was measured during a equilibration procedure: After removal of 7 mL of supernatant in the sorption step, 7 mL of ARW excluding 2,4-D was added to the sample solution after which, it was equilibrated and centrifuged. The procedure was performed sequentially three or four times to obtain a desorption isotherm. Sorption and desorption generally followed Freundlich isotherms. The results showed markedly effects of pH on 2,4-D sorption and desorption in both the soil and kaolinite, with the percentage of sorption increasing with decreasing pH whereas the percentage of desorption decreased. There was a larger adsorption-desorption hysteresis in the volcanic ash soil as compared to kaolinite

  20. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS II: OPTIMIZATION OF CHROMATOGRAPHY AND EXTRACTION

    EPA Science Inventory

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorinated octanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary p...

  1. The Effects of Various Amendments on Trace Element Stabilization in Acidic, Neutral, and Alkali Soil with Similar Pollution Index.

    PubMed

    Kim, Min-Suk; Min, Hyun-Gi; Lee, Sang-Hwan; Kim, Jeong-Gyu

    2016-01-01

    Many studies have examined the application of soil amendments, including pH change-induced immobilizers, adsorbents, and organic materials, for soil remediation. This study evaluated the effects of various amendments on trace element stabilization and phytotoxicity, depending on the initial soil pH in acid, neutral, and alkali conditions. As in all types of soils, Fe and Ca were well stabilized on adsorption sites. There was an effect from pH control or adsorption mechanisms on the stabilization of cationic trace elements from inorganic amendments in acidic and neutral soil. Furthermore, acid mine drainage sludge has shown great potential for stabilizing most trace elements. In a phytotoxicity test, the ratio of the bioavailable fraction to the pseudo-total fraction significantly affected the uptake of trace elements by bok choy. While inorganic amendments efficiently decreased the bioavailability of trace elements, significant effects from organic amendments were not noticeable due to the short-term cultivation period. Therefore, the application of organic amendments for stabilizing trace elements in agricultural soil requires further study.

  2. The Effects of Various Amendments on Trace Element Stabilization in Acidic, Neutral, and Alkali Soil with Similar Pollution Index

    PubMed Central

    Kim, Min-Suk; Min, Hyun-Gi; Lee, Sang-Hwan; Kim, Jeong-Gyu

    2016-01-01

    Many studies have examined the application of soil amendments, including pH change-induced immobilizers, adsorbents, and organic materials, for soil remediation. This study evaluated the effects of various amendments on trace element stabilization and phytotoxicity, depending on the initial soil pH in acid, neutral, and alkali conditions. As in all types of soils, Fe and Ca were well stabilized on adsorption sites. There was an effect from pH control or adsorption mechanisms on the stabilization of cationic trace elements from inorganic amendments in acidic and neutral soil. Furthermore, acid mine drainage sludge has shown great potential for stabilizing most trace elements. In a phytotoxicity test, the ratio of the bioavailable fraction to the pseudo-total fraction significantly affected the uptake of trace elements by bok choy. While inorganic amendments efficiently decreased the bioavailability of trace elements, significant effects from organic amendments were not noticeable due to the short-term cultivation period. Therefore, the application of organic amendments for stabilizing trace elements in agricultural soil requires further study. PMID:27835687

  3. Effects of surfactants on low-molecular-weight organic acids to wash soil zinc.

    PubMed

    Chen, Yue; Zhang, Shirong; Xu, Xiaoxun; Yao, Ping; Li, Ting; Wang, Guiyin; Gong, Guoshu; Li, Yun; Deng, Ouping

    2016-03-01

    Soil washing is an effective approach to the removal of heavy metals from contaminated soil. In this study, the effects of the surfactants sodium dodecyl sulfate, Triton X-100, and non-ionic polyacrylamide (NPAM) on oxalic acid, tartaric acid, and citric acid used to remove zinc from contaminated soils were investigated. The Zn removal efficiencies of all washing solutions showed a logarithmic increase with acid concentrations from 0.5 to 10.0 g/L, while they decreased as pH increased from 4 to 9. Increasing the reaction time enhanced the effects of surfactants on Zn removal efficiencies by the acids during washing and significantly (P < 0.05) improved the removal under some mixed cases. Oxalic acid suffered antagonistic effects from the three surfactants and seriously damaged soil nutrients during the removal of soil Zn. Notably, the three surfactants caused synergistic effects on tartaric and citric acid during washing, with NPAM leading to an increase in Zn removal by 5.0 g/L citric acid of 10.60 % (P < 0.05) within 2 h. NPAM also alleviated the loss of cation exchange capacity of washed soils and obviously improved soil nitrogen concentrations. Overall, combining citric acid with NPAM offers a promising approach to the removal of zinc from contaminated soil.

  4. Metagenomic analysis of the rhizosphere soil microbiome with respect to phytic acid utilization.

    PubMed

    Unno, Yusuke; Shinano, Takuro

    2013-01-01

    While phytic acid is a major form of organic phosphate in many soils, plant utilization of phytic acid is normally limited; however, culture trials of Lotus japonicus using experimental field soil that had been managed without phosphate fertilizer for over 90 years showed significant usage of phytic acid applied to soil for growth and flowering and differences in the degree of growth, even in the same culture pot. To understand the key metabolic processes involved in soil phytic acid utilization, we analyzed rhizosphere soil microbial communities using molecular ecological approaches. Although molecular fingerprint analysis revealed changes in the rhizosphere soil microbial communities from bulk soil microbial community, no clear relationship between the microbiome composition and flowering status that might be related to phytic acid utilization of L. japonicus could be determined. However, metagenomic analysis revealed changes in the relative abundance of the classes Bacteroidetes, Betaproteobacteria, Chlorobi, Dehalococcoidetes and Methanobacteria, which include strains that potentially promote plant growth and phytic acid utilization, and some gene clusters relating to phytic acid utilization, such as alkaline phosphatase and citrate synthase, with the phytic acid utilization status of the plant. This study highlights phylogenetic and metabolic features of the microbial community of the L. japonicus rhizosphere and provides a basic understanding of how rhizosphere microbial communities affect the phytic acid status in soil.

  5. Biogenic arsenic volatilisation from an acidic wetland soil

    NASA Astrophysics Data System (ADS)

    Ilgen, Gunter; Huang, Jen-How; Lu, Shipeng; Tian, Liyan; Alewell, Christine

    2014-05-01

    Biogenic arsenic (As) volatilisation was budgeted at 26000 t yr-1as the largest input of the global As release into the atmosphere, thereby playing an important role in the biogeochemical cycle of As in the surface environment. In order to quantify As volatilisation from wetland soils and to elucidate the geochemical and microbiological factors governing As volatilisation, a series of incubations with an acidic wetland soil collected in NE-Bavaria in Germany were performed at 15oC for 4 months with addition of NaN3, arsenite (As(III)), FeCl3, NaSO4 and NaOAc with N2 and air in the headspace. Speciation of gaseous As in the headspace using GC-ICP-MS/ ESI-MS coupling showed the predominance of either arsine (AsH3) or trimethylarsine ((CH3)3As) in all treatments during the time course of incubation. Monomethylarsine ((CH3)AsH2) and dimethylarsine ((CH3)2AsH) could be only detected in trace amounts. Arsenic speciation in porewater with HPLC-ICP-MS revealed the predominance of As(III) and methylated As was never detectable. Arsenic volatilisation summed to 2.3 ng As (88% as AsH3) in the control incubations, which accounted for ~0.25 % of the total As storage in the wetland soil. Treatments with 10 mM NaN3 resulted in emission of only 0.03 ng As. In contrast, addition of 10 mM NaOAc stimulated microbial activities in wetland soils and subsequently rose As volatilisation to 8.5 ng As. It could be therefore concluded that As volatilisation from the wetland soils was mainly biological. Spiking 67 μM As(III) increased 10 times of As volatilisation and the proportion of methylated arsines increased to 66%, which is supposed to be caused by the largely enhanced As availability in porewater for microbes (480 ppb, ~65 times higher than those in the controls). Adding 10 mM FeCl3 stimulated microbial Fe(III) reducing activities but suppressed other microbial activities by lowering soil pH from 5 to 3.6, decreasing consequently As volatilisation to 0.3 ng As. The much lower redox

  6. Phytoremediation of uranium-contaminated soils: Role of organic acids in triggering uranium hyperaccumulation in plants

    SciTech Connect

    Huang, J.W.; Blaylock, M.J.; Kapulnik, Y.; Ensley, B.D.

    1998-07-01

    Uranium phytoextraction, the use of plants to extract U from contaminated soils, is an emerging technology. The authors report on the development of this technology for the cleanup of U-contaminated soils. In this research, they investigated the effects of various soil amendments on U desorption from soil to soil solution, studied the physiological characteristics of U uptake and accumulation in plants, and developed techniques to trigger U hyperaccumulation in plants. A key to the success of U phytoextraction is to increase soil U availability to plants. The authors have found that some organic acids can be added to soils to increase U desorption from soil to soil solution and to trigger a rapid U accumulation in plants. Of the organic acids (acetic acid, citric acid, and malic acid) tested, citric acid was the most effective in enhancing U accumulation in plants. Shoot U concentrations of Brassica juncea and Brassica chinensis grown in a U-contaminated soil increased from less than 5 mg kg{sup {minus}1} to more than 5,000 mg kg{sup {minus}1} in citric acid-treated soils. To their knowledge, this is the highest shoot U concentration reported for plants grown on U-contaminated soils. Using this U hyperaccumulation technique, they are now able to increase U accumulation in shoots of selected plant species grown in two U-contaminated soils by more than 1,000-fold within a few days. The results suggest that U phytoextraction may provide an environmentally friendly alternative for the cleanup of U-contaminated soils.

  7. [Effects of Low-Molecular-Weight Organic Acids on the Speciation of Pb in Purple Soil and Soil Solution].

    PubMed

    Liu, Jiang; Jiang, Tao; Huang, Rong; Zhang, Jin-zhong; Chen, Hong

    2016-04-15

    Lead (Pb) in purple soil was selected as the research target, using one-step extraction method with 0.01 mol · L⁻¹ sodium nitrate as the background electrolyte to study the release effect of citric acid (CA), tartaric acid (TA) and acetic acid (AC) with different concentrations. Sequential extraction and geochemical model (Visual Minteq v3.0) were applied to analyze and predict the speciation of Pb in soil solid phase and soil solution phase. Then the ebvironmental implications and risks of low-molecule weight organic acid (LMWOA) on soil Pb were analyzed. The results indicated that all three types of LMWOA increased the desorption capacity of Pb in purple soil, and the effect followed the descending order of CA > TA > AC. After the action of LMWOAs, the exchangeable Pb increased; the carbonate-bound Pb and Fe-Mn oxide bound Pb dropped in soil solid phase. Organic bound Pb was the main speciation in soil solution phase, accounting for 45.16%-75.05%. The following speciation of Pb in soil solution was free Pb, accounting for 22.71%-50.25%. For CA and TA treatments, free Pb ions and inorganic bound Pb in soil solution increased with increasing LMWOAs concentration, while organic bound Pb suffered a decrease in this process. An opposite trend for AC treatment was observed compared with CA and TA treatments. Overall, LMWOAs boosted the bioavailability of Pb in purple soil and had a potential risk to contaminate underground water. Among the three LMWOAs in this study, CA had the largest potential to activate soil Pb.

  8. Biological Activities of Uric Acid in Infection Due to Enteropathogenic and Shiga-Toxigenic Escherichia coli

    PubMed Central

    Broome, Jacqueline E.; Lis, Agnieszka

    2016-01-01

    In previous work, we identified xanthine oxidase (XO) as an important enzyme in the interaction between the host and enteropathogenic Escherichia coli (EPEC) and Shiga-toxigenic E. coli (STEC). Many of the biological effects of XO were due to the hydrogen peroxide produced by the enzyme. We wondered, however, if uric acid generated by XO also had biological effects in the gastrointestinal tract. Uric acid triggered inflammatory responses in the gut, including increased submucosal edema and release of extracellular DNA from host cells. While uric acid alone was unable to trigger a chloride secretory response in intestinal monolayers, it did potentiate the secretory response to cyclic AMP agonists. Uric acid crystals were formed in vivo in the lumen of the gut in response to EPEC and STEC infections. While trying to visualize uric acid crystals formed during EPEC and STEC infections, we noticed that uric acid crystals became enmeshed in the neutrophilic extracellular traps (NETs) produced from host cells in response to bacteria in cultured cell systems and in the intestine in vivo. Uric acid levels in the gut lumen increased in response to exogenous DNA, and these increases were enhanced by the actions of DNase I. Interestingly, addition of DNase I reduced the numbers of EPEC bacteria recovered after a 20-h infection and protected against EPEC-induced histologic damage. PMID:26787720

  9. Effect of soil acidity factors on yields and foliar composition of tropical root crops

    SciTech Connect

    Abruna-Rodriguez, F.; Vicente-Chandler, J.I. Rivera, E.; Rodriguez, J.

    1982-09-01

    Tropical root crops, a major source of food for subsistence farmers, varied in their sensitivity to soil acidity factors. Tolerance to soil acidity is an important characteristic of crops for the humid tropics where soils are often very acid and lime-scarce and expensive. Experiments on two Ultisols and an Oxisol showed that three tropical root crops differed markedly in sensitivity to soil acicity factors. Yams (Dioscorea alata L.) were very sensitive to soil acidity with yields on a Ultisol decreasing from 70% of maximum when Al saturation of the effective cation exchange capacity of the soil was 10 to 25% of maximum when Al saturation was 40%. On the other hand, cassava (Manihot esculenta Crantz) was very tolerant to high levels of soil acidity, yielding about 85% of maximum with 60% Al saturation. Taniers (Xanthosoma sp.) were intermediate between yams and cassava in their tolerance to soil acidity yielding about 60% of maximum with 50% Al saturation of the soil. Foliar composition of cassava was not affected by soil acidity levels and that of yams and taniers was also unaffected except for Ca content which decreased with decreasing soil pH and increasing Al saturation.Response of these tropical root crops to soil acidity components was far more striking on Ultisols than on the Oxisol. For yams, soils should be limed to about pH 5.5 with essentially no exhangeable Al/sup 3 +/ present whereas high yields of taniers can be obtained at about pH 4.8 with 20% exchangeable Al/sup 3 +/ and of cassava at pH as low as 4.5 with 60% exchangeable Al/sup 3 +/.

  10. Abscisic acid in soil facilitates community succession in three forests in China.

    PubMed

    Zhao, Houben; Peng, Shaolin; Chen, Zhuoquan; Wu, Zhongmin; Zhou, Guangyi; Wang, Xu; Qiu, Zhijun

    2011-07-01

    Plants release secondary metabolites into the soil that change the chemical environment around them. Exogenous abscisic acid (ABA) is an important allelochemical whose role in successional trajectories has not been examined. We hypothesized that ABA can accumulate in the soil through successional processes and have an influence on forest dynamics. To this end, we investigated the distribution of ABA in forest communities from early to late successional stages and the response of dominant species to the gradient of ABA concentrations in three types of forests from northern to southern China. Concentrations of ABA in the soils of three forest types increased from early to late successional stages. Pioneer species' litters had the lowest ABA content, and their seed germination and seedling early growth were the most sensitive to the inhibitory effect of ABA. Mid- and late-successional species had a much higher ABA content in fallen leaves than pioneer species, and their seed germination and seedling early growth were inhibited by higher concentrations of ABA than pioneers. Late-successional species showed little response to the highest ABA concentration, possibly due to their large seed size. The results suggest that ABA accumulates in the soil as community succession proceeds. Sensitivity to ABA in the early stages, associated with other characteristics, may result in pioneer species losing their advantage in competition with late-successional species in an increasingly high ABA concentration environment, and being replaced by ABA-tolerant, late-successional species.

  11. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils.

    PubMed

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2) were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH) were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH.

  12. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils

    PubMed Central

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2) were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH) were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH. PMID:26397367

  13. Uncertainties due to soil data in Flood Risk Forecasts with the Water Balance Model LARSIM

    NASA Astrophysics Data System (ADS)

    Mitterer, Johannes

    2016-04-01

    Reliable flood forecasts with quantitative statements about contained uncertainties are essential for far reaching decisions in disaster management. In this paper uncertainties resulting from soil data are analysed for the in the German-speaking world widely used water balance model LARSIM and quantified as far as possible. At the beginning a structural and statistical analysis about the wittingly simple designed soil module is performed. It consists of a storage volume with four separate runoff components only defined by the storage size. Additionally, the model structure is examined with regard to effects of uncertain soil data using a soil map from the Bavarian State Institute for Forestry which already contains estimated minimum and maximum values for important soil parameters. For further analysis, two German catchments in Upper Franconia located at the White Main with a size of 250 km² each, covering a huge variety of soil types are used as case examples. Skeleton is identified as an important source of uncertainty in soil data comparing the quantifiable information of available soil maps and using field and laboratory analysis. Furthermore, surface runoff and fast interflow fluxes show up to be sensitive for peaks of flood events, whereas slow interflow and base flow fluxes have smaller and more long term effects on discharges and the water balance. A reduction of the soil storage basically leads to a more intensified reaction of discharges than an enlargement. The calculation of two extreme scenarios within the statistical analysis result in simulated gage measurements varying from -42 % till +218 % compared to the scenario with the main value of the map. A percental variation of the soil storage shows a doubling of the flood discharges, if the storage size is halved and a reduction up to 20% using a doubled one. Finally, a Monte Carlo Simulation is performed using the statistical data of the soil map combined with a normal distribution, whereby the

  14. The microbial communities and potential greenhouse gas production in boreal acid sulphate, non-acid sulphate, and reedy sulphidic soils.

    PubMed

    Šimek, Miloslav; Virtanen, Seija; Simojoki, Asko; Chroňáková, Alica; Elhottová, Dana; Krištůfek, Václav; Yli-Halla, Markku

    2014-01-01

    Acid sulphate (AS) soils along the Baltic coasts contain significant amounts of organic carbon and nitrogen in their subsoils. The abundance, composition, and activity of microbial communities throughout the AS soil profile were analysed. The data from a drained AS soil were compared with those from a drained non-AS soil and a pristine wetland soil from the same region. Moreover, the potential production of methane, carbon dioxide, and nitrous oxide from the soils was determined under laboratory conditions. Direct microscopic counting, glucose-induced respiration (GIR), whole cell hybridisation, and extended phospholipid fatty acid (PLFA) analysis confirmed the presence of abundant microbial communities in the topsoil and also in the deepest Cg2 horizon of the AS soil. The patterns of microbial counts, biomass and activity in the profile of the AS soil and partly also in the non-AS soil therefore differed from the general tendency of gradual decreases in soil profiles. High respiration in the deepest Cg2 horizon of the AS soil (5.66 μg Cg(-1)h(-1), as compared to 2.71 μg Cg(-1)h(-1) in a top Ap horizon) is unusual but reasonable given the large amount of organic carbon in this horizon. Nitrous oxide production peaked in the BCgc horizon of the AS and in the BC horizon of the non-AS soil, but the peak value was ten-fold higher in the AS soil than in the non-AS soil (82.3 vs. 8.6 ng Ng(-1)d(-1)). The data suggest that boreal AS soils on the Baltic coast contain high microbial abundance and activity. This, together with the abundant carbon and total and mineral nitrogen in the deep layers of AS soils, may result in substantial gas production. Consequently, high GHG emissions could occur, for example, when the generally high water table is lowered because of arable farming.

  15. An assessment of soil contamination due to heavy metals around a coal-fired thermal power plant in India

    NASA Astrophysics Data System (ADS)

    Mandal, A.; Sengupta, D.

    2006-11-01

    Combustion of coals in thermal power plants is one of the major sources of environmental pollution due to generation of huge amounts of ashes, which are disposed off in large ponds in the vicinity of the thermal power plants. This problem is of particular significance in India, which utilizes coals of very high ash content (˜55 wt%). Since the thermal power plants and the ash ponds are located in densely populated areas, there is potential chance for contamination of soil and groundwater of the surrounding areas from the toxic trace elements in the ash. An attempt has been made to study the extent of soil contamination around one of the largest thermal power plants of India located at Kolaghat, West Bengal India. Chemical analysis of the top soils and the soils collected from the different depth profiles surrounding the ash ponds, show that the top soils are enriched in the trace elements Mo, As, Cr, Mn, Cu, Ni, Co, Pb, Be, V, Zn, which show maximum enrichment (2-5) in the top soils collected from all the soil profiles. These elements are also enriched in the pond ash. Since there are no other sources of industrial effluents, it can be said that the enrichment of the trace elements (Mn, Co, Mo, Cr, Cu, Pb, Zn, As, Ni, Be, V) is attributed to their input from ash from the disposal pond. The study has been further strengthened by log-normal distribution pattern of the elements.

  16. Soil-calcium depletion linked to acid rain and forest growth in the eastern United States

    USGS Publications Warehouse

    Lawrence, Gregory B.; Huntington, T.G.

    1999-01-01

    Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

  17. Measurement of δ13C values of soil amino acids by GC-C-IRMS using trimethylsilylation: a critical assessment.

    PubMed

    Rubino, Mauro; Milin, Sylvie; D'Onofrio, Antonio; Signoret, Patrick; Hatté, Christine; Balesdent, Jérôme

    2014-01-01

    In this study, we evaluated trimethylsilyl (TMS) derivatives as derivatization reagents for the compound-specific stable carbon isotope analysis of soil amino acids by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). We used non-proteinogenic amino acids to show that the extraction-derivatization-analysis procedure provides a reliable method to measure δ(13)C values of amino acids extracted from soil. However, we found a number of drawbacks that significantly increase the final total uncertainty. These include the following: production of multiple peaks for each amino acid, identified as di-, tri- and tetra-TMS derivatives; a number of TMS-carbon (TMS-C) atoms added lower than the stoichiometric one, possibly due to incomplete combustion; different TMS-C δ(13)C for di-, tri- and tetra-TMS derivatives. For soil samples, only four amino acids (leucine, valine, threonine and serine) provide reliable δ(13)C values with a total average uncertainty of 1.3 ‰. We conclude that trimethylsilyl derivatives are only suitable for determining the (13)C incorporation in amino acids within experiments using (13)C-labelled tracers but cannot be applied for amino acids with natural carbon isotope abundance until the drawbacks described here are overcome and the measured total uncertainty significantly decreased.

  18. Organic amendment effects on the transformation and fractionation of aluminum in acidic sandy soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was attempted to evaluate the transformation of aluminum (Al) in an acidic sandy soil amended with composts (yard waste, yard + municipal waste, GreenEdge®, and synthetic humic acid), based on soil Al fractionation by single and sequential extraction. The compost amendment significantly i...

  19. Humic acid toxicity in biologically treated soil contaminated with polycyclic aromatic hydrocarbons and pentachlorophenol.

    PubMed

    Nieman, J K C; Sims, R C; Sorensen, D L; McLean, J E

    2005-10-01

    Contaminated soil from a land treatment unit at the Libby Groundwater Superfund Site in Libby, MT, was amended with 14C pyrene and incubated for 396 days to promote biodegradation and the formation of soil-associated bound residues. Humic and fulvic acids were extracted from the treated soil microcosms and analyzed for the presence of pyrene residues. Biologic activity promoted 14C association with the fulvic acid fraction, but humic acid-associated 14C did not increase with biologic activity. The Aboatox flash toxicity assay was used to assess the toxicity of humic and fulvic acid fractions. The fulvic acid gave no toxic response, but the humic acid showed significant toxicity. The observed toxicity was likely associated with pentachlorophenol, a known contaminant of the soil that was removed by solvent extraction of the humic acid and that correlated well with toxicity reduction.

  20. Valuation of damages to recreational trout fishing in the Upper Northeast due to acidic deposition

    SciTech Connect

    Englin, J.E.; Cameron, T.A.; Mendelsohn, R.E.; Parsons, G.A.; Shankle, S.A.

    1991-04-01

    This report documents methods used to estimate economic models of changes in recreational fishing due to the acidic deposition. The analysis was conducted by Pacific Northwest Laboratory (PNL) and its subcontractors for the US Environmental Protection Agency (EPA) and the US Department of Energy (DOE) in support of the National Acidic Precipitation Assessment Program (NAPAP). The primary data needed to estimate these models were collected in the 1989 Aquatic Based Recreation Survey (ABRS), which was jointly funded by the DOE and the EPA's Office of Policy Planning and Evaluation. 11 refs., 5 figs., 15 tabs.

  1. External auditory canal stenosis due to the use of powdered boric acid.

    PubMed

    Dündar, Riza; Soy, Fatih Kemal; Kulduk, Erkan; Muluk, Nuray Bayar; Cingi, Cemal

    2014-09-01

    Acquired stenosis of the external auditory canal (EAC) may occur because of chronic external otitis, recurrent chronic catarrhal otitis media associated with tympanic membrane perforation, chronic dermatitis, tumors, and trauma. Stenosis occurs generally at the one-third bone part of the external auditory canal. In this article, we present 3 cases of acquired EAC stenosis due to the previous powdered boric acid application. Besides the presentation of surgical intervetions in these cases, we want to notify the physicians not to use or carefully use powdered boric acid because of the complication of EAC stenosis.

  2. Soil acidity reconstruction based on tree ring information of a dominant species Abies fabri in the subalpine forest ecosystems in southwest China.

    PubMed

    Chen, Lei; Wu, Fei-Hua; Liu, Ting-Wu; Chen, Juan; Li, Zhen-Ji; Pei, Zhen-Ming; Zheng, Hai-Lei

    2010-10-01

    To assess the suitability of dendrochemistry as an indicator of soil acidification, soil chemistry and tree ring information of Abies fabri were measured at two distinct sites (severe acid deposition site-Emei Mountain and clean site-Gongga Mountain) of the subalpine forest ecosystems of western Sichuan, southwest China. The actual soil acidity (pH) was significantly correlated with some of the recent xylem cation (Ca, Mg, Mn, Al, Sr and Ba) concentrations and their molar ratios. Xylem Ca/Mg and Ca/Mn of A. fabri were ultimately selected to reconstruct the historical changes of soil pH in Emei Mountain and Gongga Mountain, respectively. The validity of those rebuild was also verified to a certain extent. We conclude that xylem cation molar ratios of A. fabri were superior to the single cation concentrations in soil acidity rebuild at the study sites due to normalizing for concentration fluctuations.

  3. A case report of a chemical burn due to the misuse of glacial acetic acid.

    PubMed

    Yoo, Jun-Ho; Roh, Si-Gyun; Lee, Nae-Ho; Yang, Kyung-Moo; Moon, Ji-Hyun

    2010-12-01

    As young and elastic skin is what everyone dreams of, various measures have been implemented including chemical, laser resurfacing and dermabrasion to improve the condition of ageing skin. However, the high cost of these procedures prevents the poor from having access to treatment. Glacial acetic acid is widely used as a substitute for chemical peeling because it is readily easily available and affordable. However, its use can result in a number of serious complications. A 28-year-old female patient was admitted to our hospital with deep second-degree chemical burns on her face caused by the application of a mixture of glacial acetic acid and flour for chemical peeling. During a 6-month follow-up, hypertrophic scarring developed on the both nasolabial folds despite scar management. Glacial acetic acid is a concentrated form of the organic acid, which gives vinegar its sour taste and pungent smell, and it is also an important reagent during the production of organic compounds. Unfortunately, misleading information regarding the use of glacial acetic acid for chemical peeling is causing serious chemical burns. Furthermore, there is high possibility of a poor prognosis, which includes inflammation, hypertrophic scar formation and pigmentation associated with its misuse. Therefore, we report a case of facial chemical burning, due to the misuse of glacial acetic acid, and hope that this report leads to a better understanding regarding the use of this reagent.

  4. Soil moisture decline due to afforestation across the Loess Plateau, China

    NASA Astrophysics Data System (ADS)

    Jia, Xiaoxu; Shao, Ming'an; Zhu, Yuanjun; Luo, Yi

    2017-03-01

    The Loess Plateau of China is a region with one of the most severe cases of soil erosion in the world. Since the 1950s, there has been afforestation measure to control soil erosion and improve ecosystem services on the plateau. However, the introduction of exotic tree species (e.g., R. pseudoacacia, P. tabulaeformis and C. korshinskii) and high-density planting has had a negative effect on soil moisture content (SMC) in the region. Any decrease in SMC could worsen soil water shortage in both the top and deep soil layers, further endangering the sustainability of the fragile ecosystem. This study analyzed the variations in SMC following the conversion of croplands into forests in the Loess Plateau. SMC data within the 5-m soil profile were collected at 50 sites in the plateau region via field survey, long-term in-situ observations and documented literature. The study showed that for the 50 sites, the depth-averaged SMC was much lower under forest than under cropland. Based on in-situ measurements of SMC in agricultural plots and C. korshinskii plots in 2004-2014, SMC in the 0-4 m soil profile in both plots declined significantly (p < 0.01) during the growing season. The rate of decline in SMC in various soil layers under C. korshinskii plots (-0.008 to -0.016 cm3 cm-3 yr-1) was much higher than those under agricultural plots (-0.004 to -0.005 cm3 cm-3 yr-1). This suggested that planting C. korshinskii intensified soil moisture decline in China's Loess Plateau. In the first 20-25 yr of growth, the depth-averaged SMC gradually decreased with stand age in R. pseudoacacia plantation, but SMC somehow recovered with increasing tree age over the 25-year period. Irrespectively, artificial forests consumed more deep soil moisture than cultivated crops in the study area, inducing soil desiccation and dry soil layer formation. Thus future afforestation should consider those species that use less water and require less thinning for sustainable soil conservation without

  5. Iron isotopes in a soil chronosequence: evidence of fractionation due to biological lifting of iron

    NASA Astrophysics Data System (ADS)

    Schulz, M. S.; Bullen, T. D.; White, A. F.; Fitzpatrick, J.

    2009-12-01

    The evolution of iron distribution with landform exposure time was studied in a marine terrace chronosequence northwest of Santa Cruz, California. The abundance of soil Fe increases with terrace age on the five terraces studied (65 to 226 Ka). Mass change calculations for Fe, indicate that not only is iron concentrated near the surface but, it is also depleted at depths >1.5m. The surficial Fe concentration cannot be fully accounted for by weathering and compaction of the soil profile or by the addition of iron content through eolian deposition to the soils. The terrace regoliths were generally unsaturated and aerobic, thus lateral movement of large amounts of dissolved reduced iron is unlikely. We propose that plant roots and symbiotic fungi (mycorrhizae) have transported iron from deep within the regolith to the shallow soil through the process of biolifting. Iron is a plant micronutrient; and unlike other mineral nutrients, it is relatively insoluble in aerobic soil solutions. Once Fe is released from decaying organic matter, the Fe-oxides are incorporated into the shallow soil. The Fe content of the current grassland vegetation was measured and yearly biomass Fe uptake calculated. The yearly cycling of plant-utilized Fe in above ground biomass multiplied by the age of the terrace is roughly equivalent to the shallow iron content of these soils. It has been shown that plants which use the strategy I Fe uptake process fractionate light Fe (Guelke and Von Blankenburg, ES&T, p1896; 2007). To test the biolifting hypothesis, Fe isotope ratios were determined for bulk soil samples from several soil depths of terraces 1 through 3 and terrace 5. The shallow soils generally have increasingly lighter δ56/54Fe with terrace age. The δ 56/54Fe values at 10cm soil depth are: 0.546, 0.628 0.381 and 0.182. The deep soil samples (>3 m) have a relatively constant isotopic composition ranging from 0.595 to 0.678 δ 56/54Fe. The deep sample ratios are between the values of the

  6. [Enhanced phytoextraction of heavy metal contaminated soil by chelating agents and auxin indole-3-acetic acid].

    PubMed

    Zhou, Jian-min; Dang, Zhi; Chen, Neng-chang; Xu, Sheng-guang; Xie, Zhi-yi

    2007-09-01

    The environmental risk of chelating agents such as EDTA application to the heavy metals polluted soils and the stress on plant roots due to the abrupt increase metals concentration limit the wide commercial use of chelate-induced phytoextraction. Chelating agent ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) and auxin indole-3-acetic acid (IAA) were used for enhancing heavy metals uptake from soils by Zea mays L. (corn) in pot experiments. The metals content in plant tissues was quantified using an inductively coupled plasma mass spectrometer (ICP-MS). The results showed that the combination of IAA and EDTA increased the biomass by about 40.0% and the contents of Cu, Zn, Cd and Pb in corn shoots by 27.0%, 26.8%, 27.5% and 32.8% respectively, as compared to those in EDTA treatment. While NTA&IAA treatment increased the biomass by about 29.9% and the contents of Cu, Zn, Cd and Pb in corn shoots by 31.8%, 27.6%, 17.0% and 26.9% respectively, as compared to those in NTA treatment. These results indicated that corn growth was promoted, and the biomass and the accumulation of heavy metals in plant shoots were increased significantly with the addition of IAA, which probably helps to change the cell membrane properties and the biomass distribution, resulting in the alleviation of the phytotoxicity of metals and the chelating agents.

  7. Groundwater or floodwater? Assessing the pathways of metal exports from a coastal acid sulfate soil catchment.

    PubMed

    Santos, Isaac R; de Weys, Jason; Eyre, Bradley D

    2011-11-15

    Daily observations of dissolved aluminum, iron, and manganese in an estuary downstream of a coastal acid sulfate soil (CASS) catchment provided insights into how floods and submarine groundwater discharge drive wetland metal exports. Extremely high Al, Fe, and Mn concentrations (up to 40, 374, and 8 mg L(-1), respectively) were found in shallow acidic groundwaters from the Tuckean Swamp, Australia. Significant correlations between radon (a natural groundwater tracer) and metals in surface waters revealed that metal loads were driven primarily by groundwater discharge. Dissolved Fe, Mn, and Al loads during a 16-day flood triggered by a 213 mm rain event were respectively 80, 35, and 14% of the total surface water exports during the four months of observations. Counter clockwise hysteresis was observed for Fe and Mn in surface waters during the flood due to delayed groundwater inputs. Groundwater-derived Fe fluxes into artificial drains were 1 order of magnitude higher than total surface water exports, which is consistent with the known accumulation of monosulfidic black ooze within the wetland drains. Upscaling the Tuckean catchment export estimates yielded dissolved Fe fluxes from global acid sulfate soil catchments on the same order of magnitude of global river inputs into estuaries.

  8. Coal mining activities change plant community structure due to air pollution and soil degradation.

    PubMed

    Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

    2014-10-01

    The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

  9. Evidence that the reactivity of the martian soil is due to superoxide ions.

    PubMed

    Yen, A S; Kim, S S; Hecht, M H; Frant, M S; Murray, B

    2000-09-15

    The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.

  10. Changes in soil properties due to irrigation with paper industry wastewater.

    PubMed

    Roy, Ratna P; Prasad, Jagdish; Joshi, A P

    2008-10-01

    The effect of irrigation by the effluent of paper industry versus well water on properties of soils in three seasons was studied in Nagpur district, Maharashtra. The effluent had high total dissolved salts and biological oxygen demand than well water. pH, EC and availability of N, P, K, Zn, Cu, Fe, Mn, Cd, Co, Cr, Ni, Pb, particularly in surface layer of paper industry effluent irrigated soil at different seasons found to increase compared to well water irrigated soils, but heavy metals (non-essential nutrients) were within the permissible limits.

  11. Evidence that the reactivity of the martian soil is due to superoxide ions

    NASA Technical Reports Server (NTRS)

    Yen, A. S.; Kim, S. S.; Hecht, M. H.; Frant, M. S.; Murray, B.

    2000-01-01

    The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.

  12. Soil organic carbon stocks and fluxes due to land use conversions at the European scale

    NASA Astrophysics Data System (ADS)

    Gobin, A.; Campling, P.

    2012-04-01

    European soils store around 73 to 79 billion tonnes of carbon, which is about 50 times the total CO2-equivalent emissions of the 27 Member States of the European Union in 2009 (4.6 billion tones; EEA, 2010). More than twice as much carbon is held in soils as compared to the storage in vegetation or the atmosphere. Soil organic carbon (SOC) stocks are dynamic and changes in land use, land management and climate may result in instant losses, whereas gains accumulate more slowly over several decades. The soil organic carbon cycle is based on continually supplying carbon in the form of organic matter as a food source for microorganisms, the loss of some carbon as carbon dioxide, and the assimilation of stable carbon in the soil. The organic carbon stocks and fluxes to and from the soil across the EU were quantified for agriculture, forestry and peatlands under different land use change and management scenarios taking into account climate change and using a coupled regional balance and multi-compartment soil organic matter model (Roth-C). Abolishing permanent grassland restrictions would have a negative effect on SOC stocks, which at the EU level can be quantified in a loss 30% higher than in the case of maintaining the current permanent grassland restrictions. Promoting the afforestation of 10% and 25% former set-aside land in the EU-15 would reduce the loss of SOC stock by 2030 by 19% and 65% respectively compared to conversions to arable land. An increase of the current afforestation rates by 2% would result in a 10% increase in carbon stock levels by 2030. The combined effect of the land use conversions to and from agricultural land use demonstrate an EU-27 average -9.7 tonnes/ha SOC stock loss for the worst option and a +5.0 tonnes/ha SOC stock gain for C-Rich option. Larger variations between Member States than between scenario options stem from regional differences in bio-geography, soil types and climatic regimes. The amount of stable or humified organic carbon

  13. Crossing the pedogenetic threshold: Apparent phosphorus limitation by soil microorganisms in unglaciated acidic eastern hardwood forests

    NASA Astrophysics Data System (ADS)

    Deforest, J. L.; Smemo, K. A.; Burke, D. J.

    2010-12-01

    The availability of soil phosphorus (P) can significantly influence microbial community composition and the ecosystem-level processes they mediate. However, the threshold at which soil microorganisms become functionally P-limited is unclear because of soil acidity effect on P availability. We reason that acidic temperate hardwood forest ecosystems are, in fact, functionally P-limited, but compensation occur via soil microbial production of phosphatase enzymes. We tested this hypothesis in glaciated and unglaciated mature mixed-mesophytic forests in eastern Ohio where both soil pH and P availability had been experientially manipulated. We measured the activity of two P acquiring soil enzymes, phosphomonoesterase (PMono) and phosphodiesterase (PDi), to understand how soil acidity and available P influence microbial function. Our experimental treatments elevated ambient soil pH from below 4.5 to around 5.5 and increased readily available phosphate from 3 to ~25 mg P/kg on glaciated soils and from 0.5 to ~5 mg P/kg on unglaciated soils. The P treatment decreased the activity of PDi by 82% relative to the control on unglaciated soils, but we observed no P treatment effect on glaciated soils. A similar result was observed for PMono. Soil pH, alone, did not significantly influence enzyme activities. Results suggest that soil microorganisms are more likely to be P-limited in older unglaciated soils. However, dramatically higher phosphatase activity in response to very low P availability suggests that an underlying ecosystem P limitation can be ameliorated by soil microbial community dynamics. This mechanism may be more important for older, unglaciated soils that have already crossed a pedogenic threshold where P availability influences ecosystem and microbial function.

  14. Detecting crop yield reduction due to irrigation-induced soil salinization in South-West Russia

    NASA Astrophysics Data System (ADS)

    Argaman, E.; Beets, W.; Croes, J.; Keesstra, S.; Verzandvoort, S.; Zeiliguer, A.

    2012-04-01

    The South-European part of the Russian Federation has experienced serious land degradation in the form of soil salinization since the 1960s. This land degradation was caused by intensive, large-scale irrigation on reclaimed land in combination with the salt-rich nature of the substrate. Alkaline soil salinity is believed to be an important factor decreasing crop yield in this area. A large research effort has been directed to the effects of soil salinity on crops, there is a need for simple, easily determinable indicators of crop health and soil salinity in irrigated systems, that can help to detect crop water stress in an early stage. The objectives of this research were to study the effects of soil salinity and vegetation water stress on the performance of alfalfa crop yield and physiological crop properties, and to study the possibility to measure soil salinity and alkalinity and the crop water stress index at plot level using a thermal gun and a regular digital camera. The study area was located in Saratov District, in the South-West part of Russia. Variables on the surface energy balance, crop properties, soil properties and visible reflectance were measured on plots with alfalfa cultures in two fields with and without signs of alkaline soil salinity, and with and without irrigation in July 2009. The research showed no clear adverse effects of soil salinity and soil alkalinity on crop yield and physiological crop properties. Soil salinity, as reflected by the electric conductivity, positively affected the root biomass of alfalfa in the range of 0.15 to 1.52 dS/m . This was a result of EC levels being below the documented threshold to negatively affect Alfalfa, as would be the case in truly saline soils. The soil pH also showed a positive correlation with root biomass within the range of pH 6.2 and 8.5 . From the literature these pH values are generally believed to be too high to exhibit a positive relationship with root biomass. No relationship was found

  15. Salt and N leaching and soil accumulation due to cover cropping practices

    NASA Astrophysics Data System (ADS)

    Gabriel, J. L.; Quemada, M.

