Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 9.577
Filtrar
1.
Chemosphere ; 240: 124826, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31561164

RESUMO

The processes that control water quality improvement during artificial recharge (filtering, degradation, and adsorption) can be enhanced by adding a reactive barrier containing different types of sorption sites and promoting diverse redox states along the flow path, which increases the range of pollutants degraded. While this option looks attractive for renaturazing reclaimed water, three issues have to be analyzed prior to broad scale application: (1) a fair comparison between the system with and without reactive barrier; (2) the role of plants in prevention of clogging and addition of organic carbon; and (3) the removal of pathogens. Here, we describe a pilot installation built to address these issues within a waste water treatment plant that feeds on water reclaimed from the secondary outflow. The installation consists of six systems of recharge basin and aquifer with some variations in the design of the reactive barrier and the heterogeneity of the aquifer. We report preliminary results after one year of operation. We find that (1) the systems are efficient in obtaining a broad range of redox conditions (at least iron and manganese reducing), (2) contaminants of emerging concern are significantly removed (around 80% removal, but very sensitive to the compound), (3) pathogen indicators (E. coli and Enterococci) drop by some 3-5 log units, and (4) the recharge systems maintained infiltration capacity after one year of operation (only the system without plants and the one without reactive barrier displayed some clogging). Overall, the reactive barrier enhances somewhat the performance of the system, but the gain is not dramatic, which suggests that barrier composition needs to be improved.

2.
Water Res ; 168: 115153, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655441

RESUMO

A suite of biomarkers, including amino acids, pigments, and lignin phenols coupled with high resolution mass spectrometry were used to evaluate differences in the sources and fate of organic matter (OM) in Everglades treatment wetlands as a model for OM cycling in shallow water wetlands. Five components of the system (water column particulate matter, vertical traps, flocculent material, periphyton, and surface soil) were assessed for OM transformations down-profile (i.e. water column to soil) and between treatment cells dominated by emergent aquatic vegetation (EAV) and submerged aquatic vegetation (SAV), with comparisons to reference sites within the remnant Everglades. We found that OM cycling is fundamentally different between EAV and SAV wetlands, and that SAV wetlands have some shared characteristics with similar habitats in the remnant Everglades. Other than locations densely populated by Typha spp., water column particulate organic C was predominantly derived from microbial/cryptomonad sources, rather than macroscopic sources (vascular plants and algal mats). Bacterial amino acid biomarkers were positively correlated with amino acid degradation indices and organic P (Po), respectively suggesting that microbial abundance is associated with less degraded OM, and that further investigation into relationships between microbial biomass and Po is warranted. Overall, this multi-biomarker approach can elucidate the relative degradation of OM pools, identify sources of OM, and highlight the importance of water column processes in shallow water wetlands.


Assuntos
Purificação da Água , Áreas Alagadas , Biomarcadores , Plantas , Solo
3.
Water Res ; 168: 115144, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31605830

RESUMO

Bromide and natural organic matter (NOM) are both precursors of halogenated disinfection byproducts (DBPs) in drinking water. During drinking water treatment process, chloride-form anion-exchange resin adsorption is expected to be capable of removing these DBP precursors and in the meantime releasing chloride ions. The released chloride as well as the chloride initially present in source water could be oxidized through electrolysis to generate free chlorine for disinfection. Based on the above assumptions, we developed a new disinfection approach using chloride-form anion-exchange resin adsorption followed by electrolysis to control halogenated DBPs. Parameter setup and optimization were performed for resin adsorption and electrolysis processes. Results showed that 93.7% of NOM and 90% of bromide could be removed at a resin dose of 20 mL per 2 L of simulated source water sample with a contact time of 1 h. Meanwhile, 49.5 mg/L of chloride was released from the resin to the water sample via anion-exchange, and the released chloride was further oxidized by electrolysis (Ti/RuO2-IrO2 anode and graphite cathode, current intensity of 0.4 A) to generate free chlorine (5 mg/L as Cl2) within 192 s. With this new approach, formation of total organic halogen, four trihalomethanes, and five haloacetic acids was reduced by 86.4%, 98.5%, and 93.2%, respectively, compared with chemical chlorination alone. Although the new approach might enhance the formation of some phenolic DBPs by decreasing bromide levels in source water, the overall cytotoxicity of the water samples treated with the new approach was significantly decreased by 68.8% according to a human hepatoma cell cytotoxicity assay. Notably, disinfection ability evaluation showed that the new approach achieved 3.36-log10 reductions of three seeded bacteria (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) in 19 s, suggesting that it was not only effective to E. coli but also effective to the chlorine-resistant bacteria (P. aeruginosa and S. aureus).


