Priority Substances List Assessment Report for Non-pesticidal organotin compounds

4.0 Recommendations for Research and Evaluation

1. It is recommended that additional data be generated on the physical/chemical properties of non-pesticidal organotin compounds, in order to characterize partitioning in the general environment more fully. This research is considered to be of high priority.
2. It is recommended that concentrations of organotin compounds be determined in drinking water supplies distributed through PVC pipe in which they are used as stabilizers. Additional data are also needed on concentrations of organotin compounds in all foodstuffs, particularly those used as stabilizers in PVC packaging and those used as veterinary drugs in poultry. This research is considered to be of high priority.
3. Acquisition of additional data on sources and concentrations of non-pesticidal organotin compounds in the Canadian environment is also recommended, including monitoring of:
   
   
   • effluents from the largest PVC-fabricating plants in Canada;
   • sewage treatment plant influents, effluents, and sludges;
   • landfill leachates; and
   • fresh water, seawater, sediment, and aquatic biota.
     This research is considered to be of medium priority.

If warranted, based on consideration of additional data on sources and concentrations acquired as recommended, the following studies may also be desirable:

• subchronic toxicity studies on monobutyltin, mono- octyltin, and dioctyltin compounds;
• carcinogenicity bioassays on monomethyltin, dimethyltin, and dibutyltin compounds in which non-neoplastic endpoints, such as organ weight changes and biochemical and hematological effects, are also examined in two species of experimental animals.