Cyto-genotoxic effects predict ecotoxicity in plant bioassays and the aquatic organism Artemia salina L.: a case study from a sewage treatment plant

This study evaluated the toxicological and mutagenic potential of water samples from a Wastewater Treatment Plant (WWTP) in Lavras, Minas Gerais, Brazil. Samples were taken from four sites: upstream in the stream (P1), downstream (P2), at the entrance of the treatment station (P3), and at the exit (P4). We conducted physicochemical analyses in water, phytotoxicity tests on plants (Triticum aestivum, Pennisetum glaucum, Lactuca sativa, Raphanus sativus), cytogenotoxicity tests using onion roots (Allium cepa), and Artemia salina immobilization tests. Elevated Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), anionic surfactants, and ammoniacal nitrogen were found at P3 and P4. While germination rates were generally unaffected, P4 inhibited the germination speed of R. sativus. The growth of L. sativa increased in P3 and P4, and of R. sativus in P2, due to more nitrogen and phosphorus. T. aestivum and P. glaucum, however, had their growth inhibited at P4 due to surfactant toxicity. Cytogenotoxicity tests revealed the highest frequencies of micronuclei and nuclear buds in cells exposed to P3 and P4. Additionally, P3 caused 87.5% immobilization of A. salina. These findings suggest that the WWTP is not fully efficient, and its effluent discharge may contribute to eutrophication and genetic mutations in exposed organisms.