Cancer risk assessment from exposure to trihalomethanes in tap water and swimming pool water

We investigated the concentration of trihalomethanes （THMs） in tap water and swimming pool water in the area of the Nakhon Path- om Municipality during the period April 2005-March 2006. The concentrations of total THMs, chloroform, bromodichloromethane, dibromochloromethane and bromoform in tap water were 12.70-41.74, 6.72-29.19, 1.12-11.75, 0.63-3.55 and 0.08-3.40 μg/L, respectively, whereas those in swimming pool water were 26.15-65.09, 9.50-36.97, 8.90-18.01, 5.19-22.78 and ND-6.56 μg/L, respectively. It implied that the concentration of THMs in swimming pool water was higher than those in tap water, particularly, brominated-THMs. Both tap water and swimming pool water contained concentrations of total THMs below the standards of the World Health Organization （WHO）, European Union （EU） and the United States Environmental Protection Agency （USEPA） phase Ⅰ, but 1 out of 60 tap water samples and 60 out of 72 swimming pool water samples contained those over the Standard of the USEPA phase Ⅱ. From the two cases of cancer risk assessment including Case Ⅰ Non-Swimmer and Case Ⅱ Swimmer, assessment of cancer risk of nonswimmers from exposure to THMs at the highest and the average concentrations was 4.43×10^-5 and 2.19×10^-5, respectively, which can be classified as acceptable risk according to the Standard of USEPA. Assessment of cancer risk of swimmers from exposure to THMs at the highest and the average concentrations was 1.47×10^-3 and 7.99×10^-4, respectively, which can be classified as unacceptable risk and needs to be improved. Risk of THMs exposure from swimming was 93.9%-94.2% of the total risk. Cancer risk of THMs concluded from various routes in descending order was： skin exposure while swimming, gastro-intestinal exposure from tap water intake, and skin exposure to tap water and gastro-intestinal exposure while swimming. Cancer risk from skin exposure while swimming was 94.18% of the total cancer risk.

Research on Relationship Between Fluorine in Tap Water and That in Urine of Chinese Residents

In this study, the relationship between fluorine in drinking water and that in urine of urban residents in China is assessed. Fluorine concentrations in tap water and those in urine show a good correlation with a linear regression coefficient of 0.9798, indicating that the fluorine concentrations in big cities under investigation are extremely low, and the main source of fluorine is tap water. The weather effect on the intake amount of fluorine is also discussed. When air temperature is above 15℃, people would intake more fluorine through drinking water with the rise of air temperature. When temperature is below 15℃, no remarkable relationship is observed between air temperature and the intake amount of fluorine. This phenomenon indicates that the main source of fluorine in China is tap water instead of foodstuff.

Effect of Pipe Diameter on Electrochemical Behavior of Stainless Steel Type 304 Pipes in Tap Water

We investigated the effects of pipe diameter on the corrosion resistance of stainless steel type 304 pipes using electrochemical measurements. Compared to plate steel, pipes have harder physical properties and tend to be harder and showed greater permeability with decreasing inner diameter. We found that the maximum corrosion current density in the secondary active state, which is the starting point of secondary passivation, appeared in the polarization curve measurement in tap water. Similar to the Vickers hardness and the maximum current density in the secondary active state, the permeability tended to increase as the diameter decreased. This is thought to increase the amount of deformation-induced martensitic and increase corrosion susceptibility. The peak of the secondary active current density was clearly seen as the potential sweep speed was increased. In addition, potential sweep speed dependence was observed in the corrosion susceptibility evaluation of deformation-induced martensite. In comparison with acid treatment, the formation of deformation-induced martensite was considered to occur in the extreme surface layer. The maximum corrosion current density in the secondary active state is expected to be a new susceptibility evaluation method for evaluating the deformation-induced martensitic transformation.

