Interactions of polychlorinated biphenyls (PCBs) {number_sign}126, {number_sign}105 and {number_sign}118 in rainbow trout early life stages
- Univ. of Wisconsin, Madison, WI (United States)
Toxic equivalency factors (TEFs), which relate the toxic potency of polyhalogenated aromatic hydrocarbons (PHAHs) to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are used to predict the risk posed by mixtures of PHAHs. Use of TEFs assumes that PHAH congeners act additively; however, this has not been determined in fish early life stages. PCBs, including potent TCDD-like congener {number_sign}126 and nonactive congeners {number_sign}105 and {number_sign}118, are large contributors to PHAH contamination in feral fish eggs. To determine whether non-active PCBs can interact with more potent congeners, vehicle and 7 graded doses of PCB {number_sign}126 were injected into newly fertilized rainbow trout eggs alone, in combination with PCB {number_sign}105 or {number_sign}118 at ratios that mimicked contamination in Lake Michigan lake trout eggs, and in combination with three ratios of TCDD. TCDD-like toxicity (yolk-sac edema, hemorrhages, craniofacial malformations and mortality) was observed and LD50s (95% fiducial limits) of PCB {number_sign}126 determined using probit analysis for PCB {number_sign}126 alone, {number_sign}126 with {number_sign}105, and {number_sign}126 with {number_sign}118 were 3.84 (2.87--4.61), 4.79 (4.08--5.48) and 4.21 (3.06--4.97) ng/g egg, respectively. Neither the slope of the dose-response curve nor the potency of PCB {number_sign}126 was significantly shifted by PCBs {number_sign}118 or {number_sign}105, indicating that these congeners do not interact at environmental ratios in rainbow trout early life stages. PCB 126 and TCDD were synergistic at a ratio of 400:1 and additive at ratios of 74:1 and 200:1.
- OSTI ID:
- 40040
- Report Number(s):
- CONF-9410273--
- Country of Publication:
- United States
- Language:
- English
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