Department of Plant and Soil Sciences, University of Delaware, Newark, DE 19716, United States.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, CAS, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2018 Dec 10;644:624-634. doi: 10.1016/j.scitotenv.2018.06.230. Epub 2018 Jul 11.
The cruciferous crop, oil rapeseed (Brassica napus L.), may bioaccumulate excessive cadmium (Cd) and lead (Pb) as well, from Cd-enriched noncalcareous soils in Guizhou province of southwestern China. Field paired soil-rapeseed sampling and greenhouse experiment were performed to characterize the Cd anomaly in rapeseed-planting soils and to predict the bioaccumulation of Cd and Pb in raw seeds using soil variables. The results indicated that total soil-Cd concentrations averaged 0.43 mg kg (range 0.11-1.41 mg kg) from field investigation; and a soil type dependent Cd anomaly was observed. Besides, cumulative frequency of total soil-Cd was plotted to be helpful in delimitation of regional Cd anomalies. Rapeseeds readily bioaccumulated Cd from soils as validated by greenhouse experiment and field data. Contrary results were observed in relation to rapeseed Pb levels measured from greenhouse experiment (very low) and field (very high) which was likely due to soil particle contamination as indicated by the considerably higher ratio of Pb to Cd level in seeds harvested from fields. Based on multiple stepwise regression analysis, reliable Cd soil-rapeseed relationships, but less reliable for Pb, were derived using either total or (bio)available metal concentrations and were further inversely used to derive local soil Cd criteria (e.g., total soil-Cd based, 2.5 mg kg) based on Hygienic Standard for Feeds (GB13082-2001). Although seed Cd levels (<feed standard) observed in field data indicated a least human dietary risk, however, high (bio)availability of Cd, but not Pb, in Cd-enriched acid soil still poses high environmental risks and may threaten food safety of other crops.
十字花科作物油菜（Brassica napus L.）也可能从中国西南部贵州省富含镉（Cd）的非钙质土壤中过度积累镉（Cd）和铅（Pb）。进行了田间配对土壤-油菜采样和温室实验，以表征油菜种植土壤中的 Cd 异常，并使用土壤变量预测 Cd 和 Pb 在生种子中的生物累积。结果表明，从野外调查中得出，土壤总 Cd 浓度平均为 0.43mg/kg（范围为 0.11-1.41mg/kg）；并且观察到土壤类型依赖性 Cd 异常。此外，总土壤-Cd 的累积频率有助于划定区域 Cd 异常。温室实验和田间数据验证了油菜从土壤中易吸收 Cd。与温室实验（非常低）和田间（非常高）测量的油菜 Pb 水平观察到相反的结果，这可能是由于土壤颗粒污染所致，这是由于从田间收获的种子中 Pb 与 Cd 水平的比值明显较高所表明的。基于多元逐步回归分析，使用总金属或（生物）有效金属浓度可以得出可靠的 Cd 土壤-油菜关系，但对于 Pb 则不太可靠，并进一步反推出当地土壤 Cd 标准（例如，基于总土壤-Cd，2.5mg/kg）基于饲料卫生标准（GB13082-2001）。尽管田间数据中观察到的种子 Cd 水平（<饲料标准）表明人类饮食风险最小，但富 Cd 酸性土壤中 Cd 的高（生物）可利用性，但不是 Pb，仍然存在高环境风险，并可能威胁到其他作物的食品安全。
