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Compounds originating from animal husbandry can pollute surface water through the application of manure to soil. Typically, grab sampling is employed to detect these residues, which only provides information on the concentration at the time of sampling. To better understand the emission patterns of these compounds, we utilized passive samplers in surface water to collect data at eight locations in a Dutch agricultural region, during different time intervals. As a passive sampler, we chose the integrative-based Speedisk® hydrophilic DVB. In total, we targeted 46 compounds, among which 25 antibiotics, three hormones, nine antiparasitics, and nine disinfectants. From these 46 compounds, 22 compounds accumulated in passive samplers in amounts above the limit of quantification in at least one sampling location. Over the 12-week deployment period, a time integrative uptake pattern was identified in 53% of the examined cases, with the remaining 47% not displaying this behavior. The occurrences without this behavior were primarily associated with specific location, particularly the most upstream location, or specific compounds. Our findings suggest that the proposed use of passive samplers, when compared in this limited context to traditional grab sampling, may provide enhanced efficiency and potentially enable the detection of a wider array of compounds. In fact, a number of compounds originating from animal husbandry activities were quantified for the first time in Dutch surface waters, such as flubendazole, florfenicol, and tilmicosine. The set-up of the sampling campaign also allowed to distinguish between different pollution levels during sampling intervals on the same location. This aspect gains particular significance when considering the utilization of different compounds on various occasions, hence, it has the potential to strengthen ongoing monitoring and mitigation efforts., (© 2024. The Author(s).)

The reactions between natural organic matter, anthropogenic contaminants, ions, and disinfectants lead to the formation of disinfection by-products (DBPs) such as trihalomethanes (THMs) in drinking water. The formation of THMs is strongly related to the chlorination of water. The study's central objective was to compare the concentration of THMs in twenty developed and developing countries and their disinfection techniques. The THM concentration in 11 developed and 9 developing countries ranged from 0.5 µg/L (Germany) to 215 µg/L (Russia) and 3 µg/L (China) to 439.2 µg/L (Bangladesh), respectively. The developed country has partially succeeded in reducing THM concentration in drinking water, whereas significant steps are needed in developing countries to reduce the existing high THM concentration. The concentration of THMs in water varies among these countries because of the different water sources, water quality, environmental conditions, and efficiency of water treatment technologies. A meaningful relationship has been observed between the properties of water and the THM formation. The use of chemical disinfectants will result in new forms of DBPs that are undesirable due to their carcinogenic and mutagenic effects on human health. The DBP guidelines by various national and international agencies have helped to control and manage the THM concentration in drinking water. However, these regulatory standards are not continuously monitored. Therefore, the formation of these compounds should be prevented either by removing THMs forming precursors or by using an integrated approach for controlling THM formation by implementing advanced water treatment technology. Extensive research is desirable in domains like THM minimization strategies which are easy to deploy, scalable, and cost-effective., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

In this review, we depict the state of the art concerning the water quality management of bio-mineral bathing pools, and compare these to traditional swimming pools. Bio-mineral pools use a combination of mechanic filtration, bio-filtration, and UV-treatment to disinfect the water. Studies in test tanks have shown that bio-filtration is effective in maintaining the water quality with regard to the treatment of organic pollution. Concerning biological risks, the bio-mineral pool relies on UV-treatment to degrade bacteria. Unlike chemical disinfectant treatments, UV disinfection does not lose its effectiveness in the event of high traffic in the pool. However, as only the water taken up by the filtration system is disinfected, it is essential that all the water in the pool is filtered. If the pool has a dead zone, its water is not disinfected and there is a risk of localized pathogen development. As the development of bio-mineral pools spreads in Europe, legislation gradually follows. The health parameters measured differ slightly from one country to another, but there are constants: the measurement of Escherichia coli, Enterococci, and Pseudomonas aeruginosa. In terms of biological swimming pools, regulatory homogeneity across Europe does not exist. From these comparisons, Austrian legislation segmenting water quality into 4 categories ranging from "excellent" to "poor" represents legislation that combines health and safety with indications of possible malfunctions. Next, a study of three real sites of bio-mineral pools is presented. It appears that whatever the type of pool, bio-mineral filtration makes it possible to achieve performances comparable to those encountered in chlorinated swimming pools concerning the risks associated with fecal contamination and external pollution. On the other hand, when frequentation is high, as is the case in small pools used for aquafitness, monitoring the risks of inter-bather contamination, as illustrated by the presence of Staphylococcus aureus, reveals a recurring problem. Knowing that this parameter is not evaluated in bathing waters in the natural environment and that numerous studies show that Staphyloccocus aureus are always detected, even on beaches, we propose the definition of three thresholds: i.e., 0 CFU/100 mL (threshold value in Wallonia) for water of excellent quality, less than 20 CFU/100 mL (threshold value in France) for water of very good quality, less than 50 CFU/100 mL (contribution of bathers by simple immersion) for good quality water, and more than 50 CFU/100 mL for poor quality water. This document could therefore be converted into a manual for operators on the use and management of bio-mineral baths., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The present work shows the evaluation of the decay of free residual chlorine in several public swimming pools in the city of Medellín, observing that a decrease in residual chlorine does occur. Some factors accelerate the decrease in the concentration of free residual chlorine in recreational water, such as the number of bathers in the pool, the pH, and the temperature of the water. For this reason, the concentration of the disinfectant rapidly decreases to an extent that the health of swimmers could be put at risk. The Authority of Health of Medellín carries out inspection, surveillance and quality control activities of water for recreational use. These purposes of these include guaranteeing the reduction of risk factors to the health of the users of said pools.

