Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.654
Filtrar
1.
Chemosphere ; 242: 125272, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896182

RESUMO

Eutrophication pollution seriously threatens the sustainable development of Lake Taihu, China. In order to identify the primary parameters of water quality and the potential pollution sources, the water quality dataset of Lake Taihu (2010-2014) was analyzed with the water quality index (WQI) and multivariate statistical analysis methods. Principle component analysis/factor analysis (PCA/FA) and correlation analysis screened out five significant water quality indicators, i.e. potassium permanganate index (CODMn), total nitrogen (TN), total phosphorus (TP), chloride ion (Cl-) and dissolved oxygen (DO), to represent the whole datasets and evaluate the water quality with WQI. Since northwestern of Lake Taihu was the most heavily polluted area, the parameters of the water quality were analyzed to further explore the potential sources and their contributions. Five potential pollution sources of northwestern lake were identified, and the contribution rate of each pollution source was calculated by the absolute principal component score-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) models. In brief, the PMF model was more suitable for pollution source apportionment of the northwestern lake, and the contribution rate was ranked as agricultural non-point source pollution (26.6%) > domestic sewage discharge (23.5%) > industrial wastewater discharge and atmospheric deposition (20.6%) > phytoplankton growth (16.0%) > rainfall or wind disturbance (13.4%). This study might provide useful information for the optimization of water quality management and pollution control strategies of Lake Taihu.


Assuntos
Monitoramento Ambiental/métodos , Lagos/química , Modelos Estatísticos , Poluentes Químicos da Água/análise , Qualidade da Água , China , Interpretação Estatística de Dados , Monitoramento Ambiental/estatística & dados numéricos , Eutrofização , Análise Fatorial , Modelos Lineares , Análise Multivariada , Análise de Componente Principal
2.
Chemosphere ; 242: 125269, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896199

RESUMO

The occurrence and distribution of 14 antibiotics in the surface water and sediment of Nansi Lake's inflowing rivers were studied. The concentrations of the antibiotics in the sediment and water were not detected (ND)-193,440 ng kg-1 and ND-694 ng L-1, respectively, and ofloxacin was identified as the main antibiotic. The target antibiotics were identified at decreased levels in the study area compared with the inflowing rivers of other lakes. The decreased antibiotic concentrations resulted from the dilution effect, strong biodegradation, and rapid photolysis during the wet season. The spatial variations were due to the differences in regional contributions; the concentrations of antibiotics from Jining and Peixian were the highest. Antibiotic pollution in different seasons originated from different sources; pollution levels were determined by water levels and rainfall as well as complicated runoff generation and confluence mechanisms. Based on the risk quotients, ofloxacin, sulfamethoxazole and sulfadiazine were identified as the main antibiotics that contributed to high ecological risks. Algae and aquatic plants were the main model organisms exposed to these risks. This study has great significance for environmental prevention and the control of antibiotic contamination in Nansi Lake, which is an important water transport channel and the main impounded lake for the eastern route of the south-to-north water diversion project.


Assuntos
Antibacterianos/análise , Monitoramento Ambiental/métodos , Lagos/química , Rios/química , Poluentes Químicos da Água/análise , China , Modelos Lineares , Análise de Componente Principal , Estações do Ano
3.
Chemosphere ; 239: 124642, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31521936

RESUMO

The occurrence of 24 pharmaceuticals (including 15 antibiotics, three analgesic/anti-inflammatory drugs, three anti-epileptic/antidepressant drugs, two beta blockers, and one lipid regulator) was investigated in 75 water samples collected from four bays in the Ugandan part of Lake Victoria. In addition, the potential environmental risk of the target pharmaceutical compounds to aquatic organisms in the aquatic ecosystem of Lake Victoria was assessed. Water samples were extracted using solid phase extraction and analyzed for pharmaceuticals using high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (LC/MS/MS). Eighteen of the 24 pharmaceuticals occurred at quantifiable concentrations. Sulfamethoxazole (1-5600 ng L-1), trimethoprim (1-89 ng L-1), tetracycline (3-70 ng L-1), sulfacetamide (1-13 ng L-1), and ibuprofen (6-780 ng L-1) occurred at quantifiable concentrations in all water samples. Sulfamethazine (2-50 ng L-1), erythromycin (10-66 ng L-1), diclofenac (2-160 ng L-1), and carbamazepine (5-72 ng L-1) were only quantifiable in water samples from Murchison Bay. The highest concentrations of pharmaceuticals were found in Murchison Bay, the main recipient of sewage effluents, industrial and municipal waste from Kampala city via the Nakivubo channel. Ecotoxicological risk assessment showed that sulfamethoxazole, oxytetracycline, erythromycin, and diclofenac pose a high toxic risk to aquatic organisms in the lake, while ciprofloxacin, norfloxacin, and ibuprofen pose a medium risk. This study is the first of its kind to report the levels and ecotoxic risks of pharmaceutical compounds in Lake Victoria waters, of Uganda, and East Africa as a whole.


