Ultraviolet activation of monochloramine to treat contaminants of emerging concern: reactions, operating parameters, byproducts, and opportunities.

The presence of CECs in aquatic systems has raised significant concern since they are potentially harmful to the environment and human health. Eliminating CECs has led to the development of alternatives to treat wastewater, such as advanced oxidation processes (AOPs). The ultraviolet-mediated activation of monochloramine (UV/NH2Cl) is a novel and relatively unexplored AOPs for treating pollutants in wastewater systems. This process involves the production of amino radicals (•NH2) and chlorine radicals (Cl•) from the UV irradiation of NH2Cl. Studies have demonstrated its effectiveness in mitigating various CECs, exhibiting advantages, such as the potential to control the amount of toxic disinfection byproducts (TDBPs) formed, low costs of reagents, and low energy consumption. However, the strong influence of operating parameters in the degradation efficiency and existence of NH2Cl, the lack of studies of its use in real matrices and techno-economic assessments, low selectivity, and prolonged treatment periods must be overcome to make this technology more competitive with more mature AOPs. This review article revisits the state-of-the-art of the UV/NH2Cl technology to eliminate pharmaceutical and personal care products (PPCPs), micropollutants from the food industry, pesticides, and industrial products in aqueous media. The reactions involved in the production of radicals and the influence of operating parameters are covered to understand the formation of TDBPs and the main challenges and limitations of the UV/NH2Cl to degrade CECs. This review article generates critical knowledge about the UV/NH2Cl process, expanding the horizon for a better application of this technology in treating water contaminated with CECs.

Disinfection By-Products Formation from Chlor(am)ination of Algal Organic Matter of Chlorella sorokiniana.

Eutrophication in water reservoirs releases algal organic matter (AOM), which is an important precursor of disinfection by-products (DBPs) formed during water treatment. Chlorella sorokiniana is a microalgae which flourishes under conditions of high light intensity and temperature, thus its prevalence in algal blooms is expected to increase with climate change. However, Chlorella sorokiniana AOM has not been previously investigated as a DBP precursor. In this context, this study evaluated the effect of AOM concentration, humic acid (HA), and pH on DBP formation from chlor(am)ination of AOM Chlorella sorokiniana. DBP yields determined by linear regression for trichloromethane (TCM) and chloral hydrate (CH) were 57.9 and 46.0 µg·mg DOC-1 in chlorination, while the TCM, CH, dichloroacetonitrile (DCAN), 1,1,1-trichloropropanone (1,1,1-TCP), and chloropicrin (CPN) concentrations were 33.6, 29.8, 16.7, 2.1, and 1.2 µg·mg DOC-1 in chloramination. Chloramination reduced the formation of TCM and CH but increased CPN, DCAN, and 1,1,1-TCP yields. AOM Chlorella sorokiniana showed a higher DBP formation than 9 of 11 algae species previously investigated in the literature. At basic pH, the concentration of TCM increased while the concentration of other DBP classes decreased. Bromide was effectively incorporated into the AOM structure and high values of bromine incorporation factor were found for THM (1.81-1.89) and HAN (1.32) at 1.5 mg Br·L-1. Empirical models predicted successfully the formation of THM and HAN (R2 > 0.86). The bromide concentration had more impact in the model on the DBP formation than AOM and HA. These results provide the first insights into the DBP formation from AOM chlor(am)ination of Chlorella sorokiniana.

Toxicity of methylparaben and its chlorinated derivatives to Allium cepa L. and Eisenia fetida Sav.

Methylparaben, chloro-methylparaben, and dichloro-methylparaben were evaluated in Allium cepa at 5, 10, 50, and 100 µg/L and in Eisenia fetida at 10 and 100 µg/L. In A. cepa roots, 100 µg/L methylparaben and 50 and 100 µg/L chlorinated methylparabens reduced cell proliferation, caused cellular changes, and reduced cell viability in meristems, which caused a reduction in root growth. Furthermore, they caused drastic inhibition of catalase, ascorbate peroxidase, and superoxide dismutase; activated guaiacol peroxidase and promoted lipid peroxidation in meristematic root cells. In earthworms, after 14 days exposure to the three compounds, there were no deaths, and catalase, ascorbate peroxidase, and superoxide dismutase were not inhibited. However, guaiacol peroxidase activity and lipid peroxidation were observed in animals exposed to dichloro-methylparaben. Soils with dichloro-methylparaben also caused the escape of earthworms. It is inferred that the recurrent contamination of soils with these methylparabens, with emphasis on chlorinated derivatives, can negatively impact different species that depend directly or indirectly on soil to survive.

