Roychowdhury Tarit, Uchino Tadashi, Tokunaga Hiroshi, Ando Masanori
Division of Environmental Chemistry and Exposure Assessment, National Institute of Health Sciences, Tokyo, Japan.
Chemosphere. 2002 Nov;49(6):605-18. doi: 10.1016/s0045-6535(02)00309-0.
Domkal is one of the 19, out of 26 blocks in Murshidabad district where groundwater contains arsenic above 0.05 mg/l. Many millions of cubic meters of groundwater along with arsenic and other heavy metals are coming out from both the hand tubewells, used by the villagers for their daily needs and shallow big diameter tubewells, installed for agricultural irrigation and depositing on soil throughout the year. So there is a possibility of soil contamination which can moreover affect the food chain, cultivated in this area. A somewhat detailed study was carried out, in both micro- and macrolevel, to get an idea about the magnitude of soil contamination in this area. The mean concentrations (mg/kg) of As (5.31), Fe (6740), Cu (18.3), Pb (10.4), Ni (18.8), Mn (342), Zn (44.3), Se (0.53), Mg (534), V (44.6), Cr (33.1), Cd (0.37), Sb (0.29) and Hg (0.54) in fallow land soils are within the normal range. The mean As (10.7), Fe (7860) and Mg (733) concentrations (mg/kg) are only in higher side whereas Hg (0.17 mg/kg) is in lower side in agricultural land soils, compared to the fallow land soils. Arsenic concentrations (11.5 and 28.0 mg/kg respectively) are high in those agricultural land soils where irrigated groundwater contains high arsenic (0.082 and 0.17 mg/l respectively). The total arsenic withdrawn and mean arsenic deposition per land by the 19 shallow tubewells per year are 43.9 kg (mean: 2.31 kg, range: 0.53-5.88 kg) and 8.04 kg ha(-1) (range: 1.66-16.8 kg ha(-1)) respectively. For the macrolevel study, soil arsenic concentration decreases with increase of distance from the source and higher the water arsenic concentration, higher the soil arsenic at any distance. A proper watershed management is urgently required to save the contamination.
多姆卡尔是默希达巴德区26个街区中的19个之一，这里的地下水中砷含量超过0.05毫克/升。数百万立方米含有砷和其他重金属的地下水从村民用于日常需求的手压管井以及为农业灌溉而安装的浅大口径管井中涌出，并全年沉积在土壤中。因此存在土壤污染的可能性，进而可能影响该地区种植的食物链。为了了解该地区土壤污染的程度，在微观和宏观层面都进行了较为详细的研究。休耕土地土壤中砷（5.31）、铁（6740）、铜（18.3）、铅（10.4）、镍（18.8）、锰（342）、锌（44.3）、硒（0.53）、镁（534）、钒（44.6）、铬（33.1）、镉（0.37）、锑（0.29）和汞（0.54）的平均浓度（毫克/千克）在正常范围内。与休耕土地土壤相比，农业用地土壤中砷（10.7）、铁（7860）和镁（733）的平均浓度（毫克/千克）仅偏高，而汞（0.17毫克/千克）偏低。在灌溉地下水砷含量较高（分别为0.082毫克/升和0.17毫克/升）的那些农业用地土壤中，砷浓度（分别为11.5毫克/千克和28.0毫克/千克）较高。19口浅管井每年抽取的总砷量和每公顷土地的平均砷沉积量分别为43.9千克（平均：2.31千克，范围：0.53 - 5.88千克）和8.04千克/公顷（范围：1.66 - 16.8千克/公顷）。对于宏观层面的研究，土壤砷浓度随着与污染源距离的增加而降低，并且在任何距离处，水中砷浓度越高，土壤砷含量越高。迫切需要进行适当的流域管理以防止污染。
