Atmospheric levels and cytotoxicity of PAHs and heavy metals in TSP and PM 2.5 at an electronic waste recycling site in southeast China

Abstract

Twenty-nine air samples of total suspended particles (TSP, particles less than 30–60 μm) and thirty samples of particles with aerodynamic diameter smaller than 2.5 μm (PM 2.5) were collected at Guiyu, an electronic waste (e-waste) recycling site in southeast China from 16 August 2004 to 17 September 2004. The results showed that mass concentrations contained in TSP and PM 2.5 were 124±44.1 and 62.12±20.5 μg m −3, respectively. The total sum of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) associated with TSP and PM 2.5 ranged from 40.0 to 347 and 22.7 to 263 ng m −3, respectively. Five-ring and six-ring PAHs accounted for 73% of total PAHs. The average concentration of benzo(a) pyrene was 2–6 times higher than in other Asian cities. Concentrations of Cr, Cu and Zn in PM 2.5 of Guiyu were 4–33 times higher than in other Asian countries. In general, there were significant correlations between concentrations of individual contaminants in TSP with PM 2.5 (i.e. PAHs, Cd, Cr, Cu, Pb, Zn, Mn except Ni and As). The high concentrations of both PAHs and heavy metals in air of Guiyu may impose a serious environmental and health concern. Cytotoxicity of the extract of TSP and PM 2.5 of ten 24 h samples collected against human promonocytic leukemia cell line U937 (ATCC 1593.2) was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxicity assay. The results showed that under the same concentrations of extract, PM 2.5 cytotoxicity was 2–4 times higher than TSP.