Admissible concentration in biological material: an index of exposure to dichloromethane

In 2007, a new maximum admissible concentration value of 88 mg/m(3) was specified for dichloromethane (DCM) in the Polish list of admissible concentrations of harmful chemicals and dusts in the work environment atmosphere. The new value is four times higher than the former one (20 mg/m(3)), valid in Poland for 20 past years. At the same time, it was decided that the value of short term exposure limit (STEL) shall no longer be specified. Dichloromethane is a chemical which can be absorbed by routes other than respiratory, therefore, biological monitoring is required to ensure that the risk is not underestimated. Experimental data support the conclusion that volatile chloroorganic compounds, including dichloromethane, are excreted with urine in the unchanged form, and thus their absorption and exposure can be easily assessed. Concentration of dichloromethane in urine determined at the end of work shift is proposed in Poland as a specific index of dichloromethane exposure. Dichloromethane inhalation exposure at maximum admissible concentration of 88 mg/m(3) corresponds with biological exposure index (BEI) of 0.15 mg DCM/l urine. The BEI value proposed in Poland for DCM is compatible with that specified by the American Conference of Governmental Industrial Hygienists (ACGIH).