    2012-04-01

    Nitrate leaching beyond the root zone can increase water contamination hazards and decrease crop available N. Cover crops used in spite of fallow are an alternative to reduce nitrate contamination in the vadose zone, because reducing drainage and soil mineral N accumulation. Cover crops can improve important characteristics in irrigated land as water retention capacity or soil aggregate stability. However, increasing evapotranspiration and consequent drainage below the root system reduction, could lead to soil salt accumulation. Salinity affects more than 80 million ha of arable land in many areas of the world, and one of the principal causes for yield reduction and even land degradation in the Mediterranean region. Few studies dealt with both problems at the same time. Therefore, it is necessary a long-term evaluation of the potential effect on soil salinity and nitrate leaching, in order to ensure that potential disadvantages that could originate from soil salt accumulation are compensated with all advantages of cover cropping. A study of the soil salinity and nitrate leaching was conducted during 4 years in a semiarid irrigated agricultural area of Central Spain. Three treatments were studied during the intercropping period of maize (Zea mays L.): barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Cover crops were killed in March allowing seeding of maize of the entire trial in April, and all treatments were irrigated and fertilised following the same procedure. Before sowing, and after harvesting maize and cover crops, soil salt and nitrate accumulation was determined along the soil profile. Soil analysis was conducted at six depths every 0.20 m in each plot in samples from four 0 to 1.2-m depth holes dug. The electrical conductivity of the saturated paste extract and soil mineral nitrogen was measured in each soil sample. A numerical model based on the Richards water balance equation was applied in order to calculate drainage at 1.2 m depth

  16. Non-steady State Soil Organic Carbon Storage in Undisturbed Watersheds Due to Diffusive Sediment Transport

    NASA Astrophysics Data System (ADS)

    Yoo, K.; Amundson, R.; Heimsath, A. M.; Dietrich, W. E.

    2003-12-01

    Most soil C models assume that plant C inputs are matched by C loss through heterotrophic respiration. While these models are applicable for level terrain, on soil mantled uplands in hilly to mountainous regions, persistent soil mass transport represents a potentially large, but unstudied, flux of soil C. In this research we quantify the soil C erosional fluxes and non-steady state soil C storage within two undisturbed grass-covered hillslopes in Coastal California: Tennessee Valley (TV) (coastal Marin County) and Black Diamond (BD) (interior Contra Costa County). At both sites, previous geomorphic studies have quantified both the sediment transport processes (TV= gopher driven sediment transport; BD= abiotic soil shrink/swell) and their rates. Hillslope patterns of soil C storage were examined in relation to slope position with a hillslope sediment transport model. The average C erosion rates from convex slopes are between 1.4 and 2.7 g C m -2 yr-1 at TV and approximately 8 g C m-2 yr-1 at BD. The C erosional flux is locally as high as 14% of above ground net primary productivity (NPP) at TV and 8% at BD. The convex slopes are net C sinks because NPP likely exceeds respiration by a value equaling the size of C erosion. Eroded soils ultimately accumulate in depositional settings which have residence times on the order of 13kyrs at TV and 5.3kyrs at BD. At TV hollow, 15-24 kg C m-2 of soil C has accumulated at a long-term rate of 1.6-1.9 g C m-2 yr-1 . The present rates of C accumulation were calculated to be 0.3 g C m-2 yr-1 at TV and 0.6 g C m-2 yr-1 at BD. During the hollow infilling, the depositional C inputs have been greater than C accumulation rates, meaning that much of the incoming eroded C is ultimately oxidized to CO2. At both sites, a fraction of the eroded C is exported from the watershed (C of 0.1-0.5 g C m-2 yr-1 at TV and 2 g C m-2 yr-1 at BD). When all hillslope components are integrated, these watersheds are continuous atmospheric C sinks at rates

  17. Sustainable Soil Washing: Shredded Card Filtration of Potentially Toxic Elements after Leaching from Soil Using Organic Acid Solutions.

    PubMed

    Ash, Christopher; Drábek, Ondřej; Tejnecký, Václav; Jehlička, Jan; Michon, Ninon; Borůvka, Luboš

    2016-01-01

    Shredded card (SC) was assessed for use as a sorbent of potentially toxic elements (PTE) carried from contaminated soil in various leachates (oxalic acid, formic acid, CaCl2, water). We further assessed SC for retention of PTE, using acidified water (pH 3.4). Vertical columns and a peristaltic pump were used to leach PTE from soils (O and A/B horizons) before passing through SC. Sorption onto SC was studied by comparing leachates, and by monitoring total PTE contents on SC before and after leaching. SC buffers against acidic soil conditions that promote metals solubility; considerable increases in solution pH (+4.49) were observed. Greatest differences in solution PTE content after leaching with/without SC occurred for Pb. In oxalic acid, As, Cd, Pb showed a high level of sorption (25, 15, and 58x more of the respective PTE in leachates without SC). In formic acid, Pb sorption was highly efficient (219x more Pb in leachate without SC). In water, only Pb showed high sorption (191x more Pb in leachate without SC). In desorption experiments, release of PTE from SC varied according to the source of PTE (organic/mineral soil), and type of solvent used. Arsenic was the PTE most readily leached in desorption experiments. Low As sorption from water was followed by fast release (70% As released from SC). A high rate of Cd sorption from organic acid solutions was followed by strong retention (~12% Cd desorption). SC also retained Pb after sorption from water, with subsequent losses of ≤8.5% of total bound Pb. The proposed use of this material is for the filtration of PTE from extract solution following soil washing. Low-molecular-mass organic acids offer a less destructive, biodegradable alternative to strong inorganic acids for soil washing.

  18. Sustainable Soil Washing: Shredded Card Filtration of Potentially Toxic Elements after Leaching from Soil Using Organic Acid Solutions

    PubMed Central

    Ash, Christopher; Drábek, Ondřej; Tejnecký, Václav; Jehlička, Jan; Michon, Ninon; Borůvka, Luboš

    2016-01-01

    Shredded card (SC) was assessed for use as a sorbent of potentially toxic elements (PTE) carried from contaminated soil in various leachates (oxalic acid, formic acid, CaCl2, water). We further assessed SC for retention of PTE, using acidified water (pH 3.4). Vertical columns and a peristaltic pump were used to leach PTE from soils (O and A/B horizons) before passing through SC. Sorption onto SC was studied by comparing leachates, and by monitoring total PTE contents on SC before and after leaching. SC buffers against acidic soil conditions that promote metals solubility; considerable increases in solution pH (+4.49) were observed. Greatest differences in solution PTE content after leaching with/without SC occurred for Pb. In oxalic acid, As, Cd, Pb showed a high level of sorption (25, 15, and 58x more of the respective PTE in leachates without SC). In formic acid, Pb sorption was highly efficient (219x more Pb in leachate without SC). In water, only Pb showed high sorption (191x more Pb in leachate without SC). In desorption experiments, release of PTE from SC varied according to the source of PTE (organic/mineral soil), and type of solvent used. Arsenic was the PTE most readily leached in desorption experiments. Low As sorption from water was followed by fast release (70% As released from SC). A high rate of Cd sorption from organic acid solutions was followed by strong retention (~12% Cd desorption). SC also retained Pb after sorption from water, with subsequent losses of ≤8.5% of total bound Pb. The proposed use of this material is for the filtration of PTE from extract solution following soil washing. Low-molecular-mass organic acids offer a less destructive, biodegradable alternative to strong inorganic acids for soil washing. PMID:26900684

  19. Preparation of a modified flue gas desulphurization residue and its effect on pot sorghum growth and acidic soil amelioration.

    PubMed

    Shi, Lin; Xu, Peizhi; Xie, Kaizhi; Tang, Shuanhu; Li, Yongli

    2011-09-15

    A modified flue gas desulphurization residue (MFGDR) was prepared and its effects on sorghum growth and acidic soil amelioration were evaluated in this paper. The MFGDR was prepared by calcining a mixture of dry/semi-dry flue gas desulphurization (FGD) residue from a coal-fired power plant, sorted potash feldspar and/or limestone powder. The available nutrients from the MFGDR were determined with 4.91 wt% K(+), 1.15 wt% Mg(2+), 22.4 wt% Ca(2+), 7.01 wt% Si(4+) and 2.07 wt% SO(4)(2-)-S in 0.1 mol L(-1) citric acid solution. Its pH value was held at 9.60 displaying slightly alkaline. The results of sorghum pot growth in both red and crimson acidic soil for 30 days indicated that adding the MFGDR at a dosage of 2 g kg(-1) in total soil weight would increase the growth rate of biomass by 24.3-149% (wet weight basis) and 47.3-157% (dry weight), the stem length and thickness increase by 5.75-22.1% and 4.76-30.9% in contrast with CK treatment for two test cuttings, respectively. The effect on sorghum growth was attributed to the increase of available nutrients, the enhancement of soil pH value and the reduction of aluminum toxicity in acidic soil due to the addition of the MFGDR. The experimental results also suggested that the MFGDR could be effectively used to ameliorate the acidic soil which is widely distributed throughout the southern China.

  20. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    NASA Astrophysics Data System (ADS)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

  1. Cadmium, lead and zinc leaching from smelter fly ash in simple organic acids--simulators of rhizospheric soil solutions.

    PubMed

    Ettler, Vojtech; Vrtisková, Růzena; Mihaljevic, Martin; Sebek, Ondrej; Grygar, Tomás; Drahota, Petr

    2009-10-30

    Emissions from base-metal smelters are responsible for high contamination of the surrounding soils. Fly ash from a secondary Pb smelter was submitted to a batch leaching procedure (0.5-168 h) in 500 microM solutions of acetic, citric, or oxalic acids to simulate the release of toxic metals (Cd, Pb, Zn) in rhizosphere-like environments. Organic acids increased dissolution of fly ash by a factor of 1.3. Cadmium and Pb formed mobile chloro- and sulphate-complexes, whereas Zn partly present in a citrate (Zn-citrate(-)) complex is expected to be less mobile due to sorption onto the positively charged surfaces of hydrous ferric oxides (HFO) and organic matter (OM) in acidic soil.

  2. Effects of simulated acid rain on microbial characteristics in a lateritic red soil.

    PubMed

    Xu, Hua-qin; Zhang, Jia-en; Ouyang, Ying; Lin, Ling; Quan, Guo-ming; Zhao, Ben-liang; Yu, Jia-yu

    2015-11-01

    A laboratory experiment was performed to examine the impact of simulated acid rain (SAR) on nutrient leaching, microbial biomass, and microbial activities in a lateritic red soil in South China. The soil column leaching experiment was conducted over a 60-day period with the following six SAR pH treatments (levels): 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 and one control treatment (pH = 7). Compared with the control treatment, the concentrations of soil organic matter, total nitrogen, total phosphorus, total potassium, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), and average well color density (AWCD) in the Ecoplates were all significantly decreased by leaching with SAR at different pH levels. The decrease in MBC and MBN indicated that acid rain reduced the soil microbial population, while the decrease in AWCD revealed that acid rain had a negative effect on soil bacterial metabolic function. Soil basal respiration increased gradually from pH 4.0 to 7.0 but decreased dramatically from pH 2.5 to 3.0. The decrease in soil nutrient was the major reason for the change of soil microbial functions. A principal component analysis showed that the major carbon sources used by the bacteria were carbohydrates and carboxylic acids.

  3. Ammonia-oxidizing activity and microbial community structure in acid tea (Camellia sinensis) orchard soil

    NASA Astrophysics Data System (ADS)

    Okamura, K.; Takanashi, A.; Yamada, T.; Hiraishi, A.

    2012-03-01

    The purpose of this study was to determine the ammonia-oxidizing activity and the phylogentic composition of microorganisms involved in acid tea (Camellia sinensis) orchard soil. All soil samples were collected from three sites located in Tahara and Toyohashi, Aichi Prefecture, Japan. The potential nitrification rate (PNR) was measured by the chlorate inhibition method. The soil pH of tea orchards studied ranged from 2.78 to 4.84, differing significantly from sample to sample, whereas that of meadow and unplanted fields ranged from 5.78 to 6.35. The PNR ranged from 0.050 to 0.193 μg NO2--Ng-1 h-1 and were positively correlated with the soil pH (r2 = 0.382, p<0.001). Bulk DNA was extracted from a tea orchard soil (pH 4.8; PNR, 0.078 μg NO2--Ng-1 h-1) and subjected to PCR-aided clone library analyses targeting archaeal and bacterial amoA genes. The detected archaeal clones separated from the cluster of the 'Soil clones' and tightly clustered with the clones originating from other acidic soil environments including the Chinese tea orchard soil. These results suggest that the specific archaeal populations dominate as the ammonia oxidizers in acid tea-orchard soils and possibly other acid soils, independent of geographic locations, which results from the adaptation to specific ecological niches.

  4. Air-pollution emission control in China: impacts on soil acidification recovery and constraints due to drought.

    PubMed

    Duan, Lei; Liu, Jing; Xin, Yan; Larssen, Thorjørn

    2013-10-01

    The Chinese government has established compulsory targets to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions by 8% and 10%, respectively, during 2010-2015. In this study, the effect of the policy was evaluated by predicting the recovery of acidified forest soil in Chongqing, an area severely impacted by acid rain in southwest China. Since precipitation has decreased significantly in this area in recent years, the impact of drought on soil acidification was also considered. A dynamic acidification model, MAGIC, was used to predict future trends in soil chemistry under different scenarios for deposition reduction as well as drought. We found that the current regulation of SO2 emission abatement did not significantly increase soil water pH values, the Ca2+ to Al3+ molar ratio (Ca/Al), or soil base saturation to the level of 2000 before 2050. NOx emission control would have less of an effect on acidification recovery, while emission reduction of particulate matter could offset the benefits of SO2 reduction by greatly decreasing the deposition of base cations, particularly Ca(2+). Continuous droughts in the future might also delay acidification recovery. Therefore, more stringent SO2 emission control should be implemented to facilitate the recovery of seriously acidified areas in China.

  5. Environmental distribution and associated human health risk due to trace elements and organic compounds in soil in Jiangxi province, China.

    PubMed

    Teng, Yanguo; Li, Jiao; Wu, Jin; Lu, Sijin; Wang, Yeyao; Chen, Haiyang

    2015-12-01

    The government of China launched its first national soil quality and pollution survey (NSQPS) during April 2006 to December 2013. Data gathered in several earlier soil surveys were rarely used to understand the status of pollution. In this study, the dataset collected at the provincial level was analyzed for the first time. Concentrations, distribution, diversity, and human health risks of trace elements (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Se, V and Zn) and organic pollutants (benzene hexachloride (BHCs), dichlorodiphenyltrichloroethanes (DDTs), phthalic acid esters (PAEs), polycyclic aromatic hydrocarbon (PAHs), polychlorinated biphenyls (PCBs), and petroleum hydrocarbons (PHCs)) in surface soil samples collected across Jiangxi province,China were presented. The results showed that, the proportion of contaminants with concentrations higher than their corresponding regulatory reference value ranged from 0.12% to 17%. It is worth note that, the local residents are exposed to moderate non-carcinogenic and carcinogenic risks at some sites. The comprehensive analysis of soil pollutants provide baseline information for establishing a long-term soil environmental monitoring program in Jiangxi province, China.

  6. Monitoring the Perturbation of Soil and Groundwater Microbial Communities Due to Pig Production Activities

    PubMed Central

    Hong, Pei-Ying; Yannarell, Anthony C.; Dai, Qinghua; Ekizoglu, Melike

    2013-01-01

    This study aimed to determine if biotic contaminants originating from pig production farms are disseminated into soil and groundwater microbial communities. A spatial and temporal sampling of soil and groundwater in proximity to pig production farms was conducted, and quantitative PCR (Q-PCR) was utilized to determine the abundances of tetracycline resistance genes (i.e., tetQ and tetZ) and integrase genes (i.e., intI1 and intI2). We observed that the abundances of tetZ, tetQ, intI1, and intI2 in the soils increased at least 6-fold after manure application, and their abundances remained elevated above the background for up to 16 months. Q-PCR further determined total abundances of up to 5.88 × 109 copies/ng DNA for tetZ, tetQ, intI1, and intI2 in some of the groundwater wells that were situated next to the manure lagoon and in the facility well used to supply water for one of the farms. We further utilized 16S rRNA-based pyrosequencing to assess the microbial communities, and our comparative analyses suggest that most of the soil samples collected before and after manure application did not change significantly, sharing a high Bray-Curtis similarity of 78.5%. In contrast, an increase in Bacteroidetes and sulfur-oxidizing bacterial populations was observed in the groundwaters collected from lagoon-associated groundwater wells. Genera associated with opportunistic human and animal pathogens, such as Acinetobacter, Arcobacter, Yersinia, and Coxiella, were detected in some of the manure-treated soils and affected groundwater wells. Feces-associated bacteria such as Streptococcus, Erysipelothrix, and Bacteroides were detected in the manure, soil, and groundwater ecosystems, suggesting a perturbation of the soil and groundwater environments by invader species from pig production activities. PMID:23396341

  7. Bioaccumulation of perfluoroalkyl acids by earthworms (Eisenia fetida) exposed to contaminated soils.

    PubMed

    Rich, Courtney D; Blaine, Andrea C; Hundal, Lakhwinder; Higgins, Christopher P

    2015-01-20

    The presence of perfluoroalkyl acids (PFAAs) in biosolids-amended and aqueous film-forming foam (AFFF)-impacted soils results in two potential pathways for movement of these environmental contaminants into terrestrial foodwebs. Uptake of PFAAs by earthworms (Eisenia fetida) exposed to unspiked soils with varying levels of PFAAs (a control soil, an industrially impacted biosolids-amended soil, a municipal biosolids-amended soil, and two AFFF-impacted soils) was measured. Standard 28 day exposure experiments were conducted in each soil, and measurements taken at additional time points in the municipal soil were used to model the kinetics of uptake. Uptake and elimination rates and modeling suggested that steady state bioaccumulation was reached within 28 days of exposure for all PFAAs. The highest concentrations in the earthworms were for perfluorooctane sulfonate (PFOS) in the AFFF-impacted Soil A (2160 ng/g) and perfluorododecanoate (PFDoA) in the industrially impacted soil (737 ng/g). Wet-weight (ww) and organic carbon (OC)-based biota soil accumulation factors (BSAFs) for the earthworms were calculated after 28 days of exposure for all five soils. The highest BSAF in the industrially impacted soil was for PFDoA (0.42 goc/gww,worm). Bioaccumulation factors (BAFs, dry-weight-basis, dw) were also calculated at 28 days for each of the soils. With the exception of the control soil and perfluorodecanoate (PFDA) in the industrially impacted soil, all BAF values were above unity, with the highest being for perfluorohexanesulfonate (PFHxS) in the AFFF-impacted Soil A (139 gdw,soil/gdw,worm). BSAFs and BAFs increased with increasing chain length for the perfluorocarboxylates (PFCAs) and decreased with increasing chain length for the perfluoroalkyl sulfonates (PFSAs). The results indicate that PFAA bioaccumulation into earthworms depends on soil concentrations, soil characteristics, analyte, and duration of exposure, and that accumulation into earthworms may be a potential

  8. Alleviating aluminium toxicity on an acid sulphate soils in Peninsular Malaysia with application of calcium silicate

    NASA Astrophysics Data System (ADS)

    Elisa, A. A.; Ninomiya, S.; Shamshuddin, J.; Roslan, I.

    2015-10-01

    A study was conducted to alleviate Al toxicity of an acid sulphate soils collected from paddy cultivation area in Kedah, Peninsular Malaysia. For this purpose, the collected acid sulphate soils were treated with calcium silicate. The treated soils were incubated for 120 days in submerged condition in a glasshouse. Subsamples were collected every 30 days throughout the incubation period. Soil pH and exchangeable Al showed positive effect; soil pH increased from 2.9 to 3.5, meanwhile exchangeable Al was reduced from 4.26 to 0.82 cmolc kg-1, which was well below the critical Al toxicity level for rice growth of 2 cmolc kg-1. It was noted that the dissolution of calcium silicate (CaSiO3) supplied substantial amount of Ca2+ and H4SiO42- ions into the soil, noted with increment in Si (silicate) content from 21.21 to 40 mg kg-1 at day 30 and reduction of exchangeable Al at day 90 from 4.26 to below 2 cmolc kg-1. During the first 60 days of incubation, Si content was positively correlated with soil pH, while the exchangeable Al was negatively correlated with Si content. It is believed that the silicate anions released by calcium silicate were active in neutralizing H+ ions that governs the high acidity (pH 2.90) of the acid sulphate soils. This scenario shows positive effect of calcium silicate to reduce soil acidity, therefore creates a favourable soil condition for good rice growth during its vegetative phase (30 days). Thus, application of calcium silicate to alleviate Al toxicity of acid sulphate soils for rice cultivation is a good soil amendment.

  9. Remediation of Pb-contaminated soils by washing with hydrochloric acid and subsequent immobilization with calcite and allophanic soil.

    PubMed

    Isoyama, Masahiro; Wada, Shin-Ichiro

    2007-05-17

    Removal of heavy metals from contaminated soil is not popular because of its high cost. Reducing the bioaccessible heavy metals content to an allowable level by washing with inorganic acids and subsequent immobilization of remained metals may be a low cost option for soil remediation. The applicability of this combined treatment was investigated using three different types of soil, a kaolinitic, a smectitic and an allophanic soil, which were artificially contaminated with Pb. The effectiveness of the treatment was evaluated using two main criteria: (i) reduction of the HCl extractable Pb (bioaccessible Pb) below 150 mg kg(-1), reduction of water extractable Pb below the concentration of 0.01 mg L(-1). These values correspond to allowable levels suggested by the Japanese Ministry of Environment. The soils were washed batch-wise at a solution to soil ratio of 5 L kg(-1) successively with 1 mol L(-1) HCl and 0.1 mol L(-1) CaCl(2) solutions. The two solutions were separated by filtration from one batch and reused for washing the next batch of soil without processing. The Pb concentration in the solutions increased after repeated use and removal efficiency gradually declined. The efficiency of the treatment was highly dependent on the type of soil. In the kaolinitic soil, HCl extractable Pb content of the soil from the first batch was about 50 mg kg(-1) and it exceeded 150 mg kg(-1) in that from sixth batch. But the combined soils from 1st to 10th batches gave bioaccessible Pb content barely below 150 mg kg(-1). For the smectitic soil having higher cation exchange capacity, the acceptable number of times of reuse was estimated to be 4. For the allophanic soil, treatment with the HCl solution was efficient only for the first batch of the soil, and the reuse of the acid solution was found to be ineffective. The application of 50 g kg(-1) of calcite or slacked lime was effective for reducing the water extractable Pb content. To keep soil pH near neutral and secure long

  10. Evolution of unsaturated hydraulic conductivity of aggregated soils due to compressive forces

    NASA Astrophysics Data System (ADS)

    Berli, M.; Carminati, A.; Ghezzehei, T. A.; Or, D.

    2008-05-01

    Prediction of water flow and transport processes in soils susceptible to structural alteration such as compaction of tilled agricultural lands or newly constructed landfills rely on accurate description of changes in soil unsaturated hydraulic conductivity. Recent studies have documented the critical impact of aggregate contact characteristics on water flow rates and pathways in unsaturated aggregated soils. We developed an analytical model for aggregate contact size evolution as a basis for quantifying effects of compression on saturated and unsaturated hydraulic conductivity of aggregated soil. Relating confined one-dimensional sample strain with aggregate deformation facilitates prediction of the increase in interaggregate contact area and concurrent decrease in macropore size with degree of sample compression. The hydrologic component of the model predicts unsaturated hydraulic conductivity of a pack of idealized aggregates (spheres) on the basis of contact size and saturation conditions under prescribed sample deformation. Calculated contact areas and hydraulic conductivity for pairs of aggregates agreed surprisingly well with measured values, determined from compaction experiments employing neutron and X-ray-radiography and image analysis. Model calculations for a unit cell of uniform spherical aggregates in cubic packing were able to mimic some of the differences in saturated and unsaturated hydraulic conductivity observed for aggregates and bulk soil.

  11. [Effects of soil acidity on Pinus resinosa seedlings photosynthesis and chlorophyll fluorescence].

    PubMed

    Liu, Shuang; Wang, Qing-cheng; Liu, Ya-li; Tian, Yu-ming; Sun, Jing; Xu, Jing

    2009-12-01

    Red pine (Pinus resinosa) is one of the most important tree species for timber plantation in North America, and preliminary success has been achieved in its introduction to the mountainous area of Northeast China since 2004. In order to expand its growth area in other parts of Northeast China, a pot experiment was conducted to study the adaptability of this tree species to varying soil acidity. P. resinosa seedlings were grown in soils with different acidity (pH = 4.5, 5.5, 6.5, 7.5, and 8.0) to test the responses of their photosynthesis and chlorophyll fluorescence parameters to soil pH levels, and the appropriate soil acidity was evaluated. Dramatic responses in chlorophyll a and b contents, Pn and chlorophyll fluorescence parameters (Fo, Fm, Fv, Fv/Fm, and phi(PS II)) were detected under different soil acidity (P < 0.05), with the highest chlorophyll content and Pn under soil pH 5.5, and significantly lower chlorophyll content and Pn under soil pH 7.5 and 8.0. The chlorophyll content and Pn were 41% and 50%, and 61% and 88% higher under soil pH 5.5 than under soil pH 7.5 and 8.0. The seedlings had a significant photosynthetic inhibition under soil pH 7.5 and 8.0, but the highest Fv/Fm and phi (PS II) under soil pH 5.5. Comparing with those under soil pH 7.5 and 8.0, the Fv/Fm and phi (PS II) under soil pH 5.5 were 8% and 12%, and 22% and 35% higher, respectively. It was suggested that soil pH 5.5 was most appropriate for P. resinosa growth.

  12. An acid-tolerant ammonia-oxidizing γ-proteobacterium from soil.

    PubMed

    Hayatsu, Masahito; Tago, Kanako; Uchiyama, Ikuo; Toyoda, Atsushi; Wang, Yong; Shimomura, Yumi; Okubo, Takashi; Kurisu, Futoshi; Hirono, Yuhei; Nonaka, Kunihiko; Akiyama, Hiroko; Itoh, Takehiko; Takami, Hideto

    2017-01-10

    Nitrification, the microbial oxidation of ammonia to nitrate via nitrite, occurs in a wide range of acidic soils. However, the ammonia-oxidizing bacteria (AOB) that have been isolated from soil to date are acid-sensitive. Here we report the isolation and characterization of an acid-adapted AOB from an acidic agricultural soil. The isolated AOB, strain TAO100, is classified within the Gammaproteobacteria based on phylogenetic characteristics. TAO100 can grow in the pH range of 5-7.5 and survive in highly acidic conditions until pH 2 by forming cell aggregates. Whereas all known gammaproteobacterial AOB (γ-AOB) species, which have been isolated from marine and saline aquatic environments, are halophiles, TAO100 is not phenotypically halophilic. Thus, TAO100 represents the first soil-originated and non-halophilic γ-AOB. The TAO100 genome is considerably smaller than those of other γ-AOB and lacks several genes associated with salt tolerance which are unnecessary for survival in soil. The ammonia monooxygenase subunit A gene of TAO100 and its transcript are higher in abundance than those of ammonia-oxidizing archaea and betaproteobacterial AOB in the strongly acidic soil. These results indicate that TAO100 plays an important role in the nitrification of acidic soils. Based on these results, we propose TAO100 as a novel species of a new genus, Candidatus Nitrosoglobus terrae.The ISME Journal advance online publication, 10 January 2017; doi:10.1038/ismej.2016.191.

  13. The effect of acidity on the distribution and symbiotic efficiency of rhizobia in Lithuanian soils

    NASA Astrophysics Data System (ADS)

    Lapinskas, E. B.

    2007-04-01

    The distribution and symbiotic efficiency of nodule bacteria Rhizobium leguminosarum_bv. trifolii F., Sinorhizobium meliloti D., Rhizobium galegae L., and Rhizobium leguminosarum bv. viciae F. in Lithuanian soils as dependent on the soil acidity were studied in the long-term field, pot, and laboratory experiments. The critical and optimal pH values controlling the distribution of rhizobia and the symbiotic nitrogen fixation were determined for every bacterial species. The relationship was found between the soil pH and the nitrogen-fixing capacity of rhizobia. A positive effect of liming of acid soils in combination with inoculation of legumes on the efficiency of symbiotic nitrogen fixation was demonstrated.

  14. Invasion of a semi-arid shrubland by annual grasses increases autotrophic and heterotrophic soil respiration rates due to altered soil moisture and temperature patterns

    NASA Astrophysics Data System (ADS)

    Mauritz, M.; Hale, I.; Lipson, D.

    2010-12-01

    Shrub <-> grassland conversions are a globally occurring phenomenon altering habitat structure, quality and nutrient cycling. Grasses and shrubs differ in their above and belowground biomass allocation, root architecture, phenology, litter quality and quantity. Conversion affects soil microbial communities, soil moisture and temperature and carbon (C) allocation patterns. However, the effect of conversion on C storage is regionally variable and there is no consistent direction of change. In Southern California invasion by annual grasses is a major threat to native shrub communities and it has been proposed that grass invasion increases NPP and ecosystem C storage (Wolkovich et al, 2009). In order to better understand how this shrub <-> grassland conversion changes ecosystem C storage it is important to understand the partitioning of soil respiration into autotrophic and heterotrophic components. Respiration was measured in plots under shrubs and grasses from February when it was cold and wet to July when it was hot and dry, capturing seasonal transitions in temperature and water availability. Roots were excluded under shrubs and grasses with root exclusion cores to quantify heterotrophic respiration. Using total soil respiration (Rt) = autotrophic respiration (root) (Ra)+ heterotrophic respiration (microbial) (Rh) the components contributing to total soil respiration can be evaluated. Respiration, soil moisture and temperature were measured daily at four hour intervals using Licor 8100 automated chamber measurements. Throughout the measurement period, Rt under grasses exceeded Rt under shrubs. Higher Rt levels under grasses were mainly due to higher Ra in grasses rather than changes in Rh. On average grass Ra was almost double shrub Ra. Higher grass respiration levels are partially explained by differences in soil moisture and temperature between shrubs and grasses. Respiration rates responded similarly to seasonal transitions regardless of treatment although Ra

  15. Persistent episodic acidification of streams linked to acid rain effects on soil

    USGS Publications Warehouse

    Lawrence, G.B.

    2002-01-01

    Episodic acidification of streams, identified in the late 1980s as one of the most significant environmental problems caused by acidic deposition, had not been evaluated since the early 1990s despite decreasing levels of acidic deposition over the past decade. This analysis indicates that episodic acidification of streams in upland regions in the northeastern United States persists, and is likely to be much more widespread than chronic acidification. Depletion of exchangeable Ca in the mineral soil has decreased the neutralization capacity of soils and increased the role of the surface organic horizon in the neutralization of acidic soil water during episodes. Increased accumulation of N and S in the forest floor from decades of acidic deposition will delay the recovery of soil base status, and therefore, the elimination of acidic episodes, which is anticipated from decreasing emissions.

  16. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS: DETECTION AND QUANTITATION ISSUES AT LOW CONCENTRATIONS

    EPA Science Inventory

    Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorinated octanoic acid (PFOA), perfluorinated nonanoic acid (PFNA) and perfluorinated decanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can...

  17. Effects of dicyandiamide and dolomite application on N2O emission from an acidic soil.

    PubMed

    Shaaban, Muhammad; Wu, Yupeng; Peng, Qi-an; Lin, Shan; Mo, Yongliang; Wu, Lei; Hu, Ronggui; Zhou, Wei

    2016-04-01

    Soil acidification is a major problem for sustainable agriculture since it limits productivity of several crops. Liming is usually adopted to ameliorate soil acidity that can trigger soil processes such as nitrification, denitrification, and loss of nitrogen (N) as nitrous oxide (N2O) emissions. The loss of N following liming of acidic soils can be controlled by nitrification inhibitors (such as dicyandiamide). However, effects of nitrification inhibitors following liming of acidic soils are not well understood so far. Here, we conducted a laboratory study using an acidic soil to examine the effects of dolomite and dicyandiamide (DCD) application on N2O emissions. Three levels of DCD (0, 10, and 20 mg kg(-1); DCD0, DCD10, and DCD20, respectively) were applied to the acidic soil under two levels of dolomite (0 and 1 g kg(-1)) which were further treated with two levels of N fertilizer (0 and 200 mg N kg(-1)). Results showed that N2O emissions were highest at low soil pH levels in fertilizer-treated soil without application of DCD and dolomite. Application of DCD and dolomite significantly (P ≤ 0.001) reduced N2O emissions through decreasing rates of NH4 (+)-N oxidation and increasing soil pH, respectively. Total N2O emissions were reduced by 44 and 13% in DCD20 and dolomite alone treatments, respectively, while DCD20 + dolomite reduced N2O emissions by 54% when compared with DCD0 treatment. The present study suggests that application of DCD and dolomite to acidic soils can mitigate N2O emissions.

  18. A Petroleum Vapor Intrusion Model Involving Upward Advective Soil Gas Flow Due to Methane Generation.

    PubMed

    Yao, Yijun; Wu, Yun; Wang, Yue; Verginelli, Iason; Zeng, Tian; Suuberg, Eric M; Jiang, Lin; Wen, Yuezhong; Ma, Jie

    2015-10-06

    At petroleum vapor intrusion (PVI) sites at which there is significant methane generation, upward advective soil gas transport may be observed. To evaluate the health and explosion risks that may exist under such scenarios, a one-dimensional analytical model describing these processes is introduced in this study. This new model accounts for both advective and diffusive transport in soil gas and couples this with a piecewise first-order aerobic biodegradation model, limited by oxygen availability. The predicted results from the new model are shown to be in good agreement with the simulation results obtained from a three-dimensional numerical model. These results suggest that this analytical model is suitable for describing cases involving open ground surface beyond the foundation edge, serving as the primary oxygen source. This new analytical model indicates that the major contribution of upward advection to indoor air concentration could be limited to the increase of soil gas entry rate, since the oxygen in soil might already be depleted owing to the associated high methane source vapor concentration.

  19. Alleviating aluminum toxicity in an acid sulfate soil from Peninsular Malaysia by calcium silicate application

    NASA Astrophysics Data System (ADS)

    Elisa, A. A.; Ninomiya, S.; Shamshuddin, J.; Roslan, I.

    2016-03-01

    In response to human population increase, the utilization of acid sulfate soils for rice cultivation is one option for increasing production. The main problems associated with such soils are their low pH values and their associated high content of exchangeable Al, which could be detrimental to crop growth. The application of soil amendments is one approach for mitigating this problem, and calcium silicate is an alternative soil amendment that could be used. Therefore, the main objective of this study was to ameliorate soil acidity in rice-cropped soil. The secondary objective was to study the effects of calcium silicate amendment on soil acidity, exchangeable Al, exchangeable Ca, and Si content. The soil was treated with 0, 1, 2, and 3 Mg ha-1 of calcium silicate under submerged conditions and the soil treatments were sampled every 30 days throughout an incubation period of 120 days. Application of calcium silicate induced a positive effect on soil pH and exchangeable Al; soil pH increased from 2.9 (initial) to 3.5, while exchangeable Al was reduced from 4.26 (initial) to 0.82 cmolc kg-1. Furthermore, the exchangeable Ca and Si contents increased from 1.68 (initial) to 4.94 cmolc kg-1 and from 21.21 (initial) to 81.71 mg kg-1, respectively. Therefore, it was noted that calcium silicate was effective at alleviating Al toxicity in acid sulfate, rice-cropped soil, yielding values below the critical level of 2 cmolc kg-1. In addition, application of calcium silicate showed an ameliorative effect as it increased soil pH and supplied substantial amounts of Ca and Si.

  20. The effects of woodchip- and straw-derived biochars on the persistence of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in soils.

    PubMed

    Muter, Olga; Berzins, Andrejs; Strikauska, Silvija; Pugajeva, Iveta; Bartkevics, Vadims; Dobele, Galina; Truu, Jaak; Truu, Marika; Steiner, Christoph

    2014-11-01

    Sorption and degradation are the primary processes controlling the efficacy and runoff contamination risk of agrochemicals. This study assessed the influence of two biochars, made from woodchips and straw at a pyrolysis temperature of 725°C and applied to a loamy sand and a sandy soil in the concentration of 5.3 g 100 g(-1) sandy soil and 4.1 g 100 g(-1) loamy sand soil, or 53 t ha(-1) for both soil types, on degradation of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA). Soils were spiked with 50 mg MCPA kg(-1) soil. In the sandy soil, significantly more MCPA remained after 100 days if amended with straw-derived biochar in comparison to wood-derived biochar. Both biochars types significantly increased urease activity (p<0.05) after 37 days in the loamy sand soil, but these differences disappeared after 100 days. A root and shoot elongation test demonstrated that the soils containing straw-derived biochar and spiked with MCPA, showed the highest phytotoxicity. Both biochars were found to retard MCPA degradation in loamy sand and sandy soils. This effect could not be explained only by sorption processes due to comparatively low developed micro/mesoporous structure of both biochars shown by BET surface analysis. However, an enhanced MCPA persistence and soil toxicity in sandy soil amended with straw biochar was observed and further studies are needed to reveal the responsible mechanisms.

  1. Potential origin and formation for molecular components of humic acids in soils

    NASA Astrophysics Data System (ADS)

    DiDonato, Nicole; Chen, Hongmei; Waggoner, Derek; Hatcher, Patrick G.

    2016-04-01

    Soil humic acids are the base soluble/acid insoluble organic components of soil organic matter. Most of what we know about humic acids comes from studies of their bulk molecular properties or analysis of individual fractions after extraction from soils. This work attempts to better define humic acids and explain similarities and differences for several soils varying in degrees of humification using advanced molecular level techniques. Our investigation using electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) and nuclear magnetic resonance spectroscopy (NMR) has given new insight into the distinctive molecular characteristics of humic acids which suggest a possible pathway for their formation. Humic acids from various ecosystems, climate regions and soil textural classes are distinguished by the presence of three predominant molecular components: lignin-like molecules, carboxyl-containing aliphatic molecules and condensed aromatic molecules that bear similarity to black carbon. Results show that humification may be linked to the relative abundance of these three types of molecules as well as the relative abundance of carboxyl groups in each molecular type. This work also demonstrates evidence for lignin as the primary source of soil organic matter, particularly condensed aromatic molecules often categorized as black carbon and is the first report of the non-pyrogenic source for these compounds in soils. We also suggest that much of the carboxyl-containing aliphatic molecules are sourced from lignin.

  2. Localized application of soil organic matter shifts distribution of cluster roots of white lupin in the soil profile due to localized release of phosphorus

    PubMed Central

    Li, Hai-Gang; Shen, Jian-Bo; Zhang, Fu-Suo; Lambers, Hans

    2010-01-01

    Background and Aims Phosphorus (P) is a major factor controlling cluster-root formation. Cluster-root proliferation tends to concentrate in organic matter (OM)-rich surface-soil layers, but the nature of this response of cluster-root formation to OM is not clear. Cluster-root proliferation in response to localized application of OM was characterized in Lupinus albus (white lupin) grown in stratified soil columns to test if the stimulating effect of OM on cluster-root formation was due to (a) P release from breakdown of OM; (b) a decrease in soil density; or (c) effects of micro-organisms other than releasing P from OM. Methods Lupin plants were grown in three-layer stratified soil columns where P was applied at 0 or 330 mg P kg−1 to create a P-deficient or P-sufficient background, and OM, phytate mixed with OM, or perlite was applied to the top or middle layers with or without sterilization. Key Results Non-sterile OM stimulated cluster-root proliferation and root length, and this effect became greater when phytate was supplied in the presence of OM. Both sterile OM and perlite significantly decreased cluster-root formation in the localized layers. The OM position did not change the proportion of total cluster roots to total roots in dry biomass among no-P treatments, but more cluster roots were concentrated in the OM layers with a decreased proportion in other places. Conclusions Localized application of non-sterile OM or phytate plus OM stimulated cluster-root proliferation of L. albus in the localized layers. This effect is predominantly accounted for by P release from breakdown of OM or phytate, but not due to a change in soil density associated with OM. No evidence was found for effects of micro-organisms in OM other than those responsible for P release. PMID:20150198

  3. Dose-response functions for the soiling of heritage materials due to air pollution exposure.

    PubMed

    Watt, John; Jarrett, David; Hamilton, Ron

    2008-08-01

    A set of materials (Portland limestone, white painted steel, white plastic and polycarbonate filter material) was exposed at locations in London, Athens and Krakow. Regular measurements of reflectance were taken over a period of twelve months. Co-located measurements of PM(10) concentrations were available. Based on these results, the relationship between soiling (measured as loss of reflectance) and ambient PM(10) concentrations was quantified leading to the development of dose-response functions for the soiling of materials. The results for limestone revealed too much scatter for a prediction to be made. Implications for air quality management and for the conservation of cultural heritage buildings are considered, including public acceptability and economic factors.

  4. P Limitation and Microbial Biogeochemistry in Acidic Forest Soils of the Northeastern United States

    NASA Astrophysics Data System (ADS)

    Smemo, K. A.; Deforest, J. L.; Burke, D. J.; Elliot, H. L.; Kluber, L. A.; Carrino-Kyker, S. R.

