nÃo hà / O presente trabalho tem por objetivo avaliar a formaÃÃo de compostos orgÃnicos halogenados, especificamente trihalometanos (THM), em um Sistema de Abastecimento de Ãgua que utiliza tecnologia de filtraÃÃo direta descendente, prÃ-oxidaÃÃo com diÃxido de cloro, coagulaÃÃo com cloreto de polialumÃnio, auxiliado por um polÃmero catiÃnico e desinfecÃÃo com cloro liquefeito. Priorizou-se na avaliaÃÃo o estudo dos principais parÃmetros que influenciam a formaÃÃo de trihalometanos em meio aquoso: pH do meio, tempo de contato, temperatura, concentraÃÃo de brometos e residual de cloro livre. Adicionados a estes, foram avaliados parÃmetros operacionais, como a eficiÃncia reacional do processo de produÃÃo de diÃxido por geradores instalados na EstaÃÃo, planos de controle da difusÃo dos THM por toda extensÃo da rede de abastecimento, interferÃncia das estaÃÃes climÃticas da regiÃo (quadra chuvosa e seca), a influÃncia do agente limitante no processo reacional para a produÃÃo de diÃxido de cloro, os pontos de dosagem dos oxidantes utilizados e a distribuiÃÃo dos pontos de amostragem na rede de distribuiÃÃo de Ãgua. Destes parÃmetros, destacam-se, prioritariamente, as elevadas concentraÃÃes de THM observadas na Ãgua distribuÃda, onde somente 36% das amostras coletadas apresentaram valores inferiores ao limite determinado pela Portaria 518/2004 do MinistÃrio da SaÃde. Dentre os trihalometanos identificados, verificou-se formaÃÃo mais acentuada do clorofÃrmio, seguido do bromodiclorometano, dibromoclorometano e bromofÃrmio, tendo sido o cloro o agente que mais viabilizou a formaÃÃo de subprodutos no sistema. Destes, o clorofÃrmio e o bromodiclorometano foram as espÃcies formadas em maior quantidade no perÃodo seco e, no perÃodo chuvoso, os compostos dibromoclorometano e bromofÃmio. Observou-se que o diÃxido de cloro, produzido a partir de Ãcido clorÃdico e clorato de sÃdio, conferiu residual de cloro livre ao meio, potencializando a formaÃÃo de organoclorados. Constatou-se que o tempo de detenÃÃo da Ãgua nas redes de distribuiÃÃo à um fator que contribui para a elevaÃÃo da taxa de formaÃÃo dos THM, e que os planos de amostragem nestas redes necessitam de critÃrios especÃficos de coleta. O atual cenÃrio qualitativo da Ãgua tratada em toda extensÃo do sistema de abastecimento investigado, requer brevidade em aÃÃes estratÃgicas para a mitigaÃÃo dos fatores que potencializam a formaÃÃo dos THM, evitando comprometer a saÃde pÃblica da regiÃo estudada. / This study aims to evaluate the formation of halogenated organic compounds, specifically trihalomethanes in a Water Supply System that uses direct descendant filtration technology, pre-oxidation with chlorine dioxide, coagulation with polyaluminium chloride aided by a cationic polymer. This paper considered the main parameters that influence the formation of trihalomethanes in aqueous medium, according to results of research in the specialized technical literature, namely: pH, contact time, temperature, concentration of bromide and residual chlorine. Additionally, it was evaluated a few items of operational processes that exert an influence on the potential for formation of by-products, such as reaction efficiency of the production process of dioxide by generators installed at the treatment station, plans to control the spread of the THM throughout the water supply network, the interference of the weather (rainy season and dry season), influence of the limiting agent in the reaction process to produce chlorine dioxide, the dosing points of the oxidants used and the definition of control points in the water supply network. These parameters are highlighted as a priority: the high THM concentrations observed in the water distributed, where only 36% of the samples had values below the limit determined by the existing laws of Ministry of Health. Among the trihalomethanes identified, Chloroform was most frequently detected, followed by bromodichloromethane, dibromochloromethane and bromoform, that indicates chlorine as the agent that more enables the formation of by-products in the system. The current scenario of the treated water quality all along the supply system investigated, requires strategic actions to mitigate the factors that increase the formation of THM avoiding to compromise public health in the region studied.

No description available.

