Concentrations In Surface Sediments Research Articles

Distribution and characteristics of methylmercury in surface sediment in Minamata Bay

This study was carried out to evaluate the present-day chemical properties of methylmercury in surface sediment in Minamata Bay where a dredging project was completed 28years ago. Present-day sediment from Minamata Bay consists of sandy silt, and the average loss-on-ignition in surface sediment was 7.0±2.3%. The average methylmercury concentrations in the upper sediment layers were significantly higher than those in the lower sediment layers. Currently, the concentrations in sediments in Minamata Bay do not exceed the Japanese regulatory standard value for mercury. The average concentration of methylmercury in Minamata Bay surface sediment was 1.74±1.0ng/g on a dry weight basis (n=107). The methylmercury concentration in Minamata Bay surface sediment was almost 16 times higher than that in surface sediment from Isahaya Bay surface sediment, which was 0.11±0.045ng/g on a dry weight basis (n=5).

A REVIEW OF USE OF GIS FOR THE EVALUATION OF HEAVY METAL AND WATER QUALITY PARAMETERS IN THE CANAL DO CUNHA WATERSHED AND WEST OF THE GUANABARA BAY, RIO DE JANEIRO (BRAZIL)

As well as other sub-basins of the Guanabara Bay, the Canal do Cunha watershed, located in the Rio de Janeiro city, has suffered severe environmental degradation since the 50s, due to accelerated urban-industrial development. The fluvial dynamics has changed by the deforestation, landfill constructions, drainage and vale occupation. Canal do Cunha deliver wastewaters and sediments at the western side of Guanabara Bay. Contribute to the environmental degradation and has direct influence on the water quality indexes and heavy metal contamination at the western side of Guanabara Bay. This study intends to evaluate, through geoprocessing techniques, the spatial distribution of Lead (Pb), Zinc (Zn), dissolved oxygen (DO) and total phosphorus (total P) concentrations and pH values, using data provided by six monitoring stations of the Instituto Estadual do Ambiente – INEA (State Environmental Institute). This work allows to observe the influence of weather conditions on Pb and Zn concentrations in superficial waters and surface sediments and the behavior of DO, pH and total P of superficial waters before and after the implementation of the remediation program: Programa de Despoluicao da Baia de Guanabara (PDBG; Pollution Remediation Program of Guanabara Bay). Canal do Cunha flow has direct influence on the low quality indexes of water and contributes to the heavy metal contamination and environmental degradation of the western region of Guanabara Bay.

Distribution Characteristics of Polychlorinated Biphenyls in Sediments inside Jeju Harbor

In this paper, polychlorinated biphenyls (PCBs) were measured in surface sediments collected three times (June, October, December, 2013), inside Jeju Harbor as major harbors of Jeju Island. The concentration of PCBs inside Jeju Harbor was in the range of 1.62~4.45 (mean) ng/g on a dry weight basis and the levels were very low. In the analysis of PCBS homologue patterns, high-chlorinated PCB congeners were dominant in surface sediments inside Jeju Harbor, indicating that their sources were originated from shipping activity. In the relationships between PCBs concentrations and particle size (mud, sand and gravel) in surface sediments, PCBs concentrations were higher in the sediments with higher mud content, indicating that higher PCBs were distributed with increasing sediments of fine gradules. The PCBs concentrations in surface sediments in this study were very low, compared with ER-L (effect range-low) and TEL (threshold effects level) among sediment quality guideleines (SQGs) applied in foreign countries, such as USA, Canada, and Australia, etc), indicating that their biological effects on the bottom organisms in marine environment were expected to be very low.

Spatio-temporal distribution, source, and genotoxic potential of polycyclic aromatic hydrocarbons in estuarine and riverine sediments from southern India

In order to categorize the distribution, source, and effects of polycyclic aromatic hydrocarbons (PAHs) in aquatic systems of southern India, chemical and toxicological analyses were performed on surface and core sediments, collected from Adyar river, Cooum river, Ennore estuary, and Pulicat lake near Chennai city. The total PAH concentration in surface sediment ranged from 13 to 31,425ng/g with a mean value of 4320ng/g; the concentration was markedly higher in Cooum river compared to that at other sites. The historical PAH dissemination in core samples in the Cooum river, Ennore estuary, and Pulicat lake ranged from 30 to 31,425ng/g, from 8.6 to 910ng/g, and from 62 to 546ng/g, respectively. Surface sediments were predominantly contaminated with low molecular weight (LMW) PAHs. Historical profiles suggest that PAH contamination in the area is now greater than it had been in the past. PAH accumulation in Pulicat lake was distinct from that at other locations where high molecular weight (HMW) PAHs were predominant. DNA damage in HepG2 cells treated with sediment extracts from different locations showed a good correlation with their respective total PAH levels. Statistical analysis revealed that 3-ring and 4-ring PAHs may synergistically contribute to the genotoxic potency compared to others in sediments. The study also showed that a majority of PAHs in the study area indicated a petrogenic origin. Based on the enrichment and toxicological assessment of PAHs in sediments, Cooum river was shown to suffer the highest biological impairment among the studied water bodies.

