You are here:
MINIATURIZED SEDIMENT PROCEDURES FOR ASESSING TOXICITY USING MARINE AND FRESHWATER AMPHIPODS AND EMBRYO/LARVAL FISH
Citation:
Lazorchak, J M. AND M E. Smith. MINIATURIZED SEDIMENT PROCEDURES FOR ASESSING TOXICITY USING MARINE AND FRESHWATER AMPHIPODS AND EMBRYO/LARVAL FISH. Presented at Society of Environmental Toxicology and Chemistry, Nashville, TN, November 12-16, 2000.
Impact/Purpose:
The current goals of this task's research are to (1) develop miniaturized sediment exposure methods using selected marine and freshwater fish and amphipods that can be used for screening contaminants in sediments from surface waters and remediation studies and (2) to modify present sediment toxicity methods to include molecular methods for the detection of sublethal changes associated with exposure to contaminants.
Description:
Sediment toxicity tests are needed that can be conducted with less sediment volume and fewer organisms. Bench scale remediation techniques often produce less sediment than is required to perform the standardized sediment methods and the excess sediments that are generated present a potential hazardous waste disposal issue. Minimizing sample volumes reduces the time required to collect samples, prepare samples (sieving) and enumerate organisms at the end of the test. To address these issues we have modified existing USEPA methods that use significantly less sediment and fewer organisms than the standard toxicity tests and developed two alternative methods. Freshwater methods include a 7-day amphipod, Hyalella azteca method and 7-day fathead minnow (Pimephales promelas) embryo-larval hatching method and two marine methods, a 10-day amphipod, Ampelisca abdita, and a 7-day sheepshead minnow (Cyprinodon variegatus) embryo/larval method. We have modified the existing USEPA methods for the two amphipod tests and adapted the USEPA embryo/larval aqueous methods for sediment testing. In the freshwater amphipod test we have reduced the volume of sediment from 100 ml to 17 ml and reduced the number of organisms from 80 to 20. In the marine amphipod method we reduced the sediment volume from 175 ml to 40 ml and reduced the number of organisms from 100 to 50. Results on contaminated and uncontaminated sediments indicate that the miniaturized methods are comparable to the standardized test methods and the amount of time to prepare the samples and conduct the tests is significantly reduced. The miniaturized test methods can be used when regulatory program requirements are not required.