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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 vitroassays 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.

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.

Liquid crystal monomers (LCMs) are a large family of artificial ingredients that have been widely used in global liquid crystal display (LCD) industries. As a major constituent in LCDs as well as the end products of e-waste dismantling, LCMs are of growing research interest with regard to their environmental occurrences and biochemical consequences. Many studies have analyzed LCMs in multiple environmental matrices, yet limited research has investigated the toxic effects upon exposure to them. In this study, we combined in silicosimulation and in vitroassay validation along with omics integration analysis to achieve a comprehensive toxicity elucidation as well as a systematic mechanism interpretation of LCMs for the first time. Briefly, the high-throughput virtual screen and reporter gene assay revealed that peroxisome proliferator-activated receptor gamma (PPARγ) was significantly antagonized by certain LCMs. Besides, LCMs induced global metabolome and transcriptome dysregulation in HK2 cells. Notably, fatty acid β-oxidation was conspicuously dysregulated, which might be mediated through multiple pathways (IL-17, TNF, and NF-kB), whereas the activation of AMPK and ligand-dependent PPARγ antagonism may play particularly important parts. This study illustrated LCMs as a potential PPARγ antagonist and explored their toxicological mode of action on the trans-omics level, which provided an insightful overview in future chemical risk assessment.

The integration of advanced oxidation processes (AOPs) with membrane technology offers benefits for catalyst recovery and reducing membrane fouling. However, the application of the hybrid process could be hampered by the background species in water matrix. This study addresses this challenge by developing catalytic ceramic membranes (CCMs) with dual mechanisms to intensify acetaminophen (ACT) removal in water. The CCMs effectively activated peroxymonosulfate (PMS), achieving ACT degradation of 85 % and 93 % in real water matrices (reverse osmosis retentate and settled water, respectively) and 99 % in MQ water. The CCMs demonstrated consistent performance across multiple operational cycles, even in the presence of humic acid (HA) (96 % ACT reduction). The CCM design features Co3O4catalytic layer on CCM surface, facilitating surface oxidation, reducing fouling, and TiO2intermediate rejection layers serving as barrier for bulk organic pollutants, achieving 50 % HA removal through rejection and 70 % with 1.5 mM PMS. This design facilitates catalytic degradation at the membrane surface, allowing retention and degradation of bulk organic pollutants and intermediates, while ACT permeates into CCM substrate. The surface oxidation and rejection enhanced confinement oxidation within the Co3O4-coated macropores, minimizing interference from background species. LC-QTOF analysis identified multiple degradation pathways, including hydroxylation, acetyl-amino group cleavage, side chain oxidation and benzene ring cleavage, with intermediates showing reduced toxicity. Reactive oxygen species involved in the system were identified and PMS activation mechanism was proposed. This research highlights the potential of the hybrid process, enhancing micropollutant removal by mitigating interference from background species, providing practical implications in water treatment applications.

Increasing chemical pollution of aquatic environments is a growing concern with global relevance. A large number of organic chemicals are termed as “micropollutants” due to their low concentrations, and long-term exposure to micropollutants may pose considerable risks to aquatic organisms and human health. In recent decades, numerous treatment methods and technologies have been proposed to remove micropollutants in water, and typically several micropollutants were chosen as target pollutants to evaluate removal efficiencies. However, it is often unclear whether their toxicity and occurrence levels and frequencies enable them to contribute significantly to the overall chemical pollution in global aquatic environments. This review intends to answer an important lingering question: Which micropollutants or class of micropollutants deserve more attention globally and should be removed with higher priority? Different risk-based prioritization approaches were used to address this question. The risk quotient (RQ) method was found to be a feasible approach to prioritize micropollutants in a large scale due to its relatively simple assessment procedure and extensive use. A total of 83 prioritization case studies using the RQ method in the past decade were compiled, and 473 compounds that were selected by screening 3466 compounds of three broad classes (pharmaceuticals and personal care products (PPCPs), pesticides, and industrial chemicals) were found to have risks (RQ > 0.01). To determine the micropollutants of global importance, we propose an overall risk surrogate, that is, the weighted average risk quotient (WARQ). The WARQ integrates the risk intensity and frequency of micropollutants in global aquatic environments to achieve a more comprehensive priority determination. Through metadata analysis, we recommend a ranked list of 53 micropollutants, including 36 PPCPs (e.g., sulfamethoxazole and ibuprofen), seven pesticides (e.g., heptachlor and diazinon), and 10 industrial chemicals (e.g., perfluorooctanesulfonic acid and 4-nonylphenol) for risk management and remediation efforts. One caveat is that the ranked list of global importance does not consider transformation products of micropollutants (including disinfection byproducts) and new forms of pollutants (including antibiotic resistance genes and microplastics), and this list of global importance may not be directly applicable to a specific region or country. Also, it needs mentioning that there might be no best answer toward this question, and hopefully this review can act as a small step toward a better answer.

