Urinary inorganic arsenic in residents living in close proximity to a nickel and copper smelter in Ontario, Canada.

OBJECTIVES The current study determines whether internal exposure to inorganic arsenic for residents living in close proximity to an operating smelter is any different from that for residents living in a similar community without anthropogenic sources of inorganic arsenic. Furthermore, the study examines factors that may contribute to internal inorganic arsenic exposure in these populations. METHODS A cross-sectional study was used to determine whether recent internal exposure to inorganic arsenic for residents living in close proximity to an operating smelter with known elevated soil arsenic content is any different from exposure for residents living in a similar socio-demographic community without point sources of arsenic. Personal information was collected from participants during in-home interviews, and first morning void urine samples were obtained to assess recent internal exposure to arsenic. RESULTS The mean concentration of urinary inorganic arsenic of residents living in the exposed community was 7.11 ug/L (Standard deviation (SD) 4.53, N = 368) and in the non-exposed community was 7.19 ug/L (SD 5.63, N = 321). The difference in urinary inorganic concentration was not statistically significant (p = 0.83). Regression analysis showed that age and sex were significant predictors of internal exposure, with males and younger age groups having higher exposure levels. CONCLUSIONS Based on analyses of data collected, the results did not demonstrate a statistically significant difference in recent internal exposure to inorganic arsenic between the community with and the one without industrial or other point sources of environmental arsenic contamination. However, individual characteristics such as age and sex are important contributors to urinary inorganic arsenic levels.