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1.
Sci Total Environ ; 750: 141284, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182170

RESUMO

Regular monitoring of drinking water quality is vital to identify contamination of potable water supplies. Testing for microbial contamination is important to prevent transmission of waterborne disease, but establishing and maintaining a water quality monitoring programme requires sustained labour, consumables and resources. In low resource settings such as developing countries, this can prove difficult, but measuring microbial contamination is listed as a requirement of reaching the UN's Sustainable Development Goal 6 for water and sanitation. A nine-month water quality monitoring programme was conducted in rural Malawi to assess the suitability of tryptophan-like fluorescence (TLF), an emerging method for rapidly detecting microbial contamination, as a drinking water quality monitoring tool. TLF data was compared with thermotolerant coliforms (TTCs, E. coli) and inorganic hydrochemical parameters. A large (n = 235) temporal dataset was collected from five groundwater drinking water sources, with samples collected once or twice weekly depending on the season. The results show that TLF can indicate a broader contamination risk but is not as sensitive to short term variability when compared to other faecal indicators. This is likely due to a broad association of TLF with elevated DOC concentrations from a range of different sources. Elevated TLF may indicate preferential conditions for the persistence of TTCs and/or E. coli, but not necessarily a public health risk from microbial contamination. TLF is therefore a more precautionary risk indicator than microbial culturing techniques and could prove useful as a high-level screening tool for initial risk assessment. For widespread use of TLF to be successful, standardisation of TLF values associated with different levels of risk is required, however, this study highlights the difficulties of equating TLF thresholds to TTCs or E. coli data because of the influence of DOC/HLF on the TLF signal.


Assuntos
Água Potável , Monitoramento Ambiental , Escherichia coli , Fluorescência , Humanos , Malaui , Triptofano , Microbiologia da Água , Qualidade da Água , Abastecimento de Água
2.
Sci Total Environ ; 752: 141846, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32892045

RESUMO

This paper examines seasonal variations in faecal contamination of drinking water sources in the Jirapa and Kassena-Nankana Municipalities of Ghana. Data collection involved a survey of 568 households, testing of faecal coliform concentrations in drinking water source samples (141 in the rainy season, 128 in the dry season), in-depth interviews with key water stakeholders, and field observation to identify sources of faecal contamination. From the water quality testing, faecal coliforms were detected in all source types, including 'treated' pipe-borne water. Contamination was significantly higher in the rainy season than in the dry season (P < 0.05) with 51.8% of water samples in the rainy season and 27.3% in the dry season failing to meet the World Health Organisation and Ghana Standard Authority guideline on faecal coliform concentrations in drinking water sources. The proportion of population at risk of faecal contamination in the rainy season was 41.5% compared to 33.1% in the dry season. We argue that in Ghana and Sub-Saharan Africa at large, water surveillance agencies risk underestimating population exposed to faecal contamination through drinking water sources if monitoring is only done in the dry season. To avoid this, we recommend seasonal monitoring of faecal concentration in drinking water sources. However, in periods of limited resources, monitoring is most appropriate in the rainy season when the risk of contamination is high.


Assuntos
Água Potável , Cidades , Água Potável/análise , Gana , Estações do Ano , Microbiologia da Água , Qualidade da Água , Abastecimento de Água
3.
Sci Total Environ ; 753: 141768, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32896733

