RESEARCH ARTICLE Acute ecotoxicity and genotoxicity assessment of two wastewater treatment units Gleison de Souza Celente 1 & Gustavo Stolzenberg Colares 1 & Priscila da Silva Araújo 2 & Ênio Leandro Machado 3 & Eduardo Alexis Lobo 3 Received: 4 July 2019 /Accepted: 5 December 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Water contamination by discharge of untreated or poorly treated wastewater into water bodies is a current issue that may cause harm to humans. Water quality assessment targets general parameters, which often misleads to underestimation of their impli- cation in the environment. Acute and genotoxicity assays using Daphnia magna is a reliable tool for testing deleterious effects of wastewater exposure. This paper aimed at evaluating acute ecotoxicity as well as genotoxicity of a biological treatment system composed by an anaerobic bioreactor (AR), algal turf scrubber (ATS), followed by two downflow constructed wetlands (CW). The university’ s wastewater treatment plant (WWTP) composed by an equalization tank (ET), an upflow anaerobic sludge blanket (UASB), followed by an aerobic bioreactor (AB) was also assessed for acute and genotoxicity. Our results showed the acute ecotoxicity ranged from moderately to extremely toxic, and from nontoxic to moderately toxic for ET and AB. For AR, most samples were moderately toxic. The outflow from ATS and CW’ s tanks completely eliminated acute toxicity and genotoxicity evidencing that the proposed system combining ATS and vertical CWs is suitable for treating sanitary wastewater. Keywords Acute toxicity . Genotoxicity . Algae turf scrubber . Daphnia magna . Constructed wetlands Introduction Water contamination by discharge of untreated or poorly treat- ed wastewater into water bodies is a current issue that may cause harm to humans (WHO 2015) and most concerned in developing countries, where treatment systems are still scarce. Brazilian sewerage system comprises roughly 56% of the pop- ulation and northern region is even worse, where merely 10% of the inhabitants are encompassed by the sewerage system (Machado et al. 2016). As consequence, most of the domestic wastewater produced in Brazil is disposed into water bodies and/or on soil without any level of treatment, which jeopar- dizes surface and underground water quality. Nutrients, heavy metals, and pharmaceutical and health care products are among the contaminants that may account for human diseases, eutrophication, stress of aquatic life, and water shortage (Gorazda et al. 2013, Scholz et al. 2013). Rural residences are the most neglected by sewerage system, as they are not covered by centralized wastewater treatment plants (WWTP) on the account of its related onerous cost with collection net- work (Nogueira et al. 2009). In fact, 70% of the population that does not have access to sanitation facilities is located in rural areas (WHO 2014). In Brazil, the Resolutions 357 and 430, enacted in 2005 and 2011, respectively, establish guidelines and standards for or- ganic, inorganic, biological, and physical parameters that must be accomplished before wastewater discharge into water bod- ies. The limits are aligned according to the classification for the specific water body that receives the effluent (CONAMA 357 2005, CONAMA 430 2011). However, water quality as- sessment targets general parameters, which often misleads to underestimation of their implication in the environment, con- sidering that water ecosystems are contaminated by a vast of Responsible editor: Philippe Garrigues * Gleison de Souza Celente gleison_celente@hotmail.com 1 Environmental Technology, University of Santa Cruz do Sul (UNISC), Avenida Independência, 2293, Santa Cruz do Sul, Rio Grande do Sul 96815-900, Brazil 2 Biological Sciences, University of Santa Cruz do Sul (UNISC), Santa Cruz do Sul, Brazil 3 Environmental Technology Program (Master and Doctoral courses), University of Santa Cruz do Sul (UNISC), Santa Cruz do Sul, Brazil Environmental Science and Pollution Research https://doi.org/10.1007/s11356-019-07308-y