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.

Analogy or fallacy, unsafe chemical alternatives: Mechanistic insights into energy metabolism dysfunction induced by Bisphenol analogs in HepG2 cells.

Bisphenol analogs (BPs) are widely used as industrial alternatives for Bisphenol A (BPA). Their toxicity assessment in humans has mainly focused on estrogenic activity, while other toxicity effects and mechanisms resulting from BPs exposure remain unclear. In this study, we investigated the effects of three BPs (Bisphenol AF (BPAF), Bisphenol G (BPG) and Bisphenol PH (BPPH)) on metabolic pathways of HepG2 cells. Results from comprehensive cellular bioenergetics analysis and nontarget metabolomics indicated that the most important process affected by BPs exposure was energy metabolism, as evidenced by reduced mitochondrial function and enhanced glycolysis. Compared to the control group, BPG and BPPH exhibited a consistent pattern of metabolic dysregulation, while BPAF differed from both, such as an increased ATP: ADP ratio (1.29-fold, p < 0.05) observed in BPAF and significantly decreased ATP: ADP ratio for BPG (0.28-fold, p < 0.001) and BPPH (0.45-fold, p < 0.001). Bioassay endpoint analysis revealed BPG/BPPH induced alterations in mitochondrial membrane potential and overproductions of reactive oxygen species. Taken together these data suggested that BPG/BPPH induced oxidative stress and mitochondrial damage in cells results in energy metabolism dysregulation. By contrast, BPAF had no effect on mitochondrial health, but induced a proliferation promoting effect on cells, which might contribute to the energy metabolism dysfunction. Interestingly, BPPH induced the greatest mitochondrial damage among the three BPs but did not exhibit Estrogen receptor alpha (ERα) activating effects. This study characterized the distinct metabolic mechanisms underlying energy metabolism dysregulation induced by different BPs in target human cells, providing new insight into the evaluation of the emerging BPA substitutes.

Non-targeted metabolomics revealing the effects of bisphenol analogues on human liver cancer cells.

Bisphenol analogues (BPs) are widely used in plastics, food packaging and other commercial products as non safer alternative of BPA. As emerging environmental contaminants, BPs have received considerable attention for their adverse effects on human health. However, their effects on liver metabolisms are only marginally understood. In this study, high-resolution mass spectrometry-based global metabolomics and extracellular flux (XF) analysis were applied to characterize the cellular metabolome alterations and reveal the possible mechanisms of the metabolic disorders associated with BPs-induced toxicity in HepG2 cells. BPE, BPB and BPAP with similar chemical structures were selected to compare their interference with different metabolic pathways. A total of 61 key metabolite profiles were significantly altered after exposure to the three BPs. Overall, BPs altered metabolites which are associated with energy metabolism, oxidative stress, cell proliferation and nucleotides synthesis. The primary dysregulated pathways included energy and nucleotides synthesis related Purine and Glycolysis/Gluconeogenesis metabolism. In addition, attenuated mitochondrial function and enhanced glycolysis were found under BPB and BPAP treatment. While attenuated glycolysis was observed under BPE treatment. These findings may provide potential biomarkers indicating the cytotoxicity of BPs and prompt a deeper understanding of the intramolecular metabolic processes induced by BPs exposure.

Evaluation of fireground exposures using urinary PAH metabolites.

