EVALUATION OF SEDIMENTS FROM THE ASHLAND HARBOR LAKEFRONT SITE FOR TOXICITY TO HYALELLA AZTECA, PIMEPHALES PROMELAS, CHIRONOMUS DILUTUS, AND LUMBRICULUS VARIEGATUS EXPOSED IN A VARIETY OF BIOASSAYS

Abstract

The University of Wisconsin-Superior’s Lake Superior Research Institute (LSRI) contracted with URS to evaluate sediments from the Ashland Lakefront site for toxicity toward several species of benthic invertebrates and one species of fish. Sediment samples were collected from a total of six reference stations and eight Site stations. The contaminated sediment from one of the sites was diluted with dilution sediment to obtain a concentration gradient. The following tests were conducted: a 28-day exposure of Hyalella azteca, a 21-day exposure of Hyalella azteca to reference sediment only, a 28- day exposure of Hyalella azteca to new reference sediment and previous non-reference sediment, a ten-day exposure of Hyalella azteca to a sediment dilution series under laboratory and ultraviolet light conditions with some treatments containing detritus, one seven-day solid phase fathead minnow exposure, one seven-day solid phase fathead minnow exposure under ultraviolet light, an early life stage Chironomus dilutus exposure, a Lumbriculus variegatus bioaccumulation study, and finally a sediment polycyclic aromatic hydrocarbon (PAH) equilibrium partitioning study. The endpoints of survival and growth were determined for most studies except for the bioaccumulation study and PAH equilibrium study. Only survival was used as an endpoint for the 21-day exposure of Hyalella azteca to the newly collected reference sediment.