    2010-12-01

    In forest ecosystems with acidic soils, such as many hardwood forests of the Northeastern United States, net primary productivity should be limited by phosphorus (P) because P is biologically less available at pH < 5 and nitrogen (N) has become more abundant in response to anthropogenic inputs. However, previous studies have failed to demonstrate widespread P limitation in temperate forests that have naturally acidic soil or are exposed to chronic acid deposition; such findings are contrary to biogeochemical expectations. We hypothesize that many eastern forests possess an underlying P limitation not realized at the ecosystem level. Instead, shifts in the composition, structure and function of soil microbial communities compensate by acquiring more P from organic sources and P limitation is therefore not manifested at the aboveground (plant) level. To test this hypothesis, we manipulated soil pH and P availability in 72 20 x 40 m mature hardwood forest plots across northeastern (glaciated) and southeastern (unglaciated) Ohio beginning in late summer 2009. Ten months after treatment initiation, soil pH has increased from 4.5 to 5.5 and soil P has increased from 3 to ~25 mg P/kg soil on glaciated soils and from 0.5 to ~5 mg P/kg soil on unglaciated soils. To quantify treatment responses, we measured the activity of soil extracellular enzymes associated with liberation of P, N, and C from organic matter, as well as pools of N and N cycling processes. We saw no significant effects of our treatments on pools of available ammonium or nitrate, nor did we see effects on net N mineralization and net nitrification rates. However, glaciated soils had significantly greater nitrate pools and higher N cycling rates than older unglaciated soils. Nitrogen and C cycling enzymes in treatment plots were not significantly different than control plots, but N-acetylglucosaminidase activity (N acquisition) was significantly greater in the unglaciated soils and β-glucosidase and

  5. Sediments deposition due to soil erosion in the watershed region of Mangla dam.

    PubMed

    Butt, Mohsin Jamil; Mahmood, Rashed; Waqas, Ahmad

    2011-10-01

    Soil erosion is the most important reason of sedimentation load of water reservoirs in the world. In Pakistan, Mangla dam is one of the most important water reservoirs used for the production of electricity and for the supply of water for irrigation purposes. However, the capacity of Mangla dam reservoir has reduced by more than 20% since its construction. This study highlights the impact of rainfall on soil erosion and consequently on sedimentation deposition in Mangla dam reservoir. Sedimentation, annual rainfall, and normal rainfall data of 39 years were used in this study. Shuttle Radar Topographic Mission data were used to calculate the total drainage area of the Mangla watershed region. The sedimentation data of Mangla reservoir from 1967 to 2005 were retrieved from Water and Power Development Authority in Pakistan. The meteorological observatories in the Mangla watershed region are identified. Annual rainfall data from 1967 to 2005 for the meteorological observatories in the Mangla watershed regions were retrieved from Pakistan Meteorological Department (PMD). In addition, normal rainfall data for the years 1949 to 1978 and for the years 1979 to 2008 were also retrieved from PMD. The impact of annual rainfall is observed on sedimentation load in Mangla dam. The correlation coefficient between annual rainfall and sedimentation load is 0.94. This study shows that with an increase in rainfall, the soil erosion of the area increases which subsequently is responsible for the increase in the rate of sedimentation load in Mangla dam. This study further demonstrates that better soil management can reduce the sedimentation load in the Mangla reservoir.

  6. Understanding the effect low molecular weight organic acids on the desorption and availability of soil phosphorus

    NASA Astrophysics Data System (ADS)

    Blackburn, Daniel; Zhang, Hao; Stutter, Marc; Giles, Courtney; George, Timothy; Shand, Charles; Lumsdon, David; Cooper, Pat; Wendler, Renate; Brown, Lawrie; Blackwell, Martin; Darch, Tegan; Wearing, Catherine; Haygarth, Philip

    2016-04-01

    The mobility and resupply of inorganic phosphorus (P) from the soil solid phase after equilibration with increasing doses of citric acid (CA) and oxalic acid (OA) were studied in 2 soils with contrasting P status. The combined methods of diffusive gradients in thin films (DGT), diffusive equilibration in thin films (DET) and the DGT-induced fluxes in sediments model (DIFS) were used as tools to evaluate the changes in solid-to-solution interchange kinetics. A significant effect of CA and OA in soil solution P was observed only for doses over 1 mMol kg-1. Curiously, low organic acid doses (0.5-1 mMol kg-1) were associated with a steep increase in microbial biomass P, which was not seen for doses over 2 mMol kg-1. The trivalent CA was able to promote a higher increase in soil solution P than the bivalent OA for both soils. Organic phosphorus was only significantly mobilized by organic acids in the low P soil, possibly because in the high P soil these P forms were less labile than inorganic P. Both CA and OA promoted a decrease in the adsorbed-to-solution distribution coefficient, desorption rate constants and an increase in the response time of solution P equilibration. The extent of this effect was shown to be both soil specific and organic acid specific. Since both organic acids negatively affected the kinetics of P interchange between the soil matrix and the soil solution, their net effect on P bioavailability is expected to be much lower than the observed increase in solution concentration.

  7. Global pattern of soil carbon losses due to the conversion of forests to agricultural land.

    PubMed

    Wei, Xiaorong; Shao, Mingan; Gale, William; Li, Linhai

    2014-02-11

    Several reviews have analyzed the factors that affect the change in soil organic C (SOC) when forest is converted to agricultural land; however, the effects of forest type and cultivation stage on these changes have generally been overlooked. We collated observations from 453 paired or chronosequential sites where forests have been converted to agricultural land and then assessed the effects of forest type, cultivation stage, climate factors, and soil properties on the change in the SOC stock and the SOC turnover rate constant (k). The percent decrease in SOC stocks and the turnover rate constants both varied significantly according to forest type and cultivation stage. The largest decrease in SOC stocks was observed in temperate regions (52% decrease), followed by tropical regions (41% decrease) and boreal regions (31% decrease). Climate and soil factors affected the decrease in SOC stocks. The SOC turnover rate constant after the conversion of forests to agricultural land increased with the mean annual precipitation and temperature. To our knowledge, this is the first time that original forest type was considered when evaluating changes in SOC after being converted to agricultural land. The differences between forest types should be considered when calculating global changes in SOC stocks.

  8. Historical arsenic contamination of soil due to long-term phosphate fertiliser applications.

    PubMed

    Hartley, Tom N; Macdonald, Andy J; McGrath, Steve P; Zhao, Fang-Jie

    2013-09-01

    Archived samples from the Park Grass Experiment, established in 1856, were analysed to determine the impacts of long-term phosphate fertiliser applications on arsenic concentrations in soil and herbage. In plots receiving 35 kg P ha(-1) annually (+P), topsoil As concentrations almost doubled from an initial value of ∼10 mg kg(-1) during 1888-1947 and remained stable thereafter. The phosphate fertilisers used before 1948 contained 401-1575 mg As kg(-1), compared to 1.6-20.3 mg As kg(-1) in the later samples. Herbage samples from the +P plots collected during 1888-1947 contained significantly more As than those from the -P plots, but later samples did not differ significantly. Mass-balance calculations show that the increase in soil As can be explained by the As input from P fertiliser applications before 1948. The results demonstrate that the P fertilisers used on the Park Grass Experiment before 1948 caused substantial As contamination of the soil.

  9. Effect of two different composts on soil quality and on the growth of various plant species in a polymetallic acidic mine soil.

    PubMed

    Rossini-Oliva, S; Mingorance, M D; Peña, A

    2017-02-01

    The effect of the addition (0-10%) of two types of sewage sludge composts (composted sewage sludge [CS] and sewage sludge co-composted with olive prune wastes [CSO]) on a polymetallic acidic soil from the Riotinto mining area was evaluated by i) a soil incubation experiment and ii) a greenhouse pot experiment using tomato (Solanum lycopersicum Mill.), ryegrass (Lolium perenne L.) and ahipa (Pachyrhizus ahipa (Wedd.) Parodi). Compost addition improved the soil organic carbon content, increased the pH and the electrical conductivity and enhanced enzyme activities and soil respiration, more for CSO than for CS. Plant growth was generally enhanced after compost addition, but not proportionally to the dose. Foliar concentrations of some hazardous elements (As, Cr, Fe) in tomato growing in non-amended soil were above the thresholds, questioning the adequacy of using this plant species. However, leaf concentrations of essential and potentially toxic elements (Fe, As, Cr and Pb) in tomato and/or ryegrass were reduced after the amendment with both composts, generally more for CSO than for CS. Conversely, foliar concentrations in ahipa, a plant species which is able to grow without the need of compost addition, were safe except for As and were only slightly affected by compost addition. This plant species would be a suitable candidate due to its low requirements and due to the limited element translocation to the leaves. Concerning the composts, amelioration of plant and soil properties was better accomplished when using CSO, a compost of sewage sludge and plant remains, than when using CS, which only contained the sludge.

  10. Mobilization of soil-borne arsenic by three common organic acids: Dosage and time effects.

    PubMed

    Onireti, Olaronke O; Lin, Chuxia

    2016-03-01

    A batch experiment was conducted to investigate the mobilization of soil-borne arsenic by three common low-molecular-weight organic acids with a focus on dosage and time effects. The results show that oxalic acid behaved differently from citric acid and malic acid in terms of mobilizing As that was bound to iron compounds. At an equivalent molar concentration, reactions between oxalic acid and soil-borne Fe were kinetically more favourable, as compared to those between either citric acid or malic acid and the soil-borne Fe. It was found that reductive dissolution of soil-borne Fe played a more important role in liberating As, as compared to non-reductive reactions. Prior to the 7th day of the experiment, As mobility increased with increasing dose of oxalic acid while there was no significant difference (P > 0.05) in mobilized As among the treatments with different doses of citric acid or malic acid. The dosage effect on soil-borne As mobilization in the citric acid and malic acid treatments became clear only after the 7th day of the experiment. Soluble Ca present in the soils could cause re-immobilization of As by competing with solution-borne Fe for available organic ligands to form practically insoluble organic compounds of calcium (i.e. calcium oxalate). This resulted in transformation of highly soluble organic complexes of iron (i.e. iron oxalate complexes) into slightly soluble organic compounds of iron (i.e. iron oxalate) or free ferric ion, which then reacted with the solution-borne arsenate ions to form practically insoluble iron arsenates in the latter part of the experiment.

  11. Effect of simulated acid rain on the litter decomposition of Quercus acutissima and Pinus massoniana in forest soil microcosms and the relationship with soil enzyme activities.

    PubMed

    Wang, Congyan; Guo, Peng; Han, Guomin; Feng, Xiaoguang; Zhang, Peng; Tian, Xingjun

    2010-06-01

    With the continuing increase in human activities, ecologists are increasingly interested in understanding the effects of acid rain on litter decomposition. Two dominant litters were chosen from Zijin Mountain in China: Quercus acutissima from a broad-leaved forest and Pinus massoniana from a coniferous forest. The litters were incubated in microcosms and treated with simulated acid rain (gradient pH levels). During a six-month incubation, changes in chemical composition (i.e., lignin, total carbohydrate, and nitrogen), litter mass losses, soil pH values, and activities of degradative enzymes were determined. Results showed that litter mass losses were depressed after exposure to acid rain and the effects of acid rain on the litter decomposition rates of needles were higher than on those of leaves. Results also revealed that simulated acid rain restrained the activities of cellulase, invertase, nitrate reductase, acid phosphatase, alkaline phosphatase, polyphenol oxidase, and urease, while it enhanced the activities of catalase in most cases during the six-month decomposition process. Catalase and polyphenol oxidase were primarily responsible for litter decomposition in the broad-leaved forest, while invertase, nitrate reductase, and urease were primarily responsible for litter decomposition in the coniferous forest. The results suggest acid rain-restrained litter decomposition may be due to the depressed enzymatic activities. According to the results of this study, soil carbon in subtropical forests would accumulate as a long-term consequence of continued acid rain. This may presumably alter the balance of ecosystem carbon flux, nutrient cycling, and humus formation, which may, in turn, have multiple effects on forest ecosystems.

  12. Influence of ingestion of aluminum, citric acid and soil on mineral metabolism of lactating beef cows.

    PubMed

    Allen, V G; Horn, F P; Fontenot, J P

    1986-05-01

    Lactating beef cows (16 Hereford and 34 Angus, 430 kg average body weight, aged 8 to 10 yr) were fed a basal diet containing 200 micrograms/g Al alone or supplemented with Al-citrate, citric acid, soil or soil plus citric acid for 56 d. Diets containing Al-citrate, soil and soil plus citric acid contained 1,730, 1,870 and 1,935 micrograms/g Al, dry-basis, respectively. Adding soil to the diet also increased Mg and Fe content of the diet. Aluminum values in ruminal contents of beef cows fed the basal alone or supplemented with citric acid, Al-citrate, soil or soil plus citric acid were 800, 990, 2,930, 3,410 and 2,910 micrograms/g, air-dry basis, respectively. Serum Mg and inorganic P declined (P less than .01) and urinary Ca concentration increased (P less than .01) for cows fed Al-citrate. By d 56, serum Mg was 1.5 and 2.2 mg/dl, and serum P was 3.8 and 6.8 mg/dl, for cows fed Al-citrate and basal diets, respectively. Calcium concentrations in urine were 281 and 11 micrograms/g for cows fed Al-citrate and basal diets, respectively. Citric acid, soil and soil plus citric acid had no detrimental effects on serum Mg and inorganic P, or urinary Ca concentration. By d 56, serum Ca was higher (P less than .06) in cows fed Al-citrate, compared with cows on the other four diets. Bone Ca, P, Zn and percent ash were not significantly affected by treatment but bone Mg tended to be slightly lower (P less than .07) for cows fed Al-citrate.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Reactive airways dysfunction syndrome in housewives due to a bleach-hydrochloric acid mixture.

    PubMed

    Gorguner, Metin; Aslan, Sahin; Inandi, Tacettin; Cakir, Zeynep

    2004-02-01

    The sudden onset of asthmalike symptoms and persistence of airway reactivity following an acute exposure to an irritant gas or vapor has been termed reactive airways dysfunction syndrome (RADS). A mixture of sodium hypochlorite (bleach, 40%) and hydrochloric acid (18%) is commonly used as a household cleaning solution in our region. From this mixture, chlorine gas is produced, which can cause airway damage and ensuing RADS. Here we describe findings of patients with RADS due to this cleaning mixture, and determine factors associated with a favorable outcome. Data were collected retrospectively on 55 symptomatic patients presenting to our emergency department after inhalation exposure to a mixture of bleach and hydrochloric acid. Symptoms, past medical and smoking history, details of the exposure, initial peak expiratory flow rate (PEFR) and oxygenation, and acute reversibility of airways obstruction were documented. All patients met previously defined criteria for the diagnosis of RADS, but did not undergo methacholine challenge testing and bronchoalveolar lavage or histopathologic study. Fifty patients were followed over the course of 3 mo. The majority of exposures (64%) occurred in the bathroom or kitchen. Only 21 of 55 (38%) patients showed an improvement in PEFR of 15% or greater following two beta(2)-agonist inhalation treatments. In follow-up, 48 patients (87%) improved clinically and functionally (FEV(1)). Seven patients (13%) deteriorated, with ARDS developing in two, one of whom died from respiratory failure. Advanced age, initial low PEFR, exposure in a small enclosed area, use immediately after mixing, and prolonged short- and long-term exposures were associated with a poorer prognosis. This descriptive study is the largest case series in the literature of RADS developing after exposure to a bleach-hydrochloric acid mixture. The optimum acute treatment and long-term outcomes for patients with RADS due to this combination still need to be determined.

  14. Regularities of extracting humic acids from soils using sodium pyrophosphate solutions

    NASA Astrophysics Data System (ADS)

    Bakina, L. G.; Drichko, V. F.; Orlova, N. E.

    2017-02-01

    Regularities of extracting humic acids from different soil types (soddy-podzolic soil, gray forest soil, and all chernozem subtypes) with sodium pyrophosphate solutions at different pH values (from 5 to 13) have been studied. It is found that, regardless of soil type, the process occurs in two stages through the dissociation of carboxylic groups and phenolic hydroxyls, each of which can be described by a logistic function. Parameters of the logistic equations approximating the extraction of humic acids from soils at different pH values are independent of the content and composition of humus in soils. Changes in the optical density of humic acids extracted from soils using sodium pyrophosphate solutions with different pH values are described in the first approximation by the Gaussian function. The optically densest humic acids are extracted using sodium pyrophosphate solutions at pH 10. Therefore, it is proposed to use an extract with pH 10 for the characterization of organic matter with the maximum possible degree of humification in the given soil.

  15. USE OF FATTY ACID STABLE CARBON ISOTOPE RATIO TO INDICATE MICROBIAL CARBON SOURCE IN TROPICAL SOILS

    EPA Science Inventory


    We use measurements of the concentration and stable carbon isotope ratio of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels, broad microbial community structure, and microbial carbon source. For studies of soil o...

  16. Emerging Technology Summary. ACID EXTRACTION TREATMENT SYSTEM FOR TREATMENT OF METAL CONTAMINATED SOILS

    EPA Science Inventory

    The Acid Extraction Treatment System (AETS) is intended to reduce the concentrations and/or teachability of heavy metals in contaminated soils so the soil can be returned to the site from which it originated. The objective of the project was to determine the effectiveness and com...

  17. Effect of tannic acid on the transcriptome of the soil bacterium Pseudomonas protegens Pf-5

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tannins are plant-produced organic compounds that are found in soils, are able to sequester iron, and have antimicrobial properties. We studied the effect of tannic acid on the molecular physiology of the soil-inhabiting biocontrol bacterium Pseudomonas protegens Pf-5 (formerly Pseudomonas fluoresce...

  18. FATTY ACID STABLE ISOTOPE INDICATORS OF MICROBIAL CARBON SOURCE IN TROPICAL SOILS

    EPA Science Inventory

    The soil microbial community plays an important role in tropical ecosystem functioning because of its importance in the soil organic matter (SOM) cycle. We have measured the stable carbon isotopic ratio (delta13C) of individual phospholipid fatty acids (PLFAs) in a variety of tr...

  19. Ameliorating soil acidity of tropical Oxisols by liming for sustainable crop production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The greatest potential for expanding the world’s agricultural frontier lies in the savanna regions of the tropics, which are dominated by Oxisols. Soil acidity and low native fertility, however, are major constraints for crop production on tropical Oxisols. Soil acidification is an ongoing natural p...

  20. Bioavailability of heavy metals in strongly acidic soils treated with exceptional quality biosolids

    SciTech Connect

    Basta, N.T.; Sloan, J.J.

    1999-03-01

    New federal regulations may increase application of exceptional quality (EQ) biosolids to acidic soils, and information on the effect of this practice on bioavailability of heavy metal is limited. The objective of this study was to compare bioavailability of heavy metal in soil treated with nonalkaline or alkaline EQ biosolids with limestone-treated soils. Three acidic soils (pH 3.7--4.3) were treated with three amounts of lime-stabilized biosolids (LS), anaerobic-digested biosolids (AN), or agricultural limestone (L), and incubated at 25 C. Soil solution Cd, Zn, and other chemical constituents were measured at 1, 30, 90, and 180 d incubation. Soil solution Cd and Zn were AN > LS {ge} L, C. Soil solution Cd and Zn increased with AN applied but decreased wit h LS applied. The high application of LS had soil solution Zn dramatically decreased at soil pH > 5.5 and >5.1, respectively. Soil solution Cd and Zn increases were AN > LS with incubation time. Biosolids treatments increased heavy metal in Ca(NO{sub 3}){sub 2} and NaOAc fractions. Except for Cd, most metal from biosolids were in EDTA and HNO{sub 3} fractions. Heavy metal bioavailability, measured using lettuce (Latuca sativa L.), was AN > LS {ge} L, C. Although state regulations prohibiting application of nonalkaline EQ biosolids to acidic soil is a prudent practice, application of EQ alkaline biosolids that achieves soil pH > 5 minimizes risk from soil solution Cd and Zn and plant uptake of heavy metal.

  1. Effects of citric acid and the siderophore desferrioxamine B (DFO-B) on the mobility of germanium and rare earth elements in soil and uptake in Phalaris arundinacea.

    PubMed

    Wiche, Oliver; Tischler, Dirk; Fauser, Carla; Lodemann, Jana; Heilmeier, Hermann

    2017-02-03

    Effects of citric acid and desferrioxamine B (DFO-B) on the availability of Ge and selected REEs (La, Nd, Gd, Er) to P. arundinacea were investigated. A soil dissolution experiment was conducted to elucidate the effect of citric acid and DFO-B at different concentrations (1 and 10 mmol l(-1) citric acid) on the release of Ge and REEs from soil. In a greenhouse plants of P. arundinacea were cultivated on soil and on sand cultures to investigate the effects of citric acid and DFO-B on the uptake of Ge and REEs by the plants. Addition of 10 mmol l(-1) citric acid significantly enhanced desorption of Ge and REEs from soil and uptake into soil-grown plants. Applying DFO-B enhanced the dissolution and the uptake of REEs, while no effect on Ge was observed. In sand cultures, presence of citric acid and DFO-B significantly decreased the uptake of Ge and REEs, indicating a discrimination of the formed complexes during uptake. This study clearly indicates that citric acid and the microbial siderophore DFO-B may enhance phytoextraction of Ge and REEs due to the formation of soluble complexes that increase the migration of elements in the rhizosphere.

  2. Effects of nitrogen fertilization on the acidity and salinity of greenhouse soils.

    PubMed

    Han, Jiangpei; Shi, Jiachun; Zeng, Lingzao; Xu, Jianming; Wu, Laosheng

    2015-02-01

    A greenhouse pot experiment was conducted to study the effects of conventional nitrogen fertilization on soil acidity and salinity. Three N rates (urea; N0, 0 kg N ha(-1); N1, 600 kg N ha(-1); and N2, 1,200 kg N ha(-1)) were applied in five soils with different greenhouse cultivation years to evaluate soil acidification and salinization rate induced by nitrogen fertilizer in lettuce production. Both soil acidity and salinity increased significantly as N input increased after one season, with pH decrease ranging from 0.45 to 1.06 units and electrolytic conductivity increase from 0.24 to 0.68 mS cm(-1). An estimated 0.92 mol H(+) was produced for 1 mol (NO2 (-) + NO3 (-))-N accumulation in soil. The proton loading from nitrification was 14.3-27.3 and 12.1-58.2 kmol H(+) ha(-1) in the center of Shandong Province under N1 and N2 rate, respectively. However, the proton loading from the uptake of excess bases by lettuces was only 0.3-4.5 % of that from nitrification. Moreover, the release of protons induced the direct release of base cations and accelerated soil salinization. The increase of soil acidity and salinity was attributed to the nitrification of excess N fertilizer. Compared to the proton loading by lettuce, nitrification contributed more to soil acidification in greenhouse soils.

  3. Composition of exchangeable bases and acidity in soils of the Crimean Mountains

    NASA Astrophysics Data System (ADS)

    Kostenko, I. V.

    2015-08-01

    Acid forest and mountainous meadow soils of the Crimean Mountains were studied. The amount of hydrogen and aluminum ions extracted from these soils depended on the pH of extracting agents. The maximum values of the soil acidity were obtained upon the extraction with a strongly alkaline solution of sodium acetate in 0.05 N NaOH. The application of this extractant made it possible to determine the total exchange acidity, the total amount of extractable aluminum, and the total cation exchange capacity of the soils after the extraction of all the acidic components from them. The values of these characteristics were significantly higher than the values of the potential acidity and cation exchange capacity obtained by the routine analytical methods. Hydrogen predominated among the acidic components of the exchange acidity in the humus horizons, whereas aluminum predominated among them in the underlying mineral horizons. Hydrothermic conditions and the character of vegetation and parent materials were the major factors affecting the relationships between bases and acidic components in the soil adsorption complex.

  4. Contributions of acid deposition and natural processes to cation leaching from forest soils: a review

    SciTech Connect

    Johnson, D.W.; Van Miegroet, H.; Cole, D.W.; Richter, D.D.

    1983-01-01

    Methods of quantifying the roles of atmospheric acid inputs and internal acid generation by carbonic, organic, and nitric acids are illustrated by reviewing data sets from several intensively studied sites in North America. Some of the sites (tropical, Costa Rica (La Selva); temperate deciduous, Tennessee (Walker Branch); and temperate coniferous, Washington (Thompson)) received acid precipitation whereas others (northern, southeast Alaska (Petersburg); and subalpine, Washington Cascades (Findley Lake)) did not. Natural leaching by carbonic acid dominated soil leaching in the tropical and temperate coniferous sites, nitric acid (caused by nitrification) dominated leaching in an N-fixing temperate deciduous site (red alder in Washington), and organic acids dominated surface soil leaching in the subalpine site and contributed to leaching of surface soils in several other sites. Only at the temperate deciduous sites in eastern Tennessee did atmospheric acid input play a major role in soil leaching. In no case, however, are the annual net losses of cations regarded as alarming as compared to soil exchangeable cation capital.

  5. Sequestration and bioavailability of perfluoroalkyl acids (PFAAs) in soils: Implications for their underestimated risk.

    PubMed

    Zhao, Lixia; Zhu, Lingyan; Zhao, Shuyan; Ma, Xinxin

    2016-12-01

    Different from typical hydrophobic organic contaminants (HOCs), perfluoroalkyl acids (PFAAs) are more soluble in water and less partitioned to soil than the HOCs. It remains unclear whether and to what extent PFAAs could be sequestrated in soil. In this study, sequential extraction of PFAAs in soil and bioaccumulation of PFAAs in earthworm were carried out to understand the sequestration and bioavailability of PFAAs in soils with different soil organic matter (SOM) and aged for different time periods (7 and 47d). Sequestration occurred in different degrees depending on the amount and compositions of SOM in soil, structural properties of PFAAs and aging time. Surprisingly, in one peat soil with high fraction of organic carbon (foc, 59%), the PFAAs were completely sequestrated in the soil. Aging might lead to further sequestration of PFAAs in soil with relatively lower foc. As a consequence of sequestration, the bioavailability of PFAAs in peat soils was reduced 3-10 times compared to that in the plain farmland soil. However, the sequestrated PFAAs were still bioaccumulative in earthworms to some extent. The results indicated that the risk of PFAAs in field soil with high content of SOM could be underestimated if only free PFAAs using mild solvent extraction were monitored.

  6. Dolomite application to acidic soils: a promising option for mitigating N2O emissions.

    PubMed

    Shaaban, Muhammad; Peng, Qi-An; Hu, Ronggui; Wu, Yupeng; Lin, Shan; Zhao, Jinsong

    2015-12-01

    Soil acidification is one of the main problems to crop productivity as well as a potent source of atmospheric nitrous oxide (N2O). Liming practice is usually performed for the amelioration of acidic soils, but the effects of dolomite application on N2O emissions from acidic soils are still not well understood. Therefore, a laboratory study was conducted to examine N2O emissions from an acidic soil following application of dolomite. Dolomite was applied to acidic soil in a factorial design under different levels of moisture and nitrogen (N) fertilizer. Treatments were as follows: dolomite was applied as 0, 1, and 2 g kg(-1) soil (named as CK, L, and H, respectively) under two levels of moisture [i.e., 55 and 90 % water-filled pore space (WFPS)]. All treatments of dolomite and moisture were further amended with 0 and 200 mg N kg(-1) soil as (NH4)2SO4. Soil properties such as soil pH, mineral N (NH4 (+)-N and NO3 (-)-N), microbial biomass carbon (MBC), dissolved organic carbon (DOC), and soil N2O emissions were analyzed throughout the study period. Application of N fertilizer rapidly increased soil N2O emissions and peaked at 0.59 μg N2O-N kg(-1) h(-1) under 90 % WFPS without dolomite application. The highest cumulative N2O flux was 246.32 μg N2O-N kg(-1) under 90 % WFPS without dolomite addition in fertilized soil. Addition of dolomite significantly (p ≤ 0.01) mitigated N2O emissions as soil pH increased, and H treatment was more effective for mitigating N2O emissions as compared to L treatment. The H treatment decreased the cumulative N2O emissions by up to 73 and 67 % under 55 and 90 % WFPS, respectively, in fertilized soil, and 60 and 68 % under 55 and 90 % WFPS, respectively, in unfertilized soil when compared to those without dolomite addition. Results demonstrated that application of dolomite to acidic soils is a promising option for mitigating N2O emissions.

  7. Acidification, heavy metal mobility and nutrient accumulation in the soil-plant system of a revegetated acid mine wasteland.

    PubMed

    Yang, Sheng-Xiang; Liao, Bin; Li, Jin-tian; Guo, Tao; Shu, Wen-Sheng

    2010-08-01

    A revegetation program was established at an extreme acidic and metal-toxic pyrite/copper mine wasteland in Guangdong Province, PR China using a combination of four native grass species and one non-native woody species. It was continued and monitored for 2 y. The emphasis was on acidification, metal mobility and nutrient accumulation in the soil-plant system. Our results showed the following: (i) the acid-forming potential of the mine soils decreased steadily with time, which might be due to plant root-induced changes inhibiting the oxidization of sulphide minerals; (ii) heavy metal extractability (diethylene-triamine-pentaacetic acid-extractable Pb and Zn) in the soils increased with time despite an increase in soil pH, which might be attributed to soil disturbance and plant rhizospheric processes, as well as a consequence of the enhanced metal accumulation in plants over time; and (iii) the vegetation cover increased rapidly with time, and plant development accelerated the accumulation of major nutrients (organic matter, total and ammonium-N, and available P and K). The 2-y field experiment demonstrates that direct seeding/planting of native plant species in combination with lime and manure amelioration is a practical approach to the initial establishment of a self-sustaining vegetation cover on this metalliferous and sulphide-bearing mine wasteland. However, heavy metal accumulation in the soil-plant system should be of great concern, and long-term monitoring of ecological risk must be an integral part of such a restoration scheme.

  8. Removal of heavy metals from contaminated soil by electrodialytic remediation enhanced with organic acids.

    PubMed

    Merdoud, Ouarda; Cameselle, Claudio; Boulakradeche, Mohamed Oualid; Akretche, Djamal Eddine

    2016-11-09

    The soil from an industrial area in Algeria was contaminated with Cr (8370 mg kg(-1)), Ni (1135 mg kg(-1)) and zinc (1200 mg kg(-1)). The electrodialytic remediation of this soil was studied using citric acid and EDTA as facilitating agents. 0.1 M citric acid or EDTA was added directly to the soil before it was introduced in an electrodialytic cell in an attempt to enhance the heavy metal solubility in the interstitial fluid. The more acidic pH in the soil when citric acid was used as the facilitating agent was not enough to mobilize and remove the metals from the soil. Only 7.2% of Ni and 6.7% of Zn were removed from the soil in the test with citric acid. The best results were found with EDTA, which was able to solubilize and complex Zn and Ni forming negatively charged complexes that were transported and accumulated in the anolyte. Complete removal was observed for Ni and Zn in the electrodialytic treatment with EDTA. Minor amounts of Cr were removed with both EDTA and citric acid.

  9. Determination of water-soluble forms of oxalic and formic acids in soils by ion chromatography

    NASA Astrophysics Data System (ADS)

    Karicheva, E.; Guseva, N.; Kambalina, M.

    2016-03-01

    Carboxylic acids (CA) play an important role in the chemical composition origin of soils and migration of elements. The content of these acids and their salts is one of the important characteristics for agrochemical, ecological, ameliorative and hygienic assessment of soils. The aim of the article is to determine water-soluble forms of same carboxylic acids — (oxalic and formic acids) in soils by ion chromatography with gradient elution. For the separation and determination of water-soluble carboxylic acids we used reagent-free gradient elution ion-exchange chromatography ICS-2000 (Dionex, USA), the model solutions of oxalate and formate ions, and leachates from soils of the Kola Peninsula. The optimal gradient program was established for separation and detection of oxalate and formate ions in water solutions by ion chromatography. A stability indicating method was developed for the simultaneous determination of water-soluble organic acids in soils. The method has shown high detection limits such as 0.03 mg/L for oxalate ion and 0.02 mg/L for formate ion. High signal reproducibility was achieved in wide range of intensities which correspond to the following ion concentrations: from 0.04 mg/g to 10 mg/L (formate), from 0.1 mg/g to 25 mg/L (oxalate). The concentration of formate and oxalate ions in soil samples is from 0.04 to 0.9 mg/L and 0.45 to 17 mg/L respectively.

  10. How do crop plants tolerate acid soils? Mechanisms of aluminum tolerance and phosphorous efficiency.

    PubMed

    Kochian, Leon V; Hoekenga, Owen A; Pineros, Miguel A

    2004-01-01

    Acid soils significantly limit crop production worldwide because approximately 50% of the world's potentially arable soils are acidic. Because acid soils are such an important constraint to agriculture, understanding the mechanisms and genes conferring tolerance to acid soil stress has been a focus of intense research interest over the past decade. The primary limitations on acid soils are toxic levels of aluminum (Al) and manganese (Mn), as well as suboptimal levels of phosphorous (P). This review examines our current understanding of the physiological, genetic, and molecular basis for crop Al tolerance, as well as reviews the emerging area of P efficiency, which involves the genetically based ability of some crop genotypes to tolerate P deficiency stress on acid soils. These are interesting times for this field because researchers are on the verge of identifying some of the genes that confer Al tolerance in crop plants; these discoveries will open up new avenues of molecular/physiological inquiry that should greatly advance our understanding of these tolerance mechanisms. Additionally, these breakthroughs will provide new molecular resources for improving crop Al tolerance via both molecular-assisted breeding and biotechnology.

  11. Simulated long-term changes in river discharge and soil moisture due to global warming

    USGS Publications Warehouse

    Manabe, S.; Milly, P.C.D.; Wetherald, R.

    2004-01-01

    By use of a coupled ocean atmosphere-land model, this study explores the changes of water availability, as measured by river discharge and soil moisture, that could occur by the middle of the 21st century in response to combined increases of greenhouse gases and sulphate aerosols based upon the "IS92a" scenario. In addition, it presents the simulated change in water availability that might be realized in a few centuries in response to a quadrupling of CO2 concentration in the atmosphere. Averaging the results over extended periods, the radiatively forced changes, which are very similar between the two sets of experiments, were successfully extracted. The analysis indicates that the discharges from Arctic rivers such as the Mackenzie and Ob' increase by up to 20% (of the pre-Industrial Period level) by the middle of the 21st century and by up to 40% or more in a few centuries. In the tropics, the discharges from the Amazonas and Ganga-Brahmaputra rivers increase substantially. However, the percentage changes in runoff from other tropical and many mid-latitude rivers are smaller, with both positive and negative signs. For soil moisture, the results of this study indicate reductions during much of the year in many semiarid regions of the world, such as the southwestern region of North America, the northeastern region of China, the Mediterranean coast of Europe, and the grasslands of Australia and Africa. As a percentage, the reduction is particularly large during the dry season. From middle to high latitudes of the Northern Hemisphere, soil moisture decreases in summer but increases in winter.

  12. Soil calcium status and the response of stream chemistry to changing acidic deposition rates

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.; Lovett, Gary M.; Murdoch, Peter S.; Burns, Douglas A.; Stoddard, J.L.; Baldigo, Barry P.; Porter, J.H.; Thompson, A.W.

    1999-01-01

    Despite a decreasing trend in acidic deposition rates over the past two to three decades, acidified surface waters in the northeastern United States have shown minimal changes. Depletion of soil Ca pools has been suggested as a cause, although changes in soil Ca pools have not been directly related to long-term records of stream chemistry. To investigate this problem, a comprehensive watershed study was conducted in the Neversink River Basin, in the Catskill Mountains of New York, during 1991-1996. Spatial variations of atmospheric deposition, soil chemistry, and stream chemistry were evaluated over an elevation range of 817-1234 m to determine whether these factors exhibited elevational patterns. An increase in atmospheric deposition of SO4 with increasing elevation corresponded with upslope decreases of exchangeable soil base concentrations and acid-neutralizing capacity of stream water. Exchangeable base concentrations in homogeneous soil incubated within the soil profile for one year also decreased with increasing elevation. An elevational gradient in precipitation was not observed, and effects of a temperature gradient on soil properties were not detected. Laboratory leaching experiments with soils from this watershed showed that (1) concentrations of Ca in leachate increased as the concentrations of acid anions in added solution increased, and (2) the slope of this relationship was positively correlated with base saturation. Field and laboratory soil analyses are consistent with the interpretation that decreasing trends in acid-neutralizing capacity in stream water in the Neversink Basin, dating back to 1984, are the result of decreases in soil base saturation caused by acidic deposition.

  13. Sorption of vapors of some organic liquids on soil humic acid and its relation to partitioning of organic compounds in soil organic matter

    USGS Publications Warehouse

    Chlou, G.T.; Kile, D.E.; Malcolm, R.L.

    1988-01-01

    Vapor sorption of water, ethanol, benzene, hexane, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,2-dibromoethane on (Sanhedron) soil humic acid has been determined at room temperature. Isotherms for all organic liquids are highly linear over a wide range of relative pressure (P/P??), characteristic of the partitioning (dissolution) of the organic compounds in soil humic acid. Polar liquids exhibit markedly greater sorption capacities on soil humic acid than relatively nonpolar liquids, in keeping with the polar nature of the soil humic acid as a partition medium. The limiting sorption (partition) capacities of relatively non-polar liquids are remarkably similar when expressed in terms of volumes per unit weight of soil humic acid. The soil humic acid is found to be about half as effective as soil organic matter in sorption of relatively nonpolar organic compounds. The nearly constant limiting sorption capacity for nonpolar organic liquids with soil humic acid on a volume-to-weight basis and its efficiency in sorption relative to soil organic matter provide a basis for predicting the approximate sorption (partition) coefficients of similar compounds in uptake by soil in aqueous systems.

  14. Quaternary herbicides retention by the amendment of acid soils with a bentonite-based waste from wineries.

    PubMed

    Pateiro-Moure, M; Nóvoa-Muñoz, J C; Arias-Estévez, M; López-Periago, E; Martínez-Carballo, E; Simal-Gándara, J

    2009-05-30

    The agronomic utility of a solid waste, waste bentonite (WB), from wine companies was assessed. In this sense, the natural characteristics of the waste were measured, followed by the monitoring of its effects on the adsorption/desorption behaviour of three quaternary herbicides in acid soils after the addition of increasing levels of waste. This was done with the intention of studying the effect of the added organic matter on their adsorption. The high content in C (294 g kg(-1)), N (28 g kg(-1)), P (584 mg kg(-1)) and K (108 g kg(-1)) of WB turned it into an appropriate amendment to increase soil fertility, solving at the same time its disposal. WB also reduced the potential Cu phytotoxicity due to a change in Cu distribution towards less soluble fractions. The adsorption of the herbicides paraquat, diquat and difenzoquat by acid soils amended with different ratios of WB was measured. In all cases, Langmuir equation was fitted to the data. Paraquat (PQ) and diquat (DQ) were adsorbed and retained more strongly than difenzoquat (DFQ) in the acid soil studied. However, the lowest retention of DFQ in an acid soil can be increased by amendment with organic matter through a solid waste from wineries, and it is enough for duplicate retention a dosage rate of 10t/ha. Anyway, detritivores ecology can still be affected. Detritivores are the organisms that consume organic material, and in doing so contribute to decomposition and the recycling of nutrients. The term can also be applied to certain bottom-feeders in wet environments, which play a crucial role in benthic ecosystems, forming essential food chains and participating in the nitrogen cycle.

  15. Extractive and oxidative removal of copper bound to humic acid in soil.

    PubMed

    Hwang, Bo-Ram; Kim, Eun-Jung; Yang, Jung-Seok; Baek, Kitae

    2015-04-01

    Copper (Cu) is often found strongly bound to natural organic matter (NOM) in soil through the formation of strong Cu-NOM complexes. Therefore, in order to successfully remediate Cu-contaminated soils, effective removal of Cu bound to soil organic matter should be considered. In this study, we investigated soil washing methods for Cu removal from a synthetic Cu-contaminated model silica soil coated with humic acid (HA) and from field contaminated soil. Various reagents were studied to extract Cu bound to NOM, which included oxidant (H2O2), base (NaOH), and chelating agents (citric acid and ethylenediaminetetraacetic acid (EDTA)). Among the wash reagents, EDTA extracted Cu most effectively since EDTA formed very strong complexes with Cu, and Cu-HA complexes were transformed into Cu-EDTA complexes. NaOH extracted slightly less Cu compared to EDTA. HA was effectively extracted from the model soil under strongly alkaline conditions with NaOH, which seemed to concurrently release Cu bound to HA. However, chemical oxidation with H2O2 was not effective at destroying Cu-HA complexes. Fourier transform infrared spectroscopy and elemental analysis revealed that chelating agents such as citrate and EDTA were adsorbed onto the model soil via possible complexation between HA and extraction agents. The extraction of Cu from a field contaminated soil sample was effective with chelating agents, while oxidative removal with H2O2 and extractive removal with NaOH separated negligible amounts of Cu from the soil. Based on these results, Cu bound to organic matter in soil could be effectively removed by chelating agents, although remnant agents may remain in the soil.

