Erin M. Snyder

Bioconcentration of nonylphenol in fathead minnows (Pimephales promelas)

Bioconcentration of p-nonylphenol (NP) by fathead minnows was determined under laboratory conditions. Fish were exposed continuously for 42 days to 0.33, 0.93 and 2.36 microg NP/l in a flow-through system. NP was Soxhlet extracted from whole fish homogenates with dichloromethane (DCM). The resulting extract was concentrated and bulk lipids removed by gel permeation and silica-gel chromatography. Compounds were identified and quantified by reverse-phase high-pressure liquid chromatography (RP-HPLC) with fluorescence detection. Mass spectrometry was used for verification of peak assignments. Bioconcentration factors (BCFs) ranged from 245 to 380.

SCRAM: A scoring and ranking system for persistent, bioaccumulative, and toxic substances for the north american great lakes

The Scoring and Ranking Assessment Model (SCRAM) was developed to serve as an analytical tool in chemical scoring and ranking of Great Lakes contaminants. The model provides an initial screening evaluation, based on minimal amount of data, of large numbers of chemicals to identify those chemicals that have the greatest potential to cause adverse effects. The SCRAM model is different from most screening systems in that it assesses uncertainty. The SCRAM model was used to score a list of contaminants existing or potentially present in the Great Lakes. Data on environmental fate properties, such as persistence and bioaccumulation potential and toxicity were compiled on selected chemicals. Uncertainty scores were also assigned based on incompleteness of the database. A score was calculated for each chemical and given a relative rank based on its persistence, bioaccumulation, toxicity, and uncertainty. The relative rankings of chemicals can be used as a decision-making tool to determine which chemicals need immediate research or monitoring based on their SCRAM score and the chemical’s use and environmental loading.

SCRAM: A Scoring and Ranking System for Persistent, Bioaccumulative, and Toxic Substances for the North American Great Lakes-Resulting Chemical Scores and Rankings

The Scoring and Ranking Assessment Model (SCRAM) was developed to serve as an analytical tool in chemical scoring and ranking of Great Lakes contaminants. The model provides an initial screening evaluation, based on minimal amount of data, of large numbers of chemicals to identify those chemicals that have the greatest potential to cause adverse effects. The SCRAM model is different from most screening systems in that it assesses uncertainty. The SCRAM model was used to score a list of contaminants existing or potentially present in the Great Lakes. Data on environmental fate properties, such as persistence and bioaccumulation potential and toxicity were compiled on selected chemicals. Uncertainty scores were also assigned based on incompleteness of the database. A score was calculated for each chemical and given a relative rank based on its persistence, bioaccumulation, toxicity, and uncertainty. The relative rankings of chemicals can be used as a decision-making tool to determine which chemicals need immediate research or monitoring based on their SCRAM score and the chemicals use and environmental loading.

Effects of waterborne exposure to 4-nonylphenol on plasma sex steroid and vitellogenin concentrations in sexually mature male carp (Cyprinus carpio).

4-Nonylphenol (NP) has been shown to elicit estrogenic responses both in vivo and in vitro. The mechanism by which NP exerts estrogenic and other endocrine-modulating effects in vivo remains unclear, however. The goal of this study was to evaluate the ability of NP to elicit estrogenic responses through indirect mechanisms of action involving the modulation of endogenous steroid hormone concentrations. Sexually mature male common carp (Cyprinus carpio) were exposed to aqueous NP concentrations ranging from <0.05 to 5.4 microg NP/l for 28-31 d. Approximately 0.5-3.5 ppm of NP was detected in pooled plasma samples or tissue samples from the carp studied. NP exposure did not significantly increase plasma concentrations of 17beta-estradiol (E2), testosterone (T) or vitellogenin (VTG). Excluding outliers, plasma E2 concentrations ranged from <175 to 700 pg E2/ml. T concentrations ranged from 940 to 24,700 pg T/ml plasma. The greatest VTG concentration detected was 52 microg/ml. One-third of the plasma samples tested contained <1 microg VTG/ml. Overall, the results of this study did not support the hypothesis that exposure to waterborne NP can modulate concentrations of steroid hormones in the plasma of sexually mature male carp. The results did, however, raise a number of questions regarding the utility of estradiol equivalent (EEQ) estimates as a means of predicting in vivo effects of estrogenic substances. Furthermore, they provide information regarding the concentrations and variability of E2, T, and VTG in the plasma of sexually mature male carp, which may aid in design and interpretation of future studies.

