Multiple bioindicators of environmental pollution in a sentinel species, Chrysemys picta, on Cape Cod, MA

Abstract

High-level environmental contamination has been documented as eliciting negative effects on endocrine, reproductive and developmental events across vertebrate groups in the wild. Of particular interest and importance is whether relatively low levels of mixtures of environmental pollutants may have long-term impacts. We are investigating responses to ground and surface-water pollution from plumes on the MMR Superfund site on Cape Cod, MA, in the turtle Chrysemys picta. Parameters examined included hepatic cytochrome P450 1A (CYP1A) activity and protein, glutathione-S-transferase (GST) activity, plasma vitellogenin levels, and metallothionein protein. Hepatic microsomal EROD activity in both males and females was higher at the plume-impacted site than at the non-impacted site; a seasonal pattern of activity was seen at both sites. The level of CYP1A protein expression was greater at the impacted site. GST activity also followed a seasonal pattern, but there were no significant differences in activity between the two sites. Plasma vitellogenin levels, although influenced by endogenous estrogen, were significantly lower in animals from plume impacted than non-impacted sites. Serum vitellogenin levels were very low to non-detectable in males. Metallothionein levels show a sex-specific difference at the non-impacted site only; there were no significant differences between the sites. Taken together, the observed changes suggest a potential ground water pollution impact on the endemic biota. These changes are of concern since they suggest that chronic exposure to low level mixtures of contaminants may represent long-term impacts. [Supported by ES07381 to I.P.C. and J.J.S.]