[Biological monitoring of workers exposed to trimethyltin chloride].

Objective: To investigate suitable biomarkers for workers exposure to trimethyltin chloride (TMT-cl).
Methods: Urinary samples of 44 male workers from five TMT-cl occupational poisoning incidents were collected. Methyltin mercaptide stabilizers and waste plastics used in the incidents were also collected. The levels of TMT-cl in all the samples were determined by gas chromatography. The concentration of blood potassium for each poisonings was determined compared to control group (50 male workers of a food company), and the correlation between blood potassium and urinary TMT-cl were also determined.
Results: TMT-cl was detected in urine of all the poisonings. The results were (0.869 +/- 0.392) microg/L (severe poisoning), (0.963 +/- 0.482) microg/L (moderate poisoning), (0.716 +/- 0.384) microg/L (mild poisoning) respectively and the difference was statistically significant (P < 0.01). But the severity of the clinical status did not seem to be closely correlated to the level of urinary TMT-cl (F = 1.88, P > 0.05). In the severe poisonings, there were no differences in urinary TMT-cl on day 4 after poisoning from day 1 (P > 0.05). In contrast, urinary TMT-cl was decreased significantly on day 4 than on day 1 in mild and moderate poisonings (P < 0.01). On day 21, levels of urinary TMT-cl of all the poisonings were higher than those of the workers exposed to TMT-cl who had no clinical status (P < 0.01). Blood potassium levels of exposed group was 77.3% which was significantly lower than normal value (P < 0.01). The concentration of blood potassium was lower than normal value (3.5 mmol/L) and was correlated with the severity of the clinical status (F = 4.45, P < 0.05). Level of urinary TMT-cl of exposed group was negatively correlated with blood potassium (r = -0.4456, P < 0.01).
Conclusion: Level of urinary TMT-cl can be used as exposure biomarker of TMT-cl poisoning. Blood potassium is an early biomarker of effect for TMT-cl poisoning so as to find poisoning population early.