RESUMO
Extensive spatiotemporal analyses of long-trend surface ozone in the Yangtze River Delta (YRD) region and its meteorology-related and emission-related have not been systematically analyzed. In this study, by using 8-year-long (2015-2022) surface ozone observation data, we attempted to reveal the variation of multiple timescale components using the Kolmogorov-Zurbenko filter, and the effects of meteorology and emissions were quantitatively isolated using multiple linear regression with meteorological variables. The results showed that the short-term, seasonal, and long-term components accounted for daily maximum 8-hr average O3 (O3-8 hr) concentration, 46.4%, 45.9%, and 1.0%, respectively. The meteorological impacts account for an average of 71.8% of O3-8 hr, and the YRD's eastern and northern sections are meteorology-sensitive areas. Based on statistical analysis technology with empirical orthogonal function, the contribution of meteorology, local emission, and transport in the long-term component of O3-8 hr were 0.21%, 0.12%, and 0.6%, respectively. The spatiotemporal analysis indicated that a distinct decreasing spatial pattern could be observed from coastal cities towards the northwest, influenced by the monsoon and synoptic conditions. The central urban agglomeration north and south of the YRD was particularly susceptible to local pollution. Among the cities studied, Shanghai, Anqing, and Xuancheng, located at similar latitudes, were significantly impacted by atmospheric transmission-the contribution of Shanghai, the maximum accounting for 3.6%.
Assuntos
Poluentes Atmosféricos , Monitoramento Ambiental , Ozônio , China , Ozônio/análise , Poluentes Atmosféricos/análise , Rios/química , Estações do Ano , Meteorologia , Poluição do Ar/estatística & dados numéricos , Poluição do Ar/análiseRESUMO
Phthalic acid esters (PAEs) are a group of compounds widespread in the environment. To investigate the occurrence and accumulation characteristics of PAEs, surface water samples were collected from the Three Gorges Reservoir area, China. The total concentrations of 11 analyzed PAEs (∑11PAEs) in the collected water samples ranging from 197.7 to 1,409.3 ng/L (mean ± IQR: 583.1 ± 308.4 ng/L). While DEHP was the most frequently detected PAE, DnBP and DnNP were the most predominant PAEs in the analyzed water samples with a mean contribution of 63.3% of the ∑11PAEs. The concentrations of the ∑11PAEs in the water samples from the upper reaches of the Yangtze River were significantly higher than those from the middle reaches. To better understand the transport and fate of the PAEs, seven detected PAEs were modeled by Quantitative Water Air Sediment Interaction (QWASI). The simulated and measured values were close for most PAEs, and differences are within one order of magnitude even for the worst one. For all simulated PAEs, water and particle inflow were main sources in the reservoir, whereas water outflow and degradation in water were important removal pathways. The contribution ratios of different sources/losses varied from PAEs, depending on their properties. The calculated risk quotients of DnNP in the Three Gorges Reservoir area whether based on monitoring or simulating results were all far exceeded the safety threshold value, implying the occurrence of this PAE compound may cause potential adverse effects for the aquatic ecology of the Three Gorges Reservoir area.
Assuntos
Monitoramento Ambiental , Ésteres , Ácidos Ftálicos , Poluentes Químicos da Água , Ácidos Ftálicos/análise , China , Poluentes Químicos da Água/análise , Ésteres/análise , Rios/química , Modelos QuímicosRESUMO
The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers. However, little information is available on how the rainfall affect nutrient dynamics in subtropical montane rivers with complex land use. This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu, a montane reservoir of southeast China. The results showed that riverine total nitrogen (TN) and total phosphorus (TP) concentrations increased continuously with increasing rainfall intensity, while TN:TP decreased. The heavy rainfall and rainstorm drove more than 30% of the annual N and P loading in only 5.20% of the total rainfall period, indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs. NO3--N is the primary nitrogen form lost, while particulate phosphorus (PP) dominated phosphorus loss. The main source of N is cropland, and the main source of P is residential area. Spatially, forested watersheds have better drainage quality, while it is still a potential source of nonpoint pollution during rainfall events. TN and TP concentrations were significantly higher at sites dominated by cropland and residential area, indicating their substantial contributions to deteriorating river water quality. Temporally, TN and TP concentrations reached high values in May-August when rainfall was most intense, while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities. The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads, providing guidance for nutrient load reduction planning for Lake Qiandaohu.
