Occurrence and removal of benzotriazole ultraviolet stabilizers in a wastewater treatment plant in China.

Abstract

Benzotriazole ultraviolet stabilizers (BZT-UVs) have previously been found in sludge from wastewater treatment plants (WWTPs), which might be potential sources of BZT-UVs to the surrounding environment. In this work, the occurrence and fate of seven emerging 2-hydroxyphenyl substituted BZTUVs were investigated in a Chinese WWTP. This group of hydrophobic BZT-UVs possess log K ow values ranging from 4.31 to 7.67 which could be associated with their fate in WWTPs. Field samples including 24 h flow composites of influent, effluent and grab sludge samples from different treatment processes were collected and analyzed. Concentrations of BZT-UVs dissolved in aqueous-phases were in the range of 4.88 AE 1.35 (UV-234) to 34.5 AE 12.4 ng L À1 (UV-P) in the primary influent, while only UV-P and UV-328 were detected in the final effluent at concentrations of 10.5 AE 6.59 and 2.74 AE 1.73 ng L À1 , respectively. Considering the amount of target BZT-UVs adsorbed to total suspended solids (TSS), the daily mass flux in the primary influent of the WWTP ranged from 22.3 g day À1 (UV-P, 7.99%) to 74.0 g day À1 (UV-234, 26.5%). Total removal efficiency of the integrated treatment process ranged from 89.7% for UV-P to 99.7% for UV-234 suggesting nearly complete removal. Organic solid sedimentation in primary and secondary clarifiers was the dominant elimination route for BZT-UV analogues, which constituted 96.3% of the total removal efficiency. Advanced treatment (using ultraviolet disinfection) in this plant might further contribute to the high removal efficiencies (ranging from 19.6% to 77.3%). Environmental impactBenzotriazole UV stabilizers (BZT-UVs) have received increasing attention due to their potential environmental persistence and bioaccumulation properties. They are high production chemicals that are found in various consumer products. Research into the occurrence and behavior of various BZT-UVs in wastewater treatment plants is still scarce in China, especially for newly identied analogues such as UV-329 and UV-234. In this paper, a detailed investigation into the occurrence and removal of seven widely used BZT-UVs was performed to provide information on the quantity and routes of how BZT-UVs might enter the environment from wastewater treatment plants. Mass balance calculations are applied to both aqueous and solid phases to estimate the removal efficiency of each treatment process, and the possible mechanisms of removal are further discussed.

Food‐Borne Exposure of Juvenile Rainbow Trout (Oncorhynchus mykiss) to Benzotriazole Ultraviolet Stabilizers Alone and in Mixture Induces Specific Transcriptional Changes

“…Both compounds showed respective maximum concentrations of 478 and 824 ng/g dry weight in biosolids from WWTPs, 0.58 and 3 ng/g dry weight in sediments, and 40.9 and 63.1 ng/L in WWTP effluents (Supplemental Data, Table S1). These levels were similar to or higher than concentrations reported in wastewater and biosolid samples in China (Ruan et al 2012; Song et al 2014) and Europe (Langford et al 2015). Further analyses in fish from eastern Canada revealed that UV‐234 and UV‐328 were present at maximum concentrations of 6.86 and 8.1 ng/g lipid weight, respectively, in hornyhead chub homogenates ( Nocomis biguttatus ), and up to 50.1 and 20.7 ng/g wet weight in the liver of white sucker ( Catostomus commersonii ; Lu et al 2016a, 2017a).…”

Biological effects of the benzotriazole ultraviolet stabilizers UV-234 and UV-320 in early-staged zebrafish (Danio rerio)

“…Due to their high consumption volume, BUVSs have been widely detected in surface waters, wastewaters, sewage sludge, and biota (Kameda et al, 2011;Montesdeoca-Esponda et al, 2012;Nakata et al, 2009;Nakata et al, 2010;Nakata et al, 2012;Ruan et al, 2012;Wick et al, 2016;Zhang et al, 2011;Zhao et al, 2017). Among BUVSs, 2-(benzotriazol-2-yl)-4,6-bis(2-phenylpropan-2-yl)phenol (UV-234) ( Figure S1) is one of the most frequently detected BUVSs in environmental samples from this group of chemicals in recent years (Kameda et al, 2011;Ruan et al, 2012;Song et al, 2014;Zhao et al, 2017). It is reported that UV-234 is present in untreated and treated wastewater at concentrations in the low ng/L range (~1.6e37.8 ng/L) (Langford et al, 2015;Lu et al, 2017b;Song et al, 2014;Zhao et al, 2017).…”

Transcriptional and cellular effects of benzotriazole UV stabilizers UV‐234 and UV‐328 in the freshwater invertebrates Chlamydomonas reinhardtii and Daphnia magna

“…Sediment cores collected in the vicinity of the manufacturing plant demonstrated levels in the micrograms per gram dry weight range from 1971 to today, providing evidence of the persistence of these compounds in the environment 30 yr after production had ceased . In addition, the presence of BZT‐UVs has been reported in raw and treated wastewaters around the world from 1 to 76 ng/L and reaching up to 813 ng/g in indoor house dust in the Philippines . Given their lipophilic properties as a result of high octanol—water partition coefficient (log K OW ) values (>7), BZT‐UVs have the potential to bioaccumulate in organisms and to biomagnify through food chains and have been detected in different species of fish at concentrations reaching up to 563 ng/g lipid weight , 220 ng/g lipid weight in mollusks , 2.3 ng/g wet weight in crustaceans , and 64 ng/g wet weight in marine mammals from Asia, the United States, and Canada.…”