# Chlorierte Biphenyle: MAK-Begründung, Nachtrag

## TL;DR

The paper establishes a safe workplace air concentration for chlorinated biphenyls to protect fetal development.

## Contribution

A new conservative workplace air concentration for PCBs is derived based on plasma background levels and fetal risk considerations.

## Key findings

- A tolerable increment of 1.5 µg 6IC/l plasma corresponds to 0.0008 mg/m³ in air.
- Background plasma concentrations have decreased since 2010, suggesting a more lenient limit could be possible.
- Respiratory volume and exposure duration significantly influence internal exposure levels.

## Abstract

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.