Chaudri A M, Allain C M, Badawy S H, Adams M L, McGrath S P, Chambers B J
Agriculture and Environment Division, IACR-Rothamsted, Harpenden, Herts, UK.
J Environ Qual. 2001 Sep-Oct;30(5):1575-80. doi: 10.2134/jeq2001.3051575x.
Grain Cd concentrations were determined in the wheat (Triticum aestivum L.) cultivars Soissons, Brigadier, and Hereward grown in 1994,1996, and 1999, respectively, in soils of a long-term field experiment to which sewage sludges contaminated with Zn, Cu, Ni, or Cr had previously been added. Soil pore water soluble Cd and free Cd2+ increased linearly with increasing total soil Cd (R2=0.82 and 0.84, respectively; P<0.001). Similarly, soil pore water free Cd2+ increased linearly with increasing soil pore water soluble Cd (R2=0.98; P<0.001). There was no evidence of a plateau in soil pore water Cd concentrations with increasing soil Cd concentrations. Grain Cd concentrations were significantly correlated with total soil Cd (P<0.001), soil pore water Cd (P<0.001), and free Cd2+ (P<0.001). A slight curvilinear relationship between grain Cd and soil Cd was apparent, but there was no plateau, even at the maximum soil Cd concentration of about 2.7 mg kg(-1). The relationship between soil pore water Cd and grain Cd was linear for all three cultivars. The slopes were in the order 1994 > 1996 > 1999, with more Cd being taken up into the grain by Soissons grown in 1994, and least by Hereward grown in 1999. For Soissons, Cd concentration in the grain greater than the EU limit (0.24 mg kg(-1) dry wt.) occurred at soil Cd less than the current UK limit of 3 mg kg(-1) for soils receiving sewage sludge. In contrast, for Brigadier and Hereward, grain Cd concentrations were near to and less than the EU limit, respectively, at soil Cd concentrations of 3 mg kg(-1).
在长期田间试验的土壤中，分别于1994年、1996年和1999年种植了小麦品种苏瓦松、准将和赫里沃德，测定了其籽粒中的镉浓度。此前已向这些土壤中添加了被锌、铜、镍或铬污染的污水污泥。土壤孔隙水中的可溶性镉和游离镉离子随土壤总镉含量的增加呈线性增加（R2分别为0.82和0.84；P<0.001）。同样，土壤孔隙水中的游离镉离子随土壤孔隙水中可溶性镉的增加呈线性增加（R2=0.98；P<0.001）。没有证据表明随着土壤镉浓度的增加，土壤孔隙水中的镉浓度会出现平稳状态。籽粒镉浓度与土壤总镉（P<0.001）、土壤孔隙水镉（P<0.001）和游离镉离子（P<0.001）显著相关。籽粒镉与土壤镉之间存在轻微的曲线关系，但即使在土壤镉最高浓度约为2.7 mg kg(-1)时也没有平稳状态。对于所有三个品种，土壤孔隙水镉与籽粒镉之间的关系都是线性的。斜率顺序为1994年>1996年>1999年，1994年种植的苏瓦松吸收到籽粒中的镉最多，1999年种植的赫里沃德吸收到籽粒中的镉最少。对于苏瓦松，当土壤镉含量低于英国目前对接收污水污泥土壤规定的3 mg kg(-1)限值时，籽粒中的镉浓度就超过了欧盟限值（0.24 mg kg(-1)干重）。相比之下，对于准将和赫里沃德，在土壤镉浓度为3 mg kg(-1)时，籽粒镉浓度分别接近和低于欧盟限值。
