Biological monitoring and the influence of genetic polymorphism of As3MT and GSTs on distribution of urinary arsenic species in occupational exposure workers

PURPOSE: To examine the differences in urinary arsenic metabolism patterns in men affected by occupational exposure, we performed a study on 149 participants—workers of a copper mill and 52 healthy controls without occupational exposure. To elucidate the role of genetic factors in arsenic (As) metabolism, we studied the associations of six polymorphisms: As3MT Met287Thr (T>C) in exon 9; As3MT A>G in 5′UTR; As3MT C>G in intron 6; As3MT T>G in intron 1; GSTP1 Ile105Val and GSTO2 T>C. METHODS: Air samples were collected using individual samplers during work shift. Urine samples were analyzed for total arsenic and arsenic chemical forms (As(III); As(V), MMA, DMA, AsB) using HPLC–ICP-MS. A specific polymerase chain reaction was done for the amplification of exons and flanking regions of As3MT and GSTs. RESULTS: The geometric mean arsenic concentrations in the air were 27.6 ± 4.9 µg/m(3). A significant correlation (p < 0.05) was observed between arsenic in air and sum of iAs +MMA and iAs. As3MT (rs3740400) GG homozygotes showed significantly (p < 0.05) higher %iAs (21.8 ± 2.0) in urine than GC+CC heterozygotes (16.0 ± 2.1). A strong association between the gene variants and As species in urine was observed for GSTO2 (rs156697) polymorphism. CONCLUSIONS: The findings of the study point out that the concentration of iAs or the sum of iAs + MMA in urine can be a reliable biological indicator of occupational exposure to arsenic. This study demonstrates that As3MT and/or GSTs genotype may influence As metabolism. Nevertheless, further studies investigating genetic polymorphism in occupational conditions are required.