Trihalomethanes Compounds Research Articles

Occurrence and Risk Assessment of Trihalomethans in Al-Hilla Drinking Water Plant

Trihalomethanes (THMs) have been assessed as potentially carcinogenic for humans and pose a hazard index for drinking water samples. Three water samples were collected namely - raw water, chlorinated water, and drinking water at the central drinking water plant in Babylon province. These samples were analyzed using Gas Chromatography to determine monthly variations in the levels of THM compounds, including Chloroform, Dibromochloromethane, Bromodichloromethane, and Bromoform. The concentrations varied, with high and low values: Chloroform (17.58, 0.47 μg/l), Dibromochloromethane (7.65, 0.08 μg/l), Bromodichloromethane (4.0, 0.03 μg/l), and Bromoform (0.89, 0.15 μg/l) in chlorine basin and supply pipes during the summer and winter months, respectively. A general pattern in the distribution of trihalomethane compounds at all sites was observed: Chloroform (51%) > Bromodichloromethane (21%) > Bromoform (17%) > Dibromochloromethane (11%). During May and June, the ingestion risks for Chloroform and overall THMs surpassed US EPA guidelines. This information is vital for Babylon water authorities assessing water quality’s health implications.

Comparison of Anolyte and Chlorine Dioxide for a Continuous Hot Water Disinfection in Nursing Home: A Two Years Legionnaires’ Disease Prevention

Worldwide epidemiological reports assert that drinking water is a source for infections and Legionella control represents a critical issue in healthcare settings. Chemical disinfections of water networks are control measures that need to be fine-tuned to obtain satisfactory results in large buildings over prolonged time periods. Aim of study is the evaluation of the effect of anolyte and chlorine dioxide, applied in two different hot water networks of a nursing home to manage Legionella risk. Nursing home has two buildings (A and B), with the same point of aqueduct water entrance. From June 2016, following a shock chlorination, the continuous disinfections with chlorine dioxide and anolyte were applied in hot networks of building A and B, respectively. Hot water was sampled at the central heating system and at two points of use for Legionella research, while chemical tests of manganese (Mn), iron (Fe), zinc (Zn) and trihalomethanes compounds (THM) were implemented to evaluate the disinfection by-products presence. Before chlorination Legionella pneumophila sg1 was recovered with a mean count of 2.4 × 104 CFU/L, while chemical compounds concentrations were within the law limits (Directive 98/83/EC). Then the disinfections Legionella was not recovered in both hot water plants. After the disinfection with chlorine dioxide (from June 2016 to May 2018), a statistically significant increase of iron, zinc and THM concentrations was detected in building A (p = 0.012; p = 0.004; p = 0.008). Both disinfectants appear effective against Legionella spp. growth in water network, but anolyte ensures a lower disinfection by-products release.

Evaluation of Human Health Risks Associated with Exposure to Disinfection by-Products (Dbps) in Drinking Water of Wassit Province Southeast Iraq

The toxicological risks and lifetime cancer risks associated with exposure to disinfection by-products (DBPs) including Halloacetic acids (HAAs) and trihalomethanes (THMs) compounds by drinking water in several districts in Wassit Province were estimated. The seasonal variation of HAAs and THMs compounds in drinking water have indicated that the mean values for total HAAs (THAAs) and total THMs (TTHMs) ranged from 43.2 to 72.4 mg/l and from 40 to 115.5 mg/l, respectively. The World health organization index for additive toxicity approach was non-compliant with the WHO guideline value in summer and autumn seasons and this means that THMs concentration has adverse toxic health effects. The multi-pathway of lifetime human health risk of cancer credited to THMs and HAAs in drinking water via three exposure routes for THMs and only one exposure route for HAAs was evaluated and found to be 6.13×10-4 and 1.78×10-4 respectively and these values were higher than the US.EPA range of concern limit of 1×10-6. The risk ratio of THAAs to TTHMs was 3.44. Also, the highest cancer risk was recorded for BDCM followed by DBCM, CF, TCAA, DCAA, and BF.

