Assessment of the health risk related to exposure to ultrafine, fine, and total particulates and metals in a metal finishing plant

The materials and byproducts of the processes used in the metal finishing industry are released as particle contaminants into the air in the workplace. The present study aimed to determine the concentrations and size distributions of these particles and of elements chromium, nickel, copper, manganese, cobalt, and lead (Cr, Ni, Cu, Mn, Co, and Pb, respectively) in a metal finishing industry and evaluate their potential health risks. Particles that are airborne from the dipping baths in the plant were sampled using a Sioutas cascade impactor at five different size fractions (PM>₂.₅, PM₁.₀–₂.₅, PM₀.₅–₁.₀, PM₀.₂₅–₀.₅, PM<₀.₂₅) and gravimetric analyses were conducted on the sampled filters. The GF-AAS 600 graphite atomic absorption spectrophotometer (PerkinElmer Corporation, Waltham, MA, USA) was used to analyze the elements and the method of USEPA was used to assess the health risk. The ratio of fine particles (PM₂.₅) to total suspended particles (TSPs) was 0.6. We observed that 50% of TSPs were composed of PM₁.₀ and that 68–88% of the metals were found in the fine particle fractions. Pb, Cr, and Mn were significantly positively correlated in the PM₁.₀ fraction, and the highest linear relationship was found between Pb and Cr (r = 0.85, p < 0.01). The total hazard quotient (HQ) for PM₂.₅ was 1.43, which is higher than the acceptable limit of 1.0. The excess lifetime cancer risk (ELCR) for hexavalent chromium (Cr[VI]) in PM₂.₅ was 6.09 × 10⁻⁵ for female workers and 6.54 × 10⁻⁵ for male workers, which are higher than the acceptable limit of 1.0 × 10⁻⁶, while total ELCRs for female and male workers were 6.21 × 10⁻⁵ and 6.21 × 10⁻⁵, respectively. The lifetime cancer risk associated with Cr(VI) in Cr electroplating plants should be taken into consideration as a significant health risk for the workers.