  16. Links between Ammonia Oxidizer Community Structure, Abundance, and Nitrification Potential in Acidic Soils ▿ †

    PubMed Central

    Yao, Huaiying; Gao, Yangmei; Nicol, Graeme W.; Campbell, Colin D.; Prosser, James I.; Zhang, Limei; Han, Wenyan; Singh, Brajesh K.

    2011-01-01

    Ammonia oxidation is the first and rate-limiting step of nitrification and is performed by both ammonia-oxidizing archaea (AOA) and bacteria (AOB). However, the environmental drivers controlling the abundance, composition, and activity of AOA and AOB communities are not well characterized, and the relative importance of these two groups in soil nitrification is still debated. Chinese tea orchard soils provide an excellent system for investigating the long-term effects of low pH and nitrogen fertilization strategies. AOA and AOB abundance and community composition were therefore investigated in tea soils and adjacent pine forest soils, using quantitative PCR (qPCR), terminal restriction fragment length polymorphism (T-RFLP) and sequence analysis of respective ammonia monooxygenase (amoA) genes. There was strong evidence that soil pH was an important factor controlling AOB but not AOA abundance, and the ratio of AOA to AOB amoA gene abundance increased with decreasing soil pH in the tea orchard soils. In contrast, T-RFLP analysis suggested that soil pH was a key explanatory variable for both AOA and AOB community structure, but a significant relationship between community abundance and nitrification potential was observed only for AOA. High potential nitrification rates indicated that nitrification was mainly driven by AOA in these acidic soils. Dominant AOA amoA sequences in the highly acidic tea soils were all placed within a specific clade, and one AOA genotype appears to be well adapted to growth in highly acidic soils. Specific AOA and AOB populations dominated in soils at particular pH values and N content, suggesting adaptation to specific niches. PMID:21571885

  17. Daily and seasonal changes in soil amino acid composition in a semiarid grassland exposed to elevated CO2 and warming

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil amino acids are often an important source of nitrogen (N) for plants, and anticipated global changes, including climate warming and rising atmospheric CO2 levels, have the potential to alter plant and microbial production and consumption of this N source in soils. We determined soil amino acid ...

  18. Sequential soil washing techniques using hydrochloric acid and sodium hydroxide for remediating arsenic-contaminated soils in abandoned iron-ore mines.

    PubMed

    Jang, Min; Hwang, Jung Sung; Choi, Sang Il

    2007-01-01

    Sequential washing techniques using single or dual agents [sodium hydroxide (NaOH) and hydrochloric acid (HCl) solutions] were applied to arsenic-contaminated soils in an abandoned iron-ore mine area. We investigated the best remediation strategies to maximize arsenic removal efficiency for both soils and arsenic-containing washing solution through conducting a series of batch experiments. Based on the results of a sequential extraction procedure, most arsenic prevails in Fe-As precipitates or coprecipitates, and iron exists mostly in the crystalline forms of iron oxide. Soil washing by use of a single agent was not effective in remediating arsenic-contaminated soils because arsenic extractions determined by the Korean standard test (KST) methods for washed soils were not lower than 6mg kg(-1) in all experimental conditions. The results of X-ray diffraction (XRD) indicated that iron-ore fines produced mobile colloids through coagulation and flocculation in water contacting the soils, containing dissolved arsenic and fine particles of ferric arsenate-coprecipitated silicate. The first washing step using 0.2M HCl was mostly effective in increasing the cationic hydrolysis of amorphous ferrihydrite, inducing high removal of arsenic. Thus, the removal step of arsenic-containing flocs can lower arsenic extractions (KST methods) of washed soils. Among several washing trials, alternative sequential washing using 0.2M HCl followed by 1M HCl (second step) and 1M NaOH solution (third step) showed reliable and lower values of arsenic extractions (KST methods) of washed soils. This washing method can satisfy the arsenic regulation of washed soil for reuse or safe disposal application. The kinetic data of washing tests revealed that dissolved arsenic was easily readsorbed into remaining soils at a low pH. This result might have occurred due to dominant species of positively charged crystalline iron oxides characterized through the sequential extraction procedure. However

  19. Enhanced Mineralization of [U-14C]2,4-Dichlorophenoxyacetic Acid in Soil from the Rhizosphere of Trifolium pratense

    PubMed Central

    Shaw, Liz J.; Burns, Richard G.

    2004-01-01

    Enhanced biodegradation in the rhizosphere has been reported for many organic xenobiotic compounds, although the mechanisms are not fully understood. The purpose of this study was to discover whether rhizosphere-enhanced biodegradation is due to selective enrichment of degraders through growth on compounds produced by rhizodeposition. We monitored the mineralization of [U-14C]2,4-dichlorophenoxyacetic acid (2,4-D) in rhizosphere soil with no history of herbicide application collected over a period of 0 to 116 days after sowing of Lolium perenne and Trifolium pratense. The relationships between the mineralization kinetics, the number of 2,4-D degraders, and the diversity of genes encoding 2,4-D/α-ketoglutarate dioxygenase (tfdA) were investigated. The rhizosphere effect on [14C]2,4-D mineralization (50 μg g−1) was shown to be plant species and plant age specific. In comparison with nonplanted soil, there were significant (P < 0.05) reductions in the lag phase and enhancements of the maximum mineralization rate for 25- and 60-day T. pratense soil but not for 116-day T. pratense rhizosphere soil or for L. perenne rhizosphere soil of any age. Numbers of 2,4-D degraders in planted and nonplanted soil were low (most probable number, <100 g−1) and were not related to plant species or age. Single-strand conformational polymorphism analysis showed that plant species had no impact on the diversity of α-Proteobacteria tfdA-like genes, although an impact of 2,4-D application was recorded. Our results indicate that enhanced mineralization in T. pratense rhizosphere soil is not due to enrichment of 2,4-D-degrading microorganisms by rhizodeposits. We suggest an alternative mechanism in which one or more components of the rhizodeposits induce the 2,4-D pathway. PMID:15294813

  20. Changes in acidity and metal geochemistry in soils, groundwater, drain and river water in the Lower Murray River after a severe drought.

    PubMed

    Mosley, Luke M; Fitzpatrick, Rob W; Palmer, David; Leyden, Emily; Shand, Paul

    2014-07-01

    Acid sulfate soils with sulfuric material (pH<4) can have significant impacts on surface water quality and aquatic ecosystems due to low pH and high soluble metal concentrations in runoff and drainage discharges. There has been limited research on the complex geochemical transformations that occur along flow pathways from the soil acidity source to receiving waters. We studied the integrated geochemistry of metals in acid sulfate soils with sulfuric material, groundwater, drain and river water in the Lower Murray River (South Australia) over a 2 year period. The oxidation of an estimated 3500 ha of acid sulfate soils with sulfidic material (pH>4) underlying this former floodplain occurred due to falling river and groundwater levels during the 2006-2010 extreme "millennium" drought. A low pH (<4.5) soil layer was found approximately 1-2.5m below ground level with substantial amounts (up to 0.2 mol H(+)/kg dry weight) of available/soluble acidity and retained acidity in the form of the Fe oxyhydroxy sulfate mineral jarosite. The jarosite appears to be dissolving over time and buffering the sub-surface soil layers at pH≈4. Metal (Fe, Al, Mn) and metalloid (As) lability was greatly increased in the acidic soil layer. Highly acidic and metal rich groundwater (median pH 4.3, Fe, Al, Mn of 0.04-0.52 mmol/L) was observed at the same depths as the acidic soil layers. Nearly all of the dissolved Fe in the groundwater was present as Fe(2+). In the drains, increases in pH and redox potential promoted formation of the Fe oxyhydroxysulfate mineral schwertmannite. This mineral precipitation transferred a portion of the dissolved acidity to the drain sediments. Upon discharge to, and dilution of, the acid drainage in the river, pH neutralisation and rapid oxidation, hydrolysis, and precipitation of solid Al and Fe phases occurred in a localised area. Acidity is persisting (>3 years) following a return to pre-drought water levels.

  1. Cultivation of an obligate acidophilic ammonia oxidizer from a nitrifying acid soil.

    PubMed

    Lehtovirta-Morley, Laura E; Stoecker, Kilian; Vilcinskas, Andreas; Prosser, James I; Nicol, Graeme W

    2011-09-20

    Nitrification is a fundamental component of the global nitrogen cycle and leads to significant fertilizer loss and atmospheric and groundwater pollution. Nitrification rates in acidic soils (pH < 5.5), which comprise 30% of the world's soils, equal or exceed those of neutral soils. Paradoxically, autotrophic ammonia oxidizing bacteria and archaea, which perform the first stage in nitrification, demonstrate little or no growth in suspended liquid culture below pH 6.5, at which ammonia availability is reduced by ionization. Here we report the discovery and cultivation of a chemolithotrophic, obligately acidophilic thaumarchaeal ammonia oxidizer, "Candidatus Nitrosotalea devanaterra," from an acidic agricultural soil. Phylogenetic analysis places the organism within a previously uncultivated thaumarchaeal lineage that has been observed in acidic soils. Growth of the organism is optimal in the pH range 4 to 5 and is restricted to the pH range 4 to 5.5, unlike all previously cultivated ammonia oxidizers. Growth of this organism and associated ammonia oxidation and autotrophy also occur during nitrification in soil at pH 4.5. The discovery of Nitrosotalea devanaterra provides a previously unsuspected explanation for high rates of nitrification in acidic soils, and confirms the vital role that thaumarchaea play in terrestrial nitrogen cycling. Growth at extremely low ammonia concentration (0.18 nM) also challenges accepted views on ammonia uptake and metabolism and indicates novel mechanisms for ammonia oxidation at low pH.

  2. Influence of various concentrations of selenic acid (IV) on the activity of soil enzymes.

    PubMed

    Nowak, J; Kaklewski, K; Klódka, D

    2002-05-27

    The aim of this experiment was the assessment of the influence of various concentrations of H2SeO3 (0.05, 0.5 and 5 mM) on the activity of soil enzymes over 112 days. The lab experiment was performed using soil samples (dust-silt black soil of 1.92% organic C content, pH 7.7), 60% maximal water capacity. The soil samples were treated with a selenic acid water solution at the concentrations mentioned above. As a reference, natural soil was used (without the selenic acid). The activity of the following enzymes was tested: beta-glucosidase, nitrate reductase, urease, dehydrogenase, acid and alkaline phosphatases. The soil was sampled at days 0, 1, 3, 7, 14, 28, 56 and 112. The results of the study have shown that the selenic acid had no effect on the activity of the beta-glucosidase in soil. In the course of the whole experiment, the applied selenic acid inhibited activity of the nitrate reductase up to 70% at 5 mM, and the activity of dehydrogenase was also decreased--by up to 85% at 5 mM, similarly to urease (with the exception of days 14 and 28), and acid phosphatase (until day 56). The activity of alkaline phosphatase was increased by the lowest concentration of selenic acid and decreased by the highest, which was found in the course of the whole experiment. The 5-mM concentration of selenic acid inhibited the activity of all the enzymes tested in this experiment.

  3. H-binding groups in lignite vs. soil humic acids: NICA-Donnan and spectroscopic parameters

    SciTech Connect

    Drosos, M.; Jerzykiewicz, M.; Deligiannakis, Y.

    2009-04-15

    A comparative study has been carried out for two sets of humic acids isolated from lignites and soils. H-binding data were analyzed using the NICA-Donnan model, for three Greek lignite humic acids (HA) plus IHSS Leonardite reference HA, and five Greek soil HAs plus a commercial peat HA. {sup 13}C-CP-MAS NMR and H-binding data provide quantitative estimates for functional groups, showing that lignite HAs of diverse origin have strikingly homogeneous properties, while the H-binding structural units of soil HAs are characterized by a large degree of variability. Consistent differences between soil HA vs. lignite HA are revealed at the level of functional groups' concentrations. In the pH range 4 to 10, soil HA showed a charge variation < 3 (equiv kg{sup -1}) while lignite HAs showed a higher charge variation > 3.5 (equiv kg{sup -1}).

  4. Changes of dominant periods of soils sites within Mexico City valley due to subsidence

    NASA Astrophysics Data System (ADS)

    Lermo, J.; Martinez, J.; Sanchez-Sesma, F. J.

    2013-05-01

    We report significant changes of the dominant periods in Mexico City soil sites within a time window of 20 years. Measurements were performed in a hundred points studied both in 1992 and 2012, including some well-known sites as SCT and CDAO. Data analysis suggests a linear relationship in terms of the initial period that describes this 20-years-variation. Changes of up to 0.9s within a zone traditionally considered as Lake (zone IIId) were detected. These period variations appear to be strongly correlated to regional subsidence. Besides, 810 new measurements of micro-tremors were performed at various sites. All this updates the information, reaching now 1300 data points that allowed the generation of a new seismic zonification for the Mexico City (Federal District) Building Code.

  5. What can legacy datasets tell us about soil quality trends? Soil acidity in Victoria

    NASA Astrophysics Data System (ADS)

    Marchant, B. P.; Crawford, D. M.; Robinson, N. J.

    2015-07-01

    Purpose-built soil monitoring networks have been established in many countries to identify where soil functionality is threatened and to target remediation initiatives. An alternative to purpose-built soil monitoring networks is to use legacy soils information. Such information yields almost instant assessments of soil change but the results should be interpreted with caution since the information was not collected with monitoring in mind. We assess the threat of soil acidification in Victoria using two legacy datasets: (i) the Victorian Soils Information System (VSIS) which is a repository of the results of soil analyses conducted for scientific purposes since the 1950s and (ii) a database of 75 000 routine soil test results requested by farmers between 1973 and 1993. We find that the VSIS measurements are clustered in space and time and are therefore suitable for local rather than broad-scale assessments of soil change. The farmers’ results have better spatial and temporal coverage and space-time models can be used to quantify the spatial and temporal trends in the pH measurements. However, careful validation of these findings is required since we do not completely understand how the measured paddocks were selected and we cannot be certain that sampling or laboratory protocols have not changed with time.

  6. Interactions of aluminum with forest soils and vegetation: Implications for acid deposition

    SciTech Connect

    Maynard, A.A.

    1989-01-01

    Recent evidence suggests that an important ecological consequence of acidic deposition is increased aluminum mobilization. There is concern that increased aluminum activity may produce toxic effects in forested ecosystems. My studies were concerned with the behavior of pedogenic and added aluminum in soils derived from chemically different parent material. Soil aluminum was related to the aluminum content of the vegetation found growing in the soils. In addition, aluminum levels of forest litter was compared to levels determined 40 years ago. Field, greenhouse, and laboratory investigations were conducted in which the effects of aluminum concentration on germination and early growth was determined. Soils were then used in greenhouse and laboratory studies to establish patterns of soil and plant aluminum behavior with implications to acid deposition. Results show that the amount of aluminum extracted was related to the pH value of the extracting solution and to the chemical characteristics of the soil. Some acid rain solutions extracted measurable amounts of aluminum from selected primary minerals. Germination and early growth of Pinus radiata was controlled by levels of aluminum in the soil or in solution. Field studies indicated that most forest species were sensitive to rising levels of aluminum in the soil. In general, ferns and fern allies were less sensitive to very high levels of aluminum in the soil, continuing to grow when more advanced dicots have disappeared. Aluminum tissue levels of all species were related to the concentration of aluminum in the soil as was the reappearance of species. Aluminum levels in leaf litter have risen at least 50% in the last 40 years. These values were consistent over 3 years. The implications to acid deposition were discussed.

  7. The effect of organic acid on the spectral-induced polarization response of soil

    NASA Astrophysics Data System (ADS)

    Schwartz, N.; Shalem, T.; Furman, A.

    2014-04-01

    In spectral-induced polarization (SIP) studies of sites contaminated by organic hydrocarbons, it was shown that biodegradation by-products in general, and organic acids in particular, significantly alter the SIP signature of the subsurface. Still a systematic study that considers the effect of organic acid on the physicochemical and electrical (SIP) properties of the soil is missing. The goal of this work is to relate between the effect of organic acid on the physicochemical properties of the soil, and the soil electrical properties. To do so, we measured the temporal changes of the soil chemical (ion content) and electrical (low-frequency SIP) properties in response to influx of organic acid at different concentrations, gradually altering the soil pH. Our results show that organic acid reduces the soil pH, enhances mineral weathering and consequently reduces both the in-phase and quadrature conductivity. At the pH range where mineral weathering is most significant (pH 6-4.5) a negative linear relation between the soil pH and the soil formation factor was found, suggesting that mineral weathering changes the pore space geometry and hence affecting the in-phase electrical conductivity. In addition, we attribute the reduction in the quadrature conductivity to an exchange process between the natural cation adsorbed on the mineral surface and hydronium, and to changes in the width of the pore bottleneck that results from the mineral weathering. Overall, our results allow a better understanding of the SIP signature of soil undergoing acidification process in general and as biodegradation process in particular.

  8. Dynamic functional characterization and phylogenetic changes due to Long Chain Fatty Acids pulses in biogas reactors

    PubMed Central

    Kougias, Panagiotis G.; Treu, Laura; Campanaro, Stefano; Zhu, Xinyu; Angelidaki, Irini

    2016-01-01

    The process stability of biogas plants is often deteriorated by the accumulation of Long Chain Fatty Acids (LCFA). The microbial community shifts due to LCFA disturbances have been poorly understood as the molecular techniques used were not able to identify the genome characteristics of uncultured microorganisms, and additionally, the presence of limited number of reference genomes in public databases prevented the comprehension of specific functional roles characterizing these microorganisms. The present study is the first research which deciphers by means of high throughput shotgun sequencing the dynamics of the microbial community during an inhibitory shock load induced by single pulses of unsaturated LCFA at two different concentrations (i.e. 2 g/L-reactor and 3 g/L-reactor). The metagenomic analysis showed that only the microbes associated with LCFA degradation could encode proteins related to “chemotaxis” and “flagellar assembly”, which promoted the ability to move towards the LCFA sources so as to degrade them. Moreover, the syntrophic interactions found between Syntrophomonas sp. together with Methanosarcina sp. were possibly assigned to the menaquinone-electron transfer. Finally, it was proven that a previously exposed to LCFA inoculum is more efficient in the degradation process of LCFA due to the specialization of the microbial consortium. PMID:27353502

  9. Dynamics and thermodynamics of toxic metals adsorption onto soil-extracted humic acid.

    PubMed

    Shaker, Medhat A; albishri, Hassan M

    2014-09-01

    Humic acids, HA represent a large portion of natural organic matter in soils, sediments and waters. They are environmentally important materials due to their extensive ubiquity and strong complexation ability, which can influence heavy metal removal and transportation in waters. The thermodynamics and kinetics of the adsorption of Cd(II) and Cr(VI) onto solid soil-derived HA have been investigated at optimum conditions of pH (5.5±0.1), metal concentration (10-100mmolL(-1)) and different temperatures (293-323K). The suitability of adsorption models such as Freundlich and Langmuir to equilibrium data was investigated. The adsorption was well described by Langmuir isotherm model in multi-detectable steps. Adsorption sites, i (i=A, B, C) with different capacities, νi are characterized. The stoichiometric site capacity is independent of temperature and equilibrium constant, Ki. Adsorption sites A and B are selectively occupied by Cr(VI) cations while sites A and C are selectively occupied by Cd(II) cations. The thermodynamic parameters of adsorption systems are correlated for each adsorption step. The adsorption is endothermic, spontaneous and favorable. Different kinetic models are applied and the adsorption of these heavy metals onto HA follows pseudo-second-order kinetics and equilibrium is achieved within 24h. The adsorption reaction is controlled by diffusion processes and the type of the adsorption is physical.

  10. [Nitrate nitrogen leaching and residue of humic acid fertilizer in field soil].

    PubMed

    Liu, Fang-chun; Xing, Shang-jun; Duan, Chun-hua; Du, Zhen-yu; Ma, Hai-lin; Ma, Bing-yao

    2010-07-01

    To elucidate the potential influence of humic acidfertilizer on groundwater and soil quality in clay soil (CS) and sandy soil (SS), nitrate nitrogen leaching and residue of different fertilizers in field soil were studied using a self-made leaching field device. Nitrate nitrogen concentration in leaching water of fertilizer treatments was 28.1%-222.2% higher than that of non-nitrogen treatment in different times, but humic acid fertilizer could prevent nitrate nitrogen leaching both in CS and SS, especially in CS. Nitrate nitrogen concentration of leaching water in CS was 41.2%-59.1% less than that in SS and the inhibiting effect in CS was greater than that in SS. Nitrate nitrogen could be accumulated in soil profile by fertilizer application. The residue of nitrate nitrogen retained in 0-40 cm soil layer of humic acid fertilizer treatment was 59.8% and 54.4% respectively, higher than that of urea and compound fertilizer treatments. Nitrate nitrogen amount of humic acid, urea and compound fertilizer treatments in SS was significantly less than that in CS, being 81.7%, 81.1% and 47.6% respectively. Compared with the conventional fertilizer, humic acid fertilizer treatment improved the contents of organic matter, available nitrogen, phosphorus, and potassium of upper layer soil as well as cation exchange capacity. Besides, total amount of water-soluble salts in humic acid fertilizer treatment was decreased by 24.8% and 22.5% in comparison to urea and compound fertilizer treatments in CS, respectively. In summary, the application of humic acid fertilizer could improve physical and chemical properties of upper layer soil and reduce the risk of potential pollution to groundwater.

  11. Assessment of bioavailable organic phosphorus in tropical forest soils by organic acid extraction and phosphatase hydrolysis.

    PubMed

    Darch, Tegan; Blackwell, Martin S A; Chadwick, David; Haygarth, Philip M; Hawkins, Jane M B; Turner, Benjamin L

    2016-12-15

    Soil organic phosphorus contributes to the nutrition of tropical trees, but is not accounted for in standard soil phosphorus tests. Plants and microbes can release organic anions to solubilize organic phosphorus from soil surfaces, and synthesize phosphatases to release inorganic phosphate from the solubilized compounds. We developed a procedure to estimate bioavailable organic phosphorus in tropical forest soils by simulating the secretion processes of organic acids and phosphatases. Five lowland tropical forest soils with contrasting properties (pH 4.4-6.1, total P 86-429 mg P kg(- 1)) were extracted with 2 mM citric acid (i.e., 10 μmol g(- 1), approximating rhizosphere concentrations) adjusted to soil pH in a 4:1 solution to soil ratio for 1 h. Three phosphatase enzymes were then added to the soil extract to determine the forms of hydrolysable organic phosphorus. Total phosphorus extracted by the procedure ranged between 3.22 and 8.06 mg P kg(- 1) (mean 5.55 ± 0.42 mg P kg(- 1)), of which on average three quarters was unreactive phosphorus (i.e., organic phosphorus plus inorganic polyphosphate). Of the enzyme-hydrolysable unreactive phosphorus, 28% was simple phosphomonoesters hydrolyzed by phosphomonoesterase from bovine intestinal mucosa, a further 18% was phosphodiesters hydrolyzed by a combination of nuclease from Penicillium citrinum and phosphomonoesterase, and the remaining 51% was hydrolyzed by a broad-spectrum phytase from wheat. We conclude that soil organic phosphorus can be solubilized and hydrolyzed by a combination of organic acids and phosphatase enzymes in lowland tropical forest soils, indicating that this pathway could make a significant contribution to biological phosphorus acquisition in tropical forests. Furthermore, we have developed a method that can be used to assess the bioavailability of this soil organic phosphorus.

  12. Determination of the D and L isomers of some protein amino acids present in soils

    NASA Technical Reports Server (NTRS)

    Pollock, G. E.; Cheng, C.-N.; Cronin, S. E.

    1977-01-01

    The D and L isomers of some protein amino acids present in soils were measured by using a gas chromatographic technique. The results of two processing procedures were compared to determine the better method. Results of the comparison indicated that the determination of D and L percentages requires amino acid purification if one is to obtain accurate data. It was found that very significant amounts of D-alanine, D-aspartic acid, and D-glutamic acid were present in the contemporary soils studied. Valine, isoleucine, leucine, proline, and phenylalanine generally contained only a trace to very small amounts of the D isomer. It is probable that the D-amino acids from the alanine, aspartic, and glutamic acids are contributed to the soil primarily via microorganisms. The finding of very significant quantities of some D-amino acids (about 5-16%) in present-day soils may alert some investigators of geological sediments to a possible problem in using amino acid racemization as an age-dating technique.

  13. Impact of mitigation strategies on acid sulfate soil chemistry and microbial community.

    PubMed

    Wu, Xiaofen; Sten, Pekka; Engblom, Sten; Nowak, Pawel; Österholm, Peter; Dopson, Mark

    2015-09-01

    Potential acid sulfate soils contain reduced iron sulfides that if oxidized, can cause significant environmental damage by releasing large amounts of acid and metals. This study examines metal and acid release as well as the microbial community capable of catalyzing metal sulfide oxidation after treating acid sulfate soil with calcium carbonate (CaCO3) or calcium hydroxide (Ca(OH)2). Leaching tests of acid sulfate soil samples were carried out in the laboratory. The pH of the leachate during the initial flushing with water lay between 3.8 and 4.4 suggesting that the jarosite/schwertmannite equilibrium controls the solution chemistry. However, the pH increased to circa 6 after treatment with CaCO3 suspension and circa 12 after introducing Ca(OH)2 solution. 16S rRNA gene sequences amplified from community DNA extracted from the untreated and both CaCO3 and Ca(OH)2 treated acid sulfate soils were most similar to bacteria (69.1% to 85.7%) and archaea (95.4% to 100%) previously identified from acid and metal contaminated environments. These species included a Thiomonas cuprina-like and an Acidocella-like bacteria as well as a Ferroplasma acidiphilum-like archeon. Although the CaCO3 and Ca(OH)2 treatments did not decrease the proportion of microorganisms capable of accelerating acid and metal release, the chemical effects of the treatments suggested their reduced activity.

  14. [Determination of 13C enrichment in soil amino acid enantiomers by gas chromatogram/mass spectrometry].

    PubMed

    He, Hong-Bo; Zhang, Wei; Ding, Xue-Li; Bai, Zhen; Liu, Ning; Zhang, Xu-Dong

    2008-06-01

    The transformation and renewal of amino acid enantiomers is of significance in indicating the turnover mechanism of soil organic matter. In this paper, a method of gas chromatogram/mass spectrometry combined with U-13 C-glucose incubation was developed to determine the 13C enrichment in soil amino acid enantiomers, which could effectively differentiate the original and the newly synthesized amino acids in soil matrix. The added U-13 C-glucose was utilized rapidly to structure the amino acid carbon skeleton, and the change of relative abundance of isotope ions could be determined by mass spectrometry. The direct incorporation of U-13 C glucose was estimated by the intensity increase of m/z (F + n) to F (F was parent fragment, and n was the carbon number in the fragment), while the total isotope incorporation from the added 13C could be calculated according to the abundance ratio increment summation from m/z (Fa + 1) through (Fa + T) (Fa was the fragment containing all original skeleton carbons, and T was the carbon number in the amino acid molecule). The 13C enrichment in the target compound was expressed as atom percentage excess (APE), and that of D-amino acid needed to be corrected by the coefficient of hydrolysis-induced racemization. The 13C enrichment reflected the carbon turnover velocity of individual amino acid enantiomers, and was powerful to investigate the dynamics of soil amino acids.

  15. Early indications of soil recovery from acidic deposition in U.S. red spruce forests

    USGS Publications Warehouse

    Lawrence, Gregory B.; Shortle, Walter C.; David, Mark B.; Smith, Kevin T.; Warby, Richard A.F.; Lapenis, Andrei G.

    2012-01-01

    Forty to fifty percent decreases in acidic deposition through the 1980s and 1990s led to partial recovery of acidified surface waters in the northeastern United States; however, the limited number of studies that have assessed soil change found increased soil acidification during this period. From existing data, it's not clear whether soils continued to worsen in the 1990s or if recovery had begun. To evaluate possible changes in soils through the 1990s, soils in six red spruce (Picea rubens Sarg.) stands in New York, Vermont, New Hampshire, and Maine, first sampled in 1992 to 1993, were resampled in 2003 to 2004. The Oa-horizon pH increased (P 42−, which decreased the mobility of Al throughout the upper soil profile. Results indicate a nascent recovery driven largely by vegetation processes.

  16. Remediation of heavy metal contaminated soil washing residues with amino polycarboxylic acids.

    PubMed

    Arwidsson, Zandra; Elgh-Dalgren, Kristin; von Kronhelm, Thomas; Sjöberg, Ragnar; Allard, Bert; van Hees, Patrick

    2010-01-15

    Removal of Cu, Pb, and Zn by the action of the two biodegradable chelating agents [S,S]-ethylenediaminedisuccinic acid (EDDS) and methylglycinediacetic acid (MGDA), as well as citric acid, was tested. Three soil samples, which had previously been treated by conventional soil washing (water), were utilized in the leaching tests. Experiments were performed in batches (0.3 kg-scale) and with a WTC-mixer system (Water Treatment Construction, 10 kg-scale). EDDS and MGDA were most often equally efficient in removing Cu, Pb, and Zn after 10-60 min. Nonetheless, after 10d, there were occasionally significant differences in extraction efficiencies. Extraction with citric acid was generally less efficient, however equal for Zn (mainly) after 10d. Metal removal was similar in batch and WTC-mixer systems, which indicates that a dynamic mixer system could be used in full-scale. Use of biodegradable amino polycarboxylic acids for metal removal, as a second step after soil washing, would release most remaining metals (Cu, Pb and Zn) from the present soils, however only after long leaching time. Thus, a full-scale procedure, based on enhanced metal leaching by amino polycarboxylic acids from soil of the present kind, would require a pre-leaching step lasting several days in order to be efficient.

  17. Remediation of Stratified Soil Acidity Through Surface Application of Lime in No-Till Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yield reduction and reduced crop vigor, resulting from soil acidification, are of increasing concern in eastern Washington and northern Idaho. In this region, soil pH has been decreasing at an accelerated rate, primarily due to the long-term use of ammonium based fertilizers. In no-till systems, the...

  18. Understanding the mechanism behind the nitrous acid (HONO) emissions from the northern soils

    NASA Astrophysics Data System (ADS)

    Bhattarai, Hem Raj; Siljanen, Henri MP; Biasi, Christina; Maljanen, Marja

    2016-04-01

    The interest of the flux of nitrous acid (HONO) from soils has recently increased. HONO is an important source of the oxidant OH- radical in the troposphere and thus results a reduction of the greenhouse gas methane (CH4) in the atmosphere. Soils have been recently found to be potential sources of HONO as these emissions are linked to other nitrogen cycle processes, especially presence of nitrite in soils. Ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) have been suggested as possible yet substantial sources of HONO. Along with soil pH, other physical properties such as C:N, nitrogen availability, soil moisture and temperature may effect HONO emissions. Our preliminary results demonstrate that drained acidic peatlands with a low C:N produces higher NO, N2O and HONO emissions compared to those in pristine peatlands and upland forest soils. This study will identify the hotspots and the process involved in HONO emissions in northern ecosystems. Along with HONO, we will examine the emissions of NO and N2O to quantify the related N-gases emitted. These results will add a new piece of information in our knowledge of the nitrogen cycle. Soil samples will be collected from several boreal and arctic sites in Finland, Sweden and Russia. In the laboratory, soil samples will be manipulated based on previously described soil physical properties. This will be followed by labelling experiment coupled with selective nitrification inhibitor experiment in the soils. Our first hypothesis is that northern ecosystems are sources of HONO. Second, is that the soil properties (C:N ratio, moisture, N-availability, pH) regulate the magnitude of HONO emissions from northern soils. Third is that the first step of nitrification (ammonium oxidation) is the main pathway to produce HONO. This study will show that the northern ecosystems could be sources of HONO and therefore increasing the oxidizing capacity of the lower atmosphere.

  19. Accumulation of different sulfur fractions in Chinese forest soil under acid deposition.

    PubMed

    Wang, Zhanyi; Zhang, Xiaoshan; Zhang, Yi; Wang, Zhangwei; Mulder, Jan

    2011-09-01

    Atmogenic sulfur (S) deposition loading by acid rain is one of the biggest environmental problems in China. It is important to know the accumulated S stored in soil, because eventually the size (and also the "desorption" rate) determines how rapidly the soil water pH responds to decrease in S deposition. The S fractions and the ratio of total carbon/total sulfur (C/S) of forest soil in 9 catchments were investigated by comparing soils at the rural and urban sites in China. The S fractions included water-soluble sulfate-S (SO(4)-S), adsorbed SO(4)-S, insoluble SO(4)-S and organic S. The ratio of C/S in soil at the rural site was significantly (p < 0.05) greater than that at the urban site. C/S of soil in the A horizon was significantly (p < 0.05) and negatively correlated with the wet S-deposition rate. The ratio of C/S presents a better indicator for atmogenic S loading. Organic S was the dominant form in soils at rural sites; contributing more than 69% of the total S in the uppermost 30 cm soil. Organic S and adsorbed SO(4)-S were the main forms of S in soil at urban sites. High contents of water-soluble SO(4)-S and adsorbed SO(4)-S were found in uppermost 30 cm soils at urban sites but not at rural sites. Decades of acid rain have caused accumulation of inorganic SO(4)-S in Chinese forest soil especially at the urban sites. The soil at urban sites had been firstly acidified, and the impacts on the forest ecosystem in these areas should be noticed.

  20. Ecosystem-specific selection of microbial ammonia oxidizers in an acid soil

    NASA Astrophysics Data System (ADS)

    Saiful Alam, M.; Ren, G.; Lu, L.; Zheng, Y.; Peng, X.; Jia, Z.

    2013-01-01

    The function of ammonia-oxidizing archaea (AOA) and bacteria (AOB) depends on the availability of ammonia substrate and the supply of oxygen. The interactions and evolutions of AOA and AOB communities along ecological gradients of substrate availability in complex environment have been much debated, but rarely tested. In this study, two ecosystems of maize and rice crops under different fertilization regimes were selected to investigate the community diversification of soil AOA and AOB in response to long-term field fertilization and flooding management in an acid soil. Real-time quantitative PCR of amoA genes demonstrated that the abundance of AOA was significantly stimulated after conversion of upland to paddy soils, while slight decline of AOB populations was observed. DGGE fingerprints of amoA genes further revealed remarkable changes in community compositions of AOA in paddy soil when compared to upland soil. Sequencing analysis revealed that upland soil was dominated by AOA within the soil group 1.1b lineage, while the marine group 1.1a lineage predominated AOA communities in paddy soils. Irrespective of upland and paddy soils, long-term field fertilizations led to higher abundance of amoA genes of AOA and AOB than control treatment that received no fertilization, whereas archaeal amoA gene abundances outnumbered their bacterial counterpart in all samples. Phylogenetic analyses of amoA genes showed that Nitrosospira cluster 3-like AOB dominated bacterial ammonia oxidizers in both paddy and upland soils, regardless of fertilization treatments. The results of this study suggest that the marine group 1.1a AOA could be better adapted to low-oxygen environment than AOA ecotypes of the soil group 1.1b lineage, and implicate that long-term flooding as the dominant selective force driving the community diversification of AOA populations in the acid soil tested.

  1. Manganese Toxicity in Sugarcane Plantlets Grown on Acidic Soils of Southern China

    PubMed Central

    Huang, Yu Lan; Yang, Shu; Long, Guang Xia; Zhao, Zun Kang; Li, Xiao Feng; Gu, Ming Hua

    2016-01-01

    Ratoon sugarcane plantlets in southern China have suffered a serious chlorosis problem in recent years. To reveal the causes of chlorosis, plant nutrition in chlorotic sugarcane plantlets and the role of manganese (Mn) in this condition were investigated. The study results showed that the pH of soils growing chlorotic plantlets ranged from 3.74 to 4.84. The symptoms of chlorosis were similar to those of iron (Fe) deficiency while the chlorotic and non-chlorotic plantlets contained similar amount of Fe. Chlorotic plantlets had 6.4-times more Mn in their leaf tissues compared to the control plants. There was a significantly positive correlation between Mn concentration in the leaves and the exchangeable Mn concentration in the soils. Moreover, leaf Mn concentration was related to both seasonal changes in leaf chlorophyll concentration and to the occurrence of chlorosis. Basal stalks of mature sugarcanes contained up to 564.36 mg·kg-1 DW Mn. Excess Mn in the parent stalks resulted in a depress of chlorophyll concentration in the leaves of sugarcanes as indicated by lower chlorophyll concentration in the leaves of plantlets emerged from basal stalks. Ratoon sugarcane plantlets were susceptible to chlorosis due to high Mn accumulation in their leaves (456.90–1626.95 mg·kg-1 DW), while in planted canes chlorosis did not occur because of low Mn accumulation (94.64–313.41mg·kg-1 DW). On the other hand, active Fe content in chlorotic plantlets (3.39 mg kg-1 FW) was only equivalent to 28.2% of the concentration found in the control. These results indicate that chlorosis in ratoon sugarcane plantlets results from excessive Mn accumulated in parent stalks of planted cane sugarcanes grown on excessive Mn acidic soils, while active Fe deficiency in plantlets may play a secondary role in the chlorosis. PMID:27023702

  2. Biochar increases arsenic release from an anaerobic paddy soil due to enhanced microbial reduction of iron and arsenic.

    PubMed

    Wang, Ning; Xue, Xi-Mei; Juhasz, Albert L; Chang, Zhi-Zhou; Li, Hong-Bo

    2017-01-01

    Previous studies have shown that biochar enhances microbial reduction of iron (Fe) oxyhydroxide under anaerobic incubation. However, there is a lack of data on its influence on arsenic (As) release from As-contaminated paddy soils. In this study, paddy soil slurries (120 mg As kg(-1)) were incubated under anaerobic conditions for 60 days with and without the addition of biochar (3%, w/w) prepared from rice straw at 500 °C. Arsenic release, Fe reduction, and As fractionation were determined at 1, 10, 20, 30, and 60 d, while Illumina sequencing and real-time PCR were used to characterize changes in soil microbial community structure and As transformation function genes. During the first month of incubation, As released into soil solution increased sharply from 27.9 and 55.9 to 486 and 630 μg kg(-1) in unamended and biochar amended slurries, with inorganic trivalent As (As(III)) being the dominant specie (52.7-91.0% of total As). Compared to unamended slurries, biochar addition increased As and ferrous ion (Fe(2+)) concentrations in soil solution but decreased soil As concentration in the amorphous Fe/Al oxide fraction (F3). Difference in released As between biochar and unamended treatments (ΔAs) increased with incubation time, showing strong linear relationships (R(2) = 0.23-0.33) with ΔFe(2+) and ΔF3, confirming increased As release due to enhanced Fe reduction. Biochar addition increased the abundance of Fe reducing bacteria such as Clostridum (27.3% vs. 22.7%), Bacillus (3.34% vs. 2.39%), and Caloramator (4.46% vs. 3.88%). In addition, copy numbers in biochar amended slurries of respiratory As reducing (arrA) and detoxifying reducing genes (arsC) increased 19.0 and 1.70 fold, suggesting microbial reduction of pentavalent As (As(V)) adsorbed on Fe oxides to As(III), further contributing to increased As release.

  3. Arsenic biogeochemistry and human health risk assessment in organo-arsenical pesticide-applied acidic and alkaline soils: an incubation study.

    PubMed

    Datta, Rupali; Sarkar, Dibyendu; Sharma, Saurabh; Sand, Kumarswamy

    2006-12-15

    Organo-arsenical compounds are considered non-carcinogenic, and hence, are still allowed by the regulatory agencies for use in agriculture as pesticides. Due to rapid encroachment of suburban areas into former agricultural lands, the potential for human exposure to soil-arsenic has increased tremendously in recent years. However, insufficient data is available on the stability of organo-arsenicals in soils; as to whether they remain in an organic form, or are converted over time to potentially carcinogenic inorganic forms. A static incubation study was conducted to estimate soil speciation and in-vitro bioavailability (i.e., bioaccessibility) of arsenic as a function of soil properties. Two chemically variant soil types were chosen, based on their potential differences with respect to arsenic reactivity: an acid sand with minimal arsenic retention capacity and an alkaline clay loam with relatively high concentrations of Fe/Al and Ca/Mg. The soils were amended with dimethylarsenic acid (DMA) at three rates, 45, 225 and 450 mg/kg, and incubated for 1 year. A sequential extraction scheme was employed to identify the geochemical forms of arsenic in soils, which were correlated with the in-vitro bioavailable fractions of arsenic. Human health risk calculated in terms of excess cancer risk (ECR) showed that risk assessment based on bioaccessible arsenic concentrations instead of the traditional total soil arsenic is a more realistic approach. Results showed that soil properties (such as pH, Fe/Al content and soil texture) of the two soils dictated the geochemical speciation, and hence, bioaccessibility of arsenic from DMA, indicating that the use of organic arsenicals as pesticides in mineral soils may not be a safe practice from a human health risk perspective.

