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.     

Occurrence of disinfection by-products in tap water distribution systems and their associated health risk

The concentrations of trihalomethanes (THMs), including chloroform, bromodichloromethane, dibromochloromethane, and bromoform, and haloacetic acids (HAAs; monochloroacetic acid, monobromoacetic acid, dibromoacetic acid, dichloroacetic acid, and trichloroacetic acid) were measured in tap waters passing through water distribution systems of six water treatment plants in Seoul, Korea, and their associated health risks from exposure to THMs through ingestion, dermal contact, and inhalation were estimated using a probabilistic approach. The concentration ranges for total THMs and HAA₅ were 3.9–53.5 and <LOD–49.5 μg/L, respectively. Among DBPs, chloroform, bromodichloromethane, dichloroacetic acid, and trichloroacetic acid were the most frequently detected. Spatial and seasonal variations in concentrations of THMs and HAAs in the six water distribution systems were significant (P?<?0.001).The mean lifetime cancer risks through ingestion, dermal contact, and inhalation during showering ranged as 7.23–10.06?×?10^?6, 2.19–3.63?×?10^?6, and 5.22–7.35?×?10^?5, respectively. The major exposure route to THMs was inhalation during showering. Sensitivity analysis showed that shower time and shower frequency had a great impact on the lifetime cancer risk by the exposure to THMs in tap water.     

垃圾填埋场地下水污染对居民健康的风险评价

调查了某垃圾填埋场地下水和周边居民饮用水中的As、Hg等重金属和挥发酚等有机物的污染状况，运用美国环保局的健康风险计算模型，评估了该垃圾填埋场地下水对周边居民的潜在健康风险。结果表明，各类人群对4种有阈化合物的饮食和皮肤暴露的终身健康危险度在8．2×10^-11～1．3×10^-10之间，均低于可以接受的风险水平10^-6；对As的终身超额健康危险度在3．1×10^-7～4．9×10^-7之间，表明地下水中砷污染对居民潜在的致癌风险不明显。各类人群通过皮肤对Hg、As、Cd和挥发酚的暴露剂量比通过饮水暴露的剂量高0．7倍～14．5倍，皮肤暴露将是地下水影响人体健康并构成潜在风险的重要途径。     

Assessment of health risk associated with persistent organic pollutants in water

This paper presents the results of analyses of water samples taken from water intakes supplying one of the districts located near the city of Wroc?aw. Surprisingly high concentrations of polychlorinated biphenyls and chloroorganic pesticides, classified as persistent organic pollutants (POPs), were detected in the monitored sites. Basing on the analytical and toxicological data, the individual health risks related to carcinogenic effects (excess cancer risk over a lifetime) in humans were assessed, resulting from direct ingestion of community water. Also noncarcinogenic effects resulting from exposure to the examined POPs were determined. The conservative approach to risk assessment, taking into account a safety margin for data incompleteness, was adopted. The carcinogenic risk was found to slightly exceed the unconditionally acceptable risk of 10^?6 in the case of polychlorinated biphenyls and hexachlorocyclohexane, for all the inhabitant populations. The determined values of noncarcinogenic effects expressed by hazard quotient and hazard index indicate that the water pollutants and their concentrations do not cause an increase in noncarcinogenic incidences in the inhabitants using the monitored water sources.     

Polycyclic aromatic hydrocarbons in water, sediment and soil of the Songhua River Basin, China

The Songhua River is the third largest river in China and the primary source of drinking and irrigation water for northeastern China. The distribution of 16 priority polycyclic aromatic hydrocarbons (PAHs) in water [dissolved water (DW) and suspended particulate matter (SPM)], sediment, and soil in the river basin was investigated, and the associated risk of cancer from these PAHs was also assessed. The total concentration of PAHs ranged from 13.9 to 161 ng L^?1 in DW, 9.21 to 83.1 ng L^?1 in SPM, 20.5 to 632 ng g^?1 dw (dry weight) in sediment, and from 30.1 to 870 ng g^?1 dw in soil. The compositional pattern of PAHs indicated that three-ring PAHs were predominant in DW and SPM samples, while four-ring PAHs dominated in sediment and soil samples. The spatial distribution of PAHs revealed some site-specific sources along the river, with principal component analysis indicating that these were from pyrogenic sources (such as coal and biomass combustion, and vehicle emissions) and coke oven emission distinguished as the main source of PAHs in the Songhua River Basin. Based on the ingestion of PAH-contaminated drinking water from the Songhua River, cancer risk was quantitatively estimated by combining the Incremental Lifetime Cancer Risk assessment model and BaP-equivalent concentration for five age groups of people (adults, teenagers, children, toddlers, and infants). Overall, the results suggest that the estimated integrated lifetime cancer risk for all groups was in acceptable levels. This study is the first attempt to provide information on the cancer risk of PAHs in drinking water from the Songhua River.     