Use of tannin-based coagulant and chlorine dioxide in treating brewing water: reduction of trihalomethanes and impact on physicochemical and sensory quality.

This study aimed to evaluate an alternative to reduce trihalomethane (THM) formation in brewing water. THM affects the organoleptic properties of water and, consequently, the produced beer. Water treatment based on common chemicals such as alum and free chlorine could potentially form THM. Therefore, we studied the replacement of chemicals used in water treatment: aluminum sulfate by a tannin-based coagulant and sodium hypochlorite by chlorine dioxide. Experimentally, jar tests were conducted, and the role of coagulants and oxidizing agents was evaluated for: the removal of apparent color, turbidity, natural organic matter (NOM) and microorganisms; the formation of trihalomethanes (THM); and the sensory quality of the water. Using tannin-based coagulant with chlorine dioxide was associated with the lowest THM in treated water (1.7 µg/L) and higher satisfaction in the sensory analysis. However, using these chemicals make the water treatment more expensive than the current strategy. Overall, using the tannin-based coagulant and chlorine dioxide treatment is an alternative to produce water with a lower THM concentration, better physical-chemical, and sensory quality. These findings motivate further brewing experiments and a deeper economics evaluation considering the process's sustainability.

Analysis of the Metabolic Response of Planktonic Cells and Biofilms of Klebsiella pneumoniae to Sublethal Disinfection with Sodium Hypochlorite Measured by NMR.

Klebsiella pneumoniae is a pathogenic agent able to form biofilms on water storage tanks and pipe walls. This opportunistic pathogen can generate a thick layer as one of its essential virulence factors, enabling the bacteria to survive disinfection processes and thus develop drug resistance. Understanding the metabolic differences between biofilm and planktonic cells of the K. pneumoniae response to NaClO is key to developing strategies to control its spread. In this study, we performed an NMR metabolic profile analysis to compare the response to a sublethal concentration of sodium hypochlorite of biofilm and planktonic cells of K. pneumoniae cultured inside silicone tubing. Metabolic profiles revealed changes in the metabolism of planktonic cells after a contact time of 10 min with 7 mg L-1 of sodium hypochlorite. A decrease in the production of metabolites such as lactate, acetate, ethanol, and succinate in this cell type was observed, thus indicating a disruption of glucose intake. In contrast, the biofilms displayed a high metabolic heterogeneity, and the treatment did not affect their metabolic signature.

Occurrence and removal of drugs and endocrine disruptors in water supply systems in the metropolitan region of Belo Horizonte (Minas Gerais State, Brazil).

This study evaluates both the occurrence and removal of 24 compounds, including drugs and endocrine disruptors, in 8 water treatment plants (WTP) located in the metropolitan region of Belo Horizonte (Minas Gerais State, Brazil). The compounds 4-nonylphenol, 4-octylphenol, 17α-ethinylestradiol, 17ß-estradiol, acyclovir, bisphenol A, bezafibrate, caffeine, dexamethasone, diclofenac sodium, diltiazem, estrone, estriol, gemfibrozil, ibuprofen, linezolid, loratadine, losartan, metformin, naproxen, paracetamol, promethazine, propranolol and sulfamethoxazole were monitored at 3 sampling points (raw water, filtered water, treated water) over 10 or 12 collection campaigns for each WTP. The results showed that bisphenol A occurred at higher concentrations during the dry period with a maximum concentration of 3257.1 ng L-1, while the compounds 4-nonylphenol and losartan exhibited higher concentrations in the rainy period with maximum concentrations of 8577.2 ng L-1 and 705.8 ng L-1, respectively. Regarding the removal of compounds in the monitored WTPs, the clarification step demonstrated better removals for 4-nonylphenol, bisphenol-A, paracetamol, and sulfamethoxazole, whereas the disinfection step mainly removed the compounds 4-octylphenol and estrone. Margin of exposure (ME) assessment results indicated that only dexamethasone, ethinyl estradiol, diclofenac, estradiol, and estrone were classified as imminent risk or alert considering the 95th percentile concentration found in the samples of treated water.

