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1.
The Sb leaching from polyethylene terephthalate (PET) package material into 10 different brands of still (non-carbonated) and sparkling (carbonated) Hungarian mineral water purchased in supermarkets was investigated by inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). The Sb concentration measured in PET package materials varied between 210 and 290 mg/kg. Generally, the Sb concentration of still mineral water was lower than that of sparkling in the case of identical storage time. For modelling improper storage conditions, storage time (10-950 days), temperature (22 °C-70 °C), illumination (dark vs. 23 W daylight lamp for 116 h) as well as bottle volume (0.5, 1.0 and 1.5 L) were taken into consideration. Under certain extreme light and temperature storage conditions, the Sb concentration of some samples exceeded the concentration value of 2 ng/mL. The extent of Sb leaching from the PET recipients of different brands of mineral water can differ by even one order of magnitude in experiments conducted under the same conditions. Thus, the adequate selection of the polymer used for the production of the PET bottle for the solar water disinfection (SODIS) procedure seems to ensure low Sb levels in the water samples.  相似文献   

2.
The potential migration of genotoxic compounds into mineral water stored in polyethylene terephthalate (PET) bottles was evaluated by an integrated chemical/biological approach using short-term toxicity/genotoxicity tests and chemical analysis. Six commercial brands of still and carbonated mineral water bottled in PET and in glass were stored at 40 °C for 10 days in a stove according to the standard EEC total migration test (82/711/EEC), or at room temperature in the dark. After treatment, the samples were analysed using gas-chromatography/mass spectrometry (GC/MS) to detect volatile and non-volatile compounds, the Microtox® test to evaluate potential toxicity of the samples, and three mutagenicity tests - Tradescantia and Allium cepa micronucleus tests and the Comet assay on human leukocytes - to detect their genotoxic activity.GC/MS analysis did not detect phthalates or acetaldehyde in the water samples. The Microtox® test found no toxic effects. Mutagenicity tests detected genotoxic properties of some samples in both PET and glass bottles. Statistical analyses showed a positive association between mineral content and mutagenicity (micronuclei in A. cepa and DNA damage in human leukocytes). No clear effect of treatment and PET bottle was found. These results suggest the absence of toxic compounds migrating from PET regardless of time and conditions of storage. In conclusion, bottle material and stove treatment were not associated with the genotoxic properties of the water; the genotoxic effects detected in bottled water may be related to the characteristics of the water (minerals and CO2 content).  相似文献   

3.
Adhesion of the bacteria Campylobacter jejuni and Mycobacterium avium onto polyethylene terephtalate (PET), a polymer widely used within the bottled water industry was measured in two different groundwater solutions. From this, it was found that whilst the percentage cell adhesion for a given strain did not change between groundwater types, substantial variation was obtained between the two bacterial species tested: M. avium (10-30% adhered cells) and C. jejuni (1-2%) and no major variations were measured as a function of groundwater composition for a given strain. To explain this, the interfacial electro-hydrodynamic properties of the bacteria were investigated by microelectrophoresis, with the resultant data analysed on the basis of electrokinetic theory for soft biocolloidal particles. The results obtained showed that M. avium carries a significant volume charge density and that its peripheral layer exhibits limited hydrodynamic flow permeation compared to that of C. jejuni. It was also demonstrated that steric hindrance to flow penetration and the degree of hydrophobicity within/of the outer bacterial interface are larger for M. avium cells. In line with this, the larger amount of M. avium cells deposited onto PET substrates as compared to that of C. jejuni can be explained by hydrophobic attraction and chemical binding between hydrophobic PET and outer soft surface layer of the bacteria. Hydrophobicity of PET was addressed by combining contact angle analyses and force spectroscopy using CH3-terminated AFM tip.  相似文献   

