A year-long passive sampling of phenolic endocrine disrupting chemicals in the East River, South China

Assessment of developmental toxicity and the potential mode of action underlying single and binary exposure to estrogenic endocrine disrupting chemicals in zebrafish (Danio rerio)

The current study investigated the effect of single and binary exposure to distinct xenoestrogens, including diethylstilbestrol (DES) and zearalenone (ZEN), on zebrafish embryos subjected to continuous exposure for 4 days starting from 4 h post fertilization. Noteworthy impact on cumulative mortality, hatchability, spinal and tail curvature, pericardial edema, and reduction in blood circulation were observed in DES-treated embryos, with lower incidence and intensity shown for ZEN at the same nominal concentration (3 μM). An interactive effect was seen for the combined exposure to DES and ZEN, in which deformities and circulatory failure mediated by DES were mitigated by co-treatment with low concentrations of ZEN. Similarly, ZEN-induced spinal and tail curvature, pericardial edema, and blood flow reduction declined dramatically following DES co-exposure at low concentrations. A significant counteracting effect has been observed against DES- and ZEN-induced developmental anomalies following co-treatment with an estrogen receptor (ER) antagonist, fulvestrant (FUL). The assessment of the aromatase gene (CYP19A1b) showed that DES strongly upregulated mRNA expression of CYP19A1b with a lower EC50 (1.1 × 10-3 nM) than a natural estrogen, 17β-estradiol (2.5 nM). Similarly, ZEN induced CYP19A1b mRNA expression with an EC50 of 57 nM. Exposure to 10 or 20 μM FUL inhibited the expression of CYP19A1b induced by a single treatment of DES or ZEN. Overall, the competitive action against ER could be the main mechanism underlying the developmental toxicity induced by DES and ZEN.

Occurrence and distribution of PPCPs in water from two largest urban lakes of China: First perspective from DGT in-situ measurement

Pharmaceutical and personal care products (PPCPs) are an important group of emerging contaminants that may threaten organisms at trace concentrations. However, research on the occurrence of PPCPs in urban lakes in China is still scarce. In this study, 15 PPCPs in the Tangxun Lake and the Donghu Lake were collected using the diffusive gradients in thin-films (DGT) technique and analyzed by high performance liquid chromatography tandem-mass spectrometry (HPLC-MS/MS). Thirteen of the 15 targeted PPCPs were detected in the Tangxun Lake, and all PPCPs were detected in the Donghu Lake, with total concentrations ranging from 160 to 730 ng/L (average: 401 ng/L) and 187 to 1933 ng/L (average: 653 ng/L), respectively. Bisphenol A (BPA) was the dominant PPCP, followed by disinfectants in both lakes. The total concentrations of PPCPs in the Donghu Lake were higher than those in the Tangxun Lake. The spatial distribution characteristics of PPCPs in the two lakes were different, with higher total concentrations in the eastern part than in the western part of the Tangxun Lake spatially and higher in the north-western part than in the south-eastern part of the Donghu Lake. The results of the risk assessment showed that BPA and estrone posed high risks to the aquatic environment (RQ ≥ 1), while triclosan and estriol presented a medium risk (0.1 ≤ RQ < 1) in some sites. This study was the first attempt to apply DGT for providing vital data on the evaluation of the ecological risk of PPCPs in the two largest lakes in China, and attention should be paid to the long-term ecological effects caused by the occurrence of PPCPs in lakes.

Passive Sampling: A Greener Technique for the 'Dual Carbon' Goal While Implementing the Action Plan for Controlling Emerging Pollutants

In response to global climate change, China recently committed to achieving peak carbon emissions by 2030 and carbon neutrality by 2060. Carbon emission reduction should be considered in every sector of society including environmental monitoring. As an energy-saving technique in environmental monitoring, passive sampling has many advantages, such as in-situ sampling and a reduction in time/labour requirements. This perspective illustrates the "greenness" of passive sampling techniques, by comparison with traditional sampling methods, and its potential contribution to the 'dual carbon' goal. At the same time passive sampling can provide key support for the action plan for controlling emerging pollutants in China.

