Genotoxicity analysis of two halonitromethanes, a novel group of disinfection by-products (DBPs), in human cells treated in vitro.
Halonitromethanes (HNMs) constitute an emerging class of disinfection by-products (DBPs) produced when chlorine and/or ozone are used for water treatment. The HNMs are structurally similar to halomethanes, but have a nitro-group in place of hydrogen bonded to the central carbon atom. Since little information exists on the genotoxic potential of HNMs, a study has been carried out with two HNM compounds, namely trichloronitromethane (TCNM) and bromonitromethane (BNM) by using human cells. Primary damage induction has been measured with the Comet assay, which is used to determine both the repair kinetics of the induced damage and the proportion of induced oxidative damage. In addition, the fixed DNA damage has been evaluated by using the micronucleus (MN) assay. The results obtained indicate that both compounds are genotoxic, inducing high levels of DNA breaks in the Comet assay, and that this DNA damage repairs well over time. In addition, oxidized bases constitute a high proportion of DNA-induced damage (50-75%). Contrarily, no positive effects were observed in the frequency of micronucleus, which measures both clastogenic and aneugenic effects, neither using TK6 cells nor peripheral blood lymphocytes. This lack of fixed genetic damage would minimize the potential mutagenic risk associated with HNMs exposure.
Liviac
Danae
D
Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Edifici Cn, Universitat Autònoma de Barcelona, 08193 Bellaterra, Cerdanyola del Vallès, Spain.
Creus
Amadeu
A
Marcos
Ricard
R
D018929:Cell Culture Techniques; D002460:Cell Line; D020552:Comet Assay; D004249:DNA Damage; D004260:DNA Repair; D004202:Disinfectants; D004203:Disinfection; D004980:Ethane / Q000031:analogs & derivatives* / Q000633:toxicity; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced; D015162:Micronucleus Tests; D009153:Mutagens / Q000633:toxicity*; D009574:Nitro Compounds / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D018508:Water Purification / Q000379:methods / Q000592:standards
D004202:Disinfectants; D006843:Hydrocarbons, Chlorinated; D009153:Mutagens; D009574:Nitro Compounds; D014874:Water Pollutants, Chemical; C533588:bromonitromethane; C100187:chloropicrin; D004980:Ethane