4.
High-density polyethylene pipes (HDPE), crossbonded polyethylene pipes (PEX) and polyvinyl chloride (PVC) pipes for drinking water were tested with respect to migration of volatile organic components (VOC) to water. The odour of water in contact with plastic pipes was assessed according to the quantitative threshold odour number (TON) concept. A major migrating component from HDPE pipes was 2,4-di-tert-butyl-phenol (2,4-DTBP) which is a known degradation product from antioxidants such as Irgafos 168(R). In addition, a range of esters, aldehydes, ketones, aromatic hydrocarbons and terpenoids were identified as migration products from HDPE pipes. Water in contact with HDPE pipes was assessed with respect to TON, and values > or =4 were determined for five out of seven brands of HDPE pipes. The total amount of VOC released to water during three successive test periods were fairly constant for the HDPE pipes. Corresponding migration tests carried out for PEX pipes showed that VOC migrated in significant amounts into the test water, and TON >/=5 of the test water were observed in all tests. Several of the migrated VOC were not identified. Oxygenates predominated the identified VOC in the test water from PEX pipes. Migration tests of PVC pipes revealed few volatile migrants in the test samples and no significant odour of the test water.  相似文献   

5.
Andra SS  Makris KC  Shine JP 《Water research》2011,45(20):6677-6687
Microbial-, and chemical-based burden of disease associated with lack of access to safe water continues to primarily impact developing countries. Cost-effective health risk-mitigating measures, such as of solar disinfection applied to microbial-contaminated water stored in plastic bottles have been increasingly tested in developing countries adversely impacted by epidemic water-borne diseases. Public health concerns associated with chemical leaching from water packaging materials led us to investigate the magnitude and variability of antimony (Sb) and bromine (Br) leaching from reused plastic containers (polyethylene terephthalate, PET; and polycarbonate, PC) subject to UV and/or temperature-driven disinfection. The overall objective of this study was to determine the main and interactive effects of temperature, UV exposure duration, and frequency of bottle reuse on the extent of leaching of Sb and Br from plastic bottles into water. Regardless of UV exposure duration, frequency of reuse (up to 27 times) was the major factor that linearly increased Sb leaching from PET bottles at all temperatures tested (13-47 °C). Leached Sb concentrations (∼360 ng L−1) from the highly reused (27 times) PET bottles (minimal Sb leaching from PC bottles, <15 ng L−1) did not pose a serious risk to human health according to current daily Sb acceptable intake estimates. Leached Br concentrations from both PET and PC containers (up to ∼15 μg L−1) did not pose a consumer health risk either, however, no acceptable daily dose estimates exist for oral ingestion of organo-brominated, or other plasticizers/additives compounds if they were to be found in bottled water at much lower concentrations. Additional research on potential leaching of organic chemicals from water packaging materials is deemed necessary under relevant environmental conditions.  相似文献   

6.
A declaration of conformity according to European regulation No. 10/2011 is required to ensure the safety of plastic materials in contact with foodstuffs. This regulation established a positive list of substances that are authorized for use in plastic materials. Some compounds are subject to restrictions and/or specifications according to their toxicological data. Despite this, the analysis of PET reveals some non-intentionally added substances (NIAS) produced by authorized initial reactants and additives.Genotoxic and estrogenic activities in PET-bottled water have been reported. Chemical mixtures in bottled water have been suggested as the source of these toxicological effects. Furthermore, sample preparation techniques, such as solid-phase extraction (SPE), to extract estrogen-like compounds in bottled water are controversial. It has been suggested that inappropriate extraction methods and sample treatment may result in false-negative or positive responses when testing water extracts in bioassays. There is therefore a need to combine chemical analysis with bioassays to carry out hazard assessments.Formaldehyde, acetaldehyde and antimony are clearly related to migration from PET into water. However, several studies have shown other theoretically unexpected substances in bottled water. The origin of these compounds has not been clearly established (PET container, cap-sealing resins, background contamination, water processing steps, NIAS, recycled PET, etc.).Here, we surveyed toxicological studies on PET-bottled water and chemical compounds that may be present therein. Our literature review shows that contradictory results for PET-bottled water have been reported, and differences can be explained by the wide variety of analytical methods, bioassays and exposure conditions employed.  相似文献   

