Genotoxicity evaluation of domestic sewage in a municipal wastewater treatment plant

Abstract

An evaluation of the genotoxicity of domestic sewage was carried out in a municipal wastewater treatment plant. The study was carried out using Allium cepa root tip cells through cytological parameters such as aberrant cells in anaphase-telophase and the mitotic index, and the fish species Oreochromis niloticus and Tilapia rendalli, through the index of micronuclei in peripheral erythrocytes. In the Allium test, each of the four stages of the wasterwater treatment routine was analyzed, i.e., crude sewage, primary effluent, secondary effluent, and tertiary effluent. O. niloticus and T. rendalli specimens were maintained in an aquarium continuously receiving the final effluent, in an open system, before being discharged into Lake Paranoá. For micronuclei analysis, blood samples were drawn after 7, 21, 60, 102 and 142 days, respectively, in controlled conditions. The numbers of aberrant cells found in the Allium test did not differ among the four stages tested, nor when compared with the control. At all stages, the most concentrated sample was more toxic than the respective diluted samples, as demonstrated by the decreased mitotic index. Different sampling of the same group of fish revealed no increase in the micronuclei frequency, regardless of the period of exposure. A correlation between long-term exposure and micronuclei induction was not found either

Evaluation of genotoxicity and cytotoxicity of water samples from the Sinos River Basin, southern Brazil

“…In the lower course the demographic density is high and one of the main environmental problems is the discharge of untreated domestic sewage in tributaries and in the main river (Blume et al, 2010). The results of the present study are in agreement with findings reported by Grisolia et al (2005) and Grisolia and Starling (2001), who also did not observe significant increase in DNA damage in fish captured in areas under influence of sewage treatment plant discharges, and in fish exposed to the final effluent of a municipal wastewater treatment plant, respectively.…”

Evaluating wastewater‐induced plant genotoxicity using randomly amplified polymorphic DNA

“…Besides, several studies have revealed that TWW often still contains mutagens (genotoxic substances) that can not only injure the integrity of the genome of organisms but also negatively affect the expression of DNA directly or indirectly (Shugart and Theodorakis, 1994;Filipic and Toman, 1996;Grisolia et al, 2005). This leads to an increase in different types of tumors and subsequently an alteration in the genetic variability of the exposed populations over time (Zhiyi and Haowen, 2004).…”

“…They are good indicators of cytogenetic and mutagenic effects which can be applied both indoors and outdoors. Therefore, mutagenic activity of wastewater and other pollutants has been tested with different plant systems such as Allium cepa, Arabidopsis thaliana, Hordeum vulgaris, Vicia faba, and Zea mays (Cabrera and Rodriguez, 1999;Nielsen and Rank, 2004;Grisolia et al, 2005;Ma et al, 2005;Abdel Migid et al, 2007). With these systems, chromosome aberration assays, mutation assays, and search for chlorophyll-deficient mutants and chlorophyll spot mutation were performed.…”

Bioassays with Plants in the Monitoring of Water Quality

“…Other works also observed the environmental impact of the presence of heavy metals in rivers, lakes and soil aqueous extracts [30][31][32][33][34]. In addition to the domestic sewage [26,[35][36][37], industrial effluents are also historically impacting: [38] submitted seeds of A. cepa to the effluent from a textile industry and observed a mutagenic effect, the type of cell damage may be transmitted to subsequent generations, possibly affecting the organism as a whole, as well as the local biota exposed to the effluent discharge. If the damage results in cell death, the development of the organism may be affected, which could also lead to its death.…”