Volume 13, No. 3, June 2013, Pages 1002-1008 PDF(237 KB)
Toxicity Evaluation of Fly Ash by Microtox®
San-Chyi Chang1, Ya-Fen Wang2, Sheng-Jie You2, Yi-Ming Kuo3, Cheng-Hsien Tsai4, Lin-Chi Wang5, Po-Yen Hsu2
1 Department of Applied Mathematics, Chinese Culture University, Taipei 111, Taiwan
2 Department of Bioenvironmental Engineering, Chung Yuan Christian University, Chung-Li, 320, Taiwan
3 Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, Tainan 717, Taiwan
4 Department of Chemical and Materials Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan
5 Department of Chemical and Materials Engineering, Cheng Shiu University, Kaohsiung 833, Taiwan
Fly ash samples from a cooling tower were extracted after incinerating plastic solid waste (PSW) and organic liquid waste (OLW) by n-Hexane or dichloromethane/n-Hexane mixtures to evaluate the toxicity. The metal and PCDD/Fs were analyzed by ICP OES and HRGC/HRMS, respectively. The toxicity of the extracted fly ash was evaluated by Microtox®. The results showed the environmental risk factor (ERF) of Hg in PSW fly ash was the highest compared to other metals, by more than 60%. Additionally, the acute toxicity tests of the fly ash showed that dichloromethane/n-hexane extracts were all very toxic, except for the PSW-1 obtained through Soxhlet extraction following the column clean-up procedure. The n-Hexane extracts for OLW-1 obtained through Soxhlet extraction following the column clean-up procedure were extremely toxic. There were no significant relationships among the concentrations of the regulated heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn), PCDD/Fs concentration and the TU values in the toxicity test. Furthermore, the results of the statistical analysis showed that there were significant differences in the results of the Microtox test with regard to the solvents, solutes and various extraction methods. However, it is remains a complicated process to differentiate between the various compounds in order to produce accurate results with regard to acute toxicity in the fly ash, and thus this issue warrants further investigation.
Microtox test; Toxicity; Extraction; Fly ash.