Assuntos
Desinfetantes , Água Potável , Poluentes Químicos da Água , Purificação da Água , Adsorção , Desinfecção , Eletrólise , Escherichia coli , Halogenação , Humanos , Staphylococcus aureus
4.
Water Res ; 168: 115148, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31622912

RESUMO

Biological ion exchange (BIEX) has proved to remove natural organic matter (NOM) better than biological activated carbon (BAC). This raises the question if BIEX can be integrated into a full-scale drinking water treatment plant to remove NOM and ammonia. In this study, a pilot plant consisting of one BIEX filter, three GAC filters and one BAC filter was set up as second-stage filtration at the Sainte-Rose drinking water treatment plant (Laval, Canada). The pilot plant was operated for a period of nine months without regeneration of the ion exchange resins. The influent water showed low DOC (2.5 mg/L) and high sulfate concentrations (28.2 mg/L). Except of a short peak of DOC released at about 1 000 BV, the BIEX filter achieved a nearly constant removal of 29-36% over the whole study period. The DOC removals of GAC were similar to BIEX at < 8000 BV but then stabilized at 13-24% after 8 000 BV. Most DOC removal in the BIEX filter was achieved at the top 30 cm layer (81%) compared to 62-66% removal in the GAC/BAC filters in the same layer. After the rapid exhaustion of the primary ion exchange capacity (<1 000 BV), sulfate displaced the fraction of NOM with lower affinity than sulfate, corresponding to the initial DOC release in the BIEX filter. The fraction of NOM with higher affinity than sulfate can still replace sulfate, which explains the good long-term performance of the BIEX filter. BIEX released ammonia with an average of 15% in warm water condition, probably related to the small diameter of the column which limited backwash effectiveness.


Assuntos
Água Potável , Poluentes Químicos da Água , Purificação da Água , Canadá , Carvão Vegetal , Filtração , Troca Iônica
5.
Water Res ; 168: 115146, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31627136

RESUMO

An energy recovery technique using a high-current bi-directional dc-dc converter for membrane capacitive de-ionization (mCDI) of brackish waters is described and it's performance assessed in a pilot-scale prototype. The energy recovery system is shown to reduce the energy consumption of the pilot-scale mCDI unit, powered by photovoltaics and with battery storage, by between 30 and 40%. Use of a stopped flow process also enables water recovery of up to 87%. The contributions to energy consumption in the system are quantified with the insights gained from this analysis enabling the selection of an optimum voltage range for desorption termination that maximizes the daily recovered energy. The experimental results demonstrate that energy usage by the mCDI process of lower than 0.4 kWh/m3 is achievable with almost 40% of the energy supplied by the batteries recovered.


Assuntos
Purificação da Água , Adsorção , Eletrodos , Membranas Artificiais , Águas Salinas , Cloreto de Sódio
6.
Environ Monit Assess ; 191(12): 729, 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31705319