Assuntos
Monitoramento Ambiental/métodos , Lagos/química , Preparações Farmacêuticas/análise , Esgotos/química , Poluentes Químicos da Água/análise , Antagonistas Adrenérgicos beta/análise , Antibacterianos/análise , Anti-Inflamatórios não Esteroides/análise , Organismos Aquáticos/efeitos dos fármacos , Cromatografia Líquida , Cidades , Diclofenaco/análise , Ecossistema , Ecotoxicologia , Medição de Risco , Extração em Fase Sólida , Espectrometria de Massas em Tandem , Uganda
4.
Sci Total Environ ; 699: 134301, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31525544

RESUMO

The concentration, source and composition of dissolved organic matter (DOM) in aquatic ecosystems are associated with land use and hydrological connectivity between terrestrial and aquatic systems. However, direct evidence of the effects of rainfall and land use on the variability of DOM in aquatic ecosystems is very limited. In this study, chromophoric DOM (CDOM) absorption and fluorescence spectroscopy were used to elucidate how rainfall and land use affect the variability of CDOM in the watershed of Lake Tianmu, a key drinking water reservoir in the Yangtze River Delta. The mean values of the fluorescence intensity (Fmax) of parallel factor analysis-derived humic-like components (C1, C3, C6) and tryptophan-like components C5 were higher in the southeastern inflowing river mouths than those downstream of the lake outlet regions. The upstream tributaries were mainly dominated by humic-like materials, while the lake was mainly dominated by protein-like materials. The Fmax values of four humic-like components and two tryptophan-like components all increased significantly as the %woodland decreased, but %anthropogenic land use (%cropland+%urban construction area) increased. The Fmax of the humic-like components at the inflowing tributaries and the lake increased with increasing rainfall during storm events, and the value was especially pronounced at the inflowing river mouths. We concluded that land use and hydrological conditions play an important role in influencing the CDOM source and optical composition, and these findings provide insights for the understanding of aquatic ecosystem metabolism and reservoir water quality management.


Assuntos
Água Potável/química , Monitoramento Ambiental/métodos , Poluição da Água/análise , China , Ecossistema , Análise Fatorial , Fluorescência , Lagos/química , Chuva , Rios , Estações do Ano , Espectrometria de Fluorescência , Poluição da Água/estatística & dados numéricos , Qualidade da Água
5.
Huan Jing Ke Xue ; 41(1): 224-231, 2020 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854923

RESUMO

In this paper, nutrient elements (N and P), heavy metals (Pb, Cu, Zn, Cd, Cr, Co, Ni, and Sn), and grain size in surface sediments of Baiyangdian Lake, northern China, are studied. We also analyze the spatial variation in elemental characteristics and undertaken a pollution risk assessment. By combining data with information on the river sediment characteristics, we use multivariate statistical methods to reveal the sources and variation of elements in sediments. The results showed that the average contents of heavy metals in surface sediments from the lake and associated rivers were higher than background values. Within the area of the lake, nutrient elements are relatively high in the northwest region but low in the southeast region, and heavy metals are relatively high in the middle of the lake but low in the southern and northern areas. The sequence of comprehensive pollution index (I) in sediments was Cd > Pb > Cr > Cu=Zn > Ni > Sn > Co, with Cd being assessed as severe pollution and other elements as moderate pollution, although severe pollution of Cr was found in the Zaolinzhuang area. The order of potential ecological risk coefficients (Eri) was determined as Cd > Pb > Cu > Cr > Ni > Zn, whereby Cd was associated with a strong potential ecological risk (except in the Caiputai area) and other elements were associated with a slight potential ecological risk. Differences in the lake sediment texture were found to be slight. Non-point source pollution after rivers flow into the lake was determined as the main reason for the spatial variation of elements in the surface sediments of Baiyangdian Lake, although point source pollution in the villages surrounding the lake should not be ignored, especially with respect to N, P, Pb, and Cr.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Lagos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , China , Medição de Risco , Rios/química
6.
Chemosphere ; 240: 124938, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574444