Contexte. La chloration est le traitement le plus utilisé pour désinfecter l’eau distribuée à la population. Lors du traitement, des sous-produits de chloration (SPCs) se forment par réaction de la matière organique naturelle présente dans l’eau avec le chlore. Les produits les plus présents sont les trihalométhanes (THMs), les acides haloacétiques (HAAs). Des études toxicologiques (animales et in vitro) ont montré la génotoxicité et/ou carcinogénicité et la reprotoxicité de certains SPCs. Nous avons mené deux études évaluant les effets sur la santé humaine de l’exposition aux SPCs, dans le domaine du cancer et de la reproduction. Association entre exposition aux THMs et risque de cancer de la vessie : une analyse poolée de 3 études cas-témoins européennes. Cette analyse a inclus 2381 cas et 3086 témoins issus de 3 études cas-témoins (France, Espagne, Finlande). L’exposition environnementale aux SPCs a été mesurée par la concentration en THMs estimée rétrospectivement dans les réseaux de distribution d’eau au cours des 40 années de la fenêtre d’exposition. Les usages de l’eau connus sont l’ingestion, les douches et les bains, la fréquentation de piscine (étude espagnole seulement). Une relation croissante a été observée entre le niveau environnemental de THMs, la durée d’exposition à une eau de surface chlorée et le risque de cancer de la vessie, chez les hommes uniquement. Aucune association n’a été observée avec l’exposition via l’ingestion d’eau du robinet. L’exposition via les douches, les bains et la piscine est apparue liée au risque de cancer de la vessie. Trois études cas-témoins nord-américaines ont été intégrées dans une méta-régression. Aucune spécificité européenne de la relation dose-réponse n’a été mise en évidence. Une relation dose-réponse globale incluant 4351 cas et 7055 témoins a été estimée. Association entre exposition aux SPCs et risque de prématurité et de retard de croissance intra-utérin (RCIU). Cette étude est issue de la cohorte bretonne Pélagie (3400 femmes enceintes recrutées en début de grossesse entre 2002 et 2006). L’exposition pendant la grossesse a été mesurée à l’aide de 2 indicateurs : la concentration en THMs de l’eau distribuée dans les réseaux et le dosage d’un biomarqueur urinaire (acide trichloroacétique) pour un sous-échantillon de femmes (étude cas-témoins nichée). Les niveaux dans les réseaux proviennent de la base de données réglementaire SISE-Eaux. Les usages de l’eau du robinet par les femmes pendant la grossesse ont été collectés par questionnaire (quantité d’eau du robinet bue, fréquentation de la piscine, fréquence et durée des douches et des bains). Notre étude suggère une association entre l’exposition prénatale aux SPCs et le risque de RCIU. Aucune association n’est observée avec le risque de prématurité. / Background. Chlorine is the most widely used disinfectant for drinking water treatment. During treatment process, the natural organic matter present in water reacts with chlorine to form disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), the most occurring ones. Several identified DBPs were recognized carcinogens or fetotoxic in animals. We conducted two epidemiological studies to assess the health effects of human exposure to DBPs regarding cancer and reproduction. Association between THM exposure and the risk of bladder cancer: a pooled analysis of 3 European case-control studies. The study included 2381 cases and 3086 controls from 3 case-control studies (France, Finland, Spain). Environmental exposure to SPCs was measured by THM concentrations in water distribution systems, retrospectively estimated through the 40-year exposure window. Information about water uses (tap water ingestion, showers and baths, swimming-pool attendance) was available. An increased risk of bladder cancer was observed, in men only, with increasing THM concentrations in water systems and duration of exposure to chlorinated surface water. No association was observed with exposure through tap water ingestion. Exposure through showers, baths and swimming in pools (available in Spanish study only) was associated with an increased risk of bladder cancer. Three North-American case-control studies were joined to the three European ones into a meta-regression. No specific dose-response relationship was identified for European studies. A global dose-response relationship was consequently estimated, including 4351 cases and 7055 controls. Association between DBP exposure and the risk of preterm birth and Intra-Uterine Growth Retardation (IUGR). This study was conducted within the PELAGIE cohort (3400 pregnant women included in early pregnancy, in Brittany, France, between 2002 and 2006). Exposure during pregnancy was measured by 2 indicators: THM concentrations in water distribution systems and a biomarker of HAA ingestion, the level of trichloroacetic acid in maternal urine at inclusion (in a nested case-control study). The regulatory database SISE-Eaux was used to estimate THMs concentrations in the water distribution systems. Water uses during pregnancy (ingested tap water, swimming-pool attendance, showers and bath frequencies and duration) were collected with questionnaires. Our results suggest an association between prenatal exposure to DBPs (THMs and HAAs) and the risk of IUGR. No association was found with the risk of preterm birth.

