16 CFR 802.21 - Acquisitions of voting securities not meeting or exceeding greater notification threshold (as...

Code of Federal Regulations, 2011 CFR

2011-01-01

... meeting or exceeding greater notification threshold (as adjusted). 802.21 Section 802.21 Commercial... meeting or exceeding greater notification threshold (as adjusted). (a) An acquisition of voting securities... of the acquiring person to meet or exceed a notification threshold (as adjusted) greater than the...

16 CFR 802.21 - Acquisitions of voting securities not meeting or exceeding greater notification threshold (as...

Code of Federal Regulations, 2010 CFR

2010-01-01

... meeting or exceeding greater notification threshold (as adjusted). 802.21 Section 802.21 Commercial... meeting or exceeding greater notification threshold (as adjusted). (a) An acquisition of voting securities... of the acquiring person to meet or exceed a notification threshold (as adjusted) greater than the...

Between-airport heterogeneity in air toxics emissions associated with individual cancer risk thresholds and population risks

PubMed Central

2009-01-01

Background Airports represent a complex source type of increasing importance contributing to air toxics risks. Comprehensive atmospheric dispersion models are beyond the scope of many applications, so it would be valuable to rapidly but accurately characterize the risk-relevant exposure implications of emissions at an airport. Methods In this study, we apply a high resolution atmospheric dispersion model (AERMOD) to 32 airports across the United States, focusing on benzene, 1,3-butadiene, and benzo [a]pyrene. We estimate the emission rates required at these airports to exceed a 10-6 lifetime cancer risk for the maximally exposed individual (emission thresholds) and estimate the total population risk at these emission rates. Results The emission thresholds vary by two orders of magnitude across airports, with variability predicted by proximity of populations to the airport and mixing height (R2 = 0.74–0.75 across pollutants). At these emission thresholds, the population risk within 50 km of the airport varies by two orders of magnitude across airports, driven by substantial heterogeneity in total population exposure per unit emissions that is related to population density and uncorrelated with emission thresholds. Conclusion Our findings indicate that site characteristics can be used to accurately predict maximum individual risk and total population risk at a given level of emissions, but that optimizing on one endpoint will be non-optimal for the other. PMID:19426510

48 CFR 636.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... for contracts not to exceed the simplified acquisition threshold. 636.602-5 Section 636.602-5 Federal... not to exceed the simplified acquisition threshold. The short selection process described in FAR 36.602-5 is authorized for use for contracts not expected to exceed the simplified acquisition threshold...

48 CFR 1336.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for contracts not to exceed the simplified acquisition threshold. 1336.602-5 Section 1336.602-5... for contracts not to exceed the simplified acquisition threshold. (a) In contracts not expected to exceed the simplified acquisition threshold, either or both of the short selection processes set out at...

Year-Round Monitoring of Contaminants in Neal and Rogers Creeks, Hood River Basin, Oregon, 2011-12, and Assessment of Risks to Salmonids.

PubMed

Hapke, Whitney B; Morace, Jennifer L; Nilsen, Elena B; Alvarez, David A; Masterson, Kevin

2016-01-01

Pesticide presence in streams is a potential threat to Endangered Species Act listed salmonids in the Hood River basin, Oregon, a primarily forested and agricultural basin. Two types of passive samplers, polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs), were simultaneously deployed at four sites in the basin during Mar. 2011-Mar. 2012 to measure the presence of pesticides, polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs). The year-round use of passive samplers is a novel approach and offers several new insights. Currently used pesticides and legacy contaminants, including many chlorinated pesticides and PBDEs, were present throughout the year in the basin's streams. PCBs were not detected. Time-weighted average water concentrations for the 2-month deployment periods were estimated from concentrations of chemicals measured in the passive samplers. Currently used pesticide concentrations peaked during spring and were detected beyond their seasons of expected use. Summed concentrations of legacy contaminants in Neal Creek were highest during July-Sept., the period with the lowest streamflows. Endosulfan was the only pesticide detected in passive samplers at concentrations exceeding Oregon or U.S. Environmental Protection Agency water-quality thresholds. A Sensitive Pesticide Toxicity Index (SPTI) was used to estimate the relative acute potential toxicity among sample mixtures. The acute potential toxicity of the detected mixtures was likely greater for invertebrates than for fish and for all samples in Neal Creek compared to Rogers Creek, but the indices appear to be low overall (<0.1). Endosulfans and pyrethroid insecticides were the largest contributors to the SPTIs for both sites. SPTIs of some discrete (grab) samples from the basin that were used for comparison exceeded 0.1 when some insecticides (azinphos methyl, chlorpyrifos, malathion) were detected at concentrations near or exceeding acute water-quality thresholds. Early life stages and adults of several sensitive fish species, including salmonids, are present in surface waters of the basin throughout the year, including during periods of peak estimated potential toxicity. Based on these data, direct toxicity to salmonids from in-stream pesticide exposure is unlikely, but indirect impacts (reduced fitness due to cumulative exposures or negative impacts to invertebrate prey populations) are unknown.

Year-round monitoring of contaminants in Neal and Rogers Creeks, Hood River Basin, Oregon, 2011-12, and assessment of risks to salmonids

USGS Publications Warehouse

Temple, Whitney B.; Morace, Jennifer L.; Nilsen, Elena B.; Alvarez, David; Masterson, Kevin

2016-01-01

Pesticide presence in streams is a potential threat to Endangered Species Act listed salmonids in the Hood River basin, Oregon, a primarily forested and agricultural basin. Two types of passive samplers, polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs), were simultaneously deployed at four sites in the basin during Mar. 2011–Mar. 2012 to measure the presence of pesticides, polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs). The year-round use of passive samplers is a novel approach and offers several new insights. Currently used pesticides and legacy contaminants, including many chlorinated pesticides and PBDEs, were present throughout the year in the basin’s streams. PCBs were not detected. Time-weighted average water concentrations for the 2-month deployment periods were estimated from concentrations of chemicals measured in the passive samplers. Currently used pesticide concentrations peaked during spring and were detected beyond their seasons of expected use. Summed concentrations of legacy contaminants in Neal Creek were highest during July–Sept., the period with the lowest streamflows. Endosulfan was the only pesticide detected in passive samplers at concentrations exceeding Oregon or U.S. Environmental Protection Agency water-quality thresholds. A Sensitive Pesticide Toxicity Index (SPTI) was used to estimate the relative acute potential toxicity among sample mixtures. The acute potential toxicity of the detected mixtures was likely greater for invertebrates than for fish and for all samples in Neal Creek compared to Rogers Creek, but the indices appear to be low overall (<0.1). Endosulfans and pyrethroid insecticides were the largest contributors to the SPTIs for both sites. SPTIs of some discrete (grab) samples from the basin that were used for comparison exceeded 0.1 when some insecticides (azinphos methyl, chlorpyrifos, malathion) were detected at concentrations near or exceeding acute water-quality thresholds. Early life stages and adults of several sensitive fish species, including salmonids, are present in surface waters of the basin throughout the year, including during periods of peak estimated potential toxicity. Based on these data, direct toxicity to salmonids from in-stream pesticide exposure is unlikely, but indirect impacts (reduced fitness due to cumulative exposures or negative impacts to invertebrate prey populations) are unknown.

Year-Round Monitoring of Contaminants in Neal and Rogers Creeks, Hood River Basin, Oregon, 2011-12, and Assessment of Risks to Salmonids

PubMed Central

Hapke, Whitney B.; Morace, Jennifer L.; Nilsen, Elena B.; Alvarez, David A.; Masterson, Kevin

2016-01-01

Pesticide presence in streams is a potential threat to Endangered Species Act listed salmonids in the Hood River basin, Oregon, a primarily forested and agricultural basin. Two types of passive samplers, polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs), were simultaneously deployed at four sites in the basin during Mar. 2011–Mar. 2012 to measure the presence of pesticides, polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs). The year-round use of passive samplers is a novel approach and offers several new insights. Currently used pesticides and legacy contaminants, including many chlorinated pesticides and PBDEs, were present throughout the year in the basin’s streams. PCBs were not detected. Time-weighted average water concentrations for the 2-month deployment periods were estimated from concentrations of chemicals measured in the passive samplers. Currently used pesticide concentrations peaked during spring and were detected beyond their seasons of expected use. Summed concentrations of legacy contaminants in Neal Creek were highest during July–Sept., the period with the lowest streamflows. Endosulfan was the only pesticide detected in passive samplers at concentrations exceeding Oregon or U.S. Environmental Protection Agency water-quality thresholds. A Sensitive Pesticide Toxicity Index (SPTI) was used to estimate the relative acute potential toxicity among sample mixtures. The acute potential toxicity of the detected mixtures was likely greater for invertebrates than for fish and for all samples in Neal Creek compared to Rogers Creek, but the indices appear to be low overall (<0.1). Endosulfans and pyrethroid insecticides were the largest contributors to the SPTIs for both sites. SPTIs of some discrete (grab) samples from the basin that were used for comparison exceeded 0.1 when some insecticides (azinphos methyl, chlorpyrifos, malathion) were detected at concentrations near or exceeding acute water-quality thresholds. Early life stages and adults of several sensitive fish species, including salmonids, are present in surface waters of the basin throughout the year, including during periods of peak estimated potential toxicity. Based on these data, direct toxicity to salmonids from in-stream pesticide exposure is unlikely, but indirect impacts (reduced fitness due to cumulative exposures or negative impacts to invertebrate prey populations) are unknown. PMID:27348521

48 CFR 836.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for contracts not to exceed the simplified acquisition threshold. 836.602-5 Section 836.602-5 Federal... contracts not to exceed the simplified acquisition threshold. Either of the procedures provided in FAR 36... simplified acquisition threshold. ...

High frequency of fumigants and other toxic gases in imported freight containers--an underestimated occupational and community health risk.

PubMed

Baur, Xaver; Poschadel, Bernd; Budnik, Lygia Therese

2010-03-01

Residues of pesticide fumigants and toxic industrial chemicals in freight containers represent a health hazard to employees and consumers, especially since freight containers are sealed for transport and distributed widely throughout the importing countries before being opened for unloading. We investigated 2113 freight containers arriving at the second largest container terminal in Europe, Hamburg, Germany, over a 10-week period in 2006. The countries of origin, type of contents and the pesticide fumigation history declared on labels attached to the container were recorded. We determined that 1478 (70%) containers were contaminated with toxic chemicals above chronic reference exposure levels; 761 (36%) even exceeded the higher acute reference exposure level thresholds. Benzene and/or formaldehyde contamination was 4-times greater than for fumigants. Our findings indicate a health risk for dockworkers, container unloaders and even end-consumers, especially as many of the cancerogenic or toxic gases elude subjective detection.

A method for defining down-wind evacuation areas for transportation accidents involving toxic propellant spills

NASA Technical Reports Server (NTRS)

Siewert, R. D.

1972-01-01

Evacuation areas for accidental spills of toxic propellants along rail and highway shipping routes are defined to help local authorities reduce risks to people from excessive vapor concentrations. These criteria along with other emergency information are shown in propellant spill cards. The evacuation areas are based on current best estimates of propellant evaporation rates from various areas of spill puddles. These rates are used together with a continuous point-source, bi-normal model of plume dispersion. The rate at which the toxic plume disperses is based on a neutral atmospheric condition. This condition, which results in slow plume dispersion, represents the widest range of weather parameters which could occur during the day and nighttime periods. Evacuation areas are defined by the ground level boundaries of the plume within which the concentrations exceed the toxic Threshold Limit Value (TLV) or in some cases the Emergency Exposure Limit (EEL).

Health-hazard evaluation determination report No. 75-181-287, Fibreboard Corporation, Stockton, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okawa, M.T.

1976-05-01

Employees in the Litho Department of the Fibreboard Corporation Plant in Stockton, California are not found to be exposed to toxic concentrations of dusting powders, but are exposed to airborne dust levels from the powders which exceed the State of California OSHA standard and the threshold limits for nuisance dust. Safety recommendations include servicing of exhaust ventilation systems regularly, vacuum cleaning instead of dry sweeping, and making NIOSH Certified Respirators available whenever needed.

16 CFR 801.20 - Acquisitions subsequent to exceeding threshold.

Code of Federal Regulations, 2010 CFR

2010-01-01

... threshold. 801.20 Section 801.20 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS... § 801.20 Acquisitions subsequent to exceeding threshold. Acquisitions meeting the criteria of section 7A... may have met or exceeded a notification threshold before the effective date of these rules; or (c) The...

16 CFR 801.20 - Acquisitions subsequent to exceeding threshold.

Code of Federal Regulations, 2011 CFR

2011-01-01

... threshold. 801.20 Section 801.20 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS... § 801.20 Acquisitions subsequent to exceeding threshold. Acquisitions meeting the criteria of section 7A... may have met or exceeded a notification threshold before the effective date of these rules; or (c) The...

16 CFR 801.20 - Acquisitions subsequent to exceeding threshold.

Code of Federal Regulations, 2012 CFR

2012-01-01

... threshold. 801.20 Section 801.20 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS... § 801.20 Acquisitions subsequent to exceeding threshold. Acquisitions meeting the criteria of section 7A... may have met or exceeded a notification threshold before the effective date of these rules; or (c) The...

An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Republican River Basin: 1997-1999.

PubMed

May, T W; Walther, M J; Petty, J D; Fairchild, J F; Lucero, J; Delvaux, M; Manring, J; Armbruster, M; Hartman, D

2001-11-01

The Republican River Basin of Colorado, Nebraska, and Kansas lies in a valley which contains Pierre Shale as part of its geological substrata. Selenium is an indigenous constituent in the shale and is readily leached into surrounding groundwater. The Basin is heavily irrigated through the pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water, sediment, benthic invertebrates, and/or fish were collected from 46 sites in the Basin and were analyzed for selenium to determine the potential for food-chain bioaccumulation, dietary toxicity, and reproductive effects of selenium in biota. Resulting selenium concentrations were compared to published guidelines or biological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 microg L(-1), which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3-5 microg L(-1), constituting a moderate hazard. Selenium concentrations in sediment indicated little to no hazard for selenium accumulation from sediments into the benthic food chain. Ninety-five percent of benthic invertebrates collected exhibited selenium concentrations exceeding 3 microg g(-1), a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 microg g(-1) selenium, indicating a high potential for toxicity and reproductive effects. However, examination of weight profiles of various species of collected individual fish suggested successful recruitment in spite of selenium concentrations that exceeded published biological effects thresholds for health and reproductive success. This finding suggested that universal application of published guidelines for selenium may be inappropriate or at least may need refinement for systems similar to the Republican River Basin. Additional research is needed to determine the true impact of selenium on fish and wildlife resources in the Basin.

Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

USGS Publications Warehouse

Hinck, J.E.; Schmitt, C.J.; Chojnacki, K.A.; Tillitt, D.E.

2009-01-01

Organochlorine chemical residues and elemental concentrations were measured in piscivorous and benthivorous fish at 111 sites from large U.S. river basins. Potential contaminant sources such as urban and agricultural runoff, industrial discharges, mine drainage, and irrigation varied among the sampling sites. Our objectives were to provide summary statistics for chemical contaminants and to determine if contaminant concentrations in the fish were a risk to wildlife that forage at these sites. Concentrations of dieldrin, total DDT, total PCBs, toxaphene, TCDD-EQ, cadmium, chromium, mercury, lead, selenium, and zinc exceeded toxicity thresholds to protect fish and piscivorous wildlife in samples from at least one site; most exceedences were for total PCBs, mercury, and zinc. Chemical concentrations in fish from the Mississippi River Basin exceeded the greatest number of toxicity thresholds. Screening level wildlife risk analysis models were developed for bald eagle and mink using no adverse effect levels (NOAELs), which were derived from adult dietary exposure or tissue concentration studies and based primarily on reproductive endpoints. No effect hazard concentrations (NEHC) were calculated by comparing the NOAEL to the food ingestion rate (dietary-based NOAEL) or biomagnification factor (tissue-based NOAEL) of each receptor. Piscivorous wildlife may be at risk from a contaminant if the measured concentration in fish exceeds the NEHC. Concentrations of most organochlorine residues and elemental contaminants represented no to low risk to bald eagle and mink at most sites. The risk associated with pentachloroanisole, aldrin, Dacthal, methoxychlor, mirex, and toxaphene was unknown because NOAELs for these contaminants were not available for bald eagle or mink. Risk differed among modeled species and sites. Our screening level analysis indicates that the greatest risk to piscivorous wildlife was from total DDT, total PCBs, TCDD-EQ, mercury, and selenium. Bald eagles were at greater risk to total DDT and total PCBs than mink, whereas risks of TCDD-EQ, mercury, and selenium were greater to mink than bald eagle. ?? Springer Science+Business Media B.V. 2008.

41 CFR 102-73.40 - What happens if the dollar value of the project exceeds the prospectus threshold?

Code of Federal Regulations, 2010 CFR

2010-07-01

... dollar value of the project exceeds the prospectus threshold? 102-73.40 Section 102-73.40 Public... § 102-73.40 What happens if the dollar value of the project exceeds the prospectus threshold? Projects... the prospectus threshold. To obtain this approval, the Administrator of General Services will transmit...

41 CFR 102-73.40 - What happens if the dollar value of the project exceeds the prospectus threshold?

Code of Federal Regulations, 2011 CFR

2011-01-01

... dollar value of the project exceeds the prospectus threshold? 102-73.40 Section 102-73.40 Public... § 102-73.40 What happens if the dollar value of the project exceeds the prospectus threshold? Projects... the prospectus threshold. To obtain this approval, the Administrator of General Services will transmit...

41 CFR 102-73.40 - What happens if the dollar value of the project exceeds the prospectus threshold?

Code of Federal Regulations, 2012 CFR

2012-01-01

... dollar value of the project exceeds the prospectus threshold? 102-73.40 Section 102-73.40 Public... § 102-73.40 What happens if the dollar value of the project exceeds the prospectus threshold? Projects... the prospectus threshold. To obtain this approval, the Administrator of General Services will transmit...

Teratogenic effects and monetary cost of selenium poisoning of fish in Lake Sutton, North Carolina

Treesearch

A. Dennis Lemly

2014-01-01

Selenium pollution from coal ash waste water was investigated in Lake Sutton, NC. This lake has been continuously used as a cooling pond for a coal-fired power plant since 1972. Historic and recent levels of contamination in fish tissues (14–105 µg Se/g dry weight in liver, 24–127 in eggs, 4–23 in muscle,7–38 in whole-body) exceeded toxic thresholds and teratogenic...

Water Quality of Camp Creek, Costello Creek, and Other Selected Streams on the South Side of Denali National Park and Preserve, Alaska

USGS Publications Warehouse

Brabets, Timothy P.; Whitman, Matthew S.

2002-01-01

The Camp and Costello Creek watersheds are located on the south side of Denali National Park and Preserve. The Dunkle Mine, an abandoned coal mine, is located near the mouth of Camp Creek. Due to concern about runoff from the mine and its possible effects on the water quality and aquatic habitat of Camp Creek and its receiving stream, Costello Creek, these two streams were studied during the summer runoff months (June to September) in 1999 and 2000 as part of a cooperative study with the National Park Service. Since the south side of Denali National Park and Preserve is part of the U.S. Geological Survey?s National Water-Quality Assessment Cook Inlet Basin study unit, an additional part of this study included analysis of existing water-quality data at 23 sites located throughout the south side of Denali National Park and Preserve to compare with the water quality of Camp and Costello Creeks and to obtain a broader understanding of the water quality in this area of the Cook Inlet Basin. Analysis of water column, bed sediment, fish, invertebrate, and algae data indicate no effects on the water quality of Camp Creek from the Dunkle Mine. Although several organic compounds were found in the streambed of Camp Creek, all concentrations were below recommended levels for aquatic life and most of the concentrations were below the minimum reporting level of 50 ?g/kg. Trace element concentrations of arsenic, chromium, and nickel in the bed sediments of Camp Creek exceeded threshold effect concentrations (TEC), but concentrations of these trace elements were also exceeded in streambed sediments of Costello Creek above Camp Creek. Since the percent organic carbon in Camp Creek is relatively high, the toxicity quotient of 0.55 is only slightly above the threshold value of 0.5. Costello Creek has a relatively low organic carbon content and has a higher toxicity quotient of 1.19. Analysis of the water-quality data for other streams located in the south side of Denali National Park and Preserve indicate similarities to Camp Creek and Costello Creek. Most of the streams are calcium bicarbonate/calcium bicarbonate-sulfate type water with the exception of two streams that are calcium sulfate and magnesium sulfate type water. Trace element concentrations of arsenic, chromium, and nickel in the bed sediments of 9 streams exceeded the TEC or the probable effect concentration (PEC). Seven streams exceeded the threshold value of the toxicity quotient. Analysis of trace element concentrations in bed sediment and basin characteristics for 16 watersheds by cluster and discriminant analysis techniques indicated that the watersheds could be separated into two groups based on their basin characteristics.

Relationships among exceedences of metals criteria, the results of ambient bioassays, and community metrics in mining-impacted streams.

PubMed

Griffith, Michael B; Lazorchak, James M; Herlihy, Alan T

2004-07-01

If bioassessments are to help diagnose the specific environmental stressors affecting streams, a better understanding is needed of the relationships between community metrics and ambient criteria or ambient bioassays. However, this relationship is not simple, because metrics assess responses at the community level of biological organization, while ambient criteria and ambient bioassays assess or are based on responses at the individual level. For metals, the relationship is further complicated by the influence of other chemical variables, such as hardness, on their bioavailability and toxicity. In 1993 and 1994, U.S. Environmental Protection Agency (U.S. EPA) conducted a Regional Environmental Monitoring and Assessment Program (REMAP) survey on wadeable streams in Colorado's (USA) Southern Rockies Ecoregion. In this ecoregion, mining over the past century has resulted in metals contamination of streams. The surveys collected data on fish and macroinvertebrate assemblages, physical habitat, and sediment and water chemistry and toxicity. These data provide a framework for assessing diagnostic community metrics for specific environmental stressors. We characterized streams as metals-affected based on exceedence of hardness-adjusted criteria for cadmium, copper, lead, and zinc in water; on water toxicity tests (48-h Pimephales promelas and Ceriodaphnia dubia survival); on exceedence of sediment threshold effect levels (TELs); or on sediment toxicity tests (7-d Hyalella azteca survival and growth). Macroinvertebrate and fish metrics were compared among affected and unaffected sites to identify metrics sensitive to metals. Several macroinvertebrate metrics, particularly richness metrics, were less in affected streams, while other metrics were not. This is a function of the sensitivity of the individual metrics to metals effects. Fish metrics were less sensitive to metals because of the low diversity of fish in these streams.

Development and application of freshwater sediment-toxicity benchmarks for currently used pesticides

USGS Publications Warehouse

Nowell, Lisa H.; Norman, Julia E.; Ingersoll, Christopher G.; Moran, Patrick W.

2016-01-01

Sediment-toxicity benchmarks are needed to interpret the biological significance of currently used pesticides detected in whole sediments. Two types of freshwater sediment benchmarks for pesticides were developed using spiked-sediment bioassay (SSB) data from the literature. These benchmarks can be used to interpret sediment-toxicity data or to assess the potential toxicity of pesticides in whole sediment. The Likely Effect Benchmark (LEB) defines a pesticide concentration in whole sediment above which there is a high probability of adverse effects on benthic invertebrates, and the Threshold Effect Benchmark (TEB) defines a concentration below which adverse effects are unlikely. For compounds without available SSBs, benchmarks were estimated using equilibrium partitioning (EqP). When a sediment sample contains a pesticide mixture, benchmark quotients can be summed for all detected pesticides to produce an indicator of potential toxicity for that mixture. Benchmarks were developed for 48 pesticide compounds using SSB data and 81 compounds using the EqP approach. In an example application, data for pesticides measured in sediment from 197 streams across the United States were evaluated using these benchmarks, and compared to measured toxicity from whole-sediment toxicity tests conducted with the amphipod Hyalella azteca (28-d exposures) and the midge Chironomus dilutus (10-d exposures). Amphipod survival, weight, and biomass were significantly and inversely related to summed benchmark quotients, whereas midge survival, weight, and biomass showed no relationship to benchmarks. Samples with LEB exceedances were rare (n = 3), but all were toxic to amphipods (i.e., significantly different from control). Significant toxicity to amphipods was observed for 72% of samples exceeding one or more TEBs, compared to 18% of samples below all TEBs. Factors affecting toxicity below TEBs may include the presence of contaminants other than pesticides, physical/chemical characteristics of sediment, and uncertainty in TEB values. Additional evaluations of benchmarks in relation to sediment chemistry and toxicity are ongoing.

Influence of a Brazilian sewage outfall on the toxicity and contamination of adjacent sediments

USGS Publications Warehouse

Abessa, D.M.S.; Carr, R.S.; Rachid, B.R.F.; Sousa, E.C.P.M.; Hortelani, M.A.; Sarkis, J.E.

2005-01-01

The submarine sewage outfall of Santos (SSOS) is situated in the Santos Bay (São Paulo, Brazil) and is potentially a significant source of contaminants to the adjacent marine ecosystem. The present study aimed to assess the influence of SSOS on the sediment toxicity and contamination at Santos Bay. At the disposal site, sediments tended to be finer, organically richer and exhibited higher levels of surfactants and metals, sometimes exceeding the “Threshold Effect Level” values. The SSOS influence was more evident toward the East, where the sediments exhibited higher levels of TOC, total S and metals during the summer 2000 sampling campaign. Sediment toxicity to amphipods was consistently detected in four of the five stations studied. Amphipod survival tended to correlate negatively to Hg, total N and % mud. This work provides evidence that the SSOS discharge affects the quality of sediments from Santos Bay, and that control procedures are warranted.

An F1-extended one-generation reproductive toxicity study in Crl:CD(SD) rats with 2,4-dichlorophenoxyacetic acid.

PubMed

Marty, Mary Sue; Neal, Barbara H; Zablotny, Carol L; Yano, Barry L; Andrus, Amanda K; Woolhiser, Michael R; Boverhof, Darrell R; Saghir, Shakil A; Perala, Adam W; Passage, Julie K; Lawson, Marie A; Bus, James S; Lamb, James C; Hammond, Larry

2013-12-01

2,4-Dichlorophenoxyacetic acid (2,4-D) was assessed for systemic toxicity, reproductive toxicity, developmental neurotoxicity (DNT), developmental immunotoxicity (DIT), and endocrine toxicity. CD rats (27/sex/dose) were exposed to 0, 100, 300, 600 (female), or 800 (male) ppm 2,4-D in diet. Nonlinear toxicokinetic behavior was shown at high doses; the renal clearance saturation threshold for 2,4-D was exceeded markedly in females and slightly exceeded in males. Exposure was 4 weeks premating, 7 weeks postmating for P1 males and through lactation for P1 females. F1 offspring were examined for survival and development, and at weaning, pups were divided in cohorts, by sex and dose, and by systemic toxicity (10), DNT (10), DIT (20), and reproductive toxicity (≥ 23). Remaining weanlings were evaluated for systemic toxicity and neuropathology (10-12). Body weight decreased during lactation in high-dose P1 females and in F1 pups. Kidney was the primary target organ, with slight degeneration of proximal convoluted tubules observed in high-dose P1 males and in high-dose F1 males and females. A slight intergenerational difference in kidney toxicity was attributed to increased intake of 2,4-D in F1 offspring. Decreased weanling testes weights and delayed preputial separation in F1 males were attributed to decreased body weights. Endocrine-related effects were limited to slight thyroid hormone changes and adaptive histopathology in high-dose GD 17 dams seen only at a nonlinear toxicokinetic dose. 2,4-D did not cause reproductive toxicity, DNT, or DIT. The "No Observed Adverse Effect Level" for systemic toxicity was 300 ppm in both males (16.6 mg/kg/day) and females (20.6 mg/kg/day), which is approximately 6700- to 93 000-fold higher than that reported for 2,4-D exposures in human biomonitoring studies.

An F1-Extended One-Generation Reproductive Toxicity Study in Crl:CD(SD) Rats With 2,4-Dichlorophenoxyacetic Acid

PubMed Central

Marty, Mary Sue

2013-01-01

2,4-Dichlorophenoxyacetic acid (2,4-D) was assessed for systemic toxicity, reproductive toxicity, developmental neurotoxicity (DNT), developmental immunotoxicity (DIT), and endocrine toxicity. CD rats (27/sex/dose) were exposed to 0, 100, 300, 600 (female), or 800 (male) ppm 2,4-D in diet. Nonlinear toxicokinetic behavior was shown at high doses; the renal clearance saturation threshold for 2,4-D was exceeded markedly in females and slightly exceeded in males. Exposure was 4 weeks premating, 7 weeks postmating for P1 males and through lactation for P1 females. F1 offspring were examined for survival and development, and at weaning, pups were divided in cohorts, by sex and dose, and by systemic toxicity (10), DNT (10), DIT (20), and reproductive toxicity (≥ 23). Remaining weanlings were evaluated for systemic toxicity and neuropathology (10–12). Body weight decreased during lactation in high-dose P1 females and in F1 pups. Kidney was the primary target organ, with slight degeneration of proximal convoluted tubules observed in high-dose P1 males and in high-dose F1 males and females. A slight intergenerational difference in kidney toxicity was attributed to increased intake of 2,4-D in F1 offspring. Decreased weanling testes weights and delayed preputial separation in F1 males were attributed to decreased body weights. Endocrine-related effects were limited to slight thyroid hormone changes and adaptive histopathology in high-dose GD 17 dams seen only at a nonlinear toxicokinetic dose. 2,4-D did not cause reproductive toxicity, DNT, or DIT. The “No Observed Adverse Effect Level” for systemic toxicity was 300 ppm in both males (16.6mg/kg/day) and females (20.6mg/kg/day), which is approximately 6700- to 93 000-fold higher than that reported for 2,4-D exposures in human biomonitoring studies. PMID:24072463

A New Approach in Applying Systems Engineering Tools and Analysis to Determine Hepatocyte Toxicogenomics Risk Levels to Human Health.

PubMed

Gigrich, James; Sarkani, Shahryar; Holzer, Thomas

2017-03-01

There is an increasing backlog of potentially toxic compounds that cannot be evaluated with current animal-based approaches in a cost-effective and expeditious manner, thus putting human health at risk. Extrapolation of animal-based test results for human risk assessment often leads to different physiological outcomes. This article introduces the use of quantitative tools and methods from systems engineering to evaluate the risk of toxic compounds by the analysis of the amount of stress that human hepatocytes undergo in vitro when metabolizing GW7647 1 over extended times and concentrations. Hepatocytes are exceedingly connected systems that make it challenging to understand the highly varied dimensional genomics data to determine risk of exposure. Gene expression data of peroxisome proliferator-activated receptor-α (PPARα) 2 binding was measured over multiple concentrations and varied times of GW7647 exposure and leveraging mahalanombis distance to establish toxicity threshold risk levels. The application of these novel systems engineering tools provides new insight into the intricate workings of human hepatocytes to determine risk threshold levels from exposure. This approach is beneficial to decision makers and scientists, and it can help reduce the backlog of untested chemical compounds due to the high cost and inefficiency of animal-based models.

Dose-mortality assessment upon reuse and recycling of industrial sludge.

PubMed

Lin, Kae-Long; Chen, Bor-Yann

2007-09-05

This study provides a novel attempt to put forward, in general toxicological terms, quantitative ranking of toxicity of various sources of sludge for possible reusability in further applications. The high leaching concentrations of copper in printed circuit board (PCB) sludge and chromium in leather sludge apparently exceeded current Taiwan's EPA regulatory thresholds and should be classified as hazardous wastes. Dose-mortality analysis indicated that the toxicity ranking of different sources of sludge was PCB sludge>CaF(2) sludge>leather sludge. PCB sludge was also confirmed as a hazardous waste since the toxicity potency of PCB sludge was nearly identical to CdCl(2). However, leather sludge seemed to be much less toxic than as anticipated, perhaps due to a significant decrease of toxic species bioavailable in the aqueous phase to the reporter bacterium Escherichia coli DH5alpha. For possible reusability of sludge, maximum concentrations allowable to be considered "safe" (ca. EC(100)/100) were 9.68, 42.1 and 176 mgL(-1) for CaF(2) sludge, PCB sludge and leather sludge, respectively.

Species sensitivity distribution evaluation for selenium in fish eggs: considerations for development of a Canadian tissue-based guideline.

PubMed

DeForest, David K; Gilron, Guy; Armstrong, Sarah A; Robertson, Erin L

2012-01-01

A freshwater Se guideline was developed for consideration based on concentrations in fish eggs or ovaries, with a focus on Canadian species, following the Canadian Council of Ministers of the Environment protocol for developing guideline values. When sufficient toxicity data are available, the protocol recommends deriving guidelines as the 5th percentile of the species sensitivity distribution (SSD). When toxicity data are limited, the protocol recommends a lowest value approach, where the lowest toxicity threshold is divided by a safety factor (e.g., 10). On the basis of a comprehensive review of the current literature and an assessment of the data therein, there are sufficient egg and ovary Se data available for freshwater fish to develop an SSD. For most fish species, Se EC10 values (10% effect concentrations) could be derived, but for some species, only no-observed-effect concentrations and/or lowest-observed-effect concentrations could be identified. The 5th percentile egg and ovary Se concentrations from the SSD were consistently 20 µg/g dry weight (dw) for the best-fitting distributions. In contrast, the lowest value approach using a safety factor of 10 would result in a Se egg and ovary guideline of 2 µg/g dw, which is unrealistically conservative, as this falls within the range of egg and ovary Se concentrations in laboratory control fish and fish collected from reference sites. An egg and ovary Se guideline of 20 µg/g dw should be considered a conservative, broadly applicable guideline, as no species mean toxicity thresholds lower than this value have been identified to date. When concentrations exceed this guideline, site-specific studies with local fish species, conducted using a risk-based approach, may result in higher egg and ovary Se toxicity thresholds. Copyright © 2011 SETAC.

48 CFR 736.602-5 - Short selection process for procurements not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Short selection process for procurements not to exceed the simplified acquisition threshold. 736.602-5 Section 736.602-5... selection process for procurements not to exceed the simplified acquisition threshold. References to FAR 36...

48 CFR 436.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 436.602-5 Section 436.602-5 Federal... to exceed the simplified acquisition threshold. The HCA may include either or both procedures in FAR...

Expected effects of residual chlorine and nitrogen in sewage effluent on an estuarine pelagic ecosystem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hattis, D.; Lemerise, A.; Ratick, S.

1995-12-31

The authors used physical, toxicological, and system dynamic modeling tools to estimate the probable ecological effects caused by residual chlorine and nitrogen in sewage effluent discharged into Greenwich Cove, RI, USA. An energy systems model of the pelagic ecosystem in Narragansett Bay was developed and adapted for use in Greenwich Cove. This model allowed them to assess the indirect effects on organisms in the food web that result from a direct toxic effect on a given organism. Indirect food web mediated effects were the primary mode of loss for bluefish, but not for menhaden. The authors chose gross primary production,more » the flux of carbon to the benthos, fish out-migration, and fish harvest as outcome variables indicative of different valuable ecosystem functions. Organism responses were modeled using an assumption that lethal toxic responses occur as individual organism thresholds are exceeded, and that in general thresholds are lognormally distributed in a population of mixed individuals. They performed sensitivity analyses to assess the implications of different plausible values for the probit slopes used in the model. The putative toxic damage repair rate, combined with estimates of the exposure variability for each species, determined the averaging time that was likely to be most important in producing toxicity. Temperature was an important external factor in the physical, toxicological, and ecological models. These three models can be integrated into a single model applicable to other locations and stressors given the availability of appropriate data.« less

Detection of short-term changes in vegetation cover by use of LANDSAT imagery. [Arizona

NASA Technical Reports Server (NTRS)

Turner, R. M. (Principal Investigator); Wiseman, F. M.

1975-01-01

The author has identified the following significant results. By using a constant band 6 to band 5 radiance ratio of 1.25, the changing pattern of areas of relatively dense vegetation cover was detected for the semiarid region in the vicinity of Tucson, Arizona. Electronically produced binary thematic masks were used to map areas with dense vegetation. The foliar cover threshold represented by the ratio was not accurately determined but field measurements show that the threshold lies in the range of 10 to 25 percent foliage cover. Montana evergreen forests with constant dense cover were correctly shown to exceed the threshold on all dates. The summer active grassland exceeded the threshold in the summer unless rainfall was insufficient. Desert areas exceeded the threshold during the spring of 1973 following heavy rains; the same areas during the rainless spring of 1974 did not exceed threshold. Irrigated fields, parks, golf courses, and riparian communities were among the habitats most frequently surpassing the threshold.

Estimation of Potential Population Level Effects of Contaminants on Wildlife

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loar, J.M.

2001-06-11

The objective of this project is to provide DOE with improved methods to assess risks from contaminants to wildlife populations. The current approach for wildlife risk assessment consists of comparison of contaminant exposure estimates for individual animals to literature-derived toxicity test endpoints. These test endpoints are assumed to estimate thresholds for population-level effects. Moreover, species sensitivities to contaminants is one of several criteria to be considered when selecting assessment endpoints (EPA 1997 and 1998), yet data on the sensitivities of many birds and mammals are lacking. The uncertainties associated with this approach are considerable. First, because toxicity data are notmore » available for most potential wildlife endpoint species, extrapolation of toxicity data from test species to the species of interest is required. There is no consensus on the most appropriate extrapolation method. Second, toxicity data are represented as statistical measures (e.g., NOAEL s or LOAELs) that provide no information on the nature or magnitude of effects. The level of effect is an artifact of the replication and dosing regime employed, and does not indicate how effects might increase with increasing exposure. Consequently, slight exceedance of a LOAEL is not distinguished from greatly exceeding it. Third, the relationship of toxic effects on individuals to effects on populations is poorly estimated by existing methods. It is assumed that if the exposure of individuals exceeds levels associated with impaired reproduction, then population level effects are likely. Uncertainty associated with this assumption is large because depending on the reproductive strategy of a given species, comparable levels of reproductive impairment may result in dramatically different population-level responses. This project included several tasks to address these problems: (1) investigation of the validity of the current allometric scaling approach for interspecies extrapolation an d development of new scaling models; (2) development of dose-response models for toxicity data presented in the literature; and (3) development of matrix-based population models that were coupled with dose-response models to provide realistic estimation of population-level effects for individual responses.« less

Influence of rice field agrochemicals on the ecological status of a tropical stream.

PubMed

Rasmussen, Jes Jessen; Reiler, Emilie Marie; Carazo, Elizabeth; Matarrita, Jessie; Muñoz, Alejandro; Cedergreen, Nina

2016-01-15

Many tropical countries contain a high density of protected ecosystems, and these may often be bordered by intensive agricultural systems. We investigated the chemical and ecological status of a stream connecting an area with conventional rice production and a downstream protected nature reserve; Mata Redonda. Three sites were sampled: 1) an upstream control, 2) in the rice production area and 3) a downstream site in Mata Redonda. We sampled benthic macroinvertebrates and pesticides in water and sediments along with supporting physical and chemical data. Pesticide concentrations in water exceeded current safety thresholds at sites 2 and 3, especially during the rainy season, and sediment associated pesticide concentrations exceeded current safety thresholds in three of six samples. Importantly, the highest predicted pesticide toxicity in sediments was observed at site 3 in the Mata Redonda confirming that the nature reserve received critical levels of pesticide pollution from upstream sections. The currently used macroinvertebrate index in Costa Rica (BMWP-CR) and an adjusted version of the SPecies At Risk index (SPEAR) were not significantly correlated to any measure of anthropogenic stress, but the Average Score Per Taxon (ASPT) index was significantly correlated with the predicted pesticide toxicity (sumTUD.magna), oxygen concentrations and substrate composition. Our results suggest that pesticide pollution was likely involved in the impairment of the ecological status of the sampling sites, including site 3 in Mata Redonda. Based on our results, we give guidance to biomonitoring in Costa Rica and call for increased focus on pesticide transport from agricultural regions to protected areas. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of neurotoxic effects of mercury in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) from the Canadian Arctic.

PubMed

Krey, Anke; Ostertag, Sonja K; Chan, Hing Man

2015-03-15

Marine mammals are indicator species of the Arctic ecosystem and an integral component of the traditional Inuit diet. The potential neurotoxic effects of increased mercury (Hg) in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) are not clear. We assessed the risk of Hg-associated neurotoxicity to these species by comparing their brain Hg concentrations with threshold concentrations for toxic endpoints detected in laboratory animals and field observations: clinical symptoms (>6.75 mg/kg wet weight (ww)), neuropathological signs (>4 mg/kg ww), neurochemical changes (>0.4 mg/kg ww), and neurobehavioral changes (>0.1mg/kg ww). The total Hg (THg) concentrations in the cerebellum and frontal lobe of ringed seals and polar bears were <0.5mg/kg ww, whereas the average concentration in beluga whale brain was >3mg/kg ww. Our results suggest that brain THg levels in polar bears are below levels that induce neurobehavioral effects as reported in the literature, while THg concentrations in ringed seals are within the range that elicit neurobehavioral effects and individual ringed seals exceed the threshold for neurochemical changes. The relatively high THg concentration in beluga whales exceeds all of the neurotoxicity thresholds assessed. High brain selenium (Se):Hg molar ratios were observed in all three species, suggesting that Se could protect the animals from Hg-associated neurotoxicity. This assessment was limited by several factors that influence neurotoxic effects in animals, including: animal species; form of Hg in the brain; and interactions with modifiers of Hg-associated toxicity, such as Se. Comparing brain Hg concentrations in wildlife with concentrations of appropriate laboratory studies can be used as a tool for risk characterization of the neurotoxic effects of Hg in Arctic marine mammals. Copyright © 2014 Elsevier B.V. All rights reserved.

Contaminants in fish tissue from US lakes and reservoirs: A ...

EPA Pesticide Factsheets

An unequal probability design was used to develop national estimates for 268 persistent, bioaccumulative, and toxic chemicals in fish tissue from lakes and reservoirs of the conterminous United States (excluding the Laurentian Great Lakes and Great Salt Lake). Predator (fillet) and bottom-dweller (whole-body) composites were collected from 500 lakes selected randomly from the target population of 147,343 lakes in the lower 48 states. Each of these composite types comprised nationally representative samples whose results were extrapolated to the sampled population of an estimated 76,559 lakes for predators and 46,190 lakes for bottom dwellers. Mercury and PCBs were detected in all fish samples. Dioxins and furans were detected in 81% and 99% of predator and bottom-dweller samples, respectively. Cumulative frequency distributions showed that mercury concentrations exceeded the EPA 300 ppb mercury fish tissue criterion at nearly half of the lakes in the sampled population. Total PCB concentrations exceeded a 12 ppb human health risk-based consumption limit at nearly 17% of lakes, and dioxins and furans exceeded a 0.15 ppt (toxic equivalent or TEQ) risk-based threshold at nearly 8% of lakes in the sampled population. In contrast, 43 target chemicals were not detected in any samples. No detections were reported for nine organophosphate pesticides, one PCB congener, 16 polycyclic aromatic hydrocarbons, or 17 other semivolatile organic chemicals. An unequal prob

Contaminants in fish tissue from US lakes and reservoirs: a national probabilistic study.

PubMed

Stahl, Leanne L; Snyder, Blaine D; Olsen, Anthony R; Pitt, Jennifer L

2009-03-01

An unequal probability design was used to develop national estimates for 268 persistent, bioaccumulative, and toxic chemicals in fish tissue from lakes and reservoirs of the conterminous United States (excluding the Laurentian Great Lakes and Great Salt Lake). Predator (fillet) and bottom-dweller (whole body) composites were collected from 500 lakes selected randomly from the target population of 147,343 lakes in the lower 48 states. Each of these composite types comprised nationally representative samples whose results were extrapolated to the sampled population of an estimated 76,559 lakes for predators and 46,190 lakes for bottom dwellers. Mercury and PCBs were detected in all fish samples. Dioxins and furans were detected in 81% and 99% of predator and bottom-dweller samples, respectively. Cumulative frequency distributions showed that mercury concentrations exceeded the EPA 300 ppb mercury fish tissue criterion at nearly half of the lakes in the sampled population. Total PCB concentrations exceeded a 12 ppb human health risk-based consumption limit at nearly 17% of lakes, and dioxins and furans exceeded a 0.15 ppt (toxic equivalent or TEQ) risk-based threshold at nearly 8% of lakes in the sampled population. In contrast, 43 target chemicals were not detected in any samples. No detections were reported for nine organophosphate pesticides, one PCB congener, 16 polycyclic aromatic hydrocarbons, or 17 other semivolatile organic chemicals.

Poorly soluble particulates: searching for a unifying denominator of nanoparticles and fine particles for DNEL estimation.

PubMed

Pauluhn, Jürgen

2011-01-11

Under the new European chemicals regulation, REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) a Derived No-Effect Level (DNEL), i.e., the level of exposure above which humans should not be exposed, is defined. The focus of this paper is to develop a weight-of-evidence-based DNEL-approach for inhaled poorly soluble particles. Despite the common mode of action of inhaled insoluble, spherical particulate matter (PM), a unifying, most appropriate metric conferring pulmonary biopersistence and toxicity has yet not been demonstrated. Nonetheless, there is compelling evidence from repeated rat inhalation exposure studies suggesting that the particle displacement volume is the most prominent unifying denominator linking the pulmonary retained dose with toxicity. Procedures were developed to analyze and model the pulmonary toxicokinetics from short-term to long-term exposure. Six different types of poorly soluble nano- to submicron PMs were compared: ultrafine and pigmentary TiO₂, synthetic iron oxide (Fe₃O₄, magnetite), two aluminum oxyhydroxides (AlOOH, Boehmite) with primary isometric particles approximately of either 10 or 40 nm, and MWCNT. The specific agglomerate densities of these materials ranged from 0.1 g/cm³ (MWCNT) to 5 g/cm³ (Fe₃O₄). Along with all PM, due to their long retention half-times and associated biopersistence in the lung, even short-term inhalation studies may require postexposure periods of at least 3 months to reveal PM-specific dispositional and toxicological characteristics. This analysis provides strong evidence that pulmonary toxicity (sustained inflammation) is dependent on the volume-based cumulative lung exposure dose. Lung toxicity, evidenced by PMN in BAL occurred at lung doses exceeding 10-times the overload threshold. Furthermore, the conclusion is supported that repeated inhalation studies on rats should utilize an experimental window of cumulative volume loads of respirable PM in the range of 1 μl/lung (no-adverse-effect range); however, not exceeding ≈10 μl/lung that would lead to retention half-times increasing 1 year. This can be targeted best by computational toxicology, i.e., the modeling of particle deposition and lung retention biokinetics during the exposure and recovery periods. Inhalation studies exceeding that threshold volume may lead to meaningless findings difficult to extrapolate to any real-life scenario. In summary, this analysis supports a volume-based generic mass concentration of 0.5 μl PM(respirable)/m³ x agglomerate density, independent on nano- or submicron-sized properties, as a generic no-adverse effect level in both rats and humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Heavy metal in sediments of Ziya River in northern China: distribution, potential risks, and source apportionment.

PubMed

Zhu, Xiaolei; Shan, Baoqing; Tang, Wenzhong

2016-12-01

The concentration partitioning between the sediment particle and the interstitial water phase plays an important role in controlling the toxicity of heavy metals in aquatic systems. The aim of this study was to assess the sediment quality in a polluted area of the Ziya River, Northern China. The contamination potential and bioavailability of six metals were determined from the concentrations of total metals and the bioavailable fractions. The results showed that the concentrations of Cr, Cu, Ni, Zn, and Pb exceeded the probable effect concentration at several sites. The high geoaccumulation indices showed that the sediments were seriously contaminated by Cd. The ratio of acid-volatile sulfide (AVS) to simultaneously extracted metal (SEM) was higher than 1, which indicated that the availability of metals in sediments was low. The risk assessment of interstitial waters confirmed that there was little chance of release of metals associated with acid-volatile sulfide into the water column. Values of the interstitial water criteria toxicity unit indicated that none of the concentrations of the studied metals exceeded the corresponding water quality thresholds of the US Environmental Protection Agency. Positive matrix factorization showed that the major sources of metals were related to anthropogenic activities. Further, if assessments are based on total heavy metal concentrations, the toxicity of heavy metals in sediment may be overestimated.

Ecotoxicological assessment of bluegill sunfish inhabiting a selenium-enriched fly ash stream

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reash, R.J.; Lohner, T.W.; Wood, K.V.

1999-07-01

Little Scary Creek (LSC), a 2nd-order tributary of the Kanawha River in West Virginia, receives treated fly ash produced during coal combustion. Selenium and other trace metals were determined in water column and sediment samples, caddisflies, and bluegill sunfish liver and gonads during 1995--96 to estimate pathways of selenium exposure and assess the likelihood of toxic effects. Selenium levels in LSC water and sediment samples, and in caddisflies were elevated compared to reference sites. Mean dry weight selenium concentrations in bluegill liver, ovary, and tested tissue equaled or exceeded published toxic thresholds. Other trace metals were significantly higher in LSCmore » bluegill. Leukopenia, elevated serum salts, and lowered liver weight were found in LSC bluegill. Fewer older bluegill were found in LSC. Sunfish in LSC are experiencing various kinds of sublethal stress, presumably due to metals exposure. However, major toxic effects that would be predicted to occur based on tissue selenium levels (complete reproductive failure or mortality) have not been observed in this population.« less

Tricresyl phosphate and the aerotoxic syndrome of flight crew members--current gaps in knowledge.

PubMed

de Boer, Jacob; Antelo, Angel; van der Veen, Ike; Brandsma, Sicco; Lammertse, Nienke

2015-01-01

Tricresyl phosphate (TCP), and in particular its tri-ortho substituted isomer (o,o,o-TCP), has been frequently used in aircraft engine oil. Bleed air, provided to the flight deck and cabin can contain traces of TCP. TCP can cause neurotoxic effects in humans. Regularly, airline pilots complain about loss of memory, headaches, dizziness, tunnel vision and other neurotoxic effects. The concentrations of TCP reported in flight deck air (max. ca. 50-100 ng m(-3) total TCP) do not exceed provisional toxicity thresholds. These thresholds, however, contain a very high uncertainty and need further underpinning. The many non-detects and relatively low TCP concentrations reported suggest that TCP on its own is not likely to be responsible for the reported health problems of pilots. Specific conditions in air planes and other toxic compounds present in bleed air, whether or not in combination with TCP, may be responsible for the reported neurotoxic syndromes. Sensitivity of individuals seems to be an important factor as well. The clinical signs observed with a selected group of pilots are serious enough to call for further elucidation of this issue. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Insignificance of Thresholds in Environmental Impact Assessment: An Illustrative Case Study in Canada

NASA Astrophysics Data System (ADS)

Murray, Cathryn Clarke; Wong, Janson; Singh, Gerald G.; Mach, Megan; Lerner, Jackie; Ranieri, Bernardo; Peterson St-Laurent, Guillaume; Guimaraes, Alice; Chan, Kai M. A.

2018-06-01

Environmental assessment is the process that decision-makers rely on to predict, evaluate, and prevent biophysical, social, and economic impacts of potential project developments. The determination of significance in environmental assessment is central to environmental management in many nations. We reviewed ten recent environmental impact assessments from British Columbia, Canada and systematically reviewed and scored significance determination and the approaches used by assessors, the use of thresholds in significance determination, threshold exceedances, and the outcomes. Findings of significant impacts were exceedingly rare and practitioners used a combination of significance determination approaches, most commonly relying upon reasoned argumentation. Quantitative thresholds were rarely employed, with less than 10% of the valued components evaluated using thresholds. Even where quantitative thresholds for significance were exceeded, in every case practitioners used a variety of rationales to demote negative impacts to non-significance. These reasons include combinations of scale (temporal and spatial) of impacts, an already exceeded baseline, model uncertainty and/or substituting less stringent thresholds. Governments and agencies can better protect resources by requiring clear and defensible significance determinations, by making government-defined thresholds legally enforceable and accountable, and by requiring or encouraging significance determination through inclusive and collaborative approaches.

Occurrence and concentrations of selected trace elements, halogenated organic compounds, and polycyclic aromatic hydrocarbons in streambed sediments and results of water-toxicity testing in Westside Creeks and the San Antonio River, San Antonio, Texas, 2014

USGS Publications Warehouse

Crow, Cassi L.; Wilson, Jennifer T.; Kunz, James L.

2016-12-01

Sediment samples and samples for water-toxicity testing were collected during 2014 from several streams in San Antonio, Texas, known locally as the Westside Creeks (Alazán, Apache, Martínez, and San Pedro Creeks) and from the San Antonio River. Samples were collected during base flow and after periods of stormwater runoff (poststorm conditions) to determine baseline sediment- and water-quality conditions. Streambed-sediment samples were analyzed for selected constituents, including trace elements and organic contaminants such as pesticides, polychlorinated biphenyls (PCBs), brominated flame retardants, and polycyclic aromatic hydrocarbons (PAHs). Potential risks of contaminants in sediment were evaluated by comparing concentrations of contaminants in sediment to two effects-based sediment-quality guidelines: (1) a lower level, called the threshold effect concentration, below which, harmful effects to benthic biota are not expected, and (2) a higher level, the probable effect concentration (PEC), above which harmful effects are expected to occur frequently. Samples for water-toxicity testing were collected from each stream to provide information about fish toxicity in the study area. The trace metal lead was detected at potentially toxic concentrations greater than the PEC in both the base-flow and poststorm samples collected at two sites sampled on San Pedro Creek. The PECs for the pesticides dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene, dichlorodiphenyltrichloroethane, and chlordane were exceeded in some of the samples at the same two sites on San Pedro Creek. Brominated flame retardants and polybrominated diphenyl ether (PBDE) 85, 153, and 154 were found in all streambed-sediment samples. Federal Environmental Quality Guidelines established by Environment Canada for PBDE 99 and PBDE 100 were exceeded in all samples in which PBDE 99 was detected and in a majority of the samples in which PBDE 100 was detected; the greatest concentrations occurred in samples collected at the same two sites on San Pedro Creek where the samples containing elevated lead and pesticide concentrations were collected. All concentrations of total PCBs (computed as the sum of the 18 reported PCB congeners) in the individual streambed-sediment samples were less than the threshold effect concentration, but the concentrations were elevated in the two sites on San Pedro Creek compared to concentrations at other sites. At one site on Apache Creek, 6 of the individual PAHs measured in the sample collected during base-flow conditions exceeded the PECs and 8 of the 9 PECs were exceeded in the sample collected during poststorm conditions. The total PAH concentration in the sample collected at the site during poststorm conditions was 3.3 times greater than the PEC developed for total PAHs. Average PAH profiles computed for base-flow samples and poststorm samples most closely resemble the parking lot coal-tar sealcoat dust PAH source profile, defined as the average PAH concentrations in dust swept from parking lots in six cities in the United States that were sealed with a black, viscous liquid containing coal-tar pitch. Six of ten water samples collected during base-flow conditions caused reductions in Pimephales promelas (fathead minnow) survival and were considered to be toxic.

Altitude training causes haematological fluctuations with relevance for the Athlete Biological Passport.

PubMed

Bonne, Thomas Christian; Lundby, Carsten; Lundby, Anne Kristine; Sander, Mikael; Bejder, Jacob; Nordsborg, Nikolai Baastrup

2015-08-01

The impact of altitude training on haematological parameters and the Athlete Biological Passport (ABP) was evaluated in international-level elite athletes. One group of swimmers lived high and trained high (LHTH, n = 10) for three to four weeks at 2130 m or higher whereas a control group (n = 10) completed a three-week training camp at sea-level. Haematological parameters were determined weekly three times before and four times after the training camps. ABP thresholds for haemoglobin concentration ([Hb]), reticulocyte percentage (RET%), OFF score and the abnormal blood profile score (ABPS) were calculated using the Bayesian model. After altitude training, six swimmers exceeded the 99% ABP thresholds: two swimmers exceeded the OFF score thresholds at day +7; one swimmer exceeded the OFF score threshold at day +28; one swimmer exceeded the threshold for RET% at day +14; and one swimmer surpassed the ABPS threshold at day +14. In the control group, no values exceeded the individual ABP reference range. In conclusion, LHTH induces haematological changes in Olympic-level elite athletes which can exceed the individually generated references in the ABP. Training at altitude should be considered a confounding factor for ABP interpretation for up to four weeks after altitude exposure but does not consistently cause abnormal values in the ABP. Copyright © 2014 John Wiley & Sons, Ltd.

16 CFR 801.20 - Acquisitions subsequent to exceeding threshold.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Acquisitions subsequent to exceeding threshold. 801.20 Section 801.20 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 COVERAGE RULES § 801.20 Acquisitions subsequent to exceeding...

16 CFR 801.20 - Acquisitions subsequent to exceeding threshold.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Acquisitions subsequent to exceeding threshold. 801.20 Section 801.20 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 COVERAGE RULES § 801.20 Acquisitions subsequent to exceeding...

Geographic distribution of selected elements in the livers of polar bears from Greenland, Canada and the United States.

PubMed

Rush, Scott A; Borgå, Katrine; Dietz, Rune; Born, Erik W; Sonne, Christian; Evans, Thomas; Muir, Derek C G; Letcher, Robert J; Norstrom, Ross J; Fisk, Aaron T

2008-06-01

To assess geographic distributions of elements in the Arctic we compared essential and non-essential elements in the livers of polar bears (Ursus maritimus) collected from five regions within Canada in 2002, in Alaska between 1994 and 1999 and from the northwest and east coasts of Greenland between 1988 and 2000. As, Hg, Pb and Se varied with age, and Co and Zn with gender, which limited spatial comparisons across all populations to Cd, which was highest in Greenland bears. Collectively, geographic relationships appeared similar to past studies with little change in concentration over time in Canada and Greenland for most elements; Hg and Se were higher in some Canadian populations in 2002 as compared to 1982 and 1984. Concentrations of most elements in the polar bears did not exceed toxicity thresholds, although Cd and Hg exceeded levels correlated with the formation of hepatic lesions in laboratory animals.

Hazardous waste status of discarded electronic cigarettes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krause, Max J.; Townsend, Timothy G., E-mail: ttown@ufl.edu

Highlights: • Electronic cigarettes were tested using TCLP and WET. • Several electronic cigarette products leached lead at hazardous waste levels. • Lead was the only element that exceeded hazardous waste concentration thresholds. • Nicotine solution may cause hazardous waste classification when discarded unused. - Abstract: The potential for disposable electronic cigarettes (e-cigarettes) to be classified as hazardous waste was investigated. The Toxicity Characteristic Leaching Procedure (TCLP) was performed on 23 disposable e-cigarettes in a preliminary survey of metal leaching. Based on these results, four e-cigarette products were selected for replicate analysis by TCLP and the California Waste Extraction Testmore » (WET). Lead was measured in leachate as high as 50 mg/L by WET and 40 mg/L by TCLP. Regulatory thresholds were exceeded by two of 15 products tested in total. Therefore, some e-cigarettes would be toxicity characteristic (TC) hazardous waste but a majority would not. When disposed in the unused form, e-cigarettes containing nicotine juice would be commercial chemical products (CCP) and would, in the United States (US), be considered a listed hazardous waste (P075). While household waste is exempt from hazardous waste regulation, there are many instances in which such waste would be subject to regulation. Manufactures and retailers with unused or expired e-cigarettes or nicotine juice solution would be required to manage these as hazardous waste upon disposal. Current regulations and policies regarding the availability of nicotine-containing e-cigarettes worldwide were reviewed. Despite their small size, disposable e-cigarettes are consumed and discarded much more quickly than typical electronics, which may become a growing concern for waste managers.« less

Spatial patterns of methylmercury risks to common loons and piscivorous fish in Canada.

PubMed

Depew, David C; Burgess, Neil M; Campbell, Linda M

2013-11-19

Deposition of inorganic mercury (Hg) from the atmosphere remains the principle source of Hg contamination for most aquatic ecosystems. Inorganic Hg is readily converted to toxic methylmercury (MeHg) that bioaccumulates in aquatic food webs and may pose a risk to piscivorous fish and wildlife. We conducted a screening-level risk assessment to evaluate the extent of risk to top aquatic piscivores: the common loon (Gavia immer), walleye (Sander vitreus), and northern pike (Esox lucius). Risk quotients (RQs) were calculated on the basis of a dietary Hg exposure indicator (HgPREY) modeled from over 230,000 observations of fish Hg concentrations at over 1900 locations across Canada and dietary Hg exposure screening benchmarks derived specifically for this assessment. HgPREY exceeded benchmark thresholds related to impaired productivity and behavior in adult loons at 10% and 36% of sites, respectively, and exceeded benchmark thresholds for impaired reproduction and health in fishes at 82% and 73% of sites, respectively. The ecozones of southeastern Canada characterized by extensive forest cover, elevated Hg deposition, and poorly buffered soils had the greatest proportion of RQs > 1.0. Results of this assessment suggest that common loons and piscivorous fishes would likely benefit from reductions in Hg deposition, especially in southeastern Canada.

Microcystin Prevalence throughout Lentic Waterbodies in Coastal Southern California

PubMed Central

Nagoda, Carey; Kudela, Raphael M.; Tatters, Avery; Caron, David A.; Busse, Lilian; Brown, Jeff; Sutula, Martha

2017-01-01

Toxin producing cyanobacterial blooms have increased globally in recent decades in both frequency and intensity. Despite the recognition of this growing risk, the extent and magnitude of cyanobacterial blooms and cyanotoxin prevalence is poorly characterized in the heavily populated region of southern California. Recent assessments of lentic waterbodies (depressional wetlands, lakes, reservoirs and coastal lagoons) determined the prevalence of microcystins and, in some cases, additional cyanotoxins. Microcystins were present in all waterbody types surveyed although toxin concentrations were generally low across most habitats, as only a small number of sites exceeded California’s recreational health thresholds for acute toxicity. Results from passive samplers (Solid Phase Adsorption Toxin Tracking (SPATT)) indicated microcystins were prevalent throughout lentic waterbodies and that traditional discrete samples underestimated the presence of microcystins. Multiple cyanotoxins were detected simultaneously in some systems, indicating multiple stressors, the risk of which is uncertain since health thresholds are based on exposures to single toxins. Anatoxin-a was detected for the first time from lakes in southern California. The persistence of detectable microcystins across years and seasons indicates a low-level, chronic risk through both direct and indirect exposure. The influence of toxic cyanobacterial blooms is a more complex stressor than presently recognized and should be included in water quality monitoring programs. PMID:28737685

Second Opinions Improve ADHD Prescribing in a Medicaid-Insured Community Population

ERIC Educational Resources Information Center

Thompson, Jeffrey N.; Varley, Christopher K.; McClellan, Jon; Hilt, Robert; Lee, Terry; Kwan, Alan C.; Lee, Taik; Trupin, Eric

2009-01-01

Washington State Medicaid mandates a second opinion when threshold safety parameters for attention deficit hyperactivity disorder (ADHD) medications are exceeded. This is found to save $1.2 million and saves 538 fewer patients from exceeding safety thresholds.

Environmental Assessment: West Coast Basing of C-17 Aircraft

DTIC Science & Technology

2003-06-01

will not be regionally significant by United States Environmental Protection Agency standards, will not exceed de minimis thresholds, and that a...emissions for criteria pollutants will not be regionally significant by United States Environmental Protection Agency standards, will not exceed de minimis...would not exceed de minimis thresholds, and that a Conformity Determination would not be required. MTRs. Emissions from C-17 operations on the

Toxic and inhibitory effects of trichloroethylene aerobic co-metabolism on phenol-grown aerobic granules.

