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据日本农用污染状况调查,,镉污染地水田占9.5%,一般旱土占3.2%,果园占7.5%。水田土壤被污染可采取客土法,在污染表面加厚20～30厘米的非污染土壤;也可以结合大量施用石灰、磷肥、硅肥或长期淹水使镉成为难溶状态。河水中镉的本底浓度在0.1ppb以下,如浓度稍高,土壤就能对它吸附。灌溉水质标准规定镉浓度为0.01ppm,在此以上土壤就会被污染。镉大部分是吸附在表层土1～2厘米深处。镉可以被粘土矿物、腐植质、铁铝氢氧化物等吸附,也可以成为Cds难溶物存在于土
According to the survey of agricultural pollution in Japan, cadmium contaminated paddy fields account for 9.5%, generally dry land accounts for 3.2%, orchards accounted for 7.5%. Soil polluted paddy soil can be taken by law, in the contaminated surface thickening of 20-30 cm of non-polluting soil; can also be combined with the large amount of lime, phosphate fertilizer, silicon fertilizer or long-term flooding make cadmium into a insoluble state. The background concentration of cadmium in rivers is below 0.1ppb, and at a slightly higher concentration, the soil can adsorb it. Irrigation water quality standards cadmium concentration of 0.01ppm, above which the soil will be contaminated. Most cadmium is adsorbed on the surface soil 1 ~ 2 cm deep. Cadmium can be clay minerals, humus, iron and aluminum hydroxide adsorption, can also be difficult to dissolve Cds exist in the soil