STP1443: Establishing Cause-Effect Relationships for Chemical Stressors in Amphibians: Providing Adequate Data for the ERA

    Fort, DJ
    President and Research Scientist, Fort Environmental Laboratories, Stillwater, OK

    McLaughlin, DW
    President and Research Scientist, Fort Environmental Laboratories, Stillwater, OK

    Pages: 14    Published: Jan 2003


    Abstract

    Most studies with amphibians in the past have been designed to address either the effect or the potential cause. Thus, data collected may provide suitable documentation of field effects on local populations with little information on causality, or the data may provide suitable information on possible causes with little concrete explanation of effects on the local populations. In order to establish such a relationship at this level, a study must be designed to answer two primary questions. First, what is the effect on the local population? Second, what factors are causing this effect? To establish an effect on a local population of amphibians, population characteristics must be surveyed. This survey should include information on habitat suitability, life stage distributions, and reproductive and developmental success. Establishing the cause of the noted effects requires the collection of adequate field-based ecotoxicological data combined with well-designed and highly controlled laboratory studies, ultimately providing adequate lab-to-field extrapolation potential. Field-based ecotoxicological data can be collected using a combination in situ exposure and evaluation at various life stages, and laboratory examination of specimen collected from the field at appropriate life stages. More controlled laboratory-based studies involving the culture of indigenous species under simulated field exposure conditions should also be considered. Cross-over studies in which organisms collected from uncontaminated areas are cultured under contaminated conditions, and those from contaminated locations are cultured under uncontaminated conditions to help establish exposure and impact scenarios. Appropriate chemical analysis of environmental samples including water, sediment, soil, and tissues from field collected and laboratory-reared specimen should be performed to determine exposure concentrations relative to the effects observed in individuals and accumulation potential. Highly controlled spiking studies can then be performed to help confirm potential causes of the effects observed. Overall, in many cases a combination of parallel field and laboratory studies can be used to provide adequate data to establish causality

    Keywords:

    amphibians, ecotoxicology, risk assessment, lab-to-field extrapolation, in situ, study design


    Paper ID: STP11185S

    Committee/Subcommittee: E47.04

    DOI: 10.1520/STP11185S


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