  4. Rhizosphere bacterial carbon turnover is higher in nucleic acids than membrane lipids: implications for understanding soil carbon cycling

    PubMed Central

    Malik, Ashish A.; Dannert, Helena; Griffiths, Robert I.; Thomson, Bruce C.; Gleixner, Gerd

    2015-01-01

    Using a pulse chase 13CO2 plant labeling experiment we compared the flow of plant carbon into macromolecular fractions of rhizosphere soil microorganisms. Time dependent 13C dilution patterns in microbial cellular fractions were used to calculate their turnover time. The turnover times of microbial biomolecules were found to vary: microbial RNA (19 h) and DNA (30 h) turned over fastest followed by chloroform fumigation extraction-derived soluble cell lysis products (14 days), while phospholipid fatty acids (PLFAs) had the slowest turnover (42 days). PLFA/NLFA 13C analyses suggest that both mutualistic arbuscular mycorrhizal and saprophytic fungi are dominant in initial plant carbon uptake. In contrast, high initial 13C enrichment in RNA hints at bacterial importance in initial C uptake due to the dominance of bacterial derived RNA in total extracts of soil RNA. To explain this discrepancy, we observed low renewal rate of bacterial lipids, which may therefore bias lipid fatty acid based interpretations of the role of bacteria in soil microbial food webs. Based on our findings, we question current assumptions regarding plant-microbe carbon flux and suggest that the rhizosphere bacterial contribution to plant assimilate uptake could be higher. This highlights the need for more detailed quantitative investigations with nucleic acid biomarkers to further validate these findings. PMID:25914679

  5. Carbon stabilization and microbial growth in acidic mine soils after addition of different amendments for soil reclamation

    NASA Astrophysics Data System (ADS)

    Zornoza, Raúl; Acosta, Jose; Ángeles Muñoz, María; Martínez-Martínez, Silvia; Faz, Ángel; Bååth, Erland

    2016-04-01

    The extreme soil conditions in metalliferous mine soils have a negative influence on soil biological activity and therefore on soil carbon estabilization. Therefore, amendments are used to increase organic carbon content and activate microbial communities. In order to elucidate some of the factors controlling soil organic carbon stabilization in reclaimed acidic mine soils and its interrelationship with microbial growth and community structure, we performed an incubation experiment with four amendments: pig slurry (PS), pig manure (PM) and biochar (BC), applied with and without marble waste (MW; CaCO3). Results showed that PM and BC (alone or together with MW) contributed to an important increment in recalcitrant organic C, C/N ratio and aggregate stability. Bacterial and fungal growths were highly dependent on pH and labile organic C. PS supported the highest microbial growth; applied alone it stimulated fungal growth, and applied with MW it stimulated bacterial growth. BC promoted the lowest microbial growth, especially for fungi, with no significant increase in fungal biomass. MW+BC increased bacterial growth up to values similar to PM and MW+PM, suggesting that part of the biochar was degraded, at least in short-term mainly by bacteria rather than fungi. PM, MW+PS and MW+PM supported the highest microbial biomass and a similar community structure, related with the presence of high organic C and high pH, with immobilization of metals and increased soil quality. BC contributed to improved soil structure, increased recalcitrant organic C, and decreased metal mobility, with low stimulation of microbial growth.

  6. Red spruce germination and growth in soil-mediated regeneration microcosms under acid precipitation

    SciTech Connect

    Ho, M.

    1992-01-01

    In the past three decades, atmospheric pollution has caused substantial problems for the environment as well as for many biological processes. The objective of this study focuses on red spruce (Picea ruben Sarg.) regeneration potential and chemical change within the soil-water-plant continuum following simulated acid rain treatments. Inceptisols from three forests at 1735, 1920, and 2015 m at Mt. Mitchell, North Carolina had lower pH, bulk density, and higher organic matter, and base cations as altitude increased. Red spruce seeds were collected from two nearby standing trees at the 1735 m site. A strip-split-split plot experiment was constructed using soils from the two lower elevations, which support natural red spruce stands. Besides a control (pH 5.6, NO[sub 3]:SO[sub 4] ratio 0.10), eight treatments corresponding to two pHs (3.5 and 4.2) with four NO[sub 3]:SO[sub 4] ratios (0.20, 0.33, 0.40, and 0.67) each were used. Seedling emergence and growth, chemistry of soil. Soil leachate, and plant tissue were analyzed to test soil differences and treatment effects of acidity, nitrate, and sulfate. Temporal patterns of germination respond more to soil than to rain chemistry, but significant interactions were found. Besides higher survival, faster germinating seedlings in the 1735 m soil also produced more complex root system and more biomass. Lower root-to-shoot ratios at more acidic treatments suggest a negative effect of acidity on root growth. Canonical discriminant analysis revealed that factors controlling overall soil chemistry were dominated by soil origin, then by rain pH.

  7. Positive trends in organic carbon storage in Swedish agricultural soils due to unexpected socio-economic drivers

    NASA Astrophysics Data System (ADS)

    Poeplau, C.; Bolinder, M. A.; Eriksson, J.; Lundblad, M.; Kätterer, T.

    2015-06-01

    Soil organic carbon (SOC) plays a crucial role in the global carbon cycle as a potential sink or source. Land management influences SOC storage, so the European Parliament decided in 2013 that changes in carbon stocks within a certain land use type, including arable land, must be reported by all member countries in their national inventory reports for greenhouse gas emissions. Here we show the temporal dynamics of SOC during the past 2 decades in Swedish agricultural soils, based on soil inventories conducted in 1988-1997 (Inventory I), 2001-2007 (Inventory II) and from 2010 onwards (Inventory III), and link SOC changes with trends in agricultural management. From Inventory I to Inventory II, SOC increased in 16 out of 21 Swedish counties, while from Inventory I to Inventory III it increased in 18 out of 21 counties. Mean topsoil (0-20 cm) SOC concentration for the entire country increased from 2.48 to 2.67% C (a relative increase of 7.7%, or 0.38% yr-1) over the whole period. We attributed this to a substantial increase in ley as a proportion of total agricultural area in all counties. The horse population in Sweden has more than doubled since 1981 and was identified as the main driver for this management change (R2 = 0.72). Due to subsidies introduced in the early 1990s, the area of long-term set-aside (mostly old leys) also contributed to the increase in area of ley. The carbon sink function of Swedish agricultural soils demonstrated in this study differs from trends found in neighbouring countries. This indicates that country-specific or local socio-economic drivers for land management must be accounted for in larger-scale predictions.

  8. Positive trends in organic carbon storage in Swedish agricultural soils due to unexpected socio-economic drivers

    NASA Astrophysics Data System (ADS)

    Poeplau, C.; Bolinder, M. A.; Eriksson, J.; Lundblad, M.; Kätterer, T.

    2015-03-01

    Soil organic carbon (SOC) plays a crucial role in the global carbon cycle as a potential sink or source. Land management influences SOC storage, so the European Parliament decided in 2013 that changes in carbon stocks within a certain land use type, including arable land, must be reported by all member countries in their national inventory reports for greenhouse gas emissions. Here we show the temporal dynamics of SOC during the past two decades in Swedish agricultural soils, based on soil inventories conducted in 1988-1997 (Inventory I), 2001-2007 (Inventory II) and from 2010 onwards (Inventory III), and link SOC changes with trends in agricultural management. From Inventory I to Inventory II, SOC increased in 16 out of 21 Swedish counties, while from Inventory I to Inventory III it increased in 18 out of 21 counties. Mean topsoil (0-20 cm) SOC concentration for the entire country increased from 2.48 to 2.67% C (a relative increase of 7.7%, or 0.38% yr-1) over the whole period. We attributed this to a substantial increase in ley as a proportion of total agricultural area in all counties. The horse population in Sweden has more than doubled since 1981 and was identified as the main driver for this management change (R2 = 0.72). Due to subsidies introduced in the early 1990s, the area of long-term set-aside (mostly old leys) also contributed to the increase in area of ley. The carbon sink function of Swedish agricultural soils demonstrated in this study differs from trends found in neighbouring countries. This indicates that country-specific or local socio-economic drivers for land management must be accounted for in larger-scale predictions.

  9. Quality improvement of acidic soils by biochar derived from renewable materials.

    PubMed

    Moon, Deok Hyun; Hwang, Inseong; Chang, Yoon-Young; Koutsospyros, Agamemnon; Cheong, Kyung Hoon; Ji, Won Hyun; Park, Jeong-Hun

    2017-02-01

    Biochar derived from waste plant materials and agricultural residues was used to improve the quality of an acidic soil. The acidic soil was treated for 1 month with both soy bean stover-derived biochar and oak-derived biochar in the range of 1 to 5 wt% for pH improvement and exchangeable cation enhancement. Following 1 month of treatment, the soil pH was monitored and exchangeable cations were measured. Moreover, a maize growth experiment was performed for 14 days with selected treated soil samples to confirm the effectiveness of the treatment. The results showed that the pH of the treated acidic soil increased by more than 2 units, and the exchangeable cation values were greatly enhanced upon treatment with 5 wt% of both biochars, after 1 month of curing. Maize growth was superior in the 3 wt% biochar-treated samples compared to the control sample. The presented results demonstrate the effective use of biochar derived from renewable materials such as waste plant materials and agricultural residues for quality improvement of acidic soils.

  10. Long-term changes in soil erosion due to forest fires. A rainfall simulation approach in Eastern Spain

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Keesstra, Saskia; Pereira, Paulo; Matrix-Solera, Jorge; Giménez-Morera, Antonio; Úbeda, Xavier; Francos, Marcos; Alcañiz, Meritxell; Jordán, Antonio

    2016-04-01

    Soils are affected by the impacts of wildfires (Dlapa et al., 2013; Pereira et al., 2014; Tsibart et al., 2014; Dlapa et al., 2015, Hedo et al., 2015; Tessler et al., 2015). Soil erosion rates are highly affected by forest fires due to the removal of the above ground vegetation, the heat impact on the soil, the reduction of the organic matter, the ash cover, and the changes introduced by the rainfall on the soil surface (Lasanta and Cerdà, 2005; Mataix-Solera et al., 2011; Novara et al., 2011; Novara et al., 2013; Keesstra et al., 2014; Hedo et al., 2015; Pereira, 2015). Most of the research carried out on forest fire affected land paid attention to the "window of disturbance", which is the period that the soil losses are higher than before the forest fire and that last for few years (Cerdà, 1998a; Cerdà 1998b, Pérez-Cabello et al., 2011; Bodí et al., 2011; Bodí et al., 2012; Pereira et al., 2013: Pereira et al., 2015). However, the spatial and temporal variability of soil erosion is very high as a result of the uneven temporal and spatial distribution of the rainfall (Novara et al., 2011; Bisantino et al., 2015; Gessesse et al., 2015; Ochoa et al., 2015), and the window of disturbance cannot be easily found under natural rainfall. In order to understand the evolution of soil erosion after forest fires it is necessary to monitor fire affected sites over a long period of time, which will enable the assessment of the period affected by the window of disturbance (see Cerdà and Doerr, 2005). However, it is also possible to do measurements and experiments in areas with a different fire history. This will give us information about the temporal changes in soil erosion after forest fire. To reduce the spatial variability of rainfall we can use simulated rainfall that can be applied at multiple site with the same rainfall intensity and duration. For this purpose rainfall simulation can be of great help, in the laboratory (Moreno et al., 2014; Sadegui et al., 2015

  11. Effect of humic acid on the photolysis of the pesticide atrazine in a surfactant-aided soil-washing system in acidic condition.

    PubMed

    Chan, K H; Chu, W

    2005-05-01

    The photolytic destruction of Atrazine (ATZ) following a surfactant-aided soil-washing process was investigated in the presence of humic acid (HA). A non-ionic surfactant, Brij 35, was found to be a good solving agent, extracting ATZ without causing any retardation effect on the photolysis process. However, the HA that was co-extracted from the surfactant-aided soil-washing system was found to be capable of improving the photolysis of ATZ at low concentrations, while quenching the photodegradation of ATZ at higher concentrations. By considering the light attenuation effect due to surfactant and HA, the quantum yields of the system with respect to the proposed reaction mechanisms of the associated excited states of ATZ were investigated and modeled. The relative kinetic rates of the dominant reaction mechanisms (i.e., deactivation of triplet, direct photolysis of triplet, product formation, and quenching of triplet) were then compared.

  12. Effective treatment of PAH contaminated Superfund site soil with the peroxy-acid process.

    PubMed

    Scott Alderman, N; N'Guessan, Adeola L; Nyman, Marianne C

    2007-07-31

    Peroxy-organic acids are formed by the chemical reaction between organic acids and hydrogen peroxide. The peroxy-acid process was applied to two Superfund site soils provided by the U.S. Environmental Protection Agency (EPA). Initial small-scale experiments applied ratios of 3:5:7 (v/v/v) or 3:3:9 (v/v/v) hydrogen peroxide:acetic acid:deionized (DI) water solution to 5g of Superfund site soil. The experiment using 3:5:7 (v/v/v) ratio resulted in an almost complete degradation of the 14 EPA regulated polycyclic aromatic hydrocarbons (PAHs) in Bedford LT soil during a 24-h reaction period, while the 3:3:9 (v/v/v) ratio resulted in no applicable degradation in Bedford LT lot 10 soil over the same reaction period. Specific Superfund site soil characteristics (e.g., pH, total organic carbon content and particle size distribution) were found to play an important role in the availability of the PAHs and the efficiency of the transformation during the peroxy-acid process. A scaled-up experiment followed treating 150g of Bedford LT lot 10 soil with and without mixing. The scaled-up processes applied a 3:3:9 (v/v/v) solution resulting in significant decrease in PAH contamination. These findings demonstrate the peroxy-acid process as a viable option for the treatment of PAH contaminated soils. Further work is necessary in order to elucidate the mechanisms of this process.

  13. Influence of soil tillage and erosion on the dispersion of glyphosate and aminomethylphosphonic acid in agricultural soils

    NASA Astrophysics Data System (ADS)

    Todorovic, Gorana Rampazzo; Rampazzo, Nicola; Mentler, Axel; Blum, Winfried E. H.; Eder, Alexander; Strauss, Peter

    2014-03-01

    Erosion processes can strongly influence the dissipation of glyphosate and aminomethylphosphonic acid applied with Roundup Max® in agricultural soils; in addition, the soil structure state shortly before erosive precipitations fall can be a key parameter for the distribution of glyphosate and its metabolite. Field rain simulation experiments showed that severe erosion processes immediately after application of Roundup Max® can lead to serious unexpected glyphosate loss even in soils with a high presumed adsorption like the Cambisols, if their structure is unfavourable. In one of the no-tillage-plot of the Cambisol, up to 47% of the applied glyphosate amount was dissipated with surface run-off. Moreover, at the Chernozem site with high erosion risk and lower adsorption potential, glyphosate could be found in collected percolation water transported far outside the 2x2 m experimental plots. Traces of glyphosate were found also outside the treated agricultural fields.

  14. Removal of arsenic and cadmium with sequential soil washing techniques using Na2EDTA, oxalic and phosphoric acid: Optimization conditions, removal effectiveness and ecological risks.

    PubMed

    Wei, Meng; Chen, Jiajun; Wang, Xingwei

    2016-08-01

    Testing of sequential soil washing in triplicate using typical chelating agent (Na2EDTA), organic acid (oxalic acid) and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated by heavy metals close to a mining area. The aim of the testing was to improve removal efficiency and reduce mobility of heavy metals. The sequential extraction procedure and further speciation analysis of heavy metals demonstrated that the primary components of arsenic and cadmium in the soil were residual As (O-As) and exchangeable fraction, which accounted for 60% and 70% of total arsenic and cadmium, respectively. It was determined that soil washing agents and their washing order were critical to removal efficiencies of metal fractions, metal bioavailability and potential mobility due to different levels of dissolution of residual fractions and inter-transformation of metal fractions. The optimal soil washing option for arsenic and cadmium was identified as phosphoric-oxalic acid-Na2EDTA sequence (POE) based on the high removal efficiency (41.9% for arsenic and 89.6% for cadmium) and the minimal harmful effects of the mobility and bioavailability of the remaining heavy metals.

  15. Reactive trace element enrichment in a highly modified, tidally inundated acid sulfate soil wetland: East Trinity, Australia.

    PubMed

    Keene, Annabelle F; Johnston, Scott G; Bush, Richard T; Burton, Edward D; Sullivan, Leigh A

    2010-04-01

    This study examines the abundance of trace elements in surface sediments of a former acid sulfate soil (ASS) wetland subjected to marine tidal inundation. Sediment properties of this highly modified study site are compared with those of an adjacent unmodified, intertidal mangrove forest. Whilst some trace elements (Al, Cd, Mn, Ni and Zn) were clearly depleted due to mobilisation and leaching in the previous oxic-acidic phase, other trace elements (As and Cr) displayed significant enrichment in the tidally inundated ASS. Many trace elements were strongly associated with the reactive Fe and acid volatile sulfide (AVS) fractions, suggesting that trace elements may be adsorbed to abundant reactive Fe phases or sequestered as sulfide minerals. These findings provide an important understanding of the fate and mobility of reactive iron, AVS and trace elements during tidal remediation of a formerly acidified Great Barrier Reef (GBR) catchment.

  16. Impacts of simulated acid rain on recalcitrance of two different soils.

    PubMed

    Dai, Zhongmin; Liu, Xingmei; Wu, Jianjun; Xu, Jianming

    2013-06-01

    Laboratory experiments were conducted to estimate the impacts of simulated acid rain (SAR) on recalcitrance in a Plinthudult and a Paleudalfs soil in south China, which were a variable and a permanent charge soil, respectively. Simulated acid rains were prepared at pH 2.0, 3.5, 5.0, and 6.0, by additions of different volumes of H2SO4 plus HNO3 at a ratio of 6 to 1. The leaching period was designed to represent 5 years of local annual rainfall (1,200 mm) with a 33 % surface runoff loss. Both soils underwent both acidification stages of (1) cation exchange and (2) mineral weathering at SAR pH 2.0, whereas only cation exchange occurred above SAR pH 3.5, i.e., weathering did not commence. The cation exchange stage was more easily changed into that of mineral weathering in the Plinthudult than in the Paleudalfs soil, and there were some K(+) and Mg(2+) ions released on the stages of mineral weathering in the Paleudalfs soil. During the leaching, the release of exchangeable base cations followed the order Ca(2+) >K(+) >Mg(2+) >Na(+) for the Plinthudult and Ca(2+) >Mg(2+) >Na(+) >K(+) for the Paleudalfs soil. The SARs above pH 3.5 did not decrease soil pH or pH buffering capacity, while the SAR at pH 2.0 decreased soil pH and the buffering capacity significantly. We conclude that acid rain, which always has a pH from 3.5 to 5.6, only makes a small contribution to the acidification of agricultural soils of south China in the short term of 5 years. Also, Paleudalfs soils are more resistant to acid rain than Plinthudult soils. The different abilities to prevent leaching by acid rain depend upon the parent materials, types of clay minerals, and soil development degrees.

  17. Carbon and nitrogen mineralization in vineyard acid soils amended with a bentonitic winery waste

    NASA Astrophysics Data System (ADS)

    Fernández-Calviño, David; Rodríguez-Salgado, Isabel; Pérez-Rodríguez, Paula; Díaz-Raviña, Montserrat; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2015-04-01

    Carbon mineralization and nitrogen ammonification processes were determined in different vineyard soils. The measurements were performed in samples non-amended and amended with different bentonitic winery waste concentrations. Carbon mineralization was measured as CO2 released by the soil under laboratory conditions, whereas NH4+ was determined after its extraction with KCl 2M. The time evolution of both, carbon mineralization and nitrogen ammonification, was followed during 42 days. The released CO2 was low in the analyzed vineyard soils, and hence the metabolic activity in these soils was low. The addition of the bentonitic winery waste to the studied soils increased highly the carbon mineralization (2-5 fold), showing that the organic matter added together the bentonitic waste to the soil have low stability. In both cases, amended and non-amended samples, the maximum carbon mineralization was measured during the first days (2-4 days), decreasing as the incubation time increased. The NH4+ results showed an important effect of bentonitic winery waste on the ammonification behavior in the studied soils. In the non-amended samples the ammonification was no detected in none of the soils, whereas in the amended soils important NH4+ concentrations were detected. In these cases, the ammonification was fast, reaching the maximum values of NH4 between 7 and 14 days after the bentonitic waste additions. Also, the percentages of ammonification respect to the total nitrogen in the soil were high, showing that the nitrogen provided by the bentonitic waste to the soil is non-stable. The fast carbon mineralization found in the soils amended with bentonitic winery wastes shows low possibilities of the use of this waste for the increasing the organic carbon pools in the soil.On the other hand, the use of this waste as N-fertilizer can be possible. However, due its fast ammonification, the waste should be added to the soils during active plant growth periods.

  18. Using spin labels to study molecular processes in soils: Covalent binding of aromatic amines to humic acids of soils

    NASA Astrophysics Data System (ADS)

    Aleksandrova, O. N.; Kholodov, V. A.; Perminova, I. V.

    2015-08-01

    Interactions of aliphatic and aromatic amines with soil and humic acids isolated from it are studied by means of spin labels and electron paramagnetic resonance (EPR) spectroscopy. Nitroxyl radicals containing amino groups are used as spin labels. It is found experimentally that aromatic amines are instantaneously converted to the bound state. It is shown that the microareas of their incorporation are characterized by a significant delay in the reduction of the nitroxyl fragment of spin-label molecules, indicating the formation of condensed structures typical of an oxidative binding mechanism. It is concluded that aliphatic amines do not bind to humic acids. It is noted that the studied process allows elucidating the formation of bound xenobiotic residues in soils.

  19. Fatality due to gamma-hydroxybutyric acid (GHB) and heroin intoxication.

    PubMed

    Ferrara, S D; Tedeschi, L; Frison, G; Rossi, A

    1995-05-01

    The first case of fatal intoxication due to ingestion of gamma-hydroxybutyric acid (GHB) and intravenous use of heroin is reported. A 42-year-old man, known to have been a heroin addict and to have taken other psychoactive substances, who had been in treatment with GHB for several months, was found dead. Anatomohistopathologic examination showed generalized visceral congestion, edema and pulmonary anthracosis, chronic bronchitis and chronic active hepatitis. Toxicological findings included fluid and tissue distributions of GHB, morphine and 6-monoacetylmorphine. GHB and morphine concentrations were respectively 11.5 and 0.77 micrograms/mL (blood), 84.3 and 0.3 micrograms/mL (vitreous humor), 258.3 and 1.35 micrograms/mL (urine), 57.0 and 14.3 micrograms/mL (bile), 40.0 and 0.43 micrograms/g (brain), 43.0 and 0.60 micrograms/g (liver), 47.0 and 0.68 micrograms/g (kidney). Blood and urine levels of 6-monoacetylmorphine were 28.5 and 12.1 ng/mL respectively. The presumed mechanism of action and pharmacokinetics of GHB are briefly reviewed, with reference to its therapeutic use and to reports of non-fatal GHB intoxication.

  20. Contribution of ants in modifying of soil acidity and particle size distribution

    NASA Astrophysics Data System (ADS)

    Morgun, Alexandra; Golichenkov, Maxim

    2015-04-01

    Being a natural body, formed by the influence of biota on the upper layers of the Earth's crust, the soil is the most striking example of biogenic-abiogenic interactions in the biosphere. Invertebrates (especially ants that build soil nests) are important agents that change soil properties in well developed terrestrial ecosystems. Impact of soil microorganisms on soil properties is particularly described in numerous literature and concerns mainly chemical properties and general indicators of soil biological activity. Influence of ants (as representatives of the soil mesofauna) mostly appears as mechanical movement of soil particles and aggregates, and chemical effects caused by concentration of organic matter within the ant's nest. The aim of this research was to evaluate the effect of ants on physical and chemical soil attributes such as particle size distribution and soil acidity. The samples were taken from aerial parts of Lasius niger nests, selected on different elements of the relief (summit position, slope, terrace and floodplain) in the Arkhangelsk region (north of the European part of Russia) and compared with the specimens of the upper horizons of the reference soils. Particle size distribution was determined by laser diffraction method using laser diffraction particle size analyzer «Analysette 22 comfort» (FRITSCH, Germany). The acidity (pH) was determined by potentiometry in water suspension. Particle size distribution of the samples from the nests is more variable as compared to the control samples. For example, the content of 5-10 μm fraction ranges from 9% to 12% in reference soils, while in the anthill samples the variation is from 8% to 15%. Similarly, for 50-250 μm fraction - it ranges from 15% to 18% in reference soils, whereas in anthills - from 6% to 29%. The results of particle size analysis showed that the reference sample on the terrace has silty loam texture and nests soil L. niger are medium loam. The reference soil on the slope is

  1. Characterization of humic acids from tundra soils of northern Western Siberia by electron paramagnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Chukov, S. N.; Ejarque, E.; Abakumov, E. V.

    2017-01-01

    Humic acids from polar soils—cryozems (Cryosols), gleyezems (Gleysols), and peat soils (Histosols)—have been studied by electron paramagnetic resonance spectroscopy. First information was acquired on the content of free radicals in humic acids from polar soils for the northern regions of Western Siberia (Gydan Peninsula, Belyi Island). It was found that polar soils are characterized by higher contents of free radicals than other zonal soils. This is related to the lower degree of humification of organic matter and the enhanced hydromorphism under continuous permafrost conditions. The low degree of organic matter humification in the cryolithozone was confirmed by the increased content of free radicals as determined by electron paramagnetic resonance, which indicates a low biothermodynamic stability of organic matter.

  2. The effectiveness of surface liming in ameliorating the phytotoxic effects of soil contaminated by copper acid leach pad solution in an arid ecosystem

    NASA Astrophysics Data System (ADS)

    Golos, Peter

    2016-04-01

    collected at >10 cm depth than the control. Mean soil pH at 0-10 cm was higher (>7.2) at all sites treated with lime compared to uncontaminated soil (5.5). At depths greater than 10 cm soil pH was <4.6. Soil copper was >16 mg/kg in all contaminated soil samples compared to 0.5 mg/kg in control. High seedling mortality in contaminated site is attributed to low soil pH and elevated soil copper levels which inhibited plant root growth and hence access to soil water. While surface liming of soil increased soil pH ameliorating the effect of elevated soil copper, this was only effective in the top 10 cm due to low solubility of hydrated lime. To improve seedling survival lime will need to be incorporated into the contaminated soil profile to allow plants to access soil water at depth. This study highlights the importance of the need to assess the phytotoxic effects of soil contamination and the effectiveness of amelioration treatments and with proper reference to its ecological context. To improve the success of vegetation restoration of sites contaminated with acidic copper solution, lime needs to be incorporated into the contaminated soil profile to allow plant roots to access soil water at depth. This study highlights the importance of the need to assess the phytotoxic effects of soil contamination and the effectiveness of amelioration treatments and with proper reference to its ecological context.

  3. Toxicity of perfluorooctanoic acid towards earthworm and enzymatic activities in soil.

    PubMed

    He, Wenxiang; Megharaj, Mallavarapu; Naidu, Ravi

    2016-07-01

    Perfluorooctanoic acid (PFOA) is a widespread persistent organic contaminant in the environment that has recently raised much of regulatory and public concern. Therefore, assessment of its ecological risk is a top priority research. Hence, this study investigated the toxicity of PFOA to beneficial microbial processes in the soil such as activities of dehydrogenase, urease and potential nitrification in addition to earthworm survival, weight loss and PFOA bioaccumulation in two contrasting soils. In general, PFOA caused inhibition of all the measured microbial processes in a dose-dependent manner and the inhibition was higher in Williamtown (WT) soil than Edinburgh (EB) soil. Thus, WT soil being sandy in nature with low clay content showed higher PFOA bioavailability and hence showed higher toxicity. There was no mortality in earthworms exposed up to 100 mg PFOA/kilogram soil in both the soils; however, there was a significant weight loss from 25 mg/kg onwards. This study clearly demonstrates that soil contamination of PFOA can lead to adverse effects on soil health.

  4. [Effects of different tillage methods on phospholipid fatty acids and enzyme activities in calcareous cinnamon soil].

    PubMed

    Pei, Xue-Xia; Dang, Jian-You; Zhang, Ding-Yi; Wang, Jiao-Ai; Zhang, Jing

    2014-08-01

    In order to study changes of physical and chemical characteristics and microbial activities in soil under different tillage methods, effects of four tillage methods, rotary tillage (RT), subsoil tillage (ST), conventional tillage (CT) with corn straw returned to soil, and rotary tillage with no corn straw returned to soil (CK), on phospholipid fatty acids (PLFA) characteristics and hydrolase enzymes activities in calcareous cinnamon soil were investigated. The results showed that soil hydrolase enzymes activities, nutrient contents, microbial diversity varied greatly with the different tillage methods. Returning corn straw to soil increased the kinds, amount of soil total PLFAs, bacteria PLFAs and actonomycetes PLFAs, while decreased the fungi PLFAs, indicating that fungi was more adaptable than bacteria to an infertile environment. ST and CT resulted in higher amounts of total PLFAs, which were 74.7% and 53.3% higher than that of CK, indicating they were more beneficial to the growth of plants. They could also improve soil physical and chemical properties, increase alk-phosphatase, protease and urease activities, which would provide a favorable soil condition for high and stable crop yields.

  5. Regional trends in soil acidification and exchangeable metal concentrations in relation to acid deposition rates.

    PubMed

    Stevens, Carly J; Dise, Nancy B; Gowing, David J

    2009-01-01

    The deposition of high levels of reactive nitrogen (N) and sulphur (S), or the legacy of that deposition, remain among the world's most important environmental problems. Although regional impacts of acid deposition in aquatic ecosystems have been well documented, quantitative evidence of wide-scale impacts on terrestrial ecosystems is not common. In this study we analysed surface and subsoil chemistry of 68 acid grassland sites across the UK along a gradient of acid deposition, and statistically related the concentrations of exchangeable soil metals (1 M KCl extraction) to a range of potential drivers. The deposition of N, S or acid deposition was the primary correlate for 8 of 13 exchangeable metals measured in the topsoil and 5 of 14 exchangeable metals in the subsoil. In particular, exchangeable aluminium and lead both show increased levels above a soil pH threshold of about 4.5, strongly related to the deposition flux of acid compounds.

  6. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems

    PubMed Central

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N.

    2016-01-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250–2000 μm) and fine sand (53–250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources. PMID:27555553

  7. Distribution patterns of phthalic acid esters in soil particle-size fractions determine biouptake in soil-cereal crop systems

    NASA Astrophysics Data System (ADS)

    Tan, Wenbing; Zhang, Yuan; He, Xiaosong; Xi, Beidou; Gao, Rutai; Mao, Xuhui; Huang, Caihong; Zhang, Hui; Li, Dan; Liang, Qiong; Cui, Dongyu; Alshawabkeh, Akram N.

    2016-08-01

    The use of wastewater irrigation for food crops can lead to presence of bioavailable phthalic acid esters (PAEs) in soils, which increase the potential for human exposure and adverse carcinogenic and non-cancer health effects. This study presents the first investigation of the occurrence and distribution of PAEs in a maize-wheat double-cropping system in a wastewater-irrigated area in the North China Plain. PAE levels in maize and wheat were found to be mainly attributed to PAE stores in soil coarse (250–2000 μm) and fine sand (53–250 μm) fractions. Soil particle-size fractions with higher bioavailability (i.e., coarse and fine sands) showed greater influence on PAE congener bioconcentration factors compared to PAE molecular structures for both maize and wheat tissues. More PAEs were allocated to maize and wheat grains with increased soil PAE storages from wastewater irrigation. Additional findings showed that levels of both non-cancer and carcinogenic risk for PAE congeners in wheat were higher than those in maize, suggesting that wheat food security should be prioritized. In conclusion, increased soil PAE concentrations specifically in maize and wheat grains indicate that wastewater irrigation can pose a contamination threat to food resources.

  8. [Release of Si, Al and Fe in red soil under simulated acid rain].

    PubMed

    Liu, Li; Song, Cun-yi; Li, Fa-sheng

    2007-10-01

    bstract:A laboratory leaching experiment on simulated acid rain was carried out using soil columns. The release of Si, Al and Fe from soils and pH values of eluates were investigated. The results showed that under the given leaching volume, the release amounts of cations were influenced by the pH value of simulated acid rain, while their response to acid rain was different. Acid rain led to Si release, nearly none of Fe. Within the range from pH 3.0 to 5.6, a little Al release but mass Al only release at the pH below 3.0, both Si and Al had a declining release ability with the undergoing eluviation. At pH 2.5, the release amounts of Si and Al, especially Al, increased significantly with the strengthened weathering process of soil mineral. With an increase of the leaching amount of acid rain, the release of Si and Al increased, but acceleration of Si was slower than Al which was slower and slower. When the soil pH falling down to a certain grade, there are negative correlation between pH and both Al and DOC concentration of eluate. released, but most of Al derived from the aluminosilicates dissolved. Acid deposition can result in solid-phase alumino-organics broken and Al released, but most of Al derived from the aluminosilicates dissolved.

  9. Effect of Tannic Acid on the Transcriptome of the Soil Bacterium Pseudomonas protegens Pf-5

    PubMed Central

    Lim, Chee Kent; Penesyan, Anahit; Hassan, Karl A.

    2013-01-01

    Tannins are a diverse group of plant-produced, polyphenolic compounds with metal-chelating and antimicrobial properties that are prevalent in many soils. Using transcriptomics, we determined that tannic acid, a form of hydrolysable tannin, broadly affects the expression of genes involved in iron and zinc homeostases, sulfur metabolism, biofilm formation, motility, and secondary metabolite biosynthesis in the soil- and rhizosphere-inhabiting bacterium Pseudomonas protegens Pf-5. PMID:23435890

  10. Immobilization of lead in anthropogenic contaminated soils using phosphates with/without oxalic acid.

    PubMed

    Su, Xiaojuan; Zhu, Jun; Fu, Qingling; Zuo, Jichao; Liu, Yonghong; Hu, Hongqing

    2015-02-01

    Understanding the effects of oxalic acid (OA) on the immobilization of Pb(II) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(II) by KH2PO4, phosphate rock (PR), activated phosphate rock (APR) and synthetic hydroxyapatite (HAP) at different phosphate:Pb (P:Pb) molar ratios (0, 0.6, 2.0 and 4.0) in the presence/absence of 50 mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or CaCl2, Community Bureau of Reference (BCR) sequential extraction and toxicity characteristic leaching procedure (TCLP) methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after 120 days was reduced by 100% when soils were amended with APR, HAP and HAP+OA, and the TCLP-Pb was <5 mg/L for the red soil at P:Pb molar ratio 4.0. Water-soluble Pb could not be detected and the TCLP-Pb was <5 mg/L at all treatments applied to the yellow-brown soil. BCR results indicated that APR was most effective, although a slight enhancement of water-soluble phosphate was detected at the P:Pb molar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability.

  11. Effects of ammonium application rate on uptake of soil adsorbed amino acids by rice*

    PubMed Central

    Cao, Xiao-chuang; Ma, Qing-xu; Wu, Liang-huan; Zhu, Lian-feng; Jin, Qian-yu

    2016-01-01

    In recent years, excessive use of chemical nitrogen (N) fertilizers has resulted in the accumulation of excess ammonium (NH4 +) in many agricultural soils. Though rice is known as an NH4 +-tolerant species and can directly absorb soil intact amino acids, we still know considerably less about the role of high exogenous NH4 + content on rice uptake of soil amino acids. This experiment examined the effects of the exogenous NH4 + concentration on rice uptake of soil adsorbed glycine in two different soils under sterile culture. Our data showed that the sorption capacity of glycine was closely related to soils’ physical and chemical properties, such as organic matter and cation exchange capacity. Rice biomass was significantly inhibited by the exogenous NH4 + content at different glycine adsorption concentrations. A three-way analysis of variance demonstrated that rice glycine uptake and glycine nutritional contribution were not related to its sorption capacity, but significantly related to its glycine:NH4 + concentration ratio. After 21-d sterile cultivation, the rice uptake of adsorbed glycine accounted for 8.8%‒22.6% of rice total N uptake, which indicates that soil adsorbed amino acids theoretically can serve as an important N source for plant growth in spite of a high NH4 + application rate. However, further studies are needed to investigate the extent to which this bioavailability is realized in the field using the 13C, 15N double labeling technology.

  12. Organic Carbon Stabilization of Soils Formed on Acidic and Calcareous Bedrocks in Neotropical Alpine Grassland, Peru

    NASA Astrophysics Data System (ADS)

    Yang, Songyu; Cammeraat, Erik; Jansen, Boris; Cerli, Chiara; Kalbitz, Karsten

    2016-04-01

    Increasing evidence shows that Neotropical alpine ecosystems are vulnerable to global change. Since soils in the alpine grasslands of the Peruvian Andean region have large soil organic carbon (SOC) stocks, profound understanding of soil organic matter (OM) stabilization mechanisms will improve the prediction of the feedback between SOC stocks and global change. It is well documented that poor-crystalline minerals and organo-metallic complexes significantly contribute to the OM stabilization in volcanic ash soils, including those in the Andean region. However, limited research has focused on non-ash soils that also express significant SOC accumulation. A pilot study of Peruvian Andean grassland soils suggests that lithology is a prominent factor for such carbon accumulation. As a consequence of contrasting mineral composition and pedogenic processes in soils formed on different non-volcanic parent materials, differences in OM stabilization mechanisms may be profound and consequently may respond differently to global change. Therefore, our study aims at a further understanding of carbon stocks and OM stabilization mechanisms in soils formed on contrasting bedrocks in the Peruvian Andes. The main objective is to identify and compare the roles that organo-mineral associations and aggregations play in OM stabilization, by a combination of selective extraction methods and fractionations based on density, particle size and aggregates size. Soil samples were collected from igneous acidic and calcareous sedimentary bedrocks in alpine grassland near Cajamarca, Peru (7.17°S, 78.63°W), at around 3700m altitude. Samples were taken from 3 plots per bedrock type by sampling distinguishable horizons until the C horizons were reached. Outcomes confirmed that both types of soil accumulate large amounts of carbon: 405.3±41.7 t/ha of calcareous bedrock soil and 226.0±5.6 t/ha of acidic bedrock soil respectively. In addition, extremely high carbon contents exceeding 90g carbon per

  13. Simultaneous sorption and desorption of Cd, Cr, Cu, Ni, Pb, and Zn in acid soils II. Soil ranking and influence of soil characteristics.

    PubMed

    Covelo, E F; Vega, F A; Andrade, M L

    2007-08-25

    In Part I of this paper we reported, for each of 11 acid soils, the rankings of six metals according to their sorption from solutions containing all six, and according to their retention under desorption conditions. Here, we analyse the same data from a different perspective: for each metal, we rank the soils by their capacities to sorb and retain it as reflected by soil/solution distribution coefficients K(d100) measured using starting solutions containing 100mgL(-1) of each metal. We also ranked the soils for overall heavy metal sorption and retention capacities using Kaplan's compound measure K(dSigma), and we investigated the influence of soil characteristics on K(d100) and K(dSigma100) values. Overall capacity for sorption of heavy metals was positively related to HOM, kaolinite and Fe oxides contents, and negatively related to CEC and to vermiculite and haematite contents. Overall capacity for retention of heavy metals was positively related to HOM and kaolinite contents, and negatively related to CEC and vermiculite content. The good correlation between K(dSigma100)(sorption) and the first component extracted in a principal components analysis of K(d100)(sorption) values, and between K(dSigma100)(retention) and the first component extracted in a principal components analysis of K(d100)(retention) values, supports the adequacy of K(dSigma) as a measure of the overall capacity of a soil to sorb or retain heavy metals.

  14. A framework for assessing risk reduction due to DNAPL mass removal from low permeability soils

    SciTech Connect

    Freeze, R.A.; McWhorter, D.B.

    1996-08-01

    Many emerging remediation technologies are designed to remove contaminant mass from source zones at DNAPL sites in response to regulatory requirements. There is often concern in the regulated community as to whether mass removal actually reduces risk, or whether the small risk reductions achieved warrant the large costs incurred. This paper sets out a framework for quantifying the degree to which risk is reduced as mass is removed from shallow, saturated, low-permeability, dual-porosity, DNAPL source zones. Risk is defined in terms of meeting an alternate concentration level (ACL) at a compliance well in an aquifer underlying the source zone. The ACL is back-calculated from a carcinogenic health-risk characterization at a downstream water-supply well. Source-zone mass-removal efficiencies are heavily dependent on the distribution of mass between media (fractures, matrix) and phases (dissolved, sorbed, free product). Due to the uncertainties in currently-available technology performance data, the scope of the paper is limited to developing a framework for generic technologies rather than making risk-reduction calculations for specific technologies. Despite the qualitative nature of the exercise, results imply that very high mass-removal efficiencies are required to achieve significant long-term risk reduction with technology, applications of finite duration. 17 refs., 7 figs., 6 tabs.

