University of Arizona, Department of Environmental and Chemical Engineering, 1133 E. James E. Rogers Way, Harshbarger108, Tucson, AZ, 85721, USA.
Australian Rivers Institute, Griffith School of Environment, Griffith University, Southport, Qld 4222, Australia.
Chemosphere. 2018 Dec;212:182-192. doi: 10.1016/j.chemosphere.2018.07.190. Epub 2018 Aug 3.
Surface waters are becoming increasingly influenced by wastewater effluents due to drought conditions, growing populations, and urbanization. These effluents contain mixtures of trace organic compounds (TOrCs), including bioactive constituents, which are not fully attenuated by conventional wastewater treatment systems. This study investigated the occurrence of glucocorticoid receptor (GR), aryl hydrocarbon receptor (AhR), and estrogen receptor (ER) activity, as well as the overall toxicity to bacteria (BLT-Screen), in the effluent of two wastewater reclamation facilities (WRF) and downstream of the Lower Santa Cruz River, Pima County, Arizona USA, which is dominated by the WRF effluents. The GR, AhR, and ER activities and toxicity to bacteria were determined by in vitro bioassays during four seasons. Bioassay results showed the highest activities at the wastewater outfalls, with activities decreasing downstream of the river. Biological equivalent concentrations ranged from 9 to 170 ng/L dexamethasone-equivalents (DexEQ), 0.1-0.8 ng/L 2,3,7,8-tetrachlorodibenzo-p-dioxin-equivalents (TCDDEQ), and <0.005-0.8 ng/L estradiol equivalents (EEQ) for GR-, AhR- and ER-mediated activity, respectively. This level of biological activity at times exceeded the relevant effects-based trigger value for environmental effects, indicating a potential risk to the receiving environment. Toxicity to bacteria was low at all sites, well below the trigger value of 1.0 TU, which represents an undiluted water sample causing 20% toxicity in the assay. The potential inducing glucocorticoid agonists were further analysed by liquid chromatography coupled to tandem mass spectrometry. Analytical results reveal triamcinolone acetonide as the most abundant glucocorticoid with concentrations up to 38 ng/L. Similar results for DexEQ concentrations calculated from both chemical and bioassay data indicate a successful mass balance for glucocorticoids. This mass balance illustrated lower DexEQ during summer months, which could be due to an increased attenuation from photodegradation.
由于干旱、人口增长和城市化，地表水体受到越来越多的废水排放的影响。这些废水中含有痕量有机化合物（TOrCs）的混合物，包括生物活性成分，这些成分不能被传统的废水处理系统完全去除。本研究调查了两种废水再利用设施（WRF）的废水以及美国亚利桑那州皮马县下圣克鲁斯河下游的糖皮质激素受体（GR）、芳香烃受体（AhR）和雌激素受体（ER）活性以及对细菌的整体毒性（BLT-Screen）的情况，该地区主要受到 WRF 废水的影响。在四个季节的体外生物测定中，测定了 GR、AhR 和 ER 活性以及对细菌的毒性。生物测定结果表明，在废水出水口处的活性最高，随着河流的下游，活性逐渐降低。生物等效浓度范围为 9 至 170ng/L 地塞米松等效物（DexEQ）、0.1 至 0.8ng/L 2,3,7,8-四氯二苯并-p-二恶英等效物（TCDDEQ）和 <0.005 至 0.8ng/L 雌二醇等效物（EEQ）分别用于 GR、AhR 和 ER 介导的活性。这种生物活性水平有时超过了环境影响的相关基于效应的触发值，表明对受纳环境存在潜在风险。在所有地点，细菌的毒性都很低，远低于 1.0TU 的触发值，这代表了在测定中引起 20%毒性的未稀释水样。通过液相色谱串联质谱进一步分析潜在的诱导糖皮质激素激动剂。分析结果表明，曲安西龙乙脂是最丰富的糖皮质激素，浓度高达 38ng/L。从化学和生物测定数据计算得出的 DexEQ 浓度的相似结果表明糖皮质激素的质量平衡良好。该质量平衡表明夏季 DexEQ 浓度较低，这可能是由于光降解增加了其衰减。
