Single and mixture cytogenetic effects evaluation of atrazine and glyphosate herbicides at environmentally relevant concentrations on Allium cepa root meristem cells

Abstract

The mixture of pesticides is employed to obtain other mechanisms of action on target organisms. The herbicides atrazine and glyphosate are used worldwide to control weeds in agricultural crops, and their indiscriminate use results in their constant presence in the environment. In this sense, this study aimed to evaluate the cytotoxic potential, the presence of chromosomal aberrations and nuclear abnormalities, and the frequency of micronuclei of active ingredients and commercial formulations of the herbicides atrazine (AT = 2 and 25 μg L-1) and glyphosate (GF = 65 and 160 μg L-1) isolated and in mixture (MIX = 2 + 65 and 25 + 160 μg L-1). Allium cepa root meristem cells were used as the test organism to evaluate environmentally relevant concentrations. Treatments containing the herbicides inhibited the mitotic index (ATAI2: 9.40 ± 1.36; GFAI65: 8.58 ± 1.10; MIXAI2+65: 6.99 ± 0.57; GFAI160: 9.77 ± 1.08; ATCOM25: 7.40 ± 1.38; GFCOM160: 8.26 ± 0.79) and showed chromosomal aberrations and nuclear abnormalities (ATAI2: 0.85 ± 0.17; ATCOM2: 0.97 ± 0.18; GFCOM65: 1.00 ± 0.18; MIXCOM2+65: 1.09 ± 0.25; ATAI25: 0.82 ± 0.17; GFAI160: 0.87 ± 0.23; MIXAI25+160: 0.95 ± 0.19; ATCOM25: 0.67 ± 0.19; MIXCOM25+160: 0.80 ± 0.25), indicating the cytotoxic/genotoxic potential of these herbicides. Mutagenic effects were seen in the mixture of the active ingredients of the herbicides at the lowest concentration tested (MIXAI2+65: 0.70 ± 0.57). These results indicate that the isolated herbicides and their mixture directly affect the genetic material. Therefore, we suggest reviewing the acceptable limits of these herbicides in the environment, emphasizing the importance and care required for properly handling these products to minimize environmental and human health risks.