Concentrations and Composition Profiles of Benzotriazole UV Stabilizers in Municipal Sewage Sludge in China

The environmental contamination and fate of benzotriazole UV stabilizers (BZTs) have received increasing attention due to their large production volume and wide usage in various consumer and industrial products. In the present work, 60 municipal sewage sludge samples from wastewater treatment plants (WWTPs) in 33 cities in China were collected to investigate the occurrence and distribution of 9 frequently used BZTs. The most dominant analogue was 2-[3,5-bis­(1-methyl-1-phenylethyl)-2-hydroxyphenyl]­benzotriazole (UV-234) at a median concentration of 116 ng/g (dry weight) and accounted on average for 27.2% of total BZTs. The abundance was successively followed by 2-(2-hydroxy-5-<i>tert</i>-octylphenyl)­benzotriazole (UV-329, average 24.3%), 2-(2-hydroxy-3-<i>tert</i>-butyl-5-methylphenyl)-5-chlorobenzotriazole (UV-326, average 22.2%), 2-(3,5-di-<i>tert</i>-amyl-2-hydroxyphenyl)­benzotriazole (UV-328, average 17.7%), and 2-(2-hydroxy-5-methylphenyl)­benzotriazole (UV-P, average 6.6%), with median concentrations of 66.8, 67.8, 57.3, and 20.6 ng/g, respectively. 5-Chloro-2-(3,5-di-<i>tert</i>-butyl-2-hydroxyphenyl)­benzotriazole (UV-327) and 2-(3-<i>sec</i>-butyl-5-<i>tert</i>-butyl-2-hydroxyphenyl)­benzotriazole (UV-350) had low detection frequency, while 2-(3,5-di-<i>tert</i>-butyl-2-hydroxyphenyl)­benzotriazole (UV-320) and 2-(5-<i>tert</i>-butyl-2-hydroxyphenyl)­benzotriazole (UV-PS) were not detectable in any sample. To our knowledge, this is the first study reporting the occurrence of UV-234, UV-329, and UV-350 in sewage sludge in China. Significant correlations were found among the BZT concentrations and also with a WWTP characteristic (daily treatment volume). Furthermore, results from degradation prediction and multimedia fate simulation based on a quantitative structure–property relationship (QSPR) model at screening level also implied that the commercial BZT chemicals and their plausible transformation products might be persistent in the environment

Hazy Weather-Induced Variation in Environmental Behavior of PCDD/Fs and PBDEs in Winter Atmosphere of A North China Megacity

Haze is a serious pollution problem during the wintertime in North China. In this study, we investigated how the periodic cycle of winter haze events affect the environmental behaviors of two typical persistent organic pollutants, namely, polychlorinated dibenzo-<i>p</i>-dioxins and dibenzofurans (PCDD/Fs) and polybrominated diphenyl ethers (PBDEs), in the atmosphere of a typical megacity, Beijing. The average atmospheric concentrations of the total di- to octa-CDD/Fs (∑PCDD/Fs: 378.0 pg/m³) and the total mono- to nona-BDEs (∑_9hPBDEs: 166.5 pg/m³) during haze episodes increased by 3.6-fold and 1.9-fold compared with those during the nonhaze periods, respectively; and their concentrations both linearly increased with PM_2.5 levels and decreased as a power function of the atmospheric boundary layer height. The elevated concentrations could be clearly attributed to the vertically sinking motion of airflow in the midlower troposphere. When a haze event occurred, the partitioning rate of PCDD/Fs and PBDEs into particles was reduced; the largest fraction of the particle-bound ∑PCDD/Fs was shifted from ultrafine particles to accumulation mode particles; and a steady-state model (Li-Ma-Yang model) satisfactorily described the gas-particle partitioning of the PCDD/F and PBDE homologues. The inhalation exposure risk evaluation indicated that special attention should be paid to the increased cancer risk induced by the elevated inhalation intake of PCDD/Fs during haze episodes