Fluoride in drinking water exacerbates glomerulonephritis and induces liver damage in ICR-derived glomerulonephritis mice

To evaluate the effects of fluoride on the kidney and the liver of ICR-derived glomerulonephritis (ICGN) mice by using laboratory tests and pathological examinations, fluoride was administered to the ICGN mice at 0, 25, 50, 100, and 150?ppm in drinking water for 4 weeks and to the ICR mice, which have normal kidney function at 0 and 150?ppm. The BUN, creatinine, GOT, and GPT in the serum of each mouse were determined. When a mouse died, the sample from the day closest to the death was assigned for the mean. Pathological changes in the kidney were examined after PAS (periodic acid-Schiff) staining. All of the ICGN mice in the 150?ppm group and one of seven in the 100?ppm group died before the end of week 4, but no ICR mice died. For ICGN mice, the mean value of body weight in the 150?ppm group was significantly lower than those in 0?ppm group and other fluoride-administered groups. The mean values of relative liver and kidney weights in the 100 and 150?ppm groups were significantly lower than those in the control. The mean values of BUN, creatinine, and GPT in the 150?ppm group were significantly higher than those in the control. The thickness of the glomerular capillary wall and the increased mesangial matrix in the kidney were prominent in the fluoride-administered ICGN mice. These results suggested that fluoride severely exacerbated glomerulonephritis and tublar-intestitial changes in ICGN mice.     

Malaysian households' drinking water practices: A case study

Malaysia has abundant water resources and adequate rainfall and yet the nation has water shortages and water quality problem. Various measures have been taken by the government to address water issues but, in spite of these, quantity and quality of drinking water is still one of the main concerns of Malaysian consumers today. An exploratory study was undertaken to determine the level of awareness of respondents on water issues, assess their perception on drinking water quality, and identify measures undertaken by households to improve drinking water quality and to determine sustainable water practices. A cross-sectional research design, utilizing a survey was conducted among urban residents of Seremban town. Data showed that each household had a mean of five members, with an average household income of RM3788.00 (US$1000). The respondents were Chinese (70%), Indian (23%) and Malay (7%). The majority of respondents rated the quality of water supplied to their house as poor (70%), while 16% rated it very poor. The respondents indicated that colour, odour and taste were the main problems with their tap water. Due to the poor tap water quality perceived by respondents, most took additional measures to improve its quality. Most (85%) purchased domestic water filters, 41% boiled water and 17% bought bottled water. The reasons for purchasing water were: concern for health, perception of poor tap water quality, and increasing water contamination and pollution in the country. Almost a quarter of respondents that had water filters mentioned the convenience because they did not have to boil water. Sustainable use of water by respondents was moderate, with a mean of 2.9 on a scale of 1 (never) to 4 (all the time). Some aspects of conservation, such as the promptness of repairing leaking pipes, planning activities to conserve water, and method of car washing could be improved. Advantages and limitations of different water technologies are discussed. Sustainable water practices are also proposed.     

Disinfection byproducts in drinking water and regulatory compliance: A critical review

Disinfection by-products (DBPs) are regulated in drinking water in a number of countries. This critical review focuses on the issues associated with DBP regulatory compliance, including methods for DBP analysis, occurrence levels, the regulation comparison among various countries, DBP compliance strategies, and emerging DBPs. The regulation comparison between China and the United States (US) indicated that the DBP regulations in China are more stringent based on the number of regulated compounds and maximum levels. The comparison assessment using the Information Collection Rule (ICR) database indicated that the compliance rate of 500 large US water plants under the China regulations is much lower than that under the US regulations (e.g. 62.2% versus 89.6% for total trihalomethanes). Precursor removal and alternative disinfectants are common practices for DBP regulatory compliance. DBP removal after formation, including air stripping for trihalomethane removal and biodegradation for haloacetic acid removal, have gained more acceptance in DBP control. Formation of emerging DBPs, including iodinated DBPs and nitrogenous DBPs, is one of unintended consequences of precursor removal and alternative disinfection. At much lower levels than carbonaceous DBPs, however, emerging DBPs have posed higher health risks.     

Economists' opinions on environmental policy instruments: Analysis of a survey

Incentive instruments (effluent charges) are theoretically expected to be preferred to direct regulations (individual emission ceilings) by university-employed, theoretically inclined politically right-wing, professional economists living in a market-oriented country, ceteris paribus. Public sector employed, politically left-wing, professional economists living in a country with a long tradition of government involvement prefer the regulatory approach, ceteris paribus. These theoretical hypotheses tend to be supported by a bivariate probit analysis based on a survey of more than 1400 economists in five countries.     