Preparation and Application of an Low-Aluminium Tap Water Flocculant

A kind of environmental friendly novel composite flocculants which are used to treat raw water is prepared. It is made with chitosan (CS), iron modified polyaluminium chloride (CF-PAC) and modified montmorillonite on the principle of “the combination of organic and inorganic”. Under the optimum best compound formula and flocculation process, the turbidity of the waste water reduced by 0.62%, the chemical cost decreased by 12.43% and the content of aluminium ions dropped by 70.65%. There is an excellent characteristic and higher efficiency on the composite flocculant which can adsorb the organic matter in the water and chelate the heavy metal ions in the water.

Corrosion in Tap Water and Hot Water Supply Facilities of Stainless Steel Type 304 Pipes

We performed corrosion case study and corrosion tests to assess the corrosion resistance of stainless steel type 304 pipes in tap water and hot water facilities. Circulating test equipment used for corrosion tests and two types of sample, plates and straight pipe specimens, were examined under different conditions of residual chlorine concentration in the test water. The results of case study analysis indicated that high degrees of pitting corrosion occurred on straight pipes with inner diameter < 50 mm. The results of corrosion tests showed that the residual chlorine concentration around the pitting corrosion of stainless steel type 304 was greater than 0.3 mg/L in the plate, regardless of the remaining chlorine concentration in the straight pipe specimens. These results suggest that straight pipes have higher corrosion susceptibility because of bending during production.

Tap Water versus Bottled Water: A Pilot Study

The aim of this exploratory research and comparative numerical pilot study was to investigate any significant differences in the microbiological content of tap and bottled water through the measurement of risk indicator parameters including Enterococci, Escherichia coli (E. coli) and colony-forming units (CFUs). This study to investigate storage conditions and compare consumer options of public water supply and bottled water using microbiological limits was carried out for public health research. This was a unique pilot study to Northern Ireland with global relevance due to the increase in the bottled water market and the need to address the lack of consumer awareness regarding storage and microbiological content. No E. coli or Enterococci were found in any of the 31 tap or bottled water samples. Three unrefrigerated bottled water samples exceeded the threshold in Colony Counts 22°C & 37°C (degrees Celsius) and failed in line with Drinking Water Directive guidelines. This indicated a link between storage conditions and microbiological quality. No link between prices or microbiological quality was indicated. This research recommends the creation of a regulator for the bottled water industry, the need for clearly labelled microbiological content and daily testing. Water suppliers such as Northern Ireland (NI) Water should promote the quality of tap water. Recommendations are also outlined for consumers. There is no statistically significant difference in the microbiological quality of tap and bottled water in Northern Ireland despite marketing claims.

Occurrence of viable but non-culturable(VBNC)pathogenic bacteria in tap water of public places

Viable but non-culturable(VBNC)bacteria have been detected in source water and effluent of drinking water treatment processes,leading to significant underestimation of viable cell counts.Limited information exists on VBNC bacteria in tap water,particularly in public places.To address this gap,a comprehensive nine-month study was conducted in a major city in south-eastern China,using culture-based and quantitative PCR with propidium monoazide(PMA)dye methods.Forty-five samples were collected from five representative public places(railway station,campus,hospital,shopping mall,and institution).The findings revealed that culturable bacteria represented only 0–17.51%of the viable 16S rRNA genes,suggesting that the majority of viable bacteria existed in an uncultured or VBNC state.Notably,opportunistic pathogens such as Escherichia coli,Enterococcus faecalis,Pseudomonas aeruginosa,Salmonella sp.,and Shigella sp.were primarily detected as VBNC cells,with concentrations ranging from 1.03×10^(0)to 3.01×10^(3),1.20×10^(0)to 1.42×10^(2),1.32×10^(0)to 8.82×10^(0),1.00×10^(0)to 6.71×10^(1),and 2.07×10^(0)to 1.93×10^(2)cell equivalent/100 mL,respectively.Culturable P.aeruginosa was observed in tap water after prolonged stagnation,indicating potential risks associated with bacterial regrowth.Spatial and temporal factors accounted for 17.1%and 26.0%,respectively,of the variation in tap water community structure during the sampling period,as revealed by 16S rRNA amplicon sequencing.This study provides quantitative insights into the occurrence of VBNC bacteria in tap water and highlights the need for more sensitive monitoring methods and microbial control techniques to enhance tap water safety in public locations.

