The assessment of genotoxic effects of wastewater from a fertilizer factory

Abstract

In this study we investigated cytotoxic, mutagenic and genotoxic effects of different concentrations of wastewater from the phosphoric gypsum depot near the factory for fertilizing agents 'INA Petrokemija' (Kutina, Croatia). The Ames test was performed on Salmonella typhimurium TA98 and TA100 strains, in the presence of S9 mix, glutathione and buffer, respectively. Cytotoxicity was studied on human laryngeal carcinoma cells (HEp2) and human cervical cells (HeLa). The level of lipid peroxidation in these two cell lines was evaluated in parallel. To establish the levels of primary DNA damage, the alkaline comet assay was performed on treated human peripheral blood leukocytes. No mutagenic effects of phosphoric gypsum on Salmonella typhimurium strains in the presence of S9 mix, GSH or PBS were observed. However, strong cytotoxic effect was observed on both human cell lines when they were treated with different concentrations of wastewater. Lipid peroxidation was induced and increased by prolonged time of incubation, highlighting that the damage was not repaired, but increased with the time of incubation. The results of the alkaline comet assay indicate significant DNA damaging potential of wastewater for human leukocytes. Since phosphoric gypsum transport water in its present composition and acidity is highly toxic and acts as prooxidant, causing free radicals formation and DNA damage, urgent neutralization/purification of the wastewater to a level acceptable for disposal into the environment is mandatory.

Inertisation of galvanic sludge with calcium oxide, activated carbon, and phosphoric acid

“…All three treatment methods can effi ciently convert hazardous waste into inert material and reduce its adverse effects on the environment and human health (13)(14)(15)(16)(17)(18)(19). Inertization with powdered activated carbon showed best performance (Figure 2).…”

“…Although there are more than a hundred electroplating facilities in Croatia, most of them zinc plating, there either recovery or inertisation of electroplating sludge have been regulated (12). As this sludge contains high concentrations of zinc in the leachate, and the pH value is usually below 3, it poses a considerable threat to the environment and people, which has been confi rmed by toxicological tests on various bio-systems for the concentration of zinc that are even lower than 2 mg L -1 (13)(14)(15)(16)(17)(18)(19). Oreščanin et al (20) developed the fi rst method to treat electroplating sludge in Croatia that is based on solidifi cation/stabilisation of sludge with CaO in order to convert hazardous waste into inert material.…”

In Vitro Genotoxicity of Settat Town Landfill Leachate, Morocco

“…The MN test is a well-known and validated endpoint that can predict increased cancer risk in a human population (22). This test has an advantage over tests with bacteria such as the Ames assay, which are not sensitive enough for water and soil leachate genotoxicity evaluations, especially when heavy metal contamination is anticipated (12,23). Nowadays the MN test is sometimes accompanied by counting apoptotic and necrotic cells, nuclear buds, and nucleoplasmic bridges (the cytome assay) (24).…”

In Vitro Genotoxicity of Wastewaters from the Town of Settat, Morocco

“…as a result of disturbances in the mitotic spindle). Furthermore, it can be more sensitive than the bacterial Ames assay, especially when heavy metal contamination is anticipated (15,16). Recently, an inter-laboratory comparison study has also demonstrated that the in vitro micronucleus test is indeed very suitable for routine wastewater testing (17).…”

“…This fi nding is in accordance with earlier investigations. Among recently published studies, reference can be made to Durgo et al (16) who investigated wastewater polluted by fertilisers from a phosphoric gypsum depot near a factory in Croatia. Using the alkaline comet assay, they found a signifi cant DNA damaging potential of wastewater on human leukocytes, but no effect in the Ames test.…”