Toxicity assessment of chlorinated wastewater effluents by using transcriptome-based bioassays and Fourier transform mass spectrometry (FT-MS) analysis.
Effects of chlorination on the toxicity of wastewater effluents treated by activated sludge (AS) and submerged membrane bioreactor (S-MBRB) systems to HepG2 human hepatoblastoma cells were investigated. In addition to the cytotoxicity and genotoxicity assays, the DNA microarray-based transcriptome analysis was performed to evaluate the change in types of biological impacts on HepG2 cells of the effluents by chlorination. Effluent organic matter (EfOM) and disinfection by-products (DBPs) were also characterized by using Fourier transform mass spectrometry (FT-MS). Although no significant induction of genotoxicity was observed by chlorination for both effluents, the chlorination elevated the cytotoxicity of AS effluent but reduced that of S-MBRB effluent. The FT-MS analyses revealed that more DBPs including nitrogenated DBPs (N-DBPs) were formed in the AS effluent than in the S-MBRB effluent by chlorination, supporting the increased cytotoxicity of AS effluent. The lower O/C ratio of S-MBRB EfOM suggests that a large number of organic molecules were detoxified by chlorination, which consequently decreased the cytotoxicity of S-MBRB effluent. Integration of all the results highlights that both cytotoxicity and biological impacts of chlorinated wastewater effluents were clearly dependent on the EfOM characteristics such as DBPs and O/C ratio, namely, on types of treatment systems.
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
Toshikazu
T
Fukushima
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
Hiroe
H
Hara-Yamamura
Research Center for Water Environment Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Makoto
M
Urai
Research Center for Water Environment Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Ikuro
I
Kasuga
Research Center for Water Environment Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Futoshi
F
Kurisu
Center for Environmental Nano and Bio Engineering, Hokkaido University, Sapporo 060-8628, Japan.
Taro
T
Miyoshi
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.
Katsuki
K
Kimura
Center for Environmental Nano and Bio Engineering, Hokkaido University, Sapporo 060-8628, Japan.
Yoshimasa
Y
Watanabe
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan. Electronic address: sokabe@eng.hokudai.ac.jp.
Satoshi
S
Okabe
D001681:Biological Assay; D004203:Disinfection / Q000379:methods; D005583:Fourier Analysis; D054879:Halogenation; D056945:Hep G2 Cells / Q000187:drug effects; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D020411:Oligonucleotide Array Sequence Analysis; D018675:Toxicity Tests / Q000379:methods*; D059467:Transcriptome; D062065:Wastewater / Q000737:chemistry / Q000633:toxicity*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods
D062065:Wastewater
Chlorination; Cytotoxicity; DBPs; DNA microarray; Fourier transform mass spectrometry; Wastewater effluents