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1.
J Hazard Mater ; 421: 126714, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34325293

RESUMEN

Cryptosporidium is a critical waterborne protozoan pathogen found in water resources that have been a major cause of death and serious illnesses worldwide, costing millions of dollars annually for its detection and treatment. Over the past several decades, substantial efforts have been made towards developing techniques for the detection of Cryptosporidium. Early diagnostic techniques were established based on the existing tools in laboratories, such as microscopes. Advancements in fluorescence microscopy, immunological, and molecular techniques have led to the development of several kits for the detection of Cryptosporidium spp. However, these methods have several limitations, such as long processing times, large sample volumes, the requirement for bulky and expensive laboratory tools, and the high cost of reagents. There is an urgent need to improve these existing techniques and develop low-cost, portable and rapid detection tools for applications in the water quality industry. In this review, we compare recent advances in nanotechnology, biosensing and microfluidics that have facilitated the development of sophisticated tools for the detection of Cryptosporidium spp.Finally, we highlight the advantages and disadvantages, of these state-of-the-art detection methods compared to current analytical methodologies and discuss the need for future developments to improve such methods for detecting Cryptosporidium in the water supply chain to enable real-time and on-site monitoring in water resources and remote areas.


Asunto(s)
Criptosporidiosis , Cryptosporidium , Criptosporidiosis/diagnóstico , Cryptosporidium/genética , Humanos , Calidad del Agua , Abastecimiento de Agua
2.
J Environ Sci (China) ; 110: 48-54, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34593194

RESUMEN

Acetochlor is a widely used herbicide in agricultural production. Studies have shown that acetochlor has obvious environmental hormone effects, and long-term exposure may pose a threat to human health. To quantify the hazards of acetochlor in drinking water, a health risk assessment of acetochlor was conducted in major cities of China based on the data of acetochlor residue concentrations in drinking water. The approach of the Species Sensitivity Distributions (SSD) method is used to extrapolate from animal testing data to reflect worst case human toxicity. Results show that hazard quotients related to acetochlor residues in drinking water for different age groups range from 1.94 × 10-4 to 6.13 × 10-4, so, there are no indication of human risk. Compared to the total estimated hazard quotient from oral intake of acetochlor, the chronic exposure imputed to acetochlor residues in drinking water in China accounts for 0.4%. This paper recommends 0.02 mg/L to be the maximum acetochlor residue concentration level in drinking water and source water criteria.


Asunto(s)
Herbicidas , Calidad del Agua , Animales , Herbicidas/análisis , Herbicidas/toxicidad , Humanos , Medición de Riesgo , Toluidinas/análisis , Toluidinas/toxicidad
3.
J Environ Sci (China) ; 110: 73-83, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34593196

RESUMEN

Significant iron release from cast iron pipes in water distribution systems (WDSs), which usually occurs during the source water switch period, is a great concern of water utilities because of the potential occurrence of "red water" and customer complaints. This study developed a new method which combined in-situ water stagnation experiments with mathematical models and numerical simulations to predict the iron release caused by source water switch. In-situ water stagnation experiments were conducted to determine the total iron accumulation in nine cast iron pipes in-service in Beijing when switching the local water to treated Danjiangkou Reservior water. Results showed that the difference in the concentration increment of total iron in 24 hr (ΔCITI,24), i.e. short-term iron release, caused by source water switch was mainly dependent on the difference in the key quality parameters (pH, hardness, nitrate, Larson Ratio and dissolved oxygen (DO)) between the two source waters. The iron release rate (RFe) after switch, i.e. long-term iron release, was closely related to the pipe properties as well as the DO and total residual chlorine (TRC) concentrations. Mathematical models of ΔCITI,24 and RFe were developed to quantitatively reveal the relationship between iron release and the key quality parameters. The RFe model could successfully combine with EPANET-MSX, a numerical simulator of water quality for WDSs to extend the iron release modeling from pipe level to network level. The new method is applicable to predicting iron release during source water switch, thus facilitating water utilities to take preventive actions to avoid "red water".