RESUMO

Managers of water quality and water monitoring programs are often faced with constraints in terms of budget, time, and laboratory capacity for sample analysis. In such situation, the ideal solution is to reduce the number of sampling sites and/or monitored variables. In this case, selecting appropriate monitoring sites is a challenge. To overcome this problem, this study was conducted to statistically assess and identify the appropriate sampling stations of monitoring network under the monitored parameters. To achieve this goal, two sets of water quality data acquired from two different monitoring networks were used. The hierarchical agglomerative cluster analysis (HACA) were used to group stations with similar characteristics in the networks, the time series analysis was then performed to observe the temporal variation of water quality within the station clusters, and the geo-statistical analysis associated Kendall's coefficient of concordance were finally applied to identify the most appropriate and least appropriate sampling stations. Based on the overall result, five stations were identified in the networks that contribute the most to the knowledge of water quality status of the entire river. In addition, five stations deemed less important were identified and could therefore be considered as redundant in the network. This result demonstrated that geo-statistical technique coupled with Kendall's coefficient of concordance can be a reliable method for water resource managers to identify appropriate sampling sites in a river monitoring network.

7.
Pan Afr Med J ; 33: 244, 2019.
Artigo em Francês | MEDLINE | ID: mdl-31692810

RESUMO

Introduction: Access to drinking water and sanitation has been a long-standing issue between many States. However, it represents a daily struggle for hundreds of thousands of city dwellers who live mainly in the developing countries. The government of Cameroon with the assistance of providers of funds have implemented strategies to make sanitation and access to safe drinking water a reality. We have therefore decided to assess sanitation and access to drinking water in Douala V sub division. Method: We conducted a cross-sectional descriptive study from May to June 2018. We used a two-stage random sampling. Data were collected using a questionnaire. The analysis was conducted using Epi Info Version 7.1.3.3. Results: Our study shows that 22.47% of subjects discharged waters into the natural environment after use. Then, 65,55% (493/752) of households consumed borehole water; 53.69% of households rode between 1 to 5 km, 49.25% walked more than 15 minutes to collect water and 85,50% of households did not use a water treatment method. Only 14.49% of subjects used a water treatment method. No household used solar water disinfection (SODIS); 2/752 households (0.26%) had no latrine. Most of the households (54.52%; 410/752) discharged domestic wastes onto the street. Conclusion: The creation of decentralized units: the drillings, waste disposal systems and water treatment education to meet basic needs are essential.


Assuntos
Água Potável/normas , Saneamento/normas , Abastecimento de Água/normas , Camarões , Estudos Transversais , Países em Desenvolvimento , Desinfecção/métodos , Características da Família , Feminino , Humanos , Masculino , Inquéritos e Questionários , Toaletes/estatística & dados numéricos
8.
Water Res ; 169: 115209, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31669904

RESUMO

Lead contamination in municipal drinking water is a national public health issue and is generally the result of water contact with leaded distribution piping and on premise plumbing. As a result, the US Environmental Protection Agency's Lead and Copper Rule requires point of use sampling methods at a small fraction of consumer taps on the public water distribution system. While this approach is practical, it leaves large gaps of consumers without direct monitoring and protection. In response, a novel contest-based crowdsourcing study was conducted to engage the public in monitoring their own water quality at their home taps and study factors that shaped participation in drinking water monitoring. Participants were asked to collect samples of their household drinking water through social media postings, kiosks, and community events with the chance to win a cash prize. The project distributed approximately 800 sampling packets and received 147 packets from participants of which 93% had at least partially completed surveys. On average, private wells were found to have higher lead levels than the public water supply, and the higher lead levels were not attributed to older building age. There is also no statistical relevance between the participants' perceived and actual tap water quality. Survey responses indicated that citizens were motivated to participate in the project due to concerns about their own health and/or the health of their families. In contrast, participants reported that they were not motivated by the cash prize. This project helps inform future public engagement with water quality monitoring, create new knowledge about the influence of personal motivations for participation, and provide recommendations to help increase awareness of water quality issues.