Applying a desirable disinfestation process is necessary to control the pathogenic microorganisms in the swimming pools and prevent both dermal and intestinal effects. Therefore, the present study was conducted to compare the bacterial community and diversity in the two swimming pools disinfected by the chlorine and ozone (O 3 )-chlorine processes. A total of 24 samples were taken from the two swimming pools in three distinct seasons to analyze the bacterial and physico-chemical indicators. Culture and molecular methods were used to evaluate the microbial quality. Two sets of sample taken from the pools with the maximum swimmer load in the summer were investigated by the next-generation sequencing (NGS) technique. In total, 410 and 406 bacterial species were identified in the chlorine- and ozone-chlorine-disinfected pools, respectively. Among the eight dominant bacterial species in each swimming pool, Pseudomonas alcaliphila, Pseudomonas stutzeri, and Pseudomonas acnes were common species between the two studied pools. Oleomonas sagaranensis (350 reads/18593), Staphylococcus caprae (302 reads /18593), and Anaerococcus octavius (110 reads/18593) were among the dominant bacteria in the chlorine-disinfected pool. Bacterial diversity was lower in the ozone-chlorine-disinfected pool than the other one, and the highest bacterial sequencing belonged to the genus Pseudomonas (85.79%). Results showed that water quality of in O 3 -chlorine-disinfected pool was more desirable than the chlorine-disinfected pool. Molecular methods along with conventional culture methods would be advantageous for microbial assessment in the swimming pools.

Disinfection is used to deactivate pathogens in drinking water. However, disinfectants react with natural organic matter present in water to form disinfection by-products (DBPs). While a few of these DBPs have been studied extensively and are regulated in many countries, new unregulated DBPs (UR-DBPs) have also recently been identified in drinking water. The UR-DBPs are considered to be more toxic than regulated DBPs (R-DBPs). To understand the occurrence of UR-DBPs in a water distribution network (WDN), this research presents an approach to predicting the behaviour of emerging UR-DBPs such as dichloroacetonitrile (DCAN), trichloropropanone (TCP), and trichloronitromethane (TCNM) in WDNs. Water quality data, generated by sampling and laboratory analysis of 12 small communities, was used to develop predictive models. A framework was also proposed alongside the predictive models to estimate the concentration of emerging UR-DBPs under limited water quality sampling information. Moreover, the relationship between emerging UR-DBP concentrations and their identified predictors was further observed and evaluated by developing contour profiles. DCAN and TCP predictive models have coefficient of determination (R 2 ) > 85%, whereas for TCNM model, the R 2 was > 65%. Water quality parameters including water temperature, turbidity, conductivity, and dissolved organic carbon concentrations were identified as key predictors. Similarly, trichloroacetic acid and bromodichloromethane were identified as key predictors among DBP families, to predict the occurrence of emerging UR-DBPs. Developed models and relationships between the UR-DBPs and predictors can help water utilities and regulators to manage the occurrence of UR-DBPs in small WDNs.

