Search

Traditional approaches toward evaluating oil spill mitigation effectiveness in drinking water supplies using analytical chemistry can overlook residual hydrocarbons and treatment byproducts of unknown toxicity. Zebrafish (Danio rerio) were used to address this limitation by evaluating the reduction in toxicity to fish exposed to laboratory solutions of dissolved crude oil constituents treated with 3 mg/L ozone (O(3)) with or without a peroxone-based advanced oxidation process using 0.5 M H(2)O(2)/M O(3) or 1 M H(2)O(2)/M O(3). Crude oil water mixtures (OWMs) were generated using three mixing protocols—orbital (OWM-Orb), rapid (OWM-Rap), and impeller (OWM-Imp) and contained dissolved total aromatic concentrations of 106–1019 μg/L. In a first experiment, embryos were exposed at 24 h post fertilization (hpf) to OWM-Orb or OWM-Rap diluted to 25%–50% of full-strength samples and in a second experiment, to untreated or treated OWM-Imp mixtures at 50% dilutions. Toxicity profiles included body length, pericardial area, and swim bladder inflation, and these varied depending on the OWM preparation, with OWM-Rap resulting in the most toxicity, followed by OWM-Imp and then OWM-Orb. Zebrafish exposed to a 50% dilution of OWM-Imp resulted in 6% shorter body length, 83% increased pericardial area, and no swim bladder inflation, but exposure to a 50% dilution of OWM-Imp treated with O(3) alone or with 0.5 M H(2)O(2)/M O(3) resulted in normal zebrafish development and average total aromatic destruction of 54%–57%. Additional aromatic removal occurred with O(3) + 1 M H(2)O(2)/M O(3) but without further attenuation of toxicity to zebrafish. This study demonstrates using zebrafish as an additional evaluation component for modeling the effectiveness of freshwater oil spill treatment methods.

An emerging class of unregulated disinfection byproducts, halobenzoquinones (HBQs), has gained recent interest following suggestions of enhanced toxicity compared to regulated disinfection byproducts. While the kinetics of HBQ hydrolysis in water have been well characterized, the stability of HBQs in cell culture media, a critical parameter when evaluating toxicity in vitro, has been overlooked. The objective of this study was: (1) to contrast the stability of a prevalent HBQ, 2,6-dichloro-1,4-benzoquinone (DCBQ), in cell culture media and water, and (2) to evaluate the cytotoxicity of parent and transformed DCBQ compounds as well as the ability of these compounds to generate intracellular reactive oxygen species (ROS) in normal human colon cells (CCD 841 CoN) and human liver cancer cells (HepG2). The half-life of DCBQ in cell media was found to be less than 40 min, compared to 7.2 h in water at pH 7. DCBQ induced a concentration-dependent decrease in cell viability and increase in ROS production in both cell lines. The parent DCBQ compound was found to induce significantly greater cytotoxicity compared to transformed DCBQ products. We demonstrate that the study design used by most published studies (i.e., extended exposure periods) has led to a potential underestimation of the cytotoxicity of HBQs by evaluating the toxicological profile primarily of transformed HBQs, rather than corresponding parent compounds. Future in vitro toxicological studies should account for HBQ stability in media to evaluate the acute cytotoxicity of parent HBQs.

This study investigated the effects of ferrate and ozone pre-oxidation on disinfection byproduct (DBP) formation from subsequent chlorination or chloramination. Two natural waters were treated at bench-scale under various scenarios (chlorine, chloramine, each with ferrate pre-oxidation, and each with pre-ozonation). The formation of brominated and iodinated DBPs in fortified natural waters was assessed. Results indicated ferrate and ozone pre-oxidation were comparable at molar equivalent doses for most DBPs. A net decrease in trihalomethanes (including iodinated forms), haloacetic acids (HAAs), dihaloacetonitrile, total organic chlorine, and total organic iodine was found with both pre-oxidants as compared to chlorination only. An increase in chloropicrin and minor changes in total organic bromine yield were caused by both pre-oxidants compared to chlorination only. However, ozone led to higher haloketone and chloropicrin formation potentials than ferrate. The relative performance of ferrate versus ozone for DBP precursor removal was affected by water quality (e.g., nature of organic matter and bromide concentration) and oxidant dose, and varied by DBP species. Ferrate and ozone pre-oxidation also decreased DBP formation from chloramination under most conditions. However, some increases in THM and dihaloacetonitrile formation potentials were observed at elevated bromide levels.

Effets d'une preozonation et de la coagulation par alun, separement ou en association, sur l'elimination des precurseurs de composes organiques halogenes dans le traitement de l'eau potable

Halobenzoquinones (HBQs) are emerging disinfection by-products (DBPs) that are postulated drivers of bladder carcinogenicity. Prior assessments of 2,6-dichloro-1,4-benzoquinone (DCBQ) occurrence in drinking water distribution systems have revealed a gradual decline with increasing distance from points of entry. While this signals a degradation pathway, there is limited quantitative data on rate of that degradation. A systematic evaluation of DCBQ hydrolysis was performed, resulting in a rate law that is first order in both hydroxide [OH−] and [DCBQ]. The impact of temperature on that rate was characterized according to the Arrhenius relationship. Under the conditions tested (pH~7.2, T = 20°C) chloramine did not significantly impact DCBQ concentrations. However, DCBQ was rapidly degraded in solutions containing free available chlorine (FAC). Kinetic analysis showed non-integer order with respect to FAC. Further investigation led to a model that invoked reaction with dichlorine monoxide (Cl2O) as well as FAC.

