Impacts of dredged-material disposal on the coastal soft-bottom macrofauna, Saronikos Gulf, Greece.

PubMed

Katsiaras, N; Simboura, N; Tsangaris, C; Hatzianestis, I; Pavlidou, A; Kapsimalis, V

2015-03-01

Dredged sediments derived by the low course and estuary of the metropolitan river of Athens (Kifissos River) were dumped every day for 21 months to an open-sea site in the Saronikos Gulf. The spoil-ground and surrounding area was monitored prior, during and post to dumping for 24 months, over 6-month intervals. Dumping significantly changed the granulometry of the pre-existing superficial sediments to finer-grained only in the spoil ground and increased the sediment contamination load (aliphatic, polycyclic aromatic hydrocarbons and heavy metals) throughout the study area. Microtox® SPT showed that sediment toxicity levels were high at almost all sampling stations. During dumping, burial of natural soft-bottom habitats degraded severely the communities of the spoil-ground resulting in an almost azoic state, as well as significantly declined the species number and abundance of benthic communities in locations up to 3.2 km away from the spoil-ground, due to dispersion of the spoil and smothering. Benthic indices on the surrounding sites were significantly correlated with hydrocarbon concentrations and sediment toxicity levels. Post to dumping, the macrofauna communities of the spoil-ground were still significantly degraded, but the surrounding areas showed patterns of recovery. However, the high concentrations of aliphatic, polycyclic aromatic hydrocarbons and levels of toxicity persisted in the sediments after the ceasing of dumping operations in the study area, implying the ecological hazard imposed on the area. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of the effect of organic pro-degradant concentration in polypropylene exposed to the natural ageing

NASA Astrophysics Data System (ADS)

Montagna, L. S.; Catto, A. L.; Rossini, K.; Forte, M. M. C.; Santana, R. M. C.

2014-05-01

The production and consumption of plastics in the last decade has recorded a remarkable increase in the scientific and industrial interest in environmentally degradable polymer (EDPs). Polymers wastes are deposited improperly, such as dumps, landfills, rivers and seas, causing a serious problem by the accumulation in the environment. The abiotic processes, like the photodegradation, are the most efficient occurring in the open environmental, where the polymers undergo degradation from the action of sunlight that result from direct exposure to solar radiation, however depend of the type of chemical ageing, which is the principal component of climatic ageing. The subject of this work is to study the influence of concentration of organic pro-degradant (1, 2 and 3 % w/w) in the polypropylene (PP) exposed in natural ageing. PP samples with and without the additive were processed in plates square form, obtained by thermal compression molding (TCM) using a press at 200°C under 2 tons for 5 min, and then were exposed at natural ageing during 120 days. The presence of organic additive influenced on PP degradability, this fact was assessed by changes in the thermal and morphology properties of the samples after 120 days of natural ageing. Scanning Electronic Microscopy (SEM) results of the morphological surface of the modified PP samples showed greater degradation photochemical oxidative when compared to neat PP, due to increase of rugosity and formation of microvoids. PP samples with different pro-degradant concentration under natural ageing presented a degree of crystallinity, obtained by Differential Scanning Calorimeter (DSC) increases in comparing the neat PP.

Soil contamination by brominated flame retardants in open waste dumping sites in Asian developing countries.

PubMed

Eguchi, Akifimi; Isobe, Tomohiko; Ramu, Karri; Tue, Nguyen Minh; Sudaryanto, Agus; Devanathan, Gnanasekaran; Viet, Pham Hung; Tana, Rouch Seang; Takahashi, Shin; Subramanian, Annamalai; Tanabe, Shinsuke

2013-03-01

In Asian developing countries, large amounts of municipal wastes are dumped into open dumping sites each day without adequate management. This practice may cause several adverse environmental consequences and increase health risks to local communities. These dumping sites are contaminated with many chemicals including brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). BFRs may be released into the environment through production processes and through the disposal of plastics and electronic wastes that contain them. The purpose of this study was to elucidate the status of BFR pollution in municipal waste dumping sites in Asian developing countries. Soil samples were collected from six open waste dumping sites and five reference sites in Cambodia, India, Indonesia, Malaysia, and Vietnam from 1999 to 2007. The results suggest that PBDEs are the dominant contaminants in the dumping sites in Asian developing countries, whereas HBCD contamination remains low. Concentrations of PBDEs and HBCDs ranged from ND to 180 μg/kg dry wt and ND to 1.4 μg/kg dry wt, respectively, in the reference sites and from 0.20 to 430 μg/kg dry wt and ND to 2.5 μg/kg dry wt, respectively, in the dumping sites. Contamination levels of PBDEs in Asian municipal dumping sites were comparable with those reported from electronic waste dismantling areas in Pearl River delta, China. Copyright © 2012 Elsevier Ltd. All rights reserved.

Geology beneath and beside the notorious Payatas open dump, Metro Manila, Philippines

NASA Astrophysics Data System (ADS)

Tomarong, C.; Arcilla, C.; de Sales, L.; Chua, S.; Garcia, E.; Pamintuan, G.

2003-04-01

With a minimum of 6000 tonnes/day municipal waste output, and with NO existing operational sanitary landfill and with incineration illegal, Metro Manila has a very serious solid waste disposal problem. Unsorted municipal waste are being piled in open dumps, the most notorious of which is the Payatas open dump. A recent, tragic garbage-slide in this open dump caused dozens of deaths, news of which were broadcast internationally. Political expediency laced with a lot of corruption, rather than sound science, was the main basis for selecting this site as an open dump. As an example, this dump is situated < 1 km from the Novaliches Watershed Reservation, one of the main sources of drinking water for Metro Manila’s 12 million population! Yet, after dumping operations that have lasted more than 10 years, only recently were the preliminary geologic studies begun. Payatas is not a designed landfill and its untreated leachate is openly polluting the headwaters of the Marikina and Pasig Rivers. In addition, during the summer months, there is always the constant threat of fire due to methane induced burning from the dump, aside from the aerial pollution from dioxins and furans derived from incomplete combustion of municipal solid waste. With limited funding from the Quezon City government, a feasibility study was conducted to assess the methane generation potential of Payatas. This interdisciplinary study comprised bedrock geological studies, topographic mapping of the dump, drilling of the dump to obtain stratigraphic solid waste samples for waste characterization, laying of horizontal methane and dewatering pipes, and preliminary methane flow studies. The waste characterization has highlighted the unusually high organic (especially yard waste) component of the solid waste dumped at Payatas. Waste characterization shows that a significant portion of the waste is plastics. Several cross-sections cut across the dump show that the side slopes of the dump are on the average steeper than the pre-dump slopes. The “bedrock” of the Payatas dump are conglomerate members of the Pleistocene volcaniclastic Guadualupe Formation. Studies are still to be done on the extent of pollution on surface and groundwater in the Payatas environs.

Evaluation of the effect of organic pro-degradant concentration in polypropylene exposed to the natural ageing

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

Montagna, L. S., E-mail: larissambiental@yahoo.com.br, E-mail: andrecatto@terra.com.br, E-mail: katiandry@hotmail.com, E-mail: mmcforte@hotmail.com, E-mail: ruth.santana@ufrgs.br; Catto, A. L., E-mail: larissambiental@yahoo.com.br, E-mail: andrecatto@terra.com.br, E-mail: katiandry@hotmail.com, E-mail: mmcforte@hotmail.com, E-mail: ruth.santana@ufrgs.br; Rossini, K., E-mail: larissambiental@yahoo.com.br, E-mail: andrecatto@terra.com.br, E-mail: katiandry@hotmail.com, E-mail: mmcforte@hotmail.com, E-mail: ruth.santana@ufrgs.br

The production and consumption of plastics in the last decade has recorded a remarkable increase in the scientific and industrial interest in environmentally degradable polymer (EDPs). Polymers wastes are deposited improperly, such as dumps, landfills, rivers and seas, causing a serious problem by the accumulation in the environment. The abiotic processes, like the photodegradation, are the most efficient occurring in the open environmental, where the polymers undergo degradation from the action of sunlight that result from direct exposure to solar radiation, however depend of the type of chemical ageing, which is the principal component of climatic ageing. The subject ofmore » this work is to study the influence of concentration of organic pro-degradant (1, 2 and 3 % w/w) in the polypropylene (PP) exposed in natural ageing. PP samples with and without the additive were processed in plates square form, obtained by thermal compression molding (TCM) using a press at 200°C under 2 tons for 5 min, and then were exposed at natural ageing during 120 days. The presence of organic additive influenced on PP degradability, this fact was assessed by changes in the thermal and morphology properties of the samples after 120 days of natural ageing. Scanning Electronic Microscopy (SEM) results of the morphological surface of the modified PP samples showed greater degradation photochemical oxidative when compared to neat PP, due to increase of rugosity and formation of microvoids. PP samples with different pro-degradant concentration under natural ageing presented a degree of crystallinity, obtained by Differential Scanning Calorimeter (DSC) increases in comparing the neat PP.« less

Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

PubMed Central

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate. PMID:23967057

Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

PubMed

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Abiotic degradation of plastic films

NASA Astrophysics Data System (ADS)

Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

2017-01-01

Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

The degradability of biodegradable plastics in aerobic and anaerobic waste landfill model reactors.

PubMed

Ishigaki, Tomonori; Sugano, Wataru; Nakanishi, Akane; Tateda, Masafumi; Ike, Michihiko; Fujita, Masanori

2004-01-01

Degradabilities of four kinds of commercial biodegradable plastics (BPs), polyhydroxybutyrate and hydroxyvalerate (PHBV) plastic, polycaprolactone plastic (PCL), blend of starch and polyvinyl alcohol (SPVA) plastic and cellulose acetate (CA) plastic were investigated in waste landfill model reactors that were operated as anaerobically and aerobically. The application of forced aeration to the landfill reactor for supplying aerobic condition could potentially stimulate polymer-degrading microorganisms. However, the individual degradation behavior of BPs under the aerobic condition was completely different. PCL, a chemically synthesized BP, showed film breakage under the both conditions, which may have contributed to a reduction in the waste volume regardless of aerobic or anaerobic conditions. Effective degradation of PHBV plastic was observed in the aerobic condition, though insufficient degradation was observed in the anaerobic condition. But the aeration did not contribute much to accelerate the volume reduction of SPVA plastic and CA plastic. It could be said that the recalcitrant portions of the plastics such as polyvinyl alcohol in SPVA plastic and the highly substituted CA in CA plastic prevented the BP from degradation. These results indicated existence of the great variations in the degradability of BPs in aerobic and anaerobic waste landfills, and suggest that suitable technologies for managing the waste landfill must be combined with utilization of BPs in order to enhance the reduction of waste volume in landfill sites.

Pathways for degradation of plastic polymers floating in the marine environment.

PubMed

Gewert, Berit; Plassmann, Merle M; MacLeod, Matthew

2015-09-01

Each year vast amounts of plastic are produced worldwide. When released to the environment, plastics accumulate, and plastic debris in the world's oceans is of particular environmental concern. More than 60% of all floating debris in the oceans is plastic and amounts are increasing each year. Plastic polymers in the marine environment are exposed to sunlight, oxidants and physical stress, and over time they weather and degrade. The degradation processes and products must be understood to detect and evaluate potential environmental hazards. Some attention has been drawn to additives and persistent organic pollutants that sorb to the plastic surface, but so far the chemicals generated by degradation of the plastic polymers themselves have not been well studied from an environmental perspective. In this paper we review available information about the degradation pathways and chemicals that are formed by degradation of the six plastic types that are most widely used in Europe. We extrapolate that information to likely pathways and possible degradation products under environmental conditions found on the oceans' surface. The potential degradation pathways and products depend on the polymer type. UV-radiation and oxygen are the most important factors that initiate degradation of polymers with a carbon-carbon backbone, leading to chain scission. Smaller polymer fragments formed by chain scission are more susceptible to biodegradation and therefore abiotic degradation is expected to precede biodegradation. When heteroatoms are present in the main chain of a polymer, degradation proceeds by photo-oxidation, hydrolysis, and biodegradation. Degradation of plastic polymers can lead to low molecular weight polymer fragments, like monomers and oligomers, and formation of new end groups, especially carboxylic acids.

Degradation of plastic carrier bags in the marine environment.

PubMed

O'Brine, Tim; Thompson, Richard C

2010-12-01

There is considerable concern about the hazards that plastic debris presents to wildlife. Use of polymers that degrade more quickly than conventional plastics presents a possible solution to this problem. Here we investigate breakdown of two oxo-biodegradable plastics, compostable plastic and standard polyethylene in the marine environment. Tensile strength of all materials decreased during exposure, but at different rates. Compostable plastic disappeared from our test rig between 16 and 24 weeks whereas approximately 98% of the other plastics remained after 40 weeks. Some plastics require UV light to degrade. Transmittance of UV through oxo-biodegradable and standard polyethylene decreased as a consequence of fouling such that these materials received ∼ 90% less UV light after 40 weeks. Our data indicate that compostable plastics may degrade relatively quickly compared to oxo-biodegradable and conventional plastics. While degradable polymers offer waste management solutions, there are limitations to their effectiveness in reducing hazards associated with plastic debris. Copyright © 2010 Elsevier Ltd. All rights reserved.

Soil burial method for plastic degradation performed by Pseudomonas PL-01, Bacillus PL-01, and indigenous bacteria

NASA Astrophysics Data System (ADS)

Shovitri, Maya; Nafi'ah, Risyatun; Antika, Titi Rindi; Alami, Nur Hidayatul; Kuswytasari, N. D.; Zulaikha, Enny

2017-06-01

Lately, plastic bag is becoming the most important pollutant for environment since it is difficult to be naturally degraded due to it consists of long hydrocarbon polymer chains. Our previous study indicated that our pure isolate Pseudomonas PL-01 and Bacillus PL-01 could degrade about 10% plastic bag. This present study was aimed to find out whether Pseudomonas PL01 and Bacillus PL01 put a positive effect to indigenous bacteria from marginal area in doing plastic degradation with a soil burial method. Beach sand was used as a representative marginal area, and mangrove sediment was used as a comparison. Plastics were submerged into unsterile beach sand with 10% of Pseudomonas PL-01 or Bacillus PL-01 containing liquid minimal salt medium (MSM) separately, while other plastics were submerged into unsterile mangrove sediments. After 4, 8, 12 and 16 weeks, their biofilm formation on their plastic surfaces and plastic degradation were measured. Results indicated that those 2 isolates put positive influent on biofilm formation and plastic degradation for indigenous beach sand bacteria. Bacillus PL-01 put higher influent than Pseudomonas PL-01. Plastic transparent was preferable degraded than black and white plastic bag `kresek'. But anyhow, indigenous mangrove soil bacteria showed the best performance in biofilm formation and plastic degradation, even without Pseudomonas PL-01 or Bacillus PL-01 addition. Fourier Transform Infrared (FTIR) analysis complemented the results; there were attenuated peaks with decreasing peaks transmittances. This FTIR peaks indicated chemical functional group changes happened among the plastic compounds after 16 weeks incubation time.

Phyllosphere yeasts rapidly break down biodegradable plastics

PubMed Central

2011-01-01

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328

Phyllosphere yeasts rapidly break down biodegradable plastics.

PubMed

Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

2011-11-29

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands.

Nanoparticles from Degradation of Biodegradable Plastic Mulch

NASA Astrophysics Data System (ADS)

Flury, Markus; Sintim, Henry; Bary, Andy; English, Marie; Schaefer, Sean

2017-04-01

Plastic mulch films are commonly used in crop production. They provide multiple benefits, including control of weeds and insects, increase of soil and air temperature, reduction of evaporation, and prevention of soil erosion. The use of plastic mulch film in agriculture has great potential to increase food production and security. Plastic mulch films must be retrieved and disposed after usage. Biodegradable plastic mulch films, who can be tilled into the soil after usage offer great benefits as alternative to conventional polyethylene plastic. However, it has to be shown that the degradation of these mulches is complete and no micro- and nanoparticles are released during degradation. We conducted a field experiment with biodegradable mulches and tested mulch degradation. Mulch was removed from the field after the growing season and composted to facilitate degradation. We found that micro- and nanoparticles were released during degradation of the mulch films in compost. This raises concerns about degradation in soils as well.

Microbial Enzymatic Degradation of Biodegradable Plastics.

PubMed

Roohi; Bano, Kulsoom; Kuddus, Mohammed; Zaheer, Mohammed R; Zia, Qamar; Khan, Mohammed F; Ashraf, Ghulam Md; Gupta, Anamika; Aliev, Gjumrakch

2017-01-01

The renewable feedstock derived biodegradable plastics are important in various industries such as packaging, agricultural, paper coating, garbage bags and biomedical implants. The increasing water and waste pollution due to the available decomposition methods of plastic degradation have led to the emergence of biodegradable plastics and biological degradation with microbial (bacteria and fungi) extracellular enzymes. The microbes utilize biodegradable polymers as the substrate under starvation and in unavailability of microbial nutrients. Microbial enzymatic degradation is suitable from bioremediation point of view as no waste accumulation occurs. It is important to understand the microbial interaction and mechanism involved in the enzymatic degradation of biodegradable plastics under the influence of several environmental factors such as applied pH, thermo-stability, substrate molecular weight and/or complexity. To study the surface erosion of polymer film is another approach for hydrolytic degradation characteristion. The degradation of biopolymer is associated with the production of low molecular weight monomer and generation of carbon dioxide, methane and water molecule. This review reported the degradation study of various existing biodegradable plastics along with the potent degrading microbes (bacteria and fungi). Patents available on plastic biodegradation with biotechnological significance is also summarized in this paper. This paper assesses that new disposal technique should be adopted for the degradation of polymers and further research is required for the economical production of biodegradable plastics along with their enzymatic degradation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Dumped Munitions in the Baltic Sea - Evaluation of the Problem

NASA Astrophysics Data System (ADS)

Beldowski, J.; Jakacki, J.; Vanninen, P.; Lang, T.

2016-12-01

Dumped Chemical Weapons pose an actual environmental and security hazard in the Baltic Sea Region. Their actual position is unknown, and pollution originating from corroded munitions is only roughly estimated. Several research projects were devoted to evaluate the magnitude of the problem. During three international projects, roughly 2000 km2 were surveyed, and more than 200 ROV missions were performed to investigate found objects. . Results suggest that munitions containing CWAs are more scattered on the seafloor than suspected, and previously undocumented dumpsite was discovered in Gdansk Deep. Chemical Warfare Agents (CWA) degradation products were found in the sediments in immediate vicinity of the objects, and sediment pollution was observed even at 40m distance. Analysis of CWA degradation products in the sediments showed widespread contamination in Bornholm Deep area, and more variable pattern of local hotspots in the Gotland and Gdansk Deeps. The latter seem to contain several contaminated areas, which identifies it rather as an unofficial dumping ground than only containing munitions originating from en-route dumping. Bottom currents observed in the dumpsites were strong enough for sediment re-suspension, and contributed to the transport of polluted sediments. Spreading of CWA was modelled using POP3 hydrodynamic model augmented with sediment erosion and benthic boundary layer modules. It follows from the models, that depending on wind conditions, resuspended contaminated sediemnts may remain in the water column for several days up to few weeks, and be transported over the distances up to 15 km. Biomarkers of environmental stress were measured in fish from the dumpsites and caged mussels, and indicated environmental stress in organisms from dumpsites as compared to control. Toxicity of found CWA degradation products was examined in laboratory studies. . Nonetheless, both species showed significantly elevated molecular and cellular level responses at contaminated sites compared to reference sites. It follows from the studies, that pollution originating from dumped munitions is local, and below acute toxicity levels. However chronic toxicity and adverse impact on the ecosystem may not be excluded, pollution may also spread to adjacent areas as the corrosion of the objects progresses.

Assessment of floating plastic debris in surface water along the Seine River.

PubMed

Gasperi, Johnny; Dris, Rachid; Bonin, Tiffany; Rocher, Vincent; Tassin, Bruno

2014-12-01

This study is intended to examine the quality and quantity of floating plastic debris in the River Seine through use of an extensive regional network of floating debris-retention booms; it is one of the first attempts to provide reliable information on such debris at a large regional scale. Plastic debris represented between 0.8% and 5.1% of total debris collected by weight. A significant proportion consisted of food wrappers/containers and plastic cutlery, probably originating from voluntary or involuntary dumping, urban discharges and surface runoff. Most plastic items are made of polypropylene, polyethylene and, to a lesser extent, polyethylene terephthalate. By extrapolation, some 27 tons of floating plastic debris are intercepted annually by this network; corresponding to 2.3 g per Parisian inhabitant per year. Such data could serve to provide a first evaluation of floating plastic inputs conveyed by rivers. Copyright © 2014 Elsevier Ltd. All rights reserved.

Neutral beam dump with cathodic arc titanium gettering

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

Smirnov, A.; Korepanov, S. A.; Putvinski, S.

An incomplete neutral beam capture can degrade the plasma performance in neutral beam driven plasma machines. The beam dumps mitigating the shine-through beam recycling must entrap and retain large particle loads while maintaining the beam-exposed surfaces clean of the residual impurities. The cathodic arc gettering, which provides high evaporation rate coupled with a fast time response, is a powerful and versatile technique for depositing clean getter films in vacuum. A compact neutral beam dump utilizing the titanium arc gettering was developed for a field-reversed configuration plasma sustained by 1 MW, 20-40 keV neutral hydrogen beams. The titanium evaporator features amore » new improved design. The beam dump is capable of handling large pulsed gas loads, has a high sorption capacity, and is robust and reliable. With the beam particle flux density of 5 x 10{sup 17} H/(cm{sup 2}s) sustained for 3-10 ms, the beam recycling coefficient, defined as twice the ratio of the hydrogen molecular flux leaving the beam dump to the incident flux of high-energy neutral atoms, is {approx}0.7. The use of the beam dump allows us to significantly reduce the recycling of the shine-through neutral beam as well as to improve the vacuum conditions in the machine.« less

Effects of lead pollution at industrial contaminated sites on sentinel juvenile Achatina achatina.

PubMed

Ebenso, I E; Ologhobo, A D

2009-01-01

We investigated juvenile Achatina achatina snails exposed as sentinels in plastic cages for 12 weeks to compare lead pollution at dump sites of abandoned battery factory (Niger Delta, Nigeria). Results indicated 0.56, 20.37, 200.42 and 1200.30 microg/g soil lead at control, storage, dried effluent and waste dump sites, respectively. There were significant (p < 0.05) depression in snail growth with increasing level of lead pollution. Snails were tolerant of all levels of lead pollution with no mortalities. This novel approach provides a basis for use of snail data in environmental pollution assessment of industrial sites.

Industrial innovations for tomorrow: Advances in industrial energy-efficiency technologies. Degradable plastic made from potato peels

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

Not Available

Stimulated by public demand and state and federal legislation, industry has begun to develop bio- and photo- degradable plastics. so far, however, none of these degradable plastics meets all of the criteria for success - adequate physical and mechanical properties for the desired use, cost-effectiveness, and 100% degradability. Polylactic acid (PLA) plastic is one degradable plastic that shows promise. It has the desired properties and is 100% degradable. However, PLA plastic made by conventional techniques is not cost effective. Made from lactic acid, which is typically made form petroleum using a very costly synthesis process. Lactic acid can also bemore » made from carbohydrates (starches), found in food processing wastes such as potato wastes, cheese whey, and sorghum. Conversion of starch to simple sugars, and fermentation of these sugars can produce lactic acid.« less

Observation of the degradation of three types of plastic pellets exposed to UV irradiation in three different environments.

PubMed

Cai, Liqi; Wang, Jundong; Peng, Jinping; Wu, Ziqing; Tan, Xiangling

2018-07-01

Plastic debris represents one of the most prevalent and persistent pollution problems in the marine environment. In particular, microplastics that are mainly degraded from larger plastic debris have become a growing environmental concern. However, studies on the degradation of plastics in the aquatic environment that hydrobios reside in have been limited, while several studies regarding the degradation of plastics have been conducted under outdoor or accelerated weathering conditions. Thus, observation of the degradation of three types of virgin plastic pellets exposed to UV irradiation in three different environments (i.e., simulated seawater, ultrapure water, and a waterless (air) condition) was carried out. Data on the changes in physical and chemical properties were collected. The FTIR spectra showed that hydroxyl groups and carbonyl groups developed in three types of weathered plastic pellets under the air and ultrapure water environmental conditions after 3months of UV irradiation, while only carbonyl groups were found in plastic pellets in the simulated seawater environment. In contrast, the Raman spectra showed no significant changes in the weathered plastic pellets, but there were different intensities of characteristic peaks after exposure to UV irradiation. In addition, SEM images illustrated that granular oxidation, cracks and flakes were common patterns during degradation, and the plastic pellets in the three different environments experienced different levels of chemical weathering. We suggest that further studies on the degradation processes of plastic debris are needed to predict the fate of plastic debris in the environment. Copyright © 2018 Elsevier B.V. All rights reserved.

Hydrogeology, water quality, and potential for transport of organochlorine pesticides in ground water at the North Hollywood Dump, Memphis, Tennessee

USGS Publications Warehouse

Broshears, R.E.; Bradley, M.W.

1992-01-01

Geologic, hydrologic, and water-quality data indicate that ground-water contamination is confined to shallow horizons within the unconfined aquifer underlying the North Hollywood Dump in Memphis, Tennessee. The dump is a closed municipal-industrial landfill that has been ranked as Tennessee's potentially most dangerous hazardous-waste site. Toxic constituents of concern at the dump include residues from the manufacture of organochlorine pesticides. The dump overlies an unconfined aquifer of unconsolidated sands, silts, and clays. During average hydrologic conditions, ground waterflows beneath the dump at a mean velocity of approximately 3 feet per day and discharges to the Wolf River. Leachate from the dump mixes with underlying ground water, resulting in increased concentrations of dissolved solids and organic carbon downgradient from the dump. The mobility of chlordane, a representative organochlorine pesticide, is limited by its low solubility and its strong affinity for sand, silt, and clays of the aquifer. Degradation of chlordane may occur slowly, if at all, in the aquifer. Based on estimates of mean ground-water velocity and retardation of the pesticide due to sorption, mean travel times for chlordane migrating from the dump to the ground-water discharge zone are of the order of 50 to 500 years. Simulations of chlordane concentration resulting from the discharge of contaminated ground water and complete mixing in the Wolf River are sensitive to assumptions about chlordane persistence in the unconfined aquifer. If the half life of chlordane in the aquifer is assumed to be 30 years or less, the simulated concentration of chlordane in the Wolf River under average flow conditions is less than the most stringent water-quality criterion.

Current research trends on plastic pollution and ecological impacts on the soil ecosystem: A review.

PubMed

Chae, Yooeun; An, Youn-Joo

2018-05-09

Plastic pollution in the environment is currently receiving worldwide attention. Improper dumping of disused or abandoned plastic wastes leads to contamination of the environment. In particular, the disposal of municipal wastewater effluent, sewage sludge landfill, and plastic mulch from agricultural activities is a serious issue and of major concern regarding soil pollution. Compared to plastic pollution in the marine and freshwater ecosystems, that in the soil ecosystem has been relatively neglected. In this study, we discussed plastic pollution in the soil environment and investigated research on the effects of plastic wastes, especially microplastics, on the soil ecosystem. We found that earthworms have been predominantly used as the test species in investigating the effects of soil plastic pollution on organisms. Therefore, further research investigating the effects of plastic on other species models (invertebrates, plants, microorganisms, and insects) are required to understand the effects of plastic pollution on the overall soil ecosystem. In addition, we suggest other perspectives for future studies on plastic pollution and soil ecotoxicity of plastics wastes, providing a direction for such research. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biofilm and Diatom Succession on Polyethylene (PE) and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

PubMed Central

Laforsch, Christian; Weber, Miriam

2015-01-01

The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth) and a pelagic habitat (3 m water depth) to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM) analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation and composition are affected by the plastic type and habitat. Further, it reveals that already within two weeks biodegradable plastic shows signs of degradation in the benthic and pelagic habitat. PMID:26394047

Biofilm and Diatom Succession on Polyethylene (PE) and Biodegradable Plastic Bags in Two Marine Habitats: Early Signs of Degradation in the Pelagic and Benthic Zone?

PubMed

Eich, Andreas; Mildenberger, Tobias; Laforsch, Christian; Weber, Miriam

2015-01-01

The production of biodegradable plastic is increasing. Given the augmented littering of these products an increasing input into the sea is expected. Previous laboratory experiments have shown that degradation of plastic starts within days to weeks. Little is known about the early composition and activity of biofilms found on biodegradable and conventional plastic debris and its correlation to degradation in the marine environment. In this study we investigated the early formation of biofilms on plastic shopper bags and its consequences for the degradation of plastic. Samples of polyethylene and biodegradable plastic were tested in the Mediterranean Sea for 15 and 33 days. The samples were distributed equally to a shallow benthic (sedimentary seafloor at 6 m water depth) and a pelagic habitat (3 m water depth) to compare the impact of these different environments on fouling and degradation. The amount of biofilm increased on both plastic types and in both habitats. The diatom abundance and diversity differed significantly between the habitats and the plastic types. Diatoms were more abundant on samples from the pelagic zone. We anticipate that specific surface properties of the polymer types induced different biofilm communities on both plastic types. Additionally, different environmental conditions between the benthic and pelagic experimental site such as light intensity and shear forces may have influenced unequal colonisation between these habitats. The oxygen production rate was negative for all samples, indicating that the initial biofilm on marine plastic litter consumes oxygen, regardless of the plastic type or if exposed in the pelagic or the benthic zone. Mechanical tests did not reveal degradation within one month of exposure. However, scanning electron microscopy (SEM) analysis displayed potential signs of degradation on the plastic surface, which differed between both plastic types. This study indicates that the early biofilm formation and composition are affected by the plastic type and habitat. Further, it reveals that already within two weeks biodegradable plastic shows signs of degradation in the benthic and pelagic habitat.

Isolation and characterization of a bacterium that degrades various polyester-based biodegradable plastics.

PubMed

Teeraphatpornchai, T; Nakajima-Kambe, T; Shigeno-Akutsu, Y; Nakayama, M; Nomura, N; Nakahara, T; Uchiyama, H

2003-01-01

Microorganisms isolated from soil samples were screened for their ability to degrade various biodegradable polyester-based plastics. The most active strain, designated as strain TB-13, was selected as the best strain for degrading these plastics. From its phenotypic and genetic characteristics, strain TB-13 was closely related to Paenibacillus amyloyticus. It could degrade poly(lactic acid), poly(butylene succinate), poly(butylene succinate-co-adipate), poly(caprolactone) and poly(ethylene succinate) but not poly(hydroxybutylate-co-valerate). However, it could not utilize these plastics as sole carbon sources. Both protease and esterase activities, which may be involved in the degradation of plastic, were constitutively detected in the culture broth.

Selection and screening of microbial consortia for efficient and ecofriendly degradation of plastic garbage collected from urban and rural areas of Bangalore, India.

PubMed

Skariyachan, Sinosh; Megha, M; Kini, Meghna Niranjan; Mukund, Kamath Manali; Rizvi, Alya; Vasist, Kiran

2015-01-01

Industrialization and urbanization have led to massive accumulation of plastic garbage all over India. The persistence of plastic in soil and aquatic environment has become ecological threat to the metropolitan city such as Bangalore, India. Present study investigates an ecofriendly, efficient and cost-effective approach for plastic waste management by the screening of novel microbial consortia which are capable of degrading plastic polymers. Plastic-contaminated soil and water samples were collected from six hot spots of urban and rural areas of Bangalore. The plastic-degrading bacteria were enriched, and degradation ability was determined by zone of clearance method. The percentage of polymer degradation was initially monitored by weight loss method, and the main isolates were characterized by standard microbiology protocols. These isolates were used to form microbial consortia, and the degradation efficiency of the consortia was compared with individual isolate and known strains obtained from the Microbial Type Culture Collection (MTCC) and Gene Bank, India. One of the main enzymes responsible for polymer degradation was identified, and the biodegradation mechanism was hypothesized by bioinformatics studies. From this study, it is evident that the bacteria utilized the plastic polymer as a sole source of carbon and showed 20-50% weight reduction over a period of 120 days. The two main bacteria responsible for the degradation were microbiologically characterized to be Pseudomonas spp. These bacteria could grow optimally at 37 °C in pH 9.0 and showed 35-40% of plastic weight reduction over 120 days. These isolates were showed better degradation ability than known strains from MTCC. The current study further revealed that the microbial consortia formulated by combining Psuedomonas spp. showed 40 plastic weight reduction over a period of 90 days. Further, extracellular lipase, one of the main enzymes responsible for polymer degradation, was identified. The computational docking studies suggested that polyethylene glycol and polystyrene present in the plastics might have good interaction towards the microbial lipase with stable binding and interacting forces which probably could be one of the reasons for the degradative mechanisms.

Thermal degradation and plasticizing mechanism of poly(vinyl chloride) plasticized with a novel cardanol derived plasticizer

NASA Astrophysics Data System (ADS)

Chen, J.; Nie, X. A.; Jiang, J. C.; Zhou, Y. H.

2018-01-01

A natural plasticizer cardanol derivatives glycidyl ether (CGE) was synthesized and employed as a plasticizer for the poly(vinyl chloride). The effect of CGE on thermal degradation of PVC films and its plasticizing mechanism were firstly reported. The molecular structure of CGE was characterized with Fourier transform infrared spectroscopy (FTIR). Thermal properties, degradation properties and compatibility of the PVC films were investigated by Differential scanning calorimeter analysis (DSC), Thermogravimetric analysis (TGA) and FTIR, respectively. Compared with the commercial plasticizers dioctylphthalate (DOP), CGE can endow PVC film with a decrease of 4.31 °C in glass transition temperature (Tg), an increase of 24.01 °C and 25.53 °C in 10% weight loss (T 10) and 50% weight loss (T 50) respectively, and a higher activetion energy of thermal degradation (Ea ).

Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

PubMed

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

2014-01-01

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.

77 FR 11401 - Marine Sanitation Devices (MSDs): No Discharge Zone (NDZ) for California State Marine Waters

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-27

... Plastic Pollution Research and Control Act of 1987, and the Ocean Dumping Act, address pollution within... related legislation in 2003-2005 to limit pollution from large passenger and large oceangoing vessels. In...; (3) to further regulate landside sources of pollution; (4) to improve inspection and testing...

Biodegradability of Plastics: Challenges and Misconceptions.

PubMed

Kubowicz, Stephan; Booth, Andy M

2017-11-07

Plastics are one of the most widely used materials and, in most cases, they are designed to have long life times. Thus, plastics contain a complex blend of stabilizers that prevent them from degrading too quickly. Unfortunately, many of the most advantageous properties of plastics such as their chemical, physical and biological inertness and durability present challenges when plastic is released into the environment. Common plastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) are extremely persistent in the environment, where they undergo very slow fragmentation (projected to take centuries) into small particles through photo-, physical, and biological degradation processes 1 . The fragmentation of the material into increasingly smaller pieces is an unavoidable stage of the degradation process. Ultimately, plastic materials degrade to micron-sized particles (microplastics), which are persistent in the environment and present a potential source of harm for organisms.

Study of microbes having potentiality for biodegradation of plastics.

PubMed

Ghosh, Swapan Kumar; Pal, Sujoy; Ray, Sumanta

2013-07-01

Plastic is a broad name given to the different types of organic polymers having high molecular weight and is commonly derived from different petrochemicals. Plastics are generally not biodegradable or few are degradable but in a very slow rate. Day by day, the global demand of these polymers is sharply increasing; however, considering their abundance and potentiality in causing different environmental hazards, there is a great concern in the possible methods of degradation of plastics. Recently, there have been some debates at the world stage about the potential degradation procedures of these synthetic polymers and microbial degradation has emerged as one of the potential alternative ways of degradation of plastics. Alternatively, some scientists have also reported many adverse effects of these polymers in human health, and thus, there is an immediate need of a potential screening of some potential microbes to degrade these synthetic polymers. In this review, we have taken an attempt to accumulate all information regarding the chemical nature along with some potential microbes and their enzymatic nature of biodegradation of plastics along with some key factors that affect their biodegradability.

Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

PubMed Central

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

2014-01-01

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process. PMID:25419675

Biological degradation of plastics: a comprehensive review.

PubMed

Shah, Aamer Ali; Hasan, Fariha; Hameed, Abdul; Ahmed, Safia

2008-01-01

Lack of degradability and the closing of landfill sites as well as growing water and land pollution problems have led to concern about plastics. With the excessive use of plastics and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. Awareness of the waste problem and its impact on the environment has awakened new interest in the area of degradable polymers. The interest in environmental issues is growing and there are increasing demands to develop material which do not burden the environment significantly. Biodegradation is necessary for water-soluble or water-immiscible polymers because they eventually enter streams which can neither be recycled nor incinerated. It is important to consider the microbial degradation of natural and synthetic polymers in order to understand what is necessary for biodegradation and the mechanisms involved. This requires understanding of the interactions between materials and microorganisms and the biochemical changes involved. Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. This paper reviews the current research on the biodegradation of biodegradable and also the conventional synthetic plastics and also use of various techniques for the analysis of degradation in vitro.

Combined Chemical Activation and Fenton Degradation to Convert Waste Polyethylene into High-Value Fine Chemicals.

PubMed

Chow, Cheuk-Fai; Wong, Wing-Leung; Ho, Keith Yat-Fung; Chan, Chung-Sum; Gong, Cheng-Bin

2016-07-04

Plastic waste is a valuable organic resource. However, proper technologies to recover usable materials from plastic are still very rare. Although the conversion/cracking/degradation of certain plastics into chemicals has drawn much attention, effective and selective cracking of the major waste plastic polyethylene is extremely difficult, with degradation of C-C/C-H bonds identified as the bottleneck. Pyrolysis, for example, is a nonselective degradation method used to crack plastics, but it requires a very high energy input. To solve the current plastic pollution crisis, more effective technologies are needed for converting plastic waste into useful substances that can be fed into the energy cycle or used to produce fine chemicals for industry. In this study, we demonstrate a new and effective chemical approach by using the Fenton reaction to convert polyethylene plastic waste into carboxylic acids under ambient conditions. Understanding the fundamentals of this new chemical process provides a possible protocol to solve global plastic-waste problems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biodegradation of plastics.

PubMed

Shimao, M

2001-06-01

Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. Recent work has included studies of the distribution of synthetic polymer-degrading microorganisms in the environment, the isolation of new microorganisms for biodegradation, the discovery of new degradation enzymes, and the cloning of genes for synthetic polymer-degrading enzymes.

Anthropogenic Pollutants in Extracts from Maritsa Iztok Dumps

NASA Astrophysics Data System (ADS)

Stefanova, Maya; Milakovska, Zlatka; Marinov, Stefan

2017-12-01

Coals are suspected for many human health problems and are an object of the new discipline - “medical geology”. Potential human health risk of organic compounds with coal/lignite provenance includes endocrine disruption, nephrotoxicity, cancer, etc. Recent investigations proved that different organic components, i.e. hydrocarbons, phenols etc. move through/release out of the dump area as a result of alteration processes of the organic matter (OM) caused by the wash-out and/or drainage processes. The timeliness of the present study is based on the scarcity of information on organic geochemistry of dump materials from open pit coal mines and weathered lignites in particular. The limited number of studies on dumps clarifies that even for the “short” time span (some tens of years) in geological point of view, processes of transformation of the extractable OM are detectable. The secondary phases, a result of the OM transformations, move through and out of the dump area and could be potential contaminants for the surface/underground waters and soils in the area. Another environmental problem comes from the air-born VOCs and products of the modern chemical industry. By GC-MS in the slightly polar fractions of the chloroform extracts of dump samples a broad set of components was determined, i.e. phthalates (dominant), i-propyl palmitate, i-propyl myristate, n-hexyl benzoates, etc. These organic contaminants could be regarded more likely as anthropogenic (originating from plasticizers, industrial pollutants, etc.). Presently, it seems that the identified compounds do not represent an acute toxic risk from an environmental viewpoint. However, some compounds could raise concerns and further attention is needed to be focused on them.

Degradation of Degradable Starch-Polyethylene Plastics in a Compost Environment †

PubMed Central

Johnson, Kenneth E.; Pometto, Anthony L.; Nikolov, Zivko L.

1993-01-01

The degradation performance of 11 types of commercially produced degradable starch-polyethylene plastic compost bags was evaluated in municipal yard waste compost sites at Iowa State University (Ames) and in Carroll, Dubuque, and Grinnell, Iowa. Masterbatches for plastic production were provided by Archer Daniels Midland Co. (Decatur, Ill.), St. Lawrence Starch Co. Ltd. (Mississauga, Ontario, Canada), and Fully Compounded Plastics (Decatur, Ill.). Bags differed in starch content (5 to 9%) and prooxidant additives (transition metals and a type of unsaturated vegetable oil). Chemical and photodegradation properties of each material were evaluated. Materials from St. Lawrence Starch Co. Ltd. and Fully Compounded Plastics photodegraded faster than did materials from Archer Daniels Midland Co., whereas all materials containing transition metals demonstrated rapid thermal oxidative degradation in 70°C-oven (dry) and high-temperature, high-humidity (steam chamber) treatments. Each compost site was seeded with test strips (200 to 800 of each type) taped together, which were recovered periodically over an 8- to 12-month period. At each sampling date, the compost row temperature was measured (65 to 95°C), the location of the recovered test strip was recorded (interior or exterior), and at least four strips were recovered for evaluation. Degradation was followed by measuring the change in polyethylene molecular weight distribution via high-temperature gel permeation chromatography. Our initial 8-month study indicated that materials recovered from the interior of the compost row demonstrated very little degradation, whereas materials recovered from the exterior degraded well. In the second-year study, however, degradation was observed in several plastic materials recovered from the interior of the compost row by month 5 at the Carroll site and almost every material by month 12 at the Grinnell site. The plastic bags collected from each community followed a similar degradation pattern. To our knowledge, this is the first scientific study demonstrating significant polyethylene degradation by these materials in a compost environment. PMID:16348914

Degradation of degradable starch-polyethylene plastics in a compost environment.

PubMed

Johnson, K E; Pometto, A L; Nikolov, Z L

1993-04-01

The degradation performance of 11 types of commercially produced degradable starch-polyethylene plastic compost bags was evaluated in municipal yard waste compost sites at Iowa State University (Ames) and in Carroll, Dubuque, and Grinnell, Iowa. Masterbatches for plastic production were provided by Archer Daniels Midland Co. (Decatur, Ill.), St. Lawrence Starch Co. Ltd. (Mississauga, Ontario, Canada), and Fully Compounded Plastics (Decatur, Ill.). Bags differed in starch content (5 to 9%) and prooxidant additives (transition metals and a type of unsaturated vegetable oil). Chemical and photodegradation properties of each material were evaluated. Materials from St. Lawrence Starch Co. Ltd. and Fully Compounded Plastics photodegraded faster than did materials from Archer Daniels Midland Co., whereas all materials containing transition metals demonstrated rapid thermal oxidative degradation in 70 degrees C-oven (dry) and high-temperature, high-humidity (steam chamber) treatments. Each compost site was seeded with test strips (200 to 800 of each type) taped together, which were recovered periodically over an 8- to 12-month period. At each sampling date, the compost row temperature was measured (65 to 95 degrees C), the location of the recovered test strip was recorded (interior or exterior), and at least four strips were recovered for evaluation. Degradation was followed by measuring the change in polyethylene molecular weight distribution via high-temperature gel permeation chromatography. Our initial 8-month study indicated that materials recovered from the interior of the compost row demonstrated very little degradation, whereas materials recovered from the exterior degraded well. In the second-year study, however, degradation was observed in several plastic materials recovered from the interior of the compost row by month 5 at the Carroll site and almost every material by month 12 at the Grinnell site. The plastic bags collected from each community followed a similar degradation pattern. To our knowledge, this is the first scientific study demonstrating significant polyethylene degradation by these materials in a compost environment.

Characterization and evaluation physical properties biodegradable plastic composite from seaweed (Eucheuma cottonii)

NASA Astrophysics Data System (ADS)

Deni, Glar Donia; Dhaningtyas, Shalihat Afifah; Fajar, Ibnu; Sudarno

2015-12-01

The characterization and evaluation of biodegradable plastic composed of a mixture PVA - carrageenan - chitosan was conducted in this study. Obtained data were then compared to commercial biodegradable plastic. Characteristic of plastic was mechanical tested such as tensile - strength and elongation. Plastic degradation was studied using composting method for 7 days and 14 days. The results showed that the increase carrageenan will decrease tensile-strength and elongation plastic composite. In addition, increase carrageenan would increase the degraded plastics composite.

Degradation and metabolism of synthetic plastics and associated products by Pseudomonas sp.: capabilities and challenges.

PubMed

Wilkes, R A; Aristilde, L

2017-09-01

Synthetic plastics, which are widely present in materials of everyday use, are ubiquitous and slowly-degrading polymers in environmental wastes. Of special interest are the capabilities of microorganisms to accelerate their degradation. Members of the metabolically diverse genus Pseudomonas are of particular interest due to their capabilities to degrade and metabolize synthetic plastics. Pseudomonas species isolated from environmental matrices have been identified to degrade polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polyethylene terephthalate, polyethylene succinate, polyethylene glycol and polyvinyl alcohol at varying degrees of efficiency. Here, we present a review of the current knowledge on the factors that control the ability of Pseudomonas sp. to process these different plastic polymers and their by-products. These factors include cell surface attachment within biofilms, catalytic enzymes involved in oxidation or hydrolysis of the plastic polymer, metabolic pathways responsible for uptake and assimilation of plastic fragments and chemical factors that are advantageous or inhibitory to the biodegradation process. We also highlight future research directions required in order to harness fully the capabilities of Pseudomonas sp. in bioremediation strategies towards eliminating plastic wastes. © 2017 The Society for Applied Microbiology.

Biodegradation of compostable and oxodegradable plastic films by backyard composting and bioaugmentation.

PubMed

Quecholac-Piña, Xochitl; García-Rivera, Mariel Anel; Espinosa-Valdemar, Rosa María; Vázquez-Morillas, Alethia; Beltrán-Villavicencio, Margarita; Cisneros-Ramos, Adriana de la Luz

2017-11-01

Plastics are widely used in the production of short-life products, which are discarded producing an accumulation of these materials and problems due to their persistence in the environment and waste management systems. Degradable plastics (compostable, oxodegradable) have been presented as an alternative to decrease the negative effect of plastic waste. In this research, the feasibility of degrading a commercially available compostable film and oxodegradable polyethylene, with and without previous abiotic oxidation, is assessed in a home composting system. Reactors (200 L) were used to degrade the plastic films along with a mixture of organic food waste (50 %), mulch (25 %), and dry leaves (25 %), amended with yeast and a solution of brown sugar to increase the speed of the process. The presence of the plastic film did not affect the composting process, which showed an initial increase in temperature and typical profiles for moisture content, pH, with a final C/N of 17.4. After 57 days, the compostable plastic has decreased its mechanical properties in more than 90 %, while the oxodegradable film did not show significant degradation if it was not previously degraded by UV radiation. The use of these plastics should be assessed against the prevailing waste management system in each city or country. In the case of Mexico, which lacks the infrastructure for industrial composting, home composting could be an option to degrade compostable plastics along organic waste. However, more testing is needed in order to set the optimal parameters of the process.

WEATHERABILITY OF ENHANCED DEGRADABLE PLASTICS

EPA Science Inventory

The main objective of this study was to assess the performance and the asociated variability of several selected enhanced degradable plastic materials under a variety of different exposure conditions. Other objectives were to identify the major products formed during degradation ...

Plastics to fuel: A review

USDA-ARS?s Scientific Manuscript database

This paper reviews recent developments in catalytic and non-catalytic degradation of waste plastics into fuels. Thermal degradation decomposes plastic into three fractions: gas, crude oil, and solid residue. Crude oil from non-catalytic pyrolysis is usually composed of higher boiling point hydrocarb...

Prospects for microbiological solutions to environmental pollution with plastics.

PubMed

Krueger, Martin C; Harms, Hauke; Schlosser, Dietmar

2015-11-01

Synthetic polymers, commonly named plastics, are among the most widespread anthropogenic pollutants of marine, limnic and terrestrial ecosystems. Disruptive effects of plastics are known to threaten wildlife and exert effects on natural food webs, but signs for and knowledge on plastic biodegradation are limited. Microorganisms are the most promising candidates for an eventual bioremediation of environmental plastics. Laboratory studies have reported various effects of microorganisms on many types of polymers, usually by enzymatic hydrolysis or oxidation. However, most common plastics have proved to be highly recalcitrant even under conditions known to favour microbial degradation. Knowledge on environmental degradation is yet scarcer. With this review, we provide a comprehensive overview of the current knowledge on microbiological degradation of several of the most common plastic types. Furthermore, we illustrate the analytical challenges concerning the evaluation of plastic biodegradation as well as constraints likely standing against the evolution of effective biodegradation pathways.

Characterization of bacterial isolates from rubber dump site and their use in biodegradation of isoprene in batch and continuous bioreactors.

PubMed

Srivastva, Navnita; Shukla, Awadhesh Kumar; Singh, Ram Sharan; Upadhyay, Siddh Nath; Dubey, Suresh Kumar

2015-01-01

Bacterial isolates from contaminated soil of a waste rubber dumping site were isolated and characterized using biochemical and molecular approaches. Isoprene degradation kinetics in batch mode (isoprene concentration: 100-1000 ppm) revealed the degradation efficiency of isolates as: Pseudomonas sp. (83%)>Alcaligenes sp. (70%)>Klebsiella sp. (68.5%). The most efficient isolate Pseudomonas sp. was finally inoculated in a specifically designed bioreactor system comprising a bioscrubber and a biofilter packed with polyurethane foam connected in series. The bioscrubber and biofilter units when operated in a series showed more than 90% removal efficiency up to the inlet loading rate (IL) of 371.1g/m(3)/h. Maximum elimination capacity (EC) of biofilter was found to be an order of magnitude greater than that for bioscrubber. Oxidative cleavage of the double bond of isoprene has been revealed through IR spectra of the leachate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Marine pollution originating from purse seine and longline fishing vessel operations in the Western and Central Pacific Ocean, 2003-2015.

PubMed

Richardson, Kelsey; Haynes, David; Talouli, Anthony; Donoghue, Michael

2017-03-01

Fisheries observer data recorded between 2003 and 2015 on-board purse seine and longline vessels operating in the Western and Central Pacific Ocean reported more than 10 000 pollution incidents within the exclusive economic zones (EEZs) of 25 Pacific countries and territories, and in international waters. A majority of the reported purse seine pollution incidents related to dumping of plastics waste. Other common pollution incidents related to oil spillages and to abandoned, lost or dumped fishing gear. Data analysis highlighted the need for increased monitoring, reporting, and enforcement of pollution violations by all types of fishing vessels operating in the Pacific region; a regional outreach and compliance assistance programme on marine pollution prevention and improvements in Pacific port waste reception facilities.

Potential of bacteria isolated from landfill soil in degrading low density polyethylene plastic

NASA Astrophysics Data System (ADS)

Munir, E.; Sipayung, F. C.; Priyani, N.; Suryanto, D.

2018-03-01

Plastic is an important material and used for many purposes. It is returned to the environment as a waste which is recently considered as the second largest solid waste. The persistency of plastic in the environment has been attracted researchers from a different point of view. The study of the degradation of plastic using bacteria isolated from local landfill soil was conducted. Low density polyethylene (LDPE) plastic was used as tested material. Potential isolates were obtained by culturing the candidates in mineral salt medium broth containing LDPE powder. Two of ten exhibited better growth response in the selection media and were used in degradation study. Results showed that isolate SP2 and SP4 reduced the weight of LDPE film significantly to a weight loss of 10.16% and 12.06%, respectively after four weeks of incubation. Scanning electron micrograph analyses showed the surface of LDPE changed compared to the untreated film. It looked rough and cracked, and bacteria cells attached to the surface was also noticed. Fourier transform infrared spectroscopy analyses confirmed the degradation of LDPE film. These results indicated that bacteria isolated from landfill might play an important role in degrading plastic material in the landfill.

Polyethylene bio-degradation by caterpillars of the wax moth Galleria mellonella.

PubMed

Bombelli, Paolo; Howe, Christopher J; Bertocchini, Federica

2017-04-24

Plastics are synthetic polymers derived from fossil oil and largely resistant to biodegradation. Polyethylene (PE) and polypropylene (PP) represent ∼92% of total plastic production. PE is largely utilized in packaging, representing ∼40% of total demand for plastic products (www.plasticseurope.org) with over a trillion plastic bags used every year [1]. Plastic production has increased exponentially in the past 50 years (Figure S1A in Supplemental Information, published with this article online). In the 27 EU countries plus Norway and Switzerland up to 38% of plastic is discarded in landfills, with the rest utilized for recycling (26%) and energy recovery (36%) via combustion (www.plasticseurope.org), carrying a heavy environmental impact. Therefore, new solutions for plastic degradation are urgently needed. We report the fast bio-degradation of PE by larvae of the wax moth Galleria mellonella, producing ethylene glycol. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Politics of Environmental Destruction and the Use of Nature as Teacher and Site of Learning.

ERIC Educational Resources Information Center

Lengwati, Makkies David

1995-01-01

Lack of education, low environmental awareness, and environmental racism (for example, siting toxic waste dumps in certain communities) contribute to the degradation of the environment in South Africa. Educational initiatives include learning from nature and fostering political action. (SK)

40 CFR 229.2 - Transport of target vessels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Transport of target vessels. 229.2 Section 229.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING GENERAL... may degrade the marine environment, -including without limitation (i) emptying of all fuel tanks and...

40 CFR 229.2 - Transport of target vessels.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Transport of target vessels. 229.2 Section 229.2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING GENERAL... may degrade the marine environment, -including without limitation (i) emptying of all fuel tanks and...

Waste Management in Greater Dhaka City.

ERIC Educational Resources Information Center

Rahman, M. H.

1993-01-01

This study focuses on the environmental degradation of Greater Dhaka City (GDC) resulting from pollution created by the indiscriminate disposal of industrial wastes, open dumping of solid wastes, inadequate treatment and disposal of domestic sewage, and unplanned disposal of leachate from agricultural land. Measures to protect the GDC environment…

Relating plastic in the ocean to ecological harm, a review of recent progress in risk analysis

NASA Astrophysics Data System (ADS)

Schuyler, Q. A.; Hardesty, B. D.; Wilcox, C.; van Sebille, E.; Mallos, N. J.; Leonard, G. H.

2016-02-01

Plastic pollution in the ocean is emerging as a global environmental concern. Estimates suggest that we dump on the order of 8.4 million tons of plastic in the ocean each year. This plastic reaches substantial concentrations, with at sea sampling measuring densities over 580,000 items per square kilometer. However, it is difficult to relate this exposure to resulting ecological impacts. Animals dying due to plastic ingestion or entanglement may not was ahsore, and sampling at sea is expensive and infrequent. Thus demonstrating a direct relationship between plastic in the envioronment and harm to marine wildlife is challenging. Here we review current progress on risk assessment for impacts to marine wildlife from plastic pollution. The analyses we review range from expert elicitation to integrated statistical and physical models. They range widely in scope, from estimates at the individual level to who taxa analysis. Some of the analyses reach only to exposure to the pressure, whie others carry through to estimate demographic impacts and even mortality due to ingestion of or entanglement in plastic debris in the ocean. We summarize the results of these studies, and provide a roadmap for future contributions toward estimating the actual ecological impact of plastic pollution.

40 CFR 238.10 - Purpose and applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

... DEGRADABLE PLASTIC RING CARRIERS General Provisions § 238.10 Purpose and applicability. The purpose of this part is to require that plastic ring carriers be made of degradable materials as described in §§ 238.20 and 238.30. The requirements of this part apply to all processors and importers of plastic ring...

40 CFR 238.10 - Purpose and applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... DEGRADABLE PLASTIC RING CARRIERS General Provisions § 238.10 Purpose and applicability. The purpose of this part is to require that plastic ring carriers be made of degradable materials as described in §§ 238.20 and 238.30. The requirements of this part apply to all processors and importers of plastic ring...

40 CFR 238.10 - Purpose and applicability.

Code of Federal Regulations, 2012 CFR

2012-07-01

... DEGRADABLE PLASTIC RING CARRIERS General Provisions § 238.10 Purpose and applicability. The purpose of this part is to require that plastic ring carriers be made of degradable materials as described in §§ 238.20 and 238.30. The requirements of this part apply to all processors and importers of plastic ring...

40 CFR 238.10 - Purpose and applicability.

Code of Federal Regulations, 2013 CFR

2013-07-01

... DEGRADABLE PLASTIC RING CARRIERS General Provisions § 238.10 Purpose and applicability. The purpose of this part is to require that plastic ring carriers be made of degradable materials as described in §§ 238.20 and 238.30. The requirements of this part apply to all processors and importers of plastic ring...

40 CFR 238.10 - Purpose and applicability.

Code of Federal Regulations, 2014 CFR

2014-07-01

... DEGRADABLE PLASTIC RING CARRIERS General Provisions § 238.10 Purpose and applicability. The purpose of this part is to require that plastic ring carriers be made of degradable materials as described in §§ 238.20 and 238.30. The requirements of this part apply to all processors and importers of plastic ring...

