Cytotoxicity and Mutagenicity Study of Waste and Purified Water Samples from Electroplating Industries Prepared by Use of Ferrous Sulfate and Wood Fly Ash

Toxicological safety of the new purification method for electroplating wastewaters (EWW) has been assessed. Method utilizes waste by–product ferrous sulfate and wood fly ash to scavenge heavy metals from EWW. Energy dispersive X–ray fluorescence (EDXRF) analysis of all samples met the law requirements for safe depositing of waste into the environment. The toxicity study consisted of determination of frequency of bacterial and human cell lines survival and the Ames assay (plate incorporation assay and the preincubation assay). Unexpectedly, data obtained indicate cytotoxicity and slight mutagenic potential of purified water.     Ames assay showed that combination of alkalis and heavy metals present in the water purified with original fly ash and eluates of fly and waste ash were metabolically activated and conjugated with glutathione, resulting in new metabolites active and toxic for the cell. In order to reduce this effect pretreatment of fly ash (partial removal of highly soluble compounds) are necessary prior to its usage for neutralization /coagulation/flocculation processes.

Key Words:

• Ames test
• HEp
• HeLa
• Electroplating wastewater
• Ferrous sulfate
• Wood fly ash.

ACKNOWLEDGMENTS

The authors wish to thank Dr. B. N. Ames for providing bacterial tester strains and Mrs. Maja Osmak, Ph.D., for kindly providing human carcinoma cell lines. The Ministry of Science and Technology (project no. 058013) is gratefully acknowledged for financial support.

Notes

^*Electroplating wastewater before treatment diluted 10 times (EWWBT), purified water with original fly ash (PWW–1) and with rinsed fly ash (PWW–2), water extract of original fly ash (FAE), water extract of waste ash remaining after treatment of wastewaters with original fly ash (WAE) and rinsed fly ash (RWAE) and maximum allowed values for wastewaters suitable for discharge into the environment (MAV–WW), and water extract for the waste materials suitable for deposition on the domestic waste repository (MAV–E).

^*EWWBT—electroplating wastewater before treatment diluted 10 times; PWW–1—purified water with original fly ash; PWW–2—purified water with rinsed fly ash; FAE—water extract of original fly ash; WAE—water extract of waste ash remaining after treatment of wastewaters with original fly ash; RWAE—water extract of waste ash remaining after treatment of wastewaters with rinsed fly ash; NC—negative control; HEp—human epithelial larynx cancer cell line; HeLa—human epithelial cervix cancer cell line.

^*EWWBT—electroplating wastewater before treatment diluted 10 times; PWW–1—purified water with original fly ash; PWW–2—purified water with rinsed fly ash; FAE—water extract of original fly ash; WAE—water extract of waste ash remaining after treatment of wastewaters with original fly ash; RWAE—water extract of waste ash remaining after treatment of wastewaters with rinsed fly ash; TA 98—Salmonella typhimurium, strain TA 98; TA 100—Salmonella typhimurium, strain TA 100; S9—metabolic activator (consisting of liver cytosolic fraction obtained after centrifugation at 9000 g, coenzymes, and buffer); GSH—reduced form of glutathione; PBS—phosphate buffer.