RESUMO

Clearwater Mesa (James Ross Island, northeast Antarctic Peninsula) provides a unique opportunity to study solute dynamics and geochemical weathering in the pristine lacustrine systems of a high latitude environment. In order to determine major controls on the solute composition of these habitats, a geochemical survey was conducted on 35 lakes. Differences between lakes were observed based on measured physico-chemical parameters, revealing neutral to alkaline waters with total dissolved solids (TDS) < 2500 mg L-1. Katerina and Trinidad-Tatana systems showed an increase in their respective TDS, total organic carbon values, and finner sediments from external to internal lakes, indicating an accumulation of solutes due to weathering. Norma and Florencia systems exhibited the most diluted and circumneutral waters, likely from the influence of glacier and snow melt. Finally, isolated lakes presented large variability in TDS values, indicating weathering and meltwater contributions at different proportions. Trace metal abundances revealed a volcanic mineral weathering source, except for Pb and Zn, which could potentially indicate atmospheric inputs. Geochemical modelling was also conducted on a subset of connected lakes to gain greater insight into processes determining solute composition, resulting in the weathering of salts, carbonates and silicates with the corresponding generation of clays. We found CO2 consumption accounted for 20-30% of the total species involved in weathering reactions. These observations allow insights into naturally occurring geochemical processes in a pristine environment, while also providing baseline data for future research assessing the impacts of anthropogenic pollution and the effects of climate change.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Lagos/química , Minerais/análise , Compostos Orgânicos/análise , Oligoelementos/análise , Regiões Antárticas , Carbonatos/análise , Mudança Climática , Ecossistema , Camada de Gelo/química , Chumbo/análise , Trinidad e Tobago , Tempo (Meteorologia) , Zinco/análise
7.
Chemosphere ; 238: 124674, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524614

RESUMO

Groundwater discharge from a water spring located along the southwest bank of Yangzonghai Lake, the largest deep plateau-lake with arsenic contamination in a typical karst landform, maybe a potential and on-going source of pollution, but seepage flux has not been investigated. This study applied temperature models to locate sites of groundwater discharge and quantify the magnitude and direction of seepage flux. The contaminant levels and spatial distributions, seasonal seepage flux distributions and the conductivity were investigated. The arsenic concentration of the water spring was 1481.9 µg L-1, and as the distance from the water spring increased, the arsenic concentration in the overlying water, pore-water and surface sediments decreased. Herein, the temperature models of McCallum and Bredehoeft were applied to estimate the lakebed vertical seepage flux in groundwater-surface water exchange systems during a period of 30-day in summer and winter. An upward flow of groundwater discharge was observed near the water spring, with the value of some sites over 10 cm day-1, and a downward flow was observed with increasing distance from the water spring in summer. Additionally, a slight upward flow was observed in winter. The arsenic levels, spatial distributions and the conductivity in monitoring sites were closely related to the seepage flux. The application provided a scientific basis for the prediction of groundwater-surface water exchange in deep plateau-lake and was a further development in temperature models.


Assuntos
Água Subterrânea/química , Temperatura Ambiente , Movimentos da Água , Arsênico/análise , China , Monitoramento Ambiental , Lagos/química , Estações do Ano , Poluentes Químicos da Água/análise
8.
Chemosphere ; 240: 124879, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31568947

RESUMO

Heavy metals which pollute aquatic environments typically bond with bottom sediments and the analysis of the spatial distribution of metals allows to assess the geochemical purity of deposits and to identify the potential pollution sources. Research carried out on the Wigry Lake involved the collection of almost 500 samples of sediments, and the specification of the depth of their residence (0.2-71.4 m) as well as the level of concentration of three metals: Fe (80.3-32 857 mg kg-1), Mn (17.8-1698 mg kg-1) and Zn (3.14-632 mg kg-1). The geochemical and bathymetric data was interpolated using geostatistical methods and mapped with the consideration of 5 types of sediments: lacustrine chalk, carbonate gyttja, fluvial-lacustrine sediment, organic gyttja and clastic sediment. As a result, a significant increase in the concentration of metals was revealed in deeper zones, at a considerable distance from the lake shore, wherein the respective values of correlation coefficients were as follows: depth-Mn 0.77; depth-Fe 0.60; depth-Zn 0.58. A strong dependency between the concentration of analysed metals and the type of sediment, attributed to the granular and chemical composition of sediments, was also revealed. Correlations between individual metallic pairs (Fe-Mn 0.77; Fe-Zn 0.80; Mn-Zn 0.75) indicated that similar factors influence spatial distribution of metals in sediments. The implementation of 3 different geochemical backgrounds allowed to conclude that the Wigry Lake is slightly polluted with the analysed metals, and that the origin of Mn is mainly natural, while in the case of Fe and Zn anthropogenic influence can also be identified.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/análise , Lagos/química , Metais Pesados/análise , Poluentes Químicos da Água/análise , Polônia
9.
Sci Total Environ ; 701: 135021, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31734487