9.
J Environ Manage ; 255: 109869, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31760297

RESUMO

The optimization of drinking water monitoring becomes increasingly complex with the size of a water distribution system. Municipal water managers have to combine their experiences with different types of information (historical water quality variability, infrastructure, water residence times, sociodemographic profiles, etc.) that are available in different forms (qualitative, quantitative, geographical, etc.) to be able to select the monitoring locations for regulatory compliance and routine water quality management and control. Therefore, the integration of such information requires to select suitable variables and use the appropriate data mining and aggregation methods. This work aims to develop a methodology that helps optimize drinking water quality monitoring programs by considering the different components of population vulnerability that vary both spatially and temporally. This project was conducted in a distribution system that supplies approximately 510 000 citizens. Due to the high seasonal climatic variations and the size of the network, there are also considerable spatial and temporal variations in water quality throughout the year. An index representing the spatio-temporal population vulnerability (combination of population exposure, sensitivity and adaptation capacity) to the degradation of drinking water quality was developed by selecting the relevant parameters and aggregation methods. The population vulnerability index was calculated by aggregating spatio-temporal water quality data (representing microbiological and chemical risks) and distribution network characteristics (number of leakages, pipes type and age). This information was then compared with sociodemographic data related to population sensitivity (percentage of children and the elderly, and the number of health care centers) and the population's adaptive capacity (social and material deprivation). A fuzzy synthetic evaluation method is used for parameter aggregation and to calculate the different indexes. By considering variable locations and periods of time that may better represent the population vulnerability, the results of this project are useful for drinking water managers to optimize their drinking water monitoring strategies.

10.
Sci Total Environ ; 695: 133923, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31756855

RESUMO

Peri-urban aquacultures produce nutritious food in proximity to markets, but poor surface water quality in rapidly expanding megacities threatens their success in emerging economies. Our study compared, for a wide range of parameters, water quality downstream of Bangkok with aquaculture regulations and standards. For parameters not meeting those requirements, we sought to establish whether aquaculture practice or external factors were responsible. We applied conventional and advanced methods, including micropollutant analysis, genetic markers, and 16S rRNA amplicon sequencing, to investigate three family-owned aquacultures spanning extensive, semi-intensive and intensive practices. Canals draining the city of Bangkok did not meet quality standards for water to be used in aquaculture, and were sources for faecal coliforms, Bacteriodes, Prevotella, Human E. coli, tetracycline resistance genes, and nitrogen into the aquaculture ponds. Because of these inputs, aquacultures suffered algae blooms, with and without fertilizer and feed addition to the ponds. The aquacultures were sources of salinity and the herbicide diuron into the canals. Diuron was detectable in shrimp, but not at a level of concern to human health. Given the extent and nature of pollution, peri-urban water policy should prioritize charging for urban wastewater treatment over water fees for small-scale agricultural users. The extensive aquaculture attenuated per year an estimated twenty population equivalents of nitrogen pollution and trillions of faecal coliform bacteria inputs from the canal. Extensive aquacultures could thus contribute to peri-urban blue-green infrastructures providing ecosystem services to the urban population such as flood risk management, food production and water pollution attenuation.

11.
Sci Total Environ ; 693: 133620, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31635003

RESUMO

This paper focuses on the removal of tetracycline from polluted water by chitosan-olive pomace adsorbing films. More specifically, both raw olive solid wastes (olive pomace) and the olive solid wastes/chitosan composite were compared and used for this purpose. Adsorption capacities values of 16 mg × g-1 and 1.6 mg × g-1 were obtained for the two adsorbents respectively. However, chitosan/olive pomace is proposed as suitable for environmental applications avoiding the dispersion of the pomace blocked inside the chitosan film. To detail the adsorption process, the effect of several experimental parameters such as the pH values, ionic strength, amount of adsorbent and pollutant and temperature values was investigated. The results showed that the adsorption process improved increasing the pH values, with a maximum at pH 8, and it was negatively affected by the presence of salts that retarded the adsorption. Indeed, the desorption of tetracycline was obtained in a MgCl2 2 M solution. So, a low-cost and cleaner approach, fundamental for the pollutant recovery and for an adsorbent safe reuse, for several cycles of adsorption/desorption, transforming a waste in resource is presented. The kinetics, isotherms models of adsorption and the thermodynamic parameters (ΔG°, ΔH° and ΔS°) were also evaluated observing that the physisorption of the pollutant occurred with and an endothermic character (ΔH°â€¯> 0) with ΔG°â€¯< 0 and ΔS°â€¯> 0. The use of Advanced Oxidation Processes was proposed as possible alternative to the tetracycline recovery, obtaining its degradation after the desorption. With the present paper, the alternative reuse of olive pomace is reported avoiding its disposal in the environment claiming its potential in the removal/recover of emerging contaminants from water.