As a class of endocrine disrupting compounds (EDCs), corticosteroids (CSs) have attracted increasing attention due to their large excretion masses and toxic effects. However, compared to the very well-studied estrogens and androgens, few studies have been made dealing with the removal of CSs at environmentally relevant concentrations using advanced water and wastewater treatment processes. In this study, degradation performances of 26 natural and synthetic CSs in secondary effluent at environmentally relevant concentrations were comparatively investigated during UV/free chlorine (UV/Cl2), UV/monochloramine (UV/NH2Cl) and UV/hydrogen peroxide (UV/H2O2) treatments. The 26 CSs could be divided into two groups: UV sensitive CSs, which have two double bonds in ring A (Δ1,4), and UV insensitive CSs, which have only one double bond in ring A (Δ4). The UV sensitive CSs could be effectively removed (removal efficiency >60%) by a UV dose of 100 mJ cm−2while the UV insensitive CSs could be removed (removal efficiency >40%) by a UV dose of 800 mJ cm−2. The removal efficiencies of UV insensitive CSs increased with the increase of UV dose. Most of the CSs were poorly removed by sole Cl2, NH2Cl, or H2O2treatment (removal efficiency <40%). However, the addition of Cl2, NH2Cl, and H2O2promoted the UV degradation of CSs, especially for UV-insensitive CSs. UV photolysis would be the predominant mechanism in the UV/Cl2, UV/NH2Cl, and UV/H2O2processes for removing CSs in water. Besides the UV photolysis, HO radicals also functioned for CS removal. Compared with the insignificant effects of reactive chlorine species (RCS), the reactive nitrogen species (RNS) showed obvious selectivity in CS degradation. This study expanded the UV induced oxidation performances of CSs, which lays a foundation for exploring degradation mechanisms and eliminating the pollution from CSs.

Needless to say, the safety of treated water for potable reuse must be definitively ensured. Numerous methods are available for assessing water quality; it's important to understand their challenges and limitations.

An Fe3O4-impregnated catalytic ceramic membrane (CCM) was fabricated through a facile ethylene glycol-gel-assisted wet impregnation method. Ethylene glycol played a dual role, acting as a reducing agent for iron (III) nitrate salt and a chelating agent to disperse catalyst uniformly in the CCM. The resulting 5xFe3O4-CCM efficiently activated peroxymonosulfate (PMS) to generate reactive oxygen species (ROS), achieving a 99% removal of atrazine (ATZ) within a short hydraulic retention time (HRT) of 5.7s. This was facilitated by the spatial confinement effect in CCMs, enhancing the interaction among ATZ, ROS and CCM. The versatile 5xFe3O4-CCM could also effectively activate H2O2and peroxydisulfate (PDS). It demonstrated robustness in real wastewater matrices (settled water and RO-reject) collected from local water reclamation and treatment plants. The 5xFe3O4-CCM exhibited self-cleaning properties in reducing fouling of CCM by humic acid. ROS scavenging experiments and electron paramagnetic resonance (EPR) spectroscopy revealed the pivotal role of SO4•-, •OH, and 1O2in ATZ removal. The co-existing anion species HCO3-showed a strong inhibitory effect on ATZ degradation compared to other ionic species (NO3-and Cl-), attributed to different scavenging reaction rate of both SO4•-and •OH by anions in generating less reactive species. Possible degradation pathways of 5xFe3O4-CCM/PMS were proposed based on the LC-QTOF analysis, including oxidation, dealkylation, dealkylation-hydroxylation, dechlorination-hydroxylation of both s-triazine ring and side chain. The toxicity of the ATZ by-products was assessed, revealing reduced toxicity after treatment. With optimized operating parameters, Fe3O4-CCM can be utilized effectively in different advanced oxidation processes (AOPs) and real wastewater matrices.

