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1.
Environ Monit Assess ; 193(6): 319, 2021 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-33942168

RESUMEN

A rational water quality assessment program directly affects a success of a national socio-economic development strategy. This study was aimed to evaluate and classify surface water quality in Dong Thap province, Vietnam, using set pair analysis (SPA) and national water quality index (WQI_VN) methods. The water quality data was collected at 58 locations in 2019 by the Department of Natural Resources and Environment of Dong Thap province. Sixteen variables including temperature (°C), pH, turbidity (NTU), dissolved oxygen (DO, mg/L), biological oxygen demand (BOD, mg/L), chemical oxygen demand (COD, mg/L), total suspended solids (TSS, mg/L), ammonia (N-NH4+, mg/L), nitrite (N-NO2-), nitrate (N-NO3-, mg/L), total nitrogen (TN, mg/L), orthophosphate (P-PO43-, mg/L), chloride (Cl-, mg/L), sulfate (SO42-, mg/L), coliform (MPN/100 mL), and Escherichia coli (MPN/100 mL) were monitored four times a year (58 water samples × 16 parameters × 4 monitoring times). The findings presented that TSS, BOD, COD, N-NH4+, N-NO2-, P-PO43-, coliform, and E. coli were the main constraints on water quality. The results of the entropy weight calculation indicated that deteriorated water quality was in the order of microbiological > nutrients > organic matters. Surface water quality was evaluated at medium (level III) and poor (level IV) by SPA and WQI_VN, respectively; however, the combination of SPA and entropy weight was considered more efficient in this classification and a positive spatial autocorrelation was also found through Moran's I. The spatial distribution of water quality based on SPA classification revealed that better water quality was found in the inner parts of the study area. Due to its ease and effectiveness, set pair analysis should be considered for inclusion in the water quality assessment program of Vietnam.


Asunto(s)
Ríos , Calidad del Agua , Grupo de Ascendencia Continental Asiática , Monitoreo del Ambiente , Escherichia coli , Humanos , Vietnam
2.
Mar Pollut Bull ; 166: 112231, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33798816

RESUMEN

Long-term assessments are needed to identify water quality trends and their socio-environmental drivers for coastal management and watershed restoration. This study provides the first long-term assessment of fecal bacterial pollution in the northwestern Gulf of Mexico using enterococci data spanning the Texas coast from 2009 to 2020. The data were representative of 66 beaches, 169 stations, and over 75,000 samples. Findings demonstrate that 22 beaches are 'hotspots' of pollution and experienced enterococci levels that frequently exceeded the USEPA beach action value. Further, enterococci were correlated with time, population size, and sea level. Weak correlations detected in some counties highlight the multifactorial nature of water quality; additional factors are likely influencing enterococci levels. The correlation with sea level is concerning, as counties vulnerable to sea level rise frequently reported enterococci concentrations exceeding the beach action value. In consideration of sea level rise predictions, targeted studies are needed to pinpoint drivers of fecal pollution.


Asunto(s)
Playas , Calidad del Agua , Monitoreo del Ambiente , Heces , Golfo de México , Elevación del Nivel del Mar , Texas , Microbiología del Agua , Contaminación del Agua/análisis
3.
J Environ Manage ; 289: 112459, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33799066

RESUMEN

Water purification is one of the most essential services provided by wetlands. A lot of concerns regarding wetlands subjected to climate change relate to their susceptibility to hydrological change and the increase in temperature as a result of global warming. A warmer condition may accelerate the rate of decomposition and release of nutrients, which can be exported downstream and cause serious ecological challenges; e.g., eutrophication and acidification. The aim of this study is to investigate the effect of climate change on water quality in peatland and constructed wetland ecosystems subject to water level management. For this purpose, the authors simulated the current climate scenario base on the database from Malmö station (Scania, Sweden) for 2016 and 2017 as well as the future climate scenarios for the last 30 years of the century based on the Representative Concentration Pathway (RCP) and different regional climate models (RCM) for a region wider than Scania County. For future climate change, the authors simulated low (RCP 2.6), moderate (RCP 4.5) and extreme (RCP 8.5) climate scenarios. All simulations were conducted within climate chambers for experimental peatland and constructed wetland mesocosms. Our results demonstrate that the effect of climate scenario is significantly different for peatlands and constructed wetlands (interactive effect) for the combined chemical variables. The warmest climate scenario RCP 8.5 is linked to a higher water purification function for constructed wetlands, but to a lower water purification function and a subsequent deterioration of peatland water qualities, even if subjected to water level management. The explanation for the different response of constructed wetlands and peatlands to climate change could be due to the fact that the substrate in the constructed wetland mesocosms and peatlands was different in terms of the organic matter quality and quantity. The utilization of nutrients by the plants and microbial community readily exceed the mineralization under a limited nutrient content (as we had in constructed wetland) when the temperature rises. However, concerning the extreme scenario RCP 8.5, the peatlands have shown a tendency to have reverse processes.


