Fish, 2,3,7,8-TCDD contamination

Lifetime cancer risk increases from drinking water and eating fish from 2,3,7,8-TCDD-contaminated waters ... 

Fish and Wildlife. A survey of 2,3,7,8-TCDD contamination in benthic (bottom feeding) and predator fish from major U.S. watersheds was conducted for the EPA National Dioxin Study (Kuehl et al. 1989). It was observed that 17 of 90 (19%) samples collected at sites statistically selected by the EPA had detectable levels of 2,3,7,8-TCDD, whereas 95 of 305 (31%) samples from sites chosen by EPA regional laboratories had detectable levels (detection limits 0.5-2 ppt on a wet weight basis). Of the 112 sites where 2,3,7,8-TCDD was detected, 74 samples (67%) were below 5 ppt, 34 samples (32%) were between 5 and 25 ppt, and 4 samples (1%) were above 25 ppt. A subset of samples collected at sites near the discharges from pulp/paper manufacturing facilities (n=28) had a higher frequency of... 

More research is needed on factors that alter bioconcentration, toxicokinetics, and metabolism of PCDDs. For example, field bioconcentration factors (BCF) for 2,3,7,8-TCDD in fish from contaminated rivers in Maine ranged from 3000 to 106,000, and most exceeded the value of 5000 recommended by the U.S. EPA. BCF values between 15,000 and 25,000 are now considered a reasonable estimate of the BCF for use in regulatory purposes in the State of Maine. Mixtures of... 

Johnson, J.E., W.D. Heckathorn, Jr., and A.L. Thompson. 1996. Dispersal and persistence of 2,3,7,8-tetrachlo-rodibenzo-p-dioxin (TCDD) in a contaminated aquatic ecosystem, Bayou Meto, Arkansas. Trans. Amer. Fish. Soc. 125 450-457. 

TCDD concentrations in fish. The TCDD levels measured in fish from lakes and rivers in the United States confirm that 2,3,7,8-TCDD is bioaccumulating in fish and that low-level contamination of... 

Contamination of the Spring River in southwest Missouri by 2,3,7,8-TCDD is believed to have resulted from several well defined point-source waste disposal sites (Crunkilton et al. 1987). Analysis of 31 fish samples (11 different fish species) collected from 1981 to 1983 demonstrated a rapid decline in 2,3,7,8-TCDD concentrations in fish at increasing distances both upstream and downstream from the area of contamination. Mean concentrations of 2,3,7,8-TCDD 0.5 km downstream from the area of contamination were 38 ppt in whole fish and 20 ppt in fish fillets (wet weight basis). Mean concentrations in... 

Wl Health standards for contaminants commonly found in sport fish (2,3,7,8-TCDD) 50 ppt WAC 1988... 

The food chain is the primary pathway of human exposure to dioxin, with meat (38%) and dairy products (28%) dominating. Fish ingestion can be a significant contributor in countries with high fish consumption (26% of total intake in the Netherlands), but is not an important factor in the US. The exact contribution of fruits and vegetables is unclear, but vegetable oil does appear to play a role in human dioxin exposure. Inhalation and consumption of contaminated water and soil are not major sources of human exposure to TCDD. 

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