Antifouling Paint Booster Biocide Contamination in UK Marine Sediments

The proposed International Maritime Organization (IMO) ban on tributyltin (TBT) as an antifouling paint biocide, will raise the inevitability of the increased use of alternative paints containing copper and organic booster biocides. Although the fate of TBT in marine sediments has been extensively studied, very little work has been performed to assess the accumulation of organic booster biocides in sediments. A survey was conducted to determine concentrations of TBT, Irgarol 1051, the Irgarol 1051 metabolite GS26575 (2-(tert-butylamino)-4-amino-6-(methylthio)-1,3,5-triazine; also referred to as M1) and diuron in coastal and off-shore sediments. TBT was consistently determined at the highest concentrations and was detected in all sediments collected from Southampton Water, UK, along with the TBT degradation product dibutyltin (DBT). Irgarol 1051 was detected (0.01-0.11 μg/g) in some sediments collected from marinas, where high concentrations of these compounds have been measured in surface waters. The Irgarol 1051 metabolite 2-methylthio-4-tert-butylamino-6-amino-s-triazine (M1/GS26575) was only detected at a few locations at concentrations <0.001 μg/g, although higher concentrations were determined in surface waters (13-99 ng ng l). Diuron, thought to be present in the form of antifouling paint particles, was determined at a concentration of 1.4 μg/g in an enclosed marina. All analytes were found to be below the limit of detection in the sediments collected off-shore. The potential accumulation in sediments of the other two booster biocides currently used in the UK, zinc pyrithione and dichlofluanid, are also discussed. (C) 2000.