A critical and comparative appraisal of polycyclic aromatic hydrocarbons in sediments and suspended particulate material from a large South American subtropical estuary

The Paranaguá Estuarine Complex (PEC) is an important socioeconomic estuary of the Brazilian coast that is influenced by the input of pollutants like polycyclic aromatic hydrocarbons (PAHs). Because of the apparent lack of comparative studies involving PAHs in different estuarine compartments, the aim of this study was to determine and compare PAH concentrations in surface sediment and suspended particulate material (SPM) in the PEC to evaluate their behaviour, compositions, sources and spatial distributions. The total PAH concentrations in the sediment ranged from 0.6 to 63.8 ng g−1 (dry weight), whereas in the SPM these concentrations ranged from 391 to 4164 ng g−1. Diagnostic ratios suggest distinct sources of PAHs to sediments (i.e., pyrolytic sources) and SPM (i.e., petrogenic sources such as vessel traffic). Thus, the recent introduction of PAHs is more clearly indicated in the SPM since oil related-compounds (e.g., alkyl-PAHs) remain present in similar concentrations. Further, this matrix may better reflect the current state of the environment at the time of sampling because of the absence of significant degradation.

Iron‐dependent anaerobic oxidation of methane in coastal surface sediments: Potential controls and impact

AbstractAnaerobic oxidation of methane (AOM) is an important process of methane (CH4) removal in sediments. Various studies suggest that AOM coupled to iron oxide (Fe(OH)3) reduction (Fe‐AOM) may complement sulfate‐driven AOM in CH4‐rich sediments. Here, we apply a transient reaction‐transport model to depth profiles of key porewater and sediment constituents for a site in the Bothnian Sea where Fe‐AOM has been suggested to occur. At the site, increased eutrophication has led to an upward shift of the sulfate‐methane transition zone, submerging Fe(OH)3 in a zone with high CH4 concentrations. Fe‐AOM is thought to lead to a strong accumulation of dissolved iron (Fe2+) in the porewater. Results of a sensitivity analysis identify three potential controls on the occurrence of Fe‐AOM in coastal surface sediments: (1) bottom‐water sulfate ( ) concentrations, (2) Fe(OH)3 availability, and (3) organic matter (OM) loading. In‐situ CH4 production is particularly sensitive to the OM loading and bottom‐water concentration, with higher concentrations significantly inhibiting methanogenesis and decreasing the potential rates of Fe‐AOM. We find that only environments with a low salinity and a relatively high Fe(OH)3 loading allow for Fe‐AOM to occur in surface sediments. This suggests that Fe‐AOM in surface sediments is restricted to areas with relatively high rates of sediment deposition such as estuaries and other nearshore systems. By enhancing porewater Fe2+ concentrations in surface sediments and the flux of Fe2+ from sediments to the overlying water, Fe‐AOM may contribute to the lateral transfer of iron (“iron shuttling”) from the coastal zone to deep basins.

Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China.

Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively.

Spatial distribution, environmental assessment and source identification of metals content in surface sediments of freshwater reservoir, Pakistan

Surface sediments were collected from different sites of a freshwater reservoir, Pakistan, and analyzed for eight metals (Cd, Co, Cr, Cu, Fe, Mn, Pb and Zn) using flame atomic absorption spectrometry. The estimated metals levels were found higher than other reported studies. The environmental indices including geoaccumulation index, enrichment factor and contamination factor identified Cd, Co, Pb and Zn as the priority pollutants of concern. Chromium, Cu and Mn were also found to be enriched in some areas. The pollution load index (≥1) indicated progressive deterioration of the sediments quality. Principal component and cluster analyses revealed that Cd, Co, Pb and Zn were mainly originated from agricultural activities, domestic wastes, road runoffs and recreational activities. Chromium, Cu, Fe and Mn were mainly derived from natural sources though Cr, Cu and Mn were partially contributed by human inputs. Based on spatial distribution, inlet and middle sites of the reservoir were found more contaminated. This study would drive urgent attention to develop preventive actions and remediation processes for aquatic system protection and future restoration of the reservoir.

