Copper Pollution in Agricultural Soils: A Bibliometric Analysis and PRISMA-Guided Systematic Review of Sources, Environmental Impacts, and Remediation

Copper (Cu) accumulation in agricultural soils, resulting from various anthropogenic inputs, can adversely affect soil properties, crop productivity, and environmental quality. Effective monitoring and sustainable remediation are therefore important for managing contaminated soils. This review combines systematic bibliometric analysis with qualitative thematic synthesis to examine research on Cu pollution in agricultural soils. The literature was retrieved from Scopus and Web of Science and screened according to the PRISMA guidelines. Following duplicate removal and eligibility assessment, the final dataset comprised 726 publications covering the period 1988–2025. Bibliometric and thematic analyses were used to identify publication trends and seven major research areas addressing Cu sources and occurrence, analytical methods, environmental and biological effects, co-contamination, and remediation. The bibliometric results revealed a geographically diverse research field dominated by environmental and agricultural sciences, with prominent themes including Cu contamination, metal interactions, ecological effects, crop uptake, and remediation. The qualitative synthesis indicates that Cu accumulation can alter soil microbial communities and nutrient cycling and impair crop growth, although the magnitude of these effects depends on soil conditions, Cu availability, and exposure levels. Immobilisation, biochar, phytoremediation, microbial-assisted approaches, and advanced monitoring technologies have shown potential for managing Cu-contaminated soils. Their effectiveness depends on site conditions and the endpoints used to assess remediation. Sustainable management requires source-specific monitoring, appropriate environmental and exposure-risk assessment, and integrated remediation strategies supported by long-term field research.