Examining Mixtures of Disinfection By-Products: Rat Study Shows No Effects on Reproduction

Konkel, Lindsey

doi:10.1289/ehp.123-a159

Cited by 1 publication

(1 citation statement)

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“…Most studies have focused on the toxicity endpoints of genotoxicity, carcinogenicity, and reproductive effects related to health effects (Villanueva et al 2015). The toxicities of several mixtures of disinfection by-products in rats have been investigated, and pregnancy loss and eye malformations have been detected in rat offspring after gestational exposure to mixtures of regulated disinfection by-products; male rats significantly increase the incidence of retained nipples and impaired sperm motility (Narotsky et al 2008(Narotsky et al , 2011(Narotsky et al , 2012(Narotsky et al , 2015Konkel 2015). In addition, a comprehensive study has indicated that disinfection by-product mixtures have implications for the potential developmental, reproductive, or carcinogenic health of humans (Simmons et al 2008).…”

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confidence: 99%

Concentration Addition, Independent Action, and Quantitative Structure–Activity Relationships for Chemical Mixture Toxicities of the Disinfection By products of Haloacetic Acids on the Green Alga Raphidocelis subcapitata

Qin

Liu

Zhang

et al. 2021

Enviro Toxic and Chemistry

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The potential toxicity of haloacetic acids (HAAs), common disinfection by products (DBPs), has been widely studied; but their combined effects on freshwater green algae remain poorly understood. The present study was conducted to investigate the toxicological interactions of HAA mixtures in the green alga Raphidocelis subcapitata and predict the DBP mixture toxicities based on concentration addition, independent action, and quantitative structure–activity relationship (QSAR) models. The acute toxicities of 6 HAAs (iodoacetic acid [IAA], bromoacetic acid [BAA], chloroacetic acid [CAA], dichloroacetic acid [DCAA], trichloroacetic acid [TCAA], and tribromoacetic acid [TBAA]) and their 68 binary mixtures to the green algae were analyzed in 96‐well microplates. Results reveal that the rank order of the toxicity of individual HAAs is CAA > IAA ≈ BAA > TCAA > DCAA > TBAA. With concentration addition as the reference additive model, the mixture effects are synergetic in 47.1% and antagonistic in 25%, whereas the additive effects are only observed in 27.9% of the experiments. The main components that induce synergism are DCAA, IAA, and BAA; and CAA is the main component that causes antagonism. Prediction by concentration addition and independent action indicates that the 2 models fail to accurately predict 72% mixture toxicity at an effective concentration level of 50%. Modeling the mixtures by QSAR was established by statistically analyzing descriptors for the determination of the relationship between their chemical structures and the negative logarithm of the 50% effective concentration. The additive mixture toxicities are accurately predicted by the QSAR model based on 2 parameters, the octanol–water partition coefficient and the acid dissociation constant (pKa). The toxicities of synergetic mixtures can be interpreted with the total energy (ET) and pKa of the mixtures. Dipole moment and ET are the quantum descriptors that influence the antagonistic mixture toxicity. Therefore, in silico modeling may be a useful tool in predicting disinfection by‐product mixture toxicities. Environ Toxicol Chem 2021;40:1431–1442. © 2021 SETAC

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