Objective To identify occupational hazardous substances in flotation agents used by coal washeries, and to provide basis for measure and evaluation of occupational hazards.
Methods Air samples from working environment were collected using active carbon tube. The chemical toxicants in flotation agents were detected by gas chromatography-mass spectrometry and gas chromatography for qualitative and quantitative analysis.
Results The main chemicals detected in the flotation agents were 2-bromoheptane, cis-3-methyl-2-pentene, 2, 4-hexadiene, benzene, 1, 1, 3, 3-tetramethyl-propadiene, 4-methyl-1, 4-hexadiene, 4, 4-dimethylcyclopentene, toluene, ethylbenzene, o-xylene, 1-methyl-2-isopropyl-benzene, and (R)-(+)-limonene. The time-weighted average (TWA) concentrations of benzene, toluene, ethylbenzene, 2, 4-hexadiene, and 4, 4-dimethylcyclopentene were 6.5, 10.8, 2.3, 13.7, and 14.0 mg/m3, respectively. The corresponding maximum short-term exposure limit (STEL) concentrations were 16.0, 36.0, 9.0, 16.9, and 17.2 mg/m3, respectively.
Conclusion The major chemicals exposed by the inspection workers in the coal flotation section include benzene, toluene, ethylbenzene, 2, 4-hexadiene, 4, 4-dimethylcyclopentene, and xylene. The TWA concentration of benzene exceeds the national standard, and the STEL concentration of benzene is 1.6 times that of the national standard, but concentrations of toluene, ethylbenzene, and o-xylene meet the national standards.
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