RESUMO

This study assess the presence of pharmaceutical and personal care products (PPCPs) and pesticides in different environmental compartments and microplastics in water of a characteristic lagoon wetland in Saudi Arabia to establish the transport, accumulation and fate of these pollutants in a water-stressed area under high anthropogenic pressure. In water, diazinon (up to 1016 ng L-1), caffeine (up to 20,663 ng L-1), diclofenac (up to 1390 ng L-1) and paracetamol (up to 3069 ng L-1) were at the highest concentrations. The substances with the highest frequency of detection were carbendazim, atorvastatin, caffeine, etoricoxib, lorazepam, metformin, ofloxacin, paracetamol, salicylic acid and tramadol. Considerably less pesticides and PPCPs at concentrations ranging from 0.01 to 126 ng g-1 dry weight (d.w.) were detected in the other matrices (sediment ≫ soil > plants). The concentration of microplastics in water ranged from 0.7 to 7.8 items/L in the Al-Asfar lake and from 1.1 to 9.0 items/L in the Al-Hubail lake. Risk assessment [using hazards quotients (HQ)] was used to highlight pesticides and PPCPs of major ecological concern that should be closely monitored to avoid adverse effects.


Assuntos
Monitoramento Ambiental , Lagos/química , Poluentes Químicos da Água/análise , Cosméticos/análise , Praguicidas/análise , Preparações Farmacêuticas/análise , Arábia Saudita
10.
Chemosphere ; 240: 124903, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563100

RESUMO

Excessive nitrogen has been a global concern to cause lake eutrophication. The denitrification and anammox processes are considered to be effective biological pathways for nitrogen removal. Submerged macrophytes also play a key role in the nitrogen cycle of lakes. However, the mechanism of submerged macrophytes on regulating biological nitrogen removal pathways has not been well quantified. Therefore, this study investigated the impacts of submerged macrophytes on the community structures and abundance of the nirS-type denitrifiers and anammox bacteria in the rhizospheres. The qPCR results indicated that the abundance of two bacteria in the near-rhizospheres of submerged macrophytes was significantly lower than the root compartments and non-rhizospheres, while the concentrations of organic acids in the near-rhizospheres were higher than those of the root compartments and non-rhizospheres. Redundancy analysis results illustrated that concentrations of NO3--N, NO2--N, citric acid and oxalic acid were the key environmental indicators which had the significant impact on the microbial community. The concentrations of citric acid and oxalic acid were negatively correlated with the nirS-type denitrifiers abundance, and the oxalic acid concentrations were negatively correlated with the anammox bacteria abundance. These results indicated that submerged macrophytes could reduce the abundance of nirS-type denitrifiers and anammox bacteria by releasing organic acids. In addition, the highest diversity of denitrifier community were found in the rhizosphere of the Hydrilla verticillata, while the highest diversity of anammox community were found in the Potamogeton maackianus rhizosphere. These results indicate that the impacts of submerged macrophytes on the biological nitrogen removal pathways were species-dependent.


Assuntos
Biodegradação Ambiental , Desnitrificação/genética , Rizosfera , Microbiologia do Solo , Bactérias/metabolismo , Eutrofização , Hydrocharitaceae/metabolismo , Lagos/química , Nitrogênio/química , Ciclo do Nitrogênio , Compostos Orgânicos/metabolismo , Potamogetonaceae/microbiologia
11.
J Environ Sci (China) ; 87: 260-271, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791499