Assuntos
Tetraciclina/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Quitosana , Resíduos Industriais , Cinética , Olea , Tetraciclina/análise , Termodinâmica , Poluentes Químicos da Água/análise , Poluição da Água , Purificação da Água/métodos
12.
Water Sci Technol ; 80(4): 620-633, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31661441

RESUMO

The treatment of toxic and difficult-to-degrade phenolic compounds has become a key issue in the coking, pharmaceutical, and chemical industries. Considering the polymerization and oxidation of phenolic compounds in supercritical water partial oxidation/supercritical water oxidation (SCWPO/SCWO), the present study reviewed the removal efficiency and reaction pathway of phenolic compounds and phenolic waste/wastewater under different reaction conditions. Temperature is the dominant factor affecting the SCWO reaction. When the oxidizing ability is insufficient, the organics polymerize to form phenolic compounds. The gradual increase of oxidant equivalent causes the intermediate product to gradually oxidize to CO2 and H2O completely. Finally, the free radical reaction mechanism is considered to be a typical SCWO reaction mechanism.


Assuntos
Purificação da Água , Água , Oxirredução , Fenóis , Polimerização
13.
J Water Health ; 17(5): 683-690, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638020

RESUMO

The presence of disinfection by-products (DBPs) increases the mutagenicity of water and may pose adverse health effects. Gut microbiota exerts a fundamental role on host physiology, and how extrinsic perturbations influence its composition has been increasingly examined. However, the effect of DBPs on gut microbiota is still poorly understood. In the present study, adult zebrafish were exposed to different concentrations of dichloroacetamide (DCAcAm, an emerging nitrogenous DBP) for 30 days. Sequencing of 16S rRNA amplicons revealed a significant change in the richness and diversity of microbiota in the gut of DCAcAm-exposed zebrafish. At the phylum level, the abundance of Proteobacteria decreased and the abundance of Fusobacteria and Firmicutes increased significantly in the gut after exposure to 100 and 500 µg/L DCAcAm. At the genus level, the abundances of several bacteria which are considered pathogens or opportunistic pathogens in fish and closely related to fish metabolism, disease and inflammation (Aeromonas, Stenotrophomonas, Bacteroides and Ralstonia) increased in the DCAcAm-treated groups. Our results reveal that DBPs in drinking water potentially affect gut microbiota composition, which may contribute to the toxicity assessment of DBPs in future and provide new insight into the complex interactions between the DBPs in drinking water and host health.


Assuntos
Acetamidas/toxicidade , Desinfetantes/toxicidade , Microbioma Gastrointestinal , Purificação da Água , Peixe-Zebra/microbiologia , Animais , Desinfecção , Água Potável/química , RNA Ribossômico 16S
14.
J Water Health ; 17(5): 701-716, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638022

RESUMO

The variability of fecal microorganisms and wastewater micropollutants (WWMPs) loads in relation to influent flow rates was evaluated for a water resource recovery facility (WRRF) in support of a vulnerability assessment of a drinking water source. Incomplete treatment and bypass discharges often occur following intense precipitation events that represent conditions that deviate from normal operation. Parasites, fecal indicator bacteria, and WWMPs concentrations and flow rate were measured at the WRRF influent and effluent during dry and wet weather periods. Influent concentrations were measured to characterize potential bypass concentrations that occur during wet weather. Maximum influent Giardia and C. perfringens loads and maximum effluent Escherichia coli and C. perfringens loads were observed during wet weather. Influent median loads of Cryptosporidium and Giardia were 6.8 log oocysts/day and 7.9 log cysts/day per 1,000 people. Effluent median loads were 3.9 log oocysts/day and 6.3 log cysts/day per 1,000 people. High loads of microbial contaminants can occur during WRRF bypasses following wet weather and increase with increasing flow rates; thus, short-term infrequent events such as bypasses should be considered in vulnerability assessments of drinking water sources in addition to the increased effluent loads during normal operation following wet weather.


