Estimated human excretion rates of natural estrogens calculated from their concentrations in raw municipal wastewater and its application

Deconjugation potentials of natural estrogen conjugates in sewage and wastewater treatment plant: New insights from model prediction and on-site investigations

Natural estrogen conjugates play important roles in municipal wastewater treatment plant (WWTP), but their deconjugation potentials are poorly understood. This work is the first to investigate the relationships between the enzyme activities of arylsulfatase/β-glucuronidase and deconjugation potentials of natural estrogen conjugates. This work led to three important findings. First, the enzyme activity of β-glucuronidase in sewage is far higher than that of arylsulfatase, while their corresponding activities in activated sludge were similar. Second, a model based on β-glucuronidase could successfully predict the deconjugation potentials of natural estrogen glucuronide conjugates in sewage. Third, the enzyme activity of arylsulfatase in sewage was too low to lead to evident deconjugation of sulfate conjugates, which means that the deconjugation rate of estrogen sulfates can be regarded as zero. By comparing their theoretical removal based on enzyme activity and on-site investigation, it is reasonable to conclude that reverse deconjugation of estrogen conjugates (i.e., conjugation of natural estrogens to form conjugated estrogens) likely exist in WWTP, which explains well why natural estrogen conjugates cannot be effectively removed in WWTP. Meanwhile, this work provides new insights how to improve the removal performance of WWTP on natural estrogen conjugates. SYNOPSIS: This work is the first to show how arylsulfatase/β-glucuronidase could affect deconjugation of natural estrogen conjugates and possible way to enhance their removal in wastewater treatment plant.

Twelve natural estrogens in urines of six threatened or endangered mammalian species in Zoo Park: implications and their potential risk

This work was the first to report twelve natural estrogens (NEs) in the urines of six threatened or endangered mammalians in a Zoo Park of Guangzhou (i.e., panda, gorilla, elephant, African lion, jaguar, and leopard). Ten out of twelve NEs were detected at least in one urine sample of the six mammalians studied, including the four major NEs (i.e., estrone (E1), 17β-estradiol (E2), 17α-estradiol (αE2), estriol (E3)), and six other NEs (i.e., 4-hydroxyestrone (4OHE1), 2-hydroxyestradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 16α-hydroxyestrone (16α-OHE1), 16ketoestradiol (16ketoE2), and 17epiestriol (17epiE3)). The six studied mammalians, ranked in the order of high to low urinary concentration of total NEs, were jaguar, African lion, gorilla, elephant, panda, and leopard, with respective urinary concentrations of 110.4, 86.4, 71.4, 66.0, 55.9, and 52.8 ng/mL. According to the average urinary concentration of NE in the six mammalians ranked from high to low, the top five NEs detected were 16α-OHE1, 4OHE1, E1, E3, and 17epiE3, respectively. These clearly indicated the occurrence of NEs other than the four major types in urines of animals in a Zoo Park. Moreover, the daily excretion rates of the five detected NEs by one elephant ranged from 1162-2254 μg/d with a total daily excretion rate of 8260 μg/d, suggesting that the total urinary excretion of NEs by one adult elephant was equivalent to that by 170 premenopausal women or 506 adult men. Consequently, it appears from this study that NEs in the urines of zoo animals should be considered an emerging source of NEs.

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

Arylsulfatase and β-glucuronidase are two important enzymes in wastewater and surface water, which play important roles on cleavage of sulfate/glucuronide estrogens. In this work, a high-performance liquid chromatography (HPLC)-based new method was firstly established for arylsulfatase/β-glucuronidase with determination of p-nitrophenyl sulfate (pNPS)/p-nitrophenyl-β-D-glucuronide (pNPG). The limits of detections (LODs) of the developed method for pNPS and pNPG were 0.164 and 0.098 μM, respectively. Intraday and interday reproducibility expressed as relative standard deviation (RSD) values of retention times and peak areas was 0.39%-3.68% and 0.23%-4.74%, respectively. The respective recovery efficiencies of this HPLC-based method spiking at three different concentrations for p-nitrophenol (pNP), pNPS, and pNPG in activated sludge were 76.5%-88.1%, 79.2%-93.1%, and 84.2%-96.1%, with RSD below 3.9%. The HPLC-based method was finally applied to estimate the enzyme activity of arylsulfatase/β-glucuronidase in one activated sludge system and along which the classical spectrophotometric method was also evaluated. Compared with the classic spectrophotometric analytical method, the HPLC-based new method could simultaneously measure arylsulfatase/β-glucuronidase one time, which was convenient and time-saving. Moreover, the developed method could effectively avoid possible underestimation that the spectrophotometric method might encounter. PRACTITIONER POINTS: A new HPLC-based method for activity estimation of arylsulfatase and β-glucuronidase was developed. The HPLC-based method can simultaneously estimate enzyme activity of both arylsulfatase and β-glucuronidase. The HPLC-based method can avoid possible underestimation that spectrophotometric method may encounter.

