Environmentally-Mediated Endocrine Disruption in Estuarine Crustaceans: A 3-Taxon Multi-Generational Study of Sediment-Associated EDC Effects from the Genetic to Population LevelsEPA Grant Number: R827397
Title: Environmentally-Mediated Endocrine Disruption in Estuarine Crustaceans: A 3-Taxon Multi-Generational Study of Sediment-Associated EDC Effects from the Genetic to Population Levels
Investigators: Chandler, G. Thomas , Ferry, John L. , Fulton, Michael H. , Quattro, Joseph M. , Scott, Geoffrey I. , Wirth, Edward F.
Institution: University of South Carolina at Columbia
EPA Project Officer: Carleton, James N
Project Period: April 1, 1999 through March 31, 2002
Project Amount: $1,265,102
RFA: Endocrine Disruptors (1999) RFA Text | Recipients Lists
Research Category: Economics and Decision Sciences , Endocrine Disruptors , Health , Safer Chemicals
The objective of this study is to construct a coupled abiotic-EDC transformation/ estrogenic impact model of two classes of four known or suspected EDCs contrasted in 3 ecologically-important species: grass shrimp, amphipods and benthic copepods. This model will assess (1) mechanisms by which environmental processing of EDCs affect their toxicological properties in the environment, and (2) how molecular/ cellular manifestations of these EDCs are expressed and ultimately linked to crustacean population fitness and maintenance at the recruitment and population-genetic levels. This research will help the USEPA to evaluate strengths of linkages between EDC molecular/cellular and genetic disruption and subsequent outcomes at the population resource level. The hypothesis being tested is: Contaminants such as Endosulfan and PAH photo-activation products disrupt normal neuro-endocrine:hormonal pathways and induce mediated effects at the molecular -> cellular -> organism -> population levels in crustaceans, and these effects are manifested in a conserved fashion that allows development of robust ecological risk assessment models.
The proposed research will assess the ecotoxicological effects of EDCs from the molecular to population levels using 3 ecologically-important crustacean models: grass shrimp (Palaemonetes pugio), amphipods (Leptocheirus plumulosus) and copepods (Amphiascus tenuiremis & Microarthridion littorale). Two classes of compounds will be evaluated for their EDC potential including: (1)The organochlorine insecticide, endosulfan and ES sulfate, which has been responsible for more fish kills than all other pesticides combined in the SE USA and has been implicated as a potential EDC in in vitro mammalian lab tests; and (2) two ubiquitous PAHs, with (6- hydroxychrysene and 1-hydroxypyrene) and without (chrysene, pyrene) photo-activation . Grass shrimp, amphipods and copepods will be exposed in laboratory toxicity tests and evaluated for a suite of EDC-specific biomarkers including methyl farnesoate, vitellin, and edcysone, along with survival, reproduction, and imposex metrics. The proposed grass shrimp, amphipod and copepod bioassay protocols will provide the USEPA with 3 linked crustacean models in which a suite of key neuro-endocrine biochemical biomarkers can be assayed to determine if the mode of action for a given chemical is indeed via a hormone mediated:related pathway, in addition to a multi-generational assay which is predictive of potential population-level effects. Multi-generational effects will be assessed via a multi-endpoint population structure and life-table approach. Also, genetic biomarker research will be conducted to evaluate the utility of the GABA(A) receptor in these crustacean models as a potential complimentary biomarker of EDC exposure/effects. The frequency of cyclodiene resistance in crustacean populations will be assessed in endemic crustacean populations residing in agricultural areas where endosulfan is extensively used, and then correlated with cellular, organismal and population level laboratory endpoints. An impacted field-population assessment is proposed to assess both biochemical and genetic effects as well as population-level impacts to grass shrimp in a pesticide impacted region of South Florida, and in an agriculturally -contaminated site in SC. Salt-marsh mesocosm exposures also will be conducted as a controlled extension of field research. This will further aid interpretation of observed field population effects in terms of discerning EDC versus biogenic and natural environmental effects.
Results of this study will provide EPA with great insight into the complex ecotoxicological effects of EDCs in crustaceans. The proposed research is unique in that it will assess EDC ecotoxicological effects from the molecular to population levels in an extremely important invertebrate group -- both ecologically and commercially. This kind of multidisciplinary research is essential if we are ever to determine the interrelationships of EDC effects at multiple levels of biological organization and their linkages to resource protection at the population level. The biomarker research proposed will identify a specific suite of markers which could be used by EPA to identify potential EDC effects on crustaceans in monitoring programs, and also in testing programs for pesticide registration and toxic substances. The genetic biomarker research will evaluate the utility of the GABA(A) receptor as a potential complimentary biomarker of EDC exposure/effects which could be applied in monitoring programs to determine the areal extent of cyclodiene EDC impacts in the field. The proposed grass-shrimp: amphipod:copepod testing approaches will provide EPA with new crustacean models in which a suite of key neuro-endocrine biochemical biomarkers may be linked to a suite of multi-generational endpoints and field assays to predict potential population level risks. Knowledge of linkage strengths between molecular-organism-population effects and EDC's is essential in developing risk assessment approaches for EDCs. This project in toto will provide the USEPA with invaluable insight for the formulation of appropriate risk assessment protocols for EDCs in aquatic ecosystems.