Occurrence of haloacetic acids (HAAs) and trihalomethanes (THMs) in drinking water of Taiwan

In this study, water samples were collected from 86 water treatment plants for analysis of haloacetic acids (HAAs) and trihalomethanes (THMs) from February to March, 2007 and from July to August, 2007. Both seasonal and geographical variations of disinfection by-products (DBPs) in drinking water of Taiwan were presented. The results showed that the five HAA concentrations (HAA5) were 1.0–38.9 μg/L in the winter and 0.2–46.7 μg/L in the summer; and the total THMs were ND-99.4 μg/L in the winter and ND-133.2 μg/L in the summer. For samples taken from the main Taiwan island, dichloroacetic acid (29.4–31.7%) and trichloroacetic acid (25.3–27.6%) were the two major HAA species, and trichloromethane was the major THM species (49.9–62.2%) in finished water. For water treatment plants located on the offshore islands outside of Taiwan, high bromide concentration was found in raw water, and higher percentage of brominated THMs and HAAs were formed in the overall formation. A statistically significant (P?<?0.005) logarithmic linear regression model was found to be useful to describe the correlations between TTHM and HAA5 or nine HAAs (HAA5?=?1.219 ×TTHM ^0.754, R ²?=?0.658; HAA9?=?1.824 ×TTHM ^0.735, R ²?=?0.678). No apparent difference was observed for DBPs concentrations between finished water and distribution samples in this study.     

Risk assessment of trihalomethanes from tap water in Fortaleza, Brazil

The cancer risks (CR) by oral ingestion, dermal absorption, and inhalation exposure of trihalomethanes (THM) from tap water of ten districts in Fortaleza, Brazil were estimated. The mean levels of THM compounds were obtained in Fortaleza tap water as follow: 63.9 microg L(-1) for chloroform (CHCl(3)), 40.0 microg L(-1) for bromodichloromethane (CHBrCl(2)), and 15.6 microg L(-1) for dibromochloromethane (CHBr(2)Cl). Bromoform (CHBr(3)) was not detected. The mean CR for THMs in tap water is 3.96 x 10(-4). The results indicate that Fortaleza residents have a higher CR by inhalation than dermal absorption and oral ingestion. The CR for CHCl(3) contributes with 68% as compared with the total CR, followed by CHBrCl(2) (21%), and CHBr(2)Cl (11%). The hazard index (HI) is about ten times lower than unity, not indicating non-cancer effects.     

Disinfection By-Products in Water Produced by Ozonation and Chlorination

Water produced by advanced treatment of a groundwater was evaluated to determine the amount of DBPs (Disinfection By-Products) including trihalomethanes (THMs). Both Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GS/MS) were adopted for detection and identification of DBPs such as trihalomethanes (THMs), halo-acetic acids (HAAs) and aldehydes. Two disinfection modes (ozonation followed by chlorination and chlorination alone) were compared to determine the DBPs generation. The mutagenitic acivity of ozonated water, chlorinated water after ozonation and potable water was assessed using the Ames test. Chloroform, dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) were the main constituents of THMs and HAAs, respectively. THMs accounted for more than 85% of all DBPs measured, whereas haloacetic acids accounted for around 14%. Ozonation followed by chlorination proved to be better in terms of THMs and HAAs control. The combined system produced 28.3% less DBPs compared to chlorination alone. Ozonation was found capable of reducing mutagenic matter in the groundwater by 54.7%. The combined system also resulted in water with no mutagenicity.     

Hydrogen Peroxide and Ultraviolet Irradiations in Water Treatment

Trihalomethanes (THMs) the by-products of chlorination in water treatment are recognised as a threat to public health due to their carcinogenicity. The photodegradation of THMs using hydrogen peroxide has been found to give increased removal efficiency and the outcome of the study may find, its application in designing a unit process for water treatment. Batch experiments were carried out using UV lamp of 83 W and 40% w/w Hydrogen peroxide (H₂O₂) in test waters between 2.5–10 pH range of chloroform, bromodichloromethane, dibromochloromethane and bromoform at 50–200 μg L⁻¹ initial concentration. 92–100% removal of chloroform, bromodichloromethane, dibromochloromethane and bromoform were found with 0.1% of H₂O₂ and 90 min of UV exposure.     

