High-Throughput Transcriptomics of Water Extracts Detects Reductions in Biological Activity with Water Treatment Processes

The presence of numerous chemical contaminants from industrial, agricultural, and pharmaceutical sources in water supplies poses a potential risk to human and ecological health. Current chemical analyses suffer from limitations, including chemical coverage and high cost, and broad-coverage in vitro assays such as transcriptomics may further improve water quality monitoring by assessing a large range of possible effects. Here, we used high-throughput transcriptomics to assess the activity induced by field-derived water extracts in MCF7 breast carcinoma cells. Wastewater and surface water extracts induced the largest changes in expression among cell proliferation-related genes and neurological, estrogenic, and antibiotic pathways, whereas drinking and reclaimed water extracts that underwent advanced treatment showed substantially reduced bioactivity on both gene and pathway levels. Importantly, reclaimed water extracts induced fewer changes in gene expression than laboratory blanks, which reinforces previous conclusions based on targeted assays and improves confidence in bioassay-based monitoring of water quality.

Adsorption kinetics of 20 glucocorticoids at environmentally relevant concentrations in wastewater by powdered activated carbons and development of surrogate models

Glucocorticoids (GCs) are widely used in the treatment of the coronavirus disease of 2019 (COVID-19), and the toxicity of GCs to aquatic organisms has aroused widespread concern. Powdered activated carbon (PAC) has proven effective in removing various trace organic pollutants. In this study, the adsorption behaviors of 20 typical GCs onto PACs were investigated at environmentally relevant concentrations (ng/L) in real wastewater, using four commercially available PACs (HDB, WPH, 20BF, PWA). The results showed that PAC adsorption was feasible for GC removal at ng/L concentrations. After adsorption for 60 min, the GC removal efficiencies obtained by HDB, WPH, 20BF, and PWA were 90-98 %, 89-97 %, 84-96 %, and 71-90 %, respectively. The adsorption processes of 20 GCs on PACs were well fitted by the pseudo-second-order kinetics model (with R ² >0.98). Among the four PACs, HDB achieved the highest rates because of the electrostatic attraction between HDB (positively charged) and the complex of GCs and natural organic matter (GC-NOM, negatively charged). Among the 20 GCs, compounds with substitutions of halogen atoms or five-membered rings at C-17 achieved higher adsorption rates because of the enhanced formation of hydrogen bonds and a resulting increase in electron density. In addition, surrogate models with total fluorescence (TF) and ultraviolet absorbance at 254 nm (UV₂₅₄) were developed to monitor the attenuation trend of GCs during adsorption processes. Compared with the UV₂₅₄ model, the TF model showed better sensitivity to GC monitoring, which could greatly simplify the water quality monitoring process and facilitate online monitoring of GCs in water.

Fully-automated SPE coupled to UHPLC-MS/MS method for multiresidue analysis of 26 trace antibiotics in environmental waters: SPE optimization and method validation

Achieving simultaneous determination of antibiotic multiresidues in environmental waters by solid phase extraction (SPE) coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) with detection limits ≤ ng L^-1 is still a huge challenge. Moreover, the offline SPE procedure was performed manually, costly, and time-consuming, while the online SPE required precision pretreatment instruments that require highly-skilled personnel. In this paper, a fully automated SPE coupled with UHPLC-MS/MS method was developed for analysis of antibiotics (sulfonamides, quinolones, and macrolides) in water matrices. Sample preparation optimization included SPE materials and configuration (HLB disks), sample volume (500-1000 mL), and pH (pH = 3) with a flow rate at 2~5 mL min^-1, and an elution procedure with 2 × 6 mL methanol, and 2 × 6 mL acetone. Meanwhile, the parameters for UHPLC-MS/S detection of analytes were optimized, including LC retention time, and MS parameters. The instrumental limits of detection (LOD) and quantification (LOQ) of analytes ranged from 0.01-0.72 μg L^-1 and 0.05-2.39 μg L^-1, respectively, with satisfactory linear calibration (R² > 0.995) and precision (< 9.9%). Recoveries in spike samples ranged between 77.5-104.9% in pure water, 59.4-97.8% in surface water (SW), and 58.2-108.6% in wastewater effluent (WWE) with relative standard deviations ≤ 12.8%. The matrix effects observed for most analytes were suppression (0-28.1%) except for five analytes having presented enhancement (0-14.6 %) in SW or WWE. This method can basically meet the needs of trace antibiotic residues detection in waters, with examples of concentrations of detected antibiotics being lower than LOQ (LLQ) -94.47 ng L^-1 in WWEs and LLQ-15.47 ng L^-1 in SW in the lower reaches of the Yangtze River Basin.

Developmental assays using invasive cane toads, Rhinella marina, reveal safety concerns of a common formulation of the rice herbicide, butachlor

Identifying the adverse impacts of pesticide exposure is essential to guide regulations that are protective of wildlife and human health. Within rice ecosystems, amphibians are valuable indicators because pesticide applications coincide with sensitive reproductive and developmental life stages. We conducted two experiments using wild cane toads (Rhinella marina) to test 1) whether environmentally relevant exposure to a commercial formulation of butachlor, an acetanilide herbicide used extensively in rice, affects amphibian development and 2) whether cane toad tadpoles are capable of acclimatizing to sub-lethal exposure. First, we exposed wild cane toads to 0.002, 0.02, or 0.2 mg/L of butachlor (Machete EC), during distinct development stages (as eggs and hatchlings, as tadpoles, or continuously) for 12 days. Next, we exposed a subset of animals from the first experiment to a second, lethal concentration and examined survivorship. We found that cane toads exposed to butachlor developed slower and weighed less than controls, and that development of the thyroid gland was affected: exposed individuals had smaller thyroid glands and thyrocyte cells, and more individual follicles. Analyses of the transcriptome revealed that butachlor exposure resulted in downregulation of transcripts related to metabolic processes, anatomic structure development, immune system function, and response to stress. Last, we observed evidence of acclimatization, where animals exposed to butachlor early in life performed better than naïve animals during a second exposure. Our findings indicate that the commercial formulation of butachlor, Machete EC, causes thyroid endocrine disruption in vertebrates, and suggest that exposure in lowland irrigated rice fields presents a concern for wildlife and human health. Furthermore, we establish that developmental assays with cane toads can be used to screen for adverse effects of pesticides in rice fields.

Magnetic ion-exchange (MIEX) resin for perfluorinated alkylsubstance (PFAS) removal in groundwater: Roles of atomic charges for adsorption

In this study, magnetic ion exchange (MIEX) resin was evaluated to remove six carboxylic and three sulfonic PFAS at environmentally relevant concentrations (∼300 ng/L) in groundwater with low organic content and aromaticity (0.78 mg/L of dissolved organic carbon, DOC and 0.96 L mg^-1m^-1 of specific UV absorbance, SUVA). In order to evaluate PFAS adsorption, the apparent equilibrium constant for PFAS adsorption in a dilute system was derived as an indicator of the adsorption capacity of MIEX. In adsorption of PFAS, hydrophobic interactions induced by difluoromethylene and trifluoromethyl groups are known to be effective. However, the hydrophobic and charge interactions caused by such functional groups are not easily differentiable from each other since both are additive with respect to the chain length. In this study, the total negative atomic charge [∑Q_i(-)] was calculated using density functional theory (DFT) calculation and correlated with the apparent equilibrium constants. The negative atomic charge showed better correlation than the hydrophobicity (log D_ow at pH 7) of PFAS, suggesting that the charge interaction would be a more plausible role of fluorinated moieties for adsorption in the MIEX process than the hydrophobic interaction. This was also bolstered by the similar adsorption kinetics and equilibrium of PFOS (log D_ow = 3.05) and its less hydrophobic isomer (log D_ow = 2.79), but with almost identical total negative atomic charge (8.05 and 8.06 of ∑Q_i(-), respectively). The regeneration efficiency of MIEX was also assessed. Almost complete restoration of PFAS adsorption capacity was achieved after 30 min of a regeneration process with a 10% w/w NaCl solution as a regenerant. The efficient regeneration was attributed to the effective desorption of dissolved organic matter that occupied sorptive sites predominantly.

A direct injection liquid chromatography tandem mass spectrometry method for the kinetic study on iodinated contrast media (ICMs) removal in natural water

Iodinated contrast media (ICMs) are a class of X-ray contrast media worldwide utilized for radiographic procedures. Since they cannot be removed efficiently during water treatment, they can be found in surface and groundwater. In this work, a rapid and sensitive direct injection liquid chromatography-tandem (LC-MS/MS) method for the simultaneous analysis of seven ICMs media (iopamidol, ioxitalamic acid, diatrizoic acid, iothalamic acid, iohexol, iomeprol and iopromide) in complex aqueous matrices has been developed and validated. The MDLs for the analytes ranged from 0.7 to 21 ng L^-1 in ultrapure water, and recoveries ranged from 86 to 100% in drinking water, 85-103% in groundwater and 84-105% in WWTP effluent. A stereo-isomer for iopromide was separated. This analytic method was applied to investigate the removal of target ICMs by low pressure ultra violet light (LPUV) advanced oxidation processes with three oxidants, hydrogen peroxide, free chlorine and monochloramine in groundwater. Results showed that the addition of oxidants did not enhance attenuation of ICMs, since fluence-based decay apparent rate constants were similar (K_UV = 3.2 × 10^-3, K_UV-Cl2 = 3.6 × 10^-3 and K_UV-NH2 = 3.4 × 10^-3 10^-3 cm² mJ^-1). This yielded direct photolysis is the main mechanism to attenuate target ICMs.

Inhibition of anaerobic ammonium oxidation (anammox) bacteria by addition of high and low concentrations of chloramphenicol and comparison of attached- and suspended-growth

Inhibition of anammox activities was tested with two ranges of chloramphenicol (CAP) concentration (5, 10, 20, 50, and 100 mg L^-1) and (100, 500, and 1000 μg L^-1). In a short-term study, strong inhibition of activity was dependent of CAP concentration in both attached-growth (SBR-A) and suspended-growth (SBR-S) systems. The activities of attached-growth cultures at all CAP concentrations were reversible after 1 day, while activities for suspended-growth cultures were only gradually reversible dependent on the CAP concentrations. In long-term studies with daily additions of 6 mg L^-1 CAP, the anammox activity on day 41 in SBR-A had decreased to 18% baseline (SAA reduced from 0.528 to 0.096 mg N mg^-1 VSS d^-1). More rapid reduction of anammox activity was observed in SBR-S, down to 17% baseline after only 27 days (SAA decreased from 0.576 to 0.096 mg N mg^-1 VSS d^-1). Inhibition was irreversible in both SBR-S and SBR-A after the long-term study. With lower CAP additions (100-1000 μg L^-1), the activities in both reactors were stable during daily CAP addition for two weeks. Attached-growth cultures tended to be more tolerant of CAP addition than suspended-growth cultures. Both un-competitive and non-competitive models could be used to compare anammox activities with the higher CAP concentrations. The SAA_max [fx] (the maximum specific anammox activity) and _hK_i (the inhibition constant) of SBR-A were 0.48 mg N mg^-1 VSS d^-1 and 98.3 mg L^-1, respectively. The SAA_max[fx] and K_i of SBR-S were 1.25 mg N mg^-1 VSS d^-1and 71.1 mg L^-1, respectively.

Attenuation of pharmaceutically active compounds in aqueous solution by UV/CaO2 process: Influencing factors, degradation mechanism and pathways

As freshwater sources continue to be influenced by wastewater effluents, there is a dire need to develop advanced water treatment processes capable of treating the wastewater-derived contaminants, especially for pharmaceutically active compounds (PhACs). Ultraviolet light (UV) combined with calcium peroxide (CaO₂) as an advanced oxidation process (AOP) to attenuate five widespread PhACs (carbamazepine (CBZ), primidone (PMD), phenobarbital (PBB), thiamphenicol (TAP) and florfenicol (FF)) was investigated in this paper. The degradation of these compounds followed pseudo-first-order kinetics (R² > 0.96). The optimum CaO₂ dosage was 0.1 g L^-1 and lower initial contaminants concentration was beneficial to their degradation. The UV/CaO₂ treatment of test PhACs was attributed to the combination of UV/H₂O₂ and UV-base-photolysis (UV/Ca(OH)₂), and the degradation mechanism was recognized as both UV direct photolysis and indirect photolysis caused by reactive radicals (•OH, triplet states of dissolved organic matter (³DOM*), and ¹O₂). Furthermore, the tentative transformation pathways of the five PhACs were proposed based on the detected intermediates and the degradation mechanisms. The final products of inorganic carbon and nitrogen indicate UV/CaO₂ treatment can significantly mineralize test PhACs. Also, the CaO₂ addition significantly reduced the energy consumption of UV irradiation according to electrical energy per order. The effective removal of CBZ and PMD in a secondary wastewater effluent by UV/CaO₂ treatment demonstrates the potential use of this AOP technology in advanced treatment of wastewater-derived PhACs.

Downstream trends of in vitro bioassay responses in a wastewater effluent-dominated river

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_IC20, 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.

Epigenetics of breast cancer: Modifying role of environmental and bioactive food compounds

SCOPE

Reduced expression of tumor suppressor genes (TSG) increases the susceptibility to breast cancer. However, only a small percentage of breast tumors is related to family history and mutational inactivation of TSG. Epigenetics refers to non-mutational events that alter gene expression. Endocrine disruptors found in foods and drinking water may disrupt epigenetically hormonal regulation and increase breast cancer risk. This review centers on the working hypothesis that agonists of the aromatic hydrocarbon receptor (AHR), bisphenol A (BPA), and arsenic compounds, induce in TSG epigenetic signatures that mirror those often seen in sporadic breast tumors. Conversely, it is hypothesized that bioactive food components that target epigenetic mechanisms protect against sporadic breast cancer induced by these disruptors.