Evaluation of Human Health Risks Associated with Exposure to Disinfection by-Products (Dbps) in Drinking Water of Wassit Province Southeast Iraq

The toxicological risks and lifetime cancer risks associated with exposure to disinfection by-products (DBPs) including Halloacetic acids (HAAs) and trihalomethanes (THMs) compounds by drinking water in several districts in Wassit Province were estimated. The seasonal variation of HAAs and THMs compounds in drinking water have indicated that the mean values for total HAAs (THAAs) and total THMs (TTHMs) ranged from 43.2 to 72.4 mg/l and from 40 to 115.5 mg/l, respectively. The World health organization index for additive toxicity approach was non-compliant with the WHO guideline value in summer and autumn seasons and this means that THMs concentration has adverse toxic health effects. The multi-pathway of lifetime human health risk of cancer credited to THMs and HAAs in drinking water via three exposure routes for THMs and only one exposure route for HAAs was evaluated and found to be 6.13×10-4 and 1.78×10-4 respectively and these values were higher than the US.EPA range of concern limit of 1×10-6. The risk ratio of THAAs to TTHMs was 3.44. Also, the highest cancer risk was recorded for BDCM followed by DBCM, CF, TCAA, DCAA, and BF.

Removal of humic acid from aqueous solution using photocatalytic reaction on perlite granules covered by Nano TiO2 particles

Humic acid (HA) constitutes a large portion of natural organic matter (NOM), and is the main precursor of toxic and cancerogenic Trihalomethanes compounds, formed during chlorination of drinking water. Therefore, it is essential that the humic acid be eliminated from water before treating it.The present study aims to investigate the photocatalytic degradation of humic acid (HA) using TiO2 nanoparticles immobilized on perlite granules (TIP), irradiated by UV light in a photoreactor. Samples of coated perlites were prepared by a dip coating method using a commercial powder of TiO2. Characteristics of the prepared samples were evaluated by X-ray and scanning electron microscope techniques. Results showed no significant changes in the structure of TiO2 and a relative uniform morphology was observed on the TIP. HA concentration was determined by spectrophotometry at a wavelength of 254nm using a calibration curve. The effect of some parameters such as pH, additional oxidizer, initial concentration of HA, and light intensity were investigated. Results showed that TIP could degrade a significant amount of HA in a relatively long time.The best result obtained from the experiment was a 98% degradation gained at an initial concentration of 2mg/L of HA, under the initial condition of pH=4 and 20mg/L of H2O2 in 120min. TIP can be a practical way to degrade HA from water.

Influence of physical activity in the intake of trihalomethanes in indoor swimming pools

This study describes the relationship between physical activity and intake of trihalomethanes (THMs), namely chloroform (CHCl3), bromodichloromethane (CHCl2Br), dibromochloromethane (CHClBr2) and bromoform (CHBr3), in individuals exposed in two indoor swimming pools which used different disinfection agents, chlorine (Cl-SP) and bromine (Br-SP). CHCl3 and CHBr3 were the dominant compounds in air and water of the Cl-SP and Br-SP, respectively. Physical exercise was assessed from distance swum and energy expenditure. The changes in exhaled breath concentrations of these compounds were measured from the differences after and before physical activity.A clear dependence between distance swum or energy expenditure and exhaled breath THM concentrations was observed. The statistically significant relationships involved higher THM concentrations at higher distances swum. However, air concentration was the major factor determining the CHCl3 and CHCl2Br intake in swimmers whereas distance swum was the main factor for CHBr3 intake. These two causes of THM incorporation into swimmers concurrently intensify the concentrations of these compounds into exhaled breath and pointed to inhalation as primary mechanism for THM uptake. Furthermore, the rates of THM incorporation were proportionally higher as higher was the degree of bromination of the THM species. This trend suggested that air–water partition mechanisms in the pulmonary system determined higher retention of the THM compounds with lower Henry's Law volatility constants than those of higher constant values. Inhalation is therefore the primary mechanisms for THM exposure of swimmers in indoor buildings.

