MOE Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
MOE Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
Chemosphere. 2023 Sep;335:139148. doi: 10.1016/j.chemosphere.2023.139148. Epub 2023 Jun 6.
The quality of farmland soils on the Tibetan Plateau is important because of the region's ecological vulnerability and their close link with local food security. Investigation on the pollution status of heavy metal (loid)s (HMs) in the farmlands of Lhasa and Nyingchi on the Tibetan Plateau, China revealed that Cu, As, Cd, Tl, and Pb were apparently enriched, with the soil parent materials being the primary sources of the soil HMs. Overall, the farmlands in Lhasa had higher contents of HMs compared to those in Nyingchi, which could be attributed to the fact that the former were mainly developed on river terraces while the latter were mainly developed on the alluvial fans in mountainous areas. As displayed the most apparent enrichment, with the average contents in the vegetable field soils and grain field soils of Lhasa being 2.5 and 2.2 times higher compared to those of Nyingchi. The soils of vegetable fields were more heavily polluted than those of grain fields, probably due to the more intensive input of agrochemicals, particularly the use of commercial organic fertilizers. The overall ecological risk of the HMs in the Tibetan farmlands was low, while Cd posed medium ecological risk. Results of health risk assessment show that ingestion of the vegetable field soils could pose elevated health risk, with children facing greater risk than adults. Among all the HMs targeted, Cd had relatively high bioavailability of up to 36.2% and 24.9% in the vegetable field soils of Lhasa and Nyingchi, respectively. Cd also showed the most significant ecological and human health risk. Thus, attention should be paid to minimize further anthropogenic input of Cd to the farmland soils on the Tibetan Plateau.
青藏高原农田土壤质量很重要，因为该地区生态脆弱，与当地粮食安全密切相关。对中国拉萨和林芝地区农田重金属（类金属）污染状况的调查表明，Cu、As、Cd、Tl 和 Pb 明显富集，土壤母质是土壤重金属的主要来源。总体而言，拉萨农田的重金属含量高于林芝，这可能是因为前者主要发育在河流阶地上，而后者主要发育在山区的冲积扇上。As 表现出最明显的富集，拉萨蔬菜地和粮食地土壤中 As 的平均含量分别比林芝高 2.5 倍和 2.2 倍。蔬菜地土壤比粮食地土壤污染更严重，这可能是由于农业化学品投入更密集，特别是商业有机肥的使用。青藏高原农田重金属的整体生态风险较低，而 Cd 则构成中等生态风险。健康风险评估的结果表明，摄入蔬菜地土壤可能会造成更高的健康风险，儿童比成人面临更大的风险。在所研究的重金属中，Cd 的生物有效性相对较高，拉萨和林芝蔬菜地土壤中的 Cd 生物有效性分别高达 36.2%和 24.9%。Cd 还表现出最显著的生态和人类健康风险。因此，应注意尽量减少人为向青藏高原农田土壤中进一步输入 Cd。
