ABSTRACT
OBJECTIVE:
To establish the
occupational exposure limit for trimethyltin
chloride(TMT) in
workplace air.
METHODS:
According to the GBZ/T 210.1-2008 Guide for Establishing
Occupational Health Standards--Part 1
Occupational Exposure Limits for Airborne
Chemicals in the
Workplace, the relevant
literatures on
toxicology,
population epidemiology and foreign
occupational exposure limit of TMT were collected and analyzed. A total of 276
workers with TMT
occupational exposure were selected as the exposure group and 25
workers without TMT
occupational exposure were selected as the
control group.
Worksite survey of
occupational health and occupational
medical examination were carried out. Combined with the
literature data, the
occupational exposure limit of TMT in the
workplace air was calculated by using the 90% medical reference level(internal exposure limit) of the
urine TMT level of
workers who exposed to TMT without moderate
hypokalemia.
RESULTS:
The
time-weighted average of TMT in the
workplace air is 0.100 mg/m~3 and the
short-term exposure limit is 0.200 mg/m~3 in the
United States based on total organic
tin. The highest concentration of TMT in the
workplace air in
Germany is 0.005 mg/m~3. The
literature data analysis results showed that the incubation period of TMT
poisoning is mostly 3-6 days, and the main symptoms of TMT
poisoning are
hypokalemia in the early stage, followed by neuropsychiatric symptoms such as
headache,
memory loss and aggressive
behavior. The median(M) and the 0-100 th percentile(P_0-P_(100)) of exposure to TMT were 8.35(< 0.20-91.40) μg/m~3 in the exposure group. The individual TMT exposure level of
workers in different positions from high to low were crushing, granulation, withdrawal and assembly positions. The M(P_0-P_(100)) of urinary TMT level in the exposure group was 16.94(<0.50-591.14) μg/L. There was a positive correlation between the individual TMT exposure level and
urine TMT level in the exposure group(Spearman correlation coefficient=0.62, P<0.01). The
detection rate of
hypokalemia in the exposure group was higher than that in the
control group(26.1% vs 4.0%, P < 0.05). However, there was no significant difference in the
detection rate of moderate
hypokalemia between the two groups(3.3% vs 0.0%, P>0.05). The 90% medical
reference value of
urine TMT was 89.90 μg/L in
workers exposed to TMT without moderate
hypokalemia.
CONCLUSION:
In order to prevent acute
hypokalemia damage caused by TMT, we recommended that the
occupational exposure limit of TMT in the
workplace air should be set at 0.025 mg/m~3 in
China, and this limit should be the
maximum allowable concentration.