N,N-Diethyl-meta-toluamide (DEET) and methylparaben (MP) are common ingredients used in personal care products (PCPs), the new contaminants of emerging concerns. These two target compounds have attracted increasing attention due to their occurrence, persistence, ubiquitous exposure to humans and the potential ecological concerns. Here, we report fate and transformation of DEET and MP with chlorine, a common disinfectant in water treatment. Basically, this work aims to address the biological concerns, transformation pathway and the correlation between transformation products and elevated bioactivity. The bioactivity including microtoxicity, genotoxicity and estrogenic activity were respectively evaluated with three in-vitro bioassays, Microtox, SOS/umu and Yeast Estrogen Screen. The results show that the microtoxicity is substantially elevated after chlorination of DEET and MP, while the genotoxicity remains constantly low during chlorination. It is also observed that the estrogenic activity of MP is mitigated after reaction with chlorine. Additionally, a number of transformation products were detected and tentatively identified with exact mass values, isotope patterns and MS/MS fragmentations obtained by UPLC-MS/MS. It is believed that transformation products were formed via oxidation and de-alkylation during DEET chlorination, and via electrophilic substitution and dimerization for MP chlorination. Ultimately, the correlation study verifies that the carbamate compounds formed from DEET chlorination and mono- and di-chlorinated parabens formed from MP chlorination are identified as the trouble-makers being responsible for the increased microtoxicity.

Bioactivity-oriented approach to investigate fate and transformation of selected personal care products during chlorination

253rd National Meeting (2017)

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