COPPER LOADING ASSESSMENT FROM IN-WATERHULL CLEANING FOLLOWING NATURAL FOULINGSHELTER ISLAND YACHTBASIN, SAN DIEGO BAYSAN DIEGO, CALIFORNIA

摘要

The sources of contaminates to the coastal marine environment are of increasing concern to thoserntasked with establishing Total Maximum Daily Loads (TMDLs). Shelter Island Yacht Basinrn(SIYB) in San Diego, California has a recently promulgated TMDL for dissolved copper.rnRecreational vessels are typically painted with copper-containing hull paint to inhibit marinernfouling organisms. The passive input of copper to SIYB from anti-fouling paints has recentlyrnbeen studied. The objective of this study was to quantify both the dissolved and particulaternfractions of copper emitted from copper-based anti-fouling coatings in situ as a result of routinernactive hull cleaning of recreational vessels. To accomplish this, in situ samples were collectedrnusing a specially designed enclosed chamber. Three different hull-cleaning methods were testedrnusing two common paint formulations after one month and three months of natural fouling. Thernmethods included minimally abrasive “best management practices” (BMPs) using a soft carpet, tornmore abrasive scouring pads and brushes.rnHull cleaning generated an average emission rate of 10.0 μg/cm~2/event of dissolved copperrnfollowing one month of natural fouling. This compares similarly to an estimated 8.5 μg/cm~2/eventrnthat was calculated in a related technical report (RWQCB, 2005). On a mass basis, the particulaterncopper loading from recreational vessels was estimated at 2,080 kg/year in SIYB. As a potentialrnlong term source in sediments, additional study is warranted to accurately assess the true copperrnloading on bottom sediments and potential impact to benthic life within SIYB.