Asunto(s)
Ecosistema , Humedales , Cambio Climático , Suecia , Calidad del Agua
4.
J Environ Manage ; 289: 112522, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33848878

RESUMEN

COVID-19 pandemic has caused profound impacts on human life and the environment including freshwater ecosystems globally. Despite the various impacts, the pandemic has improved the quality of the environment and thereby creating an opportunity to restore the degraded ecosystems. This study presents the imprints of COVID-19 lockdown on the surface water quality and chemical characteristics of the urban-based Bagmati River Basin (BRB), Nepal. A total of 50 water samples were collected from 25 sites of BRB during the monsoon season, in 2019 and 2020. The water temperature, pH, electrical conductivity, total dissolved solids, dissolved oxygen (DO), and turbidity were measured in-situ, while the major ions, total hardness, biological oxygen demand (BOD), and chemical oxygen demand (COD) were analyzed in the laboratory. The results revealed neutral to mildly alkaline waters with relatively moderate mineralization and dissolved chemical constituents in the BRB. The average ionic abundance followed the order of Ca2+ > Na+ > Mg2+ > K+ > NH4+ for cations and HCO3-> Cl- > SO42- > NO3- > PO43- for anions. Comparing to the pre-lockdown, the level of DO was increased by 1.5 times, whereas the BOD and COD were decreased by 1.5 and 1.9 times, respectively during the post-lockdown indicating the improvement of the quality water which was also supported by the results of multivariate statistical analyses. This study confirms that the remarkable recovery of degraded aquatic ecosystems is possible with limiting anthropic activities.


Asunto(s)
Contaminantes Químicos del Agua , Control de Enfermedades Transmisibles , Ecosistema , Monitoreo del Ambiente , Humanos , Nepal , Pandemias , Ríos , Contaminantes Químicos del Agua/análisis , Calidad del Agua
5.
J Environ Manage ; 289: 112555, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33848882

RESUMEN

The regulatory management of river water quality requires measurements of phosphorus that are operationally viable and meaningful in terms of insight into its effects. This need is a particular concern in globally rare and ecologically sensitive chalk streams. P data pertaining to rivers are commonly limited to soluble reactive P; other fractions of P may be of concern but are not routinely monitored. This study seeks to establish the nature and extent of non-regulated forms of P in UK chalk streams. Whilst soluble reactive P in two southern English chalk streams was found to comprise the majority of reactive P in surface waters in the majority of samples, 15-20% of the total reactive P was within other size fractions greater than 0.22 µm. The contribution of reactive P to the total P was highly variable. We conclude that, with some adjustments, the established method of regulatory monitoring of P in UK rivers is viable and valuable. In cases where the levels of reactive P are not consistent with ecological status and/or expected outcomes of programmes of measures, we recommend that targeted analysis of non-regulated forms of P is undertaken as a means to guide and focus management interventions.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Carbonato de Calcio , Monitoreo del Ambiente , Fósforo/análisis , Reino Unido , Contaminantes Químicos del Agua/análisis , Calidad del Agua
6.
Water Res ; 197: 117085, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33862394

