Contaminated Tap Water Research Articles

A Comparison Between Phragmites australis and Helianthus annuus in Chromium Phytoextraction

A comparison of chromium abatement from irrigation water, by the use of two selected plant species, Phragmites australis and Helianthus annuus, planted in chromium-contaminated soil, was studied in the present work. The above plant species were irrigated, in a continuous mode, with 10 mg CrVI/L contaminated tap water. More than 90 % of hexavalent chromium was reduced to trivalent chromium, from both plant species, as measured in the drainage water. Moreover, total chromium removal ranged from 54 % (Phragmites) to 70 % (Helianthus). After 90 days, the total chromium content of the contaminated soil dropped from 70 to 32 and 34 mg Cr/kgdry soil, for Helianthus and Phragmites, respectively. Helianthus accumulated higher amount of chromium in the roots (2,730 mg Cr/kgdry tissue) as compared to 1,800 mg Cr/kgdry tissue for Phragmites. Most of CrVI was reduced to CrIII in all plant tissues, with Phragmites showing lower affinity for CrVI reduction in the root tissues but higher chromium translocation potential from roots to stems, while Helianthus showed higher chromium translocation from roots to leaves. Toxicity effects, expressed as root growth rate inhibition, indicated that Phragmites were the most tolerant specie to chromium effects. Both plant species showed high potentialities to be used in phytoremediation installations for chromium removal.

Yeasts and yeast-like fungal contaminants of water used for domestic purposes in Jos, Nigeria

Water used for domestic purposes is ideally required to be free from contaminants. Various contaminants have frequently affected the quality of such water. Water samples were obtained from 150 sources including 72 wells, 60 streams, 17 taps, and one borehole, randomly selected from five residential areas in Jos, Nigeria. Structured questionnaires and one-to- one interview was used to obtain information on features of location and use of facilities in each area. Eighty (53.3%) water sources were contaminated, predominantly wells (70.8%). The locations (identified in code) with the highest number of contaminated sources were AGO (60.0%), GBU (56.7%) and FGD (56.7%). AGD and FGD also had the highest ratio of households to one water source (25:1). Eighty- two fungi were isolated, predominantly Candida tropicalis (23.2%), Candida lipolytica (10.9%) and Rhodotorula sp (9.7%). Candida lipolytica was the highest (42.9%) contaminant in tap water. Rhodotorula sp was found in all types of water sources sampled. Type of water source had a significant effect (P<0.05) on the presence of some fungi in the water. The residential area (Location) had a significant effect on contamination of water sources by some yeasts. Water sources for domestic use in Jos are contaminated by yeasts and yeast-like fungi. Frequency of use, exposure of the facility to dirt, and contaminations of surroundings contribute to the occurrence of fungi in water sources and, by implication, the prevalence of fungal infections.

