Occurrence and fate of substituted diphenylamine antioxidants and benzotriazole UV stabilizers in various Canadian wastewater treatment processes

Substituted diphenylamine antioxidants (SDPAs) and benzotriazole UV stabilizers (BZT-UVs) are additives used in industrial and consumer products to prevent degradation or color change of materials, but their environmental fate and disposition are not well characterized. In this study, SDPAs and BZT-UVs were analyzed in 68 liquid and 39 solid samples collected from 9 wastewater treatment plants (WWTPs) in Canada to investigate the occurrence and fate of these contaminants. The median concentrations of Sigma SDPAs and Sigma BZT-UVs was 483 and 76.2 ng L-1 in influent, 28.4 and 4.84 ng L-1 in effluent, and 2750 and 457 ng g(-1) in biosolids (dry weight), respectively. Dinonyl-diphenylamine (C9C9) was the predominant congener of SDPAs in all matrices (>40%). For target BZT-UVs, the major components were 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (UV234) and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV328). SDPAs and BZT-UVs were effectively removed (>90%) from the liquid stream in most WWTPs mainly through sludge sorption and separation, but biotransformation, UV treatment and filtration may also contribute to removal of some contaminants in advanced treatment plants. In contrast, the removal efficiency of target contaminants using chemically assisted primary treatment was low, likely due to the short hydraulic retention time of this site. Our results suggest that wastewater effluent is a vector of SDPAs and BZT-UVs to the aquatic environment. The results also highlight the high concentrations of SDPAs and BZT-UVs associated with the solid stream in WWTPs, which could affect the beneficial use of biosolids (e.g., compost or land applications) Crown Copyright (C) 2017 Published by Elsevier Ltd. All rights reserved.

取代二苯胺抗氧化剂（SDPAs）和苯并三唑紫外线稳定剂（BZT - UVs）是用于工业和消费品中的添加剂，用于防止材料降解或变色，但其在环境中的归宿和处置情况尚未得到很好的表征。在这项研究中，对从加拿大9个污水处理厂（WWTPs）采集的68个液体样本和39个固体样本中的SDPAs和BZT - UVs进行了分析，以研究这些污染物的存在情况和归宿。∑SDPAs和∑BZT - UVs在进水口中的中位浓度分别为483纳克/升和76.2纳克/升，在出水中分别为28.4纳克/升和4.84纳克/升，在生物固体（干重）中分别为2750纳克/克和457纳克/克。二壬基 - 二苯胺（C9C9）是所有基质中SDPAs的主要同系物（>40%）。对于目标BZT - UVs，主要成分是2 -（2H - 苯并三唑 - 2 - 基）- 4,6 - 双（1 - 甲基 - 1 - 苯乙基）苯酚（UV234）和2 -（2H - 苯并三唑 - 2 - 基）- 4,6 - 二叔戊基苯酚（UV328）。在大多数污水处理厂中，SDPAs和BZT - UVs主要通过污泥吸附和分离从液流中有效去除（>90%），但生物转化、紫外线处理和过滤也可能有助于一些先进处理厂中某些污染物的去除。相比之下，使用化学辅助一级处理对目标污染物的去除效率较低，这可能是由于该处理场所的水力停留时间较短。我们的研究结果表明，污水排放是SDPAs和BZT - UVs进入水生环境的一个载体。研究结果还凸显了污水处理厂中与固体流相关的SDPAs和BZT - UVs浓度较高，这可能会影响生物固体的有益利用（例如，堆肥或土地应用）。版权所有©2017，爱思唯尔有限公司出版。保留所有权利。