RESUMEN

Fluid flow through a bed of solid particles is an important process that occurs in full-scale water treatment operations. The Carman-Kozeny model remains highly popular for estimating the resistance across the bed. It is common practice to use particle shape factors in fixed bed state to match the predicted drag coefficient with experimentally obtained drag coefficients. In fluidised state, however, where the same particles are considered, this particle shape factor is usually simply omitted from the model without providing appropriate reasoning. In this research, it is shown that a shape factor is not a constant particle property but is dependent on the fluid properties as well. This dynamic shape factor for irregularly shaped grains increases from approximately 0.6 to 1.0 in fluidised state. We found that unstable packed beds in moderate up-flow conditions are pseudo-fixed and in a setting state. This results in a decreasing bed voidage and simultaneously in a decreasing drag coefficient, which seems quite contradictory. This can be explained by the collapse of local channels in the bed, leading to a more uniform flow distribution through the bed and improving the available surface for flow-through. Our experimental measurements show that the drag coefficient decreases considerably in the laminar and transition regions. This is most likely caused by particle orientation, realignment and rearrangement in particles' packing position. A thorough hydraulic analysis shows that up-flow filtration in rapid sand filters under backwash conditions causes the particle bed to collapse almost imperceptibly. In addition, an improved expression of the drag coefficient demonstrated that the Carman-Kozeny model constant, however often assumed to be constant, is in fact not constant for increasing flow rates. Furthermore, we propose a new pseudo-3D image analysis for particles with an irregular shape. In this way, we can explain the successful method using optimisation of the extended terminal sub-fluidisation wash (ETSW) filter backwashing procedure, in which turbidity and peaks in the number of particles are reduced with a positive effect on water quality.


Asunto(s)
Arena , Purificación del Agua , Filtración , Calidad del Agua
7.
Environ Monit Assess ; 193(5): 306, 2021 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-33905038

RESUMEN

The El Moghra area is located in northwestern Egypt in the Western Desert. It is classified as the first priority of the national project to reclaim 1.50 million feddan of Egypt's desert lands. Groundwater quality assessment of the El Moghra aquifer is essential because irrigation water requirements in the El Moghra area depend solely on groundwater. A geochemistry analysis was conducted for 230,000 feddans from forty-six groundwater samples collected during the drilling process of deep wells in year 2018 and 2019. Our study's main objective is to determine whether the groundwater in the El Moghra aquifer is suitable for irrigation use. ArcGIS was used to prepare the geospatial distribution maps of major elements. Hydrochemical characteristics and groundwater types were identified from descriptive analyses of groundwater samples. Multivariate statistical analysis was run using SPSS; correlation coefficients were first determined; then, a correlation matrix was generated. Principal component analysis was performed and a covariance matrix with varimax rotation was produced. Results revealed the alkalinity and the high salinity of groundwater in the project study area. Most of the samples had a total hardness greater than 300 mg/l. Sodium chloride (Na-Cl) is the dominant type for groundwater samples. The mechanism controlling groundwater chemistry depends on rock weathering. Principal component analysis results showed that two eigenvectors among ten have a 72.86% contribution to the cumulative variance. The higher TDS values (14,008 mg/l) confirm the ions release when the upward groundwater flow from the lower Nubian Sandstone aquifer system to the upper quaternary aquifer occurs. Additionally, the geospatial maps of ion distribution showed that the frequent release of minerals happens in the northwestern part of the project study area: the eastern Qattara Depression. A perfect correlation between sodium and chloride distributions was obtained, and it is identical to the electrical conductivity distribution as well. Our study recommends very salt-tolerant crops as canola, barley, quinoa, and jojoba to be planted in the project area. Drought-tolerant crops as Barbary fig and Jatropha are also recommended. Applying irrigation water frequently with short intervals between irrigations to avoid soil drying and surface clusters' formation, as well as enhance leeching of salts away from the root systems, is essential.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Egipto , Monitoreo del Ambiente , Sistemas de Información Geográfica , Salinidad , Contaminantes Químicos del Agua/análisis , Calidad del Agua
8.
Environ Monit Assess ; 193(5): 315, 2021 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-33929607

RESUMEN

The quality and potability of waters of the Tysmienica River Basin were determined in 2017 at eight measuring stations. The paper presents analyses of the physical and chemical parameters of surface waters of the basin. With regard to suspended solids, pH value, electric conductivity, sulphates, ammonia, chlorides and phosphate, the water was classified as having a very good ecological status. In the case of Kjeldahl nitrogen, the waters were classified as having a good ecological status. In the case of the remaining parameters, i.e. BOD, DO, TOC and COD, the status varied among stations. The values of all the physical and chemical parameters complied with the values for undisturbed conditions. Only ammonia and COD showed significant differences among stations. The WPI values for each measuring point ranged from 0.90 to 1.56, what corresponds to the descriptive indicators of moderately polluted water. The high concentrations of COD and TOC indicate that high-performance treatment processes (category A3) must be used to ensure that the water is suitable for drinking.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Polonia , Contaminantes Químicos del Agua/análisis , Contaminación del Agua , Calidad del Agua
9.
Environ Monit Assess ; 193(5): 280, 2021 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-33864518

