Reproductive toxicity in mink (Mustela vison) chronically exposed to environmentally relevant polychlorinated biphenyl concentrations

Abstract

Female mink were exposed to a technical polychlorinated biphenyl (PCB) preparation (Clophen A50 [A50]; 0.1 or 0.3 mg/animal/d), one fraction of A50 containing the non- and mono-ortho-chlorinated congeners (0-1-ortho-chlorobiphenyls [CBs]), another fraction of A50 containing the congeners with two to four ortho-chlorines (2-4-ortho-CBs), or an organic extract from Baltic gray seal blubber. The animals were exposed for 18 months, including two reproduction seasons. Among the animals given the highest dose of A50, the whelping frequency was reduced in the second reproductive season, and all kits died within 24 h of birth. Reproduction was also impaired by the lower dose of A50. Daily exposure to the 0-1-ortho-CBs separated from 0.3 mg A50 severely reduced kit survival. Reproduction was not significantly impaired by daily exposure to the 2-4-ortho-CBs separated from 0.3 mg A50 or by exposure to the blubber extract. We conclude that the reproductive toxicity in chronically PCB-exposed mink is caused by the aryl hydrocarbon (Ah) receptor agonists. The lowest-observed-effect level for reproductive impairment was 2.4 ng 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQs) per kilogram body weight and day (22 pg TEQs/g feed). Ethoxyresorufin-O-dealkylase (EROD) was strongly induced by the 0-1-ortho-CBs and pentoxyresorufin-O-dealkylase by the 2-4-ortho-CBs. High EROD activity was correlated with low kit production, and consequently EROD may serve as a marker for reproductive toxicity by Ah receptor agonists in mink.

Xenobiotics and the Glucocorticoid Receptor: Additive Antagonistic Effects on Tyrosine Aminotransferase Activity in Rat Hepatoma Cells

“…Wildlife and humans are constantly exposed to environmental chemicals and there have been several studies on effects of simultaneous exposure to persistent environmental pollutants (Brunström et al 2001; Chu et al 2001). In this study we used multivariate modelling to analyse the effects on tyrosine aminotransferase activity by co‐exposing cells to different combinations of the test substances.…”

Exposure and effects assessment of resident mink (Mustela vison) exposed to polychlorinated dibenzofurans and other dioxin‐like compounds in the Tittabawassee River basin, Midland, Michigan, USA

“…5): The TRVs used in the present study were derived from a rigorous assessment of the available literature regarding the effects of dioxin‐like compounds on mink [17]. All the studies used in deriving the TRVs were conducted on mink [4,20–22]. The studies available in the literature were evaluated based on criteria such as duration, sensitivity, and ecological relevance of the endpoints as well as similarity of the constituents in the study relative to those comprising the TEQs observed in mink from the TR.…”

Growth and reproductive effects from dietary exposure to Aroclor 1268 in mink (Neovison vison), a surrogate model for marine mammals

“…Conversely, the continuous exposure of Aroclor 1268-treated mink was akin to an unlikely exposure scenario where Turtle-Brunswick River estuary dolphins forage exclusively within the contaminated estuary. Regardless of physiological and life history differences between mink and dolphins, the magnitude of PCB concentrations in mink tissues associated with reproductive failure was remarkably high relative to threshold concentrations available for most Aroclors and environmental mixtures [16,52,53,[74][75][76][77] and compared with PCB concentrations in Turtle-Brunswick River estuary bottlenose dolphins [18]. This is evidence that the potential for reproductive impairment induced by exposure to Aroclor 1268 may be low in Turtle-Brunswick River estuary dolphins based on reported exposures, although reproductive effects in the F1 generation or beyond were not tested.…”