Quenching agents (QAs) are widely used in order to prevent the additional formation of disinfection by-products (DBPs) during the sample holding time. In addition, DBP levels are usually stabilized by adjusting the pH of water samples. Previous studies have mostly focused on the individual effects of QAs or of pH on the stability of DBPs in water samples. Considering that disinfectant quenching and pH adjustments are applied simultaneously during routine analyses, it is more appropriate to evaluate the stability of DBPs with all the chemicals (e.g., disinfectants, QAs, buffers) present in the water. This study investigated the synergistic effects of different QAs (ascorbic acid, ammonium chloride, or no quenching) and pH adjustment (3-9) strategies on the stability of different classes of DBPs (i.e., trihalomethanes (THMs), halogenated acetaldehydes (HALs), haloacetonitriles (HANs), haloketones (HKs), and halonitromethane (HNM)). Sample preservation conditions that did not include a QA were shown to be inadequate for GC-ECD analysis, due to interference problems. Ammonium chloride was found to be effective for most DBPs. However, some HALs continued to form in the presence of chloramine, which is a by-product of dechlorination using ammonium chloride. Conversely, using ascorbic acid efficiently inactivated residual chlorine, providing a clean chromatographic baseline. Based on the results of this study, we recommend the use of ascorbic acid for quenching and sulfuric acid for acidifying (pH 3.5) samples. Considering the instability of some DBPs in water matrices over long periods (i.e., 14 days), samples should be processed as soon as possible after collection.

Degradation of source water quality complicates water treatment processes, resulting in additional treatment cost and tap water quality deterioration. In this study, source water quality was investigated for 441 water supply systems (WSSs) during the period of 18 years (1999-2016). The investigation was performed on 21 water quality parameters (WQPs) for groundwater (GWS) and surface water (SWS) sources. The averages of dissolved organic carbon (DOC), color, and Kjeldahl nitrogen (N) were much higher in SWS than GWS while other 18 WQPs (e.g., alkalinity, conductivity, and pH) were higher in GWS. In SWS, averages of DOC during 2000-2005, 2006-2010, and 2011-2015 were 6.08, 6.74, and 6.78 mg/L, respectively. In these periods, pH were 6.39, 6.62, and 6.77, respectively. In GWS, averages of DOC in these periods were 1.43, 1.36, and 1.81 mg/L, respectively, while pH were 7.50, 7.69, and 7.89, respectively. The DOC in SWS and GWS were increasing at the rates of 0.0722 and 0.0491 mg/L/year, respectively, while pH were increasing at the rates of 0.0375 and 0.0441 units/year, respectively. Trihalomethanes showed increasing trends in drinking water from SWS and GWS while haloacetic acids showed no trend. In SWS, DOC and its rate of increase were higher while in GWS, pH and its rate of increase were higher. The higher DOC and pH, and their increasing rates could increase disinfection byproducts (DBPs) in drinking water. Many DBPs are known as possible or probable human carcinogens and some DBPs are regulated. The other WQP and their increasing patterns can also impart new challenges, which are likely to increase the treatment cost and/or deteriorate drinking water quality.

The small water supply systems (WSSs) often report high concentrations of disinfection by-products (DBPs) in drinking water. In this study, occurrences of trihalomethanes (THMs) and haloacetic acids (HAAs) in Newfoundland and Labrador (NL), Canada, were investigated from 441 WSSs for a period of 18 years (1999-2016). The WSSs were divided into groundwater (GWP) and surface water (SWP) systems, which were further classified into eight sub-groups (P1-P8) based on the population served (≤ 100; 101-250; 251-500; 501-1000; 1001-3000; 3001-5000; 5001-10,000; and 10,000+, respectively). The DBPs with probable and possible carcinogenic forms were estimated. Overall, 31.1% of WSSs were GWP, in which averages of THMs and HAAs were 32.2 and 27.7 μg/L, respectively, while the SWP had averages of THMs and HAAs of 97.6 and 129.2 μg/L, respectively. The very small WSSs (P1-P3) of GWP had averages of THMs and HAAs in the ranges of 29.1-43.5 and 15.8-64.3 μg/L, respectively. The P1-P3 of SWP had averages of THMs and HAAs in the ranges of 92.6-112.8 and 108.0-154.0 μg/L, respectively, which often exceeded the Canadian guideline limits. If the samples represented the populations homogenously, the total populations exposed to THMs or HAA 5 above the guideline values would be in the range of 132.08-181.38 in thousands (30.3-41.6% of total populations). The probable and possible carcinogenic forms of THMs in GWP and SWP were in the ranges of 4.8-48.8 and 4.4-7.0% of THMs, respectively. In HAAs, carcinogenic forms were in the ranges of 82.6-98.4 and 97.6-98.7%, respectively. The findings indicated that the SWP might need further attention to better protect human health.