Ordering takeout is a growing social phenomenon and may raise public health concerns. However, the associated health risk of compounds leaching from plastic packaging is unknown due to the lack of chemical and toxicity data. In this study, 20 chemical candidates were tentatively identified in the environmentally relevant leachate from plastic containers through the nontargeted chemical analysis. Three main components with high responses and/or predicted toxicity were further verified and quantified, namely, 3,5-di-tert-butyl-4-hydroxycinnamic acid (BHC), 2,4-di-tert-butylphenol (2,4-DTBP), and 9-octadecenamide (oleamide). The toxicity to zebrafish larvae of BHC, a degradation product of a widely used antioxidant Irganox 1010, was quite similar to that of the whole plastic leachate. In the same manner, RNA-seq-based ingenuity analysis showed that the affected canonical pathways of zebrafish larvae were quite comparable between BHC and the whole plastic leachate, i.e., highly relevant to neurological disease, metabolic disease, and even behavioral disorder. Longer-term exposure (35 days) did not cause any effect on adult zebrafish but led to decreased hatching rate and obvious neurotoxicity in zebrafish offspring. Collectively, this study strongly suggests that plastic containers can leach out a suite of compounds causing non-negligible impacts on the early stages of fish via direct or parental exposure.

Reverse osmosis (RO)-based desalination and advanced water purification facilities have inherent challenges associated with concentrate management and disposal. Although enhanced permeate recovery and concentrate minimization are desired, membrane scaling due to inorganic constituents, such as silica, calcium, phosphate, and iron, hinders the process. To solve this problem, a new diatom-based photobiological process has been developed to remove these scaling constituents by biological uptake and precipitation. In this study, RO concentrate samples were collected from a full-scale advanced water reclamation facility in California and were treated in 3.8 and 57 L photobioreactors inoculated with a brackish water diatom Pseudostaurosira trainoriiPEWL001 using light-emitting diode bulbs or natural sunlight as a light source. The photobiological treatment removed 95% of reactive silica and 64% of calcium and enabled additional water recovery using a secondary RO at a recovery rate up to 66%. This represents 95% overall recovery, including 85% recovery in the primary RO unit. In addition to the scaling constituents, the photobiological treatment removed 12 pharmaceuticals and personal care products, as well as N-nitrosodimethylamine, from RO concentrate samples primarily via photolysis. This novel approach has a strong potential for application to brackish water desalination and advanced water purification in arid and semiarid areas.

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.

Recent evaluations of potable reuse treatment trains suggest that the use of UV and UV/H2O2may become increasingly common, particularly in systems employing ozone and/or biofiltration. This study provides a summary of photolysis rate constants and OH rate constants and demonstrates the applicability of semi-empirical relationships predicting OH exposure and trace organic contaminant (TOrC) abatement with UV/H2O2in matrices with low UV transmittance (e.g., <80%). The data are based on bench-scale experiments with 17 target compounds in 10 laboratory-filtered secondary wastewater effluents. As an alternative to OH exposure measurements with probe compounds, three different approaches for considering the impacts of matrix-specific OH scavenging on TOrC abatement are proposed: (1) estimation of ROH,UV(i.e., OH exposure per UV dose); (2) estimation of kUV/DOC, the pseudo first order rate constant based on the UV/DOC (dissolved organic carbon) ratio; and (3) assessment of TOrC abatement based on differential UV254absorbance or fluorescence. The level of laboratory investment varies with each approach, but there is a tradeoff in the accuracy of the predictions and whether they typically overestimate or underestimate actual TOrC abatement.

Trace organic compounds (TOrCs) continue to be detected in drinking water, and their recalcitrance makes them difficult to attenuate without installing expensive advanced treatment processes. Because human consumption is a small portion of net household water use, point‐of‐use (POU) devices may provide additional security against drinking water contaminants. This research evaluated three pitcher and two refrigerator POU devices using two waters. Refrigerator POU devices removed more TOrCs over the manufacturer's expected lifetime in terms of total mass than the pitcher POU devices. Average removal through all filters for nonionic, hydrophobic compounds was higher than for hydrophilic compounds in both waters. Removal of ionic compounds was enhanced by cation/anion exchange resins present in pitcher POU devices. Results indicated that POU devices are capable of removing significant amounts of organic contaminants in water. However, removal of a specific compound depends on its molecular properties, treatment technology implemented, and water quality and lifetime of the cartridge.

Realized and potential threats of water scarcity due in part to global climate change have increased the interest in potable reuse of municipal wastewater. Recalcitrant trace organic compounds (TOrCs), including pharmaceuticals and endocrine disrupting compounds in wastewater are often not efficiently removed by conventional wastewater treatment processes. Ozone application has been demonstrated to be a highly efficient oxidation process to attenuate TOrCs. However, operation of ozone oxidation can be challenging in wastewater due to variations in water quality that can impact critical control points through fluctuations in ozone demand/decay. Therefore, this study implemented three explanatory modeling techniques including multiple linear regression (MLR), artificial neutral network (ANN), and PC (principal component)-ANN to predict TOrCs removal by ozone oxidation in a secondary wastewater effluent. All the developed models displayed good agreements between the predicted TOrCs removal and the observed TOrCs removal with the explanatory variables (input variables) of ozone dose, total organic carbon (TOC) concentration, and rate constants of ozone and OH. PC-ANN displayed the highest predictive power in the external validation step (R2= 0.934) successively followed by ANN (R2= 0.914) and MLR (R2= 0.758). Based on the MLR model equation and the result of sensitivity analysis of the ANN model, TOC was found to have negligible effects on the TOrCs removal in a given water quality. Despite the predictive power of the ANN model, possible overfitting remains to be solved since the cross validation coefficient (q2) value calculated by the leave-one-out cross validation was not sufficient to ensure model predictive power. In contrast, the PC-ANN model was found to be robust across the scenarios applied. This study provides a guideline for software sensors to control ozone treatment processes in regards to TOrC oxidation and likely can be adapted to monitor disinfection as well.

Trace organic compounds (TOrCs) have been detected in drinking water sources for several years, raising concerns due to their potential risks to public health. The main contributor of TOrCs to drinking water is through wastewater discharges. However, there are several hundred TOrCs currently known with numerous new organic chemicals being released daily, making it unfeasible to monitor each one in water. This study used a detailed literature review and scoring system to establish a list of twenty priority indicator TOrCs in US wastewaters. Next, a rapid direct injection LC-MS/MS method for analysis of these compounds was developed without the need for an extraction step and only 80 μL sample volume while providing method reporting limits of 3–39 ng L−1for all but one TOrC (sucralose: 302 ng L−1). The elimination of an extraction step reduced matrix effects considerably making the method suitable for wastewater analysis. Method validation including matrix spike recoveries, linearity of calibration curve and inter- and intra-day variability was successfully performed. Finally, the twenty indicator TOrCs were evaluated in four different wastewater treatment plant (WWTP) effluents through four sample campaigns spread across a year. The occurrence data indicated that all indicator TOrCs were detected in at least three out of the four WWTP effluents. Sucralose, iohexol, TCPP, acesulfame and gemfibrozil were detected in all samples at the four WWTPs indicating they could be used as indicators of wastewater influence in receiving waters. DEET, caffeine, triclosan, iopromide and others are effective indicators at showing seasonal variations, treatment process efficacy, and consumption patterns. Overall, the impact of this study will help develop more effective monitoring programs for TOrCs in water reuse schemes.

In vitrobioassays, more recently referred to as “bioanalytical tools” in an attempt to emphasize their analytical purpose rather than the uncertain relation to adverse health outcomes, are often thought of as novel tools by water stakeholders. They have, however, been used for over half a century in assessment of recycled water quality. Today, millions of chemicals and formulations are available for commercial use and most have a high propensity to enter sewage collection systems. However, traditional health risk assessment methods involving animal testing at high doses and extrapolation to environmental relevant levels are vastly overwhelmed in capacity by the innumerable chemicals and transformation products potentially present in waters. Beyond the sheer number of chemicals, the interactions of these chemicals as complex mixtures is largely unaddressed in traditional regulatory schemes. Moreover, non-human animal models are often misleading due to differences in metabolism and associated pharmacokinetics. Thus, water professionals continue to struggle with ever increasing numbers of chemicals detected at trace levels in water and the potential interactions of these chemicals during mixture exposures. Bioanalytical tools offer a path forward towards more comprehensive chemical evaluations of water, which can provide greater public confidence in the ability of potable reuse schemes to produce clean and safe drinking water.

This article provides historical and current perspectives of the methods used and policies instituted to monitor and address the daunting list of chemical contaminants in water; progress is steadily made, but there is more work to be done.

Disinfection byproduct (DBP) formation during the treatment of raw Colorado River Water (CRW) using aqueous chlorine and ultraviolet (UV) light advanced oxidation processes (AOPs) was investigated. Here, CRW was combined with aqueous chlorine from two distinct sources (electrochemically-generated Mixed Oxidant Solution (MOS) and commercial sodium hypochlorite) and then exposed to ultraviolet C (UV-C) and ultraviolet A (UV-A) light. The impact of the treatment process on the structure of (NOM) in the CRW was examined, as well as the resulting production of various halogenated organic Disinfection By-Products (DBPs). Both AOP conditions tested resulted in destruction of chromophoric components of the NOM, while formation of total amounts of haloacetic acids and trihalomethanes was far below the US EPA regulated maximum contaminant level values for these contaminants, even though the UV and chlorine doses used in these studies were much higher than the typical doses used in an actual treatment process.

AbstractWater shortage arising from rapid population growth and relocation has produced an unprecedented degree of stress on regional water resources. Engineered solutions to relieve water stress are frequently based on the use of water of impaired initial quality. Chief among these impaired waters is reclaimed wastewater. For the most part, however, the breadth of both acceptable uses and use-dependent degree of treatment for reclaimed wastewater remain to be established. The chief advantages of direct potable reuse (DPR) relative to other forms of wastewater reclamation and reuse are that (i) all wastewater reclaimed for DPR can be readily used in water-stressed areas and (ii) delivery to points of use does not require a separate distribution system. The drawbacks are related to the need for highly competent, continuous on-line verification of water quality and the cost of treating all reclaimed wastewater to meet potable use requirements when only a small fraction will be used for potable purposes. We have attempted to explore those differences, providing quantitative comparisons where possible, to support selection among water reuse options in water-stressed areas.

An environmentally acceptable alternative to discharging recycled water to rivers, lakes, and other bodies of water is to use the water for irrigation of large areas of turfgrass. Such waters contain pharmaceuticals and personal care products (PPCPs), of which, some may have high mobility in irrigated soil–plant systems, potentially impacting groundwater resources. To determine the movement of 13 PPCPs under irrigated turfgrass conditions, a field‐based lysimeter study was conducted. After 745 d of monitoring, 9 of the 13 compounds were detected in drainage samples. The compounds with the highest detection rate in the drainage water were sulfamethoxazole and primidone in both soil types (100% in the loamy sand soil for both compounds and 50 and 65%, respectively, in the sandy loam soil) and carbamazepine in the loamy sand soil (50%). Factors influencing the movement of these compounds varied based on the compound and the imposed treatments. In the case of primidone, 94% of the variability in the mass discharge could be accounted for by taking into account the number of unsaturated pore volumes draining, the sand content, and the redox potential at 105 cm. The highest mass flux, scaled on a hectare basis, was recorded for sulfamethoxazole (0.25 g ha−1yr−1). Based on our results, restricting the use of recycled water based solely on the presence of PPCPs should only be a consideration at sites where soils are extremely sandy and irrigation regimes are not based on an evapotranspiration feedback approach.

Water has been a passionately contested issue in the United States (US) over the past century. Some argue for growth restrictions in drought-susceptible regions, but based on economic production, it may be worthwhile implementing creative measures to ensure continued and sustainable growth. The following economic analysis correlates water withdrawals in the 32 most populous metropolitan areas in the US with several economic indicators, including gross metropolitan product (GMP), income, and employment. The ratio of GMP to water withdrawals (GMP/H2O) ranged from (US)$58,788 per million gallons in Tampa to $939,555 per million gallons in San Jose ($15,532 to $248,231 per megaliter, respectively). Some drought-susceptible areas (e.g., Atlanta, Denver, Los Angeles, and Las Vegas) had relatively high GMP/H2O values, while others (e.g., Phoenix and San Diego) had relatively low GMP/H2O values. From a regional perspective, the Northwest had the strongest economy relative to its water withdrawals, and the Midwest had the weakest. These data indicate that the GMP/H2O metric can be used to justify water use in certain metropolitan areas but that the metric is less applicable to regional analyses due to unique aspects of local economies and water resource portfolios. [ABSTRACT FROM AUTHOR]

Hypochlorite solutions contain oxyhalide species such as perchlorate, chlorate, and bromate that form during and after manufacture. Such oxyhalide species have the potential to contaminate finished drinking water if adequate control measures are not taken to minimize their formation during manufacture, shipment, and storage of hypochlorite solutions. This article describes the rate of formation of perchlorate in hypochlorite solutions and discusses the chemistry behind a series of control strategies that utilities and manufacturers can implement to minimize oxyhalide formation and introduction into drinking water. Factors affecting the formation of perchlorate include temperature, ionic strength, hypochlorite concentration, and the presence of transition metal ions. The authors conclude that with proper manufacture, storage conditions, and handling, formation of perchlorate, chlorate, and bromate can be minimized. If care is not taken during manufacture and storage of hypochlorite solutions, however, perchlorate, chlorate, and bromate levels can exceed health‐based guidelines in drinking water.

One of the two main objectives of this study is to use two pass membrane desalination system and to oxidize permeate of the first pass with ozone, as disinfection by products (DBPs) formed by ozone are rather limited. Second objective of this work; is to increase the pH levels to 10 in the permeate of the first desalination pass in order to promote dissociation of boric acid (B(OH)3) to borate (B(OH)4-). Negatively charged borate can easily be removed by membrane systems because of the charge repulsion. Oxidation efficiency of ozone under pH 10 conditions and the buffer effect of borate were also focused on in this study. Double pass nanofiltration/ reverse osmosis (NF/RO) membrane filtration systems were used for the desalination of model seawater. Permeate of the first membrane filtration was adjusted to pH 10 and oxidized with ozone for 30 mins. Oxidized permeate was then fed to the second membrane filtration in order to investigate boron removal and bromate formation and removal. Boron removal was improved effectively by all tested membranes at pH 10. Boron removal rates for NE70, NE90 and FL membranes increased from 4% to 7%, 11% to 28% and 37% to 84% respectively. Bromate was formed effectively with ozone oxidation at pH 10 and removed (>90%) by the RO membrane (FL) and (>75%) by one of the NF membranes (NE90) in the second pass.

This study demonstrates a relative exposure to estrogenic activity and other trace contaminants in drinking water compared with food, beverage, and air exposure. Drinking water for nearly 28 million people in 17 US cities plus 40 food and beverage items was screened for 51 trace contaminants, including suspected endocrine disrupting chemicals (EDCs), pharmaceuticals, personal care products, pesticides, phytoestrogens, and total in vitro estrogenic activity. Only three drinking water samples exhibited measurable estrogenic activity (0.19–0.77 ng/L as estradiol equivalents), whereas 34 of the 40 food and beverage items had measurable estrogenic activity (median estradiol equivalents, 0.55–4,200 ng/L). On an adult, per‐serving basis, food and beverage intake of estrogenic activity was 4–21,000 times greater than in municipal drinking water. Of the literature studies available, air exposure for six suspected EDCs analyzed in this study resulted in at least 30–36,000 times the exposure from drinking water.

This article discusses a comprehensive Water Research Foundation study that was initiated to determine the removal potential of various endocrine disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) during a variety of conventional and advanced wastewater treatment processes. To complete the evaluation, specific analytical methods were developed for representative target analytes. The article discusses analysis methods, treatment methods, sample selection, and treatment results.

The concentrations of selected wastewater contaminants, including conductivity, nitrate, and pharmaceuticals and endocrine disrupting compounds (EDCs), were monitored from 2003 to 2007 in Lake Mead, the raw (untreated) drinking water for southern Nevada. Monitoring was also conducted in two inflows to Lake Mead: the Colorado River and the wastewater‐dominated Las Vegas Wash. There was a statistically significant increase in source water conductivity, nitrate, and pharmaceutical and EDC concentrations over this time period, concomitant with a statistically significant decline in the volume of Lake Mead. There was no statistically significant increase in conductivity and nitrate in the Colorado River or the Las Vegas Wash over this period, nor was there an increase in flow of the Las Vegas Wash or Colorado River. Thus, the deterioration of source drinking water quality is due to the decrease in the volume of Lake Mead which has been attributed to drought. This phenomenon may also be a harbinger of how water quality may be adversely affected by climate change as patterns of surface water flow shift and treated wastewater becomes a larger fraction of surface water flow in some areas.

Corona discharge is emerging as a promising advanced oxidation process (AOP) for the treatment of a variety of organic contaminants, including compounds that are not effectively destroyed by more common AOPs. This paper presents laboratory and field results describing the destruction of regulated and Contaminant Candidate List (CCL) compounds in tertiarytreated wastewater effluent and contaminated groundwater during the operation of a novel Hydro-Non-Thermal-Plasma (HNTP) AOP system. The system generates a plasma discharge above the target water matrix, which emits an “electron wind”, ultraviolet (UV) irradiation, O3(g)and hydroxyl radicals (•OH) into a relatively thin water layer. The synergism between these oxidizing agents results in efficient degradation of refractory organics (typically >95%) rendering further chemical dosage unnecessary. Batch experiments revealed the dominating kinetics to be first order for MTBE (k= 7.5 × 10-4s-1) and TCE (k = 4.8 × 10-4s-1). This study is the first report of pilot-scale HNTP destruction of (mainly) TCE, 1,4-dioxane and NDMA from a contaminated water source (groundwater in California). The pilot-scale HNTP reactor showed high removal efficiencies of 95.3%, 91.7% and 95.3%, for these three contaminants, along with energy efficiency (EEO) values comparable to other AOP systems.

This article discusses a study by the Southern Nevada Water Authority that investigated the rate of perchlorate and other oxyhalide species formation in hypochlorite solutions. The motivation for the study came from the recently proposed Drinking Water System Security Act of 2009 (H.R. 3258) that could decrease the usage of chlorine gas at water and wastewater utilities and increase hypochlorite use. The study discusses the risks and tradeoffs of certain processes in order to avoid problems related to competing compliance standards. The article presents study findings and implications, and makes recommendations on the following topics: dilution on delivery; storage temperature; control pH after dilution; use solutions as soon as possible; control removal of transition metal ions; storage time; and, minimize bromate in brine.