Environmental assessment of 2-mercaptobenzimidazole based on the surface plasmon resonance band of gold nanoparticles

A colorimetric assay method is described for the environmental detection of 2-mercaptobenzimidazole (MBI) using surface plasmon resonance of gold nanoparticles (AuNPs). Stable and dispersed AuNPs with intensified plasmon resonance were prepared in situ using a simple, rapid, and eco-friendly procedure by applying ascorbic acid as a reducer and cetyltrimethylammonium bromide as a stabilizer. The presence of MBI has a strong effect on the plasmon absorbance of AuNPs, which was employed for the detection of MBI. The calibration curve was linear in the range of 1.0?×?10^?6–5.5?×?10^?5 mol/L of MBI; the detection limit was 8.4?×?10^?7 mol/L. The relative standard deviations for eight replicate measurements of 3.0?×?10^?6 and 5?×?10^?5 mol/L MBI were 3.9 and 1.4 %, respectively. The method was successfully applied to the determination of MBI in tap, river, sea, and heat exchanger cooling water samples.     

High potential for the formation of haloacetic acids in the Karoon River water in Iran

The impact of the total organic carbon (TOC), chlorine dosage, water temperature, reaction time, pH, and seasonal variation on the formation of haloacetic acids (HAAs) in the Karoon River in Iran was studied. The results showed that dichloroacetic acid and trichloroacetic acid were the most detected HAA₅. The HAA₅ formation potential (HAA₅FP) levels in the Karoon River water in spring time, when the water TOC content exceeded 4 mg/L, were 1.38 times higher than during the winter season, when the water TOC content was below 3.5 mg/L. There was not a strong correlation between the HAA₅FP and the residence time for the Karoon River water. For the range of the water temperatures studied, there was little variation in the HAA₅FP in cold water, but in warmer water, the values of the HAA₅FP varied quickly.     

Comparative cancer risk assessment of THMs in drinking water from well water sources and surface water sources

This research evaluates the lifetime cancer risks from trihalomethanes in Tehran's drinking water. The Trihalomethanes were measured in seven different water districts. Sixty-three samples were taken from tap water across the city for 7 months. The samples were analyzed for trihalomethanes using US EPA method 524.2. The average concentration of total trihalomethanes in different districts were between 0.81 and 9.0 μg/L, and the highest concentrations were detected in district 2 at 19.5 μg/L. Total lifetime cancer risks assessment from exposure to trihalomethanes in drinking water (ingestion, inhalation, and skin routes) were performed for people living in different districts in Tehran. The lifetime cancer risk was 7.19 × 10(-5) in district 2 (a more affluent neighborhood) where mostly surface water sources is used to supply drinking water and 9.38 × 10(-6) in district 7 (a less affluent neighborhood) which is mainly supplied with well water sources. Based on the population data, the total expected lifetime cancer cases from exposure to trihalomethanes are 104, 108, 81, 81, 41, 27, and three for districts 1 through 7, respectively. The average lifetime cancer risk was 4.33 × 10(-5) which means a total of 606 lifetime cancer cases for the entire province of Tehran. The highest risk from THMs seems to be from the inhalation route followed by ingestion and dermal contacts.     

Multi-level modelling of chlorination by-product presence in drinking water distribution systems for human exposure assessment purposes

During drinking water treatment and distribution, chlorine reacts with organic matter occurring in water to form various chlorination by-products (CBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). This paper presents the occurrence of THMs and HAAs in different water distribution systems (DS) of the same region and their modelling for exposure assessment purposes. This study was conducted in eight DS supplying chlorinated water to the population of Québec City, Canada. These systems differ in type of water source (i.e. surface, ground or mixed water), in treatment applied at the plant, and in size and structure of the DS. Two spatio-temporal databases for THMs and HAAs were implemented, one for model development and the other for model validation. The analysis of the data demonstrates significant seasonal and spatial variations of these compounds. A multi-level statistical modelling approach was applied to estimate the ranges for occurrence of THMs and HAAs in the eight DS (i.e. a single model for the study region for each CBP species). The modelling approach integrates available or easily measurable parameters. For both THMs and HAAs, a two-level model considering a sampling-site random effect was selected among various models initially developed. The model capacity for estimating the presence of THMs and HAAs in drinking water and its usefulness for exposure assessment purposes in the studied region was demonstrated.     

