Concentrations Of Haloacetic Acids Research Articles

Formation and speciation of disinfection byproducts during chlor(am)ination of aquarium seawater

The chemistry associated with the disinfection of aquarium seawater is more complicated than that of freshwater, therefore limited information is available on the formation and speciation of disinfection byproducts (DBPs) in marine aquaria. In this study, the effects of organic precursors, bromide (Br−) and pre-ozonation on the formation and speciation of several typical classes of DBPs, including trihalomethanes (THM4), haloacetic acids (HAAs), iodinated trihalomethanes (I-THMs), and haloacetamides (HAcAms), were investigated during the chlorination/chloramination of aquarium seawater. Results indicate that with an increase in dissolved organic carbon concentration from 4.5 to 9.4mg/L, the concentrations of THM4 and HAAs increased by 3.2–7.8 times under chlorination and by 1.1–2.3 times under chloramination. An increase in Br− concentration from 3 to 68mg/L generally enhanced the formation of THM4, I-THMs and HAcAms and increased the bromine substitution factors of all studied DBPs as well, whereas it impacted insignificantly on the yield of HAAs. Pre-ozonation with 1mg/L O3 dose substantially reduced the formation of all studied DBPs in the subsequent chlorination and I-THMs in the subsequent chloramination. Because chloramination produces much lower amounts of DBPs than chlorination, it tends to be more suitable for disinfection of aquarium seawater.

Peracetic acid oxidation of saline waters in the absence and presence of H ₂O ₂: secondary oxidant and disinfection byproduct formation.

Peracetic acid (PAA) is a disinfectant considered for use in ballast water treatment, but its chemical behavior in such systems (i.e., saline waters) is largely unknown. In this study, the reactivity of PAA with halide ions (chloride and bromide) to form secondary oxidants (HOCl, HOBr) was investigated. For the PAA-chloride and PAA-bromide reactions, second-order rate constants of (1.47 ± 0.58) × 10(-5) and 0.24 ± 0.02 M(-1) s(-1) were determined for the formation of HOCl or HOBr, respectively. Hydrogen peroxide (H2O2), which is always present in PAA solutions, reduced HOCl or HOBr to chloride or bromide, respectively. As a consequence, in PAA-treated solutions with [H2O2] > [PAA], the HOBr (HOCl) steady-state concentrations were low with a limited formation of brominated (chlorinated) disinfection byproducts (DBPs). HOI (formed from the PAA-iodide reaction) affected this process because it can react with H2O2 back to iodide. H2O2 is thus consumed in a catalytic cycle and leads to less efficient HOBr scavenging at even low iodide concentrations (<1 μM). In PAA-treated solutions with [H2O2] < [PAA] and high bromide levels, mostly brominated DBPs are formed. In synthetic water, bromate was formed from the oxidation of bromide. In natural brackish waters, bromoform (CHBr3), bromoacetic acid (MBAA), dibromoacetic acid (DBAA), and tribromoacetic acid (TBAA) formed at up to 260, 106, 230, and 89 μg/L, respectively for doses of 2 mM (ca. 150 mg/L) PAA and [H2O2] < [PAA]. The same brackish waters, treated with PAA with [H2O2] ≫ [PAA], similar to conditions found in commercial PAA solutions, resulted in no trihalomethanes and only low haloacetic acid concentrations.

Reducing and verifying haloacetic acids in treated drinking water using a biological filter system

This study focused on reducing the haloacetic acid (HAA) concentrations in treated drinking water. HAA has been thought to be one possible nutrient supporting heterotrophic bacteria regrowth in drinking water. In this study, experiments were conducted using a pilot-scale system to evaluate the efficiency of biological filters (BF) for reducing excess HAA concentrations in water. The BF system reduced the total HAA concentration and the concentrations of five HAA species in the water. Dichloroacetic acid (DCAA), monobromoacetic acid (MBAA) and dibromoacetic acid (DBAA) were the three main HAA5 species that were present in the treated drinking water in this investigation. Combined, these three species represent approximately 77% of the HAA5 in the finished water after BF. The verification of the empirical HAA equation for the outlet in the BF system indicated linear relationships with high correlation coefficients. The empirical equation for the HAA5 concentrations in the finished water was established by examining other nutrients (e.g., dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm wavelength (UV254), and ammonia nitrogen) that can reduce pathogenic contamination. These findings may be useful for designing advanced processes for conventional water treatment plants or for managing water treatment and distribution systems for providing high-quality drinking water.