Basin-scale exposure risk of psychiatric pharmaceuticals and illicit drugs in tap water in Eastern China

A total of twenty-three psychiatric pharmaceuticals and illicit drugs were analyzed in tap water covering seven basins in Eastern China.The residual concentrations of these substances were detected up to 22.4 ng L^(-1).Among the substances,benzodiazepines were more often detected with higher median concentrations than those of illicit drugs.Generally,the higher residual levels of psychoactive substances were detected in the upstream of the basins compared with the downstream.For example,the concentrations of diazepam,temazepam,and oxazepam in the downstream were much higher than those in the upstream in OJ.Among the basins,YH was the most polluted region.Exposure assessment indicated the median exposure doses of diazepam and temazepam were from 85 to 99 and 3.5e4.1 pg kg^(-1) bw d^(-1) in the basins,respectively.Benchmark quotient for the nine detected substances was calculated in each basin with the range from 0.0001 to 0.0389,indicating low risk in the tap water for human health under current concentrations.

Tap water microbiome shifts in secondary water supply for high-rise buildings

In high-rise buildings,secondary water supply systems(SWSSs)are pivotal yet provide a conducive milieu for microbial proliferation due to intermittent flow,low disinfectant residual,and high specific pipe-surface area,raising concerns about tap water quality deterioration.Despite their ubiquity,a comprehensive understanding of bacterial community dynamics within SWSSs remains elusive.Here we show how intrinsic SWSS variables critically shape the tap water microbiome at distal ends.In an office setting,distinct from residential complexes,the diversity in piping materials instigates a noticeable bacterial community shift,exemplified by a transition from a-Proteobacteria to g-Proteobacteria dominance,alongside an upsurge in bacterial diversity and microbial propagation potential.Extended water retention within SWSSs invariably escalates microbial regrowth propensities and modulates bacterial consortia,yet secondary disinfection emerges as a robust strategy for preserving water quality integrity.Additionally,the regularity of water usage modulates proximal flow dynamics,thereby influencing tap water's microbial landscape.Insights garnered from this investigation lay the groundwork for devising effective interventions aimed at safeguarding microbiological standards at the consumer's endpoint.

Antibacterial Performance of a Cu-bearing Stainless Steel against Microorganisms in Tap Water

Tap water is one of the most commonly used water resources in our daily life. However, the increasing water contamination and the health risk caused by pathogenic bacteria, such as Staphylococcus aureus and Escherichia coli have attracted more attention. The mutualism of different pathogenic bacteria may diminish antibacterial effect of antibacterial agents. It was found that materials used for making pipe and tap played one of the most important roles in promoting bacterial growth. This paper is to report the performance of an innovative type 304 Cu-bearing stainless steel(304Cu SS) against microbes in tap water. The investigation methodologies involved were means of heterotrophic plate count, contact angle measurements, scanning electron microscopy for observing the cell and subtract surface morphology,atomic absorption spectrometry for copper ions release study, and confocal laser scanning microscopy used for examining live/dead bacteria on normal 304 stainless steel and 304 Cu SS. It was found that the surface free energy varied after being immersed in tap water with polar component and Cu ions release.The results showed 304 Cu SS could effectively kill most of the planktonic bacteria(max 95.9% antibacterial rate), and consequently inhibit bacterial biofilms formation on the surface, contributing to the reduction of pathogenic risk to the surrounding environments.

Perfluorocarboxylic acids(PFCAs)and perfluoroalkyl sulfonates(PFASs)in surface and tap water around Lake Taihu in China

Perfluorinated compounds(PFCs)are ubiquitously distributed in the environment mainly as perfluorocarboxylic acids(PFCAs)and perfluoroalkyl sulfonates(PFASs).In this paper,six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East China.Predominant PFCs were perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),of which the concentration ranges were 6.8–206 and 1.2–45 ng·L^(–1),the geometric means were 35.3 and 9.4 ng·L^(–1),and the median(quartile range)values were 31.4(34.4)and 10.4(10.7)ng·L^(–1),respectively.Other PFCs were also detected but in much lower concentrations than PFOA.The sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area,and this area was also a possible source of PFCs contaminations in Shanghai district in the downstream.PFCs distributions were found different in the upstream,downstream and north part of Lake Taihu.Occurrences of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people.A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health,but chronic risks from PFOA in the tap water should be considered in the downstream regions.