Twelve natural estrogens in urines of swine and cattle: Concentration profiles and importance of eight less-studied

Although four major natural estrogens (i.e., estrone (E1), 17β-estradiol (E2), estriol (E3) and 17α-estradiol (αE2)) have been commonly found in livestock urine, this study reports the occurrence of eight other less-studied natural estrogens in urine of swine and cattle, i.e. 2-hydroxyestone (2OHE1), 4-hydroxyestrone (4OHE1), 2-hydroxyestradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 16-epiestriol (16epiE3), 16α-hydroxyestrone (16αE1), 16-ketoestradiol (16ketoE2), and 17epiestriol (17epiE3). Results showed that each estrogen was found in at least one urine sample, and 6 of 8 the less-studied estrogens were present at frequencies of ≥90% in boars, ≥70% in sows, and ≥50% in dairy cattle. Five of eight the less-studied estrogens were present at frequencies of ≥33.3% in four beef cattle and one bull. On a concentration basis, the 8 less-studied natural estrogens represented 73.2%, 85.2%, 39.9%, 47.7%, 26.9%, 56.0% and 44.1% of total concentrations of the twelve natural estrogens when combining data from all animals. Similar results were observed based on estrogen equivalence, which indicated these newly detected eight less-studied natural estrogens were not negligible. This work is the first to figure out the importance of these less-studied natural estrogens in livestock urine, and their potential environmental risks associated with discharge of livestock wastewater should be urgently assessed in a holistic manner.

Strategy for effective inhibition of arylsulfatase/β-glucuronidase to prevent deconjugation of sulfate and glucuronide conjugates in wastewater during sample collection and storage

Arylsulfatase and β-glucuronidase are two important enzymes that are responsible for deconjugation of estrogen conjugates. It is important to keep estrogen conjugates intact during sample collection and storage, while the effective inhibition conditions for arylsulfatase and β-glucuronidase remain unknown. To elucidate these conditions, inhibition experiments were performed by adding several inhibitors or by introducing extreme pH conditions. This work confirms that arylsulfatase and β-glucuronidase can tolerate some extremes, including high concentrations of mercury dichloride, ethanol, and EDTA, while low pH (<3) or high pH (>11) can effectively inhibit their activities. The high tolerance of arylsulfatase and β-glucuronidase for mercury dichloride explains why estrogen conjugates in wastewater samples were deconjugated, even in the extremely unfavorable condition with a high concentration of mercury dichloride. Although low pH (<3) can effectively inhibit arylsulfatase/β-glucuronidase, deconjugation of sulfate conjugates by acid hydrolysis readily occurs; thus, a high pH of 11 is an appropriate storage condition for the effective inhibition of arylsulfatase/β-glucuronidase. This appropriate storage condition was confirmed and validated with diluted and sterilized activated sludge samples in which arylsulfatase/β-glucuronidase inhibition was effective for 48 h at room temperature and with a high pH of 11. The developed appropriate storage condition for effective inhibition of arylsulfatase/β-glucuronidase has wide application potential not only for estrogen conjugates but also for all conjugates of other organic micropollutants.

Human exposure of bisphenol A and its analogues: understandings from human urinary excretion data and wastewater-based epidemiology