Geochemical study of core sediments from Ennore Creek, North of Chennai, Tamil Nadu, India

The present study was carried out to investigate the down core variation of trace metal concentration in core samples of the study area. Six core samples were collected to assess the trace metal distribution in Ennore. All the core samples are dominated by coarse fraction of the sediments. In general, all the core samples have higher concentration of OM and are depleted in CaCO3 concentration. The highly inconsistent Mn concentration in surface sediments of the present study upholds the idea that oxyhydroxide flocs of Mn are transported laterally during saline bottom water inflow and deposited in quiescent parts of the estuary. Although the concentrations of Cr and Ni are both relatively higher, the influence on the former is anthropogenic, while that on the latter is more detrital. EF places Ennore under minimal to significant contamination of Cr and Cu. According to Pollution Load Index calculations, Ennore shows low-to-moderate degree of contamination.

Effects of Anthropogenic Activities on the Elemental Concentration in Surface Sediment of Oxbows

The Upper Tisza floodplain region provides a mosaic of aquatic habitats including a series of oxbows. Inorganic contaminants can accumulate in the sediment; thus, the sediment is good indicator of the contamination of these oxbows. Our aim was to explore the effects of anthropogenic activities on the concentration of elements and also to study the influence of vegetation types on the element in surface sediment of oxbows. We studied eight oxbows: two of them were protected, four of them were used for fishing and two of them were contaminated with domestic sewage. The following elements were measured with MP-AES in surface sediment: Al, Cr, Cu, Fe, Mn, Pb and Zn. The elemental concentration was compared to the toxicity classes of Environmental Protection Agency (EPA), and the assessment of the level of toxicity was based on this comparison. We found that studied oxbows were different from each other based on the elemental concentrations of sediment using canonical discriminant analysis and analysis of variance. Based on the elemental concentration in surface sediment of oxbows, separation was also found among vegetation types. But significant difference was not found in the concentrations of elements based on vegetation types. Our results demonstrated that the anthropogenic activities had remarkable effects on the elemental concentration of surface sediment in oxbows. Our findings suggest that the sediment is useful to assess the effects of anthropogenic activities on elemental concentrations of oxbows.

Effects of riverine suspended particulate matter on post-dredging metal re-contamination across the sediment-water interface.

Environmental dredging is often used in river mouth areas to remove heavy metals. However, following dredging, high levels of metal-adsorbed suspended particulate matter (SPM) originating from polluted inflowing rivers might adversely affect the sediment-water interface (SWI). Here, we conducted a 360-day-long experiment investigating whether the riverine SPM adversely affects dredging outcome in a bay area of Lake Chaohu, China. We found that the heavy metal concentrations in the post-dredging surface sediment increased to pre-dredging levels for all metals studied (As, Cd, Cr, Cu, Ni, Pb, and Zn) after the addition of SPM. In addition, the increased concentrations were mostly detected in the relatively bioavailable non-residual fractions. Of the metals studied, the rate of increase was the greatest for Zn and Cd (482.98% and 261.07%, respectively), mostly in the weak acid extractable fraction. These results were probably due to certain characteristics of SPM (fine grain size, and high concentrations of organic matter and heavy metals) and the good oxic conditions of the SWI. Furthermore, As was the only metal for which we observed an increasing trend of diffusive flux across the SWI. However, the flux was still significantly lower than that measured before dredging. In conclusion, the quantity and character of riverine metal-adsorbed SPM affect metal re-contamination across the post-dredging SWI, and this information should be incorporated into the management schemes of dredging projects dedicated to reducing metal contamination in similar areas.

Assessing trace metal pollution through high spatial resolution of surface sediments along the Tunis Gulf coast (southwestern Mediterranean).

Tunis Gulf (northern Tunisia, Mediterranean Sea) is of great economic importance due to its abundant fish resources. Rising urbanization and industrial development in the surrounding area have resulted in an increase in untreated effluents and domestic waste discharged into the gulf via its tributary streams. Metal (Cd, Pb, Hg, Cu, Zn, Fe, and Mn) and major element (Mg, Ca, Na, and K) concentrations were measured in the grain fine fraction <63 μm by atomic absorption spectrophotometry. Results showed varying spatial distribution patterns for metals, indicating complex origins and controlling factors such as anthropogenic activities. Sediment metal concentrations are ranked as follows: Fe > Mg > Zn > Mn > Pb > Cu > Cd > Hg. Metals tend to be concentrated in proximity to source points, suggesting that the mineral enrichment elements come from sewage of coastal towns and pollution from industrial dumps and located along local rivers, lagoons, and on the gulf shore itself. This study showed that trace metal and major element concentrations in surface sediments along the Tunis Gulf shores were lower than those found in other coastal areas of the Mediterranean Sea.