Potability of water sources in relation to metal and bacterial contamination in some northern and north-eastern districts of India

A total of 1094 water samples from 326 springs, 207 streams, 183 dug wells, 151 piped supplies, 90 tube wells, 75 hand pumps, 60 rivers and 2 lakes were collected from eight northern and six north-eastern districts of India. Samples were analysed to assess their potability by estimating the level of heavy metals and bacterial (coliform and faecal coliform) contaminations. Iron was found in a maximum number (53%) of water samples from hand pumps, followed by lead in 43% of the tube wells, chromium in 16% of dug wells, cadmium in 13% of streams and manganese in 7% of hand pumps above their maximum admissible concentrations (MACs). Maximum metal pollution has been observed in a considerable number of water samples from Doda, followed by Almora, Mirzapur and Bankura. Hand pump water samples exhibited maximum metal pollution followed by dug well, spring, stream and river water samples. Contamination of coliform and/or faecal coliform bacteria ranged between 41% and 67% of water samples from open water sources but it was also less, i.e. 6–15% of water samples from tube wells and hand pumps. In general, 42–85% of water samples from districts surveyed, except from Jammu (18%) and Mirzapur (27%), were found to be bacteriologically unsatisfactory. Since toxic metals and pathogenic bacteria pose a risk to public health, monitoring of drinking water sources is required.     

Drinking water quality assessment in Southern Sindh (Pakistan)

The southern Sindh province of Pakistan adjoins the Arabian Sea coast where drinking water quality is deteriorating due to dumping of industrial and urban waste and use of agrochemicals and yet has limited fresh water resources. The study assessed the drinking water quality of canal, shallow pumps, dug wells, and water supply schemes from the administrative districts of Thatta, Badin, and Thar by measuring physical, chemical, and biological (total coliform) quality parameters. All four water bodies (dug wells, shallow pumps canal water, and water supply schemes) exceeded WHO MPL for turbidity (24%, 28%, 96%, 69%), coliform (96%, 77%, 92%, 81%), and electrical conductivity (100%, 99%, 44%, 63%), respectively. However, the turbidity was lower in underground water, i.e., 24% and 28% in dug wells and shallow pumps as compared to open water, i.e., 96% and 69% in canal and water supply schemes, respectively. In dug wells and shallow pumps, limits for TDS, alkalinity, hardness, and sodium exceeded, respectively, by 63% and 33%; 59% and 70%, 40% and 27%, and 78% and 26%. Sodium was major problem in dug wells and shallow pumps of district Thar and considerable percent in shallow pumps of Badin. Iron was major problem in all water bodies of district Badin ranging from 50% to 69% and to some extent in open waters of Thatta. Other parameters as pH, copper, manganese, zinc, and phosphorus were within standard permissible limits of World Health Organization. Some common diseases found in the study area were gastroenteritis, diarrhea and vomiting, kidney, and skin problems.     

Determination of volatile organic compounds pollution sources in malaysian drinking water using multivariate analysis

A field investigation was conducted at all water treatment plants throughout 11 states and Federal Territory in Peninsular Malaysia. The sampling points in this study include treatment plant operation, service reservoir outlet and auxiliary outlet point at the water pipelines. Analysis was performed by solid phase micro-extraction technique with a 100 μm polydimethylsiloxane fibre using gas chromatography with mass spectrometry detection to analyse 54 volatile organic compounds (VOCs) of different chemical families in drinking water. The concentration of VOCs ranged from undetectable to 230.2 μg/l. Among all of the VOCs species, chloroform has the highest concentration and was detected in all drinking water samples. Average concentrations of total trihalomethanes (THMs) were almost similar among all states which were in the range of 28.4--33.0 μg/l. Apart from THMs, other abundant compounds detected were cis and trans-1,2-dichloroethylene, trichloroethylene, 1,2-dibromoethane, benzene, toluene, ethylbenzene, chlorobenzene, 1,4-dichlorobenzene and 1,2-dichloro - benzene. Principal component analysis (PCA) with the aid of varimax rotation, and parallel factor analysis (PARAFAC) method were used to statistically verify the correlation between VOCs and the source of pollution. The multivariate analysis pointed out that the maintenance of auxiliary pipelines in the distribution systems is vital as it can become significant point source pollution to Malaysian drinking water.     

