State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an, 710048, China.
State Key Laboratory of Water Resources & Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China.
Environ Sci Pollut Res Int. 2021 Dec;28(45):64322-64336. doi: 10.1007/s11356-021-15603-w. Epub 2021 Jul 24.
Non-point source (NPS) pollution has become a vital contaminant source affecting the water environment because of its wide distribution, hydrodynamic complexity, and difficulty in prevention and control. In this study, the identification and evaluation of NPS pollution risk based on landscape pattern were carried out in the Hanjiang River basin above Ankang hydrological section, Shaanxi province, China. Landscape distribution information was obtained through land use data, analyzing the contribution of "source-sink" landscape to NPS pollution through the location-weighted landscape contrast index. Using the NPS pollution risk index to identify and evaluate the regional NPS pollution risk considering the slope, cost distance, soil erosion, and precipitation erosion affect migration of pollutants. The results showed that (i) the pollution risk was generally high in the whole watershed, and the sub-watersheds dominated by "source" landscapes account for 74.61% of the whole basin; (ii) the high-risk areas were distributed in the central, eastern, and western regions of the river basin; the extremely high-risk areas accounted for 12.7% of the whole watershed; and the southern and northern regions were dominated by forestland and grassland with little pollution risk; (iii) "source" landscapes were mostly distributed in areas close to the river course, which had a great impact on environment, and the landscape pattern units near the water body needed to be further adjusted to reduce the influence of NPS pollution.
非点源（NPS）污染因其分布广泛、水动力复杂以及难以预防和控制，已成为影响水环境的重要污染物来源。本研究基于景观格局，对陕西省安康水文断面以上的汉江水系进行了非点源污染风险识别与评价。通过土地利用数据获取景观分布信息，通过位置加权景观对比指数分析“源-汇”景观对 NPS 污染的贡献。利用 NPS 污染风险指数，考虑坡度、成本距离、土壤侵蚀和降水侵蚀对污染物迁移的影响，对区域 NPS 污染风险进行识别和评价。结果表明：（i）整个流域的污染风险普遍较高，以“源”景观为主的子流域占整个流域的 74.61%；（ii）高风险区分布在流域的中、东部和西部；极高风险区占整个流域的 12.7%；而南部和北部地区则以林地和草地为主，污染风险较小；（iii）“源”景观主要分布在靠近河道的区域，对环境影响较大，需要进一步调整水体附近的景观格局单元，以减少 NPS 污染的影响。
