MP13 Aquatic Ecotoxicology
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(CAP-1117-086351) Impacts of Suspended Sediment on Aquatic Organisms.

Capper, N¹, Klaine, S¹, ¹ Clemson Institute of Environmental Toxicology, Pendleton, SC, USA

ABSTRACT- Land use change may result in significant amounts of soil migrating into aquatic streams during storm events. This soil, even in the absence of adsorbed contaminants, may be a significant stressor to aquatic organisms. In many parts of the US, total suspended solids (TSS) concentrations surpass 100,000 mg/L during storm events. The limited data on effects of suspended sediment concentrations has mainly focused on salmonids or ecosystem level consequences such as habitat alteration. Few studies have quantified the effects of suspended solids on water column organisms. These studies are needed since little physiological data is available on this subject. The purpose of this research was to determine the effects of suspended sediment concentrations on Daphnia magna and Pimephales promelas. Results of 7 d toxicity tests with D. magna in Kaolin suspensions indicated an LC₅₀ of approximately 100 mg/L. This value was considerably less than TSS concentrations common in many areas of the US and can be sufficient to elicit feeding inhibition and reproductive effects in Cladocerans. The experimental design for this research also included the use of natural sediments collected during storm events to facilitate the extrapolation of laboratory results to predict response in the field. Results of this research underscore the need to treat eroded soil as a water column contaminant.

Key words: suspended sediment, land use change, daphnia magna, sublethal