A fully-automated analyzer for determining haloacetic acid concentrations in drinking water

A fully-automated, on-line, real-time analyzer has been developed for preconcentration and analysis of haloacetic acids (HAAs). Preconcentration of HAAs is achieved by sample acidification and solid phase extraction onto a hydrophobic polymeric resin using sequential injection analysis (SIA). The HAAs preconcentrate is then analyzed using post-column reaction-ion chromatography (PCR-IC), which is selective for HAAs. Systematic optimization of SIA preconcentration parameters are described followed by detailed method detection limit (MDL), accuracy, precision, and linearity studies. MDL values for the individual HAA9 species range from 0.4 to 0.9μgL−1. Side-by-side comparison studies of HAAs analysis in 14 real-world drinking water samples from Alabama, Arkansas, Kentucky, Minnesota, Missouri, Mississippi, New York, Pennsylvania and Tennessee are presented that compare the optimized SIA-PCR-IC to USEPA Method 552.3. Trace levels of HAAs detected in select samples are reported, and the bias values calculated between the two methods are typically less than 5μgL−1 for eight of the nine individual HAAs.

Removal of Microcystis aeruginosa by potassium ferrate (VI): Impacts on cells integrity, intracellular organic matter release and disinfection by-products formation

Abstract Bench scale tests were conducted to study the effect of potassium ferrate (VI) on cell integrity, intracellular organic matter release and disinfection by-products formation of Microcystis aeruginosa . The simulated algal suspension was prepared a concentration of 1.0 × 10 6 cells/mL and the cytoplasmic membrane integrity was measured with flow cytometry. Results showed that a quick inactivation was achieved after ferrate (VI) oxidation, although no obvious cell lysis was observed. Intracellular organic matter (IOM) release increased with ferrate (VI) dosage and contributed to the formation of trihalomethanes (THM) and haloacetic acids (HAA) as chlorination by-products. However, enhanced coagulation of ferrate (VI) significantly removed M. aeruginosa cells and decreased the algal organic matters (AOMs). Furthermore, the concentrations of THM and HAA were reduced by 71.1% and 67.1%, respectively. Consequently, this study demonstrated potassium ferrate (VI) could act as a dual-functional chemical reagent (i.e., oxidant and coagulant) and may be potentially used in addressing the algal-rich drinking water.

Spatial and Seasonal Variations of Disinfection Byproducts (DBPs) in Drinking Water Distribution Systems of Istanbul City, Turkey

This study presents the seasonal and spatial variations of trihalomethanes (THMs) and haloacetic acids (HAAs) in 30 sampling points within three water distribution systems of Istanbul City, Turkey. The effects of surface water quality, seasonal variation, and species differences were examined. The occurrence of chlorinated THMs and HAAs levels was considerably lower in the system in which raw water is subjected to pre-ozonation versus pre-chlorination. Seasonal analysis of the data indicated that the median concentration of four THMs (THM4) was higher than nine HAAs (HAA9) concentrations in all three distribution systems sampling points. For all distribution systems monitored, the highest median THM4 and HAA9 concentrations were observed in the spring and summer season, while the lowest concentrations of these disinfection byproduct (DBP) compounds were obtained in the fall and winter period. Due to the higher level of bromide in supplying waters of these two systems, moderate levels of brominated DBP species have been observed in the Kagithane and Buyukcekmece distribution systems districts. In fact, Spearman partial correlations (Spearman rank correlation coefficients [rs]) tend to be higher among analogues in terms of number and types of substituent, especially TCAA with TCM (rs 0.91), and DBAA with DBCM (rs 0.90). In contrast, the hydraulic (residence time and flow rate) and chemical mechanisms (hydrolysis, volatilization, and adsorption) affect the fate and transport of DBPs in distribution systems. Seasonal and spatial variations of DBPs presented in this study have important implications on regulatory issues and from an epidemiological point of view.