Assuntos
Monitoramento Ambiental , Nitrogênio , Fósforo , Chuva , Rios , Poluentes Químicos da Água , Fósforo/análise , Nitrogênio/análise , China , Rios/química , Poluentes Químicos da Água/análise , AgriculturaRESUMO
Phthalate esters (PAEs), recognized as endocrine disruptors, are released into the environment during usage, thereby exerting adverse ecological effects. This study investigates the occurrence, sources, and risk assessment of PAEs in surface water obtained from 36 sampling points within the Yellow River and Yangtze River basins. The total concentration of PAEs in the Yellow River spans from 124.5 to 836.5 ng/L, with Dimethyl phthalate (DMP) (75.4 ± 102.7 ng/L) and Diisobutyl phthalate (DiBP) (263.4 ± 103.1 ng/L) emerging as the predominant types. Concentrations exhibit a pattern of upstream (512.9 ± 202.1 ng/L) > midstream (344.5 ± 135.3 ng/L) > downstream (177.8 ± 46.7 ng/L). In the Yangtze River, the total concentration ranges from 81.9 to 441.6 ng/L, with DMP (46.1 ± 23.4 ng/L), Diethyl phthalate (DEP) (93.3 ± 45.2 ng/L), and DiBP (174.2 ± 67.6 ng/L) as the primary components. Concentration levels follow a midstream (324.8 ± 107.3 ng/L) > upstream (200.8 ± 51.8 ng/L) > downstream (165.8 ± 71.6 ng/L) pattern. Attention should be directed towards the moderate ecological risks of DiBP in the upstream of HH, and both the upstream and midstream of CJ need consideration for the moderate ecological risks associated with Di-n-octyl phthalate (DNOP). Conversely, in other regions, the associated risk with PAEs is either low or negligible. The main source of PAEs in Yellow River is attributed to the release of construction land, while in the Yangtze River Basin, it stems from the accumulation of pollutants in lakes and forests discharged into the river. These findings are instrumental for pinpointing sources of PAEs pollution and formulating control strategies in the Yellow and Yangtze Rivers, providing valuable insights for global PAEs research in other major rivers.
Assuntos
Monitoramento Ambiental , Ésteres , Ácidos Ftálicos , Rios , Poluentes Químicos da Água , Ácidos Ftálicos/análise , Rios/química , China , Poluentes Químicos da Água/análise , Medição de Risco , Ésteres/análise , Disruptores Endócrinos/análise , Dibutilftalato/análise , Dibutilftalato/análogos & derivadosRESUMO
China's lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus (P) from anthropogenic activities. However, quantifying P dynamics in a lowland rural river is challenging due to its complex interaction with surrounding areas. A P dynamic model (River-P) was specifically designed for lowland rural rivers to address this challenge. This model was coupled with the Environmental Fluid Dynamics Code (EFDC) and the Phosphorus Dynamic Model for lowland Polder systems (PDP) to characterize P dynamics under the impact of dredging in a lowland rural river. Based on a two-year (2020-2021) dataset from a representative lowland rural river in the Lake Taihu Basin, China, the coupled model was calibrated and achieved a model performance (R2>0.59, RMSE<0.04 mg/L) for total P (TP) concentrations. Our research in the study river revealed that (1) the time scale for the effectiveness of sediment dredging for P control was â¼300 days, with an increase in P retention capacity by 74.8 kg/year and a decrease in TP concentrations of 23% after dredging. (2) Dredging significantly reduced P release from sediment by 98%, while increased P resuspension and settling capacities by 16% and 46%, respectively. (3) The sediment-water interface (SWI) plays a critical role in P transfer within the river, as resuspension accounts for 16% of TP imports, and settling accounts for 47% of TP exports. Given the large P retention capacity of lowland rural rivers, drainage ditches and ponds with macrophytes are promising approaches to enhance P retention capacity. Our study provides valuable insights for local environmental departments, allowing a comprehensive understanding of P dynamics in lowland rural rivers. This enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures.