Evaluation of HDPE and LDPE degradation by fungus, implemented by statistical optimization

NASA Astrophysics Data System (ADS)

Ojha, Nupur; Pradhan, Neha; Singh, Surjit; Barla, Anil; Shrivastava, Anamika; Khatua, Pradip; Rai, Vivek; Bose, Sutapa

2017-01-01

Plastic in any form is a nuisance to the well-being of the environment. The ‘pestilence’ caused by it is mainly due to its non-degradable nature. With the industrial boom and the population explosion, the usage of plastic products has increased. A steady increase has been observed in the use of plastic products, and this has accelerated the pollution. Several attempts have been made to curb the problem at large by resorting to both chemical and biological methods. Chemical methods have only resulted in furthering the pollution by releasing toxic gases into the atmosphere; whereas; biological methods have been found to be eco-friendly however they are not cost effective. This paves the way for the current study where fungal isolates have been used to degrade polyethylene sheets (HDPE, LDPE). Two potential fungal strains, namely, Penicillium oxalicum NS4 (KU559906) and Penicillium chrysogenum NS10 (KU559907) had been isolated and identified to have plastic degrading abilities. Further, the growth medium for the strains was optimized with the help of RSM. The plastic sheets were subjected to treatment with microbial culture for 90 days. The extent of degradation was analyzed by, FE-SEM, AFM and FTIR. Morphological changes in the plastic sheet were determined.

Evaluation of HDPE and LDPE degradation by fungus, implemented by statistical optimization.

PubMed

Ojha, Nupur; Pradhan, Neha; Singh, Surjit; Barla, Anil; Shrivastava, Anamika; Khatua, Pradip; Rai, Vivek; Bose, Sutapa

2017-01-04

Plastic in any form is a nuisance to the well-being of the environment. The 'pestilence' caused by it is mainly due to its non-degradable nature. With the industrial boom and the population explosion, the usage of plastic products has increased. A steady increase has been observed in the use of plastic products, and this has accelerated the pollution. Several attempts have been made to curb the problem at large by resorting to both chemical and biological methods. Chemical methods have only resulted in furthering the pollution by releasing toxic gases into the atmosphere; whereas; biological methods have been found to be eco-friendly however they are not cost effective. This paves the way for the current study where fungal isolates have been used to degrade polyethylene sheets (HDPE, LDPE). Two potential fungal strains, namely, Penicillium oxalicum NS4 (KU559906) and Penicillium chrysogenum NS10 (KU559907) had been isolated and identified to have plastic degrading abilities. Further, the growth medium for the strains was optimized with the help of RSM. The plastic sheets were subjected to treatment with microbial culture for 90 days. The extent of degradation was analyzed by, FE-SEM, AFM and FTIR. Morphological changes in the plastic sheet were determined.

Evaluation of HDPE and LDPE degradation by fungus, implemented by statistical optimization

PubMed Central

Ojha, Nupur; Pradhan, Neha; Singh, Surjit; Barla, Anil; Shrivastava, Anamika; Khatua, Pradip; Rai, Vivek; Bose, Sutapa

2017-01-01

Plastic in any form is a nuisance to the well-being of the environment. The ‘pestilence’ caused by it is mainly due to its non-degradable nature. With the industrial boom and the population explosion, the usage of plastic products has increased. A steady increase has been observed in the use of plastic products, and this has accelerated the pollution. Several attempts have been made to curb the problem at large by resorting to both chemical and biological methods. Chemical methods have only resulted in furthering the pollution by releasing toxic gases into the atmosphere; whereas; biological methods have been found to be eco-friendly however they are not cost effective. This paves the way for the current study where fungal isolates have been used to degrade polyethylene sheets (HDPE, LDPE). Two potential fungal strains, namely, Penicillium oxalicum NS4 (KU559906) and Penicillium chrysogenum NS10 (KU559907) had been isolated and identified to have plastic degrading abilities. Further, the growth medium for the strains was optimized with the help of RSM. The plastic sheets were subjected to treatment with microbial culture for 90 days. The extent of degradation was analyzed by, FE-SEM, AFM and FTIR. Morphological changes in the plastic sheet were determined. PMID:28051105

Laboratory Test Methods to Determine the Degradation of Plastics in Marine Environmental Conditions

PubMed Central

Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

2012-01-01

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9 months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break = −66% in 2 years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment. PMID:22737147

Laboratory test methods to determine the degradation of plastics in marine environmental conditions.

PubMed

Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

2012-01-01

In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9 months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break = -66% in 2 years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment.

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

Coleman, R.

Plastics can be made from starchy food waste. This article describes a method by which these plastics break down into harmless chemicals when exposed to sunlight, water or bacteria. Degradable trash bags and agricultural mulch films can replace some of the millions of pounds of nondegradable plastics used each year. Researchers at Argonne National Laboratory developed that involves enzymatically converting potato waste into glucose, fermenting the glucose to lactic acid using bacteria, and then using the lactic acid to construct fully degradable plastics.

Compendium of information on identification and testing of materials for plastic solar thermal collectors

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

McGinniss, V.D.; Sliemers, F.A.; Landstrom, D.K.

1980-07-31

This report is intended to organize and summarize prior and current literature concerning the weathering, aging, durability, degradation, and testing methodologies as applied to materials for plastic solar thermal collectors. Topics covered include (1) rate of aging of polymeric materials; (2) environmental factors affecting performance; (3) evaluation and prediction of service life; (4) measurement of physical and chemical properties; (5) discussion of evaluation techniques and specific instrumentation; (6) degradation reactions and mechanisms; (7) weathering of specific polymeric materials; and (8) exposure testing methodology. Major emphasis has been placed on defining the current state of the art in plastics degradation andmore » on identifying information that can be utilized in applying appropriate and effective aging tests for use in projecting service life of plastic solar thermal collectors. This information will also be of value where polymeric components are utilized in the construction of conventional solar collectors or any application where plastic degradation and weathering are prime factors in material selection.« less

China’s Pursuit of Africa’s Natural Resources, (CSL Issue Paper, Volume 1-09, June 2009)

DTIC Science & Technology

2009-06-01

beyond recovery, and mineral exploitation has generated significant pollution that has rendered agricultural land infertile and given rise to social...heard. Then-South African President Thabo Mbeki cautioned China against dumping its low-cost textile and plastics products in Africa, thus denying...energy-security-asem- beijing -financial-crisis (accessed December 5, 2008). African Politics Portal. 2008. Top Ten Misconceptions about Chinese

Metal uptake by native plants and revegetation potential of mining sulfide-rich waste-dumps.

PubMed

Gomes, Patrícia; Valente, Teresa; Pamplona, Jorge; Braga, Maria Amália Sequeira; Pissarra, José; Gil, José António Grande; de la Torre, Maria Luisa

2014-01-01

Waste dumps resulting from metal exploitation create serious environmental damage, providing soil and water degradation over long distances. Phytostabilization can be used to remediate these mining sites. The present study aims to evaluate the behavior of selected plant species (Erica arborea, Ulex europaeus, Agrostis delicatula, and Cytisus multiflorus) that grow spontaneously in three sulfide-rich waste-dumps (Lapa Grande, Cerdeirinha, and Penedono, Portugal). These sites represent different geological, climatic and floristic settings. The results indicate distinctive levels and types of metal contamination: Penedono presents highest sulfate and metal contents, especially As, with low levels of Fe. In contrast, at Lapa Grande and Cerdeirinha Fe, Mn, and Zn are the dominant metals. In accordance, each waste dump develops a typical plant community, providing a specific vegetation inventory. At Penedono, Agrostis delicatula accumulates As, Pb, Cu, Mn, and Zn, showing higher bioaccumulation factors (BF) for Mn (32.1) and As (24.4). At Cerdeirinha, Ulex europaeus has the highest BF for Pb (984), while at Lapa Grande, Erica arborea presents high BF for Mn (9.8) and Pb (8.1). Regarding TF, low values were obtained for most of the metals, especially As (TF < 1). Therefore, the results obtained from representative plant species suggest appropriate behavior for phytostabilization measures.

Identification and analysis the illegal dumping spot of solid waste at Ciliwung segment 5 riverbanks

NASA Astrophysics Data System (ADS)

Indrawati, D.; Purwaningrum, P.

2018-01-01

Ciliwung River is the main river in the area of Jakarta that is divided into six segments across West Java and Jakarta. The study focuses on the fifth segment which is 30 km long, covering from Kelapa Dua Depok to Manggarai, South Jakarta. The survey of the river consists of 3 sub-segments: Lenteng Agung, Pejaten Timur and Manggarai. Objectives of the study are to describe the characteristics and typology of the residential surrounding the Ciliwung Segment 5 Riverbank, to identification the illegal dumping spot of solid waste, to measure the volume and composition of solid waste in the riverbank, to decide solid waste management for residential area surrounding river banks to control the river pollution. The study shows that there are 11 illegal dumping spot of solid waste consisting of 4.37 m3 solid waste volume. The average composition of solid waste consists of 44% organic, 14% woods, 12% papers, 11% plastics, 3% rubbers, 1% metals and 2% others. To control the river pollution efforts are restoring the function of riverbanks to become green open space area, installing the trash rack into the river, to manage domestic solid waste based on 3R (Reduce, Reuse, Recycle) concept.

Physico-chemical properties of excavated plastic from landfill mining and current recycling routes.

PubMed

Canopoli, L; Fidalgo, B; Coulon, F; Wagland, S T

2018-06-01

In Europe over 5.25 billion tonnes of waste has been landfilled between 1995 and 2015. Among this large amount of waste, plastic represents typically 5-25 wt% which is significant and has the potential to be recycled and reintroduced into the circular economy. To date there is still however little information available of the opportunities and challenges in recovering plastics from landfill sites. In this review, the impacts of landfill chemistry on the degradation and/or contamination of excavated plastic waste are analysed. The feasibility of using excavated plastic waste as feedstock for upcycling to valuable chemicals or liquid fuels through thermochemical conversion is also critically discussed. The limited degradation that is experienced by many plastics in landfills (>20 years) which guarantee that large amount is still available is largely due to thermooxidative degradation and the anaerobic conditions. However, excavated plastic waste cannot be conventionally recycled due to high level of ash, impurities and heavy metals. Recent studies demonstrated that pyrolysis offers a cost effective alternative option to conventional recycling. The produced pyrolysis oil is expected to have similar characteristics to petroleum diesel oil. The production of valuable product from excavated plastic waste will also increase the feasibility of enhanced landfill mining projects. However, further studies are needed to investigate the uncertainties about the contamination level and degradation of excavated plastic waste and address their viability for being processed through pyrolysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

International Space Station External Contamination Status

NASA Technical Reports Server (NTRS)

Mikatarian, Ron; Soares, Carlos

2000-01-01

PResentation slides examine external contamination requirements; International Space Station (ISS) external contamination sources; ISS external contamination sensitive surfaces; external contamination control; external contamination control for pre-launch verification; flight experiments and observations; the Space Shuttle Orbiter waste water dump, materials outgassing, active vacuum vents; example of molecular column density profile, modeling and analysis tools; sources of outgassing induced contamination analyzed to date, quiescent sources, observations on optical degradation due to induced external contamination in LEO; examples of typical contaminant and depth profiles; and status of the ISS system, material outgassing, thruster plumes, and optical degradation.

Plastics and beaches: a degrading relationship.

PubMed

Corcoran, Patricia L; Biesinger, Mark C; Grifi, Meriem

2009-01-01

Plastic debris in Earth's oceans presents a serious environmental issue because breakdown by chemical weathering and mechanical erosion is minimal at sea. Following deposition on beaches, plastic materials are exposed to UV radiation and physical processes controlled by wind, current, wave and tide action. Plastic particles from Kauai's beaches were sampled to determine relationships between composition, surface textures, and plastics degradation. SEM images indicated that beach plastics feature both mechanically eroded and chemically weathered surface textures. Granular oxidation textures were concentrated along mechanically weakened fractures and along the margins of the more rounded plastic particles. Particles with oxidation textures also produced the most intense peaks in the lower wavenumber region of FTIR spectra. The textural results suggest that plastic debris is particularly conducive to both chemical and mechanical breakdown in beach environments, which cannot be said for plastics in other natural settings on Earth.

Isolation of native soil microorganisms with potential for breaking down biodegradable plastic mulch films used in agriculture.

PubMed

Bailes, Graham; Lind, Margaret; Ely, Andrew; Powell, Marianne; Moore-Kucera, Jennifer; Miles, Carol; Inglis, Debra; Brodhagen, Marion

2013-05-10

Fungi native to agricultural soils that colonized commercially available biodegradable mulch (BDM) films were isolated and assessed for potential to degrade plastics. Typically, when formulations of plastics are known and a source of the feedstock is available, powdered plastic can be suspended in agar-based media and degradation determined by visualization of clearing zones. However, this approach poorly mimics in situ degradation of BDMs. First, BDMs are not dispersed as small particles throughout the soil matrix. Secondly, BDMs are not sold commercially as pure polymers, but rather as films containing additives (e.g. fillers, plasticizers and dyes) that may affect microbial growth. The procedures described herein were used for isolates acquired from soil-buried mulch films. Fungal isolates acquired from excavated BDMs were tested individually for growth on pieces of new, disinfested BDMs laid atop defined medium containing no carbon source except agar. Isolates that grew on BDMs were further tested in liquid medium where BDMs were the sole added carbon source. After approximately ten weeks, fungal colonization and BDM degradation were assessed by scanning electron microscopy. Isolates were identified via analysis of ribosomal RNA gene sequences. This report describes methods for fungal isolation, but bacteria also were isolated using these methods by substituting media appropriate for bacteria. Our methodology should prove useful for studies investigating breakdown of intact plastic films or products for which plastic feedstocks are either unknown or not available. However our approach does not provide a quantitative method for comparing rates of BDM degradation.

Isolation of Native Soil Microorganisms with Potential for Breaking Down Biodegradable Plastic Mulch Films Used in Agriculture

PubMed Central

Bailes, Graham; Lind, Margaret; Ely, Andrew; Powell, Marianne; Moore-Kucera, Jennifer; Miles, Carol; Inglis, Debra; Brodhagen, Marion

2013-01-01

Fungi native to agricultural soils that colonized commercially available biodegradable mulch (BDM) films were isolated and assessed for potential to degrade plastics. Typically, when formulations of plastics are known and a source of the feedstock is available, powdered plastic can be suspended in agar-based media and degradation determined by visualization of clearing zones. However, this approach poorly mimics in situ degradation of BDMs. First, BDMs are not dispersed as small particles throughout the soil matrix. Secondly, BDMs are not sold commercially as pure polymers, but rather as films containing additives (e.g. fillers, plasticizers and dyes) that may affect microbial growth. The procedures described herein were used for isolates acquired from soil-buried mulch films. Fungal isolates acquired from excavated BDMs were tested individually for growth on pieces of new, disinfested BDMs laid atop defined medium containing no carbon source except agar. Isolates that grew on BDMs were further tested in liquid medium where BDMs were the sole added carbon source. After approximately ten weeks, fungal colonization and BDM degradation were assessed by scanning electron microscopy. Isolates were identified via analysis of ribosomal RNA gene sequences. This report describes methods for fungal isolation, but bacteria also were isolated using these methods by substituting media appropriate for bacteria. Our methodology should prove useful for studies investigating breakdown of intact plastic films or products for which plastic feedstocks are either unknown or not available. However our approach does not provide a quantitative method for comparing rates of BDM degradation. PMID:23712218

Benthic plastic debris in marine and fresh water environments.

PubMed

Corcoran, Patricia L

2015-08-01

This review provides a discussion of the published literature concerning benthic plastic debris in ocean, sea, lake, estuary and river bottoms throughout the world. Although numerous investigations of shoreline, surface and near-surface plastic debris provide important information on plastic types, distribution, accumulation, and degradation, studies of submerged plastic debris have been sporadic in the past and have become more prominent only recently. The distribution of benthic debris is controlled mainly by combinations of urban proximity and its association with fishing-related activities, geomorphology, hydrological conditions, and river input. High density plastics, biofouled products, polymers with mineral fillers or adsorbed minerals, and plastic-metal composites all have the potential to sink. Once deposited on the bottoms of water basins and channels, plastics are shielded from UV light, thus slowing the degradation process significantly. Investigations of the interactions between benthic plastic debris and bottom-dwelling organisms will help shed light on the potential dangers of submerged plastic litter.

Microplastic Generation in the Marine Environment Through Degradation and Fragmentation

NASA Astrophysics Data System (ADS)

Perryman, M. E.; Jambeck, J.; Woodson, C. B.; Locklin, J.

2016-02-01

Plastic use has become requisite in our global economy; as population continues to increase, so too, will plastic production. At its end-of-life, some amount of plastic is mismanaged and ends up in the ocean. Once there, various environmental stresses eventually fragment plastic into microplastic pieces, now ubiquitous in the marine environment. Microplastics pose a serious threat to marine biota and possibly humans. Though the general mechanisms of microplastic formation are known, the rate and extent is not. Currently, no standard methodology for testing the formation of microplastic exists. We developed a replicable and flexible methodology for testing the formation of microplastics. We used this methodology to test the effects of UV, thermal, and mechanical stress on various types of plastic. We tested for fragmentation by measuring weight and size distribution, and looked for signs of degraded plastic using Fourier transform infrared spectroscopy. Though our results did not find any signs of fragmentation, we did see degradation. Additionally, we established a sound methodology and provided a benchmark for additional studies.

Assessment and quantification of plastics waste generation in major 60 cities of India.

PubMed

Nalini, R; Srinivasulu, B; Shit, Subhas C; Nigam, Suneel Kumar; Akolkar, A B; Dwivedfi, R K

2013-04-01

Polymers or plastics materials registered rapid growth in 1970s, 1980s and 1990s at the rate of 2-2.5 times the GDP growth in India. The demand for plastic raw material got more than doubled from 3.3 Million Metric Ton to 6.8 Million Metric Tons in 2010 attributed mainly to rapid urbanization, spread of retail chains, plastics based packaging from grocery to food and vegetable products to cosmetics and consumer items. Plastics packages have its merits over many of conventional materials in the related sector but unless they are collected back effectively after their use to go into recycling process, they become an eyesore in the stream of Municipal Solid Waste (MSW) due to high visibility. As the synthetic and conventional plastics are non-biodegradable in nature, these remain in the dump yards/ landfills for several years, if not collected properly. Due to non- biodegradability, plastics waste remains in the environment for several years, if not collected and disposing plastics wastes at landfills are unsafe since toxic chemicals leach out into the soil and as they contaminate soil and underground water quality. The municipal solid waste also increasing day-by-day due to the inefficient source collection, segregation and transmission of plastics waste for recycling and reusing. In order to find out the realistic plastics waste generation, a study on assessment and quantification of plastics waste has been carried out by CPCB in collaboration with CIPET on selected 60 major cities of India.

Microbial degradation of high impact polystyrene (HIPS), an e-plastic with decabromodiphenyl oxide and antimony trioxide.

PubMed

Sekhar, Vini C; Nampoothiri, K Madhavan; Mohan, Arya J; Nair, Nimisha R; Bhaskar, Thallada; Pandey, Ashok

2016-11-15

Accumulation of electronic waste has increased catastrophically and out of that various plastic resins constitute one of the leading thrown out materials in the electronic machinery. Enrichment medium, containing high impact polystyrene (HIPS) with decabromodiphenyl oxide and antimony trioxide as sole carbon source, was used to isolate microbial cultures. The viability of these cultures in the e-plastic containing mineral medium was further confirmed by triphenyl tetrazolium chloride (TTC) reduction test. Four cultures were identified by 16S rRNA sequencing as Enterobacter sp., Citrobacter sedlakii, Alcaligenes sp. and Brevundimonas diminuta. Biodegradation experiments were carried out in flask level and gelatin supplementation (0.1% w/v) along with HIPS had increased the degradation rate to a maximum of 12.4% (w/w) within 30days. This is the first report for this kind of material. The comparison of FTIR, NMR, and TGA analysis of original and degraded e-plastic films revealed structural changes under microbial treatment. Polystyrene degradation intermediates in the culture supernatant were also detected using HPLC analysis. The gravity of biodegradation was validated by morphological changes under scanning electron microscope. All isolates displayed depolymerase activity to substantiate enzymatic degradation of e-plastic. Copyright © 2016 Elsevier B.V. All rights reserved.

Biodegradation of Polyethylene and Plastic Mixtures in Mealworms (Larvae of Tenebrio molitor) and Effects on the Gut Microbiome.

PubMed

Brandon, Anja Malawi; Gao, Shu-Hong; Tian, Renmao; Ning, Daliang; Yang, Shan-Shan; Zhou, Jizhong; Wu, Wei-Min; Criddle, Craig S

2018-06-05

Recent studies have demonstrated the ability for polystyrene (PS) degradation within the gut of mealworms ( Tenebrio molitor). To determine whether plastics may be broadly susceptible to biodegradation within mealworms, we evaluated the fate of polyethylene (PE) and mixtures (PE + PS). We find that PE biodegrades at comparable rates to PS. Mass balances indicate conversion of up 49.0 ± 1.4% of the ingested PE into a putative gas fraction (CO 2 ). The molecular weights ( M n ) of egested polymer residues decreased by 40.1 ± 8.5% in PE-fed mealworms and by 12.8 ± 3.1% in PS-fed mealworms. NMR and FTIR analyses revealed chemical modifications consistent with degradation and partial oxidation of the polymer. Mixtures likewise degraded. Our results are consistent with a nonspecific degradation mechanism. Analysis of the gut microbiome by next-generation sequencing revealed two OTUs ( Citrobacter sp. and Kosakonia sp.) strongly associated with both PE and PS as well as OTUs unique to each plastic. Our results suggest that adaptability of the mealworm gut microbiome enables degradation of chemically dissimilar plastics.

Chemical Munitions Search & Assessment-An evaluation of the dumped munitions problem in the Baltic Sea

NASA Astrophysics Data System (ADS)

Bełdowski, Jacek; Klusek, Zygmunt; Szubska, Marta; Turja, Raisa; Bulczak, Anna I.; Rak, Daniel; Brenner, Matthias; Lang, Thomas; Kotwicki, Lech; Grzelak, Katarzyna; Jakacki, Jaromir; Fricke, Nicolai; Östin, Anders; Olsson, Ulf; Fabisiak, Jacek; Garnaga, Galina; Nyholm, Jenny Rattfelt; Majewski, Piotr; Broeg, Katja; Söderström, Martin; Vanninen, Paula; Popiel, Stanisław; Nawała, Jakub; Lehtonen, Kari; Berglind, Rune; Schmidt, Beata

2016-06-01

Chemical Munitions Search & Assessment (CHEMSEA) project has performed studies on chemical weapon (CW) detection, sediment pollution and spreading as well as biological effects of chemical warfare agents (CWAs) dumped in the Baltic Sea. Results suggest that munitions containing CWAs are more scattered on the seafloor than suspected, and previously undocumented dumpsite was discovered in Gdansk Deep. Pollution of sediments with CWA degradation products was local and close to the detected objects; however the pollution range was larger than predicted with theoretical models. Bottom currents observed in the dumpsites were strong enough for sediment re-suspension, and contributed to the transport of polluted sediments. Diversity and density of the faunal communities were poor at the dumping sites in comparison to the reference area, although the direct effects of CWA on benthos organisms were difficult to determine due to hypoxic or even anoxic conditions near the bottom. Equally, the low oxygen might have affected the biological effects assessed in cod and caged blue mussels. Nonetheless, both species showed significantly elevated molecular and cellular level responses at contaminated sites compared to reference sites.

A qualitative screening and quantitative measurement of organic contaminants on different types of marine plastic debris.

PubMed

Gauquie, Johanna; Devriese, Lisa; Robbens, Johan; De Witte, Bavo

2015-11-01

Chemical compounds present on plastic were characterised on different types of plastic litter and beached pellets, using a general GC-MS screening method. A variety of plastic related compounds, such as building blocks, antioxidants, additives and degradation products, were identified next to diverse environmental pollutants and biofilm compounds. A validated method for the analysis of PAHs and PCBs on beached pellets at the Belgian Coast, showed concentrations of ∑ 16 EPA-PAHs of 1076-3007 ng g(-1) plastic, while the concentrations of ∑ 7 OSPAR-PCBs ranged from 31 to 236 ng g(-1) plastic. The wide variety of plastic compounds retrieved in the general screening showed the importance of plastic as a potential source of contaminants and their degradation products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Assessing the effect of biodegradable and degradable plastics on the composting of green wastes and compost quality.

PubMed

Unmar, G; Mohee, R

2008-10-01

An assessment of the effect of the composting potential of Mater-Bi biodegradable plastic with green wastes, noted by GBIO, and degradable plastic (PDQ-H additive) with green wastes, noted by GDEG, was carried out in a lagged two-compartment compost reactor. The composting time was determined until constant mass of the composting substrates was reached. The green wastes composting process was used as control (G). After one week of composting, the biodegradable plastics disappeared completely, while 2% of the original degradable plastic still remained after about 8 weeks of composting. A net reduction in volatile solids contents of 61.8%, 56.5% and 53.2% were obtained for G, GBIO and GDEG, respectively. Compost quality was assessed in terms of nitrogen, potassium and phosphorus contents, which were found to be highest for GBIO compost. From the phytotoxicity test, it has been observed that a diluted extract of GBIO compost has produced the longest length of radicle. From the respiration test, no significant difference in the amount of carbon dioxide released by the composting of GDEG and G was observed. This study showed that the quality of the compost is not affected by the presence of the biodegradable and degradable plastics in the raw materials.

Bacterial diversity and real-time PCR based assessment of linA and linB gene distribution at hexachlorocyclohexane contaminated sites.

PubMed

Lal, Devi; Jindal, Swati; Kumari, Hansi; Jit, Simran; Nigam, Aeshna; Sharma, Pooja; Kumari, Kirti; Lal, Rup

2015-03-01

The disposal of hexachlorocyclohexane (HCH) muck has created large number of HCH dumpsites all over the world from where the harmful HCH isomers are leaking into the environment. Bacteria have evolved at such contaminated sites that have the ability to degrade HCH. Degradation of various HCH isomers in bacterial strains is mediated primarily by two genes: linA and linB which encode dehydrochlorinase and haloalkane dehalogenase respectively. In this study we explored one such highly contaminated HCH dumpsite located in Lucknow, Uttar Pradesh, India. To assess the biostimulation potential of the contaminated site, microbial diversity study and real-time PCR based quantification of lin genes was carried out. The soil samples from dumpsite and surrounding areas were found to be highly contaminated with HCH residue levels as high as 1.8 × 10(5)  mg kg(-1). The residues were detected in areas upto 13 km from the dumpsite. Sphingomonads, Chromohalobacter, and Marinobacter were the dominant genera present at the dump-site. Role of Sphingomonads in HCH degradation has been well documented. The highest copy numbers of linA and linB genes as determined using real-time PCR were 6.2 × 10(4) and 5.3 × 10(5), respectively, were found in sample from the dump site. The presence of Sphingomonads, linA, and linB genes from HCH contaminated soil indicates the presence of indigenous bacterial communities capable of HCH degradation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of colorant and film thickness on thermal aging characteristics of oxo-biodegradable plastic bags

NASA Astrophysics Data System (ADS)

Leuterio, Giselle Lou D.; Pajarito, Bryan B.; Domingo, Carla Marie C.; Lim, Anna Patricia G.

2016-05-01

Functional, lightweight, strong and cheap plastic bags incorporated with pro-oxidants undergo accelerated degradation under exposure to heat and oxygen. This work investigated the effect of colorant and film thickness on thermal aging characteristics of commercial oxo-biodegradable plastic bag films at 70 °C. Degradation is monitored through changes in infrared absorption, weight, and tensile properties of thermally aged films. The presence of carbonyl band in infrared spectrum after 672 h of thermal aging supports the degradation behavior of exposed films. Results show that incorporation of colorant and increasing thickness exhibit low maximum weight uptake. Titanium dioxide as white colorant in films lowers the susceptibility of films to oxygen uptake but enhances physical degradation. Higher amount of pro-oxidant loading also contributes to faster degradation. Opaque films are characterized by low tensile strength and high elastic modulus. Decreasing the thickness contributes to lower tensile strength of films. Thermally aged films with colorant and low thickness promote enhanced degradation.

Biodegradation of Degradable Plastic Polyethylene by Phanerochaete and Streptomyces Species †

PubMed Central

Lee, Byungtae; Pometto, Anthony L.; Fratzke, Alfred; Bailey, Theodore B.

1991-01-01

The ability of lignin-degrading microorganisms to attack degradable plastics was investigated in pure shake flask culture studies. The degradable plastic used in this study was produced commercially by using the Archer-Daniels-Midland POLYCLEAN masterbatch and contained pro-oxidant and 6% starch. The known lignin-degrading bacteria Streptomyces viridosporus T7A, S. badius 252, and S. setonii 75Vi2 and fungus Phanerochaete chrysosporium were used. Pro-oxidant activity was accelerated by placing a sheet of plastic into a drying oven at 70°C under atmospheric pressure and air for 0, 4, 8, 12, 16, or 20 days. The effect of 2-, 4-, and 8-week longwave UV irradiation at 365 nm on plastic biodegradability was also investigated. For shake flask cultures, plastics were chemically disinfected and incubated-shaken at 125 rpm at 37°C in 0.6% yeast extract medium (pH 7.1) for Streptomyces spp. and at 30°C for the fungus in 3% malt extract medium (pH 4.5) for 4 weeks along with an uninoculated control for each treatment. Weight loss data were inconclusive because of cell mass accumulation. For almost every 70°C heat-treated film, the Streptomyces spp. demonstrated a further reduction in percent elongation and polyethylene molecular weight average when compared with the corresponding uninoculated control. Significant (P < 0.05) reductions were demonstrated for the 4- and 8-day heat-treated films by all three bacteria. Heat-treated films incubated with P. chrysosporium consistently demonstrated higher percent elongation and molecular weight average than the corresponding uninoculated controls, but were lower than the corresponding zero controls (heat-treated films without 4-week incubation). The 2- and 4-week UV-treated films showed the greatest biodegradation by all three bacteria. Virtually no degradation by the fungus was observed. To our knowledge, this is the first report demonstrating bacterial degradation of these oxidized polyethylenes in pure culture. PMID:16348434

Biodegradation of degradable plastic polyethylene by phanerochaete and streptomyces species.

PubMed

Lee, B; Pometto, A L; Fratzke, A; Bailey, T B

1991-03-01

The ability of lignin-degrading microorganisms to attack degradable plastics was investigated in pure shake flask culture studies. The degradable plastic used in this study was produced commercially by using the Archer-Daniels-Midland POLYCLEAN masterbatch and contained pro-oxidant and 6% starch. The known lignin-degrading bacteria Streptomyces viridosporus T7A, S. badius 252, and S. setonii 75Vi2 and fungus Phanerochaete chrysosporium were used. Pro-oxidant activity was accelerated by placing a sheet of plastic into a drying oven at 70 degrees C under atmospheric pressure and air for 0, 4, 8, 12, 16, or 20 days. The effect of 2-, 4-, and 8-week longwave UV irradiation at 365 nm on plastic biodegradability was also investigated. For shake flask cultures, plastics were chemically disinfected and incubated-shaken at 125 rpm at 37 degrees C in 0.6% yeast extract medium (pH 7.1) for Streptomyces spp. and at 30 degrees C for the fungus in 3% malt extract medium (pH 4.5) for 4 weeks along with an uninoculated control for each treatment. Weight loss data were inconclusive because of cell mass accumulation. For almost every 70 degrees C heat-treated film, the Streptomyces spp. demonstrated a further reduction in percent elongation and polyethylene molecular weight average when compared with the corresponding uninoculated control. Significant (P < 0.05) reductions were demonstrated for the 4- and 8-day heat-treated films by all three bacteria. Heat-treated films incubated with P. chrysosporium consistently demonstrated higher percent elongation and molecular weight average than the corresponding uninoculated controls, but were lower than the corresponding zero controls (heat-treated films without 4-week incubation). The 2- and 4-week UV-treated films showed the greatest biodegradation by all three bacteria. Virtually no degradation by the fungus was observed. To our knowledge, this is the first report demonstrating bacterial degradation of these oxidized polyethylenes in pure culture.

Bitter bonanza in Wyoming

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

Randall, D.

Mineral and energy-related exploration, such as the drilling activity in the Overthrust Belt for petroleum, has made Wyoming a leading energy supplier in the U.S. The energy boom has had many unfortunate effects on the state's environment. Environmental degradation caused by exploration and production in Wyoming includes loss of habitat, poaching of wildlife, water pollution from oil dumping and erosion, and impacts from squatter's camps.

Study of the influence of ZnO addition on the properties of chitosan-banana starch bioplastics

NASA Astrophysics Data System (ADS)

Sapei, L.; Padmawijaya, K. S.; Sijayanti, O.; Wardhana, P. J.

2017-07-01

Plastics have been widely used in our daily life due to their relatively low cost and practical uses. However, plastics are hardly degraded and thus creating lots of environmental problems. Bioplastics have been developed in order to replace the conventional plastics since they are easily degraded and environmentally friendly. In this research, chitosan-banana starch bioplastics were made with the ratio of 70:30 in the presence of 30% glycerol as the plasticizer. ZnO with varying concentrations of 1, 3, and 5% were added into the biopolymer mixtures before casting in order to improve their mechanical properties. It turned out that 3% ZnO significantly increased the bioplastics tensile strength up to ~36MPa. Vice versa, elongation and swelling percentage were decreased as ZnO concentrations increased. Bioplastics prepared with 3% ZnO were degraded within relatively short time in 90 min. These chitosan-banana starch bioplastics reinforced by ZnO seems quite promising to substitute some commercial conventional plastics.

Bioenergy | NREL

Science.gov Websites

Bioenergy Two men in a laboratory, one is holding a plastic bottle. An international research team plastics. Read more about improving plastic-degrading enzymes One man stands behind some laboratory

Plastics in soil: Analytical methods and possible sources.

PubMed

Bläsing, Melanie; Amelung, Wulf

2018-01-15

At least 300 Mio t of plastic are produced annually, from which large parts end up in the environment, where it persists over decades, harms biota and enters the food chain. Yet, almost nothing is known about plastic pollution of soil; hence, the aims of this work are to review current knowledge on i) available methods for the quantification and identification of plastic in soil, ii) the quantity and possible input pathways of plastic into soil, (including first preliminary screening of plastic in compost), and iii) its fate in soil. Methods for plastic analyses in sediments can potentially be adjusted for application to soil; yet, the applicability of these methods for soil needs to be tested. Consequently, the current data base on soil pollution with plastic is still poor. Soils may receive plastic inputs via plastic mulching or the application of plastic containing soil amendments. In compost up to 2.38-1200mg plastic kg -1 have been found so far; the plastic concentration of sewage sludge varies between 1000 and 24,000 plastic items kg -1 . Also irrigation with untreated and treated wastewater (1000-627,000 and 0-125,000 plastic items m -3 , respectively) as well as flooding with lake water (0.82-4.42 plastic items m -3 ) or river water (0-13,751 items km -2 ) can provide major input pathways for plastic into soil. Additional sources comprise littering along roads and trails, illegal waste dumping, road runoff as well as atmospheric input. With these input pathways, plastic concentrations in soil might reach the per mill range of soil organic carbon. Most of plastic (especially >1μm) will presumably be retained in soil, where it persists for decades or longer. Accordingly, further research on the prevalence and fate of such synthetic polymers in soils is urgently warranted. Copyright © 2017 Elsevier B.V. All rights reserved.

Fungal biodegradation of lignopolystyrene graft copolymers. [Pleurotus ostreatus; Phanerochaete chrysosporium; Trametes versicolor; Gloeophyllum trabeum

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

Milstein, O.; Gersonde, R.; Huttermann, A.

1992-10-01

White rot basidiomycetes were able to biodegrade styrene (1-phenylethene) graft copolymers of lignin containing different proportions of lignin and polystyrene (poly(1-phenylethylene)). The biodegradation tests were run on lignin-styrene copolymerization products which contained 10.3, 32.2, and 50.4{percent} (wt/wt) lignin. The polymer samples were incubated with the white rot fungi Pleurotus ostreatus, Phanerochaete chrysosporium, and Trametes versicolor and the brown rot fungus Gloeophyllum trabeum. White rot fungi degraded the plastic samples at a rate which increased with increasing lignin content in the copolymer sample. Both polystyrene and lignin components of the copolymer were readily degraded. Polystyrene pellets were not degradable in thesemore » tests. Degradation was verified for both incubated and control samples by weight loss, quantitative UV spectrophotometric analysis of both lignin and styrene residues, scanning electron microscopy of the plastic surface, and the presence of enzymes active in degradation during incubation. Brown rot fungus did not affect any of the plastics. White rot fungi produced and secreted oxidative enzymes associated with lignin degradation in liquid media during incubation with lignin-polystyrene copolymer.« less

Surface properties of beached plastics.

PubMed

Fotopoulou, Kalliopi N; Karapanagioti, Hrissi K

2015-07-01

Studying plastic characteristics in the marine environment is important to better understand interaction between plastics and the environment. In the present study, high-density polyethylene (HDPE), polyethylene terephalate (PET), and polyvinyl chloride (PVC) samples were collected from the coastal environment in order to study their surface properties. Surface properties such as surface functional groups, surface topography, point of zero charge, and color change are important factors that change during degradation. Eroded HDPE demonstrated an altered surface topography and color and new functional groups. Eroded PET surface was uneven, yellow, and occasionally, colonized by microbes. A decrease in Fourier transform infrared (FTIR) peaks was observed for eroded PET suggesting that degradation had occurred. For eroded PVC, its surface became more lamellar and a new FTIR peak was observed. These surface properties were obtained due to degradation and could be used to explain the interaction between plastics, microbes, and pollutants.

Degradation of biodegradable plastic mulch films in soil environment by phylloplane fungi isolated from gramineous plants.

PubMed

Koitabashi, Motoo; Noguchi, Masako T; Sameshima-Yamashita, Yuka; Hiradate, Syuntaro; Suzuki, Ken; Yoshida, Shigenobu; Watanabe, Takashi; Shinozaki, Yukiko; Tsushima, Seiya; Kitamoto, Hiroko K

2012-08-02

To improve the biodegradation of biodegradable plastic (BP) mulch films, 1227 fungal strains were isolated from plant surface (phylloplane) and evaluated for BP-degrading ability. Among them, B47-9 a strain isolated from the leaf surface of barley showed the strongest ability to degrade poly-(butylene succinate-co-butylene adipate) (PBSA) and poly-(butylene succinate) (PBS) films. The strain grew on the surface of soil-mounted BP films, produced breaks along the direction of hyphal growth indicated that it secreted a BP-degrading enzyme, and has directly contributing to accelerating the degradation of film. Treatment with the culture filtrate decomposed 91.2 wt%, 23.7 wt%, and 14.6 wt% of PBSA, PBS, and commercially available BP polymer blended mulch film, respectively, on unsterlized soil within 6 days. The PCR-DGGE analysis of the transition of soil microbial community during film degradation revealed that the process was accompanied with drastic changes in the population of soil fungi and Acantamoeba spp., as well as the growth of inoculated strain B47-9. It has a potential for application in the development of an effective method for accelerating degradation of used plastics under actual field conditions.

Mechanical characterization of municipal solid waste from two waste dumps at Delhi, India.

PubMed

Ramaiah, B J; Ramana, G V; Datta, Manoj

2017-10-01

The article presents the physical and mechanical properties of the emplaced municipal solid waste (MSW) recovered from different locations of the Ghazipur and Okhla dumps both located at Delhi, India. Mechanical compressibility and shear strength of the collected MSW were evaluated using a 300×300mm direct shear (DS) shear box. Compression ratio (C c ') of MSW at these two dumps varied between 0.11 and 0.17 and is falling on the lower bound of the range (0.1-0.5) of the data reported in the literature for MSW. Low C c ' of MSW is attributed to the relatively low percentages of compressible elements such as textiles, plastics and paper, coupled with relatively high percentages of inert materials such as soil-like and gravel sized fractions. Shear strength of MSW tested is observed to be displacement dependent. The mobilized shear strength parameters i.e., the apparent cohesion intercept (c') and friction angle (ϕ') of MSW at these two dumps are best characterized by c'=13kPa and ϕ'=23° at 25mm displacement and c'=17kPa and ϕ'=34° at 55mm displacement and are in the range reported for MSW in the literature. A large database on the shear strength of MSW from 18 countries that includes: the experimental data from 277 large-scale DS tests (in-situ and laboratory) and the data from back analysis of 11 failed landfill slopes is statistically analyzed. Based on the analysis, a simple linear shear strength envelope, characterized by c'=17kPa and ϕ'=32°, is proposed for MSW for preliminary use in the absence of site-specific data for stability evaluation of the solid waste landfill under drained conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Illegal Dumping of Toxic Waste and Its Effect on Human Health in Campania, Italy

PubMed Central

Mazza, Alfredo; Piscitelli, Prisco; Neglia, Cosimo; Rosa, Giulia Della; Iannuzzi, Leopoldo

2015-01-01

The region of Campania (particularly Naples and Caserta) has experienced an emergency in the waste management cycle during past years. Although the most critical phase has been overcome after the construction of the incineration plant in Acerra (an old-fashioned technology built up over a few months, whose impact on environment and health has not yet been assessed), most of the underlying problems have not been resolved. The illegal burning of wheels, plastics, textiles, and other industrial residuals, along with the detection of two thousand toxic substance dumping sites, still represents major concerns of environmental pollution and population health. This review summarizes the most relevant studies, which analyzed chemical contamination (primarily dioxins and polychlorinated biphenyls (PCBs)) of the air, soil, water, animals, and humans in Campania. In addition, we reviewed information on population health (i.e., mortality data, congenital malformations, and cancer incidence). Moving from a detailed mapping of (mostly illegal) waste dumping sites in Campania, we have focused on recent studies which have found: (a) high concentrations of dioxins (≥5.0 pg TEQ/g fat) in milk samples from sheep, cows, and river buffaloes; (b) remarkable contamination of dioxin and PCBs in human milk samples from those living in the Naples and Caserta areas (PCDDs+PCDFs and dioxin-like-PCBs (dl-PCBs) assessed at 16.6 pg TEQ/g of fat; range: 7.5–43 pg/g of fat); (c) potential age-adjusted standardized mortality rates associated with some specific cancer types; (d) a statistically significant association between exposure to illegal toxic waste dumping sites and cancer mortality, even after adjustment by socio-economic factors and other environmental indicators. PMID:26086704

Illegal Dumping of Toxic Waste and Its Effect on Human Health in Campania, Italy.

PubMed

Mazza, Alfredo; Piscitelli, Prisco; Neglia, Cosimo; Della Rosa, Giulia; Iannuzzi, Leopoldo

2015-06-16

The region of Campania (particularly Naples and Caserta) has experienced an emergency in the waste management cycle during past years. Although the most critical phase has been overcome after the construction of the incineration plant in Acerra (an old-fashioned technology built up over a few months, whose impact on environment and health has not yet been assessed), most of the underlying problems have not been resolved. The illegal burning of wheels, plastics, textiles, and other industrial residuals, along with the detection of two thousand toxic substance dumping sites, still represents major concerns of environmental pollution and population health. This review summarizes the most relevant studies, which analyzed chemical contamination (primarily dioxins and polychlorinated biphenyls (PCBs)) of the air, soil, water, animals, and humans in Campania. In addition, we reviewed information on population health (i.e., mortality data, congenital malformations, and cancer incidence). Moving from a detailed mapping of (mostly illegal) waste dumping sites in Campania, we have focused on recent studies which have found: (a) high concentrations of dioxins (≥5.0 pg TEQ/g fat) in milk samples from sheep, cows, and river buffaloes; (b) remarkable contamination of dioxin and PCBs in human milk samples from those living in the Naples and Caserta areas (PCDDs+PCDFs and dioxin-like-PCBs (dl-PCBs) assessed at 16.6 pg TEQ/g of fat; range: 7.5-43 pg/g of fat); (c) potential age-adjusted standardized mortality rates associated with some specific cancer types; (d) a statistically significant association between exposure to illegal toxic waste dumping sites and cancer mortality, even after adjustment by socio-economic factors and other environmental indicators.

The BDX experiment at Jefferson Laboratory

NASA Astrophysics Data System (ADS)

Celentano, Andrea

2015-06-01

The existence of MeV-GeV dark matter (DM) is theoretically well motivated but remarkably unexplored. The Beam Dump eXperiment (BDX) at Jefferson Laboratory aims to investigate this mass range. Dark matter particles will be detected trough scattering on a segmented, plastic scintillator detector placed downstream of the beam-dump at one of the high intensity JLab experimental Halls. The experiment will collect up to 1022 electrons-on-target (EOT) in a one-year period. For these conditions, BDX is sensitive to the DM-nucleon elastic scattering at the level of a thousand counts per year, and is only limited by cosmogenic backgrounds. The experiment is also sensitive to DM-electron elastic and inelastic scattering, at the level of 10 counts/year. The foreseen signal for these channels is an high-energy (> 100 MeV) electromagnetic shower, with almost no background. The experiment, has been presented in form of a Letter of Intent to the laboratory, receiving positive feedback, and is currently being designed.

The effect of starch-garlic powder ratio on degradation rate of Gadung starch bioplastic

NASA Astrophysics Data System (ADS)

Mairiza, L.; Mariana; Ramadhany, M.; Feviyussa, C. A.

2018-03-01

Bioplastic is one of the solutions for environmental problems caused by plastics waste. Utilization of toxic gadung starch in the manufacturing of bioplastic would be as an alternative, due to gadung bulb has high starch content, and it is still not used optimally. This research aimed to learn about the using of gadung starch-mixed with garlic powder of making biodegradable plastic packaging. Also, to observe the duration of degradation, as a level of biodegradability of plastic film produced. The method used making this bioplastic was casting method. The variables used in this study were the ratios of starch and powdered garlic, were 10:0; 8:2; 6:4, and the concentration of garlic powder were 2%; 4%; 6%; and 8 %. The degradation test was done by soil burial test. The results of the soil burial test shown that the film was more rapidly degraded at ratio of 6: 4 compared to the ratio of 8: 2 and 10: 0. The results shown that bioplastic at the starch-garlic powder ratio of 10: 0 was decomposed in 21 days, at the the ratio of 8:2 was 15 days, while at the ratio of 6:4, the plastic film was degraded in the 11 days.

Protein Degradation by Ubiquitin-Proteasome System in Formation and Labilization of Contextual Conditioning Memory

ERIC Educational Resources Information Center

Fustiñana, María Sol; de la Fuente, Verónica; Federman, Noel; Freudenthal, Ramiro; Romano, Arturo

2014-01-01

The ubiquitin-proteasome system (UPS) of protein degradation has been evaluated in different forms of neural plasticity and memory. The role of UPS in such processes is controversial. Several results support the idea that the activation of this system in memory consolidation is necessary to overcome negative constrains for plasticity. In this…

Study of waste management towards sustainable green campus in Universitas Gadjah Mada

NASA Astrophysics Data System (ADS)

Setyowati, Mega; Kusumawanto, Arif; Prasetya, Agus

2018-05-01

Waste management is a part of the green campus achievement program. Universitas Gadjah Mada has a Standard Operating Procedure for managing produced waste. Waste produced by each building or work unit is temporarily accommodated in the waste depot before dumped into the landfill. This research aims to study the waste management system in UGM, in accordance with the concept of a green campus. The concept of green campus to improve the efficiency of waste management needs to be supported by various parties. The success of the green campus program relies on an integrated approach, a sustainable implementation that involves stakeholders of the university. In actualizing the concept of a green campus, the university has its own waste processing system. The organic produced waste is processed into compost, while plastic waste is converted into alternative fuel. Overall, the waste management system that UGM owns is ineffective and inefficient, it was proved by the fact that there is still much waste dumped into the landfill. UGM provides a laboratory that is specialized to process waste that is produced by UGM. It is planned to be able to reduce the amount of waste that is dumped into the landfill. According to the results, vermicomposting technology, the manufacture of liquid fertilizer from leachate, and the manufacture of the composite from a mixture of leaves and paper were offered as solutions.

A review of plastic waste biodegradation.

PubMed

Zheng, Ying; Yanful, Ernest K; Bassi, Amarjeet S

2005-01-01

With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.

Bio-based and biodegradable plastics for use in crop production.

PubMed

Riggi, Ezio; Santagata, Gabriella; Malinconico, Mario

2011-01-01

The production and management of crops uses plastics for many applications (e.g., low tunnels, high tunnels, greenhouses, mulching, silage bags, hay bales, pheromone traps, coatings of fertilizers or pesticides or hormones or seeds, and nursery pots and containers for growing transplants). All these applications have led some authors to adopt the term "plasticulture" when discussing the use of plastic materials in agriculture and related industries. Unfortunately, the sustainability of this use of plastics is low, and renewability and degradability have become key words in the debate over sustainable production and utilization of plastic. Recently, researchers and the plastics industry have made strong efforts (i) to identify new biopolymers and natural additives from renewable sources that can be used in plastics production and (ii) to enhance the degradability (biological or physical) of the new ecologically sustainable materials. In the present review, we describe the main research results, current applications, patents that have been applied for in the last two decades, and future perspectives on sustainable use of plastics to support crop production. The article presents some promising patents on bio-based and biodegradable plastics for use in crop production.

Plastics in the Ocean: More Than a Litter Problem.

ERIC Educational Resources Information Center

Center for Environmental Education, Washington, DC.

Environmental impacts arise from entanglement of marine animals in plastic debris and from ingestion of plastics by marine organisms. Plastic debris can cause potential threats to humans when divers become entangled or vessels become fouled in debris. The depletion of fishery resources, vessel damage, and aesthetic degradation resulting in lost…

Isolation of a selected microbial consortium capable of degrading methyl parathion and p-nitrophenol from a contaminated soil site.

PubMed

Pino, Nancy J; Dominguez, Maria C; Penuela, Gustavo A

2011-01-01

A bacterial consortium with the ability to degrade methyl parathion and p-nitrophenol, using these compounds as the only carbon source, was obtained by selective enrichment in a medium with methyl parathion. Samples were taken from Moravia, Medellin; an area that is highly contaminated, owing to the fact that it was used as a garbage dump from 1974 to 1982. Acinetobacter sp, Pseudomonas putida, Bacillus sp, Pseudomonas aeruginosa Citrobacter freundii, Stenotrophomonas sp, Flavobacterium sp, Proteus vulgaris, Pseudomonas sp, Acinetobacter sp, Klebsiella sp and Proteus sp were the microorganisms identified within the consortium. In culture, the consortium was able to degrade 150 mg L⁻¹ of methyl-parathion and p-nitrophenol in 120 h, but after adding glucose or peptone to the culture, the time of degradation decreased to 24 h. In soil, the consortium was also able to degrade 150 mg L⁻¹ of methyl parathion in 120 h at different depths and also managed to decrease the toxicity.

Self-actuating and self-diagnosing plastically deforming piezo-composite flapping wing MAV

NASA Astrophysics Data System (ADS)

Harish, Ajay B.; Harursampath, Dineshkumar; Mahapatra, D. Roy

2011-04-01

In this work, we propose a constitutive model to describe the behavior of Piezoelectric Fiber Reinforced Composite (PFRC) material consisting of elasto-plastic matrix reinforced by strong elastic piezoelectric fibers. Computational efficiency is achieved using analytical solutions for elastic stifness matrix derived from Variational Asymptotic Methods (VAM). This is extended to provide Structural Health Monitoring (SHM) based on plasticity induced degradation of flapping frequency of PFRC. Overall this work provides an effective mathematical tool that can be used for structural self-health monitoring of plasticity induced flapping degradation of PFRC flapping wing MAVs. The developed tool can be re-calibrated to also provide SHM for other forms of failures like fatigue, matrix cracking etc.

Degradation of biodegradable plastic mulch films in soil environment by phylloplane fungi isolated from gramineous plants

PubMed Central

2012-01-01

To improve the biodegradation of biodegradable plastic (BP) mulch films, 1227 fungal strains were isolated from plant surface (phylloplane) and evaluated for BP-degrading ability. Among them, B47-9 a strain isolated from the leaf surface of barley showed the strongest ability to degrade poly-(butylene succinate-co-butylene adipate) (PBSA) and poly-(butylene succinate) (PBS) films. The strain grew on the surface of soil-mounted BP films, produced breaks along the direction of hyphal growth indicated that it secreted a BP-degrading enzyme, and has directly contributing to accelerating the degradation of film. Treatment with the culture filtrate decomposed 91.2 wt%, 23.7 wt%, and 14.6 wt% of PBSA, PBS, and commercially available BP polymer blended mulch film, respectively, on unsterlized soil within 6 days. The PCR-DGGE analysis of the transition of soil microbial community during film degradation revealed that the process was accompanied with drastic changes in the population of soil fungi and Acantamoeba spp., as well as the growth of inoculated strain B47-9. It has a potential for application in the development of an effective method for accelerating degradation of used plastics under actual field conditions. PMID:22856640

H. R. 2538: A bill to amend the Federal Water Pollution Control Act, introduced in the US House of Representatives, One Hundred Second Congress, First Session, June 4, 1991

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

Not Available

1991-01-01

This bill was introduced into the US House of Representatives on June 4, 1991 to regulate water quality degradation. Key features of this legislation addressed include the following: water quality standards and implementation plans; certification; state ocean dumping requirements; enforcement of certification provisions; and ocean discharge criteria.

Light reintroduction after dark exposure reactivates plasticity in adults via perisynaptic activation of MMP-9

PubMed Central

2017-01-01

The sensitivity of ocular dominance to regulation by monocular deprivation is the canonical model of plasticity confined to a critical period. However, we have previously shown that visual deprivation through dark exposure (DE) reactivates critical period plasticity in adults. Previous work assumed that the elimination of visual input was sufficient to enhance plasticity in the adult mouse visual cortex. In contrast, here we show that light reintroduction (LRx) after DE is responsible for the reactivation of plasticity. LRx triggers degradation of the ECM, which is blocked by pharmacological inhibition or genetic ablation of matrix metalloproteinase-9 (MMP-9). LRx induces an increase in MMP-9 activity that is perisynaptic and enriched at thalamo-cortical synapses. The reactivation of plasticity by LRx is absent in Mmp9−/− mice, and is rescued by hyaluronidase, an enzyme that degrades core ECM components. Thus, the LRx-induced increase in MMP-9 removes constraints on structural and functional plasticity in the mature cortex. PMID:28875930

The gypsophyte Gypsophila struthium as nurse plant for vegetation recovery in degraded gypsum substrates

NASA Astrophysics Data System (ADS)

María Foronda, Ana; Pueyo, Yolanda; Castillejo, José Miguel; Alados, Conceción L.

2017-04-01

Degraded areas such as quarries or dumps are devoid of vegetation where the spontaneous vegetation recovery is a very slow process that requires restoration actions, especially under harsh environmental conditions such as arid conditions and special substrates. Specifically, gypsum substrates have physical and chemical limitations such as surface crusts, poor water availability or high concentrations of SO4 and Ca. Some plants, the so called gypsophytes, are adapted to tolerate such limitations and thus, might be able to establish in gypsum bare soils. Thus, well adapted gypsophytes might play an important role in vegetation recovery by acting as ecosystem engineers, improving the environmental conditions under their canopy and facilitating the establishment of other species. Facilitation is being recently considered as a key process in restoration practices because it might enhance restoration effectiveness by favoring the plant establishment and therefore, plant succession. The aim of this study was to test the effectiveness of a gypsophyte (Gypsophila struthium) in facilitating the establishment and development of other species and thus in vegetation recovery of degraded gypsum substrates. To address this objective, a sowing and planting experiment was set in November 2014 in a gypsum dump located in Andorra municipality (Teruel, NE Spain). Forty well-established adults of G. struthium previously planted in that dump were employed as nurse plants in the experiment. Two species were used as test species in the experiment: Helianthemum squamatum (gypsophyte) and Stipa lagascae (non-gypsophyte). Seeds and seedlings of those test species were sowed and planted in two different microsites: under the canopy and in the surrounding bare soil of each G. struthium individual (n=80 per test species). Germination, survival and growth of test species were surveyed twice a year during two years. Soil compaction and soil temperature were seasonally measured at both microsites during two years to test the role of G. struthium plants as ecosystem engineers by changing abiotic conditions under their canopy. Preliminary results showed that planted seedlings of H. squamatum grew in volume and seedlings of S.lagascae grew in height significantly more under the canopy of G. struthium than in bare soil, while germination and survival rates were similar at both microsites. Additionally, abiotic data showed that soil compaction decreased and extreme temperatures were softened under the canopy of G. struthium plants. Our study suggests that G. struthium can play an important role in restoration effectiveness of areas degraded by quarrying because it improves micro-environmental conditions under its canopy, favoring the development of other species in gypsum substrates.

Anaerobic Metabolism and Bioremediation of Explosives-Contaminated Soil

NASA Astrophysics Data System (ADS)

Boopathy, Raj

Nitroaromatic compounds pollute soil, water, and food via use of pesticides, plastics, pharmaceuticals, landfill dumping of industrial wastes, and the military use of explosives. Biotransformation of trinitrotoluene and other nitroaromatics by aerobic bacteria in the laboratory has been frequently reported, but the anaerobic bacterial metabolism of nitroaromatics has not been studied as extensively perhaps due to the difficulty in working with anaerobic cultures and the slow growth of anaerobes. Sulfate-reducing and methanogenic bacteria can metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment.

Experimental degradation of polymer shopping bags (standard and degradable plastic, and biodegradable) in the gastrointestinal fluids of sea turtles.