Removal of Trihalomethanes and Haloacetic Acids from Treated Drinking Water by Biological Activated Carbon Filter

This study investigated the use of biological activated carbon filters (BACF) to reduce the amounts of disinfection by-products (DBPs) in treated drinking water in a water treatment plant. To accomplish this, experiments were conducted in a pilot-scale treatment system to evaluate the removal of trihalomethanes (THMs) and haloacetic acids (HAAs) by BACF. The results showed that BACF treatment reduced the total concentration of THMs and HAAs to meet the national drinking water standard in Taiwan. The predicted and measured values of THMs and HAAs in output water treated with a BACF showed linear relationships, with correlation coefficients (R) of 0.83 and 0.84, respectively. The results of two predictive equations of DBPs using parameters of water quality, such as total organic carbon, dissolved organic carbon, ammonia nitrogen, ultraviolet254, and total phosphorous were also established. The results of the present study can be used as a reference for water treatment plants or water distribution systems that provide drinking water.

Electrochemical removal of haloacetic acids in a three-dimensional electrochemical reactor with Pd-GAC particles as fixed filler and Pd-modified carbon paper as cathode

The reductive removal of haloacetic acids (HAAs) in a three-dimensional electrochemical continuous reactor with Pd-granular activated carbon (Pd-GAC) particles as fixed filler and Pd-modified carbon paper (Pd-C) as cathode was studied in this research. Pd-C electrode was prepared from PdCl2 via electrodeposition onto carbon paper. Pd-GAC particles were prepared by the impregnation of Pd2+ ions onto GAC. Efficient electrocatalytic reduction of HAAs in this reactor was exhibited. Effects of current density, initial HHAs concentration, and hydraulic retention time on the HHAs removal were investigated. Under the current density of 0.3 mA/cm2, HAAs with initial concentration of 120 μg/L were reduced to be less than 60 μg/L with hydraulic retention time of 20 min. Electron transfer and HAAs diffusion both played an important role in controlling the electro-reduction process under the conditions of current density less than 0.6 mA/cm2 with an initial HAAs concentration ranging from 120 to 600 μg/L. However, the HAAs diffusion became the primary rate-limiting step when the current density was higher than 0.6 mA/cm2. The Pd0 and Pd2+ species were detected by X-ray photoelectron spectroscopy. The stability of the electrochemical reactor in the reduction removal of HAAs was also exhibited.

Assessment of Haloacetic Acids in Drinking Water in Bizerte, Tunisia

An investigation into the occurrence of haloacetic acids (HAAs) was conducted during a period of winter and summer seasons of the years 2008–2009 on the drinking water of Bizerte with variable conditions of water quality, pH, water temperature, total organic carbon, and bromide concentrations. The concentrations of HAAs were determined by a fast headspace solid‐phase microextraction GC method, which consists of liquid–liquid extraction, evaporation to dryness of extraction solvent then derivatization of the HAAs to their methyl haloacetates with sulfuric acid and methanol, followed by headspace solid‐phase microextraction with GC and electron capture detection. The results of the analyses show the presence of HAAs in all chlorinated water samples. The most prevalent HAAs were trichloroacetic acid (TCAA), dichloroacetic acid (DCAA), and monochloroacetic acid (MCAA) due to the low concentrations of bromide in the water treatment plant, while other HAAs were detected at low concentrations. The annual means concentrations of TCAA, DCAA and, MCAA varied from 3.9 to 26.25 µg L−1, from 2.76 to 23.19 µg L−1, and from 6.65 to 34.07 µg L−1, respectively. Seasonal variations in HAAs were mainly linked with changes in water temperature and variations of organic precursors, with HAA occurrence at its highest in summer. In all samples the concentrations of HAAs were lower than the maximum level set by the World Health Organization except for MCAA at the network extremity. Finally, a statistically significant (p &lt; 0.05) regression analysis was used to examine the correlation of HAA5 with respect to some water quality parameters. Strong correlations between (total organic carbon, water temperature and chlorine dose) with HAA5 were observed.

