Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

Abstract

Organochlorine chemical residues and elemental concentrations were measured in piscivorous and benthivorous fish at 111 sites from large U.S. river basins. Potential contaminant sources such as urban and agricultural runoff, industrial discharges, mine drainage, and irrigation varied among the sampling sites. Our objectives were to provide summary statistics for chemical contaminants and to determine if contaminant concentrations in the fish were a risk to wildlife that forage at these sites. Concentrations of dieldrin, total DDT, total PCBs, toxaphene, TCDD-EQ, cadmium, chromium, mercury, lead, selenium, and zinc exceeded toxicity thresholds to protect fish and piscivorous wildlife in samples from at least one site; most exceedences were for total PCBs, mercury, and zinc. Chemical concentrations in fish from the Mississippi River Basin exceeded the greatest number of toxicity thresholds. Screening level wildlife risk analysis models were developed for bald eagle and mink using no adverse effect levels (NOAELs), which were derived from adult dietary exposure or tissue concentration studies and based primarily on reproductive endpoints. No effect hazard concentrations (NEHC) were calculated by comparing the NOAEL to the food ingestion rate (dietary-based NOAEL) or biomagnification factor (tissue-based NOAEL) of each receptor. Piscivorous wildlife may be at risk from a contaminant if the measured concentration in fish exceeds the NEHC. Concentrations of most organochlorine residues and elemental contaminants represented no to low risk to bald eagle and mink at most sites. The risk associated with pentachloroanisole, aldrin, Dacthal, methoxychlor, mirex, and toxaphene was unknown because NOAELs for these contaminants were not available for bald eagle or mink. Risk differed among modeled species and sites. Our screening level analysis indicates that the greatest risk to piscivorous wildlife was from total DDT, total PCBs, TCDD-EQ, mercury, and selenium. Bald eagles were at greater risk to total DDT and total PCBs than mink, whereas risks of TCDD-EQ, mercury, and selenium were greater to mink than bald eagle.

Currently used pesticides, hexachlorobenzene and hexachlorocyclohexanes in the air and seawater of the German Bight (North Sea)

“…The term 'currently used pesticide' used here means pesticides which are not subject to worldwide restrictions. These CUPs attract our interest because of their continued high production volume and occurrence in aquatic biota, [10][11][12] osprey eggs, [13] human breast milk [14] and Arctic media (e.g. air, water and ice).…”

Contamination of Fish and Sediments from the Vistula River by Organochlorine Pesticides and PCBs

“…The bioaccumulation of contaminants such as DDTs (mainly as DDE), PCBs, dioxins, and heavy metals by fish represents a potentially significant risk to piscivorous wildlife [11,12,17]. Fish often comprise a substantial dietary portion of mammalian and avian species, and therefore represent a significant route of contaminant exposure.…”

“…For wildlife protection assessments, whole fish analyses are optimal. Because the susceptibility to contaminants varies among species, tissue residue guideline (toxicity threshold) for the protection of wildlife consumers of aquatic biota for DDTs was calculated as 0.15-3.0 µg/g and for PCBs 0.11-0.48 µg/g [17]. Although the concentrations of many persistent organochlorine chemical residues have declined over the past two decades, our and others authors' results indicate that contaminant residues still remain a risk to piscivorous wildlife at some sites [4,12,17,18].…”

Levels of arsenic, mercury and selenium inClarias gariepinusfrom Sagua la Grande River, Cuba

“…These concentrations are lower in all cases than the recommended maximum concentration limit by the Cuban standard of 1 mg.g x1 ww of As for fish consumption (NC-493, 2006) and in the same order of magnitude reported by other authors in freshwater fish. Hinck et al (2009) reported average concentration of 0.11 mg.g x1 ww for As in fish collected at 111 sites from some important river basins from the USA, with a maximum of 1.95 mg.g x1 ww for whole body. During a survey on fish fillets from Oak Ridge Reservation in Tennessee, USA, Burger and Campbell (2004) detected the presence of As in a concentration range between 0.085 and 0.140 mg.g x1 .…”

“…For instance, in the Savannah River, USA, were found average levels of Se in fillet between 0.21 and 0.64 mg.g x1 ww for various species (Burger et al, 2001). Hinck et al (2009) studied piscivorous and benthivorous fish at 111 sites from US river basins and reported a mean of 0.59 mg.g x1 ww of Se in whole fish with a maximum value of 4.66 mg.g x1 ww. Lemly (1993) proposed an Se reference concentration of 4 mg.g x1 dw in whole body as threshold values for selenium toxicity involving reproductive failures and teratogenic deformities in young fish, although adults can survive and appear healthy.…”