  15. A conceptual framework: redefining forest soil's critical acid loads under a changing climate.

    PubMed

    McNulty, Steven G; Boggs, Johnny L

    2010-06-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period

  16. Pinus pinaster seedlings and their fungal symbionts show high plasticity in phosphorus acquisition in acidic soils.

    PubMed

    Ali, M A; Louche, J; Legname, E; Duchemin, M; Plassard, C

    2009-12-01

    Young seedlings of maritime pine (Pinus pinaster Soland in Aït.) were grown in rhizoboxes using intact spodosol soil samples from the southwest of France, in Landes of Gascogne, presenting a large variation of phosphorus (P) availability. Soils were collected from a 93-year-old unfertilized stand and a 13-year-old P. pinaster stand with regular annual fertilization of either only P or P and nitrogen (N). After 6 months of culture in controlled conditions, different morphotypes of ectomycorrhiza (ECM) were used for the measurements of acid phosphatase activity and molecular identification of fungal species using amplification of the ITS region. Total biomass, N and P contents were measured in roots and shoots of plants. Bicarbonate- and NaOH-available inorganic P (Pi), organic P (Po) and ergosterol concentrations were measured in bulk and rhizosphere soil. The results showed that bulk soil from the 93-year-old forest stand presented the highest Po levels, but relatively higher bicarbonate-extractable Pi levels compared to 13-year-old unfertilized stand. Fertilizers significantly increased the concentrations of inorganic P fractions in bulk soil. Ergosterol contents in rhizosphere soil were increased by fertilizer application. The dominant fungal species was Rhizopogon luteolus forming 66.6% of analysed ECM tips. Acid phosphatase activity was highly variable and varied inversely with bicarbonate-extractable Pi levels in the rhizosphere soil. Total P or total N in plants was linearly correlated with total plant biomass, but the slope was steep only between total P and biomass in fertilized soil samples. In spite of high phosphatase activity in ECM tips, P availability remained a limiting nutrient in soil samples from unfertilized stands. Nevertheless young P. pinaster seedlings showed a high plasticity for biomass production at low P availability in soils.

  17. Comparison of Copper Sorption on Lignite and on Soils of Different Types and Their Humic Acids

    SciTech Connect

    Pekar, M.; Klucakova, M.

    2008-10-15

    We compared the sorption of copper on South Moravian lignite with that on several soils from Slovakia, using batch adsorption at a laboratory temperature of 25{sup o}C followed by a two-step desorption procedure. The results confirmed that lignite has a copper-sorption capacity and copper-binding strength that is comparable to or better than that of the Slovakian soils that we investigated. We compared these results with previously obtained data for sorption on humic acids (HA) isolated from lignite and soils. Although soil constituents other than HA, such as fulvic acids and mineral particles, also control metal sorption, HA bind copper at higher capacity and with greater strength than do the whole matrices of the soils we tested, and lignite showed a greater binding strength for copper than any of these soils. Our results thus far indicate that natural lignite mined in the Czech Republic, or lignite-derived HA, are potential agents for in situ soil remediation.

  18. Back to Acid Soil Fields: The Citrate Transporter SbMATE Is a Major Asset for Sustainable Grain Yield for Sorghum Cultivated on Acid Soils

    PubMed Central

    Carvalho, Geraldo; Schaffert, Robert Eugene; Malosetti, Marcos; Viana, Joao Herbert Moreira; Menezes, Cicero Bezerra; Silva, Lidianne Assis; Guimaraes, Claudia Teixeira; Coelho, Antonio Marcos; Kochian, Leon V.; van Eeuwijk, Fred A.; Magalhaes, Jurandir Vieira

    2015-01-01

    Aluminum (Al) toxicity damages plant roots and limits crop production on acid soils, which comprise up to 50% of the world’s arable lands. A major Al tolerance locus on chromosome 3, AltSB, controls aluminum tolerance in sorghum [Sorghum bicolor (L.) Moench] via SbMATE, an Al-activated plasma membrane transporter that mediates Al exclusion from sensitive regions in the root apex. As is the case with other known Al tolerance genes, SbMATE was cloned based on studies conducted under controlled environmental conditions, in nutrient solution. Therefore, its impact on grain yield on acid soils remains undetermined. To determine the real world impact of SbMATE, multi-trait quantitative trait loci (QTL) mapping in hydroponics, and, in the field, revealed a large-effect QTL colocalized with the Al tolerance locus AltSB, where SbMATE lies, conferring a 0.6 ton ha–1 grain yield increase on acid soils. A second QTL for Al tolerance in hydroponics, where the positive allele was also donated by the Al tolerant parent, SC283, was found on chromosome 9, indicating the presence of distinct Al tolerance genes in the sorghum genome, or genes acting in the SbMATE pathway leading to Al-activated citrate release. There was no yield penalty for AltSB, consistent with the highly localized Al regulated SbMATE expression in the root tip, and Al-dependent transport activity. A female effect of 0.5 ton ha–1 independently demonstrated the effectiveness of AltSB in hybrids. Al tolerance conferred by AltSB is thus an indispensable asset for sorghum production and food security on acid soils, many of which are located in developing countries. PMID:26681519

  19. Back to Acid Soil Fields: The Citrate Transporter SbMATE Is a Major Asset for Sustainable Grain Yield for Sorghum Cultivated on Acid Soils.

    PubMed

    Carvalho, Geraldo; Schaffert, Robert Eugene; Malosetti, Marcos; Viana, Joao Herbert Moreira; Menezes, Cicero Bezerra; Silva, Lidianne Assis; Guimaraes, Claudia Teixeira; Coelho, Antonio Marcos; Kochian, Leon V; van Eeuwijk, Fred A; Magalhaes, Jurandir Vieira

    2015-12-17

    Aluminum (Al) toxicity damages plant roots and limits crop production on acid soils, which comprise up to 50% of the world's arable lands. A major Al tolerance locus on chromosome 3, AltSB, controls aluminum tolerance in sorghum [Sorghum bicolor (L.) Moench] via SbMATE, an Al-activated plasma membrane transporter that mediates Al exclusion from sensitive regions in the root apex. As is the case with other known Al tolerance genes, SbMATE was cloned based on studies conducted under controlled environmental conditions, in nutrient solution. Therefore, its impact on grain yield on acid soils remains undetermined. To determine the real world impact of SbMATE, multi-trait quantitative trait loci (QTL) mapping in hydroponics, and, in the field, revealed a large-effect QTL colocalized with the Al tolerance locus AltSB, where SbMATE lies, conferring a 0.6 ton ha(-1) grain yield increase on acid soils. A second QTL for Al tolerance in hydroponics, where the positive allele was also donated by the Al tolerant parent, SC283, was found on chromosome 9, indicating the presence of distinct Al tolerance genes in the sorghum genome, or genes acting in the SbMATE pathway leading to Al-activated citrate release. There was no yield penalty for AltSB, consistent with the highly localized Al regulated SbMATE expression in the root tip, and Al-dependent transport activity. A female effect of 0.5 ton ha(-1) independently demonstrated the effectiveness of AltSB in hybrids. Al tolerance conferred by AltSB is thus an indispensable asset for sorghum production and food security on acid soils, many of which are located in developing countries.

  20. Uranium partitioning under acidic conditions in a sandy soil aquifer

    SciTech Connect

    Johnson, W.H. |; Serkiz, S.M.; Johnson, L.M.

    1995-07-01

    The partitioning of uranium in an aquifer down gradient of two large mixed waste sites was examined with respect to the solution and soil chemistry (e.g., pH redox potential and contaminant concentration) and aqueous-phase chemical speciation. This involved generation of field-derived, batch sorption, and reactive mineral surface sorption data. Field-derived distribution coefficients for uranium at these waste sites were found to vary between 0.40 and 15,000. Based on thermodynamic speciation modeling and a comparison of field and laboratory data, gibbsite is a potential reactive mineral surface present in modified soils at the sites. Uranium partitioning data are presented from field samples and laboratory studies of background soil and the mineral surface gibbsite. Mechanistic and empirical sorption models fit to the field-derived uranium partitioning data show an improvement of over two orders of magnitude, as measured by the normalized sum of errors squared, when compared with the single K{sub d} model used in previous risk work. Models fit to batch sorption data provided a better fit of sorbed uranium than do models fit to the field-derived data.

  1. Fractionation of Fe isotopes by soil microbes and organic acids

    USGS Publications Warehouse

    Brantley, Susan L.; Liermann, Laura; Bullen, Thomas D.

    2001-01-01

    Small natural variations in Fe isotopes have been attributed to biological cycling. However, without understanding the mechanism of fractionation, it is impossible to interpret such variations. Here we show that the δ56Fe of Fe dissolved from a silicate soil mineral by siderophore-producing bacteria is as much as 0.8% lighter than bulk Fe in the mineral. A smaller isotopic shift is observed for Fe released abiotically by two chelates, and the magnitude of the shift increases with affinity of the ligand for Fe, consistent with a kinetic isotope effect during hydrolysis of Fe at the mineral surface. Fe dissolved abiotically without chelates shows no isotopic shift. The δ56Fe of the exchange fraction on soil grains is also lighter by ~0.6%-1% than Fe from both hornblende and iron oxyhydroxides. The kinetic isotope effect is therefore preserved in open systems such as soils. when recorded in the rock record, Fe isotopic fractionation could document Fe transport by organic molecules or by microbes where such entities were present in the geologic past.

  2. Studies on radiation dose due to radioactive elements present in ground water and soil samples around Mysore city, India.

    PubMed

    Chandrashekara, M S; Veda, S M; Paramesh, L

    2012-04-01

    A systematic study of the ground water and soil samples collected from different locations around Mysore city (12(°)N and 76(°)E) has been carried out. (226)Ra activity concentration in water samples varies from 0.28 to 189 mBq l(-1) with a geometric mean (GM) of 4.75 mBq l(-1) and (222)Rn concentration in ground water varies from 4.25 to 435 Bq l(-1) with a GM of 25.9 Bq l(-1). The GM of inhalation and ingestion doses due to (222)Rn in water is 65.2 and 5.43, µSv y(-1), respectively. The measured GM gamma dose rate in air is 85.4 nGy h(-1) and absorbed dose rate estimated from the measured activity of radionuclides is 92.6 nGy h(-1).

  3. Active Ammonia Oxidizers in an Acidic Soil Are Phylogenetically Closely Related to Neutrophilic Archaeon

    PubMed Central

    Wang, Baozhan; Zheng, Yan; Huang, Rong; Zhou, Xue; Wang, Dongmei; He, Yuanqiu

    2014-01-01

    All cultivated ammonia-oxidizing archaea (AOA) within the Nitrososphaera cluster (former soil group 1.1b) are neutrophilic. Molecular surveys also indicate the existence of Nitrososphaera-like phylotypes in acidic soil, but their ecological roles are poorly understood. In this study, we present molecular evidence for the chemolithoautotrophic growth of Nitrososphaera-like AOA in an acidic soil with pH 4.92 using DNA-based stable isotope probing (SIP). Soil microcosm incubations demonstrated that nitrification was stimulated by urea fertilization and accompanied by a significant increase in the abundance of AOA rather than ammonia-oxidizing bacteria (AOB). Real-time PCR analysis of amoA genes as a function of the buoyant density of the DNA gradient following the ultracentrifugation of the total DNA extracted from SIP microcosms indicated a substantial growth of soil AOA during nitrification. Pyrosequencing of the total 16S rRNA genes in the “heavy” DNA fractions suggested that archaeal communities were labeled to a much greater extent than soil AOB. Acetylene inhibition further showed that 13CO2 assimilation by nitrifying communities depended solely on ammonia oxidation activity, suggesting a chemolithoautotrophic lifestyle. Phylogenetic analysis of both 13C-labeled amoA and 16S rRNA genes revealed that most of the active AOA were phylogenetically closely related to the neutrophilic strains Nitrososphaera viennensis EN76 and JG1 within the Nitrososphaera cluster. Our results provide strong evidence for the adaptive growth of Nitrososphaera-like AOA in acidic soil, suggesting a greater metabolic versatility of soil AOA than previously appreciated. PMID:24375137

  4. Isolation of fluorescent constituents from soil humic and fulvic acids by hydrophilic interaction chromatography

    NASA Astrophysics Data System (ADS)

    Aoyama, Masakazu

    2014-05-01

    Humic acids (HAs) and fulvic acids (FAs) are the most abundant components of soil organic matter and exhibit fluorescence. Our previous studies using high performance size-exclusion chromatography (HPSEC) and polyacrylamide gel electrophoresis demonstrated that the fluorescence of soil HAs was mainly due to the minor constituents with relatively small molecular sizes. In order to clarify the nature of the fluorescence of soil organic matter, it is necessary to isolate the fluorescent constituents from HAs and FAs. I succeeded in isolating the fluorescent constituents from soil HAs and FAs by using hydrophilic interaction chromatography (HILIC). When HILIC of soil HAs and FAs was carried out under isocratic conditions using a SeQuant ZIC-HILIC column and acetonitrile-water as a mobile phase, the complete separation of fluorescent and non-fluorescent peaks was achieved at the acetonitrile concentration of 90%. Another fluorescent peak was eluted with decreasing concentration of acetonitrile from 90% to 50%. The use of a TSKgel Amide-80 column gave the same results. The best resolution was obtained when HILIC was performed under gradient conditions from 90% to 50% acetonitrile using the ZIC-HILIC and Amide-80 columns linked in series. For both HAs and FAs, a sharp non-fluorescent peak (peak A) followed by a sharp fluorescent peak (peak B) and a broad fluorescent peak (peak C) were eluted under the above optimum operating conditions. The intensity of peak A relative to that of peak B was significantly less in the FAs than in the HAs. The fluorescent peaks (peaks B and C) of the FAs showed considerable UV absorption, whereas those of the HAs did little UV absorption. When the fluorescence emission spectra (excitation at 280 nm) were measured for the fluorescent peaks, two emission peaks were located at 460 and 520 nm for the HAs, while for the FAs, a broad emission peak at 400-450 nm with a small shoulder at around 500 nm was observed. The peaks were collected

  5. Acid drainage from coal mining: Effect on paddy soil and productivity of rice.

    PubMed

    Choudhury, Burhan U; Malang, Akbar; Webster, Richard; Mohapatra, Kamal P; Verma, Bibhash C; Kumar, Manoj; Das, Anup; Islam, Mokidul; Hazarika, Samarendra

    2017-04-01

    Overburden and acid drainage from coal mining is transforming productive agricultural lands to unproductive wasteland in some parts of Northeast India. We have investigated the adverse effects of acid mine drainage on the soil of rice paddy and productivity by comparing them with non-mined land and abandoned paddy fields of Jaintia Hills in Northeast India. Pot experiments with a local rice cultivar (Myngoi) as test crop evaluated biological productivity of the contaminated soil. Contamination from overburden and acid mine drainage acidified the soil by 0.5 pH units, increased the exchangeable Al(3+) content 2-fold and its saturation on clay complexes by 53%. Available sulfur and extractable heavy metals, namely Fe, Mn and Cu increased several-fold in excess of critical limits, while the availability of phosphorus, potassium and zinc contents diminished by 32-62%. The grain yield of rice was 62% less from fields contaminated with acid mine drainage than from fields that have not suffered. Similarly, the amounts of vegetation, i.e. shoots and roots, in pots filled with soil from fields that received acid mine drainage were 59-68% less than from uncontaminated land (average shoot weight: 7.9±2.12gpot(-1); average root weight: 3.40±1.15gpot(-1)). Paddy fields recovered some of their productivity 4years after mining ceased. Step-wise multiple regression analysis affirmed that shoot weight in the pots and grain yield in field were significantly (p<0.01) and positively influenced by the soil's pH and its contents of K, N and Zn, while concentration of S in excess of threshold limits in contaminated soil significantly (p<0.01) reduced the weight of shoots in the pots and grain yield in the field.

  6. Element mobility and partitioning along a soil acidity gradient in central Ontario forests, Canada.

    PubMed

    Watmough, Shaun A

    2008-10-01

    The potential environmental risk posed by metals in forest soils is typically evaluated by modeling metal mobility using soil-solution partitioning coefficients (K(d)), although such information is generally restricted to a few well-studied metals. Soil-solution partitioning coefficients were determined for 17 mineral elements (Al, As, Be, Ba, Ca, Cr, Cu, Fe, Ga, K, Li, Mg, Rb, Sr, Tl, U and V) in A-horizon (0-5 cm) soil at 46 forested sites that border the Precambrian Shield in central Ontario, where soil pH(aq) varied from 3.9 to 8.1. Sites were dominated by mature sugar maple (Acer saccharum Marsh.), white birch (Betula papyrifera Marsh.), balsam fir (Abies balsamea (L.) Mill.) or white pine (Pinus strobus L.). Log K(d) values for all elements could be predicted by empirical linear regression with soil pH (r(2) = 0.17-0.77) independent of forest type, although this relationship was greatly affected by positive relationships between acid-extractable metal concentration and pH(aq) for 13 of the 17 elements. Elements that exhibited strong or moderate (r(2) > 0.29; p < 0.001) relationships with soil pH(aq) in soil water extracts include Al, Ba, Fe, Ga, K, Li, Rb, Tl, V (negative) and Ca (positive). Elemental partitioning in mineral soil was independent of forest type; tree species differed in their response to chemical differences in mineral soil. For example, Rb, Ba, and Sr concentrations in foliage of sugar maple and white birch significantly increased with increasing soil acidity, whereas Rb, Ba, and Sr concentrations in balsam fir and white pine foliage exhibited no response to soil pH(aq). While K(d) values can provide useful information on the potential mobility and bioavailability of mineral elements in forest soils, care must be used when interpreting the relative contribution of solid and aqueous phases to this relationship and the differing responses of vegetation in elemental cycling in forests must also be considered.

  7. Regional scale assessment of soil predictors of groundwater phosphate (P) levels in acidic sandy agricultural soils

    NASA Astrophysics Data System (ADS)

    Mabilde, Lisa

    2016-04-01

    Possible factors affecting the leaching of P to the groundwater in the Belgian sandy area are examined via regression analysis. The main objective is to investigate the dependency of phreatic groundwater phosphate concentrations (Flemish VMM monitoring net, monitoring period 2010-2013) on soil phosphate saturation degree (PSD) (1994-1997 mapping for Flemish Land Agency) (n = 1032). Additionally explored parameters include: depth distributions of Fe- and Al-oxides, sorbed P and phosphate sorption capacity (PSC) and soil pH. Interpolated data of these soil parameters in 3 depth layers (0-30, 30-60, 60-90 cm) were generated by ordinary kriging. Secondly, we assessed the significance of other edaphic factors potentially controlling the groundwater P: topsoil organic carbon content (OC %), soil clay content and fluctuation of the groundwater table. Overall, the mean PSD halved with each 30 cm depth layer (56 > 24 > 13 %) and was correlated to groundwater PO43- level. The statistical significance of the correlation with groundwater PO43- concentrations increased with depth layer. The poor correlation (R2 = 0.01) between PSD and groundwater phosphate concentration indicates that many factors, other than soil P status, control the transport of P from soil solution to the groundwater in Belgian sandy soils. A significant (P<0.01) positive non-linear relationship was found between groundwater PO43-concentration and pHKCl in all three studied depth layers, again increasingly with depth. Within the pH range of the 30-60 cm layer (pHKCl 4.0-5.7) PO4- solubility should increase with pH. Elevated soil OC levels surprisingly co-occurred with low groundwater PO43- concentrations (r = -0.18, P<0.01, n = 191). Groundwater PO43- was furthermore significantly and positively correlated to clay % in both the 0-15 cm (r = 0.15, τ = 0.25, P<0.01, n = 1032) and 60-90 cm (r = 0.13, τ = 0.20, P<0.01, n = 1032) depth increments. These positive correlations were unexpected and could be

  8. Use of Fly Ash as a Liming Material for Corn and Soybean Production on an Acidic Sandy Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fly ash (FA) produced from subbituminous coal combustion can potentially serve as a lime material for crop production in acidic soils in areas. A five-year study was conducted to determine if FA can be used as a liming material in an acid sandy soil under corn and soybean grain production. Fly ash...

  9. Climate dependency of tree growth suppressed by acid deposition effects on soils in Northwest Russia

    USGS Publications Warehouse

    Lawrence, G.B.; Lapenis, A.G.; Berggren, D.; Aparin, B.F.; Smith, K.T.; Shortle, W.C.; Bailey, S.W.; Varlyguin, D.L.; Babikov, B.

    2005-01-01

    Increased tree growth in temperate and boreal forests has been proposed as a direct consequence of a warming climate. Acid deposition effects on nutrient availability may influence the climate dependency of tree growth, however. This study presents an analysis of archived soil samples that has enabled changes in soil chemistry to be tracked with patterns of tree growth through the 20th century. Soil samples collected in 1926, 1964, and 2001, near St. Petersburg, Russia, showed that acid deposition was likely to have decreased root-available concentrations of Ca (an essential element) and increased root-available concentrations of Al (an inhibitor of Ca uptake). These soil changes coincided with decreased diameter growth and a suppression of climate-tree growth relationships in Norway spruce. Expected increases in tree growth from climate warming may be limited by decreased soil fertility in regions of northern and eastern Europe, and eastern North America, where Ca availability has been reduced by acidic deposition. ?? 2005 American Chemical Society.

  10. Improving phosphorus availability in an acid soil using organic amendments produced from agroindustrial wastes.

    PubMed

    Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab

    2014-01-01

    In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

  11. Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

    PubMed Central

    Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

    2014-01-01

    In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments. PMID:25032229

  12. Death of a toddler due to ingestion of sulfuric acid at a clandestine home methamphetamine laboratory.

    PubMed

    Burge, Meredith; Hunsaker, John C; Davis, Gregory J

    2009-12-01

    Exposure to strong acids such as sulfuric acid to either the skin or the gastrointestinal or respiratory mucosa will result respectively in significant-occasionally fatal-cutaneous chemical burns as well as devastating corrosive damage to the respiratory and gastrointestinal tracts. Most injuries are accidental, but there are reports of using acids as weapons or as a means of suicide. The primary mechanism of acid injury is coagulative necrosis of the tissues. Sulfuric acid is a chemical often used in industrial and chemical laboratories, and it is an ingredient in household products like drain cleaner. Easily accessible, over-the-counter, household drain cleaner is one of several common materials used to manufacture methamphetamine. With increasing clandestine methamphetamine laboratories in the United States, exposure to methamphetamine and the toxic chemicals used for its production is a growing problem. In many instances, children living in these laboratories qua homes are at risk for injury and death. We report the death of an unattended toddler, who ingested sulfuric acid drain cleaner in his home. The gross and histopathological autopsy findings in this case are similar to those of previously described cases of sulfuric acid injury.

  13. Search for amino acids in Apollo returned lunar soil.

    PubMed

    Gehrke, C W; Zumwalt, R W; Kuo, K; Ponnamperuma, C; Shimoyama, A

    1975-10-01

    The lunar samples from Apollo flights 11 through 17 provided the students of chemical evolution with an opportunity of examining extraterrestrial materials for evidence of early prebiological chemistry in the solar system. Our search was directed to water-extractable compounds with emphasis on amino acids. Gas chromatography, ion-exchange chromatography and gas chromatography combined with mass spectrometry were used for the analysis. It is our conclusion that amino acids are not present in the lunar regolith above the background levels of our investigations.

  14. Impacts of simulated acid rain on soil enzyme activities in a latosol.

    PubMed

    Ling, Da-Jiong; Huang, Qian-Chun; Ouyang, Ying

    2010-11-01

    Acid rain pollution is a serious environmental problem in the world. This study investigated impacts of simulated acid rain (SAR) upon four types of soil enzymes, namely the catalase, acid phosphatase, urease, and amylase, in a latosol. Latosol is an acidic red soil and forms in the tropical rainforest biome. Laboratory experiments were performed by spraying the soil columns with the SAR at pH levels of 2.5, 3.0, 3.5., 4.0, 4.5, 5.0, and 7.0 (control) over a 20-day period. Mixed results were obtained in enzyme activities for different kinds of enzymes under the influences of the SAR. The catalase activities increased rapidly from day 0 to 5, then decreased slightly from day 5 to 15, and finally decreased sharply to the end of the experiments, whereas the acid phosphatase activities decreased rapidly from day 0 to 5, then increased slightly from day 5 to 15, and finally decreased dramatically to the end of the experiments. A decrease in urease activities was observed at all of the SAR pH levels for the entire experimental period, while an increase from day 0 to 5 and then a decrease from day 5 to 20 in amylase activities were observed at all of the SAR pH levels. In general, the catalase, acid phosphatase, and urease activities increased with the SAR pH levels. However, the maximum amylase activity was found at pH 4.0 and decreased as the SAR pH increased from 4.0 to 5.0 or decreased from 4.0 to 2.5. It is apparent that acid rain had adverse environmental impacts on soil enzyme activities in the latosol. Our study further revealed that impacts of the SAR upon soil enzyme activities were in the following order: amylase>catalase>acid phosphatase>urease. These findings provide useful information on better understanding and managing soil biological processes in the nature under the influence of acid rains.

  15. Uncertainty analysis on simple mass balance model to calculate critical loads for soil acidity.

    PubMed

    Li, Harbin; McNulty, Steven G

    2007-10-01

    Simple mass balance equations (SMBE) of critical acid loads (CAL) in forest soil were developed to assess potential risks of air pollutants to ecosystems. However, to apply SMBE reliably at large scales, SMBE must be tested for adequacy and uncertainty. Our goal was to provide a detailed analysis of uncertainty in SMBE so that sound strategies for scaling up CAL estimates to the national scale could be developed. Specifically, we wanted to quantify CAL uncertainty under natural variability in 17 model parameters, and determine their relative contributions in predicting CAL. Results indicated that uncertainty in CAL came primarily from components of base cation weathering (BC(w); 49%) and acid neutralizing capacity (46%), whereas the most critical parameters were BC(w) base rate (62%), soil depth (20%), and soil temperature (11%). Thus, improvements in estimates of these factors are crucial to reducing uncertainty and successfully scaling up SMBE for national assessments of CAL.

  16. Soil moisture affects fatty acids and oil quality parameters in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought affects yield of peanut, but its effect on oleic and linoleic acids that influence its oil quality of peanut genotypes with different levels of drought resistance has not been clearly investigated. Therefore, the aims of this research were to determine whether soil water levels could affect...

  17. DEVELOPMENTS IN THE SUPERCRITICAL FLUID EXTRACTION OF CHLOROPHENOXY ACID HERBICIDES FROM SOIL SAMPLES

    EPA Science Inventory

    Extraction of chlorophenoxy acid herbicides from soil samples with supercritical carbon dioxide as extractant and tetrabutylammonium hydroxide and methyl iodide as derivatization agents was investigated. The extraction was carried out at 400 atm and 80 C for 15 min static, follow...

  18. Simultaneous Removal of Lindane, Lead and Cadmium from Soils by Rhamnolipids Combined with Citric Acid

    PubMed Central

    Long, Tao; Ying, Rongrong; Ye, Mao; Zhang, Shengtian; Li, Qun; Zhou, Yan; Lin, Yusuo

    2015-01-01

    This study investigated the performance of rhamnolipids-citric acid mixed agents in simultaneous desorption of lindane and heavy metals from soils. The capacity of the mixed agents to solubilize lindane, lead and cadmium in aqueous solution was also explored. The results showed that the presence of citric acid greatly enhanced the solubilization of lindane and cadmium by rhamnolipids. A combined effect of the mixed agents on lindane and heavy metals removal from soils was observed. The maximum desorption ratios for lindane, cadmium and lead were 85.4%, 76.4% and 28.1%, respectively, for the mixed agents containing 1% rhamnolipidsand 0.1 mol/L citric acid. The results also suggest that the removal efficiencies of lead and cadmium were strongly related to their speciations in soils, and metals in the exchangeable and carbonate forms were easier to be removed. Our study suggests that the combining use of rhamnolipids and citric acid is a promising alternative to simultaneously remove organochlorine pesticides and heavy metals from soils. PMID:26087302

  19. Perfluoroalkyl acid distribution in various plant compartments of edible crops grown in biosolids-amended soils

    EPA Science Inventory

    Crop uptake of perfluoroalkyl acids (PFAAs) from biosolids-amended soil has been identified as a potential pathway for PFAA entry into the terrestrial food chain. This study compared the uptake of PFAAs in greenhouse-grown radish (Raphanus sativus), celery (Apium graveolens var.d...

  20. Gas chromatography - optical fiber detector for assessment of fatty acids in urban soils.

    PubMed

    Silva, Lurdes; Cachada, Anabela; Pereira, Ruth; Freitas, Ana Cristina; Rocha-Santos, Teresa A P; Panteleitchouk, Teresa S L; Pereira, Maria E; Duarte, Armando Costa

    2011-07-15

    Fatty acids have been used as biomarkers of the microbial community composition of soils and they are usually separated and quantified by gas-chromatography coupled to a flame ionization detector (GC-FID). The aim of this study was to develop, validate and apply a methodology based on gas chromatography coupled to optical fiber detection (GC-OF) for screening five fatty acids used as indicators of fungal and bacterial communities in urban soils. The performance of the GC-OF methodology (optical fiber detector at 1,550 nm) was evaluated by comparison with the GC-FID methodology and it was found that they were comparable in terms of linear range, detection limit and analytical errors. Besides these similar analytical characteristics, the GC-OF is much cheaper than the GC-FID methodology. Different concentrations were determined for each fatty acid indicator which in turn varied significantly between the soil samples analyzed from Lisbon ornamental gardens. Additionally, the GC-OF showed a great potential as alternative for determination of eleven or more fatty acids in urban soils.

  1. The role of natural purified humic acids in modifying mercury accessibility in water and soil

    SciTech Connect

    Cattani, I.; Zhang, H.; Beone, G.M.; Del Re, A.A.M.; Boccelli, R.; Trevisan, M.

    2009-03-15

    We investigated the influence of different humic acids (HAs, extracted from lignite, compost, and forest soil) on mercury mobility and availability both in a model solution and in soil samples from a mercury-polluted region. The technique of diffusive gradients in thin-films (DGT), which is capable of measuring: (i) free metal in solution: (ii) dissociated metal complexes previously mobilized by HA; (iii) mobilized metal-HA complexes that liberate metals by dissociation or by exchange reaction between the metal-HA complexes and the chelating groups on the resin-gel, was used in solutions and soils. The DGT measurements in solution, together with ultrafiltration, allowed estimation of the lability of Hg-HA complexes. Ultrafiltration results were also compared with predictions made by the windermere humic-aqueous model (WHAM). According to both these different approaches, Hg{sup 2+} resulted nearly 100% complexed by HAs, whereas results from ultrafiltration showed that 32 to 72% of the CH{sub 4}Hg{sup +} was bound to the HAs, with higher values for compost and lower values for forest and Aldrich HA. The DGT-measured mercury in soils was below 0.20 {mu}g L{sup -1}, irrespective of the extent of the contamination. Addition of HA increased the concentration of DGT-measured mercury in soil solution up to 100-fold in the contaminated soil and up to 30-fold in the control soil. The level of the increase also depended on the HA. The smallest increase (about 10 times) was found for lignite HA in both control and contaminated soils. The addition of forest HA gave the largest increases in DGT-measured mercury, in particular for the contaminated soil. Overall, the results demonstrated that DGT can be used for estimating the lability of mercury complexes in solution and for verifying enhanced mercury mobility when HA is added to contaminated soils.

  2. Identification of a new sulfonic acid metabolite of metolachlor in soil

    USGS Publications Warehouse

    Aga, D.S.; Thurman, E.M.; Yockel, M.E.; Zimmerman, L.R.; Williams, T.D.

    1996-01-01

    An ethanesulfonic acid metabolite of metolachlor (metolachlor ESA) was identified in soil-sample extracts by negative-ion, fast-atom bombardment mass spectrometry (FAB-MS) and FAB tandem mass spectrometry (FAB-MS/MS). Production fragments from MS/MS analysis of the deprotonated molecular ion of metolachlor ESA in the soil extract can be reconciled with the structure of the synthesized standard. The elemental compositions of the (M - H)- ions of the metolachlor ESA standard and the soil-sample extracts were confirmed by high-resolution mass spectrometry. A dissipation study revealed that metolachlor ESA is formed in soil under field conditions corresponding to a decrease in the concentration of the parent herbicide, metolachlor. The identification of the sulfonated metabolite of metolachlor suggests that the glutathione conjugation pathway is a common detoxification pathway shared by chloroacetanilide herbicides.

  3. Coapplication of Chicken Litter Biochar and Urea Only to Improve Nutrients Use Efficiency and Yield of Oryza sativa L. Cultivation on a Tropical Acid Soil.

    PubMed

    Maru, Ali; Haruna, Osumanu Ahmed; Primus, Walter Charles

    2015-01-01

    The excessive use of nitrogen (N) fertilizers in sustaining high rice yields due to N dynamics in tropical acid soils not only is economically unsustainable but also causes environmental pollution. The objective of this study was to coapply biochar and urea to improve soil chemical properties and productivity of rice. Biochar (5 t ha(-1)) and different rates of urea (100%, 75%, 50%, 25%, and 0% of recommended N application) were evaluated in both pot and field trials. Selected soil chemical properties, rice plants growth variables, nutrient use efficiency, and yield were determined using standard procedures. Coapplication of biochar with 100% and 75% urea recommendation rates significantly increased nutrients availability (especially P and K) and their use efficiency in both pot and field trials. These treatments also significantly increased rice growth variables and grain yield. Coapplication of biochar and urea application at 75% of the recommended rate can be used to improve soil chemical properties and productivity and reduce urea use by 25%.

  4. Metabolic programming of long-term outcomes due to fatty acid nutrition in early life.

    PubMed

    Innis, Sheila M

    2011-04-01

    Understanding of the importance of dietary fatty acids has grown beyond a simple source of energy to complex roles in regulating gene expression and cell and intracellular communication. This is important because the metabolic and neuroendocrine environment of the fetus and infant plays a key role in guiding the set point of neural receptors that regulate energy homeostasis and expression of genes that control energy storage and oxidation. Early deviations in these pathways have the potential to lead to lasting adaptations, termed metabolic programming, which may combine to increase the risk of metabolic syndrome in later life. The quality of fatty acids in human diets has undergone major changes in the last 50 years, characterized by an increase in ω-6 and decrease in ω-3 fatty acids. Evidence is accumulating to support the concept that the maternal intake of ω-6 and ω-3 fatty acids in gestation and lactation, possibly involving both excess ω-6 and inadequate ω-3 fatty acids, can impact the developing infant tissue lipids and neuroendocrine and metabolic pathways relevant to metabolic programming. Further work is needed to understand the needs for different ω-6 and ω-3 fatty acids during fetal and infant life, and their roles with respect to development of energy homeostasis and metabolism.

  5. Remediation of soils contaminated with chromium using citric and hydrochloric acids: the role of chromium fractionation in chromium leaching.

    PubMed

    Cheng, Shu-Fen; Huang, Chin-Yuan; Tu, Yao-Ting

    2011-01-01

    Acid washing is a common method for soil remediation, but is not always efficient for chromium-contaminated soil. Both soil particle size and the forms of chromium existing in the soil affect the efficiency of soil washing. Laboratory batch and column dissolution experiments were conducted to determine the efficiencies of citric and hydrochloric acids as agents to extract chromium from soils contaminated with chromium. The effects of soil particle size and chromium fractionation on Cr leaching were also investigated. About 90% of chromium in the studied soil existed either in residual form or bound to iron and manganese oxides, and Cr fraction distributions were similar for all soil particle sizes. Almost all exchangeable and carbonate-bound chromium was removed by washing once with 0.5 M HCl, whereas organic chromium was more effectively removed by washing with citric acid rather than with HCl solution of the same concentration. For chromium fractions that were either bound to Fe-Mn oxides or existed as residual forms, the efficiencies of acid washing were usually 20% or less, except for 0.5 M HCl solution, which had much higher efficiencies. Separation of the soil sample by particle size before the separate washing of the soil fractions had little improvement on the chromium removal.

  6. Titanium Mass-balance Analysis of Paso Robles Soils: Elemental Gains and Losses as Affected by Acid Alteration Fluids

    NASA Technical Reports Server (NTRS)

    Sutter, Brad; Ming, Douglas W.

    2010-01-01

    The Columbia Hills soils have been exposed to aqueous alteration in alkaline [1] as well as acid conditions [2,3]. The Paso Robles class soils are bright soils that possess the highest S concentration of any soil measured on Mars [2]. Ferric-sulfate detection by Moessbauer analysis indicated that acid solutions were involved in forming these soils [4]. These soils are proposed to have formed by alteration of nearby rock by volcanic hydrothermal or fumarolic activity. The Paso Robles soils consist of the original Paso Robles-disturbed-Pasadena (PR-dist), Paso Robles- PasoLight (PR-PL), Arad-Samra, Arad-Hula, Tyrone- Berker Island1 and Tyrone-MountDarwin [2 ,3. ]Chemical characteristics indicate that the PR-dist and PR-PL soils could be derived from acid weathering of local Wishstone rocks while the Samra and Hula soils are likely derived from local Algonquin-Iroquet rock [3]. The Paso Robles soils were exposed to acidic sulfur bearing fluids; however, little else is known about the chemistry of the alteration fluid and its effects on the alteration of the proposed parent materials. The objectives of this work are to conduct titanium normalized mass-balance analysis to1) assess elemental gains and losses from the parent materials in the formation of the Paso Robles soils and 2) utilize this information to indicate the chemical nature of the alteration fluids.

  7. The simultaneous quantitation of ten amino acids in soil extracts by mass fragmentography

    NASA Technical Reports Server (NTRS)

    Pereira, W. E.; Hoyano, Y.; Reynolds, W. E.; Summons, R. E.; Duffield, A. M.

    1972-01-01

    A specific and sensitive method for the identification and simultaneous quantitation by mass fragmentography of ten of the amino acids present in soil was developed. The technique uses a computer driven quadrupole mass spectrometer and a commercial preparation of deuterated amino acids is used as internal standards for purposes of quantitation. The results obtained are comparable with those from an amino acid analyzer. In the quadrupole mass spectrometer-computer system up to 25 pre-selected ions may be monitored sequentially. This allows a maximum of 12 different amino acids (one specific ion in each of the undeuterated and deuterated amino acid spectra) to be quantitated. The method is relatively rapid (analysis time of approximately one hour) and is capable of the quantitation of nanogram quantities of amino acids.

  8. Increases in soil water content after the mortality of non-native trees in oceanic island forest ecosystems are due to reduced water loss during dry periods.

    PubMed

    Hata, Kenji; Kawakami, Kazuto; Kachi, Naoki

    2016-03-01

    The control of dominant, non-native trees can alter the water balance of soils in forest ecosystems via hydrological processes, which results in changes in soil water environments. To test this idea, we evaluated the effects of the mortality of an invasive tree, Casuarina equisetifolia Forst., on the water content of surface soils on the Ogasawara Islands, subtropical islands in the northwestern Pacific Ocean, using a manipulative herbicide experiment. Temporal changes in volumetric water content of surface soils at 6 cm depth at sites where all trees of C. equisetifolia were killed by herbicide were compared with those of adjacent control sites before and after their mortality with consideration of the amount of precipitation. In addition, the rate of decrease in the soil water content during dry periods and the rate of increase in the soil water content during rainfall periods were compared between herbicide and control sites. Soil water content at sites treated with herbicide was significantly higher after treatment than soil water content at control sites during the same period. Differences between initial and minimum values of soil water content at the herbicide sites during the drying events were significantly lower than the corresponding differences in the control quadrats. During rainfall periods, both initial and maximum values of soil water contents in the herbicided quadrats were higher, and differences between the maximum and initial values did not differ between the herbicided and control quadrats. Our results indicated that the mortality of non-native trees from forest ecosystems increased water content of surface soils, due primarily to a slower rate of decrease in soil water content during dry periods.

  9. Mid-infrared soil spectral changes due to cultivation, C mineralization, and short-term substrate utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mid infrared diffuse reflectance spectroscopy is a valuable technique for the study of the C quantity and quality of soils. We analyzed soils from two sites (Hoytville, OH, and Akron, CO), under different managements (native, vs. different levels of cultivation). Each soil was also analyzed before a...

  10. Acute generalized exanthematous pustulosis (AGEP) due to exposure to sulfuric acid and bromic acid vapor: a case report.

    PubMed

    Bilac, Dilek Bayraktar; Ermertcan, Aylin Turel; Ozturkcan, Serap; Sahin, M Turhan; Temiz, Peyker

    2008-01-01

    Acute generalized exanthematous pustulosis (AGEP, toxic pustuloderma, pustular drug eruption) is a not uncommon cutaneous reaction pattern that is usually related to drug administration. The eruption is of sudden onset and appears 7-10 days after the medication is started. A 22-year-old male patient who was a student at a chemical faculty attended our outpatient clinic with a complaint of pustular eruption on his face. According to his history, the eruption started with pruritus and erythema on his chin 3 days ago and spread to his face and chest. He explained that he had performed an experiment with sulfuric acid and bromic acid and was exposed to their vapor. His dermatological examination revealed erythema and pustules on his cheeks, on his chin, above his upper lip, and on his eyebrows. He also had a few pustules on his chest. There were no ocular, mucous membrane, or pulmonary symptoms. Histopathological examination of the skin biopsy specimen revealed superficial orthokeratosis, focal subcorneal pustule formation, and perivascular chronic inflammatory cell infiltration in superficial dermis. After administration of systemic antihistamines and wet dressing topically, we observed rapid healing of the lesions. Because there was no systemic drug intake in his history, we were concerned that exposure to sulfuric acid and bromic acid vapor caused AGEP in this patient. We present this rare case to show that the vapor of chemical materials may cause AGEP or other drug eruptions.

