State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Hebei Provincial Academy of Environmental Sciences, Shijiazhuang 050037, China.
Sci Total Environ. 2018 Jan 1;610-611:333-341. doi: 10.1016/j.scitotenv.2017.08.060. Epub 2017 Aug 11.
An increasing area of agricultural land is irrigated with wastewater worldwide due to the scarcity of fresh water resources. Whether wastewater irrigations can affect the electron transfer capacity (ETC) of natural organic matter in soils is unclear. In this study, we assess the responses of the electron-accepting capacity (EAC) and electron-donating capacity (EDC) of soil humic substances (HS) to irrigations with wastewaters from different sources. We show that the EAC of soil HS increases and the EDC of soil HS decreases after irrigation with domestic wastewater. Conversely, the EAC of soil HS decreases and the EDC of soil HS increases after irrigation with industrial wastewater. The EAC and EDC of soil HS exert no changes after irrigation with pharmaceutical wastewater. Irrigations with wastewaters from different sources can cause the distinct directions of changes in the activities of lignin peroxidase and laccase by altering the content of labile organic carbon, heavy metals or antibiotics in soils, thereby changing the chemical structures and finally the ETC of HS along different directions. These results can provide insights into the role of HS in environmentally relevant processes in agricultural soils under the context of wastewater irrigations.
由于淡水资源短缺，全球有越来越多的农业用地采用废水进行灌溉。废水灌溉是否会影响土壤中天然有机质的电子传递能力（ETC）尚不清楚。本研究评估了不同来源的废水中灌溉对土壤腐殖质（HS）的电子接受能力（EAC）和电子供体能力（EDC）的响应。结果表明，用生活污水灌溉后，土壤 HS 的 EAC 增加，EDC 降低。相反，用工业废水灌溉后，土壤 HS 的 EAC 降低，EDC 增加。用制药废水灌溉后，土壤 HS 的 EAC 和 EDC 没有变化。不同来源的废水灌溉通过改变土壤中易降解有机碳、重金属或抗生素的含量，导致木质素过氧化物酶和漆酶活性发生明显变化，从而改变 HS 的化学结构，最终沿不同方向改变 HS 的 ETC。这些结果可以深入了解在废水灌溉背景下 HS 在农业土壤中与环境相关过程中的作用。