Diffusive gradients in thin films (DGT) probe for effectively sampling of per- and polyfluoroalkyl substances in waters and sediments

The passive sampling technique, diffusive gradients in thin films (DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per- and polyfluoroalkyl substances (PFAS). However, its effectiveness has been questioned because of the small effective sampling area (3.1 cm²). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area (27 cm²) and as a result lower method quantification limits (0.15 - 0.21 ng/L for one-day deployment and 0.02 - 0.03 ng/L for one-week deployment) and much higher (by > 10 factors) sampling rate (100 mL/day) compared to the standard DGT (piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling (500 mL). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.

Development and applications of diffusive gradients in thin films for monitoring pharmaceuticals in surface waters

Pharmaceutical contaminants in surface water have raised significant concerns because of their potential ecological risks. In particular, coronavirus disease 2019 (COVID-19)-related pharmaceuticals can be released to surface water and reduce environmental water quality. Therefore, reliable and robust sampling tools are required for monitoring pharmaceuticals. In this study, passive sampling devices of diffusive gradients in thin films (DGTs) were developed for sampling 35 pharmaceuticals in surface waters. The results demonstrated that hydrophilic-lipophilic balance (HLB) was more suitable for DGT-based devices compared with XAD18 and XDA1 resins. For most pharmaceuticals, the performance of the HLB-DGT devices were independent of pH (5.0-9.0), ionic strength (0.001-0.5 M), and flow velocity (0-400 rpm). The HLB-DGT devices exhibited linear pharmaceutical accumulation for 7 days, and time-weighted average concentrations provided by the HLB-DGT were comparable to those measured by conventional grab sampling. Compared to previous studies, we extended DGT monitoring to include three antiviral drugs used for COVID-19 treatment, which may inspire further exploration on identifying the effects of COVID-19 on ecological and human health.

Assessment of the contamination by 2,4,6-tribromophenol of marine waters and organisms exposed to chlorination discharges

2,4,6-tribromophenol (TBP) is implied in the production of brominated flame retardants but is also a major chlorination by-product in seawater. A growing number of studies indicate that TBP is highly toxic to the marine biota, but the contribution of anthropogenic sources among natural production is still under question concerning its bioaccumulation in marine organisms. Here, several water sampling campaigns were carried out in the industrialized Gulf of Fos (northwestern Mediterranean Sea, France) and clearly showed the predominant incidence of industrial chlorination discharges on the TBP levels in water, at the 1-10 ng L^-1 level in average and reaching up to 580 ng L^-1 near the outlets. The bioaccumulation of TBP was measured in 90 biota samples from the Gulf of Fos. The concentrations found in European conger muscle tissues (140-1000 ng g^-1 lipid weight, in average), purple sea urchin gonads (830-880 ng g^-1 lipid weight, in average), and Mediterranean mussel body (1500-2000 ng g^-1 lipid weight, in average) were above all published references. Significant correlations with fish length (European conger) and gonad somatic index (purple sea urchin) were also identified. Comparatively, fish, urchins and mussels from other Mediterranean sites analyzed within this study showed a lower bioaccumulation level of TBP, consistently with what found elsewhere. Industrial outflows were thus identified as hotspots for TBP in seawater and marine organisms. The environmental risk assessment indicated a high potential toxicity in the industrial Gulf of Fos, in particular near the outlets, and a limited threat to human but toxicological references are lacking.

Passive sampling hydrophilic and hydrophobic bisphenol analogues using hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane in surface waters