The effect of ozone oxidation on the second order reaction rate constant between effluent organic matter (EfOM) and hydroxyl radical (•OH), kOH-EfOM, has been evaluated. Previously, this rate constant was measured for EfOM samples collected from five geographically distributed wastewater treatment plants. The kOH-EfOM values ranged from 2.70 - 12.1 - 108MC -1s-1. One additional EfOM sample collected during this study was preoxidized using different ozone dosages. While oxidation by ozone resulted in considerable change to the physicochemical properties of the EfOM the reaction rate constant (measured initially as (4.38 ± 0.06) × 108MC -1s-1) did not significantly change. This indicates that the reaction rate constant could be assumed to be constant during the application and modeling of advanced oxidation processes for water reuse applications.

This article discusses endocrine disrupting chemicals (EDCs) and pharmaceuticals that are found in municipal wastewater treatment plant effluents and in surface waters influenced by effluents. Sources of origination and exposure, health effects on humans and aquatic life, regulations, water treatment, source water protection, risks, and ongoing research are discussed.

The Chemical Scoring and Ranking Assessment Model (SCRAM) has been described in Parts I–III of this series (Snyder et al., 1999a; 1999b; 1999c). SCRAM is a chemical scoring and ranking (CSR) system that scores chemicals on the basis of bioaccumulation potential, environmental persistence, and toxicity. Part IV describes various tests and descriptions of the performance of this system. A group of 21 representative chemicals was chosen and scored to test the system. For those chemicals, the percentages of the scores associated with fate-related properties and associated with data uncertainty were determined. The scoring of four of these chemicals is described in greater detail, and the suitability of the scores is discussed. An analysis of the sensitivity of the system to incomplete data sets is presented. And finally, the discriminatory power of the system is described.

New detection methods have increased awareness of chemicals with the potential to interfere with the normal function of the endocrine system. As a result of new and more sensitive methods for detecting chemicals and the development of scientific methods that better determine their biological effects, unregulated contaminants that were previously undetected by water professionals have become of interest to the public and the press. A source water issue that has taken a high profile in Las Vegas, Nev., relates to chemicals with the potential to act as endocrine disruptors. Las Vegas is one of the first large urbanized areas in the United States where studies have been conducted to determine the presence of these chemicals in the drinking water supply. This article discusses the potential health effects, detection methods, and regulatory considerations of these chemicals.

Iodinated X-ray contrast media (ICM) are a class of pharmaceuticals that are ubiquitously found at trace levels (µg/L) in wastewater, surface water, groundwater, and drinking water. Due to their polar features, they are not effectively removed during conventional water treatment and provide an iodine source for the formation of iodinated-disinfection by-products (I-DBPs) during disinfection. This work examined the suitability of organic parameters (i.e. total organic carbon (TOC), ultraviolet absorbance (UVA254), total fluorescence (TF) and specific ultraviolet absorbance (SUVA)), as surrogate correlation models to estimate the removal of seven target ICMs. Three advanced oxidation processes (AOPs), LPUV/H2O2, LPUV/Cl2and LPUV/NH2Cl, were applied to develop the surrogate correlation models. Pearson correlation coefficients were compared with linear correlation models to determine the ideal surrogate parameter for each model type. The formation of iodinated-haloacetic acids (I-HAAs) were also monitored for each AOP treatment. Results did not show any significant differences for ICM attenuation across the AOP treatments, illustrating UV photolysis is the main driving force to attenuate ICMs. Surrogate correlation models demonstrated a good correlation (R2= 0.8211 and 0.7887) and strong Pearson correlation (R = 0.9602 and 0.8881) for UVA254during LPUV/Cl2and LPUV/H2O2treatment. Additionally, two I-HAA, monoidoacetic acid (MIAA) and bromoiodoacetic acid (BIAA), were detected (up to 2.4 µg/L) after LPUV/Cl2and LPUV/NH2Cl AOP treatment.

Focuses on the accumulation of pharmaceuticals on waterways and its environmental effects. Impact of endocrine-disrupting chemicals in wasterwater to aquatic animals; Effect of xenobiotics to organisms in bodies of water.