RESUMO

An embedded reservoir that provides an efficient nutrient removal system protects drinking water. However, embedded reservoirs are rarely used in eutrophic shallow lakes because of their undetermined nutrient retention efficiency and unknown effects by the phytoplankton community. In this study, we aim to investigate the nutrient retention and algae succession in an embedded reservoir and adjacent wetland from April 2017 to September 2018 in the eastern part of Lake Taihu, China. More than 40% of total phosphorus (TP) and 45% of particulate phosphorous entering the reservoir were retained semi-annually, and the highest TP removal efficiency was achieved in the reservoir during autumn with an average value of 53.3% ±â€¯9.9%. The overall nitrogen retention efficiency (21.7% ±â€¯37.8%) was lower than that of TP (41.8% ±â€¯27.8%). Similar trends were obtained in the wetland area. An important pathway for phosphorus removal is through particulate matter retention. Our study revealed that nutrient retention mechanisms in the reservoir were primarily via macrophyte absorption, particulate substance sedimentation, and prolonged water residence time. Consequently, the phytoplankton biomass (Chl-a) in the reservoir decreased (from 48.0 to 25.2 µg/L) and water transparency improved, due to the decreased P level and transformation of the phytoplankton group into simple structures with good ecological status. Therefore, the combination of embedded reservoir and constructed wetland ecosystem can be used successfully to protect surface water. The results will be advantageous to groups seeking to preserve drinking water sources.


Assuntos
Água Potável , Monitoramento Ambiental , Áreas Alagadas , Biodegradação Ambiental , China , Ecossistema , Lagos/química , Nitrogênio/análise , Fósforo/análise , Fitoplâncton
12.
Chemosphere ; 239: 124685, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31521928

RESUMO

This review provides a summary of the levels and profiles of PCDD/Fs throughout China, as reported in peer reviewed literatures since 1997. The literature shows that PCDD/Fs are widespread in various environmental media including air, water, sediment, and soil. PCDD/Fs concentrations in air were relatively low in most regions, with only a few areas considered polluted. Many studies reported seasonal trends, with higher and lower concentrations in winter and summer, respectively. We analyzed the factors affecting the concentrations of dioxins in air and summarized the causes of seasonal changes. As hydrophobic organic compounds, PCDD/Fs readily accumulate in sediments. The distribution of dioxins in sediment in Bohai Sea area was mainly introduced and the factors affecting concentrations of dioxins were studied. The levels of dioxins in soil in different regions varied greatly, with higher levels in areas close to pollution sources. We examined the dioxins concentrations in soil in places where the levels were very low (including the Tibet Plateau and other remote areas), contaminated areas, and other areas. Apart from the contaminated areas, the dioxins concentrations in soil were low. The results of the relatively low number of studies that have investigated PCDD/Fs in water have reported no obvious pollution in some waters, apart from Dongting Lake. PCDD/Fs levels across China are similar to those worldwide. Point sources, mainly related to local geographic, economic, and historical factors, were the most common source of contamination. E-waste dismantling and chemical production has the greatest impact on PCDD/Fs in different media.


Assuntos
Dibenzofuranos Policlorados/análise , Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Dibenzodioxinas Policloradas/análise , Poluentes Químicos da Água/análise , China , Sedimentos Geológicos/química , Lagos/química , Solo/química , Tibet
13.
Chemosphere ; 238: 124569, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31442777

RESUMO

Point pollution sources may differently impact lakes littoral, possibly leading to local ecological risks. The concomitant chemical analysis of littoral-benthic organisms and sediment can provide insights into the bioavailability and thus the ecological risk of contaminants. In this study, the autochthonous Corbicula fluminea was used to assess the sources and transfer of six trace metals (TMs) and fourteen Polycyclic Aromatic Hydrocarbons (PAHs) to the littoral-benthic biota of a large lake. The contaminant concentrations spatially varied with a value scale from 1 to 280 000 times along the lake littoral in both the sediment and clams. Multiple linear regressions were performed to explain the spatial variability of Corbicula fluminea contamination by considering both watershed and in-lake sources. The concentration of the sum of PAHs in clams was significantly correlated with sediment contamination, suggesting that PAHs contamination of the benthic biota mainly occur from the sediment. Most of the internal TM concentrations of clams were significantly correlated with stormwater drainage areas in the lake watershed, highlighting the importance of stormwater runoffs in the littoral biota contamination. The transfer of TMs and PAHs was assessed through the bioconcentration factor defined as the ratio of internal and sediment concentrations. As, Cd, Cu, Zn and light molecular weight PAHs were more bioconcentrated in C. fluminea than Pb, Sn and heavy molecular weight PAHs, suggesting differences in their bioavailability. This study underlines the relevance of using autochthonous organisms as bioindicators of lake littoral biota contamination concomitantly with sediment matrices, and illustrates the challenge of tracking pollution sources in lakes.


