The global progress on the non-point source pollution research from 2012 to 2021: a bibliometric analysis

Abstract

Background With effective control of point source pollution, non-point source (NPS) pollution has been widely concerned as the primary reason for the improvement of global water environmental quality. Some bibliometric analysis related to NPS pollution has been carried out before the mid-2010s. Analyzing the research status and hot issues of NPS pollution in the past decade is important for guiding the control and management of NPS pollution in the future. Results A bibliometric analysis was conducted based on 3407 publications retrieved from the Web of Science during 2012–2021. China, USA and UK were the most productive countries. Sci. Total Environ, Environ. Sci. Pollut. Res, and Water were the most productive journals. The NPS pollutant, pollution types, driving forces, technology and the research object were retrieved from the keywords analysis. The common NPS pollutants of nitrogen, phosphorus, and heavy metals grabbed the highest attention, while the emerging contaminants have attracted increased attention. The migration and transformation of agricultural NPS pollution and urban NPS pollution driven by climate change and land use change were hot issues related to NPS pollution studies. Technologies related to the combination of 3S technology (RS, GIS, and GPS) and NPS pollution models, the sustainable control technologies, the technology of accurate traceability and automatic monitoring, and the comprehensive management plan were the important research areas related to NPS pollution. Although the research locations were mostly concentrated in the surface water and groundwater, the ocean and drinking water have great potential for future research. Conclusions This study illustrates the global focuses related to NPS pollution during 2012–2021 according to analyzing the publication outputs, source journals, source country, author, institution and the high-frequency keywords. Results demonstrated that the migration and transformation mechanism and ecological risk assessment for heavy metals and emerging pollutants, accurate traceability techniques, sustainable ecological restoration control techniques, and marine pollution have attracted rising attention. Additionally, developing countries will have a higher interest in NPS pollution in the future, because developed countries have already made great progress in controlling NPS pollution.

Investigating Nonpoint Source and Pollutant Reduction Effects under Future Climate Scenarios: A SWAT-Based Study in a Highland Agricultural Watershed in Korea

“…Agricultural nonpoint source (NPS) pollution is a global issue that is primarily generated by local agricultural activities [1,2]. According to data, NPS contamination has harmed 30-50% of surface water sources, making it an increasingly serious threat to water quality and aquatic ecosystem restoration [3].…”

Evaluation of agricultural non-point source pollution using an in-situ and automated photochemical flow analysis system

“…The average nitrogen utilization has been found to exceed the internationally recommended safe threshold resulting in the occurrence of cluster, explosion, and crossover ANPS pollution 14 . Moreover, it has been observed in several other developed nations that ANPS pollution has emerged as a significant contributor to water pollution 15 . Additionally, ANPS pollution from agricultural lands, such as nutrients, sediment, and agricultural chemicals, can originate from multiple locations, making it difficult to implement centralized control measures 16 .…”

Groundwater quality assessment and human health risks in Ovitoto, Otjozondjupa Region, Namibia

“…Due to a lack of access to modern machinery for the installation of boreholes with an average geological depth of between 100 and 150 m that can supply relatively cleaner and more potable water, rural community members usually use manual and less effective tools in creating and accessing groundwater commonly referred to as "wells" with depth varying between 6 and 9 m depending on groundwater level. Notwithstanding the depth of the groundwater source, the quality of water therefrom can become degraded as a result of pollution from point and non-point sources (UNEP, 2010; Daly et al, 2021;Ye et al, 2022).…”