Study on the TOC concentration in raw water and HAAs in Tehran’s water treatment plant outlet

A sampling has been undertaken to investigate the variation of haloacetic acids formation and nature organic matter through 81 samples were collected from three water treatment plant and three major rivers of Tehran Iran. Changes in the total organic matter (TOC), ultraviolet absorbance (UV254), specific ultraviolet absorbance (SUVA) were measured in raw water samples. Haloacetic acids concentrations were monitored using a new static headspace GC-ECD method without a manual pre-concentration in three water treatment plants. The average concentration of TOC and HAAs in three rivers and three water treatment plants in spring, summer and fall, were 4, 2.41 and 4.03 mg/L and 48.75, 43.79 and 51.07 μg/L respectively. Seasonal variation indicated that HAAs levels were much higher in spring and fall.

Effects of bromide and iodide ions on the formation of disinfection by-products during ozonation and subsequent chlorination of water containing biological source matters

This study aims to investigate the influence of the coexistence of halogen ions (bromide/iodide) and biological source matters on the speciation and yield of trihalomethanes (THMs), haloacetic acids (HAAs), and N-nitrosodimethylamine (NDMA) during the ozonation and subsequent chlorination of water. The results show that the concentrations of brominated THMs and iodinated THMs increased with increasing bromide and iodide concentration. These results may be attributed to the higher reactivity of hypobromous acid and hypoiodous acid generated from the ozonation and subsequent chlorination in the presence of bromide or iodide ions. The presence of bromide increased the species of brominated HAAs. There was a shift from chlorinated HAAs to brominated HAAs after increasing the concentration of bromide. The effect of iodide on HAA formation was more complex than bromide. For most samples, the concentration of total HAAs (T-HAAs) increased to the maximum and then decreased with increasing iodide concentration. The components of the organic precursors also significantly influenced the formation of brominated and iodinated disinfection by-products (Br-DBPs and I-DBPs). Humic acids produced more CHBr3 (596.60 μg/L) than other organic materials. Microcystis aeruginosa cells produced the most tribromoacetic acid (TBAA, 84.16 μg/L). Furthermore, the yield of NDMA decreased with increasing bromide concentration, indicating that the formation of NDMA was inhibited by the high concentration of bromide.

Association of Brominated Trihalomethane and Haloacetic Acid Exposure With Fetal Growth and Preterm Delivery in Massachusetts

We examined the relationship between adverse reproductive outcomes and exposure to several disinfection by-products including haloacetic acids (HAAs), trihalomethanes (THMs), and the brominated THMs sum (THMBr). Second- and third-trimester exposure scores were estimated from quarterly town-level average THM and HAA concentration data and were examined relative to mean birth weight (BWT), small for gestational age (SGA), and preterm delivery (PTD). We found an increased risk of PTD for second-trimester chloroform, bromodichloromethane, and all HAA exposure metrics (adjusted odds ratio range: 1.04 to 1.15), but detected no associations for SGA and third-trimester exposures. Mean BWT deficits were observed across all HAA (26 to 33 g) and THMBr (11 to 23 g) exposure categories. We detected consistent associations for adjusted mean BWT and THMBr exposures; these data reinforce the need to consider different disinfection by-product exposure metrics in epidemiological studies.

Relationships between trihalomethanes, haloacetic acids, and haloacetonitriles formed by the chlorination of raw, treated, and fractionated surface waters

This study examined effects of coagulation and fractionation of natural organic matter on the distribution of trihalomethanes (THM), haloacetic acids (HAA), and haloacetonitriles (HAN) formed in chlorinated water. The precursors of HAA and THM were determined to be associated primarily with the hydrophobic fraction although the hydrophilic fraction is important as well. On the other hand, the precursors of HAN are overwhelmingly hydrophilic with only a negligible contribution of the hydrophobic and transphilic fractions. Higher percentages of HAN were found in the treated waters compared with raw waters, collected from three different full scale water treatment plants. Very strong correlations were found between THM, HAA, and HAN concentrations. Two main correlations between THM and HAN were observed. One was applicable to all raw waters regardless of their fractionation and provenance, while the other was formed by the treated waters, again regardless of their source and fractionation. This result emphasizes that a significant removal of THM and HAA precursors can be achieved via coagulation but it results in a negligible removal of HAN precursors. As a consequence, some changes in treatment trains or operating conditions may need to be considered to minimize the formation of HAN.

