Pesticides in Latin American and Caribbean freshwater: a critical review

Pesticides used in food production can contaminate freshwater ecosystems. We present a critical analysis of pesticide use in Latin America and the Caribbean (LAC) from 1990 to 2020 and a systematic review of scientific literature about the presence of pesticides in freshwater, encompassing studies published from 1990 to 2023. Data were collected from FAOStat, PubMed, ScienceDirect, Scopus, and Google Scholar. Brazil was the primary pesticide user, with an annual consumption of 231 621 t, followed by Argentina (132 255 t) and Colombia (52 553 t). In 2020, LAC had the highest rate of pesticide application globally, with Ecuador leading at 13.74 kg/ha. South America dominates the total amount with 90.9% of pesticide use, primarily herbicides (51.5%), while pesticide usage in North and Central America, as well as the Caribbean, varied due to differing agricultural practices. The study examined 221 records for 26 out of 51 countries in the literature, highlighting the significant lack of information from numerous countries. Argentina, Mexico, and Brazil had the highest publication rates. Rivers, streams, and lakes (37%, 20%, and 12%, respectively) were the most studied systems, and research focused mainly on pesticide concentration in water (46%), sediments (27%), and aquatic biota (15%). The imbalance between pesticide usage and monitoring in freshwaters leads to concerns about the awareness of ecological risk. Therefore, the need for environmental monitoring in LAC is urgent to support the research to better understand pesticide impacts on these vital ecosystems.