PubMed

Müller, Christin; Townsend, Kathy; Matschullat, Jörg

2012-02-01

The persistence of marine debris such as discarded polymer bags has become globally an increasing hazard to marine life. To date, over 177 marine species have been recorded to ingest man-made polymers that cause life-threatening complications such as gut impaction and perforation. This study set out to test the decay characteristics of three common types of shopping bag polymers in sea turtle gastrointestinal fluids (GIF): standard and degradable plastic, and biodegradable. Fluids were obtained from the stomachs, small intestines and large intestines of a freshly dead Green turtle (Chelonia mydas) and a Loggerhead turtle (Caretta caretta). Controls were carried out with salt and freshwater. The degradation rate was measured over 49 days, based on mass loss. Degradation rates of the standard and the degradable plastic bags after 49 days across all treatments and controls were negligible. The biodegradable bags showed mass losses between 3 and 9%. This was a much slower rate than reported by the manufacturers in an industrial composting situation (100% in 49 days). The GIF of the herbivorous Green turtle showed an increased capacity to break down the biodegradable polymer relative to the carnivorous Loggerhead, but at a much lower rate than digestion of natural vegetative matter. While the breakdown rate of biodegradable polymers in the intestinal fluids of sea turtles is greater than standard and degradable plastics, it is proposed that this is not rapid enough to prevent morbidity. Further study is recommended to investigate the speed at which biodegradable polymers decompose outside of industrial composting situations, and their durability in marine and freshwater systems. Copyright © 2011 Elsevier B.V. All rights reserved.

Fate and effects of 2,4,6-trinitrotoluene (TNT) from dumped ammunition in a field study with fish and invertebrates.

PubMed

Ek, Helene; Dave, Göran; Nilsson, Eva; Sturve, Joachim; Birgersson, Göran

2006-08-01

2,4,6-Trinitrotoluene (TNT) is the major explosive ingredient in ammunition dumped into lakes and sea after World War II. The aim of the present field study was to study the fate and effect of TNT and its degradation products from dumped ammunition. Artillery shells were cleaved longitudinally to expose TNT and placed in open boxes filled with sediment, and then placed at the sea bottom. Sediment samples were taken in each box at the start and after 3, 9, 13, 20, 24, 33, and 36 months, and the sediments were tested for toxicity with bioassays using Nitocra spinipes (96 h), Hyalella azteca (96 h), and Daphnia magna (24 and 48 h). The result from the bioassays showed no impact of dumped ammunition on the survival of H. azteca and mobility of D. magna. Bioassays with N. spinipes showed significant differences in toxicity between control boxes and boxes with shells after 9 months and thereafter. The mean mortality (+/- SD) of N. spinipes in boxes with shells was 63 +/- 22%, and the mortality in control boxes was 23 +/- 17%. No continuous increase in sediment toxicity over time was found. After 3 years, cages with European flounder (Platichtys flesus) and blue mussels (Mytilus edulis) were attached to the boxes. The fish were examined for biochemical and physiological effects 8 weeks later. Exposure to ammunition, which had rested on the sea bottom 3 years, caused no significant effects on body indices, hematological variables, and detoxification and antioxidant enzymes activities in the flounder. The sediment, bile, and blood plasma of exposed fish, and hepatopancreas of exposed mussels, contained no detectable levels of TNT and its metabolites. Only minor disappearance of TNT from the shells could be detected by visual inspection on site (by scuba divers). This study suggests that the survival of sensitive benthic organisms, e.g., N. spinipes, might be negatively affected at an ammunition dumping site.

Biological degradation of wood-plastic composites (WPC) and strategies for improving the resistance of WPC against biological decay

Treesearch

Anke Schirp; Rebecca E. Ibach; David E. Pendleton; Michael P. Wolcott

2008-01-01

Much of the research on wood-plastic composites (WPC) has focused on formulation development and processing while high biological durability of the material was assumed. The gap between assumption and knowledge in biodeterioration of WPC needs to be reduced. Although some information on the short-term resistance of WPC against biological degradation is available, long-...

Osteoporosis affects both post-yield microdamage accumulation and plasticity degradation in vertebra of ovariectomized rats

NASA Astrophysics Data System (ADS)

Li, Siwei; Niu, Guodong; Dong, Neil X.; Wang, Xiaodu; Liu, Zhongjun; Song, Chunli; Leng, Huijie

2017-04-01

Estrogen withdrawal in postmenopausal women increases bone loss and bone fragility in the vertebra. Bone loss with osteoporosis not only reduces bone mineral density (BMD), but actually alters bone quality, which can be comprehensively represented by bone post-yield behaviors. This study aimed to provide some information as to how osteoporosis induced by estrogen depletion could influence the evolution of post-yield microdamage accumulation and plastic deformation in vertebral bodies. This study also tried to reveal the part of the mechanisms of how estrogen deficiency-induced osteoporosis would increase the bone fracture risk. A rat bilateral ovariectomy (OVX) model was used to induce osteoporosis. Progressive cyclic compression loading was developed for vertebra testing to elucidate the post-yield behaviors. BMD, bone volume fraction, stiffness degradation, and plastic deformation evolution were compared among rats raised for 5 weeks (ovx5w and sham5w groups) and 35 weeks (ovx35w and sham35w groups) after sham surgery and OVX. The results showed that a higher bone loss in vertebral bodies corresponded to lower stiffness and higher plastic deformation. Thus, osteoporosis could increase the vertebral fracture risk probably through microdamage accumulation and plastic deforming degradation.

Environmental performance of bio-based and biodegradable plastics: the road ahead.

PubMed

Lambert, Scott; Wagner, Martin

2017-11-13

Future plastic materials will be very different from those that are used today. The increasing importance of sustainability promotes the development of bio-based and biodegradable polymers, sometimes misleadingly referred to as 'bioplastics'. Because both terms imply "green" sources and "clean" removal, this paper aims at critically discussing the sometimes-conflicting terminology as well as renewable sources with a special focus on the degradation of these polymers in natural environments. With regard to the former we review innovations in feedstock development (e.g. microalgae and food wastes). In terms of the latter, we highlight the effects that polymer structure, additives, and environmental variables have on plastic biodegradability. We argue that the 'biodegradable' end-product does not necessarily degrade once emitted to the environment because chemical additives used to make them fit for purpose will increase the longevity. In the future, this trend may continue as the plastics industry also is expected to be a major user of nanocomposites. Overall, there is a need to assess the performance of polymer innovations in terms of their biodegradability especially under realistic waste management and environmental conditions, to avoid the unwanted release of plastic degradation products in receiving environments.

Effect of coal filler on the properties of soy protein plastics

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

Wang, G.H.; Zhou, A.N.; Hu, M.B.

2006-11-15

The influence of ultrafine coal filler (UFC) content on tensile properties, water absorption, and biodegradability of soy protein plastics were investigated. The addition of UFC in the soy protein plastics, with different content of glycerol as a plasticizer, was at different ratio varying from 10:0 to 6:4. Blend sheets of the soy protein composites were prepared by the compression molding processing. The results show that, with 23.08 wt % glycerol, the tensile strength and elongation at break for the soy protein sheet with coal filler (range from 5 to 30 parts) can be enhanced as compared with nonfilled soy proteinmore » plastics. Water resistance of the soy protein plastics improves with the increase in UFC content. The derivative thermogravimetry (DTG) curves indicate a double-stage degradation process for defatted soy flour (SPF), while three-stage degradation process for soy plastics and the soy protein composites. FT-IR, XPS, and SEM were applied to study the interfacial interaction between coal macromolecules and soy protein molecules in UFC filled soy protein plastics. The results demonstrated that there is strong interfacial interaction in the soy protein plastics caused by the compression molding processing.« less

Electromagnetic bonding of plastics to aluminum

NASA Technical Reports Server (NTRS)

Sheppard, A. T.; Silbert, L.

1980-01-01

Electromagnetic curing is used to bond strain gage to aluminum tensile bar. Electromagnetic energy heats only plastic/metal interface by means of skin effect, preventing degradation of heat-treated aluminum. Process can be easily applied to other metals joined by high-temperature-curing plastic adhesives.

The existence of microplastic in Asian green mussels

NASA Astrophysics Data System (ADS)

Khoironi, A.; Anggoro, S.; Sudarno

2018-03-01

Due to resistance of polymer as basic properties of plastic, several studies have been conducted to understand the fate of plastic debris in the marine environment. Degradation is the most important process to control distribution of plastic debris a long the marine environment until the existence of plastic in the food chain. The physical and chemical changes of plastic because of degradation process will lead to the release of polluted substances which eventually more toxic for the environment. Furthermore, when plastic degraded become a microplastic will lead to easy ingested by biotic such as mussell which commonly consumed by humans. The aim of this research was to investigate the concentration of microplastic adsorbed and ingested by mussels considering characteristic of sea water. About 30 samples have been collected from 3 different locations that is brackish water (31 ppb), high salinity (36 ppb) and low salinity (33 ppb) for measuring a number of microplastic in mussels on three different salinity. The result of microstructure analysis by microscope showed that mussel evaluated from the marine environment contaminated by microplastic with average size of 211.163 μm. In high salinity sea water, microplastic found in mussel was greater than low salinity and brackish water. The SEM/EDX analysis showed the presence of SIO2 0.14 % (w/w), Na2O 24.27 %(w/w) and Al2O3 0.27 % (w/w) in the microplastic obtained in the mussel indicating the components which are mostly found in the plastic industries. The amount of microplastic in mussell could be used as pollution indicator in the marine environmental by plastic waste.

Rhizosphere of Avicennia marina (Forsk.) Vierh. as a landmark for polythene degrading bacteria.

PubMed

Shahnawaz, Mohd; Sangale, Manisha K; Ade, Avinash B

2016-07-01

Due to high durability, cheap cost, and ease of manufacture, 311 million tons of plastic-based products are manufactured around the globe per annum. The slow/least rate of plastic degradation leads to generation of million tons of plastic waste per annum, which is of great environmental concern. Of the total plastic waste generated, polythene shared about 64 %. Various methods are available in the literature to tackle with the plastic waste, and biodegradation is considered as the most accepted, eco-friendly, and cost-effective method of polythene waste disposal. In the present study, an attempt has been made to isolate, screen, and characterize the most efficient polythene degrading bacteria by using rhizosphere soil of Avicennia marina as a landmark. From 12 localities along the west coast of India, a total of 123 bacterial isolates were recorded. Maximum percent weight loss (% WL; 21.87 ± 6.37 %) was recorded with VASB14 at pH 3.5 after 2 months of shaking at room temperature. Maximum percent weight gain (13.87 ± 3.6 %) was reported with MANGB5 at pH 7. Maximum percent loss in tensile strength (% loss in TS; 87.50 ± 4.8 %) was documented with VASB1 at pH 9.5. The results based on the % loss in TS were only reproducible. Further, the level of degradation was confirmed by scanning electron microscopic (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis. In SEM analysis, scions/crakes were found on the surface of the degraded polythene, and mass of bacterial cell was also recorded on the weight-gained polythene strips. Maximum reduction in carbonyl index (4.14 %) was recorded in untreated polythene strip with Lysinibacillus fusiformis strain VASB14/WL. Based on 16S ribosomal RNA (rRNA) gene sequence homology, the most efficient polythene degrading bacteria were identified as L. fusiformis strainVASB14/WL and Bacillus cereus strain VASB1/TS.

Excitons and the lifetime of organic semiconductor devices.

PubMed

Forrest, Stephen R

2015-06-28

While excitons are responsible for the many beneficial optical properties of organic semiconductors, their non-radiative recombination within the material can result in material degradation due to the dumping of energy onto localized molecular bonds. This presents a challenge in developing strategies to exploit the benefits of excitons without negatively impacting the device operational stability. Here, we will briefly review the fundamental mechanisms leading to excitonic energy-driven device ageing in two example devices: blue emitting electrophosphorescent organic light emitting devices (PHOLEDs) and organic photovoltaic (OPV) cells. We describe strategies used to minimize or even eliminate this fundamental device degradation pathway. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

What Happens to Bio-degradables in the Ocean? Due to the increasing amount of plastic that ends up in the ocean there is much alarm about it killing sea life from ingestion and changing chemical properties of the ocean. But what really happens t these products in the ocean, and how do they affect the ocean.

NASA Astrophysics Data System (ADS)

Lavoie, A.

2016-12-01

What Happens to Bio-degradables in the Ocean? Due to the increasing amount of plastic that ends up in the ocean there is much alarm about it killing sea life from entanglement and ingestion and changing chemical properties of the ocean. Our society is trying to take action by purchasing and using materials that claim to be biodegradable. But how long do these materials take to degrade in ocean water and do they actually change the water composition? Answering these questions will determine if one should invest in these materials as an alternative to plastic.

Correlating elastic and plastic deformation with magnetic permeability values

NASA Astrophysics Data System (ADS)

Papadopoulou, S.

2017-12-01

This paper investigates the utilization of magnetic permeability method in determining elastic and plastic deformation state of ferromagnetic steels. The results have shown a strong degradation of the magnetic values on plastically region due to the irreversible movements of the magnetic domain walls.

Biodegradable and bio-based polymers: future prospects of eco-friendly plastics.

PubMed

Iwata, Tadahisa

2015-03-09

Currently used plastics are mostly produced from petrochemical products, but there is a growing demand for eco-friendly plastics. The use of bio-based plastics, which are produced from renewable resources, and biodegradable plastics, which are degraded in the environment, will lead to a more sustainable society and help us solve global environmental and waste management problems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microbial enzymes for the recycling of recalcitrant petroleum-based plastics: how far are we?

PubMed

Wei, Ren; Zimmermann, Wolfgang

2017-11-01

Petroleum-based plastics have replaced many natural materials in their former applications. With their excellent properties, they have found widespread uses in almost every area of human life. However, the high recalcitrance of many synthetic plastics results in their long persistence in the environment, and the growing amount of plastic waste ending up in landfills and in the oceans has become a global concern. In recent years, a number of microbial enzymes capable of modifying or degrading recalcitrant synthetic polymers have been identified. They are emerging as candidates for the development of biocatalytic plastic recycling processes, by which valuable raw materials can be recovered in an environmentally sustainable way. This review is focused on microbial biocatalysts involved in the degradation of the synthetic plastics polyethylene, polystyrene, polyurethane and polyethylene terephthalate (PET). Recent progress in the application of polyester hydrolases for the recovery of PET building blocks and challenges for the application of these enzymes in alternative plastic waste recycling processes will be discussed. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Plastic degrading fungi Trichoderma viride and Aspergillus nomius isolated from local landfill soil in Medan

NASA Astrophysics Data System (ADS)

Munir, E.; Harefa, R. S. M.; Priyani, N.; Suryanto, D.

2018-03-01

Plastic is a naturally recalcitrant polymer, once it enters the environment, it will remain there for many years. Accumulation of plastic as wastes in the environment poses a serious problem and causes an ecological threat. Alternative strategies to reduce accumulation of plastic wastes have been initiated and implemented from a different aspect including from microbiological view point. The study to obtain potential fungi in degrading plastic molecule has been initiated in our laboratory. Low density polyethylene (LDPE) plastic was used as a tested material. Candidate fungi were isolated from local landfill soil. The fungi were cultured in mineral salt medium broth containing LDPE powder. Two of nine isolates showed best growth response in broth media containing LDPE. These isolates (RH03 and RH06) were used in degradation test. Results showed that isolate RH03 and RH06 reduced the weight of LDPE film by 5.13% and 6.63%, respectively after 45 days of cultivation. The tensile strength of treated film even reduced significantly by 58% and 40% of each isolate. Analyses of electron micrograph exhibited grove ands rough were formed on the surface of LDPE film. These were not found in the untreated film. Furthermore, molecular analysis through polymerase chain reaction and DNA sequencing indicated that RH03 is Trichoderma viride and RH06 is Aspergillus nomius with 97% and 96% similarities, respectively.

Evaluation of Pad 18 Spent Mercury Gold Trap Stainless Steel Container Failure

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

Skidmore, E.

Failure of the Pad 18 spent mercury gold trap stainless steel waste container is principally attributed to corrosion induced by degradation of plasticized polyvinyl chloride (pPVC) waste packaging material. Dehydrochlorination of pPVC polymer by thermal and/or radiolytic degradation is well-known to evolve HCl gas, which is highly corrosive to stainless steel and other metals in the presence of moisture. Degradation of the pPVC packaging material was likely caused by radiolysis in the presence of tritium gas within the waste container, though other degradation mechanisms (aging, thermo-oxidation, plasticizer migration) over 30 years storage may have contributed. Corrosion was also likely enhancedmore » by the crevice in the container weld design, and may have been enhanced by the presence of tritiated water. Similar non-failed spent mercury gold trap waste containers did not show radiographic evidence of plastic packaging or trapped free liquid within the container. Therefore, those containers are not expected to exhibit similar failures. Halogenated polymers such as pPVC subject to degradation can evolve halide gases such as HCl, which is corrosive in the presence of moisture and can generate pressure in sealed systems.« less

Geochemical investigations and interim recommendations for priority abandoned mine sites on U.S.D.A. Forest Service lands, Mineral Creek watershed, San Juan County, Colorado

USGS Publications Warehouse

Nash, J.T.

1999-01-01

Field observations, sampling of mine dumps and mine drainage waters, and laboratory studies of dump materials have been made at mining areas deemed to be on public lands administered by the USDA Forest Service in the Mineral Creek watershed. Results of chemical analyses of dump materials, leachates of those materials, and of surface waters draining mines or dumps provide indications of where acid is generated or consumed, and what metals are mobilized below mines or dumps. Information on 25 sites is reviewed and reclamation priorities are ranked into four classes (high, medium, low priority, or no work required). The western side of the upper Animas watershed (the Mineral Creek watershed) has a history of mining and prospecting for about 130 years. The intensity of miningrelated disturbance is higher than in most parts of the San Juan Mountains region, but actually is much less than the eastern half of the watershed (US BLM lands) and none of the mines moved millions of tons of rock and ore as in some of the eastern mines. The majority of the roughly one thousand mining sites on the USFS lands are very small (less than 100 tons or 70 cubic yards of dump material), are more than 2 miles from a major stream, or are so inaccessible as to prohibit reclamation. Twenty five sites have been considered by others to have significant size and potential for significant environmental degradation. These most significant mining areas were evaluated by multiple criteria, including tendency to generate acid or liberate toxic metals, observed acidic pH or dead vegetation (?kill zones?) below dumps or adits, potential mobility of metals, and likelihood of transport into streams of the watershed. In the author?s opinion, no single measurable parameter, such as metal concentration, is reliable for ranking significance or feasibility of reclamation. Rather, subjective estimates are required to evaluate combinations of, or interactions among, several parameters. The most subjective estimate in ranking feasibility of reclamation is the amount of natural and mine-related contamination at each mining area. Mitigation of natural contributions at mines or unmined areas is beyond the scope of these Abandoned Mine Lands (AML) investigations, but must be considered when planning reclamation. Available information for the 25 problem sites is adequate for ranking, but at some sites additional information on groundwater conditions is needed for a more reliable ranking and evaluation of reclamation methods.

Urban waste landfill planning and karstic groundwater resources in developing countries: the example of Lusaka (Zambia)

NASA Astrophysics Data System (ADS)

De Waele, J.; Nyambe, I. A.; Di Gregorio, A.; Di Gregorio, F.; Simasiku, S.; Follesa, R.; Nkemba, S.

2004-06-01

Lusaka, the capital city of Zambia with more than two million inhabitants, derives approximately 70% of its water requirements from groundwater sourced in the underlying karstic Lusaka aquifer. This water resource is, therefore, extremely important for the future of the population. The characteristics of the aquifer and the shallow water table make the resource vulnerable and in need of protection and monitoring. A joint project between the Geology Departments of the University of Cagliari and the School of Mines of the University of Zambia, to investigate the "Anthropogenic and natural processes in the Lusaka area leading to environmental degradation and their possible mitigation" was carried out in July 2001. The main objective of the study was to evaluate the extent of the present environmental degradation, assessing the vulnerability of the carbonatic aquifer and the degree of pollution of the groundwater and to make proposals to mitigate adverse environmental effects. Analyses of water samples collected during project indicate some areas of concern, particularly with respect to the levels of ammonia, nitrates and some heavy metals. As groundwater quality and quantity are prerogatives for a healthy and sustainable society, the study offers guidelines for consideration by the local and national authorities. Uptake of these guidelines should result in a number of initiatives being taken, including: (a) closure or reclamation of existing waste dumps; (b) upgrading of existing waste dumps to controlled landfills; (c) establishing new urban waste landfills and plants in geo-environmentally suitable sites; (d) local waste management projects in all compounds (residential areas) to prevent and reduce haphazard waste dumping; (e) enlarging sewerage drainage systems to all compounds; (f) enforcing control on groundwater abstraction and pollution, and demarcation of zones of control at existing drill holes; (g) providing the city with new water supplies from outside the Lusaka well-field; and (h) in increasing environmental education in schools and to all citizens.

Rock Failure Analysis Based on a Coupled Elastoplastic-Logarithmic Damage Model

NASA Astrophysics Data System (ADS)

Abdia, M.; Molladavoodi, H.; Salarirad, H.

2017-12-01

The rock materials surrounding the underground excavations typically demonstrate nonlinear mechanical response and irreversible behavior in particular under high in-situ stress states. The dominant causes of irreversible behavior are plastic flow and damage process. The plastic flow is controlled by the presence of local shear stresses which cause the frictional sliding. During this process, the net number of bonds remains unchanged practically. The overall macroscopic consequence of plastic flow is that the elastic properties (e.g. the stiffness of the material) are insensitive to this type of irreversible change. The main cause of irreversible changes in quasi-brittle materials such as rock is the damage process occurring within the material. From a microscopic viewpoint, damage initiates with the nucleation and growth of microcracks. When the microcracks length reaches a critical value, the coalescence of them occurs and finally, the localized meso-cracks appear. The macroscopic and phenomenological consequence of damage process is stiffness degradation, dilatation and softening response. In this paper, a coupled elastoplastic-logarithmic damage model was used to simulate the irreversible deformations and stiffness degradation of rock materials under loading. In this model, damage evolution & plastic flow rules were formulated in the framework of irreversible thermodynamics principles. To take into account the stiffness degradation and softening on post-peak region, logarithmic damage variable was implemented. Also, a plastic model with Drucker-Prager yield function was used to model plastic strains. Then, an algorithm was proposed to calculate the numerical steps based on the proposed coupled plastic and damage constitutive model. The developed model has been programmed in VC++ environment. Then, it was used as a separate and new constitutive model in DEM code (UDEC). Finally, the experimental Oolitic limestone rock behavior was simulated based on the developed model. The irreversible strains, softening and stiffness degradation were reproduced in the numerical results. Furthermore, the confinement pressure dependency of rock behavior was simulated in according to experimental observations.

Microbial degradation of low-density polyethylene (LDPE) by Aspergillus clavatus strain JASK1 isolated from landfill soil.

PubMed

Gajendiran, Anudurga; Krishnamoorthy, Sharmila; Abraham, Jayanthi

2016-06-01

Polythene and plastic waste are found to accumulate in the environment, posing a major ecological threat. They are found to be considered non-degradable, once it enters the environment it has been found to remain there indefinitely. However, significant attention has been placed on biodegradable polymer, identification of microbes with degradative potential on plastic material. The aim of the present investigation was to biodegrade low-density polyethylene (LDPE) using potential fungi isolated from landfill soil. Based on 18S rRNA analyses the isolated strain was identified as Aspergillus clavatus. LDPE degradation by A. clavatus was monitored for 90 days of incubation in aqueous medium. The degradation was confirmed by changes in polyethylene weight, CO 2 evolution by Strum test, infrared spectra and morphological changes by SEM and AFM analysis.

Degradation of brominated flame retardant in computer housing plastic by supercritical fluids.

PubMed

Wang, Yanmin; Zhang, Fu-Shen

2012-02-29

The degradation process of brominated flame retardant (BFR) and BFR-containing waste computer housing plastic in various supercritical fluids (water, methanol, isopropanol and acetone) was investigated. The results showed that the debromination and degradation efficiencies, final products were greatly affected by the solvent type. Among the four tested solvents, isopropanol was the most suitable solvent for the recovery of oil from BFR-containing plastic for its (1) excellent debromination effectiveness (debromination efficiency 95.7%), (2) high oil production (60.0%) and (3) mild temperature and pressure requirements. However, in this case, the removed bromine mostly existed in the oil. Introduction of KOH into the sc-isopropanol could capture almost all the inorganic bromine from the oil thus bromine-free oil could be obtained. Furthermore, KOH could enhance the depolymerization of the plastic. The obtained oil mainly consisted of single- and duplicate-ringed aromatic compounds in a carbon range of C9-C17, which had alkyl substituents or aliphatic bridges, such as butyl-benzene, (3-methylbutyl)-benzene, 1,1'-(1,3-propanediyl)bis benzene. Phenol, alkyl phenols and esters were the major oxygen-containing compounds in the oil. This study provides an efficient approach for debromination and simultaneous recovering valuable chemicals from BFR-containing plastic in e-waste. Copyright © 2011 Elsevier B.V. All rights reserved.

Waste dumps in local communities in developing countries and hidden danger to health.

PubMed

Anetor, Gloria O

2016-07-01

The rapid industrialisation and urbanisation fuelled by a fast-growing population has led to the generation of a huge amount of waste in most communities in developing countries. The hidden disorders and health dangers in waste dumps are often ignored. The waste generated in local communities is usually of a mixed type consisting of domestic waste and waste from small-scale industrial activities. Among these wastes are toxic metals, lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), halogenated organic compounds, plastics, remnants of paints that are themselves mixtures of hazardous substances, hydrocarbons and petroleum product-contaminated devices. Therefore, there is the urgent need to create an awareness of the harmful health effect of toxic wastes in developing countries, especially Nigeria. This is a review aimed at creating awareness on the hidden dangers of waste dumps to health in local communities in developing countries. Many publications in standard outlets use the following keywords: cancer, chemical toxicity, modern environmental health hazards, waste management and waste speciation in PubMed, ISI, Toxbase environmental digest, related base journals, and some standard textbooks, as well as the observation of the researcher between 1959 and 2014. Studies revealed the preponderance of toxic chemicals such as Pb, Cd, As and Hg in dump sites that have the risk of entering food chain and groundwater supplies, and these can give rise to endemic malnutrition and may also increase susceptibility to mutagenic substances, thereby increasing the incidence of cancer in developing countries. Industrialisation and urbanisation have brought about a change in the waste that is generated in contemporary communities in developing countries. Therefore, there is the need to embrace speciation and sound management of waste, probably including bioremediation. The populations in the local communities need regulatory agencies who are health educators as positive change agents. © Royal Society for Public Health 2016.

Development of the HS-SPME-GC-MS/MS method for analysis of chemical warfare agent and their degradation products in environmental samples.

PubMed

Nawała, Jakub; Czupryński, Krzysztof; Popiel, Stanisław; Dziedzic, Daniel; Bełdowski, Jacek

2016-08-24

After World War II approximately 50,000 tons of chemical weapons were dumped in the Baltic Sea by the Soviet Union under the provisions of the Potsdam Conference on Disarmament. These dumped chemical warfare agents still possess a major threat to the marine environment and to human life. Therefore, continue monitoring of these munitions is essential. In this work, we present the application of new solid phase microextraction fibers in analysis of chemical warfare agents and their degradation products. It can be concluded that the best fiber for analysis of sulfur mustard and its degradation products is butyl acrylate (BA), whereas for analysis of organoarsenic compounds and chloroacetophenone, the best fiber is a co-polymer of methyl acrylate and methyl methacrylate (MA/MMA). In order to achieve the lowest LOD and LOQ the samples should be divided into two subsamples. One of them should be analyzed using a BA fiber, and the second one using a MA/MMA fiber. When the fast analysis is required, the microextraction should be performed by use of a butyl acrylate fiber because the extraction efficiency of organoarsenic compounds for this fiber is acceptable. Next, we have elaborated of the HS-SPME-GC-MS/MS method for analysis of CWA degradation products in environmental samples using laboratory obtained fibers The analytical method for analysis of organosulfur and organoarsenic compounds was optimized and validated. The LOD's for all target chemicals were between 0.03 and 0.65 ppb. Then, the analytical method developed by us, was used for the analysis of sediment and pore water samples from the Baltic Sea. During these studies, 80 samples were analyzed. It was found that 25 sediments and 5 pore water samples contained CWA degradation products such as 1,4-dithiane, 1,4-oxathiane or triphenylarsine, the latter being a component of arsine oil. The obtained data is evidence that the CWAs present in the Baltic Sea have leaked into the general marine environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Environmental Impact Assessment of Rosia Jiu Opencast Area Using AN Integrated SAR Analysis

NASA Astrophysics Data System (ADS)

Poenaru, V. D.; Negula, I. F. Dana; Badea, A.; Cuculici, R.

2016-06-01

The satellite data provide a new perspective to analyse and interpret environmental impact assessment as function of topography and vegetation. The main goal of this paper is to investigate the new Staring Spotlight TerraSAR-X mode capabilities to monitor land degradation in Rosia Jiu opencast area taking into account the mining engineering standards and specifications. The second goal is to relate mining activities with spatio-temporal dynamics of land degradation by using differential Synthetic Aperture Radar interferometry (DInSAR). The experimental analysis was carried out on data acquired in the LAN_2277 scientific proposal framework during 2014-2015 period. A set of 25 very height resolution SAR data gathered in the VV polarisation mode with a resolution of 0.45 m x 0.16m and an incidence angle of 37° have been used in this study. Preliminary results showed that altered terrain topography with steep slopes and deep pits has led to the layover of radar signal. Initially, ambiguous results have been obtained due to the highly dynamic character of subsidence induced by activities which imply mass mining methods. By increasing the SAR data number, the land degradation assessment has been improved. Most of the interferometric pairs have low coherence therefore the product coherence threshold was set to 0.3. A coherent and non-coherent analysis is performed to delineate land cover changes and complement the deformation model. Thus, the environmental impact of mining activities is better studied. Moreover, the monitoring of changes in pit depths, heights of stock-piles and waste dumps and levels of tailing dumps provide additional information about production data.

Stability of Glass Fiber-Plastic Composites

DTIC Science & Technology

1974-11-01

miniiiii’ 5 0712 01016774 9 x TECHNICA. . LIBRARY Jt U*Al>/l 1 Technical Report RL-75-6 STABILITY OF GLASS FIBER -PLASTIC COMPOSITES Wartan A...Subtitle) STABILITY OF GLASS FIBER -PLASTIC COMPOSITES 5. TYPE OF REPORT & PERIOD COVERED Technical Report 6. PERFORMING ORG. REPORT NUMBER 7...Exploratory research was conducted to determine the stages and nature of degradation of glass fiber -plastic composite systems under various environmental

Enhanced biodegradation of low and high-density polyethylene by novel bacterial consortia formulated from plastic-contaminated cow dung under thermophilic conditions.

PubMed

Skariyachan, Sinosh; Setlur, Anagha Shamsundar; Naik, Sujay Yashwant; Naik, Ashwini Amaresh; Usharani, Makam; Vasist, Kiran S

2017-03-01

The current study aimed to devise eco-friendly, safe, and cost-effective strategies for enhanced degradation of low- and high-density polyethylene (LDPE and HDPE) using newly formulated thermophilic microbial consortia from cow dung and to assess the biodegradation end products. The plastic-degrading bacteria from cow dung samples gathered from highly plastic-acclimated environments were enriched by standard protocols. The degradation ability was comprehended by zone of clearance method, and the percentage of degradation was monitored by weight reduction process. The best isolates were characterized by standard microbiological and molecular biology protocols. The best isolates were employed to form several combinations of microbial consortia, and the degradation end products were analyzed. The stability of 16S ribosomal DNA (rDNA) was predicted by bioinformatics approach. This study identified 75 ± 2, 55 ± 2, 60 ± 3, and 43 ± 3% degradation for LDPE strips, pellets, HDPE strips, and pellets, respectively, for a period of 120 days (p < 0.05) at 55 °C by the formulated consortia of IS1-IS4, and the degradation efficiency was found to be better in comparison with other formulations. The end product analysis by Fourier transform infrared, scanning electron microscopy, energy-dispersive spectroscopy, and nuclear magnetic resonance showed major structural changes and formation of bacterial biofilm on plastic surfaces. These novel isolates were designated as Bacillus vallismortis bt-dsce01, Psuedomonas protegens bt-dsce02, Stenotrophomonas sp. bt-dsce03, and Paenibacillus sp.bt-dsce04 by 16S rDNA sequencing and suggested good gene stability with minimum Gibb's free energy. Therefore, this study imparts substantial information regarding the utilization of these thermophilic microbial consortia from cow dung for rapid polyethylene removal.

Methacrylate based cross-linkers for improved thermomechanical properties and retention of radiation detection response in plastic scintillators

NASA Astrophysics Data System (ADS)

Mahl, Adam; Lim, Allison; Latta, Joseph; Yemam, Henok A.; Greife, Uwe; Sellinger, Alan

2018-03-01

Pulse shape discrimination (PSD) is an important method that can efficiently sort and separate neutron and gamma radiation signals. PSD is currently achieved in plastic scintillators by over-doping poly(vinyl toluene) (PVT) matrices with fluorescent molecules. Meaningful separation of the signals requires addition of >20 wt% 2,5-diphenyloxazole (PPO) fluor in PVT. At these concentrations PPO acts as a plasticizer, negatively affecting the physical properties of the final plastic such as hardness, machinability, and thermomechanical stability. This work addresses these issues by implementing a cost-effective solution using cross-linking chemistry via commercially available bisphenol A dimethacrylate (BPA-DM), and a synthesized fluorinated analogue. Both improve the physical properties of over-doped PPO based plastic scintillators without degrading the measured light yield or PSD and Figure of Merit (FoM). In addition, the fluorinated analogue appears to enhance the hydrophobicity of the surface of the plastic scintillators, which may improve the scintillators' resistance to water diffusion and subsequent radiation response degradation. The new formulations improve the feasibility of widely deploying long lifetime PSD capable plastic scintillators in large area coverage assemblies.

Life in the "plastisphere": microbial communities on plastic marine debris.

PubMed

Zettler, Erik R; Mincer, Tracy J; Amaral-Zettler, Linda A

2013-07-02

Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic marine debris (PMD) collected at multiple locations in the North Atlantic was analyzed with scanning electron microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere". Pits visualized in the PMD surface conformed to bacterial shapes suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit rRNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specific members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.

Evaluation of a chemical munition dumpsite in the Baltic Sea based on geophysical and chemical investigations.

PubMed

Missiaen, Tine; Söderström, Martin; Popescu, Irina; Vanninen, Paula

2010-08-01

This paper discusses the results of geophysical and chemical investigations carried out in a chemical munition dumpsite in the southern Baltic Sea, east of the island of Bornholm. After WW2 over 32,000 tons of chemical war material was dumped here including shells and bombs as well as small drums and containers. The geophysical investigations combined very-high-resolution seismics and gradiometric measurements. The results indicate the presence of a large number of objects buried just below the seafloor. The size of the objects and their distribution, with a marked increase in density towards the center of the dumpsite, suggests that we are dealing with dumped war material. Sediment and near-bottom water samples, taken within the dumpsite and in the surrounding area, were analysed for the presence of various chemical warfare agents (CWA) including Adamsite, Clark, sulphur mustard, tabun, chlorobenzene and arsine oil. The results indicate a widespread contamination that reaches far beyond the dumpsite boundary. CWA degradation products were found in most of the sediment samples. The contamination was mostly related to arsenic containing compounds; only one sample indicated the presence of sulfur mustard. Although the correlation between detected objects and CWA concentrations is not always straightforward, the overall results suggest that a lot of the dumped war material is leaking and that over the years the contamination has reached the seafloor sediments.

Structural insight into molecular mechanism of poly(ethylene terephthalate) degradation.

PubMed

Joo, Seongjoon; Cho, In Jin; Seo, Hogyun; Son, Hyeoncheol Francis; Sagong, Hye-Young; Shin, Tae Joo; Choi, So Young; Lee, Sang Yup; Kim, Kyung-Jin

2018-01-26

Plastics, including poly(ethylene terephthalate) (PET), possess many desirable characteristics and thus are widely used in daily life. However, non-biodegradability, once thought to be an advantage offered by plastics, is causing major environmental problem. Recently, a PET-degrading bacterium, Ideonella sakaiensis, was identified and suggested for possible use in degradation and/or recycling of PET. However, the molecular mechanism of PET degradation is not known. Here we report the crystal structure of I. sakaiensis PETase (IsPETase) at 1.5 Å resolution. IsPETase has a Ser-His-Asp catalytic triad at its active site and contains an optimal substrate binding site to accommodate four monohydroxyethyl terephthalate (MHET) moieties of PET. Based on structural and site-directed mutagenesis experiments, the detailed process of PET degradation into MHET, terephthalic acid, and ethylene glycol is suggested. Moreover, other PETase candidates potentially having high PET-degrading activities are suggested based on phylogenetic tree analysis of 69 PETase-like proteins.

Characterization of plastic beach debris finalized to its removal: a proposal for a recycling scheme.

PubMed

Pietrelli, Loris; Poeta, Gianluca; Battisti, Corrado; Sighicelli, Maria

2017-07-01

Characterization of beach debris is crucial to assess the strategy to answer questions such as recycling. With the aim to assess its use in a recycling scheme, in this note, we carried out a physical and chemical characterization of plastic litter from a pilot beach in Central Italy, using the FT-IR spectroscopy and thermoanalysis. Fourteen polymers, having mainly thermoplastic origin, were identified; among them, the most represented are polyethylene (41.7%) and polypropylene (36.9%). Chemical and mechanical degradation were clearly observed by an IR spectrum. The thermogravimetric analysis curve of the plastic blend shows the melting point at 120-140 °C, and degradation occurs almost totally in a one-step process within 300-500 °C. The high heating value of the plastic debris is 43.9 MJ kg -1 . Polymer blends obtained by beach debris show mechanical properties similar to the virgin high-density polyethylene polymer. Following the beach plastic debris characterization, a recycling scheme was suggested.

Compositions of volatile organic compounds emitted from melted virgin and waste plastic pellets.

PubMed

Yamashita, Kyoko; Yamamoto, Naomichi; Mizukoshi, Atsushi; Noguchi, Miyuki; Ni, Yueyong; Yanagisawa, Yukio

2009-03-01

To characterize potential air pollution issues related to recycling facilities of waste plastics, volatile organic compounds (VOCs) emitted from melted virgin and waste plastics pellets were analyzed. In this study, laboratory experiments were performed to melt virgin and waste plastic pellets under various temperatures (150, 200, and 250 degrees C) and atmospheres (air and nitrogen [N2]). In the study presented here, low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS) and the recycled waste plastic pellets were used. The VOCs generated from each plastic pellets were collected by Tenax/Carboxen adsorbent tubes and analyzed by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). The result showed the higher temperatures generated larger amounts of total VOCs (TVOCs). The VOCs emitted from the virgin plastic pellets likely originated from polymer degradation. Smaller TVOC emissions were observed in N2 atmosphere than in air atmosphere. In particular, larger amounts of the oxygenated compounds, which are generally hazardous and malodorous, were detected in air than in N2. In addition to the compounds originating from polymer degradation, the compounds originating from the plastic additives were also detected from LDPE and PS. Furthermore, various species of VOCs likely originating from contaminant inseparate polyvinyl chloride (PVC), food residues, cleaning agents, degreasers, and so on were detected from the waste plastic. Thus, melting waste plastics, as is conducted in recycling facilities, might generate larger amounts of potentially toxic compounds than producing virgin plastics.

Using magnetic levitation for non-destructive quality control of plastic parts.

PubMed

Hennek, Jonathan W; Nemiroski, Alex; Subramaniam, Anand Bala; Bwambok, David K; Yang, Dian; Harburg, Daniel V; Tricard, Simon; Ellerbee, Audrey K; Whitesides, George M

2015-03-04

Magnetic levitation (MagLev) enables rapid and non-destructive quality control of plastic parts. The feasibility of MagLev as a method to: i) rapidly assess injection-molded plastic parts for defects during process optimization, ii) monitor the degradation of plastics after exposure to harsh environmental conditions, and iii) detect counterfeit polymers by density is demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Formation of Neogenic Ores on the Dump-Heaps of Old Uranium Mines and on the Mine-Head of Mines under Exploitation; FORMATION DE MINERAUX NEOGENES SUR LES HALDES D'ANCIENNES MINES D'URANIUM ET SUR LE CARREAU DES MINES EN EXPLOITATION

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

Chervet, J.

1960-01-01

The major degradations suffered by primary and secondary uranium ores under the weathering action of air and water are assessed. Pyritic ores were found to be the most vunerable. The interactions between pynite oxidation products and urantferous compounds often lead to the formation of neogentc ores. (C.J.G.)

Thermal alterations of organic matter in coal wastes from Upper Silesia, Poland

NASA Astrophysics Data System (ADS)

Misz-Kennan, Magdalena

2010-01-01

Self-heating and self-combustion are currently taking place in some coal waste dumps in the Upper Silesian Coal Basin, Poland, e.g. the dumps at Rymer Cones, Starzykowiec, and the Marcel Coal Mine, all in the Rybnik area. These dumps are of similar age and self-heating and combustion have been occurring in all three for many years. The tools of organic petrography (maceral composition, rank, etc.), gas chromatography-mass spectrometry, and proximate and ultimate analysis are used to investigate the wastes. Organic matter occurs in quantities up to 85 vol.%, typically a few to several vol.%, in the wastes. All three maceral groups (vitrinite, liptinite, and inertinite) are present as unaltered and variously-altered constituents associated with newly-formed petrographic components (bitumen expulsions, pyrolytic carbon). The predominant maceral group is vitrinite with alterations reflected in the presence of irregular cracks, oxidation rims and, rarely, devolatilisation pores. In altered wastes, paler grey-vitrinite and/or coke dominates. The lack of plasticity, the presence of paler-coloured particles, isotropic massive coke, dispersed coked organic matter, and expulsions of bitumens all indicate that heating was slow and extended over a long time. Macerals belonging to other groups are present in unaltered form or with colours paler than the colours of the parent macerals. Based on the relative contents of organic compounds, the most important groups of these identified in the wastes are n-alkanes, acyclic isoprenoids, hopanes, polycyclic aromatic hydrocarbons (PAHs) and their derivatives, phenol and its derivatives. These compounds occur in all wastes except those most highly altered where they were probably destroyed by high temperatures. These compounds were generated mainly from liptinite-group macerals. Driven by evaporation and leaching, they migrated within and out of the dump. Their presence in some wastes in which microscopically visible organic matter is lacking suggests that they originated elsewhere and subsequently migrated through the dump piles. During their migration, the compounds fractionated, were adsorbed on minerals and/or interacted. The absence of alkenes, and of other unsaturated organic compounds, may reflect primary diagenetic processes that occurred in coals and coal shales during burial and/or organic matter type. Their absence may also be a consequence of heating that lasted many years, hydropyrolysis, and/or the participation of minerals in the reactions occurring within the dumps. The wastes contain compounds typical of organic matter of unaltered kerogen III type and the products of pyrolytic processes, and mixtures of both. In some wastes, organic compounds are completely absent having been destroyed by severe heating. The distributions of n-alkanes in many samples are typical of pyrolysates. In some wastes, narrow n-alkane distributions reflect their generation over small temperature ranges. In others, wider distributions point to greater temperature ranges. Other wastes contain n-alkane distributions typical of unaltered coal and high pristane content or mixtures of pyrolysates and unaltered waste material. The wastes also contain significant amounts of final αβ hopanes. Polycyclic aromatic hydrocarbons are represented only by two- to five-ring compounds as is typical of the thermal alteration of hard coal. Correlations between the degree of organic matter alteration and the relative contents of individual PAHs and hopanes and geochemical indicators of thermal alteration are generally poor. The properties of the organic matter (its composition and rank), temperature fluctuations within the dumps, migration of organic compounds and mineral involvement are probably responsible for this. The processes taking place in coal waste dumps undergoing self-heating and self-combustion are complicated; they are very difficult to estimate and define. The methods of organic petrology and geochemistry give complementary data allowing the processes to be described. However, each of the dumps investigated represents a separate challenge to be surmounted in any regional attempt to delineate the regional environmental impact of these waste dumps.

Characterization of boron tolerant bacteria isolated from a fly ash dumping site for bacterial boron remediation.

PubMed

Edward Raja, Chellaiah; Omine, Kiyoshi

2013-08-01

Boron is an essential micronutrient for plants, but can above certain concentrations be toxic to living organisms. A major environmental concern is the removal of boron from contaminated water and fly ash. For this purpose, the samples were collected from a fly ash dumping site, Nagasaki prefecture, Japan. The chemical characteristics and heavy metal concentration of the samples were performed by X-ray fluorescent analysis and leaching test. For bacterial analysis, samples were collected in sterile plastic sheets and isolation was carried out by serial dilution method. The boron tolerant isolates that showed values of maximum inhibitory concentration toward boron ranging from 100 to 260 mM level were screened. Based on 16S rRNA sequencing and phylogenetic analysis, the isolates were most closely related to the genera Bacillus, Lysinibacillus, Microbacterium and Ralstonia. The boron tolerance of these strains was also associated with resistant to several heavy metals, such as As (III), Cr (VI), Cd, Cu, Pb, Ni, Se (III) and Zn. Indeed, these strains were arsenic oxidizing bacteria confirmed by silver nitrate test. These strains exhibited their salt resistances ranging from 4 to 15 % were determined in Trypticase soy agar medium. The boron tolerant strains were capable of removing 0.1-2.0 and 2.7-3.7 mg l(-1) boron from the medium and fly ash at 168 h. Thus, we have successfully identified the boron tolerant and removal bacteria from a fly ash dumping site for boron remediation.

Thermally induced processes in mixtures of aluminum with organic acids after plastic deformations under high pressure

NASA Astrophysics Data System (ADS)

Zhorin, V. A.; Kiselev, M. R.; Roldugin, V. I.

2017-11-01

DSC is used to measure the thermal effects of processes in mixtures of solid organic dibasic acids with powdered aluminum, subjected to plastic deformation under pressures in the range of 0.5-4.0 GPa using an anvil-type high-pressure setup. Analysis of thermograms obtained for the samples after plastic deformation suggests a correlation between the exothermal peaks observed around the temperatures of degradation of the acids and the thermally induced chemical reactions between products of acid degradation and freshly formed surfaces of aluminum particles. The release of heat in the mixtures begins at 30-40°C. The thermal effects in the mixtures of different acids change according to the order of acid reactivity in solutions. The extreme baric dependences of enthalpies of thermal effects are associated with the rearrangement of the electron subsystem of aluminum upon plastic deformation at high pressures.

40 CFR 227.14 - Criteria for evaluating the need for ocean dumping and alternatives to ocean dumping.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ocean dumping and alternatives to ocean dumping. 227.14 Section 227.14 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.14 Criteria for evaluating the need for ocean...

40 CFR 227.14 - Criteria for evaluating the need for ocean dumping and alternatives to ocean dumping.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ocean dumping and alternatives to ocean dumping. 227.14 Section 227.14 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.14 Criteria for evaluating the need for ocean...

40 CFR 227.14 - Criteria for evaluating the need for ocean dumping and alternatives to ocean dumping.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ocean dumping and alternatives to ocean dumping. 227.14 Section 227.14 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.14 Criteria for evaluating the need for ocean...

40 CFR 227.14 - Criteria for evaluating the need for ocean dumping and alternatives to ocean dumping.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ocean dumping and alternatives to ocean dumping. 227.14 Section 227.14 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.14 Criteria for evaluating the need for ocean...

40 CFR 227.14 - Criteria for evaluating the need for ocean dumping and alternatives to ocean dumping.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ocean dumping and alternatives to ocean dumping. 227.14 Section 227.14 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.14 Criteria for evaluating the need for ocean...

Early microbial biofilm formation on marine plastic debris.

PubMed

Lobelle, Delphine; Cunliffe, Michael

2011-01-01

An important aspect of the global problem of plastic debris pollution is plastic buoyancy. There is some evidence that buoyancy is influenced by attached biofilms but as yet this is poorly understood. We submerged polyethylene plastic in seawater and sampled weekly for 3 weeks in order to study early stage processes. Microbial biofilms developed rapidly on the plastic and coincided with significant changes in the physicochemical properties of the plastic. Submerged plastic became less hydrophobic and more neutrally buoyant during the experiment. Bacteria readily colonised the plastic but there was no indication that plastic-degrading microorganisms were present. This study contributes to improved understanding of the fate of plastic debris in the marine environment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Assessment of carbon footprint emissions and environmental concerns of solid waste treatment and disposal techniques; case study of Malaysia.

PubMed

Malakahmad, Amirhossein; Abualqumboz, Motasem S; Kutty, Shamsul Rahman M; Abunama, Taher J

2017-12-01

Malaysian authorities has planned to minimize and stop when applicable unsanitary dumping of waste as it puts human health and the environment at elevated risk. Cost, energy and revenue are mostly adopted to draw the blueprint of upgrading municipal solid waste management system, while the carbon footprint emissions criterion rarely acts asa crucial factor. This study aims to alert Malaysian stakeholders on the uneven danger of carbon footprint emissions of waste technologies. Hence, three scenarios have been proposed and assessed mainly on the carbon footprint emissions using the 2006 IPCC methodology. The first scenario is waste dumping in sanitary landfills equipped with gas recovery system, while the second scenario includes anaerobic digestion of organics and recycling of recyclable wastes such as plastic, glass and textile wastes. The third scenario is waste incineration. Besides the carbon footprint emissions criterion, other environmental concerns were also examined. The results showed that the second scenario recorded the lowest carbon footprint emissions of 0.251t CO 2 eq./t MSW while the third scenario had the highest emissions of 0.646t CO 2 eq./t MSW. Additionally, the integration between anaerobic digestion and recycling techniques caused the highest avoided CO 2 eq. emissions of 0.74t CO 2 eq./t MSW. The net CO 2 eq. emissions of the second scenario equaled -0.489t CO 2 eq./t MSW due to energy recovery from the biogas and because of recycled plastic, glass and textile wastes that could replace usage of raw material. The outcomes also showed that the first scenario generates huge amount of leachate and hazardous air constituents. The study estimated that a ton of dumped waste inside the landfills generates approximately 0.88m 3 of trace risky compounds and 0.188m 3 of leachate. As for energy production, the results showed that the third scenario is capable of generating 639kWh/t MSW followed by the second scenario with 387.59kWh/t MSW. The first scenario produced 296.79kWh/t MSW. In conclusion, the outcomes of this study recommend an integrated scenario of anaerobic digestion and recycling techniques to be employed in Malaysia. Copyright © 2017 Elsevier Ltd. All rights reserved.

An overview of the recent developments in polylactide (PLA) research.

PubMed

Madhavan Nampoothiri, K; Nair, Nimisha Rajendran; John, Rojan Pappy

2010-11-01

The concept of biodegradable plastics is of considerable interest with respect to solid waste accumulation. Greater efforts have been made in developing degradable biological materials without any environmental pollution to replace oil-based traditional plastics. Among numerous kinds of degradable polymers, polylactic acid sometimes called polylactide, an aliphatic polyester and biocompatible thermoplastic, is currently a most promising and popular material with the brightest development prospect and was considered as the 'green' eco friendly material. Biodegradable plastics like polyglycolic acid, polylactic acid, polycaprolactone, polyhydroxybutyrate, etc. are commercially available for controlled drug releases, implantable composites, bone fixation parts, packaging and paper coatings, sustained release systems for pesticides and fertilizers and compost bags etc. This review will provide information on current PLA market, brief account on recent developments in the synthesis of lactic acid (monomer of PLA) through biological route, PLA synthesis, unique material properties of PLA and modification of those by making copolymers and composites, PLA degradation and its wide spectrum applications.

Biotechnological approaches for the production of polyhydroxyalkanoates in microorganisms and plants - a review.

PubMed

Suriyamongkol, Pornpa; Weselake, Randall; Narine, Suresh; Moloney, Maurice; Shah, Saleh

2007-01-01

The increasing effect of non-degradable plastic wastes is a growing concern. Polyhydroxyalkanoates (PHAs), macromolecule-polyesters naturally produced by many species of microorganisms, are being considered as a replacement for conventional plastics. Unlike petroleum-derived plastics that take several decades to degrade, PHAs can be completely bio-degraded within a year by a variety of microorganisms. This biodegradation results in carbon dioxide and water, which return to the environment. Attempts based on various methods have been undertaken for mass production of PHAs. Promising strategies involve genetic engineering of microorganisms and plants to introduce production pathways. This challenge requires the expression of several genes along with optimization of PHA synthesis in the host. Although excellent progress has been made in recombinant hosts, the barriers to obtaining high quantities of PHA at low cost still remain to be solved. The commercially viable production of PHA in crops, however, appears to be a realistic goal for the future.

Process for remediation of plastic waste

DOEpatents

Pol, Vilas G [Westmont, IL; Thiyagarajan, Pappannan [Germantown, MD

2012-04-10

A single step process for degrading plastic waste by converting the plastic waste into carbonaceous products via thermal decomposition of the plastic waste by placing the plastic waste into a reactor, heating the plastic waste under an inert or air atmosphere until the temperature of 700.degree. C. is achieved, allowing the reactor to cool down, and recovering the resulting decomposition products therefrom. The decomposition products that this process yields are carbonaceous materials, and more specifically egg-shaped and spherical-shaped solid carbons. Additionally, in the presence of a transition metal compound, this thermal decomposition process produces multi-walled carbon nanotubes.

Biodegradability of plastics.

PubMed

Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

2009-08-26

Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

Biodegradability of Plastics

PubMed Central

Tokiwa, Yutaka; Calabia, Buenaventurada P.; Ugwu, Charles U.; Aiba, Seiichi

2009-01-01

Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed. PMID:19865515

Plastics in the North Atlantic garbage patch: A boat-microbe for hitchhikers and plastic degraders.

PubMed

Debroas, Didier; Mone, Anne; Ter Halle, Alexandra

2017-12-01

Plastic is a broad name given to different polymers with high molecular weight that impact wildlife. Their fragmentation leads to a continuum of debris sizes (meso to microplastics) entrapped in gyres and colonized by microorganisms. In the present work, the structure of eukaryotes, bacteria and Archaea was studied by a metabarcoding approach, and statistical analysis associated with network building was used to define a core microbiome at the plastic surface. Most of the bacteria significantly associated with the plastic waste originated from non-marine ecosystems, and numerous species can be considered as hitchhikers, whereas others act as keystone species (e.g., Rhodobacterales, Rhizobiales, Streptomycetales and Cyanobacteria) in the biofilm. The chemical analysis provides evidence for a specific colonization of the polymers. Alphaproteobacteria and Gammaproteobacteria significantly dominated mesoplastics consisting of poly(ethylene terephthalate) and polystyrene. Polyethylene was also dominated by these bacterial classes and Actinobacteria. Microplastics were made of polyethylene but differed in their crystallinity, and the majorities were colonized by Betaproteobacteria. Our study indicated that the bacteria inhabiting plastics harboured distinct metabolisms from those present in the surrounding water. For instance, the metabolic pathway involved in xenobiotic degradation was overrepresented on the plastic surface. Copyright © 2017 Elsevier B.V. All rights reserved.

Macrofouling communities and the degradation of plastic bags in the sea: an in situ experiment.

PubMed

Pauli, Nora-Charlotte; Petermann, Jana S; Lott, Christian; Weber, Miriam

2017-10-01

The increasing amount of plastic littered into the sea may provide a new substratum for benthic organisms. These marine fouling communities on plastic have not received much scientific attention. We present, to our knowledge, the first comprehensive analysis of their macroscopic community composition, their primary production and the polymer degradation comparing conventional polyethylene (PE) and a biodegradable starch-based plastic blend in coastal benthic and pelagic habitats in the Mediterranean Sea. The biomass of the fouling layer increased significantly over time and all samples became heavy enough to sink to the seafloor. The fouling communities, consisting of 21 families, were distinct between habitats, but not between polymer types. Positive primary production was measured in the pelagic, but not in the benthic habitat, suggesting that large accumulations of floating plastic could pose a source of oxygen for local ecosystems, as well as a carbon sink. Contrary to PE, the biodegradable plastic showed a significant loss of tensile strength and disintegrated over time in both habitats. These results indicate that in the marine environment, biodegradable polymers may disintegrate at higher rates than conventional polymers. This should be considered for the development of new materials, environmental risk assessment and waste management strategies.

Comparative study on the migration of di-2-ethylhexyl phthalate (DEHP) and tri-2-ethylhexyl trimellitate (TOTM) into blood from PVC tubing material of a heart-lung machine.

