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College

College of Science and Engineering

Major

Biology

Faculty Mentor

Kristin Hultgren

Faculty Editor

Mark Jordan

Student Editor

Mackenzie Reed

Abstract

Throughout its history there has been heavy industrial pollution along the Duwamish Waterway in Seattle, Washington. Industrial and urban activities such as dredging, runoff, and aqueous waste production can have damaging effects on marine organisms, as the deposited contaminants, such as heavy metals, accumulate in sediment. Despite the well-documented history of lead contamination in the Duwamish Waterway, the effect of such contamination on aquatic organisms has scarcely been studied. This paper investigates the impact of sediment contaminants on the benthos by examining commonly found invertebrates in Seattle, Washington. The benthos is defined as the flora and fauna living on and in the bottom of sediments of a body of water. We examined the lethal and sub-lethal effects of lead contamination on three benthic crustaceans (Idotea wosnesenskii, Gnorimosphaeroma oregonensis, and Hemigrapsus oregonensis) along two sites on the Duwamish Waterway of known high contaminant levels. We then compared these sites to two other sites having known low contaminant levels. Despite significant differences in lead and copper sediment contamination, there were few measurable effects of heavy metal contamination among populations of I. wosnesenskii and G. oregonensis. Higher proportions of brooding females at non-contaminated sites, significantly different only in the month of June, could suggest disturbance resistance in H. oregonensis. We also examined food preference of Fucus as a food source of isopods at the four sites. Isopods from contaminated sites appeared to have a stronger preference for contaminated Fucus, but after statistical analysis they did not differ significantly from the preferences of the isopods collected at the uncontaminated site. With this in mind, we urge a long-term environmental assessment examining sediment contamination in the Duwamish Waterway to learn how anthropogenic stressors in aquatic environments alter ecosystems for benthic organisms.

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