Bisphenol analogues (BPs) are ubiquitous emerging contaminants in water environments and have wide polarity ranges (1.65 < log K_ow < 7.2). Integrated passive sampling strategy rarely contains hydrophilic and hydrophobic organics simultaneously, while the method has good application perspective in monitoring organic contaminants. This work evaluated passive sampling performance for fifteen BPs in a newly developed passive sampler, i.e., hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane (HECAM). In the dynamic accumulation experiments, both hydrophilic and hydrophobic BPs (including moderately hydrophilic BPs) well followed first-order kinetic uptake in the HECAMs. The estimated uptake rate constants, elimination rate constants, and equilibrium partition coefficients for BPs ranged from 4.4 L g^-1 d^-1 to 14.7 L g^-1 d^-1, 0.22 d^-1 to 0.72 d^-1, and 3.99 to 4.64, respectively. The kinetic parameters for BPs in HECAM show limited correlations to log K_ow values, which the rule differs from traditional passive sampler. In the study of elimination kinetics, three deuterium labeled compounds showed incomplete elimination in HECAM and did not follow first-order isotropic exchange kinetics. Dual sorption mechanisms including both adsorption and partition were found for chemicals in HECAM, which the partitioned part could release to water and the adsorbed part could not easily release to water from HECAM. As a result, performance reference compounds (PRCs) calibration may be inapplicable to HLB sorbent-based passive sampler. The field deployment of HECAM in coastal waters of Guangdong, China resulted in the detection of eleven BPs, which indicated that the waters have been polluted by various BPs. Finally, monitoring strategy of simultaneous passive sampling hydrophobic and hydrophilic organic contaminants in surface waters was recommended.

Suspect, non-target and target screening of pharmaceuticals and personal care products (PPCPs) in a drinking water system

Drinking water quality and safety are very important in protecting human health. Chemical contaminants in drinking water system have become an increasing concern. Our knowledge about what chemicals are present in drinking water is still limited. Here we screened chemicals of emerging concern in a conventional drinking water system based on suspect, non-target screening and target analysis, and assessed their variations in different seasons and different treatment units. Overall, 720 chemicals were identified with HRMS databases from the suspect and non-target screening and 48 chemicals in five categories were further confirmed with the high confidence level, with predominance of pharmaceuticals and personal care products (PPCPs) and pesticides. Four compounds are newly found in aquatic environment with no literature or chemical occurrence data record. Temporal variations and variable removals were observed for these chemicals in the system. Target analysis of 110 PPCPs showed detection of 21, 19 and 22 compounds in the drinking water treatment plant with a concentration range of 0.11-844 ng/L in the three seasons, but only 8, 9 and 15 compounds detected in tap water (0.16-32.5 ng/L). The variations of the detected chemicals were less obvious in tap water, with most having concentrations below 2 ng/L. The results indicated efficient removal for most PPCPs in the drinking water system. The findings from this study demonstrated the strong capability of combined non-target screening and target analysis in identifying and assessing various organic chemicals in drinking water system.

Development and field evaluation of the organic-diffusive gradients in thin-films (o-DGT) passive water sampler for microcystins

The presence of microcystins (MCs) in waterbodies requires a simple and reliable monitoring technique to characterize better their spatiotemporal distribution and ecological risks. An organic-diffusive gradients in thin films (o-DGT) passive sampler based on polyacrylamide diffusive gel and hydrophilic-lipophilic balance (HLB) binding gel was developed for MCs in water. The mass accumulation of three MCs (MC-LR, -RR, and -YR) was linear over 10 days (R² ≥ 0.98). Sampling rates (2.68-3.22 mL d^-1) and diffusion coefficients (0.90-1.08 × 10^-6 cm² s^-1) of three MCs were obtained at 20 °C. Two different passive samplers, o-DGT and the Solid Phase Adsorption Toxin Tracking device (SPATT), were co-deployed to estimate MC levels at three lakes in California, USA. Measured total MC concentrations were up to 10.9 μg L^-1, with MC-LR the primary variant at a measured maximum concentration of 2.74 μg L^-1. Time-weighted average MC concentrations by o-DGT were lower than grab water samples, probably because grab sampling measures both dissolved and particulate phases (i.e., MCs in cyanobacteria). Passive water samplers by design can only measure dissolved-phase MCs, which are considerably less during the cyanobacteria-laden periods observed. Both o-DGT and grab samples gave comparable results for three MC variants at low levels of MCs, e.g., <0.1 μg L^-1. o-DGT showed a higher correlation with grab sampling than SPATT did. This study demonstrates that o-DGT can be effectively used for monitoring and evaluation of dissolved MCs in waters.