Assuntos
Corbicula/química , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Oligoelementos/análise , Poluentes Químicos da Água/análise , Animais , Biota , Biomarcadores Ambientais , Lagos/química , Metais Pesados/análise , Alimentos Marinhos/análise
14.
Chemosphere ; 239: 124774, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31521937

RESUMO

Acid mine drainage represents an extreme type of water pollution. The environments develop especial hydrochemical and ecological characteristics, such as high concentrations of acidity and low biodiversity, with dominance of acidophilic organisms. Ecological criteria are assuming increasing relevance for assessing water quality, including in acid mine drainage-affected systems. Photosynthetic pigments, like chlorophyll, could be considered in this context as they are generally used to estimate phytoplankton biomass. The present work was focused on acid mine drainage and their relationships with chlorophyll a. It was developed in the historic mine of São Domingos (Iberian Pyrite Belt, SW Europe). The methodological approach comprised two sampling campaigns (October and February) to represent seasonal behaviour. The diversity of hydrological conditions was also considered through sampling sites established in the pit lake, acidic lagoons and affected stream. Hydrochemistry and chlorophyll a were analysed. The obtained results revealed very low pH values, with a minimum of 2.1. In general, hydrochemistry indicates higher concentrations of pollutants in summer. One of the sampling point, located in an acidic lagoon, stood out by highest concentrations, presenting maximum of sulfate (6564 mg/L), As (6.26 mg/L), and metals like Al (675 mg/L), Cd (1,30 mg/L), Zn (199 mg/L). These highest concentrations coincided with the maximum concentration of chlorophyll a (113 µg/L). The results suggested that the more contaminated the environment, more chlorophyll a was produced. Factor analyses emphasised the relationships between acid drainage properties and the photosynthetic activity, indicating a strong pH dependency of chlorophyll a production.


Assuntos
Clorofila A/análise , Mineração , Poluição da Água/análise , Biomassa , Monitoramento Ambiental , Europa (Continente) , Lagos/química , Metais/análise , Feofitinas/análise , Fotossíntese , Fitoplâncton , Rios/química , Estações do Ano , Sulfatos/análise , Poluentes Químicos da Água/análise , Qualidade da Água
15.
Talanta ; 206: 120202, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514885

RESUMO

Tetracycline (TC), a widely-used antibiotic to treat bacterial infections, combines with Eu3+ to form a stable EuTC complex that has a low fluorescence (FL) yield because of Eu3+ coordination with water molecules. We report a simple, label-free ratiometric fluorescent platform for sensitively and selectively sensing of TC, using L-histidine caped gold nanoclusters (His-AuNCs) as a FL indicator and an enhancer of Eu3+ FL. The His-AuNCs were prepared via chemical reduction of Au(III) by L-histidine, which was a reducer and a protecting agent. The His-AuNCs exhibited good photostability, outstanding stability toward high ionic strengths, storage stability, and favorable optical properties. In the absence of TC, the AuNCs-Eu3+ system displays strong FL emission at 475 nm (F475) from the His-AuNCs and weak FL at 620 nm from Eu3+ (F620) with excitation at 375 nm. TC quenches the His-AuNC FL and greatly enhances the Eu3+ emission. This is attributed to an enhancement of the EuTC complex fluorescence by the His-AuNCs. Thus, a ratiometric F620/F475 FL signal can be used for TC detection by simply mixing AuNCs and Eu3+. Under the optimized conditions, the linear range from 10 nM to 60 µM and a detection limit of 4 nM (S/N = 3) for TC were obtained. The application of the assay platform for the detection of TC in environmental and biological samples was demonstrated. The sensing platform has advantages of easy preparation, rapid response, high sensitivity, and good selectivity.


Assuntos
Európio/química , Corantes Fluorescentes/química , Ouro/química , Nanopartículas Metálicas/química , Tetraciclina/sangue , Antibacterianos/sangue , Antibacterianos/química , Complexos de Coordenação/química , Fluorescência , Histidina/química , Lagos/análise , Lagos/química , Limite de Detecção , Espectrometria de Fluorescência/métodos , Tetraciclina/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
16.
Sci Total Environ ; 698: 134328, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31783469