Health effects of arsenic in drinking water: Research needs

Research needed to resolve the uncertainties of cancer risk from ingestion of arsenic in drinking water is described. The recommendations fall into two categories reflecting the areas of greatest uncertainty regarding the assessment of arsenic risk: research on the mechanism of cancer, and research on the metabolism and detoxification of arsenic. The recommendations are discussed in light of risk assessment and risk management issues, stressing the need for scientists to interpret research findings for decision managers.This document has been reviewed in accordance with the US Environmental Protection Agency Policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendations for use.     

Radioactivity in drinking water: Expert opinion and policy choices

To examine the preferences of experts to selected economic and policy options in ground-water protection, we conducted an exploratory survey. We presented a group of 120 experts with an analysis of the problem of radium in drinking water supplies of Iowa, and requested their response to a variety of formal questions pertaining to specific issues related to the presence of radium in drinking water. Ninety-seven of the 120 responded. We observed definite preferences in responses to certain aspects of the problem, although in some cases their responses differed significantly due to such factors as length of ground-water related professional experience and residential status. When the presence of excessive radium in drinking water is identified, the respondents preferred immediate action in a world of incomplete knowledge over extensive future research; were willing to undertake personal action to seek radium-free water rather than wait for official action; and favoured local and state government involvement over federal intervention. Findings based on such exploratory surveys can be of much value in defining insightful research hypotheses for field testing. Confirmatory testing of such hypotheses to establish actual preferences in communities with excessive radium in drinking water is a valuable area for further research.     

Degradation of endocrine disruptor bisphenol A in drinking water by ozone oxidation

The ozone oxidation of endocrine disruptor bisphenol A in drinking water was investigated. A stainless completely mixed reactor was employed to carry out the degradation experiments by means of a batch model. With an initial concentration of 11.0 mg/L, the removal efficiencies of BPA (bisphenol A) could be measured up to 70%, 82%, and 90% when the dosages of ozone were 1, 1.5, and 2 mg/L, respectively. The impacts on BPA degradation under the conditions of different ozone dosages, water background values, BPA initial concentrations, and ozone adding time were analyzed. The results showed that ozone dosage plays a dominant role during the process of BPA degradation, while the impact of the contact time could be ignored. UV wavelength scanning was used to confirm that the by-products were produced, which could be absorbed at UV254. The value of UV254 was observed to have changed during the ozonation process. Based on the change of UV254, it could be concluded that BPA is not completely degraded at low ozone dosage, while shorter adding time of total ozone dosage, high ozone dosage, and improvement of dissolved ozone concentration greatly contribute to the extent of BPA degradation. The effects of applied H₂O₂ dose in ozone oxidation of BPA were also examined in this study. The O₃-H₂O₂ processes proved to have similar effects on the degradation of BPA by ozone oxidation.     

广州市饮用水中挥发性有机物的研究

饮用水中的挥发性有机化合物（VOCs）来源于水源水受到的环境污染或是在净化消毒工艺处理工程中反应产生的副产物,可对人体健康造成极大的危害。改革开放以来,广州人口和经济得到突飞猛进的发展,也带来了包括饮用水安全在内的诸多严重的社会和环境问题。虽然饮用水中VOCs的研究已经得到越来越多的重视,但是目前对广州市饮用水中挥发性有机物的研究还鲜有报道。本文在广州市中心城区选取15个不同位置的采样点进行了自来水水样采集,并利用吹扫-捕集-气相色谱-质谱（GC-MS）联用系统分析技术测定水中 VOCs 的种类和三卤甲烷的质量浓度。结果表明,广州市中心城区的自来水中VOCs有20种,以三卤甲烷（THMs）和芳香烃类为主,占了所检出的物质总量的78%以上。THMs中四种化合物（氯仿、一溴二氯甲烷、二溴一氯甲烷、溴仿）的检出率达100%,总三卤甲烷的平均质量浓度为46.46μg· L-1,最大值为53.31μg· L-1,最小值39.91μg· L-1。根据2006版国家饮用水标准,四种三卤甲烷质量浓度均低于标准限值,符合标准要求。对市面上一般的瓶装水的研究发现,瓶装水中三卤甲烷的质量浓度非常低,总三卤甲烷平均质量浓度仅为1.47μg·L-1,约是自来水中质量浓度的1/30。为了解温度及煮沸对自来水中 THMs 质量浓度的影响,本研究设计了实验进行探究。结果发现加热至沸腾过程中,THMs质量浓度随温度升高而升高,而沸腾后THMs骤降,煮沸5 min可降低水中约95%的THMs,接近瓶装水中THMs质量浓度。     