PubMed

Zhang, Yi; Tay, JooHwa

2015-04-09

Aerobic granule, a form of microbial aggregate, exhibits good potential in degrading toxic and recalcitrant substances. In this study, the inhibitory and toxic effects of trichloroethylene (TCE), a model compound for aerobic co-metabolism, on phenol-grown aerobic granules were systematically studied, using respiratory activities after exposure to TCE as indicators. High TCE concentration did not exert positive or negative effects on the subsequent endogenous respiration rate or phenol dependent specific oxygen utilization rate (SOUR), indicating the absence of solvent stress and induction effect on phenol-hydroxylase. Phenol-grown aerobic granules exhibited a unique response to TCE transformation product toxicity, that small amount of TCE transformation enhanced the subsequent phenol SOUR. Granules that had transformed between 1.3 and 3.7 mg TCE gSS(-1) showed at most 53% increase in the subsequent phenol SOUR, and only when the transformation exceeded 6.6 mg TCE gSS(-1) did the SOUR dropped below that of the control. This enhancing effect was found to sustain throughout several phenol dosages, and TCE transformation below the toxicity threshold also lessened the granules' sensitivity to higher phenol concentration. The unique toxic effect was possibly caused by the granule's compact structure as a protection barrier against the diffusive transformation product(s) of TCE co-metabolism. Copyright © 2015 Elsevier B.V. All rights reserved.

Environmental contaminants and biomarker responses in fish from the Columbia River and its tributaries: spatial and temporal trends.

PubMed

Hinck, Jo Ellen; Schmitt, Christopher J; Blazer, Vicki S; Denslow, Nancy D; Bartish, Timothy M; Anderson, Patrick J; Coyle, James J; Dethloff, Gail M; Tillitt, Donald E

2006-08-01

Fish were collected from 16 sites on rivers in the Columbia River Basin (CRB) from September 1997 to April 1998 to document temporal and spatial trends in the concentrations of accumulative contaminants and to assess contaminant effects on the fish. Sites were located on the mainstem of the Columbia River and on the Snake, Willamette, Yakima, Salmon, and Flathead Rivers. Common carp (Cyprinus carpio), black bass (Micropterus sp.), and largescale sucker (Catostomus macrocheilus) were the targeted species. Fish were field-examined for external and internal lesions, selected organs were weighed to compute somatic indices, and tissue and fluid samples were preserved for fish health and reproductive biomarker analyses. Composite samples of whole fish, grouped by species and gender, from each site were analyzed for organochlorine and elemental contaminants using instrumental methods and for 2,3,7,8-tetrachloro dibenzo-p-dioxin-like activity (TCDD-EQ) using the H4IIE rat hepatoma cell bioassay. Overall, pesticide concentrations were greatest in fish from lower CRB sites and elemental concentrations were greatest in fish from upper CRB sites. These patterns reflected land uses. Lead (Pb) concentrations in fish from the Columbia River at Northport and Grand Coulee, Washington (WA) exceeded fish and wildlife toxicity thresholds (>0.4 microg/g). Selenium (Se) concentrations in fish from the Salmon River at Riggins, Idaho (ID), the Columbia River at Vernita Bridge, WA, and the Yakima River at Granger, WA exceeded toxicity thresholds for piscivorous wildlife (>0.6 microg/g). Mercury (Hg) concentrations in fish were elevated throughout the basin but were greatest (>0.4 microg/g) in predatory fish from the Salmon River at Riggins, ID, the Yakima River at Granger, WA, and the Columbia River at Warrendale, Oregon (OR). Residues of p,p'-DDE were greatest (>0.8 microg/g) in fish from agricultural areas of the Snake, Yakima, and Columbia River basins but were not detected in upper CRB fish. Other organochlorine pesticides did not exceed toxicity thresholds in fish or were detected infrequently. Total polychlorinated biphenyls (PCBs; >0.11 microg/g) and TCDD-EQs (>5 pg/g) exceeded wildlife guidelines in fish from the middle and lower CRB, and ethoxyresorufin O-deethylase (EROD) activity was also elevated at many of the same sites. Temporal trend analysis indicated decreasing or stable concentrations of Pb, Se, Hg, p,p'-DDE, and PCBs at most sites where historical data were available. Altered biomarkers were noted in fish throughout the CRB. Fish from some stations had responded to chronic contaminant exposure as indicated by fish health and reproductive biomarker results. Although most fish from some sites had grossly visible external or internal lesions, histopathological analysis determined these to be inflammatory responses associated with helminth or myxosporidian parasites. Many largescale sucker from the Columbia River at Northport and Grand Coulee, WA had external lesions and enlarged spleens, which were likely associated with infections. Intersex male smallmouth bass (Micropterus dolomieu) were found in the Snake River at Lewiston, ID and the Columbia River at Warrendale, OR. Male bass, carp, and largescale sucker containing low concentrations of vitellogenin were common in the CRB, and comparatively high concentrations (>0.3 mg/mL) were measured in male fish from the Flathead River at Creston, Montana, the Snake River at Ice Harbor Dam, WA, and the Columbia River at Vernita Bridge, WA and Warrendale, OR. Results from our study and other investigations indicate that continued monitoring in the CRB is warranted to identify consistently degraded sites and those with emerging problems.

Distribution and pollution, toxicity and risk assessment of heavy metals in sediments from urban and rural rivers of the Pearl River delta in southern China.

PubMed

Xiao, Rong; Bai, Junhong; Huang, Laibin; Zhang, Honggang; Cui, Baoshan; Liu, Xinhui

2013-12-01

Sediments were collected from the upper, middle and lower reaches of both urban and rural rivers in a typical urbanization zone of the Pearl River delta. Six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) were analyzed in all sediment samples, and their spatial distribution, pollution levels, toxicity and ecological risk levels were evaluated to compare the characteristics of heavy metal pollution between the two rivers. Our results indicated that the total contents of the six metals in all samples exceeded the soil background value in Guangdong province. Based on the soil quality thresholds of the China SEPA, Cd levels at all sites exceeded class III criteria, and other metals exhibited pollution levels exceeding class II or III criteria at both river sites. According to the sediment quality guidelines of the US EPA, all samples were moderately to heavily polluted by Cr, Cu, Ni, Pb and Zn. Compared to rural river sites, urban river sites exhibited heavier pollution. Almost all sediment samples from both rivers exhibited moderate to serious toxicity to the environment, with higher contributions from Cr and Ni. A "hot area" of heavy metal pollution being observed in the upper and middle reaches of the urban river area, whereas a "hot spot" was identified at a specific site in the middle reach of the rural river. Contrary metal distribution patterns were also observed along typical sediment profiles from urban and rural rivers. However, the potential ecological risk indices of rural river sediments in this study were equal to those of urban river sediments, implying that the ecological health issues of the rivers in the undeveloped rural area should also be addressed. Sediment organic matter and grain size might be important factors influencing the distribution profiles of these heavy metals.

How parents perceive screen viewing in their 5-6 year old child within the context of their own screen viewing time: a mixed-methods study.

PubMed

Thompson, Janice L; Sebire, Simon J; Kesten, Joanna M; Zahra, Jesmond; Edwards, Mark; Solomon-Moore, Emma; Jago, Russell

2017-06-01

Few studies have examined parental perceptions of their child's screen-viewing (SV) within the context of parental SV time. This study qualitatively examined parents' perceptions of their 5-6-year-old child's SV within the context of their own quantitatively measured SV. A mixed-methods design employed semi-structured telephone interviews, demographic and SV questionnaires, objectively-measured physical activity and sedentary time. Deductive content analysis was used to explore parents' perceptions of, and concerns about, their child's SV, and management of their child's SV. Comparisons were made between parent-child dyads reporting low (<2-h per day) versus high SV time. Fifty-three parents were interviewed (94.3% mothers), with 52 interviews analysed. Fifteen parent-child dyads (28.8%) exceeded the 2-h SV threshold on both weekdays and weekend days; 5 parent-child dyads (9.6%) did not exceed this threshold. The remaining 32 dyads reported a combination of parent or child exceeding/not exceeding the SV threshold on either weekdays or weekend days. Three main themes distinguished the 15 parent-child dyads exceeding the SV threshold from the 5 dyads that did not: 1) parents' personal SV-related views and behaviours; 2) the family SV environment; and 3) setting SV rules and limits. Parents in the dyads not exceeding the SV threshold prioritized and engaged with their children in non-SV behaviours for relaxation, set limits around their own and their child's SV-related behaviours, and described an environment supportive of physical activity. Parents in the dyads exceeding the SV threshold were more likely to prioritise SV as a shared family activity, and described a less structured SV environment with minimal rule setting, influenced their child's need for relaxation time. The majority of parents in this study who exceeded the SV threshold expressed minimal concern and a relaxed approach to managing SV for themselves and their child(ren), suggesting a need to raise awareness amongst these parents about the time they spend engaging in SV. Parents may understand their SV-related parenting practices more clearly if they are encouraged to examine their own SV behaviours. Designing interventions aimed to create environments that are less supportive of SV, with more structured approaches to SV parenting strategies are warranted.

48 CFR 8.405-6 - Limiting sources.

Code of Federal Regulations, 2013 CFR

2013-10-01

... or BPA with an estimated value exceeding the micro-purchase threshold not placed or established in... Schedule ordering procedures. The original order or BPA must not have been previously issued under sole... order or BPA exceeding the simplified acquisition threshold. (2) Posting. (i) Within 14 days after...

48 CFR 8.405-6 - Limiting sources.

Code of Federal Regulations, 2011 CFR

2011-10-01

... or BPA with an estimated value exceeding the micro-purchase threshold not placed or established in... Schedule ordering procedures. The original order or BPA must not have been previously issued under sole... order or BPA exceeding the simplified acquisition threshold. (2) Posting. (i) Within 14 days after...

48 CFR 8.405-6 - Limiting sources.

Code of Federal Regulations, 2012 CFR

2012-10-01

... or BPA with an estimated value exceeding the micro-purchase threshold not placed or established in... Schedule ordering procedures. The original order or BPA must not have been previously issued under sole... order or BPA exceeding the simplified acquisition threshold. (2) Posting. (i) Within 14 days after...

48 CFR 8.405-6 - Limiting sources.

Code of Federal Regulations, 2014 CFR

2014-10-01

... or BPA with an estimated value exceeding the micro-purchase threshold not placed or established in... Schedule ordering procedures. The original order or BPA must not have been previously issued under sole... order or BPA exceeding the simplified acquisition threshold. (2) Posting. (i) Within 14 days after...

Evaluation of Potential Exposure to Metals in Laundered Shop Towels

PubMed Central

Greenberg, Grace; Beck, Barbara D.

2013-01-01

We reported in 2003 that exposure to metals on laundered shop towels (LSTs) could exceed toxicity criteria. New data from LSTs used by workers in North America document the continued presence of metals in freshly laundered towels. We assessed potential exposure to metals based on concentrations of metals on the LSTs, estimates of LST usage by employees, and the transfer of metals from LST-to-hand, hand-to-mouth, and LST-to-lip, under average- or high-exposure scenarios. Exposure estimates were compared to toxicity criteria. Under an average-exposure scenario (excluding metals' data outliers), exceedances of the California Environmental Protection Agency, U.S. Environmental Protection Agency, and the Agency for Toxic Substances and Disease Registry toxicity criteria may occur for aluminum, cadmium, cobalt, copper, iron, and lead. Calculated intakes for these metals were up to more than 400-fold higher (lead) than their respective toxicity criterion. For the high-exposure scenario, additional exceedances may occur, and high-exposure intakes were up to 1,170-fold higher (lead) than their respective toxicity criterion. A sensitivity analysis indicated that alternate plausible assumptions could increase or decrease the magnitude of exceedances, but were unlikely to eliminate certain exceedances, particularly for lead. PMID:24453472

Estimating the Pollution Risk of Cadmium in Soil Using a Composite Soil Environmental Quality Standard

PubMed Central

Huang, Biao; Zhao, Yongcun

2014-01-01

Estimating standard-exceeding probabilities of toxic metals in soil is crucial for environmental evaluation. Because soil pH and land use types have strong effects on the bioavailability of trace metals in soil, they were taken into account by some environmental protection agencies in making composite soil environmental quality standards (SEQSs) that contain multiple metal thresholds under different pH and land use conditions. This study proposed a method for estimating the standard-exceeding probability map of soil cadmium using a composite SEQS. The spatial variability and uncertainty of soil pH and site-specific land use type were incorporated through simulated realizations by sequential Gaussian simulation. A case study was conducted using a sample data set from a 150 km2 area in Wuhan City and the composite SEQS for cadmium, recently set by the State Environmental Protection Administration of China. The method may be useful for evaluating the pollution risks of trace metals in soil with composite SEQSs. PMID:24672364

Metal-binding hydrogel particles alleviate soil toxicity and facilitate healthy plant establishment of the native metallophyte grass Astrebla lappacea in mine waste rock and tailings.

PubMed

Bigot, M; Guterres, J; Rossato, L; Pudmenzky, A; Doley, D; Whittaker, M; Pillai-McGarry, U; Schmidt, S

2013-03-15

Soil contaminants are potentially a major threat to human and ecosystem health and sustainable production of food and energy where mineral processing wastes are discharged into the environment. In extreme conditions, metal concentrations in wastes often exceed even the metal tolerance thresholds of metallophytes (metal-tolerant plants) and sites remain barren with high risks of contaminant leaching and dispersion into the environment via erosion. A novel soil amendment based on micron-size thiol functional cross-linked acrylamide polymer hydrogel particles (X3) binds toxic soluble metals irreversibly and significantly reduces their concentrations in the soil solution to below the phytotoxicity thresholds. X3 mixed into the top 50mm of phytotoxic mine waste materials in pots in glasshouse conditions reduced total soluble concentrations of toxic contaminants by 90.3-98.7% in waste rock, and 88.6-96.4% in tailings immediately after application. After 61 days, quality of unamended bottom layer of X3-treated pots was also significantly improved in both wastes. Combination of X3 and metallophytes was more efficient at improving soil solution quality than X3 alone. Addition of X3 to substrates increased substrate water retention and water availability to plants by up to 108% and 98% for waste rock and tailings respectively. Soil quality improvement by X3 allowed successful early establishment of the native metallophyte grass Astrebla lappacea on both wastes where plants failed to establish otherwise. Copyright © 2013 Elsevier B.V. All rights reserved.

Deriving freshwater safety thresholds for hexabromocyclododecane and comparison of toxicity of brominated flame retardants.

PubMed

Dong, Liang; Zheng, Lei; Yang, Suwen; Yan, Zhenguang; Jin, Weidong; Yan, Yuhong

2017-05-01

Hexabromocyclododecane (HBCD) is a brominated flame retardant used throughout the world. It has been detected in various environmental media and has been shown toxic to aquatic life. The toxic effects of HBCD to aquatic organisms in Chinese freshwater ecosystems are discussed here. Experiments were conducted with nine types of acute toxicity testing and three types of chronic toxicity testing. After comparing a range of species sensitivity distribution models, the optimal model of Bull III was used to derive the safety thresholds for HBCD. The acute safety threshold and the chronic safety threshold of HBCD for Chinese freshwater organisms were found to be 2.32mg/L and 0.128mg/L, respectively. Both values were verified by the methods of the Netherlands and the United States. HBCD was found to be less toxic compared to other widely used brominated flame retardants. The present results provide valuable information for revision of the water quality standard of HBCD in China. Copyright © 2017 Elsevier Inc. All rights reserved.

OPTIMIZING THE PRECISION OF TOXICITY THRESHOLD ESTIMATION USING A TWO-STAGE EXPERIMENTAL DESIGN

EPA Science Inventory

An important consideration for risk assessment is the existence of a threshold, i.e., the highest toxicant dose where the response is not distinguishable from background. We have developed methodology for finding an experimental design that optimizes the precision of threshold mo...

Estimating soil moisture exceedance probability from antecedent rainfall

NASA Astrophysics Data System (ADS)

Cronkite-Ratcliff, C.; Kalansky, J.; Stock, J. D.; Collins, B. D.

2016-12-01

The first storms of the rainy season in coastal California, USA, add moisture to soils but rarely trigger landslides. Previous workers proposed that antecedent rainfall, the cumulative seasonal rain from October 1 onwards, had to exceed specific amounts in order to trigger landsliding. Recent monitoring of soil moisture upslope of historic landslides in the San Francisco Bay Area shows that storms can cause positive pressure heads once soil moisture values exceed a threshold of volumetric water content (VWC). We propose that antecedent rainfall could be used to estimate the probability that VWC exceeds this threshold. A major challenge to estimating the probability of exceedance is that rain gauge records are frequently incomplete. We developed a stochastic model to impute (infill) missing hourly precipitation data. This model uses nearest neighbor-based conditional resampling of the gauge record using data from nearby rain gauges. Using co-located VWC measurements, imputed data can be used to estimate the probability that VWC exceeds a specific threshold for a given antecedent rainfall. The stochastic imputation model can also provide an estimate of uncertainty in the exceedance probability curve. Here we demonstrate the method using soil moisture and precipitation data from several sites located throughout Northern California. Results show a significant variability between sites in the sensitivity of VWC exceedance probability to antecedent rainfall.

The Impact of a Nickel-Copper Smelter on Concentrations of Toxic Elements in Local Wild Food from the Norwegian, Finnish, and Russian Border Regions

PubMed Central

Hansen, Martine D.; Nøst, Therese H.; Heimstad, Eldbjørg S.; Evenset, Anita; Dudarev, Alexey A.; Rautio, Arja; Myllynen, Päivi; Dushkina, Eugenia V.; Jagodic, Marta; Christensen, Guttorm N.; Anda, Erik E.; Brustad, Magritt; Sandanger, Torkjel M.

2017-01-01

Toxic elements emitted from the Pechenganickel complex on the Kola Peninsula have caused concern about potential effects on local wild food in the border regions between Norway, Finland and Russia. The aim of this study was to assess Ni, Cu, Co, As, Pb, Cd, and Hg concentrations in local wild foods from these border regions. During 2013–2014, we collected samples of different berry, mushroom, fish, and game species from sites at varying distances from the Ni-Cu smelter in all three border regions. Our results indicate that the Ni-Cu smelter is the main source of Ni, Co, and As in local wild foods, whereas the sources of Pb and Cd are more complex. We observed no consistent trends for Cu, one of the main toxic elements emitted by the Ni-Cu smelter; nor did we find any trend for Hg in wild food. Concentrations of all investigated toxic elements were highest in mushrooms, except for Hg, which was highest in fish. EU maximum levels of Pb, Cd, and Hg were exceeded in some samples, but most had levels considered safe for human consumption. No international thresholds exist for the other elements under study. PMID:28657608

The Impact of a Nickel-Copper Smelter on Concentrations of Toxic Elements in Local Wild Food from the Norwegian, Finnish, and Russian Border Regions.

PubMed

Hansen, Martine D; Nøst, Therese H; Heimstad, Eldbjørg S; Evenset, Anita; Dudarev, Alexey A; Rautio, Arja; Myllynen, Päivi; Dushkina, Eugenia V; Jagodic, Marta; Christensen, Guttorm N; Anda, Erik E; Brustad, Magritt; Sandanger, Torkjel M

2017-06-28

Toxic elements emitted from the Pechenganickel complex on the Kola Peninsula have caused concern about potential effects on local wild food in the border regions between Norway, Finland and Russia. The aim of this study was to assess Ni, Cu, Co, As, Pb, Cd, and Hg concentrations in local wild foods from these border regions. During 2013-2014, we collected samples of different berry, mushroom, fish, and game species from sites at varying distances from the Ni-Cu smelter in all three border regions. Our results indicate that the Ni-Cu smelter is the main source of Ni, Co, and As in local wild foods, whereas the sources of Pb and Cd are more complex. We observed no consistent trends for Cu, one of the main toxic elements emitted by the Ni-Cu smelter; nor did we find any trend for Hg in wild food. Concentrations of all investigated toxic elements were highest in mushrooms, except for Hg, which was highest in fish. EU maximum levels of Pb, Cd, and Hg were exceeded in some samples, but most had levels considered safe for human consumption. No international thresholds exist for the other elements under study.

Simulation of metals transport and toxicity at a mine-impacted watershed: California Gulch, Colorado.

PubMed

Velleux, Mark L; Julien, Pierre Y; Rojas-Sanchez, Rosalia; Clements, William H; England, John F

2006-11-15

The transport and toxicity of metals at the California Gulch, Colorado mine-impacted watershed were simulated with a spatially distributed watershed model. Using a database of observations for the period 1984-2004, hydrology, sediment transport, and metals transport were simulated for a June 2003 calibration event and a September 2003 validation event. Simulated flow volumes were within approximately 10% of observed conditions. Observed ranges of total suspended solids, cadmium, copper, and zinc concentrations were also successfully simulated. The model was then used to simulate the potential impacts of a 1-in-100-year rainfall event. Driven by large flows and corresponding soil and sediment erosion for the 1-in-100-year event, estimated solids and metals export from the watershed is 10,000 metric tons for solids, 215 kg for Cu, 520 kg for Cu, and 15,300 kg for Zn. As expressed by the cumulative criterion unit (CCU) index, metals concentrations far exceed toxic effects thresholds, suggesting a high probability of toxic effects downstream of the gulch. More detailed Zn source analyses suggest that much of the Zn exported from the gulch originates from slag piles adjacent to the lower gulch floodplain and an old mining site located near the head of the lower gulch.

Lead toxicity thresholds in 17 Chinese soils based on substrate-induced nitrification assay.

PubMed

Li, Ji; Huang, Yizong; Hu, Ying; Jin, Shulan; Bao, Qiongli; Wang, Fei; Xiang, Meng; Xie, Huiting

2016-06-01

The influence of soil properties on toxicity threshold values for Pb toward soil microbial processes is poorly recognized. The impact of leaching on the Pb threshold has not been assessed systematically. Lead toxicity was screened in 17 Chinese soils using a substrate-induced nitrification (SIN) assay under both leached and unleached conditions. The effective concentration of added Pb causing 50% inhibition (EC50) ranged from 185 to >2515mg/kg soil for leached soil and 130 to >2490mg/kg soil for unleached soil. These results represented >13- and >19-fold variations among leached and unleached soils, respectively. Leaching significantly reduced Pb toxicity for 70% of both alkaline and acidic soils tested, with an average leaching factor of 3.0. Soil pH and CEC were the two most useful predictors of Pb toxicity in soils, explaining over 90% of variance in the unleached EC50 value. The relationships established in the present study predicted Pb toxicity within a factor of two of measured values. These relationships between Pb toxicity and soil properties could be used to establish site-specific guidance on Pb toxicity thresholds. Copyright © 2016. Published by Elsevier B.V.

2008 Toxic Chemical Release Inventory 2008 Toxic Chemical Release Inventory Community Right-to-Know Act of 1986, Title III, Section 313

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ecology and Air Quality Group

2009-10-01

For reporting year 2008, Los Alamos National Laboratory (LANL) submitted a Form R report for lead as required under the Emergency Planning and Community Right-to- Know Act (EPCRA) Section 313. No other EPCRA Section 313 chemicals were used in 2008 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2008, as well as to provide background information about data included on the Form R reports. Section 313 of EPCRA specifically requires facilities to submit a Toxic Chemical Release Inventory Reportmore » (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. In 1999, EPA promulgated a final rule on persistent bioaccumulative toxics (PBTs). This rule added several chemicals to the EPCRA Section 313 list of toxic chemicals and established lower reporting thresholds for these and other PBT chemicals that were already reportable. These lower thresholds became applicable in reporting year 2000. In 2001, EPA expanded the PBT rule to include a lower reporting threshold for lead and lead compounds. Facilities that manufacture, process, or otherwise use more than 100 lb of lead or lead compounds must submit a Form R.« less

40 CFR 68.115 - Threshold determination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Threshold determination. 68.115... § 68.115 Threshold determination. (a) A threshold quantity of a regulated substance listed in § 68.130... process exceeds the threshold. (b) For the purposes of determining whether more than a threshold quantity...

40 CFR 372.25 - Thresholds for reporting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW... threshold amounts for purposes of reporting under § 372.30 for toxic chemicals are as follows: (a) With respect to a toxic chemical manufactured (including imported) or processed at a facility during the...

40 CFR 372.25 - Thresholds for reporting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW... threshold amounts for purposes of reporting under § 372.30 for toxic chemicals are as follows: (a) With respect to a toxic chemical manufactured (including imported) or processed at a facility during the...

Bioremediation of copper-contaminated soils by bacteria.

PubMed

Cornu, Jean-Yves; Huguenot, David; Jézéquel, Karine; Lollier, Marc; Lebeau, Thierry

2017-02-01

Although copper (Cu) is an essential micronutrient for all living organisms, it can be toxic at low concentrations. Its beneficial effects are therefore only observed for a narrow range of concentrations. Anthropogenic activities such as fungicide spraying and mining have resulted in the Cu contamination of environmental compartments (soil, water and sediment) at levels sometimes exceeding the toxicity threshold. This review focuses on the bioremediation of copper-contaminated soils. The mechanisms by which microorganisms, and in particular bacteria, can mobilize or immobilize Cu in soils are described and the corresponding bioremediation strategies-of varying levels of maturity-are addressed: (i) bioleaching as a process for the ex situ recovery of Cu from Cu-bearing solids, (ii) bioimmobilization to limit the in situ leaching of Cu into groundwater and (iii) bioaugmentation-assisted phytoextraction as an innovative process for in situ enhancement of Cu removal from soil. For each application, the specific conditions required to achieve the desired effect and the practical methods for control of the microbial processes were specified.

A recent history of metal accumulation in the sediments of Rijeka harbor, Adriatic Sea, Croatia.

PubMed

Cukrov, Neven; Frančišković-Bilinski, Stanislav; Hlača, Bojan; Barišić, Delko

2011-01-01

We studied metal pollution in the sediments of Rijeka harbor, including anthropogenic influence during recent decades and at the present time. Sediment profiles were collected at ten sampling points. The concentrations of 63 elements in bulk sediment were obtained using ICP-MS, and the concentrations of selected elements were evaluated by statistical factor analyses. We also calculated metal-enrichment factors and geoaccumulation indices and constructed spatial-distribution maps. Mercury (Hg) was the heaviest pollutant, with concentrations exceeding 4 mg/kg. Silver (Ag) was the second most important pollutant, with constantly increasing values. The average concentrations of the most toxic elements were comparable to those found in sediments of other ports throughout the world, and their toxicity ranged from threshold values [chromium (Cr), arsenic (As)] and midrange-effect values [cadmium (Cd), lead (Pb), copper (Cu), zinc (Zn), nickel (Ni)] to extreme-effect values (Hg). Metal pollution has decreased during recent decades, except for Ag and barium (Ba). Copyright © 2010 Elsevier Ltd. All rights reserved.

The toxic exposure of flamingos to per- and Polyfluoroalkyl substances (PFAS) from firefighting foam applications in Bonaire.

PubMed

de Vries, Pepijn; Slijkerman, Diana M E; Kwadijk, Christiaan J A F; Kotterman, Michiel J J; Posthuma, Leo; de Zwart, Dick; Murk, Albertinka J; Foekema, Edwin M

2017-11-15

In 2010 an oil terminal next to nature reservation Saliña Goto (Bonaire) caught fire. Firefighting resulted in elevated per- and polyfluoroalkyl substances (PFAS) concentrations in the salt lake. Within months flamingo abundance in Goto dropped to near complete absence. After statistical analysis, rainfall was deemed an unlikely cause for this decline. Toxicological effects on abundance of prey are likely the main cause for the flamingo absence. This reduced PFAS exposure via food and thus risk towards flamingos during the first years after the fires. Although the sediment is still polluted with persistent PFAS, flamingos returned, and started to feed on organisms with PFAS levels that exceed safety thresholds, placing the birds and other wildlife at risk. Monitoring bird populations is advised to assess potential toxic effects on birds and their offspring. This case suggests that applying persistent chemicals to reduce incident impacts may be more harmful than the incident itself. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and evaluation of sediment quality guidelines for Florida coastal waters

USGS Publications Warehouse

MacDonald, Donald D.; Carr, R. Scott; Calder, Fred D.; Long, Edward R.; Ingersoll, Christopher G.

1996-01-01

The weight-of-evidence approach to the development of sediment quality guidelines (SQGs) was modified to support the derivation of biological effects-based SQGs for Florida coastal waters. Numerical SQGs were derived for 34 substances, including nine trace metals, 13 individual polycyclic aromatic hydrocarbons (PAHs), three groups of PAHs, total polychlorinated biphenyls (PCBs), seven pesticides and one phthalate ester. For each substance, a threshold effects level (TEL) and a probable effects level (PEL) was calculated. These two values defined three ranges of chemical concentrations, including those that were (1) rarely, (2) occasionally or (3) frequently associated with adverse effects. The SQGs were then evaluated to determine their degree of agreement with other guidelines (an indicator of comparability) and the percent incidence of adverse effects within each concentration range (an indicator of reliability). The guidelines also were used to classify (using a dichotomous system: toxic, with one or more exceedances of the PELs or non-toxic, with no exceedances of the TELs) sediment samples collected from various locations in Florida and the Gulf of Mexico. The accuracy of these predictions was then evaluated using the results of the biological tests that were performed on the same sediment samples. The resultant SQGs were demonstrated to provide practical, reliable and predictive tools for assessing sediment quality in Florida and elsewhere in the southeastern portion of the United States.

Neonicotinoid contamination of global surface waters and associated risk to aquatic invertebrates: a review.

PubMed

Morrissey, Christy A; Mineau, Pierre; Devries, James H; Sanchez-Bayo, Francisco; Liess, Matthias; Cavallaro, Michael C; Liber, Karsten

2015-01-01

Neonicotinoids, broad-spectrum systemic insecticides, are the fastest growing class of insecticides worldwide and are now registered for use on hundreds of field crops in over 120 different countries. The environmental profile of this class of pesticides indicate that they are persistent, have high leaching and runoff potential, and are highly toxic to a wide range of invertebrates. Therefore, neonicotinoids represent a significant risk to surface waters and the diverse aquatic and terrestrial fauna that these ecosystems support. This review synthesizes the current state of knowledge on the reported concentrations of neonicotinoids in surface waters from 29 studies in 9 countries world-wide in tandem with published data on their acute and chronic toxicity to 49 species of aquatic insects and crustaceans spanning 12 invertebrate orders. Strong evidence exists that water-borne neonicotinoid exposures are frequent, long-term and at levels (geometric means=0.13μg/L (averages) and 0.63μg/L (maxima)) which commonly exceed several existing water quality guidelines. Imidacloprid is by far the most widely studied neonicotinoid (66% of the 214 toxicity tests reviewed) with differences in sensitivity among aquatic invertebrate species ranging several orders of magnitude; other neonicotinoids display analogous modes of action and similar toxicities, although comparative data are limited. Of the species evaluated, insects belonging to the orders Ephemeroptera, Trichoptera and Diptera appear to be the most sensitive, while those of Crustacea (although not universally so) are less sensitive. In particular, the standard test species Daphnia magna appears to be very tolerant, with 24-96hour LC50 values exceeding 100,000μg/L (geometric mean>44,000μg/L), which is at least 2-3 orders of magnitude higher than the geometric mean of all other invertebrate species tested. Overall, neonicotinoids can exert adverse effects on survival, growth, emergence, mobility, and behavior of many sensitive aquatic invertebrate taxa at concentrations at or below 1μg/L under acute exposure and 0.1μg/L for chronic exposure. Using probabilistic approaches (species sensitivity distributions), we recommend here that ecological thresholds for neonicotinoid water concentrations need to be below 0.2μg/L (short-term acute) or 0.035μg/L (long-term chronic) to avoid lasting effects on aquatic invertebrate communities. The application of safety factors may still be warranted considering potential issues of slow recovery, additive or synergistic effects and multiple stressors that can occur in the field. Our analysis revealed that 81% (22/27) and 74% (14/19) of global surface water studies reporting maximum and average individual neonicotinoid concentrations respectively, exceeded these thresholds of 0.2 and 0.035μg/L. Therefore, it appears that environmentally relevant concentrations of neonicotinoids in surface waters worldwide are well within the range where both short- and long-term impacts on aquatic invertebrate species are possible over broad spatial scales. Copyright © 2014 Elsevier Ltd. All rights reserved.

Health related guide values for drinking-water since 1993 as guidance to assess presence of new analytes in drinking-water.

PubMed

Dieter, Hermann H

2014-03-01

Regulatory toxicologists, when going into assessment of a new analyte in drinking-water, very often miss the occasion to revert to scientifically consensual virtually safe lifetime exposure reference doses and corresponding health-related guide values (HRGV) for drinking-water, be those derived either to avoid concern over "threshold effects" or concern over exceedance of an unacceptable non-threshold cancer risk level. They then need a more restrictive precautionary yet science-compatible approach to directly avoid concern over the presence (measured concentration) of a new analyte in drinking-water. Therefore, the German Environment Agency (UBA, Umweltbundesamt) decided in 2003 to extrapolate international toxicological expertise collected since 1993 from assessing "old" analytes in drinking-water on new ones in form of five HRIV=health related indication values. They indicate the reasonable lowest maximal concentration from which on tiered or stepwise human toxicological evaluation of a new analyte might be necessary and meaningful. Their regulatory-toxicological function is that of placeholders as long as a possibly higher scientific HRGV or a surrogate value based on a threshold of toxicological concern (TTC) was not broadly agreed by science. The five-step HRIV scale between 0.01 and 3.0 μg/l combines international toxicological experience gained from "old" analytes since 1993 with the concepts of safety factors (SF(D)) to assess database deficiency and science-related extrapolation factors (EF) to extrapolate experimental data on humans. Each HRIV is valid and safe for a 2 l/day drinking-water exposure scenario either counting for 10% relative source contribution (compounds with threshold effects) or for a lifetime non-threshold cancer risk of up to 10(-6) and is the higher the more positive information exists regarding possible effects at critical toxic endpoints and for length of possible exposure. Past (historical) and present evaluations of "old" analytes were available in form of hundreds of HRGVs to count in 2 liters per day and person for 10% RSC or a 10(-6) non-threshold risk. These HRGVs were calculated by the present author either from ADI-, TDI- or RfD-values derived since 1993 by six large health authorities or they were identified directly at their websites or in the literature, always looking for confirmed or assumed worldwide relevance for drinking-water (resources). 36 of these up to 200 "old" analytes were ascribed since 1993 at least once an HRGV at or below 1 μg/l for (confirmed or provisionally assumed) "high" or "very high" threshold chronic toxicity. None but one of the corresponding 113 scientific HRGVs fell distinctly short of 0.3 μg/l. Only 14 carcinogens turned out as being relevant for drinking-water due to confirmed occurrence and coincident toxicological significance there. 13 of these exhibited a structural alert for genotoxicity. Ten of these 13 were "high-potency" genotoxic carcinogens with presently calculated non-threshold 10(-6) risk minimal HRGVs between 0.06 μg/l and 0.005 μg/l (9 compounds) or possibly down to 0.0007 μg/l (1 compound). This motivated UBA to propose a precautionary range between a minimal HRIV0=0.01 and a HRIV1=0.1 μg/l to assess new analytes bearing a structural alert for genotoxicity. The HRGVs for the remaining three (from 13) carcinogens with alerts for genotoxicity were at best similar for both genotoxic and non-genotoxic effects and higher or equal to 0.3 μg/l. Therefore, a minimal HRIV of 0.01 μg/l (HRIV0) or even 0.1 μg/l (HRIV1) would have appeared too low for assessing the presence in drinking-water of new analytes with no other human toxicity data than proven absence of both genotoxicity and of structural alerts for such. Instead, UBA proposes to provisionally assess such compounds by its next higher precautionary of HRIV3=0.3 μg/l. Any value once set is open for falsification upwards to either 1.0 μg/l (HRIV4) or 3.0 μg/l (HRIV5) or even for being replaced by an HRGV>3.0 μg/l if pertinent high toxicity effect potentials different from genotoxicity are similarly ruled out by either mechanistic and TTC-based arguments or a tiered experimental (in vitro and/or in vivo) approach. Regulatory-toxicological expertise gained since 1993 with "old" analytes in drinking-water (resources) and its extrapolation by analogy on new analytes with patchy human toxicological database allows for provisional assessment of their presence in drinking-water in form of five precautionary HRIVs. Selecting a HRIV, instead referring to a TTC or a virtually safe reference dose, just asks an expert judgment on the degree of formal completeness and informational potential of a new analyte's human toxicity database. Exceedance of a HRIV indicates need for supplementary toxicological data to improve assessment, their nature and comprehensiveness depending on degree and expected length of exceedance. The regulatory function of a HRIV is that of a placeholder for a possibly higher TTC-based surrogate HRGVTTC or a highest possible science-based HRGV. Copyright © 2013 Elsevier GmbH. All rights reserved.

An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Republican River Basin: 1997-1999

USGS Publications Warehouse

May, T.W.; Walther, M.J.; Petty, J.D.; Fairchild, J.F.; Lucero, J.; Delvaux, M.; Manring, J.; Armbruster, M.; Hartman, D.

2001-01-01

The Republican River Basin of Colorado,Nebraska, and Kansas lies in a valley which contains PierreShale as part of its geological substrata. Selenium is anindigenous constituent in the shale and is readily leached intosurrounding groundwater. The Basin is heavily irrigated throughthe pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water,sediment, benthic invertebrates, and/or fish were collected from46 sites in the Basin and were analyzed for selenium to determinethe potential for food-chain bioaccumulation, dietary toxicity,and reproductive effects of selenium in biota. Resultingselenium concentrations were compared to published guidelines orbiological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 μg L-1, which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3–5 μg L-1, constituting a moderate hazard. Selenium concentrations in sedimentindicated little to no hazard for selenium accumulation fromsediments into the benthic food chain. Ninety-five percent ofbenthic invertebrates collected exhibited selenium concentrationsexceeding 3 μg g-1, a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 μg g-1selenium, indicating a high potential for toxicity andreproductive effects. However, examination of weight profilesof various species of collected individual fish suggestedsuccessful recruitment in spite of selenium concentrations thatexceeded published biological effects thresholds for health andreproductive success. This finding suggested that universalapplication of published guidelines for selenium may beinappropriate or at least may need refinement for systems similarto the Republican River Basin. Additional research is needed todetermine the true impact of selenium on fish and wildliferesources in the Basin.

Genetic variance of tolerance and the toxicant threshold model.

PubMed

Tanaka, Yoshinari; Mano, Hiroyuki; Tatsuta, Haruki

2012-04-01

A statistical genetics method is presented for estimating the genetic variance (heritability) of tolerance to pollutants on the basis of a standard acute toxicity test conducted on several isofemale lines of cladoceran species. To analyze the genetic variance of tolerance in the case when the response is measured as a few discrete states (quantal endpoints), the authors attempted to apply the threshold character model in quantitative genetics to the threshold model separately developed in ecotoxicology. The integrated threshold model (toxicant threshold model) assumes that the response of a particular individual occurs at a threshold toxicant concentration and that the individual tolerance characterized by the individual's threshold value is determined by genetic and environmental factors. As a case study, the heritability of tolerance to p-nonylphenol in the cladoceran species Daphnia galeata was estimated by using the maximum likelihood method and nested analysis of variance (ANOVA). Broad-sense heritability was estimated to be 0.199 ± 0.112 by the maximum likelihood method and 0.184 ± 0.089 by ANOVA; both results implied that the species examined had the potential to acquire tolerance to this substance by evolutionary change. Copyright © 2012 SETAC.

The application of the diabetes prevention trial-type 1 risk score for identifying a preclinical state of type 1 diabetes.

PubMed

Sosenko, Jay M; Skyler, Jay S; Mahon, Jeffrey; Krischer, Jeffrey P; Beam, Craig A; Boulware, David C; Greenbaum, Carla J; Rafkin, Lisa E; Cowie, Catherine; Cuthbertson, David; Palmer, Jerry P

2012-07-01

We assessed the utility of the Diabetes Prevention Trial-Type 1 Risk Score (DPTRS) for identifying individuals who are highly likely to progress to type 1 diabetes (T1D) within 2 years. The DPTRS was previously developed from Diabetes Prevention Trial-Type 1 (DPT-1) data and was subsequently validated in the TrialNet Natural History Study (TNNHS). DPTRS components included C-peptide and glucose indexes from oral glucose tolerance testing, along with age and BMI. The cumulative incidence of T1D was determined after DPTRS thresholds were first exceeded and after the first occurrences of glucose abnormalities. The 2-year risks after the 9.00 DPTRS threshold was exceeded were 0.88 and 0.77 in DPT-1 (n = 90) and the TNNHS (n = 69), respectively. In DPT-1, the 2-year risks were much lower after dysglycemia first occurred (0.37; n = 306) and after a 2-h glucose value between 190 and 199 mg/dL was first reached (0.64; n = 59). Among those who developed T1D in DPT-1, the 9.00 threshold was exceeded 0.81 ± 0.53 years prior to the conventional diagnosis. Postchallenge C-peptide levels were substantially higher (P = 0.001 for 30 min; P < 0.001 for other time points) when the 9.00 threshold was first exceeded compared with the levels at diagnosis. A DPTRS threshold of 9.00 identifies individuals who are very highly likely to progress to the conventional diagnosis of T1D within 2 years and, thus, are essentially in a preclinical diabetic state. The 9.00 threshold is exceeded well before diagnosis, when stimulated C-peptide levels are substantially higher.

A survey of topsoil arsenic and mercury concentrations across France.

PubMed

Marchant, B P; Saby, N P A; Arrouays, D

2017-08-01

Even at low concentrations, the presence of arsenic and mercury in soils can lead to ecological and health impacts. The recent European-wide LUCAS Topsoil Survey found that the arsenic concentration of a large proportion of French soils exceeded a threshold which indicated that further investigation was required. A much smaller proportion of soils exceeded the corresponding threshold for mercury but the impacts of mining and industrial activities on mercury concentrations are not well understood. We use samples from the French national soil monitoring network (RMQS: Réseau de Mesures de la Qualité des Sols) to explore the variation of topsoil arsenic and mercury concentrations across mainland France at a finer spatial resolution than was reported by LUCAS Topsoil. We use geostatistical methods to map the expected concentrations of these elements in the topsoil and the probabilities that the legislative thresholds are exceeded. We find that, with the exception of some areas where the geogenic concentrations and soil adsorption capacities are very low, arsenic concentrations are generally larger than the threshold which indicates that further assessment of the area is required. The lower of two other guideline values indicating risks to ecology or health is exceeded in fewer than 5% of RMQS samples. These exceedances occur in localised hot-spots primarily associated with mining and mineralization. The probabilities of mercury concentrations exceeding the further assessment threshold value are everywhere less than 0.01 and none of the RMQS samples exceed either of the ecological and health risk thresholds. However, there are some regions with elevated concentrations which can be related to volcanic material, natural mineralizations and industrial contamination. These regions are more diffuse than the hot-spots of arsenic reflecting the greater volatility of mercury and therefore the greater ease with which it can be transported and redeposited. The maps provide a baseline against which future phases of the RMQS can be compared and highlight regions where the threat of soil contamination and its impacts should be more closely monitored. Copyright © 2017 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nedrich, Sara M.; Chappaz, Anthony; Hudson, Michelle L.

Effects of hydrologic variability on reservoir biogeochemistry are relatively unknown, particularly for less studied metals like vanadium (V). Further, few studies have investigated the fate and effects of sediment-associated V to aquatic organisms in hydrologically variable systems. Our primary objective was to assess effects of hydrologic manipulation on speciation and toxicity of V (range: 635 to 1620 mg kg- 1) and other metals to Hyalella azteca and Daphnia magna. Sediments were collected from a reservoir located in a former mining area and microcosm experiments were conducted to emulate 7-day drying and inundation periods. Despite high sediment concentrations, V bioavailability remainedmore » low with no significant effects to organism survival, growth, or reproduction. The lack of V toxicity was attributed to reduced speciation (III, IV), non-labile complexation, and sorption to Al/Fe/Mn-oxyhydroxides. Zinc (Zn) increased in surface and porewater with inundation, for some sediments exceeding the U.S. EPA threshold for chronic toxicity. While no effects of Zn to organism survival or growth were observed, Zn body concentrations were negatively correlated with H. azteca growth. Results from this study indicate that V bioavailability and environmental risk is dependent on V-speciation, and V is less influenced by hydrologic variability than more labile metals such as Zn.« less

PAHs sensitivity of picophytoplankton populations in the Red Sea.

PubMed

Kottuparambil, Sreejith; Agusti, Susana

2018-04-25

In this study, we investigated the in situ responses of Red Sea picophytoplankton, the dominant phytoplankton group in the oligotrophic ocean, to two toxic polycyclic aromatic hydrocarbons (PAHs), phenanthrene and pyrene. The experiments were conducted across a latitudinal gradient of the Saudi Arabian Red Sea, an area sensitive to oil pollution. We observed significant adverse effects on the growth and abundance of the picocyanobacteria Synechococcus and picoeukaryotes, at all stations sampled. Prochlorococcus, which was abundant only at one of the stations, also appeared to be affected. Pyrene was found to be more toxic to phytoplankton at all stations. In general, picoeukaryotes exhibited higher sensitivity to PAHs than Synechococcus. Populations in the highly oligotrophic Northern region of the Red Sea were more tolerant to PAHs, presumably influenced by the natural selection of more resistant strains of phytoplankton due to the prolonged exposure to PAHs. Toxicity threshold values estimated here are higher than those reported for picophytoplankton from other oligotrophic marine waters and exceed by far the natural levels of PAHs in many oceans. Our findings reveal a possible adaptation of picophytoplankton populations to oil-related contaminants, which may clearly influence their spatial distribution patterns in the Red Sea. Copyright © 2018 Elsevier Ltd. All rights reserved.

Selection of a battery of rapid toxicity sensors for drinking water evaluation.

PubMed

van der Schalie, William H; James, Ryan R; Gargan, Thomas P

2006-07-15

Comprehensive identification of chemical contaminants in Army field water supplies can be a lengthy process, but rapid analytical methods suitable for field use are limited. A complementary approach is to directly measure toxicity instead of individual chemical constituents. Ten toxicity sensors utilizing enzymes, bacteria, or vertebrate cells were tested to determine the minimum number of sensors that could rapidly identify toxicity in water samples containing one of 12 industrial chemicals. The ideal sensor would respond at a concentration just exceeding the Military Exposure Guideline (MEG) level for the chemical (an estimated threshold for adverse effects) but below the human lethal concentration. Chemical solutions were provided to testing laboratories as blind samples. No sensors responded to deionized water blanks, and only one sensor responded to a hard water blank. No single toxicity sensor responded to more than six chemicals in the desired response range, and one chemical (nicotine) was not detected by any sensor with the desired sensitivity. A combination of three sensors (Microtox, the Electric Cell Substrate Impedance Sensing (ECIS) test, and the Hepatocyte low density lipoprotein (LDL) uptake test) responded appropriately to nine of twelve chemicals. Adding a fourth sensor (neuronal microelectrode array) to the test battery allowed detection of two additional chemicals (aldicarb and methamidophos), but the neuronal microelectrode array was overly sensitive to paraquat. Evaluating sensor performance using a standard set of chemicals and a desired sensitivity range provides a basis both for selecting among available toxicity sensors and for evaluating emerging sensor technologies. Recommendations for future toxicity sensor evaluations are discussed.

48 CFR 36.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 36.602-5 Section 36.602-5 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 36.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 36.602-5 Section 36.602-5 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1336.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1336.602-5 Section 1336.602-5 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 836.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 836.602-5 Section 836.602-5 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 636.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 636.602-5 Section 636.602-5 Federal Acquisition Regulations System DEPARTMENT OF STATE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 436.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 436.602-5 Section 436.602-5 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1436.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 1436.602-5 Section 1436.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

16 CFR 802.21 - Acquisitions of voting securities not meeting or exceeding greater notification threshold (as...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Acquisitions of voting securities not meeting or exceeding greater notification threshold (as adjusted). 802.21 Section 802.21 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976...

48 CFR 736.602-5 - Short selection process for procurements not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Short selection process for procurements not to exceed the simplified acquisition threshold. 736.602-5 Section 736.602-5 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACT...

48 CFR 1336.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1336.602-5 Section 1336.602-5 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 636.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 636.602-5 Section 636.602-5 Federal Acquisition Regulations System DEPARTMENT OF STATE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1036.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1036.602-5 Section 1036.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE TREASURY SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 436.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 436.602-5 Section 436.602-5 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 436.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 436.602-5 Section 436.602-5 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1436.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 1436.602-5 Section 1436.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 736.602-5 - Short selection process for procurements not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Short selection process for procurements not to exceed the simplified acquisition threshold. 736.602-5 Section 736.602-5 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACT...

48 CFR 436.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 436.602-5 Section 436.602-5 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 836.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 836.602-5 Section 836.602-5 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1336.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1336.602-5 Section 1336.602-5 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 36.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 36.602-5 Section 36.602-5 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 836.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 836.602-5 Section 836.602-5 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1336.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1336.602-5 Section 1336.602-5 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1436.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 1436.602-5 Section 1436.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 636.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 636.602-5 Section 636.602-5 Federal Acquisition Regulations System DEPARTMENT OF STATE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 36.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 36.602-5 Section 36.602-5 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

16 CFR 802.21 - Acquisitions of voting securities not meeting or exceeding greater notification threshold (as...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Acquisitions of voting securities not meeting or exceeding greater notification threshold (as adjusted). 802.21 Section 802.21 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976...

48 CFR 736.602-5 - Short selection process for procurements not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Short selection process for procurements not to exceed the simplified acquisition threshold. 736.602-5 Section 736.602-5 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACT...

48 CFR 1036.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1036.602-5 Section 1036.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE TREASURY SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 36.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 36.602-5 Section 36.602-5 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1036.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1036.602-5 Section 1036.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE TREASURY SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1036.602-5 - Short selection process for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Short selection process for contracts not to exceed the simplified acquisition threshold. 1036.602-5 Section 1036.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE TREASURY SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 1436.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 1436.602-5 Section 1436.602-5 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

48 CFR 636.602-5 - Short selection processes for contracts not to exceed the simplified acquisition threshold.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Short selection processes for contracts not to exceed the simplified acquisition threshold. 636.602-5 Section 636.602-5 Federal Acquisition Regulations System DEPARTMENT OF STATE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS...

Mercury in Forage Fish from Mexico and Central America: Implications for Fish-Eating Birds.

PubMed

Elliott, John E; Kirk, David A; Elliott, Kyle H; Dorzinsky, Jessica; Lee, Sandi; Inzunza, Ernesto Ruelas; Cheng, Kimberly M T; Scheuhammer, Tony; Shaw, Patrick

2015-11-01

Mercury (Hg) is a global contaminant of aquatic food chains. Aquatic birds, such as the osprey (Pandion haliaetus), with migratory populations breeding in Canada and the northern United States and wintering in the Central and South America, can be exposed to mercury on both the breeding and wintering ranges. We examined Hg levels in 14 fish taxa from 24 osprey wintering sites identified from satellite telemetry. Our main goal was to determine whether fish species that feature in the diet of overwintering and resident fish-eating birds reached toxicity thresholds for Hg. Mean Hg levels in fish whole carcasses ranged from a high of 0.18 µg g(-1) (wet weight) in Scomberomorus sierra to a low of 0.009 µg g(-1) in Catostomidae. Average Hg levels were within published toxicity threshold values in forage fish for only two sites in Mexico (Puerto Vallarta and San Blas Estuary), and all were marine species, such as mackerel (Scomberomorus sierra), sea catfish (Ariopus spp.), and sardinas species (Centropomus spp.). Except for one sample from Nicaragua, sea catfish from Puerto Morazan, none of the fish from sites in Central America had Hg levels which exceeded the thresholds. Nonmetric multidimensional scaling revealed geographical differences in Hg levels with significant pairwise differences between sites along the Pacific Ocean (Mexico) versus the Bay of Campeche, partly due to differences in species composition of sampled fish (and species distributions). Hg increased with trophic level, as assessed by nitrogen stable isotope ratios (δ(15)N but not δ(13)C), in freshwater and marine, but not estuarine, environments. Hg concentrations in forage fish do not account for the elevated Hg reported for many osprey populations on the breeding grounds, thus primary sources of contamination appear to be in the north.

Scaling of Precipitation Extremes Modelled by Generalized Pareto Distribution

NASA Astrophysics Data System (ADS)

Rajulapati, C. R.; Mujumdar, P. P.

2017-12-01

Precipitation extremes are often modelled with data from annual maximum series or peaks over threshold series. The Generalized Pareto Distribution (GPD) is commonly used to fit the peaks over threshold series. Scaling of precipitation extremes from larger time scales to smaller time scales when the extremes are modelled with the GPD is burdened with difficulties arising from varying thresholds for different durations. In this study, the scale invariance theory is used to develop a disaggregation model for precipitation extremes exceeding specified thresholds. A scaling relationship is developed for a range of thresholds obtained from a set of quantiles of non-zero precipitation of different durations. The GPD parameters and exceedance rate parameters are modelled by the Bayesian approach and the uncertainty in scaling exponent is quantified. A quantile based modification in the scaling relationship is proposed for obtaining the varying thresholds and exceedance rate parameters for shorter durations. The disaggregation model is applied to precipitation datasets of Berlin City, Germany and Bangalore City, India. From both the applications, it is observed that the uncertainty in the scaling exponent has a considerable effect on uncertainty in scaled parameters and return levels of shorter durations.

2006 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ecology and Air Quality Group

2007-12-12

For reporting year 2006, Los Alamos National Laboratory (LANL or the Laboratory) submitted Form R reports for lead as required under the Emergency Planning and Community Right-to-Know Act (EPCRA) Section 313. No other EPCRA Section 313 chemicals were used in 2006 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2006, as well as to provide background information about data included on the Form R reports. Section 313 of EPCRA specifically requires facilities to submit a Toxic Chemical Release Inventorymore » Report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. In 1999, EPA promulgated a final rule on persistent bioaccumulative toxics (PBTs). This rule added several chemicals to the EPCRA Section 313 list of toxic chemicals and established lower reporting thresholds for these and other PBT chemicals that were already reportable. These lower thresholds became applicable in reporting year 2000. In 2001, EPA expanded the PBT rule to include a lower reporting threshold for lead and lead compounds. Facilities that manufacture, process, or otherwise use more than 100 lb of lead or lead compounds must submit a Form R.« less

Development of Thresholds and Exceedance Probabilities for Influent Water Quality to Meet Drinking Water Regulations

NASA Astrophysics Data System (ADS)

Reeves, K. L.; Samson, C.; Summers, R. S.; Balaji, R.

2017-12-01

Drinking water treatment utilities (DWTU) are tasked with the challenge of meeting disinfection and disinfection byproduct (DBP) regulations to provide safe, reliable drinking water under changing climate and land surface characteristics. DBPs form in drinking water when disinfectants, commonly chlorine, react with organic matter as measured by total organic carbon (TOC), and physical removal of pathogen microorganisms are achieved by filtration and monitored by turbidity removal. Turbidity and TOC in influent waters to DWTUs are expected to increase due to variable climate and more frequent fires and droughts. Traditional methods for forecasting turbidity and TOC require catchment specific data (i.e. streamflow) and have difficulties predicting them under non-stationary climate. A modelling framework was developed to assist DWTUs with assessing their risk for future compliance with disinfection and DBP regulations under changing climate. A local polynomial method was developed to predict surface water TOC using climate data collected from NOAA, Normalized Difference Vegetation Index (NDVI) data from the IRI Data Library, and historical TOC data from three DWTUs in diverse geographic locations. Characteristics from the DWTUs were used in the EPA Water Treatment Plant model to determine thresholds for influent TOC that resulted in DBP concentrations within compliance. Lastly, extreme value theory was used to predict probabilities of threshold exceedances under the current climate. Results from the utilities were used to produce a generalized TOC threshold approach that only requires water temperature and bromide concentration. The threshold exceedance model will be used to estimate probabilities of exceedances under projected climate scenarios. Initial results show that TOC can be forecasted using widely available data via statistical methods, where temperature, precipitation, Palmer Drought Severity Index, and NDVI with various lags were shown to be important predictors of TOC, and TOC thresholds can be determined using water temperature and bromide concentration. Results include a model to predict influent turbidity and turbidity thresholds, similar to the TOC models, as well as probabilities of threshold exceedances for TOC and turbidity under changing climate.

41 CFR 102-73.40 - What happens if the dollar value of the project exceeds the prospectus threshold?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 false What happens if the dollar value of the project exceeds the prospectus threshold? 102-73.40 Section 102-73.40 Public Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 73-REAL ESTATE...

41 CFR 102-73.40 - What happens if the dollar value of the project exceeds the prospectus threshold?

Code of Federal Regulations, 2014 CFR

2014-01-01

... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 false What happens if the dollar value of the project exceeds the prospectus threshold? 102-73.40 Section 102-73.40 Public Contracts and Property Management Federal Property Management Regulations System (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 73-REAL ESTATE...

Determination of total vanadium and vanadium(V) in groundwater from Mt. Etna and estimate of daily intake of vanadium(V) through drinking water.

PubMed

Arena, Giovanni; Copat, Chiara; Dimartino, Angela; Grasso, Alfina; Fallico, Roberto; Sciacca, Salvatore; Fiore, Maria; Ferrante, Margherita

2015-06-01

Vanadium(V) can be found in natural waters in the form of V(IV) and V(V) species, which have different biological properties and toxicity. The purpose of this study was to determine the concentrations of total V and V(V) in groundwater from the area of Mt. Etna and to assess the estimated daily intake (EDI) of V(V) of adults and children through drinking water. Water was sampled monthly at 21 sites in 2011. Total vanadium was determined by inductively coupled plasma-mass spectrometry (ICP-MS) and speciation by ion chromatography-ICP-MS (IC-ICP-MS). The concentration of V(V) species ranged from 62.8 to 98.9% of total V, with significantly higher concentrations in samples from the S/SW slope of Mt. Etna. The annual mean concentrations of total V exceeded the Italian legal limit of 140 μg/L at four sites on the S/SW slope. In the absence of thresholds for V(V) intake, only the Environmental Protection Agency (EPA) has calculated a reference dose. Children's EDI of V(V) at the sites with the higher V concentrations exceeded EPA thresholds (9 μg/kg/day). In particular, we found in Camporotondo, Mascalucia, Ragalna and San Pietro Clarenza sites children's EDIs of 11, 9.3, 11 and 9.9, respectively. The EDI of V(V) was significantly higher than the literature range (0.09-0.34 μg/kg/day).

Importance of the pre-industrial baseline for likelihood of exceeding Paris goals

NASA Astrophysics Data System (ADS)

Schurer, Andrew P.; Mann, Michael E.; Hawkins, Ed; Tett, Simon F. B.; Hegerl, Gabriele C.

2017-08-01

During the Paris conference in 2015, nations of the world strengthened the United Nations Framework Convention on Climate Change by agreeing to holding `the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C' (ref. ). However, `pre-industrial' was not defined. Here we investigate the implications of different choices of the pre-industrial baseline on the likelihood of exceeding these two temperature thresholds. We find that for the strongest mitigation scenario RCP2.6 and a medium scenario RCP4.5, the probability of exceeding the thresholds and timing of exceedance is highly dependent on the pre-industrial baseline; for example, the probability of crossing 1.5 °C by the end of the century under RCP2.6 varies from 61% to 88% depending on how the baseline is defined. In contrast, in the scenario with no mitigation, RCP8.5, both thresholds will almost certainly be exceeded by the middle of the century with the definition of the pre-industrial baseline of less importance. Allowable carbon emissions for threshold stabilization are similarly highly dependent on the pre-industrial baseline. For stabilization at 2 °C, allowable emissions decrease by as much as 40% when earlier than nineteenth-century climates are considered as a baseline.

48 CFR 529.401-70 - Purchases at or under the simplified acquisition threshold.

Code of Federal Regulations, 2012 CFR

2012-10-01

... simplified acquisition threshold. 529.401-70 Section 529.401-70 Federal Acquisition Regulations System... Purchases at or under the simplified acquisition threshold. Insert 552.229-70, Federal, State, and Local Taxes, in purchases and contracts estimated to exceed the micropurchase threshold, but not the...

First Report of a Toxic Nodularia spumigena (Nostocales/ Cyanobacteria) Bloom in Sub-Tropical Australia. I. Phycological and Public Health Investigations

PubMed Central

McGregor, Glenn B.; Stewart, Ian; Sendall, Barbara C.; Sadler, Ross; Reardon, Karen; Carter, Steven; Wruck, Dan; Wickramasinghe, Wasa

2012-01-01

Cyanobacterial blooms represent one of the most conspicuous and widespread waterborne microbial hazards to human and ecosystem health. Investigation of a cyanobacterial bloom in a shallow brackish water recreational cable ski lake in south-eastern Queensland, Australia revealed the dominance of the toxigenic species Nodularia spumigena. The bloom spanned three months, during which time cell concentrations exceeded human guideline thresholds for recreational risk, and concentrations of the hepatotoxic cyanotoxin nodularin exceeded 200 µg L−1. Cyanotoxin origin and identification was confirmed by amplification of the ndaF-specific PCR product and sequencing of the 16S rRNA gene. From the limited data available leading up to, and throughout the bloom, it was not possible to establish the set of causative factors responsible for its occurrence. However a combination of factors including salinity, hydraulic retention time and nutrient status associated with an extended period of drought are likely to have contributed. This was the first known occurrence of this species in bloom proportions from sub-tropical Australia and as such represents a hitherto uncharacterized risk to human and ecosystem health. It highlights the need for adaptive monitoring regimes to ensure a comprehensive understanding of the potentially toxic cyanobacteria likely to inhabit any given region. Such monitoring needs to recognize that cyanobacteria have a significant capacity for range expansion that has been facilitated by recent changes in global climate. PMID:22851951

Evaluating the Spatial Distribution of Toxic Air Contaminants in Multiple Ecosystem Indicators in the Sierra Nevada-Southern Cascades

NASA Astrophysics Data System (ADS)

Nanus, L.; Simonich, S. L.; Rocchio, J.; Flanagan, C.

2013-12-01

Toxic air contaminants originating from agricultural areas of the Central Valley in California threaten vulnerable sensitive receptors including surface water, vegetation, snow, sediments, fish, and amphibians in the Sierra Nevada-Southern Cascades region. The spatial distribution of toxic air contaminants in different ecosystem indicators depends on variation in atmospheric concentrations and deposition, and variation in air toxics accumulation in ecosystems. The spatial distribution of organic air toxics and mercury at over 330 unique sampling locations and sample types over two decades (1990-2009) in the Sierra Nevada-Southern Cascades region were compiled and maps were developed to further understand spatial patterns and linkages between air toxics deposition and ecological effects. Potential ecosystem impacts in the Sierra Nevada-Southern Cascades region include bioaccumulation of air toxics in both aquatic and terrestrial ecosystems, reproductive disruption, and immune suppression. The most sensitive ecological end points in the region that are affected by bioaccumulation of toxic air contaminants are fish. Mercury was detected in all fish and approximately 6% exceeded human consumption thresholds. Organic air toxics were also detected in fish yielding variable spatial patterns. For amphibians, which are sensitive to pesticide exposure and potential immune suppression, increasing trends in current and historic use pesticides are observed from north to south across the region. In other indicators, such as vegetation, pesticide concentrations in lichen increase with increasing elevation. Current and historic use pesticides and mercury were also observed in snowpack at high elevations in the study area. This study shows spatial patterns in toxic air contaminants, evaluates associated risks to sensitive receptors, and identifies data gaps. Future research on atmospheric modeling and information on sources is needed in order to predict which ecosystems are the most sensitive to toxic air contaminants in the Sierra Nevada-Southern Cascades region.