RESUMO

In eutrophic lacustrine ecosystems, drifting algal blooms are easily trapped by emergent macrophytes in downwind littoral zones, potentially altering carbon cycling processes; yet, knowledge remains limited about the mechanisms driving these changes. In this study, Microcystis and Phragmites, two dominant photosynthetic organisms in a hypereutrophic (Lake Taihu, China), were collected to simulate their co-decomposition processes. We demonstrate how molecular-level biomarkers could be used to elucidate the degradation dynamics of these two distinct organic forms in mixtures. Microcystis-derived carbon accelerated the decomposition rate of mixed systems (positive co-metabolism effect), rather than retarding it. The decomposition rate of TOC (total organic carbon) directly measured in the mixed treatments was 14% higher than when the two substrates were incubated alone. The use of specific fatty acid biomarkers facilitated more accurate tracking, demonstrating 1.09 times higher decomposition rates for Phragmites detritus in mixed treatments than in single Phragmites treatments. Furthermore, Microcystis showed 0.98 times higher decomposition rates in mixed treatments than in single treatments. The addition of Microcystis detritus to Phragmites detritus might meet microbial stoichiometric requirements, increasing the abundance of decomposing bacteria in Phragmites detritus, and accelerating decomposition rates, resulting in the co-metabolism of Microcystis and Phragmites carbon. Given the increasing occurrence of algal blooms in eutrophic lakes, the processes documented here might enhance greenhouse gas emissions from lakes with continued global climate warming.


Assuntos
Monitoramento Ambiental , Lagos/química , Poluentes da Água/análise , Biomarcadores , China , Ecossistema , Eutrofização , Sedimentos Geológicos , Microcystis
17.
Ecotoxicol Environ Saf ; 188: 109888, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31706242

RESUMO

Eutrophication can induce hypoxia/anoxia and rich organic matter at the sediment-water interface in surface waters. When eutrophic waters are impacted with mercury (Hg) pollution, methylmercury (MeHg) production ability (MPA) of surface sediment would increase and more MeHg might be produced. To tackle this risk, this study firstly collected samples of surface sediment and overlying water from a typical eutrophic lake-Taihu Lake. Then from a sediment-water simulation system, we demonstrated that eutrophic waters were able to methylate Hg spontaneously, and that sediment is the major Hg sink in the system. After the addition of HgCl2 solution (approximately 1 mg L-1 in the slurry), MeHg concentrations in the sediment increased by 11.7 times after 48 h. The subsequent column experiments proved that O2 nanobubbles could significantly decrease the MPA of surface sediment, by up to 48%. Furthermore, we found that O2 nanobubbles could remediate anoxia mainly by increasing dissolved oxygen (from 0 to 2.1 mg L-1), oxidation-reduction potentials (by 37% on average), and sulfate (by 31% on average) in the overlying water. In addition, O2 nanobubbles could also help decrease organic matter concentration, as was revealed by the decline of dissolved organic carbon in the overlying water (by up to 57%) and total organic carbon in surface sediment (by up to 37%). The remediation of anoxia and reduction of organic matter could contribute to the decrease of hgcA gene abundance (by up to 86%), and thus result in the reduction of MPA after the addition of O2 nanobubbles. This study revealed the risk of MeHg production in case Hg pollution occurs in eutrophic waters and proposed a feasible solution for MeHg remediation.


Assuntos
Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Compostos de Metilmercúrio/química , Oxigênio/química , Poluentes Químicos da Água/química , Eutrofização , Lagos/química , Mercúrio/análise , Mercúrio/química , Compostos de Metilmercúrio/análise , Compostos Orgânicos/análise , Compostos Orgânicos/química , Oxirredução , Oxigênio/análise , Poluentes Químicos da Água/análise
18.
Zhonghua Yu Fang Yi Xue Za Zhi ; 53(12): 1236-1241, 2019 Dec 06.
Artigo em Chinês | MEDLINE | ID: mdl-31795579

RESUMO

Objective: To investigate the content of persistent organic pollutants (POPs) in fish from Dongting Lake. Methods: Ten sample collection points were set in lakeside city Yueyang and Yuanjiang. In July (wet season) and November (dry season) of 2012, 13 common fish species were captured by convenience sampling in Dongting Lake. Two to three fish with similar weight were selected in each season for the same species of fish. After sample preparation and pretreatment, the contents of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), indicator polychlorinated biphenyls and polybrominated diphenyls ether (PBDEs) in the samples were determined by high resolution gas chromatographer-high resolution mass spectrometry. Toxicity Equivalents (TEQ) of PCDD/Fs and dl-PCBs were calculated according to the revised toxicity equivalent factor (TEF) of WHO in 2005. The contents of POPs were expressed by median and quavtile. The differences of POPs in fish in different periods were compared by Wilcoxon rank sum test. Results: The content of PCDD/Fs of fish in Dongting Lake in wet season was 12.397 (8.865, 24.964) pg/g, higher than that in the dry season 0.771 (0.490, 1.442) pg/g (P<0.001), and the toxicity equivalent quantity (TEQ) were 0.150 (0.066,0.528) and 0.143 (0.066, 0.235) pg-TEQ/g without statistically significant difference (P>0.05). For the fish in wet and dry season from Dongting Lake,Σdl-PCBs of fish were 66.475 (28.065, 77.794) and 24.205 (18.237, 90.777) pg/g, respectively, and the TEQ were 0.061 (0.046, 0.268) and 0.075 (0.054, 0.182) pg-TEQ/g; Σ indicative PCBs were 237.764 (153.896, 335.483) and 119.711 (52.171, 408.696) pg/g, respectively; Σ PBDEs were 106.513 (64.834, 164.860) and 86.837 (61.872, 177.108) pg/g, respectively. The highest content of PCDD/Fs was found in grass carp (198.360 pg/g) in wet season. The higher content of PCBs was found in long-necked fish (2 332.509 pg/g) and PBDEs was found in pelteobagrus fulvidraco (343.857 pg/g), respectively. Conclusion: A lower burden was found in fishes from Dongting Lake, and the content of POPs varied in different seasons and fishes.