Pseudofungal tap water contaminants in sputum cytology

Detection of contaminants in cytological smears, both intrinsic and extrinsic in origin, is an important aspect to take into account in the routine work that is carried out in Cytopathology laboratories. In many of them, tap water is commonly utilized in some steps of the Papanicolaou staining method such as hydration, rinse, and blueing. Because of its source in lakes and reservoirs, and under certain climatic circumstances (high temperatures and low rainfall), fresh water may suffer a phenomenon termed ‘‘Eutrophication’’ where, due to an overproduction of nutrients, an excessive growth of different microorganisms occurs. So, running tap water may be affected by a biological contamination and, occasionally, some types of microorganisms such as bacteria, algae, protozoa, worms, and arthropods may appear as contaminants in the cytological smears. Herein, different examples of contamination by four species of algae that were observed in sputum smears stained by the Papanicolaou method are shown. Due to their filamentous appearance, initially they were misinterpreted as uncommon fungal structures. Figure C-1A shows an elongated structure, in the shape of a chain, and consisting of 11 cylindrical/rectangular drum-like cells (10–40 3 5–20 lm in size). Each cell is joined to the next by its valvar surface. The dark tonality of the surface of some cells is due to siliceous material deposited thereon. These cells are held in a filament by means of a thin mucilaginous envelope. In this case, Melosira sp. (class Diatomeae) was the most-likely species to consider. These algae are very common in freshwater habitats, especially eutrophic waters. Because of their morphological features, this structure could be misinterpreted as arthrospores of Geotricum sp., a fungus that may cause respiratory infections in immunocompromised patients. However, arthrospores are much more rectangular in shape and less wide than alga cells, with rounded ends, variable sizes (6–12 3 3–6 lm), not always oriented in the same direction and they can appear scattered. Moreover, Geotricum produces hyaline septate hyphae which show dichotomous branching. In Figure C-1B, on a background with mucus, leukocytes, and some macrophages, there appears a very long unbranched filament (15–25lm in wide), bluish in color, with a thin cellular wall and dentated surface, formed by identical clear cells, rectangular or square in shape, and containing a round chloroplast. On the basis of these morphological features, this structure was tentatively identified as a filamentous green algae belonging to Ulothrix sp. This species is frequently found in cold oxygen-rich fresh waters, mainly in spring and summer. Absence of branching, spores, and budding phenomena are important points in order to reject the presence of fungal elements such as the conidiophore of diverse types of fungi. Figure C-1C shows a filamentous structure where the cells are connected end-to-end forming something similar to a chain. Vegetative cells (Antheridium) appear as short cylinders in shape (15–20 lm wide), and the bulb-like structures (Oogonium) located between the vegetative cells are egg cells. This structure was tentatively identified as a green algae belonging to Oedogonium sp. This species is widely distributed in all kinds of fresh water. In this case, Blastomyces dermatitidis, a fungus that can also cause pulmonary infections, should be taken into account for its differential diagnosis. The microscopic appearance of this dimorphic fungus may be like hyaline CFGS Anatomia Patologica y Citologia, Instituto de Piedras Blancas, Asturias, Spain *Correspondence to: Rafael Martinez-Giron, Ph.D., M.D., CFGS Anatomia Patologica y Citologia, Instituto de Piedras Blancas, Avda. Principal, 33. 33450-P, Plancas-Asturias, Spain. E-mail: rmartinezgiron@hotmail.com Received 7 March 2012; Revision 26 July 2012; Accepted 25 September 2012 DOI 10.1002/dc.22937 Published online 16 November 2012 in Wiley Online Library (wileyonlinelibrary.com).

Microbial contamination of contact lens storage cases and domestic tap water of contact lens wearers

Contact lenses have been widely used as an alternative to spectacles both in developed and developing countries. However, under certain circumstances, adverse responses can occur during contact lens wear and several microorganisms--including bacteria, fungi, and free living amoebae--can cause several eye infections in wearers. Extended wear of contact lenses is the major risk factor of eye infections such as microbial keratitis, besides contaminated contact lens storage case, contaminated lens care solutions, and inaccurate contact lens handling. In this study, we collected contact lens storage case and domestic tap water samples from 50 asymptomatic contact lens wearers. We determined that total aerobic mesophilic bacteria were isolated in 45 (90 %), Gram negative rod bacteria were isolated in 20 (40 %), Pseudomonas spp. were isolated in 2 (4 %) and fungi were isolated in 18 (36 %) out of 50 contact lens storage cases. Free living amoebae were not detected in investigated contact lens storage cases. At the same time, out of 50, total aerobic mesophilic bacteria were isolated in 34 (68 %), fungi were isolated in 15 (30 %) and free living amoebae were isolated in 15 (30 %) domestic tap water samples. No Gram-negative rod bacteria and Pseudomonas spp. were detected in investigated water samples. Two contact lens case samples and two tap water samples were excluded from the analysis for Pseudomonas spp. for technical reasons. According to our findings, inadequate contact lens maintenance during lens wear may result in the contamination of contact lens storage cases. This situation can lead to severe eye infections in contact lens wearers over time.