RESUMO

Natural sunlight is a vital environmental element and plays a significant role in the ecological storage of reclaimed water (RW), but its impacts on RW quality are poorly understood. In this study, sunlight-induced changes in RW with a focus on dissolved organic matter (rDOM) and 52 residual micropollutants were investigated in the field during the summer and winter seasons. The results indicated that sunlight exposure led to the dissipation of chromophoric DOM (CDOM) in the summer (55% loss) and winter (19% loss) after 14 consecutive sunny days. During open storage of RW, CDOM absorption in UVC regions was preferentially removed in the summer, while during the winter there was preferential removal of CDOM in UVA regions. The results also showed higher fluorescent DOM (FDOM) removal in summer than in winter (49% and 28%, respectively). Results in both seasons indicated that humic acid-like compounds were the most photolabile fractions and were preferentially removed under sunlight exposure. Sunlight also induced attenuation of micropollutants in the summer and winter at reductions of 66% and 24% from the initial values, respectively. Significant attenuation (>75%) was only observed for endocrine-disrupting chemicals, pharmaceuticals, and sunscreens in the summer, but they accounted for 76% of the total concentrations. Vibrio fischeri toxicity tests demonstrated that sunlight constantly decreased the luminescent bacteria acute toxicity of RW, which was estimated to be caused mainly by the sunlight-induced changes of FDOM and CDOM, while the detected micropollutants could only explain 0.02%-2% of acute toxicity. These findings have important implications regarding our understanding of the ecological storage of reclaimed water and the contribution of management strategies.


Assuntos
Luz Solar , Água , Água Doce/análise , Substâncias Húmicas/análise , Qualidade da Água
4.
Sci Total Environ ; 753: 141776, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32911162

RESUMO

Globally, consumers judge their drinking water through its aesthetic qualities because tastes, odors, and appearances are readily detectable by untrained consumers. Consumer feedback is critical to the water industry for efficient resolution of aesthetic water quality issues, although consumer descriptions of taste and odor issues can sometimes be unfocused or confusing. A user-friendly approach can facilitate consumer communications to utilities in the challenging task of describing drinking water taste and odor issues. The purpose of this study was to develop a list of taste and odor descriptors and test a novel "check-if-apply" approach to describe drinking water quality. The final list contained 28 individual and/or groups of descriptors. 75 participants tested water samples impacted by various tastants or odorants: duplicate samples of chloraminated tap water, tap water with heptanal, tap water with 2-methylisoborneol (MIB), tap water with NaCl, bottled water, and bottled water with CuSO4. Participants used a 9-point hedonic scale (1 = 'dislike extremely'; 9 = 'like extremely') to rate overall liking of each sample, and they used the check-if-apply list to describe the taste or odor. Participants also answered a brief questionnaire and used a 5-point scale (1 = 'very difficult'; 5 = 'very easy') to evaluate their experience using the check-if-apply list. Significant differences were observed in acceptability and sensory profile of samples (p-value <0.05). Tap water with MIB had the lowest acceptability mean score (3.43 ± 1.74), while flavorless bottled water had the highest acceptability mean score (6.23 ± 1.47). 'Salty', 'metallic', 'chemical' and 'musty/earthy' were the dominant descriptors for NaCl, CuSO4, heptanal, and MIB, respectively. Most participants (81%) found the check-if-apply list as 'somewhat easy' to 'very easy' to use (mean = 3.44 ± 1.07) and suggested it as a user-friendly lexicon for consumers and utilities to communicate about water quality.


Assuntos
Água Potável , Água Potável/análise , Estética , Humanos , Odorantes/análise , Paladar , Qualidade da Água
5.
Chemosphere ; 262: 127851, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32781333

RESUMO

A monitoring study was carried out in three agriculturally influenced microcatchments in Costa Rica during 2012-2014, for pesticides and water quality parameters. A total of 42 pesticides were analyzed, detecting the following in water samples: two herbicides (oxyfluorfen, diuron), four insecticides (carbofuran, chlorpyrifos, oxamyl, ethion), and two fungicides (thiabendazole, carbendazim); while in sediment samples only the insecticides, chlorpyrifos and cypermethrin were found. Water quality was also assessed by the Canadian Council of Ministers of the Environment Water Quality Index and the National Sanitation Water Quality Index, the first one classified most of the sampling point as marginal and poor quality while the second one classified most of them as good quality, the most affected parameters were nitrate, phosphorous, suspended solids and organic matter content. The results suggest that the water quality in the microcatchments seems to be affected by the nearby agricultural and urban activities in the region.


