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The reduction of light intensity in bioluminescent bacteria upon exposure to toxic substances can be used for rapid screening of materials. Results are often comparable to more expensive standard bioassays.A commercially available system was used to determine the relative response of bioluminescent bacteria to a number of alkyltin compounds: R4Sn, R3SnX, R2SnX2, and RSnX3, where R = alkyl group and X = halide, Within a series of compounds differing only in the number of R groups attached to the central tin atom, the most toxic compound was always the trialkyltin compound. The greatest difference in toxicity was found in the butyltin series of compounds: tributyltin was -35 times more toxic than dibutyltin and -750 times more toxic than (mono)butyltin. When trialkyltin compounds were compared, the toxicity to these bacteria increased with the number of carbons in the alkyl chain: the tributyltin compounds are -150 times more toxic than trimethyltin compounds.

Optimized techniques for measuring butyltins at the sub-part-per-trillion (ppt; 1:101*) level in seawater and at the part-per-billion (ppb; 1:109) level in tissues and sediments are presented. Purge and traplhydride derivatization followed by atomic absorption (AA) detection was optimized to give better sensitivity than was previously attained for seawater, yielding environmental detection limits of 0.08-0.2 ng dm -3. Improvement in precision and reproducibility in measurement of butyltins in tissues and sediments was attained by adjustment of the concentration in an organic extract to minimize matrix effects and by use of internal standards. The tissues and sediments were homogenized and extracted with methylene chloride (CH2C12) after acidification. The butyltins in the organic layer were derivatized with hexylmagnesium bromide and analyzed by gas chromatography (GC) with a flame photometric detector (FPD). The absolute detection limits in tissues and sedimets were 0.1 ng for tributyltin (TBT), 0.12 ng for dibutyltin (DBT) and 0.29 ng for monobutyltin (MBT).