A red water occurrence in drinking water distribution systems caused by changes in water source in Beijing,China: mechanism analysis and control measures

A red water phenomenon occurred in several communities few days after the change of water source in Beijing, China in 2008. In this study, the origin of this problem, the mechanism of iron release and various control measures were investigated. The results indicated that a significant increase in sulphate concentration as a result of the new water source was the cause of the red water phenomenon. The mechanism of iron release was found that the high-concentration sulphate in the new water source disrupted the stable shell of scale on the inner pipe and led to the release of iron compounds. Experiments showed that the iron release rate in the new source water within pipe section was over 11-fold higher than that occurring within the local source water. The recovery of tap water quality lasted several months despite ameliora- tive measures being implemented, including adding phosphate, reducing the overall proportion of the new water source, elevating the pH and alkalinity, and utilizing free chlorine as a disinfectant instead of chloramine. Adding phosphate was more effective and more practical than the other measures. The iron release rate was decreased after the addition of 1.5 mg. L-1 orthophosphate- P, tripolyphosphate-P and hexametaphosphate-P by 68%, 83% and 87%, respectively. Elevating the pH and alkalinity also reduced the iron release rate by 50%. However, the iron release rate did not decreased after replacing chloramine by 0.5-0.8 mg. L-1 of free chlorine as disinfectant.     

Biofiltration and disinfection codetermine the bacterial antibiotic resistome in drinking water: A review and meta-analysis

• Published data was used to analyze the fate of ARGs in water treatment. • Biomass removal leads to the reduction in absolute abundance of ARGs. • Mechanism that filter biofilm maintain ARB/ARGs was summarized. • Potential BAR risks caused by biofiltration and chlorination were proposed. The bacterial antibiotic resistome (BAR) is one of the most serious contemporary medical challenges. The BAR problem in drinking water is receiving growing attention. In this study, we focused on the distribution, changes, and health risks of the BAR throughout the drinking water treatment system. We extracted the antibiotic resistance gene (ARG) data from recent publications and analyzed ARG profiles based on diversity, absolute abundance, and relative abundance. The absolute abundance of ARG was found to decrease with water treatment processes and was positively correlated with the abundance of 16S rRNA (r² = 0.963, p<0.001), indicating that the reduction of ARG concentration was accompanied by decreasing biomass. Among treatment processes, biofiltration and chlorination were discovered to play important roles in shaping the bacterial antibiotic resistome. Chlorination exhibited positive effects in controlling the diversity of ARG, while biofiltration, especially granular activated carbon filtration, increased the diversity of ARG. Both biofiltration and chlorination altered the structure of the resistome by affecting relative ARG abundance. In addition, we analyzed the mechanism behind the impact of biofiltration and chlorination on the bacterial antibiotic resistome. By intercepting influent ARG-carrying bacteria, biofilters can enrich various ARGs and maintain ARGs in biofilm. Chlorination further selects bacteria co-resistant to chlorine and antibiotics. Finally, we proposed the BAR health risks caused by biofiltration and chlorination in water treatment. To reduce potential BAR risk in drinking water, membrane filtration technology and water boiling are recommended at the point of use.     

Pollution magnet: nano-magnetite for arsenic removal from drinking water

Arsenic contamination in groundwater is a severe global problem, most notably in Southeast Asia where millions suffer from acute and chronic arsenic poisoning. Removing arsenic from groundwater in impoverished rural or urban areas without electricity and with no manufacturing infrastructure remains a significant challenge. Magnetite nanocrystals have proven to be useful in arsenic remediation and could feasibly be synthesized by a thermal decomposition method that employs refluxing of FeOOH and oleic acid in 1-octadecene in a laboratory setup. To reduce the initial cost of production, $US 2600/kg, and make this nanomaterial widely available, we suggest that inexpensive and accessible “everyday” chemicals be used. Here we show that it is possible to create functional and high-quality nanocrystals using methods appropriate for manufacturing in diverse and minimal infrastructure, even those without electricity. We suggest that the transfer of this knowledge is best achieved using an open source concept.     