7.
Investigation of assimilable organic carbon (AOC) in flemish drinking water   总被引:2,自引:0,他引:2  
The aim of the study was to investigate the drinking water supplied to majority of residents of Flanders in Belgium. Over 500 water samples were collected from different locations, after particular and complete treatment procedure to evaluate the efficiency of each treatment step in production of biologically stable drinking water. In this study assimilable organic carbon (AOC) was of our interest and was assumed as a parameter responsible for water biostability. The influence of seasons and temperature changes on AOC content was also taken into account. The AOC in most of the non-chlorinated product water of the studied treatment plants could not meet the biostability criteria of 10 mug/l, resulting in the mean AOC concentration of 50 microg/l. However, majority of the examined chlorinated water samples were consistent with proposed criteria of 50--100 microg/l for systems maintaining disinfectant residual. Here, mean AOC concentration of 72 microg/l was obtained. Granular activated carbon filtration was helpful in diminishing AOC content of drinking water; however, the nutrient removal was enhanced by biological process incorporated into water treatment (biological activated carbon filtration). Disinfection by means of chlorination and ozonation increased the water AOC concentration while the ultraviolet irradiation showed no impact on the AOC content. Examination of seasonal AOC variations showed similar fluctuations in six units with the highest values in summer and lowest in winter.  相似文献   

8.
While humans require water for life, one-sixth of our species lives without access to safe water. In Africa, the situation is particularly acute because of global warming, the progression of the Sahara desert, civil unrest and poor governance, population growth, migration and poverty. In rural areas, the lack of adequate safe water and sanitary infrastructures leaves millions with doubtful water quality, increasing the harshness of daily life. In this paper, a pilot study was conducted during the wet season on Bolama Island (Guinea-Bissau, West Africa), a UNESCO Man and the Biosphere Reserve. Twenty-eight shallow wells, supplying water to most of the population, were sampled for microbiological, physical and chemical water quality characteristics. A ten-parameter water quality index (WQI) adapted to tropical conditions was applied to compare the different wells. About 79% of the wells showed moderate to heavy fecal contamination. From the surveyed parameters, it was found that chemical contamination was less important, although all samples were acidic, with the pH averaging 5.12+/-0.08. The WQI was 43+/-4% (0%-worst; 100%-best quality), showing that the water from the majority of wells was polluted but should be suitable for domestic use after appropriate treatment. At the onset of the wet season, diarrhea represented 11.5% of all medical cases, 92.5% of which were children aged <15. This paper suggests inexpensive steps to reduce the fecal contamination and control the pH in order to increase the potability of the well water and, concomitantly, to raise the living standards of the population in one of the poorest countries of the world.  相似文献   

9.
Several researchers have reported phosphorus growth limitations of heterotrophic bacteria instead of main energy source--organic carbon. Usually this phenomenon was noticed in waters with high organic carbon content, where phosphorus concentration was deficient to maintain the growth on level suggested by high organic carbon amount. We analysed the microbially available phosphorus (MAP) and assimilable organic carbon (AOC) in several drinking waters in Flanders, Belgium. Our aim was the investigation whether organic carbon or phosphorus is the restricting nutrient in specific water and determination of the impact of some treatment processes on MAP content. We obtained a wide range of MAP concentrations being from 0.3 to 15.2 microg P-PO(4)/l in finished drinking water. In a treatment unit applying ozone, MAP was found to be the nutrient that limits bacterial growth instead of organic carbon. Moreover, ozone caused slight MAP decrease. Granular activated carbon (GAC) filtration was able to diminish further the MAP content significantly but not below a certain level. The biofilm monitor supplied with the MAP-limited water resulted in significantly lower biofilm formation rate (BFR) value than the same installation fed with AOC-limited water.  相似文献   

