Eau potable et santé publique : défis actuels et futurs
09 Jun 2006-Journal of Water Science (Université du Québec - INRS-Eau, Terre et Environnement (INRS-ETE))-Vol. 19, Iss: 2, pp 127-135
TL;DR: In this paper, the authors present six defis pour la sante publique dans le dossier de l'eau potable pour les annees futures, and conclude that le probleme de la qualite de l’eau de boisson doit etre apprehende dans une perspective mondiale.
Abstract: L’eau que nous consommons chaque jour est essentielle a la vie. Sa qualite a toujours ete un element indispensable a un environnement favorable a la sante. Actuellement, loin d’avoir ete resolu, le probleme de la qualite de l’eau de boisson est toujours une priorite de sante publique, autant dans les pays en voie de developpement que dans les pays industrialises. Ce texte presente six defis pour la sante publique dans le dossier de l’eau potable pour les annees futures : Finalement, le probleme de la qualite de l’eau potable doit etre apprehende dans une perspective mondiale.
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TL;DR: In this article, the authors focused on the removal of methylene blue (MB) from aqueous solution by adsorption (bach method) on polyacrylonitrile-co-sodium methallyl sulfonate copolymer (AN69) and polyacrylic acid (PAA) synthetic membranes which were prepared specifically for this purpose.
Abstract: The scope of this work is focused on the removal of methylene blue (MB) from aqueous solution by adsorption (bach method) on polyacrylonitrile-co-sodium methallyl sulfonate copolymer (AN69) and polyacrylic acid (PAA) synthetic membranes which were prepared specifically for this purpose. Investigations have covered membrane properties and the determination of adsorption parameters.
The immobilization of PAA chains into AN69 matrix was revealed by FTIR analysis, whereas the presence of small superficial microcavities was demonstrated by AFM scanning. Otherwise, the increase in PAA fraction (0 to 10%), in membrane composition, induces an increase in swelling ratio (12–22%) and ionic exchange capacity (0.8–1.2 meq/g). Moreover, the equilibrium adsorption capacity improves with the increase in alkalinity of initial adsorbate solution (pH = 2–11) and with the concentration (C = 20–80 mg/L). The results of kinetic adsorption show that the mechanism of adsorption is perfectly fitted by pseudo-second order (R2 = 0.999) and the isotherm adsorption follows the Freundlich isotherm (R2 = 0.98). From the different applied adsorption models, it was found that the maximum Langmuir adsorption capacity Qm was 116 mg/g and the Freundlich index of adsorption n was 2.2.
2 citations
15 Sep 2012
TL;DR: In this article, the authors propose an adaptation of l'approche contextualiste de Pettigrew (1990, 1992) to the context of coalitions, un concept propre a l’approche des reseaux de politiques publiques.
Abstract: Cet article vise la comprehension du contexte et du jeu des acteurs ayant mene a l’adoption du Reglement sur la qualite de l’eau potable. Cette initiative a permis au Quebec de se positionner parmi les Etats ayant des normes de qualite et des controles de production parmi les plus rigoureux sur le continent nord-americain. Une adaptation de l’approche contextualiste de Pettigrew (1990 ; 1992) est retenue comme cadre d’analyse. Cette approche insiste sur l’importance, au moment d’un changement, de l’interaction entre trois dimensions : le contexte, le contenu et le processus. De maniere a preciser cette derniere dimension, il est propose de recourir a l’idee de coalitions, un concept propre a l’approche des reseaux de politiques publiques. Cet apport permet de mieux cerner l’influence des organisations externes a l’appareil gouvernemental et de fournir une explication des relations entre les differentes dimensions du contextualiste.
2 citations
TL;DR: In this paper , a prospective and analytical study on three sites where hospital effluents from the intensive care unit (station A), the upstream of the wastewater treatment plant (station B), and the gynaecology, surgery and hospitalisation departments (station C) were sampled.
