PCBs and other toxicants inMysis relicta

Evans, Marlene S.; Bathelt, Ralph W.; Rice, Clifford P.

doi:10.1007/bf00008114

Cited by 31 publications

(1 citation statement)

References 29 publications

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“…Since mirex is one of the most stable compounds ever discharged into Lake Ontario () and because the nearshore bottom sediments redistribute into the water column (), the predicted residence time and availability to biota was believed to be long. Biota associated with the contaminated sediment and important in the food web, such as Mysis and Diporeia , could continue to deliver mirex into the food web for many years, perhaps hundreds of years ( − ). However, results presented here suggest that either this is not happening or it is not a significant problem.…”

Section: Discussionmentioning

confidence: 99%

Trend Analysis Reveals a Recent Reduction in Mirex Concentrations in Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon from Lake Ontario

Makarewicz

Damaske

Lewis

et al. 2003

Environ. Sci. Technol.

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Lake Ontario, bordering both Canada and the United States, is the only Great Lake with persistent, significant levels of mirex in its biota. Some models suggested that it would take hundreds of years before mirex disappeared from the ecosystem. From 1977 to 1996 the mirex concentrations in coho and chinook salmon greater than 2 kg in weight exceeded the 0.1 mg/kg Food and Drug Administration (FDA) action level for mirex. To determine temporal trends in salmonine mirex levels, slopes and elevations of the regression lines of mirex concentration versus fish weight were compared for each of the six sampling years (1977, 1982, 1986, 1992, 1996, and 1999) by ANCOVA with weight as a covariate. Within 24 years of mirex being banned, mirex least-squares mean concentrations in salmon fillets had decreased significantly. ANCOVA revealed that the slope of the 1999 regression line was significantly flatter (P < or = 0.014) than the slopes of all other regression lines except 1996 (P = 0.966). A Tukey test revealed that the elevation of the 1999 regression line was also significantly lower than all other years (P < 0.001). Based on our results, mirex concentrations in the fillets of most salmon under the size of 12 kg are now below the 0.1 mg/kg United States FDA action level for human consumption. Models suggest that mirex reductions in biota are most likely due to the settling of mirex-contaminated organisms to the sediments and the loss of mirex from the lake through the St Lawrence River. A third mechanism is suggested as the cause of the higher rate of reduction observed in the mid to late 1990s--the control and removal of contaminated groundwater at the former Hooker Chemical site on the Niagara River, the major source of mirex in the watershed of Lake Ontario.

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Section: Discussionmentioning

confidence: 99%

Trend Analysis Reveals a Recent Reduction in Mirex Concentrations in Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon from Lake Ontario

Makarewicz

Damaske

Lewis

et al. 2003

Environ. Sci. Technol.

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Accumulation of polychlorinated biphenyl congeners from lake champlain sediments by Mysis relicta

Lester

McIntosh

1994

Enviro Toxic and Chemistry

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Polychlorinated biphenyl (PCB) levels in lake trout (Salvelinus namaycush) from Lake Champlain often exceed the F.D.A. “tolerance level” of 2 μg/g (wet weight). Of added concern are recent studies that suggest a relationship between the dioxin‐like properties of non‐ortho‐substituted PCB congeners and impaired lake trout egg hatchability. Dietary accumulation of PCBs is thought to be an important exposure route for fish. The epibenthic freshwater shrimp Mysis relicta is an integral part of the benthic and pelagic food web in Lake Champlain and may act as a link between PCBs in sediments and lake trout. Previous investigations have shown that diurnal migrations of mysids enhance the movement and distribution of toxic contaminants, effectively coupling the benthic and pelagic zones. The objective of this research was to examine the role contaminated sediments play in the transfer of PCBs to mysids. Bioaccumulation was assessed by exposing mysids to such sediments in two ways: (a) with organisms screened from sediments; and (b) with organisms in direct contact with sediments. Accumulation of PCBs over the course of the 24‐day exposure period was examined on the following days: 0, 3, 6, 12, 21, and 24. Eighty‐nine individual PCB congeners were measured in tissue and sediment. Mysids in direct contact with sediments accumulated significantly higher levels of PCBs than did organisms screened from sediments. Mysids accumulated substantial levels of PCBs, suggesting they may play an important part in the transfer of PCBs from sediments into the Lake Champlain food web. It is clear from this research that sediments can play a critical role in the accumulation of PCBs by mysids.

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Sediment-associated contaminants — an overview of scientific bases for developing remedial options

Förstner

1987

Ecological Effects of in Situ Sediment Contaminants

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PCBs and other toxicants inMysis relicta

Cited by 31 publications

References 29 publications

Trend Analysis Reveals a Recent Reduction in Mirex Concentrations in Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon from Lake Ontario

Trend Analysis Reveals a Recent Reduction in Mirex Concentrations in Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon from Lake Ontario

Accumulation of polychlorinated biphenyl congeners from lake champlain sediments by Mysis relicta

Sediment-associated contaminants — an overview of scientific bases for developing remedial options

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