BACKGROUND: Firefighters have increased cancer incidence and mortality rates compared to the general population, and are exposed to multiple products of combustion including known and suspected carcinogens. OBJECTIVE: The study objective was to quantify fire response exposures by role and self-reported exposure risks. METHODS: Urinary hydroxylated metabolites of polycyclic aromatic hydrocarbons (PAH-OHs) were measured at baseline and 2-4 h after structural fires and post-fire surveys were collected. RESULTS: Baseline urine samples were collected from 242 firefighters. Of these, 141 responded to at least one of 15 structural fires and provided a post-fire urine. Compared with baseline measurements, the mean fold change of post-fire urinary PAH-OHs increased similarly across roles, including captains (2.05 (95% CI 1.59-2.65)), engineers (2.10 (95% CI 1.47-3.05)), firefighters (2.83 (95% CI 2.14-3.71)), and paramedics (1.84 (95% CI 1.33-2.60)). Interior responses, smoke odor on skin, and lack of recent laundering or changing of hoods were significantly associated with increased post-fire urinary PAH-OHs. SIGNIFICANCE: Ambient smoke from the fire represents an exposure hazard for all individuals on the fireground; engineers and paramedics in particular may not be aware of the extent of their exposure. Post-fire surveys identified specific risks associated with increased exposure.

Exploring the genotoxicity triggers in the MP UV/H2O2-chloramination treatment of bisphenol A through bioassay coupled with non-targeted analysis.

Bisphenol A (BPA) is a well-known xenoestrogen, and UV/H2O2 advanced oxidation process (AOP) is one of the most effective technologies to remove BPA from water. Using BPA spiked tap water, a batch-scale photochemical experiment was conducted to investigate whether BPA can pose a genotoxicity concern during the medium pressure (MP) UV/H2O2 treatment and the post-chloramination. Samples at different UV exposure and post-chloramination durations were collected and analyzed by CALUX® gene reporter assays regarding estrogen receptor α (ERα) and p53 transcriptional activity. MP UV/H2O2 process did not cause extra estrogenic effects from the degradation of BPA, whereas genotoxicity occurred when the treated water was exposed with monochloramine. Seven frequently reported nitrogenous disinfection byproducts (N-DBPs) were detected, but none of them were responsible for the observed genotoxicity. Employed with gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF-MS), four compounds possibly contributed to the genotoxicity were tentatively identified and two of them with aminooxy- or cyano- group were considered as "new" N-DBPs. This study demonstrated that by-products differ from their parent compounds in toxicity can be formed in the UV oxidation with post-disinfection process, which should become a cause for concern.

Bioassay guided analysis coupled with non-target chemical screening in polyethylene plastic shopping bag fragments after exposure to simulated gastric juice of Fish.

In this study, fragments of polyethylene plastic bags were treated with simulated gastric juice of fish for 16 h. Following solid-phase extraction, methanol eluents caused acute toxicity to embryos and larvae of Japanese medaka. Chromatographic fractions (polar to more non-polar with numbers increasing) of the extract were evaluated for toxicity and estrogenic activity using medaka and an estrogen receptor (ER) cell-line. Fractions 6 and 9 had the highest estrogenic effects with relative hydrophobic chemicals. The vtg expression in fraction 6 was 22-fold higher than control, and the ER cellular response in fraction 9 was 8.5-fold higher than controls. Following non-target screening (NTS), several novel phthalates and phenols were identified in the above two fractions. Fractions 1 and 2 appeared to be primarily responsible for the acute toxicity observed with the whole extract. The hatching rate decreased to 36 % in fraction 2, and was not observed following exposure to fraction 1. NTS of these fractions indicated 635 and 808 entities, respectively, most without toxicity information. These results indicate plastic leachates from gastric juices of fish are complex mixtures of many compounds that can have acute reproductive and sublethal endocrine impacts in fish.

Caregiver Psychological Distress: Longitudinal Relationships With Physical Activity and Diet.

Given limited longitudinal research with caregivers (CGs, n = 122) of spouses with Alzheimer disease, and demographically matched noncaregivers (NCGs, n = 117), we compared these groups on psychological distress (anxiety, depression), burden, and health behaviors over 2 years. Analyses examined group differences in relationships of micronutrient recommended daily allowances (RDAs) and physical activity considering hours of care, psychological distress, and burden. Participants were measured and assessed on whether they met micronutrient intake and physical activity totaled over an average week. Regression analyses showed a total effect whereby NCGs had greater increases in meeting micronutrient allowances (RDAs) than CGs (b = 10.91, standard error [SE] = 4.74, 95% confidence interval [CI]: 1.56-20.26). Additionally, over time, NCGs had greater increases in physical activity, which was mediated by hours of care (b = 0.149, SE = 0.060, 95% CI: 0.034-0.270). These results suggest CGs may lack proper nutrients, and care hours may influence their health behaviors.

