Copper accumulation from antifouling paints in five marinas on Puget Sound

Marinas have been shown to contribute elevated levels of metals to marine waters, copper (Cu) in particular. The Cu comes primarily from antifouling paints which are designed to discourage biofouling (barnacles, mussels, and other organisms) of boat hulls. In 2011 the Washington State Legislature passed SSB5436 to phase out Cu in marine antifouling paints. This legislation states that new recreational vessels with Cu-containing bottom paint may not be sold in the state after January 1, 2018. This study provides baseline data for Cu in five marinas of different configuration and size within Puget Sound and assesses potential impacts to marine biota. Four sampling events were conducted between September 2016 and June 2017. Sample media included: water (dissolved and total fractions of metals), sediments (suspended and bottom), and biota (transplanted mussels and biofilms). We found strong evidence, across sample media that Cu accumulate inside marinas to higher levels than outside marinas, regardless of marina configuration. Marinas that are more enclosed, where water is slower to flush in and out, accumulated higher levels of Cu than more open marinas. However, concentrations of Cu were rarely high enough to be above the state water quality criterion for acute impacts to aquatic life. Sediment Cu was also not above the state criteria for the protection of benthic invertebrates. This study provides an adequate baseline dataset to measure progress as a result of recent legislation towards the reduction of Cu to Puget Sound from marinas