1,864 research outputs found
Tracing Kepone contamination in James estuary sediments
The escape of Kepone into the James River estuary, Virginia, for more than nine years produced widespread contamination of the sediments with important ecological consequences. The pollutant extended seaward more than 100 km from its source and contaminated an estimated 31 million tonnes of sediment to depths of more than 60 cm. Kepone spread through the food chain and to every segment of the environment from marshes to the channel floor.
Kepone escaped mainly during high river inflow from a point source in freshwater tributaries. Near the source Kepone is associated with organic material but in the low er estuary it is adsorbed on finegrained sediment. A bulk of the contaminated sediment is transported and trapped by the estuarine circulation. It accumulates in the turbidity maximum of the middle estuary far from the source. In this zone it is deposited in less energetic sites where sedimentation is relatively fast. Contamination extends downward \u3e 60 cm ; peak concentrations at 10 to 25 cm relate to high production in 1974. The Kepone inventory is now being buried by less contaminated sediment. “ Recovery” is most rapid in the middle estuary where contamination was most intense
Kepone in the James River Estuary: Past, Current and Future Trends
In late 1975, a manufacturing facility in Hopewell, VA had not only exposed workers to the chlorinated pesticide, Kepone, but had also severely contaminated the James River estuary. To assess the potential risk to the public, Virginia initiated a finfish-monitoring program in late 1975. Over the next 40 years over 13,000 samples were collected from the James River and Chesapeake Bay and analyzed for Kepone. Kepone production was eventually banned worldwide. The average Kepone concentrations found in most species began falling when the production of Kepone ended, but the averages remained over the action limit of 0.3 mgkg-1 until the early 1980s. By 1988, few fish contained average Kepone concentrations greater than the action limit. Kepone was still detected (\u3e0.01 mgkg-1 wet weight) in the majority of white perch and striped bass samples taken from the James River in 2009 and a fish consumption advisory is still in effect over forty years after the source of contamination was removed.
Due to state budget cuts, monitoring of Kepone has not been conducted since 2009. As part of its 40th Anniversary, the Virginia Environmental Endowment -- which was established as part of the Kepone pollution court settlement in 1977 -- requested that VIMS conduct an updated study of the current levels of Kepone in the James River
Effects of food ration size on bioaccumulation of kepone by spot (Leiostomus xanthurus) and grass shrimp (Palaemonetes pugio) (pharmacokinetics, dietary accumulation, accelerated test, bioconcentration, assimilation efficiency)
Long-term bioaccumulation studies were conducted using (\u2714)C-Kepone and unlabeled Kepone to determine the significance of dietary accumulation to final Kepone body burdens in spot (Leiostomus xanthurus) and grass shrimp (Palaemonetes pugio). Both food (grass shrimp) and consumer organisms were exposed to aqueous Kepone concentrations of 0.04 (mu)g/l at 23�C for 16-19 days, followed by a 21-28 day clearance phase. Dietary and aqueous sources of Kepone were shown to be additive for both species. Dietary contributions of Kepone represented 9, 18 and 38% of the total Kepone body burden in spot fed contaminated food rations of 4, 8 and 20% mean body weight, respectively. at rations of 4 and 8%, dietary Kepone contributions to final shrimp body burdens were 24 and 33%, respectively. There were no significant differences in organism size or lipid content among treatments for either species. Ration size had no effect in either organism on the uptake and clearance rate constants estimated for dietary accumulation and bioconcentration by a first-order pharmacokinetic model. Shrimp had a slower clearance rate of Kepone than spot and, hence, a greater bioaccumulation potential. Kepone derived from aqueous exposures to both species appeared to be cleared more slowly than residues derived from dietary exposure. Kepone assimilation efficiencies for spot and shrimp were 15% and 21%, respectively, for the finely ground food source used in this study. These values are low compared to literature data for other lipophilic chlorinated hydrocarbons. This indicates that grinding of the food reduced Kepone availability to the consumer organisms. Event at these low assimilation efficiencies, Kepone from the diet contributed significantly to final Kepone body burdens in spot and shrimp. An accelerated test methodology was adequate to describe spot bioaccumulation kinetics, especially at the larger food ration size tested. Uptake of Kepone from contaminated artificial food was similar to uptake from contaminated natural food
The Effects On The Reproductive Organs Of Mice Following In Utero Exposure To Kepone
Twelve pregnant Swiss-Webster mice were injected, intraperitoneally with Kepone on days 7-16 of gestation. Four mice received 0.1 ml of 2.5 mg of Kepone dissolved in 1.0 ml of sesame oil; four mice received 0.1 ml of 5.0 mg of Kepone dissolved in 1.0 ml of sesame oil; and the last four mice received only 0.1 ml of sesame oil. Litter size was reduced for those injected with Kepone. The male test progeny had a more rapid initial testicular development than the controls, but this slowed until at maturation, testicular development and histology were the same as the controls. The female test progeny had decreased corpus luteum formation, and a greater number and size of developing follicles than the controls; although both female test groups showed these abnormalities, only those receiving 5.0 mg of Kepone were significantly affected
Estimate of the total weight of Kepone in the major components of the molluscan fauna of the James River, Virginia