Simultaneous formation and biodegradation of HAAs in slow sand filters: effects of residual chlorine in filter influent

Haloacetic acids (HAAs) are one of the major groups of chlorinated disinfection by-products in drinking water. This study explored the formation, speciation, and aerobic biodegradation of HAAs under different influent chlorine doses in batch reactor and simulated slow sand filtration (SSF) columns. The results showed that 90% of HAAs were biodegraded when no residual chlorine was present in SSF influents, and the bromine–HAAs were more biodegradable than chlorine–HAAs. In the batch systems, presence of 0.1 mg/L of free chlorine decreased both the heterotrophic plate counts and HAAs removal rates. The HAAs concentration increased predominantly when the chlorine concentration was higher than 0.5 mg/L. In the simulated labscale SSF columns, the 60 cm depth of SSF column provided the highest HAA percentage removal. When the influent chlorine concentration was higher than 0.5 mg/L, HAA formation was observed and particularly for the tri-haloacetic acids. The results of HAAs analysis in different bed depth showed that the middle and bottom sections of SSF also play an important role for HAA degradation.

Haloacetic acid degradation by a biofilm in a simulated drinking water distribution system

Haloacetic acids (HAAs) are disinfection by-products formed as a result of the reaction between chlorine and natural organic matter found in water. HAA concentrations have been observed to decrease at distribution system extremities. This decrease is associated with microbiological degradation by pipe wall biofilm. The objective of this study was to evaluate HAA degradation in a drinking water system in the presence of a biofilm and to identify the factors that influence this degradation. Degradation of dichloracetic acid (DCAA) and trichloroacetic acid (TCAA) was observed in a simulated distribution system. The results obtained showed that different parameters came into play simultaneously in the degradation of HAAs, including retention time, water temperature, biomass, composition of organic matter, and pipe diameter. Seasonal variations had a major effect on HAA degradation and biomass quantity was lower by 1 to 2 logs in the winter and spring compared with the fall. HAA removal decreased with increasingly large pipe diameters. The specific effects of each of these factors were difficult to isolate from each other owing to interactions.

Variability of chlorination by-product occurrence in water of indoor and outdoor swimming pools

Swimming is one of the most popular aquatic activities. Just like natural water, public pool water may contain microbiological and chemical contaminants. The purpose of this study was to study the presence of chemical contaminants in swimming pools, in particular the presence of disinfection by-products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs) and inorganic chloramines (CAMi). Fifty-four outdoor and indoor swimming pools were investigated over a period of one year (monthly or bi-weekly sampling, according to the type of pool) for the occurrence of DBPs. The results showed that DBP levels in swimming pools were greater than DBP levels found in drinking water, especially for HAAs. Measured concentrations of THMs (97.9 vs 63.7 μg/L in average) and HAAs (807.6 vs 412.9 μg/L in average) were higher in outdoor pools, whereas measured concentrations of CAMi (0.1 vs 0.8 mg/L in average) were higher in indoor pools. Moreover, outdoor pools with heated water contained more DBPs than unheated pools. Finally, there was significant variability in tTHM, HAA9 and CAMi levels in pools supplied by the same municipal drinking water network, suggesting that individual pool characteristics (number of swimmers) and management strategies play a major role in DBP formation.

Maternal Exposure to Drinking-water Chlorination By-products and Small-for-gestational-age Neonates

There is concern about possible effects of disinfection by-products on reproductive outcomes. The purpose of this study was to evaluate the association between maternal exposure to chlorination by-products and the risk of delivering a small for-gestational-age (SGA) neonate. We conducted a population-based case-control study in the Québec City (Canada) area. Term newborn cases with birth weights <10th percentile (n = 571) were compared with 1925 term controls with birth weights ≥10th percentile. Concentrations of trihalomethanes and haloacetic acids in the water-distribution systems of participants were monitored during the study period, and a phone interview on maternal habits was completed within 3 months after childbirth. We estimated chlorination by-products ingestion during the last trimester of pregnancy and trihalomethanes doses resulting from inhalation and dermal exposure. We evaluated associations between chlorination by-products in utero exposure and SGA by means of unconditional logistic regression with control of potential confounders. When total trihalomethanes and the 5 regulated haloacetic acids concentrations were divided into quartiles, no clear dose-response relationship was found with SGA. However, increased risk was observed when haloacetic concentrations were above the fourth quartile and when either trihalomethanes or haloacetic acids concentrations were above current water standards (adjusted OR= 1.5 [95% confidence interval = 1.1-1.9] and 1.4 [1.1-1.9], respectively). Inhalation and dermal absorption of trihalomethanes did not contribute to this risk, but a monotonic dose-response was found with haloacetic acids ingestion. Oral exposure to high levels of chlorination by-products in drinking water could be a risk factor for term SGA.

Analysis of haloacetic acids in water and air (aerosols) from indoor swimming pools using HS-SPME/GC/ECD

A solid phase microextraction method was used for the analysis of nine haloacetic acids (HAAs) in water and air (aerosols) from indoor swimming pools (ISPs). The analysis is characterized by derivatization of HAAs to their methyl-esters with dimethyl sulphate, headspace solid phase microextraction (HS-SPME) with a Carboxen–polydimethylsiloxane (CAR-PDMS) fiber and gas chromatography - electron capture detector (GC/ECD). High correlation coefficients were obtained for esters mixture calibration lines and detection limits were found to be at the low ppb level. Repeatability was assessed and coefficients of variation varied from 10 to 20%. Reproducibility was also evaluated and coefficients of variation from 15 to 25% were obtained. Analytical results from four Portuguese ISPs showed that the mean concentration of total HAAs (THAAs) in water ranged from 10 ± 2 to 183 ± 28 μg/L in which 55 ± 20% corresponded to trichloroacetic and dichloroacetic acids (TCAA and DCAA). THAAs highest concentrations were directly related to higher ISPs’ water organic matter content. In the lack of European specific regulation for water from ISPs and taking into consideration that ingestion is a form of exposure, THAAs concentration values were compared with drinking water maximum contamination level (MCL) of 60 μg/L proposed by the US EPA for the sum of five HAAs. In 35% of water sampling campaigns the sum of MBAA (monobromoacetic acid), MCAA (monochloroacetic acid), DCAA and TCAA exceeded that MCL value. The concentrations obtained for THAAs in the ISPs’ atmosphere ranged from 5 ± 1 to 64 ± 10 μg/m3 (T = 28°C at 5 cm above the water surface) and were proportional to the aerosols’ quantity, which was deeply related to indoor air ventilation system.

Modeling of THMs and HAAs Formation in Distribution System upon Chlorination

Seasonal variations of trihalomethanes (THMs) and haloacetic acids (HAAs) were investigated within distribution systems of the Yangtze river treatment plant in Nanjing City (China).The investigation was based on one year sampling program, undertaken from the fall and winter of the year 2007 to the spring and summer of the year 2008. A multiple linear regression model was developed to predict THMs and HAAs concentrations in distribution water. Routinely measured parameters including free residual chlorine, ultraviolet light absorbance at 254 nm (UV254), temperature, pH and NH3-N in distribution water was used to develop the model for the prediction of THMs and HAAs. The developed models provided satisfactory estimations of the concentrations of THMs and HAAs and the model regression coefficients of THMs and HAAs are 0.90 and 0.87, respectively. Further, the Durbin-Watson values confirm the reliability of the two models. The results indicate that variations of free residual chlorine, ultraviolet light absorbance at 254 nm (UV254), temperature, pH and NH3-N can described the formation of THMs and HAAs in distribution water by the multiple linear regression technique.

Modeling of THMs and HAAs Formation in Distribution System upon Chlorination

Seasonal variations of trihalomethanes (THMs) and haloacetic acids (HAAs) were investigated within distribution systems of the Yangtze river treatment plant in Nanjing City (China).The investigation was based on one year sampling program, undertaken from the fall and winter of the year 2007 to the spring and summer of the year 2008. A multiple linear regression model was developed to predict THMs and HAAs concentrations in distribution water. Routinely measured parameters including free residual chlorine, ultraviolet light absorbance at 254 nm (UV254), temperature, pH and NH3-N in distribution water was used to develop the model for the prediction of THMs and HAAs. The developed models provided satisfactory estimations of the concentrations of THMs and HAAs and the model regression coefficients of THMs and HAAs are 0.90 and 0.87, respectively. Further, the Durbin-Watson values confirm the reliability of the two models. The results indicate that variations of free residual chlorine, ultraviolet light absorbance at 254 nm (UV254), temperature, pH and NH3-N can described the formation of THMs and HAAs in distribution water by the multiple linear regression technique.