METHODS AND RESULTS

This review highlights (i) overlaps between epigenetic signatures placed in TSG by AHR-ligands, BPA, and arsenic with epigenetic alterations associated with sporadic breast tumorigenesis; and (ii) potential opportunities for the prevention of sporadic breast cancer with food components that target the epigenetic machinery.

CONCLUSIONS

Characterizing the overlap between epigenetic signatures elicited in TSG by endocrine disruptors with those observed in sporadic breast tumors may afford new strategies for breast cancer prevention with specific bioactive food components or diet.

Predicting trace organic compound attenuation by ozone oxidation: Development of indicator and surrogate models

Ozone oxidation has been demonstrated to be an effective treatment process for the attenuation of trace organic compounds (TOrCs); however, predicting TOrC attenuation by ozone processes is challenging in wastewaters. Since ozone is rapidly consumed, determining the exposure times of ozone and hydroxyl radical proves to be difficult. As direct potable reuse schemes continue to gain traction, there is an increasing need for the development of real-time monitoring strategies for TOrC abatement in ozone oxidation processes. Hence, this study is primarily aimed at developing indicator and surrogate models for the prediction of TOrC attenuation by ozone oxidation. To this end, the second-order kinetic equations with a second-phase R_ct value (ratio of hydroxyl radical exposure to molecular ozone exposure) were used to calculate comparative kinetics of TOrC attenuation and the reduction of indicator and spectroscopic surrogate parameters, including UV absorbance at 254 nm (UVA₂₅₄) and total fluorescence (TF). The developed indicator model using meprobamate as an indicator compound and the surrogate models with UVA₂₅₄ and TF exhibited good predictive power for the attenuation of 13 kinetically distinct TOrCs in five filtered and unfiltered wastewater effluents (R² values > 0.8). This study is intended to help provide a guideline for the implementation of indicator/surrogate models for real-time monitoring of TOrC abatement with ozone processes and integrate them into a regulatory framework in water reuse.

Interactions between a small chronic increase in diel water temperature and exposure to a common environmental contaminant on development of Arizona tiger salamander larvae

Global climate change leading to increased temperatures may affect shifts in physiological processes especially in ectothermic organisms. Temperature-dependent shifts in developmental rate in particular, may lead to life-long changes in adult morphology and physiology. Combined with anthropogenic changes in the chemical environment, changes in developmental outcomes may affect adult functionality. The purpose of this study is to determine 1) if small increases in diel water temperature affect the development of Arizona tiger salamander (Ambystoma tigrinum nebulosum) larvae, and 2) if this change interacts with exposure to the common environmental thyroid disrupting compound, perchlorate. Larvae between Watson and Russell developmental stages 8-13 were exposed to ammonium perchlorate (AP) at doses of 0, 20 or 200ppb and then raised at either ambient or a 0.9°C elevated above ambient temperature for 81days in outdoor enclosures. During the first 5 treatment weeks, AP treatment induced slower development and smaller snout-vent length (SVL) of exposed larvae, but only in the elevated temperature group. During the later stages of development, the small increase in temperature, regardless of AP treatment, tended to decrease the time to metamorphosis and resulted in a significantly smaller body mass and worse body condition. Our results suggest that even small diel water temperature increases can affect the developmental process of salamanders and this shift in the water temperature may interact with a common environmental contaminant.

Balancing the Budget: Accounting for Glucocorticoid Bioactivity and Fate during Water Treatment

Numerous studies have identified the presence and bioactivity of glucocorticoid receptor (GR) active substances in water; however, the identification and activity-balance of GR compounds remained elusive. This study determined the occurrence and attenuation of GR bioactivity and closed the balance by determining those substances responsible. The observed in vitro GR activity ranged from 39 to 155 ng dexamethasone-equivalent/L (ng Dex-EQ/L) in the secondary effluents of four wastewater treatment plants. Monochromatic ultraviolet light of 80 mJ/cm(2) disinfection dose was efficient for GR activity photolysis, whereas chlorination could not appreciably attenuate the observed GR activity. Ozonation was effective only at relatively high dose (ozone/TOC 1:1). Microfiltration membranes were not efficient for GR activity attenuation; however, reverse osmosis removed GR activity to levels below the limits of detection. A high-sensitivity liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was then developed to screen 27 GR agonists. Twelve were identified and quantified in effluents at summed concentrations of 9.6-21.2 ng/L. The summed Dex-EQ of individual compounds based on their measured concentrations was in excellent agreement with the Dex-EQ obtained from bioassay, which demonstrated that the detected glucocorticoids can entirely explain the observed GR bioactivity. Four synthetic glucocorticoids (triamcinolone acetonide, fluocinolone acetonide, clobetasol propionate, and fluticasone propionate) predominantly accounted for GR activity. These data represent the first known publication where a complete activity balance has been determined for GR agonists in an aquatic environment.