PubMed

Eckert, Elisabeth; Münch, Frank; Göen, Thomas; Purbojo, Ariawan; Müller, Johannes; Cesnjevar, Robert

2016-02-01

Medical devices like blood tubing often consist of PVC material that requires the addition of plasticizers. These plasticizers may migrate into the blood leading to an exposure of the patients. In this study the migration behavior of three different blood tubing sets (PVC material with two different plasticizers and silicone as control material) applied on a heart-lung machine standardly used for cardiopulmonary bypass (CPB) in children was studied. We analyzed the total plasticizer migration by analysis of both, the parent compounds as well as their primary degradation products in blood. Additionally, the total mass loss of the tubing over perfusion time was examined. The PVC tubing plasticized with DEHP (di-2-ethylhexyl phthalate) was found to have the highest mass loss over time and showed a high plasticizer migration rate. In comparison, the migration of TOTM (tri-2-ethylhexyl trimellitate) and its primary degradation products was found to be distinctly lower (by a factor of approx. 350). Moreover, it was observed that the storage time of the tubing affects the plasticizer migration rates. In conclusion, the DEHP substitute TOTM promises to be an effective alternative plasticizer for PVC medical devices particularly regarding the decreased migration rate during medical procedures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

PubMed

Oberbeckmann, Sonja; Osborn, A Mark; Duhaime, Melissa B

2016-01-01

Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the PET substrate. Future research is required to investigate microscale functional interactions at the plastic surface.

Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris

PubMed Central

Osborn, A. Mark

2016-01-01

Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5–6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae—all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the PET substrate. Future research is required to investigate microscale functional interactions at the plastic surface. PMID:27487037

Physical properties of polyurethane plastic sheets produced from polyols from canola oil.

PubMed

Kong, Xiaohua; Narine, Suresh S

2007-07-01

Polyurethane (PUR) plastic sheets were prepared by reacting polyols synthesized from canola oil with aromatic diphenylmethane diisocyanate. The properties of the material were measured by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) as well as tensile properties measurements. The effect of stoichiometric balance (i.e., OH/NCO molar ratio) on the final properties was evaluated. The concentration of elastically active network chains (EANCs), nue, of the polymer networks was calculated using rubber elasticity theory. The glass transition temperatures (Tg) for the plastic sheets with OH/NCO molar ratios of 1.0/1.0, 1.0/1.1, and 1.0/1.2 were found to be 23, 41, and 43 degrees C, respectively. The kinetic studies of the degradation process of the PUR plastics showed three well-defined steps of degradation. The PUR plastic sheets with OH/NCO molar ratio 1.0/1.1 had the highest nue, lowest number-average molecule weight between cross-links, MC, and excellent mechanical properties, indicating that this is the optimum ratio in the PUR formulations.

Reevaluation of microplastics extraction efficiency with the aim of Munich Plastic Sediment Separator.

NASA Astrophysics Data System (ADS)

Zobkov, Mikhail; Esiukova, Elena; Grave, Aleksei; Khatmullina, Liliya

2017-04-01

Invading of microplastics into marine environment is known as a global ecological threat. Specific density of microplastics can vary significantly depending on a polymer type, technological processes of its production, additives, weathering, and biofouling. Plastic particles can sink or float on the sea surface, but with time, most of drifting plastics become negatively buoyant and sink to the sea floor due to biofouling or adherence of denser particles. As a result, the seabed becomes the ultimate repository for microplastic particles and fibres. A study of microplastics content in aquatic sediments is an important source of information about ways of their migration, sink and accumulation zones. The Munich Plastic Sediment Separator (MPSS), proposed by Imhoff et al. (2012), is considered as the most effective tool for microplastic extraction. However, we observed that the numbers of marine microplastics extracted with this tool from different kinds of bottom sediments were significantly underestimated. We examined the extraction efficiency of the MPSS by adding artificial reference particles (ARPs) to marine sediment sample before the extraction procedure. Extraction was performed by two different methods: the modified NOAA method and using the MPSS. The separation solution with specific density 1.5 g/ml was used. Subsequent cleaning, drying and microscope detection procedures were identical. The microplastics content was determined in supernatant fraction, in the bulk of the extraction solution, in spoil dump fraction of MPSS and in instrument wash-out. While the extraction efficiency from natural sediments of ARPs by the MPSS was really high (100% in most cases), the extraction efficiency of marine microplastics was up to 10 times lower than that obtained with modified NOAA method for the same samples. Less than 40% of the total marine microplastics content has been successfully extracted with the MPSS. Large amounts of marine microplastics were found in the spoil dump and in the bulk solution fractions of the MPSS. Changes in stirring and separation periods had weak impact on the extraction efficiency of ARPs and marine microplastics. Until now, we are unable to find effective working procedures for adequate extraction of marine microplastics with the MPSS. The MPSS was found to be a useful tool for microplastics extraction from large sediment samples for qualitative analysis and to obtain examination specimens. Applying the MPSS for quantitative microplastics analysis requires further testing and elaboration of standardized extraction procedures. The research is supported by the Russian Science Foundation, grant number 15-17-10020 (project MARBLE). Imhof, H. K., Schmid, J., Niessner, R., Ivleva, N. P., Laforsch, C. 2012. A novel, highly efficient method for the separation and quantification of plastic particles in sediments of aquatic environments. Limnology and Oceanography: Methods, 10(7), 524-537. DOI 10.4319/lom.2012.10.524

Learn about Ocean Dumping

EPA Pesticide Factsheets

Ocean dumping is regulated by the Marine Protection, Research and Sanctuaries Act (MPRSA). Learn about ocean dumping regulation including what materials can and cannot be dumped, the Ocean Dumping Management Program, and MPRSA history and accomplishments.

Identification by CI-mass spectrometry of an unexpected benzodiazepine degradation product

NASA Astrophysics Data System (ADS)

Buret, D.; Breton, D.; Clair, P.; Lafosse, M.

2006-01-01

The French Military Health Service (SSA) has developed an innovative drug product, as a treatment against neurotoxic organophosphate poisoning (NOP). It contains three drug substances: an anticholinergic, an anticonvulsant and a cholinesterase reactivator. Testing stability study, in normal conditions, over 18 months, for this speciality, has given unexpected results. Indeed, one of the drug substances, avizafone (pro-drug of diazepam), breaks down partially into a compound which migrates into the plastic container where this degradation product is demethylated after absorption. Mass spectrometry with negative chemical ionisation (negative CI-MS) was used, to monitor decomposition of the drug substance. This method first showed migration of the degradation product and has been used to monitor its evolution during the stability testing study. The demethylation seems to be due to an additive product present in the plastic. The degradation products remain trapped in the container holding the pharmaceutical formulation.

Plastic degradation by thermophilic Bacillus sp. BCBT21 isolated from composting agricultural residual in Vietnam

NASA Astrophysics Data System (ADS)

Dang, Thi Cam Ha; Thang Nguyen, Dang; Thai, Hoang; Chinh Nguyen, Thuy; Thu Hien Tran, Thi; Le, Viet Hung; Huynh Nguyen, Van; Bach Tran, Xuan; Phuong Thao Pham, Thi; Giang Nguyen, Truong; Nguyen, Quang Trung

2018-03-01

Three different kinds of plastic bags HL, VHL, and VN1 with different chemical nature were degraded by a novel thermophilic bacterial strain isolated from composting agricultural residual in Vietnam in shaking liquid medium at 55 °C after 30 d. The new strain was classified in the Bacillus genus by morphological property and sequence of partial 16Sr RNA coding gene and named as Bacillus sp. BCBT21. This strain could produce extracellular hydrolase enzymes including lipase, CMCase, xylanase, chitinase, and protease with different level of activity in the same media. After a 30-d treatment at 55 °C with Bacillus sp. BCBT21, all characteristics including properties and morphology of treated plastic bags had been significantly changed. The weight loss, structure and surface morphology of these bags as well as the change in the average molecular weight of VHL bag were detected. Especially, the average molecular weight of VHL bag was significantly reduced from 205 000 to 116 760. New metabolites from the treated bags indicated biodegradation occurring with the different pathways. This finding suggests that there is high potential to develop an effective integrated method for plastic bags degradation by a combination of extracellular enzymes from bacteria and fungi existing in the composting process.

The Potential of Lignolytic Trichoderma Isolates in LDPE (Low Density Polyethylene) Plastic Biodegradation

NASA Astrophysics Data System (ADS)

Hikmah, M.; Setyaningsih, R.; Pangastuti, A.

2018-03-01

Plastic is experiencing buildup in the environment. Biodegradation process can be used as an alternative for LDPE plastic degradation because the process is environmentally friendly. Some fungi of the genus Trichoderma are known to have a role in plastic biodegradation. This study aims to find out how the potential of that lignolytic Trichoderma spp. isolates in LDPE biodegradation. Five isolates were screened by growing on MSMB (mineral salt medium broth) emulsified LDPE powder, with 35 days incubation at 30°C and shaking at 80 rpm. TL1, TL4, and TL5 are the three most potential isolates, indicated by the growth marked by increasing colony size on screening media. They were then tested for biodegradability by growing the isolates in MSMA (mineral salt medium agar) which then inoculated by 4 sheets of sterile LDPE 1x3 cm2 above the colony surface, incubated for 5, 15, 25 and 35 days. The degredability assessment is done by measuring the weight loss of LDPE sheets after biodegradation treatment. The obtained degradability percentage of TL1, TL4, and TL5 are 4.87%, 7.12%, and 7,51% respectively. The visual micrograph of LDPE film by SEM showed the appearance of damage and unevenness on the surface of the post-degradation film.

40 CFR 221.5 - Processing fees.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be charged in connection with each application for a permit for dumping in an existing dump site... with each application for a permit for dumping in a dump site other than a dump site designated in this...

40 CFR 221.5 - Processing fees.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be charged in connection with each application for a permit for dumping in an existing dump site... with each application for a permit for dumping in a dump site other than a dump site designated in this...

49 CFR 176.97 - Prohibition of dump scows.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Prohibition of dump scows. 176.97 Section 176.97... Requirements for Barges § 176.97 Prohibition of dump scows. Dump scows are barges having cargo carrying compartments of the hopper type and fitted with a bottom dump or a side dump. This type of barge is prohibited...

49 CFR 176.97 - Prohibition of dump scows.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Prohibition of dump scows. 176.97 Section 176.97... Requirements for Barges § 176.97 Prohibition of dump scows. Dump scows are barges having cargo carrying compartments of the hopper type and fitted with a bottom dump or a side dump. This type of barge is prohibited...

Biodegradation of HDPE by Aspergillus spp. from marine ecosystem of Gulf of Mannar, India.

PubMed

Sangeetha Devi, Rajendran; Rajesh Kannan, Velu; Nivas, Duraisamy; Kannan, Kanthaiah; Chandru, Sekar; Robert Antony, Arokiaswamy

2015-07-15

High density polyethylene (HDPE) is the most commonly found non-degradable solid waste among the polyethylene. In this present study, HDPE degrading various fungal strains were isolated from the polyethylene waste dumped marine coastal area and screened under in vitro condition. Based on weight loss and FT-IR Spectrophotometric analysis, two fungal strains designated as VRKPT1 and VRKPT2 were found to be efficient in HDPE degradation. Through the sequence analysis of ITS region homology, the isolated fungi were identified as Aspergillus tubingensis VRKPT1 and Aspergillus flavus VRKPT2. The biofilm formation observed under epifluorescent microscope had shown the viability of fungal strains even after one month of incubation. The biodegradation of HDPE film nature was further investigated through SEM analysis. HDPE poses severe environmental threats and hence the ability of fungal isolates was proved to utilize virgin polyethylene as the carbon source without any pre-treatment and pro-oxidant additives. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sleep and protein synthesis-dependent synaptic plasticity: impacts of sleep loss and stress

PubMed Central

Grønli, Janne; Soulé, Jonathan; Bramham, Clive R.

2014-01-01

Sleep has been ascribed a critical role in cognitive functioning. Several lines of evidence implicate sleep in the consolidation of synaptic plasticity and long-term memory. Stress disrupts sleep while impairing synaptic plasticity and cognitive performance. Here, we discuss evidence linking sleep to mechanisms of protein synthesis-dependent synaptic plasticity and synaptic scaling. We then consider how disruption of sleep by acute and chronic stress may impair these mechanisms and degrade sleep function. PMID:24478645

Process for remediation of plastic waste

DOEpatents

Pol, Vilas G; Thiyagarajan, Pappannan

2013-11-12

A single step process for degrading plastic waste by converting the plastic waste into carbonaceous products via thermal decomposition of the plastic waste by placing the plastic waste into a reactor, heating the plastic waste under an inert or air atmosphere until the temperature of about 700.degree. C. is achieved, allowing the reactor to cool down, and recovering the resulting decomposition products therefrom. The decomposition products that this process yields are carbonaceous materials, and more specifically carbon nanotubes having a partially filled core (encapsulated) adjacent to one end of the nanotube. Additionally, in the presence of a transition metal compound, this thermal decomposition process produces multi-walled carbon nanotubes.

Magnetically operated beam dump for dumping high power beams in a neutral beamline

DOEpatents

Dagenhart, W.K.

1984-01-27

It is an object of this invention to provide a beam dump system for a neutral beam generator which lowers the time-averaged power density of the beam dump impingement surface. Another object of this invention is to provide a beam dump system for a neutral particle beam based on reionization and subsequent magnetic beam position modulation of the beam onto a beam dump surface to lower the time-averaged power density of the beam dump ion impingement surface.

Silicone-covered biodegradable magnesium-stent insertion in the esophagus: a comparison with plastic stents.

PubMed

Zhu, Yue-Qi; Yang, Kai; Edmonds, Laura; Wei, Li-Ming; Zheng, Reila; Cheng, Ruo-Yu; Cui, Wen-Guo; Cheng, Ying-Sheng

2017-01-01

We determined the feasibility of, and tissue response to silicone-covered biodegradable magnesium- and plastic-stent insertion into the esophagus in rabbits. The mechanical compression-recovery characteristics and degradation behaviors of the magnesium stent were investigated in vitro . A total of 45 rabbits were randomly divided into a magnesium- ( n = 15) and a plastic- ( n = 15) stent group, and underwent stent insertion into the lower third of the esophagus under fluoroscopic guidance; a control group ( n = 15) did not undergo the intervention. Esophagography was performed at 1, 2, and 4 weeks. Five rabbits in each group were euthanized at each time point for histological examination. Silicone-covered magnesium stents showed similar radial force to plastic stents ( p > 0.05). The magnesium stents degraded rapidly in an acidic solution, but 90.2% ± 3.1% of the residual mass was maintained after a 2-week degradation in a solution with a pH of 4.0. All stent insertions were well tolerated. Magnesium stents migrated in six rabbits (one at 1 week, one at 2 weeks and four at 4 weeks), and plastic stents migrated in three rabbits (one at 2 weeks and two at 4 weeks; p > 0.05). Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was similar in both stented groups ( p > 0.05), and the esophagus wall was found to be significantly thinner in the stented groups than in the control group ( p < 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ from the control group ( p > 0.05). Esophageal silicone-covered magnesium stents provided reliable support for at least 2 weeks, with acceptable migration rates and without causing severe injury or tissue reaction compared with plastic stents.

Silicone-covered biodegradable magnesium-stent insertion in the esophagus: a comparison with plastic stents

PubMed Central

Zhu, Yue-Qi; Yang, Kai; Edmonds, Laura; Wei, Li-Ming; Zheng, Reila; Cheng, Ruo-Yu; Cui, Wen-Guo; Cheng, Ying-Sheng

2016-01-01

Background: We determined the feasibility of, and tissue response to silicone-covered biodegradable magnesium- and plastic-stent insertion into the esophagus in rabbits. Methods: The mechanical compression–recovery characteristics and degradation behaviors of the magnesium stent were investigated in vitro. A total of 45 rabbits were randomly divided into a magnesium- (n = 15) and a plastic- (n = 15) stent group, and underwent stent insertion into the lower third of the esophagus under fluoroscopic guidance; a control group (n = 15) did not undergo the intervention. Esophagography was performed at 1, 2, and 4 weeks. Five rabbits in each group were euthanized at each time point for histological examination. Results: Silicone-covered magnesium stents showed similar radial force to plastic stents (p > 0.05). The magnesium stents degraded rapidly in an acidic solution, but 90.2% ± 3.1% of the residual mass was maintained after a 2-week degradation in a solution with a pH of 4.0. All stent insertions were well tolerated. Magnesium stents migrated in six rabbits (one at 1 week, one at 2 weeks and four at 4 weeks), and plastic stents migrated in three rabbits (one at 2 weeks and two at 4 weeks; p > 0.05). Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was similar in both stented groups (p > 0.05), and the esophagus wall was found to be significantly thinner in the stented groups than in the control group (p < 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ from the control group (p > 0.05). Conclusions: Esophageal silicone-covered magnesium stents provided reliable support for at least 2 weeks, with acceptable migration rates and without causing severe injury or tissue reaction compared with plastic stents. PMID:28286555

perf-dump

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

Gamblin, T.

perf-dump is a library for dumping performance data in much the same way physics simulations dump checkpoints. It records per-process, per-timestep, per-phase, and per-thread performance counter data and dumps this large data periodically into an HDF5 data file.

Deterioration pattern of six biodegradable, potentially low-environmental impact mulches in field conditions.

PubMed

Moreno, Marta M; González-Mora, Sara; Villena, Jaime; Campos, Juan A; Moreno, Carmen

2017-09-15

Polyethylene plastic mulches are widely used in agriculture due to the countless advantages they have. However, the environmental problems associated with their use have led us to look for alternative mulch materials which degrade naturally and quickly, impact the environment less and function satisfactorily. To this end, biodegradable plastics and paper mulches are being used, but aspects related to their degradation should be studied more in-depth. This work provides the deterioration pattern of six biodegradable mulch materials (i.e. vegetable starch, polylactic acid plastic films or paper mulches) in horticultural crop in the edaphoclimatic conditions of Central Spain in two situations: over the lifetime of the mulches and after being incorporated into the soil. In the first situation, the deterioration levels were evaluated by recording the puncture resistance, weight and area covered in the above-soil and the in-soil part, and after soil incorporation by the number of fragments, their surfaces and weight. In the above-soil part, biodegradable plastics experienced further deterioration, particularly with no crop, while the paper mulch remained practically intact. However, the in-soil paper experienced complete and rapid degradation. At 200 days after soil incorporation, mulch residues were scarce, with the environmental effects it entails. These findings offer practical implications regarding the type of crop. The measurement of the surface covered, rather than the weight, was shown to be a more reliable indicator of the degradation of mulches. Furthermore, visual estimation was found to underestimate the functionality of mulches in comparison to that of the measurement of the surface covered. Copyright © 2017 Elsevier Ltd. All rights reserved.

The second green revolution? Production of plant-based biodegradable plastics.

PubMed

Mooney, Brian P

2009-03-01

Biodegradable plastics are those that can be completely degraded in landfills, composters or sewage treatment plants by the action of naturally occurring micro-organisms. Truly biodegradable plastics leave no toxic, visible or distinguishable residues following degradation. Their biodegradability contrasts sharply with most petroleum-based plastics, which are essentially indestructible in a biological context. Because of the ubiquitous use of petroleum-based plastics, their persistence in the environment and their fossil-fuel derivation, alternatives to these traditional plastics are being explored. Issues surrounding waste management of traditional and biodegradable polymers are discussed in the context of reducing environmental pressures and carbon footprints. The main thrust of the present review addresses the development of plant-based biodegradable polymers. Plants naturally produce numerous polymers, including rubber, starch, cellulose and storage proteins, all of which have been exploited for biodegradable plastic production. Bacterial bioreactors fed with renewable resources from plants--so-called 'white biotechnology'--have also been successful in producing biodegradable polymers. In addition to these methods of exploiting plant materials for biodegradable polymer production, the present review also addresses the advances in synthesizing novel polymers within transgenic plants, especially those in the polyhydroxyalkanoate class. Although there is a stigma associated with transgenic plants, especially food crops, plant-based biodegradable polymers, produced as value-added co-products, or, from marginal land (non-food), crops such as switchgrass (Panicum virgatum L.), have the potential to become viable alternatives to petroleum-based plastics and an environmentally benign and carbon-neutral source of polymers.

Water Vapor Permeation in Plastics

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

Keller, Paul E.; Kouzes, Richard T.

Polyvinyl toluene (PVT) and polystyrene (PS) (referred to as “plastic scintillator”) are used for gamma ray detectors. A significant decrease in radiation detection performance has been observed in some PVT-based gamma-ray detectors in systems in outdoor environments as they age. Recent studies have revealed that plastic scintillator can undergo an environmentally related material degradation that adversely affects gamma ray detection performance under certain conditions and histories. A significant decrease in sensitivity has been seen in some gamma-ray detectors in some systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors,more » and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no aging effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. The objective of this report is to document the phenomenon of permeability of plastic scintillator to water vapor and to derive the relationship between time, temperature, humidity and degree of water penetration in plastic. Several conclusions are documented about the properties of water permeability of plastic scintillator.« less

From macroplastic to microplastic: Degradation of high-density polyethylene, polypropylene, and polystyrene in a salt marsh habitat.

PubMed

Weinstein, John E; Crocker, Brittany K; Gray, Austin D

2016-07-01

As part of the degradation process, it is believed that most plastic debris becomes brittle over time, fragmenting into progressively smaller particles. The smallest of these particles, known as microplastics, have been receiving increased attention because of the hazards they present to wildlife. To understand the process of plastic degradation in an intertidal salt marsh habitat, strips (15.2 cm × 2.5 cm) of high-density polyethylene, polypropylene, and extruded polystyrene were field-deployed in June 2014 and monitored for biological succession, weight, surface area, ultraviolet (UV) transmittance, and fragmentation. Subsets of strips were collected after 4 wk, 8 wk, 16 wk, and 32 wk. After 4 wk, biofilm had developed on all 3 polymers with evidence of grazing periwinkles (Littoraria irrorata). The accreting biofilm resulted in an increased weight of the polypropylene and polystyrene strips at 32 wk by 33.5% and 167.0%, respectively, with a concomitant decrease in UV transmittance by approximately 99%. Beginning at 8 wk, microplastic fragments and fibers were produced from strips of all 3 polymers, and scanning electron microscopy revealed surface erosion of the strips characterized by extensive cracking and pitting. The results suggest that the degradation of plastic debris proceeds relatively quickly in salt marshes and that surface delamination is the primary mechanism by which microplastic particles are produced in the early stages of degradation. Environ Toxicol Chem 2016;35:1632-1640. © 2016 SETAC. © 2016 SETAC.

Photoconversion of gasified organic materials into biologically-degradable plastics

DOEpatents

Weaver, P.F.; Pinching Maness.

1993-10-05

A process is described for converting organic materials (such as biomass wastes) into a bioplastic suitable for use as a biodegradable plastic. In a preferred embodiment the process involves thermally gasifying the organic material into primarily carbon monoxide and hydrogen, followed by photosynthetic bacterial assimilation of the gases into cell material. The process is ideally suited for waste recycling and for production of useful biodegradable plastic polymer. 3 figures.

Photoconversion of gasified organic materials into biologically-degradable plastics

DOEpatents

Weaver, Paul F.; Maness, Pin-Ching

1993-01-01

A process is described for converting organic materials (such as biomass wastes) into a bioplastic suitable for use as a biodegradable plastic. In a preferred embodiment the process involves thermally gasifying the organic material into primarily carbon monoxide and hydrogen, followed by photosynthetic bacterial assimilation of the gases into cell material. The process is ideally suited for waste recycling and for production of useful biodegradable plastic polymer.

Macrofouling communities and the degradation of plastic bags in the sea: an in situ experiment

PubMed Central

Petermann, Jana S.; Lott, Christian; Weber, Miriam

2017-01-01

The increasing amount of plastic littered into the sea may provide a new substratum for benthic organisms. These marine fouling communities on plastic have not received much scientific attention. We present, to our knowledge, the first comprehensive analysis of their macroscopic community composition, their primary production and the polymer degradation comparing conventional polyethylene (PE) and a biodegradable starch-based plastic blend in coastal benthic and pelagic habitats in the Mediterranean Sea. The biomass of the fouling layer increased significantly over time and all samples became heavy enough to sink to the seafloor. The fouling communities, consisting of 21 families, were distinct between habitats, but not between polymer types. Positive primary production was measured in the pelagic, but not in the benthic habitat, suggesting that large accumulations of floating plastic could pose a source of oxygen for local ecosystems, as well as a carbon sink. Contrary to PE, the biodegradable plastic showed a significant loss of tensile strength and disintegrated over time in both habitats. These results indicate that in the marine environment, biodegradable polymers may disintegrate at higher rates than conventional polymers. This should be considered for the development of new materials, environmental risk assessment and waste management strategies. PMID:29134070

Methods for Assessment of Biodegradability of Plastic Films in Soil †

PubMed Central

Yabannavar, Asha V.; Bartha, Richard

1994-01-01

Traditional and novel techniques were tested and compared for their usefulness in evaluating biodegrad-ability claims made for newly formulated “degradable” plastic film products. Photosensitized polyethylene (PE), starch-PE, extensively plasticized polyvinyl chloride (PVC), and polypropylene (PP) films were incorporated into aerobic soil. Biodegradation was measured for 3 months under generally favorable conditions. Carbon dioxide evolution, residual weight recovery, and loss of tensile strength measurements were supplemented, for some films, by gas chromatographic measurements of plasticizer loss and gel permeation chromatographic (GPC) measurement of polymer molecular size distribution. Six- and 12-week sunlight exposures of photosensitized PE films resulted in extensive photochemical damage that failed to promote subsequent mineralization in soil. An 8% starch-PE film and the plasticized PVC film evolved significant amounts of CO2 in biodegradation tests and lost residual weight and tensile strength, but GPC measurements demonstrated that all these changes were confined to the additives and the PE and PVC polymers were not degraded. Carbon dioxide evolution was found to be a useful screening tool for plastic film biodegradation, but for films with additives, polymer biodegradation needs to be confirmed by GPC. Photochemical cross-linking of polymer strands reduces solubility and may interfere with GPC measurements of polymer degradation. PMID:16349408

Photocatalytic degradation of polystyrene plastic under fluorescent light.

PubMed

Shang, Jing; Chai, Ming; Zhu, Yongfa

2003-10-01

Plastic is used widely all over the world, due to the fact that it is low cost, is easily processable, and has lightweight properties. However, the hazard of discarding waste plastic, so-called "white pollution", is becoming more and more severe. In this paper, solid-phase photocatalytic degradation of polystyrene (PS) plastic, one of the most common commercial plastics, over copper phthalocyanine (CuPc) sensitized TiO2 photocatalyst (TiO2/CuPc) has been investigated under fluorescent light irradiation in the air. UV-vis spectra show that TiO2/CuPc extends its photoresponse range to visible light, contrasting to only UV light absorption of pure TiO2. The PS photodegradation experiments exhibit that higher PS weight loss rate, lower PS average molecular weight, less amount of volatile organic compounds, and more CO2 can be obtained in the system of PS-(TiO2/CuPc), in comparison with the PS-TiO2 system. Therefore, PS photodegradation over TiO2 CuPc composite is more complete and efficient than over pure TiO2, suggesting the potential application of dye-sensitized TiO2 catalyst in the thorough photodegradation of PS plastic under fluorescent light. During the photodegradation of PS plastic, the reactive oxygen species generated on TiO2 or TiO2/CuPc particle surfaces play important roles in chain scission. The present study demonstrates that the combination of polymer plastic with dye-sensitized TiO2 catalyst in the form of thin film is a practical and useful way to photodegrade plastic contaminants in the sunlight.

Development of a dynamic headspace gas chromatography-mass spectrometry method for on-site analysis of sulfur mustard degradation products in sediments.

PubMed

Magnusson, R; Nordlander, T; Östin, A

2016-01-15

Sampling teams performing work at sea in areas where chemical munitions may have been dumped require rapid and reliable analytical methods for verifying sulfur mustard leakage from suspected objects. Here we present such an on-site analysis method based on dynamic headspace GC-MS for analysis of five cyclic sulfur mustard degradation products that have previously been detected in sediments from chemical weapon dumping sites: 1,4-oxathiane, 1,3-dithiolane, 1,4-dithiane, 1,4,5-oxadithiephane, and 1,2,5-trithiephane. An experimental design involving authentic Baltic Sea sediments spiked with the target analytes was used to develop an optimized protocol for sample preparation, headspace extraction and analysis that afforded recoveries of up to 60-90%. The optimized method needs no organic solvents, uses only two grams of sediment on a dry weight basis and involves a unique sample presentation whereby sediment is spread uniformly as a thin layer inside the walls of a glass headspace vial. The method showed good linearity for analyte concentrations of 5-200 ng/g dw, good repeatability, and acceptable carry-over. The method's limits of detection for spiked sediment samples ranged from 2.5 to 11 μg/kg dw, with matrix interference being the main limiting factor. The instrumental detection limits were one to two orders of magnitude lower. Full-scan GC-MS analysis enabled the use of automated mass spectral deconvolution for rapid identification of target analytes. Using this approach, analytes could be identified in spiked sediment samples at concentrations down to 13-65 μg/kg dw. On-site validation experiments conducted aboard the research vessel R/V Oceania demonstrated the method's practical applicability, enabling the successful identification of four cyclic sulfur mustard degradation products at concentrations of 15-308μg/kg in sediments immediately after being collected near a wreck at the Bornholm Deep dumpsite in the Baltic Sea. Copyright © 2015 Elsevier B.V. All rights reserved.

Microplastics in seafood: Benchmark protocol for their extraction and characterization.

PubMed

Dehaut, Alexandre; Cassone, Anne-Laure; Frère, Laura; Hermabessiere, Ludovic; Himber, Charlotte; Rinnert, Emmanuel; Rivière, Gilles; Lambert, Christophe; Soudant, Philippe; Huvet, Arnaud; Duflos, Guillaume; Paul-Pont, Ika

2016-08-01

Pollution of the oceans by microplastics (<5 mm) represents a major environmental problem. To date, a limited number of studies have investigated the level of contamination of marine organisms collected in situ. For extraction and characterization of microplastics in biological samples, the crucial step is the identification of solvent(s) or chemical(s) that efficiently dissolve organic matter without degrading plastic polymers for their identification in a time and cost effective way. Most published papers, as well as OSPAR recommendations for the development of a common monitoring protocol for plastic particles in fish and shellfish at the European level, use protocols containing nitric acid to digest the biological tissues, despite reports of polyamide degradation with this chemical. In the present study, six existing approaches were tested and their effects were compared on up to 15 different plastic polymers, as well as their efficiency in digesting biological matrices. Plastic integrity was evaluated through microscopic inspection, weighing, pyrolysis coupled with gas chromatography and mass spectrometry, and Raman spectrometry before and after digestion. Tissues from mussels, crabs and fish were digested before being filtered on glass fibre filters. Digestion efficiency was evaluated through microscopical inspection of the filters and determination of the relative removal of organic matter content after digestion. Five out of the six tested protocols led to significant degradation of plastic particles and/or insufficient tissue digestion. The protocol using a KOH 10% solution and incubation at 60 °C during a 24 h period led to an efficient digestion of biological tissues with no significant degradation on all tested polymers, except for cellulose acetate. This protocol appeared to be the best compromise for extraction and later identification of microplastics in biological samples and should be implemented in further monitoring studies to ensure relevance and comparison of environmental and seafood product quality studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

27 CFR 19.748 - Dump/batch records.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Dump/batch records. 19.748... OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Records and Reports Processing Account § 19.748 Dump/batch records. (a) Format of dump/batch records. Proprietor's dump/batch records shall contain, as...

Multispectral analysis of ocean dumped materials

NASA Technical Reports Server (NTRS)

Johnson, R. W.

1977-01-01

Remotely sensed data were collected in conjunction with sea-truth measurements in three experiments in the New York Bight. Pollution features of primary interest were ocean dumped materials, such as sewage sludge and acid waste. Sewage-sludge and acid-waste plumes, including plumes from sewage sludge dumped by the 'line-dump' and 'spot-dump' methods, were located, identified, and mapped. Previously developed quantitative analysis techniques for determining quantitative distributions of materials in sewage sludge dumps were evaluated, along with multispectral analysis techniques developed to identify ocean dumped materials. Results of these experiments and the associated data analysis investigations are presented and discussed.

Dump truck-related deaths in construction, 1992-2007.

PubMed

McCann, Michael; Cheng, Mei-Tai

2012-05-01

Dump trucks are universally used in construction and other industries to haul materials to the location and to remove waste materials. The source for dump truck-related fatality data was the Bureau of Labor Statistics Census of Fatal Occupational Injuries (CFOI) Research File. From 1992 to 2007, 829 construction workers were killed in dump truck-related incidents nationwide. Of those, 336 were dump truck operators with 215 deaths occurring in street and highway incidents. Another 343 deaths involved workers on foot, three-quarters struck by dump trucks. Sixty-four of the construction workers killed were maintaining dump trucks, 22 when caught between the truck frame and a falling dump truck bed. Of the 86 other deaths, 55 involved streets and highways. Recommendations include: (i) improving the reporting of seat belt usage in fatality reports; (ii) requiring use of seat belts; (iii) requiring the use of backup alarms, spotters, or other methods to alert dump truck operators to workers in their blind spots; (iv) prohibiting direct dumping at river banks and embankments; (v) using cameras or radar to enforce stopping at railway crossings; and (xi) enforcing worker safety practices (e.g., lockout/tagout procedures on elevated dump truck beds). Copyright © 2011 Wiley Periodicals, Inc.

Interaction between vegetable oil based plasticizer molecules and polyvinyl chloride, and their plasticization effect

NASA Astrophysics Data System (ADS)

Haryono, Agus; Triwulandari, Evi; Jiang, Pingping

2017-01-01

Plasticizer molecules are low molecular weight compounds that are widely used in polymer industries especially in polyvinyl chloride (PVC) resin. As an additive in PVC resin, the important role of plasticizer molecules is to improve the flexibility and processability of PVC by lowering the glass transition temperature (Tg). However, the commercial plasticizer like di(2-ethylhexyl)phthalate (DEHP) is known to cause liver cancer, at least in laboratory rats. DEHP can leach out from PVC into blood, certain drug solutions and fatty foods, which has been detected in the bloodstream of patients undergoing transfusion. Vegetable oil based plasticizers have some attractive properties such as non-toxic, bio-degradable, good heat and light stability, renewable resources, and environmentally friendly. Here we discussed the main results and development of vegetable oil based plasticizer, and especially palm oil based plasticizer. The interaction between plasticizer and polymer was discussed from the properties of the plasticized polymeric material.

Catalytic transformation of waste polymers to fuel oil.

PubMed

Keane, Mark A

2009-01-01

Waste not, want not: The increase in waste polymer generation, which continues to exceed recycle, represents a critical environmental burden. However, plastic waste may be viewed as a potential resource and, with the correct treatment, can serve as hydrocarbon raw material or as fuel oil, as described in this Minireview.Effective waste management must address waste reduction, reuse, recovery, and recycle. The consumption of plastics continues to grow, and, while plastic recycle has seen a significant increase since the early 1990s, consumption still far exceeds recycle. However, waste plastic can be viewed as a potential resource and can serve, with the correct treatment, as hydrocarbon raw material or as fuel oil. This Minireview considers the role of catalysis in waste polymer reprocessing and provides a critical overview of the existing waste plastic treatment technologies. Thermal pyrolysis results in a random scissioning of the polymer chains, generating products with varying molecular weights. Catalytic degradation provides control over the product composition/distribution and serves to lower significantly the degradation temperature. Incineration of waste PVC is very energy demanding and can result in the formation of toxic chloro emissions. The efficacy of a catalytic transformation of PVC is also discussed.

A process for complete biodegradation of shrimp waste by a novel marine isolate Paenibacillus sp. AD with simultaneous production of chitinase and chitin oligosaccharides.

PubMed

Kumar, Aditya; Kumar, Deepak; George, Nancy; Sharma, Prince; Gupta, Naveen

2018-04-01

Disposal of chitinaceous waste is a major problem of seafood industry. Most of the known chitinolytic organisms have been studied with respect to pure chitin as substrate. Use of these organisms for degradation of seafood waste has not been explored much. In present study a marine bacterium capable of proficiently degrading shrimp waste with co-production of value added products like chitinase and chitin oligosaccharides was isolated from seafood waste dumping sites. On 16s rRNA and biochemical analysis bacterium was found to be a novel species of genus Paenibacillus.Under optimized condition complete shrimp waste degradation (99%) was achieved along with chitinase yield of 20.01 IUml -1 . SEM and FTIR showed the structural changes and breakage of bonds typical to that of chitin, which indicated that this process can be used for the degradation of other chitinaceous material also. Thin layer chromatography revealed the presence of chitin oligosaccharides of various degree of polymerization in the hydrolysate. Complete degradation of shrimp waste by Paenibacillus sp. AD makes it a potential candidate for the bioremediation of seafood waste at large scale. Concomitant production of chitinase and chitin oligosaccharides further makes the process economical and commercially viable. Copyright © 2017 Elsevier B.V. All rights reserved.

Coal Mining and Post-Metallurgic Dumping Grounds and Their Connections with Exploitation of Raw Materials in the Region of Ruda Śląska

NASA Astrophysics Data System (ADS)

Jonczy, Iwona; Gawor, Łukasz

2017-06-01

Characteristics of mining and metallurgical waste dumps in Ruda Śląska was presented in this article. Special attention was paid to the relationship of waste material accumulated on the dumps with resources exploited on studied area. The possibilities of dumps management were also traced and two directions were indicated. The first one is associated with forming a biological covering on the dumps and the second one - with the dumps liquidation and with recovery areas now occupied by the dumps and thus with the secondary use of material collected on them.

Solid industrial wastes and their management in Asegra (Granada, Spain)

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

Casares, M.L.; Ulierte, N.; Mataran, A.

ASEGRA is an industrial area in Granada (Spain) with important waste management problems. In order to properly manage and control waste production in industry, one must know the quantity, type, and composition of industrial wastes, as well as the management practices of the companies involved. In our study, questionnaires were used to collect data regarding methods of waste management used in 170 of the 230 businesses in the area of study. The majority of these companies in ASEGRA are small or medium-size, and belong to the service sector, transport, and distribution. This was naturally a conditioning factor in both themore » type and management of the wastes generated. It was observed that paper and cardboard, plastic, wood, and metals were the most common types of waste, mainly generated from packaging (49% of the total volume), as well as material used in containers and for wrapping products. Serious problems were observed in the management of these wastes. In most cases they were disposed of by dumping, and very rarely did businesses resort to reuse, recycling or valorization. Smaller companies encountered greater difficulties when it came to effective waste management. The most frequent solution for the disposal of wastes in the area was dumping.« less

Survival of prokaryotes in a polluted waste dump during remediation by alkaline hydrolysis.

PubMed

Nielsen, Marie Bank; Kjeldsen, Kasper Urup; Lever, Mark Alexander; Ingvorsen, Kjeld

2014-04-01

A combination of culture-dependent and culture-independent techniques was used to characterize bacterial and archaeal communities in a highly polluted waste dump and to assess the effect of remediation by alkaline hydrolysis on these communities. This waste dump (Breakwater 42), located in Denmark, contains approximately 100 different toxic compounds including large amounts of organophosphorous pesticides such as parathions. The alkaline hydrolysis (12 months at pH >12) decimated bacterial and archaeal abundances, as estimated by 16S rRNA gene-based qPCR, from 2.1 × 10(4) and 2.9 × 10(3) gene copies per gram wet soil respectively to below the detection limit of the qPCR assay. Clone libraries constructed from PCR-amplified 16S rRNA gene fragments showed a significant reduction in bacterial diversity as a result of the alkaline hydrolysis, with preferential survival of Betaproteobacteria, which increased in relative abundance from 0 to 48 %. Many of the bacterial clone sequences and the 27 isolates were related to known xenobiotic degraders. An archaeal clone library from a non-hydrolyzed sample showed the presence of three main clusters, two representing methanogens and one representing marine aerobic ammonia oxidizers. Isolation of alkalitolerant bacterial pure cultures from the hydrolyzed soil confirmed that although alkaline hydrolysis severely reduces microbial community diversity and size certain bacteria survive a prolonged alkaline hydrolysis process. Some of the isolates from the hydrolyzed soil were capable of growing at high pH (pH 10.0) in synthetic media indicating that they could become active in in situ biodegradation upon hydrolysis.

Isotope biogeochemical assessment of natural biodegradation processes in open cast pit mining landscapes

NASA Astrophysics Data System (ADS)

Jeschke, Christina; Knöller, Kay; Koschorreck, Matthias; Ussath, Maria; Hoth, Nils

2014-05-01

In Germany, a major share of the energy production is based on the burning of lignite from open cast pit mines. The remediation and re-cultivation of the former mining areas in the Lusatian and Central German lignite mining district is an enormous technical and economical challenge. After mine closures, the surrounding landscapes are threatened by acid mine drainage (AMD), i.e. the acidification and mineralization of rising groundwater with metals and inorganic contaminants. The high content of sulfur (sulfuric acid, sulfate), nitrogen (ammonium) and iron compounds (iron-hydroxides) deteriorates the groundwater quality and decelerates sustainable development of tourism in (former) mining landscapes. Natural biodegradation or attenuation (NA) processes of inorganic contaminants are considered to be a technically low impact and an economically beneficial solution. The investigations of the stable isotope compositions of compounds involved in NA processes helps clarify the dynamics of natural degradation and provides specific informations on retention processes of sulfate and nitrogen-compounds in mine dump water, mine dump sediment, and residual pit lakes. In an active mine dump we investigated zones where the process of bacterial sulfate reduction, as one very important NA process, takes place and how NA can be enhanced by injecting reactive substrates. Stable isotopes signatures of sulfur and nitrogen components were examined and evaluated in concert with hydrogeochemical data. In addition, we delineated the sources of ammonium pollution in mine dump sediments and investigated nitrification by 15N-labeling techniques to calculate the limit of the conversion of harmful ammonium to nitrate in residual mining lakes. Ultimately, we provided an isotope biogeochemical assessment of natural attenuation of sulfate and ammonium at mine dump sites and mining lakes. Also, we estimated the risk potential for water in different compartments of the hydrological system. In laboratory experiments, we tested reactive materials that may speed up the process of bacterial sulfate reduction. In in-situ experiments, we quantified nitrification rates. Based on the results, we are able to suggest promising technical measures that enhance natural attenuation processes at mine dump site and in mining lakes. The natural water cycle in lignite mining landscapes is heavily impacted by human activities. Basically, nature is capable of cleaning itself to a certain extent after mining activities stopped. However, it is our responsibility to support biogeochemical processes to make them more efficient and more sustainable. Isotopic monitoring proved to be an excellent tool for assessing the relevance and performance of different re-cultivation measures for a positive long-term development of the water quality in large-scale aquatic systems affected by the impact of lignite mining.

Managing Ocean Dumping in EPA Region 4

EPA Pesticide Factsheets

Overview of ocean dumping in Southeast United States. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships

Managing Ocean Dumping in EPA Region 1

EPA Pesticide Factsheets

Overview of ocean dumping in New England, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships.

Managing Ocean Dumping in EPA Region 6

EPA Pesticide Factsheets

Overview of ocean dumping in South Central, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships

Managing Ocean Dumping in EPA Region 3

EPA Pesticide Factsheets

Overview of ocean dumping in Mid Atlantic, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships.

Managing Ocean Dumping in EPA Region 9

EPA Pesticide Factsheets

Overview of ocean dumping in EPA Pacific Southwest. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships.

Managing Ocean Dumping in EPA Region 10

EPA Pesticide Factsheets

Overview of ocean dumping in Pacific Northwest, US. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships.

40 CFR 228.15 - Dumping sites designated on a final basis.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Dumping sites designated on a final basis. 228.15 Section 228.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE MANAGEMENT OF DISPOSAL SITES FOR OCEAN DUMPING § 228.15 Dumping sites designated on a final basis. (a)(1) The sites...

40 CFR 228.15 - Dumping sites designated on a final basis.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Dumping sites designated on a final basis. 228.15 Section 228.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE MANAGEMENT OF DISPOSAL SITES FOR OCEAN DUMPING § 228.15 Dumping sites designated on a final basis. (a)(1) The sites...

40 CFR 228.15 - Dumping sites designated on a final basis.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Dumping sites designated on a final basis. 228.15 Section 228.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE MANAGEMENT OF DISPOSAL SITES FOR OCEAN DUMPING § 228.15 Dumping sites designated on a final basis. (a)(1) The sites...

40 CFR 228.15 - Dumping sites designated on a final basis.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Dumping sites designated on a final basis. 228.15 Section 228.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE MANAGEMENT OF DISPOSAL SITES FOR OCEAN DUMPING § 228.15 Dumping sites designated on a final basis. (a)(1) The sites...

Tracking Stripped Proton Particles in SNS Ring Injection Momentum Dump Line

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

Wang, Jian-Guang

3D computer simulations are performed to study magnetic field distributions and particle trajectories along the SNS ring injection momentum dump line. Optical properties and transfer maps along the dump line are calculated. The stripped proton particle distributions on the dump window are analyzed. The study has provided useful information for the redesign of the SNS ring injection beam dump.

30 CFR 77.1608 - Dumping facilities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... weight of a loaded dump truck, trucks shall be dumped a safe distance back from the edge of the bank. (c... material. (d) Grizzlies, grates, and other sizing devices at dump and transfer points shall be anchored...

Managing Ocean Dumping in EPA Region 2

EPA Pesticide Factsheets

Overview of ocean dumping in NY, NJ and Puerto Rico. Includes materials dumped in the Region, ocean dumping permits issues, dredged material testing guidance, ocean disposal site descriptions and information, regional dredging teams and other partnerships

Modeling cutinase enzyme regulation in polyethylene terepthalate plastic biodegradation

NASA Astrophysics Data System (ADS)

Apri, M.; Silmi, M.; Heryanto, T. E.; Moeis, M. R.

2016-04-01

PET (Polyethylene terephthalate) is a plastic material that is commonly used in our daily life. The high production of PET and others plastics that can be up to three hundred million tons per year, is not matched by its degradation rate and hence leads to environmental pollution. To overcome this problem, we develop a biodegradation system. This system utilizes LC Cutinase enzyme produced by engineered escherichia coli bacteria to degrade PET. To make the system works efficaciously, it is important to understand the mechanism underlying its enzyme regulation. Therefore, we construct a mathematical model to describe the regulation of LC Cutinase production. The stability of the model is analyzed. We show that the designated biodegradation system can give an oscillatory behavior that is very important to control the amount of inclusion body (the miss-folded proteins that reduce the efficiency of the biodegradation system).

Modeling cutinase enzyme regulation in polyethylene terepthalate plastic biodegradation

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

Apri, M., E-mail: m.apri@math.itb.ac.id; Silmi, M.; Heryanto, T. E.

PET (Polyethylene terephthalate) is a plastic material that is commonly used in our daily life. The high production of PET and others plastics that can be up to three hundred million tons per year, is not matched by its degradation rate and hence leads to environmental pollution. To overcome this problem, we develop a biodegradation system. This system utilizes LC Cutinase enzyme produced by engineered escherichia coli bacteria to degrade PET. To make the system works efficaciously, it is important to understand the mechanism underlying its enzyme regulation. Therefore, we construct a mathematical model to describe the regulation of LCmore » Cutinase production. The stability of the model is analyzed. We show that the designated biodegradation system can give an oscillatory behavior that is very important to control the amount of inclusion body (the miss-folded proteins that reduce the efficiency of the biodegradation system).« less

Physico-chemical behaviour of β irradiated plastic materials currently used as packagings and medical products

NASA Astrophysics Data System (ADS)

Yagoubi, N.; Baillet, A.; Pellerin, F.; Ferrier, D.

1995-11-01

The combined chromatographic technics and thermal analysis constitute an informative methodology for studying the modifications which could occur following a radiotreatment of plastic material at different doses (25 to 100 kGy). Several plastic materials used as packagings (PVC, PE, PS) were investigated. SEC method coupled with UV and DDL detections was applied to document any changes in molecular weight distribution. Reticulation and scission were the main observed degradation phenomena. These structural modifications were supported by TGA data, while the DSC provided information on modifications in crystallinity. In addition, RP-HPLC was carried out for the evaluation of the radiochemical behaviour of the additives and monomers. Firstly we demonstrated the degradation of high molecular weight phenolic antioxidants in BHT within the PEVA. Secondly, the modifications of amino 6 caproic acid and ɛ caprolactam, present in polyamid 6, depend on the irradiation doses.

Genome Sequence of “Thalassospira australica” NP3b2T Isolated from St. Kilda Beach, Tasman Sea

PubMed Central

López-Pérez, Mario; Webb, Hayden K.; Crawford, Russell J.

2014-01-01

Here, we present the draft genome of “Thalassospira australica” NP3b2T, a potential poly(ethylene terephthalate) (PET) plastic biodegrader. This genomic information will enhance information on the genetic basis of metabolic pathways for the degradation of PET plastic. PMID:25395631

Considerations in the weathering of wood-plastic composites

Treesearch

Nicole M. Stark

2007-01-01

During weathering, wood-plastic composites (WPCs) can fade and lose stiffness and strength. Weathering variables that induce these changes include exposure to UV light and water. Each variable degrades WPCs independently, but can also act synergistically. Recent efforts have highlighted the need to understand how WPCs weather, and to develop schemes for protection. The...

Biodegradability and plasticizing effect of yerba mate extract on cassava starch edible films.

PubMed

Medina Jaramillo, Carolina; Gutiérrez, Tomy J; Goyanes, Silvia; Bernal, Celina; Famá, Lucía

2016-10-20

Biodegradable and edible cassava starch-glycerol based films with different concentrations of yerba mate extract (0, 5 and 20wt.%) were prepared by casting. The plasticizing effect of yerba mate extract when it was incorporated into the matrix as an antioxidant was investigated. Thermal degradation and biodegradability of the obtained biofilms were also studied. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FTIR), X-ray diffraction analysis (XRD), water absorbance, stability in different solutions and biodegradability studies were performed. The clear correlation among the results obtained from the different analysis confirmed the plasticizing effect of yerba mate extract on the starch-glycerol matrix. Also, the extract led to a decrease in the degradation time of the films in soil ensuring their complete biodegradability before two weeks and to films stability in acidic and alkaline media. The plasticizing effect of yerba mate extract makes it an attractive additive for starch films which will be used as packaging or coating; and its contribution to an earlier biodegradability will contribute to waste reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

NASA Astrophysics Data System (ADS)

Gardés, E.; Balanzat, E.; Ban-d'Etat, B.; Cassimi, A.; Durantel, F.; Grygiel, C.; Madi, T.; Monnet, I.; Ramillon, J.-M.; Ropars, F.; Lebius, H.

2013-02-01

We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/μm. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteriorating is not independent on particles' stopping power, thus illustrating that the radiation hardness of plastic scintillators can be strongly weakened under high excitation density in heavy ion environments.

Qualitative evaluation of rock weir field performance and failure mechanisms

USGS Publications Warehouse

Mooney, David M.; Holmquist-Johnson, Christopher L.; Holburn, Elaina

2007-01-01

River spanning loose-rock structures provide sufficient head for irrigation diversion, permit fish passage over barriers, protect banks, stabilize degrading channels, activate side channels, reconnect floodplains, and create in-channel habitat. These structures are called by a variety of names including rock weirs, alphabet (U-, A-, V-, W-) weirs, Jhooks, and rock ramps. These structures share the common characteristics of:Loose rock construction materials (individually placed or dumped rocks with little or no concrete);Extents spanning the width of the river channel; andAn abrupt change in the water surface elevation at low flows.

Specific Features of Dumping Syndrome after Various Types of Gastrectomy as Assessed by a Newly Developed Integrated Questionnaire, the PGSAS-45.

PubMed

Tanizawa, Yutaka; Tanabe, Kazuaki; Kawahira, Hiroshi; Fujita, Junya; Takiguchi, Nobuhiro; Takahashi, Masazumi; Ito, Yuichi; Mitsumori, Norio; Namikawa, Tsutomu; Oshio, Atsushi; Nakada, Koji

2016-01-01

Dumping syndrome is a well-known adverse outcome after gastrectomy, but the precise clinical features have not been described. The aim of this study was to examine global aspects of dumping syndrome and to explore factors affecting the intensity of dumping syndrome in a large cohort using a newly developed integrated questionnaire, the Post-Gastrectomy Syndrome Assessment Scale (PGSAS)-45. Eligible questionnaires retrieved from 2,368 patients after 6 types of gastrectomy were analyzed. The incidence, intensity and number of symptoms of early general, early abdominal and late dumping syndrome were examined across various types of gastrectomy, and clinical factors affecting the intensity of each category of dumping syndrome were identified by multiple regression analysis. Dumping syndromes occurred most frequently and strongly in patients who underwent total gastrectomy with Roux-en-Y (TGRY), followed by proximal gastrectomy (PG), distal gastrectomy with Billroth-I, distal gastrectomy with Roux-en-Y, pylorus-preserving gastrectomy (PPG) and local resection (LR), in that order. Significant positive correlations among different categories of dumping syndromes were observed. TGRY, female sex, younger age, division of the celiac branch of the vagus nerve, PG and shorter postoperative period were independently related to worse dumping syndrome. Dumping syndromes were most common after TGRY and least common after PPG and LR among the various gastrectomy procedures. Type of gastrectomy and several clinical factors were related to the intensity of dumping syndrome. PGSAS-45 could offer a useful tool for evaluating dumping syndrome after gastrectomy. © 2015 S. Karger AG, Basel.

Fungi are the predominant micro-organisms responsible for degradation of soil-buried polyester polyurethane over a range of soil water holding capacities.

PubMed

Barratt, S R; Ennos, A R; Greenhalgh, M; Robson, G D; Handley, P S

2003-01-01

To investigate the relationship between soil water holding capacity (WHC) and biodegradation of polyester polyurethane (PU) and to quantify and identify the predominant degrading micro-organisms in the biofilms on plastic buried in soil. High numbers of both fungi and bacteria were recovered from biofilms on soil-buried dumb-bell-shaped pieces of polyester PU after 44 days at 15-100% WHC. The tensile strength of the polyester PU was reduced by up to 60% over 20-80% soil WHC, but no reduction occurred at 15, 90 or 100% soil WHC. A PU agar clearance assay indicated that fungi, but not bacteria were, the major degrading organisms in the biofilms on polyester PU and 10-30% of all the isolated fungi were able to degrade polyester PU in this assay. A 5.8S rDNA sequencing identified 13 strains of fungi representing the three major colony morphology types responsible for PU degradation. Sequence homology matches identified these strains as Nectria gliocladioides (five strains), Penicillium ochrochloron (one strain) and Geomyces pannorum (seven strains). Geomyces pannorum was the predominant organism in the biofilms comprising 22-100% of the viable polyester PU degrading fungi. Polyester PU degradation was optimum under a wide range of soil WHC and the predominant degrading organisms were fungi. By identifying the predominant degrading fungi in soil and studying the optimum WHC conditions for degradation of PU it allows us to better understand how plastics are broken down in the environment such as in landfill sites.

Effective feather degradation and keratinase production by Bacillus pumilus GRK for its application as bio-detergent additive.

PubMed

Ramakrishna Reddy, M; Sathi Reddy, K; Ranjita Chouhan, Y; Bee, Hameeda; Reddy, Gopal

2017-11-01

An effecient feather-degrading bacterium was isolated from poultry dumping yard and identified as Bacillus pumilus GRK based on 16S rRNA sequencing. Complete feather degradation (98.3±1.52%) with high keratinase production (373±4 U/ml) was observed in 24h under optimized conditions (substrate 1% (w/w); inoculum size 4% (v/v); pH 10; 200rpm at 37°C) with feathers as sole carbon and nitrogen source in tap water. The fermented broth was enriched with amino acids like tryptophan (221.44µg/ml), isoleucine (15.0µg/ml), lysine (10.81µg/ml) and methionine (7.24µg/ml) suggesting its potential use as feed supplement. The keratinase produced was a detergent stable serine protease and its activity was further enhanced by Ca +2 and Mg +2 . Bacillus pumilus GRK keratinase was successfully utilised as bioadditive in detergent formulations for removing the blood stains from cloth without affecting its fiber and texture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evolution of Sphingomonad Gene Clusters Related to Pesticide Catabolism Revealed by Genome Sequence and Mobilomics of Sphingobium herbicidovorans MH

PubMed Central

Nielsen, Tue Kjærgaard; Rasmussen, Morten; Demanèche, Sandrine; Cecillon, Sébastien; Vogel, Timothy M.

