Meng Xiaolan, Xu Fujun, Huang Yuanjia, Zhang Xing, Zhang Mantong
Xi 'an Academy of Environmental Protection Science, Xi'an 710061, China.
School of Water and Environment, Chang'an University, Xi'an 710054, China.
Heliyon. 2024 Aug 30;10(17):e37247. doi: 10.1016/j.heliyon.2024.e37247. eCollection 2024 Sep 15.
Land use types, land development and utilization intensity within watersheds have changed based on intensifying human activities and climate change, thereby inducing spatiotemporal variations in non-point source pollution (NPS), significantly impacting soil and water quality. This study performed a case study on an ecological environment functional zone at the northern foot of Qinling Mountains, an area strongly affected by human activities and land use changes. It employed an improved potential non-point pollution index (PNPI) model to analyze potential non-point source pollution (PNPS) and associated risk evolution characteristics in watershed over the past 30 years. The results indicate that from 1990 to 2020, the dominant land use categories were forest and arable land, making up 95 % of the entire watershed area. Notably, urban residential land presented the most significant expansion rates and nearly doubled in area between 1990 and 2020, whereas shrubland, grassland, and unused land showed a decreasing trend. With the application of the quantile classification method, PNPS risk values were divided into five categories: very low, low, moderate, high, and very high. A polarized trend in risk was observed, with increases in areas influenced by human activities and rapid expansion of very high-risk regions. Concurrently, the pollution risk in the upstream water source area decreased. In recent years, accelerated urbanization has been the main driver causing expansion of high PNPS risk regions. This study explores the spatial and temporal evolution of PNPS risk in the Heihe Basin by using an improved PNPI model. The improved model is more accurate in calculations and provides a better understanding of the distribution of PNPS, which is an important reference for watershed management and water resource governance.
随着人类活动的加剧和气候变化，流域内的土地利用类型、土地开发利用强度发生了变化，进而引发了非点源污染（NPS）的时空变化，对土壤和水质产生了重大影响。本研究以秦岭北麓生态环境功能区为例进行研究，该区域受人类活动和土地利用变化影响较大。采用改进的潜在非点源污染指数（PNPI）模型，分析了过去30年流域内潜在非点源污染（PNPS）及其风险演变特征。结果表明，1990年至2020年，流域内主要土地利用类型为林地和耕地，占流域总面积的95%。值得注意的是，城镇居住用地扩张速率最为显著，1990年至2020年面积 nearly doubled，而灌木林、草地和未利用地呈减少趋势。采用分位数分类法，将PNPS风险值分为极低、低、中、高、极高五类。风险呈现两极分化趋势，受人类活动影响的区域增加，极高风险区域迅速扩张。同时，上游水源区污染风险降低。近年来，城市化加速是导致PNPS高风险区域扩张的主要驱动因素。本研究利用改进的PNPI模型探讨了黑河流域PNPS风险的时空演变。改进后的模型计算更准确，能更好地了解PNPS的分布情况，为流域管理和水资源治理提供了重要参考。
