Research Product

The U.S. Environmental Protection Agency (EPA) and the National Cancer Inst. (NCI) have major responsibilities for determining the fate and risks of carcinogenic agents in the natural environment. Under the auspices of EPA/NCI, the Carcinogen Research Team at the U.S. EPA Lab, Gulf Breeze, has a major role in investigating the fate, effects, and risks of carcinogenic agents in the aquatic portion of the biosphere. In regard to this role, there is a need for practical, experimental exposure systems for the short term, and long term exposure of fishes and invertebrates in order to evaluate their responses to environmentally significant carcinogens. We have designed and tested an adaptable, aquatic laboratory system for flowing water or static water assays of carcinogenic or suspect carcinogenic agents against marine fishes. We report here the design, results of long term tests, and the future uses of the system for determining the risks of carcinogenic agents in the aquatic environment, and as a system complementary to mammalian assay systems, but which permits the phylogenetic expansion of carcinogen assay methodology. A pilot test of the described system has been completed. This test utilized flowing filtered, estuarine water, controlled water temperature, controlled photo period, controlled nutrition of test species, oxygen concentration monitoring, and various life cycle stages of the test fish, the sheepshead minnow, Cyprinodon variegatus, and the suspect carcinogenic herbicide, trifluralin. Continuous exposures to 1 to 5 µg/l trifluralin were conducted with zygote, thru embryogenesis to adult stages of the fish.