Exposure assessment and the risk associated with trihalomethanes compounds in drinking water

Resumen en: Objective: To measure the concentrations of trihalomethanes (THMs) in marshland of Jacarepagua drinking water, Rio de Janeiro-RJ, Brazil, and their assoc...

A comparison of the role of two blue–green algae in THM and HAA formation

The contribution of two blue–green algae species, Anabaena flos-aquae and Microcystis aeruginosa, to the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) was investigated. The experiments examined the formation potential of these disinfection by-products (DBPs) from both algae cells and extracellular organic matter (EOM) during four algal growth phases. Algal cells and EOM of Anabaena and Microcystis exhibited a high potential for DBP formation. Yields of total THMs (TTHM) and total HAAs (THAA) were closely related to the growth phase. Reactivity of EOM from Anabaena was slightly higher than corresponding cells, while the opposite result was found for Microcystis. Specific DBP yields (yield/unit C) of Anabaena were in the range of 2–11 μmol/mmol C for TTHM and 2–17 μmol/mmol C for THAA, while those of Microcystis were slightly higher. With regard to the distributions of individual THM and HAA compounds, differences were observed between the algae species and also between cells and EOM. The presence of bromide shifted the dominant compounds from HAAs to THMs.

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.

The comparative study of trihalomethanes in drinking water

The purpose of this study was to assess exposure of four trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane and bromoform) in drinking water of Okinawa Island and Samoa. Trihalomethanes compounds were determined in the drinking water samples that were collected from the selected consumption sites and treatment plants of both Okinawa and Samoa in 2003–2004. The Chatan and Nishihara Water Treatment Plants (Okinawa) uses both ozonation and chlorination for primary and secondary disinfection. For Samoa Water Treatment Plants only chlorination is used as primary disinfection. Results showed that the mean concentration of trihalomethanes from treatment plants in Okinawa ranged from 0.30 ± 1.81 ⧎g/L to 11 ± 2.68 ⧎g/L and from the consumption sites ranged from 2.08 ± 0.32⧎g/L to 19.39 ± 100 ⧎g/L. In comparison, the mean concentration of trihalomethanes from the treatment plants in Samoa ranged from 226 ± 81.2 ⧎g/L to 267 ± 92.3 ⧎g/L and from the consumption sites were in the ranges 212 ± 101 ⧎g/L to 387 ± 125 ⧎g/L. Brominated compounds were commonly seen in all samples collected in Okinawa. Among the trihalomethanes compounds, chloroform was the common detected trihalomethanes in the samples collected from Samoa. The trihalomethanes levels in all samples collected in Okinawa and Samoa were generally below the guideline values in Japan, but some samples displayed levels which exceeded the level of Japan Water Quality and WHO Standards for chlorinated and brominated compounds.

Removal of trihalomethanes from drinking water by nanofiltration membranes

Chlorine reacts with the natural organic matter (NOM) in waters and forms disinfection by-products (DBP). Major of these by-products are trihalomethanes (THM) and haloacetic acids (HAA). They have been known to cause cancer and other toxic effects to human beings. This study determined the removal efficiencies of THM by nanofiltration (NF) techniques with NF200 and DS5 membrane. The rejection of this chlorination by-products was studied at various feed concentration by changing transmembrane pressure. Experimental results indicated that in general increasing operating pressure produces a higher flux but does not have a significant effect on THM rejection. On the other hand, increasing the feed concentration produces a little change in the overall flux and rejection capacity. NF200 membrane removed more THM than DS5 membrane. The higher removal efficiency of dibromochloromethane (DBCM) was attributed to brominating characteristics (higher molecular weight (MW) and molecular size). As a consequence, the results of this study suggest that the NF membrane process is one of the best available technologies for removing THM compounds.

