Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2006
Publication Date: N/A
Interpretive Summary: Alkylphenol and alkylphenol ethoxylates are known endocrine disrupting compounds that commonly occur in polluted waters. Convincing evidence is still meager to show a causality link between the presence of these heavily-used surfactants and endocrine activity in fish. The Environmental Protection Agency of the State of Ohio, organized this study and contracted with us to examine these factors in carp that inhabit the Cuyahoga River. Not just exposure concentrations were monitored, but the actual residue of these surfactants in the fish were obtained in order to compare their concentrations to biomarkers for endocrine disruption in these fish. Of particular emphasis was evidence for the induction of vitellogenin, an egg shell hormone precursor, in male fish and the relative stages of sexual maturity in both sexes of the fish. Analysis of the data revealed that clear dose-response linkages could be seen with increase in vitellogenin in male fish versus concentration of nonylphenol, the most endocrine-active compound in the surfactant mixture. This was particularly noticeable in fish that were collected downstream of the outfall from the Akron waste water treatment plant. Furthermore all fish, both males and females, downstream of this site were more advanced in sexual maturity than those fish collected upstream. The ratio of contaminant in the fish versus the concentration in the water (Bioaccumulation Factors-BAFs) were found to be similar to those observed by other researchers. However, the BAFs for the other more ethoxylated forms (one with 1-ethoxy and the another substituted with 2-ethoxy groups) had higher BAFs than reported by others. No other significant correlations were observed with any of the other endocrine biomarkers that were studied, e.g., gonadosomatic indices, condition factor, and estradiol versus keto-testosterone ratios.
Technical Abstract: Various chemical and biological measures were determined in carp (Cyprinus carpio) sampled from seven sites along the Cuyahoga River, Ohio; from the relatively pristine headwaters to the lower portion heavily polluted from various industrial, urban and wastewater treatment plants (WWTP). Levels of nonylphenol (NP), nonylphenol ethoxylates (NPEs; NP1EO, NP2EO) and total NPEs (NP plus the NPEs) in fish increased in a downstream direction, with maximal values observed below the discharge of the Akron WWTP. In female fish there were no significant differences between sites in GSI or levels of vitellogenin (VTG) and 17'-estradiol (E2). However, differences were observed between sites using measures of 11-ketotestosterone (11-KT) and the ratio E2/11-KT. In male fish the highest levels of VTG were observed downstream of the Akron WWTP and a significant correlation (r=85%) between levels of NP and VTG was demonstrated. No site differences were observed in the measures of GSI, E2, 11-KT or the E2/11-KT ratio in male fish. These data suggest that endocrine active chemicals, such as, NP and NPEs are impacting fish downstream of the Akron WWTP; however, further work is warranted to separate linkages to other possible chemical factors in the water.