Assuntos
Monitoramento Ambiental , Sedimentos Geológicos , Fósforo , Rios , Poluentes Químicos da Água , Fósforo/análise , Rios/química , Sedimentos Geológicos/química , China , Poluentes Químicos da Água/análise , EutrofizaçãoRESUMO
With the increasing severity of arsenic (As) pollution, quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies. Taking the industrial-intensive Jinsha River Basin as typical area, a two-dimensional hydrodynamic water quality model coupled with Soil and Water Assessment Tool (SWAT) model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution. The effects of hydro-climate change, hydropower station construction and non-point source emissions on As were quantified based on the coupled model. The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream. Due to the enhanced rainfall, the As concentration was significantly higher during the rainy season than the dry season. Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration, but also affected the adsorption and desorption of As in sediment. Furthermore, As concentration increased with the input of non-point source pollution, with the maximum increase about 30%, resulting that non-point sources contributed important pollutant impacts to waterways. The coupled model used in pollutant behavior analysis is general with high potential application to predict and mitigate water pollution.
Assuntos
Arsênio , Monitoramento Ambiental , Rios , Poluentes Químicos da Água , Arsênio/análise , China , Poluentes Químicos da Água/análise , Rios/química , Monitoramento Ambiental/métodos , Modelos Químicos , Modelos TeóricosRESUMO
Tuojiang River Basin is a first-class tributary of the upper reaches of the Yangtze River-which is the longest river in China. As phytoplankton are sensitive indicators of trophic changes in water bodies, characterizing phytoplankton communities and their growth influencing factors in polluted urban rivers can provide new ideas for pollution control. Here, we used direct microscopic count and environmental DNA (eDNA) metabarcoding methods to investigate phytoplankton community structure in Tuojiang River Basin (Chengdu, Sichuan Province, China). The association between phytoplankton community structure and water environmental factors was evaluated by Mantel analysis. Additional environmental monitoring data were used to pinpoint major factors that influenced phytoplankton growth based on structural equation modeling. At the phylum level, the dominant phytoplankton taxa identified by the conventional microscopic method mainly belonged to Bacillariophyta, Chlorophyta, and Cyanophyta, in contrast with Chlorophyta, Dinophyceae, and Bacillariophyta identified by eDNA metabarcoding. In α-diversity analysis, eDNA metabarcoding detected greater species diversity and achieved higher precision than the microscopic method. Phytoplankton growth was largely limited by phosphorus based on the nitrogen-to-phosphorus ratios > 16:1 in all water samples. Redundancy analysis and structural equation modeling also confirmed that the nitrogen-to-phosphorus ratio was the principal factor influencing phytoplankton growth. The results could be useful for implementing comprehensive management of the river basin environment. It is recommended to control the discharge of point- and surface-source pollutants and the concentration of dissolved oxygen in areas with excessive nutrients (e.g., Jianyang-Ziyang). Algae monitoring techniques and removal strategies should be improved in 201 Hospital, Hongrihe Bridge and Colmar Town areas.
Assuntos
Monitoramento Ambiental , Fitoplâncton , Rios , Rios/química , China , Poluentes Químicos da Água/análise , Fósforo/análiseRESUMO
This study focuses on the spatiotemporal distribution, urban-rural variations, and driving factors of ammonia Vertical Column Densities (VCDs) in China's Yangtze River Delta region (YRD) from 2008 to 2020. Utilizing data from the Infrared Atmospheric Sounding Interferometer (IASI), Generalized Additive Models (GAM), and the GEOS-Chem chemical transport model, we observed a significant increase of NH3 VCDs in the YRD between 2014 and 2020. The spatial distribution analysis revealed higher NH3 concentrations in the northern part of the YRD region, primarily due to lower precipitation, alkaline soil, and intensive agricultural activities. NH3 VCDs in the YRD region increased significantly (65.18%) from 2008 to 2020. The highest growth rate occurs in the summer, with an annual average growth rate of 7.2% during the period from 2014 to 2020. Agricultural emissions dominated NH3 VCDs during spring and summer, with high concentrations primarily located in the agricultural areas adjacent to densely populated urban zones. Regions within several large urban areas have been discovered to exhibit relatively stable variations in NH3 VCDs. The rise in NH3 VCDs within the YRD region was primarily driven by the reduction of acidic gases like SO2, as emphasized by GAM modeling and sensitivity tests using the GEOS-Chem model. The concentration changes of acidic gases contribute to over 80% of the interannual variations in NH3 VCDs. This emphasizes the crucial role of environmental policies targeting the reduction of these acidic gases. Effective emission control is urgent to mitigate environmental hazards and secondary particulate matter, especially in the northern YRD.