2017-01-01

Abstract Bacterial degraders of chlorophenoxy herbicides have been isolated from various ecosystems, including pristine environments. Among these degraders, the sphingomonads constitute a prominent group that displays versatile xenobiotic-degradation capabilities. Four separate sequencing strategies were required to provide the complete sequence of the complex and plastic genome of the canonical chlorophenoxy herbicide-degrading Sphingobium herbicidovorans MH. The genome has an intricate organization of the chlorophenoxy-herbicide catabolic genes sdpA, rdpA, and cadABCD that encode the (R)- and (S)-enantiomer-specific 2,4-dichlorophenoxypropionate dioxygenases and four subunits of a Rieske non-heme iron oxygenase involved in 2-methyl-chlorophenoxyacetic acid degradation, respectively. Several major genomic rearrangements are proposed to help understand the evolution and mobility of these important genes and their genetic context. Single-strain mobilomic sequence analysis uncovered plasmids and insertion sequence-associated circular intermediates in this environmentally important bacterium and enabled the description of evolutionary models for pesticide degradation in strain MH and related organisms. The mobilome presented a complex mosaic of mobile genetic elements including four plasmids and several circular intermediate DNA molecules of insertion-sequence elements and transposons that are central to the evolution of xenobiotics degradation. Furthermore, two individual chromosomally integrated prophages were shown to excise and form free circular DNA molecules. This approach holds great potential for improving the understanding of genome plasticity, evolution, and microbial ecology. PMID:28961970

Ocean Literacy from kindergarten to secondary school: a vertically articulated curriculum on marine micro-plastics

NASA Astrophysics Data System (ADS)

Realdon, Giulia; Candussio, Giuliana; Manià, Marinella; Palamin, Serenella

2017-04-01

Marine micro-plastics are a relatively recent issue in research (Thompson et al. 2004), in the media and in education and, due to novelty and relevance, they are a suitable topic for addressing Ocean Literacy within science teaching to different age groups. In fact marine micro-plastics can be used to introduce Ocean Literacy and environmental science, but also traditional science subjects like biology, chemistry and Earth science, with a system approach focused on "understanding the Ocean's influence on humans and human influence on the Ocean". Inspired by the growing public interest for marine micro-plastics and by the lack of specific teaching activities in our country (Italy), we developed a vertically articulated curriculum on micro-plastics for students aged 5-15 years. Our proposal is based on a number of practical activities realized with different language and communication styles to be suitable for different age groups. For younger students (age 5-7) we use drama to address micro-plastics bioaccumulation in marine food chains: children act as fish of different trophic levels who pretend to "eat" micro-plastics models (built from plastic bottles) until the biggest fish is captured and ends up as a "meal" shared by other pupils. Teachers guide the performance and stimulate observations and remarks about the origin of micro-plastics and the correct management of plastic objects. The performance has been documented in a video and presented in a national teacher workshop (3 Giorni per la Scuola, Napoli 2015). For students aged 8-13 we propose observation and manipulation of common household plastic objects, followed by physical/chemical testing of different polymers to understand plastics characteristics that make these materials valuable but troublesome at the same time. Students then observe sand samples, taken from a local beach, containing natural components and man-made fragments (including micro-plastics), so they can directly experience the fate of dumped plastic, discussing more sustainable management of plastic objects. For older (14-16) students we introduce primary micro-plastics by means of personal care products containing micro-beads: students learn to recognize the presence of micro-beads by reading the product's composition, then measure micro-beads content of one of these products and calculate a possible annual dispersion of micro-beads from their town to the sea. Also this activity is followed by classroom discussion about possible solutions to micro-beads water pollution. Micro-plastics activities have been presented to 39 students' groups since November 2014 and have been evaluated though questionnaires given to class teachers. Lesson plans containing these activities have been published - and are freely accessible - in European and in Italian science teacher's journals (EIROforum Science in School, Pearson Italia Science Magazine).

Sources and sinks of plastic debris in estuaries: A conceptual model integrating biological, physical and chemical distribution mechanisms.

PubMed

Vermeiren, Peter; Muñoz, Cynthia C; Ikejima, Kou

2016-12-15

Micro- and macroplastic accumulation threatens estuaries worldwide because of the often dense human populations, diverse plastic inputs and high potential for plastic degradation and storage in these ecosystems. Nonetheless, our understanding of plastic sources and sinks remains limited. We designed conceptual models of the local and estuary-wide transport of plastics. We identify processes affecting the position of plastics in the water column; processes related to the mixing of fresh and salt water; and processes resulting from the influences of wind, topography, and organism-plastic interactions. The models identify gaps in the spatial context of plastic-organisms interactions, the chemical behavior of plastics in estuaries, effects of wind on plastic suspension-deposition cycles, and the relative importance of processes affecting the position in the water column. When interpreted in the context of current understanding, sinks with high management potential can be identified. However, source-sink patterns vary among estuary types and with local scale processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recent progress on thin-film encapsulation technologies for organic electronic devices

NASA Astrophysics Data System (ADS)

Yu, Duan; Yang, Yong-Qiang; Chen, Zheng; Tao, Ye; Liu, Yun-Fei

2016-03-01

Among the advanced electronic devices, flexible organic electronic devices with rapid development are the most promising technologies to customers and industries. Organic thin films accommodate low-cost fabrication and can exploit diverse molecules in inexpensive plastic light emitting diodes, plastic solar cells, and even plastic lasers. These properties may ultimately enable organic materials for practical applications in industry. However, the stability of organic electronic devices still remains a big challenge, because of the difficulty in fabricating commercial products with flexibility. These organic materials can be protected using substrates and barriers such as glass and metal; however, this results in a rigid device and does not satisfy the applications demanding flexible devices. Plastic substrates and transparent flexible encapsulation barriers are other possible alternatives; however, these offer little protection to oxygen and water, thus rapidly degrading the devices. Thin-film encapsulation (TFE) technology is most effective in preventing water vapor and oxygen permeation into the flexible devices. Because of these (and other) reasons, there has been an intense interest in developing transparent barrier materials with much lower permeabilities, and their market is expected to reach over 550 million by 2025. In this study, the degradation mechanism of organic electronic devices is reviewed. To increase the stability of devices in air, several TFE technologies were applied to provide efficient barrier performance. In this review, the degradation mechanism of organic electronic devices, permeation rate measurement, traditional encapsulation technologies, and TFE technologies are presented.

Degradation and depolymerization of plastic waste by local bacterial isolates and bubble column reactor

NASA Astrophysics Data System (ADS)

Hussein, Amal A.; Alzuhairi, Mohammed; Aljanabi, Noor H.

2018-05-01

Accumulation of plastics, especially Polyethylene terephthalate (PET), is an ever increasing ecological threat due to its excessive usage in everyday human life. Nowadays, there are many methods to get rid of plastic wastes including burning, recycling and burying. However, these methods are not very active since their long period, anaerobic conditions that increase the rate of toxic materials released into the environment. This work aims to study the biological degradation of PET microorganism isolated from soil sample. Thirty eight (38) bacterial isolates were isolated from ten soil and plastic waste sample collected from four different waste disposal sites in Baghdad city during different periods between December 2016 and March 2017. Isolation was performed using enrichment culture method (flasks method) by culturing the soil samples in flasks with MSM medium where there is no carbon source only PET. Results showed that Al-Za'farania sample gave a higher number of isolates (13 isolates), while other samples gave less number of isolates. Screening was performed depending on their ability to grow in liquid MSM which contains PET powder and pieces and change the color of the PET-emulsified liquid medium as well as their ability to form the clear zone on PET-MSM agar. The results showed that NH-D-1 isolate has the higher ability to degrade DPET and PET pieces. According to morphological, biochemical characterization and Vitek-2 technique, the most active isolate was identified as Acinetobacter baumannii.

Microwave pyrolysis of multilayer plastic waste (LDPE) using zeolite catalyst

NASA Astrophysics Data System (ADS)

Juliastuti, Sri Rachmania; Hendrianie, Nuniek; Ramadhan, Pandu Jati; Satria, Dama Husin

2017-05-01

To overcome the problem of garbage, especially plastic waste, environmental experts and scholars from various disciplines have conducted various studies and actions. One way to degrade the multilayer packaging plastic waste LDPE (Low Density Poliethylene) with microwave pyrolysis process by using natural zeolite catalysts. The purpose of this experiment was to determine the effect of temperature and time of microwave pyrolysis process by using natural zeolite catalyst to degrade the plastic waste LDPE and compare them. Pyrolysis process was done by using a closed glass reactor with a capacity of 500 ml, operated at a pressure of 1 atm and flowed nitrogen 0.5 1 / min. Plastic waste was LDPE, and natural zeolite was used as its catalyst. Sample was heated at temperature 300, 400, 500 or 550 °C and was kept during time variables of 45, 60, 75 and 90 minutes. Liquid product was analyzed by Gas Chromatography-Mass Spectrometry (GC-MS), raw material was analyzed by Fourier Transform Infrared (FTIR), and solid product was analyzed by X-Ray Fluorescene (XRF). From the experimental resulted in the best yield products of pyrolisis using natural zeolite at 550 °C and 90 minutes was 2.88 % of solid yield, 28.12 % of liquid yield and the highest hydrocarbon concentration of 19.02 %.

Modeling the Non-Linear Response of Fiber-Reinforced Laminates Using a Combined Damage/Plasticity Model

NASA Technical Reports Server (NTRS)

Schuecker, Clara; Davila, Carlos G.; Pettermann, Heinz E.

2008-01-01

The present work is concerned with modeling the non-linear response of fiber reinforced polymer laminates. Recent experimental data suggests that the non-linearity is not only caused by matrix cracking but also by matrix plasticity due to shear stresses. To capture the effects of those two mechanisms, a model combining a plasticity formulation with continuum damage has been developed to simulate the non-linear response of laminates under plane stress states. The model is used to compare the predicted behavior of various laminate lay-ups to experimental data from the literature by looking at the degradation of axial modulus and Poisson s ratio of the laminates. The influence of residual curing stresses and in-situ effect on the predicted response is also investigated. It is shown that predictions of the combined damage/plasticity model, in general, correlate well with the experimental data. The test data shows that there are two different mechanisms that can have opposite effects on the degradation of the laminate Poisson s ratio which is captured correctly by the damage/plasticity model. Residual curing stresses are found to have a minor influence on the predicted response for the cases considered here. Some open questions remain regarding the prediction of damage onset.

Thermal degradation products from PVC film in food-wrapping operations.

PubMed

Boettner, E A; Ball, G L

1980-07-01

Thermal degradation products of polyvinyl chloride (PVC) food-wrap films were studied under simulated supermarket conditons using a commercial wrapping machine with either a hot wire or a cool rod cutting device. A sampling hood was constructed around the wire/rod to confine and allow collection of thermal degradation products produced. Compounds analyzed and normal concentration ranges found included hydrogen chloride (1-10 micrograms per cut), plasticizer (1-50 micrograms per cut), benzene and toluene (each < 5-20 ng per cut), acrolein (25-150 ng per cut), and carbon monoxide (2-4 micrograms per cut) using the hot wire. Room air samples, collected during hot-wire cutting without the sampling hood, had < 0.25 ppm hydrogen chloride. Using the cool-rod cutting device hydrogen chloride, benzene, and toluene were not detected. Plasticizer was detected (25-86 micrograms per cut) using the cool rod.

Thermal Behaviour of Nanocomposites based on Glycerol Plasticized Thermoplastic Starch and Cellulose Nanocrystallites

NASA Astrophysics Data System (ADS)

Kaushik, Anupama; Kaur, Ramanpreet

2011-12-01

The objective of this study was to study the thermal behaviour of cellulose nanocrystals/TPS based nanocomposites. Nanocrystalline cellulose was isolated from cotton linters using sonochemical method and characterized through WAXRD & TEM. These nanocrystals were then dispersed in glycerol plasticized starch in varying proportions and films were cast. The thermal degradation of thermoplastic starch/cellulose nanocrystallite nanocomposites was studied using TGA under nitrogen atmosphere. Thermal degradation was carried out for nanocomposites at a rate of 10 °C/min and at different rates under nitrogen atmosphere namely 2, 5, 10, 20 and 40 °C/min for nanocomposites containing 10% cellulose nanocrystals. Ozawa and Flynn and Kissinger methods were used to determine the apparent activation energy of these nanocomposites. The addition of cellulose nanocrystallites produced a significant effect on the activation energy for thermal degradation of the composites materials in comparison with the matrix alone. These nanocomposites are potential applicant for food packaging applications.

Stenotrophomonas sp. RZS 7, a novel PHB degrader isolated from plastic contaminated soil in Shahada, Maharashtra, Western India.

PubMed

Wani, S J; Shaikh, S S; Tabassum, B; Thakur, R; Gulati, A; Sayyed, R Z

2016-12-01

This paper reports an isolation and identification of novel poly-β-hydroxybutyrate (PHB) degrading bacterium Stenotrophomonas sp. RZS 7 and studies on its extracellular PHB degrading depolymerase enzyme. The bacterium isolated from soil samples of plastic contaminated sites of municipal area in Shahada, Maharashtra, Western India. It was identified as Stenotrophomonas sp. RZS 7 based on polyphasic approach. The bacterium grew well in minimal salt medium (MSM) and produced a zone (4.2 mm) of PHB hydrolysis on MSM containing PHB as the only source of nutrient. An optimum yield of enzyme was obtained on the fifth day of incubation at 37 °C and at pH 6.0. Further increase in enzyme production was recorded with Ca 2+ ions, while other metal ions like Fe 2+ (1 mM) and chemical viz. mercaptoethanol severally affected the production of enzyme.

[Progress on biodegradation of polylactic acid--a review].

PubMed

Li, Fan; Wang, Sha; Liu, Weifeng; Chen, Guanjun

2008-02-01

Polylactic acid is a high molecular-weight polyester made from renewable resources such as corn or starch. It is a promising biodegradable plastic due to its mechanical properties, biocompatibility and biodegradability. To achieve natural recycling of polylactic acid, relative microorganisms and the underlying mechanisms in the biodegradation has become an important issue in biodegradable materials. Up to date, most isolated microbes capable of degrading polylactic acid belong to actinomycetes. Proteases secreted by these microorganisms are responsible for the degradation. However, subtle differences exist between these polylactic acid degrading enzymes and typical proteases with respect to substrate binding and catalysis. Amino acids relative to catalysis are postulated to be highly plastic allowing their catalytic hydrolysis of polylactic acid. In this paper we reviewed current studies on biodegradation of polylactic acid concerning its microbial, enzymatic reactions and the possible mechanisms. We also discussed the probability of biologically recycling PLA by applying highly efficient strains and enzymes.

40 CFR 227.15 - Factors considered.

Code of Federal Regulations, 2013 CFR

2013-07-01

... could be used; (c) The relative environmental risks, impact and cost for ocean dumping as opposed to....15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.15...

40 CFR 227.15 - Factors considered.

Code of Federal Regulations, 2012 CFR

2012-07-01

... could be used; (c) The relative environmental risks, impact and cost for ocean dumping as opposed to....15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.15...

40 CFR 227.15 - Factors considered.

Code of Federal Regulations, 2011 CFR

2011-07-01

... could be used; (c) The relative environmental risks, impact and cost for ocean dumping as opposed to....15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.15...

40 CFR 227.15 - Factors considered.

Code of Federal Regulations, 2014 CFR

2014-07-01

... could be used; (c) The relative environmental risks, impact and cost for ocean dumping as opposed to....15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Need for Ocean Dumping § 227.15...

The design of the electron beam dump unit of Turkish Accelerator Center (TAC)

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

Cite, L. H., E-mail: hcite@gantep.edu.tr; Yilmaz, M., E-mail: Mustafa.Yilmaz@gaziantep.edu.tr

The required simulations of the electron beam interactions for the design of electron beam dump unit for an accelerator which will operate to get two Infra-Red Free Electron Lasers (IR-FEL) covering the range of 3-250 microns is presented in this work. Simulations have been carried out to understand the interactions of a bulk of specially shaped of four different and widely used materials for the dump materials for a 77 pC, 40 MeV, 13 MHz repetition rate e-beam. In the simulation studies dump materials are chosen to absorb the 99% of the beam energy and to restrict the radio-isotope production in themore » bulk of the dump. A Lead shielding also designed around the dump core to prevent the leakage out of the all the emitted secondary radiations, e.g., neutrons, photons. The necessary dump material requirements, for the overall design considerations and the possible radiation originated effects on the dump unit, are discussed and presented.« less

Genome Sequence of "Thalassospira australica" NP3b2T Isolated from St. Kilda Beach, Tasman Sea.

PubMed

López-Pérez, Mario; Rodriguez-Valera, Francisco; Webb, Hayden K; Crawford, Russell J; Ivanova, Elena P

2014-11-13

Here, we present the draft genome of "Thalassospira australica" NP3b2(T), a potential poly(ethylene terephthalate) (PET) plastic biodegrader. This genomic information will enhance information on the genetic basis of metabolic pathways for the degradation of PET plastic. Copyright © 2014 López-Pérez et al.

Moisture Sorption in Artificially aged wood-plastic composites

Treesearch

B. Kristoffer Segerholm; Rebecca E. Ibach; Magnus E.P. Wålinder

2012-01-01

Moisture sorption in wood-plastic composites (WPCs) affects their durability and dimensional stability. In certain outdoor exposures, the moisture properties of WPCs are altered due to e.g. cracks induced by swelling and shrinkage of the components, as well as UV degradation or biological attack. The aim of this work was to study the effect of different artificial...

Wood-plastic composites with reduced moisture : effects of chemical modification on durability in the laboratory and field

Treesearch

Rebecca E. Ibach; Craig M. Clemons; Rebecca L. Schumann

2007-01-01

Although laboratory evaluations of wood-plastic composites (WPCs) are helpful in predicting long-term durability, field studies are needed to verify overall long-term durability. Field exposure can encompass numerous degradations i.e., fungal, ultraviolet light, moisture, wind, temperature, freeze/thaw, wet/ dry cycling, termites, mold, etc. that traditionally are...

Proteasome Inhibition Enhances the Induction and Impairs the Maintenance of Late-Phase Long-Term Potentiation

ERIC Educational Resources Information Center

Dong, Chenghai; Upadhya, Sudarshan C.; Ding, Lan; Smith, Thuy K.; Hegde, Ashok N.

2008-01-01

Protein degradation by the ubiquitin-proteasome pathway plays important roles in synaptic plasticity, but the molecular mechanisms by which proteolysis regulates synaptic strength are not well understood. We investigated the role of the proteasome in hippocampal late-phase long-term potentiation (L-LTP), a model for enduring synaptic plasticity.…

Eco-restoration of a high-sulphur coal mine overburden dumping site in northeast India: A case study

NASA Astrophysics Data System (ADS)

Dowarah, J.; Deka Boruah, H. P.; Gogoi, J.; Pathak, N.; Saikia, N.; Handique, A. K.

2009-10-01

Eco-restoration of mine overburden (OB) or abandoned mine sites is a major environmental concern. In the present investigation, an integrated approach was used to rejuvenate a high-sulphur mine OB dumping site in the Tirap Collieries, Assam, India, which is situated in the Indo-Burma mega-biodiversity hotspot. A mine OB is devoid of true soil character with poor macro and micronutrient content and contains elevated concentrations of trace and heavy metals. Planting of herbs, shrubs, cover crops and tree species at close proximity leads to primary and secondary sere state succession within a period of 3 to 5 years. A variety of plant species were screened for potential use in restoration: herbs, including Sccharum spontaneum, Cymbopogon winterianus Jowitt (citronella), and Cymbopogon flexuosus (lemon grass) cover plants, including Mimosa strigillosa, M. striata, and M. pigra; shrubs, including Sesbania rostrata (dhaincha) and Cassia streata (cassia); and tree species, including Gmelina arborea (gomari) and Dalbergia sissoo (sissoo). Amendment with unmined soil and bio-organic matter was required for primary establishment of some plant species. Management of these plant species at the site will ensure long term sustainable eco-restoration of the coal mine-degraded land.

Waste picker livelihoods and inclusive neoliberal municipal solid waste management policies: The case of the La Chureca garbage dump site in Managua, Nicaragua.

PubMed

Hartmann, Chris

2018-01-01

The modernization (i.e. mechanization, formalization, and capital intensification) and enclosure of municipal solid waste management (MSWM) systems threaten waste picker livelihoods. From 2009 to 2013, a major development project, embodying traditional neoliberal policies with inclusive social policies, transformed the Managua, Nicaragua, municipal solid waste site from an open-air dump where as many as 2,000 informal waste pickers toiled to a sanitary landfill. To investigate waste pickers' social and economic condition, including labor characteristics, household income, and poverty incidence, after the project's completion, 146 semi-structured survey questionnaires were administered to four communities adjacent to the landfill and 45 semi-structured interviews were completed with key stakeholders. Findings indicate that hundreds of waste pickers were displaced by the project, employment benefits from the project were unevenly distributed by neighborhood, and informal waste picking endures due to persistent impoverishment, thereby contributing to continued social and economic marginalization and environmental degradation. The findings highlight the limitations of inclusive neoliberal development efforts to transform MSWM in a low-income country. Copyright © 2017 Elsevier Ltd. All rights reserved.

30 CFR 77.1608 - Dumping facilities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Dumping facilities. 77.1608 Section 77.1608 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... Haulage § 77.1608 Dumping facilities. (a) Dumping locations and haulage roads shall be kept reasonably...

Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions.

PubMed

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-09-27

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs.

Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions

PubMed Central

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-01-01

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs. PMID:28904262

The Anaphase Promoting Complex Is Required for Memory Function in Mice

ERIC Educational Resources Information Center

Kuczera, Tanja; Stilling, Roman Manuel; Hsia, Hung-En; Bahari-Javan, Sanaz; Irniger, Stefan; Nasmyth, Kim; Sananbenesi, Farahnaz; Fischer, Andre

2011-01-01

Learning and memory processes critically involve the orchestrated regulation of de novo protein synthesis. On the other hand it has become clear that regulated protein degradation also plays a major role in neuronal plasticity and learning behavior. One of the key pathways mediating protein degradation is proteosomal protein destruction. The…

Nano-plastics in the aquatic environment.

PubMed

Mattsson, K; Hansson, L-A; Cedervall, T

2015-10-01

The amount of plastics released to the environment in modern days has increased substantially since the development of modern plastics in the early 1900s. As a result, concerns have been raised by the public about the impact of plastics on nature and on, specifically, aquatic wildlife. Lately, much attention has been paid to macro- and micro-sized plastics and their impact on aquatic organisms. However, micro-sized plastics degrade subsequently into nano-sizes whereas nano-sized particles may be released directly into nature. Such particles have a different impact on aquatic organisms than larger pieces of plastic due to their small size, high surface curvature, and large surface area. This review describes the possible sources of nano-sized plastic, its distribution and behavior in nature, the impact of nano-sized plastic on the well-being of aquatic organisms, and the difference of impact between nano- and micro-sized particles. We also identify research areas which urgently need more attention and suggest experimental methods to obtain useful data.

Diesel oil removal by immobilized Pseudoxanthomonas sp. RN402.

PubMed

Nopcharoenkul, Wannarak; Netsakulnee, Parichat; Pinyakong, Onruthai

2013-06-01

Pseudoxanthomonas sp. RN402 was capable of degrading diesel, crude oil, n-tetradecane and n-hexadecane. The RN402 cells were immobilized on the surface of high-density polyethylene plastic pellets at a maximum cell density of 10(8) most probable number (MPN) g(-1) of plastic pellets. The immobilized cells not only showed a higher efficacy of diesel oil removal than free cells but could also degrade higher concentrations of diesel oil. The rate of diesel oil removal by immobilized RN402 cells in liquid culture was 1,050 mg l(-1) day(-1). Moreover, the immobilized cells could maintain high efficacy and viability throughout 70 cycles of bioremedial treatment of diesel-contaminated water. The stability of diesel oil degradation in the immobilized cells resulted from the ability of living RN402 cells to attach to material surfaces by biofilm formation, as was shown by CLSM imaging. These characteristics of the immobilized RN402 cells, including high degradative efficacy, stability and flotation, make them suitable for the purpose of continuous wastewater bioremediation.

Production and degradation of polyhydroxyalkanoates in waste environment

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

Lee, S.Y.; Choi, J.

1999-06-01

Polyhydroxyalkanoates (PHAs) are energy/carbon storage materials accumulated under unfavorable growth condition in the presence of excess carbon source. PHAs are attracting much attention as substitute for non-degradable petrochemically derived plastics because of their similar material properties to conventional plastics and complete biodegradability under natural environment upon disposal. In this paper, PHA production and degradation in waste environment as well as its role in biological phosphorus removal are reviewed. In biological phosphorus removal process, bacteria accumulating polyphosphate (poly P) uptake carbon substrates and accumulate these as PHA by utilizing energy from breaking down poly P under anaerobic conditions. In the followingmore » aerobic condition, accumulated PHA is utilized for energy generation and for the regeneration of poly P. PHA production from waste has been investigated in order to utilize abundant organic compounds in waste water. Since PHA content and PHA productivity that can be obtained are rather low, PHA production from waste product should be considered as a coupled process for reducing the amount of organic waste. PHAs can be rapidly degraded to completion in municipal anaerobic sludge by various microorganisms.« less

The degradation potential of PET bottles in the marine environment: An ATR-FTIR based approach

NASA Astrophysics Data System (ADS)

Ioakeimidis, C.; Fotopoulou, K. N.; Karapanagioti, H. K.; Geraga, M.; Zeri, C.; Papathanassiou, E.; Galgani, F.; Papatheodorou, G.

2016-03-01

The dominance and persistence of plastic debris in the marine environment are well documented. No information exists in respect to their lifespan in the marine environment. Nevertheless, the degradation potential of plastic litter items remains a critical issue for marine litter research. In the present study, polyethylene terephthalate bottles (PETs) collected from the submarine environment were characterized using ATR-FTIR in respect to their degradation potential attributed to environmental conditions. A temporal indication was used as indicative to the years of presence of the PETs in the environment as debris. PETs seem to remain robust for approximately fifteen years. Afterwards, a significant decrease of the native functional groups was recorded; some even disappear; or new-not typical for PETs-are created. At a later stage, using the PET time series collected from the Saronikos Gulf (Aegean Sea-E. Mediterranean), it was possible to date bottles that were collected from the bottom of the Ionian Sea (W. Greece). It is the first time that such a study has been conducted with samples that were actually degraded in the marine environment.

Antifouling leaching technique for optical lenses

USGS Publications Warehouse

Strahle, William J.; Perez, C. L.; Martini, Marinna A.

1994-01-01

The effectiveness of optical lenses deployed in water less than 100 m deep is significantly reduced by biofouling caused by the settlement of macrofauna, such as barnacles, hydroids, and tunicates. However, machineable porous plastic rings can be used to dispense antifoulant into the water in front of the lens to retard macrofaunal growth without obstructing the light path. Unlike coatings which can degrade the optical performance, antifouling rings do not interfere with the instrument optics. The authors have designed plastic, reusable cup-like antifouling rings to slip over the optical lenses of a transmissometer. These rings have been used for several deployments on shallow moorings in Massachusetts Bay, MA and have increased the time before fouling degrades optical characteristics

Characteristics of liquid product from the pyrolysis of waste plastic mixture at low and high temperatures: influence of lapse time of reaction.

PubMed

Lee, Kyong-Hwan; Shin, Dae-Hyun

2007-01-01

Pyrolysis of a waste plastic mixture (high-density polyethylene: low-density polyethylene: polypropylene: polystyrene = 3:2:3:1) into a liquid product was carried out in a stirred semi-batch reactor at low (350 degrees C) and high (400 degrees C) temperatures. The effect of lapse time of reaction in the reactor and also degradation temperature on the characteristics of the liquid product from pyrolysis of the mixture was investigated. Liquid products were described by cumulative amount distribution, paraffin, olefin, naphthene and aromatic (PONA) distribution and molecular weight distribution. Their characteristic was quite differed with a lapse time of reaction and also at a low and high degradation temperatures, because of the different physicochemical properties of the plastic types in the mixture. With increase of lapse time of reaction, the order for the main products in PONA components obtained at 350 degrees C was firstly aromatic products and then olefin products, while at 400 degrees C the order was firstly aromatic products, then olefin products and finally paraffin products. The experiments also showed from the molecular weight distribution of liquid PONA components that the paraffin and olefin products had a wide distribution by mainly random scission of polymer, but in the case of olefin products were produced by an end-chain scission mechanism as well as random scission mechanism, as evidenced by much more light olefin products. This phenomenon was evident at a higher degradation temperature. Also, both the light olefin and naphthene products with a molecular weight of around 120, as a main product, showed a similar trend as a function of lapse time, which had a maximum fraction at 343 min (at 350 degrees C) and 83 min (at 400 degrees C). Among PONA components, the highest concentrations of aromatic products were obtained with a molecular weight of around 100 at the fastest lapse time of reaction, regardless of degradation temperature. It was concluded that the characteristics of liquid product on the pyrolysis of plastic mixtures were strongly influenced by lapse time of reaction and degradation temperature.

Can soda ash dumping grounds provide replacement habitats for digger wasps (Hymenoptera, Apoidea, Spheciformes)?

PubMed

Twerd, Lucyna; Krzyżyński, Maciej; Waldon-Rudzionek, Barbara; Olszewski, Piotr

2017-01-01

Published sources document a loss of biodiversity at an extreme rate, mainly because natural and semi-natural ecosystems are becoming fragmented and isolated, thus losing their biological functions. These changes significantly influence biological diversity, which is a complex phenomenon that changes over time. Contemporary ecologists must therefore draw attention to anthropogenic replacement habitats and increase their conservation status. In our studies we show the positive role of soda ash dumping grounds as an alternative habitat for digger wasps, especially the thermophilic species. In the years 2007-2010 we carried out investigations in postindustrial soda ash dumping grounds located in Central Poland. We demonstrated that these areas serve as replacement habitats for thermophilic species of Spheciformes and, indirectly, for their potential prey. The studies were conducted in three microhabitat types, varying in soil moisture, salinity and alkalinity, that were changing in the course of ecological succession. We trapped 2571 specimens belonging to 64 species of digger wasps. Species typical of open sunny spaces comprised 73% of the whole inventory. The obtained results suggest that the stage of succession determines the richness, abundance and diversity of Spheciformes. The most favorable conditions for digger wasps were observed in habitats at late successional stages. Our results clearly showed that these habitats were replacement habitats for thermophilous Spheciformes, including rare taxa that require genetic, species and ecosystem protection, according to the Biodiversity Convention. We showed that some types of industry might play a positive role in the preservation of taxa in the landscape, and that even degraded industrial wasteland can replace habitats under anthropopressure, serving as refugia of biological diversity, especially for disturbance-dependent species.

Can soda ash dumping grounds provide replacement habitats for digger wasps (Hymenoptera, Apoidea, Spheciformes)?

PubMed Central

Twerd, Lucyna; Krzyżyński, Maciej; Waldon-Rudzionek, Barbara; Olszewski, Piotr

2017-01-01

Background Published sources document a loss of biodiversity at an extreme rate, mainly because natural and semi-natural ecosystems are becoming fragmented and isolated, thus losing their biological functions. These changes significantly influence biological diversity, which is a complex phenomenon that changes over time. Contemporary ecologists must therefore draw attention to anthropogenic replacement habitats and increase their conservation status. In our studies we show the positive role of soda ash dumping grounds as an alternative habitat for digger wasps, especially the thermophilic species. Methodology/Principal findings In the years 2007–2010 we carried out investigations in postindustrial soda ash dumping grounds located in Central Poland. We demonstrated that these areas serve as replacement habitats for thermophilic species of Spheciformes and, indirectly, for their potential prey. The studies were conducted in three microhabitat types, varying in soil moisture, salinity and alkalinity, that were changing in the course of ecological succession. We trapped 2571 specimens belonging to 64 species of digger wasps. Species typical of open sunny spaces comprised 73% of the whole inventory. The obtained results suggest that the stage of succession determines the richness, abundance and diversity of Spheciformes. The most favorable conditions for digger wasps were observed in habitats at late successional stages. Conclusions/Significance Our results clearly showed that these habitats were replacement habitats for thermophilous Spheciformes, including rare taxa that require genetic, species and ecosystem protection, according to the Biodiversity Convention. We showed that some types of industry might play a positive role in the preservation of taxa in the landscape, and that even degraded industrial wasteland can replace habitats under anthropopressure, serving as refugia of biological diversity, especially for disturbance-dependent species. PMID:28423033

Evaluation of pulsed corona discharge plasma for the treatment of petroleum-contaminated soil.

PubMed

Li, Rui; Liu, Yanan; Mu, Ruiwen; Cheng, Wenyan; Ognier, Stéphanie

2017-01-01

Petroleum hydrocarbons released to the environment caused by leakage or illegal dumping pose a threat to human health and the natural environment. In this study, the potential of a pulsed corona discharge plasma system for treating petroleum-polluted soils was evaluated. This system removed 76.93 % of the petroleum from the soil in 60 min with an energy efficiency of 0.20 mg/kJ. Furthermore, the energy and degradation efficiencies for the remediation of soil contaminated by single polyaromatic hydrocarbons, such as phenanthrene and pyrene, were also compared, and the results showed that this technology had potential in organic-polluted soil remediation. In addition, the role of water molecules was investigated for their direct involvement in the formation and transportation of active species. The increase of soil moisture to a certain extent clearly benefitted degradation efficiency. Then, treated soils were analyzed by FTIR and GC-MS for proposing the degradation mechanism of petroleum. During the plasma discharging processes, the change of functional group and the detection of small aromatic hydrocarbons indicated that the plasma active species attached petroleum hydrocarbons and degradation occurred. This technique reported herein demonstrated significant potential for the remediation of heavily petroleum-polluted soil, as well as for the treatment of organic-polluted soils.

Novel bacterial consortia isolated from plastic garbage processing areas demonstrated enhanced degradation for low density polyethylene.

PubMed

Skariyachan, Sinosh; Manjunatha, Vishal; Sultana, Subiya; Jois, Chandana; Bai, Vidya; Vasist, Kiran S

2016-09-01

This study aimed to formulate novel microbial consortia isolated from plastic garbage processing areas and thereby devise an eco-friendly approach for enhanced degradation of low-density polyethylene (LDPE). The LDPE degrading bacteria were screened and microbiologically characterized. The best isolates were formulated as bacterial consortia, and degradation efficiency was compared with the consortia formulated using known isolates obtained from the Microbial Culture Collection Centre (MTCC). The degradation products were analyzed by FTIR, GC-FID, tensile strength, and SEM. The bacterial consortia were characterized by 16S ribosomal DNA (rDNA) sequencing. The formulated bacterial consortia demonstrated 81 ± 4 and 38 ± 3 % of weight reduction for LDPE strips and LDPE pellets, respectively, over a period of 120 days. However, the consortia formulated by MTCC strains demonstrated 49 ± 4 and 20 ± 2 % of weight reduction for LDPE strips and pellets, respectively, for the same period. Furthermore, the three isolates in its individual application exhibited 70 ± 4, 68 ± 4, and 64 ± 4 % weight reduction for LDPE strips and 21 ± 2, 28 ± 2, 24 ± 2 % weight reduction for LDPE pellets over a period of 120 days (p < 0.05). The end product analysis showed structural changes and formation of bacterial film on degraded LDPE strips. The 16S rDNA characterization of bacterial consortia revealed that these organisms were novel strains and designated as Enterobacter sp. bengaluru-btdsce01, Enterobacter sp. bengaluru-btdsce02, and Pantoea sp. bengaluru-btdsce03. The current study thus suggests that industrial scale-up of these microbial consortia probably provides better insights for waste management of LDPE and similar types of plastic garbage.

76 FR 33346 - Final Supplementary Rules for the Upper Snake Field Office, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-08

... were placed at key locations in the greater planning area and contained comment cards that helped... prohibiting recreational vehicle (RV) owners from dumping their tanks at the dump station at Byington. The... prohibited from emptying their tanks in the dump station at Byington boat access. The capacity of the dump...

7 CFR 58.228 - Dump hoppers, screens, mixers and conveyors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Dump hoppers, screens, mixers and conveyors. 58.228... Service 1 Equipment and Utensils § 58.228 Dump hoppers, screens, mixers and conveyors. The product contact surfaces of dump hoppers, screens, mixers and conveyors which are used in the process of transferring dry...

40 CFR 223.1 - Contents of special, emergency, general, and research permits; posting requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Contents of Ocean Dumping Permits Issued... the assessment of the impact of permitted dumping activities on the marine environment at the disposal...

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 223.1 - Contents of special, emergency, general, and research permits; posting requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Contents of Ocean Dumping Permits Issued... the assessment of the impact of permitted dumping activities on the marine environment at the disposal...

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 223.1 - Contents of special, emergency, general, and research permits; posting requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Contents of Ocean Dumping Permits Issued... the assessment of the impact of permitted dumping activities on the marine environment at the disposal...

40 CFR 223.1 - Contents of special, emergency, general, and research permits; posting requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Contents of Ocean Dumping Permits Issued... the assessment of the impact of permitted dumping activities on the marine environment at the disposal...

40 CFR 223.1 - Contents of special, emergency, general, and research permits; posting requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Contents of Ocean Dumping Permits Issued... the assessment of the impact of permitted dumping activities on the marine environment at the disposal...

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...

7 CFR 46.22 - Accounting for dumped produce.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Accounting for dumped produce. 46.22 Section 46.22... Market Receivers § 46.22 Accounting for dumped produce. A clear and complete record shall be maintained... justifying dumping shall be forwarded to the consignor or joint account partner with the accounting and a...

Formation of Mesoherpetobionts Communities on a Reclamated Coal Open Pit Dump

NASA Astrophysics Data System (ADS)

Luzyanin, Sergey; Eremeeva, Natalya

2017-11-01

The structure of the mesoherpetobionts arthropod communities of the reclamated dump of the Krasnobrodsky coal pit (Kemerovo region, Russia) has been studied. It was established that the pioneer grouping of mesoherpetobionts arthropod represented by classes of Chilopoda, Arachnida and Insecta-Ectognatha has been formed on the dump for two years after the soil deposition. From the Arachnida, the species of the order Aranei are the most active in the stocking of the dumps. From the class Chilopoda, the species of Lithobiomorpha appear the first on the dump. Insects from the following three orders, Heteroptera, Hymenoptera and especially Coleoptera take the main part in the expansion of dumps and the formation of primary communities. Among the Coleoptera, the beetles of the family of Carabidae (44 species, dynamic density 22.9 specimens/10 trapped per day) dominate. From them, small or medium-sized species are mainly involved in stocking the dumps. There are significant differences in the complexes of ground dump carabid beetles in comparison with the control group, differing in species composition of dominant species, species richness and species diversity parameters

A monograph on the remediation of hazardous phthalates.

PubMed

Benjamin, Sailas; Pradeep, Selvanesan; Josh, Moolakkariyil Sarath; Kumar, Sunil; Masai, Eiji

2015-11-15

Phthalates or phthalic acid esters are a group of xenobiotic and hazardous compounds blended in plastics to enhance their plasticity and versatility. Enormous quantities of phthalates are produced globally for the production of plastic goods, whose disposal and leaching out into the surroundings cause serious concerns to the environment, biota and human health. Though in silico computational, in vitro mechanistic, pre-clinical animal and clinical human studies showed endocrine disruption, hepatotoxic, teratogenic and carcinogenic properties, usage of phthalates continues due to their cuteness, attractive chemical properties, low production cost and lack of suitable alternatives. Studies revealed that microbes isolated from phthalate-contaminated environmental niches efficiently bioremediate various phthalates. Based upon this background, this review addresses the enumeration of major phthalates used in industry, routes of environmental contamination, evidences for health hazards, routes for in situ and ex situ microbial degradation, bacterial pathways involved in the degradation, major enzymes involved in the degradation process, half-lives of phthalates in environments, etc. Briefly, this handy module would enable the readers, environmentalists and policy makers to understand the impact of phthalates on the environment and the biota, coupled with the concerted microbial efforts to alleviate the burden of ever increasing load posed by phthalates. Copyright © 2015 Elsevier B.V. All rights reserved.

New plastic recycling technology | Science Inventory | US EPA

EPA Pesticide Factsheets

Greater than 60% of the total plastic content of municipal solid waste is comprised of polyolefins (high-density, low-density, and linear polyethylene and polypropylene. Polyethylene (PE) is the largest-volume component but presents a challenge due to the absence of low-energy degradation processes. This news column provides a digest of recent technical reports relating to clean technology and environmental policy,

Plastic waste in the marine environment: A review of sources, occurrence and effects.

PubMed

Li, W C; Tse, H F; Fok, L

2016-10-01

This review article summarises the sources, occurrence, fate and effects of plastic waste in the marine environment. Due to its resistance to degradation, most plastic debris will persist in the environment for centuries and may be transported far from its source, including great distances out to sea. Land- and ocean-based sources are the major sources of plastic entering the environment, with domestic, industrial and fishing activities being the most important contributors. Ocean gyres are particular hotspots of plastic waste accumulation. Both macroplastics and microplastics pose a risk to organisms in the natural environment, for example, through ingestion or entanglement in the plastic. Many studies have investigated the potential uptake of hydrophobic contaminants, which can then bioaccumulate in the food chain, from plastic waste by organisms. To address the issue of plastic pollution in the marine environment, governments should first play an active role in addressing the issue of plastic waste by introducing legislation to control the sources of plastic debris and the use of plastic additives. In addition, plastics industries should take responsibility for the end-of-life of their products by introducing plastic recycling or upgrading programmes. Copyright © 2016 Elsevier B.V. All rights reserved.

An experimental study on dredge spoil of estuarine sediments in the bay of seine (France): A morphosedimentary assessment

NASA Astrophysics Data System (ADS)

Marmin, Stella; Lesueur, Patrick; Dauvin, Jean Claude; Samson, Sandrine; Tournier, Patrice; Gallicher Lavanne, Albert; Dubrulle-Brunaud, Carole; Thouroude, Coralie

2016-03-01

Studies on the consequences of dredging on estuarine morphology and its sedimentary dynamics are common, but the impacts of dumping dredge spoil in coastal open settings are rarely found in scientific literature. An experimental study was conducted over the period 2012-2013 to monitor the physical impacts of dredged material dumped at two adjacent sites (one million cubic metres at each) on the inner shelf of the Bay of Seine in France (eastern part of the English Channel, La Manche). As recently reinforced in the EU Marine Strategy Framework Directive (MSFD), knowledge on the location and intensity of human impacts (e.g. on marine ecosystems) is critical for effective marine management and conservation. So, two methods of disposition were tested to evaluate the impacts of dumping on the environment and thus propose recommendations for future dumping. The strategy is based on a Before-After-Control-Impact (BACI) approach, in which the spatio-temporal variability was studied by analysing the morphological and sedimentological characteristics over a period of 28 months, from November 2011 to April 2014, also including recovery of the seafloor after cessation of the dumping activities. The first experimental dumping operation (MASED) was carried out regularly for 8 months at a single point and generating a conical deposit of 5 m in height, while the second dumping (MABIO) lasted for 12 months involving four steps in the dumping process. In the second case, a wider area was covered, leading to the formation of a smaller deposit of 2 m in height. The dumped deposits consisted of muddy fine sand, whereas the inner shelf seafloor in this area is covered with fine to medium sand. As a result, muddy fine sand accumulated at or near the two dumping sites, with a maximum mud (i.e. particles<63 μm or>4 Φ) content of 50% compared to<5% before dumping operations. Videos obtained from a LVB200 Seabotix ROV, highlighted the heterogeneity of the sea floor around the dumping areas. Due to hydrodynamic forcing (wave climate and tidal currents), about 50% (MABIO) and 75% (MASED) of the volume of dredged material remained at the end of the dumping periods. After dumping ceased, a further 5% of material for MABIO and 20% for MASED, was transported out of the study area. For the latter, a spreading of fine particles was observed extending from the conical deposit towards the south west. To favour long-term exploitation, a more dispersive dumping over a wider surface area is recommended (e.g. MABIO)

Fungal degradation of polyhydroxyalkanoates and a semiquantitative assay for screening their degradation by terrestrial fungi.

PubMed

Matavulj, M; Molitoris, H P

1992-12-01

The current problems with decreasing fossile resources and increasing environmental pollution by petrochemical-based plastics have stimulated investigations to find biosynthetic materials which are also biodegradable. Bacterial reserve materials such as polyhydroxyalkanoates (PHA) have been discovered to possess thermoplastic properties and can be synthesized from renewable resources. Poly-beta-hydroxybutyric acid (PHB) is at present the most promising PHA; and BIOPOL, its copolymer with poly-beta-hydroxy-valerate (PHV), is already industrially produced (ICI, UK), and used as packaging material (WELLA, FRG). According to the literature, PHA degradation has so far mainly been observed in bacteria; only under certain environmental conditions has fungal degradation of PHAs been indicated. Since fungi constitute an important part of microbial populations participating in degradation processes, a simple screening method for fungal degradation of BIOPOL, a PHA-based plastic, was developed. Several media with about 150 fungal strains from different terrestrial environments and belonging to different systematic and ecological groups were used. PHA depolymerization was tested on three PHB-based media, each with 0.1% BIOPOL or PHB homopolymer causing turbidity of the medium. The media contained either a comparatively low or high content of organic carbon (beside PHA) or were based on mineral medium with PHA as the principal source of carbon. The degradation activity was detectable due to formation of a clear halo around the colony (Petri plates) or a clear zone under the colony (test tubes).(ABSTRACT TRUNCATED AT 250 WORDS)

Evolution of Sphingomonad Gene Clusters Related to Pesticide Catabolism Revealed by Genome Sequence and Mobilomics of Sphingobium herbicidovorans MH.

PubMed

Nielsen, Tue Kjærgaard; Rasmussen, Morten; Demanèche, Sandrine; Cecillon, Sébastien; Vogel, Timothy M; Hansen, Lars Hestbjerg

2017-09-01

Bacterial degraders of chlorophenoxy herbicides have been isolated from various ecosystems, including pristine environments. Among these degraders, the sphingomonads constitute a prominent group that displays versatile xenobiotic-degradation capabilities. Four separate sequencing strategies were required to provide the complete sequence of the complex and plastic genome of the canonical chlorophenoxy herbicide-degrading Sphingobium herbicidovorans MH. The genome has an intricate organization of the chlorophenoxy-herbicide catabolic genes sdpA, rdpA, and cadABCD that encode the (R)- and (S)-enantiomer-specific 2,4-dichlorophenoxypropionate dioxygenases and four subunits of a Rieske non-heme iron oxygenase involved in 2-methyl-chlorophenoxyacetic acid degradation, respectively. Several major genomic rearrangements are proposed to help understand the evolution and mobility of these important genes and their genetic context. Single-strain mobilomic sequence analysis uncovered plasmids and insertion sequence-associated circular intermediates in this environmentally important bacterium and enabled the description of evolutionary models for pesticide degradation in strain MH and related organisms. The mobilome presented a complex mosaic of mobile genetic elements including four plasmids and several circular intermediate DNA molecules of insertion-sequence elements and transposons that are central to the evolution of xenobiotics degradation. Furthermore, two individual chromosomally integrated prophages were shown to excise and form free circular DNA molecules. This approach holds great potential for improving the understanding of genome plasticity, evolution, and microbial ecology. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Rapid biodegradation of plastics by mealworms (larvae of Tenebrio molitor) brings hope to solve wasteplastic pollution

NASA Astrophysics Data System (ADS)

Wu, W.; Yang, S.; Brandon, A. M.; Yang, Y.; Flanagan, J. A.; Fan, H. Q.; Cai, S. Y.; Wang, Z. Y.; Din, L. Y.; Daliang, N.; Yang, J.; Ren, J.; Tao, H. C.; Phillips, D.; Ren, N. Q.; Zhou, J.; Waymouth, R.; Criddle, C. S.

2016-12-01

Pollution of waste plastics in soil, river, ocean, landfill and potentially groundwater has been a major environment concern for decades. They include polystyrene (PS), polyethylene (PE) and others. Plastic particles could penetrate into groundwater and become potential threats to our groundwater Our recent research demonstrated that mealworm (larvae of Tenebrio molitor ), which are commercially used as animal and bird food and insect protein, can biodegrade PS and convert it to CO2 up within 48% within 12-14 hrs in mealworm gut. PS degradation was performed initially via depolymerization and then degradation within the mealworm guts. Gut microbiota plays a major role in PS biodegradation because the degradation is nearly completely inhibited when mealworms were fed with antibiotics. Physical and chemical analysis as well 13C labeled tests confirmed the biodegradation and mineralization of PS. The generality of plastic eating behavior of mealworms and biodegradation has been observed by testing mealworms from 11 different sources in China and the USA. All of the mealworms tested consume PS although at different relative rates. At ambient temperature (20-24 oC), the average daily consumption rate of PS ranged from 0.01 to 0.3 mg per 100 mealworms when fed PS alone. The mealworms also consumed low density polyethylene (LDPE) foam as sole diet. When mealworms were fed PS alone, the consumption rate and total amount consumed increased slightly as a function of temperature from 20 to 30 oC. Supplementing the diet with normal food (bran) enhanced the PS consumption rate and the total PS mass consumed. Microbial community analysis indicated that the microbial structure changed significantly after the diet was switched from normal food bran to PS or PS plus bran. PS-degrading bacterial strains have isolated and characterized. Our discoveries brings hopes to prevent or solve potential microplastics threats to groundwater.

Influence of Plasticizers on the Stability and Release of a Prodrug of Δ9-Tetrahydrocannabinol Incorporated in Poly (Ethylene Oxide) Matrices

PubMed Central

Thumma, Sridhar; ElSohly, Mahmoud A.; Zhang, Shuang-Qing; Gul, Waseem; Repka, Michael A.

2008-01-01

The objective of the present research was to stabilize a heat-labile novel prodrug of Δ9-tetrahydrocannabinol (THC), THC-hemiglutarate (THC-HG), in polyethylene oxide (PEO) [PolyOx® WSR N-80 (PEO N-80), MW 200,000 Daltons] polymeric matrix systems produced by hot-melt fabrication for systemic delivery of THC through the oral transmucosal route. For this purpose, the effects of processing conditions (processing temperature and heating duration), plasticizer type and concentration and storage conditions on the stability of the prodrug were investigated. The selected plasticizers studied included vitamin E succinate (VES), acetyltributyl citrate (ATBC), triethyl citrate (TEC), triacetin and polyethylene glycol 8000 (PEG 8000). Furthermore, the influence of plasticizer concentration on drug release was also studied. The stability of THC-HG in PEO matrices was influenced by all of the aforementioned variables. Films processed at 110 °C for 7 min were found to be favorable for hot-melt processing with a post- processing drug content of 95%, while significant degradation of THC-HG (~42%) was observed in those processed at 200 °C for 15 min. The degradation of the prodrug during hot-melt fabrication and also upon storage was considerably reduced in the presence of the plasticizers investigated, VES being the most effective. Modulation of the microenvironmental pH to an acidic range via incorporation of citric acid in PEO-plasticizer matrices significantly improved the stability of the prodrug, with almost 90% of the theoretical drug remaining as opposed to only 15% remaining in PEO-only matrices when stored at 40 °C for up to 3 months. The release of drug from PEO matrices was influenced both by the plasticizer type and concentration. A faster release resulted from water-soluble plasticizers, PEG 8000 and triacetin, and with increasing concentration. However, a slower release was observed with an increase in concentration of water-insoluble plasticizers, VES and ATBC. PMID:18602993

Somatostatin and the dumping syndrome.

PubMed

Long, R G; Adrian, T E; Bloom, S R

1985-03-23

Infusion of somatostatin reduced the symptoms of the early dumping syndrome after oral glucose was given and also reduced the associated tachycardia and rise in packed cell volume. It inhibited the secretion of enteroglucagon, neurotensin, and vasoactive intestinal polypeptide, which are raised in patients with the dumping syndrome and may have an aetiological role. It also prevented the reactive hypoglycaemia of late dumping by inhibiting the release of gastric inhibitory polypeptide and insulin. Somatostatin, possibly through its inhibitory effects on hormonal secretion, may have a role in the management of patients with the early and late dumping syndrome.

Degradation of microbial polyesters.

PubMed

Tokiwa, Yutaka; Calabia, Buenaventurada P

2004-08-01

Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current.

PubMed

Baztan, Juan; Carrasco, Ana; Chouinard, Omer; Cleaud, Muriel; Gabaldon, Jesús E; Huck, Thierry; Jaffrès, Lionel; Jorgensen, Bethany; Miguelez, Aquilino; Paillard, Christine; Vanderlinden, Jean-Paul

2014-03-15

Coastal zones and the biosphere as a whole show signs of cumulative degradation due to the use and disposal of plastics. To better understand the manifestation of plastic pollution in the Atlantic Ocean, we partnered with local communities to determine the concentrations of micro-plastics in 125 beaches on three islands in the Canary Current: Lanzarote, La Graciosa, and Fuerteventura. We found that, in spite of being located in highly-protected natural areas, all beaches in our study area are exceedingly vulnerable to micro-plastic pollution, with pollution levels reaching concentrations greater than 100 g of plastic in 1l of sediment. This paper contributes to ongoing efforts to develop solutions to plastic pollution by addressing the questions: (i) Where does this pollution come from?; (ii) How much plastic pollution is in the world's oceans and coastal zones?; (iii) What are the consequences for the biosphere?; and (iv) What are possible solutions? Copyright © 2014 Elsevier Ltd. All rights reserved.

Innovative thermoplastic chitosan obtained by thermo-mechanical mixing with polyol plasticizers.

PubMed

Matet, Marie; Heuzey, Marie-Claude; Pollet, Eric; Ajji, Abdellah; Avérous, Luc

2013-06-05

Chitosan shows a degradation temperature lower than its melting point, which prevents its development in several applications. One way to overcome this issue is the plasticization of the carbohydrate. In this work plasticized chitosan was prepared by a thermo-mechanical kneading approach. The effects of different non-volatile polyol plasticizers (glycerol, xylitol and sorbitol) were investigated. The microstructure and morphology were determined using FTIR, XRD, TEM and SEM in order to understand the plasticization mechanism. Sorbitol, which is the highest molecular weight polyol used, resulted in plasticized chitosan with the highest thermal, mechanical and rheological properties. On the other hand, the sample plasticized with glycerol, the lowest molecular weight polyol, had the most important amorphous phase content and the lowest thermal, mechanical and rheological properties. Also, when the polyol content increased in the formulation, the plasticized chitosan was more amorphous and consequently its processability easier, while its properties decreased. Copyright © 2013 Elsevier Ltd. All rights reserved.

Advanced Polymer For Multilayer Insulating Blankets

NASA Technical Reports Server (NTRS)

Haghighat, R. Ross; Shepp, Allan

1996-01-01

Polymer resisting degradation by monatomic oxygen undergoing commercial development under trade name "Aorimide" ("atomic-oxygen-resistant imidazole"). Intended for use in thermal blankets for spacecraft in low orbit, useful on Earth in outdoor applications in which sunlight and ozone degrades other plastics. Also used, for example, to make threads and to make films coated with metals for reflectivity.

The Ubiquitin-Specific Protease 14 (USP14) Is a Critical Regulator of Long-Term Memory Formation

ERIC Educational Resources Information Center

Jarome, Timothy J.; Kwapis, Janine L.; Hallengren, Jada J.; Wilson, Scott M.; Helmstetter, Fred J.

2014-01-01

Numerous studies have suggested a role for ubiquitin-proteasome-mediated protein degradation in learning-dependent synaptic plasticity; however, very little is known about how protein degradation is regulated at the level of the proteasome during memory formation. The ubiquitin-specific protease 14 (USP14) is a proteasomal deubiquitinating enzyme…

Research Team Engineers a Better Plastic-Degrading Enzyme | News | NREL

Science.gov Websites

polyethylene terephthalate, or PET. While working to solve the crystal structure of PETase-a recently determine its structure to aid in protein engineering, but we ended up going a step further and accidentally discovery that PETase can also degrade polyethylene furandicarboxylate, or PEF, a bio-based substitute for

Mapping mine wastes and analyzing areas affected by selenium-rich water runoff in southeast Idaho using AVIRIS imagery and digital elevation data

USGS Publications Warehouse

Mars, J.C.; Crowley, J.K.

2003-01-01

Remotely sensed hyperspectral and digital elevation data from southeastern Idaho are combined in a new method to assess mine waste contamination. Waste rock from phosphorite mining in the area contains selenium, cadmium, vanadium, and other metals. Toxic concentrations of selenium have been found in plants and soils near some mine waste dumps. Eighteen mine waste dumps and five vegetation cover types in the southeast Idaho phosphate district were mapped by using Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) imagery and field data. The interaction of surface water runoff with mine waste was assessed by registering the AVIRIS results to digital elevation data, enabling determinations of (1) mine dump morphologies, (2) catchment watershed areas above each mine dump, (3) flow directions from the dumps, (4) stream gradients, and (5) the extent of downstream wetlands available for selenium absorption. Watersheds with the most severe selenium contamination, such as the South Maybe Canyon watershed, are associated with mine dumps that have large catchment watershed areas, high stream gradients, a paucity of downstream wetlands, and dump forms that tend to obstruct stream flow. Watersheds associated with low concentrations of dissolved selenium, such as Angus Creek, have mine dumps with small catchment watershed areas, low stream gradients, abundant wetlands vegetation, and less obstructing dump morphologies. ?? 2002 Elsevier Science Inc. All rights reserved.

Risk assessment predictions of open dumping area after closure using Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Pauzi, Nur Irfah Mohd; Radhi, Mohd Shahril Mat; Omar, Husaini

2017-10-01

Currently, there are many abandoned open dumping areas that were left without any proper mitigation measures. These open dumping areas could pose serious hazard to human and pollute the environment. The objective of this paper is to determine the risk assessment at the open dumping area after they has been closed using Monte Carlo Simulation method. The risk assessment exercise is conducted at the Kuala Lumpur dumping area. The rapid urbanisation of Kuala Lumpur coupled with increase in population lead to increase in waste generation. It leads to more dumping/landfill area in Kuala Lumpur. The first stage of this study involve the assessment of the dumping area and samples collections. It followed by measurement of settlement of dumping area using oedometer. The risk of the settlement is predicted using Monte Carlo simulation method. Monte Carlo simulation calculates the risk and the long-term settlement. The model simulation result shows that risk level of the Kuala Lumpur open dumping area ranges between Level III to Level IV i.e. between medium risk to high risk. These settlement (ΔH) is between 3 meters to 7 meters. Since the risk is between medium to high, it requires mitigation measures such as replacing the top waste soil with new sandy gravel soil. This will increase the strength of the soil and reduce the settlement.

Monitoring of Thermal and Gas Activities in Mining Dump Hedvika, Czech Republic

NASA Astrophysics Data System (ADS)

Surovka, D.; Pertile, E.; Dombek, V.; Vastyl, M.; Leher, V.