Asunto(s)
Agua Potable , Hierro , Cloro , Corrosión , Calidad del Agua , Abastecimiento de Agua
4.
Environ Monit Assess ; 193(11): 712, 2021 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-34633550

RESUMEN

Groundwater quality assessment is an important measure to determine the usability of available water based on its physical, chemical, and bacteriological properties. In the present study, 10 physicochemical parameters have been considered for the groundwater quality assessment which include potential of hydrogen (pH), electrical conductivity (EC), total dissolved solids (TDS), sodium (Na+), potassium (K+), total hardness (TH), calcium (Ca2+), magnesium (Mg2+), bicarbonate (HCO3-), and chloride (Cl-). For the analysis, 21 samples for pre- and post-monsoon periods were collected from the wells/bore wells of five designated villages, Chinna Madina, Chittiyyapalem, Typuram, Rajam, and Neelakantapuram of the Butchayyapeta Mandal (sub-district) located in Visakhapatnam District, Andhra Pradesh, for the year 2017. The Bureau of Indian Standards (BIS 2012) has been used in this study to assess the suitability of the water for drinking. The water quality index (WQI) values derived by using WAI were categorized for various levels of water quality ranging from "excellent" to "unsuitable for drinking." To get the spatial distribution pattern, the WQI values of sample points were interpolated in the Arc GIS environment. The results indicated that water quality is good in the north-western parts of the current study area during pre- and post-monsoon seasons.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Contaminantes Químicos del Agua/análisis , Calidad del Agua , Abastecimiento de Agua
5.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 52(5): 729-734, 2021 Sep.
Artículo en Chino | MEDLINE | ID: mdl-34622584

RESUMEN

Along with the economic and technological development and growing demand for high-quality drinking water, direct drinking water has gained general popularity in China. However, no authoritative policy has been issued, giving a clear definition of direct drinking water and existing standards and regulations concerning direct drinking water are not definitive in nature. Existing water quality parameters are not well supported and sometimes even contradict each other. We elaborated, in this paper, the history of direct drinking water in China and systematically reviewed the existing regulations and standards related to direct drinking water. We also compared and analyzed the important microbiology, toxicology, sensory perception and general chemistry parameters in the standards. This paper is the first ever attempt at an in-depth analysis of the chaotic state of the direct drinking water industry. We have also highlighted the problems in the current standards and regulations for direct drinking water. Our study provides a basis for market regulation and the supervision and management of direct drinking water. In addition, the paper provides helpful information for laying down a definition of direct drinking water, calling for and approving of project proposals concerning the establishment of national standards for direct drinking water, and actually formulating the standards. We have made a number of suggestions: A. defining direct drinking water clearly and formulating the national standards for direct drinking water as soon as possible; B. conducting research on water quality benchmarks to provide scientific support for the formulation of the national standards for direct drinking water; C. giving more attention to the formulation of standards concerning microbiology parameters and their limits and giving consideration to the inclusion of parameters concerning viruses.


Asunto(s)
Agua Potable , Contaminantes Químicos del Agua , China , Saneamiento , Contaminantes Químicos del Agua/análisis , Calidad del Agua
6.
Sci Rep ; 11(1): 20140, 2021 10 11.
Artículo en Inglés | MEDLINE | ID: mdl-34635728

RESUMEN

The global economic activities were completely stopped during COVID-19 lockdown and continuous lockdown partially brought some positive effects for the health of the total environment. The multiple industries, cities, towns and rural people are completely depending on large tropical river Damodar (India) but in the last few decades the quality of the river water is being significantly deteriorated. The present study attempts to investigate the river water quality (RWQ) particularly for pre- lockdown, lockdown and unlock period. We considered 20 variables per sample of RWQ data and it was analyzed using novel Modified Water Quality Index (MWQI), Trophic State Index (TSI), Heavy Metal Index (HMI) and Potential Ecological Risk Index (RI). Principal component analysis (PCA) and Pearson's correlation (r) analysis are applied to determine the influencing variables and relationship among the river pollutants. The results show that during lockdown 54.54% samples were brought significantly positive changes applying MWQI. During lockdown, HMI ranged from 33.96 to 117.33 with 27.27% good water quality which shows the low ecological risk of aquatic ecosystem due to low mixing of toxic metals in the river water. Lockdown effects brought river water to oligotrophic/meso-eutrophic condition from eutrophic/hyper-eutrophic stage. Rejuvenation of river health during lockdown offers ample scope to policymakers, administrators and environmentalists for restoration of river health from huge anthropogenic stress.


