title: Heat shock protein 47 stress responses in Chinese hamster ovary cells exposed to raw and reclaimed wastewater.
abstract: As wastewater reclamation and reuse becomes more widespread, risks of exposure to treated wastewater increase. Moreover, an unlimited number of pollutants can be identified in wastewater. Therefore, comprehensive toxicity assessment of treated wastewater is imperative. The objective of this study was to perform a comprehensive toxicity assessment of wastewater treatment systems using stress response bioassays. This powerful tool can comprehensively assess the toxicity of contaminants. In this study, samples from conventional activated sludge treatment, membrane bioreactors (MBRs) with different pore sizes and sludge retention times (SRTs), rapid sand filtration, coagulation, nano-filtration (NF) and reverse osmosis (RO) were investigated. The results of stress response bioassays confirmed that the secondary effluent showed higher stress response than influent indicating that biological treatment generates toxic compounds. The results obtained from molecular weight fractionation of water samples demonstrated that organic matter with a higher molecular weight fraction (>0.1 μm) causes toxicity in secondary effluent. Furthermore, supernatant from MBR reactors showed toxicity regardless of SRT. On the other hand, stress response was not detected in MBR permeates except for an MBR equipped with a larger pore size membrane (0.4 μm) and with a short SRT (12 days). While rapid sand filtration could not remove the toxic compounds found in secondary effluent, coagulation tests, operated at an appropriate pH, were effective for reducing stress response in the secondary effluent. Experimental findings also showed that stress response was not detected in cases of NF and RO permeate subsequent to MBR treatment.
authors.affiliation: Environmental Engineering Department, Graduate school of Engineering, Hokkaido University, Kita 13 jo Nishi 8Chome, Kita-ku, 060-8628 Sapporo, Hokkaido, Japan. g_mokh@yahoo.fr
authors.forename: Mokhtar
authors.initials: M
authors.lastname: Guizani
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nogoshi
authors.forename: Fahmi
authors.initials: F
authors.lastname: Ben Fredj
authors.forename: Junkyu
authors.initials: J
authors.lastname: Han
authors.forename: Hiroko
authors.initials: H
authors.lastname: Isoda
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Funamizu
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004784:Environmental Monitoring; D005374:Filtration / Q000379:methods; D050958:HSP47 Heat-Shock Proteins / Q000378:metabolism*; D018570:Risk Assessment; D014865:Waste Disposal, Fluid / Q000379:methods; D014873:Water Pollutants / Q000633:toxicity*
chemical_list: D050958:HSP47 Heat-Shock Proteins; D014873:Water Pollutants