Barrage fishponds: Reduction of pesticide concentration peaks and associated risk of adverse ecological effects in headwater streams.

PubMed

Gaillard, Juliette; Thomas, Marielle; Iuretig, Alain; Pallez, Christelle; Feidt, Cyril; Dauchy, Xavier; Banas, Damien

2016-03-15

Constructed wetlands have been suggested as pesticide risk mitigation measures. Yet, in many agricultural areas, ponds or shallow lakes are already present and may contribute to the control of non-point source contamination by pesticides. In order to test this hypothesis, we investigated the influence of extensively managed barrage fishponds (n = 3) on the dissolved concentrations of 100 pesticides in headwater streams over the course of a year. Among the 100 pesticides, 50 different substances were detected upstream and 48 downstream. Highest measured concentration upstream was 26.5 μg/L (2-methyl-4-chlorophenoxyacetic acid, MCPA) and 5.19 μg/L (isoproturon) downstream. Fishponds were found to reduce peak exposure levels as high pesticide concentrations (defined here as ≥ 1 μg/L) generally decreased by more than 90% between upstream and downstream sampling sites. The measured concentrations in the investigated streams were compared to laboratory toxicity data for standard test organisms (algae, invertebrates and fish) using the toxic unit approach. When considering the threshold levels set by the European Union within the first tier risk assessment procedure for pesticide registration (commission regulation (EU) N° 546/2011), regulatory threshold exceedances were observed for 22 pesticides upstream from fishponds and for 9 pesticides downstream. Therefore, the investigated barrage fishponds contributed to the reduction of pesticide peak concentrations and potential risk of adverse effects for downstream ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cyanotoxins in inland lakes of the United States: Occurrence and potential recreational health risks in the EPA National Lakes Assessment 2007

USGS Publications Warehouse

Loftin, Keith A.; Graham, Jennifer L.; Elizabeth Hilborn,; Sarah Lehmann,; Meyer, Michael T.; Dietze, Julie E.; Griffith, Christopher

2016-01-01

A large nation-wide survey of cyanotoxins (1161 lakes) in the United States (U.S.) was conducted during the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse toxicity data to evaluate potential recreational risks. Cylindrospermopsins, microcystins, and saxitoxins were detected (ELISA) in 4.0, 32, and 7.7% of samples with mean concentrations of 0.56, 3.0, and 0.061 mg/L, respectively (detections only). Co-occurrence of the three cyanotoxin classes was rare (0.32%) when at least one toxin was detected. Cyanobacteria were present and dominant in 98 and 76% of samples, respectively. Potential anatoxin-, cylindrospermopsin-, microcystin-, and saxitoxin-producing cyanobacteria occurred in 81, 67, 95, and 79% of samples, respectively. Anatoxin-a and nodularin-R were detected (LC/MS/MS) in 15 and 3.7% samples (n = 27). The WHO moderate and high risk thresholds for microcystins, cyanobacteria abundance, and total chlorophyll were exceeded in 1.1, 27, and 44% of samples, respectively. Complete agreement by all three WHO microcystin metrics occurred in 27% of samples. This suggests that WHO microcystin metrics based on total chlorophyll and cyanobacterial abundance can overestimate microcystin risk when compared to WHO microcystin thresholds. The lack of parity among the WHO thresholds was expected since chlorophyll is common amongst all phytoplankton and not all cyanobacteria produce microcystins.

Identifying a rainfall event threshold triggering herbicide leaching by preferential flow

NASA Astrophysics Data System (ADS)

McGrath, G. S.; Hinz, C.; Sivapalan, M.; Dressel, J.; Pütz, T.; Vereecken, H.

2010-02-01

How can leaching risk be assessed if the chemical flux and/or the toxicity is highly uncertain? For many strongly sorbing pesticides it is known that their transport through the unsaturated zone occurs intermittently through preferential flow, triggered by significant rainfall events. In these circumstances the timing and frequency of these rainfall events may allow quantification of leaching risk to overcome the limitations of flux prediction. In this paper we analyze the leaching behavior of bromide and two herbicides, methabenzthiazuron and ethidimuron, using data from twelve uncropped lysimeters, with high-resolution climate data, in order to identify the rainfall controls on rapid solute leaching. A regression tree analysis suggested that a coarse-scale fortnightly to monthly water balance was a good predictor of short-term increases in drainage and bromide transport. Significant short-term herbicide leaching, however, was better predicted by the occurrence of a single storm with a depth greater than a 19 mm threshold. Sampling periods where rain events exceeded this threshold accounted for between 38% and 56% of the total mass of herbicides leached during the experiment. The same threshold only accounted for between 1% and 10% of the total mass of bromide leached. On the basis of these results, we conclude that in this system, the leaching risks of strongly sorbing chemicals can be quantified by the timing and frequency of these large rainfall events. Empirical and modeling approaches are suggested to apply this frequentist approach to leaching risk assessment to other soil-climate systems.

Cyanotoxins in inland lakes of the United States: Occurrence and potential recreational health risks in the EPA National Lakes Assessment 2007.

PubMed

Loftin, Keith A; Graham, Jennifer L; Hilborn, Elizabeth D; Lehmann, Sarah C; Meyer, Michael T; Dietze, Julie E; Griffith, Christopher B

2016-06-01

A large nation-wide survey of cyanotoxins (1161 lakes) in the United States (U.S.) was conducted during the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse toxicity data to evaluate potential recreational risks. Cylindrospermopsins, microcystins, and saxitoxins were detected (ELISA) in 4.0, 32, and 7.7% of samples with mean concentrations of 0.56, 3.0, and 0.061μg/L, respectively (detections only). Co-occurrence of the three cyanotoxin classes was rare (0.32%) when at least one toxin was detected. Cyanobacteria were present and dominant in 98 and 76% of samples, respectively. Potential anatoxin-, cylindrospermopsin-, microcystin-, and saxitoxin-producing cyanobacteria occurred in 81, 67, 95, and 79% of samples, respectively. Anatoxin-a and nodularin-R were detected (LC/MS/MS) in 15 and 3.7% samples (n=27). The WHO moderate and high risk thresholds for microcystins, cyanobacteria abundance, and total chlorophyll were exceeded in 1.1, 27, and 44% of samples, respectively. Complete agreement by all three WHO microcystin metrics occurred in 27% of samples. This suggests that WHO microcystin metrics based on total chlorophyll and cyanobacterial abundance can overestimate microcystin risk when compared to WHO microcystin thresholds. The lack of parity among the WHO thresholds was expected since chlorophyll is common amongst all phytoplankton and not all cyanobacteria produce microcystins. Published by Elsevier B.V.

A Queueing Approach to Optimal Resource Replication in Wireless Sensor Networks

DTIC Science & Technology

2009-04-29

network (an energy- centric approach) or to ensure the proportion of query failures does not exceed a predetermined threshold (a failure- centric ...replication strategies in wireless sensor networks. The model can be used to minimize either the total transmission rate of the network (an energy- centric ...approach) or to ensure the proportion of query failures does not exceed a predetermined threshold (a failure- centric approach). The model explicitly

Ecological risk assessment of a coastal zone in Southern Vietnam: Spatial distribution and content of heavy metals in water and surface sediments of the Thi Vai Estuary and Can Gio Mangrove Forest.

PubMed

Costa-Böddeker, Sandra; Hoelzmann, Philipp; Thuyên, Lê Xuân; Huy, Hoang Duc; Nguyen, Hoang Anh; Richter, Otto; Schwalb, Antje

2017-01-30

Enrichment of heavy metals was assessed in the Thi Vai Estuary and in the Can Gio Mangrove Forest (SE, Vietnam). Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn contents in water and in sediments were measured. Total organic carbon, nitrogen, phosphorus and C/N ratios were determined. Cu and Cr values were higher than threshold effect level of toxicity, while Ni exceeded probable effect level, indicating the risk of probable toxicity effects. Enrichment factors (EF), contamination factor (CF) and Geo-accumulation index (I-geo) were determined. CF reveals moderate to considerable pollution with Cr and Ni. EF suggests anthropogenic sources of Cr, Cu and Ni. I-geo indicates low contamination with Co, Cu and Zn and moderate contamination with Cr and Ni. Overall metal contents were lower than expected for this highly industrialized region, probably due to dilution, suggesting that erosion rates and hydrodynamics may also play a role in metal contents distribution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Environmental contaminants and biomarker responses in fish from the Columbia River and its tributaries: spatial and temporal trends

USGS Publications Warehouse

Hinck, J.E.; Schmitt, C.J.; Blazer, V.S.; Denslow, N.D.; Bartish, T.M.; Anderson, P.J.; Coyle, J.J.; Dethloff, G.M.; Tillitt, D.E.

2006-01-01

Fish were collected from 16 sites on rivers in the Columbia River Basin (CRB) from September 1997 to April 1998 to document temporal and spatial trends in the concentrations of accumulative contaminants and to assess contaminant effects on the fish. Sites were located on the mainstem of the Columbia River and on the Snake, Willamette, Yakima, Salmon, and Flathead Rivers. Common carp (Cyprinus carpio), black bass (Micropterus sp.), and largescale sucker (Catostomus macrocheilus) were the targeted species. Fish were field-examined for external and internal lesions, selected organs were weighed to compute somatic indices, and tissue and fluid samples were preserved for fish health and reproductive biomarker analyses. Composite samples of whole fish, grouped by species and gender, from each site were analyzed for organochlorine and elemental contaminants using instrumental methods and for 2,3,7,8-tetrachloro dibenzo-p-dioxin-like activity (TCDD-EQ) using the H4IIE rat hepatoma cell bioassay. Overall, pesticide concentrations were greatest in fish from lower CRB sites and elemental concentrations were greatest in fish from upper CRB sites. These patterns reflected land uses. Lead (Pb) concentrations in fish from the Columbia River at Northport and Grand Coulee, Washington (WA) exceeded fish and wildlife toxicity thresholds (> 0.4 ??g/g). Selenium (Se) concentrations in fish from the Salmon River at Riggins, Idaho (ID), the Columbia River at Vernita Bridge, WA, and the Yakima River at Granger, WA exceeded toxicity thresholds for piscivorous wildlife (> 0.6 ??g/g). Mercury (Hg) concentrations in fish were elevated throughout the basin but were greatest (> 0.4 ??g/g) in predatory fish from the Salmon River at Riggins, ID, the Yakima River at Granger, WA, and the Columbia River at Warrendale, Oregon (OR). Residues of p,p???-DDE were greatest (> 0.8 ??g/g) in fish from agricultural areas of the Snake, Yakima, and Columbia River basins but were not detected in upper CRB fish. Other organochlorine pesticides did not exceed toxicity thresholds in fish or were detected infrequently. Total polychlorinated biphenyls (PCBs; > 0.11 ??g/g) and TCDD-EQs (> 5 pg/g) exceeded wildlife guidelines in fish from the middle and lower CRB, and ethoxyresorufin O-deethylase (EROD) activity was also elevated at many of the same sites. Temporal trend analysis indicated decreasing or stable concentrations of Pb, Se, Hg, p,p???-DDE, and PCBs at most sites where historical data were available. Altered biomarkers were noted in fish throughout the CRB. Fish from some stations had responded to chronic contaminant exposure as indicated by fish health and reproductive biomarker results. Although most fish from some sites had grossly visible external or internal lesions, histopathological analysis determined these to be inflammatory responses associated with helminth or myxosporidian parasites. Many largescale sucker from the Columbia River at Northport and Grand Coulee, WA had external lesions and enlarged spleens, which were likely associated with infections. Intersex male smallmouth bass (Micropterus dolomieu) were found in the Snake River at Lewiston, ID and the Columbia River at Warrendale, OR. Male bass, carp, and largescale sucker containing low concentrations of vitellogenin were common in the CRB, and comparatively high concentrations (> 0.3 mg/mL) were measured in male fish from the Flathead River at Creston, Montana, the Snake River at Ice Harbor Dam, WA, and the Columbia River at Vernita Bridge, WA and Warrendale, OR. Results from our study and other investigations indicate that continued monitoring in the CRB is warranted to identify consistently degraded sites and those with emerging problems. ?? 2005 Elsevier B.V. All rights reserved.

Assessment of trace metals contamination level, bioavailability and toxicity in sediments from Dakar coast and Saint Louis estuary in Senegal, West Africa.

PubMed

Diop, Cheikh; Dewaelé, Dorothée; Cazier, Fabrice; Diouf, Amadou; Ouddane, Baghdad

2015-11-01

Trace metals have the potential to associate with sediments that have been recognised as significant source of contamination for the benthic environment. The current study aims assessing the trace metals contamination level in sediments from Dakar coast and Saint Louis estuary, and to examine their bioavailability to predict potential toxicity of sediments. Surface sediment samples were collected between June 2012 and January 2013 in three sampling periods from eight stations. Trace metals were analysed using inductively coupled plasma-optical emission spectrometer. Geoaccumulation indexes (Igeo) showed strong pollution by Cd, Cr, Cu and Pb confirmed by enrichment factor (EF) suggesting that these metals derived from anthropogenic sources. Toxicity indexes exceeded one in several sites suggesting the potential effects on sediment-dwelling organisms, which may constitute a risk to populations' health. However, seasonal variability of metal bioavailability was noted, revealing the best period to monitor metal contamination. From an ecotoxicological point of view, concentrations of Cd, Cr, Cu and Pb were above the effects range low threshold limit of the sediment quality guidelines for adverse biological effects. In addition, with Pb concentrations above the effect range medium values in some sites, biological effects may occur. Copyright © 2014 Elsevier Ltd. All rights reserved.

PCB pollution continues to impact populations of orcas and other dolphins in European waters

NASA Astrophysics Data System (ADS)

Jepson, Paul D.; Deaville, Rob; Barber, Jonathan L.; Aguilar, Àlex; Borrell, Asunción; Murphy, Sinéad; Barry, Jon; Brownlow, Andrew; Barnett, James; Berrow, Simon; Cunningham, Andrew A.; Davison, Nicholas J.; Ten Doeschate, Mariel; Esteban, Ruth; Ferreira, Marisa; Foote, Andrew D.; Genov, Tilen; Giménez, Joan; Loveridge, Jan; Llavona, Ángela; Martin, Vidal; Maxwell, David L.; Papachlimitzou, Alexandra; Penrose, Rod; Perkins, Matthew W.; Smith, Brian; de Stephanis, Renaud; Tregenza, Nick; Verborgh, Philippe; Fernandez, Antonio; Law, Robin J.

2016-01-01

Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well-established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n = 929) or biopsied (n = 152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB “hotspots” for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas.

PCB pollution continues to impact populations of orcas and other dolphins in European waters.

PubMed

Jepson, Paul D; Deaville, Rob; Barber, Jonathan L; Aguilar, Àlex; Borrell, Asunción; Murphy, Sinéad; Barry, Jon; Brownlow, Andrew; Barnett, James; Berrow, Simon; Cunningham, Andrew A; Davison, Nicholas J; Ten Doeschate, Mariel; Esteban, Ruth; Ferreira, Marisa; Foote, Andrew D; Genov, Tilen; Giménez, Joan; Loveridge, Jan; Llavona, Ángela; Martin, Vidal; Maxwell, David L; Papachlimitzou, Alexandra; Penrose, Rod; Perkins, Matthew W; Smith, Brian; de Stephanis, Renaud; Tregenza, Nick; Verborgh, Philippe; Fernandez, Antonio; Law, Robin J

2016-01-14

Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well-established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n = 929) or biopsied (n = 152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB "hotspots" for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas.

PCB pollution continues to impact populations of orcas and other dolphins in European waters

PubMed Central

Jepson, Paul D.; Deaville, Rob; Barber, Jonathan L.; Aguilar, Àlex; Borrell, Asunción; Murphy, Sinéad; Barry, Jon; Brownlow, Andrew; Barnett, James; Berrow, Simon; Cunningham, Andrew A.; Davison, Nicholas J.; ten Doeschate, Mariel; Esteban, Ruth; Ferreira, Marisa; Foote, Andrew D.; Genov, Tilen; Giménez, Joan; Loveridge, Jan; Llavona, Ángela; Martin, Vidal; Maxwell, David L.; Papachlimitzou, Alexandra; Penrose, Rod; Perkins, Matthew W.; Smith, Brian; de Stephanis, Renaud; Tregenza, Nick; Verborgh, Philippe; Fernandez, Antonio; Law, Robin J.

2016-01-01

Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well-established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n = 929) or biopsied (n = 152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB “hotspots” for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas. PMID:26766430

2002 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Stockton

2003-11-01

For reporting year 2002, Los Alamos National Laboratory (LANL or the Laboratory) submitted Form R reports for lead compounds and mercury as required under the Emergency Planning and Community Right-to-Know Act (EPCRA), Section 313. No other EPCRA Section 313 chemicals were used in 2002 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical usage and threshold determinations for LANL for calendar year 2002 as well as provide background information about the data included on the Form R reports. Section 313 of EPCRA specifically requires facilities to submit a Toxicmore » Chemical Release Inventory report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. In 1999 EPA promulgated a final rule on Persistent Bioaccumulative Toxics (PBTs). This rule added several chemicals to the EPCRA Section 313 list of toxic chemicals and established lower reporting thresholds for these and other PBT chemicals that were already reportable under EPCRA Section 313. These lower thresholds became applicable in reporting year 2000. In 2001, EPA expanded the PBT rule to include a lower reporting threshold for lead and lead compounds. Facilities that manufacture, process, or otherwise use more than 100 lb of lead or lead compounds must submit a Form R.« less

Development and application of an innovative expert decision support system to manage sediments and to assess environmental risk in freshwater ecosystems.

PubMed

Dagnino, Alessandro; Bo, Tiziano; Copetta, Andrea; Fenoglio, Stefano; Oliveri, Caterina; Bencivenga, Mauro; Felli, Angelo; Viarengo, Aldo

2013-10-01

With the aim of supporting decision makers to manage contamination in freshwater environments, an innovative expert decision support system (EDSS) was developed. The EDSS was applied in a sediment quality assessment along the Bormida river (NW, Italy) which has been heavily contaminated by an upstream industrial site for more than a century. Sampling sites were classified by means of comparing chemical concentrations with effect-based target values (threshold and probable effect concentrations). The level of each contaminant and the combined toxic pressure were used to rank sites into three categories: (i) uncontaminated (8 sites), (ii) mildly contaminated (4) and (iii) heavily contaminated (19). In heavily contaminated sediments, an environmental risk index (EnvRI) was determined by means of integrating chemical data with ecotoxicological and ecological parameters (triad approach). In addition a sediment risk index (SedRI) was computed from combining chemical and ecotoxicological data. Eight sites exhibited EnvRI values ≥0.25, the safety threshold level (range of EnvRI values: 0.14-0.31) whereas SedRI exceeded the safety threshold level at 6 sites (range of SedRI values: 0.16-0.36). At sites classified as mildly contaminated, sublethal biomarkers were integrated with chemical data into a biological vulnerability index (BVI), which exceeded the safety threshold level at one site (BVI value: 0.28). Finally, potential human risk was assessed in selected stations (11 sites) by integrating genotoxicity biomarkers (GTI index falling in the range 0.00-0.53). General conclusions drawn from the EDSS data include: (i) in sites classified as heavily contaminated, only a few exhibited some significant, yet limited, effects on biodiversity; (ii) restrictions in re-using sediments from heavily contaminated sites found little support in ecotoxicological data; (iii) in the majority of the sites classified as mildly contaminated, tested organisms exhibited low response levels; (iv) preliminary results on genotoxicity biomarkers indicate possible negative consequences for humans if exposed to river sediments from target areas. © 2013.

Interpreting results of cluster surveys in emergency settings: is the LQAS test the best option?

PubMed

Bilukha, Oleg O; Blanton, Curtis

2008-12-09

Cluster surveys are commonly used in humanitarian emergencies to measure health and nutrition indicators. Deitchler et al. have proposed to use Lot Quality Assurance Sampling (LQAS) hypothesis testing in cluster surveys to classify the prevalence of global acute malnutrition as exceeding or not exceeding the pre-established thresholds. Field practitioners and decision-makers must clearly understand the meaning and implications of using this test in interpreting survey results to make programmatic decisions. We demonstrate that the LQAS test--as proposed by Deitchler et al.--is prone to producing false-positive results and thus is likely to suggest interventions in situations where interventions may not be needed. As an alternative, to provide more useful information for decision-making, we suggest reporting the probability of an indicator's exceeding the threshold as a direct measure of "risk". Such probability can be easily determined in field settings by using a simple spreadsheet calculator. The "risk" of exceeding the threshold can then be considered in the context of other aggravating and protective factors to make informed programmatic decisions.

Interpreting results of cluster surveys in emergency settings: is the LQAS test the best option?

PubMed Central

Bilukha, Oleg O; Blanton, Curtis

2008-01-01

Cluster surveys are commonly used in humanitarian emergencies to measure health and nutrition indicators. Deitchler et al. have proposed to use Lot Quality Assurance Sampling (LQAS) hypothesis testing in cluster surveys to classify the prevalence of global acute malnutrition as exceeding or not exceeding the pre-established thresholds. Field practitioners and decision-makers must clearly understand the meaning and implications of using this test in interpreting survey results to make programmatic decisions. We demonstrate that the LQAS test–as proposed by Deitchler et al. – is prone to producing false-positive results and thus is likely to suggest interventions in situations where interventions may not be needed. As an alternative, to provide more useful information for decision-making, we suggest reporting the probability of an indicator's exceeding the threshold as a direct measure of "risk". Such probability can be easily determined in field settings by using a simple spreadsheet calculator. The "risk" of exceeding the threshold can then be considered in the context of other aggravating and protective factors to make informed programmatic decisions. PMID:19068120

Estimating the exceedance probability of rain rate by logistic regression

NASA Technical Reports Server (NTRS)

Chiu, Long S.; Kedem, Benjamin

1990-01-01

Recent studies have shown that the fraction of an area with rain intensity above a fixed threshold is highly correlated with the area-averaged rain rate. To estimate the fractional rainy area, a logistic regression model, which estimates the conditional probability that rain rate over an area exceeds a fixed threshold given the values of related covariates, is developed. The problem of dependency in the data in the estimation procedure is bypassed by the method of partial likelihood. Analyses of simulated scanning multichannel microwave radiometer and observed electrically scanning microwave radiometer data during the Global Atlantic Tropical Experiment period show that the use of logistic regression in pixel classification is superior to multiple regression in predicting whether rain rate at each pixel exceeds a given threshold, even in the presence of noisy data. The potential of the logistic regression technique in satellite rain rate estimation is discussed.

Uranium hexafluoride public risk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, D.R.; Hui, T.E.; Yurconic, M.

1994-08-01

The limiting value for uranium toxicity in a human being should be based on the concentration of uranium (U) in the kidneys. The threshold for nephrotoxicity appears to lie very near 3 {mu}g U per gram kidney tissue. There does not appear to be strong scientific support for any other improved estimate, either higher or lower than this, of the threshold for uranium nephrotoxicity in a human being. The value 3 {mu}g U per gram kidney is the concentration that results from a single intake of about 30 mg soluble uranium by inhalation (assuming the metabolism of a standard person).more » The concentration of uranium continues to increase in the kidneys after long-term, continuous (or chronic) exposure. After chronic intakes of soluble uranium by workers at the rate of 10 mg U per week, the concentration of uranium in the kidneys approaches and may even exceed the nephrotoxic limit of 3 {mu}g U per gram kidney tissue. Precise values of the kidney concentration depend on the biokinetic model and model parameters assumed for such a calculation. Since it is possible for the concentration of uranium in the kidneys to exceed 3 {mu}g per gram tissue at an intake rate of 10 mg U per week over long periods of time, we believe that the kidneys are protected from injury when intakes of soluble uranium at the rate of 10 mg U per week do not continue for more than two consecutive weeks. For long-term, continuous occupational exposure to low-level, soluble uranium, we recommend a reduced weekly intake limit of 5 mg uranium to prevent nephrotoxicity in workers. Our analysis shows that the nephrotoxic limit of 3 {mu}g U per gram kidney tissues is not exceeded after long-term, continuous uranium intake at the intake rate of 5 mg soluble uranium per week.« less

Is the bitter rejection response always adaptive?

PubMed

Glendinning, J I

1994-12-01

The bitter rejection response consists of a suite of withdrawal reflexes and negative affective responses. It is generally assumed to have evolved as a way to facilitate avoidance of foods that are poisonous because they usually taste bitter to humans. Using previously published studies, the present paper examines the relationship between bitterness and toxicity in mammals, and then assesses the ecological costs and benefits of the bitter rejection response in carnivorous, omnivorous, and herbivorous (grazing and browsing) mammals. If the bitter rejection response accurately predicts the potential toxicity of foods, then one would expect the threshold for the response to be lower for highly toxic compounds than for nontoxic compounds. The data revealed no such relationship. Bitter taste thresholds varied independently of toxicity thresholds, indicating that the bitter rejection response is just as likely to be elicited by a harmless bitter food as it is by a harmful one. Thus, it is not necessarily in an animal's best interest to have an extremely high or low bitter threshold. Based on this observation, it was hypothesized that the adaptiveness of the bitter rejection response depends upon the relative occurrence of bitter and potentially toxic compounds in an animal's diet. Animals with a relatively high occurrence of bitter and potentially toxic compounds in their diet (e.g., browsing herbivores) were predicted to have evolved a high bitter taste threshold and tolerance to dietary poisons. Such an adaptation would be necessary because a browser cannot "afford" to reject all foods that are bitter and potentially toxic without unduly restricting its dietary options. At the other extreme, animals that rarely encounter bitter and potentially toxic compounds in their diet (e.g., carnivores) were predicted to have evolved a low bitter threshold. Carnivores could "afford" to utilize such a stringent rejection mechanism because foods containing bitter and potentially toxic compounds constitute a small portion of their diet. Since the low bitter threshold would reduce substantially the risk of ingesting anything poisonous, carnivores were also expected to have a relatively low tolerance to dietary poisons. This hypothesis was supported by a comparison involving 30 mammal species, in which a suggestive relationship was found between quinine hydrochloride sensitivity and trophic group, with carnivores > omnivores > grazers > browsers. Further support for the hypothesis was provided by a comparison across browsers and grazers in terms of the production of tannin-binding salivary proteins, which probably represent an adaptation for reducing the bitterness and astringency of tannins.(ABSTRACT TRUNCATED AT 400 WORDS)

40 CFR 435.15 - Standards of performance for new sources (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... toxicity ratio 6 shall not exceed 1.0. Biodegradation rate Biodegradation rate ratio 7 shall not exceed 1.0...) and (uu). 7 Biodegradation rate ratio = Cumulative headspace gas production (ml) of C16-C18 internal... fluids that meet the base fluid sediment toxicity ratio (Footnote 6), biodegradation rate ratio (Footnote...

40 CFR 435.15 - Standards of performance for new sources (NSPS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... toxicity ratio 6 shall not exceed 1.0. Biodegradation rate Biodegradation rate ratio 7 shall not exceed 1.0...) and (uu). 7 Biodegradation rate ratio = Cumulative headspace gas production (ml) of C16-C18 internal... fluids that meet the base fluid sediment toxicity ratio (Footnote 6), biodegradation rate ratio (Footnote...

40 CFR 435.15 - Standards of performance for new sources (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... toxicity ratio 6 shall not exceed 1.0. Biodegradation rate Biodegradation rate ratio 7 shall not exceed 1.0...) and (uu). 7 Biodegradation rate ratio = Cumulative headspace gas production (ml) of C16-C18 internal... fluids that meet the base fluid sediment toxicity ratio (Footnote 6), biodegradation rate ratio (Footnote...

RELATIONSHIPS AMONG EXCEEDENCES OF CHEMICAL CRITERIA OR GUIDELINES, THE RESULTS OF AMBIENT TOXICITY TESTS AND COMMUNITY METRICS IN AQUATIC ECOSYSTEMS (FINAL)

EPA Science Inventory

The EPA document, Relationships Among Exceedances of Chemical Criteria or Guidelines, the Results of Ambient Toxicity Tests, and Community Metrics in Aquatic Ecosystems, presents two studies where the three general approaches for the ecological assessment of contaminant ex...

Mobilisation of toxic trace elements under various beach nourishments.

PubMed

Pit, Iris R; Dekker, Stefan C; Kanters, Tobias J; Wassen, Martin J; Griffioen, Jasper

2017-12-01

To enhance protection and maintain wide beaches for recreation, beaches are replenished with sand: so-called beach nourishments. We compared four sites: two traditional beach nourishments, a mega beach nourishment and a reference without beach nourishment. Two sites contain calcareous-rich sand, whereas the other two sites have calcareous-poor sand. We aimed to understand hydrogeochemical processes to indicate factors critical for the mobility of trace elements at nourishments. We therefore analysed the chemical characteristics of sediment and pore water to ascertain the main drivers that mobilise toxic trace elements. With Dutch Quality Standards for soil and groundwater, the characteristics of sediment and pore water were compared to Target Values (the values at which there is a sustainable soil quality) and Intervention Values (the threshold above which the soil's functions are at risk). The pore water characteristics revealed that Target Values were regularly exceeded, especially for the nourishment sites and mainly for Mo (78%), Ni (24%), Cr (55%), and As (21%); Intervention Values for shallow groundwater were occasionally exceeded for As (2%), Cr (2%) and Zn (2%). The sediment characteristics did not exceed the Target Values and showed that trace elements were mainly present in the fine fraction of <150 μm. The oxidation of sulphide minerals such as pyrite resulted into the elevated concentration for all nourishment sites, especially when an unsaturated zone was present and influence of rainwater was apparent. To prevent trace metal mobility at a mega beach nourishment it is important to retain seawater influences and limit oxidation processes. In this respect, a shoreface nourishment is recommended rather than a mega beach nourishment with a thick unsaturated zone. Consequently, we conclude that whether a site is carbonate-rich or carbonate-poor is unimportant, as the influence of seawater will prevent decalcification, creating a low risk of mobilisation of trace elements. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Population exposure to trace elements in the Kilembe copper mine area, Western Uganda: A pilot study.

PubMed

Mwesigye, Abraham R; Young, Scott D; Bailey, Elizabeth H; Tumwebaze, Susan B

2016-12-15

The mining and processing of copper in Kilembe, Western Uganda, from 1956 to 1982 left over 15 Mt. of tailings containing cupriferous and cobaltiferous pyrite dumped within a mountain river valley. This pilot study was conducted to assess the nature and extent of risk to local populations from metal contamination arising from those mining activities. We determined trace element concentrations in mine tailings, soils, locally cultivated foods, house dust, drinking water and human biomarkers (toenails) using ICP-MS analysis of acid digested samples. The results showed that tailings, containing higher concentrations of Co, Cu, Ni and As compared with world average crust values had eroded and contaminated local soils. Pollution load indices revealed that 51% of agricultural soils sampled were contaminated with trace elements. Local water supplies were contaminated, with Co concentrations that exceeded Wisconsin (US) thresholds in 25% of domestic water supplies and 40% of Nyamwamba river water samples. Zinc exceeded WHO/FAO thresholds of 99.4mgkg -1 in 36% of Amaranthus vegetable samples, Cu exceeded EC thresholds of 20mgkg -1 in 19% of Amaranthus while Pb exceeded WHO thresholds of 0.3mgkg -1 in 47% of Amaranthus vegetables. In bananas, 20% of samples contained Pb concentrations that exceeded the WHO/FAO recommended threshold of 0.3mgkg -1 . However, risk assessment of local foods and water, based on hazard quotients (HQ values) revealed no potential health effects. The high external contamination of volunteers' toenails with some elements (even after a washing process) calls into question their use as a biomarker for metal exposure in human populations where feet are frequently exposed to soil dust. Any mitigation of Kilembe mine impacts should be aimed at remediation of agricultural soils, regulating the discharge of underground contaminated water but also containment of tailing erosion. Copyright © 2016 Elsevier B.V. All rights reserved.

A spatial approach to environmental risk assessment of PAH contamination.

PubMed

Bengtsson, Göran; Törneman, Niklas

2009-01-01

The extent of remediation of contaminated industrial sites depends on spatial heterogeneity of contaminant concentration and spatially explicit risk characterization. We used sequential Gaussian simulation (SGS) and indicator kriging (IK) to describe the spatial distribution of polycyclic aromatic hydrocarbons (PAHs), pH, electric conductivity, particle aggregate distribution, water holding capacity, and total organic carbon, and quantitative relations among them, in a creosote polluted soil in southern Sweden. The geostatistical analyses were combined with risk analyses, in which the total toxic equivalent concentration of the PAH mixture was calculated from the soil concentrations of individual PAHs and compared with ecotoxicological effect concentrations and regulatory threshold values in block sizes of 1.8 x 1.8 m. Most PAHs were spatially autocorrelated and appeared in several hot spots. The risk calculated by SGS was more confined to specific hot spot areas than the risk calculated by IK, and 40-50% of the site had PAH concentrations exceeding the threshold values with a probability of 80% and higher. The toxic equivalent concentration of the PAH mixture was dependent on the spatial distribution of organic carbon, showing the importance of assessing risk by a combination of measurements of PAH and organic carbon concentrations. Essentially, the same risk distribution pattern was maintained when Monte Carlo simulations were used for implementation of risk in larger (5 x 5 m), economically more feasible remediation blocks, but a smaller area became of great concern for remediation when the simulations included PAH partitioning to two separate sources, creosote and natural, of organic matter, rather than one general.

Method, memory media and apparatus for detection of grid disconnect

DOEpatents

Ye, Zhihong [Clifton Park, NY; Du, Pengwei [Troy, NY

2008-09-23

A phase shift procedure for detecting a disconnect of a power grid from a feeder that is connected to a load and a distributed generator. The phase shift procedure compares a current phase shift of the output voltage of the distributed generator with a predetermined threshold and if greater, a command is issued for a disconnect of the distributed generator from the feeder. To extend the range of detection, the phase shift procedure is used when a power mismatch between the distributed generator and the load exceeds a threshold and either or both of an under/over frequency procedure and an under/over voltage procedure is used when any power mismatch does not exceed the threshold.

Factors related to the joint probability of flooding on paired streams

USGS Publications Warehouse

Koltun, G.F.; Sherwood, J.M.

1998-01-01

The factors related to the joint probabilty of flooding on paired streams were investigated and quantified to provide information to aid in the design of hydraulic structures where the joint probabilty of flooding is an element of the design criteria. Stream pairs were considered to have flooded jointly at the design-year flood threshold (corresponding to the 2-, 10-, 25-, or 50-year instantaneous peak streamflow) if peak streamflows at both streams in the pair were observed or predicted to have equaled or exceeded the threshold on a given calendar day. Daily mean streamflow data were used as a substitute for instantaneous peak streamflow data to determine which flood thresholds were equaled or exceeded on any given day. Instantaneous peak streamflow data, when available, were used preferentially to assess flood-threshold exceedance. Daily mean streamflow data for each stream were paired with concurrent daily mean streamflow data at the other streams. Observed probabilities of joint flooding, determined for the 2-, 10-, 25-, and 50-year flood thresholds, were computed as the ratios of the total number of days when streamflows at both streams concurrently equaled or exceeded their flood thresholds (events) to the total number of days where streamflows at either stream equaled or exceeded its flood threshold (trials). A combination of correlation analyses, graphical analyses, and logistic-regression analyses were used to identify and quantify factors associated with the observed probabilities of joint flooding (event-trial ratios). The analyses indicated that the distance between drainage area centroids, the ratio of the smaller to larger drainage area, the mean drainage area, and the centroid angle adjusted 30 degrees were the basin characteristics most closely associated with the joint probabilty of flooding on paired streams in Ohio. In general, the analyses indicated that the joint probabilty of flooding decreases with an increase in centroid distance and increases with increases in drainage area ratio, mean drainage area, and centroid angle adjusted 30 degrees. Logistic-regression equations were developed, which can be used to estimate the probability that streamflows at two streams jointly equal or exceed the 2-year flood threshold given that the streamflow at one of the two streams equals or exceeds the 2-year flood threshold. The logistic-regression equations are applicable to stream pairs in Ohio (and border areas of adjacent states) that are unregulated, free of significant urban influences, and have characteristics similar to those of the 304 gaged stream pairs used in the logistic-regression analyses. Contingency tables were constructed and analyzed to provide information about the bivariate distribution of floods on paired streams. The contingency tables showed that the percentage of trials in which both streams in the pair concurrently flood at identical recurrence-interval ranges generally increased as centroid distances decreased and was greatest for stream pairs with adjusted centroid angles greater than or equal to 60 degrees and drainage area ratios greater than or equal to 0.01. Also, as centroid distance increased, streamflow at one stream in the pair was more likely to be in a less than 2-year recurrence-interval range when streamflow at the second stream was in a 2-year or greater recurrence-interval range.

Histotripsy Lesion Formation Using an Ultrasound Imaging Probe Enabled by a Low-Frequency Pump Transducer.

PubMed

Lin, Kuang-Wei; Hall, Timothy L; Xu, Zhen; Cain, Charles A

2015-08-01

When histotripsy pulses shorter than 2 cycles are applied, the formation of a dense bubble cloud relies only on the applied peak negative pressure (p-) exceeding the "intrinsic threshold" of the medium (absolute value of 26-30 MPa in most soft tissues). It has been found that a sub-threshold high-frequency probe pulse (3 MHz) can be enabled by a sub-threshold low-frequency pump pulse (500 kHz) where the sum exceeds the intrinsic threshold, thus generating lesion-producing dense bubble clouds ("dual-beam histotripsy"). Here, the feasibility of using an imaging transducer to provide the high-frequency probe pulse in the dual-beam histotripsy approach is investigated. More specifically, an ATL L7-4 imaging transducer (Philips Healthcare, Andover, MA, USA), pulsed by a V-1 Data Acquisition System (Verasonics, Redmond, WA, USA), was used to generate the high-frequency probe pulses. The low-frequency pump pulses were generated by a 20-element 345-kHz array transducer, driven by a custom high-voltage pulser. These dual-beam histotripsy pulses were applied to red blood cell tissue-mimicking phantoms at a pulse repetition frequency of 1 Hz, and optical imaging was used to visualize bubble clouds and lesions generated in the red blood cell phantoms. The results indicated that dense bubble clouds (and resulting lesions) were generated when the p- of the sub-threshold pump and probe pulses combined constructively to exceed the intrinsic threshold. The average size of the smallest reproducible lesions using the imaging probe pulse enabled by the sub-threshold pump pulse was 0.7 × 1.7 mm, whereas that using the supra-threshold pump pulse alone was 1.4 × 3.7 mm. When the imaging transducer was steered laterally, bubble clouds and lesions were steered correspondingly until the combined p- no longer exceeded the intrinsic threshold. These results were also validated with ex vivo porcine liver experiments. Using an imaging transducer for dual-beam histotripsy can have two advantages: (i) lesion steering can be achieved using the steering of the imaging transducer (implemented with the beamformer of the accompanying programmable ultrasound system), and (ii) treatment can be simultaneously monitored when the imaging transducer is used in conjunction with an ultrasound imaging system. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Data on Streamflow and Quality of Water and Bottom Sediment in and near Humboldt Wildlife Management Area, Churchill and Pershing Counties, Nevada, 1998-2000

USGS Publications Warehouse

Paul, Angela P.; Thodal, Carl E.

2003-01-01

This study was initiated to expand upon previous findings that indicated concentrations of dissolved solids, arsenic, boron, mercury, molybdenum, selenium, and uranium were either above geochemical background concentrations or were approaching or exceeding ecological criteria in the lower Humboldt River system. Data were collected from May 1998 to September 2000 to further characterize streamflow and surface-water and bottom-sediment quality in the lower Humboldt River, selected agricultural drains, Upper Humboldt Lake, and Lower Humboldt Drain (ephemeral outflow from Humboldt Sink). During this study, flow in the lower Humboldt River was either at or above average. Flows in Army and Toulon Drains generally were higher than reported in previous investigations. An unnamed agricultural drain contributed a small amount to the flow measured in Army Drain. In general, measured concentrations of sodium, chloride, dissolved solids, arsenic, boron, molybdenum, and uranium were higher in water from agricultural drains than in Humboldt River water during this study. Mercury concentrations in water samples collected during the study period typically were below the laboratory reporting level. However, low-level mercury analyses showed that samples collected in August 1999 from Army Drain had higher mercury concentrations than those collected from the river or Toulon Drain or the Lower Humboldt Drain. Ecological criteria and effect concentrations for sodium, chloride, dissolved solids, arsenic, boron, mercury, and molybdenum were exceeded in some water samples collected as part of this study. Although water samples from the agricultural drains typically contained higher concentrations of sodium, chloride, dissolved solids, arsenic, boron, and uranium, greater instantaneous loads of these constituents were carried in the river near Lovelock than in agricultural drains during periods of high flow or non-irrigation. During this study, the high flows in the lower Humboldt River produced the maximum instantaneous loads of sodium, chloride, dissolved solids, arsenic, boron, molybdenum, and uranium at all river-sampling sites, except molybdenum near Imlay. Nevada Division of Environmental Protection monitoring reports on mine-dewatering discharge for permitted releases of treated effluent to the surface waters of the Humboldt River and its tributaries were reviewed for reported discharges and trace-element concentrations from June 1998 to September 1999. These data were compared with similar information for the river near Imlay. In all bottom sediments collected for this study, arsenic concentrations exceeded the Canadian Freshwater Interim Sediment-Quality Guideline for the protection of aquatic life and probable-effect level (concentration). Sediments collected near Imlay, Rye Patch Reservoir, Lovelock, and from Toulon Drain and Army Drain were found to contain cadmium and chromium concentrations that exceeded Canadian criteria. Chromium concentrations in sediments collected from these sites also exceeded the consensus-based threshold-effect concentration. The Canadian criterion for sediment copper concentration was exceeded in sediments collected from the Humboldt River near Lovelock and from Toulon, Army, and the unnamed agricultural drains. Mercury in sediments collected near Imlay and from Toulon Drain in August 1999 exceeded the U.S. Department of the Interior sediment probable-effect level. Nickel concentrations in sediments collected during this study were above the consensus-based threshold-effect concentration. All other river and drain sediments had constituent concentrations below protective criteria and toxicity thresholds. In Upper Humboldt Lake, chloride, dissolved solids, arsenic, boron, molybdenum, and uranium concentrations in surface-water samples collected near the mouth of the Humboldt River generally were higher than in samples collected near the mouth of Army Drain. Ecological criteria or effect con

Effects on aquatic and human health due to large scale bioenergy crop expansion.

PubMed

Love, Bradley J; Einheuser, Matthew D; Nejadhashemi, A Pouyan

2011-08-01

In this study, the environmental impacts of large scale bioenergy crops were evaluated using the Soil and Water Assessment Tool (SWAT). Daily pesticide concentration data for a study area consisting of four large watersheds located in Michigan (totaling 53,358 km²) was estimated over a six year period (2000-2005). Model outputs for atrazine, bromoxynil, glyphosate, metolachlor, pendimethalin, sethoxydim, triflualin, and 2,4-D model output were used to predict the possible long-term implications that large-scale bioenergy crop expansion may have on the bluegill (Lepomis macrochirus) and humans. Threshold toxicity levels were obtained for the bluegill and for human consumption for all pesticides being evaluated through an extensive literature review. Model output was compared to each toxicity level for the suggested exposure time (96-hour for bluegill and 24-hour for humans). The results suggest that traditional intensive row crops such as canola, corn and sorghum may negatively impact aquatic life, and in most cases affect the safe drinking water availability. The continuous corn rotation, the most representative rotation for current agricultural practices for a starch-based ethanol economy, delivers the highest concentrations of glyphosate to the stream. In addition, continuous canola contributed to a concentration of 1.11 ppm of trifluralin, a highly toxic herbicide, which is 8.7 times the 96-hour ecotoxicity of bluegills and 21 times the safe drinking water level. Also during the period of study, continuous corn resulted in the impairment of 541,152 km of stream. However, there is promise with second-generation lignocellulosic bioenergy crops such as switchgrass, which resulted in a 171,667 km reduction in total stream length that exceeds the human threshold criteria, as compared to the base scenario. Results of this study may be useful in determining the suitability of bioenergy crop rotations and aid in decision making regarding the adaptation of large-scale bioenergy cropping systems. Published by Elsevier B.V.

Smartphone threshold audiometry in underserved primary health-care contexts.

PubMed

Sandström, Josefin; Swanepoel, De Wet; Carel Myburgh, Hermanus; Laurent, Claude

2016-01-01

To validate a calibrated smartphone-based hearing test in a sound booth environment and in primary health-care clinics. A repeated-measure within-subject study design was employed whereby air-conduction hearing thresholds determined by smartphone-based audiometry was compared to conventional audiometry in a sound booth and a primary health-care clinic environment. A total of 94 subjects (mean age 41 years ± 17.6 SD and range 18-88; 64% female) were assessed of whom 64 were tested in the sound booth and 30 within primary health-care clinics without a booth. In the sound booth 63.4% of conventional and smartphone thresholds indicated normal hearing (≤15 dBHL). Conventional thresholds exceeding 15 dB HL corresponded to smartphone thresholds within ≤10 dB in 80.6% of cases with an average threshold difference of -1.6 dB ± 9.9 SD. In primary health-care clinics 13.7% of conventional and smartphone thresholds indicated normal hearing (≤15 dBHL). Conventional thresholds exceeding 15 dBHL corresponded to smartphone thresholds within ≤10 dB in 92.9% of cases with an average threshold difference of -1.0 dB ± 7.1 SD. Accurate air-conduction audiometry can be conducted in a sound booth and without a sound booth in an underserved community health-care clinic using a smartphone.

Rainfall thresholds for forecasting landslides in the Seattle, Washington, area - exceedance and probability

USGS Publications Warehouse

Chleborad, Alan F.; Baum, Rex L.; Godt, Jonathan W.

2006-01-01

Empirical rainfall thresholds and related information form a basis for forecasting landslides in the Seattle area. A formula for a cumulative rainfall threshold (CT), P3=3.5-0.67P15, defined by rainfall amounts (in inches) during the last 3 days (72 hours), P3, and the previous 15 days (360 hours), P15, was developed from analysis of historical data for 91 landslides that occurred as part of 3-day events of three or more landslides between 1933 and 1997. Comparison with historical records for 577 landslides (including some used in developing the CT) indicates that the CT captures more than 90 percent of historical landslide events of three or more landslides in 1-day and 3-day periods that were recorded from 1978 to 2003. However, the probability of landslide occurrence on a day when the CT is exceeded at any single rain gage (8.4 percent) is low, and additional criteria are needed to confidently forecast landslide occurrence. Exceedance of a rainfall intensity-duration threshold I=3.257D-1.13, for intensity, I, (inch per hour) and duration, D, (hours), corresponds to a higher probability of landslide occurrence (42 percent at any 3 rain gages or 65 percent at any 10 rain gages), but it predicts fewer landslides. Both thresholds must be used in tandem to forecast landslide occurrence in Seattle.

Species-dependence of cyanobacteria removal efficiency by different drinking water treatment processes.

PubMed

Zamyadi, Arash; Dorner, Sarah; Sauvé, Sébastien; Ellis, Donald; Bolduc, Anouka; Bastien, Christian; Prévost, Michèle

2013-05-15

Accumulation and breakthrough of several potentially toxic cyanobacterial species within drinking water treatment plants (DWTP) have been reported recently. The objectives of this project were to test the efficiency of different treatment barriers in cyanobacterial removal. Upon observation of cyanobacterial blooms, intensive sampling was conducted inside a full scale DWTP at raw water, clarification, filtration and oxidation processes. Samples were taken for microscopic speciation/enumeration and microcystins analysis. Total cyanobacteria cell numbers exceeded World Health Organisation and local alert levels in raw water (6,90,000 cells/mL). Extensive accumulation of cyanobacteria species in sludge beds and filters, and interruption of treatment were observed. Aphanizomenon cells were poorly coagulated and they were not trapped efficiently in the sludge. It was also demonstrated that Aphanizomenon cells passed through and were not retained over the filter. However, Microcystis, Anabaena, and Pseudanabaena cells were adequately removed by clarification and filtration processes. The breakthrough of non toxic cyanobacterial cells into DWTPs could also result in severe treatment disruption leading to plant shutdown. Application of intervention threshold values restricted to raw water does not take into consideration the major long term accumulation of potentially toxic cells in the sludge and the risk of toxins release. Thus, a sampling regime inside the plant adapted to cyanobacterial occurrence and intensity is recommended. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mycological and ecotoxicological characterisation of landfill leachate before and after traditional treatments.

PubMed

Tigini, Valeria; Prigione, Valeria; Varese, Giovanna Cristina

2014-07-15

Pollution caused by landfill leachates is one of the main problems of urbanised areas, on account of their chemical composition, which turn in an ineffective treatment. A characterisation of leachates, which takes into account chemical, ecotoxicological and mycological aspects, is basilar for the evaluation of environmental impact of leachate and the development of suitable treatment techniques. In this study, the toxicity of a raw leachate and an effluent coming from traditional wastewater treatment plant was assessed by means of 4 ecotoxicological assays. Both the samples exceed the legal threshold value according to all the tested organisms, indicating the ineffectiveness of activated sludge treatment in the reduction of toxicity. The autochthonous mycoflora of the two samples was evaluated by filtration. The fungal load was 73 CFU for leachate and 102 CFU for the effluent. Ascomycetes were the dominant fraction (81% and 61%, for leachate and effluent respectively), followed by basidiomycetes (19% and 39%, respectively). Most of them were potential emerging pathogens. A decolourisation screening with autochthonous fungi was set up towards both samples in the presence or absence of glucose. Eleven fungi (basidiomycetes and ascomycetes) achieved up to 38% decolourisation yields, showing to be promising fungi for the bioremediation of leachates. Further experiment will be aimed to the study of decolourisation mechanism and toxicity reduction. Copyright © 2014 Elsevier B.V. All rights reserved.

2004 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Stockton

2006-01-15

Section 313 of Emergency Planning and Community Right-to-Know Act (EPCRA) specifically requires facilities to submit a Toxic Chemical Release Inventory Report (Form R) to the U.S. Environmental Protection Agency (EPA) and state agencies if the owners and operators manufacture, process, or otherwise use any of the listed toxic chemicals above listed threshold quantities. EPA compiles this data in the Toxic Release Inventory database. Form R reports for each chemical over threshold quantities must be submitted on or before July 1 each year and must cover activities that occurred at the facility during the previous year. For reporting year 2004, Losmore » Alamos National Laboratory (LANL or the Laboratory) submitted Form R reports for lead compounds, nitric acid, and nitrate compounds as required under the EPCRA Section 313. No other EPCRA Section 313 chemicals were used in 2004 above the reportable thresholds. This document provides a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2004, as well as background information about data included on the Form R reports.« less

40 CFR 372.27 - Alternate threshold and certification.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 29 2013-07-01 2013-07-01 false Alternate threshold and certification...-TO-KNOW Reporting Requirements § 372.27 Alternate threshold and certification. (a) Except as provided... toxic chemical, the owner or operator of a facility may apply an alternate threshold of 1 million pounds...

Contact toxicity of twenty insecticides applied to Symmerista canicosta

Treesearch

Jacqueline L. Robertson; Robert L. Lyon; Fay L. Shon; Nancy L. Gillette

1972-01-01

Twenty insecticides were tested by topical application on mixed groups of 4th- and 5th -stage larvae of Symmerista canicosta Franclemont. Four exceeded DDT in toxicity at LD50 but only resmethrin was significantly mor toxic. Most of the compounds showed unusually high toxicities. Twelve, listed in decreasing order of toxicity...

Metal contamination in environmental media in residential areas around Romanian mining sites.

PubMed

Neamtiu, Iulia A; Al-Abed, Souhail R; McKernan, John L; Baciu, Calin L; Gurzau, Eugen S; Pogacean, Anca O; Bessler, Scott M

2017-03-01

Hard-rock mining for metals, such as gold, silver, copper, zinc, iron and others, is recognized to have a significant impact on the environmental media, soil and water, in particular. Toxic contaminants released from mine waste to surface water and groundwater is the primary concern, but human exposure to soil contaminants either directly, via inhalation of airborne dust particles, or indirectly, via food chain (ingestion of animal products and/or vegetables grown in contaminated areas), is also, significant. In this research, we analyzed data collected in 2007, as part of a larger environmental study performed in the Rosia Montana area in Transylvania, to provide the Romanian governmental authorities with data on the levels of metal contamination in environmental media from this historical mining area. The data were also considered in policy decision to address mining-related environmental concerns in the area. We examined soil and water data collected from residential areas near the mining sites to determine relationships among metals analyzed in these different environmental media, using the correlation procedure in the SAS statistical software. Results for residential soil and water analysis indicate that the average values for arsenic (As) (85 mg/kg), cadmium (Cd) (3.2 mg/kg), mercury (Hg) (2.3 mg/kg) and lead (Pb) (92 mg/kg) exceeded the Romanian regulatory exposure levels [the intervention thresholds for residential soil in case of As (25 mg/kg) and Hg (2 mg/kg), and the alert thresholds in case of Pb (50 mg/kg) and Cd (3 mg/kg)]. Average metal concentrations in drinking water did not exceed the maximum contaminant level (MCL) imposed by the Romanian legislation, but high metal concentrations were found in surface water from Rosia creek, downstream from the former mining area.

Use of soil-streamwater relationships to assess regional patterns of acidic deposition effects in the northeastern USA

USGS Publications Warehouse

Siemion, Jason; Lawrence, Gregory B.; Murdoch, Peter S.

2013-01-01

Declines of acidic deposition levels by as much as 50% since 1990 have led to partial recovery of surface waters in the northeastern USA but continued depletion of soil calcium through this same period suggests a disconnection between soil and surface water chemistry. To investigate the role of soil-surface water interactions in recovery from acidification, the first regional survey to directly relate soil chemistry to stream chemistry during high flow was implemented in a 4144-km2 area of the Catskill region of New York, where acidic deposition levels are among the highest in the East.More than 40% of 95 streams sampled in the southern Catskill Mountains were determined to be acidified and had inorganic monomeric aluminum concentrations that exceeded a threshold that is toxic to aquatic biota. More than 80% likely exceeded this threshold during the highest flows, but less than 10% of more than 100 streams sampled were acidified in the northwestern portion of the region. Median Oa horizon soil base saturation ranged from 50% to 80% at 200 sites across the region, but median base saturation in the upper 10 cm of the B horizon was less than 20% across the region and was only 2% in the southern area. Aluminum is likely to be interfering with root uptake of calcium in the mineral horizon in approximately half the sampled watersheds. Stream chemistry was highly variable over the Catskill region and, therefore, did not always reflect the calcium depletion of the B horizon that our sampling suggested was nearly ubiquitous throughout the region. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Evidence of transboundary mercury and other pollutants in the Puyango-Tumbes River basin, Ecuador-Peru.

PubMed

Marshall, Bruce G; Veiga, Marcello M; Kaplan, Robert J; Adler Miserendino, Rebecca; Schudel, Gary; Bergquist, Bridget A; Guimarães, Jean R D; Sobral, Luis G S; Gonzalez-Mueller, Carolina

2018-04-25

In Portovelo in southern Ecuador, 87 gold processing centers along the Puyango-Tumbes River produce an estimated 6 tonnes of gold per annum using a combination of mercury amalgamation and/or cyanidation and processing poly-metallic ores. We analysed total Hg, Hg isotopes, total arsenic, cadmium, copper, lead and zinc in water and sediment along the Puyango in 2012-2014. The highest total mercury (THg) concentrations in sediments were found within a 40 km stretch downriver from the processing plants, with levels varying between 0.78-30.8 mg kg-1 during the dry season and 1.80-70.7 mg kg-1 during the wet season, with most concentrations above the CCME (Canadian Council of Ministers of the Environment) Probable Effect Level (PEL) of 0.5 mg kg-1. Data from mercury isotopic analyses support the conclusion that mercury use during gold processing in Portovelo is the source of Hg pollution found downstream in the Tumbes Delta in Peru, 160 km away. The majority of the water and sediment samples collected from the Puyango-Tumbes River had elevated concentrations of, arsenic, cadmium, copper, lead and zinc exceeding the CCME thresholds for the Protection of Aquatic Life. At monitoring points immediately below the processing plants, total dissolved concentrations of these metals exceeded the thresholds by 156-3567 times in surface waters and by 19-740 times in sediment. The results illustrate a significant transboundary pollution problem involving Hg and other toxic metals, amplified by the fact that the Puyango-Tumbes River is the only available water source in the semi-arid region of northern Peru.

Quinolizidine Alkaloid Biosynthesis in Lupins and Prospects for Grain Quality Improvement

PubMed Central

Frick, Karen M.; Kamphuis, Lars G.; Siddique, Kadambot H. M.; Singh, Karam B.; Foley, Rhonda C.

2017-01-01

Quinolizidine alkaloids (QAs) are toxic secondary metabolites found within the genus Lupinus, some species of which are commercially important grain legume crops including Lupinus angustifolius (narrow-leafed lupin, NLL), L. luteus (yellow lupin), L. albus (white lupin), and L. mutabilis (pearl lupin), with NLL grain being the most largely produced of the four species in Australia and worldwide. While QAs offer the plants protection against insect pests, the accumulation of QAs in lupin grain complicates its use for food purposes as QA levels must remain below the industry threshold (0.02%), which is often exceeded. It is not well understood what factors cause grain QA levels to exceed this threshold. Much of the early work on QA biosynthesis began in the 1970–1980s, with many QA chemical structures well-characterized and lupin cell cultures and enzyme assays employed to identify some biosynthetic enzymes and pathway intermediates. More recently, two genes associated with these enzymes have been characterized, however, the QA biosynthetic pathway remains only partially elucidated. Here, we review the research accomplished thus far concerning QAs in lupin and consider some possibilities for further elucidation and manipulation of the QA pathway in lupin crops, drawing on examples from model alkaloid species. One breeding strategy for lupin is to produce plants with high QAs in vegetative tissues while low in the grain in order to confer insect resistance to plants while keeping grain QA levels within industry regulations. With the knowledge achieved on alkaloid biosynthesis in other plant species in recent years, and the recent development of genomic and transcriptomic resources for NLL, there is considerable scope to facilitate advances in our knowledge of QAs, leading to the production of improved lupin crops. PMID:28197163

Quinolizidine Alkaloid Biosynthesis in Lupins and Prospects for Grain Quality Improvement.

PubMed

Frick, Karen M; Kamphuis, Lars G; Siddique, Kadambot H M; Singh, Karam B; Foley, Rhonda C

2017-01-01

Quinolizidine alkaloids (QAs) are toxic secondary metabolites found within the genus Lupinus , some species of which are commercially important grain legume crops including Lupinus angustifolius (narrow-leafed lupin, NLL), L. luteus (yellow lupin), L. albus (white lupin), and L. mutabilis (pearl lupin), with NLL grain being the most largely produced of the four species in Australia and worldwide. While QAs offer the plants protection against insect pests, the accumulation of QAs in lupin grain complicates its use for food purposes as QA levels must remain below the industry threshold (0.02%), which is often exceeded. It is not well understood what factors cause grain QA levels to exceed this threshold. Much of the early work on QA biosynthesis began in the 1970-1980s, with many QA chemical structures well-characterized and lupin cell cultures and enzyme assays employed to identify some biosynthetic enzymes and pathway intermediates. More recently, two genes associated with these enzymes have been characterized, however, the QA biosynthetic pathway remains only partially elucidated. Here, we review the research accomplished thus far concerning QAs in lupin and consider some possibilities for further elucidation and manipulation of the QA pathway in lupin crops, drawing on examples from model alkaloid species. One breeding strategy for lupin is to produce plants with high QAs in vegetative tissues while low in the grain in order to confer insect resistance to plants while keeping grain QA levels within industry regulations. With the knowledge achieved on alkaloid biosynthesis in other plant species in recent years, and the recent development of genomic and transcriptomic resources for NLL, there is considerable scope to facilitate advances in our knowledge of QAs, leading to the production of improved lupin crops.

Mercury and selenium concentrations in biofilm, macroinvertebrates, and fish collected in the Yankee Fork of the Salmon River, Idaho, USA, and their potential effects on fish health.

PubMed

Rhea, Darren T; Farag, Aïda M; Harper, David D; McConnell, Elizabeth; Brumbaugh, William G

2013-01-01

The Yankee Fork is a large tributary of the Salmon River located in central Idaho, USA, with an extensive history of placer and dredge-mining activities. Concentrations of selenium (Se) and mercury (Hg) in various aquatic trophic levels were measured in the Yankee Fork during 2001 and 2002. Various measurements of fish health were also performed. Sites included four on the mainstem of the Yankee Fork and two off-channel sites in partially reclaimed dredge pools used as rearing habitat for cultured salmonid eggs and fry. Hg concentrations in whole mountain whitefish and shorthead sculpin ranged from 0.28 to 0.56 μg/g dry weight (dw), concentrations that are generally less than those reported to have significant impacts on fish. Biofilm and invertebrates ranged from 0.05 to 0.43 μg Hg/g dw. Se concentrations measured in biota samples from the Yankee Fork were greater than many representative samples collected in the Snake and Columbia watersheds and often exceeded literature-based toxic thresholds. Biofilm and invertebrates ranged from 0.58 to 4.66 μg Se/g dw. Whole fish ranged from 3.92 to 7.10 μg Se/g dw, and gonads ranged from 6.91 to 31.84 μg Se/g dw. Whole-body Se concentrations exceeded reported toxicological thresholds at three of four sites and concentrations in liver samples were mostly greater than concentrations shown to have negative impacts on fish health. Histological examinations performed during this study noted liver abnormalities, especially in shorthead sculpin, a bottom-dwelling species.

Characterization and metal availability of copper, lead, antimony and zinc contamination at four Canadian small arms firing ranges.

PubMed

Laporte-Saumure, Mathieu; Martel, Richard; Mercier, Guy

2011-01-01

Backstop soils of four small-arms firing ranges (SAFRs) of the Canadian Force Bases (CFBs) were characterized in terms of their total soil Cu, Pb, Sb and Zn concentrations, grain size distribution, mineralogy, chemical properties, vertical in-depth contamination distribution (for one CFB), and scanning electron microscope (SEM-EDS) characterization. Metal availability from the soils was evaluated with three leaching tests: the toxicity characteristics leaching procedure (TCLP), representing a landfill leachate; the synthetic precipitation leaching procedure (SPLP), representing field conditions; and the gastric juice simulation test (GJST), representing the leachate of the human stomach during the digestive process and, therefore, the potential metal transfer to humans in the case of soil ingestion. Metal analyses of soils and leaching test extracts were conducted with an Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) instrument. Total soil results showed maximal concentrations of 27,100 mg/kg for Pb, 7720 mg/kg for Cu, 1080 mg/kg for Zn, and 570 mg/kg for Sb. The SEM-EDS analysis showed significant amounts of lead carbonates, which resulted from the alteration of the initial metallic Pb particles. Metal availability evaluation with the leaching tests showed that TCLP Pb and Sb thresholds were exceeded. For the SPLP and the GJST, the drinking water thresholds of the Ministère du Développement Durable, de l'Environnement et des Pares (MDDEP) of Quebec were exceeded by Pb and Sb. The metal availability assessment showed that SAFR backstop soils may pose a potential risk to the environment, groundwater and humans, and affect the management of such soils in order to minimize potential metal dispersion in the environment.

