Heavy metal contamination in Puget Sound and Lake Washington sediments and benthic invertebrates; a focus on the influence of road material on extent of metal concentration

Abstract

Heavy metallic elements are found naturally in nature, but have been released into soils, rivers, and bodies of water due to anthropogenic activity, increasing concentrations to levels potentially harmful to human and environmental health. Metals have been found to enter marine sediments though point sources such as mining, aquaculture, and shipping activity. Transportation runoff, including worn road material and brake dust, is a potential source of metal contamination that has not been studied to a great extent, particularly in the Puget Sound region. In this study, surface sediments from Lake Washington, the Lake Washington Ship Canal, and South Puget Sound were analyzed for heavy, relating samples to proximity to roads, with control sites chosen at locations further from road activity and runoff. Elevated metal contamination was found in all sampling sediments, particularly in copper, lead, and selenium, with Lake Washington and Shipping Canal sites exceeding those in Puget Sound. Benthic invertebrate matter was also analyzed; elevated nickel, lead, arsenic, and chromium were found, but with less consistency between sites. This study further emphasizes that heavy metals have permeated the sediments and benthic invertebrates of the region, though the degree to which road material influences this contamination remains inconclusive.