Trihalomethane concentrations in tap water as determinant of bottled water use in the city of Barcelona

Bottled water consumption is increasing worldwide, despite its huge economic and environmental cost. We aim to describe personal and tap water quality determinants of bottled water use in the city of Barcelona. This cross-sectional study used data from the Health Survey of Barcelona in 2006（N = 5417 adults）. The use of bottled water to drink and to cook was evaluated in relation to age, gender, educational level, district and levels of trihalomethanes（THMs）, free chlorine, conductivity, chloride, sodium, p H, nitrate and aluminium in municipal tap water using Robust Poisson Regression. The prevalence of bottled water use to drink and cook was 53.9% and 6.7%, respectively. Chemical parameters in water had a large variability（interquartile range of THMs concentrations： 83.2–200.8 μg/L）and were correlated between them, except aluminium. Drinking bottled water increased with educational level, while cooking with bottled water was higher among men than among women and decreased with age. After adjusting by these personal determinants, a dose–response relationship was found between concentrations of all chemicals except aluminium in tap water and bottled water use. The highest association was found for THMs,with a Prevalence Ratio of 2.00（95%CI = 1.86, 2.15） for drinking bottled water and 2.80（95%CI = 1.72, 4.58） for cooking with bottled water, among those with 〉 150 μg/L vs. 〈 100 μg/L THMs in tap water. Conclusion： More than half of Barcelona residents regularly drank bottled water, and the main determinant was the chemical composition of tap water,particularly THM level.

Public Effective Dose Assessment Using Gross Alpha and Beta Radioactivity Levels of Tap Drinking Water in the District of Abidjan, Cote d’Ivoire

In order to assess public effective dose due to gross alpha and beta in water, 43 tap water samples were collected from different areas in the District of Abidjan. Using the low background Gas-less Automatic Alpha/Beta counting system (Canberra iMaticTM) for analysis, the gross alpha and beta concentrations found varied from 0.001 ± 0.002 to 0.063 ± 0.050 Bq/l with an average of 0.013 ± 0.012 Bq/l and from 0.067 ± 0.080 to 0.320 ± 0.120 Bq/l with an average of 0.174 ± 0.076 Bq/l, respectively in samples. The public effective dose assessment showed values of dose to ingestion of alpha and beta emitter radionuclides lower than the recommended value of dose for drinking water 0.1 mSv/y, except in 30% of the samples. These results show the need for additional studies to be conducted in order to clarify the hazardousness of these water samples. However, this study still remains important because it has provided necessary data for future tap water quality monitoring studies in the District of Abidjan.

News about Tap and Bottled Water: Can This Influence People’s Choices?

The pursuit of alternative safe water has increased dramatically the world trade in bottled water. Events happened in Canada which changed the population’s perception about the quality of tap water, despite all government efforts. Media has an important role to pass on information because there is value judgment in its reports. As a result, this study aims to present recent data from two Canadian newspapers of national circulation, which refer to tap water and bottled water. It used quantitative and qualitative data for this analysis. The study concludes that the media, taken into consideration, provides its readers with important information, but the information can also be ambiguous. Nevertheless, it arouses interest in further research about this subject matter and about protecting water resources.

Evaluation of nitrate and trace elements concentration in drinking water:Bottled,tap and well

Concentrations of nitrate and trace elements such as arsenic,cadmium,chromium,copper,manganese,nickel,lead,selenium,antimony and mercury in 18 different brands of bottled water were investigated.For comparison,samples of tap and well water from three different places of Tehran were also analyzed.UV/VIS spectrophotometer and Graphite Furnace Atomic Absorption Spectrometer were used for the analysis of nitrate and trace elements,respectively.Results obtained were compared to Iranian,World Health Organization(WHO)and Environmental Protection Agency(EPA)guideline for drinking water.Nitrate concentration in bottled,tap and well water samples were in maximum safe nitrate concentration of Iranian and WHO standards.However,70%of bottled water samples and one sample of tap water were below the standard level proposed by EPA and probably remedial action should be taken.Concentration levels of all analyzed elements investigated in all examined water samples were below the maximum contaminant level prescribed by Iranian,WHO and EPA regulations.