Health importance of arsenic in drinking water and food

Arsenic is a toxic metalloid of global concern. It usually originates geogenically but can be intensified by human activities such as applications of pesticides and wood preservatives, mining and smelting operations, and coal combustion. Arsenic-contaminated food is a widespread problem worldwide. Data derived from population-based studies, clinical case series, and case reports relating to ingestion of inorganic arsenic in drinking water, medications, or contaminated food or beverages show the capacity of arsenate and arsenite to adversely affect multiple organ systems. Chronic arsenic poisoning can cause serious health effects including cancers, melanosis (hyperpigmentation or dark spots, and hypopigmentation or white spots), hyperkeratosis (hardened skin), restrictive lung disease, peripheral vascular disease (blackfoot disease), gangrene, diabetes mellitus, hypertension, and ischemic heart disease.     

Factors influencing the photodegradation of N-nitrosodimethylamine in drinking water

In order to provide basic data for practical application, photodegradation experiment of N-nitrosodimethylamine (NDMA) in aqueous solution was carried out with a low-pressure Hg lamp. Effects of the initial concentration of NDMA, solution pH, dissolved oxygen, and the presence of humic acid on NDMA photodegradation were investigated. NDMA at various initial concentrations selected in this study was almost completely photodegraded by UV irradiation within 20 min, except that at 1.07 mmol/L, NDMA could be photodegraded almost completely in the acidic and neutral solutions, while the removal efficiency decreased remarkably in the alkaline solution. Dissolved oxygen enhanced the NDMA photodegradation, and the presence of humic acid inhibited the degradation of NDMA. Depending on the initial concentration of NDMA, NDMA photodegradation by UV obeyed the pseudo-first-order kinetics. Dimethylamine, nitrite, and nitrate were detected as the photodegradation products of NDMA. ¹O₂ was found to be the reactive oxygen species present in the NDMA photodegradation process by UV, based on the inhibiting experiments using tert-butanol and sodium azide.     

Naturally occurring radionuclides in drinking water: An exercise in risk benefit analysis

The scientific background information describing the occurrence, measurement, health effects, treatment technology, risk assessment and economic consequences of the presence of naturally occurring radionuclides in drinking water are described for 60,000 public drinking water supplies. The relevant data for the occurrence of radium, uranium and radon in drinking water supplies are discussed and analysed. Radon is of importance because it is released in the process of taking showers and baths and in washing dishes and clothes. Its progeny is then inhaled, leading to the risk of lung cancer. Radium and uranium can both cause bone cancer. The range of average occurrence of natural radioactivity in drinking water is as follows:²²⁶Ra, 0.3 to 0.8 pCi L^–1;²²⁸Ra, 0.4 to 1.0 pCi L^–1; uranium, 0.3 to 2.0 pCi L^–1 and²²²Rn, 500 to 600 pCi L^–1. The estimated lifetime risks due to the mean groundwater concentrations of naturally occurring radionuclides are:²²⁶Ra and^228Ra, 1.0 10^–5; uranium, 2.0 × 10^–6 and radon, 4.0 × 10^–4. The cost to reduce total radium levels to 5.0 pCi L^–1 is about $9 million. An equivalent expenditure would be required to reduce radon levels to about 4,000 pCi L^–1, or uranium levels to about 100 pCi L^–1. The problem of maximizing the total mortality and the reduction per unit dollar outlay per unit dollar cost for the uranium/radon case is examined.The thoughts and ideas expressed in this paper are those of the authors and are not necessarily those of the US Environmental Protection Agency.This paper is published as a contribution to discussion on this problem and not as a paper providing new research data.     

Contaminants in drinking water and its mitigation using suitable adsorbents: an overview

Various options are applicable for the removal of water pollutants included reverse osmosis, ion exchange, coagulation, co-precipitation, catalytic reduction, herbal filtration, electrodialysis and adsorption. This paper deals with the sorption phenomena for the removal of pollutants from drinking water. Attempts have been made to use low cost sorbents developed by pretreatment/activation/impregnation with alkalis, acids, iron oxide, manganese dioxide, ferric chloride, alum, lime, aluminum salts with natural products/indigenous minerals viz. activated alumina, activated carbon, groundnut husk, saw dust, chemically coated sand, fly ash, zeolites, clay minerals and other plant products. Application of Freundich and Langmuir isotherms were used to assess the adsorption capacity. Equilibrium isotherms were determined at optimum temperature and pH to characterize the sorption process. Statistical parameters such as mass transfer coefficients, multiple regression analysis were applied to establish the mechanism. It is suggested that the characterization of suitable, and exhausted sorbent through the application of fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) is essential to establish its surface bonding. Scope for safety evaluation and risk assessment to human and biosphere may provide the guideline and predication to the regulatory agencies for its sustainable use and safe disposal The ecotoxicological assessment of the leachates and low cost removal technology are discussed in this paper.     