Assuntos
Poluentes Atmosféricos , Amônia , Monitoramento Ambiental , Rios , China , Amônia/análise , Poluentes Atmosféricos/análise , Rios/química , Agricultura , Análise Espaço-Temporal , Estações do AnoRESUMO
The floodplain of the Yellow River is a typical area characterized by redox fluctuations and heavy metal pollution. However, the mobilization behavior of heavy metals in floodplain sediments during redox fluctuations remains poorly understood. In this study, reductive mobilization of Fe and Mn was observed under reducing environments through reduction and dissolution, leading to the subsequent release of adsorbed As. In contrast, the mobilization of U occurred under oxic conditions, as the oxidative state of U(VI) has higher solubility. Furthermore, insignificant effects on the mobilization of Cd, Cu, Pb, and Hg were noticed during redox fluctuations, indicating higher stability of these heavy metals. Additionally, we demonstrated that carbon sources can play a key role in the mobilization of heavy metals in floodplain sediments, amplifying the reductive mobilization of Fe, Mn, As and the oxidative mobilization of U. Our findings contribute to the understanding of the biogeochemical cycling of heavy metal in floodplain sediments of the Yellow River and the factors that control this cycling.
Assuntos
Monitoramento Ambiental , Sedimentos Geológicos , Metais Pesados , Oxirredução , Rios , Poluentes Químicos da Água , Metais Pesados/análise , Rios/química , Sedimentos Geológicos/química , Poluentes Químicos da Água/análise , ChinaRESUMO
Tetracyclines (TCs) rank second globally in the use of animal infection therapy and animal husbandry as growth promoters among all antibiotics. However, large amounts of TCs residue in food products and more than 75% of TCs are excreted into the environment, causing adverse effects on the ecological system and human health. It has been challenging to simultaneously realize low-cost, rapid, and highly selective detection of TCs. Here, inspired by the fluorogenic reactions between resorcinol and catecholamines, we find the fluorescence quenching ability of tetracycline (TC) and firstly propose a fluorescent "turn-off" detection of TC using dopamine and 4-fluororesorcinol. The optimal reaction condition for the fluorescent assay is investigated and the optimized probe showed a good limit of detection (LOD of 1.7 µM) and a wide linear range (10 µM to 350 µM). Moreover, this fluorescent assay proved to be an effective tool for detecting TC in river, Sprite, and beer samples, which represent the aquatic environments and food and may contain tetracyclines residues. Finally, the high selectivity of the method for TC has been confirmed by eliminating the interference from common substances. The proposed strategy provides a high-efficiency and selective solution for the detection of TCs in environment and food and the application fields of this fluorescent assay could be further expanded in the future.
Assuntos
Tetraciclinas , Tetraciclinas/análise , Espectrometria de Fluorescência/métodos , Limite de Detecção , Cerveja/análise , Corantes Fluorescentes/química , Rios/química , Dopamina/análise , Antibacterianos/análise , Fluorescência , Poluentes Químicos da Água/análise , Contaminação de Alimentos/análiseRESUMO
Against the backdrop of global warming, the pollutants that were once "temporarily stored" in the permafrost are gradually being released, posing significant impacts on the environment. This has become an internationally focused hot topic. In this study, the contents of 11 elements such as As, Ti, Cd, Cr, Co, Mn, Cu, Pb, Ni, Zn and V in soil samples from 128 sampling points in the freeze-thaw area of the Tuotuo River in the source region of the Yangtze River on the Qinghai-Tibet Plateau were determined to evaluate the possible sources, contamination status and ecological, environmental and health risks of these elements. The mean values of As, Cd, Pb and Zn were higher than the corresponding Tibet soil background values. Among fourteen PTEs, As, Cd and Pb had the highest average values of enrichment factor and pollution index, indicating that freeze-thaw area soils showed moderate enrichment and pollution with As, Cd and Pb. Mean ecological risk factor (ER) of Cd was 109 and other PTEs mean ER values < 40, whereas ecological risk index (RI) values of all PTEs ranged from 59.5 to 880 and mean RI values was 152, indicating moderate ecological risk in study area. Explanatory power q value of total S (TS) content was 0.217 by GeogDetector, indicating TS was the most significant contributing factor to RI. Correlation analysis and PCA analysis showed that Cr, Cu, Ni, Co, Mn, Ti, V were mainly originated from natural sources, Cd, Pb and Zn from traffic activity, As from long-distance migration-freeze-thaw.