Human health damage caused by particulate matter PM10 and ozone in urban environments: the case of Athens, Greece

Studies conducted over the past decades have provided substantial evidence that both the long- and the short-term exposures to ozone and particulate matter are responsible for mortality and cardiopulmonary morbidity. This paper examines the relationship between exposure to ambient concentrations of ozone (O₃) and particulate matter with aerodynamic diameter of less than 10 μm (PM₁₀) and public health and provides the quantification of the burden of disease from PM₁₀ and O₃-related mortality and morbidity through a Life Cycle Impact Assessment focused on the greater area of Athens, Greece. Thus, characterizations factors (CFs) for human health damage are calculated in 17 sites in Athens, in terms of the annual marginal change in the disability-adjusted life years (DALYs) due to a marginal increase in the ambient concentrations. It is found that the PM₁₀ intake factors range between 1.25?×?10^?6 and 2.78?×?10^?6, suggesting that 1.25–2.78 μg of PM₁₀ are inhaled by the Athenian population per kg of PM₁₀ in the urban atmosphere. Mortality due to chronic exposure to PM₁₀ has a dominant contribution to years of life lost with values ranging between 6.2?×?10^?5 and 1.1?×?10^?4. On the other hand, the mortality caused by short-term exposure to O₃ is weaker with the CFs ranging between 1.58?×?10^?7?years of life lost in the urban/traffic areas and 4.71?×?10^?7?years in the suburbs. Finally, it is found that 9,000 DALYs are lost on average in Athens, corresponding to 0.0018 DALYs per person. This is equal to 0.135 DALYs per person over a lifetime of approximately 75 years, assuming constant emission rates for the whole period.     

A nanosilver-based spectrophotometric method for determination of malachite green in surface water samples

A new spectrophotometric method is reported for the determination of nanomolar level of malachite green in surface water samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of malachite green by hexacyanoferrate (III) in acetate–acetic acid medium. The absorbance is measured at 610 nm with the fixed-time method. Under the optimum conditions, the linear range was 8.0?×?10^?9–2.0?×?10^?7?mol?L^?1 malachite green with a correlation coefficient of 0.996. The limit of detection (S/N?=?3) was 2.0?×?10^?9?mol?L^?1. Relative standard deviation for ten replicate determinations of 1.0?×?10^?8?mol?L^?1 malachite green was 1.86 %. The method is featured with good accuracy and reproducibility for malachite green determination in surface water samples without any pre-concentration and separation step.     

New kinetic-spectrophotometric method for monitoring the concentration of iodine in river and city water samples

A new kinetic method has been developed for the determination of iodine in water samples. The method is based on the catalytic effect of I^? with the oxidation of Indigo Carmine (IC) by KBrO₃ in the sulfuric acid medium. The optimum conditions obtained are 0.16 M sulfuric acid, 1?×?10^?3 M of IC, 1?×?10^?2 M KBrO₃, reaction temperature of 35°C, and reaction time of 80 s at 612 nm. Under the optimized conditions, the method allowed the quantification of I^? in a range of 12–375 ng/mL with a detection limit of 0.46 ng/mL. The method was applied to the determination of iodine in river and city water samples with the satisfactorily results.     

Formation and modeling of disinfection by-products in drinking water of six cities in China

Water quality parameters including TOC, UV(254), pH, chlorine dosage, bromide concentration and disinfection by-products were measured in water samples from 41 water treatment plants of six selected cities in China. Chloroform, bromodichloromethane, dibromochloromethane, dichloroacetic acid and trichloroacetic acid were the major disinfection by-products in the drinking water of China. Bromoform and dibromoacetic acid were also detected in many water samples. Higher concentrations of trihalomethanes and haloacetic acids were measured in summer compared to winter. The geographical variations in DBPs showed that TTHM levels were higher in Zhengzhou and Tianjin than other selected cities. And the HAA5 levels were highest in Changsha and Tianjin. The modeling procedure that predicts disinfection by-products formation was studied and developed using artificial neural networks. The performance of the artificial neural networks model was excellent (r > 0.84).     