Among all the organic disinfection by-products (DBPs), only trihalomethanes (THMs) and haloacetic acids (HAAs) are regulated in drinking water, while most DBPs are not. Very little information exists on the occurrence of non-regulated DBPs, particularly in small water systems (SWS). Paradoxically, SWS are more vulnerable to DBPs because of a low capacity to implement adequate treatment technologies to remove DBP precursors. Since DBP analyses are expensive, usually SWS have difficulties to implement a rigorous characterization of these contaminants. The purpose of this study was to estimate non-regulated DBP levels in SWS from easy measurements of relevant parameters regularly monitored. Since no information on non-regulated DBPs in SWS was available, a sampling program was carried out in 25 SWS in two provinces of Canada. Five DBP families were investigated: THMs, HAAs, haloacetonitriles (HANs), halonitromethanes (HNMs), and haloketones (HKs). Multivariate linear mixed regression models were developed to estimate HAN, HK, and HNM levels from water quality characteristics in the water treatment plant, concentrations of regulated DBPs, and residual disinfectant levels. The models obtained have a good explanatory capacity since R 2 varies from 0.77 to 0.91 according to compounds and conditions for application (season and type of treatment). Model validation with an independent database suggested their ability for generalization in similar SWS in North America.

In this study, the variations in concentrations of some disinfection chemicals such as cyanuric acid (CyA), free chlorine (FC), and residual chlorine (RC), which affect human health, were investigated in the water of swimming pools. In addition, quality parameters such as temperature, pH, and total alkalinity (TA) in 44 swimming pools located in the city center and districts of Canakkale, Turkey, were examined in the summer period. While FC and RC amounts were analyzed using tablet tests with N-N-diethyl phenylenediamine (DPD 1) and potassium iodine (DPD 3) using the colorimetric method in the comparator, TA and CyA levels were measured with a photometric method. Temperature and pH were measured using YSI 556 MPS. Levels of CyA, FC, RC, pH, temperature, and TA varied between 0.00 and 725.0 mg L -1 (108.0 ± 111.4 mg L -1 ), 0.00 and 5.00 mg L -1 (1.60 ± 0.962 mg L -1 ), 0 and 0.55 mg L -1 (0.087 ± 0.059), 6.40 and 8.20 mg L -1 (7.30 ± 0.038 mg L -1 ), 22.0 and 32.0 °C (27.6 ± 1.45 °C), and 0.00 and 391.0 mg L -1 (129.3 ± 89.0), respectively. The findings were compared to standard limit values of the Ministry of Health of the Turkish Republic and other countries. Not only maximum concentrations of CyA but also the average concentrations exceeded the standard limit values of different countries in July and August with high tourism activity in Turkey. Although there is no problem in view of average values of other quality parameters, there are some problems in view of the maximum values in pool waters compared to standard limit values.

In this work, we evaluated the risk posed to aquatic organisms in the coastal waters of Albania and Apulia (Italy) by two priority pollutants (PPs), Irgarol 1051 and Diuron, used as biocides in antifouling paints on boat hulls. With this aim, we carried out an extensive 3-year monitoring in ports and marinas along the coasts of both countries, which showed a widespread occurrence of both PPs, with Irgarol 1051 concentrations usually being lower than the Diuron ones. The measured concentrations were compared with regulatory Environmental Quality Standards (EQS) (Directive 2008/105/EC) and used to perform a probabilistic Ecological Risk Assessment (ERA), for a thorough evaluation of the potential adverse effects upon marine ecosystem. Irgarol 1051 amounts above the Annual Average Concentration (AA-EQS, 2.5 ng/L) were often detected in Apulia and, less frequently, in Albania. Moreover, in Apulia, sometimes the Maximum Allowable Concentrations (MAC-EQS, 16 ng/L) was exceeded. In Apulia, where levels exceeded MAC/AA-EQS, ERA found not negligible probabilities of exceeding the toxicity level (6-18 %). A less critical situation was observed for Diuron whose levels were always below the MAC-EQS (1800 ng/L) in both countries and, in Albania, also below the AA-EQS (200 ng/L). On the other hand, in Apulia, this limit was exceeded in some locations. Correspondingly, ERA determined a not negligible risk in these sites (probability of exceedance 4-7 %).