Contamination of the James River in Virgin ia with the pesticide Kepone has resulted in its accumulation in the tissues of the fauna inhabiting the river. Most of the Kepone available to the biota in the river is associated with sediment s (Schneider and Dawson, 1978) and Haven and Morales-Alamo (1979) have shown that oysters and other bivalve molluscs accumulate Kepone in their tissues when exposed to the pesticide associated with sediments in suspension. It is of interest to compare the quantities of Kepone bound in James River sediments with the quantities bound in the molluscan fauna of the river
Kepone Toxicity to Estuarine Microorganisms
Synthesized chemical agents can have an unseen, and yet profound, impact on the environment in which it is used. This study investigates the effects of the insecticide Kepone (99% pure) on estuarine microbial populations and seeks to determine the mode of toxicity to pure culture isolates obtained therein. The researcher used disc agar diffusion sensitivity, plate counts, and oxygen uptake methods to collect data over a period of four months to determine the toxicity of Kepone to a variety of laboratory pure cultures of bacteria and fungi. Of the 30 isolates tested, 33% were inhibited at 3.65 μg/disc concentration and 47% were inhibited at the 14.6 μg/disc concentration. Higher concentrations (20 μg/disc) inhibited all isolates. Of the 30 isolates, seven were particularly sensitive to Kepone, with four indicating inhibition at the 1.46 μg/disc concentration. The researcher then examined the toxicity of Kepone to natural mixed populations of bacteria from a variety of marine habitats by performing standard total viable counts using Zobell’s seawater agar (Z-15) containing dissolved Kepone. The researcher observed that Kepone as low as 20 μg/l has an inhibitory effect on the development of colonies on an agar plate, though the populations’ sensitivities were variable. In many cases, it was clear that concentrations below 20 μg/l were inhibitory. Seventeen Kepone-resistant colony forming units were selected for further study, however, examination of cell type and enzymatic activities showed significant correlation only with the amylolytic and lipolytic activities, and the gram stain. The researcher observed that organisms grown under anaerobic conditions exhibited decreased sensitivity to Kepone, however, significant reductions in colony forming units were observed under aerobic conditions. The researcher concludes that Kepone is toxic to microorganisms even in low concentrations
Kepone monitoring at Skiffs Creek : in fulfillment of contract number DACW65-79-C-0027
Kepone entered the James River estuary from point sources of production and through runoff from unauthorized disposal sites in the vicinity of Hopewell, Virginia. The total quantity of Kepone released to the river is not known, however, about 1.5 x 106 kg were produced between 1966 and 1975. At present we estimate that 30,000 kg reside in contaminated sediments of the estuary.
Bed sediments are contaminated from the source at Hopewell to Hampton Roads, a distance of 88 kilometers. Patterns of contamination vary with sediment type and distance from the source. Major Kepone sinks exist in the Jamestown - Dancing Point reach and in Burwell Bay. Sediments from these zones are generally finer-grained and more enriched in organic matter than elsewhere and these zones are sites of relatively high sediment accumulation and fast deposition. This extensive contamination of the river sediments by Kepone presents problems for managers having to make decisions on dredging actions in the river. The most important questions which need to be answered concerning dredging activities are:
1) Will dredging result in significant quantities of Kepone being released to the environment?
2) Will the releases spread the contamination or result in increased bioaccumulation of Kepone in organisms?
3) Will the spoil disposal methods release Kepone to the marine environment or ground water? (...
Depuration Of Kepone By Atlantic Croaker In A Laboratory Study
Contamination of the James River in Virginia by the organochlorine pesticide Kepone R prompted depuration studies of commercially important species. Approximately 400 croaker (Micropogonias undulatus) were taken from the James River and placed in Kepone-free York River water. Groups of 20 fish, maintained at ambient temperature, were sampled over time to determine depuration rate. Results suggest that there is no substantial depuration of Kepone by croaker until water temperature exceeds 15 C.https://scholarworks.wm.edu/vimsbooks/1109/thumbnail.jp
Uptake of Kepone by oysters exposed to contaminated sediments mixed with lignite
Preliminary studies conducted by personnel of the Allied Chemical Corporation at Morristown, N. J. suggested that coa] would be used to adsorb Kepone from an aquatic substrate. .The possibility of using coal to bind Kepone contaminating the natural environment indicated further preliminary exploration of the matter.
The Virginia Institute of Marine Science undertook a laboratory study with oysters under contract with the Allied Chemical Corp. to explore that possibility. Lignite was mixd on a 1:10 dry-weight ratio with sediments contaminated with Kepone
The Effects of Kepone on the Estuarine Copepod \u3ci\u3eAcartia tonsa\u3c/i\u3e
Due to the contamination of a 113 km reach of the James River, Kepone poses a serious environmental threat to the Chesapeake Bay. The purpose of the study is to determine the acutely toxic and sublethal levels of kepone for the copepod Acartia tonsa, and to investigate what effects those levels may have on filtration rates.
Kepone was determined to be acutely toxic to A. tonsa, with a 96 hour LC50 of 4.96 ug/1. Dunaliella tertiolecta was selected as the food source for the grazing experiments. Kepone concentrations of 0.046 ug/1 significantly (0.05 level) reduced the flltering rate under conditions of chronic exposure. The lesser concentrations of 0.025 and 0.0046 ug/1 of kepone were not significantly different from the controls. It is hoped that research into the chronic stress of this pesticide may potentially provide information which would be useful in the overall understanding of the sublethal impact of chlorinated pesticides on a global scale
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