Organochlorine pesticide residues in drinking water in the rural areas of Haryana,India

Drinking water samples collected from rural areas of three districts of Haryana during pre-monsoon and post-monsoon periods were analysed for the presence of organochlorine pesticide residues. The main source of drinking water in rural areas, i.e. groundwater in Ambala and Gurgaon districts and surface water supply in Hisar district, was found to be contaminated with isomers of HCH and endosulfan and metabolites of DDT, whereas dieldrin remained below detection limits. During the study period, the mean values observed for total HCH, DDT and endosulfan were 87.6, 848.2, and 27.4 ng/L and 99.8, 275.3 and 164.2 ng/L, respectively, for Ambala and Gurgaon districts. In the case of Hisar district, the values were 78.5, 115.9, and 53.0 ng/L, respectively. During the study period, 37% of the samples exceeded the total pesticide level of 500 ng/L indicated in the EECD directive for drinking water. Seasonal variations of pesticide residues were also observed during the study period.     

Investigations on boron levels in drinking water sources in China

To evaluate boron contamination of public drinking water in China, both dissolved and total boron contents in 98 public drinking water sources from 49 cities, 42 brands of bottled water samples from supermarkets in several cities, and 58 water samples from boron industrial area were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Our experimental results showed that boron existed in public drinking water sources mainly in dissolved status with total concentrations ranging from 0.003 to 0.337 mg/L (mean = 0.046 mg/L). The mean boron concentrations in mineral and pure bottled water were 0.052 and 0.028 mg/L, respectively. The results obtained in this work showed that there was no health risk on view of boron in public drinking water sources and bottled water. In boron industrial area, boron concentrations in surface water and ground water were 1.28 mg/L (range = 0.007–3.8 mg/L) and 18.3 mg/L (range = 0.015–140 mg/L), respectively, which indicated that boron industry caused boron pollution in local water system.     

Risk assessment of soils contaminated by mercury mining, Northern Spain

Analytical results of soil samples taken in three different mercury mining sites in Northern Spain are studied to assess the potential adverse health effects of the exposure to trace elements associated with the mining process. Doses contacted through ingestion and inhalation and the dose absorbed through the skin were calculated using USEPA's exposure parameters and the US Department of Energy's toxicity values. The results of the risk assessment indicate that the highest risk is associated with ingestion of soil particles and that the trace element of major concern is arsenic, the exposure to which results in a high cancer risk value for all the sites ranging from 3.3 × 10(-5) to 3.6 × 10(-3), well above the 1 × 10(-5) probability level deemed unacceptable by most regulatory agencies. Regarding non-cancer effects, exposure to polluted soils yields an aggregate hazard index above the threshold value of 1 for all three sites, with As and Hg as the main contributors. Risk assessment has proven to be a very useful tool to identify the contaminants and exposure pathways of most concern in the soils from metal mining sites, as well as to categorize them in terms of action priority to ensure fitness for use.     

Trihalomethane formation potential in treated water supplies in urban metro city

Trihalomethane (THM) formation potential (TFP) is very useful test to assess the level of the formation of trihalomethanes in worst case scenario. Organics in water have the potential to generate harmful disinfection by-products (DBPs) such as THMs, as a result of their reaction with disinfectant chlorine used in drinking water. DBPs are increasingly recognized as cancerous agents. TFP of postchlorinated treated water were investigated at six water treatment plants (WTPs) in Delhi City (India). The present paper presents the current trends of TFP so that prevention and control measures can be initiated by the regulating agencies responsible for drinking water supply. Liquid–liquid extraction method, followed by qualitative and quantitative estimation by gas chromatograph equipped with electron capture detector, had been used for the determination of THMs in water samples collected at the outlet just before supplying to the consumers during 2000–2007. The TFP values from 2004 onward of all WTPs did not exceed the WHO guideline value of ≤1.     

青岛市饮用水源地重金属污染物健康风险初步评价

对青岛市某饮用水源地饮用水的钼、铍、硼、锑、钡、钒、钛、铊、砷、镉、铅、汞、镍、铜、锌共15种重金属元素进行了分析,并应用美国环保局推荐的健康风险评价模型对其所引起的健康风险作了初步评价。结果表明,通过饮水途径所致健康风险中,由致癌物砷所致的健康风险为8.15E-6 a-1,低于国际辐射防护委员会ICRP推荐的最大可接受风险水平5.0×10-5a-1;由非致癌物所致的健康风险中砷最大,铜和硼次之,二者的风险水平为10-9a-1和10-10a-1,均低于ICRP推荐的最大可接受风险水平。     

Monitoring bacterial contamination of piped water supply in rural coastal Bangladesh