Assuntos
Eliminação de Resíduos Líquidos , Águas Residuárias/química , Purificação da Água , Animais , Bactérias , Cryptosporidium , Giardia , Parasitos , Águas Residuárias/microbiologia , Águas Residuárias/parasitologia , Recursos Hídricos
15.
J Water Health ; 17(5): 749-761, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638026

RESUMO

Riparian communities in the Amazon suffer from water-borne diseases due to the lack of adequate water treatment capabilities. Therefore, small local water treatment plants are necessary, but the selection of treatment procedures depends largely on the physico-chemical characteristics of the water. The aim of the present research was to evaluate the physico-chemical characteristics of the water in the Amazon River and its tributaries, in order to determine customized processes for water treatment. Data from 54 fluviometric monitoring stations were organized and used to construct distribution maps. The parameters such as pH, electrical conductivity, and the concentration of suspended matter, turbidity and flow rates were evaluated. Results showed that pH was very acidic (4-5) in the northwestern portion of the region while conductivity was quite low in the entire Amazonian region (<140 µS cm-1). Both parameters were strongly influenced by geological settings and sources of organic matter. Suspended matter and turbidity were affected by weathering processes. It was concluded that considering the acidity of the waters, mechanical procedures like filtration or slow settling should be applied to remove suspended matter rather than chemical procedures. For disinfection, instead of chemicals, solar energy should be applied.


Assuntos
Água Potável , Purificação da Água/métodos , Brasil , Condutividade Elétrica , Monitoramento Ambiental , Rios , Poluentes Químicos da Água/análise , Qualidade da Água
16.
J Water Health ; 17(5): 777-787, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638028

RESUMO

Naegleria fowleri causes the usually fatal disease primary amebic meningoencephalitis (PAM), typically in people who have been swimming in warm, untreated freshwater. Recently, some cases in the United States were associated with exposure to treated drinking water. In 2013, a case of PAM was reported for the first time in association with the exposure to water from a US treated drinking water system colonized with culturable N. fowleri. This system and another were found to have multiple areas with undetectable disinfectant residual levels. In response, the water distribution systems were temporarily converted from chloramine disinfection to chlorine to inactivate N. fowleri and reduced biofilm in the distribution systems. Once >1.0 mg/L free chlorine residual was attained in all systems for 60 days, water testing was performed; N. fowleri was not detected in water samples after the chlorine conversion. This investigation highlights the importance of maintaining adequate residual disinfectant levels in drinking water distribution systems. Water distribution system managers should be knowledgeable about the ecology of their systems, understand potential water quality changes when water temperatures increase, and work to eliminate areas in which biofilm growth may be problematic and affect water quality.


Assuntos
Infecções Protozoárias do Sistema Nervoso Central , Água Potável/parasitologia , Naegleria fowleri , Purificação da Água/métodos , Desinfetantes , Humanos , Louisiana , Estados Unidos
17.
J Water Health ; 17(5): 801-812, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638030

RESUMO

Well water around the world can be contaminated with arsenic, a naturally occurring geological element that has been associated with myriad adverse health effects. Persons obtaining their drinking water from private wells are often responsible for well testing and water treatment. High levels of arsenic have been reported in well water-supplied areas of the United States. We quantified - in cases and dollars - the potential burden of disease associated with the ingestion of arsenic through private well drinking water supplies in the United States. To estimate cancer and cardiovascular disease burden, we developed a Monte Carlo model integrating three input streams: (1) regional concentrations of arsenic in drinking water wells across the United States; (2) dose-response relationships in the form of cancer slope factors and hazard ratios; and (3) economic cost estimates developed for morbidity endpoints using 'cost-of-illness' methods and for mortality using 'value per statistical life' estimates. Exposure to arsenic in drinking water from U.S. domestic wells is modeled to contribute 500 annual premature deaths from ischemic heart disease and 1,000 annual cancer cases (half of them fatal), monetized at $10.9 billion (2017 USD) annually. These considerable public health burden estimates can be compared with the burdens of other priority public health issues to assist in decision-making.