Abstract: The untreated effluents generated by hospital activities contribute to the dissemination of pathogenic germs and multi-resistant bacteria, thus presenting a great potential danger for health and the environment. The objective of this study was to evaluate the microbiological and physico-chemical quality of the effluents of the Yaoundé University Hospital Centre and their impact on the environment. It was a prospective and analytical study on three sites where hospital effluents from the intensive care unit (Station A), the upstream of the wastewater treatment plant (Station B), and the gynaecology, surgery and hospitalisation departments (Station C) were sampled. Samples were collected in sterile glass bottles for bacteriological analyses and polyethylene bottles for physico-chemical analyses. The bacteriological parameters measured showed that the density of the bacterial species sought was very high at Station B with a predominance of the species Escherichia coli (57.36%). At Station A, total coliforms were very abundant (50.12%) and at Station C, the genus Pseudomonas was predominant (14.69%). Bacteria of the genus Streptococcus were represented by three species, namely: Streptococcus agalactiae, Streptococcus faecalis, and Streptococcus pneumoniae. The Pseudomonas genus was also represented by 3 species, namely Pseudomonas aeruginosa, Pseudomonas maltophilia and Pseudomonas putida. The physico-chemical parameters showed that apart from temperature and conductivity, which were in compliance with the standards, the other had values higher than these standards. This study shows that untreated hospital effluent contains most of the bacteria involved in community, nosocomial infections and would be a potential source of risk to the surrounding population.
References
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TL;DR: Data indicate that for this range of exposure the safety margin appears considerable with respect to the potential carcinogenic effect of household exposure to CHCl 3, and also according to exposure scenarios that integrate drinking-water ingestion and air inhalation.
Abstract: Chloroform (CHCl3) the trihalomethane most prevalent in drinking water, is a proven animal carcinogen and a suspected human carcinogen. Consequently, standards have been issued by health authorities to limit its concentration in drinking water. These limits are based solely on ingestion, without taking into account inhalation and skin contact. Exposure to CHCl3 was assessed for 18 men (age: mean 38 years; range 23-51) following a 10-min shower in their respective residences located in the Quebec City region (Canada). CHCl3 concentration was measured in alveolar air samples collected before, immediately after, and 15 min and 30 min following the shower. Indoor air and water concentrations were determined concomitantly. Mean CHCl3 concentrations in the air of the shower stall and in water were respectively 147 microg/m3 (SD = 56.2 microg/m3) and 20.1 microg/L (SD = 9.0 microg/L). Water concentrations were comparable to those documented in a large proportion of distribution networks in Canada. The mean increase in alveolar air CHCl3 concentration (deltaCHCIALV) at the end of the shower was 33 microg/m3 (SD = 14.7 microg/m3). A multiple-regression analysis revealed that deltaCHCl3ALV values were only associated with chloroform concentration in air of the shower stall. DeltaCHCl3ALV were described using a physiologically based pharmacokinetic (PBPK) model. This model was then used to estimate concentrations of CHCl3 metabolites bound to liver and kidney macromolecules following a shower, and also according to exposure scenarios that integrate drinking-water ingestion and air inhalation. The concentration predicted in the liver following a worst-case exposure scenario was 0.41 microg CHCl3 equivalents/kg of tissue, some 6,000 times lower than the lowest concentration that did not increase the incidence of hepatic tumors in laboratory animals. Data indicate that for this range of exposure the safety margin appears therefore considerable with respect to the potential carcinogenic effect of household exposure to CHCl3.
36 citations
TL;DR: This study measured the incidence rate of calls for acute gastrointestinal illness, investigated the relationship between the frequency of calls and the turbidity of the treated water in the Quebec City drinking water plant, and evaluated the relevance and the conditions of use of the Info-Santé CLSC system for the surveillance of waterborne enteric illness.
Abstract: The increasing frequency of waterborne outbreaks demonstrates that classic indicators used for the surveillance of the microbiological quality of drinking water have several gaps and that routine public health surveillance seems insufficient to allow for the rapid detection of these outbreaks. The main objective of this study was to evaluate the possibility of using a regional health information telephone line, 'Info-Sante CLSC' (Info-Health Local Community Health Centre), for the surveillance of waterborne gastroenteritis. This study measured the incidence rate of calls for acute gastrointestinal illness (AGI) placed to the Info-Sante CLSC line, investigated the relationship between the frequency of calls for AGI placed to the Info-Sante CLSC line and the turbidity of the treated water in the Quebec City drinking water plant and evaluated the relevance and the conditions of use of the Info-Sante CLSC system for the surveillance of waterborne enteric illness. A relationship between the turbidity and the calls for AGI placed to Info-Sante CLSC line was observed. Significant time lags (11, 15 and 17 days prior to the outcome) were identified in the final model derived from a Poisson model using generalized additive models (GAM) as a time series analysis. Some recommendations to improve the system were formulated even though the system already seems to be useful for the surveillance of waterborne enteric diseases.
18 citations
TL;DR: Food and to a lesser extent water contribute to nitrate exposure in this rural setting with moderate water contamination; better predictors of endogenous nitrate production are needed to improve the ability to model nitrate body burden and estimate associated health risks.