Safe drinking water is scarce in southwest coastal Bangladesh because of unavailability of fresh water. Given the high salinity of both groundwater and surface water in this area, harvested rainwater and rain-fed pond water became the main sources of drinking water. Both the government and non-government organizations have recently introduced pipe water supply in the rural coastal areas to ensure safe drinking water. We assessed the bacteriological quality of water at different points along the piped water distribution system (i.e., the source, treatment plant, household taps, street hydrants, and household storage containers) of Mongla municipality under Mongla Upazila in Bagerhat district. Water samples were collected at 2-month interval from May 2014 to March 2015. Median E. coli and total coliform counts at source, treatment plant, household taps, street hydrants, and household storage containers were respectively 225, 4, 7, 7, and 15 cfu/100 ml and 42,000, 545, 5000, 6150, and 18,800 cfu/100 ml. Concentrations of both of the indicator bacteria reduced after treatment, although it did not satisfy the WHO drinking water standards. However, re-contamination in distribution systems and household storage containers indicate improper maintenance of distribution system and lack of personal hygiene.     

Polycyclic aromatic hydrocarbons in urban soils of Hangzhou: status,distribution, sources,and potential risk

Concentration, composition profile, spatial distribution, sources, and health risk of 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed in 69 surface soil samples collected from Hangzhou urban districts. ∑PAHs ranged from 180.77 to 1,981.45 μg kg^?1 with a mean of 611.28 μg kg^?1. Among different functional areas, a higher level of PAHs was found in the roadsides, followed by commercial districts, residential areas, parks, and greenbelts. The composition of PAHs was characterized by high molecular weight PAHs (4?~?6 rings). Principal component analysis (PCA) and PAH isomeric ratios indicated that PAHs mainly originated from combustion, especially vehicle exhaust. The incremental lifetime cancer risks (ILCRs) associated with exposures to PAHs in soil were calculated separately for children and adults under normal and extreme conditions. The results showed that ILCRs for urban soil of Hangzhou were acceptable. However, attentions should be attracted on the sites of high PAH concentrations because the ILCRs were closed to 10^?4 under extreme conditions, especially for children.     

Groundwater contamination by polycyclic aromatic hydrocarbon due to diesel spill from a telecom base station in a Nigerian City: assessment of human health risk exposure

Diesel pollution of groundwater poses great threat to public health, mainly as a result of the constituent polycyclic aromatic hydrocarbons (PAHs). In this study, the human health risk exposure to polycyclic aromatic hydrocarbons (PAHs) in diesel contaminated groundwater used by several families at Ring Road, Jos, Nigeria (as caused by diesel spill from a telecom base station) was assessed. Prior to the groundwater being treated, the residents were using the water after scooping off the visible diesel sheen for purposes of cooking, washing, and bathing. Until this study, it is not clear whether the groundwater contamination had resulted in sub-chronic exposure of the residents using the water to polycyclic aromatic hydrocarbons (PAHs) to the extent of the PAHs posing a health risk. The diesel contaminated groundwater and uncontaminated nearby groundwater (control) were collected and analyzed for PAHs using gas chromatography-mass spectrometry (GC-MS). The dosage of the dermal and oral ingestion entry routes of PAHs was determined. The estimation of the non-carcinogenic health risk was via hazard quotients (HQ) and the associated hazard index (HI), while the estimation of the carcinogenic health risk was via lifetime cancer risks (LCR) and the associated risk index (RI). Obtained results indicate that the exposure of the residents to the PAHs may have made them susceptible to the risk of non-carcinogenic health effects of benzo(a)pyrene and the carcinogenic health effects of benzo(a)anthracene and benzo(a)pyrene.     

长江口南通地区饮用水源地健康风险评价

对长江口南通地区饮用水源地中镉、砷、六价铬等有毒有害物质的浓度进行了调查,并应用目前美国环保局推荐的健康风险评价模型对各饮用水源地有毒有害物质所引起的健康风险做了初步评价。结果表明,长江口南通地区饮用水源地通过饮水途径基因毒物质中化学致癌物所产生的健康风险的数量级为10^-8~10^-5,其中As 在如海河和新通扬运河所引起的致癌风险最大,高于国际辐射防护委员会(ICRP) 推荐的通过饮水途径最大可接受风险水平;通过饮水途径引起的非致癌健康风险远低于ICRP 推荐的最大可接受风险水平。基因毒物质中砷和六价铬这2种毒物应被列为该地区饮用水源地水和水厂制水过程中优先检测和控制的致癌污染物,应重点关注基因毒物质六价铬和砷对人体所产生的健康风险。     

The role of GC-MS and LC-MS in the discovery of drinking water disinfection by-products