Inactivating pathogens is essential to eradicate waterborne diseases. However, disinfection forms undesirable disinfection by-products (DBPs) in the presence of natural organic matter. Many regulations and guidelines exist to limit DBP exposure for eliminating possible health impacts such as bladder cancer, reproductive effects, and child development effects. In this paper, an index named non-compliance potential (NCP) index is proposed to evaluate regulatory violations by DBPs. The index can serve to evaluate water quality in distribution networks using the Bayesian Belief Network (BBN). BBN is a graphical model to represent contributing variables and their probabilistic relationships. Total trihalomethanes (TTHM), haloacetic acids (HAA5), and free residual chlorine (FRC) are selected as the variables to predict the NCP index. A methodology has been proposed to implement the index using either monitored data, empirical model results (e.g., multiple linear regression), and disinfectant kinetics through EPANET simulations. The index's usefulness is demonstrated through two case studies on municipal distribution systems using both full-scale monitoring and modeled data. The proposed approach can be implemented for data-sparse conditions, making it especially useful for smaller municipal drinking water systems.

The hygienic quality of drinking water for cattle originated from different sources together with the efficacy and usability of two types of disinfectants against waterborne pathogens were assessed for small cattle breeders and dairy cattle farms. A total of 120 drinking water samples were collected from water troughs representing three different water sources commonly used for cattle drinking (tap, underground and surface water; n = 65, 25, and 30, respectively). Collected samples were cultured for isolation and identification of pathogenic bacteria using serological techniques and PCR. The bactericidal efficacy of the disinfectants, sodium dichloroisocyanurate (NaDCC) and hydrogen peroxide (H2O2) 50%, at different concentrations were evaluated by the determination of total viable and coliform counts of water prior and postwater treatment. In small cattle breeders, Escherichia coli was the most prevalent bacterial isolates from surface water (56.7%) followed by Staphylococcus aureus (36.7%), Salmonella spp. (26.7%), Streptococcus faecalis (23.3%), Shigella flexneri (16.7%), Proteus spp. (16.7%), and Klebsiella pneumonae (10.0 %) at X(2) = 9, P ≤ 0.01. Prior to the use of disinfectants, the averages of total bacterial and coliform counts were the highest in surface water (3.56 × 10(7), 240.0, and 38.0 CFU/100 ml, respectively). It has been found that hydrogen peroxide 50% at a concentration of 35 mg/l had a lethal effect (100 %) on indicator microorganisms compared with NaDCC at concentration of 2 mg/l. In conclusion, the higher bacterial contaminants in drinking water were found in surface water followed by tap water, particularly for small cattle breeders. Therefore, the usage of more hygienic water troughs with their regular treatment by hydrogen peroxide 50% at concentration of 35 mg/l is highly recommended to control waterborne bacteria and consequently improve and maintain the animal health.

Potable water samples (N = 74) from 19 zip code locations in a region of Greece were profiled for 13 trace elements composition using inductively coupled plasma mass spectrometry. The primary objective was to monitor the drinking water quality, while the primary focus was to find novel associations in trace elements occurrence that may further shed light on common links in their occurrence and fate in the pipe scales and corrosion products observed in urban drinking water distribution systems. Except for arsenic at two locations and in six samples, rest of the analyzed elements was below maximum contaminant levels, for which regulatory values are available. Further, we attempted to hierarchically cluster trace elements based on their covariances resulting in two groups; one with arsenic, antimony, zinc, cadmium, and copper and the second with the rest of the elements. The grouping trends were partially explained by elements' similar chemical activities in water, underscoring their potential for co-accumulation and co-mobilization phenomena from pipe scales into finished water. Profiling patterns of trace elements in finished water could be indicative of their load on pipe scales and corrosion products, with a corresponding risk of episodic contaminant release. Speculation was made on the role of disinfectants and disinfection byproducts in mobilizing chemically similar trace elements of human health interest from pipe scales to tap water. It is warranted that further studies may eventually prove useful to water regulators from incorporating the acquired knowledge in the drinking water safety plans.

The objective of this study was to predict chloroform formation resulting from the process of disinfecting water, particularly trihalomethane which is most frequently produced. A statistical model was used which included repeated measurements of water parameters used for monitoring water quality at 51 sites covering the municipal water system of Montevideo. Samples were taken considering different seasons from June 2009 to July 2011 in Montevideo. Total samples (n = 330) were analytically studied using the headspace-gas chromatography method coupled with mass spectrometry. Chloroform was the dependent variable and the covariables were pH, temperature, free chlorine, and total chlorine. A Tobit analysis with an unstructured correlation matrix was performed, and a significant interaction was found between pH and free chlorine for the prediction of chloroform formation. We concluded that parameters for the continuous control of water quality for consumption can be used to predict the levels of chloroform that may be present. Given the large measurement to variability found in the repeated measurements, the use of averages that include more than one season is not recommended to determine the degree of compliance with acceptable levels established by norms.

The spatiotemporal presence of eight N-nitrosamines in the water of seven supply systems in Quebec considered to be susceptible to these emerging disinfection by-products was evaluated. This is the first study on the presence of N-nitrosamines in drinking water utilities in Quebec. Seven sampling campaigns were carried out at several sampling points in each of the systems over a period of 1 year. The results show that N-nitrosamines, primarily N-nitrosodimethylamine (NDMA), were not commonly detected in the water of the facilities under study (10 % of samples). The concentrations measured were lower than those reported in recent North American studies. None of the 195 samples taken exceeded the Ontario standard of 9 ng/L for NDMA (maximum value observed of 3.3 ng/L). N-nitrosomethylethylamine and N-nitrosopiperidine were detected once, with concentrations of 3.7 and 6.0 ng/L, respectively. Chloramination was identified as being the main risk factor regarding the presence of N-nitrosamines, but water quality and some operating parameters, in particular disinfectant residual, also seem to be related to their presence. NDMA concentrations at the end of the distribution systems were generally higher than water leaving the plant. No seasonal trends were observed for the formation of N-nitrosamines in the investigated supply systems. Finally, an association between the presence of N-nitrosamines and the levels of trihalomethanes and haloacetic acids was observed in some facilities.

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

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.

In spite of the importance and popularity of swimming pools in summer, they have been identified as posing some public health risks to users due to either chemical or microbiological contamination. This study was carried out aiming at assessing the quality of water for some Alexandria's swimming pools in order to determine its compliance with the Egyptian standards no. 418/1995. Five swimming pools were selected randomly from different districts. Physical and chemical parameters, as well as biological examination of a total of 30 samples, were carried out using standard analytical methods. Water samples were collected from the studied swimming pools monthly over 6 months and pool water monitoring was carried out during afternoon of the weekends when the pools were most heavily used. The results indicated overall poor compliance with the standards. Compliance of the pool water to the microbial parameters, residual chlorine, pH, and turbidity were 56.7% (17 samples), 20% (6 samples), 46.7% (14 samples), and 46.7% (14 samples), respectively. Statistical analysis showed significant association between water contamination with microbial indicators and physical-chemical aspects such as residual chlorine, temperature, turbidity, and load of swimmers. Furthermore, Cryptosporidium oocysts and Giardia lamblia cysts has been found in 10% of samples. It was concluded that there is a need to improve disinfection and cleaning procedures, with consideration given to safety, and size of the pool in relation to bathing load. There is also a need to monitor swimming pool water quality continuously, and to increase bather hygienic practices and awareness of the risks as well as training of governmental inspectors.

This study assesses the prevalence of disinfection by-product (DBP) precursors in some Southeast Queensland drinking water sources by conducting formation potential experiments for the four regulated trihalomethanes (THMs), and the potent carcinogen, N-nitrosodimethylamine (NDMA). NDMA formation potentials were consistently low (<5-21 ng/L), and total THM (tTHM) formation potentials were consistently below the Australian Drinking Water Guideline (250 μg/L). NDMA concentration of finished drinking waters was also monitored and found to be <5 ng/L in all cases. The effect of coagulation and advanced oxidation on the formation of NDMA and THMs is also reported. UV/H(2)O(2) pre-treatment was effective in producing water with very low THMs concentrations, and UV irradiation was an effective method for NDMA degradation. H(2)O(2) was not required for the observed NDMA degradation to occur. Coagulation using alum, ferric chloride or poly(diallyldimethylammonium chloride) (polyDADMAC) was ineffective in removing DBPs precursors from the source water studied, irrespective of the low dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) attained. Rather, coagulation with polyDADMAC caused an increase in NDMA formation potential upon chloramination, and all coagulants led to an increased tTHM formation potential upon chlorination due to the high bromide concentration of the source water studied.

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.

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 (HAA(5)) in finished drinking water were evaluated. The major species of HAA(5) 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.

This investigation conducted a full-scale survey the drinking water distribution system in Kaohsiung city, Taiwan. The aim was to investigate whether the distribution system was capable of maintaining high water quality from the water treatment facilities through to the end user. The results showed that the distribution system can maintain high water quality, except for suitable chlorine residuals. The authors plotted chlorine residual contour maps to identify areas with low chlorine residuals, helping them prioritize sections that must be flushed or renewal. The contour maps also provide sufficient and clear information for locating booster chlorination stations. Contour maps enable water facilities to identify how water quality decays in the distribution systems and the locations of such decay. Water quality decay can be caused by properties of pipeline materials, hydraulic conditions, and/or biofilm thickness. However, understanding the exact reasons is unnecessary because the contour maps provide sufficient information for trouble-shooting the distribution systems.

A funded research project was conducted during the period July 1992 through November 1994. The project was designed to evaluate indoor and ambient air quality in and around buildings of different types and uses in Riyadh, the capital of Saudi Arabia. Thirty intercity buildings and two outercity (background) sites were carefully selected and monitored for air quality. Ten air pollutants, together with relevant meteorological parameters, were monitored indoor and outdoor at each site continuously and simultaneously for a period of two weeks covering summer and winter seasons. This article discusses the results obtained for sulfur dioxide (SO2), ammonia (NH3) and formaldehyde (HCHO). Results of this investigation revealed that most sites had on the average exceeded the recommended standards for SO2 and NH3 both indoor and outdoor, with indoor levels being worse than outdoor during winter time. Several sites also showed high levels of HCHO, with outdoor levels being consistently higher than indoor. Statistical and frequency analyses were performed on the collected data, showing seasonal and sector by sector variability, and outdoor-indoor correlations.

In the United States, the newly promulgated disinfectant/disinfection by-product (D/DBP) regulations force water treatment utilities to be more concerned with finished and distributed water qualities. In this study, monitoring of DBP formation was conducted from three French water treatment plants trying to assess DBP variations through time and space. Compared to the in-plant total trihalomethanes (TTHM) levels, TTHM levels in the distribution system increased from less than 150% to more than 300%. Significant variations for TTHM and bromate (BrO3-) levels throughout the seasons were also observed; generally higher levels in the summer and lower levels in the winter. Combining chemical DBP models (empirical power functional models) and hydraulic simulations, DBPs including TTHM and BrO3- were successfully simulated from the full-scale monitoring data, indicating that empirical DBP model can be a potential tool to access DBP formation in actual plants. This study also provides the protocols to assess DBP simulations in the water treatment systems.

Toxicity monitoring of field water samples was performed using a novel multi-channel two-stage mini-bioreactor system and genetically engineered bioluminescent bacteria for the continuous monitoring and classification of the toxicity present in the samples. The toxicity of various samples spiked with known endocrine disrupting chemicals and phenol was also investigated for system characterization. The field samples used in this study were obtained from two different sites on a monthly basis--from a drinking water treatment plant, referred to as site N, and from a stream near a dam which is currently being constructed, referred to as site T. These samples were either pumped or injected into the second mini-bioreactors to initiate the toxicity test. Most of the samples did not show any specific toxicity. However, one sample showed to have, based upon the detection results, and was deemed toxic. The samples spiked with phenol showed possible responses in the DPD2540 and TV1061 channels, indicating the occurrence of both membrane and protein damage due to phenol. In the tests using an endocrine disrupting chemical, bisphenol A, DNA damage was detected in the DPD2794 channel with a concentration of 2 ppm. Finally, a simple but novel early warning protocol that can be used in a drinking water reservoir and a suspected place where effluents of toxic materials enter the water sourse was suggested with a schematic diagram. In conclusion, this system showed good feasibility for use as a toxicity monitoring system in the field and as an early warning system, indicating if effluents are toxic.