State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Environ Pollut. 2019 Dec;255(Pt 1):113184. doi: 10.1016/j.envpol.2019.113184. Epub 2019 Sep 10.
Assessing the ecological risk of combined pollution, especially from a holistic perspective with the consideration of the overarching functions of soil ecosystem, is crucial and beneficial to the improvement of ecological risk assessment (ERA) framework. In this study, four soils with similar physicochemical properties but contrasting heavy metals contamination levels were selected to explore changes in the integrated functional sensitivity (MSI), resistance (MRS) and resilience (MRL) of soil microbial communities subjected to herbicide siduron, based on which the ecological risk of the accumulation of siduron in the four studied soils were evaluated. The results suggested that the microbial biomass carbon, activity of denitrification enzyme and nitrogenase were indicative of MSI and MRS, and the same three parameters plus soil basal respiration were indicative of MRL. Significant dose-effect relationships between siduron residues in soils and MSI, MRS and MRL under combined pollution were observed. Heavy metal polluted soils showed higher sensitivity and lower resistance to the additional disturbance of herbicide siduron due to the lower microbial biomass, while the resilience of heavy metal polluted soils was much higher due to the pre-adaption to the chemical stresses. The quantifiable indicator microbial functional stability was incorporated in the framework of ERA and the results showed that the accumulation of siduron in the studied soils could exhibit potential harm to the integrated functional stability of soil microbial community. Thus, this work provides insights into the application of integrated function of soil microbial community into the framework of ERA.
评估复合污染的生态风险，特别是从整体角度考虑土壤生态系统的综合功能，对于改进生态风险评估（ERA）框架至关重要且有益。本研究选取了 4 种具有相似理化性质但重金属污染水平不同的土壤，旨在探讨除草剂噻磺隆作用下土壤微生物群落综合功能敏感性（MSI）、抗性（MRS）和恢复力（MRL）的变化，以此评估 4 种供试土壤中噻磺隆积累的生态风险。结果表明，微生物生物量碳、反硝化酶和氮酶活性可作为 MSI 和 MRS 的指示指标，而这三个相同的参数加上土壤基础呼吸可作为 MRL 的指示指标。在复合污染条件下，土壤中噻磺隆残留与 MSI、MRS 和 MRL 之间存在显著的剂量-效应关系。由于微生物生物量较低，重金属污染土壤对除草剂噻磺隆的额外干扰更为敏感且抗性较低，而重金属污染土壤的恢复力则更高，这是由于其对化学胁迫的预先适应。可量化的微生物功能稳定性指标被纳入 ERA 框架中，结果表明，供试土壤中噻磺隆的积累可能对土壤微生物群落的综合功能稳定性产生潜在危害。因此，本研究为将土壤微生物群落的综合功能应用于 ERA 框架提供了新的思路。