The quality of raw water is deteriorating with the continuous increase in environmental pollution. Raw water is being modified to drinking water by technological processes, and it is therefore necessary to put increased demands on the efficiency of these technological processes and their possible innovation. Due to the fact that raw water is contaminated with different types of pollutants, it is necessary to continuously control the drinking water supplied to the public distribution network in order to ensure its quality. Drinking water treatment is still unable to treat the raw water perfectly, its pollution is only reduced to acceptable standards. For this reason, it is indispensable that the quality of drinking water is being checked regularly and at the same time the efficiency of individual technological processes of drinking water treatment is assessed. This includes screening analysis or eventually ecotoxicological tests. The thesis focuses on the efficiency of technological processes of drinking water treatment. Within the experimental part, samples of raw water and samples of water after each separation stage have been collected at the drinking water treatment plant in the Czech Republic. These samples have been subjected to ecotoxicological tests and screening analysis. Based on the ecotoxicological tests carried out on Thamnocephalus platyurus, Lemna minor and Vibrio fischeri, we can assume the emergence of harmful chlorinated by-products, resulting to nearly 100% mortality in T. platyurus. The results of the screening analysis carried out indicate, after the extraction of specimens by the SPE method using HPLC/MS, that the most effective method for the removal of hormonal substances is ozonization.

Introducción: La cloración de agua es usada para controlar enfermedades entéricas; sin embargo, también conlleva la formación de productos derivados que pueden dañar el epitelio respiratorio. Nuestro objetivo es evaluar si existe asociación entre el nivel de cloro residual del agua del hogar y la presencia de síntomas respiratorios y diarrea en niños menores de 5 años en el Perú. Métodos: Estudio transversal analítico basado en un análisis secundario de las cinco últimas Encuestas Demográficas y de Salud Familiar (ENDES), Perú 2015-2019. Se incluyeron menores de 5 años en cuyos hogares se realizó medición de cloro residual del agua para consumo humano. Se analizaron tres desenlaces: síntomas respiratorios sin fiebre, síntomas respiratorios con fiebre, y diarrea en los 14 días previos a la encuesta. Se obtuvieron razones de prevalencia crudas y ajustadas (RPa) empleando regresión de Poisson considerando la muestra compleja. Resultados: Se incluyeron 95631 niños, 51.2% de sexo masculino. La prevalencia de síntomas respiratorios sin fiebre fue 19.4%, de síntomas respiratorios con fiebre 14.7%, y de diarrea 11.6%. El 30.5% de hogares tuvieron niveles de cloro residual ≥0.5 mg/L, y fue no detectable en 54.6%. Niveles ≥0.5 mg/L aumentaron la probabilidad de síntomas respiratorios sin fiebre (RPa 1.09; IC95% 1.03–1.15) y redujeron presencia de diarrea (RPa 0.90; IC95% 0.84–0.96). Niveles 0.1-0.5mg/L aumentaron la probabilidad de síntomas respiratorios sin fiebre (RPa 1.10; IC95% 1.04–1.16), y redujeron diarrea (RPa 0.89; IC95% 0.83–0.96). No hubo asociación con síntomas respiratorios con fiebre. Conclusiones: Los niveles de cloro residual ≥0.5 mg/l y entre 0.1-0.5 mg/l se asociaron a mayor prevalencia de síntomas respiratorios sin fiebre, y menor prevalencia de diarrea, pero no con síntomas respiratorios con fiebre. Debería explorarse más la relación entre cloración de agua del hogar e irritación de las vías áreas en niños. / Introduction: Water chlorination is a cornerstone for enteric diseases control; however, it could also lead to disinfection-by-products formation, which may damage the respiratory epithelium. This study aims to assess association of residual chlorine levels in household water with respiratory symptoms and diarrhea in Peruvian children under 5 years old.  Methods: Cross-sectional study using data from the Demographic and Family Health Survey (ENDES) from 2015 to 2019. Subjects were children under 5 years old who had their household water tested for residual chlorine levels. Association with respiratory symptoms without fever, respiratory symptoms with fever, and diarrhea were assessed using crude and adjusted prevalence ratios (aPR) employing Poisson regression adjusted per complex sampling. Results: 95631 children were included, 51.2% males. Prevalence of respiratory symptoms without fever was 19.4%, respiratory symptoms with fever 14.7%, and diarrhea 11.6%. Households with residual chlorine levels ≥0.5 mg/L were 30.5%; and 54.6% had non-detectable levels. Levels ≥0.5 mg/L were associated with higher prevalence of respiratory symptoms without fever (aPR 1.09; 95%CI 1.03–1.15) and less diarrhea (aPR 0.90; 95%CI 0.84–0.96). Levels 0.1-0.5mg/L were associated with higher prevalence of respiratory symptoms without fever (aPR 1.10; 95%CI 1.04–1.16) and less diarrhea (aPR 0.89; 95%IC95 0.83–0.96). There was no association with respiratory symptoms with fever. Conclusions: Residual chlorine levels ≥0.5 mg/L and between 0.1-0.5 mg/L were associated with higher prevalence of respiratory symptoms without fever, and with less prevalence of diarrhea, but not with respiratory symptoms accompanied by fever. Relationship between household water chlorination and airway irritation in children should be further explored. / Tesis