RESUMO
Munim River is a small basin (15,918.04 km2, 320,000 inhabitants) in northeastern Brazil (Maranhão state), whose water quality has been threatened by pesticides, untreated domestic and industrial wastewater discharges, and solid waste disposal ( Presoti and Cutrim, 2011 ). These pollutants may bring several problems to the aquatic biota, such as mutagenic and carcinogenic effects ( Bolognesi and Hayashi, 2011 ) including risks to human health. Therefore, it is critical to understand the potential impacts of xenobiotics on this river basin, especially their genotoxic and mutagenic effects. We investigated the genotoxic and mutagenic potential of the Munim River waters to assess the impact of the presence of xenobiotics on the aquatic biota.(AU)