Mercury and selenium concentrations in biofilm, macroinvertebrates, and fish collected in the Yankee Fork of the Salmon River, Idaho, USA, and their potential effects on fish health

USGS Publications Warehouse

Rhea, Darren T.; Farag, Aïda M.; Harper, David D.; McConnell, Elizabeth; Brumbaugh, William G.

2013-01-01

The Yankee Fork is a large tributary of the Salmon River located in central Idaho, USA, with an extensive history of placer and dredge-mining activities. Concentrations of selenium (Se) and mercury (Hg) in various aquatic trophic levels were measured in the Yankee Fork during 2001 and 2002. Various measurements of fish health were also performed. Sites included four on the mainstem of the Yankee Fork and two off-channel sites in partially reclaimed dredge pools used as rearing habitat for cultured salmonid eggs and fry. Hg concentrations in whole mountain whitefish and shorthead sculpin ranged from 0.28 to 0.56 μg/g dry weight (dw), concentrations that are generally less than those reported to have significant impacts on fish. Biofilm and invertebrates ranged from 0.05 to 0.43 μg Hg/g dw. Se concentrations measured in biota samples from the Yankee Fork were greater than many representative samples collected in the Snake and Columbia watersheds and often exceeded literature-based toxic thresholds. Biofilm and invertebrates ranged from 0.58 to 4.66 μg Se/g dw. Whole fish ranged from 3.92 to 7.10 μg Se/g dw, and gonads ranged from 6.91 to 31.84 μg Se/g dw. Whole-body Se concentrations exceeded reported toxicological thresholds at three of four sites and concentrations in liver samples were mostly greater than concentrations shown to have negative impacts on fish health. Histological examinations performed during this study noted liver abnormalities, especially in shorthead sculpin, a bottom-dwelling species.

Concentrations and patterns of perfluoroalkyl acids in Georgia, USA surface waters near and distant to a major use source.

PubMed

Konwick, Brad J; Tomy, Gregg T; Ismail, Nargis; Peterson, James T; Fauver, Rebecca J; Higginbotham, David; Fisk, Aaron T

2008-10-01

Perfluoroalkyl acids (PFAAs) are widespread contaminants emanating from, among other sources, the production/degradation of fluorinated chemicals used in surface repellant applications, such as carpet manufacturing. The goal of the present study was to assess the concentrations of PFAAs, including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUA), and perfluorooctane sulfonamide (PFOSA), in surface waters both near a wastewater land application system (LAS) in Dalton (GA, USA), home to North America's largest carpet manufacturing site, and distant to this location (Altamaha River, GA, USA) to understand the fate of PFAAs in freshwater. Levels of PFAAs were high in the Conasauga River (GA, USA) downstream of the LAS (PFOA, 253-1,150 ng/L; PFOS, 192-318 ng/L; PFNA, 202-369 ng/L; PFDA, 30.1-113 ng/L; PFUA, 58.0-99.2 ng/L; PFOSA, 162-283 ng/L) and in streams and ponds in Dalton (PFOA, 49.9-299 ng/L; PFOS, 15.8-120 ng/L), and were among the highest measured at a nonspill or direct-release location. Perfluoroalkyl acids in the Altamaha River were much lower (PFOA, 3.0-3.1 ng/L; PFOS, 2.6-2.7 ng/L), but were a source of PFAAs to Georgia's estuaries. A preliminary hazard assessment indicated that concentrations of PFOS at two sites in the Conasauga River exceeded the threshold effect predicted for birds consuming aquatic organisms that are exposed continuously to the PFOS levels at these sites. Assuming that toxicity for all PFAAs quantified is equal to that of PFOS, the sum total PFAAs at two sites within the Conasauga River exceeded PFOS thresholds for aquatic and avian species, warranting additional research.

48 CFR 8.405-1 - Ordering procedures for supplies, and services not requiring a statement of work.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Orders at or below the micro-purchase threshold. Ordering activities may place orders at, or below, the micro-purchase threshold with any Federal Supply Schedule contractor that can meet the agency's needs... attempt to distribute orders among contractors. (c) Orders exceeding the micro-purchase threshold but not...

A ten year summary of concurrent ambient water column and sediment toxicity tests in the Chesapeake Bay watershed: 1990-1999.

PubMed

Hall, Lenwood W; Anderson, Ronald D; Alden, Raymond W

2002-06-01

The goal of this study was to identify the relative toxicity of ambient areas in the Chesapeake Bay watershed by using a suite of concurrent water column and sediment toxicity tests at seventy-five ambient stations in 20 Chesapeake Bay rivers from 1990 through 1999. Spatial and temporal variability was examined at selected locations throughout the 10 yr study. Inorganic and organic contaminants were evaluated in ambient water and sediment concurrently with water column and sediment tests to assess possible causes of toxicity although absolute causality can not be established. Multivariate statistical analysis was used to develop a multiple endpoint toxicity index (TOX-INDEX) at each station for both water column and sediment toxicity data. Water column tests from the 10 yr testing period showed that 49% of the time, some degree of toxicity was reported. The most toxic sites based on water column results were located in urbanized areas such as the Anacostia River, Elizabeth River and the Middle River. Water quality criteria for copper, lead, mercury, nickel and zinc were exceeded at one or more of these sites. Water column toxicity was also reported in localized areas of the South and Chester Rivers. Both spatial and temporal variability was reported from the suite of water column toxicity tests. Some degree of sediment toxicity was reported from 62% of the tests conducted during the ten year period. The Elizabeth River and Baltimore Harbor stations were reported as the most toxic areas based on sediment results. Sediment toxicity guidelines were exceeded for one or more of the following metals at these two locations: arsenic, cadmium, chromium, copper, lead, nickel and zinc. At the Elizabeth River stations nine of sixteen semi-volatile organics and two of seven pesticides measured exceeded the ER-M values in 1990. Ambient sediment toxicity tests in the Elizabeth River in 1996 showed reduced toxicity. Various semi-volatile organics exceeded the ER-M values at a number of Baltimore Harbor sites; pyrene and dibenzo(a,h)anthracene were particularly high at one of the stations (Northwest Harbor). Localized sediment toxicity was also reported in the Chester, James, Magothy, Rappahannock, and Potomac Rivers but the link with contaminants was not determined. Both spatial and temporal variability was less for sediment toxicity data when compared with water column toxicity data. A comparison of water column and sediment toxicity data for the various stations over the 10 yr study showed that approximately half the time agreement occurred (either both suite of tests showed toxicity or neither suite of tests showed toxicity).

Relationship between surface and free tropospheric ozone in the Western U.S.

PubMed

Jaffe, Dan

2011-01-15

Ozone is an important air pollutant that affects lung function. In the U.S., the EPA has reduced the allowable O(3) concentrations several times over the last few decades. This puts greater emphasis on understanding the interannual variability and the contributions to surface O(3) from all sources. We have examined O(3) data from 11 rural CASTNET sites in the western US for the period 1995-2009. The 11 surface sites show a similar seasonal cycle and generally a good correlation in the deseasonalized monthly means, indicating that there are large scale influences on O(3) that operate across the entire western US. These sites also show a good correlation between site elevation and annual mean O(3), indicating a significant contribution from the free troposphere. We examined the number of exceedance days for each site, defined as a day when the Maximum Daily 8-h Average (MDA8) exceeds a threshold value. Over this time period, more than half of these sites exceeded an MDA8 threshold of 70 ppbv at least 4 times per year, and all sites exceeded a threshold value of 65 ppbv at least 4 times per year. The transition to lower threshold values increases substantially the number of exceedance days, especially during spring, reflecting the fact that background O(3) peaks during spring. We next examined the correlation between surface O(3) and free tropospheric O(3) in the same region, as measured by routine balloon launches from Boulder, CO. Using ozone measured by the balloon sensor in the range of 3-6 km above sea level we find statistically significant correlations between surface and free tropospheric O(3) in spring and summer months using both monthly means, daily MDA8 values, and the number of surface exceedance days. We suggest that during spring this correlation reflects variations in the flux of O(3) transport from the free troposphere to the surface. In summer, free tropospheric and surface concentrations of O(3) and the number of exceedance days are all significantly correlated with emissions from biomass burning in the western US. This indicates that wildfires significantly increase the number of exceedance days across the western U.S.

Electrical leakage detection circuit

DOEpatents

Wild, Arthur

2006-09-05

A method is provided for detecting electrical leakage between a power supply and a frame of a vehicle or machine. The disclosed method includes coupling a first capacitor between a frame and a first terminal of a power supply for a predetermined period of time. The current flowing between the frame and the first capacitor is limited to a predetermined current limit. It is determined whether the voltage across the first capacitor exceeds a threshold voltage. A first output signal is provided when the voltage across the capacitor exceeds the threshold voltage.

Histotripsy Lesion Formation using an Ultrasound Imaging Probe Enabled by a Low-Frequency Pump Transducer

PubMed Central

Lin, Kuang-Wei; Hall, Timothy L.; Xu, Zhen; Cain, Charles A.

2015-01-01

When applying histotripsy pulses shorter than 2 cycles, the formation of a dense bubble cloud only relies on the applied peak negative pressure (p-) exceeding the “intrinsic threshold” of the medium (absolute value of 26 – 30 MPa in most soft tissue). A previous study conducted by our research group showed that a sub-threshold high-frequency probe pulse (3 MHz) can be enabled by a sub-threshold low-frequency pump pulse (500 kHz) where the sum exceeds the intrinsic threshold, thus generating lesion-producing dense bubble clouds (“dual-beam histotripsy”). This paper investigates the feasibility of using an imaging transducer to provide the high-frequency probe pulse in the dual-beam histotripsy approach. More specifically, an ATL L7–4 imaging transducer, pulsed by a Verasonics V-1 Data Acquisition System, was used to generate the high-frequency probe pulses. The low-frequency pump pulses were generated by a 20-element 345 kHz array transducer, driven by a custom high voltage pulser. These dual-beam histotripsy pulses were applied to red-blood-cell (RBC) tissue-mimicking phantoms at a pulse repetition frequency of 1 Hz, and optical imaging was used to visualize bubble clouds and lesions generated in the RBC phantoms. The results showed that dense bubble clouds (and resulting lesions) were generated when the p- of the sub-threshold pump and probe pulses combined constructively to exceed the intrinsic threshold. The average size of the smallest reproducible lesions using the imaging probe pulse enabled by the sub-threshold pump pulse was 0.7 × 1.7 mm while that using the supra-threshold pump pulse alone was 1.4 × 3.7 mm. When the imaging transducer was steered laterally, bubble clouds and lesions were steered correspondingly until the combined p- no longer exceeded the intrinsic threshold. These results were also validated with ex vivo porcine liver experiments. Using an imaging transducer for dual-beam histotripsy can have two advantages, 1) lesion steering can be achieved using the steering of the imaging transducer (implemented with the beamformer of the accompanying programmable ultrasound system) and 2) treatment can be simultaneously monitored when the imaging transducer is used in conjunction with an ultrasound imaging system. PMID:25929995

Organochlorine accumulation by Sentinel Mallards at the Winston-Thomas sewage treatment plant, Bloomington, Indiana

USGS Publications Warehouse

Custer, T.W.; Sparks, D.W.; Sobiech, S.A.; Hines, R.K.; Melancon, M.J.

1996-01-01

Farm-raised l2-month-old female mallards (Anas platyrhynchos) were released at the Winston-Thomas sewage treatment plant, Bloomington, Indiana. Five mallards were sacrificed at the start of the study and at approximately 10-day intervals through day 100. Concentrations of polychlorinated biphenyls (PCBs) in carcasses increased linearly with time of exposure and exceeded 16 mcg/g wet weight by day 100; PCBs in breast muscle exceeded 3.9 mcg/g by day 100. These PCB values are among the highest recorded for wild or sentinel waterfowl. PCB concentrations in breast muscle (26-523 mcg/g lipid weight) were 50-1,000 times greater than human consumption guidelines for edible poultry in Canada (0.5 mcg/g lipid weight) and 9-176 times greater than consumption guidelines for edible poultry in the United States (3.0 mcg/g lipid weight). Additionally, PCB concentrations in carcass and breast muscle exceeded the threshold of the Great Lakes Sport Fish Consumption Advisory 'do not eat' category (1.9 mcg/g wet weight) by day 20 and day 50, respectively. Hepatic cytochrome P450-associated monooxygenases including BROD (benzyloxyresorufin-O-dealkylase), EROD (ethoxyresorufin-O-dealkylase), and PROD (pentoxyresorufin-O-dealkylase) were induced over 5-fold compared to reference mallards. BROD, EROD, and PROD were each significantly correlated to total PCBs and to the toxicity of selected PCB congeners, relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Organochlorine accumulation by sentinel mallards at the Winston-Thomas sewage treatment plant, Bloomington, Indiana

USGS Publications Warehouse

Custer, T.W.; Sparks, D.W.; Sobiech, S.A.; Hines, R.K.; Melancon, M.J.

1996-01-01

Farm-raised 12-month-old female mallards (Anas platyrhynchos) were released at the Winston-Thomas sewage treatment plant, Bloomington, Indiana. Five mallards were sacrificed at the start of the study and at approximately 10-day intervals through day 100. Concentrations of polychlorinated biphenyls (PCBs) in carcasses increased linearly with time of exposure and exceeded 16 g/g wet weight by day 100; PCBs in breast muscle exceeded 3.9 g/g by day 100. These PCB values are among the highest recorded for wild or sentinel waterfowl. PCB concentrations in breast muscle (26a??523 g/g lipid weight) were 50a??1,000 times greater than human consumption guidelines for edible poultry in Canada (0.5 g/g lipid weight) and 9a??176 times greater than consumption guidelines for edible poultry in the United States (3.0 g/g lipid weight). Additionally, PCB concentrations in carcass and breast muscle exceeded the threshold of the Great Lakes Sport Fish Consumption Advisory do not eat category (1.9 g/g wet weight) by day 20 and day 50, respectively. Hepatic cytochrome P450-associated monooxygenases including BROD (benzyloxyresorufin-O-dealkylase), EROD (ethoxyresorufin-O-dealkylase), and PROD (pentoxyresorufin-O-dealkylase) were induced over 5-fold compared to reference mallards. BROD, EROD, and PROD were each significantly correlated to total PCBs and to the toxicity of selected PCB congeners, relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Extractability, plant yield and toxicity thresholds for boron in compost

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brinton, W.F.; Evans, E.; Blewett, C.

Boron (B) is a trace element essential to crop growth in small soil concentrations (0.2-1.5ppm), yet may produce plant toxicity symptoms readily as the amount in the soil solution increases over 2ppm. Our study examined commercial compost made with coal fly-ash used to prepare growing media for cultivars of varying sensitivity (corn, beans, cucumber, peas). We examined total vs. extractable boron content and relate final visual symptoms of B-toxicity to yields and tissue concentrations. Visual toxicity effects included tip burn (corn), leaf mottling and necrosis (beans and peas) and leaf mottling and cupping (cucumbers). Fly ash added to compost increasedmore » hot-water soluble (HWS) B in proportion to rate and in dependence on pH, with 30% and 10% of total-B expressed as HWS-B at a media pH of 6 and 7.5, respectively. Biomass for bean and cucumber was significantly reduced by 45 to 55%, respectively, by addition of 33% fly-ash compost to growing media (28ppm total-B) while plant tissue-B increased by 6- to 4-fold, respectively. Economic yield depressions in compost media are evident for all crops and appeared at levels of HWS-B in compost media exceeding 5 ppm. The study underscores the need for careful management of exogenous factors that may be present in composts and suggests detailed understanding of media-pH and cultivar preferences may be required in preparation of growing media in order to reduce potential negative growth effects.« less

Baseline blood Pb levels of black-necked stilts on the upper Texas coast

USGS Publications Warehouse

Riecke, Thomas V.; Conway, Warren C.; Haukos, David A.; Moon, Jena A.; Comer, Christopher E.

2015-01-01

There are no known biological requirements for lead (Pb), and elevated Pb levels in birds can cause a variety of sub-lethal effects and mortality. Historic and current levels of Pb in mottled ducks (Anas fulvigula) suggest that environmental sources of Pb remain available on the upper Texas coast. Because of potential risks of Pb exposure among coexisting marsh birds, black-necked stilt (Himantopus mexicanus) blood Pb concentrations were measured during the breeding season. Almost 80 % (n = 120) of 152 sampled stilts exceeded the background threshold (>20 μg/dL) for Pb exposure. However, blood Pb concentrations did not vary by age or gender, and toxic or potentially lethal concentrations were rare (<5 %). Consistent, low-level blood Pb concentrations of black-necked stilts in this study suggest the presence of readily bioavailable sources of Pb, although potential impacts on local stilt populations remain unclear.

Application of sediment quality guidelines in the assessment and management of contaminated surficial sediments in Port Jackson (Sydney Harbour), Australia.

PubMed

Birch, Gavin F; Taylor, Stuart E

2002-06-01

Sediments in the Port Jackson estuary are polluted by a wide range of toxicants and concentrations are among the highest reported for any major harbor in the world. Sediment quality guidelines (SQGs), developed by the National Oceanographic and Atmospheric Administration (NOAA) in the United States are used to estimate possible adverse biological effects of sedimentary contaminants in Port Jackson to benthic animals. The NOAA guidelines indicate that Pb, Zn, DDD, and DDE are the most likely contaminants to cause adverse biological effects in Port Jackson. On an individual chemical basis, the detrimental effects due to these toxicants may occur over extensive areas of the harbor, i.e., about 40%, 30%, 15% and 50%, respectively. The NOAA SQGs can also be used to estimate the probability of sediment toxicity for contaminant mixtures by determining the number of contaminants exceeding an upper guideline value (effects range medium, or ERM), which predicts probable adverse biological effects. The exceedence approach is used in the current study to estimate the probability of sediment toxicity and to prioritize the harbour in terms of possible adverse effects on sediment-dwelling animals. Approximately 1% of the harbor is mantled with sediment containing more than ten contaminants exceeding their respective ERM concentrations and, based on NOAA data, these sediments have an 80% probability of being toxic. Sediment with six to ten contaminants exceeding their respective ERM guidelines extend over approximately 4% of the harbor and have a 57% probability of toxicity. These areas are located in the landward reaches of embayments in the upper and central harbor in proximity to the most industrialised and urbanized part of the catchment. Sediment in a further 17% of the harbor has between one and five exceedences and has a 32% probability of being toxic. The application of SQGs developed by NOAA has not been tested outside North America, and the validity of using them in Port Jackson has yet to be demonstrated. The screening approach adopted here is to use SQGs to identify contaminants of concern and to determine areas of environmental risk. The practical application and management implications of the results of this investigation are discussed.

38 CFR 4.16 - Total disability ratings for compensation based on unemployability of the individual.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the U.S. Department of Commerce, Bureau of the Census, as the poverty threshold for one person... income exceeds the poverty threshold. Consideration shall be given in all claims to the nature of the...

38 CFR 4.16 - Total disability ratings for compensation based on unemployability of the individual.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the U.S. Department of Commerce, Bureau of the Census, as the poverty threshold for one person... income exceeds the poverty threshold. Consideration shall be given in all claims to the nature of the...

38 CFR 4.16 - Total disability ratings for compensation based on unemployability of the individual.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the U.S. Department of Commerce, Bureau of the Census, as the poverty threshold for one person... income exceeds the poverty threshold. Consideration shall be given in all claims to the nature of the...

12 CFR 1500.5 - What aggregate thresholds apply to merchant banking investments?

Code of Federal Regulations, 2010 CFR

2010-01-01

... investments held by the financial holding company under this part exceeds: (1) 30 percent of the Tier 1... percent of the Tier 1 capital of the financial holding company (b) How do these thresholds apply to a...

Commerce Spectrum Management Advisory Committee (CSMAC) Working Group (WG) 3 Phase 2 Study Summary

DTIC Science & Technology

2013-05-29

threshold Kauai Niihau 52 HTS Power Contours 1 kW transmitter power with 20 dB attenuation, 1 km grid spacing LTE base station received power (dBW...137.4 dBW LTE threshold Kauai Niihau 53 HTS LTE System Threshold Exceedance, 1755-1780 MHz 1 kW transmitter power, 1 km grid spacing

Toxicology

NASA Technical Reports Server (NTRS)

Macewen, J. W.

1973-01-01

Oxygen toxicity is examined, including the effects of oxygen partial pressure variations on toxicity and oxygen effects on ozone and nitrogen dioxide toxicity. Toxicity of fuels and oxidizers, such as hydrazines, are reported. Carbon monoxide, spacecraft threshold limit values, emergency exposure limits, spacecraft contaminants, and water quality standards for space missions are briefly summarized.

Modeling Source Water Threshold Exceedances with Extreme Value Theory

NASA Astrophysics Data System (ADS)

Rajagopalan, B.; Samson, C.; Summers, R. S.

2016-12-01

Variability in surface water quality, influenced by seasonal and long-term climate changes, can impact drinking water quality and treatment. In particular, temperature and precipitation can impact surface water quality directly or through their influence on streamflow and dilution capacity. Furthermore, they also impact land surface factors, such as soil moisture and vegetation, which can in turn affect surface water quality, in particular, levels of organic matter in surface waters which are of concern. All of these will be exacerbated by anthropogenic climate change. While some source water quality parameters, particularly Total Organic Carbon (TOC) and bromide concentrations, are not directly regulated for drinking water, these parameters are precursors to the formation of disinfection byproducts (DBPs), which are regulated in drinking water distribution systems. These DBPs form when a disinfectant, added to the water to protect public health against microbial pathogens, most commonly chlorine, reacts with dissolved organic matter (DOM), measured as TOC or dissolved organic carbon (DOC), and inorganic precursor materials, such as bromide. Therefore, understanding and modeling the extremes of TOC and Bromide concentrations is of critical interest for drinking water utilities. In this study we develop nonstationary extreme value analysis models for threshold exceedances of source water quality parameters, specifically TOC and bromide concentrations. In this, the threshold exceedances are modeled as Generalized Pareto Distribution (GPD) whose parameters vary as a function of climate and land surface variables - thus, enabling to capture the temporal nonstationarity. We apply these to model threshold exceedance of source water TOC and bromide concentrations at two locations with different climate and find very good performance.

Pre-mining trace element and radiation exposure to biota from a breccia pipe uranium mine in the Grand Canyon (Arizona, USA) watershed

USGS Publications Warehouse

Hinck, Jo E.; Cleveland, Danielle; Brumbaugh, William G.; Linder, Greg; Lankton, Julia S.

2017-01-01

The risks to wildlife and humans from uranium (U) mining in the Grand Canyon watershed are largely unknown. In addition to U, other co-occurring ore constituents contribute to risks to biological receptors depending on their toxicological profiles. This study characterizes the pre-mining concentrations of total arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), thallium (Tl), U, and zinc (Zn); radiation levels; and histopathology in biota (vegetation, invertebrates, amphibians, birds, and mammals) at the Canyon Mine. Gross alpha levels were below the reporting limit (4 pCi/g) in all samples, and gross beta levels were indicative of background in vegetation (<10–17 pCi/g) and rodents (<10–43.5 pCi/g). Concentrations of U, Tl, Pb, Ni, Cu, and As in vegetation downwind from the mine were likely the result of aeolian transport. Chemical concentrations in rodents and terrestrial invertebrates indicate that surface disturbance during mine construction has not resulted in statistically significant spatial differences in fauna concentrations adjacent to the mine. Chemical concentrations in egg contents and nestlings of non-aquatic birds were less than method quantification limits or did not exceed toxicity thresholds. Bioaccumulation of As, Pb, Se, Tl, and U was evident in Western spadefoot (Spea multiplicata) tadpoles from the mine containment pond; concentrations of As (28.9–31.4 μg/g) and Se (5.81–7.20 μg/g) exceeded toxicity values and were significantly greater than in tadpoles from a nearby water source. Continued evaluation of As and Se in biota inhabiting and forging in the mine containment pond is warranted as mining progresses.

Pre-mining trace element and radiation exposure to biota from a breccia pipe uranium mine in the Grand Canyon (Arizona, USA) watershed.

PubMed

Hinck, Jo Ellen; Cleveland, Danielle; Brumbaugh, William G; Linder, Greg; Lankton, Julia

2017-02-01

The risks to wildlife and humans from uranium (U) mining in the Grand Canyon watershed are largely unknown. In addition to U, other co-occurring ore constituents contribute to risks to biological receptors depending on their toxicological profiles. This study characterizes the pre-mining concentrations of total arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), thallium (Tl), U, and zinc (Zn); radiation levels; and histopathology in biota (vegetation, invertebrates, amphibians, birds, and mammals) at the Canyon Mine. Gross alpha levels were below the reporting limit (4 pCi/g) in all samples, and gross beta levels were indicative of background in vegetation (<10-17 pCi/g) and rodents (<10-43.5 pCi/g). Concentrations of U, Tl, Pb, Ni, Cu, and As in vegetation downwind from the mine were likely the result of aeolian transport. Chemical concentrations in rodents and terrestrial invertebrates indicate that surface disturbance during mine construction has not resulted in statistically significant spatial differences in fauna concentrations adjacent to the mine. Chemical concentrations in egg contents and nestlings of non-aquatic birds were less than method quantification limits or did not exceed toxicity thresholds. Bioaccumulation of As, Pb, Se, Tl, and U was evident in Western spadefoot (Spea multiplicata) tadpoles from the mine containment pond; concentrations of As (28.9-31.4 μg/g) and Se (5.81-7.20 μg/g) exceeded toxicity values and were significantly greater than in tadpoles from a nearby water source. Continued evaluation of As and Se in biota inhabiting and forging in the mine containment pond is warranted as mining progresses.

Oceanic Forcing of Ice-Sheet Retreat: West Antarctica and More

NASA Astrophysics Data System (ADS)

Alley, Richard B.; Anandakrishnan, Sridhar; Christianson, Knut; Horgan, Huw J.; Muto, Atsu; Parizek, Byron R.; Pollard, David; Walker, Ryan T.

2015-05-01

Ocean-ice interactions have exerted primary control on the Antarctic Ice Sheet and parts of the Greenland Ice Sheet, and will continue to do so in the near future, especially through melting of ice shelves and calving cliffs. Retreat in response to increasing marine melting typically exhibits threshold behavior, with little change for forcing below the threshold but a rapid, possibly delayed shift to a reduced state once the threshold is exceeded. For Thwaites Glacier, West Antarctica, the threshold may already have been exceeded, although rapid change may be delayed by centuries, and the reduced state will likely involve loss of most of the West Antarctic Ice Sheet, causing >3 m of sea-level rise. Because of shortcomings in physical understanding and available data, uncertainty persists about this threshold and the subsequent rate of change. Although sea-level histories and physical understanding allow the possibility that ice-sheet response could be quite fast, no strong constraints are yet available on the worst-case scenario. Recent work also suggests that the Greenland and East Antarctic Ice Sheets share some of the same vulnerabilities to shrinkage from marine influence.

The Irish Cost-Effectiveness Threshold: Does it Support Rational Rationing or Might it Lead to Unintended Harm to Ireland's Health System?

PubMed

O'Mahony, James F; Coughlan, Diarmuid

2016-01-01

Ireland is one of the few countries worldwide to have an explicit cost-effectiveness threshold. In 2012, an agreement between government and the pharmaceutical industry that provided substantial savings on existing medications set the threshold at €45,000/quality-adjusted life-year (QALY). This replaced a previously unofficial threshold of €20,000/QALY. According to the agreement, drugs within the threshold will be granted reimbursement, whereas those exceeding it may still be approved following further negotiation. A number of drugs far exceeding the threshold have been approved recently. The agreement only applies to pharmaceuticals. There are four reasons for concern regarding Ireland's threshold. The absence of an explicit threshold for non-drug interventions leaves it unclear if there is parity in willingness to pay across all interventions. As the threshold resembles a price floor rather than a ceiling, in principle it only offers a weak barrier to cost-ineffective interventions. It has no empirical basis. Finally, it is probably too high given recent estimates of a threshold for the UK based on the cost effectiveness of services forgone of approximately £13,000/QALY. An excessive threshold risks causing the Irish health system unintended harm. The lack of an empirically informed threshold means the policy recommendations of cost-effectiveness analysis cannot be considered as fully evidence- based rational rationing. Policy makers should consider these issues and recent Irish legislation that defined cost effectiveness in terms of the opportunity cost of services forgone when choosing what threshold to apply once the current industry agreement expires at the end of 2015

Calibration and validation of rainfall thresholds for shallow landslide forecasting in Sicily, southern Italy

NASA Astrophysics Data System (ADS)

Gariano, S. L.; Brunetti, M. T.; Iovine, G.; Melillo, M.; Peruccacci, S.; Terranova, O.; Vennari, C.; Guzzetti, F.

2015-01-01

Empirical rainfall thresholds are tools to forecast the possible occurrence of rainfall-induced shallow landslides. Accurate prediction of landslide occurrence requires reliable thresholds, which need to be properly validated before their use in operational warning systems. We exploited a catalogue of 200 rainfall conditions that have resulted in at least 223 shallow landslides in Sicily, southern Italy, in the 11-year period 2002-2011, to determine regional event duration-cumulated event rainfall (ED) thresholds for shallow landslide occurrence. We computed ED thresholds for different exceedance probability levels and determined the uncertainty associated to the thresholds using a consolidated bootstrap nonparametric technique. We further determined subregional thresholds, and we studied the role of lithology and seasonal periods in the initiation of shallow landslides in Sicily. Next, we validated the regional rainfall thresholds using 29 rainfall conditions that have resulted in 42 shallow landslides in Sicily in 2012. We based the validation on contingency tables, skill scores, and a receiver operating characteristic (ROC) analysis for thresholds at different exceedance probability levels, from 1% to 50%. Validation of rainfall thresholds is hampered by lack of information on landslide occurrence. Therefore, we considered the effects of variations in the contingencies and the skill scores caused by lack of information. Based on the results obtained, we propose a general methodology for the objective identification of a threshold that provides an optimal balance between maximization of correct predictions and minimization of incorrect predictions, including missed and false alarms. We expect that the methodology will increase the reliability of rainfall thresholds, fostering the operational use of validated rainfall thresholds in operational early warning system for regional shallow landslide forecasting.

Cytogenomics of hexavalent chromium (Cr6+) exposed cells: A comprehensive review

PubMed Central

Nigam, Akanksha; Priya, Shivam; Bajpai, Preeti; Kumar, Sushil

2014-01-01

The altered cellular gene expression profile is being hypothesized as the possible molecular basis navigating the onset or progress of various morbidities. This hypothesis has been evaluated here in respect of Cr6+ induced toxicity. Several studies using gene microarray show selective and strategic dysregulations of cellular genes and pathways induced by Cr6+. Relevant literature has been reviewed to unravel these changes in different test systems after exposure to Cr6+ and also to elucidate association if any, of the altered cytogenomics with Cr6+ induced toxicity or carcinogenicity. The aim was to verify the hypothesis for critical role of altered cytogenomics in onset of Cr6+ induced biological / clinical effects by identifying genes modulated commonly by the toxicant irrespective of test system or test concentrations / doses, and by scrutinizing their importance in regulation of the flow of mechanistically linked events crucial for resultant morbidities. Their probability as biomarkers to monitor the toxicant induced biological changes is speculative. The modulated genes have been found to cluster under the pathways that manage onset of oxidative stress, DNA damage, apoptosis, cell-cycle regulation, cytoskeleton, morphological changes, energy metabolism, biosynthesis, oncogenes, bioenergetics, and immune system critical for toxicity. In these studies, the identity of genes has been found to differ remarkably; albeit the trend of pathways’ dysregulation has been found to remain similar. We conclude that the intensity of dysregulation of genes or pathways involved in mechanistic events forms a sub-threshold or threshold level depending upon the dose and type (including speciation) of the toxicant, duration of exposure, type of target cells, and niche microenvironment of cells, and the intensity of sub-threshold or threshold level of the altered cytogenomics paves way in toxicant exposed cells eventually either to opt for reversal to differentiation and growth, or to result in toxicity like dedifferentiation and apoptosis, respectively. PMID:24820829

48 CFR 13.003 - Policy.

Code of Federal Regulations, 2010 CFR

2010-10-01

... acquisition procedures to the maximum extent practicable for all purchases of supplies or services not exceeding the simplified acquisition threshold (including purchases at or below the micro-purchase threshold... under part 8 (e.g., Federal Prison Industries, Committee for Purchase from People Who are Blind or...

Methods, apparatus and system for selective duplication of subtasks

DOEpatents

Andrade Costa, Carlos H.; Cher, Chen-Yong; Park, Yoonho; Rosenburg, Bryan S.; Ryu, Kyung D.

2016-03-29

A method for selective duplication of subtasks in a high-performance computing system includes: monitoring a health status of one or more nodes in a high-performance computing system, where one or more subtasks of a parallel task execute on the one or more nodes; identifying one or more nodes as having a likelihood of failure which exceeds a first prescribed threshold; selectively duplicating the one or more subtasks that execute on the one or more nodes having a likelihood of failure which exceeds the first prescribed threshold; and notifying a messaging library that one or more subtasks were duplicated.

Threshold Switchable Particles (TSPs) To Control Internal Hemorrhage

DTIC Science & Technology

2016-09-01

hemorrhage at local sites. Four collaborating laboratories worked together under this contract to define threshold levels of activators of blood clotting...such that the candidate clotting activators will circulate in the blood at a concentration below the threshold necessary to trigger clotting, but...accumulation of the activators at sites of internal injury/bleeding will cause the local concentration of clotting activators to exceed the clotting

48 CFR 217.7802 - Policy.

Code of Federal Regulations, 2010 CFR

2010-10-01

... considered include— (i) Satisfying customer requirements; (ii) Schedule; (iii) Cost effectiveness (taking... threshold through a non-DoD agency in any fiscal year only if the head of the non-DoD agency has certified... order exceeds the simplified acquisition threshold. These procedures shall include— (1) Evaluating...

48 CFR 41.401 - Monthly and annual review.

Code of Federal Regulations, 2010 CFR

2010-10-01

... values exceeding the simplified acquisition threshold, on an annual basis. Annual reviews of accounts with annual values at or below the simplified acquisition threshold shall be conducted when deemed... services to each facility under the utility's most economical, applicable rate and to examine competitive...

Prediction Uncertainty and Groundwater Management: Approaches to get the Most out of Probabilistic Outputs

NASA Astrophysics Data System (ADS)

Peeters, L. J.; Mallants, D.; Turnadge, C.

2017-12-01

Groundwater impact assessments are increasingly being undertaken in a probabilistic framework whereby various sources of uncertainty (model parameters, model structure, boundary conditions, and calibration data) are taken into account. This has resulted in groundwater impact metrics being presented as probability density functions and/or cumulative distribution functions, spatial maps displaying isolines of percentile values for specific metrics, etc. Groundwater management on the other hand typically uses single values (i.e., in a deterministic framework) to evaluate what decisions are required to protect groundwater resources. For instance, in New South Wales, Australia, a nominal drawdown value of two metres is specified by the NSW Aquifer Interference Policy as trigger-level threshold. In many cases, when drawdowns induced by groundwater extraction exceed two metres, "make-good" provisions are enacted (such as the surrendering of extraction licenses). The information obtained from a quantitative uncertainty analysis can be used to guide decision making in several ways. Two examples are discussed here: the first of which would not require modification of existing "deterministic" trigger or guideline values, whereas the second example assumes that the regulatory criteria are also expressed in probabilistic terms. The first example is a straightforward interpretation of calculated percentile values for specific impact metrics. The second examples goes a step further, as the previous deterministic thresholds do not currently allow for a probabilistic interpretation; e.g., there is no statement that "the probability of exceeding the threshold shall not be larger than 50%". It would indeed be sensible to have a set of thresholds with an associated acceptable probability of exceedance (or probability of not exceeding a threshold) that decreases as the impact increases. We here illustrate how both the prediction uncertainty and management rules can be expressed in a probabilistic framework, using groundwater metrics derived for a highly stressed groundwater system.

“Rational” Management of Dichlorophenols Biodegradation by the Microalga Scenedesmus obliquus

PubMed Central

Papazi, Aikaterini; Kotzabasis, Kiriakos

2013-01-01

The microalga Scenedesmus obliquus exhibited the ability to biodegrade dichlorophenols (dcps) under specific autotrophic and mixotrophic conditions. According to their biodegradability, the dichlorophenols used can be separated into three distinct groups. Group I (2,4-dcp and 2,6 dcp – no meta-substitution) consisted of quite easily degraded dichlorophenols, since both chloride substituents are in less energetically demanding positions. Group II (2,3-dcp, 2,5-dcp and 3,4-dcp – one meta-chloride) was less susceptible to biodegradation, since one of the two substituents, the meta one, required higher energy for C-Cl-bond cleavage. Group III (3,5-dcp – two meta-chlorides) could not be biodegraded, since both chlorides possessed the most energy demanding positions. In general, when the dcp-toxicity exceeded a certain threshold, the microalga increased the energy offered for biodegradation and decreased the energy invested for biomass production. As a result, the biodegradation per cell volume of group II (higher toxicity) was higher, than group I (lower toxicity) and the biodegradation of dichlorophenols (higher toxicity) was higher than the corresponding monochlorophenols (lower toxicity). The participation of the photosynthetic apparatus and the respiratory mechanism of microalga to biodegrade the group I and the group II, highlighted different bioenergetic strategies for optimal management of the balance between dcp-toxicity, dcp-biodegradability and culture growth. Additionally, we took into consideration the possibility that the intermediates of each dcp-biodegradation pathway could influence differently the whole biodegradation procedures. For this reason, we tested all possible combinations of phenolic intermediates to check cometabolic interactions. The present contribution bring out the possibility of microalgae to operate as “smart” bioenergetic “machines”, that have the ability to continuously “calculate” the energy reserves and “use” the most energetically advantageous dcp-biodegradation strategy. We tried to manipulate the above fact, changing the energy reserves and as a result the chosen strategy, in order to take advantage of their abilities in detoxifying the environment. PMID:23613903

"Rational" management of dichlorophenols biodegradation by the microalga Scenedesmus obliquus.

PubMed

Papazi, Aikaterini; Kotzabasis, Kiriakos

2013-01-01

The microalga Scenedesmus obliquus exhibited the ability to biodegrade dichlorophenols (dcps) under specific autotrophic and mixotrophic conditions. According to their biodegradability, the dichlorophenols used can be separated into three distinct groups. Group I (2,4-dcp and 2,6 dcp - no meta-substitution) consisted of quite easily degraded dichlorophenols, since both chloride substituents are in less energetically demanding positions. Group II (2,3-dcp, 2,5-dcp and 3,4-dcp - one meta-chloride) was less susceptible to biodegradation, since one of the two substituents, the meta one, required higher energy for C-Cl-bond cleavage. Group III (3,5-dcp - two meta-chlorides) could not be biodegraded, since both chlorides possessed the most energy demanding positions. In general, when the dcp-toxicity exceeded a certain threshold, the microalga increased the energy offered for biodegradation and decreased the energy invested for biomass production. As a result, the biodegradation per cell volume of group II (higher toxicity) was higher, than group I (lower toxicity) and the biodegradation of dichlorophenols (higher toxicity) was higher than the corresponding monochlorophenols (lower toxicity). The participation of the photosynthetic apparatus and the respiratory mechanism of microalga to biodegrade the group I and the group II, highlighted different bioenergetic strategies for optimal management of the balance between dcp-toxicity, dcp-biodegradability and culture growth. Additionally, we took into consideration the possibility that the intermediates of each dcp-biodegradation pathway could influence differently the whole biodegradation procedures. For this reason, we tested all possible combinations of phenolic intermediates to check cometabolic interactions. The present contribution bring out the possibility of microalgae to operate as "smart" bioenergetic "machines", that have the ability to continuously "calculate" the energy reserves and "use" the most energetically advantageous dcp-biodegradation strategy. We tried to manipulate the above fact, changing the energy reserves and as a result the chosen strategy, in order to take advantage of their abilities in detoxifying the environment.

A fresh look at road salt: aquatic toxicity and water-quality impacts on local, regional, and national scales.

PubMed

Corsi, Steven R; Graczyk, David J; Geis, Steven W; Booth, Nathaniel L; Richards, Kevin D

2010-10-01

A new perspective on the severity of aquatic toxicity impact of road salt was gained by a focused research effort directed at winter runoff periods. Dramatic impacts were observed on local, regional, and national scales. Locally, samples from 7 of 13 Milwaukee, Wisconsin area streams exhibited toxicity in Ceriodaphnia dubia and Pimephales promelas bioassays during road-salt runoff. Another Milwaukee stream was sampled from 1996 to 2008 with 72% of 37 samples exhibiting toxicity in chronic bioassays and 43% in acute bioassays. The maximum chloride concentration was 7730 mg/L. Regionally, in southeast Wisconsin, continuous specific conductance was monitored as a chloride surrogate in 11 watersheds with urban land use from 6.0 to 100%. Elevated specific conductance was observed between November and April at all sites, with continuing effects between May and October at sites with the highest specific conductance. Specific conductance was measured as high as 30,800 μS/cm (Cl = 11,200 mg/L). Chloride concentrations exceeded U.S. Environmental Protection Agency (USEPA) acute (860 mg/L) and chronic (230 mg/L) water-quality criteria at 55 and 100% of monitored sites, respectively. Nationally, U.S. Geological Survey historical data were examined for 13 northern and 4 southern metropolitan areas. Chloride concentrations exceeded USEPA water-quality criteria at 55% (chronic) and 25% (acute) of the 168 monitoring locations in northern metropolitan areas from November to April. Only 16% (chronic) and 1% (acute) of sites exceeded criteria from May to October. At southern sites, very few samples exceeded chronic water-quality criteria, and no samples exceeded acute criteria.

Rainfall thresholds for the initiation of debris flows at La Honda, California

USGS Publications Warehouse

Wilson, R.C.; Wieczorek, G.F.

1995-01-01

A simple numerical model, based on the physical analogy of a leaky barrel, can simulate significant features of the interaction between rainfall and shallow-hillslope pore pressures. The leaky-barrel-model threshold is consistent with, but slightly higher than, an earlier, purely empirical, threshold. The number of debris flows triggered by a storm can be related to the time and amount by which the leaky-barrel-model response exceeded the threshold during the storm. -from Authors

Accounting for differing exposure patterns between laboratory tests and the field in the assessment of long-term risks of pesticides to terrestrial vertebrates.

PubMed

Fischer, David L

2005-11-01

Long-term risks of pesticides to birds and mammals are currently assessed by comparing effects thresholds determined in chronic laboratory studies to exposure levels expected to occur in the field. However, there is often a mismatch between exposure patterns tested in the laboratory tests (exposure levels held constant) and those experienced by animals in the field (exposure levels varying over time). Three methods for addressing this problem are presented and discussed. Time-weighted averaging (TWA) converts a variable field exposure regime to a single value that can be compared directly to the laboratory test results. Body-burden modeling (BBM) is applied to both laboratory and field exposure regimes allowing a straightforward comparison of body residue levels expected for each situation. Temporal analysis (TA) uses expert judgment to decide if the length of time exposure exceeds a toxicity threshold is long enough to cause biologically significant effects. To reduce uncertainty in long-term assessments, the conduct of specialized laboratory tests in which test subjects are administered a time-varying exposure that mimics what occurs in the field should be considered. Such tests may also be useful testing the validity of each of these assessment methods.

Diversity of Rainfall Thresholds for early warning of hydro-geological disasters

NASA Astrophysics Data System (ADS)

De Luca, Davide L.; Versace, Pasquale

2017-06-01

For early warning of disasters induced by precipitation (such as floods and landslides), different kinds of rainfall thresholds are adopted, which vary from each other, on the basis on adopted hypotheses. In some cases, they represent the occurrence probability of an event (landslide or flood), in other cases the exceedance probability of a critical value for an assigned indicator I (a function of rainfall heights), and in further cases they only indicate the exceeding of a prefixed percentage a critical value for I, indicated as Icr. For each scheme, it is usual to define three different criticality levels (ordinary, moderate and severe), which are associated to warning levels, according to emergency plans. This work briefly discusses different schemes of rainfall thresholds, focusing attention on landslide prediction, with some applications to a real case study in Calabria region (southern Italy).

Impacts of pesticides in a Central California estuary.

PubMed

Anderson, Brian; Phillips, Bryn; Hunt, John; Siegler, Katie; Voorhees, Jennifer; Smalling, Kelly; Kuivila, Kathy; Hamilton, Mary; Ranasinghe, J Ananda; Tjeerdema, Ron

2014-03-01

Recent and past studies have documented the prevalence of pyrethroid and organophosphate pesticides in urban and agricultural watersheds in California. While toxic concentrations of these pesticides have been found in freshwater systems, there has been little research into their impacts in marine receiving waters. Our study investigated pesticide impacts in the Santa Maria River estuary, which provides critical habitat to numerous aquatic, terrestrial, and avian species on the central California coast. Runoff from irrigated agriculture constitutes a significant portion of Santa Maria River flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in this watershed. Our study extended into the Santa Maria watershed coastal zone and measured pesticide concentrations throughout the estuary, including the water column and sediments. Biological effects were measured at the organism and community levels. Results of this study suggest the Santa Maria River estuary is impacted by current-use pesticides. The majority of water samples were highly toxic to invertebrates (Ceriodaphnia dubia and Hyalella azteca), and chemistry evidence suggests toxicity was associated with the organophosphate pesticide chlorpyrifos, pyrethroid pesticides, or mixtures of both classes of pesticides. A high percentage of sediment samples were also toxic in this estuary, and sediment toxicity occurred when mixtures of chlorpyrifos and pyrethroid pesticides exceeded established toxicity thresholds. Based on a Relative Benthic Index, Santa Maria estuary stations where benthic macroinvertebrate communities were assessed were degraded. Impacts in the Santa Maria River estuary were likely due to the proximity of this system to Orcutt Creek, the tributary which accounts for most of the flow to the lower Santa Maria River. Water and sediment samples from Orcutt Creek were highly toxic to invertebrates due to mixtures of the same pesticides measured in the estuary. This study suggests that the same pyrethroid and organophosphate pesticides that have been shown to cause water and sediment toxicity in urban and agriculture water bodies throughout California, have the potential to affect estuarine habitats. The results establish baseline data in the Santa Maria River estuary to allow evaluation of ecosystem improvement as management initiatives to reduce pesticide runoff are implemented in this watershed.

Cognitive, emotion control, and motor performance of adolescents in the NCANDA study: Contributions from alcohol consumption, age, sex, ethnicity, and family history of addiction

PubMed Central

Sullivan, Edith V.; Brumback, Ty; Tapert, Susan F.; Fama, Rosemary; Prouty, Devin; Brown, Sandra A.; Cummins, Kevin; Thompson, Wesley K.; Colrain, Ian M.; Baker, Fiona C.; De Bellis, Michael D.; Hooper, Stephen R.; Clark, Duncan B.; Chung, Tammy; Nagel, Bonnie J.; Nichols, B. Nolan; Rohlfing, Torsten; Chu, Weiwei; Pohl, Kilian M.; Pfefferbaum, Adolf

2015-01-01

Objective To investigate development of cognitive and motor functions in healthy adolescents and to explore whether hazardous drinking affects the normal developmental course of those functions. Method Participants were 831 adolescents recruited across five United States sites of the National Consortium on Alcohol and NeuroDevelopment in Adolescence (NCANDA): 692 met criteria for no/low alcohol exposure, and 139 exceeded drinking thresholds. Cross-sectional, baseline data were collected with computerized and traditional neuropsychological tests assessing eight functional domains expressed as composite scores. General additive modeling evaluated factors potentially modulating performance (age, sex, ethnicity, socioeconomic status, and pubertal developmental stage). Results Older no/low-drinking participants achieved better scores than younger ones on five Accuracy composites (General Ability, Abstraction, Attention, Emotion, and Balance). Speeded responses for Attention, Motor Speed, and General Ability were sensitive to age and pubertal development. The exceeds-threshold group (accounting for age, sex, and other demographic factors) performed significantly below the no/low-drinking group on Balance accuracy and on General Ability, Attention, Episodic Memory, Emotion, and Motor speed scores and showed evidence for faster speed at the expense of accuracy. Delay Discounting performance was consistent with poor impulse control in the younger no/low drinkers and in exceeds-threshold drinkers regardless of age. Conclusions Higher achievement with older age and pubertal stage in General Ability, Abstraction, Attention, Emotion, and Balance suggests continued functional development through adolescence, possibly supported by concurrently maturing frontal, limbic, and cerebellar brain systems. Whether low scores by the exceeds-threshold group resulted from drinking or from other pre-existing factors requires longitudinal study. PMID:26752122

Cognitive, emotion control, and motor performance of adolescents in the NCANDA study: Contributions from alcohol consumption, age, sex, ethnicity, and family history of addiction.

PubMed

Sullivan, Edith V; Brumback, Ty; Tapert, Susan F; Fama, Rosemary; Prouty, Devin; Brown, Sandra A; Cummins, Kevin; Thompson, Wesley K; Colrain, Ian M; Baker, Fiona C; De Bellis, Michael D; Hooper, Stephen R; Clark, Duncan B; Chung, Tammy; Nagel, Bonnie J; Nichols, B Nolan; Rohlfing, Torsten; Chu, Weiwei; Pohl, Kilian M; Pfefferbaum, Adolf

2016-05-01

To investigate development of cognitive and motor functions in healthy adolescents and to explore whether hazardous drinking affects the normal developmental course of those functions. Participants were 831 adolescents recruited across 5 United States sites of the National Consortium on Alcohol and NeuroDevelopment in Adolescence 692 met criteria for no/low alcohol exposure, and 139 exceeded drinking thresholds. Cross-sectional, baseline data were collected with computerized and traditional neuropsychological tests assessing 8 functional domains expressed as composite scores. General additive modeling evaluated factors potentially modulating performance (age, sex, ethnicity, socioeconomic status, and pubertal developmental stage). Older no/low-drinking participants achieved better scores than younger ones on 5 accuracy composites (general ability, abstraction, attention, emotion, and balance). Speeded responses for attention, motor speed, and general ability were sensitive to age and pubertal development. The exceeds-threshold group (accounting for age, sex, and other demographic factors) performed significantly below the no/low-drinking group on balance accuracy and on general ability, attention, episodic memory, emotion, and motor speed scores and showed evidence for faster speed at the expense of accuracy. Delay Discounting performance was consistent with poor impulse control in the younger no/low drinkers and in exceeds-threshold drinkers regardless of age. Higher achievement with older age and pubertal stage in general ability, abstraction, attention, emotion, and balance suggests continued functional development through adolescence, possibly supported by concurrently maturing frontal, limbic, and cerebellar brain systems. Determination of whether low scores by the exceeds-threshold group resulted from drinking or from other preexisting factors requires longitudinal study. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Concentrations of dioxins and dioxin-like PCBs in feed materials in the Netherlands, 2001-11.

PubMed

Adamse, Paulien; Van der Fels-Klerx, H J Ine; Schoss, Stefanie; de Jong, Jacob; Hoogenboom, Ron L A P

2015-01-01

This study aimed to obtain insights into contamination of feed materials used in the Netherlands with dioxins (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like polychlorinated biphenyls (PCBs). Monitoring results from the period 2001-11, covering in total 4938 samples, were statistically analysed and evaluated against the statutory limits set at the beginning or during this period. The percentage of samples exceeding maximum levels set within the European Union for either dioxins or the sum of dioxins and dioxin-like PCBs were below 1% for most feed categories, except for fish meal (4.1%), clay minerals (binders and anti-caking agents) (3.4%), and vegetable oils and byproducts (1.7%). For most feed categories, non-compliance with the action threshold (roughly 33% lower than maximum levels) for either dioxins or dioxin-like PCBs was up to three times higher than non-compliance with the respective maximum levels. Exceedance of action thresholds was just above 1% for animal fat, pre-mixtures and feed materials of plant origin excluding vegetable oils. For the categories fish meal, clay minerals, and vegetable oils and byproducts, the action thresholds were exceeded by 5.0%, 9.8% and 3.0% of the samples, respectively. In general, the percentages of samples that exceeded the action thresholds and maximum levels were lower than those reported for the European Union by the European Food Safety Authority (EFSA). In most of the feed materials, there seems to be a decreasing trend in concentrations of dioxins or dioxin-like PCBs over the years. However, a lowering of the limits of quantification during this period and the low concentrations in most samples precludes drawing strong conclusions.

Comparisons of two moments‐based estimators that utilize historical and paleoflood data for the log Pearson type III distribution

USGS Publications Warehouse

England, John F.; Salas, José D.; Jarrett, Robert D.

2003-01-01

The expected moments algorithm (EMA) [Cohn et al., 1997] and the Bulletin 17B [Interagency Committee on Water Data, 1982] historical weighting procedure (B17H) for the log Pearson type III distribution are compared by Monte Carlo computer simulation for cases in which historical and/or paleoflood data are available. The relative performance of the estimators was explored for three cases: fixed‐threshold exceedances, a fixed number of large floods, and floods generated from a different parent distribution. EMA can effectively incorporate four types of historical and paleoflood data: floods where the discharge is explicitly known, unknown discharges below a single threshold, floods with unknown discharge that exceed some level, and floods with discharges described in a range. The B17H estimator can utilize only the first two types of historical information. Including historical/paleoflood data in the simulation experiments significantly improved the quantile estimates in terms of mean square error and bias relative to using gage data alone. EMA performed significantly better than B17H in nearly all cases considered. B17H performed as well as EMA for estimating X100 in some limited fixed‐threshold exceedance cases. EMA performed comparatively much better in other fixed‐threshold situations, for the single large flood case, and in cases when estimating extreme floods equal to or greater than X500. B17H did not fully utilize historical information when the historical period exceeded 200 years. Robustness studies using GEV‐simulated data confirmed that EMA performed better than B17H. Overall, EMA is preferred to B17H when historical and paleoflood data are available for flood frequency analysis.

Comparisons of two moments-based estimators that utilize historical and paleoflood data for the log Pearson type III distribution

NASA Astrophysics Data System (ADS)

England, John F.; Salas, José D.; Jarrett, Robert D.

2003-09-01

The expected moments algorithm (EMA) [, 1997] and the Bulletin 17B [, 1982] historical weighting procedure (B17H) for the log Pearson type III distribution are compared by Monte Carlo computer simulation for cases in which historical and/or paleoflood data are available. The relative performance of the estimators was explored for three cases: fixed-threshold exceedances, a fixed number of large floods, and floods generated from a different parent distribution. EMA can effectively incorporate four types of historical and paleoflood data: floods where the discharge is explicitly known, unknown discharges below a single threshold, floods with unknown discharge that exceed some level, and floods with discharges described in a range. The B17H estimator can utilize only the first two types of historical information. Including historical/paleoflood data in the simulation experiments significantly improved the quantile estimates in terms of mean square error and bias relative to using gage data alone. EMA performed significantly better than B17H in nearly all cases considered. B17H performed as well as EMA for estimating X100 in some limited fixed-threshold exceedance cases. EMA performed comparatively much better in other fixed-threshold situations, for the single large flood case, and in cases when estimating extreme floods equal to or greater than X500. B17H did not fully utilize historical information when the historical period exceeded 200 years. Robustness studies using GEV-simulated data confirmed that EMA performed better than B17H. Overall, EMA is preferred to B17H when historical and paleoflood data are available for flood frequency analysis.

40 CFR 372.28 - Lower thresholds for chemicals of special concern.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 29 2013-07-01 2013-07-01 false Lower thresholds for chemicals of... (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.28 Lower thresholds for chemicals of special...

Contributions to the Nutrient Toolbox: Identifying Drivers, Nutrient Sources, and Attribution of Exceedances

EPA Science Inventory

Nutrients are a leading cause of impairments in the United States, and as a result tools are needed to identify drivers of nutrients and response variables (such as chlorophyll a), nutrient sources, and identify causes of exceedances of water quality thresholds. This presentatio...

A new concept for the environmental risk assessment of poorly water soluble compounds and its application to consumer products.

PubMed

Tolls, Johannes; Müller, Martin; Willing, Andreas; Steber, Josef

2009-07-01

Many consumer products contain lipophilic, poorly soluble ingredients representing large-volume substances whose aquatic toxicity cannot be adequately determined with standard methods for a number of reasons. In such cases, a recently developed approach can be used to define an aquatic exposure threshold of no concern (ETNCaq; i.e., a concentration below which no adverse affects on the environment are to be expected). A risk assessment can be performed by comparing the ETNCaq value with the aquatic exposure levels of poorly soluble substances. Accordingly, the aquatic exposure levels of substances with water solubility below the ETNCaq will not exceed the ecotoxicological no-effect concentration; therefore, their risk can be assessed as being negligible. The ETNCaq value relevant for substances with a narcotic mode of action is 1.9 microg/L. To apply the above risk assessment strategy, the solubility in water needs to be known. Most frequently, this parameter is estimated by means of quantitative structure/activity relationships based on the log octanol-water partition coefficient (log Kow). The predictive value of several calculation models for water solubility has been investigated by this method with the use of more recent experimental solubility data for lipophilic compounds. A linear regression model was shown to be the most suitable for providing correct predictions without underestimation of real water solubility. To define a log Kow threshold suitable for reliably predicting a water solubility of less than 1.9 microg/L, a confidence limit was established by statistical comparison of the experimental solubility data with their log Kow. It was found that a threshold of log Kow = 7 generally allows discrimination between substances with solubility greater than and less than 1.9 microg/L. Accordingly, organic substances with a baseline toxicity and log Kow > 7 do not require further testing to prove that they have low environmental risk. In applying this concept, the uncertainty of the prediction of water solubility can be accounted for. If the predicted solubility in water is to be below ETNCaq with a probability of 95%, the corresponding log Kow value is 8.

76 FR 22070 - Federal Acquisition Regulation; Service Contracts Reporting Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-20

... be required to report this information if the order meets the thresholds established in FAR 4.1603 (e... Definitions. 4.1602 Applicability. 4.1603 Contractor reporting requirements. 4.1604 Contracting officer..., and orders for services that meet or exceed the thresholds at 4.1603; and (3) Contractors and first...

Assessing Personal Qualities in Medical School Admissions.

ERIC Educational Resources Information Center

Albanese, Mark A.; Snow, Mikel H.; Skochelak, Susan E.; Huggett, Kathryn N.; Farrell, Philip M.

2003-01-01

Analyzes the challenges to using academic measures (MCAT scores and GPAs) as thresholds for medical school admissions and, for applicants exceeding the threshold, using personal qualities for admission decisions; reviews the literature on using the medical school interview and other admission data to assess personal qualities of applicants;…

42 CFR § 414.1425 - Qualifying APM participant determination: In general.

Code of Federal Regulations, 2010 CFR

2017-10-01

..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) PAYMENT FOR PART B MEDICAL AND OTHER HEALTH SERVICES Merit-Based Incentive Payment System and Alternative Payment Model Incentive... Score that meets or exceeds the corresponding QP payment amount threshold or QP patient count threshold...

No minimum threshold for ozone-induced changes in soybean canopy fluxes

USDA-ARS?s Scientific Manuscript database

Tropospheric ozone concentrations [O3] are increasing at rates that exceed any other pollutant. This highly reactive gas drives reductions in plant productivity and canopy water use while also increasing canopy temperature and sensible heat flux. It is not clear whether a minimum threshold of ozone ...

Threshold friction velocity of soils within the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Wind erosion only occurs when the friction velocity exceeds the threshold friction velocity (TFV) of the surface. The TFV of loessial soils commonly found across the Columbia Plateau region of the U.S. Pacific Northwest is virtually unknown even though these soils are highly erodible and a source of...

Threshold friction velocity influenced by wetness of soils within the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Windblown dust impacts air quality in the Columbia Plateau of the U.S. Pacific Northwest. Wind erosion of agricultural lands, which is the predominate source of windblown dust in the region, occurs when the friction velocity exceeds the threshold friction velocity (TFV) of the surface. Soil moisture...

Threshold friction velocity of crusted windblown soils in the Columbia Plateau

USDA-ARS?s Scientific Manuscript database

Wind erosion processes are governed by soil physical properties and surface characteristics. Erosion is initiated when the friction velocity exceeds the threshold friction velocity (u*t) of soils. Although u*t is influenced by soil physical properties such as wetness and crusting, there is little in...

Hazard Classification of Household Chemical Products in Korea according to the Globally Harmonized System of Classification and labeling of Chemicals.

PubMed

Kim, Kyung-Hee; Song, Dae-Jong; Yu, Myeong-Hyun; Park, Yuon-Shin; Noh, Hye-Ran; Kim, Hae-Joon; Choi, Jae-Wook

2013-07-16

This study was conducted to review the validity of the need for the application of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) to household chemical products in Korea. The study also aimed to assess the severity of health and environmental hazards of household chemical products using the GHS. 135 products were classified as 'cleaning agents and polishing agents' and 98 products were classified as 'bleaches, disinfectants, and germicides.' The current status of carcinogenic classification of GHS and carcinogenicity was examined for 272 chemical substances contained in household chemical products by selecting the top 11 products for each of the product categories. In addition, the degree of toxicity was assessed through analysis of whether the standard of the Republic of Korea's regulations on household chemical products had been exceeded or not. According to GHS health and environmental hazards, "acute toxicity (oral)" was found to be the highest for two product groups, 'cleaning agents and polishing agents', and 'bleaches, disinfectants, and germicides' (result of classification of 233 household chemical products) at 37.8% and 52.0% respectively. In an analysis of carcinogenicity assuming a threshold of IARC 2B for the substances in household chemical products, we found 'cleaning agents and polishing agents' to contain 12 chemical substances and 'bleaches, disinfectants, and germicides' 11 chemical substances. Some of the household chemical products were found to have a high hazard level including acute toxicity and germ cell mutagenicity, carcinogenicity, and reproductive toxicity. Establishing a hazard information delivery system including the application of GHS to household chemical products in Korea is urgent as well.

Toxicity risk assessment of mercury, DDT and arsenic legacy pollution in sediments: A triad approach under low concentration conditions.

PubMed

Marziali, L; Rosignoli, F; Drago, A; Pascariello, S; Valsecchi, L; Rossaro, B; Guzzella, L

2017-09-01

The determination of sediment toxicity is challenging due to site-specific factors affecting pollutants distribution and bioavailability, especially when contamination levels are close to expected non-effect concentrations. Different lines of evidence and sensitive tools are necessary for a proper toxicity risk assessment. We examined the case study of the Toce River (Northern Italy), where past industrial activities determined Hg, DDT and As enrichment in sediments. A triad approach comprising chemical, ecotoxicological and ecological analyses (benthic invertebrates) was carried out for risk assessment of residual contamination in river sediments. A "blank" site upstream from the industrial site was selected to compare the other sites downstream. Sediment, water and benthic invertebrate samplings were carried out following standard protocols. Results emphasized that despite the emissions of the industrial site ceased about 20years ago, sediments in the downstream section of the river remain contaminated by Hg, DDT and As with concentrations exceeding Threshold Effect Concentrations. A chronic whole-sediment test with Chironomus riparius showed decreased development rate and a lower number of eggs per mass in the contaminated sediments. Benthic community was analyzed with the calculation of integrated (STAR_ICMi) and stressor-specific metrics (SPEAR pesticide and mean sensitivity to Hg), but no significant differences were found between upstream and downstream sites. On the other hand, multivariate analysis (partial Redundancy Analysis and variation partitioning) emphasized a slight impact on invertebrate community, accounting for 5% variation in taxa composition. Results show that legacy contaminants in sediments, even at low concentrations, may be bioavailable and possibly toxic for benthic invertebrates. At low concentration levels, sensitive and site-specific tools need to be developed for a proper risk analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Transformation-Dissolution Reactions Partially Explain Adverse Effects of Metallic Silver Nanoparticles to Soil Nitrification in Different Soils.