Background Several studies have suggested that global DNA methylation in circulating white blood cells (WBC) is associated with breast cancer risk. Methods To address conflicting results and concerns that the findings for WBC DNA methylation in some prior studies may reflect disease effects, we evaluated the relationship between global levels of WBC DNA methylation in white blood cells and breast cancer risk in a case-control study nested within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO) cohort. A total of 428 invasive breast cancer cases and 419 controls, frequency matched on age at entry (55–59, 60–64, 65–69, ≥70 years), year of entry (on/before September 30, 1997, on/after October 1, 1997) and period of DNA extraction (previously extracted, newly extracted) were included. The ratio of 5-methyl-2’ deoxycytidine [5-mdC] to 2’-deoxyguanine [dG], assuming [dG] = [5-mdC] + [2’-deoxycytidine [dC]] (%5-mdC), was determined by liquid chromatography-electrospray ionization-tandem mass spectrometry, an especially accurate method for assessing total genomic DNA methylation. Results Odds ratio (OR) estimates and 95% confidence intervals (CI) for breast cancer risk adjusted for age at entry, year of entry, and period of DNA extraction, were 1.0 (referent), 0.89 (95% CI, 0.6–1.3), 0.88 (95% CI, 0.6–1.3), and 0.84 (95% CI, 0.6–1.2) for women in the highest compared to lowest quartile levels of %5md-C (p for trend = .39). Effects did not meaningfully vary by time elapsed from WBC collection to diagnosis. Discussion These results do not support the hypothesis that global DNA hypomethylation in WBC DNA is associated with increased breast cancer risk prior to the appearance of clinical disease.

Exposure to disinfection byproducts (DBPs) in chlorinated drinking water has been positively associated with increased risk of colon, bladder, and rectum cancers. Iodinated DBPs (I-DBPs) are of concern as this class exhibits enhanced cytotoxicity and genotoxicity compared to those of chlorinated and brominated equivalents in Chinese hamster ovary (CHO) cells. We tested the impact of six I-DBPs on immortalized normal human colon epithelial cells (CCD 841 CoN). Our assay showed the following rank order of cytotoxicity of the I-DBPs: iodoacetic acid (IAA) > iodoacetamide (IAcAm) > bromoiodoacetamide (BIAcAm) > chloroiodoacetamide (CIAcAm) > bromoiodoacetic acid (BIAA) ≈ diiodoacetic acid (DIAA). The enhanced cytotoxicity of IAA compared with those of other haloacetic acids agrees with studies conducted on CHO cells. IAcAm was found to be 3.5 times more cytotoxic than BIAcAm and 9.4 times more cytotoxic than CIAcAm. The cytotoxicity of both dihaloacids (i.e., BIAA and DIAA) was

Ozone is used in three ways: as a biocide, as a classical oxidant, and as a pretreatment for improving the performance of subsequent processes. The ability of ozone to act as a disinfectant and classical oxidant has long been known. Ozone can also be used at any intermediate point if it is needed to control growths within the plant. The addition of ozone at multiple locations within water treatment plants is thus a natural outgrowth of its diverse applications. The increase in the use of ozone worldwide is partly due to the pioneering work of a small number of engineers and scientists. The chapter reviews the literature that deals with reduced iron and manganese removal, emphasizing studies utilizing ozone. The presence of high levels of bicarbonate can modify consumption of oxidant such that less ozone is required. Perhaps the most convincing link between raw water quality and coagulating effects of ozone concern calcium hardness.

