engleski

Cytotoxicity, genotoxicity and mutagenicity testing of wastewater produced by high pressure boat washing

During last twenty years, the antifouling paints based on toxic tributhyltin are being replaced with less toxic compounds. To prevent fouling to boat’s hulls thus minimizing boat transport costs, people invented several possible solutions. Use of paints based on heavy metals is one of them. Annually, boats are being washed using high pressure wash machines thus generating approximately 100 L of wastewater that contains various types of heavy metals. The aim of this study was to test toxicity of such wastewater on human peripheral blood lymphocytes (HPBLs) and Salmonella typhimurium strains TA98 and TA100. In order to test cytotoxicity we have performed differential acridine orange and ethidium bromide vital staining on HPBLs. The results showed significant decrease in cell viability after both 4 h and 24 h exposure period. Genotoxic potential of tested wastewater was evaluated on HPBLs using comet assay. Similar results are observed for both exposure periods, where the percentage of migrated DNA resulted with 2.31-fold increase after 4 h and 1.86-fold increase after 24 h exposure period, compared to vehicle control samples. As models for mutagenicity testing S. typhimurium strains TA98 and TA100 were used. Interestingly, the wastewater failed to induce any significant, reproducible increase either in the presence or absence of metabolizing system S9 mix. The possible explanation of high genotoxicity could be either due to effective repair processes, or relatively high cytotoxicity of tested sample thus not inducing mutagenicity in S. typhimurium strains. In order to give possible solution for this potentially toxic wastewater, we have purified it using ozonation/electrocoagulation treatment processes. The same set of tests was done on purified wastewater where the level of some heavy metals decreased up to 100%. In that manner, the cytotoxicity, genotoxicity, and mutagenicity tests resulted with the same results as detected in vehicle control samples. Taken together, boat washing is potentially hazardous source of heavy metals leaching into sea water. Because of large number of boats and boatyards along the sea coasts it could present threat to environment, marine organisms, and humans, if not treated adequately.

Wastewater ; Cytotoxicity ; Genotoxicity ; Mutagenicity ; Purification methods

nije evidentirano