PubMed

Bollyn, Jessica; Willaert, Bernd; Kerré, Bart; Moens, Claudia; Arijs, Katrien; Mertens, Jelle; Leverett, Dean; Oorts, Koen; Smolders, Erik

2018-04-25

Risk assessment of metallic nanoparticles (NP) is critically affected by the concern that toxicity goes beyond that of the metallic ion. This study addressed this concern for soils with silver (Ag)-NP using the Ag-sensitive nitrification assay. Three agricultural soils (A,B,C) were spiked with equivalent Ag doses of either Ag-NP (d = 13 nm) or AgNO 3 . Soil solution was isolated and monitored over 97 days with due attention to accurate Ag fractionation at low (∼10 µg L -1 ) Ag concentrations. Truly dissolved (<1 kDa) Ag in the AgNO 3 -amended soils decreased with reaction half-lives of 4 to 22 days depending on the soil, denoting important Ag-ageing reactions. In contrast, truly dissolved Ag in Ag-NP-amended soils first increased by dissolution and subsequently decreased by ageing; the concentration never exceeding that in the AgNO 3 -amended soils. The half-lives of Ag-NP transformation-dissolution were about 4 days (soils A&B) and 36 days (soil C). The Ag toxic thresholds (EC10, mg Ag kg -1 soil) of nitrification, either evaluated at 21 or 35 days after spiking, were similar between the two Ag forms (soils A&B) but were factors 3 to 8 lower for AgNO 3 than for Ag-NP (soil C), largely corroborating with dissolution differences. This fate and bio-assay showed that Ag-NPs are not more toxic than AgNO 3 at equivalent total soil Ag concentrations and that differences in Ag-dissolution at least partially explain toxicity differences between the forms and among soils. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Lithium Poisoning.

PubMed

Baird-Gunning, Jonathan; Lea-Henry, Tom; Hoegberg, Lotte C G; Gosselin, Sophie; Roberts, Darren M

2017-05-01

Lithium is a commonly prescribed treatment for bipolar affective disorder. However, treatment is complicated by lithium's narrow therapeutic index and the influence of kidney function, both of which increase the risk of toxicity. Therefore, careful attention to dosing, monitoring, and titration is required. The cause of lithium poisoning influences treatment and 3 patterns are described: acute, acute-on-chronic, and chronic. Chronic poisoning is the most common etiology, is usually unintentional, and results from lithium intake exceeding elimination. This is most commonly due to impaired kidney function caused by volume depletion from lithium-induced nephrogenic diabetes insipidus or intercurrent illnesses and is also drug-induced. Lithium poisoning can affect multiple organs; however, the primary site of toxicity is the central nervous system and clinical manifestations vary from asymptomatic supratherapeutic drug concentrations to clinical toxicity such as confusion, ataxia, or seizures. Lithium poisoning has a low mortality rate; however, chronic lithium poisoning can require a prolonged hospital length of stay from impaired mobility and cognition and associated nosocomial complications. Persistent neurological deficits, in particular cerebellar, are described and the incidence and risk factors for its development are poorly understood, but it appears to be uncommon in uncomplicated acute poisoning. Lithium is readily dialyzable, and rationale support extracorporeal treatments to reduce the risk or the duration of toxicity in high-risk exposures. There is disagreement in the literature regarding factors that define patients most likely to benefit from treatments that enhance lithium elimination, including specific plasma lithium concentration thresholds. In the case of extracorporeal treatments, there are observational data in its favor, without evidence from randomized controlled trials (none have been performed), which may lead to conservative practices and potentially unnecessary interventions in some circumstances. More data are required to define the risk-benefit of extracorporeal treatments and their use (modality, duration) in the management of lithium poisoning.

Hazard Classification of Household Chemical Products in Korea according to the Globally Harmonized System of Classification and labeling of Chemicals

PubMed Central

2013-01-01

Objectives This study was conducted to review the validity of the need for the application of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) to household chemical products in Korea. The study also aimed to assess the severity of health and environmental hazards of household chemical products using the GHS. Methods 135 products were classified as ‘cleaning agents and polishing agents’ and 98 products were classified as ‘bleaches, disinfectants, and germicides.’ The current status of carcinogenic classification of GHS and carcinogenicity was examined for 272 chemical substances contained in household chemical products by selecting the top 11 products for each of the product categories. In addition, the degree of toxicity was assessed through analysis of whether the standard of the Republic of Korea’s regulations on household chemical products had been exceeded or not. Results According to GHS health and environmental hazards, “acute toxicity (oral)” was found to be the highest for two product groups, ‘cleaning agents and polishing agents’, and ‘bleaches, disinfectants, and germicides’ (result of classification of 233 household chemical products) at 37.8% and 52.0% respectively. In an analysis of carcinogenicity assuming a threshold of IARC 2B for the substances in household chemical products, we found ‘cleaning agents and polishing agents’ to contain 12 chemical substances and ‘bleaches, disinfectants, and germicides’ 11 chemical substances. Conclusion Some of the household chemical products were found to have a high hazard level including acute toxicity and germ cell mutagenicity, carcinogenicity, and reproductive toxicity. Establishing a hazard information delivery system including the application of GHS to household chemical products in Korea is urgent as well. PMID:24472347

Anaerobic digestion of nitrogen rich poultry manure: Impact of thermophilic biogas process on metal release and microbial resistances.

PubMed

Anjum, Reshma; Grohmann, Elisabeth; Krakat, Niclas

2017-02-01

Poultry manure is a nitrogen rich fertilizer, which is usually recycled and spread on agricultural fields. Due to its high nutrient content, chicken manure is considered to be one of the most valuable animal wastes as organic fertilizer. However, when chicken litter is applied in its native form, concerns are raised as such fertilizers also include high amounts of antibiotic resistant pathogenic Bacteria and heavy metals. We studied the impact of an anaerobic thermophilic digestion process on poultry manure. Particularly, microbial antibiotic resistance profiles, mobile genetic elements promoting the resistance dissemination in the environment as well as the presence of heavy metals were focused in this study. The initiated heat treatment fostered a community shift from pathogenic to less pathogenic bacterial groups. Phenotypic and molecular studies demonstrated a clear reduction of multiple resistant pathogens and self-transmissible plasmids in the heat treated manure. That treatment also induced a higher release of metals and macroelements. Especially, Zn and Cu exceeded toxic thresholds. Although the concentrations of a few metals reached toxic levels after the anaerobic thermophilic treatment, the quality of poultry manure as organic fertilizer may raise significantly due to the elimination of antibiotic resistance genes (ARG) and self-transmissible plasmids. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessing the Risk of Engineered Nanomaterials in the Environment: Development and Application of the nanoFate Model.

PubMed

Garner, Kendra L; Suh, Sangwon; Keller, Arturo A

2017-05-16

We developed a dynamic multimedia fate and transport model (nanoFate) to predict the time-dependent accumulation of metallic engineered nanomaterials (ENMs) across environmental media. nanoFate considers a wider range of processes and environmental subcompartments than most previous models and considers ENM releases to compartments (e.g., urban, agriculture) in a manner that reflects their different patterns of use and disposal. As an example, we simulated ten years of release of nano CeO 2 , CuO, TiO 2 , and ZnO in the San Francisco Bay area. Results show that even soluble metal oxide ENMs may accumulate as nanoparticles in the environment in sufficient concentrations to exceed the minimum toxic threshold in freshwater and some soils, though this is more likely with high-production ENMs such as TiO 2 and ZnO. Fluctuations in weather and release scenario may lead to circumstances where predicted ENM concentrations approach acute toxic concentrations. The fate of these ENMs is to mostly remain either aggregated or dissolved in agricultural lands receiving biosolids and in freshwater or marine sediments. Comparison to previous studies indicates the importance of some key model aspects including climatic and temporal variations, how ENMs may be released into the environment, and the effect of compartment composition on predicted concentrations.

Lead in the tissues of terrestrial raptors in southern Ontario, Canada, 1995-2001.

PubMed

Martin, Pamela A; Campbell, Douglas; Hughes, Kimberley; McDaniel, Tana

2008-02-25

Terrestrial raptors which feed on upland hunted game species may increase their risk to lead exposure and lead poisoning by ingesting lead shot found in the tissues of prey. Lead exposure in 225 individuals of nineteen species of terrestrial raptors, collected as carcasses in southern Ontario from 1995-2001, was examined through the analysis of bone, liver and kidney tissues. In this study, one red-tailed hawk contained liver lead concentrations and exhibited signs consistent with lead poisoning. Liver and kidney concentrations of one turkey vulture were also significantly higher than that associated with subclinical effects. This same bird, plus another turkey vulture and a northern harrier, had elevated bone lead concentrations (>10 microg/g dw) associated with possible toxicity. Turkey vultures had the highest mean concentrations of lead in bone and kidney compared to other raptor species. While it appeared only a single bird suffered acute lead poisoning, lead levels exceeded threshold concentrations associated with subclinical or acute toxicity in 4 of 225, almost 2%, of terrestrial raptors assessed. Given the association between lead exposure in raptors and hunting of game species reported in other studies, the continued use of lead shot for upland hunting in Ontario likely remains as one of the primary sources of lead and a continued risk to these birds of prey.

Concentrations of metals and trace elements in blood of spectacled and king eiders in northern Alaska, USA

USGS Publications Warehouse

Wilson, Heather M.; Petersen, Margaret R.; Troy, Declan

2004-01-01

In 1996, we measured concentrations of arsenic, barium, cadmium, lead, mercury, and selenium in blood of adult king (Somateria spectabilis) and spectacled (Somateria fischeri) eiders and duckling spectacled eiders from northern Alaska, USA. Concentrations of selenium exceeded background levels in all adults sampled and 9 of 12 ducklings. Mercury was detected in all adult spectacled eiders and 5 of 12 ducklings. Lead concentrations were above the clinical toxicity threshold in one duckling (0.64 ppm) and two adult female spectacled eiders (0.54 and 4.30 ppm). Concentrations of cadmium and mercury varied between species; barium, cadmium, mercury, and selenium varied between sexes. In female spectacled eiders, mercury concentrations increased during the breeding season and barium and selenium levels decreased through the breeding season. Selenium declined at 2.3 ± 0.9% per day and levels were lower in spectacled eiders arriving to the breeding grounds in northern Alaska than in western Alaska. The variation in selenium levels between breeding areas may be explained by differences in timing and routes of spring migration. Most trace elements for which we tested were not at levels currently considered toxic to marine birds. However, the presence of mercury and elevated lead in ducklings and adult female spectacled eiders suggests these metals are available on the breeding grounds.

INEEL AIR MODELING PROTOCOL ext

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. S. Staley; M. L. Abbott; P. D. Ritter

2004-12-01

Various laws stemming from the Clean Air Act of 1970 and the Clean Air Act amendments of 1990 require air emissions modeling. Modeling is used to ensure that air emissions from new projects and from modifications to existing facilities do not exceed certain standards. For radionuclides, any new airborne release must be modeled to show that downwind receptors do not receive exposures exceeding the dose limits and to determine the requirements for emissions monitoring. For criteria and toxic pollutants, emissions usually must first exceed threshold values before modeling of downwind concentrations is required. This document was prepared to provide guidancemore » for performing environmental compliance-driven air modeling of emissions from Idaho National Engineering and Environmental Laboratory facilities. This document assumes that the user has experience in air modeling and dose and risk assessment. It is not intended to be a "cookbook," nor should all recommendations herein be construed as requirements. However, there are certain procedures that are required by law, and these are pointed out. It is also important to understand that air emissions modeling is a constantly evolving process. This document should, therefore, be reviewed periodically and revised as needed. The document is divided into two parts. Part A is the protocol for radiological assessments, and Part B is for nonradiological assessments. This document is an update of and supersedes document INEEL/INT-98-00236, Rev. 0, INEEL Air Modeling Protocol. This updated document incorporates changes in some of the rules, procedures, and air modeling codes that have occurred since the protocol was first published in 1998.« less

Bayesian inference and assessment for rare-event bycatch in marine fisheries: a drift gillnet fishery case study.

PubMed

Martin, Summer L; Stohs, Stephen M; Moore, Jeffrey E

2015-03-01

Fisheries bycatch is a global threat to marine megafauna. Environmental laws require bycatch assessment for protected species, but this is difficult when bycatch is rare. Low bycatch rates, combined with low observer coverage, may lead to biased, imprecise estimates when using standard ratio estimators. Bayesian model-based approaches incorporate uncertainty, produce less volatile estimates, and enable probabilistic evaluation of estimates relative to management thresholds. Here, we demonstrate a pragmatic decision-making process that uses Bayesian model-based inferences to estimate the probability of exceeding management thresholds for bycatch in fisheries with < 100% observer coverage. Using the California drift gillnet fishery as a case study, we (1) model rates of rare-event bycatch and mortality using Bayesian Markov chain Monte Carlo estimation methods and 20 years of observer data; (2) predict unobserved counts of bycatch and mortality; (3) infer expected annual mortality; (4) determine probabilities of mortality exceeding regulatory thresholds; and (5) classify the fishery as having low, medium, or high bycatch impact using those probabilities. We focused on leatherback sea turtles (Dermochelys coriacea) and humpback whales (Megaptera novaeangliae). Candidate models included Poisson or zero-inflated Poisson likelihood, fishing effort, and a bycatch rate that varied with area, time, or regulatory regime. Regulatory regime had the strongest effect on leatherback bycatch, with the highest levels occurring prior to a regulatory change. Area had the strongest effect on humpback bycatch. Cumulative bycatch estimates for the 20-year period were 104-242 leatherbacks (52-153 deaths) and 6-50 humpbacks (0-21 deaths). The probability of exceeding a regulatory threshold under the U.S. Marine Mammal Protection Act (Potential Biological Removal, PBR) of 0.113 humpback deaths was 0.58, warranting a "medium bycatch impact" classification of the fishery. No PBR thresholds exist for leatherbacks, but the probability of exceeding an anticipated level of two deaths per year, stated as part of a U.S. Endangered Species Act assessment process, was 0.0007. The approach demonstrated here would allow managers to objectively and probabilistically classify fisheries with respect to bycatch impacts on species that have population-relevant mortality reference points, and declare with a stipulated level of certainty that bycatch did or did not exceed estimated upper bounds.

Heavy Metal Contents of Soils, Durum and Bread Wheats in Harran Plain, Southeast Turkey

NASA Astrophysics Data System (ADS)

Büyükkılıç Yanardaǧ, Asuman

2013-04-01

Soils are vital for regulating the biological effects and mobility of metals in nature. Iron and zinc are some of the essential nutrients for plants and animals, while other metals are potentially toxic such as lead and cadmium. Toxic heavy metals (HMs) can be taken up easily by organisms. HMs inputs to soil via the application of metal-contained fertilizers often exceed outputs in crops and drainage waters, thus toxic HMs content in many agricultural soils tends to be gradually increasing. Thus adverse human health effects due to soil-plant and plant-human transfer of HMs have been enhanced. HMs may cause harmful effects on human health due to the ingestion of food grain grown in soils. The objectives of this study were (1) to understand the chemistry of metals in soils for managing their agricultural and ecological impacts, (2) to identify metal uptakes of different genotypes of wheat. Concentrations of HMs (Cd, Zn, Ni, Mn, Cu, Mo, Pb) in wheat were investigated in different agricultural areas in Southeast, Turkey. The results showed that concentrations of HMs were in following order: Mn>Ni>Zn>Cu>Pb>Mo>Cd in surface and next to surface soil and Mn>Zn>Cu>Pb> Ni>Mo>Cd in wheat, respectively. HMs concentrations of several soil samples exceeded the permissible limits of Europe standard except for Ni and Mn. In addition, concentration of Cd, Zn, Cu, and Pb were higher in bread wheat than in durum wheat; however, concentration of Mn, Ni and Mo were higher in durum wheat than in bread wheat. Unusual amount of heavy metals found in some fertilizers used in the Southeast region of Turkey, it becomes an important subject to determine the amount of metals added to the soil every year. Heavy metals uptake by plants still remains to be an interest for researchers. As the heavy metals contents of plants were below the threshold levels, we conclude that the quality of wheat is high and it should receive attention in national and international markets. Keywords: Heavy Metals (HMs), Soil, Durum and Bread Wheat, Fertilizers.

A Fresh Look at Road Salt: Aquatic Toxicity and Water-Quality Impacts on Local, Regional, and National Scales

PubMed Central

2010-01-01

A new perspective on the severity of aquatic toxicity impact of road salt was gained by a focused research effort directed at winter runoff periods. Dramatic impacts were observed on local, regional, and national scales. Locally, samples from 7 of 13 Milwaukee, Wisconsin area streams exhibited toxicity in Ceriodaphnia dubia and Pimephales promelas bioassays during road-salt runoff. Another Milwaukee stream was sampled from 1996 to 2008 with 72% of 37 samples exhibiting toxicity in chronic bioassays and 43% in acute bioassays. The maximum chloride concentration was 7730 mg/L. Regionally, in southeast Wisconsin, continuous specific conductance was monitored as a chloride surrogate in 11 watersheds with urban land use from 6.0 to 100%. Elevated specific conductance was observed between November and April at all sites, with continuing effects between May and October at sites with the highest specific conductance. Specific conductance was measured as high as 30 800 μS/cm (Cl = 11 200 mg/L). Chloride concentrations exceeded U.S. Environmental Protection Agency (USEPA) acute (860 mg/L) and chronic (230 mg/L) water-quality criteria at 55 and 100% of monitored sites, respectively. Nationally, U.S. Geological Survey historical data were examined for 13 northern and 4 southern metropolitan areas. Chloride concentrations exceeded USEPA water-quality criteria at 55% (chronic) and 25% (acute) of the 168 monitoring locations in northern metropolitan areas from November to April. Only 16% (chronic) and 1% (acute) of sites exceeded criteria from May to October. At southern sites, very few samples exceeded chronic water-quality criteria, and no samples exceeded acute criteria. PMID:20806974

A fresh look at road salt: Aquatic toxicity and water-quality impacts on local, regional, and national scales

USGS Publications Warehouse

Corsi, S.R.; Graczyk, D.J.; Geis, S.W.; Booth, N.L.; Richards, K.D.

2010-01-01

A new perspective on the severity of aquatic toxicity impact of road salt was gained by a focused research effort directed at winter runoff periods. Dramatic impacts were observed on local, regional, and national scales. Locally, samples from 7 of 13 Milwaukee, Wisconsin area streams exhibited toxicity in Ceriodaphnia dubia and Pimephales promelas bioassays during road-salt runoff. Another Milwaukee stream was sampled from 1996 to 2008 with 72% of 37 samples exhibiting toxicity in chronic bioassays and 43% in acute bioassays. The maximum chloride concentration was 7730 mg/L. Regionally, in southeast Wisconsin, continuous specific conductance was monitored as a chloride surrogate in 11 watersheds with urban land use from 6.0 to 100%. Elevated specific conductance was observed between November and April at all sites, with continuing effects between May and October at sites with the highest specific conductance. Specific conductance was measured as high as 30 800 ??S/cm (Cl = 11 200 mg/L). Chloride concentrations exceeded U.S. Environmental Protection Agency (USEPA) acute (860 mg/L) and chronic (230 mg/L) water-quality criteria at 55 and 100% of monitored sites, respectively. Nationally, U.S. Geological Survey historical data were examined for 13 northern and 4 southern metropolitan areas. Chloride concentrations exceeded USEPA water-quality criteria at 55% (chronic) and 25% (acute) of the 168 monitoring locations in northern metropolitan areas from November to April. Only 16% (chronic) and 1% (acute) of sites exceeded criteria from May to October. At southern sites, very few samples exceeded chronic water-quality criteria, and no samples exceeded acute criteria. ?? 2010 American Chemical Society.

Light - Instead of UV Protection: New Requirements for Skin Cancer Prevention.

PubMed

Zastrow, Leonhard; Lademann, Jürgen

2016-03-01

The requirements on sunscreens have essentially changed, since some years ago it was demonstrated that approximately 50% of free radicals, that are formed in the skin by solar radiation, originate from the visible and infrared regions of the solar spectrum. In addition, a critical radical concentration threshold could be found. If this concentration, the free radical threshold value (FRTV), is exceeded, sunburn, immunosuppression and skin cancer may develop. Application of sunscreens and lotions protects against sunburn in the UV region of the solar spectrum and therefore is frequently used to extend people's stay in the sun. However, this behaviour can enhance the concentration of free radicals formed in the visible and infrared regions of the solar spectrum, so that the critical radical threshold is exceeded and the skin may be damaged. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Time threshold for second positive phototropism is decreased by a preirradiation with red light.

PubMed Central

Janoudi A-K; Konjevic, R; Apel, P; Poff, K L

1992-01-01

A second positive phototropic response is exhibited by a plant after the time of irradiation has exceeded a time threshold. The time threshold of dark-grown seedlings is about 15 minutes for Arabidopsis thaliana. This threshold is decreased to about 4 minutes by a 669-nanometer preirradiation. Tobacco (Nicotiana tabacum) seedlings show a similar response. The time threshold of dark-grown seedlings is about 60 minutes for tobacco, and is decreased to about 15 minutes after a preirradiation with either 450- or 669- nanometer light. The existence of a time threshold for second positive phototropism and the dependence of this threshold on the irradiation history of the seedling contribute to the complexity of the fluence response relationship for phototropism. PMID:11537887

Time threshold for second positive phototropism is decreased by a preirradiation with red light

NASA Technical Reports Server (NTRS)

Konjevic, R.; Apel, P.; Poff, K. L.

1992-01-01

A second positive phototropic response is exhibited by a plant after the time of irradiation has exceeded a time threshold. The time threshold of dark-grown seedlings is about 15 minutes for Arabidopsis thaliana. This threshold is decreased to about 4 minutes by a 669-nanometer preirradiation. Tobacco (Nicotiana tabacum) seedlings show a similar response. The time threshold of dark-grown seedlings is about 60 minutes for tobacco, and is decreased to about 15 minutes after a preirradiation with either 450- or 669- nanometer light. The existence of a time threshold for second positive phototropism and the dependence of this threshold on the irradiation history of the seedling contribute to the complexity of the fluence response relationship for phototropism.

[The analysis of threshold effect using Empower Stats software].

PubMed

Lin, Lin; Chen, Chang-zhong; Yu, Xiao-dan

2013-11-01

In many studies about biomedical research factors influence on the outcome variable, it has no influence or has a positive effect within a certain range. Exceeding a certain threshold value, the size of the effect and/or orientation will change, which called threshold effect. Whether there are threshold effects in the analysis of factors (x) on the outcome variable (y), it can be observed through a smooth curve fitting to see whether there is a piecewise linear relationship. And then using segmented regression model, LRT test and Bootstrap resampling method to analyze the threshold effect. Empower Stats software developed by American X & Y Solutions Inc has a threshold effect analysis module. You can input the threshold value at a given threshold segmentation simulated data. You may not input the threshold, but determined the optimal threshold analog data by the software automatically, and calculated the threshold confidence intervals.

Thresholds of sea-level rise rate and sea-level acceleration rate in a vulnerable coastal wetland

NASA Astrophysics Data System (ADS)

Wu, W.; Biber, P.; Bethel, M.

2017-12-01

Feedback among inundation, sediment trapping, and vegetation productivity help maintain coastal wetlands facing sea-level rise (SLR). However, when the SLR rate exceeds a threshold, coastal wetlands can collapse. Understanding the threshold help address the key challenge in ecology - nonlinear response of ecosystems to environmental change, and promote communication between ecologists and policy makers. We studied the threshold of SLR rate and developed a new threshold of SLR acceleration rate on sustainability of coastal wetlands as SLR is likely to accelerate due to the enhanced anthropogenic forces. We developed a mechanistic model to simulate wetland change and derived the SLR thresholds for Grand Bay, MS, a micro-tidal estuary with limited upland freshwater and sediment input in the northern Gulf of Mexico. The new SLR acceleration rate threshold complements the threshold of SLR rate and can help explain the temporal lag before the rapid decline of wetland area becomes evident after the SLR rate threshold is exceeded. Deriving these two thresholds depends on the temporal scale, the interaction of SLR with other environmental factors, and landscape metrics, which have not been fully accounted for before this study. The derived SLR rate thresholds range from 7.3 mm/yr to 11.9 mm/yr. The thresholds of SLR acceleration rate are 3.02×10-4 m/yr2 and 9.62×10-5 m/yr2 for 2050 and 2100 respectively. Based on the thresholds developed, predicted SLR that will adversely impact the coastal wetlands in Grand Bay by 2100 will fall within the likely range of SLR under a high warming scenario (RCP8.5), and beyond the very likely range under a low warming scenario (RCP2.6 or 3), highlighting the need to avoid the high warming scenario in the future if these marshes are to be preserved.

48 CFR 2419.804-370 - SBA acceptance under partnership agreements for acquisitions exceeding the simplified acquisition...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false SBA acceptance under partnership agreements for acquisitions exceeding the simplified acquisition threshold. 2419.804-370 Section 2419.804-370 Federal Acquisition Regulations System DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS...

48 CFR 2419.804-370 - SBA acceptance under partnership agreements for acquisitions exceeding the simplified acquisition...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false SBA acceptance under partnership agreements for acquisitions exceeding the simplified acquisition threshold. 2419.804-370 Section 2419.804-370 Federal Acquisition Regulations System DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS...

Reconnaissance of toxic substances in the Jordan River, Salt Lake County, Utah

USGS Publications Warehouse

Thompson, Kendall R.

1984-01-01

A reconnaissance of toxic substances in the Jordan River, Salt Lake County, Utah, was made during July, 1980 to October, 1982 as part of a larger study of the river that included studies of sanitary quality, dissolved oxygen, and turbidity. Samples for toxic substances were collected at five sites on the Jordan River, at three major tributaries, and at six storm drains. The toxic substance that most frequently exceeded State standards was total mercury. About 78 percent of the 138 samples for total mercury exceeded the State standard of 0.05 microgram per liter. Other toxic substances that exceeded State standards were: Ammonia-18 percent of the samples analyzed, cadmium--9 percent, copper-9 percent, zinc--6 percent, and lead--2 percent. One sample for cyanide and one for iron also exceeded State standards. The diversity of toxic substances with concentrations large enough to cause them to be problems increased from the upstream sampling site at the Jordan Narrows to the next two downstream sites at 9000 South and 5800 South Streets. Concentrations of trace elements in stream-bottom materials also increased in a downstream direction. Substantial increases first were observed at 5800 South Street, and they were sustained throughout the downstream study area. Iron is transported in the greatest quantity of all the trace elements studied, with a mean load of 110 pounds per day. Notable loads of barium, boron, lead , and zinc also are transported by the river. DDD, DDE, DDT, dieldrin, heptachlor, methoxychlor, PCB, and 2,4-D were detected in bottom materials; and DDE, Silvex, and 2,4-D were detected in water samples. Of 112 organic compounds in the Environmental Protection Agency 's priority pollutant list, only chloroform was detected in the storm drains that empty into the Joran River. Several metals and phenol also were detected in the samples for priority pollutants. (USGS)

Nonlinear dynamics in ecosystem response to climatic change: case studies and policy implications.

Treesearch

Virginia R. Burkett; Douglas A. Wilcox; Robert Stottlemeyer; Wylie Barrow; Dan Fagre; Jill Baron; Jeff Price; Jennifer L. Nielsen; Craig D. Allen; David L. Peterson; Greg Ruggerone; Thomas Doyle

2005-01-01

Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that...

21 CFR 1313.12 - Requirement of authorization to import.

Code of Federal Regulations, 2012 CFR

2012-04-01

... EXPORTATION OF LIST I AND LIST II CHEMICALS Importation of Listed Chemicals § 1313.12 Requirement of authorization to import. (a) Each regulated person who imports a listed chemical that meets or exceeds the threshold quantities identified in § 1310.04(f) or is a listed chemical for which no threshold has been...

21 CFR 1313.12 - Requirement of authorization to import.

Code of Federal Regulations, 2014 CFR

2014-04-01

... EXPORTATION OF LIST I AND LIST II CHEMICALS Importation of Listed Chemicals § 1313.12 Requirement of authorization to import. (a) Each regulated person who imports a listed chemical that meets or exceeds the threshold quantities identified in § 1310.04(f) or is a listed chemical for which no threshold has been...

21 CFR 1313.12 - Requirement of authorization to import.

Code of Federal Regulations, 2013 CFR

2013-04-01

... EXPORTATION OF LIST I AND LIST II CHEMICALS Importation of Listed Chemicals § 1313.12 Requirement of authorization to import. (a) Each regulated person who imports a listed chemical that meets or exceeds the threshold quantities identified in § 1310.04(f) or is a listed chemical for which no threshold has been...

Pregnancy plasma glucose levels exceeding the American Diabetes Association thresholds, but below the National Diabetes Data Group thresholds for gestational diabetes mellitus, are related to the risk of neonatal macrosomia, hypoglycaemia and hyperbilirubinaemia.

PubMed

Ferrara, A; Weiss, N S; Hedderson, M M; Quesenberry, C P; Selby, J V; Ergas, I J; Peng, T; Escobar, G J; Pettitt, D J; Sacks, D A

2007-02-01

Gestational diabetes mellitus (GDM) is a risk factor for perinatal complications. In several countries, the criteria for the diagnosis of GDM have been in flux, the American Diabetes Association (ADA) thresholds recommended in 2000 being lower than those of the National Diabetes Data Group (NDDG) that have been in use since 1979. We sought to determine the extent to which infants of women meeting only the ADA criteria for GDM are at increased risk of neonatal complications. In a multiethnic cohort of 45,245 women who did not meet the NDDG criteria and were not treated for GDM, we conducted nested case-control studies of three complications of GDM that occurred in their infants: macrosomia (birthweight >4,500 g, n = 494); hypoglycaemia (plasma glucose <2.2 mmo/l, n = 488); and hyperbilirubinaemia (serum bilirubin > or =342 micromol/l (20 mg/dl), n = 578). We compared prenatal glucose levels of the mothers of these infants and mothers of 884 control infants. Women with GDM by ADA criteria only (two or more glucose values exceeding the threshold) had an increased risk of having an infant with macrosomia (odds ratio OR = 3.40, 95% CI = 1.55-7.43), hypoglycaemia (OR = 2.61, 95% CI = 0.99-6.92) or hyperbilirubinaemia (OR = 2.22, 95% CI = 0.98-5.04). Glucose levels 1 h after the 100-g glucose challenge that exceeded the ADA threshold were particularly strongly associated with each complication. These results lend support to the ADA recommendations and highlight the importance of the 1-h glucose measurement in a diagnostic test for GDM.

A prototype system for forecasting landslides in the Seattle, Washington, area

USGS Publications Warehouse

Chleborad, Alan F.; Baum, Rex L.; Godt, Jonathan W.; Powers, Philip S.

2008-01-01

Empirical rainfall thresholds and related information form the basis of a prototype system for forecasting landslides in the Seattle area. The forecasts are tied to four alert levels, and a decision tree guides the use of thresholds to determine the appropriate level. From analysis of historical landslide data, we developed a formula for a cumulative rainfall threshold (CT), P3  =  88.9 − 0.67P15, defined by rainfall amounts in millimeters during consecutive 3 d (72 h) periods, P3, and the 15 d (360 h) period before P3, P15. The variable CT captures more than 90% of historical events of three or more landslides in 1 d and 3 d periods recorded from 1978 to 2003. However, the low probability of landslide occurrence on a day when the CT is exceeded at one or more rain gauges (8.4%) justifies a low-level of alert for possible landslide occurrence, but it does trigger more vigilant monitoring of rainfall and soil wetness. Exceedance of a rainfall intensity-duration threshold I  =  82.73D−1.13, for intensity, I (mm/hr), and duration, D (hr), corresponds to a higher probability of landslide occurrence (30%) and forms the basis for issuing warnings of impending, widespread occurrence of landslides. Information about the area of exceedance and soil wetness can be used to increase the certainty of landslide forecasts (probabilities as great as 71%). Automated analysis of real-time rainfall and subsurface water data and digital quantitative precipitation forecasts are needed to fully implement a warning system based on the two thresholds.

Wildlife toxicity extrapolations: NOAEL versus LOAEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fairbrother, A.; Berg, M. van den

1995-12-31

Ecotoxicological assessments must rely on the extrapolation of toxicity data from a few indicator species to many species of concern. Data are available from laboratory studies (e.g., quail, mallards, rainbow trout, fathead minnow) and some planned or serendipitous field studies of a broader, but by no means comprehensive, suite of species. Yet all ecological risk assessments begin with an estimate of risk based on information gleaned from the literature. One is then confronted with the necessity of extrapolating toxicity information from a limited number of indicator species to all organisms of interest. This is a particularly acute problem when tryingmore » to estimate hazards to wildlife in terrestrial systems as there is an extreme paucity of data for most chemicals in all but a handful of species. This section continues the debate by six panelists of the ``correct`` approach for determining wildlife toxicity thresholds by debating which toxicity value should be used for setting threshold criteria. Should the lowest observable effect level (LOAEL) be used or is it more appropriate to use the no observable effect level (NOAEL)? What are the short-comings of using either of these point estimates? Should a ``benchmark`` approach, similar to that proposed for human health risk assessments, be used instead, where an EC{sub 5} or EC{sub 10} and associated confidence limits are determined and then divided by a safety factor? How should knowledge of the slope of the dose-response curve be incorporated into determination of toxicity threshold values?« less

Evaluation of an operational malaria outbreak identification and response system in Mpumalanga Province, South Africa.

PubMed

Coleman, Marlize; Coleman, Michael; Mabuza, Aaron M; Kok, Gerdalize; Coetzee, Maureen; Durrheim, David N

2008-04-27

To evaluate the performance of a novel malaria outbreak identification system in the epidemic prone rural area of Mpumalanga Province, South Africa, for timely identification of malaria outbreaks and guiding integrated public health responses. Using five years of historical notification data, two binomial thresholds were determined for each primary health care facility in the highest malaria risk area of Mpumalanga province. Whenever the thresholds were exceeded at health facility level (tier 1), primary health care staff notified the malaria control programme, which then confirmed adequate stocks of malaria treatment to manage potential increased cases. The cases were followed up at household level to verify the likely source of infection. The binomial thresholds were reviewed at village/town level (tier 2) to determine whether additional response measures were required. In addition, an automated electronic outbreak identification system at town/village level (tier 2) was integrated into the case notification database (tier 3) to ensure that unexpected increases in case notification were not missed.The performance of these binomial outbreak thresholds was evaluated against other currently recommended thresholds using retrospective data. The acceptability of the system at primary health care level was evaluated through structured interviews with health facility staff. Eighty four percent of health facilities reported outbreaks within 24 hours (n = 95), 92% (n = 104) within 48 hours and 100% (n = 113) within 72 hours. Appropriate response to all malaria outbreaks (n = 113, tier 1, n = 46, tier 2) were achieved within 24 hours. The system was positively viewed by all health facility staff. When compared to other epidemiological systems for a specified 12 month outbreak season (June 2003 to July 2004) the binomial exact thresholds produced one false weekly outbreak, the C-sum 12 weekly outbreaks and the mean + 2 SD nine false weekly outbreaks. Exceeding the binomial level 1 threshold triggered an alert four weeks prior to an outbreak, but exceeding the binomial level 2 threshold identified an outbreak as it occurred. The malaria outbreak surveillance system using binomial thresholds achieved its primary goal of identifying outbreaks early facilitating appropriate local public health responses aimed at averting a possible large-scale epidemic in a low, and unstable, malaria transmission setting.

How might selenium moderate the toxic effects of mercury in stream fish of the Western USA?

EPA Science Inventory

The ability of selenium (Se) to moderate mercury (Hg) toxicity is well established in the literature. Mercury exposures that might otherwise produce toxic effects are counteracted by Se, particularly when Se:Hg molar ratios approach or exceed 1. We analyzed whole body Se and Hg c...

How might selenium moderate the toxic effects of mercury in stream fish of the Western USA? - abstract

EPA Science Inventory

The ability of selenium (Se) to moderate mercury (Hg) toxicity is well established in the literature. Mercury exposures that might otherwise produce toxic effects are counteracted by Se, particularly when Se:Hg molar ratios approach or exceed 1. We analyzed whole body Se and Hg c...

Clinical Value of Basal Serum Progesterone Prior to Initiate Ovarian Hyper-Stimulation with GnRH Antagonists: A Retrospective Cohort Study.

PubMed

Faulisi, Sonia; Reschini, Marco; Borroni, Raffaella; Paffoni, Alessio; Busnelli, Andrea; Somigliana, Edgardo

2017-01-01

The routine assessment of day 3 serum progesterone prior to initiation of ovarian hyper-stimulation with the use of GnRH antagonists is under debate. In this study, we evaluated the clinical utility of this policy. Retrospective cohort study of women undergoing in vitro fertilization (IVF) with the use of GnRH antagonists aimed at determining the frequency of cases with progesterone levels exceeding the recommended threshold of 1,660 pg/ml and at evaluating whether this assessment may be predictive of pregnancy. Serum progesterone exceeded the recommended threshold in one case (0.3%, 95% CI 0.01-1.5). The median (interquartile range) basal progesterone in women who did (n = 95) and did not (n = 217) become pregnant were 351 (234-476) and 380 (237-531) pg/ml, respectively (p = 0.28). The 90th percentile of the basal progesterone distribution in women who became pregnant was 660 pg/ml. Cases with serum progesterone exceeding this threshold in successful and unsuccessful cycles were 10 (10%) and 30 (14%), respectively (p = 0.47). The capacity of basal progesterone to predict pregnancy was evaluated using receiver operating characteristic curve (area under the curve = 0.54, 95% CI 0.47-0.61, p = 0.28). No graphically evident threshold emerged. Routine day 3 serum progesterone assessment in IVF cycles with the use of GnRH antagonists is not justified. Further evidence is warranted prior to claiming its systematic use. © 2016 S. Karger AG, Basel.

Physical activity levels of normal-weight and overweight girls and boys during primary school recess.

PubMed

Stratton, Gareth; Ridgers, Nicola D; Fairclough, Stuart J; Richardson, David J

2007-06-01

This study aimed to compare moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) in normal-weight and overweight boys and girls during school recess. Four hundred twenty children, age 6 to 10 years, were randomly selected from 25 schools in England. Three hundred seventy-seven children completed the study. BMI was calculated from height and weight measurements, and heart rate reserve thresholds of 50% and 75% reflected children's engagement in MVPA and VPA, respectively. There was a significant main effect for sex and a significant interaction between BMI category and sex for the percent of recess time spent in MVPA and VPA. Normal-weight girls were the least active group, compared with overweight boys and girls who were equally active. Fifty-one boys and 24 girls of normal weight achieved the 40% threshold; of these, 30 boys and 10 girls exceeded 50% of recess time in MVPA. Eighteen overweight boys and 22 overweight girls exceeded the 40% threshold, whereas 8 boys and 8 girls exceeded the 50% threshold. Overweight boys were significantly less active than their normal-weight male counterparts; this difference did not hold true for girls. Even though nearly double the number of normal-weight children achieved the 40% of MVPA during recess compared with overweight children, physical activity promotion in school playgrounds needs to be targeted not only at overweight but at other health parameters, as 40 overweight children met the 40% MVPA target proposed for recess.

Optimal thresholds for the estimation of area rain-rate moments by the threshold method

NASA Technical Reports Server (NTRS)

Short, David A.; Shimizu, Kunio; Kedem, Benjamin

1993-01-01

Optimization of the threshold method, achieved by determination of the threshold that maximizes the correlation between an area-average rain-rate moment and the area coverage of rain rates exceeding the threshold, is demonstrated empirically and theoretically. Empirical results for a sequence of GATE radar snapshots show optimal thresholds of 5 and 27 mm/h for the first and second moments, respectively. Theoretical optimization of the threshold method by the maximum-likelihood approach of Kedem and Pavlopoulos (1991) predicts optimal thresholds near 5 and 26 mm/h for lognormally distributed rain rates with GATE-like parameters. The agreement between theory and observations suggests that the optimal threshold can be understood as arising due to sampling variations, from snapshot to snapshot, of a parent rain-rate distribution. Optimal thresholds for gamma and inverse Gaussian distributions are also derived and compared.

The influence of uncertainty and location-specific conditions on the environmental prioritisation of human pharmaceuticals in Europe.

PubMed

Oldenkamp, Rik; Huijbregts, Mark A J; Ragas, Ad M J

2016-05-01

The selection of priority APIs (Active Pharmaceutical Ingredients) can benefit from a spatially explicit approach, since an API might exceed the threshold of environmental concern in one location, while staying below that same threshold in another. However, such a spatially explicit approach is relatively data intensive and subject to parameter uncertainty due to limited data. This raises the question to what extent a spatially explicit approach for the environmental prioritisation of APIs remains worthwhile when accounting for uncertainty in parameter settings. We show here that the inclusion of spatially explicit information enables a more efficient environmental prioritisation of APIs in Europe, compared with a non-spatial EU-wide approach, also under uncertain conditions. In a case study with nine antibiotics, uncertainty distributions of the PAF (Potentially Affected Fraction) of aquatic species were calculated in 100∗100km(2) environmental grid cells throughout Europe, and used for the selection of priority APIs. Two APIs have median PAF values that exceed a threshold PAF of 1% in at least one environmental grid cell in Europe, i.e., oxytetracycline and erythromycin. At a tenfold lower threshold PAF (i.e., 0.1%), two additional APIs would be selected, i.e., cefuroxime and ciprofloxacin. However, in 94% of the environmental grid cells in Europe, no APIs exceed either of the thresholds. This illustrates the advantage of following a location-specific approach in the prioritisation of APIs. This added value remains when accounting for uncertainty in parameter settings, i.e., if the 95th percentile of the PAF instead of its median value is compared with the threshold. In 96% of the environmental grid cells, the location-specific approach still enables a reduction of the selection of priority APIs of at least 50%, compared with a EU-wide prioritisation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Creep and fracture of dispersion-strengthened materials

NASA Technical Reports Server (NTRS)

Raj, Sai V.

1991-01-01

The creep and fracture of dispersion strengthened materials is reviewed. A compilation of creep data on several alloys showed that the reported values of the stress exponent for creep varied between 3.5 and 100. The activation energy for creep exceeded that for lattice self diffusion in the matrix in the case of some materials and a threshold stress behavior was generally reported in these instances. The threshold stress is shown to be dependent on the interparticle spacing and it is significantly affected by the initial microstructure. The effect of particle size and the nature of the dispersoid on the threshold stress is not well understood at the present time. In general, most studies indicate that the microstructure after creep is similar to that before testing and very few dislocations are usually observed. It is shown that the stress acting on a dispersoid due to a rapidly moving dislocation can exceed the particle yield strength of the G sub p/1000, where G sub p is the shear modulus of the dispersoid. The case when the particle deforms is examined and it is suggested that the dislocation creep threshold stress of the alloy is equal to the yield strength of the dispersoid under these conditions. These results indicate that the possibility that the dispersoid creep threshold stress is determined by either the particle yield strength or the stress required to detach a dislocation from the dispersoid matrix interface. The conditions under which the threshold stress is influenced by one or the other mechanism are discussed and it is shown that the particle yield strength is important until the extent of dislocation core relaxation at the dispersoid matrix interface exceeds about 25 pct. depending on the nature of the particle matrix combination. Finally, the effect of grain boundaries and grain morphology on the creep and fracture behavior of dispersoid strengthened alloys is examined.

Precipitation thresholds for landslide occurrence near Seattle, Mukilteo, and Everett, Washington

USGS Publications Warehouse

Scheevel, Caroline R.; Baum, Rex L.; Mirus, Benjamin B.; Smith, Joel B.

2017-04-27

Shallow landslides along coastal bluffs frequently occur in the railway corridor between Seattle and Everett, Washington. These slides disrupt passenger rail service, both because of required track maintenance and because the railroad owner, Burlington Northern Santa Fe Railway, does not allow passenger travel for 48 hours after a disruptive landslide. Sound Transit, which operates commuter trains in the corridor, is interested in a decision-making tool to help preemptively cancel passenger railway service in dangerous conditions and reallocate resources to alternative transportation.Statistical analysis showed that a majority of landslides along the Seattle-Everett Corridor are strongly correlated with antecedent rainfall, but that 21-37 percent of recorded landslide dates experienced less than 1 inch of precipitation in the 3 days preceding the landslide and less than 4 inches of rain in the 15 days prior to the preceding 3 days. We developed two empirical thresholds to identify precipitation conditions correlated with landslide occurrence. The two thresholds are defined as P3 = 2.16-0.44P15 and P3 = 2.16-0.22P32, where P3 is the cumulative precipitation in the 3 days prior to the considered date and P15 or P32 is the cumulative precipitation in the 15 days or 32 days prior to P3 (all measurements given in inches). The two thresholds, when compared to a previously developed threshold, quantitatively improve the prediction rate.We also investigated rainfall intensity-duration (ID) thresholds to determine whether revision would improve identification of moderate-intensity, landslide-producing storms. New, optimized ID thresholds evaluate rainstorms lasting at least 12 hours and identify landslide-inducing storms that were typically missed by previously published ID thresholds. The main advantage of the ID thresholds appears when they are combined with recent-antecedent thresholds because rainfall conditions that exceed both threshold types are more likely to induce two or more landslides than conditions that exceed only one threshold type.

Cost-Effectiveness Analysis of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Preoperative Treatment of Extremity Soft Tissue Sarcomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard, Patrick, E-mail: patrjr@uw.edu; Phillips, Mark; Smith, Wade

Purpose: Create a cost-effectiveness model comparing preoperative intensity modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3DCRT) for extremity soft tissue sarcomas. Methods and Materials: Input parameters included 5-year local recurrence rates, rates of acute wound adverse events, and chronic toxicities (edema, fracture, joint stiffness, and fibrosis). Health-state utilities were used to calculate quality-adjusted life years (QALYs). Overall treatment costs per QALY or incremental cost-effectiveness ratio (ICER) were calculated. Roll-back analysis was performed using average costs and utilities to determine the baseline preferred radiation technique. One-way, 2-way, and probabilistic sensitivity analyses (PSA) were performed for input parameters with themore » largest impact on the ICER. Results: Overall treatment costs were $17,515.58 for 3DCRT compared with $22,920.51 for IMRT. The effectiveness was higher for IMRT (3.68 QALYs) than for 3DCRT (3.35 QALYs). The baseline ICER for IMRT was $16,842.75/QALY, making it the preferable treatment. The ICER was most sensitive to the probability of local recurrence, upfront radiation costs, local recurrence costs, certain utilities (no toxicity/no recurrence, grade 1 toxicity/no local recurrence, grade 4 toxicity/no local recurrence), and life expectancy. Dominance patterns emerged when the cost of 3DCRT exceeded $15,532.05 (IMRT dominates) or the life expectancy was under 1.68 years (3DCRT dominates). Furthermore, preference patterns changed based on the rate of local recurrence (threshold: 13%). The PSA results demonstrated that IMRT was the preferred cost-effective technique for 64% of trials compared with 36% for 3DCRT. Conclusions: Based on our model, IMRT is the preferred technique by lowering rates of local recurrence, severe toxicities, and improving QALYs. From a third-party payer perspective, IMRT should be a supported approach for extremity soft tissue sarcomas.« less

PRESERVATIVE LEACHING FROM WEATHERED CCA-TREATED WOOD

EPA Science Inventory

Disposal of discarded CCA-treated wood in landfills raises concerns with respect to leaching of preservative compounds. When unweathered CCA-treated wood is leached using the toxicity characteristic leaching procedure (TCLP), arsenic concentrations exceed the toxicity characteris...

Aquatic toxicity of airfield-pavement deicer materials and implications for airport runoff.

PubMed

Corsi, Steven R; Geis, Steven W; Bowman, George; Failey, Greg G; Rutter, Troy D

2009-01-01

Concentrations of airfield-pavement deicer materials (PDM) in a study of airport runoff often exceeded levels of concern regarding aquatic toxicity. Toxicity tests on Vibrio fischeri, Pimephales promelas, Ceriodaphnia dubia, and Pseudokirchneriella subcapitata (commonly known as Selenastrum capricornutum) were performed with potassium acetate (K-Ac) PDM, sodium formate (Na-For) PDM, and with freezing-point depressants (K-Ac and Na-For). Results indicate that toxicity in PDM is driven by the freezing-point depressants in all tests except the Vibrio fisheri test for Na-For PDM which is influenced by an additive. Acute toxicity end points for different organisms ranged from 298 to 6560 mg/L (as acetate) for K-Ac PDM and from 1780 to 4130 mg/L (as formate) for Na-For PDM. Chronic toxicity end points ranged from 19.9 to 336 mg/L (as acetate) for K-Ac PDM and from 584 to 1670 mg/L (as formate) for Na-For PDM. Sample results from outfalls at General Mitchell International Airport in Milwaukee, WI (GMIA) indicated that 40% of samples had concentrations greater thanthe aquatic-life benchmarkfor K-Ac PDM. K-Ac has replaced urea during the 1990s as the most widely used PDM at GMIA and in the United States. Results of ammonia samples from airport outfalls during periods when urea-based PDM was used at GMIA indicated that 41% of samples had concentrations exceeding the U.S. Environmental Protection Agency (USEPA) 1-h water-quality criterion. The USEPA 1-h water-quality criterion for chloride was exceeded in 68% of samples collected in the receiving stream, a result of road-salt runoff from urban influence near the airport. Results demonstrate that PDM must be considered to comprehensively evaluate the impact of chemical deicers on aquatic toxicity in water containing airport runoff.

Low level lead exposure: history and discovery.

PubMed

Needleman, Herbert

2009-04-01

The history of lead toxicity spans 2 millennnia. With increasingly sensitive methods, deficits due to lead exposure have been demonstrated at lower and lower doses. Persuasive evidence suggests that no threshold for lead toxicity exists.

An objective method and measuring equipment for noise control and acoustic diagnostics of motorcars. [acoustic diagnostics on automobile engines

NASA Technical Reports Server (NTRS)

Kacprowski, J.; Motylewski, J.; Miazga, J.

1974-01-01

An objective method and apparatus for noise control and acoustic diagnostics of motorcar engines are reported. The method and apparatus let us know whether the noisiness of the vehicle under test exceeds the admissible threshold levels given by appropriate standards and if so what is the main source of the excessive noise. The method consists in measuring both the overall noise level and the sound pressure levels in definite frequency bands while the engine speed is controlled as well and may be fixed at prescribed values. Whenever the individually adjusted threshold level has been exceeded in any frequency band, a self-sustaining control signal is sent.

Centrifugal unbalance detection system

DOEpatents

Cordaro, Joseph V.; Reeves, George; Mets, Michael

2002-01-01

A system consisting of an accelerometer sensor attached to a centrifuge enclosure for sensing vibrations and outputting a signal in the form of a sine wave with an amplitude and frequency that is passed through a pre-amp to convert it to a voltage signal, a low pass filter for removing extraneous noise, an A/D converter and a processor and algorithm for operating on the signal, whereby the algorithm interprets the amplitude and frequency associated with the signal and once an amplitude threshold has been exceeded the algorithm begins to count cycles during a predetermined time period and if a given number of complete cycles exceeds the frequency threshold during the predetermined time period, the system shuts down the centrifuge.

Ionizing radiation exposure as a result of diagnostic imaging in patients with lymphoma.

PubMed

Crowley, M P; O'Neill, S B; Kevane, B; O'Neill, D C; Eustace, J A; Cahill, M R; Bird, B; Maher, M M; O'Regan, K; O'Shea, D

2016-05-01

Survival rates among patients with lymphoma continue to improve. Strategies aimed at reducing potential treatment-related toxicity are increasingly prioritized. While radiological procedures play an important role, ionizing radiation exposure has been linked to an increased risk of malignancy, particularly among individuals whose cumulative radiation exposure exceeds a specific threshold (75 millisieverts). Within this retrospective study, the cumulative radiation exposure dose was quantified for 486 consecutive patients with lymphoma. The median estimated total cumulative effective dose (CED) of ionizing radiation per subject was 69 mSv (42-118). However, younger patients (under 40 years) had a median CED of 89 mSv (55-124). This study highlights the considerable radiation exposure occurring among patients with lymphoma as a result of diagnostic imaging. To limit the risk of secondary carcinogenesis, consideration should be given to monitoring cumulative radiation exposure in individual patients as well as considering imaging modalities, which do not impart an ionizing radiation dose.

Cyanobacteria and cyanotoxins at the river-estuarine transition.

PubMed

Bukaveckas, Paul A; Franklin, Rima; Tassone, Spencer; Trache, Brendan; Egerton, Todd

2018-06-01

We examined seasonal and longitudinal patterns in the occurrence of toxic cyanobacteria in the James River Estuary (Virginia). Highest chlorophyll and cyanobacteria levels were observed in the tidal freshwater segment, particularly during dry summers when freshwater replacement time was long. Cyanobacteria accounted for a small proportion of phytoplankton biomass (7-15%), and Microcystis comprised a small proportion of the cyanobacteria (<1%). Despite this, measureable levels of microcystin were commonly observed in water (>85% of samples in July, August and September), fish tissues (87% of planktivorous fishes) and shellfish (83% of individuals). Generic indicators of algal blooms (chlorophyll and algal biomass) had limited utility for predicting microcystin concentrations. However, chlorophyll was found to be a useful predictor for the probability of exceeding specific toxin thresholds. Tissue microcystin concentrations were highest in fish and shellfish collected from the tidal fresh segment, but were detectable in biota collected from the oligohaline at distances 50 km seaward. Copyright © 2018 Elsevier B.V. All rights reserved.

48 CFR 52.213-4 - Terms and Conditions-Simplified Acquisitions (Other Than Commercial Items)

Code of Federal Regulations, 2010 CFR

2010-10-01

...-consuming products listed in the ENERGY STAR® Program or Federal Energy Management Program (FEMP) will be... exceeds the micro-purchase threshold and the acquisition— (A) Is set aside for small business concerns; or (B) Cannot be set aside for small business concerns (see 19.502-2), and does not exceed $25,000.) (x...

Systematic review and meta-analysis of the performance of clinical risk assessment instruments for screening for osteoporosis or low bone density

PubMed Central

Edwards, D. L.; Saleh, A. A.; Greenspan, S. L.

2015-01-01

Summary We performed a systematic review and meta-analysis of the performance of clinical risk assessment instruments for screening for DXA-determined osteoporosis or low bone density. Commonly evaluated risk instruments showed high sensitivity approaching or exceeding 90 % at particular thresholds within various populations but low specificity at thresholds required for high sensitivity. Simpler instruments, such as OST, generally performed as well as or better than more complex instruments. Introduction The purpose of the study is to systematically review the performance of clinical risk assessment instruments for screening for dual-energy X-ray absorptiometry (DXA)-determined osteoporosis or low bone density. Methods Systematic review and meta-analysis were performed. Multiple literature sources were searched, and data extracted and analyzed from included references. Results One hundred eight references met inclusion criteria. Studies assessed many instruments in 34 countries, most commonly the Osteoporosis Self-Assessment Tool (OST), the Simple Calculated Osteoporosis Risk Estimation (SCORE) instrument, the Osteoporosis Self-Assessment Tool for Asians (OSTA), the Osteoporosis Risk Assessment Instrument (ORAI), and body weight criteria. Meta-analyses of studies evaluating OST using a cutoff threshold of <1 to identify US postmenopausal women with osteoporosis at the femoral neck provided summary sensitivity and specificity estimates of 89 % (95%CI 82–96 %) and 41 % (95%CI 23–59 %), respectively. Meta-analyses of studies evaluating OST using a cutoff threshold of 3 to identify US men with osteoporosis at the femoral neck, total hip, or lumbar spine provided summary sensitivity and specificity estimates of 88 % (95%CI 79–97 %) and 55 % (95%CI 42–68 %), respectively. Frequently evaluated instruments each had thresholds and populations for which sensitivity for osteoporosis or low bone mass detection approached or exceeded 90 % but always with a trade-off of relatively low specificity. Conclusions Commonly evaluated clinical risk assessment instruments each showed high sensitivity approaching or exceeding 90 % for identifying individuals with DXA-determined osteoporosis or low BMD at certain thresholds in different populations but low specificity at thresholds required for high sensitivity. Simpler instruments, such as OST, generally performed as well as or better than more complex instruments. PMID:25644147

A Multistrain Mathematical Model To Investigate the Role of Pyrazinamide in the Emergence of Extensively Drug-Resistant Tuberculosis

PubMed Central

Shrestha, Sourya; Knight, Gwenan M.; Cohen, Ted; White, Richard G.; Cobelens, Frank

2016-01-01

ABSTRACT Several infectious diseases of global importance—e.g., HIV infection and tuberculosis (TB)—require prolonged treatment with combination antimicrobial regimens typically involving high-potency core agents coupled with additional companion drugs that protect against the de novo emergence of mutations conferring resistance to the core agents. Often, the most effective (or least toxic) companion agents are reused in sequential (first-line, second-line, etc.) regimens. We used a multistrain model of Mycobacterium tuberculosis transmission in Southeast Asia to investigate how this practice might facilitate the emergence of extensive drug resistance, i.e., resistance to multiple core agents. We calibrated this model to regional TB and drug resistance data using an approximate Bayesian computational approach. We report the proportion of data-consistent simulations in which the prevalence of pre-extensively drug-resistant (pre-XDR) TB—defined as resistance to both first-line and second-line core agents (rifampin and fluoroquinolones)—exceeds predefined acceptability thresholds (1 to 2 cases per 100,000 population by 2035). The use of pyrazinamide (the most effective companion agent) in both first-line and second-line regimens increased the proportion of simulations in which the prevalence exceeded the pre-XDR acceptability threshold by 7-fold compared to a scenario in which patients with pyrazinamide-resistant TB received an alternative drug. Model parameters related to the emergence and transmission of pyrazinamide-resistant TB and resistance amplification were among those that were the most strongly correlated with the projected pre-XDR prevalence, indicating that pyrazinamide resistance acquired during first-line treatment subsequently promotes amplification to pre-XDR TB under pyrazinamide-containing second-line treatment. These findings suggest that the appropriate use of companion drugs may be critical to preventing the emergence of strains resistant to multiple core agents. PMID:27956422

Environmental Exposure to Arsenic, Lead, and Cadmium in People Living near Janghang Copper Smelter in Korea.

PubMed

Kim, Yong-Dae; Eom, Sang-Yong; Yim, Dong-Hyuk; Kim, In-Soo; Won, Hee-Kwan; Park, Choong-Hee; Kim, Guen-Bae; Yu, Seung-Do; Choi, Byung-Sun; Park, Jung-Duck; Kim, Heon

2016-04-01

Concentrations of heavy metals exceed safety thresholds in the soil near Janghang Copper Refinery, a smelter in Korea that operated from 1936 to 1989. This study was conducted to evaluate the level of exposure to toxic metals and the potential effect on health in people living near the smelter. The study included 572 adults living within 4 km of the smelter and compared them with 413 controls group of people living similar lifestyles in a rural area approximately 15 km from the smelter. Urinary arsenic (As) level did not decrease according to the distance from the smelter, regardless of gender and working history in smelters and mines. However, in subjects who had no occupational exposure to toxic metals, blood lead (Pb) and cadmium (Cd) and urinary Cd decreased according to the distance from the smelter, both in men and women. Additionally, the distance from the smelter was a determinant factor for a decrease of As, Pb, and Cd in multiple regression models, respectively. On the other hands, urinary Cd was a risk factor for renal tubular dysfunction in populations living near the smelter. These results suggest that Janghang copper smelter was a main contamination source of As, Pb, and Cd, and populations living near the smelter suffered some adverse health effects as a consequence. The local population should be advised to make efforts to reduce exposure to environmental contaminants, in order to minimize potential health effects, and to pay close attention to any health problems possibly related to toxic metal exposure.

Deepwater Horizon crude oil impacts the developing hearts of large predatory pelagic fish

PubMed Central

Incardona, John P.; Gardner, Luke D.; Linbo, Tiffany L.; Brown, Tanya L.; Esbaugh, Andrew J.; Mager, Edward M.; Stieglitz, John D.; French, Barbara L.; Labenia, Jana S.; Laetz, Cathy A.; Tagal, Mark; Sloan, Catherine A.; Elizur, Abigail; Benetti, Daniel D.; Grosell, Martin; Block, Barbara A.; Scholz, Nathaniel L.

2014-01-01

The Deepwater Horizon disaster released more than 636 million L of crude oil into the northern Gulf of Mexico. The spill oiled upper surface water spawning habitats for many commercially and ecologically important pelagic fish species. Consequently, the developing spawn (embryos and larvae) of tunas, swordfish, and other large predators were potentially exposed to crude oil-derived polycyclic aromatic hydrocarbons (PAHs). Fish embryos are generally very sensitive to PAH-induced cardiotoxicity, and adverse changes in heart physiology and morphology can cause both acute and delayed mortality. Cardiac function is particularly important for fast-swimming pelagic predators with high aerobic demand. Offspring for these species develop rapidly at relatively high temperatures, and their vulnerability to crude oil toxicity is unknown. We assessed the impacts of field-collected Deepwater Horizon (MC252) oil samples on embryos of three pelagic fish: bluefin tuna, yellowfin tuna, and an amberjack. We show that environmentally realistic exposures (1–15 µg/L total PAH) cause specific dose-dependent defects in cardiac function in all three species, with circulatory disruption culminating in pericardial edema and other secondary malformations. Each species displayed an irregular atrial arrhythmia following oil exposure, indicating a highly conserved response to oil toxicity. A considerable portion of Gulf water samples collected during the spill had PAH concentrations exceeding toxicity thresholds observed here, indicating the potential for losses of pelagic fish larvae. Vulnerability assessments in other ocean habitats, including the Arctic, should focus on the developing heart of resident fish species as an exceptionally sensitive and consistent indicator of crude oil impacts. PMID:24706825

A Multinomial Model for Identifying Significant Pure-Tone Threshold Shifts

ERIC Educational Resources Information Center

Schlauch, Robert S.; Carney, Edward

2007-01-01

Purpose: Significant threshold differences on retest for pure-tone audiometry are often evaluated by application of ad hoc rules, such as a shift in a pure-tone average or in 2 adjacent frequencies that exceeds a predefined amount. Rules that are so derived do not consider the probability of observing a particular audiogram. Methods: A general…

75 FR 42835 - Medicare Program; Inpatient Rehabilitation Facility Prospective Payment System for Federal Fiscal...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-22

... estimated cost of the case exceeds the adjusted outlier threshold. We calculate the adjusted outlier... to 80 percent of the difference between the estimated cost of the case and the outlier threshold. In... Federal Prospective Payment Rates VI. Update to Payments for High-Cost Outliers under the IRF PPS A...

76 FR 64983 - Self-Regulatory Organizations; NYSE Amex LLC; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-19

...-Regulatory Organizations; NYSE Amex LLC; Notice of Filing and Immediate Effectiveness of Proposed Rule Change... currently count toward both the $350,000 cap and the 3,500,000 thresholds, but are not themselves capped... standard fee schedule, with the exception of transactions that exceed the fee cap threshold for Specialists...

Using Stream Classification to Prioritize Riparian Rehabilitation After Extreme Events

Treesearch

Sherman Swanson

1989-01-01

Historic use of many stream riparian areas and associated watersheds has impaired the capacity of riparian vegetation and floodplains to reduce stream energy and trap sediments. As low-gradient streams with erodible banks increase in width and change their pattern, they approach a threshold of instability. Once a stream exceeds a threshold, it must proceed through a...