Assuntos
Arsênio , Monitoramento Ambiental , Rios , Poluentes do Solo , Poluentes do Solo/análise , Arsênio/análise , Tibet , Rios/química , Medição de Risco , Metais Pesados/análise , Solo/química , ChinaRESUMO
The high frequency of flood occurrences and the uneven distribution of hydrological stations make it difficult to monitor large-scale floods. Emergence of the Gravity Recovery and Climate Experiment (GRACE) satellite system sets up a new era of large-scale flood monitoring without much reliance on in situ hydrological observations. The GRACE-derived flood potential index (FPI) exhibits its ability to monitor major events of 2003, 2004, 2007, and 2008 over the Indo-Gangetic-Brahmaputra Basin (IGBB). Precipitation and soil moisture are the major influencing factors of flood. However, the response of potential flooding to such parameters is little known. Pearson's lag correlation analysis is used to examine the response of the GRACE-based FPI to precipitation and soil moisture over the study region comparing seasonal time series of the variables. Results exhibited a 2-month lagged response of FPI to precipitation in the Upper Gangetic Yamuna Chambal Basin (UGYCB) and the Lower Gangetic Basin (LGB) and 1-month lagged response in the Lower Brahmaputra Basin (LBB). With context to soil moisture, a 1-month lag is observed in the Gangetic basins, and no lag is observed in the LBB. Event wise analysis of the lags portrays slightly varying lags for different events; however, it provides a picture on the interaction between these variables. This study also assesses the agreement between FPI and satellite-based river discharge, i.e. Dartmouth Flood Observatory (DFO) discharge. A good correlation (> 0.60) between the two is observed. Threshold values of FPI are determined for the LBB due to its annual flood frequency. The nearly similar accuracy of threshold FPI, determined using DFO discharge, in monitoring floods and the predictive skill measure of FPI for LBB to the previous studies demonstrates the utility of satellite-based discharge in the quantification of threshold FPI values for different percentile floods.
Assuntos
Monitoramento Ambiental , Inundações , Índia , Monitoramento Ambiental/métodos , Imagens de Satélites , Hidrologia , Solo/química , Rios/químicaRESUMO
Pharmaceuticals and personal care products (PPCPs) monitoring in surface water is crucial to address the escalating threat of antimicrobial resistance and safeguard public health. This study aimed to investigate the occurrence of 21 different PPCPs, including wastewater chemical markers, antibiotics, and parabens in the surface water of Chennai city using Ultra Performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry (UPLC-MS/MS) analysis. It is noteworthy that chemical markers viz., carbamazepine (CBZ) and caffeine (CAF) were detected in all the sites and contributed to more than 95% of the total PPCPs load indicating a significant intrusion of wastewater. Among the antibiotics, fluoroquinolones were dominant in this study. Interestingly, a significant and strong correlation was seen between fluoroquinolones, CBZ and CAF (R2 = 0.880-0.928, p < 0.05), suggesting similarities in their sources. More than 50% of the sites exhibited a risk for antimicrobial resistance (RQAMR) with RQAMR > 1 for ciprofloxacin, indicating a significant public health concern. The ecotoxicological risk assessment of PPCPs showed no risk to any organisms, except for triclosan, which posed a risk to fish and daphnids at one site near an open drain in Buckingham canal.