Assuntos
Monitoramento Ambiental , Praguicidas/análise , Poluentes Químicos da Água/análise , Agricultura , Canadá , Carbamatos , Clorpirifos , Diurona , Herbicidas/análise , Inseticidas/análise , Compostos Organotiofosforados , Rios , Estados Unidos , Qualidade da Água
6.
Sci Total Environ ; 753: 141884, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33207442

RESUMO

Understanding how plants and earthworms regulate soil-based ecosystem services can guide design and management of built environments to improve environmental quality. We tested whether plant and earthworm activity results in trade-offs between soil carbon (C) retention and water quality. In a 2 × 2 factorial random block design, we introduced shrubs (Aronia melanocarpa) and earthworms (Lumbricus terrestris) to turfgrass (Lolium perenne) sandy loam mesocosms in a greenhouse. We measured soil respiration and soil microclimate every two weeks and leachate every two months. After 15 months, we assessed C and nitrogen (N) in bulk soil and aggregates (> 2000, 2000-250, 250-53 µm). Turfgrass mesocosms with earthworms retained less soil C (6.10 ± 0.20 kg/m2), especially when warmer. Soils planted with shrubs were drier and had 7% lower mean respiration rates than soils without shrubs. Turfgrass mesocosms with both shrubs and earthworms retained more soil C (6.66 ± 0.25 kg/m2), even when warmer, and held ~1.5 times more C in >2 mm aggregates than turfgrass-only mesocosms. Turfgrass mesocosms with shrubs and earthworms leached nitrate-N with increased respiration and retained phosphate-P and dissolved organic carbon (DOC) when wetter. In contrast, turfgrass mesocosms with only shrubs had the opposite response by leaching less nitrate-N with increased respiration, and more phosphate-P and DOC when wetter. Overall, shrub and earthworm activity in turfgrass mesocosms led to soil C-nutrient retention trade-offs. Our results reveal potential challenges in managing built environments to both retain soil C and improve water quality.


Assuntos
Oligoquetos , Animais , Carbono/análise , Ecossistema , Solo , Qualidade da Água
7.
J Environ Manage ; 277: 111498, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33069153

RESUMO

A challenge for current surface water restoration and management in China is acquiring the source information for complex pollution scenarios in order to develop effective control strategies. As an important part of dissolved organic matter, chromophoric dissolved organic matter (CDOM) contains unique chemical signals related to various pollution sources. Spectral methods such as fluorescence excitation-emission matrices coupled with parallel factor analysis enable rapid and low-cost CDOM characterization for source tracking. In this study, a typical small-sized river flowing through mixed land-use regions in southeastern China, the Lujiang River, was investigated to determine the responses of CDOM to spatiotemporal factors. The effects of land-use patterns were reflected by the fluorescent components of terrestrial and sewage substances. A high and stable proportion of terrestrial-like components (C1 + C2) in each sampling period (i.e., March: 47.6 ± 5.7% and October: 44.3 ± 2.7%) indicated a high input of non-point source (NPS) pollution from both agriculture and urban areas. In addition, the difference in solar radiation intensity induced by climate and air quality changes was also reflected by variability in the photodegradation product component (C3) of terrestrial precursors between October (24.8 ± 2.6%) and March (4.5 ± 2.0%), suggesting that terrestrial components could be a sensitive indicator for NPS pollutant monitoring. Increased sewage impact in downstream regions was reflected by a spike in the tryptophan-like component (C4); temporal variations in C4 (paired t-Test, p < 0.005) also indicated that sewage substances were more prone to removal by microbial activity in warmer seasons. The dynamics of C4 could serve as a good indicator of sewage disposal performance. The results of this study demonstrate that CDOM data have important practical applications for existing water restoration campaigns in southeastern China, as well as substantial potential for routine water quality monitoring.


