Comparative health risk of inhaled exposure to organic solvents, toxic metals, and hexavalent chromium from the use of spray paints in Taiwan

Abstract

The study investigated the exposure of spray painters to organic solvents, toxic metals, and hexavalent chromium over 21 working days in 2017. The results found these concentrations of 12 VOCs to be below the short-term exposure limit (STEL) established by the US Occupational Safety and Health Administration (OSHA). The mass concentration of total particulate matter (PM) exposure to workers was 20.01 ± 10.78 mg/m³, which exceeds OSHA's permissible exposure level of 15 mg/m³. The mean concentration of the total metals for all particle sizes was 109.1 ± 12.0 μg/m³, and those for lead (496,017.0 ng/m³) and iron (252,123.8 ng/m³) were the highest of metal elements. Significantly, the mean concentrations of Pb and As exceeded OSHA's permissible exposure limits (PELs) of 0.05 and 0.01 mg/m³, respectively. The total hexavalent chromium concentration was 1163.01 ng/m³, and the individual particle sizes (PM_1−2.5, PM₁, and PM_0.25) were strongly and positively correlated with the Cr(VI) concentrations for PM_2.5. The study determined that approximately 56.14% of the hexavalent chromium inhaled during the spray-painting process was deposited in the upper respiratory system of the head airway region, followed by the alveolar and tracheobronchial regions, with fractions of 11.93 and 0.05%, respectively. Although the mean ratio of hexavalent chromium to total chromium was only 3.6% for all particle sizes, the cancer risk of the total particles in Cr(VI) (1.6 × 10⁻³) exceeded the acceptable risk value (10⁻⁶). The cancer risks of As and Cr(VI) associated with quasi-ultrafine particles, PM_0.5–1, PM_1–2.5, and PM_> 2.5, also exceeded 10⁻⁶. Comparison of the carcinogenicity risk of VOCs and metals suggests that the adverse health effect of inhaled particles on spray-painting workers is more serious than that from VOC exposure.