INTRODUCTION. PURPOSE OF BOOK. CURRENT ROLE OF OZONE IN DRINKING WATER TREATMENT. History of Ozone Use. Current Status in North America. Current Status in Europe. Current Status in the Middle East and Far East. Current Status in the World at Large. THE FUTURE. FUNDAMENTAL ASPECTS. CHEMISTRY-INTRODUCTION. Molecular Ozone Reactivity. Decomposition of Ozone. Reaction With Inorganics. Oxidation of Synthetic Organic Compounds. Reaction of Ozone on Cell Constituents In Vitro. Reactions With Aquatic Humic Substances. TOXICOLOGY. Principles and Limitations of Toxicological Testing. Short-Term Mutagenicity and Genotoxicity Tests. Short-Term Bioassay for Carcinogenic/Mutagenic By-Products. Subchronic Bioassays on Nongenotoxic Ozone Disinfection By-Products. THEORETICAL ASPECTS OF OZONE ANALYSIS-INTRODUCTION. Ozone Measurements in the Gas Phase. Interferences Affecting Dissolved Ozone Measurements. Constraints of Dissolved Ozone Measurements. Reporting Gas-Phase Ozone Concentration. Ozone Measurement in the Aqueous Phase (Ozone Residual). Gas-Phase Measurements. Conclusions. OZONE GENERATION. Basic Principles. Ozone Generation By Corona Discharge. Alternative Methods. OZONE GAS TRANSFER. Solubility of Ozone in Water. Contacting of Ozone With Water. PRACTICAL APPLICATION OF OZONE: PRINCIPLES AND CASE STUDIES. INTRODUCTION. Uses of Ozone. Current Practice. IRON AND MANGANESE REMOVAL. Principles of Removal. Case Studies. Design Considerations. COLOR ABATEMENT. Definition and Origin of Color. Treatments for Color Removal. Case Study: Tullich Water Treatment Works, Oban, Scotland. Design Considerations. CONTROL OF TASTES AND ODORS. Introduction. Definition of Tastes and Odors and Evaluation Techniques. Odor- and Taste-Producing Compounds and Their Origin. Odor and Taste Elimination Processes. Case Studies: Choisy-le-Roi and Morsang-sur-Seine. Design Considerations. ELIMINATION OF SYNTHETIC ORGANIC COMPOUNDS. Uncatalyzed Ozonation. Advanced Oxidation Processes. Case Study on Ozone-GAC Treatment: Rouen La Chapelle Water Utility (Seine Maritime, France). Design Considerations. PARTICULATE REMOVAL. Principles. Case Studies. Special Considerations for Process Evaluation, Design, and Control. ALGAE REMOVAL. Problems Connected With the Presence of Plankton in the Water. Review of the Principal Treatments Currently Used for Plankton Removal. Advantages of Ozonation in Treating Plankton-Laden Water. Case Studies. DISINFECTION. Principles. Case Studies. DISINFECTION BY-PRODUCT CONTROL. Introduction. Formation of Ozonation By-Products. Primary Effects on General Disinfection By-Product Formation. Secondary Effects of Preozonation on Disinfection By-Products. Case Study: The Belle Glade Water Treatment Plant. Design of Pilot Studies for DBP Control. MINIMIZATION OF ADVERSE HEALTH EFFECTS. Introduction. Case Studies: Subchronic, Carcinogenic, and Mutagenic Effects of Ozonated Drinking Water. Unresolved Questions Concerning the Toxicology of Ozonation By-Products. Conclusions and Recommendations. BIOLOGICAL STABILIZATION. Introduction. Fundamental Aspects. Stabilization Processes. Design Considerations. ENGINEERING ASPECTS. TREATABILITY STUDIES. General Study Considerations. Study Approach. Bench-Scale Studies. Pilot- and Demonstration-Scale Studies. Parameter Measurements. Interpretation of Results. Process Recommendations. FEED GAS PREPARATION. Feed Gas Selection. Feed Gas Quality. Gas Preparation Systems. OZONE GENERATION. Commercial Scale Ozone Generator Operating Principles. Generator Technology and Materials Used. Electrical Parameters and Variables That Affect Ozone Production. Ozone Generator Cooling. Various Types of Ozone Generators. DESIGN OF CONTACT CHAMBERS AND DIFFUSION SYSTEMS. Overall Considerations. Ozone Dissolution Techniques. Contactor and Dissolution System Selection. Contactor Design Considerations. INSTRUMENTATION AND CONTROL SYSTEMS. General Considerations. Dewpoint Measurement and Drying System Control. Gas Flow Meters. Alarms. OZONE DESTRUCTION SYSTEMS. Reasons for Ozone Destruction. Current Design Practice. Other Ozone Destruction Methods. CORROSION CONSIDERATIONS AND OZONE-RESISTANT MATERIALS. Gas Preparation System. Material Selection for Ozonation Systems. RETROFIT OF OZONE SYSTEMS. Introduction. Approach to Retrofit Project Development. Process Considerations. PERFORMANCE EVALUATION. Introduction. Specification Requirements. Example Power Evaluation Test. OTHER CONSIDERATIONS. Noise Control. Structural Arrangement. CHECKLISTS FOR OZONE SYSTEM DESIGN. OPERATING AN OZONATION FACILITY. OPERATING METHODS. Air as Feed Gas. Oxygen as Feed Gas. OZONE SYSTEM RELIABILITY. Design and Standby Capacities. Reliability of Equipment. REQUIRED PLANT MAINTENANCE. Air Compressors. Aftercooler and Refrigerant Dryer. Moisture Separators and Air Filters. Desiccant Dryer. Ozone Generator. Contractor and Dissolution System. Destructor. Control Boards and Electronic Equipment. EMPLOYEE TRAINING. Operator Participation in Pilot Tests. Training Personnel During Facility Startup. Plant O & M Manuals. Troubleshooting Schedules. SAFETY. Gaseous Ozone Exposure-The Labor Code. Protection of Personnel. ECONOMICS OF OZONE SYSTEMS: NEW INSTALLATIONS AND RETROFITS. "ORDER-OF-MAGNITUDE" ESTIMATES OF OZONE SYSTEM COSTS. Procedure for Obtaining Estimated Capital Cost. Proposed Procedure for Obtaining Estimated O & M Costs. CONSIDERATIONS FOR ESTIMATING THE COST OF AN OZONATION FACILITY. Considerations for Assessing Capital Costs. Considerations for Assessing Operating and Maintenance Costs. Considerations for Assessing Secondary Benefits and Costs. INFLUENCE OF THE DESIGNED OZONATION SYSTEM ON THE CAPITAL COST. Ozone Requirement Including Standby. System Size and Housing. Availability of Power to the Site. Contactors and Associated Dissolution System. Degree of Automation. INFLUENCE OF THE DESIGNED OZONATION SYSTEM ON O & M COSTS. O & M Costs of Feed Gas Train. O & M Cost of Ozone Generation. O & M Cost of the Dissolution Systems. O & M Cost of Ozone-Containing Offgas Destruction Systems. Overview of Total O & M Costs. CASE STUDIES. Case Studies of Capital Costs. Case Studies of Operating Cost. APPENDIX A: OZONE SYSTEM TERMINOLOGY, MEASUREMENTS, AND CONVERSIONS. INTRODUCTION. STANDARD CONDITIONS. OZONE CONSIDERATION. Measuring Ozone Concentration. Ozone Concentration Conversion Factors. PRODUCT GAS OZONE PRODUCTION. OZONE TRANSFER EFFICIENCY. INDEX.