重力流供水设计优化研究及应用

以四川省通江县的方田坝水厂建设项目自来水全重力流供水为案例,根据现场实际情况,通过优化设计有效解决了高位、低位供水及用水高峰、低谷时间段供水流量调节的难题,在确保城区居民生活生产用水需求的同时达到节能供水的目的,为山区城镇自来水全重力流供水提供了先进可行的解决方案。

基于PLC的厂站设备及自动化改造

为实现自来水厂站设备自动化运行,提升厂站设备管理运行的可靠性及安全性,对某市投入运营的30000 t/d自来水厂站全厂工艺设备及自动化现状进行调研分析;对取水泵站、送水泵站、加药设备、中控设备、加压泵站、流量计等设备进行改造;改造后通过PLC控制及智能采集终端模块将关键设备参数及在线监测数据接入组态软件及智慧水务平台,实现远程控制功能,更加全面实时监控全厂及泵站设备运行状态。实现厂站自动化、智能化、智慧化的运营与管理,降低了运营成本。

巴江魂,渝水情——重庆自来水工业历史文化价值探究

作为工业遗产大类中的自来水工业遗产,是一切与城市用水的产业相关的工业遗存,同时也是水文化遗产的重要构成部分,其类型丰富,分布广泛。在重庆自来水工业发生、发展的辉煌历程中,重庆水务工作者铸就了甘作基石、勇担当的巴江魂,彰显了全力为民、乐奉献的渝水情。如今,一些重要的自来水工业遗产正日渐从山城民众的视野里消逝,因而开展重庆自来水工业文化遗产的发掘、保护及研究工作已迫在眉睫。

基于铬天青检测法对自来水中铝含量的优化检测研究

目的:提高铬天青检测法测定自来水中铝含量的效率和准确性。方法:在原方法基础上,对所有玻璃仪器进行硝酸预处理,排除铜、锰、铁和铝等金属离子的干扰;调整pH值后多加2滴硝酸并充分混合;显色过程中所需的4种试剂均需临用前配制,沿比色管内壁一次性定容后再摇匀。结果:优化方案在标准曲线0~0.250 mg/L范围内线性提升显著,相关系数r=0.9985~0.9997,标准点回算结果理想,环境标准样品测定结果准确。结论:优化方案简化了操作步骤,减少了系统误差,使结果更为准确。

Metagenomic perspectives on antibiotic resistance genes in tap water:The environmental characteristic,potential mobility and health threat

As an emerging environmental contaminant,antibiotic resistance genes(ARGs)in tap water have attracted great attention.Although studies have provided ARG profiles in tap water,research on their abundance levels,composition characteristics,and potential threat is still insufficient.Here,9 household tap water samples were collected from the Guangdong-Hong Kong-Macao Greater Bay Area(GBA)in China.Additionally,75 sets of environmental sample data(9 types)were downloaded from the public database.Metagenomics was then performed to explore the differences in the abundance and composition of ARGs.221 ARG subtypes consisting of 17 types were detected in tap water.Although the ARG abundance in tap water was not significantly different from that found in drinking water plants and reservoirs,their composition varied.In tap water samples,the three most abundant classes of resistance genes were multidrug,fosfomycin and MLS(macrolide-lincosamidestreptogramin)ARGs,and their corresponding subtypes ompR,fosX and macB were also the most abundant ARG subtypes.Regarding the potential mobility,vanS had the highest abundance on plasmids and viruses,but the absence of key genes rendered resistance to vancomycin ineffective.Generally,the majority of ARGs present in tap water were those that have not been assessed and are currently not listed as high-threat level ARG families based on the World Health Organization Guideline.Although the current potential threat to human health posed by ARGs in tap water is limited,with persistent transfer and accumulation,especially in pathogens,the potential danger to human health posed by ARGs should not be ignored.