Accumulation and passive sampling of bisphenol analogues using triolein-embedded cellulose acetate membrane in waters

Bisphenol analogues (BPs) are emerging contaminants that have been widely detected in water environments. The presence of substituted hydrophilic and hydrophobic groups in the molecule may lead to unclear performance in passive sampling. This study tested the accumulation capacity and passive sampling of fifteen BPs in a triolein-embedded cellulose acetate membrane (TECAM) passive sampler. In a dynamic accumulation experiment, twelve hydrophobic BPs accumulated in the TECAM with concentrations ranging from 251 ng g^-1 to 6283 ng g^-1, and three hydrophilic BPs did not accumulate during the 72 h exposure duration. BPs accumulations were determined by the hydrophilic and hydrophobic substituent groups in molecule structures. The estimated passive sampling parameters showed correlations to both the log K_ow values and chemical structures, and compared to other contaminants, such as organophosphorus flame retardants. Environmental factors, including flow rate, temperature, salinity, and pH, that affect the accumulation of BPs in the TECAM were tested, and the flow rate was found to be an important factor affecting the uptake rate. The isotropic exchange kinetics for BPs in the TECAM were verified, and the results indicated that BPs can be calibrated with performance reference compounds (PRCs) in field applications. Finally, a field deployment of TECAM in river waters successfully estimated the time-weighted concentrations of two hydrophobic BPs. To address the inherent weaknesses of TECAM in sampling hydrophilic and moderately hydrophobic BPs, future studies should explore alternative passive samplers, such as hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membranes, to sample BPs in surface waters.

Removal efficiencies and risk assessment of endocrine-disrupting chemicals at two wastewater treatment plants in South China

Endocrine-disrupting chemicals (EDCs) in the effluent from wastewater treatment plants (WWTPs) are an important pollutant sources of the aquatic system. In this study, the removal efficiencies of eight typical EDCs at two domestic WWTPs in Dongguan City, China, are reported based on instrumental analysis and bioassay results. Bioactivities, including steroidogenesis-disrupting effects, estrogen receptor (ER)-binding activity, and aryl hydrocarbon receptor (AhR)-binding activity were evaluated using the H295R, MVLN, and H4IIE cell bioassays, respectively. The potential environmental risks of these residual EDCs were also evaluated. The results of instrumental analysis showed that nonylphenol was the major chemical type present among the eight tested EDCs. Meanwhile, concentrations of estrogen compounds including estrone, 17β-estradiol (E2), estriol, 17α-ethinyl estradiol, and diethylstilbestrol were relatively low. The removal rates of all eight EDCs were relatively high. Although the chemical analysis indicated high removal efficiency, the bioassay results showed that steroidogenesis-disrupting effects as well as ER-binding and AhR-binding activities remained, with E2-equivalent values of effluent samples ranging from 0.16 to 0.9 ng·L^-1, and 2,3,7,8-tetrachlorodibenzo-p-dioxin-equivalent values ranging from 0.61 to 4.09 ng L^-1. Principal component analysis combined with regression analysis suggests that the chemicals analyzed in this study were partly responsible for these ER and AhR activities. Ecological risk assessment of the residual EDCs showed that estrone was the most hazardous chemical among the eight EDCs tested, with a risk quotient of 1.44-5.50. Overall, this study suggests that, despite high apparent removal efficiencies of typical EDCs, their bioactivities and potential ecological risks cannot be ignored.

In situ measurement of an emerging persistent, mobile and toxic (PMT) substance - Melamine and related triazines in waters by diffusive gradient in thin-films

Melamine has received increasing public attention as a persistent, mobile and toxic (PMT) substance. To better assess environmental exposure and risks of melamine and related triazines (cyromazine, ammeline, and atrazine), a new passive sampling method based on the diffusive gradients in thin films (DGT) technique has been developed and validated in this study. The studied triazines were adsorbed quickly and strongly by the selected mixed cation exchange (MCX) binding gels. This MCX-DGT can linearly accumulate these chemicals over at least 5 days, with neither significant individual influence from pH (6-8), ionic strength (0.01-0.5 M) or dissolved organic matter (0-10 M), or interaction effects. Field applications in Southern China showed that DGT performed well in both sewage treatment plant (STP) and river samples. Melamine was found to be the dominant triazine with the concentrations at μg·L^-1 in the STP and receiving river. Surprisingly, much higher concentration of melanine was found in the STP effluent than influent, and appeared to be some of the highest concentrations reported in STPs worldwide to date. Comparable melamine and atrazine concentraions in the STP effluent and receiving river suggested other sources to the river. The MCX-DGT sampler developed here was demonstrated to be reliable and robust for measuring the triazines in waters, and is promising as an in situ tool in understanding the occurrence, sources, and fate of the emerging PMT substances in aquatic environment.

