MONITORING OF ORGANOTINS IN LA SPEZIA GULF .1. ANALYTICAL METHODS AND PRELIMINARY-RESULTS (SUMMER 1989)

As part of a general monitoring program, organotins are to be determined in water, sediments and mussels for 2 years in order to study the environmental fate of these compounds. In this paper, two analytical methods have been optimized, with particular attention paid to their suitability to field conditions, and tested on seawater samples. The first method is based on enrichment on graphitized carbon black, separation on silica-gel, and graphite furnace atomic absorption spectrophotometric detection. The second method is based on hydride generation with simultaneous liquid-liquid extraction and flame photometric gas chromatographic detection. The results of the first water sampling (August-September) are reported. Concentrations of tributyltin were found to be low (< 10 ng l-1) and the hypotheses of discontinuous emission and a seasonal minimum will be verified in the next sampling programmed for winter and spring.