In vitro and in vivo study of the antiparasitic effect of thymol on poultry drinking water

The current study evaluates the antiparasitic effect of thymol on reducing parasite burden, especially Cryptosporidium load, in poultry drinking water and in improving zootechnical performances of chicks. The first experiment assessed in vitro the anti-cryptosporidiumactivity of NP (thymol-based product) on drinking water samples using microscopic counting. Samples were treated by increasing concentrations of thymol (1, 2 and 4 g L-1of NP). In vivo, chicken wererandomly assigned to three groups (control and chicks consuming treated water with two concentration of thymol (1 and 2 g L-1of NP). Water treatment efficiency was evaluated on the intestinal parasitic load and zootechnical performances of animals (Body weight, body weight gain, food intake and the consumption index). In vitro the anti-cryptosporidium effect was dose dependent (p <0.05; p <0.01; p <0.001). The in vivo test showed that the intestinal parasitic load was significantly lower (p <0.05; p <0.01; p <0.001) in the group treated with 2 g L-1of NP. Additionally, results showed a significant increase (p <0.05; p <0.1; p <0.001) in the body weight and the body weight gain of treated groups during the whole rearing period compared to the control. Furthermore, treated groups represent a lower consumption index compared to the control.(AU)

Acute toxicity of disinfection by-products from chlorination of algal organic matter to the cladocerans Ceriodaphnia silvestrii and Daphnia similis: influence of bromide and quenching agent.

Algal organic matter (AOM) in water reservoirs is a worldwide concern for drinking water treatment; once it is one of the main precursors for disinfection by-products formation (DBPs). In this context, this study investigated the ecotoxicity of DBPs from chlorination of AOM to Ceriodaphnia silvestrii and Daphnia similis (Crustacea, Cladocera). The bioassays evaluated three scenarios, including the AOM extracted from Chlorella sorokiniana, the quenching condition used in the tests, and the DBPs formed after the chlorination of the two test waters with AOM (with and without bromide presence). The results showed that AOM has no toxic effects for the tested species under typical environmental concentration (5 mg∙L-1). However, since AOM is a potential precursor of DBPs, the toxicity of two test waters (TW-1 and TW-2) after the chlorination process (25 mg Cl2·L-1, for 7 days, at 20 °C) was tested. The sample with higher toxicity to the tested species was TW-1, in which chloroform and chloral hydrate were quantified (615 and 267 µg∙L-1, respectively). However, TW-2 showed lower concentration of chloroform and chloral hydrate (260 and 157 µg∙L-1, respectively), although bromodichloromethane, dibromochloromethane, and bromoform were also detected (464, 366, and 141 µg∙L-1, respectively). Although free chlorine is highly toxic to the tested species, the quenching conditions also affected the organisms' survival due to the use of ascorbic acid and the presence of reaction intermediates. Nonetheless, both species were more affected by TW-1 and TW-2 than the quenching condition. These results endorse the importance of removing the AOM before the disinfection process to avoid the formation of DBPs. In addition, ecotoxicological analyses could provide a more comprehensive assessment of water quality, especially considering the challenges of quantifying DBPs and other emerging contaminants.

Aqueous chlorination of herbicide metribuzin: Identification and elucidation of "new" disinfection by-products, degradation pathway and toxicity evaluation.

A widely used herbicide, metribuzin, was evaluated for degradation, mineralization and disinfection by-products (DBPs) formation during aqueous chlorination. In addition, to assess the toxicity effects of chlorination on metribuzin solution the following tests were performed: acute toxicity using Artemia salina nauplii; cell viability using MTT assay; estrogenicity using a re-engineered Bioluminescent Yeast Estrogen Screen (BLYES) and a constitutively bioluminescent strain (BLYR); mutagenicity and developmental toxicity using Q(SAR) methodology. Metribuzin at 10 mg·L-1 was degraded by chlorination, achieving 93% of removal at 30 min of reaction. TOC analysis showed that the herbicide does not suffer complete mineralization, even after 24 h of contact with free chlorine. Seventeen DBPs were detected and their structural formulae were elucidated by high resolution mass spectrometry. Toxicity effects for chlorinated solutions increased when compared to the unreacted metribuzin solution. DBPs were more toxic to Artemia salina nauplii, increasing around 20% on nauplii mortality. It was also observed high estrogenicity to human receptors in BLYES assays and mutagenic and developmental toxicant effects to animals and humans in Q(SAR) methodology, suggesting that DBPs are potentially more toxic than the precursor metribuzin. Metribuzin solutions at 10 mg·L-1 showed equivalent 17-ß-estradiol values ranged from 0.061 to 6.71 µg·L-1 after to be chlorinated at different reaction times.

Pre-ozonation of surface water: An effective water treatment process to reduce the risk of infection by Giardia in drinking water.