10.
Xuejun Guo 《Water research》2009,43(17):4327-326
Antimony occurs widely in the environment as a result of natural processes and human activity. Although antimony is similar to arsenic in chemical properties and toxicity, and a pollutant of priority interest to the USEPA and the EU, its environmental behaviors, control techniques, and even solution chemistry, are yet barely touched. In this study, antimony removal from drinking water with coagulation-flocculation-sedimentation (CFS) is comprehensively investigated with respect to the dependence of both Sb(III) and Sb(V) removal on the initial contaminant-loading level, coagulant type and dosage, pH and interfering ions. The optimum pH for Sb(V) removal with ferric chloride (FC) was observed at pH 4.5-5.5, and continuously reduced with further pH increase. Over a broad pH range from 4.0 to 10.0, effective Sb(III) removal with FC was obtained. Contrary to the effective Sb removal with FC, the degree of both Sb(III) and Sb(V) removal with aluminum sulfate (AS) was very low, indicating the impracticability of AS application for antimony removal. The presence of phosphate and humic acid (HA) markedly impeded Sb(V) removal, while exhibited insignificant effect on Sb(III) removal. The effects of coagulant type, Sb species and pH are more pronounced than the effects of coagulant dose and initial pollutant concentration. After preliminarily excluding the possibility of precipitation and the predominance of coprecipitation, the adsorption mechanism is used to rationalize and simulate Sb/FC coagulation with good result by incorporating diffuse-layer model (DLM).  相似文献   

11.
Membrane coagulation bioreactor (MCBR) for drinking water treatment   总被引:2,自引:0,他引:2  
Tian JY  Liang H  Li X  You SJ  Tian S  Li GB 《Water research》2008,42(14):3910-3920
In this paper, a novel submerged ultrafiltration (UF) membrane coagulation bioreactor (MCBR) process was evaluated for drinking water treatment at a hydraulic retention time (HRT) as short as 0.5h. The MCBR performed well not only in the elimination of particulates and microorganisms, but also in almost complete nitrification and phosphate removal. As compared to membrane bioreactor (MBR), MCBR achieved much higher removal efficiencies of organic matter in terms of total organic carbon (TOC), permanganate index (COD(Mn)), dissolved organic carbon (DOC) and UV absorbance at 254nm (UV(254)), as well as corresponding trihalomethanes formation potential (THMFP) and haloacetic acids formation potential (HAAFP), due to polyaluminium chloride (PACl) coagulation in the bioreactor. However, the reduction of biodegradable dissolved organic carbon (BDOC) and assimilable organic carbon (AOC) by MCBR was only 8.2% and 10.1% higher than that by MBR, indicating that biodegradable organic matter (BOM) was mainly removed through biodegradation. On the other hand, the trans-membrane pressure (TMP) of MCBR developed much lower than that of MBR, which implies that coagulation in the bioreactor could mitigate membrane fouling. It was also identified that the removal of organic matter was accomplished through the combination of three unit effects: rejection by UF, biodegradation by microorganism and coagulation by PACl. During filtration operation, a fouling layer was formed on the membranes surface of both MCBR and MBR, which functioned as a second membrane for further separating organic matter.  相似文献   

12.
The prevalence of water quality incidents and disease outbreaks suggests an imperative to analyse and understand the roles of operators and organisations in the water supply system. One means considered in this paper is through human reliability analysis (HRA). We classify the human errors contributing to 62 drinking water accidents occurring in affluent countries from 1974 to 2001; define the lifecycle of these incidents; and adapt Reason's ‘Swiss cheese’ model for drinking water safety. We discuss the role of HRA in human error reduction and drinking water safety and propose a future research agenda for human error reduction in the water sector.  相似文献   