Utility of cefixime as a complexing reagent for the determination of Ni(II) in synthetic mixture and water samples

A simple, sensitive, and accurate UV spectrophotometric method has been developed for the determination of nickel in synthetic mixture and water samples. The method is based on the complexation reaction of nickel ion with cefixime, thus leading to the formation of Ni–cefixime complex in ethanol-distilled water medium at room temperature. The complex showed the maximum absorption wavelength at 332 nm. Beer’s law is obeyed in the working concentration range of 0.447–4.019 μg?mL^?1 with apparent molar absorptivity of 7.314?×?10³?L?mol^?1?cm^?1 and Sandell’s sensitivity of 0.008 μg/cm²/0.001 absorbance unit. The limits of detection and quantitation for the proposed method are 0.016 and 0.054 μg?mL^?1, respectively. The factors such as cefixime concentration and solvent affecting the complexation reaction were carefully studied and optimized. The method is validated as per the International Conference on Harmonisation guideline. The method is successfully applied to the determination of Ni(II) in synthetic mixture and wadi water samples collected from Al Rustaq. The same water samples are also analyzed by atomic absorption spectrophotometry. Both methods determined the amount of Ni(II) in water sample and found to be approximately the same.     

Bioaccumulation and toxicity of arsenic in cyanobacteria cultures separated from a eutrophic reservoir

The bioaccumulation and toxicity of arsenate (arsenic (As)(V)) was studied using three cultures of cyanobacterial species—Oscillatoria tenuisa, Anabaena affinis, and Microcystis aeruginosa—that were isolated from a eutrophic reservoir. The As(V) uptake depended on the cyanobacterial species, the growth phase of the cyanobacteria, the duration of exposure, and the initial concentration of As(V). The specific growth rates of the three cultures immediately following the logarithmic phase were 0.033–0.041 L/day when the initial concentration of As(V) was 50 mg/L. These rates were 2.3–3.6 times less than those in the original culture medium without As(V). The rate of intake of As(V) in the logarithmic phase cultures greatly exceeded that in the stationary cultures. The accumulation of As(V) by the three cultures increased rapidly within 1 week from the initial value of 3.23?×?10^?2–5.40?×?10^?2 to 5.06?×?10^?1–6.73?×?10^?1 ng/cell in the logarithmic phase. The effective concentrations (EC₅₀) of As(V) for inhibiting the growth of the three cyanobacterial species growth of at 72 h followed the order Oscillatoria tenuisa (3.8 mg/L)?>?A. affinis (2.6 mg/L)?>?M. aeruginosa (1.2 mg/L). The cyanobacterial species that was most sensitive to As(V) was M. aeruginosa. Preliminary results from SEM-map studies suggest most of the As(V) in Microcystis aeruginosa accumulated in the cytoplasm (intercellular), while in O. tenuisa and A. affinis, a large proportion of As(V) bound to the cell wall (extracellular). These differences were understood with reference to the variation among the metabolic properties and morphological characteristics of the cyanobacterial species.     

Study of personal–indoor–ambient fine particulate matters among school communities in mixed urban–industrial environment in India

A sampling program was conducted to investigate the formation of disinfection by-products (DBPs) and dissolved organic carbon (DOC) at two advanced water treatment plants in Kaohsiung City, Taiwan. The results in this study can be used as a reference for the operational control of water treatment plants and the setting of regulations in Taiwan. Samples of drinking water were collected from two advanced water treatment plants from June 2007 to April 2008. Changes in the concentration of dissolved organic carbon, the trihalomethane formation potential, and the haloacetic acids formation potential were measured in raw water samples. Variations in the concentrations of trihalomethanes (THMs) and haloacetic acids (HAA₅) in finished drinking water were evaluated. The major species of HAA₅ were in the order of dichloroacetic acid and trichloroacetic acid and the THM was of trichloromethane. DOC was strongly related to DBPs in raw water. In this investigation, the removal efficiency of DBPs in Plant A (ultrafiltration/reverse osmosis system) exceeded that in Plant B (ozonation/biological activated carbon system). Both advanced water treatment plants greatly improved the quality of drinking water.     

Evaluation of concentration efficiency of the Pseudomonas aeruginosa phage PP7 in various water matrixes by different methods

Enteric viruses monitoring in surface waters requires the concentration of viruses before detection assays. The aim of this study was to evaluate different methods in terms of recovery efficiencies of bacteriophage PP7 of Pseudomonas aeruginosa, measured by real-time PCR, using it as a viral control process in water analysis. Different nucleic acid extraction methods (silica–guanidinium thiocyanate, a commercial kit (Qiagen Viral RNA Kit) and phenol–chloroform with alcohol precipitation) exhibited very low recovery efficiencies (0.08–4.18 %), being the most efficient the commercial kit used for subsequent experiments. To evaluate the efficiency of three concentration methods, PBS (as model for clean water) and water samples from rivers were seeded to reach high (HC, 10⁶ pfu ml^?1) and low concentrations (LC, 10⁴ pfu ml^?1) of PP7. Tangential ultrafiltration proved to be more efficient (50.36?±?12.91, 17.21?±?9.22 and 12.58?±?2.35 % for HC in PBS and two river samples, respectively) than adsorption–elution with negatively charged membranes (1.00?±?1.34, 2.79?±?2.62 and 0.05?±?0.08 % for HC in PBS and two river samples, respectively) and polyethylene glycol precipitation (15.95?±?7.43, 4.01?±?1.12 and 3.91?±?0.54 %, for HC in PBS and two river samples, respectively), being 3.2–50.4 times more efficient than the others for PBS and 2.7–252 times for river samples. Efficiencies also depended on the initial virus concentration and aqueous matrixes composition. In consequence, the incorporation of an internal standard like PP7 along the process is useful as a control of the water concentration procedure, the nucleic acid extraction, the presence of inhibitors and the variability of the recovery among replicas, and for the calculation of the sample limit of detection. Thus, the use of a process control, as presented here, is crucial for the accurate quantification of viral contamination.     

Effect of citric acid on metals mobility in pruning wastes and biosolids compost and metals uptake in <Emphasis Type="Italic">Atriplex halimus</Emphasis> and <Emphasis Type="Italic">Rosmarinus officinalis</Emphasis>

To assess metal mobility in pruning waste and biosolids compost (pH?6.9 and total concentration of metals in milligram per kilogram of Cd 1.9, Cu 132, Fe 8,513, Mn 192, Pb 81, and Zn 313), shrubs species Atriplex halimus and Rosmarinus officinalis were transplanted in this substrate and irrigated with citric acid (4 g?L^?1, pH?2.9) and nutrient solution daily for 60 days. Citric acid significantly increased the concentrations of soluble Mn and Fe in the nutrient substrate solution measured by suction probes, while other metals did not vary in concentration (Cu and Zn) or were not observed at detectable levels (Cd and Pb). In plants, citric acid significantly increased the concentrations of Cu (2.7?±?0.1–3.3?±?0.1 mg?kg^?1), Fe (49.2?±?5.2–76.8?±?6.8 mg?kg^?1), and Mn (7.2?±?1.1–11.4?±?0.7 mg?kg^?1) in leaves of R. officinalis, whereas the concentration of only Mn (25.4?±?0.3–42.2?±?2.9 mg?kg^?1) was increased in A. halimus. Increasing Fe and Mn solubility by citric acid addition indicates the possibility of using it to improve plant nutrition. The mobility of metals in this substrate was influenced for the concentration of the metal, the degree of humification of organic matter and its high Fe content.     

