Glyphosate and Aminomethylphosphonic Acid: A Map of the Bibliography on Ecotoxicology, Fate, and Monitoring Frontier Studies in Environmental Research

Glyphosate is one of the most widely used herbicides worldwide, and its extensive application has raised increasing concern regarding environmental occurrence, ecological exposure, and potential risks to non-target organisms. Its major degradation product, aminomethylphosphonic acid (AMPA), has also received growing attention because of its persistence, transport behavior, and contribution to long-term contamination profiles. To clarify the development and emerging priorities of this field, we conducted a bibliometric review of glyphosate-related publications indexed in the Web of Science Core Collection from 1974 to 2024. After screening and data cleaning, 7050 articles and reviews were included. Publication output increased markedly over time, with annual publications exceeding 300 after 2019 and reaching a peak of 488 in 2023. The United States ranked first with 1928 publications, accounting for 27.4% of the total output, followed by Brazil and China. Keyword co-occurrence, temporal overlay, and collaboration analyses showed that glyphosate research has shifted from early agronomic topics, including herbicide efficacy, crop selectivity, and resistance management, toward a broader environmental research framework. Three major research fronts were identified: mechanism-oriented ecotoxicology in non-target organisms, environmental fate and transport of glyphosate and AMPA across soil–water–sediment systems, and the development of analytical and sensing technologies for environmental monitoring. The results further indicate that the field is moving from single-compound residue assessment toward integrated contaminant-ecology perspectives linking occurrence, transformation, biological response, exposure assessment, and ecological risk. Future studies should strengthen the integration of long-term environmental monitoring, AMPA-inclusive risk assessment, realistic multi-stressor exposure scenarios, and field-deployable detection technologies. This review provides a quantitative overview of the global research landscape and identifies priority directions for environmental assessment and management of glyphosate and AMPA contamination.