This work evaluated human exposure to bisphenol A (BPA) and its analogues based on human urinary excretion data and wastewater-based epidemiology (WBE). The results showed that the world's average human daily intake ranked from high to low is in order of bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS), bisphenol P (BPP), bisphenol AP (BPAP), bisphenol B (BPB), bisphenol Z (BPZ), and bisphenol AF (BPAF), and their corresponding human daily intakes are 2.53, 0.68, 0.60, 0.41, 0.36, 0.29, 0.24, and 0.06 μg/p/day, respectively. BPA is clearly the dominant bisphenol for human exposure. However, the results also showed that humans have been widely exposed to BPA analogues as well. Many BPA analogues showed similar estrogenic activities to those of BPA; therefore, the adverse effects of BPA and its analogues on humans should be comprehensively evaluated. The nominal exposure levels obtained based on wastewater-based epidemiology ranked high to low are in order of BPA (513.73 μg/p/day), BPF (10.20 μg/p/day), BPS (5.21 μg/p/day), BPP (1.15 μg/p/day), BPZ (0.66 μg/p/day), BPB (0.61 μg/p/day), BPAF (0.58 μg/p/day), and BPAP (0.35 μg/p/day). The world's human average daily intakes of BPA and its analogues are only 0.5-47.9% of the intakes of their corresponding human nominal exposures. This study suggests that other sources rather human excretions are important origins in municipal wastewater, which indicates that the WBE method based on parent compounds is inappropriate for evaluations of human daily intakes of BPA and its analogues, neither for other industrial compounds that have multiple important sources. Three main important sources of BPA and its analogues in municipal wastewater are likely effluents of industrial wastewater, discharges of hospital wastewater, and landfill leachates. To decrease discharges of BPA and its analogues to the natural environment, any mixing of industrial and hospital wastewater as well as landfill leachates in municipal wastewater is not favorable.

Occurrence, sorption, and transformation of free and conjugated natural steroid estrogens in the environment

Natural steroid estrogens (NSEs), including free estrogens (FEs) and conjugated estrogens (CEs), are of emerging concern globally among public and scientific community due to their recognized adverse effects on human and wildlife endocrine systems in recent years. In this review, the properties, occurrence, sorption process, and transformation pathways of NSEs are clarified in the environment. The work comprehensively summarizes the occurrence of both free and conjugated estrogens in different natural and built environments (e.g., river, WWTPs, CAFOs, soil, and sediment). The sorption process of NSEs can be impacted by organic compounds, colloids, composition of clay minerals, specific surface area (SSA), cation exchange capacity (CEC), and pH value. The degradation and transformation of free and conjugated estrogens in the environment primarily involves oxidation, reduction, deconjugation, and esterification reactions. Elaboration about the major, subordinate, and minor transformation pathways of both biotic and abiotic processes among NSEs is highlighted. The moiety types and binding sites also would affect deconjugation degree and preferential transformation pathways of CEs. Notably, some intermediate products of NSEs still remain estrogenic potency during transformation process; the elimination of total estrogenic activity needs to be addressed in further studies. The in-depth researches regarding the behavior of both free and conjugated estrogens are further required to tackle their contamination problem in the ecosystem. Graphical abstract ᅟ.

Trace determination of sulfonamide antibiotics and their acetylated metabolites via SPE-LC-MS/MS in wastewater and insights from their occurrence in a municipal wastewater treatment plant

Antibiotics have drawn much attention as their wide usage in humans and animals may result in microbial resistance, which is a huge threat to humans' health. Studies on the occurrence and removals of antibiotics in wastewater treatment plants have been widely performed, but very few covered their main acetylated metabolites. This study developed an effective analytical method for the trace determination of four sulfonamides and three acetylated metabolites in municipal wastewaters, which was validated by linearity (R² > 0.995), sensitivity (limit of quantification, LOQ < 0.78 ng/L), recovery (77.7%-148.1%) and precision (relative standard deviation, RSD < 9.6%). All sulfonamides and their acetylated metabolites were detected in municipal wastewaters including influent, primary settling tank and effluent. Removal performances of sulfapyridine (SP), sulfadiazine (SDZ), sulfamethoxazole (SMZ), and N₄-acetyl sulfadiazine (AC-SDZ) in the municipal wastewater treatment plant were moderate or excellent, whereas the corresponding removals of sulfamethazine (SM2), N₄-acetyl sulfapyridine (AC-SP), and N₄-acetyl sulfamethazine (AC-SM2) were poor. The calculated poor removal of SM2 might be attributed to its fluctuation in raw wastewater, whereas the poor removals of AC-SP and AC-SM2 may be due to re-transformation from their parent sulfonamides. Our results showed that monitoring of acetylated sulfonamides in municipal wastewater is important for two reasons. One is that acetylated metabolites are good biomarkers for wastewater-based epidemiology when they are combined with their corresponding parent sulfonamides. The other is that the potential risk of sulfonamides in effluent to the natural environment cannot be accurately evaluated unless their acetylated metabolites are also accounted. This report is the first to address the potential risk of acetylated sulfonamides in effluent of wastewater treatment plants.

