Grantee Research Project Results

Teratogenicity of Heavy Metals to Larval Chironomids

EPA Grant Number: R826106
Title: Teratogenicity of Heavy Metals to Larval Chironomids
Investigators: Moore, Barry C. , Schaumloffel, John , Filby, Royston
Institution: Washington State University
EPA Project Officer: Hahn, Intaek
Project Period: November 1, 1997 through October 31, 2000
Project Amount: $125,661
RFA: Exploratory Research - Environmental Biology (1997) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Biology/Life Sciences

Description:

For several decades, elevated rates of characteristic morphological deformities have been reported worldwide in populations of larval chironomids (midge flies) growing in polluted aquatic sediments. There is strong circumstantial evidence that heavy metals are among the causative agents inducing deformities in developing larvae (teratogenesis). Many researchers have pointed to chironomid deformities as a potentially sensitive and powerful bioassay for sediment contamination. This research address fundamental questions that must be answered in order to make the use chironomid deformities a practical tool for pollutant assessment in aquatic sediments.

Approach:

This project will test the ability of cadmium, zinc, lead and copper, singly and in combination, to induce characteristic deformities in larval chironomids. Chironomids (Chironomus tentans) will be raised under controlled laboratory conditions and will be exposed to sediment contaminants singly and in various combinations and concentrations. Deformities and deformity rates will be assessed at different larval developmental stages. Deformity morphology will be assessed as indicators of specific causative agent(s). We will quantify the metal body burdens and test the relationship with exposure. We will quantify the concentration of each metal that produces a 10% larval deformity rate (EC 10). The Toxic Unit Model (TU) Additivity Index (AI) Method will be employed to model interactive teratogenic effects of metals and to characterize these interactions as additive, synergistic or antagonistic.

Expected Results:

We expect to find that test metals will induce deformities and that teratogenisis will occur at different concentrations. It is likely that deformities will be manifested differently at various instar stages. We believe that the potential for synergistic or antagonistic is great and that the EC10, TU and AI models will be appropriate tools for describing and predicting teratogenic effects of metals on chironomids. This research will increase our basic understanding of biological and ecological impacts of heavy metal pollutants. This research is essential to realization of the potential of chironomid deformities and deformity rates for environmental assessments of polluted sediments. It will increase our knowledge of subletal effects of heavy metal pollutants and the ecological consequences of such effects. Ambient monitoring of heavy metals against a background of other contaminants will be potentially improved, as will the ability to rapidly, reliably and economically assess spatial distribution of heavy metal contamination over large areas. Long-term monitoring of restoration activities will be enhanced. The research will also contribute to better methods for identifying and assessing specific Pollutant sources and for monitoring aquatic abatement and cleanup efforts.

Supplemental Keywords:

water, watersheds, sediments, ecological effects, dose-response, teratogen, midges, chironomids, heavy metals, aquatic assessment, deformities, limnology, zoology, biochemistry, pollutant interactions., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Waste, Water, Toxics, National Recommended Water Quality, Ecological Indicators, Ecological Risk Assessment, Ecosystem Protection, Zoology, Ecosystem/Assessment/Indicators, Contaminated Sediments, exploratory research environmental biology, Ecological Effects - Environmental Exposure & Risk, Biochemistry, Limnology, Ecology and Ecosystems, bioassay, ecological effects, copper, lead, water quality, teratogen, contaminated sediment, deformities, cadmium, body burden, sediment bioassay, toxic unit model, ecological exposure, Zinc, chironomids, aquatic ecosystems, dose-response, heavy metal contamination

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.