228a - How can biomonitoring support occupational hygiene in a further reduction of exposure to hexavalent chromium? – Results from the HBM4EU chromate study

Occupational exposure to hexavalent chromium (Cr6) deserves attention because of the evidence for an associated health risk, including cancer. As part of HBM4EU a study was conducted with the main aim to find out what biomonitoring can add to further improve work practices to reduce exposure to Cr6. In 2019, a cross-sectional study was carried out in 399 chrome workers and 203 controls in nine European countries. Total chromium (TCr) blood and urine was measured and TCr in erythrocytes was used as a measure of intracellular Cr6. Cr3 and Cr6 were analysed in inhalable and respirable dust collected from the breathing zone and for the assessment of dermal exposure hand wipes were collected. The biomonitoring results showed that production workers were higher exposed than controls. The highest exposures were found in chrome plating. Urinary TCr was associated with inhalation Cr6 exposure in a group of 57 plating workers (Spearman’s correlation coefficient of 0.783). An air concentration of 1 µg Cr6/m3 in the breathing zone corresponds to approx. 2 µg TCr/g creatinine in urine. Mechanisation of chrome baths was associated with lower TCr levels in urine compared to manual operation. An association was observed between TCr contamination on the hands and urinary TCr. Storing (used) work cloths in lockers was associated with higher urine TCr. In conclusion, biomonitoring results indicate that Cr6 can also be absorbed via other and indirect routes than (only) inhalation. There may be opportunities for occupational hygiene interventions leading to a further reduction of exposure to Cr6. Presented on behalf of the HBM4EU occupational study project team.