Qualidade da água utilizada na aplicação de agrotóxicos no município de Sete de Setembro-RS

Abstract

The physicochemical characteristics of water are of the utmost importance when preparing the mixture for pesticide application. The aim of this study was to analyze the quality of the water used for pesticide application in the municipality of Sete de Setembro, RS, and to assess its physical and chemical attributes. 32 water samples from sources were collected, which the farmers in the municipality used for the preparation of solutions. The samples were analyzed for pH, turbidity, electrical conductivity, and water hardness.The pH found was not below 7, with an average pH of 7.9, indicating that these waters are alkaline and depend on the use of pH reducers. The hardness values classified 25% of the artesian well waters as very soft, 45.8% as soft and 29.2% as semi-hard, and have a high degree of correlation with pH and EC, due to the presence of salts. The electrical conductivity values are quite high, indicating that there are a lot of dissolved ions. The turbidity data obtained qualified the samples as crystal clear water. The hardness values for the water from the subsurface sources classified 12.5% as very soft, 75% as soft and 12.5% as semi-hard. The electrical conductivity values are also quite high, indicating that there is a high level of soluble solids. The turbidity data obtained qualified samples 2, 3 and 4 as turbid water, as they were waters from dams that contained high levels of dissolved solids. In general, the water used by the producers has inadequate characteristics for the use of pesticides, requiring the use of adjuvants to correct the ideal water parameters recommended by the manufacturers, such as pH reducers, chelating agents, among others. This increases the efficiency of the application and control of the target, and can reduce the super dosing constantly used by farmers.