Development of an efficient remediation system with a low cost after identification of water pollutants including phenolic compounds in a tannery built-up area in Bangladesh

Water pollution caused by tannery wastewater is an important issue in developing countries. Most studies have focused on inorganic chemicals represented by chromium as a tannery-related main pollutant. This is the first study in which pollution of water by tannery-related organic chemicals was assessed by a combination of qualitative and quantitative analyses. Our quantitative analysis showed that the maximum concentration of total phenolic compounds (phenols), consisting of phenol, bisphenol F, p-cresol and chlorocresol, in canal water in a tannery built-up area in Bangladesh was >67-fold higher than the Environmental, Health and Safety (EHS) guideline value. Mapping of our results indicated tanneries as the sources of phenols pollution. Our original depurative, a hydrotalcite-like compound consisting of magnesium and iron (MF-HT), could adsorb all kinds of phenols and exhibited the highest phenol adsorption ability (115.8 mg/g) among reported hydrotalcite-like compounds. The levels of phenols in canal water samples were reduced to levels below the guideline value by using MF-HT with assistance of a photocatalytic reaction. Moreover, the mean level of chromium (112.2 mg/L) in canal water samples was decreased by 99.7% by using the depurative. Thus, the depurative has the potential for solving the problem of tannery-related water pollution by phenols and chromium.

Tetrafluoroterephthalonitrile-crosslinked β-cyclodextrin polymer as a binding agent of diffusive gradients in thin-films for sampling endocrine disrupting chemicals in water

β-Cyclodextrin (β-CD) is an inexpensive and reproducible material derived from corn starch. It is possible that tetrafluoroterephthalonitrile-crosslinked β-cyclodextrin polymer (TFN-CD), a cheap but efficient adsorbent, could be a suitable binding agent for use in the passive sampling technique, diffusive gradients in thin-films (DGT). Herein, the TFN-CD binding gel was prepared and then evaluated as the binding phase of DGT to sample six endocrine disrupting chemicals (EDCs) in water. The TFN-CD dispersed uniformly in the binding gel due to its hydrophilicity. The quantitative recoveries (99.3%-106%) of EDCs from the TFN-CD binding gel could be conveniently achieved by ultrasonic extraction using 5 mL methanol for 10 min. Compared with the excellent HLB (hydrophilic-lipophilic-balanced resin) binding gel, the TFN-CD binding gel had comparable or even faster adsorption kinetics, although the equilibrium adsorption capacity was slightly lower. The effective adsorption capacities of TFN-CD-based DGT (TFN-CD-DGT) were roughly estimated to enable a 7-days deployment in EDC solution of 25.7-30.0 μg L^-1. Studies of influencing factors showed that the ionic strength (0-0.5 M), pH (3.73-9.13), dissolved organic matter (0-20 mg L^-1) and long-term storage (204 days) had negligible influence on the performance of TFN-CD-DGT. Finally, the TFN-CD-DGT was successfully used to record sudden increases in bulk concentrations during simulated discharge events in pond water. These results demonstrate that TFN-CD is a suitable binding agent for sampling of EDCs, and the low cost of TFN-CD could be conducive to the application of DGT in large-scale sampling.