Different carbon sources affect PCB accumulation by marine bivalves

Pampean creeks were evaluated in the present study as potential land-based sources of PCB marine contamination. Different carbon and nitrogen sources from such creeks were analysed as boosters of PCB bioaccumulation by the filter feeder bivalve Brachidontes rodriguezii and grazer limpet Siphonaria lessoni. Carbon of different source than marine and anthropogenic nitrogen assimilated by organisms were estimated through their C and N isotopic composition. PCB concentration in surface sediments and mollusc samples ranged from 2.68 to 6.46 ng g−1 (wet weight) and from 1074 to 4583 ng g−1 lipid, respectively, reflecting a punctual source of PCB contamination related to a landfill area. Thus, despite the low flow of creeks, they should not be underestimated as contamination vectors to the marine environment. On the other hand, mussels PCB bioaccumulation was related with the carbon source uptake which highlights the importance to consider this factor when studying PCB distribution in organisms of coastal systems.

Bacterial wax esters in recent fluvial sediments

We investigated the molecular inventory of River Danube sediments and identified wax esters with 28–36 carbons, with C30, C31 and C32 homologs the most abundant. They consist of various combinations of n-, iso- and anteiso-aliphatic acid and alcohol moieties, with different isomer distributions for the esters with odd and even carbon numbers. The short chain length (C28–C36), high proportion of methyl moieties and presence of monounsaturated esters together suggest a bacterial origin for the wax esters. The concentration in surface sediments varied from 0 to 741μg/kg, being significantly enriched at locations with high nutrient concentration and high primary productivity. Cluster analysis of denaturing gradient gel electrophoresis (DGGE) band patterns revealed different bacterial communities in surface sediments from the stream and surface sediments from the reservoir. The concentration in a 70cm core of rapidly deposited sediments decreased significantly with depth, following first order kinetics, suggesting a loss of the esters within ca. 3years following burial and hence a low probability for preservation in the geological record. Wax esters in rivers have rarely been investigated; our results suggest that they represent a bacterial response to enhanced primary production, triggered by higher nutrient supply.

Evidence for Hydroxamate Siderophores and Other N-Containing Organic Compounds Controlling (239,240)Pu Immobilization and Remobilization in a Wetland Sediment.

Pu concentrations in wetland surface sediments collected downstream of a former nuclear processing facility in F-Area of the Savannah River Site (SRS), USA, were ∼2.5 times greater than those measured in the associated upland aquifer sediments; similarly, the Pu concentration solid/water ratios were orders of magnitude greater in the wetland than in the low-organic matter content aquifer soils. Sediment Pu concentrations were correlated to total organic carbon and total nitrogen contents and even more strongly to hydroxamate siderophore (HS) concentrations. The HS were detected in the particulate or colloidal phases of the sediments but not in the low molecular weight fractions (<1000 Da). Macromolecules which scavenged the majority of the potentially mobile Pu were further separated from the bulk mobile organic matter fraction ("water extract") via an isoelectric focusing experiment (IEF). An electrospray ionization Fourier-transform ion cyclotron resonance ultrahigh resolution mass spectrometry (ESI FTICR-MS) spectral comparison of the IEF extract and a siderophore standard (desferrioxamine; DFO) suggested the presence of HS functionalities in the IEF extract. This study suggests that while HS are a very minor component in the sediment particulate/colloidal fractions, their concentrations greatly exceed those of ambient Pu, and HS may play an especially important role in Pu immobilization/remobilization in wetland sediments.

곰소만 바지락(Ruditapes phillippinarum) 양식장 주변 퇴적물 내 유기물과 미량금속 분포특성

【Organic matter and trace metals were investigated in surface sediments of Gomso Bay, where there is dense Manila clam Ruditapes philippinarum farming activity, to evaluate contamination of sediments in intertidal shellfish farming area. We measured mean grain size (Mz), chemical oxygen demand (COD), ignition loss (IL), acid volatile sulfide (AVS), total organic carbon (TOC), and total nitrogen (TN), and trace metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) in intertidal and sublittoral sediments. The intertidal sediments were mainly composed of coarser sediments (sand, silty sand, and sandy silt), with Mz values ranging from 2.61 to 4.79 O. Mz and the content of organic matter in sediments were lower in the intertidal zone than in the sublittoral zone. The mean metal concentrations in surface sediments decreased in the order Fe > Mn > Zn > Cr > Pb > Cu > As > Cd > Hg. The metal concentrations in surface sediments showed a significant positive correlation with Mz and organic matter content, indicating that metal concentrations in the surface sediments of Gomso Bay are controlled by Mz and organic matter. The concentrations of organic matter and trace metals in the study region were lower than or similar to those in other intertidal zones in western coast and much lower than those reported in other shellfish farming areas in Korea. Our results suggest that intertidal Manila clam farming sediments from Gomso Bay are not contaminated by organic matter and trace metals.】

