Soluble arsenic species in total suspended particles and their health risk and origin implication: A case study in Taiyuan, China

Abstract

The inhalation is one of important exposure ways to arsenic. Traditionally, the health risk of arsenic exposure from particulate matter (PM) was assessed by using total arsenic, which may erroneously estimate the health risk of arsenic since the toxicity of arsenic depends on its chemical species and not all arsenic in PM is bio-accessible. Herein, total suspended particles (TSP) were collected from Taiyuan in China during whole year of 2018, and the species and concentrations of arsenic in TSP were investigated in order to more accurately assess the health risk of arsenic exposure from TSP and evaluate the possible sources of arsenic in TSP. Total arsenic varied within 1.16–28.4 ng/m3 with a mean value of 7.40 ng/m3, which exceeded the standard limit of China (6 ng/m3). Two arsenic species, As5+ and As3+, were detected out in soluble fractions of TSP, with As5+ as dominant species. Total arsenic, soluble arsenic and soluble As5+ in TSP revealed closed correlation each other, indicating that they may originate from similar anthropogenic and crust sources. Soluble As3+ showed no obvious correlations with total arsenic, implying that soluble As3+ has different dominant sources. The ratio of As5+/As3+ significantly varied within 1.08–32.5 and the percentages of soluble arsenic in total arsenic varied within 50%–93%, implying that arsenic in TSP of Taiyuan has multiple sources and none of them stably dominated during 2018. Non-carcinogenic risk and carcinogenic risk indicators calculated with soluble arsenic species showed significant difference to that calculated with total arsenic or soluble arsenic when TSP contained equivalent As5+ and As3+, verifying that it is necessary and more accurate to assess the health risk of arsenic exposure from TSP by using soluble arsenic species, rather than total arsenic or soluble arsenic.