Giardia is a protozoan parasite of primary concern for the drinking water industry. High contact times are required for Giardia inactivation by chlorination, while ozonation may be effective at much lower Ct products. In this study, we have assessed the occurrence of Giardia cysts in raw water, and in chlorinated or ozonated water from a drinking water treatment plant (DWTP) in Brazil, over a 16-month period. Moreover, we analyzed the effects of primary disinfection on cysts, and calculated the infection risk caused by the occurrence of Giardia cysts in raw water, chlorinated or ozonated water. Furthermore, we assessed the correlation of Giardia cysts with indicator bacteria in raw water. Data referring to concentration of Giardia cysts in raw water showed adherence to a gamma distribution at a significance level α = 0.05. The detection frequency and the mean concentration of Giardia cysts were higher in raw water (86.6%, 26 cysts∙L-1), than in chlorinated (46.1%, 15.7 cysts·L-1) or ozonated water (43.5%, 11.1 cysts·L-1). Overall, Giardia non-viable cysts were detected more frequently in ozonated water (80%) than in chlorinated water (68.2%) or raw water (37.7%). Ozonation and chlorination resulted, respectively, in ≈27.5- and ≈13- fold reduction of Giardia infection risk, when compared to the risk calculated for raw water. Total coliform and Escherichia coli proved to be suitable surrogates to predict the occurrence of Giardia cysts in raw surface water, however, the indicator bacteria may not be suitable surrogates to predict the disinfection of Giardia cysts, as no correlation was found between indicator bacteria and Giardia cysts in treated water. To our knowledge, this is the first study reporting the efficacy of chlorine and ozone at Ct products actually applied at a full-scale drinking water treatment plant against Giardia cysts naturally occurring in the source water, i.e. real situation. Ozonation has proven more efficient than chlorination against Giardia cysts in surface water. Escherichia coli proved to be suitable surrogate to predict Giardia cysts in raw surface water.

Chlorine Reduction Kinetics and its Mass Balance in Copper Premise Plumbing Systems During Corrosion Events.

Hypochlorous acid has been reported as the main oxidant agent responsible for the corrosion of copper plumbing systems in chlorinated water supplies. However, there is little information about chlorine consumption kinetics in a combined system (i.e., with dissolved oxygen (DO) and free chlorine), as well as its complete mass balance within a copper pipe during stagnation. The results of our experiments using copper pipes filled with synthetic drinking water, with a moderate alkalinity (pH = 7.2; dissolved inorganic carbon = 80 mg as CaCO3 /L), and tested under chlorine concentrations from 0 to 8 mg/L, show that chlorine depletion is associated with pipe wall reactions (i.e., copper oxidation and scale formation processes). Free chlorine was depleted after 4 h of stagnation and its kinetic constant depend on the initial concentration, probably due to diffusion processes. Surface analysis including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and total reflection X-ray fluorescence (T-XRF) suggest chlorine precipitation, probably as CuCl. The obtained kinetics of chlorine and DO reduction would be critical for modeling and prediction of corrosion events of copper premise plumbing systems. In addition, our results indicate that the pipe's surface reactions due to corrosion induces a loss of free chlorine in the bulk water, decreasing chlorine added for disinfection and the subsequent effect on water quality.

Toxicological aspects of trihalomethanes: a systematic review.

Chlorine is considered the most used chemical agent for water disinfection worldwide. However, water chlorination can lead to by-product generation which can be toxic to humans. The present study aimed to perform a systematic review on the toxicity of trihalomethanes (THMs) through bioindicators of cytotoxicity, genotoxicity, and mutagenicity. The results showed that studies on the effects of THMs on DNA are a current research concern for evaluating the toxicity of the pure compounds and real samples involving several types including water for recreational use, reused water, and drinking water. THMs deleterious effects have been assessed using several biosystems, where the Ames test along with experimental animal models were the most cited. A wide range of THM concentrations have been tested. Nevertheless, DNA damage was demonstrated, highlighting the potential human health risk. Among the studied THMs, chloroform presented a different action mechanism when compared with brominated THMs, with the former being cytotoxic while brominated THMs (bromodichloromethane, bromoform, and dibromochloromethane) were cytotoxic, genotoxic, and mutagenic. The described evidence in this research highlights the relevance of this topic as a human health issue. Nevertheless, research aimed to represent THMs current exposure conditions in a more accurate way would be needed to understand the real impact on human health.