Occurrence and distribution of pesticides in precipitation as revealed by targeted screening through GC-MS/MS.

Facing the tough challenge of precise measurement of ever-increasing numbers of organic contaminants in the environment, there is an urgent need for more reliable and cost-effective methodologies. In this study, we developed and validated a screening method for analysis of over 450 pesticides in precipitation using gas chromatography with tandem mass spectrometry (GC-MS/MS) in multiple reaction monitoring (MRM) mode. Solid phase extraction (SPE) was applied to extract target analytes from precipitation. Using this targeted approach, we managed to detect 123 pesticides with maximum retention time shifts below 0.1 min (except for DEET) in 101 precipitation samples collected between October 2015 and March 2017 in Singapore. This is probably the first study to report the measurements of a wide range of pesticides in precipitation. A spectrum of insecticides, herbicides, fungicides and their synergists were detected and among them DEET, malathion and carbaryl were the most frequently detected pesticides (detection frequency: 100%, 96% & 67%). The Spearman correlations suggest that some pesticides of different subgroups had significant correlations. It is believed that these finding could shed light on the understanding of the contribution of precipitation to environmental contaminants in water cycle.

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 TUIC20, 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.

Near Real-Time Detection of E. coli in Reclaimed Water.

Advanced treatment of reclaimed water prior to potable reuse normally results in the inactivation of bacterial populations, however, incremental treatment failure can result in bacteria, including pathogens, remaining viable. Therefore, potential microorganisms need to be detected in real-time to preclude potential adverse human health effects. Real-time detection of microbes presents unique problems which are dependent on the water quality of the test water, including parameters such as particulate content and turbidity, and natural organic matter content. In addition, microbes are unusual in that: (i) viability and culturability are not always synonymous; (ii) viability in water can be reduced by osmotic stress; and (iii) bacteria can invoke repair mechanisms in response to UV disinfection resulting in regrowth of bacterial populations. All these issues related to bacteria affect the efficacy of real-time detection for bacteria. Here we evaluate three different sensors suitable for specific water qualities. The sensor A is an on-line, real-time sensor that allows for the continuous monitoring of particulates (including microbial contaminants) using multi-angle-light scattering (MALS) technology. The sensor B is a microbial detection system that uses optical technique, Mie light scattering, for particle sizing and fluorescence emission for viable bacteria detection. The last sensor C was based on adenosine triphosphate (ATP) production. E. coli was used a model organism and out of all tested sensors, we found the sensor C to be the most accurate. It has a great potential as a surrogate parameter for microbial loads in test waters and be useful for process control in treatment trains.

Analysis of haloacetic acids, bromate, and dalapon in natural waters by ion chromatography-tandem mass spectrometry.

The addition of oxidants for disinfecting water can lead to the formation of potentially carcinogenic compounds referred to as disinfection byproducts (DBPs). Haloacetic acids (HAAs) are one of the most widely detected DBPs in US water utilities and some of them are regulated by the US Environmental Protection Agency (USEPA). The present study developed a method to analyze all the compounds in the USEPA method 557 (nine HAAs, bromate and dalapon) plus four potentially more toxic iodinated HAAs in water by coupling ion chromatography with tandem mass spectrometry (IC-MS/MS). This aqueous direct injection method has significant advantages over traditional GC methods, which require a derivatization and sample extraction that are laborious, time-consuming, and can negatively impact reproducibility. The method developed in this study requires half the time of the current USEPA method 557 on IC-MS/MS while including more compounds and achieving sub-µg/L level method detection limits (MDLs) for all 15 target analytes. The single laboratory lowest concentration minimum reporting level (LCMRL) has also been determined in reagent water, which ranged from 0.011 to 0.62µg/L for the analytes. The mean recoveries of the analytes during matrix spike recovery tests were 77-125% in finished drinking water and 81-112% in surface water. This method was then applied to untreated, chlorinated, and chloraminated groundwater and surface water samples. Bromate and 9 HAAs were detected at different levels in some of these samples.