Assuntos
COVID-19 , Cosméticos , Monitoramento Ambiental , Rios , Poluentes Químicos da Água , Poluentes Químicos da Água/análise , Cosméticos/análise , Rios/química , Preparações Farmacêuticas/análise , Índia , COVID-19/epidemiologia , Humanos , Medição de Risco , Espectrometria de Massas em Tandem , Águas Residuárias/química , Antibacterianos/análise , SARS-CoV-2 , PandemiasRESUMO
The Water Quality Index (WQI) provides comprehensive assessments in river systems; however, its calculation involves numerous water quality parameters, costly in sample collection and laboratory analysis. The study aimed to determine key water parameters and the most reliable models, considering seasonal variations in the water environment, to maximize the precision of WQI prediction by a minimal set of water parameters. Ten statistical or machine learning models were developed to predict the WQI over four seasons using water quality dataset collected in a coastal city adjacent to the Yellow Sea in China, based on which the key water parameters were identified and the variations were assessed by the Seasonal-Trend decomposition procedure based on Loess (STL). Results indicated that model performance generally improved with adding more input variables except Self-Organizing Map (SOM). Tree-based ensemble methods like Extreme Gradient Boosting (XGB) and Random Forest (RF) demonstrated the highest accuracy, particularly in winter. Nutrients (Ammonia Nitrogen (AN) and Total Phosphorus (TP)), Dissolved Oxygen (DO), and turbidity were determined as key water parameters, based on which, the prediction accuracy for Medium and Low grades was perfect while it was over 80% for the Good grade in spring and winter and dropped to around 70% in summer and autumn. Nutrient concentrations were higher at inland stations; however, it worsened at coastal stations, especially in summer. The study underscores the importance of reliable WQI prediction models in water quality assessment, especially when data is limited, which are crucial for managing water resources effectively.
Assuntos
Monitoramento Ambiental , Aprendizado de Máquina , Estações do Ano , Qualidade da Água , Monitoramento Ambiental/métodos , China , Cidades , Poluentes Químicos da Água/análise , Fósforo/análise , Nitrogênio/análise , Poluição Química da Água/estatística & dados numéricos , Rios/químicaRESUMO
Limited research has been conducted on microplastic (MP) contamination in the rivers of Goa. To address this gap, this study examines the levels of MP contamination in the surface water of the Zuari River, Goa. We investigate the abundance, characteristics (size, shape, colour, and polymer composition), and risk assessment of MPs. MPs were detected at all sampling stations in the Zuari River, with concentrations varying from 0.01 particles/L (S3) to 1.38 particles/L (S13). The average abundance of MPs in the water samples was 0.28 ± 0.35 particles/L. MPs were more common in the 0.3-1 mm size range (51.70%) than in the 1-5 mm range (48.30%). The most common MP shapes observed were fibers (37.88%) and fragments (29.66%). FTIR analysis confirmed the presence of polyethylene terephthalate, high-density polyethylene, polypropylene, and polyacrylamide carboxyl-modified MPs. The Pollution Load Index (PLI) showed an average value of 3.8, indicating significant contamination (PLI > 1). Scanning electron microscopy (SEM) revealed various degradation features such as pits, scratches, grooves, and cracks on the MPs surfaces, while energy dispersive X-ray spectroscopy (EDS) detected metals on the MP's surfaces. This study provides key insights into MP pollution in the Zuari River's surface water and lays the groundwork for future research and management strategies in the region.