Assuntos
Arsênico/análise , Efeitos Psicossociais da Doença , Água Potável/química , Poluentes Químicos da Água/análise , Purificação da Água , Poços de Água , Estados Unidos , Abastecimento de Água
18.
Wei Sheng Yan Jiu ; 48(5): 733-738, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31601313

RESUMO

OBJECTIVE: To understand the fluoride index of drinking water quality and its trend in rural areas of Shaanxi Province since 2008, to evaluate the effect of water improvement on reducing fluoride. METHODS: In 2008-2018, rural drinking water monitoring points were set up in the jurisdiction of the agriculture-related counties( districts) in Shaanxi Province. Water samples were collected in the April-June dry seasons and July-September wet seasons, and tested according to the Standard Test Method for Drinking Water( GB/T 5750-2006). Collected and sorted water quality monitoring information through the National Drinking Water Quality Monitoring Information System, according to the Sanitary Standards for Drinking Water( GB 5749-2006), the comparison between groups and linear trend analysis were carried out according to different annual, water period, water source type, water supply mode and region. RESULTS: From 2008 to 2018, the overall compliance rate of fluoride in rural drinking water in Shaanxi Province was 93. 37%, the concentration of fluoride in water was in the range of0. 001-9. 880 mg/L, the median was 0. 370 mg/L, and the cumulative coverage of water quality fluoride exceeded the standard project was 3. 669 million. The difference of fluoride compliance rate in different years was statistically significant( χ~2= 120. 962, P<0. 001), and the fluoride compliance rate increased with the increase of the year( χ~2= 9. 241, P =0. 002), the fluoride compliance rate of surface water was higher than that of groundwater( χ~2= 1188. 563, P < 0. 001), there was a statistically significant difference in the compliance rate of fluoride in different water treatment processes in centralized water supply projects( χ~2= 2931. 231, P < 0. 001), the highest rate of fluoride in conventional treatment was 96. 63%( P < 0. 001), and the lowest disinfection rate was 84. 78%( P <0. 001). The distribution of drinking water sources in rural areas of Guanzhong and Northern Shaanxi was mainly groundwater, accounting for 88. 12% and 92. 25%, respectively, while Southern Shaanxi was dominated by surface water, accounting for69. 99%. There were significant differences in the fluoride compliance rates in Guanzhong region, Northern Shaanxi and Southern Shaanxi( χ~2= 1919. 335, P < 0. 001). Among them, the highest in Southern Shaanxi was 99. 84%( P < 0. 001), and the lowest in Northern Shaanxi was 89. 33%( P < 0. 001)( χ~2 SouthernShaanxi, Guanzhong= 1755. 724, χ~2 Southern Shaanxi, Northern Shaanxi= 2033. 8, χ~2 Northern Shaanxi, Guanzhong= 27. 535, P < 0. 001). The overall compliance rate of fluoride in water-reducing projects was 73. 80%, which cannot prove the trend of the overall compliance rate of fluoride in water-reducing projects with the year( χ~2= 3. 168, P = 0. 075). CONCLUSION: While achieving high result in the prevention and control of high fluorine water in Shaanxi Province, it is necessary to continue to implement effective measures to reduce fluorine content in rural drinking water, and to ensure the safety of drinking water from the aspects of water supply and treatment technology.