In vitro bioassays to evaluate complex chemical mixtures in recycled water.

With burgeoning population and diminishing availability of freshwater resources, the world continues to expand the use of alternative water resources for drinking, and the quality of these sources has been a great concern for the public as well as public health professionals. In vitro bioassays are increasingly being used to enable rapid, relatively inexpensive toxicity screening that can be used in conjunction with analytical chemistry data to evaluate water quality and the effectiveness of water treatment. In this study, a comprehensive bioassay battery consisting of 36 bioassays covering 18 biological endpoints was applied to screen the bioactivity of waters of varying qualities with parallel treatments. Samples include wastewater effluent, ultraviolet light (UV) and/or ozone advanced oxidation processed (AOP) recycled water, and infiltrated recycled groundwater. Based on assay sensitivity and detection frequency in the samples, several endpoints were highlighted in the battery, including assays for genotoxicity, mutagenicity, estrogenic activity, glucocorticoid activity, arylhydrocarbon receptor activity, oxidative stress response, and cytotoxicity. Attenuation of bioactivity was found to be dependent on the treatment process and bioassay endpoint. For instance, ozone technology significantly removed oxidative stress activity, while UV based technologies were most efficient for the attenuation of glucocorticoid activity. Chlorination partially attenuated genotoxicity and greatly decreased herbicidal activity, while groundwater infiltration efficiently attenuated most of the evaluated bioactivity with the exception of genotoxicity. In some cases, bioactivity (e.g., mutagenicity, genotoxicity, and arylhydrocarbon receptor) increased following water treatment, indicating that transformation products of water treatment may be a concern. Furthermore, several types of bioassays with the same endpoint were compared in this study, which could help guide the selection of optimized methods in future studies. Overall, this research indicates that a battery of bioassays can be used to support decision-making on the application of advanced water treatment processes for removal of bioactivity.

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 Part II: Bioaccumulation potential and persistence Part III: Acute and subchronic or chronic toxicity Part IV: Results from representative chemicals, sensitivity analysis, and discriminatory power Part IV: 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.

Examination of reproductive endpoints in goldfish (Carassius auratus) exposed in situ to municipal sewage treatment plant effluent discharges in Michigan, USA

Effects of representative mid-Michigan (USA) wastewater treatment plant (WWTP) effluents on the reproductive physiology of common goldfish (Carassius auratus) were assessed in situ by measuring plasma concentrations of vitellogenin (VTG), 17 beta-estradiol (E2), and testosterone (T), and evaluating gonad histology. Caged adult male and female goldfish were exposed for six weeks to WWTP effluents. One riverine site and one lacustrine site were included as references for comparison to WWTP sites. There was differential growth and gonadal development among locations, which confounded the interpretation of biomarker responses. A linear contrast model was developed by analysis of covariance, and adjusted values were developed for concentrations of VTG, E2, and T in the plasma of both male and female fish. In general, VTG concentrations were significantly less in male than in female goldfish. Most concentrations of VTG in male goldfish were less than the method detection limit. There were no significant differences in plasma VTG of either male or female goldfish among locations or between sites at WWTPs and reference sites. Concentrations of E2 in the plasma of female goldfish were similar among WWTP sites, all of which were less than in females at a pond reference location. Concentrations of E2 in the plasma of male goldfish were similar at all WWTP locations, except for one, where they were greater. No consistent trends in hormone concentrations or gonadal histology could be attributed to putative endocrine disrupter exposure in WWTP effluents. The results indicate that the risk for estrogen agonist exposure below these mid-Michigan WWTPs is small.

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 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 I: Structure of the scoring and ranking system [ESPR 7 (1) 51-61 (2000)] Part II: Bioaccumulation potential and persistence [ESPR 7 (2) 115-121 (2000)] Part III: Acute and subchronic or chronic toxicity Part IV: Results from representative chemicals, sensitivity analysis, and discriminatory power ()

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.