Primary Amebic Meningoencephalitis Deaths Associated With Sinus Irrigation Using Contaminated Tap Water

Naegleria fowleri is a climate-sensitive, thermophilic ameba found in the environment, including warm, freshwater lakes and rivers. Primary amebic meningoencephalitis (PAM), which is almost universally fatal, occurs when N. fowleri-containing water enters the nose, typically during swimming, and N. fowleri migrates to the brain via the olfactory nerve. In 2011, 2 adults died in Louisiana hospitals of infectious meningoencephalitis after brief illnesses. Clinical and environmental testing and case investigations were initiated to determine the cause of death and to identify the exposures. Both patients had diagnoses of PAM. Their only reported water exposures were tap water used for household activities, including regular sinus irrigation with neti pots. Water samples, tap swab samples, and neti pots were collected from both households and tested; N. fowleri were identified in water samples from both homes. These are the first reported PAM cases in the United States associated with the presence of N. fowleri in household plumbing served by treated municipal water supplies and the first reports of PAM potentially associated with the use of a nasal irrigation device. These cases occurred in the context of an expanding geographic range for PAM beyond southern tier states with recent case reports from Minnesota, Kansas, and Virginia. These infections introduce an additional consideration for physicians recommending nasal irrigation and demonstrate the importance of using appropriate water (distilled, boiled, filtered) for nasal irrigation. Furthermore, the changing epidemiology of PAM highlights the importance of raising awareness about this disease among physicians treating persons showing meningitislike symptoms.

Lead (Pb) in Tap Water and in Blood: Implications for Lead Exposure in the United States

Lead is widely recognized as one of the most pervasive environmental health threats in the United States, and there is increased concern over adverse health impacts at levels of exposure once considered safe. Lead contamination of tap water was once a major cause of lead exposure in the United States and, as other sources have been addressed, the relative contribution of lead in water to lead in blood is expected to become increasingly important. Moreover, prior research suggests that lead in water may be more important as a source than is presently believed. The authors describe sources of lead in tap water, chemical forms of the lead, and relevant U.S. regulations/guidelines, while considering their implications for human exposure. Research that examined associations between water lead levels and blood lead levels is critically reviewed, and some of the challenges in making such associations, even if lead in water is the dominant source of lead in blood, are highlighted. Better protecting populations at risk from this and from other lead sources is necessary, if the United States is to achieve its goal of eliminating elevated blood lead levels in children by 2020.

Subcellular compartmentation of strontium and zinc in mulberry idioblasts in relation to phytoremediation potential

The cellular compartmentation of heavy metals was analyzed using mulberry leaves, in which CaCO3-forming idioblasts are situated in the epidermal layer. Germinated mulberry seedlings were grown on hydroponic culture medium containing strontium (Sr), zinc (Zn), and cadmium (Cd) with and without supplemental calcium (Ca). After ten weeks of growth, toxic effects of these metals were assessed by measuring shoot length and chlorophyll content of leaves. Sr and Cd treatment at a higher dose (4mM for Sr, 25μM for Cd) resulted in signs of toxicity, whereas no distinct phytotoxicity was observed at 500μM Zn. Elemental mapping of leaves using an energy-dispersive X-ray microanalysis system fitted to variable-pressure scanning electron microscope showed that Sr and Zn were preferentially accumulated in the idioblasts and Cd was not detected in any type of leaf cell. The deposition site of Sr was confined to cell wall sacs developing in idioblasts. The Sr sink capacity in leaves was more than 30mg/g dry weight, which equaled the Ca sink capacity. Exposure of Sr+Ca led to the co-localization of Sr and Ca in the same cell wall sac, in which Ca and Sr deposition were each estimated to be 60–80ng. The localization site of Zn was cell walls of a dome-shaped protrusion (cap) of idioblasts, together with silicon (Si) originating as a contaminant in tap water used for culturing. Mulberry idioblasts were unique in showing metal-dependent distribution to two subcellular sites (cell wall sac and cap region) of idioblasts. In conclusion, mulberry plant is a candidate for phytoremediation of radiostrontium because of their Sr-hyperaccumulating capacity with sufficient leaf biomass production.

Rapid analysis of bacterial contamination of tap water using isothermal calorimetry

Highly sensitive calorimetry was evaluated for its potential for the monitoring of the bacterial contamination of drinking water. For that purpose, water samples were added to different media and bacterial growth was followed microcalorimetrically. Drinking water samples were either tested untreated or after artificial contamination with selected bacterial strains. Two bacteria, two growth media and two growth conditions (i.e. aerobic and anaerobic) were applied. Even minor initial bacterial contamination (1–100 cells mL−1) gave rise to calorimetric signals after 5–17 h growth. Calorimetry was thus faster than detection of bacterial contamination by plating on agar and inspection of colony formation, which was performed for comparison. It was further demonstrated theoretically that calorimetric detection is superior to colony detection. The heat production curves were characteristic for the strain, the medium and the growth conditions. It is hypothesized that a further refinement of the microcalorimetric method via the application of sets of specific media in combination with selective growth conditions should allow delimiting the identity of the contaminant.

Methods of Assessing the Risks Associated with Lack of Water Supplies, Water Safety Plan for National Conditions

Abstract Article shows the desire to obtain risk-control options, and bringing it to a tolerable level. Subjects were ways of managing and dealing with risk. Methods of dealing with aspects of the protection of industrial buildings and high-risk critical infrastructure vulnerability analysis methodology to the loss of integrity. Also a set method to deal with aspects of the protection of industrial buildings and high-risk critical infrastructure that is the analysis of susceptibility to loss of integrity. The article also presents the basic principles of water safety plan based on national and foreign research publications. In the next part of article WSP methodology was concluded, outlining the actions which use significantly reduces the risk of threats that could lead to supply of contaminated tap water or total interruption of its supply. In further considerations the most important steps in creating WSP were presented. In the final section the principle of modular computer system operation that is used for network management for urban water supply in Rzeszow was presented.

Occurrence of bisphenol A in surface water, drinking water and plasma from Malaysia with exposure assessment from consumption of drinking water

This study investigated the level of bisphenol A (BPA) in surface water used as potable water, drinking water (tap and bottled mineral water) and human plasma in the Langat River basin, Malaysia. BPA was present in 93% of the surface water samples at levels ranging from below limit of quantification (LOQ; 1.3ng/L) to 215ng/L while six fold higher levels were detected in samples collected near industrial and municipal sewage treatment plant outlets. Low levels of BPA were detected in most of the drinking water samples. BPA in tap water ranged from 3.5 to 59.8ng/L with the highest levels detected in samples collected from taps connected to PVC pipes and water filter devices. Bottled mineral water had lower levels of BPA (3.3±2.6ng/L) although samples stored in poor storage condition had significantly higher levels (11.3±5.3ng/L). Meanwhile, only 17% of the plasma samples had detectable levels of BPA ranging from 0.81 to 3.65ng/mL. The study shows that BPA is a ubiquitous contaminant in surface, tap and bottled mineral water. However, exposure to BPA from drinking water is very low and is less than 0.01% of the tolerable daily intake (TDI).

Performance of an electronic tongue during monitoring 2-methylisoborneol and geosmin in water samples

Abstract 2-Methylisoborneol (MIB) and geosmin (GSM) are sub products from algae decomposition and, depending on their concentration, can be toxic; otherwise, they give unpleasant taste and odor to water. For water treatment companies it is important to constantly monitor their presence in the distributed water and avoid further costumer complaints. Lower-cost and easy-to-read instrumentation would be very promising in this regard. In this study, we evaluate the potentiality of an electronic tongue (ET) system based on non-specific polymeric sensors and impedance measurements in monitoring MIB and GSM in water samples. Principal component analysis (PCA) applied to the generated data matrix indicated that this ET was capable to perform with remarkable reproducibility the discrimination of these two contaminants in either distilled or tap water, in concentrations as low as 25 ng L −1 . Nonetheless, this analysis methodology was rather qualitative and laborious, and the outputs it provided were greatly subjective. Also, data analysis based on PCA severely restricts automation of the measuring system or its use by non-specialized operators. To circumvent these drawbacks, a fuzzy controller was designed to quantitatively perform sample classification while providing outputs in simpler data charts. For instance, the ET along with the referred fuzzy controller performed with a 100% hit rate the quantification of MIB and GSM samples in distilled and tap water. The hit rate could be read directly from the plot. The lower cost of these polymeric sensors allied to the especial features of the fuzzy controller (easiness on programming and numerical outputs) provided initial requirements for developing an automated ET system to monitor odorant species in water production and distribution.

A waterborne outbreak with a single clone of Campylobacter jejuni in the Danish town of Køge in May 2010

In Denmark, large-scale waterborne outbreaks are rare. This report describes the investigation of an outbreak that occurred in the town of Køge in May 2010. The epidemiological investigation consisted of hypothesis generating telephone interviews, followed by a cohort study among approximately 20,000 residents using an online questionnaire. Odds ratios were calculated for exposures including the number of glasses of tap water consumed. Geographical spreading was assessed using a geographical information system. The microbiological investigation included cultures of stool samples and flagellin-typing. In the environmental investigation, water samples were tested for Escherichia coli and coliform counts and for DNA of Campylobacter, Enterococcus, and Bacteroides. During the outbreak investigation a water boiling order was enforced, as tap water was considered a potential source. Of 45 patients with laboratory confirmed Campylobacter infection in the municipality of Køge in May, 43 lived in the area covered by the central water supply. Of 61 patients with laboratory confirmed Campylobacter jejuni by 8 June, 50 shared a common flagellin gene type--flaA type 36 (82%). The epidemic curve from the cohort study showed a wave of diarrhoea onset from 14 to 20 May (n = 176). Among these patients, the development of diarrhoea was associated with drinking tap water with a dose-response pattern (linear increase by 2 glasses: odds ratio 1.40, 95% confidence interval 1.16-1.70). No bacterial DNA was found in water samples. These findings indicated a point source contamination of tap water with a single clone of C. jejuni which likely occurred on 12-13 May. The water boiling order was lifted on 18 June.

The reduction of perchlorate anions in tap water using a fluidized bed bioreactor

The compounds that mainly interfere with perchlorate reduction in contaminated tap water, nitrate and dissolved oxygen (DO), were reduced using a fluidized bed bioreactor. Nitrate was reduced to below the maximum level of contamination adopted by the United StatesEnvironmental Protection Agency (EPA), 10 ppm, and the percentages of nitrate were 90, 84 and 80% for concentrations (conc.) of 25, 50 and 100 ppm perchlorate, respectively, after a 6 h hydraulic retention time (HRT). The DO concentration was reduced to less than 1 mg/L, which is considered to be appropriate for the maximum rates of perchlorate anion reduction, and the percentages of DO removed were 80, 83, and 88% for 25, 50, and 100 ppm perchlorate, respectively, after a 6 h HRT. The maximum reduction for perchlorate was obtained with an HRT of 6 h for the different concentrations of perchlorate anion contamination. This result was confirmed by increase in the concentration of free chloride and decrease in the pH values for UP water. The free chloride concentrations increased to 36, 47 and 58 ppm for the 25, 50 and 100 ppm perchlorate concentration, respectively, after the 6 h HRT. The pH values decreased to 6.01, 5.8 and 6.2 for the 25, 50 and 100 ppm perchlorate concentration, respectively, after the 6 h HRT. Key words: Fluidized bed bioreactor, free chloride, granular activated carbon, water treatment, perchlorate anion.

Mercury Accumulation in Fish: The Potential Effect of Dental Amalgam Wastewater

ABSTRACT Objectives Dental amalgam discharge in the wastewater stream is a potential source of mercury (Hg) that may contaminate the soil, water and wildlife, once released without safety measures. This study aimed the total Hg accumulation in fish Carassius auratus comparing different water environments: Water from the Tietê river basin close to the metropolitan area of Bauru, Brazil; tap water contaminated with 0.5 gm/l load of dental amalgam and tap water was used as control. Study design Fish were kept in glass aquaria, each water environment consisted of 25 specimens. The inner organs and muscles were sampled at 1 hour and 28 days for total Hg accumulation analysis. Also, water samples were analyzed at 1 hour, 7, 14, 21 and 28 days through cold vapor atomic absorption spectrometry. Results Only the fish kept at water from the Tietê river and contaminated tap water had Hg detected on its sampled tissues. The highest median levels were found in inner organs: 12.36 mg/kg–Tietê river and 262.64 mg/kg–contaminated tap water. The lowest median concentrations were found in muscles: 0.13 mg/kg–Tietê river and 0.54 mg/kg–contaminated tap water. Conclusion These findings alert to the potential environmental risks of dental amalgam waste discharge. How to cite this article Pinheiro TN, Consolaro A, Sakuma A, Buzzo ML, de Carvalho MS, Duran MC. Mercury Accumulation in Fish: The Potential Effect of Dental Amalgam Wastewater. Int J Experiment Dent Sci 2012;1(2):75-80.