Determination of hydrazine hydrate based on electrochemiluminescence of Ru(bpy) 3 2+

Considering of the basic properties and also the two nitrogen atoms in the structure, hydrazine hydrate was employed to be an amine additive candidate, to build a Ru(bpy) ₃ ²⁺ /hydrazine electrochemiluminescence (ECL) system, and ECL of Ru(bpy) ₃ ²⁺ has been employed for the determination of hydrazine hydrate in the paper. The result demonstrated that the logarithmic ECL increasing (ΔECL?=?ECL_{after addition of hydrazine}???ECL_{before addition of hydrazine}) versus the logarithmic concentration of hydrazine hydrate is linear over a concentration range of 1.0?×?10^?9 to 1.0?×?10^?5?mol/L, on both glassy carbon and Pt electrodes in a pH 9 phosphate buffer. The hydrazine hydrate detection limit was down to 1.0?×?10^?9?mol/L, comparatively lower than other detection methods. To check its applicability, the proposed method was applied to the determination of hydrazine hydrate added into a tap water sample with good reproducibility and stability. All these provide a possibility to develop a novel ECL detection method for hydrazine in water.     

Monitoring the Trihalomethanes Present in Water After Treatment with Chlorine Under Laboratory Condition

In this work assays involving chlorinated water samples, which were previous spiked with humic substances or algae blue green and following the production of the THMs for 30 days is described. To implement the assays, five portions of 1,000 ml of water were stored in glass bottles. The water samples were treated with solutions containing 2, 3, 4 and 5 mg l⁻¹ chlorine. The samples aliquots (60 ml) were transferred into the glass vials, 10 ml were removed to have a headspace and 100 μl of the 10 mg l⁻¹ pentafluortoluene bromide solution was added to each vial. The extraction step was performed by adding 10 g of Na₂SO₄ followed by 5 ml of n-pentane. The vials were stopped with a TFE-faced septum and sealed with aluminum caps. The generated THMs were determined by gas chromatography with electron capture detector using reference solutions with concentration ranging from 8 to 120 μg l⁻¹ THMs. Three assays were monitored during 30 days and chloroform was the predominant compound found in the water samples, while other species of THMs were not detected. The results showed that when the chlorine concentration was increased in water samples containing algae the concentration of THM varied randomly. Nevertheless, in water samples containing humic substances the increase of the THM concentration presented a relationship with the chlorine concentration. It was also observed that chloroform concentration increased with the elapsed time up to one and six days to water samples spiked with humic substances and algae blue green, respectively and decreased along 30 days. By other hand, assays performed using water samples containing decanted algae material showed that THM was not generated by the chlorine addition.     

Groundwater quality assessment in the urban-west region of Zanzibar Island

This paper highlights the levels of anions (nitrate, nitrite, sulfate, bromide, chloride, and fluoride) and cations (potassium, sodium, magnesium, and calcium) in selected springs and groundwater sources in the urban-west region of Zanzibar Island. The levels of total dissolved solids (TDS) and sodium adsorption ratio (SAR) were also studied. Thirty water samples were collected in December 2012 from various types of water sources, which included closed hand-dug wells (CHDW), open hand-dug wells (OHDW), springwater (SW), public bore wells (PBW), and bore wells owned by private individuals (BWP), and analyzed after filtration and sometimes dilution. The cations were analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES). The anions were analyzed by chemically suppressed ion chromatography (IC). The ranges of the levels of the investigated parameters were as follows: Na 13.68–3,656 mg L^?1, K 2.66–583 mg L^?1, Mg 0.63–131.10 mg L^?1, Ca 16.79–189.9 mg L^?1, Cl^? 8.61–4,340.97 mg L^?1, F^? 0–1.02 mg L^?1, Br^? 0–10.88 mg L^?1, NO₃ ^? 0.18–342.4 mg L^?1, NO₂ ^? 0–1.39, SO₄ ^2? 4.43–534.02 mg L^?1, TDS 7–6,380 mg L^?1, and SAR 0.63–50. Except fluoride, most of the studied parameters in the water samples had concentrations beyond the permissible limits of the World Health Organization (WHO). The elevated concentrations are a result of seepage of contaminated water from on-site septic tanks, pit latrines, landfill leachates, fertilizer applications, and domestic effluents. These results should alert domestic water stakeholders in Zanzibar to the urgent task of initiating a quick mitigation response to control these alarming water risks.