Assuntos
Monitoramento Ambiental , Microplásticos , Rios , Poluentes Químicos da Água , Índia , Poluentes Químicos da Água/análise , Rios/química , Microplásticos/análise , Poluição Química da Água/estatística & dados numéricosRESUMO
The golden mussel (Limnoperna fortunei) is an invasive bivalve that has established itself in several South American river systems, impacting ecosystem functioning. Reservoir cascades provide their larvae with the means of rapid dispersal, but the relationship between environmental variables and larval stage structure remains unclear. In this study, the density of three L. fortunei larval stages and quantitative detection using DNA are analyzed in a cascade of five reservoirs in the upper Uruguay River Basin and associated with spatiotemporal variation in environmental parameters. The analysis of L. fortunei eDNA presence and absence in freshwater systems appears to be a valuable mapping tool; however, no significant link was found between the eDNA magnitude and the overall larval density. The increase in larval density was related to the fluctuation of environmental parameters over a year, with the highest average larval densities observed in the CN and ITA reservoirs, though no significant difference was observed between the five reservoirs, where D-shaped larvae predominated. During winter, larval density decreased significantly, however, other variables also contribute to species activity and development in the upper Uruguay River Basin reservoirs and may be considered limiting factors. The relationships between environmental parameters were evaluated using a multivariate model. The interaction between reservoir area and precipitation, water temperature, electrical conductivity, and dissolved oxygen had a significant effect on larval density but showed specific influences on each larval stage. Any increase in density was regulated by dissolved oxygen and electrical conductivity content at all larval stages. Furthermore, total phosphorus affected the density of F1 and F3 larvae. The interaction between reservoir area and precipitation, nitrate content, phosphate concentrations, and water temperature had the most influence on the density of F2 and F3 larval stages; the F1 stage was mainly affected by calcium concentrations. The isolated effect of precipitation also contributed to the density of F2 and F3 larvae. Our findings shed light on the interaction between different phases of golden mussel larvae and the main nutrients found in reservoirs, which may be a determining factor in the rise in density of the non-native species in these systems.
Assuntos
Monitoramento Ambiental , Larva , Rios , Animais , Larva/crescimento & desenvolvimento , Rios/química , Mytilidae/crescimento & desenvolvimento , Uruguai , Ecossistema , Análise Espaço-Temporal , Estações do Ano , Poluentes Químicos da Água/análise , Espécies IntroduzidasRESUMO
Hydrobiogeochemical processes governing water quantity and quality are highly variable in space and time. Focusing on thirty river locations in Québec, Canada, three water quality hotness indices were used to classify watersheds as contaminant transport hotspots. Concentration and load data for suspended solids (SS), total nitrogen (TN), and total phosphorous (TP) were used to identify transport hotspots, and results were compared across hotness indices with different data requirements. The role of hydroclimatic and physiographic characteristics on the occurrence and temporal persistence of transport hotspots was examined. Results show that the identification of transport hotspots was dependent on both the type of data and the hotness index used. Relationships between temporal and spatial predictors, however, were generally consistent. Annual transport hotspot occurrence was found to be related to temporal characteristics such as the number of dry days, potential evapotranspiration, and snow water equivalent, while hotspot temporal persistence was correlated to landcover characteristics. Stark differences in the identification of SS, TN, and TP transport hotspots were attributed to differences in mobilization processes and provided insights into dominant water and nutrient flowpaths in the studied watersheds. This study highlighted the importance of comparing contaminant dynamics across watersheds even when high-frequency water quality data or discharge data are not available. Characterizing hotspot occurrence and persistence, among hotness indices and water quality parameters, could be useful for watershed managers when identifying problematic watersheds, exploring legacy effects, and establishing a prioritization framework for areas that would benefit from enhanced routine monitoring or targeted mitigation strategies.
Assuntos
Monitoramento Ambiental , Nitrogênio , Fósforo , Rios , Poluentes Químicos da Água , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Fósforo/análise , Rios/química , Quebeque , Nitrogênio/análise , Qualidade da Água , Movimentos da Água , Poluição Química da Água/estatística & dados numéricosRESUMO
Monitoring wild fish health and exposure effects in impacted rivers and streams with differing land use has become a valuable research tool. Smallmouth bass (Micropterus dolomieu) are a sensitive, indicator species that exhibit signs of immunosuppression and endocrine disruption in response to water quality changes and contaminant exposure. To determine the impact of agriculture and development on smallmouth bass health, two sites (a developed/agriculture site and a forested site) in the Susquehanna River watershed, Pennsylvania were selected where bass and water chemistry were sampled from 2015 to 2019. Smallmouth bass were sampled for histopathology to assess parasite and macrophage aggregate density in the liver and spleen, condition factor (Ktl), hepatic gene transcript abundance, hepatosomatic index (HSI), and a health assessment index (HAI). Land use at the developed/agriculture site included greater pesticide application rates and phytoestrogen crop cover and more detections and higher concentrations of pesticides, wastewater-associated contaminants, hormones, phytoestrogens, and mycotoxins than at the forested site. Additionally, at the developed/agriculture site, indicators of molecular changes, including oxidative stress, immune/inflammation, and lipid metabolism-related hepatic gene transcripts, were associated with more contaminants and land use variables. At both sites, there were multiple associations of contaminants with liver and/or spleen macrophage aggregate density, indicating that changes at the molecular level seemed to be a better indicator of exposures unique to each site. The findings illustrate the importance of timing for land management practices, the complex mixtures aquatic animals are exposed to, and the temporal changes in contaminant concentration. Agricultural practices that affect hepatic gene transcripts associated with immune function and disease resistance were demonstrated which could negatively affect smallmouth bass populations.
