Organochlorine insecticides, polychlorinated biphenyls, and metals in water, sediment, and green frogs from southwestern Michigan.

In an attempt to explain the etiology of frog deformities and population declines, many possible causative factors have been examined, including the input of synthetic chemicals into aquatic systems, where frogs spend much of their lives, including their entire developmental stages. Deformities in populations of green frogs in wetlands of southwestern Michigan that are influenced by agricultural, urban, or industrial inputs were assessed in this study. Of the 1445 green frogs (Rana clamitans) examined, only four (0.3%) exhibited morphological deformities. This deformity rate is less than the recognized background level of deformities for this species, which is approximately 1%. Concentrations of organochlorine insecticides, polychlorinated biphenyls (PCBs), and metals were determined in water, sediment, frog eggs, tadpoles, and adult green frog tissues. Concentrations of all individual organochlorine insecticides in tissue were less than 6 ng/g, wet wt. Concentrations of sigmaPCBs in tissue did not exceed 100 ng/g, wet wt. Concentrations of toxic metals were less than the limits of detection. Because no significant numbers of green frog deformities were observed in this region, it can be assumed that at these low concentrations, physical malformations in green frogs should not be observed. Significance of study. This study provides information on the incidence of deformities in green frog populations in southwestern Michigan and offers background data on chemical residues in green frogs and their environment.

SCRAM: A scoring and ranking system for persistent, bioaccumulative, and toxic substances for the North American Great Lakes. Part IV: Results from representative chemicals, sensitivity analysis, and discriminatory power.

The Chemical Scoring and Ranking Assessment Model (SCRAM) has been described in Parts I-III of this series (Snyder et al.: , 1999a; 1999b; 1999c). SCRAM is a chemical scoring and ranking (CSR) system that scores chemicals on the basis of bioaccumulation potential, environmental persistence, and toxicity. Part IV describes various tests and descriptions of the performance of this system. A group of 21 representative chemicals was chosen and scored to test the system. For those chemicals, the percentages of the scores associated with fate-related properties and associated with data uncertainty were determined. The scoring of four of these chemicals is described in greater detail, and the suitability of the scores is discussed. An analysis of the sensitivity of the system to incomplete data sets is presented. And finally, the discriminatory power of the system is described.

SCRAM: A scoring and ranking system for persistent, bioaccumulative, and toxic substances for the North American Great Lakes. Part II: Bioaccumulation potential and persistence.

Part I (Snyder et al.: , 1999a) of this series introduced SCRAM, a chemical scoring and ranking system for contaminants of the North American Great Lakes. Here, in Part II, scoring of the bioaccumulation potential and persistence of chemicals is discussed, including acceptable types of data, specific scoring instructions, and the basis for criteria and scores for these categories of the system. Difficulties encountered during the process of determining which types of data adequately represent the properties of interest are discussed. Also, justification is given for an emphasis on scoring on the basis of persistence.

SCRAM: A scoring and ranking system for persistent, bioaccumulative, and toxic substances for the North American Great Lakes. Part III: Acute and subchronic or chronic toxicity.

In Part I of this series (Snyder: et al., 1999a), the Chemical Scoring and Ranking Assessment Model (SCRAM) was introduced. This system produces scores for chemicals based on their bioaccumulation potential, environmental persistence, and toxicity. In Part II, scoring of the potential for a chemical to persist in the environment and bioaccumulate was described (Snyder et al., 1999b). In Part III, scoring of chemical toxicity is discussed, including definitions and descriptions of effects that are scored, specific scoring instructions, the basis for the criteria and scores, and specific conditions or concerns regarding the types of data used for scoring. A score for each chemical screened is determined from available test data from acute or subchronic and chronic toxicity tests conducted on aquatic and terrestrial organisms. Subchronic and chronic human health effects, including carcinogenicity, are also considered. Part IV includes an evaluation of the performance of the scoring and ranking system (Snyder: et al., 1999c).

SCRAM: A scoring and ranking system for persistent, bioaccumulative, and toxic substances for the North American Great Lakes. Part I: Structure of the scoring and ranking system.

Hundreds of chemical contaminants have been identified in the Great Lakes System of North America. Depending on the agency or organization, various subset lists of these contaminants have been identified as chemicals of potential concern. However, there is no agreement on the method that should be used to make management decisions. Except for consensus on approximately 40 chemicals that most North American agencies agree can cause deleterious effects if released into the environment, no agreement has been reached regarding the priority that contaminants should receive for further action. That leaves hundreds of chemicals that have been, are being, or potentially could be released into the environment that have not been evaluated yet. A profile for potential chemicals of concern is generally thought to include persistence in the environment, potential to bioaccumulate, and ability to cause toxic effects at environmentally relevant concentrations. Except for the International Joint Commission's definition of persistence (> 8 weeks residence time in air, water, soil or sediment), there is little concurrence about what defines these characteristics. For instance, the State of Michigan currently has no established definitions or profiles of persistent, bioaccumulative, toxic substances. Furthermore, there is no standard process to rank chemicals relative to these characteristics. The Chemical Scoring and Ranking Assessment Model (SCRAM) has been developed to provide a process to rank-order chemicals based on these characteristics. The SCRAM system was developed primarily for use in the Great Lakes region of North America and particularly in Michigan, but it is not site-specific. Use of this system may assist in pollution prevention activities and other future chemical control efforts, allowing attention to be focused first on those chemicals likely to present the greatest hazard.

Effects induced by feeding organochlorine-contaminated carp from Saginaw Bay, Lake Huron, to laying White Leghorn hens. I. Effects on health of adult hens, egg production, and fertility.

This study was conducted to determine the effects of consumption of halogenated hydrocarbon compounds, primarily polychlorinated biphenyls (PCBs), contained in Great Lakes fish by the domestic chicken (Gallus domesticus). In this article we report the results of feeding White Leghorn hens for a period of 8 wk diets that contained 31-35% ocean fish and/or carp (Cyprinus carpio) from Saginaw Bay, Lake Huron, MI, which provided 0.3 (control), 0.8 (low-dose group), or 6.6 (high-dose group) mg PCB/kg, wet weight (ww). These concentrations were analogous to 3.3, 26, or 59 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQs)/g diet, ww, respectively. There were no significant effects on feed consumption among the groups. An unexpectedly high incidence of fatty liver hemorrhagic syndrome (FLHS) was observed in hens from the control (78% FLHS) and low-dose (75% FLHS) groups when compared to the high-dose group (15% FLHS). Birds in the control and low-dose groups had a significant increase in liver and body weights. Significant decreases in egg production, weight, and fertility were immediate in all dose groups, with the effect being permanent in the control and low-dose groups. Although the incidence of FLHS was an unexpected complication, the fact that there were no significant effects on egg production, egg weights, or fertility in the high-dose group suggests that the no-observable-adverse-effect concentration (NOAEC) for these parameters is in excess of 26 mg total weathered PCBs/kg egg, ww. This value was the average concentration of PCBs in the high-dose group eggs during the last week of the study.

Effects induced by feeding organochlorine-contaminated carp from Saginaw Bay, Lake Huron, to laying White Leghorn hens. II. Embryotoxic and teratogenic effects.

Carp from Saginaw Bay, Lake Huron, MI, was fed to White Leghorn chickens for a period of 8 wk. The diets contained 0.3 (control; 0% carp), 0.8 (3.4% carp), and 6.6 (35% carp) mg polychlorinated biphenyls (PCBs)/kg diet, by wet weight (ww). These concentrations corresponded to 3.3, 26, and 59 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents/g diet ww, respectively. Though the diets were not acutely toxic to the adult laying hens, dose- and time-dependent responses were observed in the embryos and chicks. Toxicity was manifested as a dose-dependent increase in embryo mortality and decreased hatching rates. Furthermore, embryos and chicks displayed various deformities, including (1) head and neck edema and hemorrhage, (2) abdominal edema and hemorrhage, (3) foot and leg deformities, (4) skull and brain deformities, (5) yolk-sac deformities, and (6) miscellaneous deformities. The types of deformities observed were similar to those reported for embryos and chicks of colonial waterbirds in Saginaw Bay, as well as in controlled studies where technical mixtures or individual congeners of polychlorinated diaromatic hydrocarbons (PCDAHs) were fed to chickens. Increasing concentrations of carp also significantly affected the various organ weights in 18-d embryos and hatched chicks. At 18 d of incubation, weights of the embryos' livers were directly proportional to the concentration of PCBs in the diets. The weights of the spleens and bursae were inversely proportional to the dietary PCB concentration. After 3 additional days of incubation, significant effects in body, brain, liver, heart, and bursa weights were observed in hatched chicks. The concentrations of total PCBs, as well as 2,3,7,8-TCDD equivalents (TEQs) in the diets, were in the range of those that have been shown to cause similar adverse effects in other species. This study has shown that fish, the primary food source of colonial waterbirds in Saginaw Bay, are capable of causing adverse reproductive effects in a model avian species, the chicken. However, due to differences in the relative potency to cause effects on different endpoints in different species, the results of this study should not be used to predict the threshold for effects in other species.

Contaminants of fishes from Great Lakes-influenced sections and above dams of three Michigan rivers: III. Implications for health of bald eagles.

Recently, there have been discussions of the relative merits of passage of fishes around hydroelectric dams on three rivers (Au Sable, Manistee, and Muskegon) in Michigan. A hazard assessment was conducted to determine the potential for adverse effects on bald eagles that could consume such fishes from above and below dams on the three primary rivers. The hazard assessments were verified by comparing the reproductive productivities of eagles nesting in areas where they ate primarily fish from either above or below dams on the three primary rivers, as well as on two additional rivers in Michigan, the Menominee and Thunder Bay. Concentrations of organochlorine insecticides (OCI), polychlorinated biphenyls (total PCBs), 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ), and total mercury (Hg) were measured in composite samples of fishes from above and below hydroelectric dams on the Manistee and Muskegon Rivers, which flow into Lake Michigan, and the Au Sable River, which flows into Lake Huron. Mean concentrations of OCI, total PCBs, and TCDD-EQ were all greater in fishes from below the dams than in those from above. The hazard assessment indicated that current concentrations of Hg and OCI other than DDT (DDT+DDE+DDD) in fish from neither above nor below dams would present a significant hazard to bald eagles (Haliaeetus leucocephalus). Both total PCBs and TCDD-EQ in fishes from below the dams currently present a significant hazard to bald eagles, since their mean hazard quotients (HQ) were all greater than one.