RESUMEN

Biomonitoring is a significant method for evaluating aquatic life forms and their environments. The longer the process continues, the results of it become more precise. Benthic macroinvertebrates' exposure to changes in environmental conditions makes them an important part of any biomonitoring program. This paper reviews a long-term water quality of the Buyuk Menderes River Basin which is the biggest river basin spread across the western Anatolia (Turkey). The study area was divided into three regions (Usak, Aydin, Denizli), primarily considering the provincial borders in the basin. A total of 40 sampling sites from the main river and its tributaries were selected. The prominent agricultural and industrial pollutants (textile, tannery and sugar factories) from each region have been taken into account. The most common and current biotic indices (BMWP Spanish version, ASPT, RBPIII, MMIF, EPT%, Diversity and Evenness) based on the pollution tolerance of benthic macroinvertebrates have been used to track water quality changes. The relationships between environmental variables (sO2, dO2, water temp., salinity, flow, TDS, Cond, pH, NO3-N, NO2-N, PO4-P, Fe+3, NH4-N) and bioindicators have been revealed by using multivariate analyses (NMDS, CCA). The region-based variations in water quality were compared with the Kruskal-Wallis test. The one-way variance analysis test (ANOVA) was used for the contrast between the biotic indices. Significant differences (p < 0.05) were found among the regions in terms of Shannon-Wiener, Evenness, BMWP and MMIF indices. Regions were separated according to pollution sources, and the impact of provinces on water quality may vary according to their industry types. It has been observed that pollutants can spread across a basin for very long distances and reinstatement of the environmental conditions may require long periods.


Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Animales , Monitoreo del Ambiente , Invertebrados , Ríos , Turquia , Contaminantes Químicos del Agua/análisis , Calidad del Agua
10.
J Environ Manage ; 288: 112444, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33823450

RESUMEN

Effective treatment options are needed for the management of aquatic invasive species. An herbicide treatment was used to control an invasive aquatic plant, yellow floating heart (Nymphoides peltata) in a 3350-acre drinking water reservoir. The purpose of this research was to document the success of the treatment in an individual cove of the reservoir using in-situ sampling and reservoir-wide using remotely sensed Sentinel-2 satellite imagery. We also determined if the dying vegetation negatively impacted biological oxygen demand and dissolved oxygen concentrations in the cove. The aquatic herbicide ProcellaCOR™ (active ingredient = florpyrauxifen-benzyl) was used to treat a 55-acre infestation of YFH at a rate of 3 Prescription Dose Units (PDU)/ac-ft by a certified applicator in July 2019. Total surface coverage of yellow floating heart in the reservoir was reduced by more than 90% within 15 days after the treatment, and to less than 3.0 acres within 50 days after the treatment. No blooming flowers were observed after treatment and the surface coverage was close to 0% within 17 days after treatment in the cove. The effect of the herbicide treatment also appeared to carry over into the following growing season as the total surface coverage of yellow floating heart in the reservoir was less than 8 acres one year after the treatment in July 2020. The herbicide treatment resulted in short term increases in biological oxygen demand and decreases in dissolved oxygen at some sites in the cove within 3-10 days after the treatment. Dissolved oxygen then increased and concentrations were greater 42 days after treatment than they were before the treatment. Our results show that ProcellaCOR™ has the potential to control yellow floating heart infestations with relatively short-term negative impacts on dissolved oxygen concentrations. We also show that Sentinel-2 satellite imagery can be used to monitor the success of herbicide applications over large spatial and temporal scales that would not be possible from ground based monitoring alone.


Asunto(s)
Agua Potable , Herbicidas , Análisis de la Demanda Biológica de Oxígeno , Monitoreo del Ambiente , Calidad del Agua
11.
Ying Yong Sheng Tai Xue Bao ; 32(4): 1471-1478, 2021 Apr.
Artículo en Chino | MEDLINE | ID: mdl-33899416