The formation and occurrence of haloacetonitriles (HANs) in drinking water is of increasing concern because recent data have shown that they are the major contributors to DBP-associated toxicity of disinfected waters. Earlier research on HAN formation had established free amino acids as important HAN precursors due to their high reactivity with chlorine. However, free amino acids are unlikely to be the primary precursors for HANs in natural waters, mainly because the actual concentrations of these compounds are too low to sufficiently account for observed HAN formation. On the other hand, combined amino acids (i.e., peptides and proteins) are of much higher abundance even though it is unclear if they can contribute to HAN formation given that nearly all the amino nitrogen is tied up in peptide linkages. In order to clarify the reactivity of combined amino acids with chlorine to form HANs, dichloroacetonitrile (DCAN) formation kinetics was compared between free aspartic acid and two aspartyl-containing tetrapeptides (i.e., Asp-Asp-Asp-Asp and Arg-Gly-Asp-Ser). Results indicated that aspartyl residue could also lead to DCAN formation upon chlorination, whereas the rate of DCAN formation was much slower compared to that from free aspartic acid chlorination. Moreover, DCAN formation from the two model peptides was catalyzed by high pH. This is because chlorine-induced peptide backbone degradation is the key to DCAN formation from the chlorination of combined amino acids and this slow stepwise process is base-catalyzed. Perhaps most importantly, regardless of the precursors, DCAN was continuously formed but simultaneously degraded especially at alkaline pHs, leaving the corresponding N-chloro-2,2-dichloroacetamide (N-Cl-DCAM) and dichloroacetic acid (DCAA) as major end products. It was observed that over increasing chlorine exposure, there exists an important transition from initial organic precursors through metastable chlorination intermediates (e.g., DCAN and N-Cl-DCAM) and finally to stable end products (e.g., DCAA). By weighting DBP concentrations by their respective cytotoxic potencies, it is estimated that the aggregate cytotoxicity of chlorinated water would reach its maximum at relatively short chlorine contact times. In general, shorter water age and lower pH both resulted in higher levels of metastable intermediates (i.e., DCAN) and thus higher levels of aggregate calculated cytotoxicity. The resulting toxicity profile is different from the prevailing notion that supports current DBP regulations. Therefore, there is a risk that by placing regulatory limits and control strategies exclusively on regulated end products (e.g., HAAs), the overall toxicity of drinking water might be inadvertently elevated.

Iodinated disinfection by-products (I-DBPs) have recently emerged as part of the pool of DBPs of public health concern. Due to limitations in measuring individual I-DBPs in a water sample, the surrogate measure of total organic iodine (TOI) is often used to account for the sum of all I-DBPs. In this study, TOI and total iodine (TI) are quantified in raw and treated waters in treatment trains at three sites in the Northeast United States. The occurrence, magnitude, and seasonality of these species was investigated within each sampling train and across the different sites. A regression model was developed to explore how TOI occurrence varies with routinely measured physical and chemical parameters in a water sample. The TOI and TI concentration at the three sites ranged from below the method detection limit to 18 µg/L and from 3 and 18.9 µg/L, respectively. There was substantial inter-monthly variability in TOI without a clear seasonal signal, and the concentration of TOI did not increase upon treatment. The results of the multivariate regression model showed that dissolved organic carbon (DOC), specific UV254 absorbance (SUVA), combined chlorine residual (TCl2), and pH were all significantly related to TOI concentration to varying degrees. A Tobit model was fit to show TOI predictions against observed (measured) TOI values. The model could explain approximately 46% of the variance of TOI concentrations in the treated waters.

Haloacetamides (HAMs) are a class of newly identified nitrogenous disinfection byproducts (N-DBPs) whose occurrence in drinking waters has recently been reported in several DBP surveys. As the most prominent HAM species, it is commonly acknowledged that 2,2-dichloroacetamide (DCAM) is mainly generated from dichloroacetonitrile (DCAN) hydrolysis because the concentrations of these two compounds are often well correlated. Instead of DCAM, a previously unreported N-DBP, N-chloro-2,2-dichloroacetamide (N-Cl-DCAM), was confirmed in this study as the actual DCAN degradation product in chlorinated drinking waters. It is suspected that N-Cl-DCAM has been erroneously identified as DCAM, because its nitrogen-bound chlorine is readily reduced by most commonly used quenching agents. This hypothesis is supported by kinetic studies that indicate almost instantaneous N-chlorination of DCAM even at low chlorine residuals. Therefore, it is unlikely that DCAM can persist as a long-lived DCAN decomposition product in systems using free chlorine as a residual disinfectant. Instead, chlorination of DCAM will lead to the formation of an equal amount of N-Cl-DCAM by forming a hydrogen bond between hypochlorite oxygen and amino hydrogen. Alternatively, N-Cl-DCAM can be produced directly from DCAN chlorination via nucleophilic addition of hypochlorite on the nitrile carbon. Due to its relatively low pKa value, N-Cl-DCAM tends to deprotonate under typical drinking water pH conditions, and the anionic form of N-Cl-DCAM was found to be very stable in the absence of chlorine. N-Cl-DCAM can, however, undergo acid-catalyzed decomposition to form the corresponding dichloroacetic acid (DCAA) when chlorine is present, although those acidic conditions that favor N-Cl-DCAM degradation are generally atypical for finished drinking waters. For these reasons, N-Cl-DCAM is predicted to have very long half-lives in most distribution systems that use free chlorine. Furthermore, an analytical method using ultra performance liquid chromatography (UPLC)/negative electrospray ionization (ESI-)/quadrupole time-of-flight mass spectrometry (qTOF) was developed for the detection of a family of seven N-chloro-haloacetamides (N-Cl-HAMs). Combined with solid phase extraction (SPE), the occurrence of N-Cl-DCAM and its two brominated analogues (i.e., N-chloro-2,2-bromochloroacetamide and N-chloro-2,2-dibromoacetamide) was quantitatively determined for the first time in 11 real tap water samples. The discovery of N-Cl-DCAM or, more broadly speaking, N-Cl-HAMs in chlorinated drinking waters is of significance because they are organic chloramines, a family of compounds that is perceived to be more toxicologically potent than halonitriles (e.g., DCAN) and haloamides (e.g., DCAM), and therefore they may pose greater risks to drinking water consumers given their widespread occurrence and high stability.

International audience; The potential formation of nitrogenous disinfection byproducts (N-DBPs) was investigated from the chloramination of nitrogenous and non-nitrogenous aromatic compounds. All molecules led to the formation of known N-DBPs (e.g., dichloroacetonitrile, dichloroacetamide) with various production yields. Resorcinol, a major precursor of chloroform, also formed di/trichloroacetonitrile, di/trichloroacetamide, and haloacetic acids, indicating that it is a precursor of both N-DBPs and carbonaceous DBPs (C-DBPs) upon chloramination. More detailed experiments were conducted on resorcinol to understand N-DBPs formation mechanisms and to identify reaction intermediates. Based on the accurate mass from high resolution Quadrupole Time-of-Flight GC–MS (GC–QTOF) and fragmentation patterns from electronic impact and positive chemical ionization modes, several products were tentatively identified as nitrogenous heterocyclic compounds (e.g., 3-chloro-5-hydroxy-1H-pyrrole-2-one with dichloromethyl group, 3-chloro-2,5-pyrroledione). These products were structurally similar to the heterocyclic compounds formed during chlorination, such as the highly mutagenic MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone) or halogenated pyrroles. To our knowledge, this is the first time that the formation of halogenated nitrogenous heterocyclic compounds is reported from chloramination process. The formation of these nitrogenous byproducts during chloramination might be of concern considering their potential toxicity.

A new spectrophotometric method for the determination of aqueous ozone in water matrices was developed. This method is based on the reaction of ozone and 2.2’-azino-bis (3-ethylbenzothiazoline-6-sulfonate), ABTS), which can be oxidized from a colorless material to a green-colored cation ABTS.+. This reaction product presents at least four peaks (415, 650, 732, 820 nm), which can be helpful in the presence of inferences from organic matter in water samples. This method is quite sensitive due to the high molar absorptivity of the product (ɛ = M−1.cm−1). The stoichiometry of the reaction of ozone with ABTS is 1:1 when ABTS is in excess. The detection limit of this ABTS method was determined to be 1.2 µg/L. The increase in absorbance due to ABTS.+ generation is linear with respect to ozone added (5 μg/L–5 mg/L) at pH 2 (controlled with phosphate buffer). The reagent ABTS reacts with ozone almost instantaneously (less than 1 sec). The product, ABTS.+, is quite stable in both pure and natural water samp...

Oxidative treatment of iodide-containing waters can form toxic iodinated disinfection byproducts (I-DBPs). To better understand the fate of iodine, kinetics, products, and stoichiometries for the reactions of ferrate(VI) with iodide (I–) and hypoiodous acid (HOI) were determined. Ferrate(VI) showed considerable reactivities to both I– and HOI with higher reactivities at lower pH. Interestingly, the reaction of ferrate(VI) with HOI (k = 6.0 × 103 M–1 s–1 at pH 9) was much faster than with I– (k = 5.6 × 102 M–1 s–1 at pH 9). The main reaction pathway during treatment of I–-containing waters was the oxidation of I– to HOI and its further oxidation to IO3– by ferrate(VI). However, for pH > 9, the HOI disproportionation catalyzed by ferrate(VI) became an additional transformation pathway forming I– and IO3–. The reduction of HOI by hydrogen peroxide, the latter being produced from ferrate(VI) decomposition, also contributes to the I– regeneration in the pH range 9–11. A kinetic model was developed that could w...

The analysis of endocrine disrupting compounds (EDCs) and pharmaceutical and personal care products (PPCP), present at trace level in surface waters, is often expensive, time-consuming, and complex. Implementing effective monitoring strategies for these compounds is essential to determine the types of analytes, sampling locations, and sampling frequencies. Multivariate analyses were used to investigate the patterns of EDCs and PPCPs in Lake Mead, Nevada, for these purposes. The results of cluster analysis and principal component analysis to identify the patterns among compounds demonstrated that selected pharmaceuticals tended to be present together with each other, whereas hormones did not show patterns with other compounds. The results of cluster analysis and discriminant analysis to investigate the spatial variation of EDCs and PPCPs eliminated redundant sampling locations, verifying the current selection of sampling locations in Lake Mead. The results of autocorrelation provided optimal sampling frequencies for EDCs and PPCPs, suggesting either monthly or quarterly monitoring of these compounds in Lake Mead. The patterns of the compounds could be site specific; depending on weather and hydrological conditions of the water systems, but this study's approaches will facilitate effective assessment and monitoring of EDCs and PPCPs in surface water.

Lignin is the most abundant aromatic plant component in terrestrial ecosystems. This study was conducted to determine the contribution of lignin residues in natural water to the formation of disinfection byproducts (DBPs) in drinking water. We investigated the formation of different classes of DBPs from lignin model compounds, lignin polymers, and humic substances using two common disinfection techniques, chlorination and chloramination. The contributions of lignin to the overall formation of DBPs from these organic products were determined based on the observed abundances of individual lignin phenols and their DBP yields. Model lignin phenols generally produced higher trichloroacetic acid (TCAA) yields than chloroform and dichloroacetic acid (DCAA) during chlorination. Lignin phenols generally produced higher DBP yields but lower percentages of unknown total organic halogen compared to bulk humic substances and lignin polymers. The relative significance of lignin phenols as chlorination DBP precursors generally follows the order of TCAA > DCAA&chloroform. The relative significance of lignin phenols to DBP formation by chloramination follows the order: TCAA > DCAA&DCAN > chloroform. Overall, lignin phenols are more important as TCAA precursors than as chloroform and DCAA precursors.

This paper demonstrates that disinfection byproducts (DBP) concentration profiles in heated water were quite different from the DBP concentrations in the cold tap water. Chloroform concentrations in the heated water remained constant or even decreased slightly with increasing distribution system water age. The amount of dichloroacetic acid (DCAA) was much higher in the heated water than in the cold water; however, the maximum levels in heated water with different distribution system water ages did not differ substantially. The levels of trichloroacetic acid (TCAA) in the heated water were similar to the TCAA levels in the tap water, and a slight reduction was observed after the tap water was heated for 24 h. Regardless of water age, significant reductions of nonregulated DBPs were observed after the tap water was heated for 24 h. For tap water with lower water ages, there were significant increases in dichloroacetonitrile (DCAN), chloropicrin (CP), and 1,1-dichloropropane (1,1-DCP) after a short period of heating. Heating of the tap water with low pH led to a more significant increase of chloroform and a more significant short-term increase of DCAN. High pH accelerated the loss of the nonregulated DBPs in the heated water. The results indicated that as the chlorine doses increased, levels of chloroform and DCAA in the heated water increased significantly. However, for TCAA, the thermally induced increase in concentration was only notable for the chlorinated water with very high chlorine dose. Finally, heating may lead to higher DBP concentrations in chlorinated water with lower distribution system temperatures.

The objective of this study was to quantitatively evaluate the effect of pre-ozonation on the formation and speciation of disinfection byproducts (DBPs) from subsequent chlorination and chloramination. Laboratory experiments were conducted on six diverse natural waters with low to medium bromide concentrations. Four groups of DBPs were investigated in this study: trihalomethanes (THMs), trihaloacetic acids (THAAs), dihaloacetic acids (DHAAs), and dihaloacetonitriles (DHANs). The results showed that the relative destructions of chlorination DBP precursors by ozone generally follow the order of DHANs > THMs & THAAs > DHAAs. Pre-ozonation substantially increased the DHAA precursors in the waters with low specific ultraviolet absorbance values. Pre-ozonation shifted the formation of DBPs to more brominated species. The bromine substitution factors (BSF) of different chlorination DBPs typically increased by 1-8 percentage points after ozonation. Pre-ozonation reduced the yields of chloramination DHAAs and THMs and increased the BSFs of chloramination DHAAs by 1-6 percentage points.

A concise, rapid, and sensitive method is developed to measure organically-bound iodine in water. Total organic iodine (TOI) is used as an integrative surrogate that reflects the amount of iodinated organics in a water sample and is quantified using a refined method that builds on previous adsorption and detection approaches. The proposed method combines adsorption, combustion, and trapping of combustion products, with an offline inductively coupled plasma/mass spectrometer (ICP-MS) for iodide detection. During method development, three analytical variables (factors) were varied across two levels each in order to optimize the method for iodine recovery: 1) the sample pH prior to adsorption on the granular activated carbon (GAC); 2) the amount of base addition to the trap solution; and 3) composition of the ICP-MS wash solution. These factors were tested with solutions of eight iodinated model organic compounds, two iodinated inorganic compounds, and field water samples using a full factorial experimental design. An analysis of variance (ANOVA) and related statistical methods were deployed to identify the best combination of conditions (i.e., treatment) that results in the most complete recovery of iodine from the model compounds and the highest rejection of inorganic iodine. The chosen treatment for TOI measurement incorporates a sample pH of less than 1 prior to adsorption onto the GAC, a solution of 2% (v/v) tetramethyl ammonium hydroxide (TMAH) for trapping of combustion products, and a TMAH wash solution of 0.1% (v/v) for the ICP-MS.

Manganese is a contaminant of concern for many drinking water utilities, and future regulation may be pending. An analysis of soluble manganese (Mn(II)) oxidation by ferrate (Fe(VI)) was executed at the bench-scale, in a laboratory matrix, both with and without the presence of natural organic matter (NOM) and at two different pH values, 6.2 and 7.5. In the matrix without NOM, the oxidation of Mn(II) by Fe(VI) followed a stoichiometry of 2 mol Fe(VI) to 3 mol Mn(II). The presence of NOM did not significantly affect the stoichiometry of the oxidation reaction, indicating relative selectivity of Fe(VI) for Mn(II). The size distribution of resulting particles included significant amounts of nanoparticles. Resulting manganese oxide particles were confirmed to be MnO2 via X-ray photoelectron spectroscopy. The rate of the Mn(II) oxidation reaction was fast relative to typical time scales in drinking water treatment, with an estimated second order rate constant of approximately 1 × 10(4) M(-1) s(-1) at pH 9.2 and > 9 × 10(4) M(-1) s(-1) at pH 6.2. In general, ferrate is a potential option for Mn(II) oxidation in water treatment.

Drinking water disinfectants react with natural organic material (NOM) present in source waters used for drinking water to produce a wide variety of by-products. Several hundred disinfections by-products (DBPs) have been identified, but none have been identified with sufficient carcinogenic potency to account for the cancer risks projected from epidemiological studies. In a search for DBPs that might fill this risk gap, the present study projected reactions of chlorine and chloramine that could occur with substructures present in NOM to produce novel by-products. A review of toxicological data on related compounds, supplemented by use of a quantitative structure toxicity relationship (QSTR) program TOPKAT®) identified chemicals with a high probability of being chronically toxic and/or carcinogenic among 489 established and novel DBPs. Classes of DBPs that were specifically examined were haloquinones (HQs), related halo-cyclopentene and cyclohexene (HCP&H) derivatives, halonitriles (HNs), organic N-chloramines (NCls), haloacetamides (HAMs), and nitrosamines (NAs). A review of toxicological data available for quinones suggested that HQs and HCP&H derivatives appeared likely to be of health concern and were predicted to have chronic lowest observed adverse effect levels (LOAELs) in the low μg/kg day range. Several HQs were predicted to be carcinogenic. Some have now been identified in drinking water. The broader class of HNs was explored by considering current toxicological data on haloacetonitriles and extending this to halopropionitriles. 2,2-dichloropropionitrile has been identified in drinking water at low concentrations, as well as the more widely recognized haloacetonitriles. The occurrence of HAMs has been previously documented. The very limited toxicological data on HAMs suggests that this class would have toxicological potencies similar to the dihaloacetic acids. Organic N-halamines are also known to be produced in drinking water treatment and have biological properties of concern, but no member has ever been characterized toxicologically beyond bacterial or in vitro studies of genotoxicity. The documented formation of several nitrosamines from secondary amines from both natural and industrial sources prompted exploration of the formation of additional nitrosamines. N-diphenylnitrosamine was identified in drinking waters. Of more interest, however, was the formation of phenazine (and subsequently N-chorophenazine) in a competing reaction. These are the first heterocyclic amines that have been identified as chlorination by-products. Consideration of the amounts detected of members of these by-product classes and their probable toxicological potency suggest a prioritization for obtaining more detailed toxicological data of HQs>HCP&H derivatives>NCls>HNs. Based upon a ubiquitous occurrence and virtual lack of in vivo toxicological data, NCls are the most difficult group to assign a priority as potential carcinogenic risks. This analysis indicates that research on the general problem of DBPs requires a more systematic approach than has been pursued in the past. Utilization of predictive chemical tools to guide further research can help bring resolution to the DBP issue by identifying likely DBPs with high toxicological potency.

environmental scientists, a significant fraction of the total organic halogen (TOX) in drinking water still cannot be accounted for by known specific DBPs. The formation and control of these unknown DBPs have not been well established. The primary aim of this study was to evaluate the effect of reaction time, pH, dosage, and temperature on the formation of unknown TOX (UTOX) during chlorination and chloramination. Results showed that greater conversion of UTOX to measurable by-products occurred with increasing reaction time, pH, dose, and temperature during chlorination. The UTOX-to-TOX ratio increased with reaction time but decreased with pH and dose during chloramination. The formation of unknown brominated and iodinated DBPs decreased as chlorination or chloramination pH increased. TOX formation was significantly reduced at high pH values during chloramination. For best control of DBPs, the authors recommend that water utilities using chloramines perform chloramination under alkaline conditions. Given that dihaloacetic acids and trihaloacetic acids exhibited distinct responses to the evaluated parameters, the authors also recommend that these be considered different classes of DBPs in future studies.

The analysis of total organic halogen (TOX) in drinking water indicates that a substantial amount of the halogenated compounds cannot be accounted for by known specific disinfection by-products (DBPs). The primary aim of this research was to characterize the hydrophobicity and molecular size distribution of the unknown halogenated DBPs using XAD resins and ultrafiltration membranes. The impact of membrane rejection on the size analysis of unknown TOX was also investigated using chlorinated fulvic acid. Six finished waters from different locations and treatment processes were collected and fractionated into various hydrophobicity and molecular size groups. The results showed that most unknown TOX was in the size range between 0.5 kDa and 10 kDa, but it could have a wide spectrum of hydrophobicities. Simple ultrafiltration was not always reliable as a characterization tool, as it was shown to reject a significant fraction of DBPs with molecular weight (MW) lower than the membrane cutoffs. Flushing with deionized water was effective in removing these low MW compounds from the ultrafiltration cell. A significant reduction in the apparent size of unknown TOX resulted when low MW DBPs were flushed out of the cell (comparing with classic parallel ultrafiltration). Coagulation of fulvic acid also significantly reduced the apparent size of unknown TOX formed by chlorine.