Gas chromatography-mass spectrometry (GC-MS) has played a pivotal role in the discovery of disinfection by-products (DBPs) in drinking water. DBPs are formed when disinfectants, such as chlorine, ozone, chlorine dioxide or chloramine, react with natural organic matter in the water. The first DBP known--chloroform--was identified by Rook in 1974 using GC-MS. Soon thereafter, chloroform and other trihalomethanes were found to be ubiquitous in chlorinated drinking water. In 1976, the National Cancer Institute published results linking chloroform to cancer in laboratory animals, and an important public health issue was born. Mass spectrometry and, specifically, GC-MS became the key tool used for measuring these DBPs in water and for discovering other DBPs that were formed. Over the last 25 years, hundreds of DBPs have been identified, mostly through the use of GC-MS, which has spawned additional health effects studies and regulations. Early on, GC with low resolution electron ionization (EI)-MS was used, together with confirmation with chemical standards, for identification work. Later, researchers utilized chemical ionization (CI)-MS to provide molecular weight information and high resolution El-MS to aid in the determination of empirical formulae for the molecular ions and fragments. More recently, liquid chromatography-mass spectrometry (LC-MS) with either electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) has been used to try to uncover highly polar DBPs that most experts believe have been missed by earlier GC-MS studies. Despite 25 years of research in the identification of new DBPs, new ones are being discovered every year, even for chlorine which has been the most extensively studied.     

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).     

Geo-spatial analysis of land–water resource degradation in two economically contrasting agricultural regions adjoining national capital territory (Delhi)

The present study was aimed at characterizing the soil-water resource degradation in the rural areas of Gurgaon and Mewat districts, the two economically contrasting areas in policy zones-II and III of the National Capital Region (NCR), and assessing the impact of the study area's local conditions on the type and extent of resource degradation. This involved generation of detailed spatial information on the land use, cropping pattern, farming practices, soils and surface/ground waters of Gurgaon and Mewat districts through actual resource surveys, standard laboratory methods and GIS/remote sensing techniques. The study showed that in contrast to just 2.54% (in rabi season) to 4.87% (in kharif season) of agricultural lands in Gurgaon district, about 11.77% (in rabi season) to 24.23% (in kharif season) of agricultural lands in Mewat district were irrigated with saline to marginally saline canal water. Further, about 10.69% of agricultural lands in the Gurgaon district and 42.15% of agricultural lands in the Mewat district were drain water irrigated. A large part of this surface water irrigated area, particularly in Nuh (48.7%), Nagina (33.5%), and Punhana (24.1%) blocks of Mewat district, was either waterlogged (7.4% area with 0.05 ppm). In fact, sub-surface drinking waters of some areas around battery and automobile manufacturing units in Gurgaon and Pataudi blocks were associated with exceptionally high (>0.1 ppm) Ni concentrations. In general, the ground waters of waterlogged or potentially waterlogged areas in the rural areas of Mewat were more contaminated than the ground waters in the rural areas of Gurgaon district with deeper (>5 m) water depths.Though Cr concentrations in the surface and sub-surface irrigation waters of both Gurgaon and Mewat districts were far above the maximum permissible limit of 1 ppm, their bio-available soil-Cr concentrations were well within permissible limit. Even bio-available Ni concentrations in agricultural lands of Gurgaon district associated with Ni contaminated sub-surface irrigations were well within desirable limit of 0.20 ppm. This was primarily attributed to the calcareous nature of the soils of the study area. About 35% of Gurgaon district and 59% of Mewat district irrigated with poor quality waters were salt-affected. These waterlogged/potentially waterlogged calcareous-salt affected soils of Mewat district were having acute zinc (Zn) deficiency (<0.6 ppm). Some areas with extremely high iron (Fe: 20-25 ppm) and Mn (10-25 ppm) concentrations were also noticed in the Gurgaon, Nuh and Punhana blocks. Generation of reduced conditions owing to paddy cultivation in areas with 3-3.5 m water depths appeared to be the main cause of such point contaminations. Extensive cadmium (Cd) contamination was also noticed in the waterlogged sodic agricultural lands of Nagina village in Mewat district associated with a large scale scrap automobile and battery business. The study could document the processes and provide spatially accurate information to the managers (e.g., National Capital Region Planning Board) and the concerned citizen groups. It could, in fact, clearly point out that dumping of industrial and domestic wastewaters especially from NCT-Delhi into river Yamuna and, to some extent, from NCT-Delhi re-located hazardous industrial units into Najafgarh drain tributaries at Delhi-Gurgaon boundary, and poor "off-farm" water management practices were the main reasons for extensive (point/non-point source) land-water degradation in Gurgaon and Mewat districts of NCR.