Gerald T. Ankley

H4IIE rat hepatoma cell bioassay-derived 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in colonial fish-eating waterbird eggs from the Great Lakes

Fish-eating waterbirds from the Great Lakes of North America have shown symptoms of poisoning similar to those observed in laboratory exposures of various avian species to planar halogenated hydrocarbons (PHHs). PHHs, include among others, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) and have been implicated in some of the reproductive problems of Great Lakes waterbirds. The objectives of this study were to assess the overall potencies of PCB-containing extracts from colonial water-bird eggs taken from the Great Lakes and to compare the potencies with the location and spatial distribution of the colonies. The potencies of the extracts were assessed by their ability to induce cytochrome P450IA1-associated ethoxyresorufin O-deethylase (EROD) activity in H4IIE rat hepatoma cells as compared to the standard, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The H4IIE bioassay-derived TCDD-equivalents (TCCD-EQs) in the waterbird eggs concur with residue analyses and biological data from other studies. The greatest concentrations of TCDD-EQs were found in waterbird eggs from historically polluted, industrialized or urbanized areas in which the reproductive impairment of colonial waterbirds was most severe. However, significant concentrations of TCDD-EQs were detected at all sites tested; with a range of 49 to 415 pg TCDD-EQ/g egg, uncorrected for extraction efficiencies. The H4IIE bioassay proved to be a useful biomonitoring tool to assess the overall potency of complex PHH mixtures in environmental samples.

Evaluation of the toxicity of marine sediments and dredge spoils with the Microtox bioassay

The MicrotoxR bioassay was used to evaluate the toxicity of sediment and dredge spoil elutriates from several potentially-contaminated sites in Mobile and Pascagoula Bays. Elutriates were prepared using either local seawater or distilled deionized water (osmotically adjusted with NaCl prior to testing), and MicrotoxR assays were performed with the elutriates and three reference toxicants. There were marked differences in the toxicity of several elutriates and reference toxicants in the two different waters, with the seawater generally resulting in the same or lesser toxicity than the osmotically-adjusted distilled deionized water.

Toxicity of Sediments from Western Lake Erie and the Maumee River at Toledo, Ohio, 1987: Implications for Current Dredged Material Disposal Practices

The toxicity of sediments in the Maumee River, the Maumee River-western Lake Erie federal navigation channel, and selected areas of western Lake Erie was measured using four assays: Photobacterium phosphoreum 15-minute bioluminescence inhibition (Microtox®) in sediment pore-waters and elutriates; Ceriodaphnia dubia 7-day survival and reproduction; Pimephales promelas 7-day larval survival and growth in sediment elutriates; and Chironomus tentans 10-day growth inhibition in whole sediments. The Microtox® assay generally was the most sensitive of the four assays used in this investigation. Sediment elutriates were always equally or more toxic than porewaters from the same location when tested using the Microtox® assay. The greatest toxicity in the Microtox® and C. tentans assays was observed with porewaters or elutriates and sediments collected near point sources of contaminants to the Maumee River. Very little toxicity was observed in any assay using open-lake navigation channel or disposal site sediments or sediment extracts. Previous investigations also have reported little acute toxicity and little or no bioaccumulation of any measured sediment contaminants from study area sediments during laboratory toxicity or bioaccumulation assays. Sediments from the Lake Erie portion of the navigation channel evaluated during this investigation were suitable for open-lake disposal based on the lack of observed effects in the four assays. Toxicity of sediment from the open lake disposal site was similar to that of sediments from other locations in the western basin of Lake Erie which have not been impacted by dredged material disposal events. Sediments from near point sources such as industrial discharges, liquid unloading facilities, or sewage treatment plant outfalls on the Maumee River represent potential sources of toxicity for downstream resuspension and distribution. Further studies will be necessary to delineate the exact distribution of contaminated sediments near the point source discharges to the Maumee River.

Maternal transfer of bioactive polychlorinated aromatic hydrocarbons in spawning chinook salmon (Oncorhynchus tschawytscha)

Abstract The biological potency (relative to 2,3,7,8-tetrachlorodibenzo- p -dioxin. TCDD) of planar polychlorinated aromatic hydrocarbons (PCHs) in extracts of eggs and flesh from spawning female chinook salmon ( Oncorhynchus tschawytscha ) from Lake Michigan was determined by measuring the induction of 7-ethoxyresorufin O -deethylase activity in H-4-II-E rat hepatoma cells. TCDD-equivalents in flesh and egg samples ranged from 0 to 115·8 pg/g, and were approximately 5-fold greater in eggs than in flesh. These results suggest that the maternal transfer of PCHs may play a role in determining the reproductive success of Lake Michigan chinook salmon.

Planar chlorinated hydrocarbons (PCHs) in colonial fish-eating waterbird eggs from the Great Lakes

Abstract Reproductive impairment of double-crested cormorants ( Phalacrocorax auritis ) and Caspian terns Hydroprogne caspia ) has recently been observed in the Great Lakes of North America. Planarchlorinated hydrocarbons (PCHs), which include polychlorinated biphenyls (PCBs), polychlorinated dibenzo- p -dioxins (PCDDS), and polychlorinated dibenzofurans (PCDFs), are believed to be at least partially responsible for the increased incidence of teratogenesis and embryonic mortality. The objective of this study was to assess the potency of the PCH mixtures in egg extracts from these colonial waterbirds. The relative potency of the egg extracts was assessed by their ability to induce cytochrome P-450-dependent ethoxyresorufin O-deethylase (EROD) in H4IIE rat hepatoma cells. The magnitude of the response was compared with EROD induction in cell cultures by a standard, 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD). The TCDD-equivalents derived by this bioassay concur with residue analysis and biological data, in that the highest TCDD-equivalents were found in waterbird egg composites from areas with greater PCH concentrations and more severe reproductive effects. Significant concentrations of PCHs were detected in all sites tested; the range of TCDD-equivalents in the waterbird eggs was 49–415 pg/g, uncorrected for extraction efficiencies. The evidence is strong for at least a partial role of PCHs as causal agents in the reproductive impairment of fish-eating waterbirds from the Great Lakes of North America.

Hepatic enzyme systems as biochemical indicators of the effects of contaminants on reproduction of chinook salmon (Oncorhynchus tschawytscha)

Abstract 1. The reproductive success of 30 female Lake Michigan chinook salmon ( Oncorhynchus tschawytscha ) was evaluated and compared to the status of two hepatic enzyme systems proposed as sensitive biochemical indicators of exposure to planar polychlorinated aromatic hydrocarbons, including certain polychlorinated biphenyls, polychlorinated dibenzofurans and polychlorinated dibenzodioxins. 2. Fertilizability, hatchability and egg and fry mortality varied significantly among the fish. 3. Hepatic monooxygenase and glutathione S-transferase activities and cytochrome P-450E concentration also varied markedly among the fish. 4. There was, however, little correlation between reproductive success and the three biochemical indicators of contaminant exposure.