An integrated biomarker approach for assessing exposure and effects of endocrine disruptors and other contaminants in killifish (Fundulus heteroclitus) from the New York-New Jersey harbor estuary:

A multi-tiered approach was used to evaluate killifish (Fundulus heteroclitus) health by examining a suite of biomarkers in killifish inhabiting the heavily industrialized Newark Bay and a reference population in Tuckerton, NJ. The general hypothesis of this study was that Newark Bay killifish would exhibit biomarker responses indicative of impaired health when compared to a reference population from Tuckerton, NJ. The biomarkers investigated included classical endpoints (histopathology, morphometrics, gonad maturation), hepatic mRNA expression (CYP1A, metallothionein, vitellogenin I), gonadal aromatase mRNA expression, hepatic protein levels (CYP1A and vitellogenin I) and chemical exposure analyses (bile PAHs). Newark Bay fish had significantly higher levels of bile PAHs compared to reference fish. Females had significantly higher concentrations of naphthalene, pyrene and benzo[a]pyrene (3, 6 and 4 fold higher, respectively, p<0.05). Males had significantly higher concentrations of pyrene (7-fold higher, p<0.05), and higher concentrations of naphthalene (4-fold higher, p=0.06) and benzo[a]pyrene (9-fold higher, p=0.07). Histological lesions of the liver and pancreas in Newark Bay fish were similar to reference fish. Newark Bay fish had significantly higher expression of hepatic CYP1A for both males and females (7 and 3 fold higher, respectively, p<0.05) and CYP1A protein levels for both males and females (5 and 8 fold higher, p<0.05). Endocrine disruption in male gonads is demonstrated by a decreased gonad weight, altered testis development and upregulated aromatase expression (3-fold, p<0.05), which indicates exposure to endocrine active compounds. Efforts to strip spawn Newark Bay females produced few viable eggs, while at the same time Tuckerton females produced large numbers of viable eggs. There was a significant increase in the percent of pre-vitellogenic follicles (43% at Tuckerton, 64% at Newark Bay) and a significantly decreased percent of follicles at the mid-vitellogenic and mature stages (25% at Tuckerton, 3% at Newark Bay) in Newark Bay females (p<0.05). Vitellogenin mRNA and protein (egg yolk-protein) was significantly decreased in Newark Bay females (6-fold lower mRNA, 27-fold lower protein, p<0.05) while gonadal aromatase (produces 17β-estradiol) was significantly increased (210-fold higher, p<0.05). Killifish in the NY-NJ Harbor Estuary are exposed to high amounts of PAHs and aryl hydrocarbon agonists and their reproductive health is impaired. Impaired reproductive health is possibly due to disruption of steroid signaling by aryl hydrocarbon receptor-estrogen receptor crosstalk leading to decreased vitellogenin production.M.S.Includes bibliographical references (p. 91-100)by Sean M. Buge