Contamination of a boatyard for maintenance of pleasure boats

Abstract

Purpose: The object of this study was to study a boat maintenance facility by investigating the degree of contamination and assessing how leachate water from soil affects organisms from three trophic levels. Materials and methods: Surface and subsurface (20-cm depth) soil samples were collected in a typical boatyard (200 boats, 12,000 m2) at a 70- (station A), 90- (station B), 120- (station C) and 160-m (station D) distance from the shoreline. Three replicate samples, ∼10 m apart, were taken at stations A, B and C, respectively, and one replicate was taken at station D (i.e. altogether 20 samples with 10 at surface and subsurface, respectively). The total copper (Cu), lead (Pb), tin (Sn) and zinc (Zn) concentrations were determined for all replicates. Pooled samples from the respective stations were used for analysis of organotin compounds, irgarol and polyaromatic hydrocarbons. Leachate waters were produced from the pooled samples and used for toxicity testing with the bacterium Vibrio fischeri, the macroalga Ceramium tenuicorne and the crustacean Nitocra spinipes. Results and discussion: Very high concentrations of Cu, Pb, Zn were detected, with maximum values of 16,300, 6,430 and 18,600 mg/kg dw, respectively. Organic hazardous compounds were found in high concentrations with maximum values of 37, 27 and 16 mg/kg dw for tributytin (TBT), dibutyltin (DBT) and triphenyltin (TPhT), respectively. All pollutants exceeded existing guidance values for both sensitive land use and less sensitive land use by several factors, in both surface and subsurface soil. The least and worst cases of total amount of TBT (12 000 m2 and 0.2 m depth) were estimated to be 10 and 122 kg of TBT. Leachates were shown to be toxic in all three test organisms. Conclusions: Several known hazardous pollutants were found in boatyard maintenance areas and they exceeded recommended guidance values by several factors. Leachates were shown to be toxic to test organisms of several trophic orders. This underlines that boat maintenance facilities in general should be better regulated to minimize further exposure to humans and spread of contaminants in the environment. The amounts of contaminants accumulated in these areas call for investigations of how remediation should be performed.