Occurrence of disinfection by-products in low DOC surface waters in Turkey

A total of 29 surface waters from different regions of Turkey were sampled once a month during 2004. Filtered raw water samples were characterized, chlorinated and the concentrations of disinfection by-products (DBPs) were measured. All waters were low in DOC ranging from 0.91 to 4.42 mg/L. The range of annual average trihalomethanes (THMs) and haloacetic acids (HAAs) concentrations in all waters was 21–189 and 18–149 μg/L, respectively. Total mass contributions of halides in THMs and HAAs to absorbable organic halides (AOX) ranged between 10 and 56% in all waters on annual average basis, indicating that significant amounts of other DBPs are being formed in the majority of the tested waters. A strong linear correlation was obtained between the concentrations of THMs and HAAs. Rather poor correlations were found for THMs–AOX and HAAs–AOX levels. For both THMs and HAAs, chlorinated species dominated over brominated ones since the majority of water sources had very low bromide levels. While chloroform and trichloroacetic acid were the major THM and HAA compounds, respectively; the extent of formation and speciation of DBPs varied greatly by season and water source. No consistent general trends were observed in terms of seasonal variations in DBP levels, suggesting that the characteristics of NOM moieties and their chlorine reactivity vary by season in almost all waters tested.

Multi-pathway risk assessment of trihalomethanes exposure in Istanbul drinking water supplies

The lifetime cancer risk and the hazard index of trihalomethanes (THMs) through oral ingestion, dermal absorption, and inhalation exposure from tap water of 15 districts in Istanbul are estimated. The most dominant THM compounds are chloroform, bromodichloromethane (BDCM), and dibromochloromethane (DBCM) in Istanbul tap water. The results indicate that within three different pathways, Istanbul residents had a higher cancer risk through oral ingestion than through the other two pathways. The lifetime cancer risks of oral ingestion for total THMs was highest in Esenyurt district, while the lowest lifetime cancer risk for total THMs was in Basaksehir district. The lifetime cancer risks of chloroform, BDCM, and DBCM from tap water of all 15 districts were higher than 10−6, the negligible risk level defined by the USEPA. Among the 15 districts, people living in Esenyurt have the highest risk of cancer due to the THM exposure through the multi-pathways, mainly because of the exposure to BDCM and DBCM. The total cancer risk analysis concluded that each year approximately 5 of the 8 million Istanbul residents could get cancer from the daily intake of tap water.

Trihalomethanes aqueous solutions sono-oxidation

Ultrasonic (US) irradiation, hydrogen peroxide (H 2O 2), Fenton's oxidation and the combination of the processes were investigated for destruction and removal of the following trihalomethanes (THMs) compounds from aqueous solutions: CHCl 3, CHBrCl 2, CHBr 2Cl, CHBr 3, and CHI 3. H 2O 2 had no significant effect on the THMs sonodegradation. The coupled US and Fenton processes did not affect the CHCl 3, CHBrCl 2, and CHBr 2Cl sonolysis efficiency. Nevertheless, the sonodegradation of CHBr 3 was enhanced. CHI 3 was degraded by Fenton's oxidation rather than by the US irradiation during the sonication/Fenton treatment. The combination of sonication with H 2O 2 or Fenton's reagent did not affect the mineralization of the THMs aqueous mixture.