  11. Hexavalent uranium diffusion into soils from concentrated acidic and alkaline solutions

    SciTech Connect

    Tokunaga, Tetsu K.; Wan, Jiamin; Pena, Jasquelin; Sutton, Stephen R.; Newville, Matthew

    2004-03-29

    Uranium contamination of soils and sediments often originates from acidic or alkaline waste sources, with diffusion being a major transport mechanism. Measurements of U(VI) diffusion from initially pH 2 and pH 11 solutions into a slightly alkaline Altamont soil and a neutral Oak Ridge soil were obtained through monitoring uptake from boundary reservoirs and from U concentration profiles within soil columns. The soils provided pH buffering, resulting in diffusion at nearly constant pH. Micro x-ray absorption near edge structure spectra confirmed that U remained in U(VI) forms in all soils. Time trends of U(VI) depletion from reservoirs, and U(VI) concentration profiles within soil columns yielded K{sub d} values consistent with those determined in batch tests at similar concentrations ({approx} 1 mM), and much lower than values for sorption at much lower concentrations (nM to {mu}M). These results show that U(VI) transport at high concentrations can be relatively fast at non-neutral pH, with negligible surface diffusion, because of weak sorption.

  12. Soil acidity, ecological stoichiometry and allometric scaling in grassland food webs

    PubMed Central

    MULDER, CHRISTIAN; ELSER, JAMES J

    2009-01-01

    The factors regulating the structure of food webs are a central focus of community and ecosystem ecology, as trophic interactions among species have important impacts on nutrient storage and cycling in many ecosystems. For soil invertebrates in grassland ecosystems in the Netherlands, the site-specific slopes of the faunal biomass to organism body mass relationships reflected basic biochemical and biogeochemical processes associated with soil acidity and soil C : N : P stoichiometry. That is, the higher the phosphorus availability in the soil, the higher, on average, the slope of the faunal biomass size spectrum (i.e., the higher the biomass of large-bodied invertebrates relative to the biomass of small invertebrates). While other factors may also be involved, these results are consistent with the growth rate hypothesis from biological stoichiometry that relates phosphorus demands to ribosomal RNA and protein production. Thus our data represent the first time that ecosystem phosphorus availability has been associated with allometry in soil food webs (supporting information available online). Our results have broad implications, as soil invertebrates of different size have different effects on soil processes.

  13. Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils.

    PubMed

    Li, Yong-Tao; Becquer, Thierry; Dai, Jun; Quantin, Cécile; Benedetti, Marc F

    2009-04-01

    The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils.

  14. Biodegradation of poly(hydroxy butanoic acid) copolymer mulch films in soil

    NASA Astrophysics Data System (ADS)

    Kukade, Pranav

    Agricultural mulch films that are used to cover soil of crop rows contribute to earlier maturation of crops and higher yield. Incineration and landfill disposals are the most common means of disposal of the incumbent polyethylene (PE) mulch films; however, these are not environment friendly options. Biodegradable mulch films that can be rototilled into the soil after crop harvest are a promising alternative to offset problems such as landfill disposal, film retrieval and disposal costs. In this study, an in-house laboratory scale test method was developed in which the rate of disintegration, as a result of biodegradation of films based on polyhydroxybutanoic acid (PHB) copolymers was investigated in a soil environment using the residual weight loss method. The influence of soil composition, moisture levels in the soil, and industry-standard anti-microbial additive in the film composition on the rate of disintegration of PHB copolymer films was investigated. The soil composition has significant effect on the disintegration kinetics of PHB copolymer films, since the increasing compost levels in the soil lowered the rate of disintegration of the film. Also, with the increase in moisture level up to a threshold limit, the microbial activity and, hence, the rate of disintegration increased. Lastly, the developed lab-scale test protocol was found to be sensitive to even small concentrations of industry-standard antimicrobial additive in the film composition.

  15. Transfer of cadmium from a sandy acidic soil to man: A population study

    SciTech Connect

    Staessen, J.A.; Celis, H.G.; Fagard, R.H.; Lijnen, P.J.; Thijs, L.B.; Amery, A.K. ); Vyncke, G. ); Lauwerys, R.R.; Roels, H.A. ); Claeys, F. ); Dondeyne, F. ); Ide, G. ); Rondia, D.; Sartor, F. )

    1992-06-01

    This population study included 230 subjects (age range 20-83 years) who consumed vegetables grown in kitchen gardens on a sandy acidic soil (mean pH {approximately}6.3). The study investigated the association between the Cd (cadmium) levels in blood and urine and the Cd concentration in the soil (range 0.2-44 ppm). Seventy-six subjects were current smokers and 122 participants lived in a district with known Cd pollution. Urinary Cd in the 230 subjects averaged 8.7 nmole/24 hr, (range 1.3 to 47 nmole/24 hr) after age adjustment positively correlated with the Cd level in the soil; a twofold increase of the Cd concentration in the soil was accompanied by a 7% rise in urinary Cd in men and by a 4% rise in women. Blood Cd averaged 11.5 nmole/liter (range 1.8-41 nmole/liter) and was negatively associated with the Cd level in the soil. After adjustment for significant covariates (smoking and serum {gamma}-glutamyl transpeptidase in both sexes, and age and serum ferritin in women), a twofold increase in the Cd concentration in the soil was accompanied by a 6% decrease in blood Cd in men and by a 10% decrease in women. In conclusion, in a rural population, consuming vegetables grown on a sandy acidic soil, 2 to 4% of the variance of urinary Cd was directly related to the Cd level in the soil. The negative correlation with blood Cd, a measure of more recent exposure, was biased by the implementation of preventive measures in the polluted district.

  16. Application of Phospholipid Fatty Acids in the Evaluation of Post-Katrina Wetland Soils

    NASA Astrophysics Data System (ADS)

    Holloway, J. M.; Swarzenski, C. M.; Krauss, K. W.; Doyle, T. W.

    2008-12-01

    The combined effects of Hurricanes Katrina (landfall Aug. 29, 2005) and Rita (landfall Sept. 24, 2005) resulted in a catastrophic loss of wetlands, with an estimated decrease of 562 km2 of land area (Barras, 2006) along the Gulf Coast of Louisiana. A study was initiated following the 2005 hurricane season to characterize storm impacts on coastal marsh soils, measuring soil organic carbon, biogeochemistry of soil pore waters, and soil microbial communities using phospholipids fatty acids (PLFA). Areas selected for study include Caernarvon, which had the greatest land loss through Katrina, and the Barataria Preserve, a unit within the Jean Lafitte National Historic Park. Marshes ranged from fresh water to saline. PLFA concentrations were generally greater in surface soils (28-144 nmol PLFA/g dry soil at 0-5 cm) than deeper soil (27-77 nmol/g at 10-15 cm; 18-20 nmol/g at 35-45 cm) for soils collected in March 2006. There was a notable exception to this trend. The concentration of PLFAs was greater at 15cm (51 nmol/g) than 5cm (28 nmol/g) in a remnant salt marsh soil from Caernarvon. The ratio of 17:0cy/17:0, a stress indicator, was greater in the 5 and 15 cm depths for this soil (6.4 and 7.3, respectively) than in other soils collected at this date (1.9-6.4 at 5 cm; 1.2-5.4 at 15 cm). The inverted PLFA biomass and elevated 17:0cy/17:0 at this location may reflect disturbance from Katrina 6 months after the storm. Differences in microbial community structure were noted between fresh-water and salt marshes, with a general decrease in PLFA concentrations with increasing salinity. A resampling of surface soil in September, 2007 showed an increase in PLFA concentration (64-148 nmol/g) and decreased 17:0cy/17:0 ratio (1.5-3.8). In addition, there were shifts in surface microbial communities, including an increase in a16:0 in fresh water marsh soils and in overall increase in 18:1ωc, a biomarker for eukaryotic microorganisms, including algae and fungi. These shifts may

  17. Entropy reduction in unfolded peptides (and proteins) due to conformational preferences of amino acid residues.

    PubMed

    Schweitzer-Stenner, Reinhard; Toal, Siobhan E

    2014-11-07

    As established by several groups over the last 20 years, amino acid residues in unfolded peptides and proteins do not exhibit the unspecific random distribution as assumed by the classical random coil model. Individual amino acid residues in small peptides were found to exhibit different conformational preferences. Here, we utilize recently obtained conformational distributions of guest amino acid residues in GxG peptides to estimate their conformational entropy, which we find to be significantly lower than the entropy of an assumed random coil like distribution. Only at high temperature do backbone entropies approach random coil like values. We utilized the obtained backbone entropies of the investigated amino acid residues to estimate the loss of conformational entropy caused by a coil → helix transition and identified two subsets of amino acid residues for which the thus calculated entropy losses correlate well with the respective Gibbs energy of helix formation obtained for alanine based host-guest systems. Calculated and experimentally derived entropic losses were found to be in good agreement. For most of the amino acid residues investigated entropic losses derived from our GxG distributions correlate very well with corresponding values recently obtained from MD simulations biased by conformational propensities derived from truncated coil libraries. Both, conformational entropy and the entropy of solvation exhibit a strong, residue specific temperature dependence, which can be expected to substantially affect the stability of unfolded states. Altogether, our results provide strong evidence for the notion that conformational preferences of amino acid residues matter with regard to the thermodynamics of peptide and protein folding.

  18. Health and ecological hazards due to natural radioactivity in soil from mining areas of Nasarawa State, Nigeria.

    PubMed

    Aliyu, Abubakar Sadiq; Ibrahim, Umar; Akpa, Chidozie Timothy; Garba, Nuraddeen Nasiru; Ramli, Ahmad Termizi

    2015-01-01

    Nasarawa State is located in north central Nigeria and it is known as Nigeria's home of solid minerals. It is endowed with barite, copper, zinc, tantalite and granite. Continuous releases of mining waste and tailings into the biosphere may result in a build-up of radionuclides in air, water and soil. This work therefore aims to measure the activity concentration levels of primordial radionuclides in the soil/sediment samples collected from selected mines of the mining areas of Nasarawa State. The paper also assesses the radiological and radio ecological impacts of mining activities on the residents of mining areas and their environment. The activity concentrations of primordial radionuclides ((226)Ra, (232)Th and (40)K) in the surface soils/sediment samples were determined using sodium iodide-thallium gamma spectroscopy. Seven major mines were considered with 21 samples taken from each of the mines for radiochemistry analysis. The human health hazard assessment was conducted using regulatory methodologies set by the United Nations Scientific Committee on the Effects of Atomic Radiation, while the radio ecological impact assessment was conducted using the ERICA tool v. 1.2. The result shows that the activity concentrations of (40)K in the water ways of the Akiri copper and the Azara barite mines are 60 and 67% higher than the world average value for (40)K, respectively. In all mines, the annual effective dose rates (mSv y(-1)) were less than unity, and a maximum annual gonadal dose of 0.58 mSv y(-1) is received at the Akiri copper mine, which is almost twice the world average value for gonadal dose. The external hazard indices for all the mines were less than unity. Our results also show that mollusc-gastropod, insect larvae, mollusc-bivalve and zooplankton are the freshwater biotas with the highest dose rates ranging from 5 to 7 µGy h(-1). These higher dose rates could be associated with zinc and copper mining at Abuni and Akiri, respectively. The most exposed

  19. A laboratory evaluation of the sorption of oil sands naphthenic acids on organic rich soils.

    PubMed

    Janfada, Arash; Headley, John V; Peru, Kerry M; Barbour, S L

    2006-01-01

    The adsorption characteristics of oil sands tailings pond water (OSTPW)-derived naphthenic acids on soils was determined using a batch partitioning method. The adsorption isotherms were found to be linear in all cases. All tests were conducted at 4 degrees C, and at a pH of 8.0 +/- 0.4, which reflects the pH of a tailings settling facility near Fort McMurray, AB. The adsorption characteristics of the naphthenic acids in a synthetic groundwater (SGW) solution was compared to that of the mixture in Milli-Q water. In the presence of SGW, the adsorption coefficient (K(d)) of the mixture of naphthenic acids on soil 1 with a higher organic carbon fraction (f(oc)) was an order of magnitude higher than that observed with the same soil and the Milli-Q water mixture, increasing from 1.9 +/- 0.2 (mL/g) to 17.8 +/- 1.5 (mL/g). The adsorption coefficient of the mixture of naphthenic acids on soil 2, with a lower f(oc), was also observably higher in the SGW mixture, increasing from 1.3 +/- 0.15 (mL/g) to 3.7 +/- 0.2 (mL/g). The relative fractional abundance of the individual naphthenic acids was plotted in order to determine the presence of preferential sorption between individual species within the mixture. It was found that for all Z families (where Z is a measure of the number of rings), naphthenic acids within the carbon number range of 13 to 17 showed preferential sorption. The mixture in SGW showed more pronounced sorption relative to naphthenic acid mixture in Milli-Q water. The results indicate that mixtures of naphthenic acids sorb strongly to soils and that adsorption would be an important attenuating mechanism in groundwater transport. Furthermore, preferential sorption of the individual naphthenic acids is important from a toxicity stand point since different naphthenic acid species have varying degrees of toxicity.

  20. Solid-solution partitioning and thionation of diphenylarsinic acid in a flooded soil under the impact of sulfate and iron reduction.

    PubMed

    Zhu, Meng; Tu, Chen; Hu, Xuefeng; Zhang, Haibo; Zhang, Lijuan; Wei, Jing; Li, Yuan; Luo, Yongming; Christie, Peter

    2016-11-01

    Diphenylarsinic acid (DPAA) is a major organic arsenic (As) compound derived from abandoned chemical weapons. The solid-solution partitioning and transformation of DPAA in flooded soils are poorly understood but are of great concern. The identification of the mechanisms responsible for the mobilization and transformation of DPAA may help to develop effective remediation strategies. Here, soil and Fe mineral incubation experiments were carried out to elucidate the partitioning and transformation of DPAA in anoxic (without addition of sulfate or sodium lactate) and sulfide (with the addition of sulfate and sodium lactate) soil and to examine the impact of sulfate and Fe(III) reduction on these processes. Results show that DPAA was more effectively mobilized and thionated in sulfide soil than in anoxic soil. At the initial incubation stages (0-4weeks), 6.7-74.5% of the total DPAA in sulfide soil was mobilized likely by sorption competition with sodium lactate. At later incubation stage (4-8weeks), DPAA was almost completely released into the solution likely due to the near-complete Fe(III) reduction. Scanning transmission X-ray microscopy (STXM) results provide further direct evidence of elevated DPAA release coupled with Fe(III) reduction in sulfide environments. The total DPAA fraction decreased significantly to 24.5% after two weeks and reached 3.4% after eight weeks in sulfide soil, whereas no obvious elimination of DPAA occurred in anoxic soil at the initial two weeks and the total DPAA fraction decreased to 10.9% after eight weeks. This can be explained in part by the enhanced mobilization of DPAA and sulfate reduction in sulfide soil compared with anoxic soil. These results suggest that under flooded soil conditions, Fe(III) and sulfate reduction significantly promote DPAA mobilization and thionation, respectively, and we suggest that it is essential to consider both sulfate and Fe(III) reduction to further our understanding of the environmental fate of DPAA.

  1. Kinetic study for copper adsorption onto soil minerals in the absence and presence of humic acid.

    PubMed

    Komy, Zanaty R; Shaker, Ali M; Heggy, Said E M; El-Sayed, Mohamed E A

    2014-03-01

    Equilibrium and kinetics of Cu(2+) adsorption onto soil minerals (kaolinite and hematite) in the absence and presence of humic acid have been investigated under various conditions. The influences of ionic strength, pH and solution cations on the rate of the adsorption have been studied. The rate and the amount of adsorbed Cu(2+) onto soil minerals in the absence or the presence of humic acid increased with decreasing ionic strength, increasing pH and in the presence of the background electrolyte K(+) rather than Ca(2+). Humic acid enhanced the rate and the amount of adsorbed Cu(2+) onto soil minerals. The adsorption equilibrium data showed that adsorption behavior of Cu(2+) could be described more reasonably by Langmiur adsorption isotherm than Freundlich isotherm in the absence or presence of humic acid. Pseudo first and pseudo second order models were used to evaluate the kinetic data and the rate constants. The results indicated that the adsorption of Cu(2+) onto hematite and kaolinite in the absence and presence of humic acid is more conforming to pseudo second order kinetics.

  2. Soil acidity amelioration in a no-till system in west Tennessee USA differs by cover crop type and nitrogen application rate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation soil management practices may influence the soil acidity. Surface application of lime may be required in no-till systems to ameliorate soil acidity and to improve crop yields. The application of lime may also increase microbial activity on soil. Specifically, the microbial activity of s...

  3. Fungal populations in podzolic soil experimentally acidified to simulate acid rain

    SciTech Connect

    Baath, E.; Lundgren, B.; Soederstroem, B.

    1984-01-01

    The effect of experimental acidification on the soil microfungal community was studied in the humus layer of a coniferous forest in northern Sweden. The study was made 4 years after the last application of sulfuric acid. Fungal species composition was altered by treatments of 100 and 150 kg sulfuric acid ha/sup -1/ each year for 6 years, yet no differences were found between the control treatment and an application of 50 kg ha/sup -1/. The abundance of Penicillium spinulosum and Oidiodendron cf. echinulatum II increased with increasing rates of acid application, whereas only small changes were found for other isolated fungal taxa. Soil respiration rate and fluorescein diacetate (FDA)-active fungal biomass were significantly different from the control treatment at all 3 levels of acidification. 15 references, 4 tables.

  4. Effects of simulated acid rain on soil and soil solution chemistry in a monsoon evergreen broad-leaved forest in southern China.

    PubMed

    Qiu, Qingyan; Wu, Jianping; Liang, Guohua; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2015-05-01

    Acid rain is an environmental problem of increasing concern in China. In this study, a laboratory leaching column experiment with acid forest soil was set up to investigate the responses of soil and soil solution chemistry to simulated acid rain (SAR). Five pH levels of SAR were set: 2.5, 3.0, 3.5, 4.0, and 4.5 (as a control, CK). The results showed that soil acidification would occur when the pH of SAR was ≤3.5. The concentrations of NO₃(-)and Ca(2+) in the soil increased significantly when the pH of SAR fell 3.5. The concentration of SO₄(2-) in the soil increased significantly when the pH of SAR was <4.0. The effects of SAR on soil solution chemistry became increasingly apparent as the experiment proceeded (except for Na(+) and dissolved organic carbon (DOC)). The net exports of NO₃(-), SO₄(2-), Mg(2+), and Ca(2+) increased about 42-86% under pH 2.5 treatment as compared to CK. The Ca(2+) was sensitive to SAR, and the soil could release Ca(2+) through mineral weathering to mitigate soil acidification. The concentration of exchangeable Al(3+) in the soil increased with increasing the acidity of SAR. The releases of soluble Al and Fe were SAR pH dependent, and their net exports under pH 2.5 treatment were 19.6 and 5.5 times, respectively, higher than that under CK. The net export of DOC was reduced by 12-29% under SAR treatments as compared to CK. Our results indicate the chemical constituents in the soil are more sensitive to SAR than those in the soil solution, and the effects of SAR on soil solution chemistry depend not only on the intensity of SAR but also on the duration of SAR addition. The soil and soil solution chemistry in this region may not be affected by current precipitation (pH≈4.5) in short term, but the soil and soil leachate chemistry may change dramatically if the pH of precipitation were below 3.5 and 3.0, respectively.

  5. Manifestation of Preferential Flow and Nitrate Transport in Central European Soils on Acid Crystalline Rocks

    NASA Astrophysics Data System (ADS)

    Dolezal, F.; Cislerova, M.; Vogel, T.; Zavadil, J.; Vacek, J.; Kvitek, T.; Prazak, P.; Nechvatal, M.; Bayer, T.

    2006-12-01

    Large areas of Central Europe are occupied by highlands and peneplains of medium altitudes, built by acid crystalline rocks. The soils overlying them are typically of medium textures. They are neither markedly water- repellent nor greatly swelling and shrinking. These landscapes are characterized by high vulnerability of water bodies, both surface and subsurface. The existing methodologies of vulnerability assessment regard the heavier among these soils as little vulnerable to diffuse pollution, while in reality they may be virtually equally vulnerable, because of the short-circuiting effect of preferential flow and transport. Our experiment site was Valeèov (49° 38' 40" N, 14° 30' 25" E, 461 m a.s.l.) in the Bohemo-Moravian highland, with average annual precipitation 660 mm and average annual air temperature 7.2 ° C. The field trials, starting from 2001, were focused on growing potato under different conditions. Soil moisture content was measured by Theta- probe capacitance sensors, soil water suction by Watermark sensors and tensiometers. Nitrate leaching was monitored by soil solution sampling with ceramic suction cups and zero-tension lysimeters. The hydraulic conductivity of the soil was measured on small cores and by suction and pressure infiltrometers. The following preferential flow manifestations are analyzed and quantified: a) the spatial variability of soil moisture content and suction after rainstorms, b) the spatial and temporal variability of soil's hydraulic conductivity and its dependence on soil moisture content, c) the spatial variability of percolation volumes in parallel lysimeters, d) the variability of nitrate concentrations in the lysimeter leachate, e) the apparent absence of correlation between leachate volumes and leachate concentrations in lysimeters, f) the lower mean and higher variance of leachate concentrations in lysimeters, in comparison with those in suction cups.

  6. Understory vegetation leads to changes in soil acidity and in microbial communities 27 years after reforestation.

    PubMed

    Fu, Xiaoli; Yang, Fengting; Wang, Jianlei; Di, Yuebao; Dai, Xiaoqin; Zhang, Xinyu; Wang, Huimin

    2015-01-01

    Experiments with potted plants and removed understories have indicated that understory vegetation often affects the chemical and microbial properties of soil. In this study, we examined the mechanism and extent of the influence of understory vegetation on the chemical and microbial properties of soil in plantation forests. The relationships between the vegetational structure (diversity for different functional layers, aboveground biomass of understory vegetation, and species number) and soil properties (pH, microbial community structure, and levels of soil organic carbon, total nitrogen, and inorganic nitrogen) were analyzed across six reforestation types (three pure needleleaf forests, a needle-broadleaf mixed forest, a broadleaf forest, and a shrubland). Twenty-seven years after reforestation, soil pH significantly decreased by an average of 0.95 across reforestation types. Soil pH was positively correlated with the aboveground biomass of the understory. The levels of total, bacterial, and fungal phospholipid fatty acids, and the fungal:bacterial ratios were similar in the shrubland and the broadleaf forest. Both the aboveground biomass of the understory and the diversity of the tree layer positively influenced the fungal:bacterial ratio. Improving the aboveground biomass of the understory could alleviate soil acidification. An increase in the aboveground biomass of the understory, rather than in understory diversity, enhanced the functional traits of the soil microbial communities. The replacement of pure plantations with mixed-species stands, as well as the enhancement of understory recruitment, can improve the ecological functions of a plantation, as measured by the alleviation of soil acidification and increased fungal dominance.

  7. Comparison of natural humic substances and synthetic ethylenediaminetetraacetic acid and nitrilotriacetic acid as washing agents of a heavy metal-polluted soil.

    PubMed

    Soleimani, Mohsen; Hajabbasi, Mohammad A; Afyuni, Majid; Akbar, Samira; Jensen, Julie K; Holm, Peter E; Borggaard, Ole K

    2010-01-01

    Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and other synthetic polycarboxylic acids have been shown to possess substantial capacity as washing agents of heavy metal-polluted soils, but they are environmentally problematic. Therefore, a sample of natural soluble humic substances (HS) was tested as a possible substitute. The efficiency of HS to extract cadmium (Cd), copper (Cu), and lead (Pb) from a strongly polluted calcareous urban soil was compared with that of EDTA and NTA. The influence of extractant concentration (25-100 mmol L(-1) C), solution/soil ratio (5-100 L kg(-1)), and single-step vs. multistep extraction on heavy metal removal from the soil was investigated. The extracted pools were assessed by sequential extraction. Ethylenediaminetetraacetic acid and NTA extracted up to 86, 77, and 30% of total soil Cd, Cu, and Pb, respectively, whereas HS extracted 44, 53, and 4%. Extracted amounts of Cd, Cu, and Pb increased with increasing extractant concentration and solution/soil ratio in the range 5 to 100 L kg(-1). Single-step extraction removed about the same amounts of the three metals as multiple-step extraction. The metal-extracted pools of the soil depended on the metal and on the extractant. The overall conclusion is that soluble HS can replace synthetic EDTA and NTA as washing agents for Cd- and Cu-polluted soils, whereas HS is not a promising substitute of EDTA or NTA for cleaning Pb-polluted, calcareous soils.

  8. Amelioration of acidic soil increases the toxicity of the weak base carbendazim to the earthworm Eisenia fetida.

    PubMed

    Liu, Kailin; Wang, Shaoyun; Luo, Kun; Liu, Xiangying; Yu, Yunlong

    2013-12-01

    Ameliorating acidic soils is a common practice and may affect the bioavailability of an ionizable organic pollutant to organisms. The toxicity of the weak base carbendazim to the earthworm (Eisenia fetida) was studied in an acidic soil (pH-H₂O, 4.6) and in the ameliorated soil (pH-H₂O, 7.5). The results indicated that the median lethal concentration of carbendazim for E. fetida decreased from 21.8 mg/kg in acidic soil to 7.35 mg/kg in the ameliorated soil. To understand why the amelioration increased carbendazim toxicity to the earthworm, the authors measured the carbendazim concentrations in the soil porewater. The authors found increased carbendazim concentrations in porewater, resulting in increased toxicity of carbendazim to earthworms. The increased pore concentrations result from decreased adsorption because of the effects of pH and calcium ions.

  9. Field dissipation of trifloxystrobin and its metabolite trifloxystrobin acid in soil and apples.

    PubMed

    Wang, Chen; Wu, Junxue; Zhang, Yun; Wang, Kai; Zhang, Hongyan

    2015-01-01

    The dissipation of trifloxystrobin and its metabolite trifloxystrobin acid in apples and soil was studied, and the half-life (DT₅₀) was estimated in a field study carried out at three different locations for apples and four different locations for soil. Trifloxystrobin was sprayed on apples at 127 g a.i./ha for the dissipation study. Samples of apple and soil for the dissipation experiment were collected at time intervals of 0, 1, 3, 7, 14, 21, 30, and 45 days after treatment. The quantification of residues was done by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The DT₅₀ of trifloxystrobin ranged from 0.54 to 8.8 and 4.8 to 9.5 days in soil and apples at different latitude sites. Photolysis may be the main dissipation pathway for trifloxystrobin, and the number of sunshine hours may be the main factor affecting the trifloxystrobin dissipation rate in the field. For trifloxystrobin acid residues in soil and apples, it first increased and then began decreasing. It was indicated that the risk of trifloxystrobin application in shorter sunshine hour area should be considered.

  10. [Using kenaf (Hibiscus cannabinus) to reclaim multi-metal contaminated acidic soil].

    PubMed

    Yang, Yu-Xi; Lu, Huan-Liang; Zhan, Shu-Shun; Deng, Teng-hao-bo; Lin, Qing-Qi; Wang, Shi-Zhong; Yang, Xiu-Hong; Qiu, Rong-Liang

    2013-03-01

    A five-year field trial was conducted at the surrounding area of Dabao Mountain Mine to explore the feasibility and availability of using kenaf (Hibiscus cannabinus) , a fiber crop with strong heavy metals tolerance and potential economic value, to reclaim the multi-metal contaminated acidic farmland soil. Different amendments were applied prior to the kenaf planting to evaluate their effects on the soil properties and kenaf growth. After the amendments application, the kenaf could grow well on the heavy metals contaminated soil with the Pb, Zn, Cu, Cd, and As concentrations being 1600, 440, 640, 7. 6, and 850 mg . kg-1, respectively. Among the amendments, dolomite and fly ash had better effects than limestone and organic fertilizer. With the application of dolomite and fly ash, the aboveground dry mass production of kenaf reached 14-15 t . hm-2, which was similar to that on normal soils, and the heavy metal concentrations in the bast fiber and stem of kenaf decreased significantly, as compared with the control. The mass of the bast fiber accounted for 32% -38% of the shoot production, and the extractable heavy metal concentrations in the bast fiber could meet the standard of 'technical specifications of ecological textiles' in China, suggesting that the bast fiber had potential economic value. It was suggested that planting kenaf combining with dolomite/fly ash application could be an effective measure to reclaim the multi-metal contaminated acidic farmland soil.

  11. Modeling the plant-soil interaction in presence of heavy metal pollution and acidity variations.

    PubMed

    Guala, Sebastián; Vega, Flora A; Covelo, Emma F

    2013-01-01

    On a mathematical interaction model, developed to model metal uptake by plants and the effects on their growth, we introduce a modification which considers also effects on variations of acidity in soil. The model relates the dynamics of the uptake of metals from soil to plants and also variations of uptake according to the acidity level. Two types of relationships are considered: total and available metal content. We suppose simple mathematical assumptions in order to get as simple as possible expressions with the aim of being easily tested in experimental problems. This work introduces modifications to two versions of the model: on the one hand, the expression of the relationship between the metal in soil and the concentration of the metal in plants and, on the other hand, the relationship between the metal in the soil and total amount of the metal in plants. The fine difference of both versions is fundamental at the moment to consider the tolerance and capacity of accumulation of pollutants in the biomass from the soil.

  12. Injury and death of various Salmonella serotypes due to acidic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acid injury of Salmonella could prevent detection of Salmonella in feed and feed-type samples. A previous study showed that after incubation in commonly used pre-enrichment media, mixed feeds and feed ingredients reached a pH (4.0 to 5.0) capable of injuring or killing Salmonella. Approximately 10...

  13. Effect of acid rain pH on leaching behavior of cement stabilized lead-contaminated soil.

    PubMed

    Du, Yan-Jun; Wei, Ming-Li; Reddy, Krishna R; Liu, Zhao-Peng; Jin, Fei

    2014-04-30

    Cement stabilization is a practical approach to remediate soils contaminated with high levels of lead. However, the potential for leaching of lead out of these stabilized soils under variable acid rain pH conditions is a major environmental concern. This study investigates the effects of acid rain on the leaching characteristics of cement stabilized lead contaminated soil under different pH conditions. Clean kaolin clay and the same soil spiked with 2% lead contamination are stabilized with cement contents of 12 and 18% and then cured for 28 days. The soil samples are then subjected to a series of accelerated leaching tests (or semi-dynamic leaching tests) using a simulated acid rain leachant prepared at pH 2.0, 4.0 or 7.0. The results show that the strongly acidic leachant (pH ∼2.0) significantly altered the leaching behavior of lead as well as calcium present in the soil. However, the differences in the leaching behavior of the soil when the leachant was mildly acidic (pH ∼4.0) and neutral (pH ∼7.0) prove to be minor. In addition, it is observed that the lead contamination and cement content levels can have a considerable impact on the leaching behavior of the soils. Overall, the leachability of lead and calcium is attributed to the stability of the hydration products and their consequent influence on the soil buffering capacity and structure.

  14. Exchangeable and secondary mineral reactive pools of aluminium in coastal lowland acid sulfate soils.

    PubMed

    Yvanes-Giuliani, Yliane A M; Waite, T David; Collins, Richard N

    2014-07-01

    The use of coastal floodplain sulfidic sediments for agricultural activities has resulted in the environmental degradation of many areas worldwide. The generation of acidity and transport of aluminium (Al) and other metals to adjacent aquatic systems are the main causes of adverse effects. Here, a five-step sequential extraction procedure (SEP) was applied to 30 coastal lowland acid sulfate soils (CLASS) from north-eastern New South Wales, Australia. This enabled quantification of the proportion of aluminium present in 'water-soluble', 'exchangeable', 'organically-complexed', 'reducible iron(III) (oxyhydr)oxide/hydroxysulfate-incorporated' and 'amorphous Al mineral' fractions. The first three extractions represented an average of 5% of 'aqua regia' extractable Al and their cumulative concentrations were extremely high, reaching up to 4000 mg·kg(-1). Comparison of Al concentrations in the final two extractions indicated that 'amorphous Al minerals' are quantitatively a much more important sink for the removal of aqueous Al derived from the acidic weathering of these soils than reducible Fe(III) minerals. Correlations were observed between soil pH, dissolved and total organic carbon (DOC and TOC) and Al concentrations in organic carbon-rich CLASS soil horizons. These results suggest that complexation of Al by dissolved organic matter significantly increases soluble Al concentrations at pH values >5.0. As such, present land management practices would benefit with redefinition of an 'optimal' soil from pH ≥5.5 to ~4.8 for the preservation of aquatic environments adjacent to organic-rich CLASS where Al is the sole or principle inorganic contaminant of concern. Furthermore, it was observed that currently-accepted standard procedures (i.e. 1 M KCl extraction) to measure exchangeable Al concentrations in these types of soils severely underestimate exchangeable Al and a more accurate representation may be obtained through the use of 0.2 M CuCl2.

  15. Growth and survival of cowpea rhizobia in acid, aluminum-rich soils

    SciTech Connect

    Hartel, P.G.; Alexander, M.

    1983-01-01

    A study was undertaken to determine whether Al-sensitive cowpea Rhizobium survives in acid, Al-rich soils. The lower pH limit for growth of 20 strains in a defined liquid medium varied from pH 4.2 to less than pH 3.6. The mean lower limit for growth was pH 3.9. Several of the strains clumped in this medium at pH 4.5. Of 11 strains that were tested for tolerance to high levels of Al in a defined liquid medium at pH 4.5, nine tolerated 75 ..mu..M Al, and the other two were sensitive to levels above 15 ..mu..M. Three strains, one Al-tolerant, one Al-sensitive, and one Al-tolerant or Al-sensitive depending on the presence of vitamins in the medium, were selected for studies in Al-rich sterile and nonsterile soils. These rhizobia did not survive in soils of less than pH 4.7 sterilized by /sup 60/Co irradiation. When inoculated into sterile soil at pH 4.7, the consistently sensitive strain initially failed to proliferate and then grew slowly, but populations of the other two rhizobia increased rapidly. No consistent relationship was found between the Al tolerance of these three rhizobia and their growth and survival in four acid, Al-rich soils. The data suggest that Al is of minor importance to growth and survival of cowpea Rhizobium strains in acid soils. 16 references, 4 figures, 1 table.

  16. Different low-molecular-mass organic acids specifically control leaching of arsenic and lead from contaminated soil.

    PubMed

    Ash, Christopher; Tejnecký, Václav; Borůvka, Luboš; Drábek, Ondřej

    2016-04-01

    Low-molecular-mass organic acids (LMMOA) are of key importance for mobilisation and fate of metals in soil, by functioning as ligands that increase the amount of dissolved metal in solution or by dissociation of metal binding minerals. Column leaching experiments were performed on soil polluted with As and Pb, in order to determine the specificity of LMMOA related release for individual elements, at varying organic acid concentrations. Acetic, citric and oxalic acids were applied in 12h leaching experiments over a concentration range (0.5-25 mM) to soil samples that represent organic and mineral horizons. The leaching of As followed the order: oxalic>citric>acetic acid in both soils. Arsenic leaching was attributed primarily to ligand-enhanced dissolution of mineral oxides followed by As released into solution, as shown by significant correlation between oxalic and citric acids and content of Al and Fe in leaching solutions. Results suggest that subsurface mineral soil layers are more vulnerable to As toxicity. Leaching of Pb from both soils followed the order: citric>oxalic>acetic acid. Mineral soil samples were shown to be more susceptible to leaching of Pb than samples characterised by a high content of organic matter. The leaching efficiency of citric acid was attributed to formation of stable complexes with Pb ions, which other acids are not capable of. Results obtained in the study are evidence that the extent of As and Pb leaching in contaminated surface and subsurface soil depends significantly on the types of carboxylic acid involved. The implications of the type of acid and the specific element that can be mobilised become increasingly significant where LMMOA concentrations are highest, such as in rhizosphere soil.

  17. Different low-molecular-mass organic acids specifically control leaching of arsenic and lead from contaminated soil

    NASA Astrophysics Data System (ADS)

    Ash, Christopher; Tejnecký, Václav; Borůvka, Luboš; Drábek, Ondřej

    2016-04-01

    Low-molecular-mass organic acids (LMMOA) are of key importance for mobilisation and fate of metals in soil, by functioning as ligands that increase the amount of dissolved metal in solution or by dissociation of metal binding minerals. Column leaching experiments were performed on soil polluted with As and Pb, in order to determine the specificity of LMMOA related release for individual elements, at varying organic acid concentrations. Acetic, citric and oxalic acids were applied in 12 h leaching experiments over a concentration range (0.5-25 mM) to soil samples that represent organic and mineral horizons. The leaching of As followed the order: oxalic > citric > acetic acid in both soils. Arsenic leaching was attributed primarily to ligand-enhanced dissolution of mineral oxides followed by As released into solution, as shown by significant correlation between oxalic and citric acids and content of Al and Fe in leaching solutions. Results suggest that subsurface mineral soil layers are more vulnerable to As toxicity. Leaching of Pb from both soils followed the order: citric > oxalic > acetic acid. Mineral soil samples were shown to be more susceptible to leaching of Pb than samples characterised by a high content of organic matter. The leaching efficiency of citric acid was attributed to formation of stable complexes with Pb ions, which other acids are not capable of. Results obtained in the study are evidence that the extent of As and Pb leaching in contaminated surface and subsurface soil depends significantly on the types of carboxylic acid involved. The implications of the type of acid and the specific element that can be mobilised become increasingly significant where LMMOA concentrations are highest, such as in rhizosphere soil.

  18. Lime and compost promote plant re-colonization of metal-polluted, acidic soils.

    PubMed

    Ulriksen, Christopher; Ginocchio, Rosanna; Mench, Michel; Neaman, Alexander

    2012-09-01

    The revegetation of soils affected by historic depositions of an industrial complex in Central Chile was studied. The plant re-colonization from the existing soil seed bank and changes in the physico-chemical properties of the soil were evaluated in field plots amended with lime and/or compost. We found that the application of lime and/or compost decreased the Cu2+ ion activity in the soil solution and the exchangeable Cu in the soil, showing an effective Cu immobilization in the topsoil. Whereas lime application had no effect on plant productivity in comparison with the unamended control, the application of compost and lime+compost increased the plant cover and aboveground biomass due to the higher nutrient availability and water-holding capacity of the compost-amended soils. Although the Cu2+ activity and the exchangeable Cu were markedly lower in the amended soils than in the unamended control, the shoot Cu concentrations of Lolium spp. and Eschscholzia californica did not differ between the treatments.

  19. Alpine pasture soils accumulate a large fraction of labile carbon due to combined effects of low temperature, low pH, and poor litter quality on decomposition

    NASA Astrophysics Data System (ADS)

    Budge, Karen; Leifeld, Jens; Hiltbrunner, Erika; Fuhrer, Jürg

    2010-05-01

    Alpine soils are expected to contain large amounts of labile carbon (C) which may result in a further increase in atmospheric CO2 levels in response to global warming. However, there is little data available on these soils and limited understanding of the influence environmental factors have on soil organic matter (SOM) turnover. We extracted 30 cm deep soil cores from 5 sites along an elevation gradient of an alpine pasture in the central Swiss Alps. Soil fractions obtained by size and density fractionation revealed a high proportion of labile particulate organic carbon (POC), particularly in the uppermost soil layers. POC values in the top 20 cm across the gradient of 2285-2653 m above sea level (a.s.l.) ranged from 39.6-57.6 % in comparison to 7.2-29.6 reported in lower elevation soils of 810-1960 m a.s.l. in previous studies. While soil at all elevations was found to be relatively acidic, C mean residence times (MRTs) were considerably shorter and phytomass was slightly higher at the single site found to have a comparatively less acidic soil pH, although SOC content did not vary from those sites of similar root/litter and stone contents. At all elevations, MRTs increased between fractions of increasing stability from free POM (fPOM) → occluded POM (oPOM) → mineral-associated material (mOM); e.g. at 2653 m MRTs increased in years from 90 in fPOM → 117 in oPOM → 534 in mOM. Depending on elevation and pH, plant community data indicated considerable variation in the source of litter input. The lowest site was dominated by sedges whereas the highest site by lichens and dwarf shrubs, this variation in litter source may be reflected in the dynamics of soil C. While temperature is likely to be a major influence in the low turnover rate observed, other factors such as litter quality and soil pH as well as the combination of these factors are likely to play an important role on the response of SOM in the event of soil warming and require consideration in model

  20. [Relationships between soil moisture and needle-fall in Masson pine forests in acid rain region of Chongqing, Southwest China].