Relación entre la presencia de colifagos en agua para consumo humano, las lluvias y las diarreas agudas en Costa Rica / Relation between coliphages presence in drinking water, rain and acute diarrhea in Costa Rica

ResumenLa calidad del agua de consumo es una de las preocupaciones más grandes a las que se enfrentan los entes de salud. En Costa Rica, a pesar de la buena calidad de las fuentes de agua y del agua de consumo, se siguen registrando numerosos casos de diarrea anualmente. En este estudio se realizó un análisis de indicadores de contaminación virales y bacterianos, en dos comunidades del Valle Central con acueducto propio. Se analizaron en total 24 muestras de agua por cada comunidad, durante un año, 12 en la fuente de agua y 12 en el agua tratada. La frecuencia de diarreas en cada comunidad fue comparada con la calidad microbiológica del agua consumida, encontrándose ausencia de indicadores bacterianos en muestras de agua tratada, mientras que la presencia de indicadores virales en el agua de consumo (con cloro residual) se relaciona con un incremento en el número de casos de diarreas, adicionalmente se analizó el comportamiento de las diarreas de acuerdo a la precipitación promedio con el fin de observar posibles patrones de estacionalidad. Estos hallazgos respaldan la necesidad de ampliar el monitoreo de calidad microbiológica del agua con otro tipo de indicadores de contaminación que correlacionen mejor con otros agentes patógenos de transmisión hídrica, principalmente en época seca, periodo en que se observan más casos de diarrea.

AbstractThe quality of potable water is one of the most important issues of public health. In Costa Rica, in spite of having good sources of water and good quality of water for consumption, there continues to be a significant number of diarrhea cases annually. In this investigation, viral and bacterial analyses of indicators of contamination were conducted in two rural communities with their own aqueducts in the Central Valley of Costa Rica. Twenty-four samples were taken from each community during the year; 12 from the water sources and 12 from the treated waters. The frequency of diarrhea in each community was compared to the microbiological quality of the water being consumed, noting an absence of bacterial indicators in samples of treated water, while the presence of viral indicators in the water (with residual chlorine) were associated with an incremental increase in the number of cases of diarrhea. The analysis also included measurements of average monthly rainfall with the aim of observing possible associations between seasonal conditions and the incidence of diarrhea cases. These findings indicate the need to increase the monitoring of the microbiological quality of the water with other types of indicators of contamination that correlate better with other pathogens transmitted by water, especially in the dry seasons when a greater number of cases of diarrhea are observed.

Household effectiveness vs. laboratory efficacy of point-of-use chlorination.

Treatment of water at the household level offers a promising approach to combat the global burden of diarrheal diseases. In particular, chlorination of drinking water has been a widely promoted strategy due to persistence of residual chlorine after initial treatment. However, the degree to which chlorination can reduce microbial levels in a controlled setting (efficacy) or in a household setting (effectiveness) can vary as a function of chlorine characteristics, source water characteristics, and household conditions. To gain more understanding of these factors, we carried out an observational study within households in rural communities of northern coastal Ecuador. We found that the efficacy of chlorine treatment under controlled conditions was significantly better than its household effectiveness when evaluated both by ability to meet microbiological safety standards and by log reductions. Water treated with chlorine achieved levels of microbial contamination considered safe for human consumption after 24 h of storage in the household only 39-51% of the time, depending on chlorine treatment regimen. Chlorine treatment would not be considered protective against diarrheal disease according to WHO log reduction standards. Factors that explain the observed compromised effectiveness include: source water turbidity, source water baseline contamination levels, and in-home contamination. Water in 38% of the households that had low turbidity source water (<10 NTU) met the safe water standard as compared with only 17% of the households that had high turbidity source water (>10 NTU). A 10 MPN/100 mL increase in baseline Escherichia coli levels was associated with a 2.2% increase in failure to meet the E. coli standard. Higher mean microbial contamination levels were seen in 54% of household samples in comparison to their matched controls, which is likely the result of in-home contamination during storage. Container characteristics (size of the container mouth) did not influence chlorine effectiveness. We found no significant differences between chlorine treatment regimens in ability to meet the safe water standards or in overall log reductions, although chlorine dosage did modify the effect of source conditions. These results underscore the importance of measuring both source water and household conditions to determine appropriate chlorine levels, as well as to evaluate the appropriateness of chlorine treatment and other point-of-use water quality improvement interventions.

Degradacao parcial de 17-estradiol por cloracao aplicada ao tratamento da agua / Partial degradation of 17-estradiol by the chlorination applied to the treatment of water

O objetivo do estudo foi avaliar a degradação do hormônio 17β-estradiol com doses de cloro e tempos de contato comumente utilizados em estações de tratamento de água. A aplicação de cloro levou a pequenas alterações na maioria das variáveis analisadas. A concentração inicial de 17β-estradiol influenciou a remoção pelo cloro, e observou-se que o aumento da dose de cloro aumentou a remoção do 17β-estradiol até a dose de 2 mg.L-1. A maior remoção de hormônio obtida foi de 99%, e a inativação dos microrganismos indicadores, E. coli e coliformes totais foi de até 5,6 log para valores de CT maiores que 14 mg.min.L-1 .