2017-10-01

The negative consequences of mining of the black coal is occurrence of extractive waste storage locations - mining dumps. The mining activities carried out within the area of Ostrava are responsible for at least six mine dumps of loose materials arising as wastes from mining of mineral resources, many of which show presence of thermal processes. The thermal activity in dumps is responsible for many hazardous substances that pollute the environment and harm human health in the surroundings. This paper deals with the results of the first phase of project CZ.11.4.120/0.0/0.0/15_006/0000074 TERDUMP, on exploration of thermally active mining dumps are published in the article. As a first studied thermally active dump was a Hedvika dump. To localize of hot spots with hot gas emission was used a thermovision scanning by drone. The place with high temperature (49.8 °C) identified natural gas emission through natural cracks. Analysing the occurring pollutants in Hedvika Dump using the GC-MS or HPLC, respectively and the inert gases (CO2, CO and SO2) were determined by ion chromatography. The pollutants were determined in five sampling points during two measurements executed from July to August 2017.

PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENTOF DUMPING SYNDROME AND ITS RELATION TO BARIATRIC SURGERY

PubMed Central

CHAVES, Yasmin da Silva; DESTEFANI, Afrânio Côgo

2016-01-01

ABSTRACT Introduction The dumping syndrome is frequent in bariatric surgery. It is probably the most common syndrome following partial or complete gastrectomy. Its prevalence in partial gastrectomy can reach up to 50%, thus it can be a significant complication arising from some types of bariatric surgeries. Objective: Critical analysis on dumping syndrome, its pathophysiology, diagnosis and treatment. Methods: A literature review was performed using the key words: 'dumping syndrome', 'bariatric surgery' and 'rapid dumping syndrome'. Inclusion criteria were: books, original works, case reports and meta-analyzes, and the exclusion criterion was literature review. Concerning the publication time, articles were screened between 1960 and May 2015. Results: The dumping syndrome is complication arising from obesity surgeries, but also can be a result of vagus nerve damage. Diagnosis is done primarily through the use of questionnaires based on scores. Conclusion: The Sigstad score and Arts survey are valid means for assessing the dumping syndrome. Initial therapy consists in the adoption of dietary measures, short acting drugs administration. PMID:27683791

30 CFR 57.9301 - Dump site restraints.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Loading, Hauling, and Dumping Safety Devices, Provisions, and Procedures for Roadways, Railroads, and Loading and Dumping Sites...

NITRILE ELASTOMER-NYLON LAMINATES INCLUDING BARRIER FILMS.

DTIC Science & Technology

ADHESIVES, *NYLON, *NITRILE RUBBER , LAMINATES, LAMINATES, FILMS, TEXTILES, RUBBER COATINGS, BUTADIENES, ACRYLONITRILE POLYMERS, BONDING, ADHESION... DEGRADATION , MOISTUREPROOFING, PHENOLIC PLASTICS, HALOGENATED HYDROCARBONS, ISOCYANATES, CURING AGENTS, ELASTOMERS.

Cutinase-Like Enzyme from the Yeast Cryptococcus sp. Strain S-2 Hydrolyzes Polylactic Acid and Other Biodegradable Plastics

PubMed Central

Masaki, Kazuo; Kamini, Numbi Ramudu; Ikeda, Hiroko; Iefuji, Haruyuki

2005-01-01

A purified lipase from the yeast Cryptococcus sp. strain S-2 exhibited remote homology to proteins belonging to the cutinase family rather than to lipases. This enzyme could effectively degrade the high-molecular-weight compound polylactic acid, as well as other biodegradable plastics, including polybutylene succinate, poly (ɛ-caprolactone), and poly(3-hydroxybutyrate). PMID:16269800

Ultrafast dynamics of photoactive yellow protein via the photoexcitation and emission processes.

PubMed

Nakamura, Ryosuke; Hamada, Norio; Ichida, Hideki; Tokunaga, Fumio; Kanematsu, Yasuo

2007-01-01

Pump-dump fluorescence spectroscopy was performed for photoactive yellow protein (PYP) at room temperature. The effect of the dump pulse on the population of the potential energy surface of the electronic excited state was examined as depletion in the stationary fluorescence intensity. The dynamic behavior of the population in the electronic excited state was successfully probed in the various combinations of the pump-dump delay, the dump-pulse wavelength, the dump-pulse energy and the observation wavelength. The experimental results were compared with the results obtained by the femtosecond time-resolved fluorescence spectroscopy.

Somatostatin and the dumping syndrome.

PubMed Central

Long, R G; Adrian, T E; Bloom, S R

1985-01-01

Infusion of somatostatin reduced the symptoms of the early dumping syndrome after oral glucose was given and also reduced the associated tachycardia and rise in packed cell volume. It inhibited the secretion of enteroglucagon, neurotensin, and vasoactive intestinal polypeptide, which are raised in patients with the dumping syndrome and may have an aetiological role. It also prevented the reactive hypoglycaemia of late dumping by inhibiting the release of gastric inhibitory polypeptide and insulin. Somatostatin, possibly through its inhibitory effects on hormonal secretion, may have a role in the management of patients with the early and late dumping syndrome. PMID:2858244

Alternate seal configuration for lithium primary cells

NASA Technical Reports Server (NTRS)

Kelley, J. A.

1982-01-01

The problem of glass degradation in the glass-to-metal seals in lithium/sulfur dioxide cells is discussed. The glass degradation mechanism is attributed to lithium reacting with glass which is a result of deposition of lithium at the glass/metal/electrolyte interface. The worst degradation was observed when cells were stored in the inverted position. Alternate sealing methods were examined and a modified Ziegler seal is considered to be one of the best possible methods. The seal consists of a crimp type soft seal using a plastic annulus and a metal tube. Results of degradation tests are presented.

Analysis of Geodynamical Conditions of Region of Burning Coal Dumps Location

NASA Astrophysics Data System (ADS)

Batugin, Andrian; Musina, Valeria; Golovko, Irina

2017-12-01

Spontaneous combustion of coal dumps and their impact on the environment of mining regions remain important environmental problem, in spite of the measures that are being taken. The paper presents the hypothesis, which states that the location of coal dumps at the boundaries of geodynamically active crust blocks promotes the appearance of conditions for their combustion. At present geodynamically active crust faults that affect the operating conditions of engineering facilities are observed not only in the areas of tectonic activity, but also on platforms. According to the concept of geodynamical zoning, geodynamically dangerous zones for engineering structures can be not only large, well-developed crust faults, but also just formed fractures that appear as boundaries of geodynamically impacting and hierarchically ordered crust blocks. The purpose of the study is to estimate the linkage of burning dumps to boundaries of geodynamically active crust blocks (geodynamically dangerous zones) for subsequent development of recommendations for reducing environmental hazard. The analysis of 27 coal dumps location was made for one of the Eastern Donbass regions (Russia). Nine of sixteen burning dumps are located in geodynamically dangerous zones, which, taking into account relatively small area occupied by all geodynamically dangerous zones, results that there is a concentration (pcs/km2) of burning dumps, which is 14 times higher than the baseline value. While the probability of accidental obtaining of such a result is extremely low, this can be considered as the evidence of the linkage of burning dumps to geodynamically dangerous zones. Taking into account the stressed state of the rock massif in this region, all geodynamically dangerous zones can be divided into compression and tension zones. The statistic is limited, but nevertheless in tension zones the concentration of burning dumps is 2 times higher than in compression zones. Available results of thermal monitoring of burning dumps in this region also show that linearly extended firing sources oriented along geodynamically dangerous zones are observed. The obtained results show that geodynamical conditions of mining region, in which coal dumps are located, is important factor that impacts the creation of conditions for their spontaneous combustion and subsequent impact on the environment. Then this factor should be controlled by choosing the place for dumps location. It is proposed to carry out these works for the entire mining region of the Eastern Donbass, where there are more than 200 coal dumps.

Accelerated Aging Test for Plastic Scintillator Gamma Ray Detectors

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

Kouzes, Richard T.

Polyvinyl toluene (PVT) and polystyrene (PS), collectively referred to as “plastic scintillator,” are synthetic polymer materials used to detect gamma radiation, and are commonly used in instrumentation. Recent studies have revealed that plastic scintillator undergoes an environmentally related material degradation that adversely affects performance under certain conditions and histories. A significant decrease in gamma ray sensitivity has been seen in some detectors in systems as they age. The degradation of sensitivity of plastic scintillator over time is due to a variety of factors, and the term “aging” is used to encompass all factors. Some plastic scintillator samples show no agingmore » effects (no significant change in sensitivity over more than 10 years), while others show severe aging (significant change in sensitivity in less than 5 years). Aging effects arise from weather (variations in heat and humidity), chemical exposure, mechanical stress, light exposure, and loss of volatile components. The damage produced by these various causes can be cumulative, causing observable damage to increase over time. Damage may be reversible up to some point, but becomes permanent under some conditions. It has been demonstrated that exposure of plastic scintillator in an environmental chamber to 30 days of high temperature and humidity (90% relative humidity and 55°C) followed by a single cycle to cold temperature (-30°C) will produce severe fogging in all PVT samples. This thermal cycle will be referred to as the “Accelerated Aging Test.” This document describes the procedure for performing this Accelerated Aging Test.« less

Pyrolysis of plastic waste for liquid fuel production as prospective energy resource

NASA Astrophysics Data System (ADS)

Sharuddin, S. D. A.; Abnisa, F.; Daud, W. M. A. W.; Aroua, M. K.

2018-03-01

The worldwide plastic generation expanded over years because of the variety applications of plastics in numerous sectors that caused the accumulation of plastic waste in the landfill. The growing of plastics demand definitely affected the petroleum resources availability as non-renewable fossil fuel since plastics were the petroleum-based material. A few options that have been considered for plastic waste management were recycling and energy recovery technique. Nevertheless, several obstacles of recycling technique such as the needs of sorting process that was labour intensive and water pollution that lessened the process sustainability. As a result, the plastic waste conversion into energy was developed through innovation advancement and extensive research. Since plastics were part of petroleum, the oil produced through the pyrolysis process was said to have high calorific value that could be used as an alternative fuel. This paper reviewed the thermal and catalytic degradation of plastics through pyrolysis process and the key factors that affected the final end product, for instance, oil, gaseous and char. Additionally, the liquid fuel properties and a discussion on several perspectives regarding the optimization of the liquid oil yield for every plastic were also included in this paper.

Passive energy dump for superconducting coil protection

DOEpatents

Luton, J.N. Jr.

1973-01-16

The patent describes a passive resistance type energy dump for the protection of the coils of a superconducting magnet. Insertion heaters are immersed in a rigid container filled with a fusible alloy. The energy dump is connected across the coils of the superconducting magnet wherein individual heater elements are connected singly to the windings or otherwise according to the energy dumping requirements upon transition of the magnet to a normal state.

D0 Superconducting Solenoid Quench Data and Slow Dump Data Acquisition

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

Markley, D.; /Fermilab

1998-06-09

This Dzero Engineering note describes the method for which the 2 Tesla Superconducting Solenoid Fast Dump and Slow Dump data are accumulated, tracked and stored. The 2 Tesla Solenoid has eleven data points that need to be tracked and then stored when a fast dump or a slow dump occur. The TI555(Texas Instruments) PLC(Programmable Logic Controller) which controls the DC power circuit that powers the Solenoid, also has access to all the voltage taps and other equipment in the circuit. The TI555 constantly logs these eleven points in a rotating memory buffer. When either a fast dump(dump switch opens) ormore » a slow dump (power supply turns off) occurs, the TI555 organizes the respective data and will down load the data to a file on DO-CCRS2. This data in this file is moved over ethernet and is stored in a CSV (comma separated format) file which can easily be examined by Microsoft Excel or any other spreadsheet. The 2 Tesla solenoid control system also locks in first fault information. The TI555 decodes the first fault and passes it along to the program collecting the data and storing it on DO-CCRS2. This first fault information is then part of the file.« less

Design of an innovative, ecological portable waste compressor for in-house recycling of paper, plastic and metal packaging waste.

PubMed

Xevgenos, D; Athanasopoulos, N; Kostazos, P K; Manolakos, D E; Moustakas, K; Malamis, D; Loizidou, M

2015-05-01

Waste management in Greece relies heavily on unsustainable waste practices (mainly landfills and in certain cases uncontrolled dumping of untreated waste). Even though major improvements have been achieved in the recycling of municipal solid waste during recent years, there are some barriers that hinder the achievement of high recycling rates. Source separation of municipal solid waste has been recognised as a promising solution to produce high-quality recycled materials that can be easily directed to secondary materials markets. This article presents an innovative miniature waste separator/compressor that has been designed and developed for the source separation of municipal solid waste at a household level. The design of the system is in line with the Waste Framework Directive (2008/98/EC), since it allows for the separate collection (and compression) of municipal solid waste, namely: plastic (polyethylene terephthalate and high-density polyethylene), paper (cardboard and Tetrapak) and metal (aluminium and tin cans). It has been designed through the use of suitable software tools (LS-DYNA, INVENTROR and COMSOL). The results from the simulations, as well as the whole design process and philosophy, are discussed in this article. © The Author(s) 2015.

Ingestion and fragmentation of plastic carrier bags by the amphipod Orchestia gammarellus: Effects of plastic type and fouling load.

PubMed

Hodgson, D J; Bréchon, A L; Thompson, R C

2018-02-01

Inappropriate disposal of plastic debris has led to the contamination of marine habitats worldwide. This debris can be ingested by organisms; however, the extent to which chewing and gut transit modifies plastic debris is unclear. Detritivores, such as amphipods, ingest and shred natural organic matter and are fundamental to its breakdown. Here we examine ingestion and shredding of plastic carrier bags by Orchestia gammarellus. A laboratory experiment showed these amphipods shredded plastic carrier bags, generating numerous microplastic fragments (average diameter 488.59μm). The presence of a biofilm significantly increased the amount of shredding, but plastic type (conventional, degradable and biodegradable) had no effect. Subsequent field observations confirmed similar shredding occurred on the strandline. Rates of shredding will vary according to amphipod density; however, our data indicates that shredding by organisms could substantially accelerate the formation microplastics in the environment. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

The plastic-associated microorganisms of the North Pacific Gyre.

PubMed

Carson, Henry S; Nerheim, Magnus S; Carroll, Katherine A; Eriksen, Marcus

2013-10-15

Microorganisms likely mediate processes affecting the fate and impacts of marine plastic pollution, including degradation, chemical adsorption, and colonization or ingestion by macroorganisms. We investigated the relationship between plastic-associated microorganism communities and factors such as location, temperature, salinity, plankton abundance, plastic concentration, item size, surface roughness, and polymer type. Small plastic items from the surface of the North Pacific Gyre in 2011 were examined using scanning electron microscopy. Bacillus bacteria (mean 1664 ± 247 individuals mm(-2)) and pennate diatoms (1097 ± 154 mm(-2)) were most abundant, with coccoid bacteria, centric diatoms, dinoflagellates, coccolithophores, and radiolarians present. Bacterial abundance was patchy, but increased on foamed polystyrene. Diatom abundance increased on items with rough surfaces and at sites with high plastic concentrations. Morphotype richness increased slightly on larger fragments, and a biogeographic transition occurred between pennate diatom groups. Better characterizing this community will aid in understanding how it interacts with plastic pollution. Copyright © 2013 Elsevier Ltd. All rights reserved.

The uninsured and patient dumping: recent policy responses in indigent care.

PubMed Central

Rice, M. F.; Jones, W.

1991-01-01

This article discusses the uninsured population and the phenomenon known as "patient dumping"--the transfer of a patient from one hospital (typically a private hospital) to a public hospital because of the patient's lack of insurance or inability to pay. The uninsured are the most vulnerable to patient dumping. The growth of patient dumping, a profile of the uninsured who are most likely to be a minority, and an analysis of federal and state policy responses to patient dumping are all discussed. The need for reform of the American health care system is highlighted and the Canadian health system is suggested as an alternative model. PMID:1800761

15. CAR DUMP BUILDING, DETAIL SHOWING GRATES OVER COAL BINS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. CAR DUMP BUILDING, DETAIL SHOWING GRATES OVER COAL BINS AND CABLES UNDER CAR DUMP CONTROL HOUSE - Pennsylvania Railroad, Canton Coal Pier, Clinton Street at Keith Avenue (Canton area), Baltimore, Independent City, MD

Mössbauer, TEM/SAED and XRD investigation on waste dumps of the Valea lui Stan gold mines

NASA Astrophysics Data System (ADS)

Constantinescu, Serban Grigore; Udubasa, Sorin S.; Udubasa, Gheorghe; Kuncser, Victor; Popescu-Pogrion, Nicoleta; Mercioniu, Ionel; Feder, Marcel

2012-03-01

The complementary investigation techniques, Mössbauer spectroscopy, transmission electron microscopy with selected area electron diffraction (TEM/SAED), X-ray diffraction (XRD) have been used to investigate the fate of the Valea lui Stan, Romania, gold-ore nanoscale-minerals during the long time of residence in the waste dumps. The preliminary investigations showed such waste dumps to contain significant amount of metals which cannot be identified by conventional methods. An intense research activity started up in order to evaluate the possibilities to recycle Valea lui Stan waste dumps and to recover metals by chemical or phytoextraction procedures. The waste dumps naturally show different mineral constituents with clay minerals as major phases, observed by XRD-technique. Although the waste dumps materials have whitish-yellowish colours, MÖSSBAUER technique evidences the presence of the finely dispersed iron bearing minerals. The authors are focusing to inspect and analyze Fe-compounds in the samples collected from Valea lui Stan's waste dumps in order to identify the magnetic phases by Mössbauer technique.

Production of a biodegradable plastic-degrading enzyme from cheese whey by the phyllosphere yeast Pseudozyma antarctica GB-4(1)W.

PubMed

Watanabe, Takashi; Shinozaki, Yukiko; Suzuki, Ken; Koitabashi, Motoo; Yoshida, Shigenobu; Sameshima-Yamashita, Yuka; Kuze Kitamoto, Hiroko

2014-08-01

Cheese whey is a by-product of cheese production and has high concentrations of lactose (about 5%) and other nutrients. Pseudozyma antarctica produces a unique cutinase-like enzyme, named PaE, that efficiently degrades biodegradable plastics. A previous study showed that a combination of 1% oil and 0.5% lactose increased cutinase-like enzyme production by another species of yeast. In this study, to produce PaE from cheese whey, we investigated the effects of soybean oil on PaE production (expressed as biodegradable plastic-degrading activity) by P. antarctica growing on lactose or cheese whey. In flask cultures, the final PaE activity was only 0.03 U/ml when soybean oil was used as the sole carbon source, but increased to 1.79 U/ml when a limited amount of soybean oil (under 0.5%) was combined with a relatively high concentration of lactose (6%). Using a 5-L jar fermentor with lactose fed-batch cultivation and periodic soybean oil addition, about 14.6 U/ml of PaE was obtained after 5 days of cultivation. When the lactose was replaced with cheese whey, PaE production was 10.8 U/ml after 3 days of cultivation. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Phyto-bioconversion of hard coal in the Cynodon dactylon/coal rhizosphere.

PubMed

Igbinigie, Eric E; Mutambanengwe, Cecil C Z; Rose, Peter D

2010-03-01

Fundamental processes involved in the microbial degradation of coal and its derivatives have been well documented. A mutualistic interaction between plant roots and certain microorganisms to aid growth of plants such as Cynodon dactylon (Bermuda grass) on hard coal dumps has recently been suggested. In the present study coal bioconversion activity of nonmycorrhizal fungi was investigated in the C. dactylon/coal rhizosphere. Fungal growth on 2% Duff-agar, gutation formation on nitric acid treated coal and submerged culture activity in nitrogen-rich and -deficient broth formed part of the screening and selection of the fungi. The selected fungal isolates were confirmed to be found in pristine C. dactylon/coal rhizosphere. To simulate bioconversion, a fungal aliquot of this rhizosphere was used as inoculum for a Perfusate fixed bed bioreactor, packed with coal. The results demonstrate an enhanced coal bioconversion facilitated by low molecular weight organics and the bioconversion of coal may be initiated by an introduction of nitrogen moieties to the coal substrate. These findings suggest a phyto-bioconversion of hard coal involving plant and microbes occurring in the rhizosphere to promote the growth of C. dactylon. An understanding of this relationship can serve as a benchmark for coal dumps rehabilitation as well as for the industrial scale bioprocessing of hard coal.

Exploring Ultrafast Structural Dynamics for Energetic Enhancement or Disruption

DTIC Science & Technology

2016-03-01

it. In a pump -push/ dump probe experiment, a secondary laser pulse (push/ dump ) is used after the initial perturbation due to the pump pulse. The...increased. The pump -push/ dump probe technique is a difficult experiment that requires a highly stable laser source. Ultrafast pump -probe experiments...decomposition of solids. Journal of Applied Physics. 2001;89:4156–4166. 17. Kee TW. Femtosecond pump -push-probe and pump - dump -probe spectroscopy of

Efficiency of Low-Profile External Dumping at Open Pit Coal Mining in Kemerovo Region

NASA Astrophysics Data System (ADS)

Selyukov, Alexey; Ermolaev, Vyacheslav; Kostinez, Irina

2017-11-01

Kemerovo region is one of the largest industrial regions of Russia, with a raw material specialization. The rapid growth of the coal industry in recent years has been greatly facilitated by the expansion and development of open pit mining for coal seams extraction, accompanied by an increase in the volumes of overburden and the height of the dumps. There are about 400 objects in the Russian Federation Government Register of Waste Disposal Facilities 80% of which are dumps. Approaches both to external dumping and to the technical stage of reclamation currently contribute to the growth of geomorphic system's instability. Thus, it is proposed to slightly change the approaches to external dumping: the essence consists in the formation of an external dump of overburden, which in future would represent a favorable landscape unit of a flat surface relief used for subsequent differently directed purposes.

Quarry waste management and recovery: first results connected to Carrara marble ravaneti (Italy)

NASA Astrophysics Data System (ADS)

Antonella Dino, Giovanna; Chiappino, Claudia; Rossetti, Piergiorgio

2017-04-01

Quarry waste (QW) represents a huge economic and environmental issue, due to loss of resources and to economic and environmental costs connected to waste management and landfilling activities. In many cases, valuable Raw Materials (RM) and Secondary Raw Materials (SRM) can be supplied by enhancing the QW recovery. In Italy large amounts of QW have been and still are dumped: such materials, if their quality (chemical, mineralogical, physical characteristics) and quantity are adequate, and if the impacts connected to their management are positive, can represent a valuable resource for SRM exploitation. Several dimension stone quarries have been and are interested by researches as for QW exploitation. Some researches show positive results, which are the basis for QW recovery (both from waste streams and from quarry dumps exploitation): a noticeable example is represented by Carrara marble waste. The Carrara quarry basin is characterized by ca. one hundred quarries for colored and white marble exploitation. The waste production can be summarized in: 80 Mm3 waste present in old quarry dumps (Ravaneti) and 3 Mm3/y of waste stream from quarrying activities. At present only 0.5 Mm3/y of QW is exploited for SRM production, causing a huge loss of resource. This has been the background for a preliminary research, on Carrara marble Ravaneti characterization, which was carried out thanks to the close cooperation between University of Torino, Società Apuana Marmi srl, and SET srl. In 2015, two QW dumping areas, Calocara and Lorano, were selected as representative for sampling activities. Three main sample categories were individuated based on granulometry (0.5-4 mm, 0-25 mm, 0-150 mm) to be characterized (size distribution, density, Atterberg limits, Los Angeles test, freezing and heat tests, flat and shape indexes, geochemistry, mineralogy). The results obtained are promising: the physical characterization shows an attitude for Carrara QW to be recovered as crushed materials for embankments and armour stone. Furthermore, the mineralogical and geochemical analyses show that these materials, being composed of nearly pure CaCO3, could find a proper application in high value products, as filler for paper, rubber, paint, plastic, etc. These data need to be confirmed by other analyses, thus a systematic characterization of QW present in the different quarry dumps is going to be programmed. R&D is strategic to solve problems connected to QW and landscape management. The cooperation between private Companies, Research Centers and Local Authorities is fundamental to reach the target, in terms of experimentation of new products (for civil works and infrastructure, building industry, agronomy, high-tech, etc.). Furthermore, if the stone industry aims at guaranteeing the systematic and convenient SRM recovery from QW, a change in exploitation and working activities has to be planned (eg. selection of the potential SRMs; dedicated stock areas for selected SRM; proper treatments depending on the kinds of reuse; treatment-activity protocols to produce each new product, etc.).

Tracking of the nuclear wavepacket motion in cyanine photoisomerization by ultrafast pump-dump-probe spectroscopy.

PubMed

Wei, Zhengrong; Nakamura, Takumi; Takeuchi, Satoshi; Tahara, Tahei

2011-06-01

Understanding ultrafast reactions, which proceed on a time scale of nuclear motions, requires a quantitative characterization of the structural dynamics. To track such structural changes with time, we studied a nuclear wavepacket motion in photoisomerization of a prototype cyanine dye, 1,1'-diethyl-4,4'-cyanine, by ultrafast pump-dump-probe measurements in solution. The temporal evolution of wavepacket motion was examined by monitoring the efficiency of stimulated emission dumping, which was obtained from the recovery of a ground-state bleaching signal. The dump efficiency versus pump-dump delay exhibited a finite rise time, and it became longer (97 fs → 330 fs → 390 fs) as the dump pulse was tuned to longer wavelengths (690 nm → 950 nm → 1200 nm). This result demonstrates a continuous migration of the leading edge of the wavepacket on the excited-state potential from the Franck-Condon region toward the potential minimum. A slowly decaying feature of the dump efficiency indicated a considerable broadening of the wavepacket over a wide range of the potential, which results in the spread of a population distribution on the flat S(1) potential energy surface. The rapid migration as well as broadening of the wavepacket manifests a continuous nature of the structural dynamics and provides an intuitive visualization of this ultrafast reaction. We also discussed experimental strategies to evaluate reliable dump efficiencies separately from other ultrafast processes and showed a high capability and possibility of the pump-dump-probe method for spectroscopic investigation of unexplored potential regions such as conical intersections. © 2011 American Chemical Society

Review of the partitioning of chemicals into different plastics: Consequences for the risk assessment of marine plastic debris.

PubMed

O'Connor, Isabel A; Golsteijn, Laura; Hendriks, A Jan

2016-12-15

Marine plastic debris are found worldwide in oceans and coastal areas. They degrade only slowly and contain chemicals added during manufacture or absorbed from the seawater. Therefore, they can pose a long-lasting contaminant source and potentially transfer chemicals to marine organisms when ingested. In order to assess their risk, the contaminant concentration in the plastics needs to be estimated and differences understood. We collected from literature plastic water partition coefficients of various organic chemicals for seven plastic types: polydimethylsiloxane (PDMS), high-density, low-density and ultra-high molecular weight polyethylene (LDPE, HDPE, UHMWPE), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC). Most data was available for PDMS (1060) and LDPE (220), but much less for the remaining plastics (73). Where possible, regression models were developed and the partitioning was compared between the different plastic types. The partitioning of chemicals follows the order of LDPE≈HDPE≥PP>PVC≈PS. Data describing the impact of weathering are urgently needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Benzotriazole-type ultraviolet stabilizers and antioxidants in plastic marine debris and their new products.

PubMed

Rani, Manviri; Shim, Won Joon; Han, Gi Myung; Jang, Mi; Song, Young Kyoung; Hong, Sang Hee

2017-02-01

Ultraviolet stabilizers (UVSs) and antioxidants are the most widely used additives in plastics to enhance the lifetime of polymeric materials. There is growing interest in the roles of plastic marine debris and microplastics as source or vector of toxic substances to marine environment and organisms. However, there is limited information available on plastic associated chemicals, particularly additive chemicals. Therefore, to evaluate their extent of exposure from plastics to the marine environment, we determined UVSs and antioxidants in plastic debris (n=29) collected from beaches along with their corresponding new plastic products in markets (n=27) belonging to food, fisheries, and general use. Antioxidants were present at higher concentrations than UVSs in both plastic debris and new plastics, indicative of their high use over UVSs. Irganox 1076 and Irganox 1010 were more commonly used than other chemicals investigated. The irregular use with high concentration of additive chemicals was observed in short-term use plastic products. Except for Irganox 1076 and UV 326, most antioxidants and UVSs were relatively high in new plastics compared to corresponding plastic marine debris, implying their potential leaching or degradation during use or after disposal. The present study provides quantitative information about additive chemicals contained in plastic marine debris and their new products. These results could be useful for better understanding of environmental exposure to hazardous chemicals through plastic pollution. Copyright © 2016 Elsevier B.V. All rights reserved.

Phylogenetic Affiliation of Soil Bacteria That Degrade Aliphatic Polyesters Available Commercially as Biodegradable Plastics

PubMed Central

Suyama, Tetsushi; Tokiwa, Yutaka; Ouichanpagdee, Pornpimol; Kanagawa, Takahiro; Kamagata, Yoichi

1998-01-01

Thirty-nine morphologically different soil bacteria capable of degrading poly(β-hydroxyalkanoate), poly(ɛ-caprolactone), poly(hexamethylene carbonate), or poly(tetramethylene succinate) were isolated. Their phylogenetic positions were determined by 16S ribosomal DNA sequencing, and all of them fell into the classes Firmicutes and Proteobacteria. Determinations of substrate utilization revealed characteristic patterns of substrate specificities. PMID:9835597

Mapping Of Construction Waste Illegal Dumping Using Geographical Information System (GIS)

NASA Astrophysics Data System (ADS)

Zainun, Noor Yasmin; Rahman, Ismail Abdul; Azwana Rothman, Rosfazreen

2016-11-01

Illegal dumping of solid waste not only affecting the environment but also social life of communities, hence authorities should have an effective system to cater this problem. Malaysia is experiencing extensive physical developments and this has led to an increase of construction waste illegal dumping. However, due to the lack of proper data collection, the actual figure for construction waste illegal dumping in Malaysia are not available. This paper presents a mapping of construction waste illegal dumping in Kluang district, Johor using Geographic Information System (GIS) software. Information of the dumped waste such as coordinate, photos, types of material and quantity of waste were gathered manually through site observation for three months period. For quantifying the dumped waste, two methods were used which are the first method is based on shape of the waste (pyramids or squares) while the second method is based weighing approach. All information regarding the waste was assigned to the GIS for the mapping process. Results indicated a total of 12 types of construction waste which are concrete, tiles, wood, gypsum board, mixed construction waste, brick and concrete, bricks, sand, iron, glass, pavement and tiles, and concrete at 64 points locations of illegal dumping on construction waste in Kluang. These wastes were accounted to an estimated volume of 427.2636 m3. Hopefully, this established map will assist Kluang authority to improve their solid waste management system in Kluang.

Compaction and Plasticity Comparative Behaviour of Soft Clay Treated with Coarse and Fine Sizes of Ceramic Tiles

NASA Astrophysics Data System (ADS)

Al-Bared, Mohammed Ali Mohammed; Marto, Aminaton; Sati Hamonangan Harahap, Indra; Kasim, Fauziah

2018-03-01

Recycled blended ceramic tiles (RBT) is a waste material produced from ceramic tile factories and construction activities. RBT is found to be cost effective, sustainable, environmental-friendly and has the potential to be used as an additive in soft soil stabilization. Recent reports show that massive amounts of RBT are dumped into legal or illegal landfills every year consuming very large spaces and creating major environmental problems. On the other hand, dredged marine clay obtained from Nusajaya, Johor, Malaysia has weak physical and engineering characteristics to be considered as unsuitable soft soil that is usually excavated, dumped into landfills and replaced by stiff soil. Hence, this study investigates the suitability of possible uses of RBT to treat marine clay. Laboratory tests included Standard proctor tests and Atterberg limits tests. The plasticity of marine clay was evaluated by adding 10%, 20%, 30% and 40% of 0.3 mm RBT. In addition, the compaction behaviour of treated marine clay was compared by adding two different sizes (0.3 mm and 1.18 mm diameter) of RBT. For both coarse and fine sizes of RBT, 10%, 20%, 30% and 40% of the dry weight of the soft clay were added. The mixture of each combination was examined in order to evaluate the Maximum Dry Density (MDD) and the optimum moisture content (OMC) for the treated soft clay. MDD and OMC for soft untreated samples were 1.59 Mg/m3 and 22%, respectively. Treated samples with 10%, 20%, 30% and 40% of 0.30 mm size RBT resulted in a significant reduction of OMC ranged from 19 to 15% while MDD resulted in increment ranged from 1.69 to 1.77 Mg/m3. In addition, samples treated with 10%, 20%, 30% and 40% of 1.18 mm size RBT resulted in major reduction of OMC ranged from 15 to 13.5% while MDD increased effectively from 1.75 to 1.82 Mg/m3. For all mix designs of soft clay-RBT, MDD was gradually increasing and OMC was sharply reducing with further increments of both sizes of RBT.

Indoor air quality and health problems associated with damp floor coverings.

PubMed

Tuomainen, Anneli; Seuri, Markku; Sieppi, Anne

2004-04-01

To study the relationship between a high incidence of bronchial asthma among employees working in an office building and an indoor air problem related to the degradation of polyvinyl chloride (PVC) floor coverings in the building. The indoor air measurements and results of renovations are also described. Employees' symptoms were surveyed by a questionnaire, and the incidence of asthma was calculated from the medical records for 1997-2000. The quality of indoor air was assessed by microbial sampling and by investigation of the building for possible moisture damage. Indoor air was sampled for volatile organic compounds (VOCs) through Tenax adsorbent tubes. In situ volatile emission measurements from the concrete floor were performed via the field and laboratory emission cell (FLEC) method. In an office with approximately 150 employees, eight new cases of asthma were found in 4 years. In addition, the workers complained of respiratory, conjunctival and nasal symptoms. Emissions indicating the degradation of plastic floor coverings (e.g. 2-ethyl-1-hexanol, 1-butanol) were found in the indoor air and floor material samples. The plastic floor coverings, adhesives and the levelling layers were carefully removed from 12 rooms. The VOCs had diffused into the underlying concrete slabs. The concrete was warmed to remove the diffused VOCs from these areas. After the repairs the concentrations of the VOCs indicating the degradation of PVC, decreased, as did the prevalence of the employees' symptoms and several asthma patients' need for medication. The workers in the office building complained of several respiratory, conjunctival and dermal symptoms. The incidence of adult-onset asthma was approximately nine-times higher than that among Finns employed in similar work. The most probable single cause of the indoor air problem was the degradation of the plastic floor coverings.

Effect of glycerol and zinc oxide addition on antibacterial activity of biodegradable bioplastics from chitosan-kepok banana peel starch

NASA Astrophysics Data System (ADS)

Agustin, Y. E.; Padmawijaya, K. S.

2017-07-01

Bioplastic is a biopolymer plastic that can be degraded easily by microorganisms so it can be used as alternative replaced commercial plastic. This research aims to study the effects of additive (glycerol and zinc oxide) addition in the characteristic of antimicrobial activity and biodegradability bioplastic from chitosan and Kepok banana peel starch. In this research, bioplastics were synthesized by chitosan as the backbone and antimicrobial, Kepok banana peel starch as filler, glycerol as plasticizer, also ZnO as an amplifier. Bioplastics were characterized their antimicrobial activity using agar diffusion method (zone inhibition assay) and biodegradability test using microbe (EM4). The result showed the optimum composition of bioplastic is kitosan 4 - 30% starch - 5 mL glycerol - 5% ZnO gives the good antimicrobial activity towards gram positive and gram negative bacteria, and this bioplastic will be degraded within an hour and 12 min. Thus, this bioplastics may have potential to be use for food packaging by having biodegradable properties and also inhibit bacterial growth.

A Constitutive Model for Strain-Controlled Strength Degradation of Rockmasses (SDR)

NASA Astrophysics Data System (ADS)

Kalos, A.; Kavvadas, M.

2017-11-01

The paper describes a continuum, rate-independent, incremental plasticity constitutive model applicable in weak rocks and heavily fractured rockmasses, where mechanical behaviour is controlled by rockmass strength rather than structural features (discontinuities). The model describes rockmass structure by a generalised Hoek-Brown Structure Envelope (SE) in the stress space. Stress paths inside the SE are nonlinear and irreversible to better simulate behaviour at strains up to peak strength and under stress reversals. Stress paths on the SE have user-controlled volume dilatancy (gradually reducing to zero at large shear strains) and can model post-peak strain softening of brittle rockmasses via a structure degradation (damage) mechanism triggered by accumulated plastic shear strains. As the SE may strain harden with plastic strains, ductile behaviour can also be modelled. The model was implemented in the Finite Element Code Simulia ABAQUS and was applied in plane strain (2D) excavation of a cylindrical cavity (tunnel) to predict convergence-confinement curves. It is shown that small-strain nonlinearity, variable volume dilatancy and post-peak hardening/softening strongly affect the predicted curves, resulting in corresponding differences of lining pressures in real tunnel excavations.

40 CFR 227.12 - Insoluble wastes.

Code of Federal Regulations, 2010 CFR

2010-07-01

....12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.12... ocean environment may be generally approved for ocean dumping provided they are insoluble above the...

40 CFR 227.12 - Insoluble wastes.

Code of Federal Regulations, 2013 CFR

2013-07-01

....12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.12... ocean environment may be generally approved for ocean dumping provided they are insoluble above the...

40 CFR 227.12 - Insoluble wastes.

Code of Federal Regulations, 2011 CFR

2011-07-01

....12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.12... ocean environment may be generally approved for ocean dumping provided they are insoluble above the...

40 CFR 227.12 - Insoluble wastes.

Code of Federal Regulations, 2014 CFR

2014-07-01

....12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.12... ocean environment may be generally approved for ocean dumping provided they are insoluble above the...

Environmental impact assessment of sediment dumping in the southern Baltic Sea using meiofaunal indicators

NASA Astrophysics Data System (ADS)

Frenzel, Peter; Borrmann, Corinna; Lauenburg, Beate; Bohling, Björn; Bartholdy, Jan

2009-02-01

An experimental sediment dumping was carried out in the southern part of the Mecklenburg Bight in June 2001. Foraminiferans and ostracods from superficial sandy sediment were studied in a time series from before dumping until March 2004 in order to assess changes in associations and recolonization patterns of both groups. Additionally, an area sampling covering the dumping site and its surroundings from 15.5 to 20.7 m water depth made it possible to compare associations inside and outside the dumping area as well as the water depth dependent distribution of foraminiferans and ostracods. Salinity values vary within the high alpha-mesohaline and low polyhaline range. The dominating species are Ammotium cassis (Foraminifera) and Sarsicytheridea bradii (Ostracoda). The diversity is low (Fisher alpha index from 0.4 to 3.2 for foraminiferans and 1.0 to 2.5 for ostracods), but higher within the dumping site samples. These higher values are explainable by input of allochthonous tests and valves representing additional species. After the sediment dumping it took two and a half years to re-establish the total foraminiferan association and the total foraminifer/ostracod ratio within the dumping site. Total foraminiferan abundance increases remarkably with water depth (mean 83 tests in 100 ml) driven by higher nutrient availability and more suitable salinity and temperature values within the zone of the oscillating halocline. The distribution of shallow water species such as Cribroelphidium excavatum, Eucythere argus and Hirschmannia viridis, within the transient water layer A. cassis, Nodulina dentaliniformis, S. bradii and Palmoconcha laevata and below Eggerella scabra indicate the depth position of the halocline. Water depth and sediment dumping influence are the main driving factors for the distribution of foraminifer and ostracod associations within the study area. However, a significant sedimentological difference between samples inside and outside the dumping area is not recognizable.

Q&A: Brenda Keneghan: The polymer conservator

NASA Astrophysics Data System (ADS)

Gibney, Elizabeth

2016-08-01

For many, plastic is a dirty word -- a pollutant that can't degrade soon enough. But for polymer scientist Brenda Keneghan, it's a precious material that looms large in design history. A conservator at the Victoria and Albert Museum (V&A) in London, Keneghan spends her days saving plastic items from furniture to toys from the ravages of time. Here she talks about the war against the warping, yellowing, crumbling and stickiness that plague polymers.

50 CFR 85.11 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... increase the value of usefulness of existing property. Dump station. A facility specifically designed to receive sewage from portable toilets carried on vessels. Dump stations do not include lavatories or... pumpout and dump stations. Eligible applicant. An agency of a State designated by the Governor. Equitable...

40 CFR 227.5 - Prohibited materials.

Code of Federal Regulations, 2012 CFR

2012-07-01

....5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.5 Prohibited materials. The ocean dumping of the following materials will not be approved by EPA or the Corps...

40 CFR 227.17 - Basis for determination.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 227.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed Dumping on Esthetic, Recreational and Economic Values § 227.17 Basis for determination. (a) The impact of...

ANNUAL REPORT TO CONGRESS ON OCEAN DUMPING

EPA Science Inventory

This Report to Congress covers calendar years 1987 through Fiscal Year 1990 Activities covered include EPA’s implementation of the Marine Protection, Research, and Sanctuaries Act (MPRSA) and the 1988 amendment, the Ocean Dumping Ban Act (ODBA). ODBA makes the dumping of mu...

Particle damping applied research on mining dump truck vibration control

NASA Astrophysics Data System (ADS)

Song, Liming; Xiao, Wangqiang; Guo, Haiquan; Yang, Zhe; Li, Zeguang

2018-05-01

Vehicle vibration characteristics has become an important evaluation indexes of mining dump truck. In this paper, based on particle damping technology, mining dump truck vibration control was studied by combining the theoretical simulation with actual testing, particle damping technology was successfully used in mining dump truck cab vibration control. Through testing results analysis, with a particle damper, cab vibration was reduced obviously, the methods and basis were provided for vehicle vibration control research and particle damping technology application.

Resilience Analysis of Face Slopes and Internal Dumps and Causes of their Instability at “Mugunsky” Opencast Coal Mine

NASA Astrophysics Data System (ADS)

Zagibalov, A. V.; Okhotin, A. L.; Volokhov, A. V.

2017-10-01

The paper deals with the problems of initiation and consequences of landslide processes registered in the internal dumps at Mugunsky lignite opencast mine. Water cutting at the internal dump base, availability of clay rocks in the dump bottom, and the bottom incline towards the working face are revealed to be the sources of the landslide process. Some measures are recommended to prevent deformation processes that are possible to take place in the run of mine development.

A summary of the test procedures and operational details of an ocean dumping pollution monitoring experiment conducted 7 October 1976

NASA Technical Reports Server (NTRS)

Hypes, W. D.; Wallace, J. W.; Gurganus, E. A.

1977-01-01

A remote sensor experiment was conducted at a sewage sludge dump site off the Delaware/Maryland coast. Two aircraft serving as remote sensor platforms flew over the dump site during a sludge dump. One aircraft carried a multispectral scanner and the other aircraft carried a rapid scanning spectrometer. Data from sea-truth stations were collected concurrent with overpasses of the aircraft. All sensors were operational and produced good digital data.

Bioaccumulation of organochlorines in crows from an indian open waste dumping site: evidence for direct transfer of dioxin-like congeners from the contaminated soil.

PubMed

Watanabe, Michio X; Iwata, Hisato; Watanabe, Mafumi; Tanabe, Shinsuke; Subramanian, Annamalai; Yoneda, Kumiko; Hashimoto, Takuma

2005-06-15

To assess the significance of waste dumping sites as a source of chemical contamination to ecosystems, we analyzed the residue levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and other organochlorines in the breast muscle of crows from a dumping site in the south of Chennai city, South India. Crows from the dumping site contained significantly higher total TEQs (60 +/- 27 pg/g lipid wt) than those from the reference sites (26 +/- 18 pg/g lipid wt). Especially, certain dioxin-like coplanar PCB congeners (Co-PCBs), such as CB-77 and CB-105, whose source is commercial PCBs,were significantly higher in crows from the dumping site than those from the reference sites. Profiles of PCDDs/DFs and Co-PCBs in crows from the dumping site were similar to those of soil at the same site, which was confirmed by principal component analysis. Furthermore, significant positive correlations were obtained between the congener-specific bioconcentration factors (BCFs) of PCDDs/DFs estimated from concentrations in crows and soil from the dumping site and the theoretical BCFs calculated from water-particle and lipid-water partitioning coefficients. On the other hand, the estimated BCFs had significant negative correlations with the molecular weight of PCDDs/DFs, indicating that molecular size limits their bioaccumulation. These results suggest that dioxin-like congeners in the soil of the dumping site were transferred directly to the crows through the ingestion of on-site garbage contaminated with soil, rather than through trophic transfer in the ecosystem. The present study provides insight into the ecological impacts of dumping sites.

Unraveling the Primary Isomerization Dynamics in Cyanobacterial Phytochrome Cph1 with Multi-pulse Manipulations.

PubMed

Kim, Peter W; Rockwell, Nathan C; Freer, Lucy H; Chang, Che-Wei; Martin, Shelley S; Lagarias, J Clark; Larsen, Delmar S

2013-07-20

The ultrafast mechanisms underlying the initial photoisomerization (P r → Lumi-R) in the forward reaction of the cyanobacterial photoreceptor Cph1 were explored with multipulse pump-dump-probe transient spectroscopy. A recently postulated multi-population model was used to fit the transient pump-dump-probe and dump-induced depletion signals. We observed dump-induced depletion of the Lumi-R photoproduct, demonstrating that photoisomerization occurs via evolution on both the excited- and ground-state electronic surfaces. Excited-state equilibrium was not observed, as shown via the absence of a dump-induced excited-state "Le Châtelier redistribution" of excited-state populations. The importance of incorporating the inhomogeneous dynamics of Cph1 in interpreting measured transient data is discussed.

Unraveling the Primary Isomerization Dynamics in Cyanobacterial Phytochrome Cph1 with Multi-pulse Manipulations

PubMed Central

Kim, Peter W.; Rockwell, Nathan C.; Freer, Lucy H.; Chang, Che-Wei; Martin, Shelley S.; Lagarias, J. Clark; Larsen, Delmar S.

2013-01-01

The ultrafast mechanisms underlying the initial photoisomerization (Pr → Lumi-R) in the forward reaction of the cyanobacterial photoreceptor Cph1 were explored with multipulse pump-dump-probe transient spectroscopy. A recently postulated multi-population model was used to fit the transient pump-dump-probe and dump-induced depletion signals. We observed dump-induced depletion of the Lumi-R photoproduct, demonstrating that photoisomerization occurs via evolution on both the excited- and ground-state electronic surfaces. Excited-state equilibrium was not observed, as shown via the absence of a dump-induced excited-state “Le Châtelier redistribution” of excited-state populations. The importance of incorporating the inhomogeneous dynamics of Cph1 in interpreting measured transient data is discussed. PMID:24143267

50 CFR 85.30 - Grant selection criteria.

Code of Federal Regulations, 2011 CFR

2011-10-01

... constructing and renovating pumpout and dump stations without an approved plan; (c) In coastal States, proposals for constructing and renovating pumpout and dump stations in accordance with a coastal State's... constructing and renovating pumpout and dump stations in accordance with an inland State's plan; (d) Proposals...

Which Disc Player for Education? A Comparative Evaluation.

ERIC Educational Resources Information Center

Leveridge, Leo L.; Lyons, David S.

1983-01-01

Advantages and disadvantages of videodisc players using digital program dumps are discussed. Indicates that, although digital dumps on videodiscs can be used to deliver interactive audiovisual programs about as effectively as external computer programs, disadvantages greatly outweigh advantages. Thus, digital program dumps recorded on videodiscs…

40 CFR 223.3 - Preliminary determination; notice.

Code of Federal Regulations, 2010 CFR

2010-07-01

....3 Section 223.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Procedures for Revision, Revocation or Limitation of Ocean Dumping Permits Under Section 104(d...

40 CFR 227.5 - Prohibited materials.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 227.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.5 Prohibited materials. The ocean dumping of the following materials will not be approved by EPA or the Corps...

40 CFR 227.4 - Criteria for evaluating environmental impact.

Code of Federal Regulations, 2011 CFR

2011-07-01

... impact. 227.4 Section 227.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental... impact prohibitions, limits, and conditions for the dumping of materials into ocean waters. If the...

40 CFR 227.5 - Prohibited materials.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 227.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.5 Prohibited materials. The ocean dumping of the following materials will not be approved by EPA or the Corps...

40 CFR 223.3 - Preliminary determination; notice.

Code of Federal Regulations, 2013 CFR

2013-07-01

....3 Section 223.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Procedures for Revision, Revocation or Limitation of Ocean Dumping Permits Under Section 104(d...

40 CFR 223.3 - Preliminary determination; notice.

Code of Federal Regulations, 2011 CFR

2011-07-01

....3 Section 223.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Procedures for Revision, Revocation or Limitation of Ocean Dumping Permits Under Section 104(d...

40 CFR 223.3 - Preliminary determination; notice.

Code of Federal Regulations, 2012 CFR

2012-07-01

....3 Section 223.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Procedures for Revision, Revocation or Limitation of Ocean Dumping Permits Under Section 104(d...

40 CFR 227.4 - Criteria for evaluating environmental impact.

Code of Federal Regulations, 2013 CFR

2013-07-01

... impact. 227.4 Section 227.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental... impact prohibitions, limits, and conditions for the dumping of materials into ocean waters. If the...

40 CFR 223.3 - Preliminary determination; notice.

Code of Federal Regulations, 2014 CFR

2014-07-01

....3 Section 223.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CONTENTS OF PERMITS; REVISION, REVOCATION OR LIMITATION OF OCEAN DUMPING PERMITS UNDER SECTION 104(d) OF THE ACT Procedures for Revision, Revocation or Limitation of Ocean Dumping Permits Under Section 104(d...

40 CFR 227.5 - Prohibited materials.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 227.5 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.5 Prohibited materials. The ocean dumping of the following materials will not be approved by EPA or the Corps...

40 CFR 227.17 - Basis for determination.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Section 227.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed Dumping on Esthetic, Recreational and Economic Values § 227.17 Basis for determination. (a) The impact of...

40 CFR 227.17 - Basis for determination.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Section 227.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed Dumping on Esthetic, Recreational and Economic Values § 227.17 Basis for determination. (a) The impact of...

40 CFR 227.4 - Criteria for evaluating environmental impact.

Code of Federal Regulations, 2012 CFR

2012-07-01

... impact. 227.4 Section 227.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental... impact prohibitions, limits, and conditions for the dumping of materials into ocean waters. If the...

40 CFR 227.4 - Criteria for evaluating environmental impact.

Code of Federal Regulations, 2014 CFR

2014-07-01

... impact. 227.4 Section 227.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental... impact prohibitions, limits, and conditions for the dumping of materials into ocean waters. If the...

40 CFR 227.17 - Basis for determination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Section 227.17 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed Dumping on Esthetic, Recreational and Economic Values § 227.17 Basis for determination. (a) The impact of...

Contamination of water due to major industries and open refuse dumping in the steel city of Orissa--a case study.

PubMed

Mishra, P C; Behera, P C; Patel, R K

2005-04-01

Contamination of ground water is common in the areas surrounded by industrial refuse dumping sites and the probability of contamination is more where dumping is done in low lying areas and the rate of percolation through the soil is high. In order to assess the ground water pollution by leachate around the refuse dumping site, eighteen wells were selected for study. Few wells are nearer to the dumps, few are far away and others are in between. Also an attempt has been made to evaluate the effect of industrial effluents on the ground and surface water due to Integrated Rourkela Steel Plant and other major industries. From the analytical data of physico-chemical parameters, it is indicated that the river water is contaminated mainly due to the industrial and municipal effluents and the ground water of some of the analyzed areas is contaminated due to municipal and industrial solid waste dumping.

Study of Internal Dump Stability of Dudhichua Open Cast Project, Northern Coalfields Limited, India

NASA Astrophysics Data System (ADS)

Sengupta, S.; Roy, I.

2015-04-01

Dudhichua Open Cast Project is one of the prestigious projects of Northern Coalfields Limited, India; with total mineable coal reserves of approximately 400 million tonnes and corresponding 1,700 million m3 volume of waste rock i.e. overburden material. Accommodating this waste dump masses in the limited space of the de-coaled portion of the quarry is considered as one of the major challenges to the mine operators. It has been reported that this mine is facing frequent slope failures of waste rock dumps which is of great concern to the mine management in view of unsafe working condition. To tackle the above problem, a detailed investigation was carried out to propose a stable dump profile which will cater to the land economics and safety aspects of the mine. A detailed investigation along with recommendation of optimum design for dragline dump profile along with shovel-dumper-dump profile is presented in this paper.

Development of Methods of Characterizing Coal in Its Plastic State

NASA Technical Reports Server (NTRS)

Lloyd, W. G.

1978-01-01

Coal in its plastic state (typically 400-460 C) was examined by the isothermal Gieseler plastometry of seven selected coals of widely varying plastic properties. Kinetic models were proposed for the isothermal plastometric curves. Plastic behavior was compared with a variety of laboratory analyses and characterizations of these coals, including classical coal analysis; mineral analysis; microstructural analysis (extractable fractions, surface area measurement, and petrographic analysis); and thermal analysis (thermogravimetric analysis, thermomechanical analysis, and differential scanning calorimetry). The phenomenon of a sharp, large, poorly reproducible exotherm in the differential scanning calorimetric analysis of coking coals was examined. Several coal extrudates show mineral distribution, organic maceral composition and overall calorific value to be little affected by 800 F extrusion. Volatile matter and plastic properties are moderately reduced, and the network structure (as gauged by extractables) appears to be slightly degraded in the extrusion process.

Creating Methane from Plastic: Recycling at a Lunar Outpost

NASA Technical Reports Server (NTRS)

Santiago-Maldonado, Edgardo; Captain, Janine; Devor, Robert; Gleaton, Jeremy

2010-01-01

The high cost of re-supply from Earth demands resources to be utilized to the fullest extent for exploration missions. The ability to refuel on the lunar surface would reduce the vehicle mass during launch and provide excess payload capability. Recycling is a key technology that maximizes the available resources by converting waste products into useful commodities. One example of this is to convert crew member waste such as plastic packaging, food scraps, and human waste into fuel. This process thermally degrades plastic in the presence of oxygen producing CO2 and CO. The CO2 and CO are then reacted with hydrogen over catalyst (Sabatier reaction) producing methane. An end-to-end laboratory-scale system has been designed and built to produce methane from plastic, in this case polyethylene. This first generation system yields 12-16% CH4 by weight of plastic used.

Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments.

PubMed

Nauendorf, Alice; Krause, Stefan; Bigalke, Nikolaus K; Gorb, Elena V; Gorb, Stanislav N; Haeckel, Matthias; Wahl, Martin; Treude, Tina

2016-02-15

To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98 days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Non-targeted multi-component analytical surveillance of plastic food contact materials: Identification of substances not included in EU positive lists and their risk assessment.

PubMed

Skjevrak, Ingun; Brede, Cato; Steffensen, Inger-Lise; Mikalsen, Arne; Alexander, Jan; Fjeldal, Per; Herikstad, Hallgeir

2005-10-01

A procedure used by the Norwegian Food Safety Authority for surveillance of contaminants from plastic food contact materials (polyolefin drinking bottles, water boilers, polyamide cooking utensils and plastic multi-layer materials) is described. It is based on gas chromatographic-mass spectrometric (GC/MS) analysis of food simulants exposed to plastic materials. Most migrants were substances not-intentionally added to the plastic (degradation products, impurities) or originated from non-plastic components, such as printing inks, adhesives, not-listed additives, solvents and coatings. Hence, the majority of the identified migrants were regulated by the general statements in the EU Framework Regulation, which neither specify limits nor requirements regarding risk assessment, rather than by specific migration controls. Risk assessment has been carried out for selected non-authorized substances. The analysis and the management of these substances and materials with respect to safety represents a challenge to the food authorities.

The use of potassium hydroxide (KOH) solution as a suitable approach to isolate plastics ingested by marine organisms.

PubMed

Kühn, Susanne; van Werven, Bernike; van Oyen, Albert; Meijboom, André; Bravo Rebolledo, Elisa L; van Franeker, Jan A

2017-02-15

In studies of plastic ingestion by marine wildlife, visual separation of plastic particles from gastrointestinal tracts or their dietary content can be challenging. Earlier studies have used solutions to dissolve organic materials leaving synthetic particles unaffected. However, insufficient tests have been conducted to ensure that different categories of consumer products partly degraded in the environment and/or in gastrointestinal tracts were not affected. In this study 63 synthetic materials and 11 other dietary items and non-plastic marine debris were tested. Irrespective of shape or preceding environmental history, most polymers resisted potassium hydroxide (KOH) solution, with the exceptions of cellulose acetate from cigarette filters, some biodegradable plastics and a single polyethylene sheet. Exposure of hard diet components and other marine debris showed variable results. In conclusion, the results confirm that usage of KOH solutions can be a useful approach in general quantitative studies of plastic ingestion by marine wildlife. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Pseudomonas aeruginosa biofilm formation and UV/irradiation exposure change surface and chemical structures of Pre-Production Resin Pellets

NASA Astrophysics Data System (ADS)

Stam, C. N.; Neal, A.; Park, S.; Mielke, R.; Tsapin, A. I.; Bhartia, R.; Salas, E.; Hug, W.; Behar, A. E.; Nadeau, J. L.

