Research Trends on Trace Element Contamination in Brazilian Urban Lentic Ecosystems: Environmental and Policy Drivers

Lentic ecosystems are vulnerable to contamination by trace elements, which can accumulate and pose risks to aquatic life and human health. In a large, developing country such as Brazil, marked by vast geographic, environmental, and socioeconomic diversity, it is crucial to understand how these factors shape research on this group of contaminants. Here, we conducted a systematic review of 65 studies published between 1980 and 2023 on Brazilian urban lentic systems, retrieved from Web of Science and Scopus databases. Research output increased sharply after 2011, with 73% of studies published in the last decade. Geographically, half of the studies were conducted in the Southeast region, especially in large urban areas within the Atlantic Forest biome, while the North and Central-West regions together accounted for less than 15%. Industrial zones were the most frequently studied land use, and sediment was the most common matrix. Copper, lead, chromium, zinc, and nickel were the most frequently reported trace elements, whereas toxic elements such as arsenic and mercury were infrequently studied. This review provides a quantitative synthesis of research on trace element contamination in Brazilian urban lentic ecosystems. The findings highlight critical gaps, including the underrepresentation of North and Central-West regions, the limited use of biological matrices, and the neglect of mercury and arsenic, despite their ecological and toxicological relevance. Addressing these gaps is essential to improve ecotoxicological risk assessments, strengthen the integration between environmental monitoring and public health, and guide evidence-based policies for pollution control in vulnerable aquatic systems.