Occurrence dePseudomonas aeruginosadans les réseaux intérieurs : présentation d’un protocole adapté à la collecte du biofilm présent dans la robinetterie sanitaire

Pseudomonas aeruginosa is an opportunistic pathogen that naturally occurs in aquatic environments. This bacterium is adapted to oligotrophic environmental conditions and could be detected in drinking water systems. Although, water for human consumption is required to be free of any bacteria that might pose a health risk, P. aeruginosa is not included in parameters to be analyse and in a recent report the ANSES conclude that there is no proof that the normal use of contaminated drinking water can be a source of infection by oral route in the general population. This bacterium is mostly harmless for healthy people but must be regarded as a relevant opportunistic pathogen for sensitive human population especially for hospitalized people in intensive care unit. This bacterium is responsible for almost 10% of the hospital-borne infections and drinking water network inside the building is suspected to be a source and a reservoir of P. aeruginosa . Although the target level to achieve is the absence of P. aeruginosa at terminal point-of-use, several studies showed that 4.5 in 97% of water samples taken in intensive care units are contaminated by P. aeruginosa . The origin of patients’ contamination remained discussed but among exogen sources of contamination, tap water is often suspected to be a source and a reservoir for these opportunistic pathogens. Nevertheless control strategies are limited for drinking water and recurrent contamination of tap water remained unsolved. Water contamination could be explained by retrograde contamination and by colonization of taps. To better characterize the populations of P. aeruginosa present in biofilm drinking water networks, we developed a protocol to sample biofilm from taps. Assays were performed on biofilms established inside taps and on the surface of tap swirls. Mechanical action of glass beads was compared with swabbing and proved to have more efficiency in sampling biofilm on surface of tap swirls. The protocol was then adapted to sample biofilm in faucets. It consists in filling the tap to study with a mixture of sterile distilled water and borosilicate glass beads of 1 mm in diameter and then to perform a mechanical shaking of 3 minutes with a vortex. This protocol will be used to collect biofilm on terminal point-of-use and to compare occurrence of P. aeruginosa in this type of biofilm and in the biofilm established on plumbing material.

Effective prevention of Pseudomonas aeruginosa cross-infection at a cystic fibrosis centre – Results of a 10-year prospective study

Pseudomonas aeruginosa is the major pathogen in chronic lung infections of individuals with cystic fibrosis (CF). Unrelated CF patients may acquire P. aeruginosa from the environment or by cross-infection in the CF setting. We tested the efficacy of measures to prevent nosocomial acquisition of P. aeruginosa at a Paediatric CF centre in a prospective 10-year study. P. aeruginosa-positive and P. aeruginosa-negative patients were seen in alternating weeks at the outpatient clinic. Faucets were equipped with filters to prevent bacterial contamination of tap water. Serial isolates were collected since the first documentation of a P. aeruginosa-positive culture and genotyped with a multimarker microarray. During the 10-year study, the annual prevalence of patients with at least one P. aeruginosa-positive culture was 39±6% in a population of 149±12 patients. P. aeruginosa was detected for the first time in 54 patients of whom 11 patients became chronically colonised with P. aeruginosa. Transient colonisations were recorded 97 times. A nosocomial acquisition of P. aeruginosa at the CF centre probably happened in one case. The worldwide dominant clones in the global P. aeruginosa population were also the most abundant clones in the panel of 324 early CF isolates. No rare clone had expanded by nosocomial transmission. It can be concluded that cross-infection with P. aeruginosa was prevented with simple hygienic measures at a CF centre that had experienced local outbreaks of nosocomial spread among unrelated patients in the past.