2011-12-01

Microbial interactions with synthetic polymers in open ocean is poorly understood. Plastics are a major and persistent contaminant of ocean waters. Many of these plastics are contaminated with toxic and synthetic chemicals that persist in the environment with minimal degradation. The purpose of this study is to look at the effects that microbial biofilm communities have on both surface and chemical structures of pre-production resin pellets (PRPs). Pseudomonas aeruignosa was grown with PRPs under multiple growth and nutrient conditions. These conditions were combined with varying lengths of UV exposures common to ocean environments. Material degradation of the PRPs and the changing surface and chemical structures of these synthetic polymers was evaluated using a combination of Fourier transform infrared spectroscopy, environmental scanning electron microscopy, scanning transmission electron microscopy, X-ray microtomography, and ArcGIS mapping. This study correlates with previous studies conducted on environmental PRP's , collected on the 2009 Project Kaisei expedition in the Subtropical Convergence Zone of the North Pacific Gyre. Further studies are needed to develop a full understanding of degradation rates of synthetic polymers in oceanic environments.

Use of phytoproductivity data in the choice of native plant species to restore a degraded coal mining site amended with a stabilized industrial organic sludge.

PubMed

Chiochetta, Claudete G; Toumi, Hela; Böhm, Renata F S; Engel, Fernanda; Poyer-Radetski, Gabriel; Rörig, Leonardo R; Adani, Fabrizio; Radetski, Claudemir M

2017-11-01

Coal mining-related activities result in a degraded landscape and sites associated with large amounts of dumped waste material. The arid soil resulting from acid mine drainage affects terrestrial and aquatic ecosystems, and thus, site remediation programs must be implemented to mitigate this sequential deleterious processes. A low-cost alternative material to counterbalance the affected physico-chemical-microbiological aspects of the degraded soil is the amendment with low contaminated and stabilized industrial organic sludge. The content of nutrients P and N, together with stabilized organic matter, makes this material an excellent fertilizer and soil conditioner, fostering biota colonization and succession in the degraded site. However, choice of native plant species to restore a degraded site must be guided by some minimal criteria, such as plant survival/adaptation and plant biomass productivity. Thus, in this 3-month study under environmental conditions, phytoproductivity tests with five native plant species (Surinam cherry Eugenia uniflora L., C. myrianthum-Citharexylum myrianthum, Inga-Inga spp., Brazilian peppertree Schinus terebinthifolius, and Sour cherry Prunus cerasus) were performed to assess these criteria, and additional biochemical parameters were measured in plant tissues (i.e., protein content and peroxidase activity) exposed to different soil/sludge mixture proportions. The results show that three native plants were more adequate to restore vegetation on degraded sites: Surinam cherry, C. myrianthum, and Brazilian peppertree. Thus, this study demonstrates that phytoproductivity tests associated with biochemical endpoint measurements can help in the choice of native plant species, as well as aiding in the choice of the most appropriate soil/stabilized sludge proportion in order to optimize biomass production.

40 CFR 227.20 - Basis for determination.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 227.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed... subpart E will be based on the impact of the proposed dumping on specific uses of the ocean rather than on...

Molecular Characterization of the Bacterial Community in Biofilms for Degradation of Poly(3-Hydroxybutyrate-co-3-Hydroxyhexanoate) Films in Seawater

PubMed Central

Morohoshi, Tomohiro; Ogata, Kento; Okura, Tetsuo; Sato, Shunsuke

2018-01-01

Microplastics are fragmented pieces of plastic in marine environments, and have become a serious environmental issue. However, the dynamics of the biodegradation of plastic in marine environments have not yet been elucidated in detail. Polyhydroxyalkanoates (PHAs) are biodegradable polymers that are synthesized by a wide range of microorganisms. One of the PHA derivatives, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) has flexible material properties and a low melting temperature. After an incubation in seawater samples, a significant amount of biofilms were observed on the surfaces of PHBH films, and some PHBH films were mostly or partially degraded. In the biofilms that formed on the surfaces of unbroken PHBH films, the most dominant operational taxonomic units (OTUs) showed high similarity with the genus Glaciecola in the family Alteromonadaceae. On the other hand, the dominant OTUs in the biofilms that formed on the surfaces of broken PHBH films were assigned to the families Rhodobacteraceae, Rhodospirillaceae, and Oceanospirillaceae, and the genus Glaciecola mostly disappeared. The bacterial community in the biofilms on PHBH films was assumed to have dynamically changed according to the progression of degradation. Approximately 50 colonies were isolated from the biofilm samples that formed on the PHBH films and their PHBH-degrading activities were assessed. Two out of three PHBH-degrading isolates showed high similarities to Glaciecola lipolytica and Aestuariibacter halophilus in the family Alteromonadaceae. These results suggest that bacterial strains belonging to the family Alteromonadaceae function as the principal PHBH-degrading bacteria in these biofilms. PMID:29386425

Molecular Characterization of the Bacterial Community in Biofilms for Degradation of Poly(3-Hydroxybutyrate-co-3-Hydroxyhexanoate) Films in Seawater.

PubMed

Morohoshi, Tomohiro; Ogata, Kento; Okura, Tetsuo; Sato, Shunsuke

2018-03-29

Microplastics are fragmented pieces of plastic in marine environments, and have become a serious environmental issue. However, the dynamics of the biodegradation of plastic in marine environments have not yet been elucidated in detail. Polyhydroxyalkanoates (PHAs) are biodegradable polymers that are synthesized by a wide range of microorganisms. One of the PHA derivatives, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) has flexible material properties and a low melting temperature. After an incubation in seawater samples, a significant amount of biofilms were observed on the surfaces of PHBH films, and some PHBH films were mostly or partially degraded. In the biofilms that formed on the surfaces of unbroken PHBH films, the most dominant operational taxonomic units (OTUs) showed high similarity with the genus Glaciecola in the family Alteromonadaceae. On the other hand, the dominant OTUs in the biofilms that formed on the surfaces of broken PHBH films were assigned to the families Rhodobacteraceae, Rhodospirillaceae, and Oceanospirillaceae, and the genus Glaciecola mostly disappeared. The bacterial community in the biofilms on PHBH films was assumed to have dynamically changed according to the progression of degradation. Approximately 50 colonies were isolated from the biofilm samples that formed on the PHBH films and their PHBH-degrading activities were assessed. Two out of three PHBH-degrading isolates showed high similarities to Glaciecola lipolytica and Aestuariibacter halophilus in the family Alteromonadaceae. These results suggest that bacterial strains belonging to the family Alteromonadaceae function as the principal PHBH-degrading bacteria in these biofilms.

Bacteria-mediated bisphenol A degradation.

PubMed

Zhang, Weiwei; Yin, Kun; Chen, Lingxin

2013-07-01

Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

Toxicity of leachate from weathering plastics: An exploratory screening study with Nitocra spinipes.

PubMed

Bejgarn, Sofia; MacLeod, Matthew; Bogdal, Christian; Breitholtz, Magnus

2015-08-01

Between 60% and 80% of all marine litter is plastic. Leachate from plastics has previously been shown to cause acute toxicity in the freshwater species Daphnia magna. Here, we present an initial screening of the marine environmental hazard properties of leachates from weathering plastics to the marine harpacticoid copepod [Crustacea] Nitocra spinipes. Twenty-one plastic products made of different polymeric materials were leached and irradiated with artificial sunlight. Eight of the twenty-one plastics (38%) produced leachates that caused acute toxicity. Differences in toxicity were seen for different plastic products, and depending on the duration of irradiation. There was no consistent trend in how toxicity of leachate from plastics changed as a function of irradiation time. Leachate from four plastics became significantly more toxic after irradiation, two became significantly less toxic and two did not change significantly. Analysis of leachates from polyvinyl chloride (PVC) by liquid chromatography coupled to a full-scan high-resolution mass spectrometer showed that the leachates were a mixture of substances, but did not show evidence of degradation of the polymer backbone. This screening study demonstrates that leachates from different plastics differ in toxicity to N. spinipes and that the toxicity varies under simulated weathering. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Lower Length Scale Model Development for Embrittlement of Reactor Presure Vessel Steel

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

Zhang, Yongfeng; Schwen, Daniel; Chakraborty, Pritam

2016-09-01

This report summarizes the lower-length-scale effort during FY 2016 in developing mesoscale capabilities for microstructure evolution, plasticity and fracture in reactor pressure vessel steels. During operation, reactor pressure vessels are subject to hardening and embrittlement caused by irradiation induced defect accumulation and irradiation enhanced solute precipitation. Both defect production and solute precipitation start from the atomic scale, and manifest their eventual effects as degradation in engineering scale properties. To predict the property degradation, multiscale modeling and simulation are needed to deal with the microstructure evolution, and to link the microstructure feature to material properties. In this report, the development ofmore » mesoscale capabilities for defect accumulation and solute precipitation are summarized. A crystal plasticity model to capture defect-dislocation interaction and a damage model for cleavage micro-crack propagation is also provided.« less

Assessment of carbon sequestration potential of revegetated coal mine overburden dumps: A chronosequence study from dry tropical climate.

PubMed

Ahirwal, Jitendra; Maiti, Subodh Kumar

2017-10-01

Development of secondary forest as post-mining land use in the surface coal mining degraded sites is of high research interest due to its potential to sequester atmospheric carbon (C). The objectives of this study were to assess the improvement in mine soil quality and C sequestration potential of the post-mining reclaimed land with time. Hence, this study was conducted in reclaimed chronosequence sites (young, intermediate and old) of a large open cast coal project (Central Coal Fields Limited, Jharkhand, India) and results were compared to a reference forest site (Sal forest, Shorea robusta). Mine soil quality was assessed in terms of accretion of soil organic carbon (SOC), available nitrogen (N) and soil CO 2 flux along with the age of revegetation. After 14 years of revegetation, SOC and N concentrations increased three and five-fold, respectively and found equivalent to the reference site. Accretion of SOC stock was estimated to be 1.9 Mg C ha -1 year -1 . Total ecosystem C sequestered after 2-14 years of revegetation increased from 8 Mg C ha -1 to 90 Mg C ha -1 (30-333 Mg CO 2 ha -1 ) with an average rate of 6.4 Mg C ha -1 year -1 . Above ground biomass contributes maximum C sequestrate (50%) in revegetated site. CO 2 flux increased with age of revegetation and found 11, 33 and 42 Mg CO 2 ha -1 year -1 in younger, intermediate and older dumps, respectively. Soil respiration in revegetated site is more influenced by the temperature than soil moisture. Results of the study also showed that trees like, Dalbergia sissoo and Heterophragma adenophyllum should be preferred for revegetation of mine degraded sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

30 CFR 56.9301 - Dump site restraints.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Dump site restraints. 56.9301 Section 56.9301 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... § 56.9301 Dump site restraints. Berms, bumper blocks, safety hooks, or similar impeding devices shall...

30 CFR 56.9301 - Dump site restraints.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Dump site restraints. 56.9301 Section 56.9301 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... § 56.9301 Dump site restraints. Berms, bumper blocks, safety hooks, or similar impeding devices shall...

30 CFR 57.9301 - Dump site restraints.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Dump site restraints. 57.9301 Section 57.9301 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... § 57.9301 Dump site restraints. Berms, bumper blocks, safety hooks, or similar impeding devices shall...

7 CFR 58.212 - Hopper or dump room.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Hopper or dump room. 58.212 Section 58.212 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....212 Hopper or dump room. A separate room shall be provided for the transfer of bulk dry dairy products...

40 CFR 227.20 - Basis for determination.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 227.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed... subpart E will be based on the impact of the proposed dumping on specific uses of the ocean rather than on...

40 CFR 227.20 - Basis for determination.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Section 227.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed... subpart E will be based on the impact of the proposed dumping on specific uses of the ocean rather than on...

40 CFR 227.20 - Basis for determination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Section 227.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed... subpart E will be based on the impact of the proposed dumping on specific uses of the ocean rather than on...

40 CFR 227.20 - Basis for determination.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Section 227.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Impact of the Proposed... subpart E will be based on the impact of the proposed dumping on specific uses of the ocean rather than on...

Ultrashort-pulse-train pump and dump excitation of a diatomic molecule

NASA Astrophysics Data System (ADS)

de Araujo, Luís E. E.

2010-09-01

An excitation scheme is proposed for transferring population between ground-vibrational levels of a molecule. The transfer is accomplished by pumping and dumping population with a pair of coherent ultrashort-pulse trains via a stationary state. By mismatching the teeth of the frequency combs associated with the pulse trains to the vibrational levels, high selectivity in the excitation, along with high transfer efficiency, is predicted. The pump-dump scheme does not suffer from spontaneous emission losses, it is insensitive to the pump-dump-train delay, and it requires only basic pulse shaping.

Ultrashort-pulse-train pump and dump excitation of a diatomic molecule

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

Araujo, Luis E. E. de

An excitation scheme is proposed for transferring population between ground-vibrational levels of a molecule. The transfer is accomplished by pumping and dumping population with a pair of coherent ultrashort-pulse trains via a stationary state. By mismatching the teeth of the frequency combs associated with the pulse trains to the vibrational levels, high selectivity in the excitation, along with high transfer efficiency, is predicted. The pump-dump scheme does not suffer from spontaneous emission losses, it is insensitive to the pump-dump-train delay, and it requires only basic pulse shaping.

Monitoring the growth or decline of vegetation on mine dumps

NASA Technical Reports Server (NTRS)

Gilbertson, B. P. (Principal Investigator)

1975-01-01

The author has identified the following signficant results. It was established that particular mine dumps throughout the entire test area can be detected and identified. It was also established that patterns of vegetative growth on the mine dumps can be recognized from a simple visual analysis of photographic images. Because vegetation tends to occur in patches on many mine dumps, it is unsatisfactory to classify complete dumps into categories of percentage vegetative cover. A more desirable approach is to classify the patches of vegetation themselves. The coarse resolution of conventional densitometers restricts the accuracy of this procedure, and consequently a direct analysis of ERTS CCT's is preferred. A set of computer programs was written to perform the data reading and manipulating functions required for basic CCT analysis.

Chevron beam dump for ITER edge Thomson scattering system.

PubMed

Yatsuka, E; Hatae, T; Vayakis, G; Bassan, M; Itami, K

2013-10-01

This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due to nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.

Determination of technological parameters in strip mining by time-of-flight and image processing

NASA Astrophysics Data System (ADS)

Elandaloussi, Frank; Mueller, B.; Osten, Wolfgang

1999-09-01

The conveying and dumping of earth masses lying over the coal seam in lignite surface mining is done usually by overburden conveyor bridges. The overburden, obtained from connected excavators, is transported over the bridge construction using a conveyor belt system and poured into one front dump and three surface dumps. The shaping of the dump growth is of great importance both to guaranty the stability of the masses dumped to earth stocks as well as the whole construction and to prepare the area for re-cultivation. This article describes three measurement systems: one to determine the impact point of the dumped earth masses, one to determine the shape of the entire mining process and the other a sensor for the loading of the conveyor belt. For the first measurement system, a real-time video system has been designed, set-up and installed that is capable to determine the impact point of all three dumps simultaneously. The second measurement system is a connection of 5 special designed laser distance measuring instruments, that are able to measure the shape of the mining process under unfavorable environmental conditions like dust, high temperature changes, heavy shocks etc. The third sensor is designed for monitoring the transportation of the masses via the conveyor belt system.

Investigation of mine and industry dumps in the FRG in relation to a possible release of natural radioactive elements.

PubMed

Schmitz, J

1985-10-01

More than 350 dumps of mines and industries in two federal states of the FRG were recorded, measured radiometrically, evaluated, and some of them sampled. Most of the mine dumps belonged to old and smaller residues from lead/zinc and iron ore mining, while the largest depositions contain tailings of modern ore beneficiation or flyash disposal. All mine dumps from uranium exploration in Baden-Württemberg and Bavaria were investigated. The highest doses, up to 100 mSv/a, were found on the piles of the uranium exploration. These depositions, which are supervised and licensed, are followed, in terms of surface dose, by the old uncontrolled mine dumps of silver/cobalt mining with doses up to 20 mSv/a. The numerous porphyry and granite quarries show doses between 1 and 2 mSv/a, as do flyash and slag dumps. The lowest doses were found on the dumps of the hydrothermal Pb/Zn and iron ore deposits, while the slag piles of iron ore processing showed higher thorium values. Assays for Ra-226 and Pb-210 of the materials deposited confirmed the radiometric results. Analyses of seepage waters and gallery waters showed only very few values exceeding the derived drinking water concentrations.

Reconstruction of the inner structure of small scale mining waste dumps by combining GPR and ERTdata.

NASA Astrophysics Data System (ADS)

Kniess, Rudolf; Martin, Tina

2015-04-01

Two abandoned small waste dumps in the west of the Harz mountains (Germany) were analysed using ground penetrating radar (GPR) and electrical resistivity tomography (ERT). Aim of the project (ROBEHA, funded by the German Federal Ministry of Education and Research (033R105)) is the assessment of the recycling potential of the mining residues taking into account environmental risks of reworking the dump site. One task of the geophysical prospection is the investigation of the inner structure of the mining dump. This is important for the estimation of the approximate volume of potentially reusable mining deposits within the waste dump. The two investigated dump sites are different in age and therefore differ in their structure. The older residues (< 1930) consist of ore processing waste from density separation (stamp mill sand). The younger dump site descends from comprises slag dump waste. The layer of fine grained residues at the first dump site is less than 6 m thick and the slag layer is less than 2 m thick. Both sites are partially overlain by forest or grassland vegetation and characterized by topographical irregularities. Due to the inhomogeneity of the sites we applied electrical resistivity tomography (ERT) and ground penetrating radar (GPR) for detailed investigation. Using ERT we could distinguish various layers within the mining dumps. The resistivities of the dumped material differ from the bedrock resistivities at both sites. The GPR measurements show near surface layer boundaries down to 3 - 4 m. In consecutive campaigns 100 MHz and 200 MHz antennas were used. The GPR results (layer boundaries) were included into the ERT inversion algorithm to enable more precise and stable resistivity models. This needs some special preprocessing steps. The 3D-Position of every electrode from ERT measurement and the GPR antenna position on the surface require an accuracy of less than 1cm. At some points, the layer boundaries and radar wave velocities can be calibrated with borehole stratigraphic data from a mineralogical drilling campaign. This is important for a precise time-depth conversion of reflectors from GPR measurement. This reflectors were taken from radargram and have been adopted as resistivity boundary in the start model of the geoelectric inversion algorithm.

Modelling accumulation of marine plastics in the coastal zone; what are the dominant physical processes?

NASA Astrophysics Data System (ADS)

Critchell, Kay; Lambrechts, Jonathan

2016-03-01

Anthropogenic marine debris, mainly of plastic origin, is accumulating in estuarine and coastal environments around the world causing damage to fauna, flora and habitats. Plastics also have the potential to accumulate in the food web, as well as causing economic losses to tourism and sea-going industries. If we are to manage this increasing threat, we must first understand where debris is accumulating and why these locations are different to others that do not accumulate large amounts of marine debris. This paper demonstrates an advection-diffusion model that includes beaching, settling, resuspension/re-floating, degradation and topographic effects on the wind in nearshore waters to quantify the relative importance of these physical processes governing plastic debris accumulation. The aim of this paper is to prioritise research that will improve modelling outputs in the future. We have found that the physical characteristic of the source location has by far the largest effect on the fate of the debris. The diffusivity, used to parameterise the sub-grid scale movements, and the relationship between debris resuspension/re-floating from beaches and the wind shadow created by high islands also has a dramatic impact on the modelling results. The rate of degradation of macroplastics into microplastics also have a large influence in the result of the modelling. The other processes presented (settling, wind drift velocity) also help determine the fate of debris, but to a lesser degree. These findings may help prioritise research on physical processes that affect plastic accumulation, leading to more accurate modelling, and subsequently management in the future.

Experimental validation on the effect of material geometries and processing methodology of Polyoxymethylene (POM)

NASA Astrophysics Data System (ADS)

Hafizzal, Y.; Nurulhuda, A.; Izman, S.; Khadir, AZA

2017-08-01

POM-copolymer bond breaking leads to change depending with respect to processing methodology and material geometries. This paper present the oversights effect on the material integrity due to different geometries and processing methodology. Thermo-analytical methods with reference were used to examine the degradation of thermomechanical while Thermogravimetric Analysis (TGA) was used to judge the thermal stability of sample from its major decomposition temperature. Differential Scanning Calorimetry (DSC) investigation performed to identify the thermal behaviour and thermal properties of materials. The result shown that plastic gear geometries with injection molding at higher tonnage machine more stable thermally rather than resin geometries. Injection plastic gear geometries at low tonnage machine faced major decomposition temperatures at 313.61°C, 305.76 °C and 307.91 °C while higher tonnage processing method are fully decomposed at 890°C, significantly higher compared to low tonnage condition and resin geometries specimen at 398°C. Chemical composition of plastic gear geometries with injection molding at higher and lower tonnage are compare based on their moisture and Volatile Organic Compound (VOC) content, polymeric material content and the absence of filler. Results of higher moisture and Volatile Organic Compound (VOC) content are report in resin geometries (0.120%) compared to higher tonnage of injection plastic gear geometries which is 1.264%. The higher tonnage of injection plastic gear geometry are less sensitive to thermo-mechanical degradation due to polymer chain length and molecular weight of material properties such as tensile strength, flexural strength, fatigue strength and creep resistance.

Electrical Resistance Tomography to Monitor Mitigation of Metal-Toxic Acid-Leachates Ruby Gulch Waste Rock Repository Gilt Edge Mine Superfund Site, South Dakota USA

NASA Astrophysics Data System (ADS)

Versteeg, R.; Heath, G.; Richardson, A.; Paul, D.; Wangerud, K.

2003-12-01

At a cyanide heap-leach open-pit mine, 15-million cubic yards of acid-generating sulfides were dumped at the head of a steep-walled mountain valley, with 30 inches/year precipitation generating 60- gallons/minute ARD leachate. Remediation has reshaped the dump to a 70-acre, 3.5:1-sloped geometry, installed drainage benches and runoff diversions, and capped the repository and lined diversions with a polyethylene geomembrane and cover system. Monitoring was needed to evaluate (a) long-term geomembrane integrity, (b) diversion liner integrity and long-term effectiveness, (c) ARD geochemistry, kinetics and pore-gas dynamics within the repository mass, and (d) groundwater interactions. Observation wells were paired with a 600-electrode resistivity survey system. Using near-surface and down-hole electrodes and automated data collection and post-processing, periodic two- and three-dimensional resistivity images are developed to reflect current and changed-conditions in moisture, temperature, geochemical components, and flow-direction analysis. Examination of total resistivity values and time variances between images allows direct observation of liner and cap integrity with precise identification and location of leaks; likewise, if runoff migrates from degraded diversion ditches into the repository zone, there is an accompanying and noticeable change in resistivity values. Used in combination with monitoring wells containing borehole resistivity electrodes (calibrated with direct sampling of dump water/moisture, temperature and pore-gas composition), the resistivity arrays allow at-depth imaging of geochemical conditions within the repository mass. The information provides early indications of progress or deficiencies in de-watering and ARD- mitigation that is the remedy intent. If emerging technologies present opportunities for secondary treatment, deep resistivity images may assist in developing application methods and evaluating the effectiveness of any reagents introduced into the repository mass to further effect changes in oxidation/reduction reactions.

Linking human health, climate change, and food security through ecological-based sanitation systems

NASA Astrophysics Data System (ADS)

Ryals, R.; Kramer, S.; Porder, S.; Andersen, G. L.

2015-12-01

Ensuring access to clean, safe sanitation for the world's population remains a challenging, yet critical, global sustainability goal. Ecological-based sanitation (EcoSan) technology is a promising strategy for improving sanitation, particularly in areas where financial resources and infrastructure are limiting. The composting of human waste and its use as an agricultural soil amendment can tackle three important challenges in developing countries - providing improved sanitation for vulnerable communities, reducing the spread of intestinal-born pathogens, and returning nutrients and organic matter to degraded agricultural soils. The extent of these benefits and potential tradeoffs are not well known, but have important implications for the widespread adoption of this strategy to promote healthy communities and enhance food security. We quantified the effects of EcoSan on the climate and human health in partnership with Sustainable Organic Integrated Livelihoods (SOIL) in Haiti. We measured greenhouse gas emissions (nitrous oxide, methane, and carbon dioxide) from compost piles that ranged in age from 0 to 14 months (i.e. finished) from two compost facilities managed with or without cement lining. We also measured emissions from a government-operated waste treatment pond and a grass field where waste has been illegally dumped. The highest methane emissions were observed from the anaerobic waste pond, whereas the dump site and compost piles had higher nitrous oxide emissions. Net greenhouse gases (CO2-equivalents) from unlined compost piles were 8x lower than lined compost piles and 20 and 30x lower than the dump and waste pond, respectively. We screened finished compost for fecal pathogens using bacterial 16S sequencing. Bacterial pathogens were eliminated regardless of the type of composting process. Pilot trials indicate that the application of compost to crops has a large potential for increasing food production. This research suggests that EcoSan systems are effective at achieving multiple sustainability goals including the provision of sanitation, mitigating climate change, and increasing food security.

Method for Location of An External Dump in Surface Mining Using the A-Star Algorithm

NASA Astrophysics Data System (ADS)

Zajączkowski, Maciej; Kasztelewicz, Zbigniew; Sikora, Mateusz

2014-10-01

The construction of a surface mine always involves the necessity of accessing deposits through the removal of the residual overburden above. In the beginning phase of exploitation, the masses of overburden are located outside the perimeters of the excavation site, on the external dump, until the moment of internal dumping. In the case of lignite surface mines, these dumps can cover a ground surface of several dozen to a few thousand hectares. This results from a high concentration of lignite extraction, counted in millions of Mg per year, and the relatively large depth of its residual deposits. Determining the best place for the location of an external dump requires a detailed analysis of existing options, followed by a choice of the most favorable one. This article, using the case study of an open-cast lignite mine, presents the selection method for an external dump location based on graph theory and the A-star algorithm. This algorithm, based on the spatial distribution of individual intersections on the graph, seeks specified graph states, continually expanding them with additional elementary fields until the required surface area for the external dump - defined by the lowest value of the occupied site - is achieved. To do this, it is necessary to accurately identify the factors affecting the choice of dump location. On such a basis, it is then possible to specify the target function, which reflects the individual costs of dump construction on a given site. This is discussed further in chapter 3. The area of potential dump location has been divided into elementary fields, each represented by a corresponding geometrical locus. Ascribed to this locus, in addition to its geodesic coordinates, are the appropriate attributes reflecting the degree of development of its elementary field. These tasks can be carried out automatically thanks to the integration of the method with the system of geospatial data management for the given area. The collection of loci, together with geodesic coordinates, constitutes the points on the graph used during exploration. This is done using the A-star algorithm, which uses a heuristic function, allowing it to identify the optimal solution; therefore, the collection of elementary fields, which occupy the potential construction area of a dump, characterized by the lowest value representing the cost of occupation and dumping of overburden in the area. The precision of the boundary, generated by the algorithm, is dependent on the established size of the elementary field, and should be refined each time by the designer of the surface mine. This article presents the application of the above method of dump location using the example of "Tomisławice," a lignite surface mine owned by PAK KWB Konin S. A. The method made it possible to identify the most favorable dump location on the northeast side of the initial pit, within 2 kilometers of its surrounding area (discussed further in chapter 3). This method is universal in nature and, after certain modifications, can be implemented for other surface mines as well.

Millimeter-sized marine plastics: a new pelagic habitat for microorganisms and invertebrates.

PubMed

Reisser, Julia; Shaw, Jeremy; Hallegraeff, Gustaaf; Proietti, Maira; Barnes, David K A; Thums, Michele; Wilcox, Chris; Hardesty, Britta Denise; Pattiaratchi, Charitha

2014-01-01

Millimeter-sized plastics are abundant in most marine surface waters, and known to carry fouling organisms that potentially play key roles in the fate and ecological impacts of plastic pollution. In this study we used scanning electron microscopy to characterize biodiversity of organisms on the surface of 68 small floating plastics (length range = 1.7-24.3 mm, median = 3.2 mm) from Australia-wide coastal and oceanic, tropical to temperate sample collections. Diatoms were the most diverse group of plastic colonizers, represented by 14 genera. We also recorded 'epiplastic' coccolithophores (7 genera), bryozoans, barnacles (Lepas spp.), a dinoflagellate (Ceratium), an isopod (Asellota), a marine worm, marine insect eggs (Halobates sp.), as well as rounded, elongated, and spiral cells putatively identified as bacteria, cyanobacteria, and fungi. Furthermore, we observed a variety of plastic surface microtextures, including pits and grooves conforming to the shape of microorganisms, suggesting that biota may play an important role in plastic degradation. This study highlights how anthropogenic millimeter-sized polymers have created a new pelagic habitat for microorganisms and invertebrates. The ecological ramifications of this phenomenon for marine organism dispersal, ocean productivity, and biotransfer of plastic-associated pollutants, remains to be elucidated.

Millimeter-Sized Marine Plastics: A New Pelagic Habitat for Microorganisms and Invertebrates

PubMed Central

Reisser, Julia; Shaw, Jeremy; Hallegraeff, Gustaaf; Proietti, Maira; Barnes, David K. A.; Thums, Michele; Wilcox, Chris; Hardesty, Britta Denise; Pattiaratchi, Charitha

2014-01-01

Millimeter-sized plastics are abundant in most marine surface waters, and known to carry fouling organisms that potentially play key roles in the fate and ecological impacts of plastic pollution. In this study we used scanning electron microscopy to characterize biodiversity of organisms on the surface of 68 small floating plastics (length range = 1.7–24.3 mm, median = 3.2 mm) from Australia-wide coastal and oceanic, tropical to temperate sample collections. Diatoms were the most diverse group of plastic colonizers, represented by 14 genera. We also recorded ‘epiplastic’ coccolithophores (7 genera), bryozoans, barnacles (Lepas spp.), a dinoflagellate (Ceratium), an isopod (Asellota), a marine worm, marine insect eggs (Halobates sp.), as well as rounded, elongated, and spiral cells putatively identified as bacteria, cyanobacteria, and fungi. Furthermore, we observed a variety of plastic surface microtextures, including pits and grooves conforming to the shape of microorganisms, suggesting that biota may play an important role in plastic degradation. This study highlights how anthropogenic millimeter-sized polymers have created a new pelagic habitat for microorganisms and invertebrates. The ecological ramifications of this phenomenon for marine organism dispersal, ocean productivity, and biotransfer of plastic-associated pollutants, remains to be elucidated. PMID:24941218

Determining the radon exhalation rate from a gold mine tailings dump by measuring the gamma radiation.

PubMed

Ongori, Joash N; Lindsay, Robert; Newman, Richard T; Maleka, Peane P

2015-02-01

The mining activities taking place in Gauteng province, South Africa have caused millions of tons of rocks to be taken from underground to be milled and processed to extract gold. The uranium bearing tailings are placed in an estimated 250 dumps covering a total area of about 7000 ha. These tailings dumps contain considerable amounts of radium and have therefore been identified as large sources of radon. The size of these dumps make traditional radon exhalation measurements time consuming and it is difficult to get representative measurements for the whole dump. In this work radon exhalation measurements from the non-operational Kloof mine dump have been performed by measuring the gamma radiation from the dump fairly accurately over an area of more than 1 km(2). Radon exhalation from the mine dump have been inferred from this by laboratory-based and in-situ gamma measurements. Thirty four soil samples were collected at depths of 30 cm and 50 cm. The weighted average activity concentrations in the soil samples were 308 ± 7 Bq kg(-1), 255 ± 5 Bq kg(-1) and 18 ± 1 Bq kg(-1) for (238)U, (40)K and (232)Th, respectively. The MEDUSA (Multi-Element Detector for Underwater Sediment Activity) γ-ray detection system was used for field measurements. The radium concentrations were then used with soil parameters to obtain the radon flux using different approaches such as the IAEA (International Atomic Energy Agency) formula. Another technique the MEDUSA Laboratory Technique (MELT) was developed to map radon exhalation based on (1) recognising that radon exhalation does not affect (40)K and (232)Th activity concentrations and (2) that the ratio of the activity concentration of the field (MEDUSA) to the laboratory (HPGe) for (238)U and (40)K or (238)U and (232)Th will give a measure of the radon exhalation at a particular location in the dump. The average, normalised radon flux was found to be 0.12 ± 0.02 Bq m(-2) s(-1) for the mine dump. Copyright © 2014 Elsevier Ltd. All rights reserved.

Estimates of water and solute release from a coal waste rock dump in the Elk Valley, British Columbia, Canada.

PubMed

Villeneuve, S A; Barbour, S L; Hendry, M J; Carey, S K

2017-12-01

Long term (1999 to 2014) flow and water quality data from a rock drain located at the base of a coal waste rock dump constructed in the Elk Valley, British Columbia was used to characterize the release of three solutes (NO 3 - , Cl - and SO 4 2- ) from the dump and obtain whole dump estimates of net percolation (NP). The concentrations of dump derived solutes in the rock drain water were diluted by snowmelt waters from the adjacent natural watershed during the spring freshet and reached a maximum concentration during the winter baseflow period. Historical peak baseflow concentrations of conservative ions (NO 3 - and Cl - ) increased until 2006/07 after which they decreased. This decrease was attributed to completion of the flushing of the first pore volume of water stored within the dump. The baseflow SO 4 2- concentrations increased proportionally with NO 3 - and Cl - to 2007, but then continued to slowly increase as NO 3 - and Cl - concentrations decreased. This was attributed to ongoing production of SO 4 2- due to oxidation of sulfide minerals within the dump. Based on partitioning of the annual volume of water discharged from the rock drain to waste rock effluent (NP) and water entering the rock drain laterally from the natural watershed, the mean NP values were estimated to be 446±50mm/a (area normalized net percolation/year) for the dump and 172±71mm/a for the natural watershed. The difference was attributed to greater rates of recharge in the dump from summer precipitation compared to the natural watershed where rainfall interception and enhanced evapotranspiration will increase water losses. These estimates included water moving through subsurface pathways. However, given the limitations in quantifying these flows the estimated NP rates for both the natural watershed and the waste rock dump are considered to be low, and could be much higher (e.g. ~450mm/a and ~800mm/a). Copyright © 2017 Elsevier B.V. All rights reserved.

Biodegradation of plastics: current scenario and future prospects for environmental safety.

PubMed

Ahmed, Temoor; Shahid, Muhammad; Azeem, Farrukh; Rasul, Ijaz; Shah, Asad Ali; Noman, Muhammad; Hameed, Amir; Manzoor, Natasha; Manzoor, Irfan; Muhammad, Sher

2018-03-01

Plastic is a general term used for a wide range of high molecular weight organic polymers obtained mostly from the various hydrocarbon and petroleum derivatives. There is an ever-increasing trend towards the production and consumption of plastics due to their extensive industrial and domestic applications. However, a wide spectrum of these polymers is non-biodegradable with few exceptions. The extensive use of plastics, lack of waste management, and casual community behavior towards their proper disposal pose a significant threat to the environment. This has raised growing concerns among various stakeholders to devise policies and innovative strategies for plastic waste management, use of biodegradable polymers especially in packaging, and educating people for their proper disposal. Current polymer degradation strategies rely on chemical, thermal, photo, and biological procedures. In the presence of proper waste management strategies coupled with industrially controlled biodegradation facilities, the use of biodegradable plastics for some applications such as packaging or health industry is a promising and attractive option for economic, environmental, and health benefits. This review highlights the classification of plastics with special emphasis on biodegradable plastics and their rational use, the identified mechanisms of plastic biodegradation, the microorganisms involved in biodegradation, and the current insights into the research on biodegradable plastics. The review has also identified the research gaps in plastic biodegradation followed by future research directions.

Transport and release of chemicals from plastics to the environment and to wildlife.

PubMed

Teuten, Emma L; Saquing, Jovita M; Knappe, Detlef R U; Barlaz, Morton A; Jonsson, Susanne; Björn, Annika; Rowland, Steven J; Thompson, Richard C; Galloway, Tamara S; Yamashita, Rei; Ochi, Daisuke; Watanuki, Yutaka; Moore, Charles; Viet, Pham Hung; Tana, Touch Seang; Prudente, Maricar; Boonyatumanond, Ruchaya; Zakaria, Mohamad P; Akkhavong, Kongsap; Ogata, Yuko; Hirai, Hisashi; Iwasa, Satoru; Mizukawa, Kaoruko; Hagino, Yuki; Imamura, Ayako; Saha, Mahua; Takada, Hideshige

2009-07-27

Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2'-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bisphenol A, at concentrations from sub ng g(-1) to microg g(-1). Some of these compounds are added during plastics manufacture, while others adsorb from the surrounding seawater. Concentrations of hydrophobic contaminants adsorbed on plastics showed distinct spatial variations reflecting global pollution patterns. Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride. Both a mathematical model using equilibrium partitioning and experimental data have demonstrated the transfer of contaminants from plastic to organisms. A feeding experiment indicated that PCBs could transfer from contaminated plastics to streaked shearwater chicks. Plasticizers, other plastics additives and constitutional monomers also present potential threats in terrestrial environments because they can leach from waste disposal sites into groundwater and/or surface waters. Leaching and degradation of plasticizers and polymers are complex phenomena dependent on environmental conditions in the landfill and the chemical properties of each additive. Bisphenol A concentrations in leachates from municipal waste disposal sites in tropical Asia ranged from sub microg l(-1) to mg l(-1) and were correlated with the level of economic development.

Transport and release of chemicals from plastics to the environment and to wildlife

PubMed Central

Teuten, Emma L.; Saquing, Jovita M.; Knappe, Detlef R. U.; Barlaz, Morton A.; Jonsson, Susanne; Björn, Annika; Rowland, Steven J.; Thompson, Richard C.; Galloway, Tamara S.; Yamashita, Rei; Ochi, Daisuke; Watanuki, Yutaka; Moore, Charles; Viet, Pham Hung; Tana, Touch Seang; Prudente, Maricar; Boonyatumanond, Ruchaya; Zakaria, Mohamad P.; Akkhavong, Kongsap; Ogata, Yuko; Hirai, Hisashi; Iwasa, Satoru; Mizukawa, Kaoruko; Hagino, Yuki; Imamura, Ayako; Saha, Mahua; Takada, Hideshige

2009-01-01

Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2′-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bisphenol A, at concentrations from sub ng g–1 to µg g–1. Some of these compounds are added during plastics manufacture, while others adsorb from the surrounding seawater. Concentrations of hydrophobic contaminants adsorbed on plastics showed distinct spatial variations reflecting global pollution patterns. Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride. Both a mathematical model using equilibrium partitioning and experimental data have demonstrated the transfer of contaminants from plastic to organisms. A feeding experiment indicated that PCBs could transfer from contaminated plastics to streaked shearwater chicks. Plasticizers, other plastics additives and constitutional monomers also present potential threats in terrestrial environments because they can leach from waste disposal sites into groundwater and/or surface waters. Leaching and degradation of plasticizers and polymers are complex phenomena dependent on environmental conditions in the landfill and the chemical properties of each additive. Bisphenol A concentrations in leachates from municipal waste disposal sites in tropical Asia ranged from sub µg l–1 to mg l–1 and were correlated with the level of economic development. PMID:19528054

19 CFR 159.58 - Dumping and countervailing duties; action by port director.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 2 2013-04-01 2013-04-01 false Dumping and countervailing duties; action by port director. 159.58 Section 159.58 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... Dumping and countervailing duties; action by port director. (a) Antidumping matters. Upon receipt of...

19 CFR 159.58 - Dumping and countervailing duties; action by port director.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 2 2011-04-01 2011-04-01 false Dumping and countervailing duties; action by port director. 159.58 Section 159.58 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... Dumping and countervailing duties; action by port director. (a) Antidumping matters. Upon receipt of...

19 CFR 159.58 - Dumping and countervailing duties; action by port director.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 2 2012-04-01 2012-04-01 false Dumping and countervailing duties; action by port director. 159.58 Section 159.58 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... Dumping and countervailing duties; action by port director. (a) Antidumping matters. Upon receipt of...

19 CFR 159.58 - Dumping and countervailing duties; action by port director.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false Dumping and countervailing duties; action by port director. 159.58 Section 159.58 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... Dumping and countervailing duties; action by port director. (a) Antidumping matters. Upon receipt of...

19 CFR 159.58 - Dumping and countervailing duties; action by port director.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 2 2014-04-01 2014-04-01 false Dumping and countervailing duties; action by port director. 159.58 Section 159.58 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND... Dumping and countervailing duties; action by port director. (a) Antidumping matters. Upon receipt of...

77 FR 31423 - Qualification of Drivers; Application for Exemptions; National Association of the Deaf

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-25

... dump trucks and tractor trailer trucks. He would like to drive tractor trailer trucks in interstate... CDL and drive heavy equipment such as a dump truck, or rig truck with a trailer, if granted an... intrastate commerce. This includes experience driving heavy equipment, dump trucks and public works trucks...

27 CFR 19.343 - Use of spirits, wines, and alcoholic flavoring materials.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Use of spirits, wines, and alcoholic flavoring materials. A proprietor must prepare a dump/batch... ingredients used in the manufacture of a distilled spirits product according to the following rules. (a) Dump record. A proprietor must prepare a dump record when spirits, wines, or alcoholic flavoring materials are...

40 CFR 220.1 - Purpose and scope.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING GENERAL § 220.1 Purpose... material for the purpose of dumping it in ocean waters pursuant to section 103 of the Act. Except as may be... shall transport from the United States any material for the purpose of dumping it into ocean waters; (2...

40 CFR 220.1 - Purpose and scope.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING GENERAL § 220.1 Purpose... material for the purpose of dumping it in ocean waters pursuant to section 103 of the Act. Except as may be... shall transport from the United States any material for the purpose of dumping it into ocean waters; (2...

40 CFR 220.1 - Purpose and scope.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING GENERAL § 220.1 Purpose... material for the purpose of dumping it in ocean waters pursuant to section 103 of the Act. Except as may be... shall transport from the United States any material for the purpose of dumping it into ocean waters; (2...

19 CFR 159.61 - General.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 2 2011-04-01 2011-04-01 false General. 159.61 Section 159.61 Customs Duties U.S...) LIQUIDATION OF DUTIES Continued Dumping and Subsidy Offset § 159.61 General. (a) Continued dumping and subsidy... U.S.C. 1675c), known as the Continued Dumping and Subsidy Offset Act of 2000, assessed duties...

19 CFR 159.61 - General.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 2 2010-04-01 2010-04-01 false General. 159.61 Section 159.61 Customs Duties U.S...) LIQUIDATION OF DUTIES Continued Dumping and Subsidy Offset § 159.61 General. (a) Continued dumping and subsidy... U.S.C. 1675c), known as the Continued Dumping and Subsidy Offset Act of 2000, assessed duties...

[Inactive dumps in Santa Catarina's carboniferous area: analysis of risks to the public health and the environment].

PubMed

Possamai, Fernando Pagani; Viana, Ednilson; Schulz, Harry Edmar; de Costa, Marcel Madeira; Casagrande, Everson

2007-01-01

The existence of inactive dumps considerably increases the so-called "environmental liability"; so much so that the final destination of urban solid residues takes a prominent place on the list of environmental issues of societies(1). In the state of Santa Catarina, it can be said that, currently, the real conditions of the "final destination deposits", or simply the inactive dumps, is officially unknown. This is maybe most evident in the carboniferous area of the state that already suffers from the environmental impact of coal mining. This study attempts to make a survey of the inactive dumps in the carboniferous area of Santa Catarina, analysing the risks they represent to public health and to the environment. The results gathered show that, of the eleven municipal districts in the carboniferous area, nine have inactive dumps. In these nine districts, there are eleven inactive dumps that, according to the this evaluation, represent a large risk to public health and the environment when the parameters analysed are taken into acount.

Assessment of heavy metal contamination in soil due to leachate migration from an open dumping site

NASA Astrophysics Data System (ADS)

Kanmani, S.; Gandhimathi, R.

2013-03-01

The concentration of heavy metals was studied in the soil samples collected around the municipal solid waste (MSW) open dumpsite, Ariyamangalam, Tiruchirappalli, Tamilnadu to understand the heavy metal contamination due to leachate migration from an open dumping site. The dump site receives approximately 400-470 tonnes of municipal solid waste. Solid waste characterization was carried out for the fresh and old municipal solid waste to know the basic composition of solid waste which is dumped in the dumping site. The heavy metal concentration in the municipal solid waste fine fraction and soil samples were analyzed. The heavy metal concentration in the collected soil sample was found in the following order: Mn > Pb > Cu > Cd. The presence of heavy metals in soil sample indicates that there is appreciable contamination of the soil by leachate migration from an open dumping site. However, these pollutants species will continuously migrated and attenuated through the soil strata and after certain period of time they might contaminate the groundwater system if there is no action to be taken to prevent this phenomenon.

Continuous Wheel Momentum Dumping Using Magnetic Torquers and Thrusters

NASA Astrophysics Data System (ADS)

Oh, Hwa-Suk; Choi, Wan-Sik; Eun, Jong-Won

1996-12-01

Two momentum management schemes using magnetic torquers and thrusters are sug-gested. The stability of the momentum dumping logic is proved at a general attitude equilibrium. Both momentum dumping control laws are implemented with Pulse-Width- Pulse-Frequency Modulated on-off control, and shown working equally well with the original continuous and variable strength control law. Thrusters are assummed to be asymmetrically configured as a contingency case. Each thruster is fired following separated control laws rather than paired thrusting. Null torque thrusting control is added on the thrust control calculated from the momentum control law for the gener-ation of positive thrusting force. Both magnetic and thrusting control laws guarantee the momentum dumping, however, the wheel inner loop control is needed for the "wheel speed" dumping, The control laws are simulated on the KOrea Multi-Purpose SATellite (KOMPSAT) model.

Geophysical exploration of historical mine dumps for the estimation of valuable residuals

NASA Astrophysics Data System (ADS)

Martin, Tina; Knieß, Rudolf; Noell, Ursula; Hupfer, Sarah; Kuhn, Kerstin; Günther, Thomas

2015-04-01

Within the project ROBEHA, funded by the German Federal Ministry of Education and Research (033R105) the economic potential of different abandoned dump sites for mine waste in the Harz Mountains was investigated. Two different mining dumps were geophysically and mineralogically analysed in order to characterize the mine dump structure and to estimate the volume of the potential recycling material. The geophysical methods comprised geoelectrics, radar, and spectral induced polarization (SIP). One about 100-year old mining dump containing residues from density separated Ag- and Sb-rich Pb (Zn)-gangue ores was investigated in detail. Like most small-scale mining waste disposal sites this investigated dump is very heterogeneously structured. Therefore, 27 geoelectrical profiles, more than 50 radar profiles, and several SIP profiles were measured and analysed. The results from the radar measurements, registered with the GSSI system and a shielded 200 MHz antenna, show the near surface boundary layer (down to 3-4 m beneath surface) of the waste residuals. These results can be used as pre-information for the inversion process of the geoelectrical data. The geoelectrical results reveal the mineral residues as layers with higher resistivities (> 300 Ohm*m) than the surrounding material. The SIP method found low phase signals (< 0.5°) for the residues. To estimate the volume of the potentially reusable material we analysed each geoelectrical profile and interpolated between the single profiles using the BERT algorithm. Taking into account the wooded areas of the mine dump and other parameters we get a first estimate for the volume of the residues but the economical viability and the environmental impact of the reworking of the dump still needs to be evaluated in detail. The results of the second mine dump, an abandoned Cu and Zn-rich slag heap, show that the slag residues are characterized by higher resistivities and higher phases. A localization of the slag residues which are covered by organic material could be realized applying these geophysical methods.

Plastics Distribution and Degradation on Lake Huron Beaches

NASA Astrophysics Data System (ADS)

Zbyszewski, M.; Corcoran, P.

2009-05-01

The resistivity of plastic debris to chemical and mechanical weathering processes poses a serious threat to the environment. Numerous marine beaches are littered with plastic fragments that entangle and become ingested by organisms including birds, turtles and plankton. Although many studies have been conducted to determine the amount and effects of plastics pollution on marine organisms, relatively little is known about the distribution and quantity of polymer types along lacustrine beaches. Plastic particles sampled from selected beaches on Lake Huron were analyzed using Fourier Transform Infrared Spectroscopy (FTIR) to determine polymer composition. The majority of the plastic fragments are industrial pellets composed of polypropylene and polyethylene. Varying degrees of oxidation are indicated by multiple irregular peaks in the lower wavenumber region on the FTIR spectra. The oxidized pellets also represent the plastic particles with the most pronounced surface textures, as identified using Scanning Electron Microscopy (SEM). Crazes and flakey, fibrous, or granular textures are consistent with chemical weathering processes, whereas gauges and pits occur through abrasion during mechanical weathering. Further textural and compositional analysis will indicate which polymer types are more resistant to weathering processes. Additional investigation of the distribution of plastic debris along the beaches of Lake Huron will indicate the amount and primary transport directions of resistant plastic debris polluting one of Ontario's Great Lakes.

Settlement analysis of fresh and partially stabilised municipal solid waste in simulated controlled dumps and bioreactor landfills.

PubMed

Swati, M; Joseph, Kurian

2008-01-01

The patterns of settlement of fresh as well as partially stabilised municipal solid waste (MSW), undergoing degradation in five different landfill lysimeters, were studied elaborately. The first two lysimeters, R1 and R2, contained fresh MSW while the other three lysimeters, R3, R4 and R5, contained partially stabilised MSW. R1 and R3 simulated conventional controlled dumps with fortnightly disposal of drained leachate. R2 and R4 simulated bioreactor landfills with leachate recirculation. Fortnightly water flushing was done in R5. Settlement of MSW, monitored over a period of 58 weeks, was correlated with the organic carbon content of leachate and residual volatile matter in the MSW to establish the relationship between settlement and organic destruction. Compressibility parameters such as modulus of elasticity and compression indices were determined and empirical equations were applied for the settlement data. Overall settlements up to 49% were observed in the case of landfill lysimeters, filled with fresh MSW. Landfill lysimeters with liquid addition, in the form of leachate or water, experienced lower primary settlements and higher secondary settlements than conventional fills, where no liquid addition was practised. Modified secondary compression indices for MSW in lysimeters with leachate recirculation and flushing were 30%-44% higher than that for lysimeters where no liquid addition was done. Secondary settlements in bioreactor landfills were found to vary exponentially with time.

System dynamic modeling on construction waste management in Shenzhen, China.

PubMed

Tam, Vivian W Y; Li, Jingru; Cai, Hong

2014-05-01

This article examines the complexity of construction waste management in Shenzhen, Mainland China. In-depth analysis of waste generation, transportation, recycling, landfill and illegal dumping of various inherent management phases is explored. A system dynamics modeling using Stella model is developed. Effects of landfill charges and also penalties from illegal dumping are also simulated. The results show that the implementation of comprehensive policy on both landfill charges and illegal dumping can effectively control the illegal dumping behavior, and achieve comprehensive construction waste minimization. This article provides important recommendations for effective policy implementation and explores new perspectives for Shenzhen policy makers.

Challenges and Plans for Injection and Beam Dump

NASA Astrophysics Data System (ADS)

Barnes, M.; Goddard, B.; Mertens, V.; Uythoven, J.

The injection and beam dumping systems of the LHC will need to be upgraded to comply with the requirements of operation with the HL-LHC beams. The elements of the injection system concerned are the fixed and movable absorbers which protect the LHC in case of an injection kicker error and the injection kickers themselves. The beam dumping system elements under study are the absorbers which protect the aperture in case of an asynchronous beam dump and the beam absorber block. The operational limits of these elements and the new developments in the context of the HL-LHC project are described.

PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENTOF DUMPING SYNDROME AND ITS RELATION TO BARIATRIC SURGERY.

PubMed

Chaves, Yasmin da Silva; Destefani, Afrânio Côgo

The dumping syndrome is frequent in bariatric surgery. It is probably the most common syndrome following partial or complete gastrectomy. Its prevalence in partial gastrectomy can reach up to 50%, thus it can be a significant complication arising from some types of bariatric surgeries. Critical analysis on dumping syndrome, its pathophysiology, diagnosis and treatment. A literature review was performed using the key words: 'dumping syndrome', 'bariatric surgery' and 'rapid dumping syndrome'. Inclusion criteria were: books, original works, case reports and meta-analyzes, and the exclusion criterion was literature review. Concerning the publication time, articles were screened between 1960 and May 2015. The dumping syndrome is complication arising from obesity surgeries, but also can be a result of vagus nerve damage. Diagnosis is done primarily through the use of questionnaires based on scores. The Sigstad score and Arts survey are valid means for assessing the dumping syndrome. Initial therapy consists in the adoption of dietary measures, short acting drugs administration. A síndrome de dumping é frequente após operações bariátricas. É, provavelmente, a mais comum das síndromes que sucedem gastrectomias parciais ou completas. Sua prevalência, em gastrectomias parciais pode chegar a até 50%, tornando-se assim complicação significante em alguns tipos de operações bariátricas. Realizar análise crítica sobre a síndrome de dumping em sua fisiopatologia, diagnóstico e tratamento. Foi realizada revisão bibliográfica utilizando os descritores: 'síndrome de dumping', 'cirurgia bariátrica' e 'síndrome do esvaziamento rápido'. Os critérios de inclusão foram: livros, trabalhos originais, relatos de caso e metanálises; excluíram-se as revisões bibliográficas. Quanto ao tempo de publicação, foram selecionados artigos entre 1960 e maio de 2015. A síndrome de dumping é complicação gastrointestinal oriunda de operações para obesidade, mas também pode ocasionar-se como consequência de danos no nervo vago. Seu diagnóstico é realizado primordialmente através da aplicação de questionários baseados em pontuações. O escore de Sigstad e questionário de Arts são meios válidos para avaliação da síndrome de dumping. A terapia inicial consiste na adoção de medidas dietéticas, ou fármacos administráveis de ação curta.

Biochemistry of Microbial Degradation of Hexachlorocyclohexane and Prospects for Bioremediation

PubMed Central

Lal, Rup; Pandey, Gunjan; Sharma, Pooja; Kumari, Kirti; Malhotra, Shweta; Pandey, Rinku; Raina, Vishakha; Kohler, Hans-Peter E.; Holliger, Christof; Jackson, Colin; Oakeshott, John G.

2010-01-01

Summary: Lindane, the γ-isomer of hexachlorocyclohexane (HCH), is a potent insecticide. Purified lindane or unpurified mixtures of this and α-, β-, and δ-isomers of HCH were widely used as commercial insecticides in the last half of the 20th century. Large dumps of unused HCH isomers now constitute a major hazard because of their long residence times in soil and high nontarget toxicities. The major pathway for the aerobic degradation of HCH isomers in soil is the Lin pathway, and variants of this pathway will degrade all four of the HCH isomers although only slowly. Sequence differences in the primary LinA and LinB enzymes in the pathway play a key role in determining their ability to degrade the different isomers. LinA is a dehydrochlorinase, but little is known of its biochemistry. LinB is a hydrolytic dechlorinase that has been heterologously expressed and crystallized, and there is some understanding of the sequence-structure-function relationships underlying its substrate specificity and kinetics, although there are also some significant anomalies. The kinetics of some LinB variants are reported to be slow even for their preferred isomers. It is important to develop a better understanding of the biochemistries of the LinA and LinB variants and to use that knowledge to build better variants, because field trials of some bioremediation strategies based on the Lin pathway have yielded promising results but would not yet achieve economic levels of remediation. PMID:20197499

Leaching of brominated flame retardants from TV housing plastics in the presence of dissolved humic matter.

PubMed

Choi, Ki-In; Lee, Suk-Hui; Osako, Masahiro

2009-01-01

In this study, we investigated the contents of several brominated compounds in TV molding plastics, as well as their leaching characteristics in the presence of DHM. The PBDE content was about 3% of the sample weight, and deca-BDE was the most abundant homologue, accounting for over 80% of the total amount. TBBPA, PBPs and PBBs content was 8100, 4700 and 250 ng/g, respectively. Despite no detection of most of the lower brominated DEs in distilled water, most homologues could be detected in DHM solution, and their solubility increased according to the contact time; those of highly brominated compounds increased to 10 times their maximum solubility in distilled water. Especially, contrary to the relatively faster equilibrium in distilled water, BFR solubility in DHM solution was maintained even after 20 days. In addition, a modified first-order model adequately reflected rapid desorption for each compound in the initial period, but slow desorption afterwards. From an overall perspective, it is clear that hydrophobic BFRs can leach out to a great extent in the presence of DHM, which is a matter of great concern in E&E waste as the potential contaminant source of BFRs, especially in landfills and open dump sites that provide the perfect conditions for exposure of BFRs to abundant DHM.

Practices, Concerns, and Willingness to Participate in Solid Waste Management in Two Urban Slums in Central Uganda

PubMed Central

Ndejjo, Rawlance; Musoke, David; Musinguzi, Geofrey; Halage, Abdullah Ali; Carpenter, David O.; Ssempebwa, John C.