Fast trace determination of nine odorant and estrogenic chloro- and bromo-phenolic compounds in real water samples through automated solid-phase extraction coupled with liquid chromatography tandem mass spectrometry

A fast and reliable method was developed for simultaneous trace determination of nine odorous and estrogenic chloro- and bromo-phenolic compounds (CPs and BPs) in water samples using solid-phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS). For sample preparation, the extraction efficiencies of two widely applied cartridges Oasis HLB and Sep-Pak C18 were compared, and the Oasis HLB cartridge showed much better extraction performance; pH of water sample also plays important role on extraction, and pH = 2-3 was found to be most appropriate. For separation of the target compounds, small addition of ammonium hydroxide can obviously improve the detection sensitivity, and the optimized addition concentration was determined as 0.2%. The developed efficient method was validated and showed excellent linearity (R ² > 0.995), low limit of detection (LOD, 1.9-6.2 ng/L), and good recovery efficiencies of 57-95% in surface and tap water with low relative standard deviation (RSD, 1.3-17.4%). The developed method was finally applied to one tap and one surface water samples and most of these nine targets were detected, but all of them were below their odor thresholds, and their estrogen equivalent (EEQ) were also very low.

Worldwide human daily intakes of bisphenol A (BPA) estimated from global urinary concentration data (2000-2016) and its risk analysis

To evaluate BPA's potential risk to health, it is important to know human daily intake. This study describes a simple but effective method to estimate the levels of human BPA intake among four different populations based on urinary concentration data. Nationally, of the 30 countries examined, the top ten countries for adult intake were Italy, Sweden, Denmark, France, Cyprus, Australia, Israel, Ghana, Jamaica, and Belgium. When the urinary excretion sample size was large enough and over 1000, it was found that the national estimated BPA daily intakes in the child group among countries, showed a good linear relationship with those of their corresponding adult group. Except the infant group with limited data, the global estimated BPA daily intakes for children and pregnant women were 2 and 1.4 times that of the adult group. Although the national and global estimated BPA daily intakes were generally below the temporary tolerable daily intake (tTDI) recommended by the European Food Safety Authority (EFSA), but some normal individuals' daily intakes exceeded the tTDI.

Levels of six antibiotics used in China estimated by means of wastewater-based epidemiology

Due to lack of proper regulation, information about antibiotics consumption in many countries such as China is difficult to obtain. In this study, a simple method based on wastewater-based epidemiology was adopted to estimate their usage in four megacities of China. Six antibiotics (norfloxacin, ofloxacin, sulfamethoxazole, trimethoprim, erythromycin and roxithromycin), which are the most frequently consumed antibiotics in China, were selected as the targets. Based on our results, Chongqing had the largest total annual consumption of the selected six antibiotics among the four megacities, followed by Guangzhou, then Hong Kong, with Beijing having the least, with values of 4.4 g/y/P, 4.0 g/y/P, 1.6 g/y/P, and 1.3 g/y/P, respectively. Compared with the daily consumption per capita in Italy, the estimated consumption levels of the selected six antibiotics in four cities of China were 12-41 times those of Italy. Our results suggested that the consumption of antibiotics in China was excessive.

Removal of natural estrogens and their conjugates in municipal wastewater treatment plants: a critical review

This article reviews studies focusing on the removal performance of natural estrogens in municipal wastewater treatment plants (WWTPs). Key factors influencing removal include: sludge retention time (SRT), aeration, temperature, mixed liquor suspended solids (MLSS), and substrate concentration. Batch studies show that natural estrogens should biodegrade well; however, batch observations do not always agree with observations from full-scale municipal WWTPs. To explain this discrepancy, deconjugation kinetics of estrogen conjugates in lab-scale studies were examined and compared. Most estrogen conjugates with slow deconjugation rates are unlikely to be easily removed; others could be cleaved in WWTP settings. Nevertheless, some estrogens cleaved from their conjugates may be found in treated effluent, because deconjugation requires several hours or longer, and there is insufficient rest time for the biodegradation of the cleaved natural estrogens in the WWTP. Therefore, WWTP removals of natural estrogens are likely to be underestimated when estrogen conjugates are present in raw wastewater. This review suggests that biodeconjugation of estrogen conjugates should be enhanced to more effectively remove natural estrogens in WWTPs.