Anticancer properties of baicalein: a review.

The constituents of many traditional Chinese herbal remedies are currently at the forefront of modern cancer research. Baicalein, a bioactive flavone widely used in nutraceuticals and pharmaceuticals, has shown great potential in the treatment and prevention of cancer without causing severe side effects. Baicalein induces cancer cell apoptosis and cause cell cycle arrest. It shows inhibitory effects on angiogenesis, metastasis and inflammation, all of which are necessary for the promotion and progression of cancer. This review presents an overview of the anti-cancer effects and mechanisms of baicalein. In addition, the bioavailability of baicalein and approaches to improve it are summarized. Treatments of baicalein in combination with other anti-cancer agents are also mentioned.

Online solid phase extraction with liquid chromatography-tandem mass spectrometry for determination of estrogens and glucocorticoids in water.

The present work describes the development of a novel fully automated online solid phase extraction (SPE) coupled with high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) using negative electrospray ionisation (ESI) for the simultaneous determination of six estrogens and six glucocorticoids in water. Filtered water samples (5mL) were preconcentrated on a HyperSep™ Retain PEP SPE cartridge, eluted in back-flush mode, and separated on an LC column before analysis by tandem mass spectrometry. The total analysis time for each sample was 17min. Different experimental parameters such as the type of online SPE cartridge, loading flow rate, and composition of methanol in the loading phase were optimised. The intra-day repeatability of method ranged from 1.48 to 9.68% for all analytes, and the inter-day reproducibility ranged from 2.03 to 8.63% for all analytes, except for dexamethasone at 11.95%. These were calculated based on the peak area responses of the targeted analytes spiked at 50ng/L in ultrapure water. The method also showed good linearity from 1 to 100ng/L, with the limits of detection (LODs) ranging from 0.16 to 2.14ng/L. The proposed method was applied to the analysis of municipal wastewater. This fully automated online SPE extraction coupled with LC-MS/MS method is effective and reliable to measure estrogens and glucocorticoids simultaneously due to its high throughput, relatively low solvent consumption, reusability of the online SPE cartridge, and reduction of manual labor.

Biliary Elimination of Pemetrexed Is Dependent on Mrp2 in Rats: Potential Mechanism of Variable Response in Nonalcoholic Steatohepatitis.

Hepatic multidrug resistance-associated protein 2 (MRP2) provides the biliary elimination pathway for many xenobiotics. Disruption of this pathway contributes to retention of these compounds and may ultimately lead to adverse drug reactions. MRP2 mislocalization from the canalicular membrane has been observed in nonalcoholic steatohepatitis (NASH), the late stage of nonalcoholic fatty liver disease, which is characterized by fat accumulation, oxidative stress, inflammation, and fibrosis. MRP2/Mrp2 mislocalization is observed in both human NASH and the rodent methionine and choline-deficient (MCD) diet model, but the extent to which it impacts overall transport capacity of MRP2 is unknown. Pemetrexed is an antifolate chemotherapeutic indicated for non-small cell lung cancer, yet its hepatobiliary elimination pathway has yet to be determined. The purpose of this study was to quantify the loss of Mrp2 function in NASH using an obligate Mrp2 transport substrate. To determine whether pemetrexed is an obligate Mrp2 substrate, its cumulative biliary elimination was compared between wild-type and Mrp2(-/-) rats. No pemetrexed was detected in the bile of Mrp2(-/-) rats, indicating pemetrexed is completely reliant on Mrp2 function for biliary elimination. Comparing the biliary elimination of pemetrexed between MCD and control animals identified a transporter-dependent decrease in biliary excretion of 60% in NASH. This study identifies Mrp2 as the exclusive biliary elimination mechanism for pemetrexed, making it a useful in vivo probe substrate for Mrp2 function, and quantifying the loss of function in NASH. This mechanistic feature may provide useful insight into the impact of NASH on interindividual variability in response to pemetrexed.