2016-01-01

Poor solid waste management is among the major challenges facing urban slums in developing countries including Uganda. Understanding community concerns and willingness towards involvement in solid waste management improvement initiatives is critical for informing interventions in slums. Methods. We used a cross-sectional study to collect quantitative data from 435 residents in two urban slums in central Uganda. A semistructured questionnaire was used which assessed waste collection practices, separation and disposal methods, concerns regarding solid wastes, and willingness to participate in waste separation and composting. Data was analysed using STATA 12. Results. Food remains (38%) and plastics (37%) formed the biggest proportion of wastes generated in households. Most households (35.9%) disposed of general wastes by open dumping while 27% disposed of plastics by burning. Only 8.8% of households conducted composting while 55% carried out separation for some decomposable wastes. Separation was carried out for only banana peelings and leftover foods for feeding animals. Respondents expressed high willingness to separate (76.6%) and compost (54.9%) solid wastes. Conclusion. Practices in waste disposal and separation were poor despite high willingness to participate in initiatives to improve waste management, highlighting a need for authorities to engage residents of slums to improve their practices. PMID:27066081

Practices, Concerns, and Willingness to Participate in Solid Waste Management in Two Urban Slums in Central Uganda.

PubMed

Mukama, Trasias; Ndejjo, Rawlance; Musoke, David; Musinguzi, Geofrey; Halage, Abdullah Ali; Carpenter, David O; Ssempebwa, John C

2016-01-01

Poor solid waste management is among the major challenges facing urban slums in developing countries including Uganda. Understanding community concerns and willingness towards involvement in solid waste management improvement initiatives is critical for informing interventions in slums. We used a cross-sectional study to collect quantitative data from 435 residents in two urban slums in central Uganda. A semistructured questionnaire was used which assessed waste collection practices, separation and disposal methods, concerns regarding solid wastes, and willingness to participate in waste separation and composting. Data was analysed using STATA 12. Food remains (38%) and plastics (37%) formed the biggest proportion of wastes generated in households. Most households (35.9%) disposed of general wastes by open dumping while 27% disposed of plastics by burning. Only 8.8% of households conducted composting while 55% carried out separation for some decomposable wastes. Separation was carried out for only banana peelings and leftover foods for feeding animals. Respondents expressed high willingness to separate (76.6%) and compost (54.9%) solid wastes. Practices in waste disposal and separation were poor despite high willingness to participate in initiatives to improve waste management, highlighting a need for authorities to engage residents of slums to improve their practices.

Garbage Collection in a Distributed Object-Oriented System

NASA Technical Reports Server (NTRS)

Gupta, Aloke; Fuchs, W. Kent

1993-01-01

An algorithm is described in this paper for garbage collection in distributed systems with object sharing across processor boundaries. The algorithm allows local garbage collection at each node in the system to proceed independently of local collection at the other nodes. It requires no global synchronization or knowledge of the global state of the system and exhibits the capability of graceful degradation. The concept of a specialized dump node is proposed to facilitate the collection of inaccessible circular structures. An experimental evaluation of the algorithm is also described. The algorithm is compared with a corresponding scheme that requires global synchronization. The results show that the algorithm works well in distributed processing environments even when the locality of object references is low.

Assessing the fate of explosives derived nitrate in mine waste rock dumps using the stable isotopes of oxygen and nitrogen.

PubMed

Hendry, M Jim; Wassenaar, Leonard I; Barbour, S Lee; Schabert, Marcie S; Birkham, Tyler K; Fedec, Tony; Schmeling, Erin E

2018-05-29

Ammonium nitrate (NH 4 NO 3 ) mixed with fuel oil is a common blasting agent used to fragment rock into workable size fractions at mines throughout the world. The decomposition and oxidation of undetonated explosives can result in high NO 3 - concentrations in waters emanating from waste rock dumps. We used the stable isotopic composition of NO 3 - (δ 15 N- and δ 18 O-NO 3 - ) to define and quantify the controls on NO 3 - composition in waste rock dumps by studying water-unsaturated and saturated conditions at nine coal waste rock dumps located in the Elk Valley, British Columbia, Canada. Estimates of the extent of nitrification of NH 4 NO 3 in oxic zones in the dumps, initial NO 3 - concentrations prior to denitrification, and the extent of NO 3 - removal by denitrification in sub-oxic to anoxic zones are provided. δ 15 N data from unsaturated waste rock dumps confirm NO 3 - is derived from blasting. δ 15 N- and δ 18 O-NO 3 - data show extensive denitrification can occur in saturated waste rock and in localized zones of elevated water saturation and low oxygen concentrations in unsaturated waste rock. At the mine dump scale, the extent of denitrification in the unsaturated waste rock was inferred from water samples collected from underlying rock drains. Copyright © 2018. Published by Elsevier B.V.

Chevron beam dump for ITER edge Thomson scattering system

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

Yatsuka, E.; Hatae, T.; Bassan, M.

This paper contains the design of the beam dump for the ITER edge Thomson scattering system and mainly concerns its lifetime under the harsh thermal and electromagnetic loads as well as tight space allocation. The lifetime was estimated from the multi-pulse laser-induced damage threshold. In order to extend its lifetime, the structure of the beam dump was optimized. A number of bent sheets aligned parallel in the beam dump form a shape called a chevron which enables it to avoid the concentration of the incident laser pulse energy. The chevron beam dump is expected to withstand thermal loads due tomore » nuclear heating, radiation from the plasma, and numerous incident laser pulses throughout the entire ITER project with a reasonable margin for the peak factor of the beam profile. Structural analysis was also carried out in case of electromagnetic loads during a disruption. Moreover, detailed issues for more accurate assessments of the beam dump's lifetime are clarified. Variation of the bi-directional reflection distribution function (BRDF) due to erosion by or contamination of neutral particles derived from the plasma is one of the most critical issues that needs to be resolved. In this paper, the BRDF was assumed, and the total amount of stray light and the absorbed laser energy profile on the beam dump were evaluated.« less

Threat of plastic ageing in marine environment. Adsorption/desorption of micropollutants.

PubMed

Kedzierski, Mikaël; D'Almeida, Mélanie; Magueresse, Anthony; Le Grand, Adélaïde; Duval, Hélène; César, Guy; Sire, Olivier; Bruzaud, Stéphane; Le Tilly, Véronique

2018-02-01

Ageing of various plastics in marine environment was monitored after immersion of two synthetic (polyvinylchloride, PVC, and polyethylene terephthalate, PET) and one biodegradable (poly(butylene adipate co-terephtalate), PBAT) plastics for 502days in the bay of Lorient (Brittany, France). Data analysis indicates that aged PVC rapidly releases estrogenic compounds in seawater with a later adsorption of heavy metals; PET undergoes a low weakening of the surface whereas no estrogenic activity is detected; PBAT ages faster in marine environment than PVC. Aged PBAT exhibits heterogeneous surface with some cavities likely containing clay minerals from the chlorite group. Besides, this degraded material occasionally shows a high estrogenic activity. Overall, this study reports, for the first time, that some aged plastics, without being cytotoxic, can release estrogenic compounds in marine environment. Copyright © 2017. Published by Elsevier Ltd.

75 FR 26131 - National Oil and Hazardous Substance Pollution Contingency Plan; National Priorities List

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-11

... publishing a direct final Notice of Deletion of the Asbestos Dump Superfund Site (Site), located in Long Hill... Deletion of the Asbestos Dump Superfund site (Site), from the National Priorities List (NPL). The NPL... discusses the Asbestos Dump Superfund Site and demonstrates how it meets the deletion criteria. Section V...

75 FR 44250 - Proposed Administrative Settlement Agreement Under Section 122 of the Comprehensive Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-28

... Dump No. 5 Site located in Jersey City, Hudson County, NJ AGENCY: Environmental Protection Agency... certain response costs incurred by EPA at the Turnpike Dump No. 5 Site (``Site'') located in Jersey City.... ADDRESSES: Comments should reference the Turnpike Dump No. 5 Site, EPA Index No. II-CERCLA-02-2010-2015 and...

76 FR 13208 - Notice of Lodging of Settlement Agreement Under the Clean Air Act, Comprehensive Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-10

... Disposal Superfund Site in Kansas; 8. The 68th Street Dump Superfund Site in Maryland; 9. The Maryland Sand.... The Reclamation Oil Company Site in Michigan; 16. The Rose Township Dump Superfund Site in Michigan; 17. The Springfield Township Dump Superfund Site in Michigan; 18. The Ventron/Velsicol Superfund Site...

Solar UV Degradation Patterns in Photodegradable Ldpe

NASA Astrophysics Data System (ADS)

Andrady, A. L.

2016-02-01

"Degradable" polymers have been proposed as an alternative to traditional polymers as a means to potentially reduce the amount and impacts of plastic marine debris, yet the degradation of these materials in seawater is typically unknown. The light-induced degradation of a copolymer of ethylene - carbon monoxide {1%} was studied under accelerated laboratory exposure conditions. The copolymer, used as a substitute for LDPE in some applications where rapid photodegradation is desirable, loses mechanical integrity and embrittles rapidly under outdoor exposure. A laboratory weathering study of these laminates was carried out to compare the kinetics of degradation on sand to those in seawater at ambient temperature, based on the rate of change in tensile properties of the material. Virgin resin pellets of the copolymer were also exposed to laboratory weathering to detect the generation of microparticles at their surface during extensive degradation. Microparticle generation, detected by laser light scattering, as a function of the exposure duration will also be discussed.

Does autophagy work in synaptic plasticity and memory?

PubMed

Shehata, Mohammad; Inokuchi, Kaoru

2014-01-01

Many studies have reported the roles played by regulated proteolysis in neural plasticity and memory. Within this context, most of the research focused on the ubiquitin-proteasome system and the endosome-lysosome system while giving lesser consideration to another major protein degradation system, namely, autophagy. Although autophagy intersects with many of the pathways known to underlie synaptic plasticity and memory, only few reports related autophagy to synaptic remodeling. These pathways include PI3K-mTOR pathway and endosome-dependent proteolysis. In this review, we will discuss several lines of evidence supporting a physiological role of autophagy in memory processes, and the possible mechanistic scenarios for how autophagy could fulfill this function.

Seawater quality assessment and identification of pollution sources along the central coastal area of Gabes Gulf (SE Tunisia): Evidence of industrial impact and implications for marine environment protection.

PubMed

El Zrelli, Radhouan; Rabaoui, Lotfi; Ben Alaya, Mohsen; Daghbouj, Nabil; Castet, Sylvie; Besson, Philippe; Michel, Sylvain; Bejaoui, Nejla; Courjault-Radé, Pierre

2018-02-01

Temperature, pH and trace elements (F, P, Cr, Cu, Zn, Cd, and Pb) contents were determined in 16 stations as well as in 2 industrial and 2 domestic discharge sources, in the central coastal area of the Gulf of Gabes. Compared to the northern and southern areas of the study area, the highest contents of contaminants were reached in the central area which hosts the coastal industrial complex. The seawater in this central area was also found to be acid and of higher temperature. Based on the Water Pollution Index results, an increasing degradation gradient of the seawater quality was revealed from northern and/or southern stations to central ones, categorized as 'strongly to seriously affected'. Phosphogypsum wastes dumped by the Tunisian Chemical Group (GCT) seem to have continuously degraded the seawater quality in the study area. A rapid intervention is needed to stop the effects on the marine environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Friction riveting as an alternative mechanical fastening to join engineering plastics

NASA Astrophysics Data System (ADS)

Gagliardi, Francesco; Conte, Romina; Bentrovato, Renato; Simeoli, Giorgio; Russo, Pietro; Ambrogio, Giuseppina

2018-05-01

Friction Rivecting is a quite new joining process to connect multi-material structures. In brief, a metallic rivet is dipped rotating inside matrixes, usually made of plastics, increasing its original diameter. The use of high-performance plastics is more suitable being their higher mechanical and thermal properties important to avoid material degradation and to allow strong part connections. High-speed friction welding system has been usually used to perform the process. In the work here proposed, the joints have been achieved by means of a traditional milling machine and the attention has been focused on a widely used engineering plastic, i.e. polyamide 6 (PA6) with and without glass fiber reinforcement. A specific speed multiplier has been attached into the mandrel of the used machine to increase the reachable rotational speed. Moreover, rivets made of Titanium Grade 2 and of an Aluminum Alloy, the AA-6060, are utilized. The influence that the heating and the forging length can have on the quality of the obtained junctions, considering a fixed joining depth, has been tested and investigated. The performed connections have been judged by tensile tests, which were set to quantify the maximum strength of the joints for a transverse speed of 1,0 mm/min. Barreling effect can be observed close to the tip, which loses the initial shape of a cylinder characterized by straight vertical walls. Finally, the possible degradation of the polymer, due to temperature increment, has been also evaluated close to the working zone. According to that, it has to be highlighted that the process needs a heating balance, which is necessary to get sound joints. The compromise has, on one side, to allow the rivet penetration and deformation, and on the other side, to avoid the degradation of the polymer, which would affect its properties and a proper rivet deformation.

21 CFR 878.4480 - Absorbable powder for lubricating a surgeon's glove.

Code of Federal Regulations, 2010 CFR

2010-04-01

... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878... degradation. (b) Classification. Class III. (c) Date PMA or notice of completion of a PDP is required. As of...

Vinyl Monomers Double as UV Stabilizers: 179th ACS Meeting Houston.

ERIC Educational Resources Information Center

Chemical and Engineering News, 1980

1980-01-01

Synthesis and polymerization of vinyl monomers that double as stabilizers against degradation of plastics by ultraviolet light has been accomplished. Potential applications include protection of photovoltaic cells in solar power plants. (Author/RE)

The influence of electron-beam irradiation on the chemical and the structural properties of medical-grade polyurethane

NASA Astrophysics Data System (ADS)

Shin, Sukyoung; Lee, Soonhyouk

2015-07-01

Thermo plastic polyurethane (TPU) provides excellent bio-compatibility, flexibility and good irradiation resistance; however, extremely high irradiation doses can alter the structure and the function of macromolecules, resulting in oxidation, chain scission and cross-linking. In this study, the effects of e-beam irradiation on the medical-grade thermo plastic polyurethane were studied. Changes in the chain length and their distribution, as well as changes in the molecular structure were studied. The GPC (gel permeation chromatography) results show that the oxidative decomposition is followed by a decrease in the molecular mass and an increase in polydispersity. This indicates a very inhomogeneous degradation, which is a consequence of the specific course and of the intensity of oxidative degradation. This was confirmed by means of mechanical property measurements. Overall, this study demonstrated that medical-grade TPU was affected by radiation exposure, particularly at high irradiation doses.

Endoluminal Revision (OverStitch (TM) , Apollo Endosurgery) of the Dilated Gastroenterostomy in Patients with Late Dumping Syndrome After Proximal Roux-en-Y Gastric Bypass.

PubMed

Stier, Christine; Chiappetta, Sonja

2016-08-01

Dumping syndrome is a long-term postoperative complication of Roux-en-Y gastric bypass procedures. Morphologically, dumping syndrome usually correlates with a dilatation of the gastroenterostomy with accelerated pouch emptying. Conservative therapy includes diet changes, complementary pharmacotherapy and, if symptoms persist, surgical revision. Surgical options include endoscopic, endoluminal surgery to constrict the gastrojejunostomy using a novel endoscopic suturing device (OverStitch(TM), Apollo). In our study, we aimed to assess the viability, safety and efficacy of this procedure in patients with late dumping; 14 patients who had developed late dumping syndrome underwent surgery using an endoscopic suturing technique (OverStitch(TM), Apollo). Late dumping was confirmed by Sigstad score and an oral glucose tolerance test (OGTT). Prior to surgery, objective analysis of pouch emptying speed was assessed by gastric scintigraphy. Surgery was performed under general anaesthesia. None of the 14 patients suffered intra- or postoperative complications. No postsurgical increase in inflammation parameters was observed. The postinterventional pain scale (visual analogue scale) showed a mean score of 0.5 (range 0-10). In 13 of the 14 patients, no dumping was observed 1-month postsurgery. The postoperative Sigstad score (3.07 ± 2.06; range 1-9) showed an impressive reduction compared with the preoperative score (12.71 ± 4.18; range 7-24) (p < 0.001). Postoperative upper gastrointestinal gastrografin swallow revealed regular emptying in all the patients. The endoluminal endoscopic suturing technique-applied here for surgical revision of gastroenterostomy following Roux-en-Y gastric bypass-represents a promising, novel therapeutic option in late dumping syndrome involving minimal trauma and offering rapid reconvalescence.

Dump system concepts for the Future Circular Collider

NASA Astrophysics Data System (ADS)

Bartmann, W.; Atanasov, M.; Barnes, M. J.; Borburgh, J.; Burkart, F.; Goddard, B.; Kramer, T.; Lechner, A.; Ull, A. Sanz; Schmidt, R.; Stoel, L. S.; Ostojic, R.; Rodziewicz, J.; van Trappen, P.; Barna, D.

2017-03-01

The Future Circular Collider (FCC-hh) beam dump system must provide a safe and reliable extraction and dilution of the stored beam onto a dump absorber. Energy deposition studies show that damage limits of presently used absorber materials will already be reached for single bunches at 50 TeV. A fast field rise of the extraction kicker is required in order to sufficiently separate swept single bunches on the extraction protection absorbers in case of an asynchronous beam dump. In line with this demand is the proposal of a highly segmented extraction kicker system which allows for accepting a single kicker switch erratic and thus, significantly reduces the probability of an asynchronous beam dump. Superconducting septa are foreseen to limit the overall system length and power consumption. Two extraction system concepts are presented and evaluated regarding overall system length, energy deposition on absorbers, hardware requirements, radiation issues, and layout flexibility.

Remote sensing and laboratory techniques for monitoring ocean dumping

NASA Technical Reports Server (NTRS)

Ohlhorst, C. W.; Johnson, R. W.; Meyer, E. R.

1977-01-01

Results of field experiments conducted in the Atlantic Coastal Zone indicate that plumes resulting from ocean dumping of acid waste and sewage sludge have distinguishable spectral characteristics when the radiance of the pollutant is normalized (ratioed to) background ocean water. Acid waste spectra peak between 550-650 nm while sewage sludge spectra have peak values at wavelengths of about 700 nm or greater. Results indicate that identification of acid waste and sewage sludge plumes may be independent of geographical location in the Atlantic Coastal Zone. Radiance ratio curves obtained in the laboratory qualitatively agree with those obtained from field experiments. Results from the July 25, 1977, Galveston Deep Ocean Dump Site experiment show the radiance ratio curve of the biodigested industrial waste to be fairly flat and similar to the radiance ratio curves of sewage sludge line dumps and sewage sludge spot dumps that have been in the water for several hours.

Application of remote sensing to monitoring and studying dispersion in ocean dumping

NASA Technical Reports Server (NTRS)

Johnson, R. W.; Ohlhorst, C. W.

1981-01-01

Remotely sensed wide area synoptic data provides information on ocean dumping that is not readily available by other means. A qualitative approach has been used to map features, such as river plumes. Results of quantitative analyses have been used to develop maps showing quantitative distributions of one or more water quality parameters, such as suspended solids or chlorophyll a. Joint NASA/NOAA experiments have been conducted at designated dump areas in the U.S. coastal zones to determine the applicability of aircraft remote sensing systems to map plumes resulting from ocean dumping of sewage sludge and industrial wastes. A second objective is related to the evaluation of previously developed quantitative analysis techniques for studying dispersion of materials in these plumes. It was found that plumes resulting from dumping of four waste materials have distinctive spectral characteristics. The development of a technology for use in a routine monitoring system, based on remote sensing techniques, is discussed.

Selected Black-Coal Mine Waste Dumps in the Ostrava-Karviná Region: An Analysis of Their Potential Use

NASA Astrophysics Data System (ADS)

Niemiec, Dominik; Duraj, Miloš; Cheng, Xianfeng; Marschalko, Marian; Kubáč, Jan

2017-12-01

The paper aims to analyse the options for the use of selected black-coal mine waste dump bodies in the Ostrava-Karviná Region. In the Czech Republic there are approximately 70 mine waste dumps, out of which 50 are located in the Ostrava-Karviná Coal District. The issue is highly topical, particularly in the region, because the dump bodies significantly affect the landscape character of the Ostrava-Karviná Region and pose ecological risks. In such cases, their redevelopment and land reclamation are not easy either from the environmental or economic points of view. It is clear that the redevelopment of such geological environment is difficult, and it is vital to make the right decisions as for what purposes the mine waste dumps should be used. Next, it is important to take into account all the economic and environmental aspects of the locality in question.

The influence of temperature on the formation of liquid fuel from Polypropylene plastic wastes

NASA Astrophysics Data System (ADS)

Martynis, M.; Mulyazmi; Praputri, E.; Witri, R.; Putri, N.

2018-03-01

The current trend of municipal waste management in urban areas is caused by rapid changes in social, economic, political and cultural life. As a non-biodegradable polymers that have become essential materials, plastic wastes have created a very serious environmental challenge because of the huge quantities and their disposal problems. Recycling of plastics is seen as one method for reducing environmental and resource depletion. The most attractive technique of plastics recycling is pyrolysis involving the degradation of the polymeric materials by heating in the absence of oxygen. This study investigated the characteristics of pyrolysis liquid fuel (PLF) produced from polypropylene plastic wastes with temperature variations. Pyrolisis was carried out on 200 grams of polypropylene waste plastics at the operating temperature of 200°C, 250°C, 300 °C and 350 °C for 45 minutes. The liquid products were found to have carbon chain length in the range of C8-C9, similar with gasoline. The maximum density, volume and calorific value of the oil obtained were 0.8 g/cm3, 61 ml and 1307 cal/gr, respectively.

Mid-infrared picosecond pump-dump-probe and pump-repump-probe experiments to resolve a ground-state intermediate in cyanobacterial phytochrome Cph1.

PubMed

van Wilderen, Luuk J G W; Clark, Ian P; Towrie, Michael; van Thor, Jasper J

2009-12-24

Multipulse picosecond mid-infrared spectroscopy has been used to study photochemical reactions of the cyanobacterial phytochrome photoreceptor Cph1. Different photophysical schemes have been discussed in the literature to describe the pathways after photoexcitation, particularly, to identify reaction phases that are linked to photoisomerisation and electronic decay in the 1566-1772 cm(-1) region that probes C=C and C=O stretching modes of the tetrapyrrole chromophore. Here, multipulse spectroscopy is employed, where, compared to conventional visible pump-mid-infrared probe spectroscopy, an additional visible pulse is incorporated that interacts with populations that are evolving on the excited- and ground-state potential energy surfaces. The time delays between the pump and the dump pulse are chosen such that the dump pulse interacts with different phases in the reaction process. The pump and dump pulses are at the same wavelength, 640 nm, and are resonant with the Pr ground state as well as with the excited state and intermediates. Because the dump pulse additionally pumps the remaining, partially recovered, and partially oriented ground-state population, theory is developed for estimating the fraction of excited-state molecules. The calculations take into account the model-dependent ground-state recovery fraction, the angular dependence of the population transfer resulting from the finite bleach that occurs with linearly polarized intense femtosecond optical excitation, and the partially oriented population for the dump field. Distinct differences between the results from the experiments that use a 1 or a 14 ps dump time favor a branching evolution from S1 to an excited state or reconfigured chromophore and to a newly identified ground-state intermediate (GSI). Optical dumping at 1 ps shows the instantaneous induced absorption of a delocalized C=C stretching mode at 1608 cm(-1), where the increased cross section is associated with the electronic ground-state structure of the ZZZ configuration of the linear tetrapyrrole chromophore. The dump-induced absorption decays with time constants of 5 and 19 ps to the Pr ground state. Employing a dump pulse at 14 ps results in an instantaneous decrease of the absorption of the 1608 cm(-1) band, indicating repumping of the GSI. The dump-induced absorption recovers back to the GSI with a 6 ps lifetime. A spectral similarity is observed between the 6 ps phase in the dump experiment and the 3 ps component found in the two-pulse pump-probe measurement. Combined with the dominance of ground-state absorption bands in the dump-induced spectrum, this indicates the presence of a GSI, which is additionally characterized by previously unidentified induced absorption at 1710 and 1570-80 cm(-1). The metastable photoproduct Lumi-R, which is in the electronic ground state and populated at 500 ps after excitation of Pr, is highly efficiently repumped into the Pr ground state with the power density used. After repumping, Lumi-R is not recovered on the 500 ps time scale of the experiment and is distinct from the GSI of Pr since it is not associated with its characteristic induced absorption at 1710 and 1570-80 cm(-1).

Properties of a bacterium which degrades solid poly(tetramethylene succinate)-co-adipate, a biodegradable plastic.

PubMed

Uchida, H; Nakajima-Kambe, T; Shigeno-Akutsu, Y; Nomura, N; Tokiwa, Y; Nakahara, T

2000-08-01

Various microorganisms were screened for their ability to degrade poly(tetramethylene succinate)-co-(tetramethylene adipate) (PBSA). Strain BS-3, which was newly isolated from a soil sample, was selected as the best strain. From taxonomical studies, the strain was tentatively ascribed to belong to the genus Acidovorax, most probably to the species A. delafieldii. Strain BS-3 could degrade both solid and emulsified PBSA, and also emulsified poly(tetramethylene succinate). During the degradation, a lipase activity was observed in the culture broth. This lipase activity was induced more strongly by PBSA than by tributyrin or triolein which are typical substrates of lipase. These observations strongly suggest that this lipase was involved in the PBSA biodegradation in strain BS-3.

Biodegradation and Mineralization of Polystyrene by Plastic-Eating Mealworms: Part 2. Role of Gut Microorganisms.

PubMed

Yang, Yu; Yang, Jun; Wu, Wei-Min; Zhao, Jiao; Song, Yiling; Gao, Longcheng; Yang, Ruifu; Jiang, Lei

2015-10-20

The role of gut bacteria of mealworms (the larvae of Tenebrio molitor Linnaeus) in polystyrene (PS) degradation was investigated. Gentamicin was the most effective inhibitor of gut bacteria among six antibiotics tested. Gut bacterial activities were essentially suppressed by feeding gentamicin food (30 mg/g) for 10 days. Gentamicin-feeding mealworms lost the ability to depolymerize PS and mineralize PS into CO2, as determined by characterizing worm fecula and feeding with (13)C-labeled PS. A PS-degrading bacterial strain was isolated from the guts of the mealworms, Exiguobacterium sp. strain YT2, which could form biofilm on PS film over a 28 day incubation period and made obvious pits and cavities (0.2-0.3 mm in width) on PS film surfaces associated with decreases in hydrophobicity and the formation of C-O polar groups. A suspension culture of strain YT2 (10(8) cells/mL) was able to degrade 7.4 ± 0.4% of the PS pieces (2500 mg/L) over a 60 day incubation period. The molecular weight of the residual PS pieces was lower, and the release of water-soluble daughter products was detected. The results indicated the essential role of gut bacteria in PS biodegradation and mineralization, confirmed the presence of PS-degrading gut bacteria, and demonstrated the biodegradation of PS by mealworms.

Validation of ATR FT-IR to identify polymers of plastic marine debris, including those ingested by marine organisms.

PubMed

Jung, Melissa R; Horgen, F David; Orski, Sara V; Rodriguez C, Viviana; Beers, Kathryn L; Balazs, George H; Jones, T Todd; Work, Thierry M; Brignac, Kayla C; Royer, Sarah-Jeanne; Hyrenbach, K David; Jensen, Brenda A; Lynch, Jennifer M

2018-02-01

Polymer identification of plastic marine debris can help identify its sources, degradation, and fate. We optimized and validated a fast, simple, and accessible technique, attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR), to identify polymers contained in plastic ingested by sea turtles. Spectra of consumer good items with known resin identification codes #1-6 and several #7 plastics were compared to standard and raw manufactured polymers. High temperature size exclusion chromatography measurements confirmed ATR FT-IR could differentiate these polymers. High-density (HDPE) and low-density polyethylene (LDPE) discrimination is challenging but a clear step-by-step guide is provided that identified 78% of ingested PE samples. The optimal cleaning methods consisted of wiping ingested pieces with water or cutting. Of 828 ingested plastics pieces from 50 Pacific sea turtles, 96% were identified by ATR FT-IR as HDPE, LDPE, unknown PE, polypropylene (PP), PE and PP mixtures, polystyrene, polyvinyl chloride, and nylon. Published by Elsevier Ltd.

75 FR 44251 - Proposed Administrative Settlement Agreement Under Section 122 of the Comprehensive Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-28

... Dump No. 5 Site Located in Jersey City, Hudson County, NJ AGENCY: Environmental Protection Agency... response costs incurred by EPA at the Turnpike Dump No. 5 Site (``Site'') located in Jersey City, Hudson... reference the Turnpike Dump No. 5 Site, EPA Index No. II-CERCLA-02-2010-2015 and should be sent to the U.S...

Orbiter Water Dump Nozzles Redesign Lessons Learned

NASA Technical Reports Server (NTRS)

Rotter, Hank

2017-01-01

Hank Rotter, NASA Technical Fellow for Environmental Control and Life Support System, will provide the causes and lessons learned for the two Space Shuttle Orbiter water dump icicles that formed on the side of the Orbiter. He will present the root causes and the criticality of these icicles, along with the redesign of the water dump nozzles and lessons learned during the redesign phase.

Environmental Improvement Of Opencast Mining

NASA Astrophysics Data System (ADS)

Prokopenko, S.; Sushko, A.; Filatov, Yu; Kislyakov, M.; Kislyakov, I.

2017-01-01

Existing classifications of waste dumps in the quarries are given and their phenomenological nature is clarified. The need to identify the essence of the term "dump" is shown as well as the idea of "dump" as an artificial formation with everted and mixed rocks distanced from the quarry. Essential classification of man-made rock formations in quarries is developed. Characteristic of variations of man-made waste formations in quarries is developed. To reduce harmful effects of open-pit mining, dumps should be substituted with strat-lays - man-made structures relevant to natural stratification of litho-substances. Construction of strat-lays would improve ecological and technological culture of open cast mining.

SPIDER beam dump as diagnostic of the particle beam

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

Zaupa, M., E-mail: matteo.zaupa@igi.cnr.it; Sartori, E.; Consorzio RFX, Corso Stati Uniti 4, Padova 35127

The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography andmore » beam emission spectroscopy.« less

Slope Stability Analysis of Waste Dump in Sandstone Open Pit Osielec

NASA Astrophysics Data System (ADS)

Adamczyk, Justyna; Cała, Marek; Flisiak, Jerzy; Kolano, Malwina; Kowalski, Michał

2013-03-01

This paper presents the slope stability analysis for the current as well as projected (final) geometry of waste dump Sandstone Open Pit "Osielec". For the stability analysis six sections were selected. Then, the final geometry of the waste dump was designed and the stability analysis was conducted. On the basis of the analysis results the opportunities to improve the stability of the object were identified. The next issue addressed in the paper was to determine the proportion of the mixture containing mining and processing wastes, for which the waste dump remains stable. Stability calculations were carried out using Janbu method, which belongs to the limit equilibrium methods.

SPIDER beam dump as diagnostic of the particle beam

NASA Astrophysics Data System (ADS)

Zaupa, M.; Dalla Palma, M.; Sartori, E.; Brombin, M.; Pasqualotto, R.

2016-11-01

The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab: an update on PR12-16-001

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

Battaglieri, M.

This document is an update to the proposal PR12-16-001 Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab submitted to JLab-PAC44 in 2016 reporting progress in addressing questions raised regarding the beam-on backgrounds. The concerns are addressed by adopting a new simulation tool, FLUKA, and planning measurements of muon fluxes from the dump with its existing shielding around the dump. First, we have implemented the detailed BDX experimental geometry into a FLUKA simulation, in consultation with experts from the JLab Radiation Control Group. The FLUKA simulation has been compared directly to our GEANT4 simulations and shown to agreemore » in regions of validity. The FLUKA interaction package, with a tuned set of biasing weights, is naturally able to generate reliable particle distributions with very small probabilities and therefore predict rates at the detector location beyond the planned shielding around the beam dump. Second, we have developed a plan to conduct measurements of the muon ux from the Hall-A dump in its current configuration to validate our simulations.« less

Monitoring and sustainable management of oil polluting wrecks and chemical munitions dump sites in the Baltic Sea

NASA Astrophysics Data System (ADS)

Hassellöv, Ida-Maja; Tengberg, Anders

2017-04-01

The Baltic Sea region contains a dark legacy of about 100 000 tons of dumped chemical warfare agents. As time passes the gun shells corrode and the risks of release of contaminants increase. A major goal of the EU-flagship project Daimon is to support governmental organisations with case-to-case adapted methods for sustainable management of dumped toxic munitions. At the Chalmers University of Technology, a partner of Daimon, a unique ISO 31000 adapted method was developed to provide decision support regarding potentially oilpolluting shipwrecks. The method is called VRAKA and is based on probability calculations. It includes site-specific information as well as expert knowledge. VRAKA is now being adapted to dumped chemical munitions. To estimate corrosion potential of gun shells and ship wrecks along with sediment re-suspension and transport multiparameter instruments are deployed at dump sites. Parameters measured include Currents, Salinity, Temperature, Oxygen, Depth, Waves and Suspended particles. These measurements have revealed how trawling at dump sites seems to have large implications in spreading toxic substances (Arsenic) over larger areas. This presentation will shortly describe the decision support model, the used instrumentation and discuss some of the obtain results.

Mobilization and transport of pollutants in an abandoned dump in tropical conditions

NASA Astrophysics Data System (ADS)

Pelinson, Natalia; Shinzato, Marjolly; Wendland, Edson

2017-04-01

The valuation and treatment techniques of municipal solid waste (MSW) in developing countries are not sufficiently developed, and therefore, the volume of waste destined for disposal still presents significant amounts. In Brazil, the more common practice of final destination is the deposition on the soil, due to its simple operation and low cost compared to other techniques. One of the most serious negative environmental impacts in the irregular disposal of solid waste is the contamination of soil and groundwater by waste leachates. The final disposal in dumps is forbidden by Brazilian law since 2010, nevertheless, the public administration is not prepared to monitor waste disposal areas and the risk of contamination of water. In this sense, a research has been developed in an abandoned dump installed over an outcrop of the Botucatu Formation, which is part of the Guarani Aquifer System (SAG) and therefore, is an area of high water vulnerability. In this dump, an old gully was used as a final waste disposal area for urban, construction and demolition, medical and industrial waste from 1980 to 1996. Since the end of the deposition, the waste body is kept with inefficient hydraulic control. The water infiltration due to rainfall promotes the mobility of contaminant in the deposit. The present water quality in the dump has been monitored through physical and chemical analysis of samples collected in the unsaturated zone (inside the waste mass using vacuum lysimeters) and in the saturated zone (monitoring wells). The rainfall variation observed in the years 2014 (dry year) and 2015 (wet year) contributed significantly to evaluate the mobilization of pollutants within the dump. The reduction of the water volume that infiltrates the waste mass affected the quality of the leachate collected in the lysimeters. The groundwater collected in monitoring wells outside the dump area presents low turbidity values (<1.50 NTU) in relation to wells located downstream of the dump showed values greater than 10, a similar behavior was observed for the conductivity (>1000 µS.cma-1 in leachate) and chlorides values (>800 mg.L-1). Contaminated water flows through the bottom of the dump. In addition, this research also indicates amendments of surface water downstream of the dump area.

Assessment of nonpoint source chemical loading potential to watersheds containing uranium waste dumps associated with uranium exploration and mining, San Rafael Swell, Utah

USGS Publications Warehouse

Freeman, Michael L.; Naftz, David L.; Snyder, Terry; Johnson, Greg

2008-01-01

During July and August of 2006, 117 solid-phase samples were collected from abandoned uranium waste dumps, geologic background sites, and adjacent streambeds in the San Rafael Swell, in southeastern Utah. The objective of this sampling program was to assess the nonpoint source chemical loading potential to ephemeral and perennial watersheds from uranium waste dumps on Bureau of Land Management property. Uranium waste dump samples were collected using solid-phase sampling protocols. After collection, solid-phase samples were homogenized and extracted in the laboratory using a field leaching procedure. Filtered (0.45 micron) water samples were obtained from the field leaching procedure and were analyzed for Ag, As, Ba, Be, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, U, V, and Zn at the Inductively Coupled Plasma-Mass Spectrometry Metals Analysis Laboratory at the University of Utah, Salt Lake City, Utah and for Hg at the U.S. Geological Survey National Water Quality Laboratory, Denver, Colorado. For the initial ranking of chemical loading potential of suspect uranium waste dumps, leachate analyses were compared with existing aquatic life and drinking-water-quality standards and the ratio of samples that exceeded standards to the total number of samples was determined for each element having a water-quality standard for aquatic life and drinking-water. Approximately 56 percent (48/85) of the leachate samples extracted from uranium waste dumps had one or more chemical constituents that exceeded aquatic life and drinking-water-quality standards. Most of the uranium waste dump sites with elevated trace-element concentrations in leachates were along Reds Canyon Road between Tomsich Butte and Family Butte. Twelve of the uranium waste dump sites with elevated trace-element concentrations in leachates contained three or more constituents that exceeded drinking-water-quality standards. Eighteen of the uranium waste dump sites had three or more constituents that exceeded trace-element concentrations for aquatic life water-quality standards. The proximity of the uranium waste dumps in the Tomsich Butte area near Muddy Creek, coupled with the elevated concentration of trace elements, increases the offsite impact potential to water resources. Future assessment and remediation priority of these areas may be done by using GIS-based risk-mapping techniques, such as Sensitive Catchment Integrated Mapping and Analysis Project.

Inhibitors of oxidative and hydrolytic endocannabinoid degradation do not enhance depolarization-induced suppression of excitation on dorsal cochlear nucleus glycinergic neurons.

PubMed

Zugaib, João; Leão, Ricardo M

2017-04-01

Neurons from the dorsal cochlear nucleus (DCN) present endocannabinoid (EC) dependent short-term synaptic plasticity in the form of depolarization-induced suppression of excitation (DSE). Postsynaptic calcium influx promotes EC synthesis and depression of neurotransmission. ECs can be degraded by a hydrolytic and an oxidative pathway, the latter via the enzyme cyclooxygenase 2 (COX-2). Hyperactivity in the DCN is related to the development of tinnitus, which can be induced by high doses of salicylate, a COX-2 inhibitor. Since EC-dependent plasticity in the DCN can affect its excitation-inhibition balance, we investigated the impact of inhibitors of both oxidative and hydrolytic EC metabolism on the DSE from the synapses between the parallel fibers and cartwheel neurons (PF-CW) in the DCN. We found that inhibitors of COX-2 (ibuprofen and indomethacin) did not alter DSE at the PF-CW synapse. Salicylate also did not alter DSE. However, we found that inhibitors of the hydrolytic pathway did not affect DSE magnitude, but surprisingly speeded DSE decay. We conclude that oxidative EC degradation in the PF-CW synapse is not relevant for termination of DSE and are probably not important for controlling this form of synaptic plasticity in the DCN PF-CW synapse. The lack of effect on DSE of high doses of salicylate also suggests that it is not acting by increasing DSE in the PF-CWC synapse. However, the counter intuitive effect of the hydrolytic inhibitors shows that increasing EC on this synapse have more complex effects on DSE. © 2016 Wiley Periodicals, Inc.

Adaptive plasticity in speech perception: Effects of external information and internal predictions.

PubMed

Guediche, Sara; Fiez, Julie A; Holt, Lori L

2016-07-01

When listeners encounter speech under adverse listening conditions, adaptive adjustments in perception can improve comprehension over time. In some cases, these adaptive changes require the presence of external information that disambiguates the distorted speech signals, whereas in other cases mere exposure is sufficient. Both external (e.g., written feedback) and internal (e.g., prior word knowledge) sources of information can be used to generate predictions about the correct mapping of a distorted speech signal. We hypothesize that these predictions provide a basis for determining the discrepancy between the expected and actual speech signal that can be used to guide adaptive changes in perception. This study provides the first empirical investigation that manipulates external and internal factors through (a) the availability of explicit external disambiguating information via the presence or absence of postresponse orthographic information paired with a repetition of the degraded stimulus, and (b) the accuracy of internally generated predictions; an acoustic distortion is introduced either abruptly or incrementally. The results demonstrate that the impact of external information on adaptive plasticity is contingent upon whether the intelligibility of the stimuli permits accurate internally generated predictions during exposure. External information sources enhance adaptive plasticity only when input signals are severely degraded and cannot reliably access internal predictions. This is consistent with a computational framework for adaptive plasticity in which error-driven supervised learning relies on the ability to compute sensory prediction error signals from both internal and external sources of information. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Adaptive plasticity in speech perception: effects of external information and internal predictions

PubMed Central

Guediche, Sara; Fiez, Julie A.; Holt, Lori L.

2016-01-01

When listeners encounter speech under adverse listening conditions, adaptive adjustments in perception can improve comprehension over time. In some cases, these adaptive changes require the presence of external information that disambiguates the distorted speech signals, whereas in other cases mere exposure is sufficient. Both external (e.g. written feedback) and internal (e.g., prior word knowledge) sources of information can be used to generate predictions about the correct mapping of a distorted speech signal. We hypothesize that these predictions provide a basis for determining the discrepancy between the expected and actual speech signal that can be used to guide adaptive changes in perception. This study provides the first empirical investigation that manipulates external and internal factors through 1) the availability of explicit external disambiguating information via the presence or absence of post-response orthographic information paired with a repetition of the degraded stimulus, and 2) the accuracy of internally-generated predictions; an acoustic distortion is introduced either abruptly or incrementally. The results demonstrate that the impact of external information on adaptive plasticity is contingent upon whether the intelligibility of the stimuli permits accurate internally-generated predictions during exposure. External information sources enhance adaptive plasticity only when input signals are severely degraded and cannot reliably access internal predictions. This is consistent with a computational framework for adaptive plasticity in which error-driven supervised learning relies on the ability to compute sensory prediction error signals from both internal and external sources of information. PMID:26854531

Functionalized hexagonal boron nitride nano-coatings for protection of transparent plastics

NASA Astrophysics Data System (ADS)

Van Tran, Thu; Usta, Aybala; Asmatulu, Ramazan

2016-04-01

Nanocoating is the result of a coating application of nanomaterials to build a consistent network of molecules in a paint to protect the surfaces of various materials and devices. Hexagonal Boron Nitride (h-BN) is in two dimensional form with excellent thermal, mechanical and chemical properties. These BN nanocoatings are also a thermally insulating material for heat management. After adding functionalized h-BNs into paints or other coatings, they will absorb the harmful UV part of sunlight and prevent coating against the environmental degradations. The impacts of the environmental factors on the coatings can be substantially eliminated. In the present study, h-BNs were modified with [2-(2-Aminoethylamino) propyl] trimethoxysilane and uniformly dispersed into the polyurethane coatings with different amounts, such as 0.1, 0.2, 0.4, and 0.8wt% to increase hardness and water resistance, and decrease the UV degradation level of coatings and transparent plastics. The prepared samples were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), UV-Vis Spectroscopy, Scanning Electron Microscope (SEM), Water Contact Angle, and Differential Scanning Calorimeter (DSC). The test results showed that the nanocoatings with functionalized h-BN provided excellent physical and chemical behaviors against the UV and other physical degradations on the substrates.

Mechanical and degradation properties of biodegradable Mg strengthened poly-lactic acid composite through plastic injection molding.

PubMed

Butt, Muhammad Shoaib; Bai, Jing; Wan, Xiaofeng; Chu, Chenglin; Xue, Feng; Ding, Hongyan; Zhou, Guanghong

2017-01-01

Full biodegradable magnesium alloy (AZ31) strengthened poly-lactic acid (PLA) composite rods for potential application for bone fracture fixation were prepared by plastic injection process in this work. Their surface/interfacial morphologies, mechanical properties and vitro degradation were studied. In comparison with untreated Mg rod, porous MgO ceramic coating on Mg surface formed by Anodizing (AO) and micro-arc-oxidation (MAO)treatment can significantly improve the interfacial binding between outer PLA cladding and inner Mg rod due to the micro-anchoring action, leading to better mechanical properties and degradation performance of the composite rods.With prolonging immersion time in simulated body fluid (SBF) solution until 8weeks, the MgO porous coating were corroded gradually, along with the disappearance of original pores and the formation of a relatively smooth surface. This resulted in a rapidly reduction in mechanical properties for corresponding composite rods owing to the weakening of interfacial binding capacity. The present results indicated that this new PLA-clad Mg composite rods show good potential biomedical applications for implants and instruments of orthopedic inner fixation. Copyright © 2016 Elsevier B.V. All rights reserved.

Protein-based composites and biomaterials

USDA-ARS?s Scientific Manuscript database

World industrialization has generated substantial quantities of petroleum-based plastics over many years, which are not biodegradable or compostable, and are permanently residing on land, in landfills, or in the oceans, as environmental pollution. Recently, total or partially degradable materials ha...

[Application of biodegradable plastic film to reduce plastic film residual pollution in Chinese agriculture].

PubMed

Yan, Changrong; He, Wenqing; Xue, Yinghao; Liu, Enke; Liu, Qin

2016-06-25

Plastic film has become an important agriculture production material in recent years. Over the past three decades, the amount and application area of plastic film have increased steadily, and in 2014, which are 1.4 million tons and more than 180 million hm² respectively. It plays a key role for ensuring the supply of agricultural goods in China. Meanwhile, plastic film residual pollution becomes more and more serious, and in some regions, the amount of plastic film residues has reached over 250 kg/hm². In part of the Northwest region, soil structure of farmland has been destroyed by plastic film residues and then crop growth and farming operations were suppressed. It is recognized as a good choice to replace plastic film with biodegradable plastic film, an effective measure to solve the plastic film residue pollution. Now, it is in a critical stage of study and assessment of biodegradable plastic film in China and fortunately some biodegradable plastic films show effects in the production of potatoes, peanuts and tobacco. Overall, a series of challenges has still been faced by the biodegradable plastic film, mainly including improving the quality of biodegradable plastic products, such as tensile strength, flexibility, improving the controllability of rupture and degradation, enhancing the ability of increasing soil temperature and preserving soil moisture, and to satisfy the demand of crops production with mulching. In addition, it is essential to reduce the cost of the biodegradable film and promote the application of biodegradable film on large-scale. With the development of biodegradable plastic technology and agricultural production environment, the application of the biodegradable film will have a good future.

Microplastics and Nanoplastics in Aquatic Environments: Aggregation, Deposition, and Enhanced Contaminant Transport.

PubMed

Alimi, Olubukola S; Farner Budarz, Jeffrey; Hernandez, Laura M; Tufenkji, Nathalie

2018-02-20

Plastic litter is widely acknowledged as a global environmental threat, and poor management and disposal lead to increasing levels in the environment. Of recent concern is the degradation of plastics from macro- to micro- and even to nanosized particles smaller than 100 nm in size. At the nanoscale, plastics are difficult to detect and can be transported in air, soil, and water compartments. While the impact of plastic debris on marine and fresh waters and organisms has been studied, the loads, transformations, transport, and fate of plastics in terrestrial and subsurface environments are largely overlooked. In this Critical Review, we first present estimated loads of plastics in different environmental compartments. We also provide a critical review of the current knowledge vis-à-vis nanoplastic (NP) and microplastic (MP) aggregation, deposition, and contaminant cotransport in the environment. Important factors that affect aggregation and deposition in natural subsurface environments are identified and critically analyzed. Factors affecting contaminant sorption onto plastic debris are discussed, and we show how polyethylene generally exhibits a greater sorption capacity than other plastic types. Finally, we highlight key knowledge gaps that need to be addressed to improve our ability to predict the risks associated with these ubiquitous contaminants in the environment by understanding their mobility, aggregation behavior and their potential to enhance the transport of other pollutants.

Fluoxetine increases plasticity and modulates the proteomic profile in the adult mouse visual cortex

PubMed Central

Ruiz-Perera, L.; Muniz, M.; Vierci, G.; Bornia, N.; Baroncelli, L.; Sale, A.; Rossi, F.M.

2015-01-01

The scarce functional recovery of the adult CNS following injuries or diseases is largely due to its reduced potential for plasticity, the ability to reorganize neural connections as a function of experience. Recently, some new strategies restoring high levels of plasticity in the adult brain have been identified, especially in the paradigmatic model of the visual system. A chronic treatment with the anti-depressant fluoxetine reinstates plasticity in the adult rat primary visual cortex, inducing recovery of vision in amblyopic animals. The molecular mechanisms underlying this effect remain largely unknown. Here, we explored fluoxetine effects on mouse visual cortical plasticity, and exploited a proteomic approach to identify possible candidates mediating the outcome of the antidepressant treatment on adult cortical plasticity. We showed that fluoxetine restores ocular dominance plasticity in the adult mouse visual cortex, and identified 31 differentially expressed protein spots in fluoxetine-treated animals vs. controls. MALDITOF/TOF mass spectrometry identification followed by bioinformatics analysis revealed that these proteins are involved in the control of cytoskeleton organization, endocytosis, molecular transport, intracellular signaling, redox cellular state, metabolism and protein degradation. Altogether, these results indicate a complex effect of fluoxetine on neuronal signaling mechanisms potentially involved in restoring plasticity in the adult brain. PMID:26205348

Monitoring the biodegradation of polycyclic aromatic hydrocarbons in a co-contaminated soil using stable isotope labeling

NASA Astrophysics Data System (ADS)

Wawra, Anna; Friesl-Hanl, Wolfgang; Watzinger, Andrea; Soja, Gerhard; Puschenreiter, Markus

2016-04-01

Conventional remediation techniques like "dig and dump" are costly and limited in scale. Plant- and microbe-based alternatives, e.g. phytoremediation options, offer a cheap and environmentally friendly approach that can be applied on larger areas. However, the application of phytoremediation techniques to co-contaminated sites may be hindered due to a potential inhibition of biodegradation processes by the presence of heavy metals in soil. Therefore, the objective of this study is to test the hypothesis that the degradation of organic pollutants can be enhanced by immobilising potentially toxic heavy metals. This study aims to identify the influence of heavy metal immobilisation on the degradation of organic pollutants, and to determine chemical, physical and biological measures further accelerating these processes. The influence of heavy metals on organic pollutant degradation dynamics is assessed using 13C-phospholipid fatty acid analysis (13C-PLFA). Application of 13C-labeled phenanthrene allows the identification of microbial groups responsible for the degradation process. For metal immobilisation and enhanced biodegradation, distinct mineral and organic soil amendments (iron oxides, gravel sludge, biochar) are deployed, partly in combination with fast-growing and pollution-tolerant woody plants (willow, black locust and alder). Results of an incubation batch experiment show a fast degradation of the phenanthrene label within the first two weeks by various microbial groups (gram negative bacteria as indicated by the cy17:0 peak) resulting in a decrease by up to 80% of the total PAH concentration (Σ 16 EPA PAHs) measured in soil. A similar trend was observed in the greenhouse pot experiment, whereby heavy metal accumulation in the woody plants growing on the co-contaminated soil significantly varied with plant species (willow > black locust, alder).

Characterization and engineering of a plastic-degrading aromatic polyesterase

PubMed Central

Austin, Harry P.; Allen, Mark D.; Rorrer, Nicholas A.; Kearns, Fiona L.; Silveira, Rodrigo L.; Pollard, Benjamin C.; Dominick, Graham; El Omari, Kamel; Mykhaylyk, Vitaliy; Michener, William E.; Amore, Antonella; Skaf, Munir S.; Crowley, Michael F.; Thorne, Alan W.; Johnson, Christopher W.; Woodcock, H. Lee

2018-01-01

Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability is a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 Å resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral α/β-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PET replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters. PMID:29666242

Characterization and engineering of a plastic-degrading aromatic polyesterase

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

Austin, Harry P.; Allen, Mark D.; Donohoe, Bryon S.

Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability ismore » a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 A resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral a/..beta..-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PET replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters.« less

Characterization and engineering of a plastic-degrading aromatic polyesterase

DOE PAGES

Austin, Harry P.; Allen, Mark D.; Donohoe, Bryon S.; ...

2018-04-17

Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability ismore » a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 A resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral a/..beta..-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PET replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters.« less

Use of Bisphenol A-containing baby bottles in Cameroon and Nigeria and possible risk management and mitigation measures: community as milestone for prevention.

PubMed

Pouokam, Guy Bertrand; Ajaezi, Godwin Chukwuebuka; Mantovani, Alberto; Orisakwe, Orish Ebere; Frazzoli, Chiara

2014-05-15

The plasticizer Bisphenol A (BPA) is banned in baby bottles in many industrialized countries due to safety concerns. We provide a pilot view on the potential BPA exposure of bottle-fed children in sub-Saharan Africa through an enquiry on availability, accessibility and affordability of plastic baby bottles, usage pattern, and risk perception. An observational survey was conducted in a randomized group of vending sites (34 pharmacies; 87 shops and markets), in three cities (Yaoundé, Foumbot, Bafoussam) in Cameroon (two regions), and in two cities (Lagos, Port Harcourt) in Nigeria (two states). Interviews in vending sites and group discussions were conducted with 248 mothers. Cameroon and Nigeria showed a largely comparable situation. Plastic baby bottles are largely imported from industrialized countries, where a label indicates the presence/absence of BPA. In pharmacies most plastic baby bottles are labeled as BPA-free, whereas most bottles sold in shops are not BPA-free. BPA-containing bottles are more accessible and affordable, due to sale in common shops and lower costs. The meaning of the label BPA-free is unknown to both vendors and customers: the BPA issue is also largely unknown to policy makers and media and no regulation exists on food contact materials. The wide availability of BPA-containing baby bottles, lack of information and usage patterns (e.g. temperature and duration of heating) suggest a likely widespread exposure of African infants. Possible usage recommendations to mitigate exposure are indicated. Risk communication to policy makers, sellers and citizens is paramount to raise awareness and to oppose possible dumping from countries where BPA-containing materials are banned. Our pilot study points out relevant global health issues such as the capacity building of African communities on informed choices and usage of baby products, and the exploitation of international knowledge by African scientists and risk managers. Copyright © 2014 Elsevier B.V. All rights reserved.

78 FR 72639 - Non-Malleable Cast Iron Pipe Fittings From the People's Republic of China: Final Results of the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-03

... dumping margins likely to prevail is indicated in the ``Final Results of Sunset Review'' section of this... likelihood of continuation or recurrence of dumping and the magnitude of the margins likely to prevail if the... dumping margin likely to prevail [FR Doc. 2013-28952 Filed 12-2-13; 8:45 am] BILLING CODE 3510-DS-P ...

76 FR 34014 - Airworthiness Directives; Bombardier, Inc. Model CL-215-1A10, CL-215-6B11 (CL-215T Variant), and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-10

... unsafe condition as: The emergency water dump pulley support bracket assembly, Part Number (P/N) 215-94711-2, has been found cracked or broken on a number of aeroplanes. Failure of the emergency water dump... specified products. The MCAI states: The emergency water dump pulley support bracket assembly, Part Number...

Assessment of nonpoint source chemical loading potential to watersheds containing uranium waste dumps and human health hazards associated with uranium exploration and mining, Red, White, and Fry Canyons, southeastern Utah, 2007

USGS Publications Warehouse

Beisner, Kimberly R.; Marston, Thomas M.; Naftz, David L.; Snyder, Terry; Freeman, Michael L.

2010-01-01

During May, June, and July 2007, 58 solid-phase samples were collected from abandoned uranium mine waste dumps, background sites, and adjacent streambeds in Red, White, and Fry Canyons in southeastern Utah. The objectives of this sampling program were to (1) assess the nonpoint-source chemical loading potential to ephemeral and perennial drainage basins from uranium waste dumps and (2) assess potential effects on human health due to recreational activities on and around uranium waste dumps on Bureau of Land Management property. Uranium waste-dump samples were collected using solid-phase sampling protocols. After collection, solid-phase samples were homogenized and extracted in the laboratory using a leaching procedure. Filtered (0.45 micron) water samples were obtained from the field leaching procedure and were analyzed for major and trace elements at the Inductively Coupled Plasma-Mass Spectrometry Metals Analysis Laboratory at the University of Utah. A subset of the solid-phase samples also were digested with strong acids and analyzed for major ions and trace elements at the U.S. Geological Survey Geologic Division Laboratory in Denver, Colorado. For the initial ranking of chemical loading potential for uranium waste dumps, results of leachate analyses were compared with existing aquatic-life and drinking-water-quality standards. To assess potential effects on human health, solid-phase digestion values for uranium were compared to soil screening levels (SSL) computed using the computer model RESRAD 6.5 for a probable concentration of radium. One or more chemical constituents exceeded aquatic life and drinking-water-quality standards in approximately 64 percent (29/45) of the leachate samples extracted from uranium waste dumps. Most of the uranium waste dump sites with elevated trace-element concentrations in leachates were located in Red Canyon. Approximately 69 percent (31/45) of the strong acid digestible soil concentration values were greater than a calculated SSL. Uranium waste dump sites with elevated leachate and total digestible concentrations may need to be further investigated to determine the most appropriate remediation method.

Nature or petrochemistry?-biologically degradable materials.

PubMed

Mecking, Stefan

2004-02-20

Naturally occurring polymers have been utilized for a long time as materials, however, their application as plastics has been restricted because of their limited thermoplastic processability. Recently, the microbial synthesis of polyesters directly from carbohydrate sources has attracted considerable attention. The industrial-scale production of poly(lactic acid) from lactic acid generated by fermentation now provides a renewable resources-based polyester as a commodity plastic for the first time. The biodegradability of a given material is independent of its origin, and biodegradable plastics can equally well be prepared from fossil fuel feedstocks. A consideration of the overall carbon dioxide emissions and consumption of non-renewable resources over the entire life-cycle of a product is not necessarily favorable for plastics based on renewable resources with current technology-in addition to the feedstocks for the synthesis of the polymer materials, the feedstock for generation of the overall energy required for production and processing is decisive.