Asunto(s)
COVID-19/prevención & control , Control de Enfermedades Transmisibles/normas , Ríos/química , Contaminantes Químicos del Agua/análisis , Calidad del Agua , COVID-19/epidemiología , COVID-19/transmisión , Monitoreo del Ambiente/estadística & datos numéricos , Restauración y Remediación Ambiental/estadística & datos numéricos , Humanos , Metales Pesados/análisis
7.
Sensors (Basel) ; 21(19)2021 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-34640822

RESUMEN

In this paper, a Multi-Objective Genetic Algorithm (MOGA) framework for the design of Artificial Neural Network (ANN) models is used to design 1-step-ahead prediction models of river water levels. The design procedure is a near-automatic method that, given the data at hand, can partition it into datasets and is able to determine a near-optimal model with the right topology and inputs, offering a good performance on unseen data, i.e., data not used for model design. An example using more than 11 years of water level data (593,178 samples) of the Carrión river collected at Villoldo gauge station shows that the MOGA framework can obtain low-complex models with excellent performance on unseen data, achieving an RMSE of 2.5 × 10-3, which compares favorably with results obtained by alternative design.


Asunto(s)
Redes Neurales de la Computación , Ríos , Agua , Calidad del Agua
8.
Environ Monit Assess ; 193(11): 715, 2021 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-34637024

RESUMEN

Artisanal small-scale mining has been part of Ghana's history, but recent public outcry on the devastating impacts of the phenomenon on water bodies, due to expansion in the sector, has led to clamp downs by various governments on the activity. This has called for evaluation of the water quality of the South-western Rivers System, which are small-scale mining endemic areas. Thirty-five river samples were collected in July 2018 and were analyzed for physico-chemical parameters using procedures outlined in the Standard Methods for the Examination of Water and Wastewaters. The results revealed that the rivers are polluted with Fe and Cu, accompanied by very high levels of turbidity (mean = 488 NTU) and total suspended solids (TSS) (mean = 382 mg/L). NH3-N, PO4-P, BOD, and DO levels indicated mild pollution in the waters. Pollution of the rivers is attributable to impacts of artisanal small-scale mining, surface run-off as a result of high intensity rainfall, anthropogenic (indiscriminate waste disposal) and geogenic factors such as dissolution of minerals from the soil zone. It was observed that, if not strictly regulated, turbidity and TSS levels arising mainly from illegal small-scale mining activities could lead to shutdowns of a number of Ghana Water Company Limited treatment plants, leading to water supply challenges in the study area.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Ghana , Contaminantes Químicos del Agua/análisis , Calidad del Agua
9.
Environ Monit Assess ; 193(11): 717, 2021 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-34642865

RESUMEN

Decreasing levels of water quality and elevated concentrations of heavy metals in freshwaters can pose global challenges for drinking water sources. Multivariate statistical techniques have been applied on data matrices of water quality and heavy metals for keen characterization of their spatio-temporal variations, exploration of latent factors, and identification of pollution sources. Non-metric multidimensional scaling (nMDS), canonical correlation analysis (CCA), and structural equation modeling (SEM) were employed to process data matrices of the water quality and heavy metals with 14 parameters measured at 13 sampling sites in Dongjianghu Lake in March, June, August, and December 2016. The sampling sites were grouped into three clusters using the nMDS, suggesting that the increasing order of the water quality levels was approximately midstream < downstream < upstream and lake. The CCA of 14 parameters proved that the Escherichia coli, CODMn, TP, TN, TEMP, DO, and pH were the latent factors to distinguish the sampling sites, suggesting that the natural disturbances further influenced the lake and upstream, while the anthropogenic activities further influenced the midstream and downstream. The CCA of the heavy metals exhibited that the CODMn, F-, and E. coli were the latent factors of the Cu, Zn, and As, while the DO and TEMP were the latent factors of the Cd. This indicated that the Cu, As, and Zn were mainly associated with the anthropogenic activities, while the Cd was predominantly relative to the natural conditions. The SEM of the water quality and heavy metals showed that the weights of CODMn (28.64%), NH3-N (14.96%), BOD5 (14.32%), TN (12.88%), and TP (10.18%) were higher than those of the pH (8.37%), DO (7.73%), TEMP (2.58%), and E. coli (0.34%). This indicated that the former exhibited strong influences on the heavy metals than the latter. Moreover, the CODMn and BOD5 were the key factors of the heavy metals, which should be attributed to the no-point sources, especially the exploitation mining and mill tailings. The water quality assessment by the nMDS, CCA, and SEM can determine the status, trend corresponding to its standards, and trace latent factors and identify possible pollution sources. The study could provide a guide for water quality evaluation and pollution control.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Escherichia coli , Sedimentos Geológicos , Lagos , Análisis de Clases Latentes , Metales Pesados/análisis , Análisis Multivariante , Contaminantes Químicos del Agua/análisis , Calidad del Agua
10.
Environ Monit Assess ; 193(11): 738, 2021 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-34669048

RESUMEN

The Campos de Palmas Wildlife Refuge (RVS-CP) is a full protection conservation unit (CU) formed by private properties. The present study aimed to use the bioindicators Allium cepa L. (cytotoxicity and mutagenicity tests) and Eisenia fetida (avoidance test) to assess the quality of surface water of the Chopim River within the RVS-CP area and its surroundings during the four seasons of the year. To do so, water samples were collected at five points, four inside the RVS-CP area and a fifth point outside thereof. Samples from all sampling points had cytotoxic effect on A. cepa in at least one season of the year. Such a finding may be related to inadequate management practices (without land-use control) in the areas surrounding the sampling points such as forestry, native fields, pastures, agriculture, and housing areas. As for the animal bioindicator (E. fetida), only points 1 (in the winter) and 5 (in the autumn) were toxic. Concerning mutagenicity, points 1 and 4 (in the spring), 1 and 2 (in the summer), and 3 (in the autumn) showed mutagenic effect on A. cepa meristematic cells, therefore only within the RVS-CP area. Overall, these results show that biomonitoring can be an ally of the residents of the RVS-CP area in controlling management practices, aiming to bring together economic support and conservation of resources, especially water.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Animales , Animales Salvajes , Monitoreo Biológico , Brasil , Monitoreo del Ambiente , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad , Calidad del Agua
11.
Environ Monit Assess ; 193(11): 694, 2021 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-34611737

RESUMEN

The Prairie Pothole Region is one of the most wetland rich areas of the world and has experienced intense disturbance from increased agricultural demands and urban sprawl. This study assessed ponds across the urban gradient for the first time in the region to determine the impacts of urbanization on water quality. Thirty ponds (ten rural, ten peri-urban, and ten urban) were randomly selected and compared based on land use type and the impervious to pervious surface ratio within 1.6 km of each pond. Water quality samples were taken monthly in 2015 and 2016, across 3 and 6 months respectively. Assessment included chemical and physical parameters, which were compared spatially across the gradient and temporally between sampling periods. Results indicate disturbance from urbanization negatively impacts water quality. Spatially across the gradient, rural pond water quality was significantly different from both peri-urban and urban ponds, whereas peri-urban and urban pond water quality was not significantly different. Temporally, differences between water quality parameters and sampling periods indicate that surrounding land use, land cover, and precipitation influence parameter concentrations across the urbanization gradient. Information from this study is useful to water professionals dealing with urban development and sprawl that continue to impact water and natural habitat.


Asunto(s)
Estanques , Calidad del Agua , Ecosistema , Monitoreo del Ambiente , Urbanización
12.
Water Sci Technol ; 84(5): 1125-1135, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34534110

RESUMEN

The Water Network of the National Autonomous University of Mexico (Red del Agua UNAM) and the Program for the Management, Use, and Reuse of Water in UNAM (PUMAGUA) carried out a survey with the aim of knowing the water consumption practices of the university community in its campuses located in the Metropolitan Area of the Valley of Mexico. A sample of 2,095 students, academics, administrative and support staff participated in this survey. The results show that 74% of the sample consume bottled water and that their average spending is between 0.50 and 1 dollar per day (11 to 20 Mexican pesos). The rates of bottled water consumption contrasts with the perception about water quality, since only 13% consider water quality distributed in the water fountains located within university campuses as 'poor' or 'very poor'. The rates of bottled water consumption among university community are similar to the ones reported by studies in Mexico City and in Mexico as a whole, even though UNAM has a Water Observatory that allows people to know in real time water quantity and quality in university campuses.


Asunto(s)
Agua Potable , Universidades , Ingestión de Líquidos , Humanos , México , Calidad del Agua , Abastecimiento de Agua
13.
Environ Monit Assess ; 193(10): 667, 2021 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-34549387

RESUMEN

The sub-Himalayan foothill region is experiencing rapid land-use transformation over the last few decades resulting in the decay of several rivers such as Mahananda, Balason, Sahu, Rakti, Panchanai, Dharala, and Karala. A small rain-fed tributary of Teesta, Karala, has almost decayed in recent years but no notable assessment of its condition has been done to date. This study mainly aims to measure the intensity of human interventions and related responses of Karala through reach-wise, multiple indicator-based assessments. Initially, the reaches have been delineated by segmenting the river into 10 equidistant segments. Characterization of land-use and land-cover has been done for all such reaches. To determine the nature of hydro-geomorphology and water quality of the river 14 indicators are selected and categorized into 3 indices. According to the measured reach-wise mean (Rm), with the highest 4.70 (Reach 1) and lowest 2.21 (R9), it is clear that the need for restoration increases downstream since those areas portray massive deviation from least disturbed conditions (LDC). It is also revealed that the change in the bar area (ID7), vegetation condition (ID3), non-point sources of pollution (NPSP), and channel width (ID8) indicate also an alarming condition within the lower part of the river channel. It is evident that as the river approaches downstream, the natural state of landcover is lost due to intensive human intervention, mostly due to massive land-use transformation reflected in a 600% increase in built-up area in and around the Jalpaiguri region from 1990 to 2020. Hydrologically as well as ecologically sensitive rivers like Karala are the inseparable parts of the sub-Himalayan foothills. Degradation of such, due to, the human alteration would eventually disarrange the entire ecosystem. This easy-to-use, rapid, and coast effective methodology was found useful in distinguishing the extent of alterations by human intervention and the responses of such river systems.


Asunto(s)
Ecosistema , Monitoreo del Ambiente , Humanos , Lluvia , Ríos , Calidad del Agua
14.
J Hazard Mater ; 416: 125961, 2021 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-34492875

RESUMEN

This study investigated the removal of vanadium from mining waters at a closed mine site (Mustavaara, Finland) using granular ferric oxyhydroxide (CFH-12) on pilot scale. Two filter systems, pilot A and pilot B, were placed in different streams, where the influent in pilot A contained a higher and very variable vanadium concentration (6.46-99.1 mg/L), while the pilot B treated influent had lower vanadium concentrations (0.443-2.33 mg/L). The operation periods were 51 days for pilot A and 127 days for pilot B. Water quality analyses revealed that vanadium was efficiently captured in the filter system in both pilots. X-ray fluorescence analysis revealed that the filter beds were not fully saturated with vanadium. X-ray photoelectron spectroscopy confirmed that oxidised vanadium (5+) existed in the used CFH-12 and the carbon content in the used material had increased due to the adsorbed organic compounds. For comparison, lab-scale coagulation experiments were conducted using ferric sulphate for the influent of pilot A (the sampled batch contained 15.9 mg/L V). The optimum coagulant dosage was 350 mg/L (>93% vanadium removal) at the original pH (7.8-7.9) of the influent, whereas the required coagulant amount decreased when the influent pH was adjusted to 4.6-4.8.


Asunto(s)
Vanadio , Contaminantes Químicos del Agua , Hierro , Minería , Compuestos Orgánicos , Calidad del Agua
15.
Environ Monit Assess ; 193(10): 623, 2021 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-34477949

RESUMEN

The aim of the study was to assess the status of groundwater quality of Owerri and environs, for drinking and irrigation purposes. Twenty-two (22) groundwater samples were collected and analyzed for both chemical and physical compositions. The result of the study showed that groundwater in the area is of good quality for drinking purposes, except for pH and Fe, which had higher concentrations in some areas. A weak correlation matrix within the sampled parameters of the groundwater was observed. Hydrogeochemical studies revealed that 91% of the samples are within the geochemical zone of 4 (strong acids (SO4 + Cl) exceed weak acids (CO3 + HCO3)), while 9% are of the geochemical zone of 3 (weak acids (CO3 + HCO3) exceed strong acids (SO4 + Cl)). The study shows an ionic trend of Cl- > Ca2+ > HCO3- > Na+ + K+ > Mg2+ > SO42- and hydrogeochemical facies of Na-Cl, Ca-Cl, Ca-CO3, Mg-Cl, and Mg-HCO3 of 45.5%, 36.4%, 4.5%, 4.5%, and 9.1% respectively. Chloro-alkaline values were negative except for B4 which was positive. The water quality index (WQI) revealed water quality status of excellent (4.5%), good (27.3%), poor (40.9%), and very poor (27.3%). Contamination factor (CF) reveals that the groundwater is slightly polluted while the pollution load index (PLI) revealed no noticeable pollution. Gibbs diagram revealed that the entire samples are within the rock dominance zone. Irrigation suitability studies showed that SAR of the groundwater was of excellent quality; %Na had good quality (27.3%), permissible quality (45.4%), and doubtful quality (27.3%); MH had 86.4% of the groundwater suitable, while 13.6% are not suitable; KR had suitable groundwater (59.1%) and unsuitable (40.9%); while the Wilcox diagram had 72.7% excellent water for irrigation and 27.3% permissible for irrigation. A routine check of groundwater in the study area is recommended.


Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Facies , Humanos , Nigeria , Contaminantes Químicos del Agua/análisis , Calidad del Agua
16.
An Acad Bras Cienc ; 93(4): e20191221, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34495199

RESUMEN

The invasion record for the estuarine bivalve Mytilopsis leucophaeata in Brazil is in Rio de Janeiro city, including the Rodrigo de Freitas Lagoon, where high densities of this invader were registered. This work aimed to (1) assess the composition and structure of the benthic macrofauna associated with this invader in Rodrigo de Freitas Lagoon, (2) analyze the spatiotemporal variation of richness, density and diversity of the associated benthic community, and (3) correlate changes on the density of the associated benthic species with some water quality variables and the density of M. leucophaeata. Clusters of M. leucophaeata were collected monthly (two years) in four sites. Nine taxa associated with M. leucophaeata were found; Heleobia sp. (Gastropoda) and Melita mangrovi (Amphipoda) showed the highest densities. The structure of the benthic macrofauna slightly differed among sampling sites, but not between dry and wet seasons. The water quality parameters, specific patterns of each taxon and high densities of M. leucophaeata contribute to variations in density of the associated species. Oscillations in the densities of M. leucophaeata and the native bivalve Brachidontes darwinianus suggest some agonistic relationship between them, such as a competition for space.


Asunto(s)
Anfípodos , Bivalvos , Animales , Brasil , Estaciones del Año , Calidad del Agua
17.
Environ Monit Assess ; 193(10): 634, 2021 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-34491451

RESUMEN

We studied the water quality of the riparian firefly sanctuary of Sungai Rembau, or Rembau River, in Negeri Sembilan, Malaysia, from January 2018 to November 2018 to determine the possible influence of the physico-chemical characteristics of the water on the firefly populations living within the sanctuary. We set up a total of five water quality sampling stations and 10 firefly sampling stations along the river. Dissolved oxygen (DO), temperature, pH and electrical conductivity (EC) were measured in situ, while chemical oxygen demand (COD), total suspended solids (TSS), biochemical oxygen demand (BOD) and ammonia-nitrogen (NH3-N) were analysed in the laboratory. Firefly samples were collected using a sweep net at both day and night for 1 min. Sungai Rembau was categorized as Class II on the Malaysian water quality index (WQI), which indicates slight pollution. Except for EC and DO, the water quality parameter values were not significantly different (p > 0.05) between the sampling stations. A total of 529 firefly individuals consisting of Pteroptyx tener (n = 525, 99.24%), P. malaccae (n = 3, 0.57%) and P. asymmetria (n = 1, 0.19%) were collected. There was significant correlation between firefly abundance and BOD (r = - 0.198, p < 0.05), NH3-N (r = - 0.150, p < 0.05) and pH (r = 0.408, p < 0.05). The results show that the firefly populations in Sungai Rembau are sensitive to organic compounds, which may be present in the form of pollutants from anthropogenic activities near their natural habitat.


Asunto(s)
Ríos , Contaminantes Químicos del Agua , Animales , Monitoreo del Ambiente , Luciérnagas , Humanos , Malasia , Contaminantes Químicos del Agua/análisis , Calidad del Agua
18.
Mar Pollut Bull ; 171: 112870, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34507203

RESUMEN

In recent decades the declining health of the Great Barrier Reef has led to a number of government policies being implemented to reduce pollutant loads from the adjacent agricultural-based catchments. There is increasing use of cost-effectiveness measures to help prioritise between different programs and actions to reduce pollutants, given limited resources and the scale of the issues. However there are a small number of primary studies available, and the consistency of cost-effectiveness measures and their application is limited, particularly given the various uncertainties that underlie the measures. Unlike Europe and the United States of America water policy or benefit transfer approaches, there are no procedural guidance studies that must be followed in the context of the Great Barrier Reef catchments. In this study we review the use of cost effectiveness estimates for pollutant reduction into the Great Barrier Reef in the context of a benefit transfer framework, where estimates of costs from a particular case study are transferred to various scenarios within different catchments. The conclusions suggest a framework be developed for the Great Barrier Reef, which is consistent, transparent, and rigorous.


Asunto(s)
Agricultura , Calidad del Agua , Arrecifes de Coral , Análisis Costo-Beneficio , Agua , Contaminación del Agua
19.
Environ Monit Assess ; 193(10): 629, 2021 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-34490509

RESUMEN

Continuous vigilance of water quality is essential throughout water supply and storage systems to ensure safe water quality and safeguard consumer health. In the present study, sixty-three sampling locations in Sharjah, UAE, were assessed for possible water quality variations from water supply through utilized water storage tanks in buildings. All investigated physico-chemical parameters were within national water quality guidelines except for free residual chlorine (< 0.2 mg/L in 30% of samples), mainly in storage tanks. Compliance of metal concentrations varied with metal type, sampling locations, and points. Highest compliance was reported for manganese, copper, nickel, chromium, and least for iron, lead, and cadmium. No major variations in physico-chemical water quality could be statistically observed using analysis of variance when tracing the water from lower tanks to upper tanks, yet significant variations for turbidity (p = 0.006) were observed from mains to lower tanks and for water temperature (p = 0.026), residual chlorine (p = 0.001), turbidity (p = 0.048), chromium (p = 0.019), copper (p = 0.002), manganese (p = 0.012), and zinc and lead (p = 0.000) from mains to upper tanks. As for investigated microbiological parameters, all investigated samples were completely free from total and fecal coliforms and Pseudomonas aeruginosa. Exhibited ranges of yeasts and molds (0-28 CFU/100 mL) and heterotrophic plate counts (0-356 CFU/mL), though non-enforceable parameters, were always lower than recommended water quality guidelines. Furthermore, Pearson correlation tests exhibited significant correlations for water temperature versus yeasts and molds and electrical conductivity versus sodium and potassium. Statistically (using t-tests), mean heterotrophic plate counts were slightly higher in lower tanks compared to other sampling points. Additionally, mean heterotrophic plate counts were significantly higher in larger tanks exceeding 2000 gallons, in square/rectangular shaped tanks, in tanks exceeding 10 years of age, and in concrete tanks with higher water temperatures. Re-chlorination, proper cleaning, as well as maintenance or upgrade of water storage tanks remain advisable to ensure safe water at point of use.


Asunto(s)
Microbiología del Agua , Calidad del Agua , Monitoreo del Ambiente , Emiratos Árabes Unidos , Abastecimiento de Agua
20.
Water Res ; 204: 117556, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34481284

RESUMEN

Water quality events such as increases in stormwater or wastewater effluent in drinking water sources pose hazards to drinking water consumers. Stormwater and wastewater effluent enter Lake Mead-an important drinking water source in the southwest USA-via the Las Vegas Wash. Previous studies have applied machine learning and online instruments to detect contamination in water distribution systems. However, alert systems at drinking water intakes would provide more time for corrective action. An array of online instruments measuring pH, conductivity, redox potential, turbidity, temperature, tryptophan-like fluorescence, UV absorbance (UVA254), TOC, and chlorophyll-a was fed raw water directly from Lake Mead. Wastewater effluent, dry weather Las Vegas Wash, and storm-impacted Las Vegas Wash samples were blended into the instrument inlets at known ratios to simulate three types of adverse water quality events. Data preprocessing was conducted to correct for diurnal patterns or instrument drift. Supervised machine learning was conducted using previously published models in R. Ninety-nine models were screened on the raw data. Eight high-performing models were evaluated in-depth and optimized. Weighted k-Nearest Neighbors, Single C5.0 Ruleset, Mixture Discriminant Analysis, and an ensemble of these three models had accuracy over 97% when assigning test set data among three classes (Normal, Event, or Maintenance). The ensemble detected all event types at the earliest timepoint and had one false positive that was not a lag error (i.e., consecutively following a true positive). Omitting Maintenance, the Adaboost model had over 99% test set accuracy and zero false positives that were not lag errors. Data preprocessing was beneficial, but the optimal methods were model-specific. All nine water quality variables were useful for most models, but UVA254 and turbidity were most important.


Asunto(s)
Purificación del Agua , Agua , Monitoreo del Ambiente , Aprendizaje Automático , Aguas Residuales , Calidad del Agua
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