A Summary of Current Fish Tissue Contaminant Levels on the Mainstem Ohio River

A Summary of Current Fish Tissue Contaminant Levels on the Mainstem Ohio River

Rob A. Tewes, Jeff A. Thomas

Ohio River Valley Water Sanitation Commission (ORSANCO), 5735 Kellogg Ave. Cincinnati, OH, 45230

Abstract

                The Ohio River Valley Water Sanitation Commission (ORSANCO), in conjunction with the United States Food and Drug Administration (FDA) began examining levels of contaminants in fish tissue collected from the main stem of the Ohio River in 1975. Fish tissue contaminant studies were conducted in conjunction with biological monitoring initiatives. Additionally, results of these studies have been used by ORSANCO and the six Ohio River main stem states to determine states’ fish consumption advisories. Samples were obtained from randomly selected sites throughout each of the Ohio River’s 19 pools. Fish tissue samples from the Ohio River were pool-specific composites consisting of right-side fillets from three - five similarly sized individual fish (smallest individual was no less than 75% of total the length of the largest individual in the composite) of a particularly species.  Samples primarily consisted of species that were most commonly encountered, caught by anglers or commercial fisherman, and considered to be most commonly consumed by the public. These taxa included primarily: sauger (Sander canadensis), channel catfish (Ictalurus punctatus), common carp (Cyprinus carpio), hybrid striper (Morone saxatilis X chrysops), freshwater drum (Aplodinotus grunniens) and largemouth bass (Micropterus salmoides). In total ORSANCO has conducted tissue contaminant studies on approximately twenty-eight species.Samples were analyzed for bioaccumulative compounds that were of either known or suspected health risks to humans.  These included PCBs, trace metals (mercury [Hg], cadmium [Cd], selenium [Se], and lead [Pb]), dioxins, pesticides including total chlordanes and total DDTs. More recently polybrominated diphenyl ethers (PBDEs) and perfluorinated compounds (PFCs) have been investigated.  ORSANCO continues to screen for these and other emerging contaminants on a regular basis. Of these compounds, PCBs and Hg remain the primary focus of fish tissue contaminant studies to support fish consumption advisories. Since 1987 ORSANCO investigations have shown a general decline in PCB’s in fish tissue samples. Analyses demonstrated steady declines in DDTs and chlordanes since 1987. Analyses for toxic heavy metals including Hg show more complex relationships with no obvious temporal changes.