13.
Free-living amoebae (FLA) are protozoa that can be found in water networks where they prey on bacteria within biofilms. Most bacteria are digested rapidly by phagocytosis, however some are able to survive within amoebae and some are even able to multiply, as it is the case for Legionella pneumophila. These resisting bacteria are a potential health problem as they could also resist to macrophage phagocytosis. Several publications already reported intra-amoebal bacteria but the methods of identification did not allow metagenomic analysis and are partly based on co-culture with one selected amoebal strain. The aim of our study was to conduct a rRNA-targeted metagenomic analysis on amoebae and intra-amoebal bacteria found in drinking water network, to provide the first FLA microbiome in environmental strains. Three sites of a water network were sampled during four months. Culturable FLA were isolated and total DNA was prepared, allowing purification of both amoebal and bacterial DNA. Metagenomic studies were then conducted through 18S or 16S amplicons sequencing. Hartmannella was by far the most represented genus of FLA. Regarding intra-amoebal bacteria, 54 genera were identified, among which 21 were newly described intra-amoebal bacteria, underlying the power of our approach. There were high differences in bacterial diversity between the three sites. Several genera were highly represented and/or found at least in two sites, underlying that these bacteria could be able to multiply within FLA. Our method is therefore useful to identify FLA microbiome and could be applied to other networks to have a more comprehensive view of intra-amoebal diversity.  相似文献   

14.
McAdam EJ  Judd SJ 《Water research》2007,41(18):4242-4250
Interest is growing in developing membrane bioreactors (MBRs) to replace ion exchange for nitrate removal from drinking water. However, few published studies have successfully managed to retain exogenous or biologically derived carbon. This study determined an optimum C:N by substrate breakthrough rather than maximum nitrate removal. By dosing 相似文献   

15.
We studied the changes in water quality and formation of biofilms occurring in a pilot-scale water distribution system with two generally used pipe materials: copper and plastic (polyethylene, PE). The formation of biofilms with time was analysed as the number of total bacteria, heterotrophic plate counts and the concentration of ATP in biofilms. At the end of the experiment (after 308 days), microbial community structure, viable biomass and gram-negative bacterial biomass were analysed via lipid biomarkers (phospholipid fatty acids and lipopolysaccharide 3-hydroxy fatty acids), and the numbers of virus-like particles and total bacteria were enumerated by SYBR Green I staining. The formation of biofilm was slower in copper pipes than in the PE pipes, but after 200 days there was no difference in microbial numbers between the pipe materials. Copper ion led to lower microbial numbers in water during the first 200 days, but thereafter there were no differences between the two pipe materials. The number of virus-like particles was lower in biofilms and in outlet water from the copper pipes than PE pipes. Pipe material influenced also the microbial and gram-negative bacterial community structure in biofilms and water.  相似文献   

16.
The quality of private water supplies within Aberdeenshire sampled between 1992 and 1998 was analysed with respect to the presence of total coliforms (TC), faecal coliforms (FC), and nitrate. Of the approximately 1750 samples analysed, which included multiple samples from larger supply categories, the individual failure rate was 41%, 30% and 15% for TC, FC and nitrate, respectively. A combined failure rate for these samples was 48%. Failure rates on microbiological grounds displayed a seasonal trend being greater during the latter half of the year. Although this observation is likely to be due to a combination of local and regional scale factors, part of the variability in failure rate was explained by a significant positive relationship with rainfall amount. Concentrations of nitrate tended to display an opposite trend with a greater number of failures occurring during the spring period and no relationship with rainfall was immediately apparent. A relatively small number of samples (< 50) failed simultaneously for both coliforms and nitrate suggesting that the mechanism responsible for the contamination differed. A similar failure rate for samples collected directly from the source (i.e. well) compared with those taken from the potable tap (usually kitchen cold water tap) suggests that it is the groundwater source itself that contributes much of the microbiological and nitrate contamination rather than a storage or supply line contamination mechanism. A more frequent and random sampling of category one F supplies suggested a greater overall failure rate, which has its own implications for deciding an appropriate sampling frequency.  相似文献   

17.
A methodology for the concentration, detection and enumeration of Salmonella from drinking water by membrane filter technique is described. A single step filtration methodology for enteroviruses and Salmonella was not possible, due to the inactivation of Salmonella at conditions necessary for concentration of enteroviruses, i.e. pH 3.5 and 9.5. Enrichment in selenite cystine broth and incubation at 37°C followed by plating on brilliant green agar provided maximum recovery of Salmonella. Out of 21 drinking water samples in Delhi, India examined during March to May 1991, three were positive for Salmonella.  相似文献   

18.
Water utilities in the Netherlands aim at controlling the multiplication of (micro-) organisms by distributing biologically stable water through biologically stable materials. Disinfectant residuals are absent or very low. To be able to assess invertebrate abundance, methods for sampling and quantifying these animals from distribution mains were optimised and evaluated. The presented method for collecting invertebrates consists of unidirectionally flushing a mains section with a flow rate of 1 ms(-1) and filtering the flushed water in two separate flows with 500 microm and 100 microm mesh plankton gauze filters. Removal efficiency from mains was evaluated in nine experiments by collecting the invertebrates removed from the mains section by intensive cleaning immediately subsequent to sampling. Of 12 taxa distinguished, all except case-building Chironomidae larvae (2%) and Oligochaeta (30%) were removed well (51-75%). Retention of invertebrates in 100 microm filters was evaluated by filtering 39 filtrates using 30 microm filters. Except for flexible and small invertebrates such as Turbellaria (13%), Nematoda (11%) and Copepoda larvae (24%), most taxa were well retained in the 100 microm filters (53-100%). During sample processing, the method for taking sub-samples with a 10 ml pipette from the suspension of samples with high sediment concentrations was found to perform well in 75% of the samples. During a 2-year national survey in the Netherlands and consecutive investigations, the method appeared to be very suitable to assess the abundance of most invertebrate taxa in drinking water distribution systems and to be practicable for relatively inexperienced sampling and lab technicians. Although the numbers of small, less abundant or sessile taxa were not accurately assessed using the method, these taxa probably should not be the primary focus of monitoring by water utilities, as consumer complaints are not likely to be caused by these invertebrates. The accuracy of quantifying small invertebrates was further improved, however, by filtering the 100microm filtrate with a 30microm mesh plankton gauze filter.  相似文献   

19.
The ability to limit regrowth in drinking water is referred to as biological stability and depends on the concentration of disinfectant residual and on the concentration of substrate required for the growth of microorganisms. The biostability curve, based on this fundamental concept of biological stability, is a graphical approach to study the two competing effects that determine bacterial regrowth in a distribution system: inactivation due to the presence of a disinfectant, and growth due to the presence of a substrate. Biostability curves are a practical, system specific approach for addressing the problem of bacterial regrowth in distribution systems. This paper presents a standardized algorithm for generating biostability curves and this will enable water utilities to incorporate this approach for their site-specific needs. Using data from pilot scale studies, it was found that this algorithm was applicable to control regrowth of HPC in chlorinated systems where AOC is the growth limiting substrate, and growth of AOB in chloraminated systems, where ammonia is the growth limiting substrate.  相似文献   

20.
The interaction of chemical, physical and biological factors that affect the fate, transport and redox cycling of manganese in engineered drinking water systems is not clearly understood. This research investigated the presence of Mn-oxidizing and -reducing bacteria in conventional water treatment plants exposed to different levels of chlorine. Mn(II)-oxidizing and Mn(IV)-reducing bacteria, principally Bacillus spp., were isolated from biofilm samples recovered from four separate drinking water systems. Rates of Mn-oxidation and -reduction for selected individual isolates were represented by pseudo-first-order kinetics. Pseudo-first-order rate constants were obtained for Mn-oxidation (range: 0.106-0.659 days−1), aerobic Mn-reduction (range: 0.036-0.152 days−1), and anaerobic Mn-reduction (range: 0.024-0.052 days−1). The results indicate that microbial-catalyzed Mn-oxidation and -reduction (aerobic and anaerobic) can take place simultaneously in aqueous environments exposed to considerable oxygen and chlorine levels and thus affect Mn-release and -deposition in drinking water systems. This has important implications for Mn-management strategies, which typically assume Mn-reduction is not possible in the presence of chlorine and oxidizing conditions.  相似文献   

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