Development and application of diffusive gradients in thin-films for in situ sampling of the bitterest chemical - denatonium benzoate in waters

Denatonium benzoate (DB), a commonly used bitter agent in numerous products, has recently been recognized as a waterborne contaminant due to concern about its potential persistence, mobility and toxicity (PMT). However, its occurrence, levels and fate in global aquatic environments are largely unknown. In this study, a new sampling method, based on diffusive gradients in thin films (DGT) with mixed-mode cation exchange (MCX) as the binding agent, was developed for measuring DB in waters. MCX shows a rapid adsorption and high capacity for DB. DB is linearly accumulated by MCX-DGT. pH (6-8), ionic strength (0.01-0.5 M), or DOM (0-10 M) do not show any significant effect on the MCX-DGT performance, confirming its reliability. The DGT measurements in a wastewater treatment plant (WWTP) are comparable to those by paralleled grab sampling. The field results suggest DB is persistent in WWTPs and could be a potential domestic wastewater indicator. Therefore, MCX-DGT is a promising technique for understanding the environmental occurrence, levels and fate of DB. This is a first report of using DGT for DB monitoring and of DB occurrence in Chinese environments. Further exploration of DGT as a reliable passive monitoring tool for a wide range of PMT substances in different applications is warranted.

Preparation of a Novel Resin Based Covalent Framework Material and Its Application in the Determination of Phenolic Endocrine Disruptors in Beverages by SPE-HPLC

A new type of economical covalent organic framework material(COF), namely resin based covalent organic framework material, was prepared by combining resin and covalent organic framework material by hydrothermal synthesis, which was based on the preparation of traditional COF material(TpBD COF). The properties of the material and covalent organic framework material were compared in the way of characterization, and the possible reaction mechanism was analyzed. The solid phase extraction separation (SPE) ability of this material for four kinds of phenolic endocrine disrupting compounds (bisphenol F, bisphenol A, octylphenol and nonylphenol) in beverage samples was investigated. The results showed that the prepared COF materials had abundant internal channels, ordered structure, large specific surface area (TpBD COF: 814.6 m2/g and resin based COF: 623.9 m2/g) and good thermal stability (pyrolysis temperature was 443 °C and 437 °C, respectively). Solid phase extraction experiments demonstrated that the two COF materials as adsorbent of solid phase extraction column had ideal adsorption separation effect and good anti-interference ability, and had strong anti-interference ability. The SPE effect was superior to the traditional solid phase extraction column. The precision RSD of this method was less than 3%. This SPE method had high recovery and could be reused (carbonated beverage: 98.18-102.18% and beverage: 98.52-101.79%), In addition, the recovery of the material did not change significantly in the 50 cycles of solid phase extraction, indicating that the material had good stability and could be reused, which could meet the requirements for the detection and analysis of trace pollutants in environmental samples. The resin based COF material prepared in this study could reduce the cost of monomer uses and provide a possibility for its industrial production. At the same time, as an efficient SPE adsorbent, it also provided a new research scheme for the enrichment of trace phenolic endocrine disruptors in beverage samples.

Non-conventional water reuse in agriculture: A circular water economy

Due to the growing and diverse demands on water supply, exploitation of non-conventional sources of water has received much attention. Since water consumption for irrigation is the major contributor to total water withdrawal, the utilization of non-conventional sources of water for the purpose of irrigation is critical to assuring the sustainability of water resources. Although numerous studies have been conducted to evaluate and manage non-conventional water sources, little research has reviewed the suitability of available water technologies for improving water quality, so that water reclaimed from non-conventional supplies could be an alternative water resource for irrigation. This article provides a systematic overview of all aspects of regulation, technology and management to enable the innovative technology, thereby promoting and facilitating the reuse of non-conventional water. The study first reviews the requirements for water quantity and quality (i.e., physical, chemical, and biological parameters) for agricultural irrigation. Five candidate sources of non-conventional water were evaluated in terms of quantity and quality, namely rainfall/stormwater runoff, industrial cooling water, hydraulic fracturing wastewater, process wastewater, and domestic sewage. Water quality issues, such as suspended solids, biochemical/chemical oxygen demand, total dissolved solids, total nitrogen, bacteria, and emerging contaminates, were assessed. Available technologies for improving the quality of non-conventional water were comprehensively investigated. The potential risks to plants, human health, and the environment posed by non-conventional water reuse for irrigation are also discussed. Lastly, three priority research directions, including efficient collection of non-conventional water, design of fit-for-purpose treatment, and deployment of energy-efficient processes, were proposed to provide guidance on the potential for future research.