Integrating multi-pathway risk evaluation of arsenic-contaminated soils and the intervention strategies for children

An accurate evaluation of human health risks from exposure to contaminated soils depends on several factors, including an accurate estimation of the site-specific bioavailability of metals. This study aimed to evaluate the risks associated with exposure to arsenic (As) contaminated soils through ingestion, inhalation, and dermal contact pathways in children under six years old. Additionally, relative bioavailability (RBA) and in vitro bioaccessibility (IVBA) were considered in the ingestion risk calculation, while local inhalation rates (IR) were used for estimating inhalation risk. Forty-one soil samples were collected in this study. Arsenic RBA was determined using a mouse urinary excretion bioassay. Two IVBA methods-EPA Method 1340 and the physiologically based extraction test (PBET)-were evaluated against the RBA values. The RBA of As ranged from 15.4% to 21.8% at Guandu (GD) sites. IVBA values using EPA Method 1340 ranged from 12.0% to 33.1%, while PBET values ranged from 4.3% to 13.0% for the gastric phase (GP) and 5.2% to 12.0% for the intestinal phase (IP). The hazard quotients (HQs) for the soil ingestion pathway in children aged 0-3 and 3-6 years old were below 1 when incorporating RBA and IVBA values. This study demonstrates that site-specific bioavailability assessments provide more accurate risk estimates than total metal concentrations, and that implementing simple hygiene interventions such as frequent handwashing can effectively reduce cumulative health risks from multiple exposure pathways in contaminated soil environments.