Assuntos
Bass , Monitoramento Ambiental , Rios , Poluentes Químicos da Água , Animais , Pennsylvania , Monitoramento Ambiental/métodos , Rios/química , Poluentes Químicos da Água/análise , Agricultura , Fígado , PraguicidasRESUMO
Biofilms are considered a basal resource with high nutritional quality in stream food webs, as periphytic algae are abundant of polyunsaturated fatty acids (PUFAs). PUFAs are essential for growth and reproduction of consumers who cannot or have very limited capacity to biosynthesize. Yet, how the nutritional quality based on PUFA of basal food sources changes with light intensity remains unclear. We conducted a manipulative experiment in mesocosms to explore the response and mechanisms of nutritional quality to shading, simulating riparian restoration. We found a significant increase in PUFA% (including arachidonic acid, ARA) under shading conditions. The increased PUFA is caused by the algal community succession from Cyanobacteria and Chlorophyta to Bacillariophyta which is abundant of PUFA (especially eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA). On the other hand, shading increased PUFA via upregulating enzymes such as Δ12 desaturase (FAD2, EC:1.14.19.6) and 3-ketoacyl-CoA synthase (KCS, EC:2.3.1.199) in the biosynthesis of unsaturated fatty acid elongation pathways. Our findings imply that riparian reforestation by decreasing light intensity increases the nutritional quality of basal resources in streams, which may enhance transfer of good quality carbon to consumers in higher trophic levels through bottom-up effects.
Assuntos
Ácidos Graxos Insaturados , Cadeia Alimentar , Luz , Rios , Rios/microbiologia , Rios/química , Ácidos Graxos Insaturados/análise , Ácidos Graxos Insaturados/metabolismo , Cianobactérias/metabolismo , Cianobactérias/crescimento & desenvolvimento , Clorófitas/metabolismo , Clorófitas/crescimento & desenvolvimento , Diatomáceas/metabolismo , Diatomáceas/crescimento & desenvolvimento , Valor NutritivoRESUMO
Benthic macroinvertebrate abundance and taxa richness associated with environmental variables were monitored monthly from September 2015 to August 2016 in the Nyamuhinga River. The benthic macroinvertebrate samples were collected using a D-frame aquatic net employing the man-time method. Environmental variables including pH, temperature, conductivity, and total dissolved solids (TDS) were measured using a Combo HI 98129 and GREISIN-GER 020 multimeters, and water flow was assessed using the Float Method procedure. The Shannon-Wiener and equitability indices were then calculated to assess diversity and richness, facilitating the comparison of diversity within sites or stations. A total of 35,142 macroinvertebrate individuals were collected from the 12 sampling sites belonging to 29 genera, 27 families, and 9 orders. Diptera were the most abundant (71.83%) followed by Odonata (9.13%) and Ephemeroptera (7.11%). The findings showed that taxa richness decreased from upstream to downstream. At the same time, absolute abundance increased from downstream to upstream due to riparian vegetation, substrate type, plant debris, and organic matter which are habitats for benthic macroinvertebrates in the river. Environmental variables such as flow, pH, temperature, conductivity, and TDS varied between sites and stations because of habitat disturbances, contaminant discharges into the catchment, and inflow of tributary waters into the river. The canonical correspondence analysis (CCA) results displayed that Eristalis and Chironomus were strongly associated with the flow, conductivity, TDS, temperature, and pH at the downstream sites related to anthropogenic activities from the catchment. From our results, the Nyamuhinga River needs conservation master plan/guidelines and increased awareness to reduce environmental impacts in Bukavu River catchments in the Lake Kivu basin.