    PubMed

    Wang, Yi-Hao; Wang, Yan-Hui; Li, Zhen-Hua; Yu, Peng-Tao; Xiong, Wei; Hao, Jia; Duan, Jian

    2012-10-01

    From March 2009 to November 2011, an investigation was conducted on the spatiotemporal variation of soil moisture and its effects on the needle-fall in Masson pine (Pinus massoniana) forests in acid rain region of Chongqing, Southeast China, with the corresponding soil moisture thresholds determined. No matter the annual precipitation was abundant, normal or less than average, the seasonal variation of soil moisture in the forests could be obviously divided into four periods, i.e., sufficient (before May), descending (from June to July), drought (from August to September), and recovering (from October to November). With increasing soil depth, the soil moisture content increased after an initial decrease, but the difference of the soil moisture content among different soil layers decreased with decreasing annual precipitation. The amount of monthly needle-fall in the forests in growth season was significantly correlated with the water storage in root zone (0-60 cm soil layer), especially in the main root zone (20-50 cm soil layer). Soil field capacity (or capillary porosity) and 82% of field capacity (or 80% of capillary porosity) were the main soil moisture thresholds affecting the litter-fall. It was suggested that in acid rain region, Masson pine forest was easily to suffer from water deficit stress, especially in dry-summer period. The water deficit stress, together with already existed acid rain stress, would further threaten the health of the Masson forest.

  1. Effect of EDTA and citric acid on phytoremediation of Cr- B[a]P-co-contaminated soil.

    PubMed

    Chigbo, Chibuike; Batty, Lesley

    2013-12-01

    Polycyclic aromatic hydrocarbons and heavy metals in the environment are a concern, and their removal to acceptable level is required. Phytoremediation, the use of plants to treat contaminated soils, could be an interesting alternative to conventional remediation processes. This work evaluates the role of single and combined applications of chelates to single or mixed Cr + benzo[a]pyrene (B[a]P)-contaminated soil. Medicago sativa was grown in contaminated soil and was amended with 0.3 g citric acid, 0.146 g ethylenediaminetetraacetic acid (EDTA), or their combination for 60 days. The result shows that in Cr-contaminated soil, the application of EDTA + citric acid significantly (p<0.05) decreased the shoot dry matter of M. sativa by 55 % and, as such, decreased the Cr removal potential from the soil. The soluble Cr concentration in single Cr or Cr + B[a]P-contaminated soil was enhanced with the amendment of all chelates; however, only the application of citric acid in Cr-contaminated soil (44 %) or EDTA and EDTA + citric acid in co-contaminated soil increased the removal of Cr from the soil (34 and 54 %, respectively). The dissipation of B[a]P in single B[a]P-contaminated soil was effective even without planting and amendment with chelates, while in co-contaminated soil, it was related to the application of either EDTA or EDTA + citric acid. This suggests that M. sativa with the help of chelates in single or co-contaminated soil can be effective in phytoextraction of Cr and promoting the biodegradation of B[a]P.

  2. Soil washing of chromium- and cadmium-contaminated sludge using acids and ethylenediaminetetra acetic acid chelating agent.

    PubMed

    Gitipour, Saeid; Ahmadi, Soheil; Madadian, Edris; Ardestani, Mojtaba

    2016-01-01

    In this research, the effect of soil washing in the removal of chromium- and cadmium-contaminated sludge samples collected from Pond 2 of the Tehran Oil Refinery was investigated. These metals are considered as hazardous substances for human health and the environment. The carcinogenicity of chromate dust has been established for a long time. Cadmium is also a potential environmental toxicant. This study was carried out by collecting sludge samples from different locations in Pond 2. Soil washing was conducted to treat the samples. Chemical agents, such as acetic acid, ethylenediaminetetra acetic acid (EDTA) and hydrochloric acid, were used as washing solutions to remove chromium and cadmium from sludge samples. The results of this study indicated that the highest removal efficiencies from the sludge samples were achieved using a 0.3 M HCl solution with 82.69% and 74.47% for chromium and cadmium, respectively. EDTA (0.1 M) in the best condition extracted 66.81% of cadmium and 72.52% of chromium from the sludges. The lowest efficiency values for the samples, however, were achieved using 3 M acetic acid with 41.7% and 46.96% removals for cadmium and chromium, respectively. The analysis of washed sludge indicated that the heavy metals removal decreased in the order of 3 M acetic acid < 0.1 M EDTA<0.3 M HCl, thus hydrochloric acid appears to offer a greater potential as a washing agent in remediating the sludge samples.

  3. Microbial Substrate Usage Indicated by C-14 Contents of Phospholipid Fatty Acids From Soil Organic Matter

    NASA Astrophysics Data System (ADS)

    Rethemeyer, J.; Nadeau, M. J.; Grootes, P. M.; Kramer, C.; Gleixner, G.

    2004-05-01

    Phospholipid fatty acids (PLFA's) are generally associated with viable (bacterial) cell membranes. They are thought to be short-lived under normal soil conditions. We compare the C-14 levels in PLFA's obtained from soil samples from the,clean" experimental site at Rotthalmünster (Germany) with those from the agricultural research station at Halle (Germany), where the soil is contaminated with,old" carbon from lignite mining and industry. The most abundant PLFA's were isolated via preparative capillary gas chromatography of their methyl-esters at the Max-Planck Institute, Jena, and their C-14 concentration was determined via accelerator mass spectrometry at the Leibniz-Labor, Kiel. The C-14 levels of three mono-unsaturated fatty acids (n-C17:1, n-C18:1 (and n-C16:1)) are not statistically significant different from those of the contemporaneous atmosphere, indicating these fatty acids were derived from fresh plant material. C-14 levels significantly above those of the atmosphere in three saturated fatty acids (i/a-C15:0, n-C16:0 and cy-C18:0) from the surface soil of Rotthalmünster must derive from carbon fixed from the atmosphere several years earlier, when levels of bomb-C-14, remaining from the atmospheric nuclear weapons tests, especially of the early 1960's, were still higher. Lower C-14 levels in the same compounds from the Halle surface soil indicate the incorporation of "old" contaminant carbon. A below- atmospheric C-14 concentration in n-C18:0 in Rotthalmünster surface soil may reflect the partial incorporation of carbon from older, pre-bomb times. The C-14 concentrations show these PLFA's were synthesized predominantly from recent to sub-recent photosynthetic compounds, while the significant differences in C-14 concentration, observed between the PLFA's, indicate their production from soil organic matter fractions of different (recent) age and C-14 content. The Halle results show "old" carbon may be incorporated into PLFA's and thus reenter the soil

  4. Short and long term changes in carbon, nitrogen and acidity in the forest soils under oak at the Alice Holt Environmental Change Network site.

    PubMed

    Benham, S E; Vanguelova, E I; Pitman, R M

    2012-04-01

    The dynamics of soil properties within a 70 year old oak plot were assessed every five years (1994-2009), by depth and by horizon to identify short term changes in soil carbon and nitrogen stocks, and acidity. The findings were set within a study of long term changes in soil properties in a 180 year chronosequence of oak plots from the same forest. Carbon stock increased significantly in the top mineral horizon - overall increase was 5 t C ha(-1), at a mean accumulation rate of 0.34 t C ha(-1)y(-1), which was mainly due to increase in horizon thickness. No increase was seen when soils were sampled by depth. Differences obtained by depth or horizon sampling due to changes in horizon thickness over time highlight the importance of horizon in the correct evaluation of soil property change in small scale sampling programs. This is particularly important in forest soils with high litter accumulation and low turnover rates when compared to other land uses. Nitrogen stock increases below 10cm soil depth were attributed to insect activity, litterfall variation and a change in water table. Findings were confirmed in the chronosequence study of oak across the forests; increases in soil C stocks of 0.1-0.2 t C ha(-1)y(-1) were calculated across young (~25 years), mid-rotation (~60 years) and old (120+ years) stands. Soil nitrogen increased significantly with canopy age whilst pH increased significantly between young-mid rotation stands but decreased between mid rotation and old stands. Significant increases in pH were also recorded before 2004 in the ECN 70 year old oak plots reflecting overall pollution recovery.

  5. [Cd uptake in rice cultivars and Cd fractions in soil treated with organic acids and EDTA].

    PubMed

    Zhang, Hai-Bo; Li, Yang-Rui; Xu, Wei-Hong; Chen, Gui-Qing; Wang, Hui-Xian; Han, Gui-Qi; Zhang, Xiao-Jing; Xiong, Zhi-Ting; Zhang, Jin-Zhong; Xie, De-Ti

    2011-09-01

    A pot experiment was conducted to examine the yield, quality and cadmium (Cd) uptake in different rice cultivars, and Cd speciation in soil after exposing to Cd (0, 1 and 5 mg x kg(-1)) in the presence of organic acids and ethylenediamine tetraacetic acid (EDTA). The results showed that general increase in the yield for cultivars Xiushui63 and II you527 was observed. Yield of two rice cultivars were in order of organic acids treatment or organic acids + 1/2EDTA treatment > EDTA treatment. The exchangeable, carbonate related and ferric-manganese oxidation related Cd increased; while organic complexation Cd and residules decreased in the presence of organic acids and EDTA. Cadmium concentrations in grain, straw and roots of both cultivars markedly reduced in the presence of organic acids and EDTA. Grain Cd concentration was the lowest for plants treated with EDTA, followed by organic acids + 1/2EDTA, and the highest Cd concentration in grain was found in the treatment with organic acids. Grain Cd concentration decreased by 9.0% to 49.3% and 16.5% to 30.6% at 1 mg x kg(-1) Cd in the presence of organic acids and EDTA, and by 12.7% to 28.5% and 4.3% to 19.1% at 5 mg x kg(-1) Cd. Cadmium concentration and accumulation in plants and total Cd content in soil were higher in Xiushui63 than in that in II you527. Grain Cd concentration decreased, and yield and quality of two rice cultivars increased at the same time in the presence of organic acids + 1/2EDTA.

  6. Chronic suppurative otitis media due to nontuberculous mycobacteria: A case of successful treatment with topical boric acid.

    PubMed

    Lefebvre, Marie-Astrid; Quach, Caroline; Daniel, Sam J

    2015-07-01

    Nontuberculous mycobacteria (NTM) are an increasingly recognized cause of chronic suppurative otitis media in children with tympanostomy tubes. Treatment of this condition is difficult and typically requires a combination of systemic antibiotics and surgical debridement. We present the first case of a 2-year-old male with chronic suppurative otitis media due to NTM who failed systemic antibiotic therapy and was successfully managed with topical boric acid powder. This report highlights the challenges involved in treating this infection, and introduces boric acid as a potentially valuable component of therapy.

  7. Persistence of glyphosate and aminomethylphosphonic acid in loess soil under different combinations of temperature, soil moisture and light/darkness.

    PubMed

    Bento, Célia P M; Yang, Xiaomei; Gort, Gerrit; Xue, Sha; van Dam, Ruud; Zomer, Paul; Mol, Hans G J; Ritsema, Coen J; Geissen, Violette

    2016-12-01

    The dissipation kinetics of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) were studied in loess soil, under biotic and abiotic conditions, as affected by temperature, soil moisture (SM) and light/darkness. Nonsterile and sterile soil samples were spiked with 16mgkg(-1) of glyphosate, subjected to three SM contents (20% WHC, 60% WHC, saturation), and incubated for 30days at 5°C and 30°C, under dark and light regimes. Glyphosate and AMPA dissipation kinetics were fit to single-first-order (SFO) or first-order-multicompartment (FOMC) models, per treatment combination. AMPA kinetic model included both the formation and decline phases. Glyphosate dissipation kinetics followed SFO at 5°C, but FOMC at 30°C. AMPA followed SFO dissipation kinetics for all treatments. Glyphosate and AMPA dissipation occurred mostly by microbial activity. Abiotic processes played a negligible role for both compounds. Under biotic conditions, glyphosate dissipation and AMPA formation/dissipation were primarily affected by temperature, but also by SM. Light regimes didn't play a significant role. Glyphosate DT50 varied between 1.5 and 53.5days, while its DT90 varied between 8.0 and 280days, depending on the treatment. AMPA persisted longer in soil than glyphosate, with its DT50 at 30°C ranging between 26.4 and 44.5days, and its DT90 between 87.8 and 148days. The shortest DT50/DT90 values for both compounds occurred at 30°C and under optimal/saturated moisture conditions, while the largest occurred at 5°C and reaching drought stress conditions. Based on these results, we conclude that glyphosate and AMPA dissipate rapidly under warm and rainy climate conditions. However, repeated glyphosate applications in fallows or winter crops in countries where cold and dry winters normally occur could lead to on-site soil pollution, with consequent potential risks to the environment and human health. To our knowledge, this study is the first evaluating the combined effect of

  8. Co-composting of acid waste bentonites and their effects on soil properties and crop biomass.

    PubMed

    Soda, Wannipa; Noble, Andrew D; Suzuki, Shinji; Simmons, Robert; Sindhusen, La-Ait; Bhuthorndharaj, Suwannee

    2006-01-01

    Acid waste bentonite is a byproduct from vegetable oil bleaching that is acidic (pH < 3.0) and hydrophobic. These materials are currently disposed of in landfills and could potentially have a negative impact on the effective function of microbes that are intolerant of acidic conditions. A study was undertaken using three different sources of acid waste bentonites, namely soybean oil bentonite (SB), palm oil bentonite (PB), and rice bran oil bentonite (RB). These materials were co-composted with rice husk, rice husk ash, and chicken litter to eliminate their acid reactivity and hydrophobic nature. The organic carbon (OC) content, pH, exchangeable cations, and cation exchange capacity (CEC) of the acid-activated bentonites increased significantly after the co-composting phase. In addition, the hydrophobic nature of these materials as measured using the water drop penetration time (WDPT) decreased from >10 800 s to 16 to 80 s after composting. Furthermore, these composted materials showed positive impacts on soil physical attributes including specific surface area, bulk density, and available water content for crop growth. Highly significant increases in maize biomass (Zea mays L.) production over two consecutive cropping cycles was observed in treatments receiving co-composted bentonite. The study clearly demonstrates the potential for converting an environmentally hazardous material into a high-quality soil conditioner using readily available agricultural byproducts. It is envisaged that the application of these composted acid waste bentonites to degraded soils will increase productivity and on-farm income, thus contributing toward food security and poverty alleviation.

  9. Adsorption and degradation of phenoxyalkanoic acid herbicides in soils: A review.

    PubMed

    Paszko, Tadeusz; Muszyński, Paweł; Materska, Małgorzata; Bojanowska, Monika; Kostecka, Małgorzata; Jackowska, Izabella

    2016-02-01

    The primary aim of the present review on phenoxyalkanoic acid herbicides-2-(2,4-dichlorophenoxy) acetic acid (2,4-D), 2-(4-chloro-2-methylphenoxy) acetic acid (MCPA), (2R)-2-(2,4-dichlorophenoxy) propanoic acid (dichlorprop-P), (2R)-2-(4-chloro-2-methylphenoxy) propanoic acid (mecoprop-P), 4-(2,4-dichlorophenoxy) butanoic acid (2,4-DB), and 4-(4-chloro-2-methylphenoxy) butanoic acid (MCPB)-was to compare the extent of their adsorption in soils and degradation rates to assess their potential for groundwater contamination. The authors found that adsorption decreased in the sequence of 2,4-DB > 2,4-D > MCPA > dichlorprop-P > mecoprop-P. Herbicides are predominantly adsorbed as anions-on organic matter and through a water-bridging mechanism with adsorbed Fe cations-and their neutral forms are adsorbed mainly on organic matter. Adsorption of anions of 2,4-D, MCPA, dichlorprop-P, and mecoprop-P is inversely correlated with their lipophilicity values, and modeling of adsorption of the compounds based on this relationship is possible. The predominant dissipation mechanism of herbicides in soils is bacterial degradation. The contribution of other mechanisms, such as degradation by fungi, photodegradation, or volatilization from soils, is much smaller. The rate of bacterial degradation decreased in the following order: 2,4-D > MCPA > mecoprop-P > dichlorprop-P. It was found that 2,4-D and MCPA have the lowest potential for leaching into groundwater and that mecoprop-P and dichlorprop-P have slightly higher potential. Because of limited data on adsorption and degradation of 2,4-DB and MCPB, estimation of their leaching potential was not possible.

  10. Influence of the selective EDTA derivative phenyldiaminetetraacetic acid on the speciation and extraction of heavy metals from a contaminated soil.

    PubMed

    Zhang, Tao; Wei, Hang; Yang, Xiu-Hong; Xia, Bing; Liu, Jun-Min; Su, Cheng-Yong; Qiu, Rong-Liang

    2014-08-01

    The development of more selective chelators for the washing of heavy metal contaminated soil is desirable in order to avoid excessive dissolution of soil minerals. Speciation and mobility of Cu, Zn, Pb, and Ni in a contaminated soil washed with phenyldiaminetetraacetic acid (PDTA), a derivative of EDTA, were investigated by batch leaching test using a range of soil washing conditions followed by sequential extraction. With appropriate washing conditions, PDTA significantly enhanced extraction of Cu from the contaminated soil. The primary mechanisms of Cu extraction by PDTA were complexation-promoted dissolution of soil Cu and increased dissolution of soil organic matter (SOM). PDTA showed high selectivity for Cu(II) over soil component cations (Ca(II), Mg(II), Fe(III), Mn(II), Al(III)), especially at lower liquid-to-soil ratios under PDTA deficiency, thus avoiding unwanted dissolution of soil minerals during the soil washing process which can degrade soil structure and interfere with future land use. PDTA-enhanced soil washing increased the exchangeable fractions of Cu, Zn, and Pb and decreased their residual fractions, compared to their levels in unwashed soil.

  11. Stomatal response of an anisohydric grapevine cultivar to evaporative demand, available soil moisture and abscisic acid.

    PubMed

    Rogiers, Suzy Y; Greer, Dennis H; Hatfield, Jo M; Hutton, Ron J; Clarke, Simon J; Hutchinson, Paul A; Somers, Anthony

    2012-03-01

    Stomatal responsiveness to evaporative demand (air vapour pressure deficit (VPD)) ranges widely between species and cultivars, and mechanisms for stomatal control in response to VPD remain obscure. The interaction of irrigation and soil moisture with VPD on stomatal conductance is particularly difficult to predict, but nevertheless is critical to instantaneous transpiration and vulnerability to desiccation. Stomatal sensitivity to VPD and soil moisture was investigated in Semillon, an anisohydric Vitis vinifera L. variety whose leaf water potential (Ψ(l)) is frequently lower than that of other grapevine varieties grown under similar conditions in the warm grape-growing regions of Australia. A survey of Semillon vines across seven vineyards revealed that, regardless of irrigation treatment, midday Ψ(l) was dependent on not only soil moisture but VPD at the time of measurement. Predawn Ψ(l) was more closely correlated to not only soil moisture in dry vineyards but to night-time VPD in drip-irrigated vineyards, with incomplete rehydration during high night-time VPD. Daytime stomatal conductance was low only under severe plant water deficits, induced by extremes in dry soil. Stomatal response to VPD was inconsistent across irrigation regime; however, in an unirrigated vineyard, stomatal sensitivity to VPD-the magnitude of stomatal response to VPD-was heightened under dry soils. It was also found that stomatal sensitivity was proportional to the magnitude of stomatal conductance at a reference VPD of 1kPa. Exogenous abscisic acid (ABA) applied to roots of Semillon vines growing in a hydroponic system induced stomatal closure and, in field vines, petiole xylem sap ABA concentrations rose throughout the morning and were higher in vines with low Ψ(l). These data indicate that despite high stomatal conductance of this anisohydric variety when grown in medium to high soil moisture, increased concentrations of ABA as a result of very limited soil moisture may augment

  12. Nutrients, heavy metals and phthalate acid esters in solar greenhouse soils in Round-Bohai Bay-Region, China: impacts of cultivation year and biogeography.

    PubMed

    Chen, Zhiqun; Tian, Tian; Gao, Lihong; Tian, Yongqiang

    2016-07-01

    Solar greenhouse is a common facility type used for horticultural crop production in China. However, most solar greenhouse fields have been degraded due to continuous cropping and excessive fertilizer use. Therefore, we investigated solar greenhouse soils covering a wide range of cultivation years and environmental conditions in Round-Bohai Bay-Region to test the effects of cultivation year and biogeography on nutrients, heavy metals, and phthalate acid esters (PAEs). In general, soil pH decreased while soil electrical conductivity (EC), organic matter (OM), total nitrogen (TN), NO3 (-)-N, NH4 (+)-N, mineral nitrogen (MN), Olsen-P, and NH4OAc-K contents increased as time of cultivation increased. However, this trend was influenced by sampling sites. Among sampling sites, Jiangsu showed a relatively low soil pH and high Olsen-P content, while Hebei showed a relatively high soil EC value, NO3 (-)-N, NH4 (+)-N, MN, and NH4OAc-K contents. Liaoning was characterized by relatively high soil OM and TN contents. The nutrient level indexes in evaluation of soil quality on Olsen-P and NH4OAc-K exceeded the standard seriously. The maximum values of the heavy metals Cd, Cu, and Zn were 4.87, 2.78, and 1.15 times higher than the threshold values, respectively. There was a rising trend on the heavy metal contents with the increasing cultivation years, and this trend was significantly influenced by sampling sites. Both Cu and Zn had relative high heavy metal indexes in evaluation of soil pollution. The PAEs were not detected in almost all sampling soils. Overall, the excessive fertilizer application was an important cause of nutrient accumulation and heavy metal pollution, resulting in soil degradation in solar greenhouses.

  13. Gasified grass and wood biochars facilitate plant establishment in acid mine soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thousands of abandoned mines in the Western U.S. threaten ecosystems, due to high heavy metal concentrations in exposed mine spoils and waters flowing from them. Biochars derived from the pyrolysis or gasification of organic biomass may serve as a valuable soil amendment to revegetate mine sites, du...

  14. Effects of peat fires on the characteristics of humic acid extracted from peat soil in Central Kalimantan, Indonesia.

    PubMed

    Yustiawati; Kihara, Yusuke; Sazawa, Kazuto; Kuramitz, Hideki; Kurasaki, Masaaki; Saito, Takeshi; Hosokawa, Toshiyuki; Syawal, M Suhaemi; Wulandari, Linda; Hendri I; Tanaka, Shunitz

    2015-02-01

    When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.

  15. Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

    SciTech Connect

    Seol, Yongkoo; Javandel, Iraj

    2008-03-15

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  16. Calcium ion binding to a soil fulvic acid using a donnan potential model

    USGS Publications Warehouse

    Marinsky, J.A.; Mathuthu, A.; Ephraim, J.H.; Reddy, M.M.

    1999-01-01

    Calcium ion binding to a soil fulvic acid (Armadale Bh Horizon) was evaluated over a range of calcium ion concentrations, from pH 3.8 to 7.3, using potentiometric titrations and calcium ion electrode measurements. Fulvic acid concentration was constant (100 milligrams per liter) and calcium ion concentration varied up to 8 X 10-4 moles per liter. Experiments discussed here included: (1) titrations of fulvic acid-calcium ion containing solutions with sodium hydroxide; and (2) titrations of fully neutralized fulvic acid with calcium chloride solutions. Apparent binding constants (expressed as the logarithm of the value, log ??app) vary with solution pH, calcium ion concentration, degree of acid dissociation, and ionic strength (from log ??app = 2.5 to 3.9) and are similar to those reported by others. Fulvic acid charge, and the associated Donnan Potential, influences calcium ion-fulvic acid ion pair formation. A Donnan Potential corrrection term allowed calculation of intrinsic calcium ion-fulvic acid binding constants. Intrinsic binding constants vary from 1.2 to 2.5 (the average value is about log??= 1.6) and are similar to, but somewhat higher than, stability constants for calcium ion-carboxylic acid monodentate complexes. ?? by Oldenbourg Wissenschaftsverlag, Mu??nchen.

  17. DEVELOPMENT OF MULTI-PHASE AND MULTI-COMPONENT FLOW MODEL WITH REACTION IN POROUS MEDIA FOR RISK ASSESSMENT ON SOIL CONTAMINATION DUE TO MINERAL OIL

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yasuhide; Nishiwaki, Junko; Hara, Junko; Kawabe, Yoshishige; Sugai, Yuichi; Komai, Takeshi

    In late years, soil contamination due to mineral oil in vacant lots of oil factory and oil field has become obvious. Measure for soil contamina tion and risk assessment are neces sary for sustainable development of industrial activity. Especially, in addition to contaminated sites, various exposure paths for human body such as well water, soil and farm crop are supposed. So it is very important to comprehend the transport phenomena of contaminated material under the environments of soil and ground water. In this study, mineral oil as c ontaminated material consisting of mu lti-component such as aliphatic and aromatic series was modeled. Then numerical mode l for transport phenomena in surface soil and aquifer was constructed. On the basis of modeling for mineral oil, our numerical model consists of three-phase (oil, water and gas) forty three-component. This numerical model becomes base program for risk assessment system on soil contamination due to mineral oil. Using this numerical model, we carried out some numerical simulation for a laboratory-scale experiment on oil-water multi-phase flow. Relative permeability that dominate flow behavior in multi-phase condition was formulated and the validity of the numerical model developed in this study was considered.

  18. Activation of the biochemical processes in an oil-contaminated soil using a light-correcting film and humic acids

    NASA Astrophysics Data System (ADS)

    Filatov, D. A.; Ivanov, A. A.; Svarovskaya, L. I.; Yudina, N. V.

    2011-02-01

    It was shown that the use of a light-correcting film as a covering material for an oil-contaminated soil in combination with humic acids increased the number of the main physiological groups of the soil microorganisms responsible for the development of the soil's fertility (heterotrophic bacteria, actinomycetes, and micromycetes) by 60-100 times. The activity of the soil enzymes (catalase, dehydrogenase, polyphenoloxidase, peroxidase, and urease) increased by 3-6 times. The biochemical oxidation of oil hydrocarbons in the soil became significantly more intense.

  19. Graft Loss Due to Percutaneous Sclerotherapy of a Lymphocele Using Acetic Acid After Renal Transplantation

    SciTech Connect

    Adani, Gian Luigi Baccarani, Umberto; Bresadola, Vittorio; Lorenzin, Dario; Montanaro, Domenico; Risaliti, Andrea; Terrosu, Giovanni; Sponza, Massimo; Bresadola, Fabrizio

    2005-12-15

    Development of lymphoceles after renal transplantation is a well-described complication that occurs in up to 40% of recipients. The gold standard approach for the treatment of symptomatic cases is not well defined yet. Management options include simple aspiration, marsupialization by a laparotomy or laparoscopy, and percutaneous sclerotherapy using different chemical agents. Those approaches can be associated, and they depend on type, dimension, and localization of the lymphocele. Percutaneous sclerotherapy is considered to be less invasive than the surgical approach; it can be used safely and effectively, with low morbidity, in huge, rapidly accumulating lymphoceles. Moreover, this approach is highly successful, and the complication rate is acceptable; the major drawback is a recurrence rate close to 20%. We herewith report a renal transplant case in which the patient developed a symptomatic lymphocele that was initially treated by ultrasound-guided percutaneous sclerotherapy with ethanol and thereafter using acetic acid for early recurrence. A few hours after injection of acetic acid in the lymphatic cavity, the patient started to complain of acute pain localized to the renal graft and fever. An ultrasound of the abdomen revealed thrombosis of the renal vein and artery. The patient was immediately taken to the operating room, where the diagnosis of vascular thrombosis was confirmed and the graft was urgently explanted. In conclusion, we strongly suggest avoiding the use of acetic acid as a slerosating agent for the percutaneous treatment of post-renal transplant lymphocele because, based on our experience, it could be complicated by vascular thrombosis of the kidney, ending in graft loss.

  20. Soil acidity determines the effectiveness of an organic amendment and a native bacterium for increasing soil stabilisation in semiarid mine tailings.

    PubMed

    Carrasco, L; Caravaca, F; Azcón, R; Roldán, A

    2009-01-01

    Unstable mine tailings are vulnerable to water and air erosion, so it is important to promote their surface stabilisation in order to avoid the spread of heavy metals. In a greenhouse experiment, we assessed the effect of the addition of Aspergillus niger-treated sugar beet waste and inoculation with a native bacterium, Bacillus cereus, on the stabilisation of soil aggregates of two acidic, semiarid mine tailings, with different acidity degree, during watering and drying periods. Organic amendment raised the pH of both the moderately and highly acidic tailings, whereas the bacterial inoculation increased this parameter in the former. Only the amendment addition increased soil water-soluble carbon in both tailings compared with their controls, under either watering or drying conditions. Both the amendment and B. cereus enhanced water-soluble carbohydrates. Both treatments increased dehydrogenase activity and aggregate stability, particularly in the moderately acidic tailing under drying conditions. After soil drying, aggregate stability was increased by the amendment (about 66% higher than the control soil) and by the bacterium (about 45% higher than the control soil) in the moderately acidic tailing. The effectiveness of these treatments as structure-stabilisation methods for degraded, semiarid mine ecosystems appears to be restricted to tailings of moderate acidity.

  1. The response of amino acid cycling to global change across multiple biomes: Feedbacks on soil nitrogen availability

    NASA Astrophysics Data System (ADS)

    Brzostek, E. R.; Finzi, A. C.

    2010-12-01

    The cycling of organic nitrogen (N) in soil links soil organic matter decomposition to ecosystem productivity. Amino acids are a key pool of organic N in the soil, whose cycling is sensitive to alterations in microbial demand for carbon and N. Further, the amino acids released from the breakdown of protein by proteolytic enzymes are an important source of N that supports terrestrial productivity. The objective of this study was to measure changes in amino acid cycling in response to experimental alterations of precipitation and temperature in twelve global change experiments during the 2009 growing season. The study sites ranged from arctic tundra to xeric grasslands. The treatments experimentally increased temperature, increased or decreased precipitation, or some combination of both factors. The response of amino acid cycling to temperature and precipitation manipulations tended to be site specific, but the responses could be placed into a common framework. Changes in soil moisture drove a large response in amino acid cycling. Precipitation augmentation in xeric and mesic sites increased both amino acid pool sizes and production. However, treatments that decreased precipitation drove decreases in amino acid cycling in xeric sites, but led to increases in amino acid cycling in more mesic sites. Across sites, the response to soil warming was horizon specific. Amino acid cycling in organic rich horizons responded positively to warming, while negative responses were exhibited in lower mineral soil horizons. The variable response likely reflects a higher availability of protein substrate to sustain high rates of proteolytic enzyme activity in organic rich horizons. Overall, these results suggest that soil moisture and the availability of protein substrate may be important factors that mediate the response of amino acid cycling to predicted increases in soil temperatures.

  2. Nitrogen mineralization rates of the acidic, xeric soils of the New Jersey Pinelands: field rates

    SciTech Connect

    Poovarodom, S.; Tate, R.L. III; Bloom, R.A.

    1988-04-01

    Using the buried-bag procedure, the authors quantified nitrogen mineralization rates in the xeric, acidic Lakehurst, and Atsion sands of the New Jersey Pine Barrens. Average annual nitrogen yields in the upper 15 cm for the Lakehurst and the Atsion sands were 38.4 and 53.0 kg N/ha, corresponding to 4.5 and 2.5% of the total nitrogen, respectively. Net nitrogen mineralization in both soils exhibited distinct seasonal patterns with maxima in summer and minimum rates in the winter. Nitrification accounted for only 5% of the total N mineralized in both soils. This is consistent with the finding of low populations of autotrophic nitrifiers in these soils.

  3. Effectiveness of amendments on re-acidification and heavy metal immobilization in an extremely acidic mine soil.

    PubMed

    Yang, S X; Li, J T; Yang, B; Liao, B; Zhang, J T; Shu, W S

    2011-07-01

    Previous studies have shown that the application of soil amendments is efficient in reducing acidity and heavy metal bioavailability in mine soils. However, it remains a challenge for environmentalists to predict accurately and control economically the re-acidification in re-vegetated mine soils. In this study, net acid generation (NAG) test and bioassay technique were employed to assess the effectiveness of the amendments [including lime, N-P-K (nitrogen, phosphorous and potassium) fertilizer, phosphate and river sediment] on re-acidification and heavy metal immobilization in an extremely acid (pH < 3) mine soil. Our results suggested that NAG test was a rapid and accurate approach to assess the effectiveness of the amendments on re-acidification potential of the mine soil. Interestingly, it was found that phosphate and river sediment played quite specific roles in preventing the re-acidification in the mine soil. In addition, the results also indicated that the addition of 25 t ha(-1) lime combined with river sediment (30%) might be an economical method to successfully control the acidification and re-acidification in the extremely acid mine soil, allowing the re-establishment of the plants. Collectively, our results implied that the combined use of NAG test and bioassay assessment was effective in evaluating a reclamation strategy for extremely acidic mine soils.

  4. Microbial rRNA: rDNA gene ratios may be unexpectedly low due to extracellular DNA preservation in soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We tested a method of estimating the activity of detectable individual bacterial and archaeal OTUs within a community by calculating ratios of absolute 16S rRNA to rDNA copy numbers. We investigated phylogenetically coherent patterns of activity among soil prokaryotes in non-growing soil communitie...

  5. Analysis of perfluorinated carboxylic acids in soils II: optimization of chromatography and extraction.

    PubMed

    Washington, John W; Henderson, W Matthew; Ellington, J Jackson; Jenkins, Thomas M; Evans, John J

    2008-02-15

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorooctanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography-tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C(18) stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/microL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise contrast. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl-tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: (1) alkaline pretreatment; (2) extraction with acetonitrile/water; (3) evaporation to dryness; (4) reconstitution with tetrabutylammonium-hydrogen-sulfate ion-pairing solution; (5) ion-pair extraction to methyl-tert-butyl ether; (6) evaporation to dryness; (7) reconstitution with 60/40 acetonitrile/water (v/v); and (8) analysis by LC/MS/MS. Using this method, we

  6. The leaching of vanadium(V) in soil due to the presence of atmospheric carbon dioxide and ammonia.

    PubMed

    Mandiwana, Khakhathi L; Panichev, Nikolay

    2009-10-30

    The natural leaching of vanadium(V) with CO2 from soil-water in the presence of ammonia, a known precursor to atmospheric aerosols, has been tested by bubbling carbon dioxide through soil suspension with varying amount of ammonia. It was found that the leaching of V(V) is enhanced in the presence of ammonia. From the results of the investigation, it could be concluded that atmospheric CO2 in the presence of ammonia (the only atmospheric gas that increases the pH of soil-water) could naturally leach V(V) from soil. Furthermore, it was also shown that the presence of (NH4)2CO3 in soil could enhance the leaching of toxic V(V) species thereby making it bioavailable for both plants and animals.

  7. Lead binding to soil fulvic and humic acids: NICA-Donnan modeling and XAFS spectroscopy.

    PubMed

    Xiong, Juan; Koopal, Luuk K; Tan, WenFeng; Fang, LinChuan; Wang, MingXia; Zhao, Wei; Liu, Fan; Zhang, Jing; Weng, LiPing

    2013-10-15

    Binding of lead (Pb) to soil fulvic acid (JGFA), soil humic acids (JGHA, JLHA), and lignite-based humic acid (PAHA) was investigated through binding isotherms and XAFS. Pb binding to humic substances (HS) increased with increasing pH and decreasing ionic strength. The NICA-Donnan model described Pb binding to the HS satisfactorily. The comparison of the model parameters showed substantial differences in median Pb affinity constants among JGFA, PAHA, and the soil HAs. Milne's "generic" parameters did not provide an adequate prediction for the soil samples. The Pb binding prediction with generic parameters for the soil HAs was improved significantly by using the value n(Pb1) = 0.92 instead of the generic value n(Pb1) = 0.60. The n(Pb1)/n(H1) ratios obtained were relatively high, indicating monodentate Pb binding to the carboxylic-type groups. The nPb2/nH2 ratios depended somewhat on the method of optimization, but the values were distinctly lower than the n(Pb1)/nH1 ratios, especially when the optimization was based on Pb bound vs log [Pb(2+)]. These low values indicate bidentate binding to the phenolic-type groups at high Pb concentration. The NICA-Donnan model does not consider bidentate binding of Pb to a carboxylic- and a phenolic-type group. The EXAFS results at high Pb loading testified that Pb was bound in bidentate complexes of one carboxylic and one phenolic group (salicylate-type) or two phenolic groups (catechol-type) in ortho position.

  8. Impairment of soil health due to fly ash-fugitive dust deposition from coal-fired thermal power plants.

    PubMed

    Raja, R; Nayak, A K; Shukla, A K; Rao, K S; Gautam, Priyanka; Lal, B; Tripathi, R; Shahid, M; Panda, B B; Kumar, A; Bhattacharyya, P; Bardhan, G; Gupta, S; Patra, D K

    2015-11-01

    Thermal power stations apart from being source of energy supply are causing soil pollution leading to its degradation in fertility and contamination. Fine particle and trace element emissions from energy production in coal-fired thermal power plants are associated with significant adverse effects on human, animal, and soil health. Contamination of soil with cadmium, nickel, copper, lead, arsenic, chromium, and zinc can be a primary route of human exposure to these potentially toxic elements. The environmental evaluation of surrounding soil of thermal power plants in Odisha may serve a model study to get the insight into hazards they are causing. The study investigates the impact of fly ash-fugitive dust (FAFD) deposition from coal-fired thermal power plant emissions on soil properties including trace element concentration, pH, and soil enzymatic activities. Higher FAFD deposition was found in the close proximity of power plants, which led to high pH and greater accumulation of heavy metals. Among the three power plants, in the vicinity of NALCO, higher concentrations of soil organic carbon and nitrogen was observed whereas, higher phosphorus content was recorded in the proximity of NTPC. Multivariate statistical analysis of different variables and their association indicated that FAFD deposition and soil properties were influenced by the source of emissions and distance from source of emission. Pollution in soil profiles and high risk areas were detected and visualized using surface maps based on Kriging interpolation. The concentrations of chromium and arsenic were higher in the soil where FAFD deposition was more. Observance of relatively high concentration of heavy metals like cadmium, lead, nickel, and arsenic and a low concentration of enzymatic activity in proximity to the emission source indicated a possible link with anthropogenic emissions.

  9. Mapping of Acid Sulfate Soils in Finland: determining of areas of risks and compiling guidelines for environmental protection and safe land use

    NASA Astrophysics Data System (ADS)

    Kupila, Juho

    2013-04-01

    Acid sulfate soils (ASS), also referred to as the "nastiest soils in the world", are soils that contain or have contained metal sulfides that oxidize under aerobic conditions and, subsequently, typically produce very severe acidity and metal pollution. In Finland, for example, the discharge of several metals to water courses from ASS is greater than that from the entire Finnish industry, and due to the acidity these metals largely occur in a soluble toxic form. In Europe, the largest occurrences of acid sulfate soils are located in Finland. It has been estimated that coverage of these harmful soils is approximately 1000 - 1500 km2 along the coastal areas of Finland. Sulfide-bearing fine-grained sediments were deposited in the sea between Finland and Sweden after the melting of the latest continental ice sheet, about 10,000 years ago. In places, the formation of such sediments is still going on today. The rapid isostatic land uplift (more than 200 m after the latest glacial period, currently up to 8 mm/year) after the retreat of the continental ice sheet has lifted these sediments above sea level. In Finland, systematic mapping and classification of acid sulfate soils started in 2009 with Geological Survey of Finland (GTK) as the leading partner, together with Åbo Akademi University and University of Helsinki. The definition of a risk classification of Finnish acid sulfate soils has been developed during the project. The observations, measurements and analyses have been used to produce e.g. probability maps of integrated catchment areas (at the scale 1:250 000), reports of the areas and guides for the identification of ASS and their environments. The main users of the results have been authorities at governmental, regional and local levels, organizations and actors in agriculture and forestry, peat production and earthwork companies and consultants concerned with soil and construction. The mapping project carried out by GTK is still in process and should be

  10. [Process and mechanism of plants in overcoming acid soil aluminum stress].

    PubMed

    Zhao, Tian-Long; Xie, Guang-Ning; Zhang, Xiao-Xia; Qiu, Lin-Quan; Wang, Na; Zhang, Su-Zhi

    2013-10-01

    Aluminum (Al) stress is one of the most important factors affecting the plant growth on acid soil. Currently, global soil acidification further intensifies the Al stress. Plants can detoxify Al via the chelation of ionic Al and organic acids to store the ionic Al in vacuoles and extrude it from roots. The Al extrusion is mainly performed by the membrane-localized anion channel proteins Al(3+)-activated malate transporter (ALMT) and multi-drug and toxin extrusion (MATE). The genes encoding ABC transporter and zinc-finger protein conferred plant Al tolerance have also been found. The identification of these Al-resistant genes makes it possible to increase the Al resistance of crop plants and enhance their production by the biological methods such as gene transformation and mark-associated breeding. The key problems needed to be solved and the possible directions in the researches of plant Al stress resistance were proposed.

  11. The combined effects of urea application and simulated acid rain on soil acidification and microbial community structure.

    PubMed

    Liu, Xingmei; Zhou, Jian; Li, Wanlu; Xu, Jianming; Brookes, Philip C

    2014-05-01

    Our aim was to test the effects of simulated acid rain (SAR) at different pHs, when applied to fertilized and unfertilized soils, on the leaching of soil cations (K, Ca, Mg, Na) and Al. Their effects on soil pH, exchangeable H(+) and Al(3+) and microbial community structure were also determined. A Paleudalfs soil was incubated for 30 days, with and without an initial application of urea (200 mg N kg(-1)soil) as nitrogen (N) fertilizer. The soil was held in columns and leached with SAR at three pH levels. Six treatments were tested: SAR of