Assuntos
Água Potável/química , Fluoretos/análise , Purificação da Água , Água Subterrânea/química , Humanos , Abastecimento de Água
19.
Wei Sheng Yan Jiu ; 48(5): 739-744, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31601314

RESUMO

OBJECTIVE: To understand the toxicological indexes of rural drinking water quality in 2016-2018 in Shaanxi Province. METHODS: From 2016 to2018, rural drinking water monitoring points were set up in all( 102) agriculture-related counties( districts) in Shaanxi Province. Each township selected 1-2 rural water supply systems for terminal water supply and terminal water and waste water for distributed water supply as monitoring points. A total of 18 284 monitoring points were set. Water samples were collected during the dry season from April to June and from July to September, according to the Standard Test Method for Drinking Water( GB/T 5750. 5-2006, GB/T5750. 6-2006, GB/T 5750. 8-2006). Carried out experimental analysis and collected water quality monitoring information through the "National Drinking Water Quality Monitoring Information System ". Experimental analysis according to the Standard Test Method for Drinking Water( GB/T 5750. 5-2006, GB/T 5750. 6-2006, GB/T5750. 8-2006); 11 toxicological indicators of the routine indicators were analyzed and evaluated according to the Standard of Drinking Water Hygiene( GB 5749-2006). RESULTS: From 2016 to 2018, the overall compliance rate of drinking water toxicology indicators in rural areas of Shaanxi Province was 81. 02%. The top four indicators exceeding the standard were fluoride( 9. 74%), nitrate nitrogen( 6. 09%) and hexavalent chromium. ( 4. 50%) and arsenic( 1. 44%), the other indicators exceeding the standard exceeds the range of 0. 01%-0. 32%. The difference of water quality compliance rates of cadmium, selenium, cyanide, fluoride and nitrate nitrogen in different years was statistically significant( P<0. 05), and the compliance rate of selenium, cyanide, fluoride and nitrate nitrogen increased with the year. Increasing trend( P<0. 05). The compliance rate of cadmium and selenium in the wet season was higher than that in the dry season, and the compliance rate of nitrate nitrogen in the dry season was higher than that in the wet season, the difference was statistically significant( P<0. 05). The compliance rate of arsenic, cadmium, hexavalent chromium, lead, selenium, fluoride and nitrate nitrogen in surface water were higher than that of groundwater( P < 0. 05). There was a statistically significant difference in the overall compliance rate of water toxicology between different water supply method in centralized water supply projects( P < 0. 001). The highest standard rate of water quality was observed in conventional water treatment, followed by sedimentation and filtration. There were 10, 10 and 4 types of over-standard indicators in Guanzhong, northern Shaanxi and southern Shaanxi, and the regional differences of 7 indicators including arsenic, cadmium, hexavalent chromium, lead, selenium, fluoride and nitrate nitrogen had statistics significance( P<0. 05). CONCLUSION: The overall compliance rate of toxicological indicators of drinking water in rural areas of Shaanxi Province is low, fluoride, nitrate nitrogen, hexavalent chromium and arsenic are serious and have obvious regional characteristics. In the future, we should focus on the excessive toxicological indicators, and ensure the safety and hygiene of drinking water from the aspects of water supply and treatment technology.


Assuntos
Água Potável/química , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Arsênico/análise , Água Subterrânea/química , Humanos , Qualidade da Água , Abastecimento de Água
20.
Water Sci Technol ; 80(3): 507-516, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31596262

RESUMO

Adsorption characteristics of high-silica zeolites (HSZSM-5) for two selected sulfonamide antibiotics (SAs) (sulfamethoxazole and sulfadiazine) were investigated. The SAs were almost completely (>90%) removed from the water by HSZSM-5. Adsorption followed second-order kinetics with liquid-film diffusion as the dominant mechanism. SA adsorption capacity on high-silica zeolites was examined in terms of pH, temperature, and the presence of natural organic matter (NOM). HSZSM-5 had better adsorption performance in acidic conditions, and the apparent distribution coefficient indicated that SA0 species were the major contribution to the overall adsorption at pH of 2-10. Adsorption of SAs on HSZSM-5 was a spontaneous and exothermic physisorption process. SA removal by HSZSM-5 was a mixed mechanism through ion-exchange and hydrophobic interaction. HSZSM-5 has potential application prospects in removing SAs from wastewater.


Assuntos
Antibacterianos/análise , Sulfonamidas/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Cinética , Dióxido de Silício
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA