植物对关中地区城市污泥施用土壤中多氯联苯的吸收和传输特征
Plant Uptake and Translocation Characteristics of Polychlorinated Biphenyls in Soil Applied with Municipal Sludge in Guanzhong Area
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摘要: 城市污泥施用农田是污泥资源化处置的一种方式,能够改善土壤性状及促进作物生长,但也会使农田存在多氯联苯(polychlorinated biphenyls,PCBs)等污染物的暴露风险。作为一类持久性有机污染物,PCBs被吸收并累积在作物体内后,经食物链传递对人体健康构成潜在暴露风险。该研究基于不同污泥施用量、污泥类型和植物类型的土壤盆栽实验,以关中地区城市污泥为研究对象,探究作物对污泥施用土壤中PCBs的吸收和传输特征。结果表明:关中地区城市污泥施用造成土壤及植物PCBs污染,植物收获后,土壤、植物根和地上部分低氯代PCBs占比最高,且总百分含量呈依次增加趋势;土壤∑PCBs降解了20.00 %–79.30 %。植物根可以吸收土壤PCBs并向地上部分传输,且吸收和传输能力与污泥施用量、污泥类型和植物类型有关。施用加倍污泥量使植物根对∑PCBs、一–四氯代PCBs和六氯代PCBs的吸收减弱;韩城市龙门镇污泥(有机质含量最低)施用下植物根对∑PCBs的吸收能力最强。小麦对污染土壤∑PCBs及各PCBs同系物的吸收能力均强于玉米,而传输能力较弱。研究结论以期为污泥农用的风险评估、污泥施用土壤中PCBs的环境行为及PCBs污染土壤的植物修复提供科学依据。
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关键词:
- 污泥 /
- 土壤 /
- 多氯联苯(PCBs) /
- 吸收 /
- 传输
Abstract: The application of municipal sludge to farmland is a disposal method of sludge recycling, which can improve soil properties and promote crop growth, but also causes exposure risks of pollutants such as polychlorinated biphenyls (PCBs) in farmland. As a kind of persistent organic pollutants, PCBs are absorbed and accumulated in crops and bring potential exposure risks to human health through the food chain. Based on soil pot experiments with different sludge application quantity, sludge types, and plant types, the municipal sludge in Guanzhong area was taken as the research object to explore plant uptake and translocation characteristics of PCBs in soil applied with sludge. The results showed that: the application of municipal sludge in Guanzhong area led to PCBs pollution in soil and plant. After plant harvest, soil, plant roots, and above-ground parts were dominated by low-chlorinated PCBs with the total percent contents increased sequentially, and ∑PCBs in soil was degraded 20.00 %–79.30 %. Plant roots absorbed PCBs in soil and transmitted them to the above-ground part of plants. The uptake and translocation capacities of plants were related to sludge application quantity, sludge types, and plant types. Double sludge application quantity weakened the uptake of ∑PCBs, mono-PCBs–tetra-PCBs, and hexa-PCBs by plant roots. The uptake capacity of plant roots treated with the sludge of Longmen town, Hancheng city, China (sludge of the lowest organic matter content) to ∑PCBs was the highest. The uptake capacity of wheat to ∑PCBs and PCBs homologous in polluted soil was stronger than that of maize, while the translocation capacity was weak. The study provides scientific basis for the risk assessment of sludge agricultural application, the environmental behavior of PCBs in sludge application soil and the phytoremediation of PCBs contaminated soil.-
Key words:
- sludge /
- soil /
- polychlorinated biphenyls (PCBs) /
- uptake /
- translocation
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