Joint symptoms after a large waterborne gastroenteritis outbreak—a controlled, population-based questionnaire study

Waterborne outbreaks offer an opportunity to study joint symptoms after a simultaneous exposure. In November 2007, a gastroenteritis outbreak due to faecal contamination of tap water took place in a Finnish town. The purpose of this study was to evaluate the occurrence of joint symptoms after the outbreak. The authors conducted a controlled, population-based questionnaire survey to study the occurrence of joint symptoms within 8 weeks after the exposure. The survey covered three areas: contaminated and uncontaminated parts of the town and a control town. A total of 1000 residents were randomly selected from each area, and the joint symptoms were first analysed separately and thereafter categorized as arthritis-like if joint swelling, redness, warmth or pain in movement was reported. A total of 2123 responses could be evaluated. The overall prevalence of joint symptoms was 13.9% in the contaminated group, 4.3% in the uncontaminated group and 1.5% among the control group, and the frequency of arthritis-like symptoms in the groups was 6.7, 2.1 and 0.5%, respectively. Gastrointestinal symptoms predicted joint complaints, diarrhoea and blood in faeces being the most significant. Residing in the contaminated area was associated with any joint symptom [odds ratio (OR) = 4.0, 95% CI 1.8, 9.0] and joint pain (OR = 7.3, 95% CI 2.1, 24.8) without preceding gastroenteritis. The frequency of joint symptoms was high in the contaminated group and also increased in the uncontaminated group. Furthermore, the risk of joint symptoms was increased in the contaminated group even without gastroenteritis.

Neural tube defects in mice exposed to tap water

In May of 2006 we suddenly began to observe neural tube defects (NTDs) in embryos of untreated control mice. We hypothesized the mice were being exposed unknowingly to a teratogenic agent and investigated the cause. Our results suggested that NTDs were not resulting from bedding material, feed, strain, or source of the mice. Additionally, mice were negative for routine and comprehensive screens of pathogens. To further test whether the NTDs resulted from infectious or genetic cause localized to our facility, we obtained three strains of timed pregnant mice from commercial suppliers located in four different states. All strains and sources of mice arrived in our laboratory with NTDs, implying that commercially available mice were possibly exposed to a teratogen prior to purchase. Our investigation eventually concluded that exposure to tap water was causing the NTDs. The incidence of NTDs was greatest in purchased mice provided tap water and lowest in purchased mice provided distilled deionized water (DDI). Providing mice DDI water for two generations (F2-DDI) eliminated the NTDs. When F2-DDI mice were provided tap water from three different urban areas prior to breeding, their offspring again developed NTDs. Increased length of exposure to tap water significantly increased the incidence of NTDs. These results indicate that a contaminant in municipal tap water is likely causing NTDs in mice. The unknown teratogen appears to have a wide geographic distribution but has not yet been identified. Water analysis is currently underway to identify candidate contaminants that might be responsible for the malformations.

IN UTERO EXPOSURE TO DRINKING WATER FROM DIFFERENT SOURCES AND EARLY POSTNATAL WEIGHT GROWTH VELOCITY. RESULTS FROM THE FRENCH EDEN MOTHER-CHILD COHORT

Background and Aims: There are sparse data about the potential effects of maternal exposure to tap water contaminants during pregnancy on child development and growth. As analytical chemistry is no...

Virus contamination from operation and maintenance events in small drinking water distribution systems

We tested the association of common events in drinking water distribution systems with contamination of household tap water with human enteric viruses. Viruses were enumerated by qPCR in the tap water of 14 municipal systems that use non-disinfected groundwater. Ultraviolet disinfection was installed at all active wellheads to reduce virus contributions from groundwater to the distribution systems. As no residual disinfectant was added to the water, any increase in virus levels measured downstream at household taps would be indicative of distribution system intrusions. Utility operators reported events through written questionnaires. Virus outcome measures were related to distribution system events using binomial and gamma regression. Virus concentrations were elevated in the wells, reduced or eliminated by ultraviolet disinfection, and elevated again in distribution systems, showing that viruses were, indeed, directly entering the systems. Pipe installation was significantly associated with higher virus levels, whereas hydrant flushing was significantly associated with lower virus levels. Weak positive associations were observed for water tower maintenance, valve exercising, and cutting open a water main. Coliform bacteria detections from routine monitoring were not associated with viruses. Understanding when distribution systems are most vulnerable to virus contamination, and taking precautionary measures, will ensure delivery of safe drinking water.