Trihalomethane Determination and Removals from the Main Discharge Channel of Konya City (Turkey)

Konya Main Discharge Channel is a very important environmental problem due to carrying the domestic waste water of Konya city centre as well as industrial waste water. Lowest flow rate of the channel was observed in October about 2 104 m3 d-1. In this period, channel water is not only waste water but includes more rain water coming from Gölyazı region. Discharge channel water can only reach to Tuz Lake for three months in a year. At other times of the year, water cannot reach the lake because of high evaporation, infiltration and usage of the water for irrigation. The land irrigated with the waste water tends to lose its productivity. In this study, water samples were collected and analysed from one hourly period for 2 days (24×2=48), daily period for 3 weeks (7×3=21) and monthly samples for a year (9 months). The samples were analysed as to whether these contained trihalomethanes or not, also results were compared with disinfection method that is used for drinking water, and samples were collected from ten different points on the channel. Pollution level of the channel water was controlled in accordance with the Turkish Water Pollution Control Law. In addition to trihalomethanes analysis, the effect of aeration on trihalomethanes was investigated. Collected samples (given above) were analysed for trihalomethanes compounds, and the relationship between disinfection type and dosage method on trihalomethanes formation was compared in this study.

Trihalomethanes in public water supplies and risk of stillbirth.

The chlorine used to disinfect public drinking water supplies reacts with naturally occurring organic matter to form a number of chemical byproducts. Recent studies have implicated exposure to chlorination byproducts in drinking water, trihalomethanes (THMs), in particular, with intrauterine death. We conducted a population-based case-control study in Nova Scotia and Eastern Ontario, Canada, to examine the effect of exposure to THMs on stillbirth risk. Cases were women who had a stillborn infant, and controls were a random sample of women with live births. Subjects were interviewed, and women with a public water source provided a residential water sample. Risks were examined according to residential THM level in tap water and to a total exposure metric incorporating tap water ingestion, showering, and bathing. We enrolled 112 stillbirth cases and 398 live birth controls. Women with a residential total THM level of 80 or more microg/L had twice the risk of a stillbirth compared with women with no exposure to THMs (adjusted odds ratio [OR] = 2.2; 95% confidence interval [CI] = 1.1-4.4). The highest quintile of total THM exposure using the total exposure metric was associated with an adjusted odds ratio of 2.4 (95% CI = 1.2-4.6) compared with women not exposed to THMs. Similar results were seen for specific THM compounds. A monotonic dose-response relationship was not seen. Our results provide evidence for an increased risk of stillbirth associated with exposure to chlorination byproducts through ingestion and showering and bathing, although there was not a clear dose-response relationship.

Bromine Distribution Factors in THM Formation

Trihalomethanes (THMs), a group of drinking water disinfection by‐products, are suspected carcinogens and are currently regulated by the U.S. Environmental Protection Agency. More stringent regulation of individual and total THM species is anticipated to meet the requirements of the 1986 Safe Drinking Water Act amendments. Because of this new focus on individual compounds, a set of statistical relationships called the bromine distribution factors were developed to characterize the impact of bromide ion on the distribution of THM formation potential (THMFP) species. A new derivation of these relationships is presented in this paper. Careful data analysis in combination with sound reasoning leads to a set of simultaneous equations that, when solved analytically, result in model coefficients that give both statistically sound and physically meaningful predictions for the distribution of THM compounds. Two independent data sets, including simulated distribution‐system THM data as well as THMFP data, were used...

Trihalomethanes (THMs) formation in multi-stage flash (MSF) distillation plants

The presence of trihalomethanes in distillate produced by multi-stage flash (MSF) distillation plant is monitored. The study covers the four THMs compounds; namely, chloroform (CHCl 3), bromodichloromethane (CHCl 2Br), dibromochloromethane (CHClBr 2) and bromoform (CHBr 3). The concentrations of THMs compounds in process streams like chlorinated seawater, make-up, recirculating brine and blow-down in addition to distillate are determined. These levels are correlated with parameters such as streams temperature, pH and residual chlorine. The effects of the presence of organic matter in seawater and the addition of organic chemicals necessary to ensure effiicent running of the plant are investigated. Furthermore, the impact of the distillation plant flashing regime on the overall formation and distribution of THMs is also studied. Mathematical formulations are derived which enable the prediction of THMs concentration in the distillate by measuring the THMs concentration in seawater make-up feed.