The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based t...The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.展开更多
The accelerated decline of Arctic sea ice since the 1980s has paradoxically amplified greenhouse gas(GHG)emissions through increased shipping activities in this ecologically vulnerable region.This study investigates h...The accelerated decline of Arctic sea ice since the 1980s has paradoxically amplified greenhouse gas(GHG)emissions through increased shipping activities in this ecologically vulnerable region.This study investigates how to reconcile the decarbonization of Arctic shipping with conflicting environmental,economic,and geopolitical interests.Through systematic literature review and interest-balancing analysis,our findings identify three systemic barriers:(1)inadequate adaptation of International Maritime Organization(IMO)regulations to Arctic-specific environmental risks,(2)fragmented enforcement mechanisms among Arctic and non-Arctic States,and(3)technological limitations in clean fuel adoption for ice-class vessels.To address these challenges,a tripartite governance framework is proposed.First,legally binding amendments to International Convention for the Prevention of Pollution from Ships(MARPOL)Annex VI introducing Arctic-specific Energy Efficiency eXisting ship Index(EEXI)standards and extending energy efficiency regulations to fishing vessels.Second,a phased fuel transition prioritizing liquefied natural gas(LNG)and methanol,followed by hydrogen-ammonia synthetics.Third,enhanced multilateral cooperation through an Arctic Climate Shipping Alliance to coordinate joint research and development in cold-adapted technologies and ice-route optimization.By integrating United Nations Convention on the Law of the Sea(UNCLOS)obligations with IMO Polar Code implementation,this study advances a dynamic interest-balancing framework for policymakers,offering actionable pathways to achieve Paris Agreement targets while safeguarding Arctic ecosystems.展开更多
Chlorophyll a(Chl a)is a key photosynthetic pigment and an essential indicator of phytoplankton biomass.Accurate Chl a measurements are crucial for understanding marine biogeochemical processes.China launched the Chin...Chlorophyll a(Chl a)is a key photosynthetic pigment and an essential indicator of phytoplankton biomass.Accurate Chl a measurements are crucial for understanding marine biogeochemical processes.China launched the Chinese Ocean Color and Temperature Scanner(COCTS)aboard the HY-1D satellite in 2020,yet its Chl a products require further validation in complex coastal waters.This study assesses HY-1D Chl a products in the Bohai and Yellow Seas,two optically complex coastal regions,using in situ data collected during multiple cruises.Additionally,we compare HY-1D Chl a products with those from the Moderate Resolution Imaging Spectroradiometer(MODIS)and the Visible Infrared Imaging Radiometer Suite(VIIRS).We observed that although Chl a products from HY-1D are generally consistent with those from the MODIS and VIIRS in spatial distribution,there are still significant errors when compared with in situ data.Therefore,we developed a new blended algorithm to improve the accuracy of HY-1D Chl a products.The algorithm distinguishes between turbid and relatively clean waters using a classification index based on the ratio of remote sensing reflectance(R_(rs)(λ)).After the initial classification,we developed targeted algorithms based on the optical properties of different water bodies.The new model shows a significant improvement,reducing the mean absolute percentage error(MAPE)from 43.1%to 24.3%.Additionally,merging Chl a data from HY-1D,MODIS,and VIIRS maintains good accuracy,with HY-1D Chl a products significantly enhancing data coverage and robustness.This research provides important support for producing high-quality HY-1D Chl a products for coastal waters.展开更多
This study provides an in-depth exploration of seaweed biodiversity in Nigeria’s coastal waters, a largely unexplored area for marine resources. There is a dearth of sufficient data on seaweed biodiversity in Nigeria...This study provides an in-depth exploration of seaweed biodiversity in Nigeria’s coastal waters, a largely unexplored area for marine resources. There is a dearth of sufficient data on seaweed biodiversity in Nigeria. The research aimed to assess the diversity and distribution of seaweeds in this region. Seaweed samples were collected by hand, using scrapers, at low tide from four stations identified by local fisherfolk and commercial divers. These samples were analyzed in the laboratory for species identification. A total of 39 seaweed taxa were identified, with Rhodophyta (red algae) being the most abundant (74%), followed by Chlorophyta (green algae) (21%) and Heterokontophyta (brown algae) (5%). The highest biomass species included Grateloupia sp., Chaetomorpha antennina, Gracilaria sp., Ceratodictyon variabile, Cladophora sp., Gelidium pusillum, Ulva sp., Blidingia minima, and Caloglossa leprieurii. Species abundance was highest on breakwater rocks and on the bodies of anchored or sunken vessels, while sandy beaches exhibited lower abundance. The findings reveal significant potential for Nigeria’s seaweed in aquaculture, climate change mitigation, and biotechnology. The study recommends further molecular research, expansion of sampling areas, and the development of sustainable seaweed cultivation practices to support Nigeria’s blue economy.展开更多
Motivated by the wide applications of empirical global ocean tide models in Earth science,particularly in shallow waters and coastal regions,we proposed an updated global ocean tide model representing all major diurna...Motivated by the wide applications of empirical global ocean tide models in Earth science,particularly in shallow waters and coastal regions,we proposed an updated global ocean tide model representing all major diurnal and semidiurnal tidal constituents.We integrated the development technique of the Technical University of Denmark(DTU10)model and calculated the residual tides using the intermediary FES2012 model.We utilized all available Topex/Poseidon,Jason-1,Ocean Surface Topography Mission(OSTM)/Jason-2 primary and tandem missions to develop the new model.To reduce the discrepancies between the model and in situ measurements estimated S2 tide constituent,the ERA-Interim model was selected for dry tropospheric correction of altimetry data.The newly developed model with an improved spatial resolution from 1/8°×1/8°to 1/16°×1/16°was assessed and compared against contemporary global ocean tide models using in situ measurements in coastal regions,continental shelf waters,marginal seas,and deep waters.The results demonstrate improvements in shallow waters and coastal regions,particularly in representative coastal re-gions such as the Northwest European Shelf and East Asian Marginal Seas.Moreover,the model performs well in simulating S_(2) and K_(2) tides with root mean square differences of 0.355 and 0.234 cm,respectively,against in situ measurements in deep waters world-wide.Compared with that of DTU10,the root sum square of the new model for the eight main tidal constituents decrease by 8.4%to 0.997 cm.展开更多
Water scarcity and environment deterioration have become main constraints to sustainable economic and social development.Scientifically assessing Water Resources Carrying Capacity(WRCC)is essential for the optimal all...Water scarcity and environment deterioration have become main constraints to sustainable economic and social development.Scientifically assessing Water Resources Carrying Capacity(WRCC)is essential for the optimal allocation of regional water resources.The hilly area at the northern foot of Yanshan Mountains is a key water conservation zone and an important water source for Beijing,Tianjin and Hebei.Grasping the current status and temporal trends of water quality and WRCC in representative small watersheds within this region is crucial for supporting rational water resources allocation and environment protection efforts.This study focuses on Pingquan City,a typical watershed in northern Hebei Province.Firstly,evaluation index systems for surface water quality,groundwater quality and WRCC were estab-lished based on the Pressure-State-Response(PSR)framework.Then,comprehensive evaluations of water quality and WRCC at the sub-watershed scale were conducted using the Varying Fuzzy Pattern Recogni-tion(VFPR)model.Finally,the rationality of the evaluation results was verified,and future scenarios were projected.Results showed that:(1)The average comprehensive evaluation scores for surface water and groundwater quality in the sub-watersheds were 1.44 and 1.46,respectively,indicating that both met the national Class II water quality standard and reflected a high-quality water environment.(2)From 2010 to 2020,the region's WRCC steadily improved,with scores rising from 2.99 to 2.83 and an average of 2.90,suggesting effective water resources management in Pingquan City.(3)According to scenario-based predic-tion,WRCC may slightly decline between 2025 and 2030,reaching 2.92 and 2.94,respectively,relative to 2020 levels.Therefore,future efforts should focus on strengthening scientific management and promoting the efficient use of water resources.Proactive measures are necessary to mitigate emerging contradiction and ensure the long-term stability and sustainability of the water resources system in the region.The evalua-tion system and spatiotemporal evolution patterns proposed in this study can provide a scientific basis for refined water resource management and ecological conservation in similar hilly areas.展开更多
Marine heatwaves(MHWs)have become increasingly frequent and persistent in the context of global warming and the related underlying mechanisms are strongly region-dependent.We employed the NOAA(National Oceanic and Atm...Marine heatwaves(MHWs)have become increasingly frequent and persistent in the context of global warming and the related underlying mechanisms are strongly region-dependent.We employed the NOAA(National Oceanic and Atmospheric Administration)CRW(Coral Reef Watch)daily mean sea surface temperature dataset spanning from 1985 to 2022 to comprehensively analyze the fundamental attributes and evolving patterns of marine heatwaves in the offshore waters of China.Eight pronounced marine heatwaves from frequently affected sensitive regions were investigated to explore their formation mechanisms.The relationship between the occurrences of marine heatwave and large-scale climate mode in the region was explored.Results show that the western Pacific subtropical high plays an essential role in triggering marine heatwaves in Chinese offshore waters,with an anomalous downward shortwave radiation flux acting to warm the sea surface,which is remotely associated to the large-scale sea surface temperature state.Distinct mechanisms for the MHWs were identified in the northern and southern offshore waters of China.MHWs in high latitudes(such as the Bohai Sea and the Yellow Sea)mainly occur during the negative phase of the Pacific Decadal Oscillation(PDO),while those in low latitudes(such as the South China Sea)are more common in about 5-month lags behind the El Niño,for which we purposed a mechanism to describe the main differences in the formation of MHWs in China and discussed the related implications.展开更多
Pingquan City,the origin of five rivers,serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas.In recent years,excessive ...Pingquan City,the origin of five rivers,serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas.In recent years,excessive mining and intensified human activities have severely disrupted the local ecosystem,creating an urgent need for ecological vulnerability assessment to enhance water conservation functions.This study employed the sensitivity-resilience-pressure model,integrating various data sources,including regional background,hydro-meteorological data,field investigations,remote sensing analysis,and socio-economic data.The weights of the model indices were determined using an entropy weighting model that combines principal component analysis and the analytic hierarchy process.Using the ArcGIS platform,the spatial distribution and driving forces of ecological vulnerability in 2020 were analyzed,providing valuable insights for regional ecological restoration.The results indicated that the overall Ecological Vulnerability Index(EVI)was 0.389,signifying moderate ecological vulnerability,with significant variation between watersheds.The Daling River Basin had a high EVI,with ecological vulnerability primarily in levels IV and V,indicating high ecological pressure,whereas the Laoniu River Basin had a low EVI,reflecting minimal ecological pressure.Soil type was identified as the primary driving factor,followed by elevation,temperature,and soil erosion as secondary factors.It is recommended to focus on key regions and critical factors while conducting comprehensive monitoring and assessment to ensure the long-term success of ecological management efforts.展开更多
Natural resource management is essential to sustain human well-being and the environment.Water and soil are two of the most important natural resources that require careful management.The western part of India faces m...Natural resource management is essential to sustain human well-being and the environment.Water and soil are two of the most important natural resources that require careful management.The western part of India faces multiple challenges,including climatic variability,soil degradation,water scarcity,deforestation,etc.The basin’s sub-watersheds are delineated and prioritised using the Soil and Water Assessment Tool(SWAT)and Sub Watershed Prioritization Tool(SWPT),respectively,using morphometric and topo-hydrological characteristics,and the sub-watersheds are further ranked using Weighted Sum Analysis(WSA).The findings indicate that SWS19,SWS18,SWS1,SWS17,SWS16,and SWS15,which are drained by the rivers Chambal,Kali Sindh,Mashi,Parbati,Parwan,and Beradi,are highly vulnerable sub-watersheds.By integrating remote sensing,GIS techniques,and quantitative morphometric analysis,parameters such as drainage density,stream frequency,bifurcation ratio,and slope gradient were evaluated.The analysis revealed critical sub-watersheds characterized by steep slopes,high drainage density,and poor vegetation cover,indicating their susceptibility to erosion and runoff.The findings underscore the necessity for targeted soil conservation measures,such as contour bunding,afforestation,and water retention structures.This study highlights the utility of geospatial tools for sustainable watershed management and provides a replicable framework for prioritizing sub-watersheds in similar regions.展开更多
Microplastic contamination is considered a major threat to the marine environment.Although microplastic pollution in the Pacific Ocean has been studied,its abundance,distribution,composition,and origin in the western ...Microplastic contamination is considered a major threat to the marine environment.Although microplastic pollution in the Pacific Ocean has been studied,its abundance,distribution,composition,and origin in the western Pacific Ocean remain unclear.Here,we investigated the abundance and distribution characteristics of microplastics in surface waters of the western Pacific Ocean and analyzed their potential sources.Results show that microplastics were widespread in the western Pacific Ocean,with abundance ranging from 0.03 to 2.36 particles/m^(3)(average 0.37±0.47 particles/m^(3)).Fibers/filaments and fragments were the main shapes of microplastics(71.6%)and the most abundant microplastic size class was<1.0 mm(42.4%).Significant differences in microplastic abundance were observed in different regions,with the lowest abundance in the South China Sea(0.03 particles/m^(3))and highest abundance in the seamount area in the western Pacific Ocean(0.58 particles/m^(3)).This study provides baseline data and insights into the fate and transportation of microplastics in the western Pacific region.展开更多
Microplastics(MPs)have been widely detected in marine environments,yet the pollution in terrestrial fresh waters in economically underdeveloped and remote areas is poorly understood.We investigated the abundance and d...Microplastics(MPs)have been widely detected in marine environments,yet the pollution in terrestrial fresh waters in economically underdeveloped and remote areas is poorly understood.We investigated the abundance and distribution of MPs in inland waters(including open waters in river,lake,reservoir,stream,and tap water and bottled water)in Guizhou,SW China,detected by Nile Red staining.Results show that MPs were detected in all samples,with the mean abundance of 3.5±1.9 items/mL in 34river water samples,3.9±1.9 items/mL in 14 lake and reservoir water samples,3.4±2.4 items/mL in 87 stream water samples,3.8±3.8 items/mL in 164 tap water samples,and 1.3±3.2 items/mL in 12 bottled water samples from 4 different brands.The MP abundance in open field waters(3.6±3.0 items/mL)was significantly higher than that in bottled water(1.3±3.2 items/mL)(P<0.05).The microplastics with particle sizes of 10-20μm accounted for more than 50%of all samples.The composition ratio of smalland medium-sized microplastics in open waters was higher than in tap and bottled water(P<0.05).The MPs abundance tended to increase with the decrease in particle size.Therefore,microplastic pollution varied in different degrees in open waters in economically underdeveloped and remote areas of the southwestern China,which is consistent with microplastic pollution in other similar water environments.This study provided a reference for understanding the microplastic content and pollution control in the inland waters in western and remote areas of China.展开更多
Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological component...Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological components of these watersheds has been altered by human activities,which directly impacts them through changes in land use.In Colombia,the lack of control over land-use in watersheds has affected the water regulation services of important tributaries,such as the Onzaga River,whose waters are mainly used for agricultural activities.For this reason,this study aims to evaluate how changes in land use in the basin affected the capacity of water regulation.For this,a statistical correlation analysis was conducted between the Water Regulation Index(WRI)and vegetation cover areas from 1985 to 2023.The study results indicate that the expansion of the anthropogenic vegetation covers,such as agriculture parches and grasslands,replacing different types of forests,and producing an adverse effect on the water regulation capacity for the basin.This demonstrated its decrease along with an increase in its variability,indicating that,in addition to its degradation,there is a greater irregularity in this ecosystem service.In conclusion,correlation analysis indicates that 93%of the change in water regulation regime is explained by the contraction of forest cover and the expansion of agricultural areas,degraded lands,and urban development.This study confirms the importance of preserving native vegetation cover in the watershed,especially in areas adjacent to watercourses with riparian forests.展开更多
Water quality is a critical global issue,especially in urban and semi-urban regions where natural and anthropogenic factors significantly influence surface water systems.This study evaluates the hydrochemical characte...Water quality is a critical global issue,especially in urban and semi-urban regions where natural and anthropogenic factors significantly influence surface water systems.This study evaluates the hydrochemical characteristics of surface water in the North of Tehran Rivers(NTRs),an essential water resource in a rapidly urbanizing region,using advanced clustering techniques,including Hierarchical Clustering Analysis(HCA),Fuzzy CMeans(FCM),Genetic Algorithm Fuzzy C-Means(GAFCM),and Self-Organizing Map(SOM).The research aims to address the scientific challenge of understanding spatial and temporal variability in water quality,focusing on physicochemical parameters,hydrochemical facies,and contamination sources.Water samples from six rivers collected over four seasons in 2020 were analyzed and classified into distinct clusters based on their chemical composition,revealing significant seasonal and spatial differences.Results showed that FCM and GAFCM consistently categorized the NTRs into two clusters during winter and spring and three in summer and autumn.These findings were supported by HCA and SOM,which identified clusters corresponding to specific river segments and contamination levels.The primary hydrochemical processes identified were mineral dissolution and weathering,with calcite,dolomite,and aragonite significantly influencing water chemistry.Additionally,human activities,such as wastewater discharge,were shown to contribute to elevated sulfate,nitrate,and phosphate concentrations,further corroborated by microbial analyses.By integrating HCA,FCM,and GAFCM with an artificial neural network(ANN)-based clustering method(SOM),this study provides a robust framework for evaluating surface water quality.The findings,supported by Gibbs diagrams,Hounslow ion ratio,and saturation indices,highlight the dominance of rock weathering and human impacts in shaping the hydrochemical dynamics of the NTRs.These insights contribute to the scientific understanding of water quality dynamics and offer practical guidance for sustainable water resource management and environmental protection in developing urban areas.展开更多
Antibiotics,as emerging pollutants,pose significant risks to aquatic ecosystems and human health by disrupting the endocrine systems of aquatic organisms and affecting ecosystem stability through food chain enrichment...Antibiotics,as emerging pollutants,pose significant risks to aquatic ecosystems and human health by disrupting the endocrine systems of aquatic organisms and affecting ecosystem stability through food chain enrichment.In a study conducted in Hebei Province,China,liquid chromatography-triple quadrupole-linear ion trap mass spectrometry(LC-TQ-LIT-MS)was used to analyze 90 different antibiotics in 31 water samples,including surface water,groundwater,and waste leachate from three urban landfills.This analysis included hormones,broad-spectrum antimicrobials,macrolides,tetracyclines,β-lactams,sulfonamides,and quinolones.The study’s results indicated that quinolones,β-lactams,and macrolides were the most frequently detected substances in the landfills.It is noteworthy that the concentrations of these antibiotics varied significantly among different cities,reflecting local production and living characteristics.The results of the tests showed that the concentration of amoxicillin was 1171 ng/L in surface water,811 ng/L in groundwater,and 1926 ng/L of ciprofloxacin in waste leachate.Furthermore,a consistent pattern was observed between the compounds present in the leachate,groundwater,and surface water at the three sites.Risk assessments revealed that the ecological risk was higher for surface water and lower for groundwater.This study is the first to systematically analyze the pollution status of antibiotics and hormones in the water around the landfill in Hebei Province,which not only fills the blank of groundwater-related research in Hebei Province but also provides key data support and theoretical basis for local groundwater hydrological and environmental detection and pollution prevention.展开更多
Global forest cover is undergoing significant transformations due to anthropogenic activities and natural disturbances,profoundly impacting hydrological processes.However,the inherent spatial heterogeneity within wate...Global forest cover is undergoing significant transformations due to anthropogenic activities and natural disturbances,profoundly impacting hydrological processes.However,the inherent spatial heterogeneity within watersheds leads to varied hydrological responses across spatiotemporal scales,challenging comprehensive assessment of logging impacts at the watershed scale.Here,we developed multiple forest logging scenarios using the soil and water assessment tool(SWAT)model for the Le'an River watershed,a 5,837 km2 subtropical watershed in China,to quantify the hydrological effects of forest logging across different spatiotemporal scales.Our results demonstrate that increasing forest logging ratios from 1.54% to 9.25% consistently enhanced ecohydrological sensitivity.However,sensitivity varied across spatiotemporal scales,with the rainy season(15.30%-15.81%)showing higher sensitivity than annual(11.56%-12.07%)and dry season(3.38%-5.57%)periods.Additionally,the ecohydrological sensitivity of logging varied significantly across the watershed,with midstream areas exhibiting the highest sensitivity(13.13%-13.25%),followed by downstream(11.87%-11.98%)and upstream regions(9.96%-10.05%).Furthermore,the whole watershed exhibited greater hydrological resilience to logging compared to upstream areas,with attenuated runoff changes due to scale effects.Scale effects were more pronounced during dry seasons((-8.13 to -42.13)×10^(4) m^(3)·month^(-1))than in the rainy season((-11.11 to -26.65)×10^(4) m^(3)·month^(-1)).These findings advance understanding of logging impacts on hydrology across different spatiotemporal scales in subtropical regions,providing valuable insights for forest management under increasing anthropogenic activities and climate change.展开更多
The continuous and rapid increase of chemical pollution in surface waters has become a pressing and widely recognized global concern.As emerging contaminants(ECs)in surface waters,pharmaceutical and personal care prod...The continuous and rapid increase of chemical pollution in surface waters has become a pressing and widely recognized global concern.As emerging contaminants(ECs)in surface waters,pharmaceutical and personal care products(PPCPs),and endocrine-disrupting compounds(EDCs)have attracted considerable attention due to their wide occurrence and potential threat to human health.Therefore,a comprehensive understanding of the occurrence and risks of ECs in Chinese surface waters is urgently required.This study summarizes and assesses the environmental occurrence concentrations and ecological risks of 42 pharmaceuticals,15 personal care products(PCPs),and 20 EDCs frequently detected in Chinese surface waters.The ECs were primarily detected in China’s densely populated and highly industrialized regions.Most detected PPCPs and EDCs had concentrations between ng/L toμg/L,whereas norfloxacin,caffeine,and erythromycin had relatively high contamination levels,even exceeding 2000 ng/L.Risk evaluation based on the risk quotient method revealed that 34 PPCPs and EDCs in Chinese surface waters did not pose a significant risk,whereas 4-nonylphenol,4-tert-octylphenol,17α-ethinyl estradiol,17β-estradiol,and triclocarban did.This review provides a comprehensive summary of the occurrence and associated hazards of typical PPCPs and EDCs in Chinese surface waters over the past decade,and will aid in the regulation and control of these ECs in Chinese surface waters。展开更多
The reliable application of field deployable fluorescent dissolved organic matter(fDOM)probes is hindered by several influencing factors which need to be compensated.This manuscript describes the corrections of temper...The reliable application of field deployable fluorescent dissolved organic matter(fDOM)probes is hindered by several influencing factors which need to be compensated.This manuscript describes the corrections of temperature,pH,turbidity and inner filter effect on fluorescence signal of a commercial fDOM probe(fDOMs).For this,Australian waters with wide ranging qualities were selected,e.g.dissolved organic carbon(DOC)ranging from∼1 to∼30 mg/L,specific UV absorbance at 254 nm from∼1 to∼6 L/m/mg and turbidity from∼1 to∼350 FNU.Laboratory-based model calibration experiments(MCEs)were performed.A model template was developed and used for the development of the correction models.For each factor,data generated through MCEs were used to determine model coefficient(α)values by fitting the generated model to the experimental data.Four discrete factor models were generated by determination of a factor-specificαvalue.Theαvalues derived for each water of the MCEs subset were consistent for each factor model.This indicated generic nature of the fourαvalues across wide-ranging water qualities.High correlation between fDOMs and DOC were achieved after applying the four-factor compensation models to new data(r,0.96,p<0.05).Also,average biases(and%)between DOC predicted through fDOMs and actual DOC were decreased by applying the four-factor compensationmodel(from3.54(60.9%)to 1.28(16.7%)mg/L DOC).These correction models were incorporated into a Mi-crosoft EXCEL-based software termed EXOf-Correct for ready-to-use applications.展开更多
Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.I...Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.It is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located nearby.This study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water surface.The results show that the spill overall profile is articulated in three major flow areas.The first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill site.The behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the model.The Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot.展开更多
Water erosion is a serious problem that leads to soil degradation,loss,and the destruction of structures.Assessing the risk of erosion and determining the affected areas has become crucial in order to understand the m...Water erosion is a serious problem that leads to soil degradation,loss,and the destruction of structures.Assessing the risk of erosion and determining the affected areas has become crucial in order to understand the main factors influencing its evolution and to minimize its impacts.This study focuses on evaluating the risk of erosion in the Assif el mal watershed,which is located in the High Atlas Mountains.The Erosion Potential Model(EPM)is used to estimate soil losses depending on various parameters such as lithology,hydrology,topography,and morphometry.Geographic information systems and remote sensing techniques are employed to map areas with high erosive potential and their relationship with the distribution of factors involved.Different digital elevation models are also used in this study to highlight the impact of data quality on the accuracy of the results.The findings reveal that approximately 59%of the total area in the Assif el mal basin has low to very low potential for soil losses,while 22%is moderately affected and 19.9%is at high to very high risk.It is therefore crucial to implement soil conservation measures to mitigate and prevent erosion risks.展开更多
文摘The title of the online version of the original article was revised.The title of the original article has been revised to:Hydrochemical characterization of surface waters in Northern Tehran:Integrating cluster-based techniques with Self-Organizing Maps.
基金supported by the Major Research Projects of the National Social Science Fund of China(NSFC,Grant no.23VHQ015).
文摘The accelerated decline of Arctic sea ice since the 1980s has paradoxically amplified greenhouse gas(GHG)emissions through increased shipping activities in this ecologically vulnerable region.This study investigates how to reconcile the decarbonization of Arctic shipping with conflicting environmental,economic,and geopolitical interests.Through systematic literature review and interest-balancing analysis,our findings identify three systemic barriers:(1)inadequate adaptation of International Maritime Organization(IMO)regulations to Arctic-specific environmental risks,(2)fragmented enforcement mechanisms among Arctic and non-Arctic States,and(3)technological limitations in clean fuel adoption for ice-class vessels.To address these challenges,a tripartite governance framework is proposed.First,legally binding amendments to International Convention for the Prevention of Pollution from Ships(MARPOL)Annex VI introducing Arctic-specific Energy Efficiency eXisting ship Index(EEXI)standards and extending energy efficiency regulations to fishing vessels.Second,a phased fuel transition prioritizing liquefied natural gas(LNG)and methanol,followed by hydrogen-ammonia synthetics.Third,enhanced multilateral cooperation through an Arctic Climate Shipping Alliance to coordinate joint research and development in cold-adapted technologies and ice-route optimization.By integrating United Nations Convention on the Law of the Sea(UNCLOS)obligations with IMO Polar Code implementation,this study advances a dynamic interest-balancing framework for policymakers,offering actionable pathways to achieve Paris Agreement targets while safeguarding Arctic ecosystems.
基金The National Key Research and Development Program of China under contract No.2021YFB3901304the National Natural Science Foundation of China under contract No.42842176181,42476173,and 42176179the Natural Science Foundation of Jiangsu Province under contract No.BK20211289.
文摘Chlorophyll a(Chl a)is a key photosynthetic pigment and an essential indicator of phytoplankton biomass.Accurate Chl a measurements are crucial for understanding marine biogeochemical processes.China launched the Chinese Ocean Color and Temperature Scanner(COCTS)aboard the HY-1D satellite in 2020,yet its Chl a products require further validation in complex coastal waters.This study assesses HY-1D Chl a products in the Bohai and Yellow Seas,two optically complex coastal regions,using in situ data collected during multiple cruises.Additionally,we compare HY-1D Chl a products with those from the Moderate Resolution Imaging Spectroradiometer(MODIS)and the Visible Infrared Imaging Radiometer Suite(VIIRS).We observed that although Chl a products from HY-1D are generally consistent with those from the MODIS and VIIRS in spatial distribution,there are still significant errors when compared with in situ data.Therefore,we developed a new blended algorithm to improve the accuracy of HY-1D Chl a products.The algorithm distinguishes between turbid and relatively clean waters using a classification index based on the ratio of remote sensing reflectance(R_(rs)(λ)).After the initial classification,we developed targeted algorithms based on the optical properties of different water bodies.The new model shows a significant improvement,reducing the mean absolute percentage error(MAPE)from 43.1%to 24.3%.Additionally,merging Chl a data from HY-1D,MODIS,and VIIRS maintains good accuracy,with HY-1D Chl a products significantly enhancing data coverage and robustness.This research provides important support for producing high-quality HY-1D Chl a products for coastal waters.
文摘This study provides an in-depth exploration of seaweed biodiversity in Nigeria’s coastal waters, a largely unexplored area for marine resources. There is a dearth of sufficient data on seaweed biodiversity in Nigeria. The research aimed to assess the diversity and distribution of seaweeds in this region. Seaweed samples were collected by hand, using scrapers, at low tide from four stations identified by local fisherfolk and commercial divers. These samples were analyzed in the laboratory for species identification. A total of 39 seaweed taxa were identified, with Rhodophyta (red algae) being the most abundant (74%), followed by Chlorophyta (green algae) (21%) and Heterokontophyta (brown algae) (5%). The highest biomass species included Grateloupia sp., Chaetomorpha antennina, Gracilaria sp., Ceratodictyon variabile, Cladophora sp., Gelidium pusillum, Ulva sp., Blidingia minima, and Caloglossa leprieurii. Species abundance was highest on breakwater rocks and on the bodies of anchored or sunken vessels, while sandy beaches exhibited lower abundance. The findings reveal significant potential for Nigeria’s seaweed in aquaculture, climate change mitigation, and biotechnology. The study recommends further molecular research, expansion of sampling areas, and the development of sustainable seaweed cultivation practices to support Nigeria’s blue economy.
基金supported by the open funding of the Technology Innovation Center for South China Sea Re-mote Sensing,Surveying and Mapping Collaborative Ap-plication,Ministry of Natural Resources,P.R.China(No.RSSMCA-2024-B001)the National Natural Science Foundation of China(Nos.T2261149752 and 42476172).
文摘Motivated by the wide applications of empirical global ocean tide models in Earth science,particularly in shallow waters and coastal regions,we proposed an updated global ocean tide model representing all major diurnal and semidiurnal tidal constituents.We integrated the development technique of the Technical University of Denmark(DTU10)model and calculated the residual tides using the intermediary FES2012 model.We utilized all available Topex/Poseidon,Jason-1,Ocean Surface Topography Mission(OSTM)/Jason-2 primary and tandem missions to develop the new model.To reduce the discrepancies between the model and in situ measurements estimated S2 tide constituent,the ERA-Interim model was selected for dry tropospheric correction of altimetry data.The newly developed model with an improved spatial resolution from 1/8°×1/8°to 1/16°×1/16°was assessed and compared against contemporary global ocean tide models using in situ measurements in coastal regions,continental shelf waters,marginal seas,and deep waters.The results demonstrate improvements in shallow waters and coastal regions,particularly in representative coastal re-gions such as the Northwest European Shelf and East Asian Marginal Seas.Moreover,the model performs well in simulating S_(2) and K_(2) tides with root mean square differences of 0.355 and 0.234 cm,respectively,against in situ measurements in deep waters world-wide.Compared with that of DTU10,the root sum square of the new model for the eight main tidal constituents decrease by 8.4%to 0.997 cm.
基金financially supported by China Geological Survey Project(No.DD20220954)Open Funding Project of the Key Laboratory of Groundwater Sciences and Engineering,Ministry of Natural Resources(No.SK202301-4)+2 种基金Science and Technology Innovation Foundation of Comprehensive Survey&Command Center for Natural Resources(No.KC20240003)Yanzhao Shanshui Science and Innovation Fund of Langfang Integrated Natural Resources Survey Center,China Geological Survey(No.YZSSJJ202401-001)Open Foundation of the Key Laboratory of Coupling Process and Effect of Natural Resources Elements(No.2022KFKTC009).
文摘Water scarcity and environment deterioration have become main constraints to sustainable economic and social development.Scientifically assessing Water Resources Carrying Capacity(WRCC)is essential for the optimal allocation of regional water resources.The hilly area at the northern foot of Yanshan Mountains is a key water conservation zone and an important water source for Beijing,Tianjin and Hebei.Grasping the current status and temporal trends of water quality and WRCC in representative small watersheds within this region is crucial for supporting rational water resources allocation and environment protection efforts.This study focuses on Pingquan City,a typical watershed in northern Hebei Province.Firstly,evaluation index systems for surface water quality,groundwater quality and WRCC were estab-lished based on the Pressure-State-Response(PSR)framework.Then,comprehensive evaluations of water quality and WRCC at the sub-watershed scale were conducted using the Varying Fuzzy Pattern Recogni-tion(VFPR)model.Finally,the rationality of the evaluation results was verified,and future scenarios were projected.Results showed that:(1)The average comprehensive evaluation scores for surface water and groundwater quality in the sub-watersheds were 1.44 and 1.46,respectively,indicating that both met the national Class II water quality standard and reflected a high-quality water environment.(2)From 2010 to 2020,the region's WRCC steadily improved,with scores rising from 2.99 to 2.83 and an average of 2.90,suggesting effective water resources management in Pingquan City.(3)According to scenario-based predic-tion,WRCC may slightly decline between 2025 and 2030,reaching 2.92 and 2.94,respectively,relative to 2020 levels.Therefore,future efforts should focus on strengthening scientific management and promoting the efficient use of water resources.Proactive measures are necessary to mitigate emerging contradiction and ensure the long-term stability and sustainability of the water resources system in the region.The evalua-tion system and spatiotemporal evolution patterns proposed in this study can provide a scientific basis for refined water resource management and ecological conservation in similar hilly areas.
基金Supported by the National Natural Science Foundation of China(No.41905089)the Laoshan Laboratory(No.LSKJ202202404)+1 种基金the Startup Foundation for Introducing Talent of NUIST,Jiangsu Innovation Research Group(No.JSSCTD202346)the Undergraduates Innovation and Entrepreneurship Training Program of Jiangsu Province(No.202310300087Y)。
文摘Marine heatwaves(MHWs)have become increasingly frequent and persistent in the context of global warming and the related underlying mechanisms are strongly region-dependent.We employed the NOAA(National Oceanic and Atmospheric Administration)CRW(Coral Reef Watch)daily mean sea surface temperature dataset spanning from 1985 to 2022 to comprehensively analyze the fundamental attributes and evolving patterns of marine heatwaves in the offshore waters of China.Eight pronounced marine heatwaves from frequently affected sensitive regions were investigated to explore their formation mechanisms.The relationship between the occurrences of marine heatwave and large-scale climate mode in the region was explored.Results show that the western Pacific subtropical high plays an essential role in triggering marine heatwaves in Chinese offshore waters,with an anomalous downward shortwave radiation flux acting to warm the sea surface,which is remotely associated to the large-scale sea surface temperature state.Distinct mechanisms for the MHWs were identified in the northern and southern offshore waters of China.MHWs in high latitudes(such as the Bohai Sea and the Yellow Sea)mainly occur during the negative phase of the Pacific Decadal Oscillation(PDO),while those in low latitudes(such as the South China Sea)are more common in about 5-month lags behind the El Niño,for which we purposed a mechanism to describe the main differences in the formation of MHWs in China and discussed the related implications.
基金supported by the project of China Geological Survey(No.DD20220954)Open Funding Project of the Key Laboratory of Groundwater Sciences and Engineering,Ministry of Natural Resources(No.SK202301-4)+1 种基金Open Foundation of the Key Laboratory of Coupling Process and Effect of Natural Resources Elements(No.2022KFKTC009)Yanzhao Shanshui Science and Innovation Fund of Langfang Integrated Natural Resources Survey Center,China Geological Survey(No.YZSSJJ202401-001).
文摘Pingquan City,the origin of five rivers,serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas.In recent years,excessive mining and intensified human activities have severely disrupted the local ecosystem,creating an urgent need for ecological vulnerability assessment to enhance water conservation functions.This study employed the sensitivity-resilience-pressure model,integrating various data sources,including regional background,hydro-meteorological data,field investigations,remote sensing analysis,and socio-economic data.The weights of the model indices were determined using an entropy weighting model that combines principal component analysis and the analytic hierarchy process.Using the ArcGIS platform,the spatial distribution and driving forces of ecological vulnerability in 2020 were analyzed,providing valuable insights for regional ecological restoration.The results indicated that the overall Ecological Vulnerability Index(EVI)was 0.389,signifying moderate ecological vulnerability,with significant variation between watersheds.The Daling River Basin had a high EVI,with ecological vulnerability primarily in levels IV and V,indicating high ecological pressure,whereas the Laoniu River Basin had a low EVI,reflecting minimal ecological pressure.Soil type was identified as the primary driving factor,followed by elevation,temperature,and soil erosion as secondary factors.It is recommended to focus on key regions and critical factors while conducting comprehensive monitoring and assessment to ensure the long-term success of ecological management efforts.
文摘Natural resource management is essential to sustain human well-being and the environment.Water and soil are two of the most important natural resources that require careful management.The western part of India faces multiple challenges,including climatic variability,soil degradation,water scarcity,deforestation,etc.The basin’s sub-watersheds are delineated and prioritised using the Soil and Water Assessment Tool(SWAT)and Sub Watershed Prioritization Tool(SWPT),respectively,using morphometric and topo-hydrological characteristics,and the sub-watersheds are further ranked using Weighted Sum Analysis(WSA).The findings indicate that SWS19,SWS18,SWS1,SWS17,SWS16,and SWS15,which are drained by the rivers Chambal,Kali Sindh,Mashi,Parbati,Parwan,and Beradi,are highly vulnerable sub-watersheds.By integrating remote sensing,GIS techniques,and quantitative morphometric analysis,parameters such as drainage density,stream frequency,bifurcation ratio,and slope gradient were evaluated.The analysis revealed critical sub-watersheds characterized by steep slopes,high drainage density,and poor vegetation cover,indicating their susceptibility to erosion and runoff.The findings underscore the necessity for targeted soil conservation measures,such as contour bunding,afforestation,and water retention structures.This study highlights the utility of geospatial tools for sustainable watershed management and provides a replicable framework for prioritizing sub-watersheds in similar regions.
基金Supported by the National Key Research and Development Program(No.2016YFC1402201)the China Ocean Mineral Resources R&D Association Project(No.DY135-E2-2-04)。
文摘Microplastic contamination is considered a major threat to the marine environment.Although microplastic pollution in the Pacific Ocean has been studied,its abundance,distribution,composition,and origin in the western Pacific Ocean remain unclear.Here,we investigated the abundance and distribution characteristics of microplastics in surface waters of the western Pacific Ocean and analyzed their potential sources.Results show that microplastics were widespread in the western Pacific Ocean,with abundance ranging from 0.03 to 2.36 particles/m^(3)(average 0.37±0.47 particles/m^(3)).Fibers/filaments and fragments were the main shapes of microplastics(71.6%)and the most abundant microplastic size class was<1.0 mm(42.4%).Significant differences in microplastic abundance were observed in different regions,with the lowest abundance in the South China Sea(0.03 particles/m^(3))and highest abundance in the seamount area in the western Pacific Ocean(0.58 particles/m^(3)).This study provides baseline data and insights into the fate and transportation of microplastics in the western Pacific region.
基金Supported by the National Key Research and Development Program of China(Nos.2018YFC1004300,2018YFC1004302)the Science&Technology Program of Guizhou Province(Nos.QKHHBZ[2020]3002,QKHPTRC-GCC[2022]039-1,QKH-J[2022]YB614)+1 种基金the Science&Technology Program of Zunyi City(No.ZHZ[2021]294)the National Innovation Program for College Students in China(No.201910661012)。
文摘Microplastics(MPs)have been widely detected in marine environments,yet the pollution in terrestrial fresh waters in economically underdeveloped and remote areas is poorly understood.We investigated the abundance and distribution of MPs in inland waters(including open waters in river,lake,reservoir,stream,and tap water and bottled water)in Guizhou,SW China,detected by Nile Red staining.Results show that MPs were detected in all samples,with the mean abundance of 3.5±1.9 items/mL in 34river water samples,3.9±1.9 items/mL in 14 lake and reservoir water samples,3.4±2.4 items/mL in 87 stream water samples,3.8±3.8 items/mL in 164 tap water samples,and 1.3±3.2 items/mL in 12 bottled water samples from 4 different brands.The MP abundance in open field waters(3.6±3.0 items/mL)was significantly higher than that in bottled water(1.3±3.2 items/mL)(P<0.05).The microplastics with particle sizes of 10-20μm accounted for more than 50%of all samples.The composition ratio of smalland medium-sized microplastics in open waters was higher than in tap and bottled water(P<0.05).The MPs abundance tended to increase with the decrease in particle size.Therefore,microplastic pollution varied in different degrees in open waters in economically underdeveloped and remote areas of the southwestern China,which is consistent with microplastic pollution in other similar water environments.This study provided a reference for understanding the microplastic content and pollution control in the inland waters in western and remote areas of China.
基金The authors would like to thank the Vice-chancellor of Research at the Universidad Militar Nueva Granada for the opportunity to develop project INV-ING-3966.
文摘Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological components of these watersheds has been altered by human activities,which directly impacts them through changes in land use.In Colombia,the lack of control over land-use in watersheds has affected the water regulation services of important tributaries,such as the Onzaga River,whose waters are mainly used for agricultural activities.For this reason,this study aims to evaluate how changes in land use in the basin affected the capacity of water regulation.For this,a statistical correlation analysis was conducted between the Water Regulation Index(WRI)and vegetation cover areas from 1985 to 2023.The study results indicate that the expansion of the anthropogenic vegetation covers,such as agriculture parches and grasslands,replacing different types of forests,and producing an adverse effect on the water regulation capacity for the basin.This demonstrated its decrease along with an increase in its variability,indicating that,in addition to its degradation,there is a greater irregularity in this ecosystem service.In conclusion,correlation analysis indicates that 93%of the change in water regulation regime is explained by the contraction of forest cover and the expansion of agricultural areas,degraded lands,and urban development.This study confirms the importance of preserving native vegetation cover in the watershed,especially in areas adjacent to watercourses with riparian forests.
文摘Water quality is a critical global issue,especially in urban and semi-urban regions where natural and anthropogenic factors significantly influence surface water systems.This study evaluates the hydrochemical characteristics of surface water in the North of Tehran Rivers(NTRs),an essential water resource in a rapidly urbanizing region,using advanced clustering techniques,including Hierarchical Clustering Analysis(HCA),Fuzzy CMeans(FCM),Genetic Algorithm Fuzzy C-Means(GAFCM),and Self-Organizing Map(SOM).The research aims to address the scientific challenge of understanding spatial and temporal variability in water quality,focusing on physicochemical parameters,hydrochemical facies,and contamination sources.Water samples from six rivers collected over four seasons in 2020 were analyzed and classified into distinct clusters based on their chemical composition,revealing significant seasonal and spatial differences.Results showed that FCM and GAFCM consistently categorized the NTRs into two clusters during winter and spring and three in summer and autumn.These findings were supported by HCA and SOM,which identified clusters corresponding to specific river segments and contamination levels.The primary hydrochemical processes identified were mineral dissolution and weathering,with calcite,dolomite,and aragonite significantly influencing water chemistry.Additionally,human activities,such as wastewater discharge,were shown to contribute to elevated sulfate,nitrate,and phosphate concentrations,further corroborated by microbial analyses.By integrating HCA,FCM,and GAFCM with an artificial neural network(ANN)-based clustering method(SOM),this study provides a robust framework for evaluating surface water quality.The findings,supported by Gibbs diagrams,Hounslow ion ratio,and saturation indices,highlight the dominance of rock weathering and human impacts in shaping the hydrochemical dynamics of the NTRs.These insights contribute to the scientific understanding of water quality dynamics and offer practical guidance for sustainable water resource management and environmental protection in developing urban areas.
基金jointly supported by a project of the China Geological Survey(DD20243375)Hebei Key Laboratory of Mineral Resources and Ecological Environment Monitoring(No.HBMREEM202403).
文摘Antibiotics,as emerging pollutants,pose significant risks to aquatic ecosystems and human health by disrupting the endocrine systems of aquatic organisms and affecting ecosystem stability through food chain enrichment.In a study conducted in Hebei Province,China,liquid chromatography-triple quadrupole-linear ion trap mass spectrometry(LC-TQ-LIT-MS)was used to analyze 90 different antibiotics in 31 water samples,including surface water,groundwater,and waste leachate from three urban landfills.This analysis included hormones,broad-spectrum antimicrobials,macrolides,tetracyclines,β-lactams,sulfonamides,and quinolones.The study’s results indicated that quinolones,β-lactams,and macrolides were the most frequently detected substances in the landfills.It is noteworthy that the concentrations of these antibiotics varied significantly among different cities,reflecting local production and living characteristics.The results of the tests showed that the concentration of amoxicillin was 1171 ng/L in surface water,811 ng/L in groundwater,and 1926 ng/L of ciprofloxacin in waste leachate.Furthermore,a consistent pattern was observed between the compounds present in the leachate,groundwater,and surface water at the three sites.Risk assessments revealed that the ecological risk was higher for surface water and lower for groundwater.This study is the first to systematically analyze the pollution status of antibiotics and hormones in the water around the landfill in Hebei Province,which not only fills the blank of groundwater-related research in Hebei Province but also provides key data support and theoretical basis for local groundwater hydrological and environmental detection and pollution prevention.
基金supported by the National Natural Science Foundation of China(No.31660234).
文摘Global forest cover is undergoing significant transformations due to anthropogenic activities and natural disturbances,profoundly impacting hydrological processes.However,the inherent spatial heterogeneity within watersheds leads to varied hydrological responses across spatiotemporal scales,challenging comprehensive assessment of logging impacts at the watershed scale.Here,we developed multiple forest logging scenarios using the soil and water assessment tool(SWAT)model for the Le'an River watershed,a 5,837 km2 subtropical watershed in China,to quantify the hydrological effects of forest logging across different spatiotemporal scales.Our results demonstrate that increasing forest logging ratios from 1.54% to 9.25% consistently enhanced ecohydrological sensitivity.However,sensitivity varied across spatiotemporal scales,with the rainy season(15.30%-15.81%)showing higher sensitivity than annual(11.56%-12.07%)and dry season(3.38%-5.57%)periods.Additionally,the ecohydrological sensitivity of logging varied significantly across the watershed,with midstream areas exhibiting the highest sensitivity(13.13%-13.25%),followed by downstream(11.87%-11.98%)and upstream regions(9.96%-10.05%).Furthermore,the whole watershed exhibited greater hydrological resilience to logging compared to upstream areas,with attenuated runoff changes due to scale effects.Scale effects were more pronounced during dry seasons((-8.13 to -42.13)×10^(4) m^(3)·month^(-1))than in the rainy season((-11.11 to -26.65)×10^(4) m^(3)·month^(-1)).These findings advance understanding of logging impacts on hydrology across different spatiotemporal scales in subtropical regions,providing valuable insights for forest management under increasing anthropogenic activities and climate change.
基金supported by the National Natural Science Foundation of China(No.22176199)the Key R&D Program of Shandong Province(No.2020CXGC011202)+1 种基金the Jinan University and Institute Innovation Team Project(No.2021GXRC061)the Research Center for Eco-Environmental Science(No.RCEES-TDZ-2021-14).
文摘The continuous and rapid increase of chemical pollution in surface waters has become a pressing and widely recognized global concern.As emerging contaminants(ECs)in surface waters,pharmaceutical and personal care products(PPCPs),and endocrine-disrupting compounds(EDCs)have attracted considerable attention due to their wide occurrence and potential threat to human health.Therefore,a comprehensive understanding of the occurrence and risks of ECs in Chinese surface waters is urgently required.This study summarizes and assesses the environmental occurrence concentrations and ecological risks of 42 pharmaceuticals,15 personal care products(PCPs),and 20 EDCs frequently detected in Chinese surface waters.The ECs were primarily detected in China’s densely populated and highly industrialized regions.Most detected PPCPs and EDCs had concentrations between ng/L toμg/L,whereas norfloxacin,caffeine,and erythromycin had relatively high contamination levels,even exceeding 2000 ng/L.Risk evaluation based on the risk quotient method revealed that 34 PPCPs and EDCs in Chinese surface waters did not pose a significant risk,whereas 4-nonylphenol,4-tert-octylphenol,17α-ethinyl estradiol,17β-estradiol,and triclocarban did.This review provides a comprehensive summary of the occurrence and associated hazards of typical PPCPs and EDCs in Chinese surface waters over the past decade,and will aid in the regulation and control of these ECs in Chinese surface waters。
基金an Australian Research Council Linkage Project,grant number LP160100217.
文摘The reliable application of field deployable fluorescent dissolved organic matter(fDOM)probes is hindered by several influencing factors which need to be compensated.This manuscript describes the corrections of temperature,pH,turbidity and inner filter effect on fluorescence signal of a commercial fDOM probe(fDOMs).For this,Australian waters with wide ranging qualities were selected,e.g.dissolved organic carbon(DOC)ranging from∼1 to∼30 mg/L,specific UV absorbance at 254 nm from∼1 to∼6 L/m/mg and turbidity from∼1 to∼350 FNU.Laboratory-based model calibration experiments(MCEs)were performed.A model template was developed and used for the development of the correction models.For each factor,data generated through MCEs were used to determine model coefficient(α)values by fitting the generated model to the experimental data.Four discrete factor models were generated by determination of a factor-specificαvalue.Theαvalues derived for each water of the MCEs subset were consistent for each factor model.This indicated generic nature of the fourαvalues across wide-ranging water qualities.High correlation between fDOMs and DOC were achieved after applying the four-factor compensation models to new data(r,0.96,p<0.05).Also,average biases(and%)between DOC predicted through fDOMs and actual DOC were decreased by applying the four-factor compensationmodel(from3.54(60.9%)to 1.28(16.7%)mg/L DOC).These correction models were incorporated into a Mi-crosoft EXCEL-based software termed EXOf-Correct for ready-to-use applications.
文摘Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social implications.It is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located nearby.This study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water surface.The results show that the spill overall profile is articulated in three major flow areas.The first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill site.The behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the model.The Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot.
文摘Water erosion is a serious problem that leads to soil degradation,loss,and the destruction of structures.Assessing the risk of erosion and determining the affected areas has become crucial in order to understand the main factors influencing its evolution and to minimize its impacts.This study focuses on evaluating the risk of erosion in the Assif el mal watershed,which is located in the High Atlas Mountains.The Erosion Potential Model(EPM)is used to estimate soil losses depending on various parameters such as lithology,hydrology,topography,and morphometry.Geographic information systems and remote sensing techniques are employed to map areas with high erosive potential and their relationship with the distribution of factors involved.Different digital elevation models are also used in this study to highlight the impact of data quality on the accuracy of the results.The findings reveal that approximately 59%of the total area in the Assif el mal basin has low to very low potential for soil losses,while 22%is moderately affected and 19.9%is at high to very high risk.It is therefore crucial to implement soil conservation measures to mitigate and prevent erosion risks.
