Distribution coefficients of tin in Japanese agricultural soils and the factors affecting tin sorption behavior

Sorption behavior of tin (Sn) in Japanese agricultural soils was studied. Soil–soil solution distribution coefficient ( K d) of Sn ( K d-Sn) for 142 soil samples ranged between 128 and 1 590 000 L kg −1 with the geometric mean of 12 400 L kg −1. The K d-Sn values for Andosol tended to be higher than those of the other soil groups. Among the relationships between K d-Sn values and soil properties, a high correlation was observed for soil active-Al (Al-(hydr)oxide and Al–humus complex) amount and K d-Sn. The pH effect on Sn sorption was also investigated. The results suggested that the low pH condition enhanced the Sn sorption in soils. The soil-sorbed Sn fractions in each type of soil material were also evaluated with selective extraction methods. The results showed that most of the soil-sorbed Sn was as organic matter bound or Al/Fe-(hydr)oxide-bound forms.