title: Evaluation of heavy metal inhibition of activated sludge by TTC and INT-electron transport system activity tests.
abstract: TTC and INT-electron transport system activity tests were compared for assessing heavy metal inhibition of activated sludge. The median inhibitory concentrations (IC50s) of Cu2+, Zn2+, Cd2+, Hg2+, Ni2+, Pb2+ and Ag+ measured via TTC test were lower than those measured via INT test, which indicates that the INT-electron transport system activity test was less sensitive to heavy metal toxicity than the TTC test. Tested heavy metals brought about similar decrease in TTC-electron transport system activity and COD removal rate, but less decrease in INT-electron transport system activity than COD removal rate, which suggests that the TTC-electron transport system activity is a better parameter for reflecting heavy metal inhibition of activated sludge than INT-electron transport system activity. The ranking of tested heavy metals in order of decreasing toxicity based on TTC test was Hg2+, Cd2+, Cu2+, Ag+, Zn2+, Ni2+ and Pb2+, and the ranking based on INT test was Hg2+, Ag+, Cu2+, Cd2+, Zn2+, Ni2+ and Pb2+.
authors.affiliation: Department of Environmental Engineering, Jilin Architectural and Civil Engineering Institute, Changchun, PR China. jlyinjun@hotmail.com
authors.forename: J
authors.initials: J
authors.lastname: Yin
authors.forename: X J
authors.initials: XJ
authors.lastname: Tan
authors.forename: N Q
authors.initials: NQ
authors.lastname: Ren
authors.forename: Y B
authors.initials: YB
authors.lastname: Cui
authors.forename: L
authors.initials: L
authors.lastname: Tang
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism*; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013053:Spectrophotometry; D013778:Tetrazolium Salts / Q000378:metabolism*; D018675:Toxicity Tests / Q000379:methods; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D045222:Electron Transport Chain Complex Proteins; D019216:Metals, Heavy; D012722:Sewage; D013778:Tetrazolium Salts; C013574:iodonitrotetrazolium; C009591:triphenyltetrazolium