Removal of Natural Free Estrogens and their Conjugates in a Municipal Wastewater Treatment Plant

Abstract

Removal of natural free estrogens and estrogen conjugates in a municipal wastewater treatment plant (WWTP) was investigated and analyzed by GC-MS, in which estrogen conjugates were first transformed to their corresponding free estrogens with an acid solvolysis procedure before their analysis. Natural free estrogens, E1-3-sulfate (E1-3S), and E3-3-sulfate (E3-3S) were detected with high concentrations in both the influent and effluent of the primary settling tank (PS), while no estrogen glucuronides were detected in any of the monitored wastewater samples. Regarding their removal efficiencies, all were almost completely removed, except for E1 with only a minor decrease. The estrogenic/androgenic removal of the same WWTP was also evaluated with estrogen receptor (androgen receptor) (ER (AR))-binding assays, in which the removal efficiencies for E2 equivalents (EEQ) or testosterone equivalents (TEQ) were 68.5 and 72.2%. In addition, the chemically calculated EEQ from natural estrogens were about 20.6-39.3% that of the ER-binding assay, in which E3 contributed the biggest proportion in both the influent and PS, while the calculated value of E1 increased from only 6.7% in the influent to as high as 20.6% in the effluent. IntroductionRegarding possible adverse effects on humans and wildlife, endocrine disrupting compounds (EDCs) have been extensively monitored and detected in different environmental samples [1][2][3][4][5]. In municipal wastewater treatment plants (WWTPs), natural estrogens are regarded as one of the most important sources, which have been widely studied [6][7][8]. Although estrogens in human urine were mainly in their sulfate/glucuronide conjugates [9], they were believed to have been bio-transformed to their free estrogens by fecal bacteria before they reach WWTPs [10]. However, much recent studies have shown that estrogen conjugates existed not only in the influent of WWTPs, but also in the effluent [11][12][13]. As estrogen conjugates in effluents with low estrogenic potencies will be further bio-transformed to their free estrogens after their entry into the receiving bodies. These conjugates can be expected to act with the same function as their corresponding free estrogens in the effluent, which may have adverse effects on the aquatic organisms. Therefore, removal performance for both free estrogens and their conjugates in wastewater by WWTPs should be evaluated.Although LC-MS/MS has been applied to environmental samples for simultaneous analysis of free estrogens and their conjugates [11][12][13], it is not as widely used as GC-MS due to its higher price. Moreover, as estrogen conjugates are highly polar compounds, purification procedures to handle them in wastewater samples were complex or the recovery efficiencies were very poor [13][14][15][16]. Analytical methods for estrogen conjugates by LC-MS/MS without purification procedures were also available with a low detection limit, but on these occasions ion suppression phenomena are likely to occur [17,18]. In a previous work, simultaneous anal...

Influence of Hydraulic Retention Time, Sludge Retention Time, and Ozonation on the Removal of Free and Conjugated Estrogens in Japanese Activated Sludge Treatment Plants

“…A high‐effluent concentration may reflect de‐conjugation of conjugated metabolites during the treatment process . Reported E1 and E2 concentrations were in accordance with previous observations . E1 values were similar to the previously reported concentrations in Japanese STP, where 66 ng/L for influents and 80 ng/L for effluents were reported.…”

Removal of Natural Estrogens and Their Conjugates in Municipal Wastewater Treatment Plants: A Critical Review

“…Natural estrogens in urine are mainly in their conjugated forms. Some have proposed these conjugates could be cleaved before WWTP entry, however, sophisticated analytical methods have yielded increasing evidence that estrogen conjugates exist in both raw municipal wastewater and some treated effluents. ,− There are two reasons for paying attention to estrogen conjugates with weak estrogenic potencies. First, estrogen conjugates may adversely affect the environment, as they can be biotransformed into their corresponding free estrogens once entering the natural environment.…”

Activity measurement of arylsulfatase and β‐glucuronidase in activated sludge: HPLC‐based versus classical spectrophotometric method

“…Recovery experiments were performed by spiking three target compounds with three known concentrations (10, 20, and 40 μM) into activated sludge aqueous, in which the average recovery efficiencies of all the three target compounds ranged from 76.5% to 96.1% with RSD ranged from 1.0%–2.0% (Table 3). In accordance with the requirements of the analytical manual of Japanese Ministry of Land, Infrastructure, Transport, and Tourism for EDCs, recovery efficiency between 50% and 120% with RSD below 20% was regarded as acceptable (Liu et al, 2010b, 2011). Thus, the recovery efficiencies of p NP, p NPS, and p NPG in activated sludge aqueous were satisfactory.…”