RESUMEN

Water quality under tourism disturbance was simulated through controlling the water intake of the ecological breeding ponds of Chinese giant salamander (Andrias davidianus, CGS). Both the reproductive behavior (oviposition and parental care) and capacity (relative egg production, fertilizing rate of eggs, and hatching rate of fertilized eggs) of CGS were examined using a real-time infrared digital monitoring system. The relationships among reproductive behavior, capacity, and the corresponding parameters of water quality were analyzed, to understand how water quality under tourism disturbance would affect the reproductive behavior and capacity of CGS. The examined oviposition behavior and capacity of CGS showed no variation in general, but the parental care behavior such as tail fanning and agitation time of the male CGS were prolonged significantly in the groups under tourism disturbance. Such prolonged behaviors would help increase the content of dissolved oxygen (DO) to meet the high demands of DO during embryonic development of CGS. In addition, the overall hatching time of fertilized eggs was increased significantly under disturbance conditions when it compared with the control, which would ensure the overall hatching rate among these comparative groups unaffected. In summary, the prolongations of some reproductive behavior (tail fanning and agitation of the male CGS and the development time of fertilized egg) would be a kind of positive actions of CGS in response to the changes of water quality resulted from tourism disturbance.


Asunto(s)
Conducta Reproductiva , Calidad del Agua , Animales , Femenino , Masculino , Turismo , Urodelos
12.
Cad Saude Publica ; 37(3): e00084520, 2021.
Artículo en Portugués | MEDLINE | ID: mdl-33852662

RESUMEN

The study presents an assessment of the health and social impacts from the implementation of water supply systems in riverine communities in the Middle Solimões region, Amazonas State, Brazil. Data were collected in 21 rural communities, 19 of which received the water access technology experimentally in the last 14 years. For comparison, three rural communities that had not received the technology participated in the study. A quantitative/qualitative methodology was used with the following techniques: focus groups, semi-structured interviews, questionnaires, parasitological tests, and water quality analysis. Even without a reduction in the prevalence of parasite infections, the systems showed impacts on comfort, privacy, and reduction in the time spent on household chores such as fetching water or having to wash clothes and pots and pans outdoors and far from home. The impacts point to an improvement in living conditions from the perspective of wellbeing.


Asunto(s)
Calidad del Agua , Agua , Brasil , Humanos , Población Rural , Tecnología
13.
Environ Monit Assess ; 193(5): 289, 2021 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-33886032

RESUMEN

In Brazil, wastewater treatment coverage is low. Even when treatment is carried out, many municipalities cannot achieve adequate levels of contaminant removal, and the usual practice of releasing raw or treated domestic effluent into water bodies remains. Thus, this pollution source puts pressure on water resources, compromising downstream uses of the disposal. This study has two aims: (1) to evaluate the performance of sewage treatment plants and (2) to determine the impact of discharging treated effluent on the water quality of receiving water bodies located within an urbanized area in the Velhas River basin, Minas Gerais State, Brazil. Monitoring data from raw wastewater were compared with typical ranges reported in literature, and effluent concentrations were compared between plants. The monitoring data of the receiving water bodies collected at points upstream and downstream of each disposal were statistically compared. Different performances between the systems and significant alterations in the receiving bodies resulting from the discharge of the treated effluents were found.


Asunto(s)
Contaminantes Químicos del Agua , Calidad del Agua , Brasil , Ciudades , Monitoreo del Ambiente , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas Residuales , Contaminantes Químicos del Agua/análisis
14.
Environ Monit Assess ; 193(5): 247, 2021 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-33822279

RESUMEN

The study presents the characterization of the water quality of the Corumbá IV reservoir in the State of Goiás, in the Brazilian Cerrado biome, based on data from the operation period between 2007 and 2017. Few are known about the temporal and spatial variations in the water quality of the reservoir. Up to now, the water quality has been analyzed only from the point of view of compliance with the limits required by Brazilian environmental legislation. Therefore, the integrated analysis of water quality parameters and water body dynamics may bring important information to support decision-making in reservoir management. An exploratory analysis of the limnological data series provided by the company in charge of the hydroelectric plant was then carried out. Univariate and multivariate statistical techniques were applied to analyze the data period from 2007 to 2017. The results identify four distinct limnological phases representing the transition of the environment. The first phase (2007 to 2009) characterized by the decomposition of the flooded vegetal organic matter and subsequent phases, after 8 years (2010 to 2017), have featured the transition process from the lotic condition to the consolidation of the lentic environment. The spatial analysis of the results demonstrates that tributaries influence the water quality of the reservoir differently, probably due to the different impacts suffered in the sub-basins (e.g., sewage discharges; runoff). Although it is possible to evidence the impact of anthropic activities on water quality, the reservoir still presents characteristics of an environment with low trophic status.