Contact toxicity of 40 insecticides tested on pandora moth larvae

Treesearch

Robert L. Lyon

1971-01-01

Forty insecticides and an antifeeding compound were tested on pandora moth larvae (Coloradia pandora Blake) in the second and third instars. A total of 21 insecticides were more toxic at LD90 than DDT, providing a good choice of candidates for field testing. Ten exceeded DDT in toxicity tenfold or more. These were, in...

Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA.

PubMed

Walters, David M; Rosi-Marshall, Emma; Kennedy, Theodore A; Cross, Wyatt F; Baxter, Colden V

2015-10-01

Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17-1.59 μg g(-1) Hg and 1.35-2.65 μg g(-1) Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ(15) N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6-100% and 56-100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. © 2015 SETAC.

Cost-effectiveness of cetuximab and panitumumab for chemotherapy-refractory metastatic colorectal cancer.

PubMed

Carvalho, Adriana Camargo; Leal, Frederico; Sasse, Andre Deeke

2017-01-01

Cetuximab and panitumumab are monoclonal antibodies targeting the epidermal growth factor receptor. Both drugs are active against RAS wild type metastatic colorectal cancer after chemotherapy failure, with similar efficacy and toxicity profiles. However, their cost and limited survival benefits may compromise incorporation in the Brazilian public healthcare system, the Unified Heath System (Sistema Único de Saúde) (SUS). A cost-effectiveness analysis was conducted using a Markov model from the Brazilian Public health perspective and a lifetime horizon in patients with RAS -wt mCRC. Transition probabilities and mortality rates were extracted from randomized studies. Treatment costs were obtained from price tables regulated by the Brazilian Health Ministry. The World Health Organization recommendation of three times GDP per capita was used to define the cost-effectiveness threshold. The use of cetuximab or panitumumab for chemotherapy-refractory mCRC patients resulted in 0.22 additional life-years relative to BSC, with incremental cost-effectiveness ratios (ICERs) of $58,240 and $52,772 per LY, respectively. That exceeds the pre-specified threshold for cost-effectiveness. Acquisition of biological agents was the major driver of increased costs. Our economic evaluation demonstrates that both cetuximab and panitumumab are not a cost-effective approach in RAS-wt mCRC patients. Discussion about drug price should be prioritized to enable incorporation of these monoclonal antibodies in the SUS.

Diethylene glycol-induced toxicities show marked threshold dose response in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landry, Greg M., E-mail: Landry.Greg@mayo.edu; Dunning, Cody L., E-mail: cdunni@lsuhsc.edu; Abreo, Fleurette, E-mail: fabreo@lsuhsc.edu

Diethylene glycol (DEG) exposure poses risks to human health because of widespread industrial use and accidental exposures from contaminated products. To enhance the understanding of the mechanistic role of metabolites in DEG toxicity, this study used a dose response paradigm to determine a rat model that would best mimic DEG exposure in humans. Wistar and Fischer-344 (F-344) rats were treated by oral gavage with 0, 2, 5, or 10 g/kg DEG and blood, kidney and liver tissues were collected at 48 h. Both rat strains treated with 10 g/kg DEG had equivalent degrees of metabolic acidosis, renal toxicity (increased BUNmore » and creatinine and cortical necrosis) and liver toxicity (increased serum enzyme levels, centrilobular necrosis and severe glycogen depletion). There was no liver or kidney toxicity at the lower DEG doses (2 and 5 g/kg) regardless of strain, demonstrating a steep threshold dose response. Kidney diglycolic acid (DGA), the presumed nephrotoxic metabolite of DEG, was markedly elevated in both rat strains administered 10 g/kg DEG, but no DGA was present at 2 or 5 g/kg, asserting its necessary role in DEG-induced toxicity. These results indicate that mechanistically in order to produce toxicity, metabolism to and significant target organ accumulation of DGA are required and that both strains would be useful for DEG risk assessments. - Highlights: • DEG produces a steep threshold dose response for kidney injury in rats. • Wistar and F-344 rats do not differ in response to DEG-induced renal injury. • The dose response for renal injury closely mirrors that for renal DGA accumulation. • Results demonstrate the importance of DGA accumulation in producing kidney injury.« less

Magnetoencephalography with temporal spread imaging to visualize propagation of epileptic activity.

PubMed

Shibata, Sumiya; Matsuhashi, Masao; Kunieda, Takeharu; Yamao, Yukihiro; Inano, Rika; Kikuchi, Takayuki; Imamura, Hisaji; Takaya, Shigetoshi; Matsumoto, Riki; Ikeda, Akio; Takahashi, Ryosuke; Mima, Tatsuya; Fukuyama, Hidenao; Mikuni, Nobuhiro; Miyamoto, Susumu

2017-05-01

We describe temporal spread imaging (TSI) that can identify the spatiotemporal pattern of epileptic activity using Magnetoencephalography (MEG). A three-dimensional grid of voxels covering the brain is created. The array-gain minimum-variance spatial filter is applied to an interictal spike to estimate the magnitude of the source and the time (Ta) when the magnitude exceeds a predefined threshold at each voxel. This calculation is performed through all spikes. Each voxel has the mean Ta () and spike number (N sp ), which is the number of spikes whose source exceeds the threshold. Then, a random resampling method is used to determine the cutoff value of N sp for the statistically reproducible pattern of the activity. Finally, all the voxels where the source exceeds the threshold reproducibly shown on the MRI with a color scale representing . Four patients with intractable mesial temporal lobe epilepsy (MTLE) were analyzed. In three patients, the common pattern of the overlap between the propagation and the hypometabolism shown by fluorodeoxyglucose-positron emission tomography (FDG-PET) was identified. TSI can visualize statistically reproducible patterns of the temporal and spatial spread of epileptic activity. TSI can assess the statistical significance of the spatiotemporal pattern based on its reproducibility. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Detection and quantification system for monitoring instruments

DOEpatents

Dzenitis, John M [Danville, CA; Hertzog, Claudia K [Houston, TX; Makarewicz, Anthony J [Livermore, CA; Henderer, Bruce D [Livermore, CA; Riot, Vincent J [Oakland, CA

2008-08-12

A method of detecting real events by obtaining a set of recent signal results, calculating measures of the noise or variation based on the set of recent signal results, calculating an expected baseline value based on the set of recent signal results, determining sample deviation, calculating an allowable deviation by multiplying the sample deviation by a threshold factor, setting an alarm threshold from the baseline value plus or minus the allowable deviation, and determining whether the signal results exceed the alarm threshold.

Modelling the Future Hydroclimatology of the Lower Fraser River and its Impacts on the Spawning Migration Survival of Sockeye Salmon

NASA Technical Reports Server (NTRS)

Hague, M. J.; Ferrari, M. R.; Miller, J. R.; Patterson, D. A.; Russell, G. L.; Farrell, A.P.; Hinch, S. G.

2010-01-01

Short episodic high temperature events can be lethal for migrating adult Pacific salmon (Oncorhynchus spp.). We downscaled temperatures for the Fraser River, British Columbia to evaluate the impact of climate warming on the frequency of exceeding thermal thresholds associated with salmon migratory success. Alarmingly, a modest 1.0 C increase in average summer water temperature over 100 years (1981-2000 to 2081-2100) tripled the number of days per year exceeding critical salmonid thermal thresholds (i.e. 19.0 C). Refined thresholds for two populations (Gates Creek and Weaver Creek) of sockeye salmon (Oncorhynchus nerka) were defined using physiological constraint models based on aerobic scope. While extreme temperatures leading to complete aerobic collapse remained unlikely under our warming scenario, both populations were increasingly forced to migrate upriver at reduced levels of aerobic performance (e.g. in 80% of future simulations, => 90% of salmon encountered temperatures exceeding population specific thermal optima for maximum aerobic scope; T(sub opt)) = 16.3 C for Gates Creek and T(sub sopt)=14.5 C for Weaver Creek). Assuming recent changes to river entry timing persist, we also predicted dramatic increases in the probability of freshwater mortality for Weaver Creek salmon due to reductions in aerobic, and general physiological, performance (e.g. in 42% of future simulations =>50% of Weaver Creek fish exceeded temperature thresholds associated with 0 - 60% of maximum aerobic scope). Potential for adaptation via directional selection on run-timing was more evident for the Weaver Creek population. Early entry Weaver Creek fish experienced 25% (range: 15 - 31%) more suboptimal temperatures than late entrants, compared with an 8% difference (range: 0 - 17%) between early and late Gates Creek fish. Our results emphasize the need to consider daily temperature variability in association with population-specific differences in behaviour and physiological constraints when forecasting impacts of climate change on migratory survival of aquatic species.

Health Risk Assessment of Dietary Cadmium Intake: Do Current Guidelines Indicate How Much is Safe?

PubMed

Satarug, Soisungwan; Vesey, David A; Gobe, Glenda C

2017-03-01

Cadmium (Cd), a food-chain contaminant, is a significant health hazard. The kidney is one of the primary sites of injury after chronic Cd exposure. Kidney-based risk assessment establishes the urinary Cd threshold at 5.24 μg/g creatinine, and tolerable dietary intake of Cd at 62 μg/day per 70-kg person. However, cohort studies show that dietary Cd intake below a threshold limit and that tolerable levels may increase the risk of death from cancer, cardiovascular disease, and Alzheimer's disease. We evaluated if the current tolerable dietary Cd intake guideline and urinary Cd threshold limit provide sufficient health protection. Staple foods constitute 40-60% of total dietary Cd intake by average consumers. Diets high in shellfish, crustaceans, mollusks, spinach, and offal add to dietary Cd sources. Modeling studies predict the current tolerable dietary intake corresponding to urinary Cd of 0.70-1.85 μg/g creatinine in men and 0.95-3.07 μg/g creatinine in women. Urinary Cd levels of < 1 μg/g creatinine were associated with progressive kidney dysfunction and peripheral vascular disease. A urinary Cd of 0.37 μg/g creatinine was associated with breast cancer, whereas dietary Cd of 16-31.5 μg/day was associated with 25-94% increase in risk of estrogen receptor-positive breast cancer. Modeling shows that dietary intake levels for Cd exceed the levels associated with kidney damage and many other adverse outcomes. Thus, the threshold level of urinary Cd should be re-evaluated. A more restrictive dietary intake guideline would afford enhanced health protection from this pervasive toxic metal. Citation: Satarug S, Vesey DA, Gobe GC. 2017. Health risk assessment of dietary cadmium intake: do current guidelines indicate how much is safe? Environ Health Perspect 125:284-288; http://dx.doi.org/10.1289/EHP108.

Differential Accumulation of Mercury and Selenium in Brown Trout Tissues of a High-Gradient Urbanized Stream in Colorado, USA.

PubMed

Herrmann, S J; Nimmo, D R; Carsella, J S; Herrmann-Hoesing, L M; Turner, J A; Gregorich, J M; Heuvel, B D Vanden; Nehring, R B; Foutz, H P

2016-02-01

Total mercury (THg) and selenium (Se) were analyzed by Inductively Coupled Plasma Mass Spectrometry in 11 internal and external tissues and stomach contents from 23 brown trout, Salmo trutta, of a 22.9-km reach of a high-gradient stream (upper Fountain Creek) in Colorado, USA, impacted by coal-fired power plants, shale deposits, and urbanization. Trout and water were sampled from four sites ranging from 2335 to 1818 m elevation. Lengths, weights, and ages of fish between pairs of the four sites were not significantly different. The dry weight (dw) to wet weight (ww) conversion factor for each tissue was calculated with egg-ovary highest at 0.379 and epaxial muscle fourth highest at 0.223. THg and Se in stomach contents indicated diet and not ambient water was the major source of Hg and Se bioaccumulated. Mean THg ww in kidney was 40.33 µg/kg, and epaxial muscle second highest at 36.76 µg/kg. None of the tissues exceeded the human critical threshold for Hg. However, all 23 trout had at least one tissue type that exceeded 0.02 mg/kg THg ww for birds, and four trout tissues exceeded 0.1 mg/kg THg ww for mammals, indicating that piscivorous mammals and birds should be monitored. Se concentrations in tissues varied depending on ww or dw listing. Mean Se dw in liver was higher than ovary at the uppermost site and the two lower sites. Liver tissue, in addition to egg-ovary, should be utilized as an indicator tissue for Se toxicity.

The prehospital intravenous access assessment: a prospective study on intravenous access failure and access delay in prehospital emergency medicine.

PubMed

Prottengeier, Johannes; Albermann, Matthias; Heinrich, Sebastian; Birkholz, Torsten; Gall, Christine; Schmidt, Joachim

2016-12-01

Intravenous access in prehospital emergency care allows for early administration of medication and extended measures such as anaesthesia. Cannulation may, however, be difficult, and failure and resulting delay in treatment and transport may have negative effects on the patient. Therefore, our study aims to perform a concise assessment of the difficulties of prehospital venous cannulation. We analysed 23 candidate predictor variables on peripheral venous cannulations in terms of cannulation failure and exceedance of a 2 min time threshold. Multivariate logistic regression models were fitted for variables of predictive value (P<0.25) and evaluated by the area under the curve (AUC>0.6) of their respective receiver operating characteristic curve. A total of 762 intravenous cannulations were enroled. In all, 22% of punctures failed on the first attempt and 13% of punctures exceeded 2 min. Model selection yielded a three-factor model (vein visibility without tourniquet, vein palpability with tourniquet and insufficient ambient lighting) of fair accuracy for the prediction of puncture failure (AUC=0.76) and a structurally congruent model of four factors (failure model factors plus vein visibility with tourniquet) for the exceedance of the 2 min threshold (AUC=0.80). Our study offers a simple assessment to identify cases of difficult intravenous access in prehospital emergency care. Of the numerous factors subjectively perceived as possibly exerting influences on cannulation, only the universal - not exclusive to emergency care - factors of lighting, vein visibility and palpability proved to be valid predictors of cannulation failure and exceedance of a 2 min threshold.

26 CFR 1.367(a)-3 - Treatment of transfers of stock or securities to foreign corporations.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) (i.e., there is no control group). For purposes of this paragraph (c)(1)(ii), any stock of the... for purposes of determining whether the 50-percent threshold is exceeded or whether a control group... under paragraph (c)(1)(i) of this section is exceeded or whether a control group under paragraph (c)(1...

26 CFR 1.367(a)-3 - Treatment of transfers of stock or securities to foreign corporations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... control group). For purposes of this paragraph (c)(1)(ii), any stock of the transferee foreign corporation... for purposes of determining whether the 50-percent threshold is exceeded or whether a control group... under paragraph (c)(1)(i) of this section is exceeded or whether a control group under paragraph (c)(1...

26 CFR 1.367(a)-3 - Treatment of transfers of stock or securities to foreign corporations.

Code of Federal Regulations, 2012 CFR

2012-04-01

... control group). For purposes of this paragraph (c)(1)(ii), any stock of the transferee foreign corporation... for purposes of determining whether the 50-percent threshold is exceeded or whether a control group... under paragraph (c)(1)(i) of this section is exceeded or whether a control group under paragraph (c)(1...

26 CFR 1.367(a)-3 - Treatment of transfers of stock or securities to foreign corporations.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) (i.e., there is no control group). For purposes of this paragraph (c)(1)(ii), any stock of the... for purposes of determining whether the 50-percent threshold is exceeded or whether a control group... under paragraph (c)(1)(i) of this section is exceeded or whether a control group under paragraph (c)(1...

26 CFR 1.367(a)-3 - Treatment of transfers of stock or securities to foreign corporations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... control group). For purposes of this paragraph (c)(1)(ii), any stock of the transferee foreign corporation... for purposes of determining whether the 50-percent threshold is exceeded or whether a control group... under paragraph (c)(1)(i) of this section is exceeded or whether a control group under paragraph (c)(1...

Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

USGS Publications Warehouse

Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

2012-01-01

Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (−1 yr−1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha−1 yr−1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha−1 yr−1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO3− threshold at which ecological effects are thought to occur. Based on an NO3− threshold of 0.5 μmol L−1, N deposition exceeds CLNdep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

USGS Publications Warehouse

Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

2012-01-01

Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (-1 yr-1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha-1 yr-1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha-1 yr-1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO3- threshold at which ecological effects are thought to occur. Based on an NO3- threshold of 0.5 μmol L-1, N deposition exceeds CLNdep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

Increased seizure susceptibility and other toxicity symptoms following acute sulforaphane treatment in mice.

PubMed

Socała, Katarzyna; Nieoczym, Dorota; Kowalczuk-Vasilev, Edyta; Wyska, Elżbieta; Wlaź, Piotr

2017-07-01

Activation of Nrf2 with sulforaphane has recently gained attention as a new therapeutic approach in the treatment of many diseases, including epilepsy. As a plant-derived compound, sulforaphane is considered to be safe and well-tolerated. It is widely consumed, also by patients suffering from seizure and taking antiepileptic drugs, but no toxicity profile of sulforaphane exists. Since many natural remedies and dietary supplements may increase seizure risk and potentially interact with antiepileptic drugs, the aim of our study was to investigate the acute effects of sulforaphane on seizure thresholds and activity of some first- and second-generation antiepileptic drugs in mice. In addition, some preliminary toxicity profile of sulforaphane in mice after intraperitoneal injection was evaluated. The LD 50 value of sulforaphane in mice was estimated at 212.67mg/kg, while the TD 50 value - at 191.58mg/kg. In seizure tests, sulforaphane at the highest dose tested (200mg/kg) significantly decreased the thresholds for the onset of the first myoclonic twitch and generalized clonic seizure in the iv PTZ test as well as the threshold for the 6Hz-induced psychomotor seizure. At doses of 10-200mg/kg, sulforaphane did not affect the threshold for the iv PTZ-induced forelimb tonus or the threshold for maximal electroshock-induced hindlimb tonus. Interestingly, sulforaphane (at 100mg/kg) potentiated the anticonvulsant efficacy of carbamazepine in the maximal electroshock seizure test. This interaction could have been pharmacokinetic in nature, as sulforaphane increased concentrations of carbamazepine in both serum and brain tissue. The toxicity study showed that high doses of sulforaphane produced marked sedation (at 150-300mg/kg), hypothermia (at 150-300mg/kg), impairment of motor coordination (at 200-300mg/kg), decrease in skeletal muscle strength (at 250-300mg/kg), and deaths (at 200-300mg/kg). Moreover, blood analysis showed leucopenia in mice injected with sulforaphane at 200mg/kg. In conclusion, since sulforaphane was proconvulsant at a toxic dose, the safety profile and the risk-to-benefit ratio of sulforaphane usage in epileptic patients should be further evaluated. Copyright © 2017 Elsevier Inc. All rights reserved.

Differential reconstructed gene interaction networks for deriving toxicity threshold in chemical risk assessment.

PubMed

Yang, Yi; Maxwell, Andrew; Zhang, Xiaowei; Wang, Nan; Perkins, Edward J; Zhang, Chaoyang; Gong, Ping

2013-01-01

Pathway alterations reflected as changes in gene expression regulation and gene interaction can result from cellular exposure to toxicants. Such information is often used to elucidate toxicological modes of action. From a risk assessment perspective, alterations in biological pathways are a rich resource for setting toxicant thresholds, which may be more sensitive and mechanism-informed than traditional toxicity endpoints. Here we developed a novel differential networks (DNs) approach to connect pathway perturbation with toxicity threshold setting. Our DNs approach consists of 6 steps: time-series gene expression data collection, identification of altered genes, gene interaction network reconstruction, differential edge inference, mapping of genes with differential edges to pathways, and establishment of causal relationships between chemical concentration and perturbed pathways. A one-sample Gaussian process model and a linear regression model were used to identify genes that exhibited significant profile changes across an entire time course and between treatments, respectively. Interaction networks of differentially expressed (DE) genes were reconstructed for different treatments using a state space model and then compared to infer differential edges/interactions. DE genes possessing differential edges were mapped to biological pathways in databases such as KEGG pathways. Using the DNs approach, we analyzed a time-series Escherichia coli live cell gene expression dataset consisting of 4 treatments (control, 10, 100, 1000 mg/L naphthenic acids, NAs) and 18 time points. Through comparison of reconstructed networks and construction of differential networks, 80 genes were identified as DE genes with a significant number of differential edges, and 22 KEGG pathways were altered in a concentration-dependent manner. Some of these pathways were perturbed to a degree as high as 70% even at the lowest exposure concentration, implying a high sensitivity of our DNs approach. Findings from this proof-of-concept study suggest that our approach has a great potential in providing a novel and sensitive tool for threshold setting in chemical risk assessment. In future work, we plan to analyze more time-series datasets with a full spectrum of concentrations and sufficient replications per treatment. The pathway alteration-derived thresholds will also be compared with those derived from apical endpoints such as cell growth rate.

Application of the threshold of toxicological concern concept to pharmaceutical manufacturing operations.

PubMed

Dolan, David G; Naumann, Bruce D; Sargent, Edward V; Maier, Andrew; Dourson, Michael

2005-10-01

A scientific rationale is provided for estimating acceptable daily intake values (ADIs) for compounds with limited or no toxicity information to support pharmaceutical manufacturing operations. These ADIs are based on application of the "thresholds of toxicological concern" (TTC) principle, in which levels of human exposure are estimated that pose no appreciable risk to human health. The same concept has been used by the US Food and Drug Administration (FDA) to establish "thresholds of regulation" for indirect food additives and adopted by the Joint FAO/WHO Expert Committee on Food Additives for flavoring substances. In practice, these values are used as a statement of safety and indicate when no actions need to be taken in a given exposure situation. Pharmaceutical manufacturing relies on ADIs for cleaning validation of process equipment and atypical extraneous matter investigations. To provide practical guidance for handling situations where relatively unstudied compounds with limited or no toxicity data are encountered, recommendations are provided on ADI values that correspond to three categories of compounds: (1) compounds that are likely to be carcinogenic, (2) compounds that are likely to be potent or highly toxic, and (3) compounds that are not likely to be potent, highly toxic or carcinogenic. Corresponding ADIs for these categories of materials are 1, 10, and 100 microg/day, respectively.

Bidirectional control system for energy flow in solar powered flywheel

NASA Technical Reports Server (NTRS)

Nola, Frank J. (Inventor)

1987-01-01

An energy storage system for a spacecraft is provided which employs a solar powered flywheel arrangement including a motor/generator which, in different operating modes, drives the flywheel and is driven thereby. A control circuit, including a threshold comparator, senses the output of a solar energy converter, and when a threshold voltage is exceeded thereby indicating the availability of solar power for the spacecraft loads, activates a speed control loop including the motor/generator so as to accelerate the flywheel to a constant speed and thereby store mechanical energy, while also supplying energy from the solar converter to the loads. Under circumstances where solar energy is not available and thus the threshold voltage is not exceeded, the control circuit deactivates the speed control loop and activates a voltage control loop that provides for operation of the motor as a generator so that mechanical energy from the flywheel is converted into electrical energy for supply to the spacecraft loads.

Risk characterization of methyl tertiary butyl ether (MTBE) in tap water.

PubMed

Stern, B R; Tardiff, R G

1997-12-01

Methyl tertiary butyl ether (MTBE) can enter surface water and groundwater through wet atmospheric deposition or as a result of fuel leaks and spills. About 30% of the U.S. population lives in areas where MTBE is in regular use. Ninety-five percent of this population is unlikely to be exposed to MTBE in tap water at concentrations exceeding 2 ppb, and most will be exposed to concentrations that are much lower and may be zero. About 5% of this population may be exposed to higher levels of MTBE in tap water, resulting from fuel tank leaks and spills into surface or groundwater used for potable water supplies. This paper describes the concentration ranges found and anticipated in surface and groundwater, and estimates the distribution of doses experienced by humans using water containing MTBE to drink, prepare food, and shower/bathe. The toxic properties (including potency) of MTBE when ingested, inhaled, and in contact with the skin are summarized. Using a range of human toxic potency values derived from animal studies, margins of exposure (MOE) associated with alternative chronic exposure scenarios are estimated to range from 1700 to 140,000. Maximum concentrations of MTBE in tap water anticipated not to cause adverse health effects are determined to range from 700 to 14,000 ppb. The results of this analysis demonstrate that no health risks are likely to be associated with chronic and subchronic human exposures to MTBE in tap water. Although some individuals may be exposed to very high concentrations of MTBE in tap water immediately following a localized spill, these exposures are likely to be brief in duration due to large-scale dilution and rapid volatilization of MTBE, the institution of emergency response and remediation measures to minimize human exposures, and the low taste and odor thresholds of MTBE which ensure that its presence in tap water is readily detected at concentrations well below the threshold for human injury.

Measuring total mercury due to small-scale gold mining activities to determine community vulnerability in Cihonje, Central Java, Indonesia.

PubMed

Sari, Mega M; Inoue, Takanobu; Matsumoto, Yoshitaka; Yokota, Kuriko

2016-01-01

This research is comparative study of gold mining and non-gold mining areas, using four community vulnerability indicators. Vulnerability indicators are exposure degree, contamination rate, chronic, and acute toxicity. Each indicator used different samples, such as wastewater from gold mining process, river water from Tajum river, human hair samples, and health questionnaire. This research used cold vapor atomic absorption spectrometry to determine total mercury concentration. The result showed that concentration of total mercury was 2,420 times than the maximum content of mercury permitted in wastewater based on the Indonesian regulation. Moreover, the mercury concentration in river water reached 685 ng/l, exceeding the quality threshold standards of the World Health Organization (WHO). The mercury concentration in hair samples obtained from the people living in the research location was considered to identify the health quality level of the people or as a chronic toxicity indicator. The highest mercury concentration--i.e. 17 ng/mg, was found in the gold mining respondents. Therefore, based on the total mercury concentration in the four indicators, the community in the gold mining area were more vulnerable to mercury than communities in non-gold mining areas. It was concluded that the community in gold mining area was more vulnerable to mercury contamination than the community in non-gold mining area.

Neurotoxicity of lead, methylmercury, and PCBs in relation to the Great Lakes.

PubMed Central

Rice, D C

1995-01-01

There is ample evidence identifying lead, methylmercury, and polychlorinated biphenyls (PCBs) as neurotoxic agents. A large body of data on the neurotoxicity of lead, based on both epidemiologic studies in children and animal models of developmental exposure, reveals that body burdens of lead typical of people in industrialized environments produce behavioral impairment. Methylmercury was identified as a neurotoxicant in both adults and the developing organism based on episodes of human poisoning: these effects have been replicated and extended in animals. High-dose PCB exposure was recognized as a developmental toxicant as a result of several episodes of contamination of cooking oil. The threshold for PCB neurotoxicity in humans is less clear, although research in animals suggests that relatively low-level exposure produces behavioral impairment and other toxic effects. Tissue levels in fish below which human health would not be adversely affected were estimated for methylmercury and PCBs based on calculated reference doses (RfDs) and estimated fish intake. Present levels in fish tissue in the Great Lakes exceed these levels for both neurotoxicants. Great Lakes fish and water do not pose a particular hazard for increased lead intake. However, the fact that the present human body burden is in a range at which functional deficits are probable suggests that efforts should be made to eliminate point sources of lead contamination in the Great Lakes basin. PMID:8635443

Can we reduce the number of fish in the OECD acute toxicity test?

PubMed

Rufli, Hans; Springer, Timothy A

2011-04-01

OECD (Organisation for Economic Co-operation and Development) Guideline 203, Fish Acute Toxicity Test, states that the test should be performed using at least five concentrations in a geometric series with a separation factor not exceeding 2.2, with at least seven fish per concentration. However, the efficiency of this design can be questioned, because it often results in only one concentration that causes partial mortality (mortality >0% and <100%). We performed Monte Carlo computer simulations to assess whether more efficient designs could allow reductions in fish use. Simulations indicated that testing with six fish per concentration could yield 50% lethal concentration (LC50) estimates of quality similar to those obtained using seven fish. Experts attending a workshop organized to consider this finding and to identify the best methods for reducing fish use concluded that significant reductions could best be achieved by modifying the test paradigm. They suggested initiating testing using a 96-h fish embryo test instead of juvenile fish to cover the range from the upper threshold concentration (the lowest 50% effective concentration [EC50] in existing algae and daphnia studies) to the highest concentration with no mortality. This would be followed by a confirmatory limit test with juvenile fish at the highest concentration with no mortality or by a full test with juvenile fish, if a point estimate of the LC50 is required. Copyright © 2011 SETAC.

Hazardous waste status of discarded electronic cigarettes.

PubMed

Krause, Max J; Townsend, Timothy G

2015-05-01

The potential for disposable electronic cigarettes (e-cigarettes) to be classified as hazardous waste was investigated. The Toxicity Characteristic Leaching Procedure (TCLP) was performed on 23 disposable e-cigarettes in a preliminary survey of metal leaching. Based on these results, four e-cigarette products were selected for replicate analysis by TCLP and the California Waste Extraction Test (WET). Lead was measured in leachate as high as 50mg/L by WET and 40mg/L by TCLP. Regulatory thresholds were exceeded by two of 15 products tested in total. Therefore, some e-cigarettes would be toxicity characteristic (TC) hazardous waste but a majority would not. When disposed in the unused form, e-cigarettes containing nicotine juice would be commercial chemical products (CCP) and would, in the United States (US), be considered a listed hazardous waste (P075). While household waste is exempt from hazardous waste regulation, there are many instances in which such waste would be subject to regulation. Manufactures and retailers with unused or expired e-cigarettes or nicotine juice solution would be required to manage these as hazardous waste upon disposal. Current regulations and policies regarding the availability of nicotine-containing e-cigarettes worldwide were reviewed. Despite their small size, disposable e-cigarettes are consumed and discarded much more quickly than typical electronics, which may become a growing concern for waste managers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Element concentrations on Hypogymnia physodes after three years of transplanting along Lake Michigan

USGS Publications Warehouse

Bennett, J.P.; Dibben, M.J.; Lyman, K.J.

1996-01-01

Improvements in air quality in air polluted areas are often followed by recolonization of habitats by sensitive lichens that had died out when air quality was worse. To test the hypothesis that air quality at Indiana Dunes National Lakeshore has improved such that lichens could recolonize the area, samples of a species that once grew in the park, Hypogymnia physodes, were transplanted from Door County, Wisconsin to the park and three other sites along the western shore of Lake Michigan, including one at the site of origin as a control. The lichens were sampled for 3 years and tissue concentrations of 20 chemical elements were measured. There were no significant differences between concentrations over the 3 year study duration at the control site in Door County, suggesting that transplanting itself had no impacts on tissue concentrations. All but two elements increased in concentration from north to south with the greatest increases occurring in the third year of the study. Lichens at Indiana Dunes at the end of the study had suffered severe mortality. Chromium increased the most from north to south but concentrations were not higher than maxima observed in other studies. Arsenic and sulfur, however, exceeded known toxic thresholds or maxima observed in other studies on this species. Four hypotheses are presented to explain the toxicity of elements to this species.

Rainfall thresholds for possible landslide occurrence in Italy

NASA Astrophysics Data System (ADS)

Peruccacci, Silvia; Brunetti, Maria Teresa; Gariano, Stefano Luigi; Melillo, Massimo; Rossi, Mauro; Guzzetti, Fausto

2017-08-01

The large physiographic variability and the abundance of landslide and rainfall data make Italy an ideal site to investigate variations in the rainfall conditions that can result in rainfall-induced landslides. We used landslide information obtained from multiple sources and rainfall data captured by 2228 rain gauges to build a catalogue of 2309 rainfall events with - mostly shallow - landslides in Italy between January 1996 and February 2014. For each rainfall event with landslides, we reconstructed the rainfall history that presumably caused the slope failure, and we determined the corresponding rainfall duration D (in hours) and cumulated event rainfall E (in mm). Adopting a power law threshold model, we determined cumulated event rainfall-rainfall duration (ED) thresholds, at 5% exceedance probability, and their uncertainty. We defined a new national threshold for Italy, and 26 regional thresholds for environmental subdivisions based on topography, lithology, land-use, land cover, climate, and meteorology, and we used the thresholds to study the variations of the rainfall conditions that can result in landslides in different environments, in Italy. We found that the national and the environmental thresholds cover a small part of the possible DE domain. The finding supports the use of empirical rainfall thresholds for landslide forecasting in Italy, but poses an empirical limitation to the possibility of defining thresholds for small geographical areas. We observed differences between some of the thresholds. With increasing mean annual precipitation (MAP), the thresholds become higher and steeper, indicating that more rainfall is needed to trigger landslides where the MAP is high than where it is low. This suggests that the landscape adjusts to the regional meteorological conditions. We also observed that the thresholds are higher for stronger rocks, and that forested areas require more rainfall than agricultural areas to initiate landslides. Finally, we observed that a 20% exceedance probability national threshold was capable of predicting all the rainfall-induced landslides with casualties between 1996 and 2014, and we suggest that this threshold can be used to forecast fatal rainfall-induced landslides in Italy. We expect the method proposed in this work to define and compare the thresholds to have an impact on the definition of new rainfall thresholds for possible landslide occurrence in Italy, and elsewhere.

Quaternary IPM (integrated pest management)--concept for the control of powdery mildew in sugar beets.

PubMed

Wolf, P F J; Verreet, A

2008-01-01

Powdery mildew, caused by Erysiphe betae (Vanha) Weltzien, may be assumed as an important leaf disease in sugar beet growing areas of central Europe. Although the causal agent is mainly adapted to arid climatic zones, the disease is appearing every year, where the extent of infection is mainly dependent on weather conditions and susceptibility of cultivar. The losses caused by powdery mildew seldom exceed 10% of sugar yield; moreover, losses are likely only under the condition that the epidemic onset occurs before end-August. Nevertheless, the epidemic onset varies in a wide range, as there are years with high incidence followed by growing periods without severe infection. Therefore, in order to have a flexible control of the disease, where the use of fungicides could be minimised to an essential amount, a quaternary IPM (Integrated Pest Management) -concept was developed. The development is based on epidemiological field studies (Germany, 1993-2004, n = 76) of sugar beet leaf diseases under variation of year, site and cultivar. Efficacy of fungicide treatment timing was assessed in relation to the epidemic development. Comparison of treatments comprised fungicide sprays carried out from disease initiation till later stages of the epidemic. Additionally, the assessments were performed in relation to an untreated and a healthy control--the latter was three times treated according to a treatment regime with three to four week intervals. The effect of different application timings was measured by the potential of disease and yield loss control. The quaternary concept combines the advantages of four elements in order to compensate the constraints of the single tools: The period without disease risk is determined by a so-called negative-prognosis (i). First symptoms appear in the period from mid-July till the beginning of September. If disease initiation cannot be excluded, field observations by a sample of 100 leaves are advised. The disease scores enable the appliance of action thresholds (ii). The latter are defined as early stages of the epidemic in order to optimize the efficiency of fungicide treatments. For an initial treatment a threshold of 5% infected leaves is defined. However, incidence in the height of action thresholds is not affecting an instant damage. The stage when a sugar beet is damaged effectively is rather defined by the economic damage threshold (iii). As a consequence, because exceeding of action threshold doesn't implicate immediate yield risk, loss prediction (iv) is required. The loss prediction assesses the likelihood of disease progress will exceed the economic damage threshold at harvest time. Loss risk is existent in case of action threshold exceeding till mid-August if cultivar susceptibility is low respectively end-August if susceptibility is high.

Health hazards of ultrafine metal and metal oxide powders

NASA Technical Reports Server (NTRS)

Boylen, G. W., Jr.; Chamberlin, R. I.; Viles, F. J.

1969-01-01

Study reveals that suggested threshold limit values are from two to fifty times lower than current recommended threshold limit values. Proposed safe limits of exposure to the ultrafine dusts are based on known toxic potential of various materials as determined in particle size ranges.

Pollutant threshold concentration determination in marine ecosystems using an ecological interaction endpoint.

PubMed

Wang, Changyou; Liang, Shengkang; Guo, Wenting; Yu, Hua; Xing, Wenhui

2015-09-01

The threshold concentrations of pollutants are determined by extrapolating single-species effect data to community-level effects. This assumes the most sensitive endpoint of the life cycle of individuals and the species sensitivity distribution from single-species toxic effect tests, thus, ignoring the ecological interactions. The uncertainties due to this extrapolation can be partially overcome using the equilibrium point of a customized ecosystem. This method incorporates ecological interactions and integrates the effects on growth, survival, and ingestion into a single effect measure, the equilibrium point excursion in the customized ecosystem, in order to describe the toxic effects on plankton. A case study showed that the threshold concentration of copper calculated with the endpoint of the equilibrium point was 10 μg L(-1), which is significantly different from the threshold calculated with a single-species endpoint. The endpoint calculated using this method provides a more relevant measure of the ecological impact than any single individual-level endpoint. Copyright © 2015 Elsevier Ltd. All rights reserved.

Calculation and evaluation of sediment effect concentrations for the amphipod Hyalella azteca and the midge Chironomus riparius

USGS Publications Warehouse

Ingersoll, Christopher G.; Haverland, Pamela S.; Brunson, Eric L.; Canfield, Timothy J.; Dwyer, F. James; Henke, Chris; Kemble, Nile E.; Mount, David R.; Fox, Richard G.

1996-01-01

Procedures are described for calculating and evaluating sediment effect concentrations (SECs) using laboratory data on the toxicity of contaminants associated with field-collected sediment to the amphipod Hyalella azteca and the midge Chironomus riparius. SECs are defined as the concentrations of individual contaminants in sediment below which toxicity is rarely observed and above which toxicity is frequently observed. The objective of the present study was to develop SECs to classify toxicity data for Great Lake sediment samples tested with Hyalella azteca and Chironomus riparius. This SEC database included samples from additional sites across the United States in order to make the database as robust as possible. Three types of SECs were calculated from these data: (1) Effect Range Low (ERL) and Effect Range Median (ERM), (2) Threshold Effect Level (TEL) and Probable Effect Level (PEL), and (3) No Effect Concentration (NEC). We were able to calculate SECs primarily for total metals, simultaneously extracted metals, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The ranges of concentrations in sediment were too narrow in our database to adequately evaluate SECs for butyltins, methyl mercury, polychlorinated dioxins and furans, or chlorinated pesticides. About 60 to 80% of the sediment samples in the database are correctly classified as toxic or not toxic depending on type of SEC evaluated. ERMs and ERLs are generally as reliable as paired PELs and TELs at classifying both toxic and non-toxic samples in our database. Reliability of the SECs in terms of correctly classifying sediment samples is similar between ERMs and NECs; however, ERMs minimize Type I error (false positives) relative to ERLs and minimize Type II error (false negatives) relative to NECs. Correct classification of samples can be improved by using only the most reliable individual SECs for chemicals (i.e., those with a higher percentage of correct classification). SECs calculated using sediment concentrations normalized to total organic carbon (TOC) concentrations did not improve the reliability compared to SECs calculated using dry-weight concentrations. The range of TOC concentrations in our database was relatively narrow compared to the ranges of contaminant concentrations. Therefore, normalizing dry-weight concentrations to a relatively narrow range of TOC concentrations had little influence on relative concentra of contaminants among samples. When SECs are used to conduct a preliminary screening to predict the potential for toxicity in the absence of actual toxicity testing, a low number of SEC exceedances should be used to minimize the potential for false negatives; however, the risk of accepting higher false positives is increased.

Reduced Toxicity High Performance Monopropellant

DTIC Science & Technology

2011-09-01

M315E Distribution A: Approved for public release; distribution unlimited AF - M315E Desirable Properties Characteristic Objective D it *I 3450 N /L...required AF M315E d- excee s SOTA monopropellant (45%) and bipropellant (8%) Next generation exceeds SOTA monopropellant (66%) and bipropellant (23...inert mass fraction Distribution A: Approved for public release; distribution unlimited Toxicity Assessment of AF - M315E Toxicity Testing Results

75 FR 32637 - Defense Federal Acquisition Regulation Supplement; Trade Agreements Thresholds (DFARS Case 2009...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-08

... exceeding) exceeding) WTO GPA $203,000 $7,804,000 FTAs: Australia FTA 70,079 7,804,000 Bahrain FTA 203,000 9,110,318 CAFTA-DR (Costa Rica, Dominican 70,079 7,804,000 Republic, El Salvador, Guatemala, Honduras, and Nicaragua) Chile FTA 70,079 7,804,000 Morocco FTA 203,000 7,804,000 NAFTA: --Canada 25,000 9,110...

Application of Key Events and Analysis to Chemical Carcinogens and Noncarcinogens

EPA Science Inventory

The existence of thresholds for toxicants is a matter of debate in chemical rsk assessment and regulation. Current risk assessment methods are based on the assumption that, in the basense of sufficient data, carcinogenesis does not have a threshold, while non-carcinogenic endpoi...

Development and evaluation of consensus-based sediment effect concentrations for polychlorinated biphenyls

USGS Publications Warehouse

MacDonald, Donald D.; Dipinto, Lisa M.; Field, Jay; Ingersoll, Christopher G.; Long, Edward R.; Swartz, Richard C.

2000-01-01

Sediment-quality guidelines (SQGs) have been published for polychlorinated biphenyls (PCBs) using both empirical and theoretical approaches. Empirically based guidelines have been developed using the screening-level concentration, effects range, effects level, and apparent effects threshold approaches. Theoretically based guidelines have been developed using the equilibrium-partitioning approach. Empirically-based guidelines were classified into three general categories, in accordance with their original narrative intents, and used to develop three consensus-based sediment effect concentrations (SECs) for total PCBs (tPCBs), including a threshold effect concentration, a midrange effect concentration, and an extreme effect concentration. Consensus-based SECs were derived because they estimate the central tendency of the published SQGs and, thus, reconcile the guidance values that have been derived using various approaches. Initially, consensus-based SECs for tPCBs were developed separately for freshwater sediments and for marine and estuarine sediments. Because the respective SECs were statistically similar, the underlying SQGs were subsequently merged and used to formulate more generally applicable SECs. The three consensus-based SECs were then evaluated for reliability using matching sediment chemistry and toxicity data from field studies, dose-response data from spiked-sediment toxicity tests, and SQGs derived from the equilibrium-partitioning approach. The results of this evaluation demonstrated that the consensus-based SECs can accurately predict both the presence and absence of toxicity in field-collected sediments. Importantly, the incidence of toxicity increases incrementally with increasing concentrations of tPCBs. Moreover, the consensus-based SECs are comparable to the chronic toxicity thresholds that have been estimated from dose-response data and equilibrium-partitioning models. Therefore, consensus-based SECs provide a unifying synthesis of existing SQGs, reflect causal rather than correlative effects, and accurately predict sediment toxicity in PCB-contaminated sediments.

Improving sediment-quality guidelines for nickel: development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments

USGS Publications Warehouse

Vangheluwe, Marnix L. U.; Verdonck, Frederik A. M.; Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.; Schlekat, Christan E.; Rogevich Garman, Emily

2013-01-01

Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (AVS) and total organic carbon. The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea), and midges (Chironomus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel-spiked sediments. A species sensitivity distribution was elaborated based on 10% effective concentrations yielding a threshold value of 94 mg Ni/kg dry weight under reasonable worst-case conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (20% effective concentrations) and AVS and Fe, and these models were used to derive site-specific sediment-quality criteria. Normalization of toxicity values reduced the intersediment variability in toxicity values significantly for the amphipod species Hyalella azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126 mg to 281 mg Ni/kg dry weight, based on the AVS model, and 143 mg to 265 mg Ni/kg dry weight, based on the Fe model

THRESH—Software for tracking rainfall thresholds for landslide and debris-flow occurrence, user manual

USGS Publications Warehouse

Baum, Rex L.; Fischer, Sarah J.; Vigil, Jacob C.

2018-02-28

Precipitation thresholds are used in many areas to provide early warning of precipitation-induced landslides and debris flows, and the software distribution THRESH is designed for automated tracking of precipitation, including precipitation forecasts, relative to thresholds for landslide occurrence. This software is also useful for analyzing multiyear precipitation records to compare timing of threshold exceedance with dates and times of historical landslides. This distribution includes the main program THRESH for comparing precipitation to several kinds of thresholds, two utility programs, and a small collection of Python and shell scripts to aid the automated collection and formatting of input data and the graphing and further analysis of output results. The software programs can be deployed on computing platforms that support Fortran 95, Python 2, and certain Unix commands. The software handles rainfall intensity-duration thresholds, cumulative recent-antecedent precipitation thresholds, and peak intensity thresholds as well as various measures of antecedent precipitation. Users should have predefined rainfall thresholds before running THRESH.

Health benefit from decreasing exposure to heavy metals and metalloid after strict pollution control measures near a typical river basin area in China.

PubMed

Cao, Suzhen; Duan, Xiaoli; Ma, Yingqun; Zhao, Xiuge; Qin, Yanwen; Liu, Yan; Li, Sai; Zheng, Binghui; Wei, Fusheng

2017-10-01

The metal(loid) pollution still is a great concern due to the effects from urbanization and industrialization. While, the health risks from the toxic metal(loid)s could decrease if strict pollution control measures were adopted. However, few studies to date investigate the health risks of heavy metal(loid)s in a systematic river basin for the dependent residents, after taking pollution control measures. Thus, the contents of metal(loid)s (Cu, Pb, Zn, Cd, Mn, As) in surface water along a typical river basin were investigated in this study, and the potential non-carcinogenic and carcinogenic health risks posed to the residents were assessed. Although the soluble contents of Cu, Pb, Zn and Cd exceeded the respective thresholds in two sites located downstream the mine area, they were greatly decreased in comparison with previous contamination levels, and the soluble concentrations of all the metal(loid)s were within the relevant thresholds in the sites far away from the mining area. Moreover, the closer to the mining area, the higher the pollution levels of metal(loid)s. The total hazard index for non-carcinogenic risks of metal(loid)s were basically lower than the threshold (1) for the local population. Whereas, although the content of metal(loid)s were low (such as As), they could pose relative higher non-carcinogenic health risks. The result illustrated that pollution levels, toxicity of the contaminants and exposure behavior patterns all could contribute to the potential detrimental health risks. Additionally, the non-carcinogenic and carcinogenic risks from ingestion exposure were ∼2-∼4 orders of magnitude higher than those from dermal contact. The total carcinogenic risks were basically lower than the maximum tolerable levels (1.0 × 10 -4 ), indicating carcinogenic risks from most areas of the river could also be accepted. Among different population groups, heavy metal(loid)s posed relative higher non-carcinogenic and carcinogenic risks to the children in 0-5 years old. Fortunately, the surface water in most area of this basin is safe in usage for the local population and the health risks were basically acceptable in case exposed to the target metal(loid)s, after the river basin was in the charge of strict pollution control measures. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluating links between forest harvest and stream temperature threshold exceedances: the value of spatial and temporal data

Treesearch

Jeremiah D. Groom; Sherri L. Johnson; Joshua D. Seeds; George G. Ice

2017-01-01

We present the results of a replicated before-after-control-impact study on 33 streams to test the effectiveness of riparian rules for private and State forests at meeting temperature criteria in streams in western Oregon. Many states have established regulatory temperature thresholds, referred to as numeric criteria, to protect cold-water fishes such as salmon and...

Different strategies of cadmium detoxification in the submerged macrophyte Ceratophyllum demersum L.

PubMed

Andresen, Elisa; Mattusch, Jürgen; Wellenreuther, Gerd; Thomas, George; Arroyo Abad, Uriel; Küpper, Hendrik

2013-10-01

The heavy metal cadmium (Cd) is highly toxic to plants. To understand the mechanisms of tolerance and resistance to Cd, we treated the rootless, submerged macrophyte Ceratophyllum demersum L. with sub-micromolar concentrations of Cd under environmentally relevant conditions. X-ray fluorescence measurements revealed changing distribution patterns of Cd and Zn at non-toxic (0.2 nM, 2 nM), moderately toxic (20 nM) and highly toxic (200 nM) levels of Cd. Increasing Cd concentrations led to enhanced sequestration of Cd into non-photosynthetic tissues like epidermis and vein. At toxic Cd concentrations, Zn was redistributed and mainly found in the vein. Cd treatment induced the synthesis of phytochelatins (PCs) in the plants, with a threshold of induction already at 20 nM Cd for PC3. In comparison, in plants treated with Cu, elevated PC levels were detected only at the highest concentrations (100-200 nM Cu). Our results show that also non-accumulators like C. demersum store toxic metals in tissues where the heavy metal interferes least with metabolic pathways, but remaining toxicity interferes with micronutrient distribution. Furthermore, we found that the induction of phytochelatins is not proportional to metal concentration, but has a distinct threshold, specific for each PC species. Finally we could show that 20 nM Cd, which was previously regarded as non-toxic to most plants, already induces detoxifying mechanisms.

Intra-abdominal pressure during Pilates: unlikely to cause pelvic floor harm.

PubMed

Coleman, Tanner J; Nygaard, Ingrid E; Holder, Dannielle N; Egger, Marlene J; Hitchcock, Robert

2015-08-01

The objective was to describe the intra-abdominal pressures (IAP) generated during Pilates Mat and Reformer activities, and determine whether these activities generate IAP above a sit-to-stand threshold. Twenty healthy women with no symptomatic vaginal bulge, median age 43 (range 22-59 years), completed Pilates Mat and Reformer exercise routines each consisting of 11 exercises. IAP was collected by an intra-vaginal pressure transducer, transmitted wirelessly to a base station, and analyzed for maximal and area under the curve (AUC) IAP. There were no statistically significant differences in the mean maximal IAP between sit-to-stand and any of the Mat or Reformer exercises in the study population. Six to twenty-five percent of participants exceeded their individual mean maximal IAP sit-to-stand thresholds for 10 of the 22 exercises. When measuring AUC from 0 cm H2O, half the exercises exceeded the mean AUC of sit-to-stand, but only Pilates Reformer and Mat roll-ups exceeded the mean AUC of sit-to-stand when calculated from a threshold of 40 cm H2O (consistent with, for example, walking). Our results support recommending this series of introductory Pilates exercises, including five Mat exercises and six Reformer exercises to women desiring a low IAP exercise routine. More research is needed to determine the long-term effects of Pilates exercise on post-surgical exercise rehabilitation and pelvic floor health.

Intra-abdominal Pressure during Pilates: Unlikely to Cause Pelvic Floor Harm

PubMed Central

Coleman, Tanner J.; Holder, Dannielle N.; Egger, Marlene J.; Hitchcock, Robert

2015-01-01

Aims To describe intra-abdominal pressures (IAP) generated during Pilates Mat and Reformer activities, and determine whether these activities generate IAP above a sit-to-stand threshold. Methods Twenty healthy women with no symptomatic vaginal bulge, median age 43 (range 22 – 59 years), completed Pilates Mat and Reformer exercise routines each consisting of 11 exercises. IAP was collected by an intra-vaginal pressure transducer, transmitted wirelessly to a base station, and analyzed for maximal and area under the curve (AUC) IAP. Results There were no statistically significant differences in mean max IAP between sit-to-stand and any of the Mat or Reformer exercises in the study population. Six to twenty-five percent of participants exceeded their individual mean max IAP sit-to-stand thresholds for 10 of the 22 exercises. When measuring AUC from 0 cm H2O, half the exercises exceeded the mean AUC of sit-to-stand but only Pilates Reformer and Mat roll-ups exceeded the mean AUC of sit-to-stand when calculated from a threshold of 40 cm H2O (consistent with, for example, walking). Conclusion Our results support recommending this series of introductory Pilates exercises including five Mat exercises and six Reformer exercises to women desiring a low IAP exercise routine. More research is needed to determine the long term effects of Pilates exercise on post-surgical exercise rehabilitation and pelvic floor health. PMID:25672647

Multi-scale landscape factors influencing stream water quality in the state of Oregon.

PubMed

Nash, Maliha S; Heggem, Daniel T; Ebert, Donald; Wade, Timothy G; Hall, Robert K

2009-09-01

Enterococci bacteria are used to indicate the presence of human and/or animal fecal materials in surface water. In addition to human influences on the quality of surface water, a cattle grazing is a widespread and persistent ecological stressor in the Western United States. Cattle may affect surface water quality directly by depositing nutrients and bacteria, and indirectly by damaging stream banks or removing vegetation cover, which may lead to increased sediment loads. This study used the State of Oregon surface water data to determine the likelihood of animal pathogen presence using enterococci and analyzed the spatial distribution and relationship of biotic (enterococci) and abiotic (nitrogen and phosphorous) surface water constituents to landscape metrics and others (e.g. human use, percent riparian cover, natural covers, grazing, etc.). We used a grazing potential index (GPI) based on proximity to water, land ownership and forage availability. Mean and variability of GPI, forage availability, stream density and length, and landscape metrics were related to enterococci and many forms of nitrogen and phosphorous in standard and logistic regression models. The GPI did not have a significant role in the models, but forage related variables had significant contribution. Urban land use within stream reach was the main driving factor when exceeding the threshold (> or =35 cfu/100 ml), agriculture was the driving force in elevating enterococci in sites where enterococci concentration was <35 cfu/100 ml. Landscape metrics related to amount of agriculture, wetlands and urban all contributed to increasing nutrients in surface water but at different scales. The probability of having sites with concentrations of enterococci above the threshold was much lower in areas of natural land cover and much higher in areas with higher urban land use within 60 m of stream. A 1% increase in natural land cover was associated with a 12% decrease in the predicted odds of having a site exceeding the threshold. Opposite to natural land cover, a one unit change in each of manmade barren and urban land use led to an increase of the likelihood of exceeding the threshold by 73%, and 11%, respectively. Change in urban land use had a higher influence on the likelihood of a site exceeding the threshold than that of natural land cover.

Aquatic toxicity of airfield-pavement deicer materials and implications for airport runoff

USGS Publications Warehouse

Corsi, S.R.; Geis, S.W.; Bowman, G.; Failey, G.G.; Rutter, T.D.

2009-01-01

Concentrations of airfield-pavement deicer materials (PDM) in a study of airport runoff often exceeded levels of concern regarding aquatic toxicity. Toxicity tests on Vibrio fischeri, Pimephales promelas, Ceriodaphnia dubia, and Pseudokirchneriella subcapitata (commonly known as Selenastrum capricornutum) were performed with potassium acetate (K-Ac) PDM, sodium formate (Na-For) PDM, and with freezing- point depressants (K-Ac and Na-For). Results indicate that toxicity in PDM is driven by the freezing-point depressants in all tests except the Vibrio fisheri test for Na-For PDM which is influenced by an additive. Acute toxicity end points for different organisms ranged from 298 to 6560 mg/L (as acetate) for K-Ac PDM and from 1780 to 4130 mg/L (as formate) for Na- For PDM. Chronic toxicity end points ranged from 19.9 to 336 mg/L (as acetate) for K-Ac PDM and from 584 to 1670 mg/L (as formate) for Na-For PDM. Sample results from outfalls at General Mitchell International Airport in Milwaukee, Wl (GMIA) indicated that 40% of samples had concentrations greater than the aquatic-life benchmark for K-Ac PDM. K-Ac has replaced urea during the 1990s as the most widely used PDM at GMIA and in the United States. Results of ammonia samples from airport outfalls during periods when urea-based PDM was used at GMIA indicated that41% of samples had concentrations exceeding the U.S. Environmental Protection Agency (USEPA) 1 -h water-quality criterion. The USEPA 1-h water-quality criterion for chloride was exceeded in 68% of samples collected in the receiving stream, a result of road-salt runoff from urban influence near the airport. Results demonstrate that PDM must be considered to comprehensively evaluate the impact of chemical deicers on aquatic toxicity in water containing airport runoff. ?? 2009 American Chemical Society.

Refinement of a thermal threshold probe to prevent burns.

PubMed

Dixon, M J; Taylor, P M; Slingsby, L C; Murrell, J C

2016-02-01

Thermal threshold testing is commonly used for pain research. The stimulus may cause burning and merits prevention. Thermal probe modifications hypothesized to reduce burning were evaluated for practicality and effect. Studies were conducted on two humans and eight cats. Unmodified probe 0 was tested on two humans and promising modifications were also evaluated on cats. Probe 1 incorporated rapid cooling after threshold was reached: probe 1a used a Peltier system and probe 1b used water cooling. Probe 2 released skin contact immediately after threshold. Probe 3 (developed in the light of evidence of 'hot spots' in probe 0) incorporated reduced thermal mass and even heating across the skin contact area. Human skin was heated to 48℃ (6℃ above threshold) and the resulting burn was evaluated using area of injury and a simple descriptive scale (SDS). Probe 1a cooled the skin but required further heat dissipation, excessive power, was not 'fail-safe' and was inappropriate for animal mounting. Probe 1b caused less damage than no cooling (27 ± 13 and 38 ± 11 mm(2) respectively, P = 0.0266; median SDS 1.5 and 4 respectively, P = 0.0317) but was cumbersome. Probe 2 was unwieldy and was not evaluated further. Probe 3 produced even heating without blistering in humans. With probe 3 in cats, after opioid treatment, thermal threshold reached cut-out (55℃) on 24 occasions, exceeded 50℃ in a further 32 tests and exceeded 48℃ in the remainder. No skin damage was evident immediately after testing and mild hyperaemia in three cats at 2-3 days resolved rapidly. Probe 3 appeared to be suitable for thermal threshold testing. © The Author(s) 2015.

Novel threshold pressure sensors based on nonlinear dynamics of MEMS resonators

NASA Astrophysics Data System (ADS)

Hasan, Mohammad H.; Alsaleem, Fadi M.; Ouakad, Hassen M.

2018-06-01

Triggering an alarm in a car for low air-pressure in the tire or tripping an HVAC compressor if the refrigerant pressure is lower than a threshold value are examples for applications where measuring the amount of pressure is not as important as determining if the pressure has exceeded a threshold value for an action to occur. Unfortunately, current technology still relies on analog pressure sensors to perform this functionality by adding a complex interface (extra circuitry, controllers, and/or decision units). In this paper, we demonstrate two new smart tunable-threshold pressure switch concepts that can reduce the complexity of a threshold pressure sensor. The first concept is based on the nonlinear subharmonic resonance of a straight double cantilever microbeam with a proof mass and the other concept is based on the snap-through bi-stability of a clamped-clamped MEMS shallow arch. In both designs, the sensor operation concept is simple. Any actuation performed at a certain pressure lower than a threshold value will activate a nonlinear dynamic behavior (subharmonic resonance or snap-through bi-stability) yielding a large output that would be interpreted as a logic value of ONE, or ON. Once the pressure exceeds the threshold value, the nonlinear response ceases to exist, yielding a small output that would be interpreted as a logic value of ZERO, or OFF. A lumped, single degree of freedom model for the double cantilever beam, that is validated using experimental data, and a continuous beam model for the arch beam, are used to simulate the operation range of the proposed sensors by identifying the relationship between the excitation signal and the critical cut-off pressure.

A hydroclimatic threshold for landslide initiation on the North Shore Mountains of Vancouver, British Columbia

NASA Astrophysics Data System (ADS)

Jakob, Matthias; Weatherly, Hamish

2003-09-01

Landslides triggered by rainfall are the cause of thousands of deaths worldwide every year. One possible approach to limit the socioeconomic consequences of such events is the development of climatic thresholds for landslide initiation. In this paper, we propose a method that incorporates antecedent rainfall and streamflow data to develop a landslide initiation threshold for the North Shore Mountains of Vancouver, British Columbia. Hydroclimatic data were gathered for 18 storms that triggered landslides and 18 storms that did not. Discriminant function analysis separated the landslide-triggering storms from those storms that did not trigger landslides and selected the most meaningful variables that allow this separation. Discriminant functions were also developed for the landslide-triggering and nonlandslide-triggering storms. The difference of the discriminant scores, ΔCS, for both groups is a measure of landslide susceptibility during a storm. The variables identified that optimize the separation of the two storm groups are 4-week rainfall prior to a significant storm, 6-h rainfall during a storm, and the number of hours 1 m 3/s discharge was exceeded at Mackay Creek during a storm. Three thresholds were identified. The Landslide Warning Threshold (LWT) is reached when ΔCS is -1. The Conditional Landslide Initiation Threshold (CTL I) is reached when ΔCS is zero, and it implies that landslides are likely if 4 mm/h rainfall intensity is exceeded at which point the Imminent Landslide Initiation Threshold (ITL I) is reached. The LWT allows time for the issuance of a landslide advisory and to move personnel out of hazardous areas. The methodology proposed in this paper can be transferred to other regions worldwide where type and quality of data are appropriate for this type of analysis.

Validation of spatial variability in downscaling results from the VALUE perfect predictor experiment

NASA Astrophysics Data System (ADS)

Widmann, Martin; Bedia, Joaquin; Gutiérrez, Jose Manuel; Maraun, Douglas; Huth, Radan; Fischer, Andreas; Keller, Denise; Hertig, Elke; Vrac, Mathieu; Wibig, Joanna; Pagé, Christian; Cardoso, Rita M.; Soares, Pedro MM; Bosshard, Thomas; Casado, Maria Jesus; Ramos, Petra

2016-04-01

VALUE is an open European network to validate and compare downscaling methods for climate change research. Within VALUE a systematic validation framework to enable the assessment and comparison of both dynamical and statistical downscaling methods has been developed. In the first validation experiment the downscaling methods are validated in a setup with perfect predictors taken from the ERA-interim reanalysis for the period 1997 - 2008. This allows to investigate the isolated skill of downscaling methods without further error contributions from the large-scale predictors. One aspect of the validation is the representation of spatial variability. As part of the VALUE validation we have compared various properties of the spatial variability of downscaled daily temperature and precipitation with the corresponding properties in observations. We have used two test validation datasets, one European-wide set of 86 stations, and one higher-density network of 50 stations in Germany. Here we present results based on three approaches, namely the analysis of i.) correlation matrices, ii.) pairwise joint threshold exceedances, and iii.) regions of similar variability. We summarise the information contained in correlation matrices by calculating the dependence of the correlations on distance and deriving decorrelation lengths, as well as by determining the independent degrees of freedom. Probabilities for joint threshold exceedances and (where appropriate) non-exceedances are calculated for various user-relevant thresholds related for instance to extreme precipitation or frost and heat days. The dependence of these probabilities on distance is again characterised by calculating typical length scales that separate dependent from independent exceedances. Regionalisation is based on rotated Principal Component Analysis. The results indicate which downscaling methods are preferable if the dependency of variability at different locations is relevant for the user.

An Investigation of Landing-Contact Conditions for a Large Turbojet Transport During Routine Daylight Operations

NASA Technical Reports Server (NTRS)

Stickle, Joseph W.; Silsby, Norman S.

1960-01-01

An investigation has been made by the NASA to obtain statistical measurements of landing-contact conditions for a large turbojet transport in commercial airline operations. The investigation was conducted at the Los Angeles International Airport in Los Angeles, California. Measurements were taken photographically during routine daylight operations. The quantities determined were vertical velocity, horizontal velocity, rolling velocity, bank angle, and distance from runway threshold, just prior to ground contact. The results indicated that the mean vertical velocity for the turbojet-transport landings was 1.62 feet per second and that 1 landing out of 100 would be expected to equal or exceed about 4.0 feet per second. The mean airspeed at contact was 132.0 knots, with 1 landing in 100 likely to equal or exceed about 153.0 knots. The mean rolling velocity was about 1.6 deg per second. One lending in 100 would probably equal or exceed a rolling velocity of about 4.0 deg. per second in the direction of the first wheel to touch. The mean bank angle for the turbojet transports was 1.04 deg, and right and left angles of bank were about evenly divided. One lending in 100 would be likely to equal or exceed a bank angle of about 3.5 deg. The mean value of distance to touchdown from the runway threshold was 1,560 feet. One lending in 100 would be expected to touchdown at or beyond about 2,700 feet from the runway threshold. The mean values for vertical velocity, airspeed, and distance t o touch-down for the turbojet transports were somewhat higher than those found previously for piston-engine transports. No significant differences were found for values of rolling velocity and bank angle.

The Threshold of Toxicological Concern for prenatal developmental toxicity in rats and rabbits

PubMed Central

van Ravenzwaay, B.; Jiang, X.; Luechtefeld, T.; Hartung, T.

2018-01-01

The Threshold Toxicological Concern (TTC) is based on the concept that in absence of experimental data reasonable assurance of safety can be given if exposure is sufficiently low. Using the REACH database the low 5th percentile of the NO(A)EL distribution, for prenatal developmental toxicity (OECD guideline 414) was determined. For rats, (434 NO(A)ELs values) for maternal toxicity, this value was 10 mg/kg-bw/day. For developmental toxicity (469 NO(A)ELs): 13 mg/kg-bw/day. For rabbits, (100 NO(A)ELs), the value for maternal toxicity was 4 mg/kg-bw/day, for developmental toxicity, (112 NO(A)EL values): 10 mg/kg-bw/day. The maternal organism may thus be slightly more sensitive than the fetus. Combining REACH- (industrial chemicals) and published BASF-data (mostly agrochemicals), 537 unique compounds with NO(A)EL values for developmental toxicity in rats and 150 in rabbits were evaluated. The low 5th percentile NO(A)EL for developmental toxicity in rats was 10 mg/kg-bw/day and 9.5 mg/kg-bw/day for rabbits. Using an assessment factor of 100, a TTC value for developmental toxicity of 100 µg/kg-bw/day for rats and 95 µg/kg-bw/day for rabbits is calculated. These values could serve as guidance whether or not to perform an animal experiment, if exposure is sufficiently low. In emergency situations this value may be useful for a first tier risk assessment. PMID:28645885

Spatiotemporal Characterization of Ambient PM2.5 Concentrations in Shandong Province (China).

PubMed

Yang, Yong; Christakos, George

2015-11-17

China experiences severe particulate matter (PM) pollution problems closely linked to its rapid economic growth. Advancing the understanding and characterization of spatiotemporal air pollution distribution is an area where improved quantitative methods are of great benefit to risk assessment and environmental policy. This work uses the Bayesian maximum entropy (BME) method to assess the space-time variability of PM2.5 concentrations and predict their distribution in the Shandong province, China. Daily PM2.5 concentrations obtained at air quality monitoring sites during 2014 were used. On the basis of the space-time PM2.5 distributions generated by BME, we performed three kinds of querying analysis to reveal the main distribution features. The results showed that the entire region of interest is seriously polluted (BME maps identified heavy pollution clusters during 2014). Quantitative characterization of pollution severity included both pollution level and duration. The number of days during which regional PM2.5 exceeded 75, 115, 150, and 250 μg m(-3) varied: 43-253, 13-128, 4-66, and 0-15 days, respectively. The PM2.5 pattern exhibited an increasing trend from east to west, with the western part of Shandong being a heavily polluted area (PM2.5 exceeded 150 μg m(-3) during long time periods). Pollution was much more serious during winter than during other seasons. Site indicators of PM2.5 pollution intensity and space-time variation were used to assess regional uncertainties and risks with their interpretation depending on the pollutant threshold. The observed PM2.5 concentrations exceeding a specified threshold increased almost linearly with increasing threshold value, whereas the relative probability of excess pollution decreased sharply with increasing threshold.

Interpretation of urinary concentrations of pseudoephedrine and its metabolite cathine in relation to doping control.

PubMed

Deventer, K; Van Eenoo, P; Baele, G; Pozo, O J; Van Thuyne, W; Delbeke, F T

2009-05-01

Until the end of 2003 a urinary concentration of pseudoephedrine exceeding 25 microg/mL was regarded as a doping violation by the World Anti-Doping Agency. Since its removal from the prohibited list in 2004 the number of urine samples in which pseudoephedrine was detected in our laboratory increased substantially. Analysis of 116 in-competition samples containing pseudoephedrine in 2007 and 2008, revealed that 66% of these samples had a concentration of pseudoephedrine above 25 microg/mL. This corresponded to 1.4% of all tested in competition samples in that period. In the period 2001-2003 only 0.18% of all analysed in competition samples contained more than 25 microg/mL. Statistical comparison of the two periods showed that after the removal of pseudoephedrine from the list its use increased significantly. Of the individual sports compared between the two periods, only cycling is shown to yield a significant increase.Analysis of excretion urine samples after administration of a therapeutic daily dose (240 mg pseudoephedrine) in one administration showed that the threshold of 25 microg/mL can be exceeded. The same samples were also analysed for cathine, which has currently a threshold of 5 microg/mL on the prohibited list. The maximum urinary concentration of cathine also exceeded the threshold for some volunteers. Comparison of the measured cathine and pseudoephedrine concentrations only indicated a poor correlation between them. Hence, cathine is not a good indicator to control pseudopehedrine intake. To control the (ab)use of ephedrines in sports it is recommended that WADA reintroduce a threshold for pseudoephedrine. Copyright 2009 John Wiley & Sons, Ltd.

77 FR 23135 - 2,4-D; Order Denying NRDC's Petition To Revoke Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-18

... cannot be determined (``non-threshold effects''). Because EPA identified only threshold effect risks for... uncertainty or safety factors \\1\\ in conjunction with experimental toxicity data in assessing risk to humans... difference in sensitivity between humans and experimental animals (i.e., inter-species sensitivity) and...

40 CFR 372.27 - Alternate threshold and certification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 28 2014-07-01 2014-07-01 false Alternate threshold and certification. 372.27 Section 372.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.2...

40 CFR 372.95 - Alternate threshold certification and instructions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 29 2012-07-01 2012-07-01 false Alternate threshold certification and instructions. 372.95 Section 372.95 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Forms and...

40 CFR 372.27 - Alternate threshold and certification.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 29 2012-07-01 2012-07-01 false Alternate threshold and certification. 372.27 Section 372.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.2...

40 CFR 372.27 - Alternate threshold and certification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 27 2010-07-01 2010-07-01 false Alternate threshold and certification. 372.27 Section 372.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.2...

40 CFR 372.95 - Alternate threshold certification and instructions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 28 2014-07-01 2014-07-01 false Alternate threshold certification and instructions. 372.95 Section 372.95 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Forms and...

40 CFR 372.27 - Alternate threshold and certification.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 28 2011-07-01 2011-07-01 false Alternate threshold and certification. 372.27 Section 372.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Reporting Requirements § 372.2...

40 CFR 372.95 - Alternate threshold certification and instructions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 28 2011-07-01 2011-07-01 false Alternate threshold certification and instructions. 372.95 Section 372.95 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Forms and...

40 CFR 372.95 - Alternate threshold certification and instructions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 27 2010-07-01 2010-07-01 false Alternate threshold certification and instructions. 372.95 Section 372.95 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND, EMERGENCY PLANNING, AND COMMUNITY RIGHT-TO-KNOW PROGRAMS TOXIC CHEMICAL RELEASE REPORTING: COMMUNITY RIGHT-TO-KNOW Forms and...

Seismic switch for strong motion measurement

DOEpatents

Harben, Philip E.; Rodgers, Peter W.; Ewert, Daniel W.

1995-01-01

A seismic switching device that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period.

Seismic switch for strong motion measurement

DOEpatents

Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

1995-05-30

A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

Article surveillance magnetic marker having an hysteresis loop with large Barkhausen discontinuities

DOEpatents

Humphrey, Floyd B.

1987-01-01

A marker for an electronic article surveillance system is disclosed comprising a body of magnetic material with retained stress and having a magnetic hysteresis loop with a large Barkhausen discontinuity such that, upon exposure of the marker to an external magnetic field whose field strength in the direction opposing the instantaneous magnetic polarization of the marker exceeds a predetermined threshold value, there results a regenerative reversal of the magnetic polarization of the marker. An electronic article surveillance system and a method utilizing the marker are also disclosed. Exciting the marker with a low frequency and low field strength, so long as the field strength exceeds the low threshold level for the marker, causes a regenerative reversal of magnetic polarity generating a harmonically rich pulse that is readily detected and easily distinguished.

Macro-invertebrate decline in surface water polluted with imidacloprid: a rebuttal and some new analyses.

PubMed

Vijver, Martina G; van den Brink, Paul J

2014-01-01

Imidacloprid, the largest selling insecticide in the world, has received particular attention from scientists, policymakers and industries due to its potential toxicity to bees and aquatic organisms. The decline of aquatic macro-invertebrates due to imidacloprid concentrations in the Dutch surface waters was hypothesised in a recent paper by Van Dijk, Van Staalduinen and Van der Sluijs (PLOS ONE, May 2013). Although we do not disagree with imidacloprid's inherent toxicity to aquatic organisms, we have fundamental concerns regarding the way the data were analysed and interpreted. Here, we demonstrate that the underlying toxicity of imidacloprid in the field situation cannot be understood except in the context of other co-occurring pesticides. Although we agree with Van Dijk and co-workers that effects of imidacloprid can emerge between 13 and 67 ng/L we use a different line of evidence. We present an alternative approach to link imidacloprid concentrations and biological data. We analysed the national set of chemical monitoring data of the year 2009 to estimate the relative contribution of imidacloprid compared to other pesticides in relation to environmental quality target and chronic ecotoxicity threshold exceedances. Moreover, we assessed the relative impact of imidacloprid on the pesticide-induced potential affected fractions of the aquatic communities. We conclude that by choosing to test a starting hypothesis using insufficient data on chemistry and biology that are difficult to link, and by ignoring potential collinear effects of other pesticides present in Dutch surface waters Van Dijk and co-workers do not provide direct evidence that reduced taxon richness and abundance of macroinvertebrates can be attributed to the presence of imidacloprid only. Using a different line of evidence we expect ecological effects of imidacloprid at some of the exposure profiles measured in 2009 in the surface waters of the Netherlands.

Leaching of CCA-treated wood: implications for waste disposal.

PubMed

Townsend, Timothy; Tolaymat, Thabet; Solo-Gabriele, Helena; Dubey, Brajesh; Stook, Kristin; Wadanambi, Lakmini

2004-10-18

Leaching of arsenic, chromium, and copper from chromated copper arsenate (CCA)-treated wood poses possible environmental risk when disposed. Samples of un-weathered CCA-treated wood were tested using a variety of the US regulatory leaching procedures, including the toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), extraction procedure toxicity method (EPTOX), waste extraction test (WET), multiple extraction procedure (MEP), and modifications of these procedures which utilized actual MSW landfill leachates, a construction and demolition (C and D) debris leachate, and a concrete enhanced leachate. Additional experiments were conducted to assess factors affecting leaching, such as particle size, pH, and leaching contact time. Results from the regulatory leaching tests provided similar results with the exception of the WET, which extracted greater quantities of metals. Experiments conducted using actual MSW leachate, C and D debris leachate, and concrete enhanced leachate provided results that were within the same order of magnitude as results obtained from TCLP, SPLP, and EPTOX. Eleven of 13 samples of CCA-treated dimensional lumber exceeded the US EPA's toxicity characteristic (TC) threshold for arsenic (5 mg/L). If un-weathered arsenic-treated wood were not otherwise excluded from the definition of hazardous waste, it frequently would require management as such. When extracted with simulated rainwater (SPLP), 9 of the 13 samples leached arsenic at concentrations above 5 mg/L. Metal leachability tended to increase with decreasing particle size and at pH extremes. All three metals leached above the drinking water standards thus possibly posing a potential risk to groundwater. Arsenic is a major concern from a disposal point of view with respect to ground water quality.

Detection and Measurement of Unhealthy, Environment-Derived Aerosol Materials in an Emergency Department.

PubMed

Choi, Bryan Y; Kobayashi, Leo; Pathania, Shivany; Miller, Courtney B; Locke, Emma R; Stearns, Branden C; Hudepohl, Nathan J; Patefield, Scott S; Suner, Selim; Williams, Kenneth A; Machan, Jason T; Jay, Gregory D

2015-01-01

To measure unhealthy aerosol materials in an Emergency Department (ED) and identify their sources for mitigation efforts. Based on pilot findings of elevated ED particulate matter (PM) levels, investigators hypothesized that unhealthy aerosol materials derive from exogenous (vehicular) sources at ambulance receiving entrances. The Aerosol Environmental Toxicity in Healthcare-related Exposure and Risk program was conducted as an observational study. Calibrated sensors monitored PM and toxic gases at Ambulance Triage Exterior (ATE), Ambulance Triage Desk (ATD), and control Public Triage Desk (PTD) on a 3/3/3-day cycle. Cassette sampling characterized PM; meteorological and ambulance traffic data were logged. Descriptive and multiple linear regression analyses assessed for interactions between aerosol material levels, location, temporal variables, ambulance activity, and meteorological factors. Sensors acquired 93,682 PM0.3, 90,250 PM2.5, and 93,768 PM5 measurements over 366 days to generate a data set representing at least 85.6% of planned measurements. PM0.3, PM2.5, and PM5 mean counts were lowest in PTD; 56%, 224%, and 223% higher in ATD; and 996%, 200%, and 63% higher in ATE, respectively (all p < .001). Qualitative analyses showed similar PM compositions in ATD and ATE. On multiple linear regression analysis, PM0.3 counts correlated primarily with location; PM2.5 and PM5 counts correlated most strongly with location and ambulance presence. PM < 2.5 and toxic gas concentrations at ATD and PTD patient care areas did not exceed hazard levels; PM0.3 counts did not have formal safety thresholds for comparison. Higher levels of PM were linked with ED ambulance areas, although their health impact is unclear. © The Author(s) 2015.

Investigation of relationship between 2,3-butanediol toxicity and production during growth of Paenibacillus polymyxa.

PubMed

Okonkwo, Christopher Chukwudi; Ujor, Victor; Ezeji, Thaddeus Chukwuemeka

2017-01-25

Understanding the capacity of Paenibacillus polymyxa DSM 365 to tolerate increasing concentrations of 2,3-butanediol (2,3-BD) is critical to engineering a 2,3-BD-overproducing strain. Hence, we investigated the response of P. polymyxa to high 2,3-BD concentrations. In fed-batch cultures (6-L bioreactor) 2,3-BD was accumulated to a maximum concentration of 47g/L despite the presence of residual 13g/L glucose in the medium. Concomitantly, accumulation of acetoin, the precursor of 2,3-BD increased after maximum 2,3-BD concentration was reached, suggesting that 2,3-BD was reconverted to acetoin after the concentration tolerance threshold of 2,3-BD was exceeded. Cultures of P. polymyxa were then challenged with levo-2,3-BD (20, 40 and 60g/L) at 0h in a glucose medium, and a concentration dependent growth inhibition response to levo-2,3-BD was observed. The growth of P. polymyxa was completely inhibited by 60g/L levo-2,3-BD. Furthermore, P. polymyxa was challenged with incremental 2,3-BD concentrations (20, 40 and 60g/L at 12, 24 and 36h, respectively) to mimic 2,3-BD accumulation during fermentation. Interestingly, 2,3-BD was reconverted to acetoin when its concentration reached 60g/L, possibly to alleviate 2,3-BD toxicity. Collectively, our findings indicate that 2,3-BD-mediated toxicity is a major metabolic impediment to 2,3-BD overproduction, thus, making it an important metabolic engineering target towards rational design of a 2,3-BD-overproducing strain. Copyright © 2016 Elsevier B.V. All rights reserved.

The activity of the pyrrole insecticide chlorfenapyr in mosquito bioassay: towards a more rational testing and screening of non-neurotoxic insecticides for malaria vector control.

PubMed

Oxborough, Richard M; N'Guessan, Raphael; Jones, Rebecca; Kitau, Jovin; Ngufor, Corine; Malone, David; Mosha, Franklin W; Rowland, Mark W

2015-03-24

The rapid selection of pyrethroid resistance throughout sub-Saharan Africa is a serious threat to malaria vector control. Chlorfenapyr is a pyrrole insecticide which shows no cross resistance to insecticide classes normally used for vector control and is effective on mosquito nets under experimental hut conditions. Unlike neurotoxic insecticides, chlorfenapyr owes its toxicity to disruption of metabolic pathways in mitochondria that enable cellular respiration. A series of experiments explored whether standard World Health Organization (WHO) guidelines for evaluation of long-lasting insecticidal nets, developed through testing of pyrethroid insecticides, are suitable for evaluation of non-neurotoxic insecticides. The efficacy of WHO recommended cone, cylinder and tunnel tests was compared for pyrethroids and chlorfenapyr. To establish bioassay exposure times predictive of insecticide-treated net (ITN) efficacy in experimental hut trials, standard three-minute bioassays of pyrethroid and chlorfenapyr ITNs were compared with longer exposures. Mosquito behaviour and response to chlorfenapyr ITN in bioassays conducted at night were compared to day and across a range of temperatures representative of highland and lowland transmission. Standard three-minute bioassay of chlorfenapyr produced extremely low levels of mortality compared to pyrethroids. Thirty-minute day-time bioassay produced mortality closer to hut efficacy of chlorfenapyr ITN but still fell short of the WHO threshold. Overnight tunnel test with chlorfenapyr produced 100% mortality and exceeded the WHO threshold of 80%. The endogenous circadian activity rhythm of anophelines results in inactivity by day and raised metabolism and flight activity by night. A model which explains improved toxicity of chlorfenapyr ITN when tested at night, and during the day at higher ambient temperature, is that activation of chlorfenapyr and disruption of respiratory pathways is enhanced when the insect is more metabolically and behaviourally active. Testing according to current WHO guidelines is not suitable for certain types of non-neurotoxic insecticide which, although highly effective in field trials, would be overlooked at the screening stage of evaluation through bioassay. Testing methods must be tailored to the characteristics and mode of action of each insecticide class. The WHO tunnel test on night-active anophelines is the most reliable bioassay for identifying the toxicity of novel insecticides.

Monitoring and modeling to predict Escherichia coli at Presque Isle Beach 2, City of Erie, Erie County, Pennsylvania

USGS Publications Warehouse

Zimmerman, Tammy M.

2006-01-01

The Lake Erie shoreline in Pennsylvania spans nearly 40 miles and is a valuable recreational resource for Erie County. Nearly 7 miles of the Lake Erie shoreline lies within Presque Isle State Park in Erie, Pa. Concentrations of Escherichia coli (E. coli) bacteria at permitted Presque Isle beaches occasionally exceed the single-sample bathing-water standard, resulting in unsafe swimming conditions and closure of the beaches. E. coli concentrations and other water-quality and environmental data collected at Presque Isle Beach 2 during the 2004 and 2005 recreational seasons were used to develop models using tobit regression analyses to predict E. coli concentrations. All variables statistically related to E. coli concentrations were included in the initial regression analyses, and after several iterations, only those explanatory variables that made the models significantly better at predicting E. coli concentrations were included in the final models. Regression models were developed using data from 2004, 2005, and the combined 2-year dataset. Variables in the 2004 model and the combined 2004-2005 model were log10 turbidity, rain weight, wave height (calculated), and wind direction. Variables in the 2005 model were log10 turbidity and wind direction. Explanatory variables not included in the final models were water temperature, streamflow, wind speed, and current speed; model results indicated these variables did not meet significance criteria at the 95-percent confidence level (probabilities were greater than 0.05). The predicted E. coli concentrations produced by the models were used to develop probabilities that concentrations would exceed the single-sample bathing-water standard for E. coli of 235 colonies per 100 milliliters. Analysis of the exceedence probabilities helped determine a threshold probability for each model, chosen such that the correct number of exceedences and nonexceedences was maximized and the number of false positives and false negatives was minimized. Future samples with computed exceedence probabilities higher than the selected threshold probability, as determined by the model, will likely exceed the E. coli standard and a beach advisory or closing may need to be issued; computed exceedence probabilities lower than the threshold probability will likely indicate the standard will not be exceeded. Additional data collected each year can be used to test and possibly improve the model. This study will aid beach managers in more rapidly determining when waters are not safe for recreational use and, subsequently, when to issue beach advisories or closings.

Weight-of-evidence approach in assessment of ecotoxicological risks of acid sulphate soils in the Baltic Sea river estuaries.

PubMed

Wallin, Jaana; Karjalainen, Anna K; Schultz, Eija; Järvistö, Johanna; Leppänen, Matti; Vuori, Kari-Matti

2015-03-01

Acidity and leaching of metals from acid sulphate soils (ASSs) impair the water quality of receiving surface waters. The largest ASS areas in Europe are found in the coasts of the northern Baltic Sea. We used weight-of-evidence (WoE) approach to assess potential risks in 14 estuary sites affected by ASS in the Gulf of Finland, northern Baltic Sea. The assessment was based on exposure and effect profiles utilizing sediment and water metal concentrations and concurrent pH variation, sediment toxicity tests using the luminescent bacterium Vibrio fischeri and the midge Chironomus riparius, and the ecological status of benthic macroinvertebrate communities. Sediment metal concentrations were compared to national sediment quality criteria/guidelines, and water metal concentrations to environmental quality standards (EQSs). Hazard quotients (HQs) were established for maximum aluminium, cadmium and zinc concentrations at low pH based on applicable US EPA toxicity database. Sediment metal concentrations were clearly elevated in most of the studied estuaries. The EQS of cadmium (0.1 μg/l) was exceeded in 3 estuaries out of 14. The pH-minima were below the national threshold value (5.5) between good and satisfactory water quality in 10 estuaries. V. fischeri bioluminescence indicated toxicity of the sediments but toxic response was not observed in the C. riparius emergence test. Benthic invertebrate communities were deteriorated in 6 out of 14 sites based on the benthic invertebrate quality index. The overall ecotoxicological risk was assessed as low in five, moderate in three and high in five of the estuary sites. The risk assessment utilizing the WoE approach indicated that harmful effects of ASSs are likely to occur in the Baltic Sea river estuaries located at the ASS hotspot area. Copyright © 2014 Elsevier B.V. All rights reserved.

Increased seizure susceptibility and other toxicity symptoms following acute sulforaphane treatment in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Socała, Katarzyna, E-mail: ksocala@op.pl

Activation of Nrf2 with sulforaphane has recently gained attention as a new therapeutic approach in the treatment of many diseases, including epilepsy. As a plant-derived compound, sulforaphane is considered to be safe and well-tolerated. It is widely consumed, also by patients suffering from seizure and taking antiepileptic drugs, but no toxicity profile of sulforaphane exists. Since many natural remedies and dietary supplements may increase seizure risk and potentially interact with antiepileptic drugs, the aim of our study was to investigate the acute effects of sulforaphane on seizure thresholds and activity of some first- and second-generation antiepileptic drugs in mice. Inmore » addition, some preliminary toxicity profile of sulforaphane in mice after intraperitoneal injection was evaluated. The LD{sub 50} value of sulforaphane in mice was estimated at 212.67 mg/kg, while the TD{sub 50} value – at 191.58 mg/kg. In seizure tests, sulforaphane at the highest dose tested (200 mg/kg) significantly decreased the thresholds for the onset of the first myoclonic twitch and generalized clonic seizure in the iv PTZ test as well as the threshold for the 6 Hz-induced psychomotor seizure. At doses of 10–200 mg/kg, sulforaphane did not affect the threshold for the iv PTZ-induced forelimb tonus or the threshold for maximal electroshock-induced hindlimb tonus. Interestingly, sulforaphane (at 100 mg/kg) potentiated the anticonvulsant efficacy of carbamazepine in the maximal electroshock seizure test. This interaction could have been pharmacokinetic in nature, as sulforaphane increased concentrations of carbamazepine in both serum and brain tissue. The toxicity study showed that high doses of sulforaphane produced marked sedation (at 150–300 mg/kg), hypothermia (at 150–300 mg/kg), impairment of motor coordination (at 200–300 mg/kg), decrease in skeletal muscle strength (at 250–300 mg/kg), and deaths (at 200–300 mg/kg). Moreover, blood analysis showed leucopenia in mice injected with sulforaphane at 200 mg/kg. In conclusion, since sulforaphane was proconvulsant at a toxic dose, the safety profile and the risk-to-benefit ratio of sulforaphane usage in epileptic patients should be further evaluated. - Highlights: • Sulforaphane, an Nrf2 activator, is proconvulsant at toxic doses in mice. • Sulforaphane at 100 mg/kg produces a pharmacokinetic interaction with carbamazepine. • Sulforaphane has an LD{sub 50} of 212.67 mg/kg in mice (after ip administration). • The risk-to-benefit ratio of sulforaphane needs further evaluation.« less

32 CFR 32.44 - Procurement procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... acceptable characteristics or minimum acceptable standards. (iv) The specific features of “brand name or... expected to exceed the simplified acquisition threshold, specifies a “brand name” product. (4) The proposed...

Importance of the Pre-Industrial Baseline in Determining the Likelihood of Exceeding the Paris Limits

NASA Astrophysics Data System (ADS)

Mann, M. E.; Schurer, A. P.; Hawkins, E.; Tett, S. F.; Hegerl, G. C.

2017-12-01

During the Paris Conference in 2015, nations of the world strengthened the United NationsFramework Convention on Climate Change by agreeing to holding "the increase in the globalaverage temperature to well below 2°C above pre-industrial levels and pursuing efforts to limitthe temperature increase to 1.5°C. However, "pre-industrial" was not defined. Here weinvestigate the implications of different choices of the pre-industrial baseline on the likelihood ofexceeding these two temperature thresholds. We find that for the strongest mitigation scenarioRCP2.6 and a medium scenario RCP4.5 the probability of exceeding the thresholds and timingof exceedance is highly dependent on the pre-industrial baseline, for example the probability ofcrossing 1.5°C by the end of the century under RCP2.6, varies from 61% to 88% depending onhow the baseline is defined. In contrast, in the scenario with no mitigation, RCP8.5, boththresholds will almost certainly be exceeded by the middle of the century with the definition ofthe pre-industrial baseline of less importance. Allowable carbon emissions for thresholdstabilisation are similarly highly dependent on the pre-industrial baseline. For stabilisation at2°C, allowable emissions decrease by as much as 40% when earlier than 19th century climatesare considered as a baseline.

Critical thresholds in sea lice epidemics: evidence, sensitivity and subcritical estimation

PubMed Central

Frazer, L. Neil; Morton, Alexandra; Krkošek, Martin

2012-01-01

Host density thresholds are a fundamental component of the population dynamics of pathogens, but empirical evidence and estimates are lacking. We studied host density thresholds in the dynamics of ectoparasitic sea lice (Lepeophtheirus salmonis) on salmon farms. Empirical examples include a 1994 epidemic in Atlantic Canada and a 2001 epidemic in Pacific Canada. A mathematical model suggests dynamics of lice are governed by a stable endemic equilibrium until the critical host density threshold drops owing to environmental change, or is exceeded by stocking, causing epidemics that require rapid harvest or treatment. Sensitivity analysis of the critical threshold suggests variation in dependence on biotic parameters and high sensitivity to temperature and salinity. We provide a method for estimating the critical threshold from parasite abundances at subcritical host densities and estimate the critical threshold and transmission coefficient for the two epidemics. Host density thresholds may be a fundamental component of disease dynamics in coastal seas where salmon farming occurs. PMID:22217721

Surface ablation of aluminum and silicon by ultrashort laser pulses of variable width

NASA Astrophysics Data System (ADS)

Zayarny, D. A.; Ionin, A. A.; Kudryashov, S. I.; Makarov, S. V.; Kuchmizhak, A. A.; Vitrik, O. B.; Kulchin, Yu. N.

2016-06-01

Single-shot thresholds of surface ablation of aluminum and silicon via spallative ablation by infrared (IR) and visible ultrashort laser pulses of variable width τlas (0.2-12 ps) have been measured by optical microscopy. For increasing laser pulse width τlas < 3 ps, a drastic (threefold) drop of the ablation threshold of aluminum has been observed for visible pulses compared to an almost negligible threshold variation for IR pulses. In contrast, the ablation threshold in silicon increases threefold with increasing τlas for IR pulses, while the corresponding thresholds for visible pulses remained almost constant. In aluminum, such a width-dependent decrease in ablation thresholds has been related to strongly diminished temperature gradients for pulse widths exceeding the characteristic electron-phonon thermalization time. In silicon, the observed increase in ablation thresholds has been ascribed to two-photon IR excitation, while in the visible range linear absorption of the material results in almost constant thresholds.

Areal distribution and concentrations of contaminants of concern in surficial streambed and lakebed sediments, Lake Erie-Lake Saint Clair Drainages, 1990-97

USGS Publications Warehouse

Rheaume, S.J.; Button, D.T.; Myers, Donna N.; Hubbell, D.L.

2001-01-01

Concerns about elevated concentrations of contaminants such as polychlorinated biphenyls and mercury in aquatic bed sediments throughout the Great Lakes Basin have resulted in a need for better understanding of the scope and severity of the problem. Various organochlorine pesticides, polychlorinated biphenyls, trace metals, and polycyclic aromatic hydrocarbons are a concern because of their ability to persist and accumulate in aquatic sediments and their association with adverse aquatic biological effects. The areal distribution and concentrations in surficial bed sediments of 20 contaminants of concern with established bed-sediment-toxicity guidelines were examined in relation to their potential effects on freshwater aquatic biota. Contaminants at more than 800 sampling locations are characterized in this report. Surficial bed-sediment-quality data collected from 1990 to 1997 in the Lake Erie?Lake Saint Clair Drainages were evaluated to reflect recent conditions. In descending order, concentrations of total polycyclic aromatic hydrocarbons, phenanthrene, total polychlorinated biphenyls, chrysene, benz[a]anthracene, benzo[a]pyrene, cadmium, lead, zinc, arsenic, and mercury were the contaminants that most commonly exceeded levels associated with probable adverse effects on aquatic benthic organisms. The highest concentrations of most of these contaminants in aquatic bed sediments are confined to the 12 specific geographic Areas of Concern identified in the 1987 Revisions to the Great Lakes Water Quality Agreement of 1972. An exception is arsenic, which was detected at concentrations exceeding threshold effect levels at many locations outside Areas of Concern.

Total mercury, methyl mercury, and heavy metal concentrations in Hyeongsan River and its tributaries in Pohang city, South Korea.

PubMed

Bailon, Mark Xavier; David, Anneschel Sheehan; Park, Yeongeon; Kim, Eunhee; Hong, Yongseok

2018-04-11

Heavy metal contamination in aquatic systems is a big problem in many areas around the world. In 2016, high mercury concentrations were reported in bivalves (Corbicula leana) and sediments near the confluence of the Hyeongsan River and Chilseong Creek located in Pohang, a steel industrial city in the south-east coast of the Korean peninsula. Given that both the Chilseong and Gumu creeks run through the Pohang industrial complex and ultimately flow to the Hyeongsan River, it is imperative to determine if the industrial effluents have any impact on the mercury contamination in these two streams and the Hyeongsan River. In this work, we investigated the concentration levels of different heavy metals using cold vapor atomic fluorescence spectroscopy and inductively coupled plasma-mass spectroscopy. The metal concentration in the water samples from the Hyeongsan River, Gumu Creek, and Chilseong Creek did not exceed the limits for drinking water quality set by the US EPA and World Health Organization. However, the sediment samples were found to be heavily contaminated by Hg with levels exceeding the toxic effect threshold. Gumu Creek was found to be heavily contaminated. The concentrations of the different heavy metals increased downstream, and the samples collected from the sites in the Hyeongsan River near the Gumu Creek, an open channel for wastewater discharge of companies in the Pohang Industrial Complex, showed higher contamination levels, indicating that the effluents from the industrial complex are a possible source of contamination in the river.

Multivariate analysis for source identification of pollution in sediment of Linggi River, Malaysia.

PubMed

Elias, Md Suhaimi; Ibrahim, Shariff; Samuding, Kamarudin; Rahman, Shamsiah Ab; Wo, Yii Mei; Daung, Jeremy Andy Dominic

2018-03-29

Rapid socioeconomic development in the Linggi River Basin has contributed to the significant increase of pollution discharge into the Linggi River and its adjacent coastal areas. The toxic element contents and distributions in the sediment samples collected along the Linggi River were determined using neutron activation analysis (NAA) and inductively coupled plasma-mass spectrometry (ICP-MS) techniques. The measured mean concentration of As, Cd, Pb, Sb, U, Th and Zn is relatively higher compared to the continental crust value of the respective element. Most of the elements (As, Cr, Fe, Pb, Sb and Zn) exceeded the freshwater sediment quality guideline-threshold effect concentration (FSQG-TEC) value. Downstream stations of the Linggi River showed that As concentrations in sediment exceeded the freshwater sediment quality guideline-probable effect concentration (FSQG-PEC) value. This indicates that the concentration of As will give an adverse effect to the growth of sediment-dwelling organisms. Generally, the Linggi River sediment can be categorised as unpolluted to strongly polluted and unpolluted to strongly to extremely polluted. The correlation matrix of metal-metal relationship, principle component analysis (PCA) and cluster analysis (CA) indicates that the pollution sources of Cu, Ni, Zn, Cd and Pb in sediments of the Linggi River originated from the industry of electronics and electroplating. Elements of As, Cr, Sb and Fe mainly originated from motor-vehicle workshops and metal work, whilst U and Th originated from natural processes such as terrestrial runoff and land erosion.

Methods, apparatus and system for notification of predictable memory failure

DOEpatents

Cher, Chen-Yong; Andrade Costa, Carlos H.; Park, Yoonho; Rosenburg, Bryan S.; Ryu, Kyung D.

2017-01-03

A method for providing notification of a predictable memory failure includes the steps of: obtaining information regarding at least one condition associated with a memory; calculating a memory failure probability as a function of the obtained information; calculating a failure probability threshold; and generating a signal when the memory failure probability exceeds the failure probability threshold, the signal being indicative of a predicted future memory failure.

Optimal maintenance policy incorporating system level and unit level for mechanical systems

NASA Astrophysics Data System (ADS)

Duan, Chaoqun; Deng, Chao; Wang, Bingran

2018-04-01

The study works on a multi-level maintenance policy combining system level and unit level under soft and hard failure modes. The system experiences system-level preventive maintenance (SLPM) when the conditional reliability of entire system exceeds SLPM threshold, and also undergoes a two-level maintenance for each single unit, which is initiated when a single unit exceeds its preventive maintenance (PM) threshold, and the other is performed simultaneously the moment when any unit is going for maintenance. The units experience both periodic inspections and aperiodic inspections provided by failures of hard-type units. To model the practical situations, two types of economic dependence have been taken into account, which are set-up cost dependence and maintenance expertise dependence due to the same technology and tool/equipment can be utilised. The optimisation problem is formulated and solved in a semi-Markov decision process framework. The objective is to find the optimal system-level threshold and unit-level thresholds by minimising the long-run expected average cost per unit time. A formula for the mean residual life is derived for the proposed multi-level maintenance policy. The method is illustrated by a real case study of feed subsystem from a boring machine, and a comparison with other policies demonstrates the effectiveness of our approach.

Forecast-based interventions can reduce the health and economic burden of wildfires.

PubMed

Rappold, Ana G; Fann, Neal L; Crooks, James; Huang, Jin; Cascio, Wayne E; Devlin, Robert B; Diaz-Sanchez, David

2014-09-16

We simulated public health forecast-based interventions during a wildfire smoke episode in rural North Carolina to show the potential for use of modeled smoke forecasts toward reducing the health burden and showed a significant economic benefit of reducing exposures. Daily and county wide intervention advisories were designed to occur when fine particulate matter (PM2.5) from smoke, forecasted 24 or 48 h in advance, was expected to exceed a predetermined threshold. Three different thresholds were considered in simulations, each with three different levels of adherence to the advisories. Interventions were simulated in the adult population susceptible to health exacerbations related to the chronic conditions of asthma and congestive heart failure. Associations between Emergency Department (ED) visits for these conditions and daily PM2.5 concentrations under each intervention were evaluated. Triggering interventions at lower PM2.5 thresholds (≤ 20 μg/m(3)) with good compliance yielded the greatest risk reduction. At the highest threshold levels (50 μg/m(3)) interventions were ineffective in reducing health risks at any level of compliance. The economic benefit of effective interventions exceeded $1 M in excess ED visits for asthma and heart failure, $2 M in loss of productivity, $100 K in respiratory conditions in children, and $42 million due to excess mortality.

Mercury and selenium accumulation in the Colorado River food web, Grand Canyon, USA

USGS Publications Warehouse

Walters, David M.; E.J. Rosi-Marshall,; Kennedy, Theodore A.; W.F. Cross,; C.V. Baxter,

2015-01-01

Mercury (Hg) and selenium (Se) biomagnify in aquatic food webs and are toxic to fish and wildlife. The authors measured Hg and Se in organic matter, invertebrates, and fishes in the Colorado River food web at sites spanning 387 river km downstream of Glen Canyon Dam (AZ, USA). Concentrations were relatively high among sites compared with other large rivers (mean wet wt for 6 fishes was 0.17–1.59 μg g–1 Hg and 1.35–2.65 μg g–1 Se), but consistent longitudinal patterns in Hg or Se concentrations relative to the dam were lacking. Mercury increased (slope = 0.147) with δ15N, a metric of trophic position, indicating biomagnification similar to that observed in other freshwater systems. Organisms regularly exceeded exposure risk thresholds for wildlife and humans (6–100% and 56–100% of samples for Hg and Se, respectfully, among risk thresholds). In the Colorado River, Grand Canyon, Hg and Se concentrations pose exposure risks for fish, wildlife, and humans, and the findings of the present study add to a growing body of evidence showing that remote ecosystems are vulnerable to long-range transport and subsequent bioaccumulation of contaminants. Management of exposure risks in Grand Canyon will remain a challenge, as sources and transport mechanisms of Hg and Se extend far beyond park boundaries. Environ Toxicol Chem2015;9999:1–10

Chemical speciation and ecological risk assessment of arsenic in marine sediments from Izmir Bay (Eastern Aegean Sea).

PubMed

Gonul, L T

2015-12-01

Total arsenic, arsenic(III) and (V), Fe, and Mn were measured in 17 surface sediment samples from Izmir Bay. The concentrations and ecological risk of As were characterized in the sediment affected by urban and agricultural activities. Total As ranged from 8.87 to 28.3 μg g(-1) dry weight (96.5-99.9 % as inorganic As). Distribution of total As and total As/Fe followed a different trend in sediments at all sampling sites. Arsenite (As(III)) was the most dominant form followed by As(V), while organic arsenic represented a minor constituent (0.03 to 3.49 %). The highest concentration of total As was observed at Gediz River estuary and exceeded lower threshold value (threshold effects level (TEL)). Due to the biological reduction of As(V) and abundance of Fe (oxyhydr)oxides in the sediments, most inorganic As in the Izmir Bay was present as As(III). Besides, the levels of As were >TEL and

The Mine Safety and Health Administration's criterion threshold value policy increases miners' risk of pneumoconiosis.

PubMed

Weeks, James L

2006-06-01

The Mine Safety and Health Administration (MSHA) proposes to issue citations for non-compliance with the exposure limit for respirable coal mine dust when measured exposure exceeds the exposure limit with a "high degree of confidence." This criterion threshold value (CTV) is derived from the sampling and analytical error of the measurement method. This policy is based on a combination of statistical and legal reasoning: the one-tailed 95% confidence limit of the sampling method, the apparent principle of due process and a standard of proof analogous to "beyond a reasonable doubt." This policy raises the effective exposure limit, it is contrary to the precautionary principle, it is not a fair sharing of the burden of uncertainty, and it employs an inappropriate standard of proof. Its own advisory committee and NIOSH have advised against this policy. For longwall mining sections, it results in a failure to issue citations for approximately 36% of the measured values that exceed the statutory exposure limit. Citations for non-compliance with the respirable dust standard should be issued for any measure exposure that exceeds the exposure limit.

Partial least squares for efficient models of fecal indicator bacteria on Great Lakes beaches

USGS Publications Warehouse

Brooks, Wesley R.; Fienen, Michael N.; Corsi, Steven R.

2013-01-01

At public beaches, it is now common to mitigate the impact of water-borne pathogens by posting a swimmer's advisory when the concentration of fecal indicator bacteria (FIB) exceeds an action threshold. Since culturing the bacteria delays public notification when dangerous conditions exist, regression models are sometimes used to predict the FIB concentration based on readily-available environmental measurements. It is hard to know which environmental parameters are relevant to predicting FIB concentration, and the parameters are usually correlated, which can hurt the predictive power of a regression model. Here the method of partial least squares (PLS) is introduced to automate the regression modeling process. Model selection is reduced to the process of setting a tuning parameter to control the decision threshold that separates predicted exceedances of the standard from predicted non-exceedances. The method is validated by application to four Great Lakes beaches during the summer of 2010. Performance of the PLS models compares favorably to that of the existing state-of-the-art regression models at these four sites.

Temperature increasing in titanium implants using a high-intensity diode laser for peri-implantitis decontamination

NASA Astrophysics Data System (ADS)

Faustino, C. N.; Ana, A. P.; Bachman, L.

2018-02-01

Peri-implantitis is a destructive inflammatory process that affects the tissues that provide support to the dental implant, the bone and gingiva, and can lead to the loss of the implant. Among the treatments of this disease, the irradiation of the contaminated surface with high intensity lasers is considered a promising alternative; Thus, irradiation parameters must be correctly adjusted in order to promote an efficient and safe treatment. This study investigated the temperature changes at the implant-bone interface during simulated implant surface decontamination using an 808nm diode laser. Dental implants were inserted in bovine bone, in which an artificial periimplant bone defect was made. Access holes of 0.5mm diameter were drilled to allow the positioning of four Ktype thermocouples in different regions: T0 Implant-bone interface, T1 inside the implant, T2 In the bone defect, T3 In the apex of the implant. For laser irradiation, an optical fiber was used at a distance of 0.5mm from the implant surface, and the mean output power varied between 0.5 to 3.0W on both pulsed (PW) and continuous (CW) wave modes. Irradiations were performed by 60s, and the temperature rises were registered for a period of 180s. It was observed that the critical threshold of 47ºC was exceeded at T0, T1 e T2 thermocouples when irradiations were performed at 1.0W; for T3 thermocouple, the threshold was exceeded at 3.0W CW mode. For PW mode, the thermocouples T0, T1, T2 had the threshold exceeded at the power of 1,0W and for T3 the threshold was exceeded at 3.0W. Decontamination of implant surfaces using the diode laser did not excessively heat the implant-bone interface within the mean output power ranging from 0.5 to 1.0W; however, the temperature rise is critical when using the mean power of 0.5W CW and 1.0W PW. Thus, using the PW mode up to the power of 1W seems to be a promising parameter for a safe clinical application.

Threshold exceedance risk assessment in complex space-time systems

NASA Astrophysics Data System (ADS)

Angulo, José M.; Madrid, Ana E.; Romero, José L.

2015-04-01

Environmental and health impact risk assessment studies most often involve analysis and characterization of complex spatio-temporal dynamics. Recent developments in this context are addressed, among other objectives, to proper representation of structural heterogeneities, heavy-tailed processes, long-range dependence, intermittency, scaling behavior, etc. Extremal behaviour related to spatial threshold exceedances can be described in terms of geometrical characteristics and distribution patterns of excursion sets, which are the basis for construction of risk-related quantities, such as in the case of evolutionary study of 'hotspots' and long-term indicators of occurrence of extremal episodes. Derivation of flexible techniques, suitable for both the application under general conditions and the interpretation on singularities, is important for practice. Modern risk theory, a developing discipline motivated by the need to establish solid general mathematical-probabilistic foundations for rigorous definition and characterization of risk measures, has led to the introduction of a variety of classes and families, ranging from some conceptually inspired by specific fields of applications, to some intended to provide generality and flexibility to risk analysts under parametric specifications, etc. Quantile-based risk measures, such as Value-at-Risk (VaR), Average Value-at-Risk (AVaR), and generalization to spectral measures, are of particular interest for assessment under very general conditions. In this work, we study the application of quantile-based risk measures in the spatio-temporal context in relation to certain geometrical characteristics of spatial threshold exceedance sets. In particular, we establish a closed-form relationship between VaR, AVaR, and the expected value of threshold exceedance areas and excess volumes. Conditional simulation allows us, by means of empirical global and local spatial cumulative distributions, the derivation of various statistics of practical interest, and subsequent construction of dynamic risk maps. Further, we study the implementation of static and dynamic spatial deformation under this setup, meaningful, among other aspects, for incorporation of heterogeneities and/or covariate effects, or consideration of external factors for risk measurement. We illustrate this approach though Environment and Health applications. This work is partially supported by grant MTM2012-32666 of the Spanish Ministry of Economy and Competitiveness (co-financed by FEDER).

Psychological differences between children with and without chronic encopresis.

PubMed

Cox, Daniel J; Morris, James B; Borowitz, Stephen M; Sutphen, James L

2002-01-01

To validate a theoretical model of encopresis in terms of psychological factors that differentiates children with and without chronic encopresis and to identify scales that demonstrate these differences. Eighty-six children with encopresis were compared to 62 nonsymptomatic children on five psychometric instruments. Differences in the mean scores and the percentages of children falling beyond preselected clinical thresholds were compared across the patient-control groups. Children with encopresis were found to have more anxiety/depression symptoms, family environments with less expressiveness and poorer organization, more attention difficulties, greater social problems, more disruptive behavior, and poorer school performance (ps =.01 < or =.001 on 15/20 subscales). There were no differences in self-esteem. On those subscales where proportionately more encopretic children exceeded clinical thresholds, approximately 20% more of the encopretic children exceeded thresholds than control children. As a group, children with encopresis differ from children without encopresis on a variety of psychological parameters. However, only a minority of children with encopresis demonstrated clinically significant elevations in these parameters. Identification and treatment of such clinical issues may enhance treatment efficacy.

Sb-related defects in Sb-doped ZnO thin film grown by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Luo, Caiqin; Ho, Lok-Ping; Azad, Fahad; Anwand, Wolfgang; Butterling, Maik; Wagner, Andreas; Kuznetsov, Andrej; Zhu, Hai; Su, Shichen; Ling, Francis Chi-Chung

2018-04-01

Sb-doped ZnO films were fabricated on c-plane sapphire using the pulsed laser deposition method and characterized by Hall effect measurement, X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence, and positron annihilation spectroscopy. Systematic studies on the growth conditions with different Sb composition, oxygen pressure, and post-growth annealing were conducted. If the Sb doping concentration is lower than the threshold ˜8 × 1020 cm-3, the as-grown films grown with an appropriate oxygen pressure could be n˜4 × 1020 cm-3. The shallow donor was attributed to the SbZn related defect. Annealing these samples led to the formation of the SbZn-2VZn shallow acceptor which subsequently compensated for the free carrier. For samples with Sb concentration exceeding the threshold, the yielded as-grown samples were highly resistive. X-ray diffraction results showed that the Sb dopant occupied the O site rather than the Zn site as the Sb doping exceeded the threshold, whereas the SbO related deep acceptor was responsible for the high resistivity of the samples.

Toxicity threshold of chitosan for the subterranean termite, Reticulitermes flavipes

Treesearch

Olanrewaju Raji; Telmah Telmadarrehei; Juliet D. Tang; Dragica Jeremic

2015-01-01

Chitosan is a hydrophilic and biodegradable polysaccharide with antimicrobial properties. It has low toxicity to non-target organisms and is considered an environmentally friendly preservative. In this study, the efficacy of chitosan polymer (> 50 kDa) as a wood preservative was evaluated against the subterranean termites Reticulitermes flavipes...

MODELING THE INTERACTION THRESHOLD: THE BREAK-POINT BETWEEN ADDITIVITY AND NON-ADDITIVITY

EPA Science Inventory

Dose-dependent changes in toxicity mechanisms of single chemicals may take place along the full dose-response spectrum. At high doses, the possibility exists for some steps in the principle mechanism of toxicity to shift to other mechanisms. The possibility of mechanism shifts fo...

Assessing lead thresholds for phytotoxicity and potential dietary toxicity in selected vegetable crops.

PubMed

Hong, C L; Jia, Y B; Yang, X E; He, Z L; Stoffella, P J

2008-04-01

Lead tolerance and accumulation in shoots and edible parts varied with crop species and soil type. The critical Pb concentrations at 10% yield reduction were 24.71, 28.25, and 0.567 mg kg(-1) for pakchoi, celery, and hot pepper, respectively under hydroponic conditions, whereas were 13.1, 3.83, 0.734 mg kg(-1) grown in the Inceptisol and 31.7, 30.0, 0.854 mg kg(-1) in the Alluvial soil, respectively. Based on the threshold of human dietary toxicity for Pb, the critical levels of soil available Pb for pakchoi, celery, and hot pepper were 5.07, 8.06, and 0.48 mg kg(-1) for the Inceptisol, and 1.38, 1.47, and 0.162 mg kg(-1) for the Alluvial soil, respectively. Similarly, the total soil Pb thresholds were different from vegetable species and soil types.

On the expected discounted penalty functions for two classes of risk processes under a threshold dividend strategy

NASA Astrophysics Data System (ADS)

Lu, Zhaoyang; Xu, Wei; Sun, Decai; Han, Weiguo

2009-10-01

In this paper, the discounted penalty (Gerber-Shiu) functions for a risk model involving two independent classes of insurance risks under a threshold dividend strategy are developed. We also assume that the two claim number processes are independent Poisson and generalized Erlang (2) processes, respectively. When the surplus is above this threshold level, dividends are paid at a constant rate that does not exceed the premium rate. Two systems of integro-differential equations for discounted penalty functions are derived, based on whether the surplus is above this threshold level. Laplace transformations of the discounted penalty functions when the surplus is below the threshold level are obtained. And we also derive a system of renewal equations satisfied by the discounted penalty function with initial surplus above the threshold strategy via the Dickson-Hipp operator. Finally, analytical solutions of the two systems of integro-differential equations are presented.

Flight thresholds and seasonal variations in flight activity of the light-brown apple moth, Epiphyas postvittana (Walk.) (Tortricidae), in Victoria, Australia.

PubMed

Danthanarayana, W

1976-12-01

The flight activity of Epiphyas postvittana was studied at two sites near Melbourne with the aid of suction traps, over a period of 4 years. Maximum numbers were found to fly during the period September to March with peak activity coinciding with the emergence of winter, spring and summer generation moths. E. postivittana is predominantly a nocturnal flier with maximum activity around 20.00-24.00 h. The lower temperature threshold of flight was 8-11°C. The upper temperature threshold varied from 20-21°C, 24-25°C and 27-28°C for the winter, spring and summer generation moths respectively. Flight was highly influenced by the prevailing wind. The lower wind speed threshold was 0.5-0.8 m -s and the upper wind speed threshold was 2.6-2.7 m -s . The relationship between wind speed and the amount of flight was non-linear, with the frequency of flights decreasing sharply with increasing wind speed. No flights occurred at wind speeds greater than 2.8 m -s . Variation in relative humidity had no influence on flight, but lack of rain favoured flight. The amount of flight activity and the amount of rainfall were negatively correlated; flights did not occur when the daily precipitation exceeded 32.5 mm, and with a precipitation exceeding 39 mm no flights could be expected. The value of these findings to pest control programmes is discussed.

The benefits and tradeoffs for varied high-severity injury risk thresholds for advanced automatic crash notification systems.

PubMed

Bahouth, George; Graygo, Jill; Digges, Kennerly; Schulman, Carl; Baur, Peter

2014-01-01

The objectives of this study are to (1) characterize the population of crashes meeting the Centers for Disease Control and Prevention (CDC)-recommended 20% risk of Injury Severity Score (ISS)>15 injury and (2) explore the positive and negative effects of an advanced automatic crash notification (AACN) system whose threshold for high-risk indications is 10% versus 20%. Binary logistic regression analysis was performed to predict the occurrence of motor vehicle crash injuries at both the ISS>15 and Maximum Abbreviated Injury Scale (MAIS) 3+ level. Models were trained using crash characteristics recommended by the CDC Committee on Advanced Automatic Collision Notification and Triage of the Injured Patient. Each model was used to assign the probability of severe injury (defined as MAIS 3+ or ISS>15 injury) to a subset of NASS-CDS cases based on crash attributes. Subsequently, actual AIS and ISS levels were compared with the predicted probability of injury to determine the extent to which the seriously injured had corresponding probabilities exceeding the 10% and 20% risk thresholds. Models were developed using an 80% sample of NASS-CDS data from 2002 to 2012 and evaluations were performed using the remaining 20% of cases from the same period. Within the population of seriously injured (i.e., those having one or more AIS 3 or higher injuries), the number of occupants whose injury risk did not exceed the 10% and 20% thresholds were estimated to be 11,700 and 18,600, respectively, each year using the MAIS 3+ injury model. For the ISS>15 model, 8,100 and 11,000 occupants sustained ISS>15 injuries yet their injury probability did not reach the 10% and 20% probability for severe injury respectively. Conversely, model predictions suggested that, at the 10% and 20% thresholds, 207,700 and 55,400 drivers respectively would be incorrectly flagged as injured when their injuries had not reached the AIS 3 level. For the ISS>15 model, 87,300 and 41,900 drivers would be incorrectly flagged as injured when injury severity had not reached the ISS>15 injury level. This article provides important information comparing the expected positive and negative effects of an AACN system with thresholds at the 10% and 20% levels using 2 outcome metrics. Overall, results suggest that the 20% risk threshold would not provide a useful notification to improve the quality of care for a large number of seriously injured crash victims. Alternately, a lower threshold may increase the over triage rate. Based on the vehicle damage observed for crashes reaching and exceeding the 10% risk threshold, we anticipate that rescue services would have been deployed based on current Public Safety Answering Point (PSAP) practices.

Operational EEW Networks in Turkey

NASA Astrophysics Data System (ADS)

Zulfikar, Can; Pinar, Ali

2016-04-01

There are several EEW networks and algorithms under operation in Turkey. The first EEW system was deployed in Istanbul in 2002 after the 1999 Mw7.4 Kocaeli and Mw7.1 Duzce earthquake events. The system consisted of 10 strong motion stations located as close as possible to the main Marmara Fault line. The system was upgraded by 5 OBS (Ocean Bottom Seismometer) in 2012 located in Marmara Sea. The system works in threshold based algorithm. The alert is given according to exceedance of certain threshold levels of amplitude of ground motion acceleration in certain time interval at least in 3 stations. Currently, there are two end-users of EEW system in Istanbul. The critical facilities of Istanbul Gas Distribution Company (IGDAS) and Marmaray Tube tunnel receives the EEW information in order to activate their automatic shut-off mechanisms. The IGDAS has their own strong motion network located at their district regulators. After receiving the EEW signal if the threshold values of ground motion parameters are exceeded the gas-flow is cut automatically at the district regulators. The IGDAS has 750 district regulators distributed in Istanbul. At the moment, the 110 of them are instrumented with strong motion accelerometers. As a 2nd stage of the on-going project, the IGDAS company proposes to install strong motion accelerometers to all remaining district regulators. The Marmaray railway tube tunnel is the world's deepest immersed tube tunnel with 60m undersea depth. The tunnel has 1.4km length with 13 segments. The tunnel is monitored with 2 strong motion accelerometers in each segment, 26 in total. Once the EEW signal is received, the monitoring system is activated and the recording ground motion parameters are calculated in real-time. Depending on the exceedance of threshold levels, further actions are taken such as reducing the train speed, stopping the train before entering the tunnel etc. In Istanbul, there are also on-site EEW system applied in several high-rise buildings. As similar to threshold based algorithm, once the threshold level is exceeded in several strong motion accelerometers installed in the high-rise building, the automated shut-off mechanism is activated in order to prevent secondary damage effects of the earthquakes. In addition to the threshold based EEW system, the regional EEW algorithms Virtual Seismologist (VS) as implemented in SeisComP3 VS(SC3) and PRESTo have been also implemented in Marmara region of Turkey. These applications use the regional seismic networks. The purpose of the regional EEW systems is to determine the magnitude and location of the event from the P-wave information of the closest 3-4 stations and forward this information to interested sites. The regional EEW systems are also important for Istanbul in order to detect far distance earthquake events and provide alert especially for the high-rise buildings for their long duration shaking.

499 E Illinois, November 2012, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements did not exceed the respective field instrument threshold value previously stated andmaximum values observed at each lift ranged from approximately 10,700 to 12,600 cpm unshielded

Toxics Release Inventory Expansion Rule Phase 3 (TRI-P3)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evans, R.A.; Saunders, A.D.; Worley, G.G.

1998-09-01

The ORR [East Tennessee Technology Park (ETTP), Y-12 Plant, and Oak Ridge National Laboratory (ORNL)] is considered a single facility for reporting by the DOE prime contractors. The processing, manufacturing, or "otherwise use" Section313 chemicals are combined to determine TRI reportability. Such is the case with lead metal, which is one of two chemicals for which reportin~ forms were prepared in this pilot study (Task 2;1. The lead shop at ORNL exceeded the reporting threshold, causing a lead activity at a Y-1 2 machine shop and lead in waste at ETTP to be reportable. TRI-P3 report preparation time for leadmore » totaled 36.5 hours. The second chemical investigated and reported (chromium) also required nearly a man-week for report preparation and documentation by experienced TRI personnel. The ORR TRI report typically includes about six chemicals, so an estimate of the TRI-P3 incremental reporting burden for ORR would be six weeks for experienced personnel axI d two/three man-months for first-time ORR preparers.« less

Ocular response to hydrogen peroxide.

PubMed

Paugh, J R; Brennan, N A; Efron, N

1988-02-01

A controlled, randomized, double-masked study was conducted on eight human subjects to determine the threshold level of hydrogen peroxide, which is toxic when introduced into the eye via a high water content (75%; Durasoft 4) hydrogel contact lens. Subjective comfort, conjunctival hyperemia, corneal and conjunctival epithelial staining, and corneal oxygen uptake were assessed in response to 5-min wear of lenses that were presoaked in isotonic saline solutions of physiologic pH containing 0, 25, 50, 100, 200, 400, and 800 parts per million (ppm) hydrogen peroxide. Higher levels of hydrogen peroxide were associated with greater discomfort (p less than 0.05) and increased conjunctival hyperemia (p less than 0.001). The highest level of hydrogen peroxide tested (800 ppm) did not induce significant corneal or conjunctival epithelial staining or alter the corneal aerobic response. We conclude that residual concentrations of hydrogen peroxide in contact lens care systems should not exceed 100 ppm. Practitioners can use these data to estimate the level of residual hydrogen peroxide to which a patient may have been exposed upon lens application after neutralization.

Estimation of southern resident killer whale exposure to exhaust emissions from whale-watching vessels and potential adverse health effects and toxicity thresholds.

PubMed

Lachmuth, Cara L; Barrett-Lennard, Lance G; Steyn, D Q; Milsom, William K

2011-04-01

Southern resident killer whales in British Columbia and Washington are exposed to heavy vessel traffic. This study investigates their exposure to exhaust gases from whale-watching vessels by using a simple dispersion model incorporating data on whale and vessel behavior, atmospheric conditions, and output of airborne pollutants from the whale-watching fleet based on emissions data from regulatory agencies. Our findings suggest that current whale-watching guidelines are usually effective in limiting pollutant exposure to levels at or just below those at which measurable adverse health effects would be expected in killer whales. However, safe pollutant levels are exceeded under worst-case conditions and certain average-case conditions. To reduce killer whale exposure to exhaust we recommend: vessels position on the downwind side of whales, a maximum of 20 whale-watching vessels should be within 800 m at any given time, viewing periods should be limited, and current whale-watch guidelines and laws should be enforced. Copyright © 2011. Published by Elsevier Ltd.

40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

40 CFR 227.8 - Limitations on the disposal rates of toxic wastes.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.8 Limitations on the disposal rates of toxic wastes. No wastes will be deemed acceptable for ocean dumping unless such wastes can be dumped so as not to exceed the limiting permissible...

Mercury, hydroquinone and clobetasol propionate in skin lightening products in West Africa and Canada.

PubMed

Gbetoh, Mètogbé Honoré; Amyot, Marc

2016-10-01

Skin lightening products are types of cosmetics (creams, gels, lotions and soaps) applied voluntarily on skin. Several of these products contain a variety of active ingredients that are highly toxic. Among those toxic agents, the present study focuses on mercury, hydroquinone, and clobetasol propionate. Out of the 93 lightening soaps and 98 creams purchased in large city markets in sub-Saharan West Africa and in small ethnic shops in Canada, 68-84% of all creams and 7.5-65% of all soaps exceeded regulatory guidelines for at least one active ingredient when considering different regulations. Mercury was found in high concentrations mainly in soaps, while hydroquinone and clobetasol propionate concentrations exceeded US FDA standards in some creams for all countries included in our study. Concentrations of the three compounds declared on labels of soaps and creams usually did not correspond to concentrations actually measured, particularly for mercury and hydroquinone. Overall, our results indicate that most studied skin-lightening products are potentially toxic and that product labels are frequently inaccurate with respect to the presence of toxic agents. Copyright © 2016 Elsevier Inc. All rights reserved.

The role of the Oregon State University Endophyte Service Laboratory in diagnosing clinical cases of endophyte toxicoses.

PubMed

Craig, A Morrie; Blythe, Linda L; Duringer, Jennifer M

2014-07-30

The Oregon State University Colleges of Veterinary Medicine and Agricultural Sciences instituted the Endophyte Service Laboratory to aid in diagnosing toxicity problems associated with cool-season grasses in livestock. The endophyte (Neotyphodium coenophalum) present in tall fescue (Festuca arundinacea) produces ergopeptine alkaloids, of which ergovaline is the molecule used to determine exposure and toxicity thresholds for the vasoconstrictive conditions "fescue foot" and "summer slump". Another vasoconstrictive syndrome, "ergotism," is caused by a parasitic fungus, Claviceps purpurea, and its primary toxin, ergotamine. "Ryegrass staggers" is a neurological condition that affects livestock consuming endophyte (Neotyphodium lolii)-infected perennial ryegrass (Lolium perenne) with high levels of lolitrem B. HPLC-fluorescent analytical methods for these mycotoxins are described and were used to determine threshold levels of toxicity for ergovaline and lolitrem B in cattle, sheep, horses, and camels. In addition, six clinical cases in cattle are presented to illustrate diagnosis of these three diseases.

Hazards to wildlife from soil-borne cadmium reconsidered

USGS Publications Warehouse

Beyer, W.N.

2000-01-01

Cadmium is a toxic element that should be included in environmental risk assessments of contaminated soils. This paper argues, however, that hazards to wildlife from cadmium have often been overstated. The literature contains only meager evidence that wild animals have been seriously harmed by cadmium, even at severely contaminated sites. Although some researchers have reported that wildlife have accumulated concentrations of cadmium in their kidneys that were above suggested injury thresholds, the thresholds may be disputed, since they were well below the World Health Organization criterion of 200 mg/kg (wet weight) of cadmium in the renal cortex for protecting human health. Recent risk assessments have concluded that soil cadmium concentrations less than 1 mg/kg are toxic to soil organisms and wildlife, which implies that background concentrations of cadmium naturally found in soils are hazardous. An examination of the databases used to support these assessments suggested that the toxicity of cadmium has been exaggerated.

PROUCL 4.0 SOFTWARE

EPA Science Inventory

Statistical inference, including both estimation and hypotheses testing approaches, is routinely used to: estimate environmental parameters of interest, such as exposure point concentration (EPC) terms, not-to-exceed values, and background level threshold values (BTVs) for contam...

48 CFR 225.7002-2 - Exceptions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of the Army. (iii) The Secretary of the Navy. (iv) The Secretary of the Air Force. (v) The Director... product; and (2) Does not exceed the simplified acquisition threshold. (k) Acquisitions of waste and...

Modelling the regional variability of the probability of high trihalomethane occurrence in municipal drinking water.

PubMed

Cool, Geneviève; Lebel, Alexandre; Sadiq, Rehan; Rodriguez, Manuel J

2015-12-01

The regional variability of the probability of occurrence of high total trihalomethane (TTHM) levels was assessed using multilevel logistic regression models that incorporate environmental and infrastructure characteristics. The models were structured in a three-level hierarchical configuration: samples (first level), drinking water utilities (DWUs, second level) and natural regions, an ecological hierarchical division from the Quebec ecological framework of reference (third level). They considered six independent variables: precipitation, temperature, source type, seasons, treatment type and pH. The average probability of TTHM concentrations exceeding the targeted threshold was 18.1%. The probability was influenced by seasons, treatment type, precipitations and temperature. The variance at all levels was significant, showing that the probability of TTHM concentrations exceeding the threshold is most likely to be similar if located within the same DWU and within the same natural region. However, most of the variance initially attributed to natural regions was explained by treatment types and clarified by spatial aggregation on treatment types. Nevertheless, even after controlling for treatment type, there was still significant regional variability of the probability of TTHM concentrations exceeding the threshold. Regional variability was particularly important for DWUs using chlorination alone since they lack the appropriate treatment required to reduce the amount of natural organic matter (NOM) in source water prior to disinfection. Results presented herein could be of interest to authorities in identifying regions with specific needs regarding drinking water quality and for epidemiological studies identifying geographical variations in population exposure to disinfection by-products (DBPs).

Smart sensing to drive real-time loads scheduling algorithm in a domotic architecture

NASA Astrophysics Data System (ADS)

Santamaria, Amilcare Francesco; Raimondo, Pierfrancesco; De Rango, Floriano; Vaccaro, Andrea

2014-05-01

Nowadays the focus on power consumption represent a very important factor regarding the reduction of power consumption with correlated costs and the environmental sustainability problems. Automatic control load based on power consumption and use cycle represents the optimal solution to costs restraint. The purpose of these systems is to modulate the power request of electricity avoiding an unorganized work of the loads, using intelligent techniques to manage them based on real time scheduling algorithms. The goal is to coordinate a set of electrical loads to optimize energy costs and consumptions based on the stipulated contract terms. The proposed algorithm use two new main notions: priority driven loads and smart scheduling loads. The priority driven loads can be turned off (stand by) according to a priority policy established by the user if the consumption exceed a defined threshold, on the contrary smart scheduling loads are scheduled in a particular way to don't stop their Life Cycle (LC) safeguarding the devices functions or allowing the user to freely use the devices without the risk of exceeding the power threshold. The algorithm, using these two kind of notions and taking into account user requirements, manages loads activation and deactivation allowing the completion their operation cycle without exceeding the consumption threshold in an off-peak time range according to the electricity fare. This kind of logic is inspired by industrial lean manufacturing which focus is to minimize any kind of power waste optimizing the available resources.

FAF-Drugs2: free ADME/tox filtering tool to assist drug discovery and chemical biology projects.

PubMed

Lagorce, David; Sperandio, Olivier; Galons, Hervé; Miteva, Maria A; Villoutreix, Bruno O

2008-09-24

Drug discovery and chemical biology are exceedingly complex and demanding enterprises. In recent years there are been increasing awareness about the importance of predicting/optimizing the absorption, distribution, metabolism, excretion and toxicity (ADMET) properties of small chemical compounds along the search process rather than at the final stages. Fast methods for evaluating ADMET properties of small molecules often involve applying a set of simple empirical rules (educated guesses) and as such, compound collections' property profiling can be performed in silico. Clearly, these rules cannot assess the full complexity of the human body but can provide valuable information and assist decision-making. This paper presents FAF-Drugs2, a free adaptable tool for ADMET filtering of electronic compound collections. FAF-Drugs2 is a command line utility program (e.g., written in Python) based on the open source chemistry toolkit OpenBabel, which performs various physicochemical calculations, identifies key functional groups, some toxic and unstable molecules/functional groups. In addition to filtered collections, FAF-Drugs2 can provide, via Gnuplot, several distribution diagrams of major physicochemical properties of the screened compound libraries. We have developed FAF-Drugs2 to facilitate compound collection preparation, prior to (or after) experimental screening or virtual screening computations. Users can select to apply various filtering thresholds and add rules as needed for a given project. As it stands, FAF-Drugs2 implements numerous filtering rules (23 physicochemical rules and 204 substructure searching rules) that can be easily tuned.

Potentially toxic elements contamination in urban soils: a comparison of three European cities.

PubMed

Biasioli, M; Grcman, H; Kralj, T; Madrid, F; Díaz-Barrientos, E; Ajmone-Marsan, F

2007-01-01

Studies on several cities around the world confirm that urban soils are subject to heavy anthropogenic disturbance. However, these surveys are difficult to compare due to a lack of common sampling and analytical protocols. In this study the soils of Ljubljana (Slovenia), Sevilla (Spain), and Torino (Italy) were extensively sampled and analyzed using common procedures. Results highlighted similarities across the cities, despite their differences in geography, size, climate, etc. Potentially toxic elements (PTE) showed a wide range in concentration reflecting a diffuse contamination. Among the "urban" elements Pb exceeded the legislation threshold in 45% of Ljubljana, 43% of Torino, and 11% of Sevilla samples while Zn was above the limits in 20, 43, and 2% of the soils of Ljubljana, Torino, and Sevilla, respectively. The distribution of PTE showed no depth-dependant changes, while general soil properties seemed more responsive to anthropogenic influences. Multivariate statistics revealed similar associations between PTE in the three cities, with Cu, Pb, and Zn in a group, and Ni and Cr in another, suggesting an anthropogenic origin for the former group and natural one for the latter. Chromium and Ni were unaffected by land use, except for roadside soils, while Cu, Pb, and Zn distribution appeared to be more dependent on the distance from emission sources. Regardless of the location, climate, and size, the "urban" factor--integrating type and intensity of contaminant emission and anthropogenic disturbance--seems to prevail in determining trends of PTE contamination.

The coevolution of two phytoplankton species on a single resource: allelopathy as a pseudo-mixotrophy.

PubMed

Roy, Shovonlal

2009-02-01

Without the top-down effects and the external/physical forcing, a stable coexistence of two phytoplankton species under a single resource is impossible - a result well known from the principle of competitive exclusion. Here I demonstrate by analysis of a mathematical model that such a stable coexistence in a homogeneous media without any external factor would be possible, at least theoretically, provided (i) one of the two species is toxin producing thereby has an allelopathic effect on the other, and (ii) the allelopathic effect exceeds a critical level. The threshold level of allelopathy required for the coexistence has been derived analytically in terms of the parameters associated with the resource competition and the nutrient recycling. That the extra mortality of a competitor driven by allelopathy of a toxic species gives a positive feed back to the algal growth process through the recycling is explained. And that this positive feed back plays a pivotal role in reducing competition pressures and helping species succession in the two-species model is demonstrated. Based on these specific coexistence results, I introduce and explain theoretically the allelopathic effect of a toxic species as a 'pseudo-mixotrophy'-a mechanism of 'if you cannot beat them or eat them, just kill them by chemical weapons'. The impact of this mechanism of species succession by pseudo-mixotrophy in the form of alleopathy is discussed in the context of current understanding on straight mixotrophy and resource-species relationship among phytoplankton species.

Pesticides from wastewater treatment plant effluents affect invertebrate communities.

PubMed

Münze, Ronald; Hannemann, Christin; Orlinskiy, Polina; Gunold, Roman; Paschke, Albrecht; Foit, Kaarina; Becker, Jeremias; Kaske, Oliver; Paulsson, Elin; Peterson, Märit; Jernstedt, Henrik; Kreuger, Jenny; Schüürmann, Gerrit; Liess, Matthias

2017-12-01

We quantified pesticide contamination and its ecological impact up- and downstream of seven wastewater treatment plants (WWTPs) in rural and suburban areas of central Germany. During two sampling campaigns, time-weighted average pesticide concentrations (c TWA ) were obtained using Chemcatcher® passive samplers; pesticide peak concentrations were quantified with event-driven samplers. At downstream sites, receiving waters were additionally grab sampled for five selected pharmaceuticals. Ecological effects on macroinvertebrate structure and ecosystem function were assessed using the biological indicator system SPEAR pesticides (SPEcies At Risk) and leaf litter breakdown rates, respectively. WWTP effluents substantially increased insecticide and fungicide concentrations in receiving waters; in many cases, treated wastewater was the exclusive source for the neonicotinoid insecticides acetamiprid and imidacloprid in the investigated streams. During the ten weeks of the investigation, five out of the seven WWTPs increased in-stream pesticide toxicity by a factor of three. As a consequence, at downstream sites, SPEAR values and leaf litter degradation rates were reduced by 40% and 53%, respectively. The reduced leaf litter breakdown was related to changes in the macroinvertebrate communities described by SPEAR pesticides and not to altered microbial activity. Neonicotinoids showed the highest ecological relevance for the composition of invertebrate communities, occasionally exceeding the Regulatory Acceptable Concentrations (RACs). In general, considerable ecological effects of insecticides were observed above and below regulatory thresholds. Fungicides, herbicides and pharmaceuticals contributed only marginally to acute toxicity. We conclude that pesticide retention of WWTPs needs to be improved. Copyright © 2017 Elsevier B.V. All rights reserved.

Toxicity assessment of sediments from the Grand Calumet River and Indiana Harbor Canal in northwestern Indiana, USA

USGS Publications Warehouse

Ingersoll, C.G.; MacDonald, D.D.; Brumbaugh, W.G.; Johnson, B. Thomas; Kemble, N.E.; Kunz, J.L.; May, T.W.; Wang, N.; Smith, J.R.; Sparks, D.W.; Ireland, D.S.

2002-01-01

The objective of this study was to evaluate the toxicity of sediments from the Grand Calumet River and Indiana Harbor Canal located in northwestern Indiana, USA. Toxicity tests used in this assessment included 10-day sediment exposures with the amphipod Hyalella azteca, 31-day sediment exposures with the oligochaete Lumbriculus variegatus, and the Microtox® Solid-Phase Sediment Toxicity Test. A total of 30 sampling stations were selected in locations that had limited historic matching toxicity and chemistry data. Toxic effects on amphipod survival were observed in 60% of the samples from the assessment area. Results of a toxicity test with oligochaetes indicated that sediments from the assessment area were too toxic to be used in proposed bioaccumulation testing. Measurement of amphipod length after the 10-day exposures did not provide useful information beyond that provided by the survival endpoint. Seven of the 15 samples that were identified as toxic in the amphipod tests were not identified as toxic in the Microtox test, indicating that the 10-day H. azteca test was more sensitive than the Microtox test. Samples that were toxic tended to have the highest concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). The toxic samples often had an excess of simultaneously extracted metals (SEM) relative to acid volatile sulfide (AVS) and had multiple exceedances of probable effect concentrations (PECs). Metals may have contributed to the toxicity of samples that had both an excess molar concentration of SEM relative to AVS and elevated concentrations of metals in pore water. However, of the samples that had an excess of SEM relative to AVS, only 38% of these samples had elevated concentration of metals in pore water. The lack of correspondence between SEM-AVS and pore water metals indicates that there are variables in addition to AVS controlling the concentrations of metals in pore water. A mean PEC quotient of 3.4 (based on concentrations of metals, PAHs, and PCBs) was exceeded in 33% of the sediment samples and a mean quotient of 0.63 was exceeded in 70% of the thirty sediment samples from the assessment area. A 50% incidence of toxicity has been previously reported in a database for sediment tests with H. azteca at a mean quotient of 3.4 in 10-day exposures and at a mean quotient of 0.63 in 28-day exposures. Among the Indiana Harbor samples, most of the samples with a mean PEC quotient above 0.63 (i.e., 15 of 21; 71%) and above 3.4 (i.e., 10 of 10; 100%) were toxic to amphipods. Results of this study and previous studies demonstrate that sediments from this assessment area are among the most contaminated and toxic that have ever been reported.

Toxicity of sediments and pore water from Brunswick Estuary, Georgia

USGS Publications Warehouse

Winger, Parley V.; Lasier, Peter J.; Geitner, Harvey

1993-01-01

A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.

The Flipside of the Power of Engineered T Cells: Observed and Potential Toxicities of Genetically Modified T Cells as Therapy.

PubMed

Bedoya, Felipe; Frigault, Matthew J; Maus, Marcela V

2017-02-01

Autologous T cells modified to recognize novel antigen targets are a novel form of therapy for cancer. We review the various potential forms of observed and hypothetical toxicities associated with genetically modified T cells. Despite the focus on toxicities in this review, re-directed T cells represent a powerful and highly effective form of anti-cancer therapy; we remain optimistic that the common toxicities will become routinely manageable and that some theoretical toxicity will be exceedingly rare, if ever observed. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Could ecological thresholds of toxicological concern (eco-TTCs) be used to support development of ambient water quality criteria?

EPA Science Inventory

The Threshold of Toxicologic Concern (TTC) is an approach used for a decades in human hazard assessment. A TTC establishes an exposure level for a chemical below which no appreciable risk to human health is expected based upon a de minimis value for toxicity identified for many ...

Efficacy of copper borax preservative against wood decay

Treesearch

William Abbott; Bessie Woodward; Michael West

2001-01-01

In this study, a wood preservative containing active ingredients of 43.5% borax and 3.1% copper hydroxide was evaluated in soil-block tests in accordance with AWPA E10. Results suggested thatthe copper hydroxide was not contributing to fungal toxicity at preservative threshold levels. Thresholds determined for this preservative were very close to those previously...

Pesticide and trace metal occurrence and aquatic benchmark exceedances in surface waters and sediments of urban wetlands and retention ponds in Melbourne, Australia.

PubMed

Allinson, Graeme; Zhang, Pei; Bui, AnhDuyen; Allinson, Mayumi; Rose, Gavin; Marshall, Stephen; Pettigrove, Vincent

2015-07-01

Samples of water and sediments were collected from 24 urban wetlands in Melbourne, Australia, in April 2010, and tested for more than 90 pesticides using a range of gas chromatographic (GC) and liquid chromatographic (LC) techniques, sample 'hormonal' activity using yeast-based recombinant receptor-reporter gene bioassays, and trace metals using spectroscopic techniques. At the time of sampling, there was almost no estrogenic activity in the water column. Twenty-three different pesticide residues were observed in one or more water samples from the 24 wetlands; chemicals observed at more than 40% of sites were simazine (100%), atrazine (79%), and metalaxyl and terbutryn (46%). Using the toxicity unit (TU) concept, less than 15% of the detected pesticides were considered to pose an individual, short-term risk to fish or zooplankton in the ponds and wetlands. However, one pesticide (fenvalerate) may have posed a possible short-term risk to fish (log10TUf > -3), and three pesticides (azoxystrobin, fenamiphos and fenvalerate) may have posed a risk to zooplankton (logTUzp between -2 and -3); all the photosystem II (PSII) inhibiting herbicides may have posed a risk to primary producers in the ponds and wetlands (log10TUap and/or log10TUalg > -3). The wetland sediments were contaminated with 16 different pesticides; no chemicals were observed at more than one third of sites, but based on frequency of detection and concentrations, bifenthrin (33%, maximum 59 μg/kg) is the priority insecticide of concern for the sediments studied. Five sites returned a TU greater than the possible effect threshold (i.e. log10TU > 1) as a result of bifenthrin contamination of their sediments. Most sediments did not exceed Australian sediment quality guideline levels for trace metals. However, more than half of the sites had threshold effect concentration quotients (TECQ) values >1 for Cu (58%), Pb (50%), Ni (67%) and Zn (63%), and 75% of sites had mean probable effect concentration quotients (PECQ) >0.2, suggesting that the collected sediments may have been having some impact on sediment-dwelling organisms.

Navy Pier roundabout, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 2,300 cpm to a maximum of 4,300cpm unshielded.

305 E. Erie Street, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,900 cpm to a maximum of 3,900cpm unshielded.

400-420 N St Clair St, May 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and the spoil materials generatedduring the excavation process did not exceed the respective instrument threshold previously stated witha maximum of 8,000 cpm unshielded.

301-45 E Illinois St, May 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation and the spoil materials generatedduring the excavation process did not exceed the respective instrument threshold previously stated with amaximum of 7,500 cpm unshielded.

215 E. Grand Ave, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,300 cpm to a maximum of 3,500cpm shielded.

360 N. Michigan Ave, January 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation did not exceed the instrument threshold previouslystated with unshielded maximum values of 7,700 cpm and 9,300 cpm in the respective sections of theexcavation.

455 N St Clair St, August 2012, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the spoil materials generated during the drilling process did not exceed the respective threshold values previously stated withthe maximum unshielded gamma reading observed being 5,500 cpm.

Application of the "threshold of toxicological concern" to derive tolerable concentrations of "non-relevant metabolites" formed from plant protection products in ground and drinking water.

PubMed

Melching-Kollmuss, Stephanie; Dekant, Wolfgang; Kalberlah, Fritz

2010-03-01

Limits for tolerable concentrations of ground water metabolites ("non-relevant metabolites" without targeted toxicities and specific classification and labeling) derived from active ingredients (AI) of plant protection products (PPPs) are discussed in the European Union. Risk assessments for "non-relevant metabolites" need to be performed when concentrations are above 0.75 microg/L. Since oral uptake is the only relevant exposure pathway for "non-relevant metabolites", risk assessment approaches as used for other chemicals with predominantly oral exposure in humans are applicable. The concept of "thresholds of toxicological concern" (TTC) defines tolerable dietary intakes for chemicals without toxicity data and is widely applied to chemicals present in food in low concentrations such as flavorings. Based on a statistical evaluation of the results of many toxicity studies and considerations of chemical structures, the TTC concept derives a maximum daily oral intake without concern of 90 microg/person/day for non-genotoxic chemicals, even for those with appreciable toxicity. When using the typical exposure assessment for drinking water contaminants (consumption of 2L of drinking water/person/day, allocation of 10% of the tolerable daily intake to drinking water), a TTC-based upper concentration limit of 4.5 microg/L for "non-relevant metabolites" in ground/drinking water is delineated. In the present publication it has been evaluated, whether this value would cover all relevant toxicities (repeated dose, reproductive and developmental, and immune effects). Taking into account, that after evaluation of specific reproduction toxicity data from chemicals and pharmaceuticals, a value of 1 microg/kgbw/day has been assessed as to cover developmental and reproduction toxicity, a TTC value of 60 microg/person/day was assessed as to represent a safe value. Based on these reasonable worst case assumptions, a TTC-derived threshold of 3 microg/L in drinking water is derived. When a non-relevant metabolite is present in concentration below 3 microg/L, animal testing for toxicity is not considered necessary for a compound-specific risk assessment since the application of the TTC covers all relevant toxicities to be considered in such assessment and any health risk resulting from these exposures is very low. (c) 2009 Elsevier Inc. All rights reserved.

40 CFR 435.13 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... sediment toxicity ratio 6 shall not exceed 1.0. Biodegradation rate Biodegradation rate ratio 7 shall not...). 7 Biodegradation rate ratio = Cumulative headspace gas production (ml) of C16-C18 internal olefin... fluids that meet the base fluid sediment toxicity ratio (Footnote 6), biodegradation rate ratio (Footnote...

40 CFR 435.13 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2014 CFR

2014-07-01

... sediment toxicity ratio 6 shall not exceed 1.0. Biodegradation rate Biodegradation rate ratio 7 shall not...). 7 Biodegradation rate ratio = Cumulative headspace gas production (ml) of C16-C18 internal olefin... fluids that meet the base fluid sediment toxicity ratio (Footnote 6), biodegradation rate ratio (Footnote...

40 CFR 435.13 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... sediment toxicity ratio 6 shall not exceed 1.0. Biodegradation rate Biodegradation rate ratio 7 shall not...). 7 Biodegradation rate ratio = Cumulative headspace gas production (ml) of C16-C18 internal olefin... fluids that meet the base fluid sediment toxicity ratio (Footnote 6), biodegradation rate ratio (Footnote...

Rainfall thresholds as a landslide indicator for engineered slopes on the Irish Rail network

NASA Astrophysics Data System (ADS)

Martinović, Karlo; Gavin, Kenneth; Reale, Cormac; Mangan, Cathal

2018-04-01

Rainfall thresholds express the minimum levels of rainfall that need to be reached or exceeded in order for landslides to occur in a particular area. They are a common tool in expressing the temporal portion of landslide hazard analysis. Numerous rainfall thresholds have been developed for different areas worldwide, however none of these are focused on landslides occurring on the engineered slopes on transport infrastructure networks. This paper uses empirical method to develop the rainfall thresholds for landslides on the Irish Rail network earthworks. For comparison, rainfall thresholds are also developed for natural terrain in Ireland. The results show that particular thresholds involving relatively low rainfall intensities are applicable for Ireland, owing to the specific climate. Furthermore, the comparison shows that rainfall thresholds for engineered slopes are lower than those for landslides occurring on the natural terrain. This has severe implications as it indicates that there is a significant risk involved when using generic weather alerts (developed largely for natural terrain) for infrastructure management, and showcases the need for developing railway and road specific rainfall thresholds for landslides.

Vanadium bioavailability and toxicity to soil microorganisms and plants.

PubMed

Larsson, Maja A; Baken, Stijn; Gustafsson, Jon Petter; Hadialhejazi, Golshid; Smolders, Erik

2013-10-01

Vanadium, V, is a redox-sensitive metal that in solution, under aerobic conditions, prevails as the oxyanion vanadate(V). There is little known regarding vanadium toxicity to soil biota, and the present study was set up to determine the toxicity of added vanadate to soil organisms and to investigate the relationship between toxicity and vanadium sorption in soils. Five soils with contrasting properties were spiked with 7 different doses (3.2-3200 mg V kg(-1)) of dissolved vanadate, and toxicity was measured with 2 microbial and 3 plant assays. The median effective concentration (EC50) thresholds of the microbial assays ranged from 28 mg added V kg(-1) to 690 mg added V kg(-1), and the EC50s in the plant assays ranged from 18 mg added V kg(-1) to 510 mg added V kg(-1). The lower thresholds were in the concentration range of the background vanadium in the untreated control soils (15-58 mg V kg(-1)). The vanadium toxicity to plants decreased with a stronger soil vanadium sorption strength. The EC50 values for plants expressed on a soil solution basis ranged from 0.8 mg V L(-1) to 15 mg V L(-1) and were less variable among soils than corresponding values based on total vanadium in soil. It is concluded that sorption decreases the toxicity of added vanadate and that soil solution vanadium is a more robust measure to determine critical vanadium concentrations across soils. © 2013 SETAC.

Hydraulic safety margins and air-seeding thresholds in roots, trunks, branches and petioles of four northern hardwood trees.

PubMed

Wason, Jay W; Anstreicher, Katherine S; Stephansky, Nathan; Huggett, Brett A; Brodersen, Craig R

2018-04-16

During drought, xylem sap pressures can approach or exceed critical thresholds where gas embolisms form and propagate through the xylem network, leading to systemic hydraulic dysfunction. The vulnerability segmentation hypothesis (VSH) predicts that low-investment organs (e.g. leaf petioles) should be more vulnerable to embolism spread compared to high-investment, perennial organs (e.g. trunks, stems), as a means of mitigating embolism spread and excessive negative pressures in the perennial organs. We tested this hypothesis by measuring air-seeding thresholds using the single-vessel air-injection method and calculating hydraulic safety margins in four northern hardwood tree species of the northeastern United States, in both saplings and canopy height trees, and at five points along the soil-plant-atmosphere continuum. Acer rubrum was the most resistant to air-seeding and generally supported the VSH. However, Fagus grandifolia, Fraxinus americana and Quercus rubra showed little to no variation in air-seeding thresholds across organ types within each species. Leaf-petiole xylem operated at water potentials close to or exceeding their hydraulic safety margins in all species, whereas roots, trunks and stems of A. rubrum, F. grandifolia and Q. rubra operated within their safety margins, even during the third-driest summer in the last 100 yr. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Toxicity of the molybdate anion in soil is partially explained by effects of the accompanying cation or by soil pH.

PubMed

Buekers, Jurgen; Mertens, Jelle; Smolders, Erik

2010-06-01

Previous studies have shown that toxicity of cationic trace metals in soil is partially confounded by effects of the accompanying anions. A similar assessment is reported here for toxicity of an oxyanion, i.e., molybdate (MoO(4) (2-)), the soil toxicity of which is relatively unexplored. Solubility and toxicity were compared between the soluble sodium molybdate (Na(2)MoO(4)) and the sparingly soluble molybdenum trioxide (MoO(3)). Confounding effects of salinity were excluded by referencing the Na(2)MoO(4) effect to that of sodium chloride (NaCl). The pH decrease from the acid MoO(3) amendment was equally referenced to a hydrochloric (HCl) treatment or a lime-controlled MoO(3) treatment. The concentrations of molybdenum (Mo) in soil solution or calcium chloride (CaCl(2)) 0.01 M extracts were only marginally affected by either MoO(3) or Na(2)MoO(4) as an Mo source after 10 to 13 days of equilibration. Effects of Mo on soil nitrification were fully confounded by associated changes in salinity or pH. Effects of Mo on growth of wheat seedlings (Triticum aestivum L) were more pronounced than those on nitrification, and toxicity thresholds were unaffected by the form of added Mo. The Mo thresholds for wheat growth were not confounded by pH or salinity at incipient toxicity. It is concluded that oxyanion toxicity might be confounded in relatively insensitive tests for which reference treatments should be included. Copyright 2010 SETAC.

Chemical fractionation of Cu and Zn in stormwater, roadway dust and stormwater pond sediments

USGS Publications Warehouse

Camponelli, Kimberly M.; Lev, Steven M.; Snodgrass, Joel W.; Landa, Edward R.; Casey, Ryan E.

2010-01-01

This study evaluated the chemical fractionation of Cu and Zn from source to deposition in a stormwater system. Cu and Zn concentrations and chemical fractionation were determined for roadway dust, roadway runoff and pond sediments. Stormwater Cu and Zn concentrations were used to generate cumulative frequency distributions to characterize potential exposure to pond-dwelling organisms. Dissolved stormwater Zn exceeded USEPA acute and chronic water quality criteria in approximately 20% of storm samples and 20% of the storm duration sampled. Dissolved Cu exceeded the previously published chronic criterion in 75% of storm samples and duration and exceeded the acute criterion in 45% of samples and duration. The majority of sediment Cu (92–98%) occurred in the most recalcitrant phase, suggesting low bioavailability; Zn was substantially more available (39–62% recalcitrant). Most sediment concentrations for Cu and Zn exceeded published threshold effect concentrations and Zn often exceeded probable effect concentrations in surface sediments.

Bioaccumulation and toxicity of selenium during a life-cycle exposure with desert pupfish (Cyprinodon macularius)

USGS Publications Warehouse

Besser, John M.; Brumbaugh, William G.; Papoulias, Diana M.; Ivey, Chris D.; Kunz, James L.; Annis, Mandy; Ingersoll, Christopher G.

2012-01-01

Populations of desert pupfish (Cyprinodon macularius; pupfish), a federally-listed endangered species, inhabit irrigation drains in the Imperial Valley agricultural area of southern California. These drains have varying degrees of selenium (Se) contamination of water, sediment, and aquatic biota. Published Se toxicity studies suggest that these levels of Se contamination may pose risk of chronic toxicity to Se-sensitive fish, but until recently there have been no studies of the chronic toxicity of Se to desert pupfish.A life-cycle Se exposure with pupfish was conducted to estimate dietary and tissue thresholds for toxic effects of Se on all life stages. The dietary exposure was based on live oligochaete worms (Lumbriculus variegatus) dosed with Se by a laboratory food chain based on selenized yeast. Oligochaetes readily accumulated Se from mixtures of selenized and control yeasts. The protocol for dosing oligochaetes for pupfish feeding studies included long-term (at least 28 days) feeding of a low-ration of yeast mixtures to large batches of oligochaetes. Oligochaetes were dosed at five Se levels in a 50-percent dilution series. Pupfish were simultaneously fed Se-dosed oligochaetes and exposed to a series of Se concentrations in water (consisting of 85 percent selenate and 15 percent selenite) to produce exposures that were consistent with Se concentrations and speciation in pupfish habitats. The nutritional characteristics of oligochaete diets were consistent across the range of oligochaete Se concentrations tested.The life-cycle exposure started with laboratory-cultured juvenile pupfish that were exposed to Se through sexual maturation and reproduction (150 days; F0 exposure). The Se exposure continued with eggs, larvae, and juveniles produced by Se-exposed parents (79 days; F1 exposure). Selenium exposure (water and diets), Se bioaccumulation (whole-body and eggs), and toxicity endpoints (juvenile and adult survival and growth; egg production and hatching success, larval survival and deformities) were documented throughout the life-cycle study.Selenium concentrations in water (as much as 52 micrograms per liter [μg/L]) and diets (as much as 53 micrograms per gram [μg/g], on a dry weight basis) bracketed concentrations reported in pupfish habitats. Juvenile F0 pupfish rapidly accumulated Se and bioaccumulation models indicated that pupfish had reached more than 97 percent of maximum whole-body Se concentrations by the time they reached reproductive maturity. Adult pupfish accumulated whole-body Se concentrations that averaged about 40 percent of those in the oligochaete diets. Selenium concentrations in eggs and F1 juveniles were similar to or slightly greater than Se concentrations in F0 adults. Juvenile F0 pupfish contained selenomethionine fractions (62–71 percent of whole-body Se) greater than the average reported for wild pupfish from the Imperial Valley (53 percent).Selenium exposure had minimal effects on survival or growth of juvenile and adult pupfish. There was evidence of toxic effects on pupfish in the highest Se treatment (Se–5), including reduced growth of F0 and F1 juvenile pupfish (17–21 percent less than controls) on some sampling dates. These growth reductions did not persist to subsequent sampling dates, but reduced growth of F1 pupfish in the Se–5 treatment was associated with reduced survival (12 percent less than controls).Egg production was greatest in the controls and decreased with increasing Se exposure, reaching a minimum (51 percent less than controls) in the Se–4 treatment, but egg production was reduced by only 24 percent in the Se–5 treatment, a lesser reduction than in other Se treatments except Se–1. There was no statistically significant overall effect of Se treatment on mean pupfish egg production, reflecting large variation among replicates and among sampling dates. However, comparisons of daily mean egg production for 23 sampling dates indicated that egg production in each of 5 Se treatments was significantly less than controls on multiple (3–7) sampling dates, but no mean for any Se treatment was significantly greater than controls on any date. Significant reductions in daily egg production occurred mainly during the middle of the study and egg production increased in several Se treatments during the final 2 weeks of the study. These results suggest that pupfish egg production, although a highly variable endpoint, was adversely affected by elevated Se exposure.Neither egg hatching success nor survival of F1 larvae indicated clear evidence of Se toxicity. Egg hatching success did not differ significantly among treatments, with means ranging from 84–91 percent. The frequency of morphological deformities (primarily spinal deformities) was greater in larvae 10 days post-fertilization (dpf) from a preliminary reproduction study than in older larvae (14 dpf) from the main reproduction study. The frequency of larval deformities was generally greater in Se treatments than controls, but mean frequencies did not differ significantly among treatments. Survival of F1 larvae to 21 dpf was not reduced significantly by parental Se exposure, but the Se–5 treatment had the lowest larval survival (84 percent), and lowest combined egg hatching and larval survival (76 percent).Results of the Se treatments indicate that pupfish were insensitive to Se toxicity through most of their life cycle. Consistent toxic effects on survival and growth of juvenile and adult pupfish (defined as at least 10 percent reduction compared to controls) occurred only in treatment Se–5, which had a mean dietary Se concentration of 52 μg/g and a mean pupfish whole-body Se concentration of 27 μg/g. These apparent toxicity thresholds for growth and survival rank among the least sensitive chronic Se toxicity values reported for nonreproductive endpoints in freshwater fish. Comparisons of these thresholds to surveys of Se concentrations in the Imperial Valley suggest that risks of Se toxicity are low in pupfish habitats. The dietary threshold was about twice as high as the greatest mean Se concentrations reported in midge larvae from seven sites in the Imperial Valley. Whole-body thresholds were greater than mean whole-body Se concentrations reported for field-collected pupfish from three sites and for the sailfin molly (Poecilia latipinna), a potential bioaccumulation surrogate for pupfish, from seven sites.Reduced egg production, although highly variable, was the most sensitive response of pupfish to Se exposure. Toxic effects on egg production (reductions of 24–51 percent relative to controls) occurred in the four highest Se treatments, corresponding to reproductive toxicity thresholds of 7.3 μg/g for Se in diet, 3.4 μg/g in pupfish (whole body), and 4.4 μg/g in pupfish eggs. These thresholds are substantially lower than published Se toxicity values for reproductive effects in other freshwater fish (for example, 17–24 μg/g in eggs). Reduced egg production has not been reported as a sensitive endpoint in Se toxicity studies, although abnormal ovarian development has been reported in Se-exposed fish, and reduced egg production has been reported as a sensitive response of other Cyprinodon pupfish to other environmental stressors.Selenium concentrations in tissues of pupfish, mollies, and diet items from Imperial Valley sites frequently exceeded concentrations associated with reduced pupfish egg production in the laboratory study. Reduced egg production may limit the ability of pupfish populations to persist and recover in Se-contaminated habitats in the Imperial Valley and elsewhere in their limited range. However, these apparent risks of Se toxicity are not supported by recent surveys of desert pupfish populations in the Imperial Valley. These surveys indicated that desert pupfish made up a small, but variable, component of fish communities in Imperial Valley habitats, including sites with increased levels of Se exposure, and that pupfish distribution and population density indicated no clear relationships with Se concentrations in diets or fish tissues. Additional studies could determine the role of egg production in the maintenance and recovery of desert pupfish populations in Se-contaminated habitats.

Assessing the nutrient intake of a low-carbohydrate, high-fat (LCHF) diet: a hypothetical case study design

PubMed Central

Zinn, Caryn; Rush, Amy; Johnson, Rebecca

2018-01-01

Objective The low-carbohydrate, high-fat (LCHF) diet is becoming increasingly employed in clinical dietetic practice as a means to manage many health-related conditions. Yet, it continues to remain contentious in nutrition circles due to a belief that the diet is devoid of nutrients and concern around its saturated fat content. This work aimed to assess the micronutrient intake of the LCHF diet under two conditions of saturated fat thresholds. Design In this descriptive study, two LCHF meal plans were designed for two hypothetical cases representing the average Australian male and female weight-stable adult. National documented heights, a body mass index of 22.5 to establish weight and a 1.6 activity factor were used to estimate total energy intake using the Schofield equation. Carbohydrate was limited to <130 g, protein was set at 15%–25% of total energy and fat supplied the remaining calories. One version of the diet aligned with the national saturated fat guideline threshold of <10% of total energy and the other included saturated fat ad libitum. Primary outcomes The primary outcomes included all micronutrients, which were assessed using FoodWorks dietary analysis software against national Australian/New Zealand nutrient reference value (NRV) thresholds. Results All of the meal plans exceeded the minimum NRV thresholds, apart from iron in the female meal plans, which achieved 86%–98% of the threshold. Saturated fat intake was logistically unable to be reduced below the 10% threshold for the male plan but exceeded the threshold by 2 g (0.6%). Conclusion Despite macronutrient proportions not aligning with current national dietary guidelines, a well-planned LCHF meal plan can be considered micronutrient replete. This is an important finding for health professionals, consumers and critics of LCHF nutrition, as it dispels the myth that these diets are suboptimal in their micronutrient supply. As with any diet, for optimal nutrient achievement, meals need to be well formulated. PMID:29439004

301-15 East Illinois St, December 2017, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 800 cpm to a maximum of 2,800cpm shielded.

48 CFR 8.405-2 - Ordering procedures for services requiring a statement of work.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... (3) For proposed orders exceeding the maximum order threshold or when establishing a BPA. In addition... is reasonable. Place the order, or establish the BPA, with the schedule contractor that represents...

48 CFR 26.304 - Solicitation provision.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PROGRAMS OTHER SOCIOECONOMIC PROGRAMS Historically Black Colleges and Universities and Minority Institutions 26.304 Solicitation provision. Insert the provision at 52.226-2, Historically Black College or University and Minority Institution Representation, in solicitations exceeding the micro-purchase threshold...

335 E. Erie, January 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 4,900 cpm to a maximum of 10,200cpm unshielded.

215 E. Grand Ave, December 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 6,800 cpm to a maximum of 7,200cpm unshielded.

ProUCL Version 4.0 Technical Guide

EPA Science Inventory

Statistical inference, including both estimation and hypotheses testing approaches, is routinely used to: estimate environmental parameters of interest, such as exposure point concentration (EPC) terms, not-to-exceed values, and background level threshold values (BTVs) for contam...

243 E. Ontario Street - Water, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,400 cpm to a maximum of 2,600cpm shielded.

224 E Ontario, February 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 6,200 cpm to a maximum of 7,500cpm unshielded.

54-63 East Ohio St., Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 2,000 cpm to a maximum of 2,300cpm shielded.

225 E. Grand Ave, Septmber 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 5,300 cpm to a maximum of 9,700cpm unshielded.

243 E. Ontario Street - Sewer, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated, and ranged from a minimum of 1,100 cpm to a maximum of 3,600cpm shielded.

226-237 E. Ontario, April 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements did not exceed the field instrument threshold equivalent to the USEPA removal actionlevel and ranged from a minimum of 6,000 cpm to a maximum of approximately 9,000 cpm unshielded.

228 E. Ontario, February 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 5,400 cpm to a maximum of 10,000cpm unshielded.

330-334 E. Ontario, April 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurement did not exceed the field instrument threshold equivalent to the USEPA removal actionlevel and ranged from a minimum of 5,700 cpm to a maximum of approximately 13,100 cpm unshielded.

48 CFR 26.304 - Solicitation provision.

Code of Federal Regulations, 2014 CFR

2014-10-01

... PROGRAMS OTHER SOCIOECONOMIC PROGRAMS Historically Black Colleges and Universities and Minority Institutions 26.304 Solicitation provision. Insert the provision at 52.226-2, Historically Black College or University and Minority Institution Representation, in solicitations exceeding the micro-purchase threshold...

48 CFR 26.304 - Solicitation provision.

Code of Federal Regulations, 2013 CFR

2013-10-01

... PROGRAMS OTHER SOCIOECONOMIC PROGRAMS Historically Black Colleges and Universities and Minority Institutions 26.304 Solicitation provision. Insert the provision at 52.226-2, Historically Black College or University and Minority Institution Representation, in solicitations exceeding the micro-purchase threshold...

48 CFR 26.304 - Solicitation provision.

Code of Federal Regulations, 2012 CFR

2012-10-01

... PROGRAMS OTHER SOCIOECONOMIC PROGRAMS Historically Black Colleges and Universities and Minority Institutions 26.304 Solicitation provision. Insert the provision at 52.226-2, Historically Black College or University and Minority Institution Representation, in solicitations exceeding the micro-purchase threshold...

Fault detection and diagnosis for refrigerator from compressor sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keres, Stephen L.; Gomes, Alberto Regio; Litch, Andrew D.

A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identifiedmore » if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.« less

Mining Stable Roles in RBAC

NASA Astrophysics Data System (ADS)

Colantonio, Alessandro; di Pietro, Roberto; Ocello, Alberto; Verde, Nino Vincenzo

In this paper we address the problem of generating a candidate role-set for an RBAC configuration that enjoys the following two key features: it minimizes the administration cost; and, it is a stable candidate role-set. To achieve these goals, we implement a three steps methodology: first, we associate a weight to roles; second, we identify and remove the user-permission assignments that cannot belong to a role that have a weight exceeding a given threshold; third, we restrict the problem of finding a candidate role-set for the given system configuration using only the user-permission assignments that have not been removed in the second step—that is, user-permission assignments that belong to roles with a weight exceeding the given threshold. We formally show—proof of our results are rooted in graph theory—that this methodology achieves the intended goals. Finally, we discuss practical applications of our approach to the role mining problem.

California sea otter (Enhydra lutris nereis) census results, Spring 2017

USGS Publications Warehouse

Tinker, M. Tim; Hatfield, Brian B.

2017-09-29

The 2017 census of southern sea otters (Enhydra lutris nereis) was conducted between late April and early July along the mainland coast of central California and in April at San Nicolas Island in southern California. The 3-year average of combined counts from the mainland range and San Nicolas Island was 3,186, down by 86 sea otters from the previous year. This is the second year that the official index has exceeded 3,090, the Endangered Species Act delisting threshold identified in the U.S. Fish and Wildlife Service’s Southern Sea Otter Recovery Plan (the threshold would need to be exceeded for 3 consecutive years before delisting consideration). The 5-year average trend in abundance, including both the mainland range and San Nicolas Island populations, remains positive at 2.3 percent per year. Continuing lack of growth in the range peripheries likely explains the cessation of range expansion.

Replenishing data descriptors in a DMA injection FIFO buffer

DOEpatents

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Cernohous, Bob R [Rochester, MN; Heidelberger, Philip [Cortlandt Manor, NY; Kumar, Sameer [White Plains, NY; Parker, Jeffrey J [Rochester, MN

2011-10-11

Methods, apparatus, and products are disclosed for replenishing data descriptors in a Direct Memory Access (`DMA`) injection first-in-first-out (`FIFO`) buffer that include: determining, by a messaging module on an origin compute node, whether a number of data descriptors in a DMA injection FIFO buffer exceeds a predetermined threshold, each data descriptor specifying an application message for transmission to a target compute node; queuing, by the messaging module, a plurality of new data descriptors in a pending descriptor queue if the number of the data descriptors in the DMA injection FIFO buffer exceeds the predetermined threshold; establishing, by the messaging module, interrupt criteria that specify when to replenish the injection FIFO buffer with the plurality of new data descriptors in the pending descriptor queue; and injecting, by the messaging module, the plurality of new data descriptors into the injection FIFO buffer in dependence upon the interrupt criteria.

System and method for optically locating microchannel positions

DOEpatents

Brewer, Laurence R.; Kimbrough, Joseph; Balch, Joseph; Davidson, J. Courtney

2001-01-01

A system and method is disclosed for optically locating a microchannel position. A laser source generates a primary laser beam which is directed at a microchannel plate. The microchannel plates include microchannels at various locations. A back-reflectance beam detector receives a back-reflected beam from the plate. The back-reflected beam is generated when the primary beam reflects off of the plate. A photodiode circuit generates a trigger signal when the back-reflected beam exceeds a predetermined threshold, indicating a presence of the microchannel. The method of the present invention includes the steps of generating a primary beam, directing the primary beam to a plate containing a microchannel, receiving from the plate a back-reflected beam generated in response to the primary beam, and generating a trigger signal when the back-reflected beam exceeds a predetermined threshold which corresponds to a presence of the microchannel.

Threshold and resilience management of coupled urbanization and water environmental system in the rapidly changing coastal region.

PubMed

Li, Yangfan; Li, Yi; Wu, Wei

2016-01-01

The concept of thresholds shows important implications for environmental and resource management. Here we derived potential landscape thresholds which indicated abrupt changes in water quality or the dividing points between exceeding and failing to meet national surface water quality standards for a rapidly urbanizing city on the Eastern Coast in China. The analysis of landscape thresholds was based on regression models linking each of the seven water quality variables to each of the six landscape metrics for this coupled land-water system. We found substantial and accelerating urban sprawl at the suburban areas between 2000 and 2008, and detected significant nonlinear relations between water quality and landscape pattern. This research demonstrated that a simple modeling technique could provide insights on environmental thresholds to support more-informed decision making in land use, water environmental and resilience management. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sliding mode control of outbreaks of emerging infectious diseases.

PubMed

Xiao, Yanni; Xu, Xiaxia; Tang, Sanyi

2012-10-01

This paper proposes and analyzes a mathematical model of an infectious disease system with a piecewise control function concerning threshold policy for disease management strategy. The proposed models extend the classic models by including a piecewise incidence rate to represent control or precautionary measures being triggered once the number of infected individuals exceeds a threshold level. The long-term behaviour of the proposed non-smooth system under this strategy consists of the so-called sliding motion-a very rapid switching between application and interruption of the control action. Model solutions ultimately approach either one of two endemic states for two structures or the sliding equilibrium on the switching surface, depending on the threshold level. Our findings suggest that proper combinations of threshold densities and control intensities based on threshold policy can either preclude outbreaks or lead the number of infected to a previously chosen level.

AREA RADIATION MONITOR

DOEpatents

Manning, F.W.; Groothuis, S.E.; Lykins, J.H.; Papke, D.M.

1962-06-12

S>An improved area radiation dose monitor is designed which is adapted to compensate continuously for background radiation below a threshold dose rate and to give warning when the dose integral of the dose rate of an above-threshold radiation excursion exceeds a selected value. This is accomplished by providing means for continuously charging an ionization chamber. The chamber provides a first current proportional to the incident radiation dose rate. Means are provided for generating a second current including means for nulling out the first current with the second current at all values of the first current corresponding to dose rates below a selected threshold dose rate value. The second current has a maximum value corresponding to that of the first current at the threshold dose rate. The excess of the first current over the second current, which occurs above the threshold, is integrated and an alarm is given at a selected integrated value of the excess corresponding to a selected radiation dose. (AEC)

High speed point derivative microseismic detector

DOEpatents

Uhl, J.E.; Warpinski, N.R.; Whetten, E.B.

1998-06-30

A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves. 9 figs.

High speed point derivative microseismic detector

DOEpatents

Uhl, James Eugene; Warpinski, Norman Raymond; Whetten, Ernest Blayne

1998-01-01

A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves.

Water quality and bed sediment quality in the Albemarle Sound, North Carolina, 2012–14

USGS Publications Warehouse

Moorman, Michelle C.; Fitzgerald, Sharon A.; Gurley, Laura N.; Rhoni-Aref, Ahmed; Loftin, Keith A.

2017-01-23

The Albemarle Sound region was selected in 2012 as one of two demonstration sites in the Nation to test and improve the design of the National Water Quality Monitoring Council’s National Monitoring Network (NMN) for U.S. Coastal Waters and Tributaries. The goal of the NMN for U.S. Coastal Waters and Tributaries is to provide information about the health of our oceans, coastal ecosystems, and inland influences on coastal waters for improved resource management. The NMN is an integrated, multidisciplinary, and multi-organizational program using multiple sources of data and information to augment current monitoring programs.This report presents and summarizes selected water-quality and bed sediment-quality data collected as part of the demonstration project conducted in two phases. The first phase was an occurrence and distribution study to assess nutrients, metals, pesticides, cyanotoxins, and phytoplankton communities in the Albemarle Sound during the summer of 2012 at 34 sites in Albemarle Sound, nearby sounds, and various tributaries. The second phase consisted of monthly sampling over a year (March 2013 through February 2014) to assess seasonality in a more limited set of constituents including nutrients, cyanotoxins, and phytoplankton communities at a subset (eight) of the sites sampled in the first phase. During the summer of 2012, few constituent concentrations exceeded published water-quality thresholds; however, elevated levels of chlorophyll a and pH were observed in the northern embayments and in Currituck Sound. Chlorophyll a, and metals (copper, iron, and zinc) were detected above a water-quality threshold. The World Health Organization provisional guideline based on cyanobacterial density for high recreational risk was exceeded in approximately 50 percent of water samples collected during the summer of 2012. Cyanobacteria capable of producing toxins were present, but only low levels of cyanotoxins below human health benchmarks were detected. Finally, 12 metals in surficial bed sediments were detected at levels above a published sediment-quality threshold. These metals included chromium, mercury, copper, lead, arsenic, nickel, and cadmium. Sites with several metal concentrations above the respective thresholds had relatively high concentrations of organic carbon or fine sediment (silt plus clay), or both and were predominantly located in the western and northwestern parts of the Albemarle Sound.Results from the second phase were generally similar to those of the first in that relatively few constituents exceeded a water-quality threshold, both pH and chlorophyll a were detected above the respective water-quality thresholds, and many of these elevated concentrations occurred in the northern embayments and in Currituck Sound. In contrast to the results from phase one, the cyanotoxin, microcystin was detected at more than 10 times the water-quality threshold during a phytoplankton bloom on the Chowan River at Mount Gould, North Carolina in August of 2013. This was the only cyanotoxin concentration measured during the entire study that exceeded a respective water-quality threshold.The information presented in this report can be used to improve understanding of water-quality conditions in the Albemarle Sound, particularly when evaluating causal and response variables that are indicators of eutrophication. In particular, this information can be used by State agencies to help develop water-quality criteria for nutrients, and to understand factors like cyanotoxins that may affect fisheries and recreation in the Albemarle Sound region.

Modification of turbulence and turbulent transport associated with a confinement transition in LAPD

NASA Astrophysics Data System (ADS)

Carter, Troy

2009-11-01

Azimuthal flow is driven in the edge of the Large Plasma Device (LAPD) through biasing a section of the vacuum vessel relative to the plasma source cathode. As the applied bias exceeds a threshold, a transition in radial particle confinement is observed, evidenced by a dramatic steepening in the density profile, similar to the L- to H-mode transition in toroidal confinement devices. The threshold behavior and dynamic behavior of radial transport is related to flow penetration and the degree of spatial overlap between the flow shear and density gradient profiles. An investigation of the changes in turbulence and turbulent particle transport associated with the confinement transition is presented. Two-dimensional cross-correlation measurements show that the spatial coherence of edge turbulence in LAPD changes significantly with biasing. The azimuthal correlation in the turbulence increases dramatically, while the radial correlation length is little altered. Turbulent amplitude is reduced at the transition, particularly in electric field fluctuations, but the dominant change observed is in the cross-phase between density and electric field fluctuations. The changes in cross-phase lead to a suppression and then apparent reversal of turbulent particle flux as the threshold is exceeded.

A new risk assessment approach for the prioritization of 500 classical and emerging organic microcontaminants as potential river basin specific pollutants under the European Water Framework Directive.

PubMed

von der Ohe, Peter Carsten; Dulio, Valeria; Slobodnik, Jaroslav; De Deckere, Eric; Kühne, Ralph; Ebert, Ralf-Uwe; Ginebreda, Antoni; De Cooman, Ward; Schüürmann, Gerrit; Brack, Werner

2011-05-01

Given the huge number of chemicals released into the environment and existing time and budget constraints, there is a need to prioritize chemicals for risk assessment and monitoring in the context of the European Union Water Framework Directive (EU WFD). This study is the first to assess the risk of 500 organic substances based on observations in the four European river basins of the Elbe, Scheldt, Danube and Llobregat. A decision tree is introduced that first classifies chemicals into six categories depending on the information available, which allows water managers to focus on the next steps (e.g. derivation of Environmental Quality Standards (EQS), improvement of analytical methods, etc.). The priority within each category is then evaluated based on two indicators, the Frequency of Exceedance and the Extent of Exceedance of Predicted No-Effect Concentrations (PNECs). These two indictors are based on maximum environmental concentrations (MEC), rather than the commonly used statistically based averages (Predicted Effect Concentration, PEC), and compared to the lowest acute-based (PNEC(acute)) or chronic-based thresholds (PNEC(chronic)). For 56% of the compounds, PNECs were available from existing risk assessments, and the majority of these PNECs were derived from chronic toxicity data or simulated ecosystem studies (mesocosm) with rather low assessment factors. The limitations of this concept for risk assessment purposes are discussed. For the remainder, provisional PNECs (P-PNECs) were established from read-across models for acute toxicity to the standard test organisms Daphnia magna, Pimephales promelas and Selenastrum capricornutum. On the one hand, the prioritization revealed that about three-quarter of the 44 substances with MEC/PNEC ratios above ten were pesticides. On the other hand, based on the monitoring data used in this study, no risk with regard to the water phase could be found for eight of the 41 priority substances, indicating a first success of the implementation of the WFD in the investigated river basins. Copyright © 2011 Elsevier B.V. All rights reserved.

A study of the threshold method utilizing raingage data

NASA Technical Reports Server (NTRS)

Short, David A.; Wolff, David B.; Rosenfeld, Daniel; Atlas, David

1993-01-01

The threshold method for estimation of area-average rain rate relies on determination of the fractional area where rain rate exceeds a preset level of intensity. Previous studies have shown that the optimal threshold level depends on the climatological rain-rate distribution (RRD). It has also been noted, however, that the climatological RRD may be composed of an aggregate of distributions, one for each of several distinctly different synoptic conditions, each having its own optimal threshold. In this study, the impact of RRD variations on the threshold method is shown in an analysis of 1-min rainrate data from a network of tipping-bucket gauges in Darwin, Australia. Data are analyzed for two distinct regimes: the premonsoon environment, having isolated intense thunderstorms, and the active monsoon rains, having organized convective cell clusters that generate large areas of stratiform rain. It is found that a threshold of 10 mm/h results in the same threshold coefficient for both regimes, suggesting an alternative definition of optimal threshold as that which is least sensitive to distribution variations. The observed behavior of the threshold coefficient is well simulated by assumption of lognormal distributions with different scale parameters and same shape parameters.

Genetic variation in threshold reaction norms for alternative reproductive tactics in male Atlantic salmon, Salmo salar.

PubMed

Piché, Jacinthe; Hutchings, Jeffrey A; Blanchard, Wade

2008-07-07

Alternative reproductive tactics may be a product of adaptive phenotypic plasticity, such that discontinuous variation in life history depends on both the genotype and the environment. Phenotypes that fall below a genetically determined threshold adopt one tactic, while those exceeding the threshold adopt the alternative tactic. We report evidence of genetic variability in maturation thresholds for male Atlantic salmon (Salmo salar) that mature either as large (more than 1 kg) anadromous males or as small (10-150 g) parr. Using a common-garden experimental protocol, we find that the growth rate at which the sneaker parr phenotype is expressed differs among pure- and mixed-population crosses. Maturation thresholds of hybrids were intermediate to those of pure crosses, consistent with the hypothesis that the life-history switch points are heritable. Our work provides evidence, for a vertebrate, that thresholds for alternative reproductive tactics differ genetically among populations and can be modelled as discontinuous reaction norms for age and size at maturity.

Regional rainfall thresholds for landslide occurrence using a centenary database

NASA Astrophysics Data System (ADS)

Vaz, Teresa; Luís Zêzere, José; Pereira, Susana; Cruz Oliveira, Sérgio; Garcia, Ricardo A. C.; Quaresma, Ivânia

2018-04-01

This work proposes a comprehensive method to assess rainfall thresholds for landslide initiation using a centenary landslide database associated with a single centenary daily rainfall data set. The method is applied to the Lisbon region and includes the rainfall return period analysis that was used to identify the critical rainfall combination (cumulated rainfall duration) related to each landslide event. The spatial representativeness of the reference rain gauge is evaluated and the rainfall thresholds are assessed and calibrated using the receiver operating characteristic (ROC) metrics. Results show that landslide events located up to 10 km from the rain gauge can be used to calculate the rainfall thresholds in the study area; however, these thresholds may be used with acceptable confidence up to 50 km from the rain gauge. The rainfall thresholds obtained using linear and potential regression perform well in ROC metrics. However, the intermediate thresholds based on the probability of landslide events established in the zone between the lower-limit threshold and the upper-limit threshold are much more informative as they indicate the probability of landslide event occurrence given rainfall exceeding the threshold. This information can be easily included in landslide early warning systems, especially when combined with the probability of rainfall above each threshold.

The game of making decisions under uncertainty: How sure must one be?

NASA Astrophysics Data System (ADS)

Werner, Micha; Verkade, Jan; Wetterhall, Fredrik; van Andel, Schalk-Jan; Ramos, Maria-Helena

2016-04-01

Probabilistic hydrometeorological forecasting is now widely accepted to be more skillful than deterministic forecasts, and is increasingly being integrated into operational practice. Provided they are reliable and unbiased, probabilistic forecasts have the advantage that they give decision maker not only the forecast value, but also the uncertainty associated to that prediction. Though that information provides more insight, it does now leave the forecaster/decision maker with the challenge of deciding at what level of probability of a threshold being exceeded the decision to act should be taken. According to the cost-loss theory, that probability should be related to the impact of the threshold being exceeded. However, it is not entirely clear how easy it is for decision makers to follow that rule, even when the impact of a threshold being exceeded, and the actions to choose from are known. To continue the tradition in the "Ensemble Hydrometeorological Forecast" session, we will address the challenge of making decisions based on probabilistic forecasts through a game to be played with the audience. We will explore how decisions made differ depending on the known impacts of the forecasted events. Participants will be divided into a number of groups with differing levels of impact, and will be faced with a number of forecast situations. They will be asked to make decisions and record the consequence of those decisions. A discussion of the differences in the decisions made will be presented at the end of the game, with a fuller analysis later posted on the HEPEX web site blog (www.hepex.org).

Agricultural sources of contaminants of emerging concern and adverse health effects on freshwater fish

USGS Publications Warehouse

Tillitt, Donald E.; Buxton, Herbert T.

2011-01-01

Agricultural contaminants of emerging concern (CECs) are generally thought of as certain classes of chemicals associated with animal feeding and production facilities. Veterinary pharmaceuticals used in animal food production systems represent one of the largest groups of CECs. In our review, we discuss the extensive increase in use of antibiotics in animal feeding operations (AFOs) around the world. AFOs are a major consumer of antibiotics and other veterinary pharmaceuticals and over the past decade there has been growing information on the occurrence, release, and fate of CECs from animal food production operations, including the application of pharmaceutical-containing manure to agricultural fields and releases from waste lagoons. Concentrations of CECs in surface and ground water in proximity to AFOs correspond to their presence in the AFO wastes. In many cases, the environmental concentrations of agriculturally-derived CECs are below toxicity thresholds. Hormones and hormone replacement compounds are a notable exception, where chemical concentrations near AFOs can exceed concentrations known to cause adverse effects on endocrine-related functions in fish. In addition, some agricultural pesticides, once thought to be safe to non-target organisms, have demonstrated endocrine-related effects that may pose threats to fish populations in agricultural regions. That is, we have pesticides with emerging concerns, thus, the concern is emerging and not necessarily the chemical. In this light, one must consider certain agricultural pesticides to be included in the list of CECs. Even though agricultural pesticides are routinely evaluated in regulatory testing schemes which have been used for decades, the potential hazards of some pesticides have only recently been emerging. Emerging concerns of pesticides in fish include interference with hormone signaling pathways; additive (or more than additive) effects from pesticide mixtures; and adverse population-level effects at concentrations below predicted toxicity thresholds. Consequently, there is a need to evaluate the environmental concerns related to pesticide exposures to fish populations based on current biological and toxicological techniques. This presentation reviews some of the agricultural chemicals that have emerged as contaminants of concern and potentially threaten fish populations in agricultural watersheds.

Robot gripper

NASA Technical Reports Server (NTRS)

Webb, Winston S. (Inventor)

1987-01-01

An electronic force-detecting robot gripper for gripping objects and attaching to an external robot arm is disclosed. The gripper comprises motor apparatus, gripper jaws, and electrical circuits for driving the gripper motor and sensing the amount of force applied by the jaws. The force applied by the jaws is proportional to a threshold value of the motor current. When the motor current exceeds the threshold value, the electrical circuits supply a feedback signal to the electrical control circuit which, in turn, stops the gripper motor.

Spacecraft momentum unloading using controlled magnetic torques

NASA Technical Reports Server (NTRS)

Linder, David M. (Inventor); Goodzeit, Neil E. (Inventor); Schwarzschild, Marc (Inventor)

1992-01-01

A method for maintaining the attitude of a three-axis controlled satellite by use of magnetic torquers includes using magnetometers for measuring the direction of the ambient geomagnetic field. The direction of the net reaction wheel momentum is also determined. The angle between the direction of the geomagnetic field and the net reaction wheel momentum is determined. The angle is compared with a threshold value. Magnetic torquer power consumption is reduced by operating the magnetic torquers only when the angle exceeds the threshold value.

On the estimation of risk associated with an attenuation prediction

NASA Technical Reports Server (NTRS)

Crane, R. K.

1992-01-01

Viewgraphs from a presentation on the estimation of risk associated with an attenuation prediction is presented. Topics covered include: link failure - attenuation exceeding a specified threshold for a specified time interval or intervals; risk - the probability of one or more failures during the lifetime of the link or during a specified accounting interval; the problem - modeling the probability of attenuation by rainfall to provide a prediction of the attenuation threshold for a specified risk; and an accounting for the inadequacy of a model or models.

Hyperspectral image analysis for plant stress detection

USDA-ARS?s Scientific Manuscript database

Abiotic and disease-induced stress significantly reduces plant productivity. Automated on-the-go mapping of plant stress allows timely intervention and mitigating of the problem before critical thresholds are exceeded, thereby, maximizing productivity. A hyperspectral camera analyzed the spectral ...

479 N Columbus Dr, March 2012, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

field gamma measurements did not exceed the respective field instrument threshold values previously stated and ranged from aminimum of 4,500 cpm unshielded to a maximum of 5,700 cpm shielded in the bottom of the excavation.

545 N McClurg Ct, February 2015, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 5,700 cpm to a maximum of 13,500cpm unshielded.

600 N McClurg Ct, April 2012, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements did not exceed the respective field instrument threshold values previously stated andranged from 3,400 to 9,500 cpm unshielded with a maximum of 4,500 cpm shielded in the bottom of theexcavation

300 East Randolph, December 2010, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

Field gamma measurements within the excavation and the spoil materials generated during theexcavation process did not exceed the respective threshold values previously stated and generallyranged from 4,050 cpm to 9,690 cpm with the unshielded probe.

356 E Grand, July 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 5,000 cpm to amaximum of 9,600 cpm unshielded.

362-363 E. Ontario, April 2012, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

field gamma measurements did not exceed the respective field instrument threshold values previously stated andranged from 3,400 to 9,500 cpm unshielded with a maximum of 4,500 cpm shielded in the bottom of theexcavation.

237 E Ontario, July 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavations and of the spoil during the excavation process didnot exceed the instrument threshold previously stated and ranged from a minimum of 8,600 cpm to amaximum of 9,500 cpm unshielded.

226-228 E Ontario St, December 2014, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theunshielded instrument threshold previously stated and ranged from a minimum of 6,200 cpm to amaximum of 8,800 cpm unshielded.

48 CFR 1532.003 - Simplified acquisition procedures financing.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Simplified acquisition procedures financing. 1532.003 Section 1532.003 Federal Acquisition Regulations System ENVIRONMENTAL.... (c) Procedures for purchases exceeding micropurchase threshold. Contracting officers must secure...

48 CFR 1532.003 - Simplified acquisition procedures financing.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Simplified acquisition procedures financing. 1532.003 Section 1532.003 Federal Acquisition Regulations System ENVIRONMENTAL.... (c) Procedures for purchases exceeding micropurchase threshold. Contracting officers must secure...

48 CFR 1532.003 - Simplified acquisition procedures financing.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Simplified acquisition procedures financing. 1532.003 Section 1532.003 Federal Acquisition Regulations System ENVIRONMENTAL.... (c) Procedures for purchases exceeding micropurchase threshold. Contracting officers must secure...

48 CFR 1532.003 - Simplified acquisition procedures financing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Simplified acquisition procedures financing. 1532.003 Section 1532.003 Federal Acquisition Regulations System ENVIRONMENTAL.... (c) Procedures for purchases exceeding micropurchase threshold. Contracting officers must secure...

380 E. North Water St, April 2016, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The field gamma measurements within the excavation during the excavation process did not exceed theinstrument threshold previously stated and ranged from a minimum of 6,800 cpm to a maximum of 12,100cpm unshielded.

77 FR 55222 - Notice of Availability of the Draft Resource Management Plan Amendment and the Draft...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-07

... development (e.g., year-round drilling instead of timing limitations if development does not exceed a particular threshold) and emphasizes conservation and protection of other resources by limiting the duration...