Assuntos
Rios , Água , China , Espectrometria de Fluorescência , Qualidade da Água
8.
J Environ Manage ; 277: 111427, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33069154

RESUMO

Proper identification of critical source areas (CSAs) is important for economic viability of any best management practices (BMPs) aimed at reducing sediment and phosphorus loads to receiving water bodies. Both continuous and event-based hydrologic and water quality models are widely used to identify and assess CSAs, however, their comparative assessment is lacking. In this study, we have used continuous Soil and Water Assessment Tool (SWAT) and event-based Agriculture Non-Point Source (AGNPS) pollution models to identify CSAs for sediment and phosphorus in a watershed in Ontario, Canada. Along with their original version, both models were re-conceptualized to incorporate saturation excess mechanism of runoff generation, which is also refereed as variable source area (VSA) integration. The models were set-up using high resolution spatial, crop- and land-management, and meteorological dataset; and calibrated with reasonable accuracy against streamflow, sediment and phosphorus concentration data at multiple locations. Threshold value (t-value) approach was used to identify CSA areas in the watershed. Results showed that both models were in agreement (up to 96% of fields) that summer season did not constitute hot-moments (<6% of the watershed area as CSAs) for both sediment and phosphorus. SWAT models identified winter (~50% of watershed area as CSA) and AGNPS models identified early spring (~50% of watershed areas as CSAs) season as the hot-moment for both sediment and phosphorus. Contrasting result, as indicated by low (1%) matching in field CSA potential, was observed in autumn season. In the same season, VSA integrated SWAT and AGNPS models showed better matching (43% for sediment and 31% for phosphorus), highlighting the importance of VSA integration in the models. Qualitative validation of model-based CSA potential with oblique aerial-photograph-based CSA potential in two soil moisture conditions (wetter and drier) indicated slightly better performance of the SWAT models, and over-prediction of the AGNPS models. However, a more comprehensive analysis based on more detailed field observations is needed to further confirm the results.


Assuntos
Agricultura , Fósforo , Monitoramento Ambiental , Modelos Teóricos , Ontário , Fósforo/análise , Solo , Qualidade da Água
9.
J Environ Manage ; 277: 111342, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33080433

RESUMO

Water quality is continuously changing because of anthropogenic origin of point and diffuses (non-point) pollution sources. Most of the time diffuse sources are not considered for rationalization of sampling sites as their accurate estimation is tedious and data intensive. The estimation of diffuse pollution is conventionally carried out using observed water quality data. These conventional approaches are data intensive and demands detailed information for a considerably long-time horizon and hence becomes challenging to implement in data-scarce regions. Also, diffuse pollution sources are characterized by spatio-temporal heterogeneity as they depend upon seasonal behavior of precipitation. The present study proposes an innovative semi-empirical approach of Seasonal Export Coefficients (SECs) for estimation of diffuse pollution loads, especially for tropical countries like India. This approach takes into account the effect of seasonality on the estimation of diffuse pollution loads, by considering seasonal heterogeneity of terrain and precipitation impact factors and land use applications. This seasonal heterogeneity is then tested for its possible impact on rationalization of water quality monitoring locations for Kali River basin in India. The SECs are estimated for available water quality dataset of 1999-2000 and are further used for simulation of nutrient loading for experimental years 2004-2005, 2009-2010, and 2014-2015. The resulting SECs for Kali river basin are: 2.03 (agricultural), 1.44 (fallow), and 0.92 (settlement) for monsoonal nitrate; while for non-monsoonal nitrate, SECs are 0.51 (agricultural), 0.23 (fallow), and 0.10 (settlement). The monsoonal phosphate SECs for land use classes - agricultural, fallow and settlement are 1.01, 0.68, and 0.25, while non-monsoonal phosphate SECs are 0.27, 0.14 and, 0.03 respectively. The seasonal variation of diffuse pollution sources is effectively captured by SECs. The proposed approach, by considering both point and diffuse pollution, is found efficient in determining optimum locations and number of monitoring sites where seasonal variations are found evident during experimental years.


Assuntos
Poluentes Químicos da Água , Qualidade da Água , Monitoramento Ambiental , Índia , Racionalização , Rios , Estações do Ano , Água , Poluentes Químicos da Água/análise , Poluição da Água/análise
10.
J Environ Manage ; 277: 111450, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33031997

RESUMO

Ponds are a typical feature of many villages in the subtropics, and have been widely used as important sources of water for agriculture, aquaculture and groundwater recharge, as well as enhancing village resilience to floods and drought. Currently many village ponds are in a very poor state and in dire need of rejuvenation. This paper assesses the current water quality status and ecological health of twelve sub-tropical village ponds, situated in western Uttar Pradesh, India. This assessment is used to evaluate their wastewater treatment needs in relation to potential village uses of the water. Physico-chemical (Secchi depth, Total phosphorus and Total nitrogen) and biological (Phytoplankton chlorophyll-a) indicators highlight hypertrophic conditions in all the ponds. The study indicates that the status of village ponds requires significant investments in wastewater treatment to restore their use for many purposes, including aquaculture, although some may still be acceptable for irrigation purposes, as long as pathogenic bacteria are not abundant. We propose increased implementation of decentralised systems for wastewater treatment, such as septic tanks and constructed wetlands, to reduce the organic and nutrient loads entering village ponds and allow their use for a wider range of purposes.


Assuntos
Água Subterrânea , Qualidade da Água , Índia , Tanques , Abastecimento de Água
11.
J Environ Manage ; 277: 111413, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33035938

RESUMO

Surface waters listed on impaired waters (303 d) lists due to pathogen contamination pose a significant environmental and public health burden. The need to address impairments through the Total Maximum Daily Load (TMDL) process has resulted in method developments that successfully identify nonpoint fecal pollution sources by maximizing available resources to improve water quality. However, the ability of those methods to effectively and universally identify sources of fecal pollution requires further evaluation. The objective of this research was to assess the usefulness of a previously described multivariate statistical approach to identify common patterns influencing fate and transport of fecal pollutants from sources to receiving streams using the Tuckasegee River watershed in Western North Carolina as a test watershed. Two streams were routinely monitored using a targeted sampling approach to assess fecal pollution extent and identify nonpoint sources using canonical correlation and canonical discriminant analyses. Fecal pollution in the watershed varied spatially and temporally with significantly higher fecal coliform concentrations observed in Scott Creek (f = 9.49, p = 0.002) and during the summer months (f = 14.8, p < 0.0001). Canonical correlations described 62-67% of water quality variability and indicate that fecal pollution in portions of the watershed are influenced by stormwater runoff and fecal indicator bacteria resuspension from sediment, while fecal pollution in other portions are influenced by soil erosion and surface runoff. Canonical discriminant analyses indicate that LULC significantly influences the nature and extent of fecal pollution. These results demonstrate that chemical parameters are useful predictors of fecal pollution and can help identify nonpoint fecal pollution sources in relation to land use patterns and land management practices. This approach to water quality monitoring program design and data analysis may effectively and efficiently identify parameters that best predict fecal pollution to aid in development and implementation of effective TMDLs to remediate impaired waters.


Assuntos
Monitoramento Ambiental , Rios , Fezes , Análise Multivariada , North Carolina , Microbiologia da Água , Poluição da Água/análise , Qualidade da Água
12.
Sci Total Environ ; 751: 141618, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-33167190

RESUMO

Some wastewater sources, such as agricultural waste and runoff, and industrial sewage, can degrade water quality. This study summarises the sources and corresponding mechanisms that trigger eutrophication in lakes. Additionally, the trophic status index and water quality index (WQI) which are effective tools for evaluating the degree of eutrophication of lakes, have been discussed. This study also explores the main nutrients (nitrogen and phosphorus) driving transformations in the water body and sediment. Lake Erhai was used as a case study, and it was found to be in a mesotrophic state, with N and P co-limitation before 2006, and only P limitation since 2006. Finally, effective measures to maintain sustainable development in the watershed are proposed, along with a framework for an early warning system adopting the latest technologies (geographic information systems (GIS), remote sensing (RS)) for preventing eutrophication.


Assuntos
Eutrofização , Lagos , China , Monitoramento Ambiental , Nitrogênio/análise , Fósforo/análise , Qualidade da Água
13.
Sci Total Environ ; 751: 141636, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32882551

RESUMO

Several risk scoring and ranking methods have been applied for the prioritization of micropollutants, including pesticides, and in the selection of pesticides to be regulated regionally and nationally. However, the effectiveness of these methods has not been evaluated in Japan. We developed a risk prediction method to select pesticides that have a high probability of being detected in drinking water sources where no monitoring data is available. The risk prediction method was used to select new pesticides for the 2013 Primary List in the Japanese Drinking Water Quality Guidelines. Here, we examined the effectiveness of the method on the basis of the results of water quality examinations conducted by water supply authorities across Japan, and studied ways to improve the risk prediction method. Of the 120 pesticides in the 2013 Primary List, 80 were detected in drinking water sources (raw water entering water treatment plants). The rates of detection of the newly selected pesticides and previously listed pesticides were not significantly different: 64% and 68%, respectively. When the risk predictor was revised to incorporate degradability of dry-field pesticides and current pesticide sales data, the rate of detection of pesticides selected as having a high risk of detection improved from 72% to 88%. We prepared regional versions of the Primary List using the revised risk predictors and verified their utility. The number of listed pesticides varied greatly by region, ranging from 32 to 73; all regional lists were much shorter than the national Primary List. In addition, 55% to 100% of the pesticides detected in each region were included in a Regional Primary List. This work verifies the ability of the risk prediction method to screen pesticides and select those with a high risk of detection.


Assuntos
Água Potável , Praguicidas , Poluentes Químicos da Água , Monitoramento Ambiental , Japão , Praguicidas/análise , Poluentes Químicos da Água/análise , Qualidade da Água
14.
Chemosphere ; 262: 127897, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32791371

RESUMO

This paper investigates the dynamics between basalt weathering and heavy metal accumulation through a comparative study of 37 small basaltic watersheds within different climate zones in the Yungui (the Pearl River Basin in southwest China), Xuyi (the Huaihe River Basin in east China) and Leiqiong regions (Hainan Island in south China). From a comprehensive sampling regime of stream water, riverbed sediments and bedrock, this study shows that the concentrations of heavy metals in river water are far below the national surface water quality standard and WHO quality standard for drinking water, indicating no significant ecological risk for water body in these basaltic areas. In contrast, the riverbed sediments exhibit varying degrees of heavy metal enrichment in the process of weathering from bedrock to sediments: without enrichment for Cr, Ni, Cu and Zn, but significant enrichment for Cd, As and Pb. Cd exhibits the largest ecological risk of all the heavy metals in the basaltic watersheds especially in the Yungui region, which can be mainly attributed to the high geological background values in this area. Comparative studies of some major basalt watersheds in the world show that temperature, runoff and elevation differences significantly affect the chemical weathering rates and thus the accumulation of heavy metals.


Assuntos
Monitoramento Ambiental , Metais Pesados/química , Poluentes Químicos da Água/química , China , Água Doce , Sedimentos Geológicos , Geologia , Metais Pesados/análise , Medição de Risco , Rios , Silicatos , Poluentes Químicos da Água/análise , Qualidade da Água , Tempo (Meteorologia)
15.
Chemosphere ; 262: 127904, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799153

RESUMO

Manganese accumulated in corrosion scales on drinking water distribution systems (DWDSs) can be released into bulk water, causing discolouration and thereby leading to customer concerns about drinking water quality. A static release experiment was conducted on iron pipe scales under three different temperatures, pH values, alkalinity values, sulfate (SO42-) concentrations, and disinfectants to study the separate effect of these factors on Mn release from pipe scales under stagnant conditions. Results showed that more Mn was released from corrosion scales under the conditions of lower pH, lower alkalinity, higher temperature, and higher SO42- concentrations. Three commonly used disinfectants, sodium hypochlorite (NaClO), chlorine dioxide (ClO2), and monochloramine (NH2Cl) were found to inhibit the release of Mn from iron corrosion scales, with the ranked order of inhibitory effect of ClO2≈NaClO > NH2Cl under the same CT (product of disinfectant concentration and contact time) value. The orthogonal experimental results indicated that SO42- and alkalinity had extremely significant effects on the release of Mn from pipe scales, while pH and disinfectant type had a significant impact on the release of Mn from pipe scales. Thus, the SO42- concentration and alkalinity of the bulk water should be determined to avoid excessive release of Mn into drinking water. However, further investigation of the effect of disinfectants on Mn release in DWDSs is necessary. This research helps establish a systematic understanding of the influential factors in Mn release from pipe scales into bulk water, as well as their significant relationships.


Assuntos
Água Potável/química , Manganês/análise , Poluentes Químicos da Água/análise , Compostos Clorados , Corrosão , Desinfetantes/análise , Concentração de Íons de Hidrogênio , Ferro , Óxidos , Sulfatos/análise , Temperatura , Qualidade da Água , Abastecimento de Água
16.
Environ Monit Assess ; 192(12): 793, 2020 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-33244620

RESUMO

Irrigation water quality has important implications on salinity, ion toxicity, production cost, and crop failures. There is a need for a comprehensive analysis of spatial and temporal dynamics in parameters at a watershed scale. This information is critical for irrigation management in agricultural production. The Lake Uluabat watershed is a significant agricultural area of Turkey, which is studied using monitored water data. Multivariate assessment is performed using cluster analysis (CA), discriminant analysis (DA), principal component analysis (PCA), and factor analysis (FA) to evaluate temporal and spatial variations in water quality in the watershed. The data is processed by clustering, reducing data dimensionality, delineating indicator parameters, assessing source identification, and evaluating temporal changes and spatial patterns. The results show that the most representative discriminant parameters had more than 90.98% validity in both temporal and spatial analyses. Runoff rate (Q) and water temperature (WT) were identified in the temporal study, while spatial analysis showed bicarbonate (HCO3-), sulfate (SO42-), and boron (B3+) as indicators. Salinity, sodicity, boron hazard, and alkalinity affect both spatial and temporal water quality patterns in the watershed. It is observed that continued use of poor-quality irrigation water can adversely affect agriculture and soil health in a watershed. Spatio-temporal relationships in parameters will be useful in sustainable irrigation management and farm planning for improving crop productivity and soil health.


Assuntos
Lagos , Qualidade da Água , Agricultura , Monitoramento Ambiental , Turquia
17.
Mar Pollut Bull ; 160: 111636, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181923

RESUMO

Seagrass are an important marine ecosystem of the Fiji Islands. We confirm six seagrass species from the archipelago and defined five broad categories of seagrass habitat. We report, with high confidence, seagrass meadows covering 59.19 km2 of Fiji's shallow water habitats from literature and this study. Long-term monitoring of seagrass abundance, species composition, and seed banks at eight sentinel sites, found no long-term trends. Examination of key attributes that affect seagrass resilience identified meadows as predominately enduring and dominated by opportunistic species which had moderate physiological resistance, and high recovery capacity. We examined threats to Fiji's seagrass meadows from extreme climatic events and anthropogenic activities using a suite of indicators, identifying water quality as a major pressure. Based on these findings, we assessed existing protections in Fiji afforded to seagrass and their services. This understanding will help to better manage for seagrass resilience and focus future seagrass research in Fiji.


Assuntos
Ecossistema , Qualidade da Água , Fiji
18.
Mar Pollut Bull ; 160: 111651, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181931

RESUMO

Nearshore deterioration of water quality in Pacific coastal waters is a growing problem, associated with increasing urban and industrial sewage discharges, and agricultural runoff. Published water quality studies in the Pacific region are limited in both number and scope, making it difficult to resolve the extent of the issue or quantify the variability of water quality across Pacific islands and countries. This study collected water quality measurements over three years in the coastal waters around the Island of Efate (Vanuatu) with majority of work carried out in Port Vila, its capital. Port Vila is the key urban centre for Vanuatu where the increasing population and pollution inputs are placing substantial pressure on the coastal environment. Highest concentrations of dissolved nutrients and suspended sediments were measured adjacent or near the urban drains that enter the coastal areas along the capital's seafront, highlighting many of the issues around anthropogenic inputs are linked to the increasing urbanisation in Port Vila Bay. We provide baseline data that explores variability of coastal water quality and these types of datasets for Pacific islands are a first step towards facilitating development of long-term monitoring programmes and informing coastal zone management decision making.


Assuntos
Urbanização , Qualidade da Água , Agricultura , Monitoramento Ambiental , Ilhas do Pacífico , Vanuatu
19.
Environ Monit Assess ; 192(12): 789, 2020 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-33241485

RESUMO

Surface water eutrophication due to excessive nutrients has become a major environmental problem around the world in the past few decades. Among these nutrients, nitrogen and phosphorus are two of the most important harmful cyanobacterial bloom (HCB) drivers. A reliable prediction of these parameters, therefore, is necessary for the management of rivers, lakes, and reservoirs. The aim of this study is to test the suitability of the powerful machine learning (ML) algorithm, random forest (RF), to provide information on water quality parameters for the Tri An Reservoir (TAR). Three species of nitrogen and phosphorus, including nitrite (N-NO2-), nitrate (N-NO3-), and phosphate (P-PO43-), were empirically estimated using the field observation dataset (2009-2014) of six surrogates of total suspended solids (TSS), total dissolved solids (TDS), turbidity, electrical conductivity (EC), chemical oxygen demand (COD), and biochemical oxygen demand (BOD5). Field data measurement showed that water quality in the TAR was eutrophic with an up-trend of N-NO3- and P-PO43- during the study period. The RF regression model was reliable for N-NO2-, N-NO3-, and P-PO43- prediction with a high R2 of 0.812-0.844 for the training phase (2009-2012) and 0.888-0.903 for the validation phase (2013-2014). The results of land use and land cover change (LUCC) revealed that deforestation and shifting agriculture in the upper region of the basin were the major factors increasing nutrient loading in the TAR. Among the meteorological parameters, rainfall pattern was found to be one of the most influential factors in eutrophication, followed by average sunshine hour. Our results are expected to provide an advanced assessment tool for predicting nutrient loading and for giving an early warning of HCB in the TAR.


Assuntos
Fósforo , Qualidade da Água , Monitoramento Ambiental , Eutrofização , Aprendizado de Máquina , Nitrogênio/análise , Fósforo/análise , Vietnã
20.
Environ Monit Assess ; 192(12): 778, 2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-33230631

RESUMO

Quarrying and crushing activities constitute a major threat to the environment and occupational health of the workers in Jaflong, Sylhet. This study aims to determine the environmental sustainability of stone quarrying and crushing activities considering four dominant environmental components, viz. physicochemical parameters of water, PM2.5 and PM10, sound, and land use land cover (LULC). Water quality was measured in a seasonal variation, and air and sound data were collected in an 8-h period of every weekday of 2 months while LULC data were also collected from 1999 to 2019 with 5 years of interval. Water quality index (WQI) and cluster analysis were applied to classify the pollution sources while inverse distance weighting (IDW) and weighted overlay were used to show the vulnerable zone. All the parameters were considered with the established limit of WHO. WQI detects that the sampling stations located near the quarrying site were responsible for the deterioration of the water quality. Cluster analysis identified that the S8 and S10 sites were heavily susceptible to air and sound pollution. IDW and WO ranked the south-western lower stream and tribal village located at the north-western side as moderately to highly polluted. Correlation analysis illustrated that the values of air and sound parameters were concentrated above the permissible limit. Besides, LULC change revealed the significant lowering trend of vegetation and water bodies whereas it shows the upward trend of barren land and settlement. Finally, the extensive quarrying and crushing activities without any safety measure lead to breaking the environmental sustainability as well as workers and nearby dwellers were exposed to several respiratory diseases.


Assuntos
Monitoramento Ambiental , Qualidade da Água , Bangladesh , Humanos , Rios , Estações do Ano
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