Evaluation on bioaccessibility of arsenic in the arsenic-contaminated soil

Korea Ministry of Environment regulates the soil quality based on the pseudo-total content of metals extracted by aqua-regia, and the concentration of metals has been used in the risk assessment of the contaminated site. The pseudo-total content of metals can be accepted conservatively as a potentially risky concentration of metals in the soil. However, only some portion of metals in the soil are absorbed by plants, animals, and human beings, and the pseudo-total content used in the risk assessment tend to overestimate the risk of metal contamination. Therefore, the pseudo-total content does not reflect the real risk of the contamination. Bioavailability and bioaccessibility can be alternatives for the pseudo-total content to estimate the reasonable risk. Bioaccessible concentration can be analyzed as in-vitro by the amounts of metals extracted in the gastrointestinal situation, and the bioaccessible concentration is the maximum amount of metals to be absorbed. The bioaccessible concentration of As was evaluated, compared with the pseudo-total concentration of As, and the correlation between the concentration of As and physicochemical properties of soil was analyzed. The bioaccessible concentration can be estimated by the labile fractions of As, and Si, Al, and Mn content decrease the bioaccessible concentration of As.