Asunto(s)
Monitoreo del Ambiente , Calidad del Agua , Brasil , Ecosistema , Ríos , Análisis Espacio-Temporal
15.
Environ Monit Assess ; 193(5): 308, 2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33909164

RESUMEN

The water quality and trends in 12 tropical rivers in northeastern Brazil over a 27-year period (1990-2016; N = 39,008 samples) were evaluated. The analyzed parameters included temperature, conductivity, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), nitrogen (NH4+), total phosphorus (P), and fecal coliforms. Densely populated basins (> 1000 inhab km-2) presented lower DO values (average 3.4 mg l-1; 43% DO saturation), while those with low demographic density (< 100 inhab km-2) presented values that aligned well with the recommendations of environmental legislation (average 5.8 mg l-1; 75% DO saturation). The NH4+ and P compound concentrations were typical of water bodies affected by urban inputs. The average p values were above the allowable limit (< 0.1 mg l-1) at all stations. The NH4+ values were high at the stations showing low DO concentrations, which suggested that due to reducing conditions after NH4+ accumulation was favored in those aquatic systems. In densely populated basins, the average fecal coliform concentrations were > 40,000 MPN 100 ml-1, indicating the input of improperly treated domestic/industrial liquid wastes. For the period from 1990 to 2016, 45% of the stations (N = 19) showed a rate of DO reduction that ranged from 0.01 to 0.17 mg l-1.O2 year-1. An increase in NH4+ concentrations was observed in 33% of the stations (N = 14), with an estimated average increase rate from 0.013 to 1.8 mg l-1 NH4+ year-1. These results demonstrated that the rates of increase in anthropogenic factors were significant (p < 0.05), while the natural factors remained constant.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Brasil , Monitoreo del Ambiente , Nitrógeno/análisis , Fósforo/análisis , Contaminantes Químicos del Agua/análisis , Calidad del Agua
16.
J Water Health ; 19(2): 203-215, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33901018

RESUMEN

The rationale for this study was to assess the physicochemical and bacteriological qualities of the Vea irrigation water and resultant effects on the quality of fresh vegetables produced in the area and associated implications for consumers' health. A total of 45 water samples were collected from the reservoir and canals. Also, 16 vegetable samples comprising four samples each of tomatoes, carrots, spring onions, and cabbages were collected from four farms with installed irrigation systems fed by the Vea Dam. The irrigation water samples were analyzed for total coliform (TC) and fecal coliform (FC), Escherichia coli, pH, and turbidity, while the samples of vegetables were analyzed for TC and FC, and E. coli. The results showed that except for pH, the bacterial loads and turbidity of the sampled vegetables and irrigation water were above the standards of the WHO and the International Commission on Microbiological Specifications for Food. Comparatively, the samples of cabbage recorded the highest levels of microbial contamination. The study suggests that the water should be treated before being used for irrigation; consumers should ensure that vegetables are properly washed and cooked/treated before consumption; and periodic monitoring and assessment should be done to ensure that the adverse effects of these activities are forestalled.


Asunto(s)
Verduras , Calidad del Agua , Riego Agrícola , Escherichia coli , Contaminación de Alimentos , Jardinería , Ghana , Microbiología del Agua
17.
J Water Health ; 19(2): 306-321, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33901026

RESUMEN

The present work evaluated the surveillance of the drinking water quality information system database and correlated the findings of the microbiological analysis with the distribution of intestinal protozoa from the metropolitan region of Rio de Janeiro. From the database, we obtained 1,654 georeferenced monitoring stations that were used in the analysis. The results indicate that the minimum number of samples collected per parameter (free residual chlorine, turbidity, counts of total and fecal coliforms (Escherichia coli)) was not fulfilled, the collection of samples throughout the year was irregular and the representability of sampling points considered strategic was low (48% of municipalities). Besides, municipalities with a high prevalence for intestinal parasite protozoa were also the ones that had the highest counts for coliforms and the reverse can also be observed, indicating a transmission through contaminated drinking water. Despite the increased participation of municipalities in water surveillance actions during the studied period, it is necessary to implement managerial measures to improve the system, aiming to correct flaws and inconsistencies in the application of the water quality monitoring protocol.


