02-04-2002 Port of Houston Expansion Review Committee Minutes

Browse Search

• 11 aquatic biota. The toxic effects of all metal-based boosters need further evaluation. Summary of Risk Assessment Results. To date, no scientifically rigorous risk assessments have been conducted for alternative antifouling paint systems. Kramer (1998) conducted an ecological risk assessment of copper and adichloro-isothiazolone, but many of the assumptions of exposure and effects are questionable. For example, insufficient information is presented to adequately evaluate the exposure modeling of adichloro-isothiazolone that was required. The effects characterization was fundamentally flawed because acute toxicity data were used to determine effect levels; however, as mentioned above, chronic toxicity data are more appropriate because the leaching of biocide from paint represents a continuous source. Lord et al. (1997) assessed the aquatic life risks associated with a triazine, but the results are questionable because it appears the compound's toxicity and persistence were underestimated. For example, Pearce's publication in the New Scientist indicates that assessments by the pesticide division of the Swedish inspectorate concluded that triazine degrades "very slowly" in aquatic environments and is likely to accumulate in water and sediments, and that it tends to accumulate in fish (Readman 1996). There are no known aquatic life risk assessments of alternative antifoulants in the peer reviewed scientific literature. Conclusions As stated in the introduction, the IMO MEPC has developed an initiative to ban all antifouling systems exhibiting harmful effects on the marine environment and in the interim, to use antifoulants that elicit the fewest possible effects. Risk assessment is the most useful tool to determine whether a chemical does or may exhibit harmful effects on the environment, and comparative risk assessment is the most useful tool to determine which chemical poses the smallest risk to the environment. As yet, no comparative risk assessments have been conducted between marine antifoulants. Comparative risk assessments of TBT and alternative antifoulants are currently difficult due to the lack of analytical methods, limited monitoring data, and little information about the fate and toxicity of these alternative compounds (Voulvoulis et al. 1999). It should be emphasized that the alternative antifoulants have not been studied extensively and have the potential to cause environmental damage because they are designed to be toxic to a range of marine organisms (Voulvoulis et al. 1999). In fact, based on the meeting notes from the OSPAR convention in 18-22 October 1999 the INPUT and ASMO working_groups concluded that TBT alternatives seem to have the same types of unwanted environmental effects as TBT (O5PAR