Ozonation of Cylindrospermopsin (Cyanotoxin): Degradation Mechanisms and Cytotoxicity Assessments.

Cylindrospermopsin (CYN) is a potent toxic alkaloid produced by a number of cyanobacteria frequently found in lakes and reservoirs used as drinking water sources. We report for the first time detailed pathways for the degradation of CYN by treatment with ozone. This was accomplished by use of ultra-high-performance liquid chromatography (UHPLC)-quadrupole time-of-flight mass spectrometry (QTOF MS), which revealed that CYN is readily degraded by ozone with at least 36 transformation products. Structural similarities among the major products indicated that the carbon-carbon double bond in the uracil ring of CYN was most susceptible to attack by ozone. Furthermore, the nitrogen functionality associated with the tricyclic guanidine moiety is also involved via a degradation pathway that has not been previously observed. To assess the potential toxicity of ozonation products of CYN, the cytotoxicity of CYN and the mixture of its ozonation products was measured in a human hepatoma cell line (HepG2). The IC50 for CYN at 24 and 48 h incubations was approximately 64.1 and 12.5 µM, respectively; however, the ozonation products of CYN did not exhibit measurable cytotoxicity to human cells. The results indicate ozone is an effective and practical method for CYN attenuation in water treatment without formation of overtly toxic transformation products.

Nano-Structured Magnesium Oxide Coated Iron Ore: Its Application to the Remediation of Wastewater Containing Lead.

Magnetically separable nano-structured magnesium oxide coated iron ore (IO(MgO)) was prepared using environmentally benign chemicals, such as iron ore (IO), magnesium(II) nitrate hexahydrate [Mg(NO3)2 x 6H2O] and urea; via an easy and fast preparation method. The lO(MgO) was characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and alternating gradient magnetometer (AGM) analyses. The isotherm and kinetic studies indicated that lO(MgO) has a comparably higher Langmuir constant (K(L), 1.69 L mg(-1)) and maximum sorption capacity (33.9 mg g(-1)) for lead (Pb) than other inorganic media. Based on MgO amount, the removal capacity of Pb by IO(MgO) was 2,724 mg Pb (g MgO)(-1), which was higher than that (1,980 mg g(-1)) for flowerlike magnesium oxide nanostructures reported by Cao et al. The kinetics, FE-SEM, elemental mapping and XRD results revealed that the substitution followed by precipitation was identified as the mechanism of Pb removal and plumbophyllite (Pb2Si4O10 x H2O) was the precipitated phase of Pb. A leaching test revealed that IOMgO) had negligible concentrations of leached Fe at pH 4-9. Since the base material, IO, is cheap and easily available, lO(MgO) could be produced in massive amounts and used for remediation of wastewater containing heavy metals, applying simple and fast magnetic separation.

Interlaboratory comparison of in vitro bioassays for screening of endocrine active chemicals in recycled water.

In vitro bioassays have shown promise as water quality monitoring tools. In this study, four commercially available in vitro bioassays (GeneBLAzer(®) androgen receptor (AR), estrogen receptor-alpha (ER), glucocorticoid receptor (GR) and progesterone receptor (PR) assays) were adapted to screen for endocrine active chemicals in samples from two recycled water plants. The standardized protocols were used in an interlaboratory comparison exercise to evaluate the reproducibility of in vitro bioassay results. Key performance criteria were successfully achieved, including low background response, standardized calibration parameters and high intra-laboratory precision. Only two datasets were excluded due to poor calibration performance. Good interlaboratory reproducibility was observed for GR bioassay, with 16-26% variability among the laboratories. ER and PR bioactivity was measured near the bioassay limit of detection and showed more variability (21-54%), although interlaboratory agreement remained comparable to that of conventional analytical methods. AR bioassay showed no activity for any of the samples analyzed. Our results indicate that ER, GR and PR, were capable of screening for different water quality, i.e., the highest bioactivity was observed in the plant influent, which also contained the highest concentrations of endocrine active chemicals measured by LC-MS/MS. After advanced treatment (e.g., reverse osmosis), bioactivity and target chemical concentrations were both below limits of detection. Comparison of bioassay and chemical equivalent concentrations revealed that targeted chemicals accounted for ≤5% of bioassay activity, suggesting that detection limits by LC-MS/MS for some chemicals were insufficient and/or other bioactive compounds were present in these samples. Our study demonstrated that in vitro bioassays responses were reproducible, and can provide information to complement conventional analytical methods for a more comprehensive water quality assessment.

Increased susceptibility to methotrexate-induced toxicity in nonalcoholic steatohepatitis.

Hepatic drug metabolizing enzymes and transporters play a crucial role in determining the fate of drugs, and alterations in liver function can place individuals at greater risk for adverse drug reactions (ADRs). We have shown that nonalcoholic steatohepatitis (NASH) leads to changes in the expression and localization of enzymes and transporters responsible for the disposition of numerous drugs. The purpose of this study was to determine the effect of NASH on methotrexate (MTX) disposition and the resulting toxicity profile. Sprague Dawley rats were fed either a control or methionine-choline-deficient diet for 8 weeks to induce NASH, then administered a single ip vehicle, 10, 40, or 100 mg/kg MTX injection followed by blood, urine, and feces collection over 96 h with terminal tissue collection. At the onset of dosing, Abcc1-4, Abcb1, and Abcg2 were elevated in NASH livers, whereas Abcc2 and Abcb1 were not properly localized to the membrane, similar to that previously observed in human NASH. NASH rodents receiving 40-100 mg/kg MTX exhibited hepatocellular damage followed by initiation of repair, whereas damage was absent in controls. NASH rodents receiving 100 mg/kg MTX exhibited slightly greater renal toxicity, indicating multiple organ toxicity, despite the majority of the dose being excreted by 6 h. Intestinal toxicity in NASH however, was strikingly less severe than controls, and coincided with reduced fecal MTX excretion. Because MTX-induced gastrointestinal toxicity limits the dose escalation necessary for cancer remission, these data suggest a greater risk for life-threatening MTX-induced hepatic and renal toxicity in NASH in the absence of overt gastrointestinal toxicity.

Ultra high performance liquid chromatography tandem mass spectrometry for rapid analysis of trace organic contaminants in water.

BACKGROUND: The widespread utilization of organic compounds in modern society and their dispersion through wastewater have resulted in extensive contamination of source and drinking waters. The vast majority of these compounds are not regulated in wastewater outfalls or in drinking water while trace amounts of certain compounds can impact aquatic wildlife. Hence it is prudent to monitor these contaminants in water sources until sufficient toxicological data relevant to humans becomes available. A method was developed for the analysis of 36 trace organic contaminants (TOrCs) including pharmaceuticals, pesticides, steroid hormones (androgens, progestins, and glucocorticoids), personal care products and polyfluorinated compounds (PFCs) using a single solid phase extraction (SPE) technique with ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The method was applied to a variety of water matrices to demonstrate method performance and reliability. RESULTS: UHPLC-MS/MS in both positive and negative electrospray ionization (ESI) modes was employed to achieve optimum sensitivity while reducing sample analysis time (<20 min) compared with previously published methods. The detection limits for most compounds was lower than 1.0 picogram on the column while reporting limits in water ranged from 0.1 to 15 ng/L based on the extraction of a 1 L sample and concentration to 1 mL. Recoveries in ultrapure water for most compounds were between 90-110%, while recoveries in surface water and wastewater were in the range of 39-121% and 38-141% respectively. The analytical method was successfully applied to analyze samples across several different water matrices including wastewater, groundwater, surface water and drinking water at different stages of the treatment. Among several compounds detected in wastewater, sucralose and TCPP showed the highest concentrations. CONCLUSION: The proposed method is sensitive, rapid and robust; hence it can be used to analyze a large variety of trace organic compounds in different water matrixes.

Absorption and disposition of bromate in F344 rats.

Bromate (BrO(3)(-)) is a ubiquitous by-product of using ozone to disinfect water containing bromide (Br(-)). The reactivity of BrO(3)(-) with biological reductants suggests that its systemic absorption and distribution to target tissues may display non-linear behavior as doses increase. The intent of this study is to determine the extent to which BrO(3)(-) is systemically bioavailable via oral exposure and broadly identify its pathways of degradation. In vitro experiments of BrO(3)(-) degradation in rat blood indicate a rapid initial degradation immediately upon addition that is >98% complete at concentrations up to 66µM in blood. As initial concentrations are increased, progressively lower fractions are lost prior to the first measurement. Secondary to this initial loss, a slower and predictable first order degradation rate was observed (10%/min). Losses during both phases were accompanied by increases in Br(-) concentrations indicating that the loss of BrO(3)(-) was due to its reduction. In vivo experiments were conducted using doses of BrO(3)(-) ranging from 0.077 to 15.3mg/kg, administered intravenously (IV) or orally (gavage) to female F344 rats. The variable nature and uncertain source of background concentrations of BrO(3)(-) limited derivation of terminal half-lives, but the initial half-life was approximately 10min for all dose groups. The area under the curve (AUC) and peak concentrations (C(t=5')) were linearly related to IV dose up to 0.77mg/kg; however, disproportionate increases in the AUC and C(t=5') and a large decrease in the volume of distribution was observed when IV doses of 1.9 and 3.8mg/kg were administered. The average terminal half-life of BrO(3)(-) from oral administration was 37min, but this was influenced by background levels of BrO(3)(-) at lower doses. With oral doses, the AUC and C(max) increased linearly with dose up to 15.3mgBrO(3)(-)/kg. BrO(3)(-) appeared to be 19-25% bioavailable without an obvious dose-dependency between 0.077 and 1.9mg/kg. The urinary elimination of BrO(3)(-) and Br(-) was measured from female F344 rats for four days following administration of single doses of 8.1mgKBrO(3)/kg and for 15 days after a single dose of 5.0mgKBr/kg. BrO(3)(-) elimination was detected over the first 12h, but Br(-) elimination from BrO(3)(-) over the first 48h was 18% lower than expected based on that eliminated from an equimolar dose of Br(-) (15.5±1.6 vs. 18.8±1.2µmol/kg, respectively). The cumulative excretion of Br(-) from KBr vs. KBrO(3) was equivalent 72h after administration. The recovery of unchanged administered BrO(3)(-) in the urine ranged between 6.0 and 11.3% (creatinine corrected) on the 27th day of treatment with concentrations of KBrO(3) of 15, 60, and 400mg/L of drinking water. The recovery of total urinary bromine as Br(-)+BrO(3)(-) ranged between 61 and 88%. An increase in the fraction of the daily BrO(3)(-) dose recovered in the urine was observed at the high dose to both sexes. The deficit in total bromine recovery raises the possibility that some brominated biochemicals may be produced in vivo and more slowly metabolized and eliminated. This was supported by measurements of dose-dependent increases of total organic bromine (TOBr) that was eliminated in the urine. The role these organic by-products play in BrO(3)(-)-induced cancer remains to be established.