Analysis of the cytotoxicity and mutagenicity of drinking water disinfection by‐products in Salmonella typhimurium

Abstract

We analyzed the cytotoxicity and mutagenicity of the drinking water disinfection by-products (DBPs) bromoform (BF), bromoacetic acid (BA), dibromoacetic acid (DBA), tribromoacetic acid (TCA), chloroform (CF), chloroacetic acid (CA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-furanone (MX), and potassium bromate (KBrO3) in Salmonella typhimurium strains TA98, TA100, and RSJ100 +/- S9. Solvent controls of DMSO and ethanol and a positive control of ethylmethanesulfonate (EMS) were also analyzed. We developed a rapid microplate-based method to determine the cytotoxicity of the DBPs and we determined their mutagenic potencies. The distributions of the rank order for the cytotoxicity and mutagenicity of these DBPs were compared and the structure-function relationships were identified. TA100 -S9 was the most sensitive strain for these DBPs. The rank order of the mutagenic potency adjusted with a cytoxicity factor was MX > BA > EMS > DBA > DCA > CA with TBA, TCA, BF, and CF not mutagenic. From a structure-function perspective, the brominated acetic acids were more cytotoxic and mutagenic than their chlorinated analogs. BA was 150x more mutagenic than CA. The mutagenic potency of the haloacetic acids was inversely related to the number of halogen atoms of the molecule. BA was 36x more mutagenic than DBA. The differential cytotoxicity expressed by the DBPs indicated that a cytotoxicity analysis enhanced the sensitivity of the mutagenicity data, which resulted in an enhanced precision for comparing their relative mutagenic strengths. This information is critical when conducting quantitative structure-function analysis of these hazardous agents.

Antimicrobial egg cleaning by the fringed darter (Perciformes: Percidae:Etheostoma crossopterum): implications of a novel component of parental care in fishes

“…Considering the results from the cytotoxicity assay, the mucus appears to have antiseptic effects on the bacteria. We conclude that the effect is cytotoxic as opposed to cytoinhibitory based on results acquired during assay development and calibration in which treatment wells exhibiting an effect at 210 min had a smaller number of CFUs than treatment wells at 0 min (Kargalioglu et al 2002). It is unclear whether the mucus is fungicidal, inhibits fungal growth or prevents fungal adhesion to the egg surface.…”

“…This assay was modified from that published by Kargalioglu et al (2000Kargalioglu et al ( , 2002. Salmonella typhimurium was assayed because it was the standard microbe used to develop the cytotoxicity assay (Kargalioglu et al 2000(Kargalioglu et al , 2002; 500 m l of log-phase S. typhimurium cells (strain TA100) were grown in 5 ml of LB for 2 h at 37°C while shaking. The cell titre was adjusted to an optical density (OD) of 0.30 at 595 nm.…”

Isolation and Characterization of a Novel Haloacid Permease from Burkholderia cepacia MBA4

“…Haloacetic acids are disinfection by-products (6,20) and have been shown to possess toxic and mutagenic properties (21,38). It is thus reasonable to identify haloacetate dehalogenase genes in various bacteria because the acquisition of the gene helps the bacterium to detoxify and survive (50).…”

Mammalian cell cytotoxicity and genotoxicity analysis of drinking water disinfection by‐products

“…We recently reported the cytotoxicity and mutagenicity of selected DBPs in Salmonella typhimurium [Kargalioglu et al, 2002]. In this study we developed and calibrated assays for cytotoxicity and genotoxicity in Chinese hamster ovary (CHO) cells and used the same set of DBPs for a comparison with the results obtained from the S. typhimurium assays.…”