Preventing erosion has been considered an important, pressing issue for decades. The latest techniques in conventional erosion control near wetlands use hay bales and silt fences. Although these conventional methods may reduce the amount of erosion, their effectiveness is infrequently reliable. Such methods are considered the standard means of erosion prevention in Massachusetts. Research from other states demonstrates growing interest in the use of compost for erosion control. The purpose of research was to determine the environmental acceptability of wood wastes and composted materials from various locations throughout Massachusetts to control erosion. Specific validation was done on the methodology constructed to test compost for individual analytes. Nutrient measurements consisted of total organic carbon, total nitrogen, and total phosphorus. Testing for microbial growth included enterococci and E. coli. The pH was also measured. Further assessment included a statistical analysis of the data, conducted to ensure repeatability of results from the test methods. Nine different sample locations were included in the testing. Synthetic precipitation was passed through each sample, and the effluent was collected at various time intervals. Overall, concentrations of each analyte decreased expectedly with leaching. Of note is that the average carbon–nitrogen ratio was 11:1, typical for plant organic material. Furthermore, the compost beneficially acted as a pH buffer. The repeatability of results is supportive of testing procedures, for ratios of replicate samples because both total organic carbon and total nitrogen concentrations justified a semipredictable trend despite nonquantifiable variability.

Natural organic matter (NOM) was extracted from a moderately colored, eutrophic surface water source (Forge Pond, Granby, MA), and fractionated into quasi-homogeneous fractions. Fulvic acid (FA) and hydrophilic neutrals (HN) were the two most abundant NOM fractions that were isolated. Adsorption affinity of the isolated NOM fractions on preformed aluminum hydroxide flocs increased with increase in specific organic charge of the fractions, except for the two most highly charged fractions, FA and hydrophilic acids (HAA), which showed less adsorption affinity than expected based on their specific organic charge. Prior ozonation of FA and HN fractions resulted in a decline and an increase, respectively, in their adsorption affinity on aluminum hydroxide surface. Prior ozonation of Forge Pond raw water resulted in a progressive decline in dissolved organic carbon (DOC) removal by alum coagulation with increase in ozone dose. It appeared that ozone applied to raw water reacted preferentially with the humic fraction of NOM, resulting in the detrimental effects of ozonation on subsequent NOM removal by alum coagulation being magnified. Forge Pond raw water was pre-coagulated to remove humic substances. Ozonation of the pre-coagulated water demonstrated the beneficial effects of ozonation on the removal of non-humic NOM through alum coagulation. A strategy for staged coagulation with intermediate ozonation was proposed for waters containing both humic and non-humic NOM for maximum DOC and specific UV absorbance at 254nm (SUVA) removal.

This study investigated the effectiveness of ferrate (Fe(VI)) oxidation in combination with ferric chloride coagulation on the removal of natural organic matter (NOM) and disinfection byproduct (DBP) precursors. Twelve natural waters were collected and four treatment scenarios were tested at bench-scale. Results showed that intermediate-ferrate treatment (i.e., coagulation and particle removal followed by ferrate oxidation) was most effective followed by pre-ferrate treatment (i.e., ferrate oxidation followed by coagulation and particle removal (conventional treatment)) or conventional treatment alone (i.e., no oxidation), and the least effective was ferrate oxidation alone (i.e., no coagulation). At typical doses, direct ferrate oxidation of raw water decreased DBP formation potentials (DBPFPs) by about 30% for trihalomethanes (THMs), 40% for trihaloacetic acids (THAAs), 10% for dihaloacetic acids (DHAAs), 30% for dihaloacetonitriles (DHANs), and 5% for haloketones (HKs). The formation potential of chloropicrin (CP) consistently increased after direct ferrate oxidation. Pre-ferrate followed by conventional treatment was similar to conventional treatment alone for NOM and DBP precursor removal. Ferrate pre-oxidation had positive effects on subsequent coagulation/particle removal for THM and THAA precursor removal and may allow the use of lower coagulant doses due to the Fe(III) introduced by ferrate decomposition. On the other hand, intermediate-ferrate resulted in substantially improved removal of NOM and DBP precursors, which can be attributed to initial removal by coagulation and particle removal, leaving precursors that are particularly susceptible to oxidation by ferrate. The Fe(III) resulting from ferrate decay during intermediate-ferrate process was primarily present as particulate iron and could be effectively removed by filtration.

This paper introduces the use of hierarchical Bayesian modeling as a method to estimate how kinetic properties of environmental contaminants vary across experimental factors. The hierarchical modeling framework utilizes a multilevel statistical structure, in which kinetic rate constants represent contaminant degradation behavior for individual, lower-level experiments, but also exhibit a higher-level structure across different experimental conditions. The main benefit of this modeling approach is the ability to pool information between experiments in order to reduce the influence of outliers and produce more robust predictions of degradation rate constants in an out-of-sample context. The Bayesian estimation method is also very flexible, with the ability to relax distributional assumptions on parameters, account for heteroscedasticity in model residuals, include prior information or expert knowledge when available, and propagate all uncertainties into model predictions, all with relative ease. The...