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- Lagerström, Maria, 1986-
(författare)
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Occurrence and environmental risk assessment of antifouling paint biocides from leisure boats
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of biocidal antifouling (AF) paints is the most common way to prevent fouling on leisure boat hulls. The main aim of this thesis was to investigate the pathways through which AF biocides, past and present, may reach the environment through their use on leisure boats and to improve the risk assessment of biocidal AF paints intended for amateur use. The work presented focuses mainly on the Baltic Sea, with emphasis on regulation and risk assessment procedures in Sweden. A new method was developed for the quantification of nowadays banned organotin compounds (OTCs) such as tributyltin (TBT) in paint flakes (paper I). OTCs were detected in hull paint scrapings from three countries around the Baltic Sea. Thus, historic layers of organotin paint on leisure boats may constitute as sources of TBT to the marine environment. Total tin was identified as an indicator for the presence of OTCs on boat hulls, allowing for quicker identification of vessels in need of remediation. Nowadays, most AF paints tend to contain high amounts of copper (Cu) and zinc (Zn). The use of AF paints was shown to cause exceedance of guideline values for these two metals in soil, sediment and water in various investigated marinas (papers II and IV). The pollution of boatyard soil was linked to hull maintenance activities carried out over unprotected ground (paper II). AF paints were also found to impact both the concentration and speciation of dissolved Cu and Zn in two Baltic Sea marinas, with increased concentrations as well as an increased proportion of bioavailable species as a function of an increased number of moored boats (paper IV). A new method utilizing X-Ray Fluorescence (XRF) was used to derive the release rates of Cu and Zn in the field for five commercially available AF paints for amateur use (paper III). Salinity and paint properties were found to be important parameters affecting the release. The in situ release rates were also found to exceed those derived with current standardized release rate methods. Given the high release rates, none of the studied paints should have been approved for the Swedish market. This finding likely explains the exceedance of guideline values for dissolved Cu and Zn in investigated Baltic Sea marinas (paper IV). In conclusion, there is a need for caution when authorizing new biocides as the phasing out of banned substances can be a lengthy process due to their continued presence in historic paint layers. Additionally, paint-specific release rates determined under conditions reflecting the intended use of the product should be used for a more realistic environmental risk assessment of AF paints.
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| 2. |
- Ytreberg, Erik, 1980-
(författare)
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Release rates and toxicity of metals from anti-fouling paints and the role of chemical speciation
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this doctoral thesis was to investigate and improve the risk assessment of anti-fouling paints. A new method, the Petri-dish method, was developed to determine release rates of copper and zinc from anti-fouling paints (Paper I). The release rates of zinc were substantially higher from the biocide-free leisure boat paints than from the biocide-leaching paints. In Paper II, the potential toxicity of paint leachates was assessed and the biocide-free paint proved to be the most toxic paint investigated. Zinc, a supposedly non-biocidal ingredient in copper-based and other antifouling paints, was found to contribute significantly to the observed toxicity of all leisure boat paints investigated. This means that risk assessment of an anti-fouling paint based on only the active biocidal ingredient in the formula is insufficient. A more holistic approach, based on hazard identification and dose-response assessment of anti-fouling paint leachate, with all ingredients taken into consideration, is recommended. This can be achieved by the Petri-dish method, which combines chemical analysis with ecotoxicological tests of paint leachates. In Paper III and IV, the effects of salinity and organic matter on copper bioaccumulation and toxicity to the red macroalga Ceramium tenuicorne were studied. Salinity had only a minor effect in ameliorating copper toxicity, whereas the organic matter concentration had a significant effect in reducing the bioavailability and hence copper toxicity at all salinities tested. Copper uptake and bioaccumulation by C. tenuicorne showed that the macroalga could access a sizeable fraction of organically-complexed copper in addition to Cu2+, when Cu2+ concentration to the cell membrane is diffusion limited. This observation implies that the setting of environmental quality standards (EQSs) for copper and other metals through the Biotic Ligand Model (BLM) is inappropriate in predicting copper uptake and hence toxicity to C. tenuicorne.
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