Análise de multiresíduos de agrotóxicos e aspectos estruturais de poços de captação de águas subterrâneas utilizadas para o abastecimento público em comunidades rurais de municípios da Região das Missões/RS

Abstract

The water is a key resource for maintaining human basic needs so, for public supply, the water must have excellent quality and potability indexes. In rural middle, commonly used water collected from underground wells, no treatment, however, pesticide residues may be present in this resource, due to the intensive use of pesticides in these areas. Therefore, the objective of this study was to determine pesticide residues in groundwater used for public supply in rural middle in 13 municipalities of the Missions Region of the state of Rio Grande do Sul. The methodological procedure consisted of four collections in 2019 corresponding to the four seasons of the year in 13 underground wells in rural areas of 13 municipalities of the Missions Region/RS. Were monitored 24 pesticides: 2,4-D, atrazine, azoxystrobin, bentazone, carbofuran, cyproconazole, clomazone, difenoconazole, epoxiconazole, fipronil, imazapyr, imazethapyr, malathion, metsulfuron-methyl, penoxsulam, pyraclostrobin, pyrazosulfuronethyl, pirimicarb, profenofos, propiconazole, simazine, tebuconazole, thiamethoxam and trifloxystrobin in the water samples throug High Performance Liquid Chromatography (CLAE/EM). In the summer season, the presence of pirimicarb was identified, with a minimum concentration of 0,099 μg L-1 and a maximum of 0,182 μg L-1, malathion, with 0,231 μg L-1 and epoxiconazole, with 0,026 μg L-1. In the autumn season, was quantified azoxystrobin, with a minimum concentration of 0,049 µg L-1 and a maximum of 0,418 µg L-1. In the winter, was verified season the presence of atrazine, with a minimum concentration of 0,017 μg L-1 and a maximum of 0,846 μg L-1, fipronil, with a minimum concentration of 0,330 μg L-1 and maximum 2,404 μg L-1, trifloxystrobin, with a minimum concentration of 0,215 μg L-1 and maximum 0,823 μg L-1, difenoconazole with a concentration of 0,109 μg L-1 and profenofos, with a concentration of 0,851 μg L-1. While in the spring was not quantified pesticides. Finally, it should be noted that although present, none of the pesticides shows a value above the maximum limit established by the Ministry of Health (MS) Consolidation Ordinance Nº 5/2017.