Chlorinated biphenyls

The German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) derived a concentration in workplace air for chlorinated biphenyls (PCBs) 1336-36-3 which is without risk to the developing foetus (corresponding to Pregnancy Risk Group C). The derivation is based on the prerequisite for the classification in Pregnancy Risk Group C at 3.5 μg/l plasma for the sum of the 6 indicator congeners (6IC) PCB 28, PCB 52, PCB 101, PCB 138, PCB 153 and PCB 180. Assuming a background concentration of 2 μg 6IC/l plasma for women up to 45 years of age with data from about 2010, an increment of 1.5 μg 6IC/l plasma is thus tolerable. This increment was estimated to correspond to a total PCB concentration in air of 0.0008 mg/m3 measured as the sum of the 6IC multiplied by 5. This concentration represents a rather conservative estimate, as the background concentration in plasma has reduced since and a respiratory volume of 10 m3 has been assumed, which might overpredict the exposure at workplaces in PCB-contaminated office or public buildings. Additionally, age and duration of exposure are important determinants for the inner exposure. These factors should be considered when evaluating the measurement results.