Summary (1995-2000)

The primary goal of this program is directed toward the development of methodologies for assessing the potential toxicity of chlorinated organic compounds. The program concentrates on research regarding chlorinated organic compounds due to their importance as contaminants at Superfund and other hazardous waste sites. Existing evidence supports possible adverse human and environmental impacts from exposure to chlorinated organic compounds, even at low exposure levels. This program emphasizes human toxicology and toxicokinetics related to exposure to such chlorinated organic compounds, and specifically focusses on endocrine effects in both mammalian and non-mammalian species. The program consists of four individual projects (three biomedical and one nonbiomedical) and four support cores, including analytical chemistry, histology, epidemiology/biometrics, and training/outreach.

Of the biomedical projects, one is identifying and characterizing factors, such as intestinal bioavailability and chemical interactions, that influence the bioavailability of substances (specifically tetrachlorodibenzo-p-dioxin (TCDD), trichlorobenzene (TCB), and benzo(a)pyrene) which are usually found at Superfund sites. Another project is investigating the mechanisms of action of TCDD and PCBs on placental-uterine function. This study is based on the hypothesis that TCDD and PCB's alter placental-uterine paracrine and autocrine networks which are important for trophoblast invasiveness, proliferation and hormone secretion, and uterine cell growth. A third project is assessing the toxicokinetics and human toxicology of dichloroacetate (DCA), which is present in chlorinated ground water and is considered to be a potential environmental hazard to humans. This research is providing information on human developmental toxicology of DCA with detailed studies of its effects on biochemical, opthalmological, reproductive, intellectual, and neurological indices.

The nonbiomedical project is directed toward understanding the effects of chlorinated hydrocarbons to wildlife at concentrations usually present in the environment. The project is studying how such compounds affect the reproductive and endocrine systems of three species of wildlife (alligators, large mouth bass, and brown bullhead catfish) living in a highly polluted lake in central Florida, Lake Apopka which is adjacent to the Tower Chemical Company Superfund Site. Because wildlife often act as sentinels of contaminant exposure for humans, the results generated from this research may help increase understanding of how chlorinated hydrocarbons harm human health.

The training and outreach core provides the means through which the overall research program can have a positive impact on the training of environmental health scientists. This core facilitates the dissemination of knowledge gained by the program's research to other scientists, government agencies, industry, and the community. Louisiana State University is currently collaborating on various aspects of this program's research efforts in order to further the advancement of knowledge regarding chlorinated organic compounds.