Abstract: Nitrate exposure was investigated in a group of 187 people using well water and living in four areas of rural Quebec (Canada) with intensive agricultural activities. Nitrate intake was evaluated using a 24-h dietary recall and a food frequency questionnaire, in conjunction with a validated food database and measurements of nitrate concentrations in private wells. The total internal dose was estimated by means of the 24-h urinary nitrate excretion, while taking into account risk factors for endogenous nitrate formation. Mean (geometric) 24-h urinary nitrate excretion was 16.9 mg N for the 100 people with low groundwater contamination (mean nitrate concentration=0.18 mg N/l) and 23.3 mg N in the 87 individuals with moderate groundwater contamination (mean nitrate concentration=7.1 mg N/l). A multivariate analysis revealed that dietary nitrate intake during the last 24 h was the principal source of exposure, followed by water intake during the last 24 h. The Quetelet index was also a significant predictor of urinary excretion. The total predictive model explained only 29% of the variability in urinary nitrate excretion (R2=0.286). Neither the inflammatory status as indicated by elevated C reactive protein, the presence of Helicobacter pylori antibodies nor the occurrence of diarrhea during the last 24 h prior to urine collection were associated with urinary nitrate excretion. In conclusion, food and to a lesser extent water contribute to nitrate exposure in this rural setting with moderate water contamination. Better predictors of endogenous nitrate production are needed to improve our ability to model nitrate body burden and estimate associated health risks.
14 citations
TL;DR: How competing needs and uncertainties intersect in the development of Public Health Goals for uranium, fluoride, arsenic, perchlorate, and other highly debated chemicals are discussed is discussed.
Abstract: Dozens of chemicals, both natural and manmade, are often found in drinking water. Some, such as the natural contaminants uranium and arsenic, are well-known toxicants with a large toxicology database. Other chemicals, such as methyl tertiary-butyl ether (MTBE) from leaking fuel tanks, we learn about as we go along. For still others, such as the alkyl benzenes, there are very little available data, and few prospects of obtaining more. In some cases, chemicals are purposely added to drinking water for beneficial purposes (e.g., chlorine, fluoride, alum), which may cause a countervailing hazard. Removing all potentially toxic chemicals from the water is virtually impossible and is precluded for beneficial uses and for economic reasons. Determination of safe levels of chemicals in drinking water merges the available toxicity data with exposure and human effect assumptions into detailed hazard assessments. This process should incorporate as much conservatism as is needed to allow for uncertainty in the toxicity and exposure estimates. Possible sensitive subpopulations such as unborn children, infants, the elderly, and those with common diseases such as impaired kidney function must also be considered. However, the range of sensitivity and the variability of toxicity and exposure parameters can never be fully documented. In addition, the validity of the low-dose extrapolations, and whether the toxic effect found in animals occurs at all in humans, is never clear. This publication discusses how these competing needs and uncertainties intersect in the development of Public Health Goals for uranium, fluoride, arsenic, perchlorate, and other highly debated chemicals.
9 citations
TL;DR: The estimated safe levels and toxicological rationale for the first 26 chemicals are described here and are to be considered by the State of California in revising and developing state MCLs for chemicals in drinking water (which must not exceed federal MCLS).
Abstract: As part of a program for evaluation of environmental contaminants in drinking water, risk assessments are being conducted to develop Public Health Goals (PHGs) for chemicals in drinking water, based solely on public health considerations. California's Safe Drinking Water Act of 1996 mandated the development of PHGs for over 80 chemicals by 31 December 1999. The law allowed these levels to be set higher or lower than federal maximum contaminant levels (MCLs), including a level of zero if data are insufficient to determine a specific level. The estimated safe levels and toxicological rationale for the first 26 of these chemicals are described here. The chemicals include alachlor, antimony, benzo[a]pyrene, chlordane, copper, cyanide, dalapon, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 2,4-D, diethylhexylphthalate, dinoseb, endothall, ethylbenzene, fluoride, glyphosate, lead, nitrate, nitrite, oxamyl, pentachlorophenol, picloram, trichlorofluoromethane, trichlorotrifluoroethane, uranium and xylene(s). These risk assessments are to be considered by the State of California in revising and developing state MCLs for chemicals in drinking water (which must not exceed federal MCLs). The estimates are also notable for incorporation or consideration of newer guidelines and principles for risk assessment extrapolations.
8 citations