This study presents an alternative method to the traditional reference dose approach for the determination of health risk-based soil standards for arsenic. The model combines multimedia equations for air, soil and dietary exposure, a toxicokinetic component, a probabilistic output, a reference distribution for urine arsenic in the general population and exposure parameters values traceable in US-EPA or EFSA reference studies. The model calculates a mean inorganic As urine concentration AsU (sum of inorganic arsenic Asi and its metabolites) from environmental data and exposure parameters, which is attributed to the central value of a lognormal distribution. Risk is assessed by comparing a high percentile of the modelled distribution to the target AsU attributed to the reference value of 10 µg/gCREA (microgram As per gram of creatinine), the upper confidence interval of the 95th percentile from the AsU distribution in the French population. A soil standard value of 40 mg/kg is determined as being the arsenic concentration in soil not giving rise to more than 5% probability of having a AsU concentration above the target value of 10 µg/gCREA. Once soil As concentrations above 40 mg/kg are measured, further environmental investigations should be carried, involving an assessment of As bioaccessibility to address health risks and decide of regulatory measures in residential setting.
Keywords: Chronic exposure; Multimedia model; Soil standards; Urinary speciated arsenic.
© 2021. The Author(s), under exclusive licence to Springer Nature B.V.