Turnover mechanisms of organic conformation on turbidity in drinking water

The turbidity variation in artificial water and samples from a water plant was investigated in the presence of organics with different relative molecular mass. The results show that recessive turbidity existed when water chemical conditions were changing. The formation of turbidity depended on organic relative molecular mass and their conformations on particles. At higher pH and lower ionic strength, the organic chains with a more extended conformation resulted in rising turbidity of the suspension. At lower pH, the reconformation of organics took place due to charge neutralization by the proton, resulting in a decline in turbidity. The addition of NaCl and MgCl₂ at pH 7.00 also resulted in a decrease of turbidity in the suspension. It is believed that the occurrence of recessive turbidity has a significant influence on the stability of water supply quality.     

Surface-enhanced Raman spectroscopy for emerging contaminant analysis in drinking water

● Definition of emerging contaminants in drinking water is introduced. ● SERS and standard methods for emerging contaminant analysis are compared. ● Enhancement factor and accessibility of SERS hot spots are equally important. ● SERS sensors should be tailored according to emerging contaminant properties. ● Challenges to meet drinking water regulatory guidelines are discussed. Emerging contaminants (ECs) in drinking water pose threats to public health due to their environmental prevalence and potential toxicity. The occurrence of ECs in our drinking water supplies depends on their physicochemical properties, discharging rate, and susceptibility to removal by water treatment processes. Uncertain health effects of long-term exposure to ECs justify their regular monitoring in drinking water supplies. In this review article, we will summarize the current status and future opportunities of surface-enhanced Raman spectroscopy (SERS) for EC analysis in drinking water. Working principles of SERS are first introduced and a comparison of SERS and liquid chromatography-tandem mass spectrometry in terms of cost, time, sensitivity, and availability is made. Subsequently, we discuss the strategies for designing effective SERS sensors for EC analysis based on five categories—per- and polyfluoroalkyl substances, novel pesticides, pharmaceuticals, endocrine-disrupting chemicals, and microplastics. In addition to maximizing the intrinsic enhancement factors of SERS substrates, strategies to improve hot spot accessibilities to the targeting ECs are equally important. This is a review article focusing on SERS analysis of ECs in drinking water. The discussions are not only guided by numerous endeavors to advance SERS technology but also by the drinking water regulatory policy.     

Aliphatic and aromatic halocarbons as potential mutagens in drinking water

Chlorinated phenols are either products of industrial chemical processes or the result of chlorination of drinking water. Often, the formation of chlorinated phenols is based upon naturally occurring phenol. The following chlorinated phenols have been selected for testing in the Ames‐test for their mutagenic activity: 3‐chlorophenol, 4‐chlorophenol, 2,3,6‐, 2,4,5‐, 2,4,6‐trichlorophenol, 4‐chloro‐2‐methylphenol and 4‐chloro‐3‐methylchlorophenol. The tester strains TA97, TA98, TA100 and TA104 were employed. All tested compounds produced mutagenic activity at least in one tester strain. The highest numbers of revertants were detected for 2,3,6‐ and 2,4,6‐trichlorophenol. But in contrast to the other substances, these two induced only frameshift mutations in presence of a metabolizing system. The evidence of their presence in drinking water and of their mutagenic activity makes them to a potential health hazard.     

肇庆市饮用水水源地环境保护之现状

总结了肇庆市城镇、乡镇和农村饮用水水源地的调查情况,深入分析了影响各水源地水质情况的原因以及产生的影响,并此提出相应的环保建议和改善措施.     

Techno-economic analysis for the electrocoagulation of fluoride-contaminated drinking water

Electrocoagulation (EC) technique was adopted for the treatment of fluoride-containing drinking water in a 3?L capacity batch reactor. Experimental investigation was carried out to observe the effect of different operating parameters, such as initial fluoride concentration, current density, inter-electrode distance, on the removal of fluoride from the fluoride-rich drinking water. Aluminum flat sheet was used as the electrode material. It was observed that with an increase in current density, percentage removal of fluoride increased. It was seen that at electrode distance of 0.005?m, removal of fluoride attained its maximum compared to the other performances obtained at different inter-electrode distances. Life time of the aluminum electrodes was estimated from the electrode corrosion observed during the experiment. Total operating cost was estimated as a combination of energy cost and electrode cost. The total operating cost was evaluated as 0.38?US$?m^?3 to remove fluoride from the solution with an initial fluoride concentration 10?mg?L^?1. Characterizations of the electrochemically generated by-products were carried out by powder X-ray diffraction, Fourier transform infra-red Raman spectroscopy, scanning electron microscopy image and corresponding elemental analysis.