Asunto(s)
Agua Potable , Calidad del Agua , Animales , Cloro/análisis , Escherichia coli , Microbiología del Agua , Abastecimiento de Agua
18.
Water Res ; 197: 117071, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33799082

RESUMEN

There are many sampling approaches available for lead (Pb) in drinking water. Selecting the best approach for its intended use is critical. The objective of this work was to compare water Pb levels collected by multiple sampling approaches from a model home plumbing system (HPS) that included an old Pb service line (LSL), as a function of daily water usage. Specifically, flushed, direct LSL, sequential profile, random daytime (RDT), first draw, and manual composite samples were compared, and daily water usage rates ranged from 1.4 to 120 gallons/day (5.3-454.2 L/day). Pb levels in water collected directly from the LSL reached equilibrium after 7-15.5 h of stagnation, and approximately 55% of the equilibrium Pb concentration was reached after 2 h. Sequential sampling accurately identified the LSL; however, the peak profile Pb concentrations were a fraction of the Pb measured directly from the LSL. Daily water usage patterns greatly impacted total Pb levels in all water sampling approaches, although manual composite and RDT samples were more sensitive to changes. Manual composite and RDT samples were equal to or greater than first draw samples throughout the study, and differences grew larger as water usage decreased.


Asunto(s)
Agua Potable , Contaminantes Químicos del Agua , Agua Potable/análisis , Plomo/análisis , Agua , Contaminantes Químicos del Agua/análisis , Calidad del Agua , Abastecimiento de Agua
19.
Water Res ; 197: 117044, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33799083

RESUMEN

To control microbial proliferation and nitrification within distribution systems, utilities practicing secondary disinfection chloramination often discontinue their ammonia feed and provide a short, free chlorine disinfection period (FClP), commonly referred to as a "chlorine burn". However, the success and practicality of this approach is often criticized because of the return to nitrification; yet, previous studies conducted in full-scale distribution systems do not contain the sampling frequency to determine how quickly nitrification can return. In this research, a total of 15 hydrants distributed across hydraulically modeled water ages were sampled for 21 sampling events over a period spanning two annual FClPs (2018 and 2019) to investigate the water quality, planktonic community, and, using a new sampling technique, established biofilm community impacts within a single, distribution system pressure zone. Hydrants measured elevated nitrite only 10 weeks after the end of the FClP and live cell counts in the bulk and scour samples statistically significantly increased within two weeks after the FClP ended and chloramine disinfection resumed, indicating limited impacts from a FClP. Furthermore, the FClP significantly increased iron concentrations during the period of free chlorine disinfection creating a consumer water quality concern. Microbial fingerprint analysis using flow cytometry revealed that beta diversity did not significantly change for sampling locations that experienced even periodic low total chlorine concentrations. Only locations that maintained high chlorine residuals throughout both chloramine and free chlorine disinfection periods demonstrated significant changes in bulk water microbial community. Even for these locations, microbial communities of the scoured biofilms remained similar over the course of the study.


Asunto(s)
Quemaduras , Desinfectantes , Agua Potable , Purificación del Agua , Biopelículas , Cloraminas/análisis , Cloro , Desinfección , Humanos , Calidad del Agua , Abastecimiento de Agua
20.
Water Res ; 197: 117105, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33845280

RESUMEN

Invasive quagga mussels (Dreissena rostriformis bugensis) are an emerging threat to the functioning and management of freshwater ecosystems. Quagga mussels were first recorded in the UK in 2014 and have subsequently established at high densities in a number of major reservoirs. Through implementing a Progressive-Change BACIPS (Before-After-Control-Impact Paired Series) analysis, we found that the following trends were observed following quagga mussel establishment: reduced diatom and cyanobacteria abundances; increased soluble reactive phosphorus and reactive silica concentrations; and reduced abundances of Aphanizomenon sp., a potentially toxic cyanobacterium. We also found reservoirs with established quagga mussel populations experienced slightly increased overall chlorophyll a concentration but no changes in turbidity or Microcystis sp. abundance, which are often considered common indicators of dreissenid invasion. Our results show that Progressive-Change BACIPS analysis is a powerful tool which can be used to interrogate industry standard long-term datasets of water quality metrics in order to identify and quantify the impacts of invasive species when the approximate timeframe of species arrival is known. We also demonstrate that quagga mussels may have had significant effects on reservoir ecosystems which, primarily through their impacts on phytoplankton communities, may have implications for reservoir management.


Asunto(s)
Bivalvos , Dreissena , Animales , Clorofila A , Ecosistema , Calidad del Agua
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