The purpose of this study was to evaluate the degradation of the estrogen 17β-estradiol at doses of chlorine and contact times commonly used in water treatment plants. The application of chlorine led to minor changes in most parameters examined. The initial concentration of the hormone affected the removal by chlorine and was observed that increasing the dose of chlorine increased the removal of 17β-estradiol until the dose of 2 mg.L-1. The highest removal of hormone obtained was 99%, and inactivation of the indicator microorganisms, E. coli and total coliform was up to 5.6 log for values of CT greater than 14 mg.min.L-1 .

Effects of chemical agent injections on genotoxicity of wastewater in a microfiltration-reverse osmosis membrane process for wastewater reuse.

With combined microfiltration (MF)/ultrafiltration (UF) and reverse osmosis (RO) process being widely used in municipal wastewater reclamation, RO concentrate with high level genotoxicity is becoming a potential risk to water environment. In this study, wastewater genotoxicity in a MF-RO process for municipal wastewater reclamation and also the effects of chemical agent injections were evaluated by SOS/umu genotoxicity test. The genotoxicity of RO concentrate ranged 500-559 µg 4-NQO (4-nitroquinoline-1-oxide)/L and 12-22 µg 4-NQO/mg DOC, was much higher than that of RO influent. Further research suggested that Kathon biocide was a key chemical agent associated with the genotoxicity increase. Kathon biocide used in RO system was highly genotoxic in vitro and Kathon biocide retained in RO system could contribute to a higher genotoxicity of RO concentrate. Hence, treatments for biocides before discharging are necessary. Chlorination of secondary effluent could significantly decrease the genotoxicity and increasing chlorine dosage could be an efficacious method to decrease the genotoxicity of RO concentrate. According to the result of the experiment, the dosage of chlorine in dual-membrane process could be set to about 2.5 mg Cl2/L. The effect of antiscalant (2-phosphomobutane-1,2,4-tricarboxylic acid) was also investigated; it turned out to have no effect on genotoxicity.

Solução alternativa coletiva de abastecimento de água (SAC): avaliação da qualidade bacteriológica e da cloração / Alternative collective resolution for public water supply: bacteriological and chlorination quality evaluation

As águas de soluções alternativas coletivas de abastecimento (SAC) nos municípios situados no noroeste do estado de São Paulo foram avaliadas quanto à qualidade bacteriológica e ao teor de cloro residual livre (CRL), de acordo com a Portaria nº 518 do Ministério da Saúde. Entre 2004 e 2010, foram analisadas 3.564 amostras de 66 municípios da área de abrangência do Grupo de Vigilância Sanitária 29 São José do Rio Preto (GVS 29 SJRP-SP) e de 26 municípios do GVS 30-Jales. Das amostras em desacordo (1.775) da região de abrangência do GVS 29 SJRP-SP, observou-se que 1.201 (67,7 %), 1.107 (62,4 %) e 256 (14,4 %) foram não conformes, respectivamente, em pelo menos um dos seguintes parâmetros: CRL, coliformes totais e C. termotolerantes/Escherichia coli. Quanto às amostras em desacordo da região do GVS 30-Jales (317), os números foram: 104 (32,8%), 257 (81,0%) e 82 (25,9%). Considerando-se a identificação de indicadores de contaminação das águas dos SAC, este estudo fornece subsídios aos serviços de abastecimento de água e de vigilância em saúde para implementar o controle e a prevenção de doenças de transmissão e de origem hídrica e para melhoria das condições e qualidade de vida das comunidades abrangidas.(AU)

The water from alternative public supply (APS) in the northwestern municipalities of São Paulo state were evaluated on the bacteriological quality and on the free residual chlorine (FRC) contents, by following the guidelines established by Decree nº 518 of the Ministry of Health. During the period from 2004 to 2010, 3,564 samples were analyzed, which were collected from 66 municipalities in the area covered by Health Surveillance Group (GVS) 29-São José do Rio Preto (GVS 29 SJRP-SP) and from 26 municipalities of GVS 30-Jales. Among the non-complying samples from GVS 29 SJRP-SP area (1,775), 1,201 (67.7 %), 1,107 (62.4 %) and 256 (14.4 %) showed noncompliant values at least in one of the following parameters: FRC, total coliforms and thermotolerant coliforms/Escherichia coli, respectively. The noncompliant samples collected from the region covered by the GVS-30 Jales were of 104 (32.8%), 257 (81.0%) e 82 (25.9%). As the contamination indicators for drinking water from SAC were identified, this study provides support to the water supply services and to the health surveillance for implementing the control and the prevention of waterborne diseases transmission, and for improving the life conditions and quality of the covered communities.(AU)

Criticisms of chlorination: social determinants of drinking water beliefs and practices among the Tz'utujil Maya / Críticas a la cloración: factores sociales determinantes de las creencias y prácticas con respecto al agua potable de la población Maya Tz'utujil

OBJECTIVE: To explore social determinants of drinking water beliefs and practices among the Tz'utujil Maya of Santiago Atitlán, Guatemala, through analysis of demographics, socioeconomic status, memory of historical events, sensory experience, and water attitudes. METHODS: Parallel mixed (qualitative and quantitative) methods, including participant observation, in-depth interviews based on a purposive sample, and 201 semi-structured interviews based on a regional quota sample, were used to collect data from March 2007 to August 2008. Data analysis included the use of grounded theory methodology and Pearson's chi-square test for independence. RESULTS: Qualitative results based on grounded theory highlighted how memory of the Guatemalan Civil War and Hurricane Stan, attitudes about Lake Atitlán water, and the taste and smell of chlorine influenced Tz'utujil Maya drinking water beliefs. Quantitative survey results revealed that differences in ethnicity, literacy, years of schooling, distrust of the water supply during the Civil War and Hurricane Stan, and current beliefs about Lake Atitlán and tap water quality were associated with significantly different water self-treatment practices. CONCLUSIONS: In accordance with social determinants of health paradigms, demographic, socioeconomic, social, cultural, political, and historical factors continue to be significant determinants of water-related health. Public health water interventions must address inequalities related to these underlying factors in order to achieve maximum effectiveness.

OBJETIVO: Explorar los factores sociales determinantes de las creencias y prácticas con respecto al agua potable de la población maya tz'utujil, que habita en Santiago Atitlán (Guatemala), mediante el análisis de la información demográfica, la situación socioeconómica, la memoria de hechos históricos, la experiencia sensorial y las actitudes con respecto al agua. MÉTODOS: De marzo del 2007 a agosto del 2008, se recopilaron datos por medio de métodos paralelos mixtos (tanto cualitativos como cuantitativos), como la observación de participantes, entrevistas en profundidad basadas en un muestreo intencionado y 201 entrevistas semiestructuradas basadas en un muestreo por cuota regional. En el análisis de los datos se usó el método de la teoría fundamentada o muestreo teórico y la prueba de la chi al cuadrado de Pearson para la independencia. RESULTADOS: Los resultados cualitativos basados en la teoría fundamentada pusieron de relieve que los recuerdos de la guerra civil guatemalteca y del huracán Stan, las actitudes acerca del agua del Lago Atitlán, y el gusto y el olor del cloro influían las creencias de los tz'utujiles con respecto al agua potable. Los resultados cuantitativos de la encuesta indicaron que las diferencias a raíz del grupo étnico, el alfabetismo, los años de escolaridad, la desconfianza del abastecimiento de agua durante la guerra civil y el huracán Stan, y las creencias actuales acerca de la calidad del agua del Lago Atitlán y del agua de grifo estaban asociadas con prácticas de autotratamiento del agua sumamente diferentes. CONCLUSIONES: En consonancia con el paradigma de los factores sociales determinantes de la salud, los factores demográficos, socioeconómicos, sociales, culturales, políticos e históricos siguen siendo determinantes significativos de la salud en relación con el agua. Para que puedan lograr la mayor eficacia posible, las intervenciones de salud pública con respecto al agua deben abordar las desigualdades relacionadas con estos factores fundamentales.

Cáncer gástrico en Costa Rica: ¿existe o no relación con la cloración del agua para consumo humano? / Gastric cancer in Costa Rica: is there or not related to the chlorination of water for human consumption?

El cáncer gástrico, CG, es el tumor maligno con mayor mortalidad en hombres en Costa Rica. En el caso de las mujeres ocupa el segundo lugar, después del cáncer de mama. Desde el punto de vista histológico, el CG se divide en dos tipos: el primero es el "difuso" y su etiología ha sido relacionada con factores genéticos. El segundo tipo es el "intestinal", vinculado con la exposición a cancerígenos ambientales como sustancias químicas tóxicas, altitud geográfica, edad, etc. En este sentido, algunos investigadores han estudiado las posibles relaciones de factores epidemiológicos y ecológicos, como las características físico-químicas de las aguas para consumo humano, ACH, los suelos, los plaguicidas usados en los cultivos, y la ingesta de cancerígenos en la leche como el Pteridium aquilinum, helecho macho. Con respecto al ACH, a partir de 1974, se ha relacionado la cloración del agua con la formación de subproductos de la desinfección como el cloroformo y el bromoformo, llamados trihalometanos, con potencial cancerígeno para favorecer la incidencia de CG en la población. Estos hechos, aunados al sensacionalismo periodístico han provocado inseguridad e incertidumbre entre la población consumidora de aguas sometidas a cloración...

Gastric cancer (GC) is the leading cause of cancer-related mortality in Costa Rican males. After breast cancer, it is the second highest cause of cancermortality in women in Costa Rica. From a histological point-of-view, GC is divided into two types: the first isthe “diffuse” type and it has been related etiologically to genetic factors; the second type is the “intestinal”type and it has been linked to such environmental carcinogenic factors as: toxic chemical substances, geographic altitude and age. Along these lines, someresearchers have studied possible relationships bettween epidemiological and ecological factors such as, for example, physico-chemical traits of water for human consumption (ACH), soils, pesticide use as well ascarcinogen intake in milk such as Pteridium aquilinum (the so-called male fern). Regarding ACH, since 1974,water chlorination has been causally linked to formation of byproducts of disinfection like chloroform and bromoform, so-called trihalomethanes, which have a propensity for causing a higher incidence of GC in the population. These facts, along with media hype, have provoked uncertainty and doubts regarding the safety of chlorinated water among the public. With this background in mind, an exploratory-ecological epidemiological study was carried out with the explicit purpose of analyzing if there is or if there isn´t a statistically significant link between the incidence of GC and the consumptionof chlorinated water in Costa Rica. The analysis used the GC-mortality results in 458 districts during the years1999 to 2002 and the data obtained from the National Water Laboratory on the type of water (chlorinatedor not), the number of years of disinfection and the source of the water (underground, surface or mixed).For the statistical analysis, a Standardized Mortality Index (IME) and the Pearson correlation coefficient...

Aspectos Microbiológicos e Demanda de Cloro de Amostras de Água de Dessedentação de Frangos de Corte Coletadas em Bebedouros Pendulares

Seventy-two drinking water samples of broiler chickens were analyzed, eighteen from the entrance and fifty-four from the bell-shaped drinkers. The samples were submitted to the measurement of total coliforms, fecal coliforms, fecal streptococci Escherichia coli and mesophilic microorganisms, as well as the detection of Salmonella sp. and chlorine demand. The results showed a high bacteriological contamination on the first week, with the index ranging from 10³ a 10(5). There wasn’t isolation of any Salmonella strain, probably because of no existence of infected poultry in the band. The chlorine demand rate went up to high concentration, due to high accumulation of organic matter in the drinkers, reaching the top on the fifth week (98,7%), followed by a slight decrease on the sixth week (98,5%). The analyses of the results showed that bell-shaped drinkers are depreciative apparatus and inefficient as to sanitary-hygienic qualities of the water provided to broiler chickens, contributing to a higher risk of contamination by hydric pathogenes. The usage of higher lasting types of drinkers and weekly monitoring of chlorine waste in the bell-shaped drinkers was recommended, aiming to obtain a satisfactory disinfection of the water.

Foram analisadas 72 amostras da água de dessedentação de frangos de corte, 18 da entrada e 54 dos bebedouros pendulares. As amostras foram submetidas às mensurações de coliformes totais, coliformes fecais, estreptococos fecais, Escherichia coli e organismos mesófilos, além da detecção da presença de Salmonella sp e da taxa de demanda de cloro. Os resultados evidenciaram uma elevada contaminação bacteriológica, já na primeira semana, com os indicadores na ordem de 10³ a 10(5). Não houve isolamento de nenhuma cepa de Salmonella sp, provavelmente por não haver ave infectada no plantel. A taxa de demanda de cloro mostrou-se elevada, devido ao maior acúmulo de matéria orgânica nos bebedouros, com o ápice na quinta semana (98,7%), seguida de uma leve diminuição na sexta semana (98,5%). As análises dos resultados evidenciam o bebedouro pendular como um instrumento depreciativo e ineficiente em relação às qualidades higiênico-sanitárias das águas fornecidas aos frangos de corte, contribuindo para um alto risco de contaminação por patógenos de veiculação hídrica. Preconizam-se a utilização de modelos de bebedouros menos deletérios e o monitoramento semanal de cloro residual nos bebedouros pendulares, a fim de se obter uma desinfecção satisfatória da água.