2019 年 42 巻 p. 31-39
Heavy metal (Cr, Cu, Zn, As, Cd, and Pb) contamination in soil was examined in a multi-industry district of Bangladesh in the dry and wet season. In this district, various kinds of industries discharged their wastewater into nearby irrigation canals, and soil contaminated with this water could be a major environmental pollution factor. The geoaccumulation index (Igeo) indicated that the study areas (in both dry and wet season) were treated as uncontaminated to moderately contaminated with Zn and As in Banglabazar; Zn, Cu, and As in Kashimpur; and Zn in Chandra but uncontaminated with other heavy metals. The pollution load index (PLI) showed the study areas were slightly contaminated in the dry season whereas uncontaminated in the wet season. Based on potential ecological risk index (RI) only Banglabazar area posed moderate risk in the dry season whereas other areas posed low risk in the both seasons. On the other hand, the characteristics of lower Igeo, PLI and RI values in the wet season showing the dilution effect of rainfall (in irrigation water) on the soil’s low absorption of the heavy metals. The results of current study clearly pointed out that the study areas were mostly uncontaminated with heavy metals and pose low risk to the environment.
