The objective of this study was to evaluate if the maximum values (MVs) for pesticides in surface freshwater included in CONAMA directive 357/2005 are safe for aquatic biota, comparing them with ecotoxicology data published in the literature. The terms “aquatic toxicity”, “chronic” “acute”, “LC₅₀”, “EC₅₀”, “NOEL”, “NOEC” and the name of each pesticide were used for searches on the research platforms. Data from 534 tests reported in 37 published articles and three ecotoxicological databases were included in this study; 24% of the tests were carried out with producer organisms, 34% with primary consumers and 42% with secondary consumers. Microcrustaceans of the Daphnia genus and the fishes Pimephales promelas and Oncorhynchus mykiss were the organisms most used. Atrazine, alachlor and metolachlor were the most investigated pesticides. Atrazine and alachlor are approved in Brazil, with atrazine ranking fourth among the most used pesticides in the country. The results indicated that of the 27 pesticides included in the standard directive, 16 have a risk quotient (RQ) higher than the level of concern for at least one ecotoxicological parameter and may not protect the aquatic biota. The insecticide malathion, used in various agricultural crops in Brazil, was the one that presented the highest RQs (3125 and 3,125,000 for freshwaters classified as 1/2 and 3, respectively), related to a LC₅₀ (96 h) of 0.000032 µg/L in Chironomus ramosus. The results indicate that CONAMA directive 357/2005 should be updated in line with the current use of pesticides in the country, and the MVs should be re-evaluated so that they do not represent toxicity for the aquatic biota.

The use of pesticides in agriculture can leave residues in the treated crops. Pesticides are also potential contaminants of ground and surface water, as reported in many countries. The development of efficient analytical methods to quantify pesticides in water samples is a challenge due to the low levels present. The objective of this work was to develop and validate a method for pesticide analysis in water using sample lyophilization followed by UHPLC–MS/MS and to determine pesticide levels in samples from a Brazilian hydrographic basin. In total, 77 compounds were included, of which 28 were considered only qualitatively. The method was applied to analyze 142 water samples collected during the dry and rainy seasons of 2021–2022, of which 90 were surface and 52 were groundwater samples. In total, 19 compounds were detected in the samples (≥LOD), mainly atrazine (72.5%), atrazine-2-hydroxy (50%), fipronil (18.3%), and pirimiphos-methyl (15.5%). Most compounds (17) were detected during the rainy season regardless of the environmental compartment. Twenty-five samples had quantified levels of the compounds (≥LOQ), of which 80% were collected during the dry season, and 58.3% were groundwater samples (up to 1.045 µg L⁻¹ of 2,4-D in an artesian well). The highest concentrations found in surface water were of atrazine-2-hydroxy (0.171 and 0.179 µg L⁻¹), levels that represent a potential risk to aquatic organisms (risk quotient of 1.1). This work provides an analytical method for determining pesticides in water that can be applied to other environmental pollutants. Although the levels found in the samples complied with Brazilian legislation, constant monitoring should be conducted in the region to guarantee safe levels of the pesticide in water.

Este estudo avaliou as respostas morfoanatômicas de Bowdichia virgilioides (Fabaceae) sob deriva de glifosato em um agroecossistema do Cerrado brasileiro. Duas coletas de folhas foram realizadas para dez indivíduos de duas áreas: área de borda (AB) e área controle (AC). Os sintomas visuais foram avaliados com índices de injúria foliar (IIF) e de severidade (IS), os anatômicos através da utilização de técnicas usuais de anatomia e os micromorfométricos por meio do software Anati Quanti. Cloroses e necroses foram encontradas. Os IIFs e ISs foram maiores para as folhas da AB e pode ser devido aos impactos que ocorrem na borda de manejo da área agrícola. Cloroplastos arredondados, plasmólise celular, hiperplasia, proliferação e colapso celular, sintomas similares aos encontrados em estudos de simulação de deriva de glifosato, foram notados. A espessura do parênquima paliçádico e, consequentemente, do mesofilo diferiram significativamente entre coletas, na AB, e entre os indivíduos da AC e da AB, na coleta de maio de 2017. Fatores como a maior incidência solar nas plantas de AB, provável ocorrência de outras pulverizações, assim como maior período de exposição e ação de contaminantes nas folhas da segunda coleta explicam essas alterações. Em campo, as avaliações visual, anatômica e morfométricas dos sintomas foliares foram sugestivas de deriva de agrotóxicos.