Assuntos
Poluentes Ambientais , Peixes/metabolismo , Lagos/análise , Espectrometria de Massas/métodos , Dibenzodioxinas Policloradas/análise , Poluentes Químicos da Água/análise , Animais , Benzofuranos , China , Dibenzofuranos , Dibenzofuranos Policlorados , Lagos/química , Bifenilos Policlorados , Dibenzodioxinas Policloradas/efeitos adversos , Dibenzodioxinas Policloradas/metabolismo , Poluentes Químicos da Água/metabolismo
19.
Environ Monit Assess ; 192(1): 7, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797108

RESUMO

Lake surface water temperature (LSWT) is a key indicator which drives ecosystem structure and function. Quantifying the impact of climate change on LSWT variations is thus of great significance. In this study, observed data of LSWT during the period 1969-2018 in a high mountain lake (Morskie Oko Lake, Central Europe) were analyzed. The results showed that the prominent warming of the LSWT and air temperature began around 1997. A logistic non-linear S-curve function was used to model monthly average LSWT. The non-linear model performed well to capture monthly average LSWT and air temperature relationships (Nash-Sutcliffe efficiency coefficient 0.86 and the root mean squared error 1.63 °C). Using the 2009-2018 period as base scenario, a sensitivity analysis was conducted. The results showed that the annual mean LSWT will likely increase about + 1.29 °C and + 2.64 °C with air temperature increases of + 2 °C and + 4 °C respectively at the end of the twenty-first century. If realized, such a scenario will cause serious consequences on lake ecosystem.


Assuntos
Mudança Climática , Monitoramento Ambiental , Lagos , Temperatura Ambiente , Ecossistema , Europa (Continente) , Lagos/química
20.
Environ Monit Assess ; 192(1): 5, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797222

RESUMO

Lake Cajititlán is a shallow body of water located in an endorheic basin in western Mexico. This lake receives excess fertilizer runoff from agriculture and approximately 2.3 Hm3 per year of poorly treated wastewater from three municipal treatment plants. Thirteen water quality parameters were monitored at five sampling points within the lake over 9 years. The objective of this work was to characterize the spatial and temporal variations of the water quality and to identify the sources of data variability in order to assess the influence and the impact of different natural and anthropogenic processes. One-way ANOVA tests, principal component analysis (PCA), cluster analysis (CA), and discriminant analysis (DA) were implemented. The one-way ANOVA showed that biochemical oxygen demand and pH present statistically significant spatial variations and that alkalinity, total chloride, conductivity, chemical oxygen demand, total hardness, ammonia, pH, total dissolved solids, and temperature present statistically significant temporal variations. PCA results explained both natural and anthropogenic processes and their relationship with water quality data. The CA results suggested there is no significant spatial variation in the water quality of the lake because of lake mixing caused by wind. The most significant parameters for spatial variations were pH, NO3-, and NO2-, consistent with the configuration of point and nonpoint sources that affect the lake's water quality. The temporal DA results suggested that conductivity, hardness, NO2-, pH, and temperature were the most significant parameters to discriminate between seasons. The temporal behavior of these parameters was associated with the transport pathways of seasonal contaminants.


Assuntos
Monitoramento Ambiental , Lagos/química , Análise Multivariada , Qualidade da Água , Análise por Conglomerados , Análise Discriminante , Monitoramento Ambiental/métodos , México , Análise de Componente Principal , Estações do Ano , Poluentes Químicos da Água/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA