Environmental problems from heavy metals(HMs)attract global attention.Accurately identifying sources and quantitatively evaluating ecological risks are keys for HMs pollution prevention.Dongting Lake in China was inve...Environmental problems from heavy metals(HMs)attract global attention.Accurately identifying sources and quantitatively evaluating ecological risks are keys for HMs pollution prevention.Dongting Lake in China was investigated through integrated methods like positive matrix factorization and Nemerow integrated risk index to examine spatial distribution,contamination characteristics,pollution sources,and the contribution of each source and pollutant to the ecological risk of 14 HMs in its surface sediments.Results showed that the mean concentrations of HMs were 0.82-9.44 times greater than the corresponding background values.The spatial distribution of HMs varied significantly,with high values of As,Cd,Mn,Pb,Sn,Tl and Zn concentrated in the sediments from Xiangjiang inlet and Yangtze outlet;Co,Cr,Cu,Ni and V in the Lishui sediments;Hg and Sb in the sediments from Yuanjiang and Zishui inlets,respectively.The accumulation of HMs was affected by five sources:mercury mining and atmospheric deposition(F1)(17.99%),urban domestic sewage and industrial sewage discharge(F2)(24.44%),antimony ore mining and smelting(F3)(6.50%),non-ferrous metal mining and extended processing industrial sources(F4)(15.72%),and mixed sources mainly from natural sources and agricultural sources(F5)(35.35%).F1 and F2 were identified as priority pollution sources;Cd,Hg,Tl,Sb and As,especially Cd and Hg,posed relatively high ecological risks and were prioritized HMs for control.展开更多
The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate ch...The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate change have always been the focus of scientists.To well understand the sedimentary environment of the sea area,we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements(RSEs)and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation.The ratios of Mo/U(average 2.22),(Cu+Mo)/Zn(average 1.51),and the results ofδCe<1 of the sediment samples,all indicate the reduction of the sedimentary environment.In addition,the ratio of pristane(Pr)to phytane(Ph),C30diahopane to C30 hopane,and diasterane to sterane were low in all samples,on average of 1.03,0.9,and 0.33,respectively.The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment.Through the analysis of sediment characteristics,material sources,and ocean currents,we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER.We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors,such as terrestrial input of materials,productivity at sea surface,and sediment particle size.展开更多
Under the steadily intensifying human activities in coastal areas,it is crucial to distinguish the sources of organic matter(OM)in sediments for better understanding of the environmental change.In this study,25 surfac...Under the steadily intensifying human activities in coastal areas,it is crucial to distinguish the sources of organic matter(OM)in sediments for better understanding of the environmental change.In this study,25 surface sediments collected along the harbor and creeks areas off Karachi coast were used for total organic carbon(TOC),total nitrogen(TN),stable carbon(δ^(13)C)and nitrogen(δ^(15)N)isotopic compositions,phytoplankton biomarkers(brassicasterol,dinosterol and cholesterol)and glycerol dialkyl glycerol tetraethers(GDGTs)analyses,to trace the distribution of OM and identify its sources.TOC,TN,δ^(13)C,and δ^(15)N are in the range of 0.04% to 5.28%,0.01% to 0.57%,-17.55‰ to -26.31‰,and 2.83‰ to 6.04‰,respectively.C/N values range from 4.24 to 21.04.The δ^(13)C,δ^(15)N,C/N,BIT(Branched Isoprenoid Tetraether)index together with phytoplankton biomarkers show both marine and terrestrial OM input to the creeks and Harbor stations.In contrast,the stations from Western Coast indicate a marine source predominance.A clearly impact of human activities is seen from sediments near river mouths.展开更多
This study aimed to determine variations in water quality index(WQI)and physicochemical properties of surface water and bottom sediments of selected coastal beaches of Niger Delta,Southern Nigeria.The water quality of...This study aimed to determine variations in water quality index(WQI)and physicochemical properties of surface water and bottom sediments of selected coastal beaches of Niger Delta,Southern Nigeria.The water quality of the river is categorized into five classes,which are classes I,II,III,IV and V based on the WQI(derived from the determination of DO,BOD,COD,TSS and ammonia and pH).Water and bottom sediment samples were analysed using standard procedures.During the wet season,physicochemical parameters such as potential hydrogen(pH),electrical conductivity(EC),dissolved oxygen(DO),total dissolved solids(TDS)and salinity showed significant difference(p<0.05)across all the locations.During the dry season,parameters like EC,EA,pH,sodium(Na),sulphate(SO4),chloride(Cl-),potassium(K),effective cation exchange capacity(ECEC)and calcium(Ca)showed significant difference(p<0.05)across all the six sampled beaches while phosphate(PO4)did not show any clear significant difference across all the sampled locations.The general trend in the levels of physicochemical parameters revealed that temperature and pH were within those recommended by World Health Organization(WHO)and United States Environmental Protection Agency(USEPA)for both wet and dry season but EC and TDS were above the WHO and USEPA limit.Twenty one(21)water quality parameters from six sampling locations were studied and by applying WQI,the state of the six beach water was very unsuitable for drinking,swimming and recreational activities as at the time of this study.The water is only suitable for irrigation purpose.展开更多
Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific...Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific evidence for paleoceanography explaination. This study showed that biogenic silica content in surface sediments and its water depth have evidently positive correlation, and the correlation coefficient was up to 0.782. Biogenic silica content was very low in continental shelf shallows and could not reflect the productivity of siliceous micropaleontology in surface waters, which may be affected by sedimentary types and terrigenous matter dilution. Distribution of biogenic silica content in surface sediments from deep water areas showed that it could not only reflect the paleoproductivity of siliceous micropaleontology in surface waters, but also indicate the strong or feeble upwelling. Thus, it was further confirmed that using biogenic silica content in sediments to trace upwelling and its change was effective and reliable. The analyzed result showed that radiolariia and poriferous specula have more contribution for biogenic opal, comparing with diatom in surface sediments from the northern studied area, probably owing to the diatom dissolved easily away and eaten by other organisms with little effort. In the upwelling areas, radiolarian, diatom and poriferous specula all approximately showed high abundance, which was consistent with high biogenic silica content.展开更多
Based on grain size analysis for the offshore surface sediments of the Dalian Bay, the assemblages and distribution characteristics of grain size were acquired, and their sources and sedimentary environments as well a...Based on grain size analysis for the offshore surface sediments of the Dalian Bay, the assemblages and distribution characteristics of grain size were acquired, and their sources and sedimentary environments as well as the dominant factors were also discussed preliminarily. The results indicate that the silt has the highest content of 52% in average, followed by sand of 34%. Clay is enriched in the central plateau subregion with the average content of 14%. They are distributed with the strap-shape from east to west, which is consistent with the distribution pattern of minerals there. The coastal shallow-water slope in the north of the study area is characterized by the enrichment of coarser deposition, indicating strong hydrodynamic conditions and nearby source. With water depth increasing southward, silt and clay fraction, mainly enriched on a subaquatic platform with better sorting, are considered to be transported far away. To the further south of the study area with the deepest water off another subaquatic slop, coarse fraction is the highest, implying strong hydrodynamic conditions induced by tide currents which pass in and out the Bohai Sea and Yellow Sea Warm Current that enters the Bohai Sea.展开更多
The concentrations, accumulation and sources of 15 polycyclic aromatic hydrocarbons （PAHs） had been studied or evaluated in the surface layer sediments of Taizhou Bay, China. It showed that the concentrations of PAH...The concentrations, accumulation and sources of 15 polycyclic aromatic hydrocarbons （PAHs） had been studied or evaluated in the surface layer sediments of Taizhou Bay, China. It showed that the concentrations of PAHs ranged from 85.4 to 167.6 ng/g （averaged 138.62 ng/g）, and the highest level was found in Jiao Jiang Dock. Percentages of 2-, 3-, 4-, 5- and 6-cyclic aromatic hydrocarbons were 7.8 %, 42.1%, 33.3 %, 9.6 % and 7.2 % respectively. The accumulation indices of PAHs ranged from 532.7 to 1068.9 （averaged 807.5）, and the index of Phenanthrene was the highest （122.7）, while that of Benzo （a） Pyrene was the lowest （2.7） among them. In Taizhou Bay, PAHs in surface layer sediments came mainly from coal burning, partly from direct pollution of petroleum hydrocarbons.展开更多
We measured the content of six heavy-metal elements(Co,Cu,Zn,As,Cd,Pb)in 72 lake surface-sediment samples from the Xizang Autonomous Region(referred to as Xizang)of China,and calculated four indices:enrichment factor(...We measured the content of six heavy-metal elements(Co,Cu,Zn,As,Cd,Pb)in 72 lake surface-sediment samples from the Xizang Autonomous Region(referred to as Xizang)of China,and calculated four indices:enrichment factor(EF),geo-accumulation index(Igeo),pollution load index(PLI),and a comprehensive potential ecological risk index(RI)to explore the differences in the accumulation and the major sources of heavy metals,and to reveal the role of human activities in the ecological environment of high-elevation cold regions.Results show that the heavy-metal contents in lake surface sediment samples in eastern Xizang are much higher than those in central and western areas,and are also higher than the background value of surface soils.Their distribution can be related to regional sources of heavy metals:natural parent material(western Xizang),agriculture(eastern Xizang),mining-related industrial sources(central Xizang),and degree of development of road network(all of Xizang).The majority of lakes in Xizang have a relatively low risk of ecological harm,but there are notable regional peculiarities in the element content and evaluation indices and the lakes in eastern Xizang are at higher risk than those in central and western parts.Lakes at higher ecological risk(such as Lake Butuo(Lake 71)and Samu Co(Lake 68)),remind us that the potential influence of heavy-metal enrichment on lake sediments and aquatic plants should not be overlooked.展开更多
Neonicotinoid insecticides(NEOs)have become an integral part of the global insecticide market due to their high efficiency and low toxicity.However,their environmental persistence has raised significant ecological con...Neonicotinoid insecticides(NEOs)have become an integral part of the global insecticide market due to their high efficiency and low toxicity.However,their environmental persistence has raised significant ecological concerns.Dongting Lake represents a vital freshwater lake in China,and its ecosystem health directly affects regional ecological balance and people’s livelihoods.This study systematically investigated the occurrence characteristics and ecological risks of NEOs in water bodies and sediments across the Dongting Lake basin.Based on surface water and sediment samples collected from 26 representative sampling sites,this study quantified nine NEOs using liquid chromatography triple quadrupole mass spectrometry.Furthermore,it assessed ecological risks posed by the NEOs using the risk quotient(RQ)method and fugacity modeling.The results revealed the presence of six NEOs in the water bodies:imidacloprid(IMI),acetamiprid(ACE),clothianidin(CLO),thiamethoxam(THIA),flonicamid(FLO),and dinotefuran(DIN).The total concentrations of these six NEOs averaged 275.11 ng/L.Five predominant NEOs(i.e.,IMI,THIA,ACE,CLO,and DIN)were identified in the sediments,with a mean concentration of 0.31 ng/g.The NEO concentrations in the water bodies across the Dongting Lake basin increased in the order of the Xiangjiang,Zishui,Yuanjiang,and Lishui rivers(collectively referred to as the Four Rivers),the mainstream of Dongting Lake,the Xinqiang River,the Miluo River,and the Hudu,Ouchi,and Songzi rivers(collectively referred to as the Three Outlets).Sediments from tributaries progressively accumulate in the lake.The ecological risk assessment identified IMI and DIN as the highest-risk compounds(RQ>1),with high-risk areas concentrated in the mainstream of Dongting Lake and the Ouchi,Miluo,and Hudu rivers.The fugacity model showed that IMI,ACE,and THIA are prone to diffuse from sediments to water bodies in most areas,with fugacity fractions(ff)values of greater than 0.5.In contrast,the mainstream of Dongting Lake acts as a sink of CLO and DIN(ff values:<0.5).Sediments at the lake’s outlet emerge as an important sink of NEOs.Based on the results of this study,it is advisable to strengthen the supervision of NEO applications in agricultural areas and to implement zonal control strategies.These measures will help reduce ecological risks and protect the safety of water ecosystems in the Dongting Lake region.展开更多
As the most important component of marine siliceous organisms,diatoms are vital primary producers of the ocean that are often used as indicators of paleoenvironmental change.To understand the response of sedimental di...As the most important component of marine siliceous organisms,diatoms are vital primary producers of the ocean that are often used as indicators of paleoenvironmental change.To understand the response of sedimental diatoms to regional environmental changes and the factors affecting the distribution of sedimental diatoms in the Taiwan Strait,this study quantified and classified the diatoms found in surface sediments collected during four surveys from 2019 to 2020.Overall,118 diatom taxa and 44 genera were identified with total diatom abundance of 8-27353 valves/g.Four diatom assemblages representing different environments were identified.Among them,assemblageⅠrepresented a coastal environment,assemblageⅡcomprised warm water species of a coastal environment,AssemblageⅢrepresented a coastal environment affected markedly by exorheism,AssemblageⅣrepresented a group with lowest diatom abundance.Seasonal variation in total diatom abundance was controlled by seven environmental factors:depth,sea surface salinity,mean grain size,silicate,nitrite,nitrate,and phosphate.Spatiotemporal variation in each of the diatom assemblages was substantial and strongly affected by various currents,upwelling,and low-salinity water.Specifically,it was found that the succession of diatom assemblages reflects change in the range of influence of local warm currents.展开更多
Heavy metals, pharmaceuticals, and other wastes released into the environment can significantly influence environmental antibiotic resistance. We investigated the occurrence of 22 antimicrobial resistance genes(ARGs) ...Heavy metals, pharmaceuticals, and other wastes released into the environment can significantly influence environmental antibiotic resistance. We investigated the occurrence of 22 antimicrobial resistance genes(ARGs) and 10 heavy metal concentrations, and the relationship between ARGs and heavy metals in surface sediment from seven sites of Lake Taihu. The results showed significant correlations(p < 0.05) between sediment ARG levels,especially for tetracycline and sulfonamides(e.g., tet(A), tet(D), tet(E), tet(O), sul1, sul2 and int-1) and specific heavy metals(Fe, Mn, Cr, Cu, Zn, among others) in the Lake. In the surface sediments, heavy metals showed an interaction with resistance genes, but the strength of interaction was diminished with increasing depth. For most of the heavy metals, the concentration of elements in the top sediments was higher than that in other depths.Tetracycline resistance genes(tet(A), tet(B), tet(D), tet(E) and tet(O), β-lactam resistance genes(SHV, TEM, CTX, OXA and OXY) and sulfonamide resistance genes(sulA, sul1, sul2, sul3 and int-1) were detected. They showed a trend which inferred a statistically significant increase followed by decreases in the relative abundance of these ARGs(normalized to 16 S rRNA genes) with increasing depth. This study revealed that tet(A), tet(O), TEM, OXY, int-1, sul1 and sul3 were widespread in surface sediments with high abundance, indicating that these genes deserve more attention in future work.展开更多
Clay minerals of surface sediments in the South China Sea （SCS） are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis （GSTA） model. Results show that clay mineral ty...Clay minerals of surface sediments in the South China Sea （SCS） are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis （GSTA） model. Results show that clay mineral types in various sedimentary environments have different sediment sources and transport routes. Sediments in the northern SCS （north of 20°N） between the southwest of Taiwan Island and the outer mouth of the Pearl River have high contents of illite and chlorite, which are derived mainly from sediments on Taiwan Island and/or the Yangtze River. Sediments from the Pearl River are characterized by high kaolinite and low smectite content, and most are distributed in the area between the mouth of the Pearl River and northeast of Hainan Island and transported vertically from the continental shelf to the slope. Characterized by high illite content, sediments from Kalimantan Island are transported toward the Nansha Trough. Sediments from Luzon Island are related with volcanic materials, and are transported westwards according to smectite distribution. On the Sunda Shelf, sediments from the Mekong River are transported southeast in the north while sediments from the Indonesian islands are transported northward in the south. Ascertaining surface sediment sources and their transport routes will not only improve understanding of modem transportation and depositional processes, but also aid paleoenvironmental and paleoclimatic analysis of the SCS.展开更多
Natural surface coating samples （NSCSs） from the surface of shingles and surficial sediments （SSs） in the Songhua River, China were employed to investigate the relationship between NSCSs and SSs in fractions of he...Natural surface coating samples （NSCSs） from the surface of shingles and surficial sediments （SSs） in the Songhua River, China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals （Fe, Mn, Zn, Cu, Pb, and Cd） using the modified sequential extraction procedure （MSEP）. The results show that the differences between NSCSs and SSs in Fe fi＇actions were insignificant and Fe was dominantly present as residual phase （76.22% for NSCSs and 80.88% for SSs） and Fe-oxides phase （20.33% for NSCSs and 16.15% for SSs）. Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase （48.27%） and that in SSs present as residual phase （45.44%）. Zn, Cu, Pb and Cd were found dominantly in residual fractions （〉48%）, and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter （OM）, and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.展开更多
In this study, content and distribution of organic matters （OM） and lipid biomarkers in surface sediments from northern South China Sea （SCS） were identified to reveal the sources and transport of fine-grained sed...In this study, content and distribution of organic matters （OM） and lipid biomarkers in surface sediments from northern South China Sea （SCS） were identified to reveal the sources and transport of fine-grained sediments. Organic matters and lipid biomarkers exhibited distinct spatial variation in northern SCS. Terrestrial discharge from the Pearl River and some mountainous rivers in southwestern Taiwan may contribute to the relatively high organic matters in the corresponding sea areas. The detection of unsaturated fatty acid homologues suggested the algal and/or bacterial OM contribution to surface sediments. The composites and distribution of lipid biomarkers indicate their mixed sources from terrestrial plants, marine algae and bacterial. Together with the proof of clay min- eral composites in the sediments, the results suggested that the currents, including the Guangdong Coastal Current and Kuroshio Current, control the transport and distribution of terrestrial sediment and the sedimentary environment in the northern SCS.展开更多
Surface coatings and surficial sediments were obtained in four natural waters in Xianghai Wetland in China to study the role of surface coatings and surficial sediments in controlling the transporting and cycling of h...Surface coatings and surficial sediments were obtained in four natural waters in Xianghai Wetland in China to study the role of surface coatings and surficial sediments in controlling the transporting and cycling of heavy metals in aquatic environments. Pb and Cd adsorption to the surface coatings and surficial sediments were measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0 05 mol/L, 25℃ and pH 6 0 for surface coatings; and 0 005 mol/L CaCl 2 solution, 25℃ and pH 6 0 for surficial sediments). The Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb and Cd adsorption to the surface coatings and surficial sediments, and the component analyses of surface coatings and surficial sediments were also carried out. Correlation analyses between the maximum adsorption of Pb and Cd(Г max ) and the components in the surface coatings and surficial sediments suggested that there was a statistically significant trend for Pb and Cd adsorption(Г max ) to the surface coatings to increase with increasing in contents of Fe and Mn oxides in the surface coatings and surficial sediments. And the metal adsorption abilities of surface coatings were much stronger than those of surficial sediments, highlighting that in the same water, i.e. at the same pH and initial metal concentrations, the metals(such as lead and cadmium) in supernatant were feasible to be adsorbed by surface coatings than surficial sediments. The more importance of surface coatings than surficial sediments for adsorbing and cycling of heavy metals in aquatic environments was evidenced.展开更多
The content of organic carbon （OC） normalized to the specific surface area （SSA） of sediment is widely used to trace variations in OC loading （OC/SSA）. This study presents observations of OC/SSA of surface sedim...The content of organic carbon （OC） normalized to the specific surface area （SSA） of sediment is widely used to trace variations in OC loading （OC/SSA）. This study presents observations of OC/SSA of surface sediments collected in the Chukchi Sea, a typical Arctic marginal sea. Shelf sediments exhibit much higher OC/SSA values than slope sediments in the study area. Compared with OC/SSA values reported from the East Siberian Shelf and Mackenzie River, the slope sediments possess lower OC loading. This abrupt decrease in OC/SSA is mostly related to the lower primary production on slope as well as possible oxidization processes. The results of linear regression analysis between OC and SSA indicate a sedimentary source rock for the OC in the Chukchi Sea sediments. Moreover, shelf sediments with low SSA possess a larger rock OC fraction than slope sediments do. The dataset of the present study enables a more thorough understanding of regional OC cycling in the Chukchi Sea.展开更多
The distributions of different forms of nitrogen in the surface sediments of the southern Huanghai Sea are different and affected by various factors. The contents of IEF-N, SOEF-N and TN gradually decrease eastward, a...The distributions of different forms of nitrogen in the surface sediments of the southern Huanghai Sea are different and affected by various factors. The contents of IEF-N, SOEF-N and TN gradually decrease eastward, and those of SAEF-N northward, while those of WAEF-N westward. Around the seaport of the old Huanghe (Yellow) River, the contents of both SOEF-N and TN are the highest. Among all the factors, the content of fine sediment is the predominant factor to affect the distributions of different forms of nitrogen. The contents of IEF-N, SOEF-N, and TN have visibly positive correlation with the content of fine sediments, and the correlative coefficient is 0.68, 0.58 and 0.71 respectively, showing that the contents of the three forms of nitrogen increase with those of fine sediments. The content of WAEF-N is related to that of fine sediments to a certain extent, with a correlative coefficient of 0.35; while the content of SAEF-N is not related to that of fine sediments, showing that the content of SAEF-N is not controlled by fine grain-size fractions of sediments. In addition, the distributions of different forms of nitrogen are also interacted one another, and the contents of IEF-N and SOEF-N are obviously affected by TN, while those of inorganic nitrogen (WAEF-N, SAEF-N and IEF-N) are not affected by SOEF-N and TN obviously, although they are interacted each other.展开更多
To reveal the relative contribution of the components, Fe, Mn oxides or organic materials（OMs） in the surficial sediments（SSs）, and the natural surface coating samples（NSCSs） to adsorbing atrazine（AT）, a selec...To reveal the relative contribution of the components, Fe, Mn oxides or organic materials（OMs） in the surficial sediments（SSs）, and the natural surface coating samples（NSCSs） to adsorbing atrazine（AT）, a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting（NLSF） to estimate the relative contribution of the components. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, before and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs（NSCSs） facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs（NSCSs） particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar basis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in controlling the environmental behavior of AT in an aquatic environment.展开更多
Nine elements （As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn） in sediment samples at 7 sites （Site 1-7） from Suzhou Creek in Shanghai were analyzed with the Community Bareau of Reference （BCR） （sequential extraction （SE...Nine elements （As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn） in sediment samples at 7 sites （Site 1-7） from Suzhou Creek in Shanghai were analyzed with the Community Bareau of Reference （BCR） （sequential extraction （SE）） protocol and simultaneously extracted metals （SEM）/acid volatile sulfide （AVS） procedure to assess the metal bioavailability and toxicology in this area. The results showed that the BCR extraction can be utilized as an additional tool with the AVS method for assessing the potential bioavailability and toxicity of metals in sediments. Pollution from S5 （Site 5） was more severe than from other sites, especially Pb, Cu and Zn. Among all the sites, more than 80% of the total concentration of Fe existed in the residual fraction, As, Cr, Mn also dominated in the residual fraction （more than 50%）. While Cd, Ni and Zn （more than 35%） were mainly in the non-stable phase. Cu had a strong affinity with oxidizable phase and Pb varied from site to site. The SEM/AVS ratio was less than one in these sediments and results implied that the majority of Zn and Ni （〉 40%） were bound to AVS. In contrast, Pb, Cu and Cd were little bound to AVS due to their low ration of SEM-Pb, Cu, Cd to corresponding total concentration and relatively high Dorewater concentration.展开更多
The concentration of zinc, chromium, cadmium, nickel, lead and copper was measured on both surface sediments and core sediments in the Shenzhen Bay. The average contents of all metals have exceeded the background valu...The concentration of zinc, chromium, cadmium, nickel, lead and copper was measured on both surface sediments and core sediments in the Shenzhen Bay. The average contents of all metals have exceeded the background values in the coastal zone of Guangdong Province. Cadmium is a heavy pollution matter which indicates a strong pollution level according to the ecological risk coefficient method. The ecological risk index of the whole area is 299 which belongs to middle and strong level. The area with strong pollution level is the near shore area closing to the inside of Shenzhen Bay, Shakou area is in the middle level while the weak pollution level occurs in Shenzhenhe Estuary according to ecological risk index. The four sediment cores can be divided into two parts based on lead-210 dating, sediments size analysis and economic development period in surrounding areas since 1950 with strong human intervention. The sediment size, deposition rate and human activities have positive relationship with the contents of heavy metals which directly impact the pollution level of heavy metals in sediments in Shenzhen Bay.展开更多
基金financially supported by the Key Research and Development Program of Hunan Province,China(No.2023SK2006)the Natural Science Foundation of Hunan Province,China(No.2023JJ50057)+2 种基金the Science and Technology Plan Project of Geological Bureau of Hunan Province,China(No.HNGSTP202411)the Open Project of Key Laboratory of the Ministry of Natural Resources,China(No.BL202105)the Natural Science Foundation of Changsha City,China(No.kq2202090)。
文摘Environmental problems from heavy metals(HMs)attract global attention.Accurately identifying sources and quantitatively evaluating ecological risks are keys for HMs pollution prevention.Dongting Lake in China was investigated through integrated methods like positive matrix factorization and Nemerow integrated risk index to examine spatial distribution,contamination characteristics,pollution sources,and the contribution of each source and pollutant to the ecological risk of 14 HMs in its surface sediments.Results showed that the mean concentrations of HMs were 0.82-9.44 times greater than the corresponding background values.The spatial distribution of HMs varied significantly,with high values of As,Cd,Mn,Pb,Sn,Tl and Zn concentrated in the sediments from Xiangjiang inlet and Yangtze outlet;Co,Cr,Cu,Ni and V in the Lishui sediments;Hg and Sb in the sediments from Yuanjiang and Zishui inlets,respectively.The accumulation of HMs was affected by five sources:mercury mining and atmospheric deposition(F1)(17.99%),urban domestic sewage and industrial sewage discharge(F2)(24.44%),antimony ore mining and smelting(F3)(6.50%),non-ferrous metal mining and extended processing industrial sources(F4)(15.72%),and mixed sources mainly from natural sources and agricultural sources(F5)(35.35%).F1 and F2 were identified as priority pollution sources;Cd,Hg,Tl,Sb and As,especially Cd and Hg,posed relatively high ecological risks and were prioritized HMs for control.
基金Supported by the Science and Technology Development Foundation of South China Sea Bureau,Ministry of Natural Resources,China(No.230204)the National Program on Global Change and Air-Sea Interaction(No.GASI-02-IND-CJ04)+1 种基金the Natural Science Foundation of Guangdong Province,China(No.2021A1515012589)the Key Technologies Research and Development Program of Guangzhou,Guangdong Province,China(No.2023B03J1379)。
文摘The Ninety-East Ridge(NER)is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean.The sedimentary environment,ocean currents,and scientific issues related to climate change have always been the focus of scientists.To well understand the sedimentary environment of the sea area,we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements(RSEs)and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation.The ratios of Mo/U(average 2.22),(Cu+Mo)/Zn(average 1.51),and the results ofδCe<1 of the sediment samples,all indicate the reduction of the sedimentary environment.In addition,the ratio of pristane(Pr)to phytane(Ph),C30diahopane to C30 hopane,and diasterane to sterane were low in all samples,on average of 1.03,0.9,and 0.33,respectively.The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment.Through the analysis of sediment characteristics,material sources,and ocean currents,we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER.We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors,such as terrestrial input of materials,productivity at sea surface,and sediment particle size.
基金funded in part by the Ocean Negative Carbon Emissions(ONCE)Program,the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.SL2023MS019)the Scientific Research Fund of the Second Institute of Oceanography(No.JB2404)+3 种基金the National Natural Science Foundation of China(Nos.U23A2034,42076242,41941013,42176039,41906045)the Global Change and Air-Sea Interaction II Program(Nos.GASI-04-HYST-06,GASI-04-HYST-01)the Zhejiang Provincial Natural Science Foundation of China(No.LDT23D06023D06)the China Government Marine Scholarship。
文摘Under the steadily intensifying human activities in coastal areas,it is crucial to distinguish the sources of organic matter(OM)in sediments for better understanding of the environmental change.In this study,25 surface sediments collected along the harbor and creeks areas off Karachi coast were used for total organic carbon(TOC),total nitrogen(TN),stable carbon(δ^(13)C)and nitrogen(δ^(15)N)isotopic compositions,phytoplankton biomarkers(brassicasterol,dinosterol and cholesterol)and glycerol dialkyl glycerol tetraethers(GDGTs)analyses,to trace the distribution of OM and identify its sources.TOC,TN,δ^(13)C,and δ^(15)N are in the range of 0.04% to 5.28%,0.01% to 0.57%,-17.55‰ to -26.31‰,and 2.83‰ to 6.04‰,respectively.C/N values range from 4.24 to 21.04.The δ^(13)C,δ^(15)N,C/N,BIT(Branched Isoprenoid Tetraether)index together with phytoplankton biomarkers show both marine and terrestrial OM input to the creeks and Harbor stations.In contrast,the stations from Western Coast indicate a marine source predominance.A clearly impact of human activities is seen from sediments near river mouths.
文摘This study aimed to determine variations in water quality index(WQI)and physicochemical properties of surface water and bottom sediments of selected coastal beaches of Niger Delta,Southern Nigeria.The water quality of the river is categorized into five classes,which are classes I,II,III,IV and V based on the WQI(derived from the determination of DO,BOD,COD,TSS and ammonia and pH).Water and bottom sediment samples were analysed using standard procedures.During the wet season,physicochemical parameters such as potential hydrogen(pH),electrical conductivity(EC),dissolved oxygen(DO),total dissolved solids(TDS)and salinity showed significant difference(p<0.05)across all the locations.During the dry season,parameters like EC,EA,pH,sodium(Na),sulphate(SO4),chloride(Cl-),potassium(K),effective cation exchange capacity(ECEC)and calcium(Ca)showed significant difference(p<0.05)across all the six sampled beaches while phosphate(PO4)did not show any clear significant difference across all the sampled locations.The general trend in the levels of physicochemical parameters revealed that temperature and pH were within those recommended by World Health Organization(WHO)and United States Environmental Protection Agency(USEPA)for both wet and dry season but EC and TDS were above the WHO and USEPA limit.Twenty one(21)water quality parameters from six sampling locations were studied and by applying WQI,the state of the six beach water was very unsuitable for drinking,swimming and recreational activities as at the time of this study.The water is only suitable for irrigation purpose.
基金National Natural Science Foundation of China (No. 40476024)National Key Technology R&D Program (No. 2006BAB19B03)+1 种基金supported by Key Laboratory of Marginal Sea Geology, Chinese Academy of Sciences (No. MSGL0613)the Knowledge Innovation Program of the Chinese Academy of Sciences (No. SQ200808)
文摘Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific evidence for paleoceanography explaination. This study showed that biogenic silica content in surface sediments and its water depth have evidently positive correlation, and the correlation coefficient was up to 0.782. Biogenic silica content was very low in continental shelf shallows and could not reflect the productivity of siliceous micropaleontology in surface waters, which may be affected by sedimentary types and terrigenous matter dilution. Distribution of biogenic silica content in surface sediments from deep water areas showed that it could not only reflect the paleoproductivity of siliceous micropaleontology in surface waters, but also indicate the strong or feeble upwelling. Thus, it was further confirmed that using biogenic silica content in sediments to trace upwelling and its change was effective and reliable. The analyzed result showed that radiolariia and poriferous specula have more contribution for biogenic opal, comparing with diatom in surface sediments from the northern studied area, probably owing to the diatom dissolved easily away and eaten by other organisms with little effort. In the upwelling areas, radiolarian, diatom and poriferous specula all approximately showed high abundance, which was consistent with high biogenic silica content.
文摘Based on grain size analysis for the offshore surface sediments of the Dalian Bay, the assemblages and distribution characteristics of grain size were acquired, and their sources and sedimentary environments as well as the dominant factors were also discussed preliminarily. The results indicate that the silt has the highest content of 52% in average, followed by sand of 34%. Clay is enriched in the central plateau subregion with the average content of 14%. They are distributed with the strap-shape from east to west, which is consistent with the distribution pattern of minerals there. The coastal shallow-water slope in the north of the study area is characterized by the enrichment of coarser deposition, indicating strong hydrodynamic conditions and nearby source. With water depth increasing southward, silt and clay fraction, mainly enriched on a subaquatic platform with better sorting, are considered to be transported far away. To the further south of the study area with the deepest water off another subaquatic slop, coarse fraction is the highest, implying strong hydrodynamic conditions induced by tide currents which pass in and out the Bohai Sea and Yellow Sea Warm Current that enters the Bohai Sea.
文摘The concentrations, accumulation and sources of 15 polycyclic aromatic hydrocarbons （PAHs） had been studied or evaluated in the surface layer sediments of Taizhou Bay, China. It showed that the concentrations of PAHs ranged from 85.4 to 167.6 ng/g （averaged 138.62 ng/g）, and the highest level was found in Jiao Jiang Dock. Percentages of 2-, 3-, 4-, 5- and 6-cyclic aromatic hydrocarbons were 7.8 %, 42.1%, 33.3 %, 9.6 % and 7.2 % respectively. The accumulation indices of PAHs ranged from 532.7 to 1068.9 （averaged 807.5）, and the index of Phenanthrene was the highest （122.7）, while that of Benzo （a） Pyrene was the lowest （2.7） among them. In Taizhou Bay, PAHs in surface layer sediments came mainly from coal burning, partly from direct pollution of petroleum hydrocarbons.
基金Under the auspices of National Natural Science Foundation of China(No.42471179,42071107)。
文摘We measured the content of six heavy-metal elements(Co,Cu,Zn,As,Cd,Pb)in 72 lake surface-sediment samples from the Xizang Autonomous Region(referred to as Xizang)of China,and calculated four indices:enrichment factor(EF),geo-accumulation index(Igeo),pollution load index(PLI),and a comprehensive potential ecological risk index(RI)to explore the differences in the accumulation and the major sources of heavy metals,and to reveal the role of human activities in the ecological environment of high-elevation cold regions.Results show that the heavy-metal contents in lake surface sediment samples in eastern Xizang are much higher than those in central and western areas,and are also higher than the background value of surface soils.Their distribution can be related to regional sources of heavy metals:natural parent material(western Xizang),agriculture(eastern Xizang),mining-related industrial sources(central Xizang),and degree of development of road network(all of Xizang).The majority of lakes in Xizang have a relatively low risk of ecological harm,but there are notable regional peculiarities in the element content and evaluation indices and the lakes in eastern Xizang are at higher risk than those in central and western parts.Lakes at higher ecological risk(such as Lake Butuo(Lake 71)and Samu Co(Lake 68)),remind us that the potential influence of heavy-metal enrichment on lake sediments and aquatic plants should not be overlooked.
基金jointly supported by project of the China Geological Survey(DD20243375,DD20230478)the Key Research and Development Program of Hunan Province(2023SK2066)the Natural Science Foundation of Hunan Province(2024JJ7620).
文摘Neonicotinoid insecticides(NEOs)have become an integral part of the global insecticide market due to their high efficiency and low toxicity.However,their environmental persistence has raised significant ecological concerns.Dongting Lake represents a vital freshwater lake in China,and its ecosystem health directly affects regional ecological balance and people’s livelihoods.This study systematically investigated the occurrence characteristics and ecological risks of NEOs in water bodies and sediments across the Dongting Lake basin.Based on surface water and sediment samples collected from 26 representative sampling sites,this study quantified nine NEOs using liquid chromatography triple quadrupole mass spectrometry.Furthermore,it assessed ecological risks posed by the NEOs using the risk quotient(RQ)method and fugacity modeling.The results revealed the presence of six NEOs in the water bodies:imidacloprid(IMI),acetamiprid(ACE),clothianidin(CLO),thiamethoxam(THIA),flonicamid(FLO),and dinotefuran(DIN).The total concentrations of these six NEOs averaged 275.11 ng/L.Five predominant NEOs(i.e.,IMI,THIA,ACE,CLO,and DIN)were identified in the sediments,with a mean concentration of 0.31 ng/g.The NEO concentrations in the water bodies across the Dongting Lake basin increased in the order of the Xiangjiang,Zishui,Yuanjiang,and Lishui rivers(collectively referred to as the Four Rivers),the mainstream of Dongting Lake,the Xinqiang River,the Miluo River,and the Hudu,Ouchi,and Songzi rivers(collectively referred to as the Three Outlets).Sediments from tributaries progressively accumulate in the lake.The ecological risk assessment identified IMI and DIN as the highest-risk compounds(RQ>1),with high-risk areas concentrated in the mainstream of Dongting Lake and the Ouchi,Miluo,and Hudu rivers.The fugacity model showed that IMI,ACE,and THIA are prone to diffuse from sediments to water bodies in most areas,with fugacity fractions(ff)values of greater than 0.5.In contrast,the mainstream of Dongting Lake acts as a sink of CLO and DIN(ff values:<0.5).Sediments at the lake’s outlet emerge as an important sink of NEOs.Based on the results of this study,it is advisable to strengthen the supervision of NEO applications in agricultural areas and to implement zonal control strategies.These measures will help reduce ecological risks and protect the safety of water ecosystems in the Dongting Lake region.
基金The Natural Science Foundation of Fujian Province of China under contract No.2023J011378the National Key Research and Development Program of China under contract No.2019YFE0124700the Special Fund for Basic Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources,China under contract Nos 2019018 and 2020017.
文摘As the most important component of marine siliceous organisms,diatoms are vital primary producers of the ocean that are often used as indicators of paleoenvironmental change.To understand the response of sedimental diatoms to regional environmental changes and the factors affecting the distribution of sedimental diatoms in the Taiwan Strait,this study quantified and classified the diatoms found in surface sediments collected during four surveys from 2019 to 2020.Overall,118 diatom taxa and 44 genera were identified with total diatom abundance of 8-27353 valves/g.Four diatom assemblages representing different environments were identified.Among them,assemblageⅠrepresented a coastal environment,assemblageⅡcomprised warm water species of a coastal environment,AssemblageⅢrepresented a coastal environment affected markedly by exorheism,AssemblageⅣrepresented a group with lowest diatom abundance.Seasonal variation in total diatom abundance was controlled by seven environmental factors:depth,sea surface salinity,mean grain size,silicate,nitrite,nitrate,and phosphate.Spatiotemporal variation in each of the diatom assemblages was substantial and strongly affected by various currents,upwelling,and low-salinity water.Specifically,it was found that the succession of diatom assemblages reflects change in the range of influence of local warm currents.
基金supported by the National Natural Science Foundation of China(Nos.E51579075 and E51879084)the Jiangsu Natural Science Foundation for Excellent Youth(NoBK20160087)+2 种基金the Fundamental Research Funds for the Central Universities(No.2016B06714)the National Water Pollution Control and Treatment Science and Technology Major Project(No.2018ZX07208-4)a project funded through the Priority Academic Program Development of the Jiangsu Higher Education Institution
文摘Heavy metals, pharmaceuticals, and other wastes released into the environment can significantly influence environmental antibiotic resistance. We investigated the occurrence of 22 antimicrobial resistance genes(ARGs) and 10 heavy metal concentrations, and the relationship between ARGs and heavy metals in surface sediment from seven sites of Lake Taihu. The results showed significant correlations(p < 0.05) between sediment ARG levels,especially for tetracycline and sulfonamides(e.g., tet(A), tet(D), tet(E), tet(O), sul1, sul2 and int-1) and specific heavy metals(Fe, Mn, Cr, Cu, Zn, among others) in the Lake. In the surface sediments, heavy metals showed an interaction with resistance genes, but the strength of interaction was diminished with increasing depth. For most of the heavy metals, the concentration of elements in the top sediments was higher than that in other depths.Tetracycline resistance genes(tet(A), tet(B), tet(D), tet(E) and tet(O), β-lactam resistance genes(SHV, TEM, CTX, OXA and OXY) and sulfonamide resistance genes(sulA, sul1, sul2, sul3 and int-1) were detected. They showed a trend which inferred a statistically significant increase followed by decreases in the relative abundance of these ARGs(normalized to 16 S rRNA genes) with increasing depth. This study revealed that tet(A), tet(O), TEM, OXY, int-1, sul1 and sul3 were widespread in surface sediments with high abundance, indicating that these genes deserve more attention in future work.
基金Supported by the National Natural Science Foundation of China (No. 40631007)the National Basic Research Program of China (973 Program, Nos. 2007CB819505, 2009CB219502)+3 种基金the Ministry of Science and Technology of China (2006BAB19B03)the Knowledge Innovation Program of Chinese Academy of Sciences (Nos. SQ200713 and LYQY200704)the Open Fund of the Key Laboratory of Marginal Sea Geology, Chinese Academy of Sciences (No. MSGL08-16)the Open Fund of the Key Laboratory of Marine Geology and Environment, Chinese Academy of Sciences (No. MGE2008KG08)
文摘Clay minerals of surface sediments in the South China Sea （SCS） are analyzed with X-ray diffraction, and their transport is explored with a grain size trend analysis （GSTA） model. Results show that clay mineral types in various sedimentary environments have different sediment sources and transport routes. Sediments in the northern SCS （north of 20°N） between the southwest of Taiwan Island and the outer mouth of the Pearl River have high contents of illite and chlorite, which are derived mainly from sediments on Taiwan Island and/or the Yangtze River. Sediments from the Pearl River are characterized by high kaolinite and low smectite content, and most are distributed in the area between the mouth of the Pearl River and northeast of Hainan Island and transported vertically from the continental shelf to the slope. Characterized by high illite content, sediments from Kalimantan Island are transported toward the Nansha Trough. Sediments from Luzon Island are related with volcanic materials, and are transported westwards according to smectite distribution. On the Sunda Shelf, sediments from the Mekong River are transported southeast in the north while sediments from the Indonesian islands are transported northward in the south. Ascertaining surface sediment sources and their transport routes will not only improve understanding of modem transportation and depositional processes, but also aid paleoenvironmental and paleoclimatic analysis of the SCS.
基金The National Basic Research Program (973) of China (No. 2004CB3418500)
文摘Natural surface coating samples （NSCSs） from the surface of shingles and surficial sediments （SSs） in the Songhua River, China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals （Fe, Mn, Zn, Cu, Pb, and Cd） using the modified sequential extraction procedure （MSEP）. The results show that the differences between NSCSs and SSs in Fe fi＇actions were insignificant and Fe was dominantly present as residual phase （76.22% for NSCSs and 80.88% for SSs） and Fe-oxides phase （20.33% for NSCSs and 16.15% for SSs）. Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase （48.27%） and that in SSs present as residual phase （45.44%）. Zn, Cu, Pb and Cd were found dominantly in residual fractions （〉48%）, and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter （OM）, and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.
基金supported by the In-novative Program of CAS(No.KZCX2-YW-GJ03)973 Pro-ject(No.2009CB219502-04)+1 种基金Tfounded by the Natural Science Foundation of Guangdong Province(No.S2013010013744)Scientific Frontier Program for Young Talents of the South China Sea Institute of Oceanology,CAS(No.SQ200909)
文摘In this study, content and distribution of organic matters （OM） and lipid biomarkers in surface sediments from northern South China Sea （SCS） were identified to reveal the sources and transport of fine-grained sediments. Organic matters and lipid biomarkers exhibited distinct spatial variation in northern SCS. Terrestrial discharge from the Pearl River and some mountainous rivers in southwestern Taiwan may contribute to the relatively high organic matters in the corresponding sea areas. The detection of unsaturated fatty acid homologues suggested the algal and/or bacterial OM contribution to surface sediments. The composites and distribution of lipid biomarkers indicate their mixed sources from terrestrial plants, marine algae and bacterial. Together with the proof of clay min- eral composites in the sediments, the results suggested that the currents, including the Guangdong Coastal Current and Kuroshio Current, control the transport and distribution of terrestrial sediment and the sedimentary environment in the northern SCS.
文摘Surface coatings and surficial sediments were obtained in four natural waters in Xianghai Wetland in China to study the role of surface coatings and surficial sediments in controlling the transporting and cycling of heavy metals in aquatic environments. Pb and Cd adsorption to the surface coatings and surficial sediments were measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0 05 mol/L, 25℃ and pH 6 0 for surface coatings; and 0 005 mol/L CaCl 2 solution, 25℃ and pH 6 0 for surficial sediments). The Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb and Cd adsorption to the surface coatings and surficial sediments, and the component analyses of surface coatings and surficial sediments were also carried out. Correlation analyses between the maximum adsorption of Pb and Cd(Г max ) and the components in the surface coatings and surficial sediments suggested that there was a statistically significant trend for Pb and Cd adsorption(Г max ) to the surface coatings to increase with increasing in contents of Fe and Mn oxides in the surface coatings and surficial sediments. And the metal adsorption abilities of surface coatings were much stronger than those of surficial sediments, highlighting that in the same water, i.e. at the same pH and initial metal concentrations, the metals(such as lead and cadmium) in supernatant were feasible to be adsorbed by surface coatings than surficial sediments. The more importance of surface coatings than surficial sediments for adsorbing and cycling of heavy metals in aquatic environments was evidenced.
基金The National Natural Science Foundation of China under contract Nos 41606211,41276198,41406217 and 41306200the China Polar Environment Comprehensive Investigation and Assessment Programs under contract Nos Chinare-03-04 and Chinare-04-03+1 种基金the National Science Foundation for Post-doctoral Scientists of China under contract No.2016M591968the Scientific Research Fund of Second Institute of Oceanography,SOA under contract No.JG1502
文摘The content of organic carbon （OC） normalized to the specific surface area （SSA） of sediment is widely used to trace variations in OC loading （OC/SSA）. This study presents observations of OC/SSA of surface sediments collected in the Chukchi Sea, a typical Arctic marginal sea. Shelf sediments exhibit much higher OC/SSA values than slope sediments in the study area. Compared with OC/SSA values reported from the East Siberian Shelf and Mackenzie River, the slope sediments possess lower OC loading. This abrupt decrease in OC/SSA is mostly related to the lower primary production on slope as well as possible oxidization processes. The results of linear regression analysis between OC and SSA indicate a sedimentary source rock for the OC in the Chukchi Sea sediments. Moreover, shelf sediments with low SSA possess a larger rock OC fraction than slope sediments do. The dataset of the present study enables a more thorough understanding of regional OC cycling in the Chukchi Sea.
文摘The distributions of different forms of nitrogen in the surface sediments of the southern Huanghai Sea are different and affected by various factors. The contents of IEF-N, SOEF-N and TN gradually decrease eastward, and those of SAEF-N northward, while those of WAEF-N westward. Around the seaport of the old Huanghe (Yellow) River, the contents of both SOEF-N and TN are the highest. Among all the factors, the content of fine sediment is the predominant factor to affect the distributions of different forms of nitrogen. The contents of IEF-N, SOEF-N, and TN have visibly positive correlation with the content of fine sediments, and the correlative coefficient is 0.68, 0.58 and 0.71 respectively, showing that the contents of the three forms of nitrogen increase with those of fine sediments. The content of WAEF-N is related to that of fine sediments to a certain extent, with a correlative coefficient of 0.35; while the content of SAEF-N is not related to that of fine sediments, showing that the content of SAEF-N is not controlled by fine grain-size fractions of sediments. In addition, the distributions of different forms of nitrogen are also interacted one another, and the contents of IEF-N and SOEF-N are obviously affected by TN, while those of inorganic nitrogen (WAEF-N, SAEF-N and IEF-N) are not affected by SOEF-N and TN obviously, although they are interacted each other.
基金Supported by the National Natural Science Foundation of China(No.50879025)the Scientific Start-up Fund from North China Electric Power University, China(No.X60218)the National Basic Research Program of China(No.2004CB3418501).
文摘To reveal the relative contribution of the components, Fe, Mn oxides or organic materials（OMs） in the surficial sediments（SSs）, and the natural surface coating samples（NSCSs） to adsorbing atrazine（AT）, a selective chemical extraction technique was employed, to remove the different components, and the adsorption characteristics of AT on the SSs and the NSCSs were investigated. The observed adsorptions of AT on the original and extracted SSs and NSCSs were analyzed by nonlinear least squares fitting（NLSF） to estimate the relative contribution of the components. The results showed that the maximum adsorption of AT on the NSCSs was greater than that in the SSs, before and after extraction treatments, implying that the NSCSs were more dominant than the SSs for organic pollutant adsorption. It was also found that the Fe oxides, OMs, and residues in SSs（NSCSs） facilitated the adsorption of AT, but Mn oxides directly or indirectly restrained the interaction of AT with SSs（NSCSs） particles. The contribution of the Fe oxides to AT adsorption was more than that of OMs; the greatest contribution to AT adsorption on a molar basis was from the Fe oxides in the nonresidual fractions, indicating that the Fe oxides played an important role in controlling the environmental behavior of AT in an aquatic environment.
基金supported by the Science Foundation of Shanghai Municipal Commission of Science and Technology （Grant No.04DZ12030-3）, the National High-Technology Research and Development Program of China （Grant No.2005AA60101005）, and the Shanghai Leading Academic Discipline PProject （Grant No.T0105）Project （Grant No.T0105）.
文摘Nine elements （As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn） in sediment samples at 7 sites （Site 1-7） from Suzhou Creek in Shanghai were analyzed with the Community Bareau of Reference （BCR） （sequential extraction （SE）） protocol and simultaneously extracted metals （SEM）/acid volatile sulfide （AVS） procedure to assess the metal bioavailability and toxicology in this area. The results showed that the BCR extraction can be utilized as an additional tool with the AVS method for assessing the potential bioavailability and toxicity of metals in sediments. Pollution from S5 （Site 5） was more severe than from other sites, especially Pb, Cu and Zn. Among all the sites, more than 80% of the total concentration of Fe existed in the residual fraction, As, Cr, Mn also dominated in the residual fraction （more than 50%）. While Cd, Ni and Zn （more than 35%） were mainly in the non-stable phase. Cu had a strong affinity with oxidizable phase and Pb varied from site to site. The SEM/AVS ratio was less than one in these sediments and results implied that the majority of Zn and Ni （〉 40%） were bound to AVS. In contrast, Pb, Cu and Cd were little bound to AVS due to their low ration of SEM-Pb, Cu, Cd to corresponding total concentration and relatively high Dorewater concentration.
基金The National Natural Science Foundation of China under contract No.40606025the Program for New Century Excellent Talents in University,Ministry of Education under contract No.NCET-06-0446the "908" Program of State Oceanic Administration under contract No.908-ZC-II-03
文摘The concentration of zinc, chromium, cadmium, nickel, lead and copper was measured on both surface sediments and core sediments in the Shenzhen Bay. The average contents of all metals have exceeded the background values in the coastal zone of Guangdong Province. Cadmium is a heavy pollution matter which indicates a strong pollution level according to the ecological risk coefficient method. The ecological risk index of the whole area is 299 which belongs to middle and strong level. The area with strong pollution level is the near shore area closing to the inside of Shenzhen Bay, Shakou area is in the middle level while the weak pollution level occurs in Shenzhenhe Estuary according to ecological risk index. The four sediment cores can be divided into two parts based on lead-210 dating, sediments size analysis and economic development period in surrounding areas since 1950 with strong human intervention. The sediment size, deposition rate and human activities have positive relationship with the contents of heavy metals which directly impact the pollution level of heavy metals in sediments in Shenzhen Bay.
