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

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.

Automated summary

This study provides insights into the research status and hot issues concerning NPS pollution from 2012 to 2021 through bibliometric analysis. The results demonstrate the increasing attention on the migration and transformation mechanism of heavy metals and emerging pollutants, ecological risk assessment, accurate traceability techniques, sustainable control technologies, and marine pollution. Moreover, developing countries are expected to show a higher interest in NPS pollution research in the future, building upon the progress made by developed countries.