5.3 RECX3MENDATIQNS FOR FUTURE RESEARCH 



In order to develop sound policy and regulatory actions, policy and 

 decision makers need clear statements of facts and problems. The 

 scientific community cannot at the present time predict what the 

 consequences to the environment would be for any given control strategy. 

 The experience of regulatory actions in the United Kingdom is 

 illustrative. The initial attempt was to reduce TBT loadings in the 

 environment by a combination of public education and a limitation of the 

 tin content of paints an a weight/percent basis. The result was a 

 dramatic 50% reduction in the concentrations of TBT in the water column. 

 However, that reduction was insufficient to bring the TBT loadings below 

 the levels known to be harmful to the most sensitive species. Therefore, 

 a second, more stringent round of legislation was required to protect the 

 environment. The use of TBT in any paint applied to boats smaller than 25 

 meters length was prohibited (with the exception of alundnum-hulled 

 vessels) . The results of the second restriction on TBT paint use have not 

 yet been determined. 



At present, the U.S. Congress and many of the coastal states have adopted 

 or are considering legislation and/or regulations that should reduce 

 inputs of TBT to the marine environment. However, no legislation is being 

 considered that will totally eliminate organotin paint usage. Owing to 

 the serious public concern about the problem, TBT contamination in 

 estuaries will continue to be a management and research issue, even after 

 legislation is passed and strategies have been implemented to 

 significantly reduce or eliminate certain organotin sources. Various 

 aspects relating to the sources, fates, and effects of TBT in the marine 

 environment are still not well understood or well documented. Therefore, 

 research and monitoring activities to address these information gaps are 

 necessary and should continue in the future. 



A summary of the highest priority areas which continuing research, 

 development, and monitoring should address is as follows: 



o Identify specific and critical exposure pathways of TBT to 

 organisms at risk. In particular, the role of the surface 

 microlayer, suspended and bottom sediments, pore water, and 

 microorganisms. 



o Identify the mechanisms by which organisms concentrate TBT. 



o Identify and quantify key factors and mechanisms that control the 

 degradation of TBT. 



o Improve detection and analysis methods to provide rapid and 

 accurate measurements of butyl tin species in ng/1 concentrations. 



o Develop necessary Standard Reference Materials to allow 

 intercal ibration between laboratories and methods. 



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