Distribution and Pollution Assessment of Trace Metals in the Surface Sediments around Farming Area of Jinhae Bay

Trace metals(As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb and Zn) concentrations in surface sediments of Jinhae bay in August of 2013 were measured to investigate the characteristics of trace metals distribution and to evaluate the metal pollution. Assessment for metal pollution was carried out using the sediment quality guidelines(SQGs) such as threshold effects level(TEL) and probable effects level(PEL) proposed by the ministry of onceans and fisheries(MOF) in Korea and geochemical assessment techniques(enrichment factor(EF) and geoaccumulation index ()). The mean concentration of trace metals in the sediments are as follows: 11.1 mg/kg for As, 0.52 mg/kg for Cd, 14.1 mg/kg for Co, 69.8 mg/kg for Cr, 57.2 mg/kg for Cu, 3.7 % for Fe, 0.064 mg/kg for Hg, 600 mg/kg for Mn, 40.1 mg/kg for Pb, 167.2 mg/kg for Zn. The spatial distributions of As, Co, Cr and Fe were not distinguished clearly in whole area. However, Cd, Hg, Pb and Zn were high in northern area of bay, and Cu and Mn were high in southeastern and eastern area of bay, respectively. The distribution pattern of trace metals, correlation matrix and R-mode factor analyses results revealed that the distribution of trace metals were mainly effected by the sediment grain size(Co, Cr and Fe), redox condition of sediments(Mn) and anthropogenic factors(As, Cd, Cu, Hg, Pb and Zn). Comparing the concentrations of several trace metals(As, Cd, Cr, Hg and Pb) with SQGs from Korea(TEL and PEL), the concentrations of Hg, Cd and Pb in sediment of northern area of bay were higher than TEL. EF and values of As, Cd, Cu, Hg, Mn, Pb and Zn showed that these metals in sediments are enriched by anthropogenic activities in some areas, and pollution status for Cd, Hg and Pb in northern area and Cu in southeastern area of bay were concerned about current level, although those for As, Mn and Zn were not.

Ammonia nitrogen adsorption and release characteristics of surface sediments in Dianchi Lake, China

To determine the ammonia nitrogen adsorption and release characteristics of surface sediments in Dianchi Lake, 36 surface sediment (0–10 cm) samples were collected in 2013. Results showed that compared with other lakes in China (e.g. Erhai Lake and Taihu Lake), Dianchi Lake had high levels of ammonia nitrogen (NH4 +–N) adsorption capacity, release rate and release capacity. The ammonia nitrogen release risk of Dianchi sediments was relatively high. Comparison of the equilibrium ammonium concentration (ENC 0) in surface sediments and the ammonium contents in the overlying water of Dianchi Lake indicated that ENC 0 was high for most lake sections. Therefore, the sediments of Dianchi Lake would be a pollution source, and ammonia nitrogen release risk was high because the surface sediments of Dianchi Lake were heavily contaminated with nitrogen. The total nitrogen (TN) and NH4 +–N contents of the sediments of Dianchi Lake greatly influenced the ammonia nitrogen adsorption–release process. Aside from TN, nitrogen fractions should also be studied when assessing pollutant release risk from lake sediments. NH4 +–N was the main fraction of nitrogen released from sediments, which was highly significant when evaluating sedimentary release capacity. The sedimentary release capacity and release potential of nitrogen provided important information to assess release risks.

Seasonal variation in element concentrations in surface sediments of three rivers with different pollution input in Serbia

Purpose The main objective of this study was to evaluate the concentrations and seasonal variations of trace elements in surface sediments of three major rivers in Serbia—the Danube, the Zapadna Morava (ZM), and the Južna Morava (JM)—according to sediment quality guidelines. The ZM and the JM create the Velika Morava River, one of the most important tributaries of the Danube, which has been characterized as a source of heavy metal pollution.

Flux and budget of BC in the continental shelf seas adjacent to Chinese high BC emission source regions

AbstractThis study conducted the first comprehensive investigation of sedimentary black carbon (BC) concentration, flux, and budget in the continental shelves of “Bohai Sea (BS) and Yellow Sea (YS),” based on measurements of BC in 191 surface sediments, 36 riverine water, and 2 seawater samples, as well as the reported data set of the atmospheric samples from seven coastal cities in the Bohai Rim. BC concentrations in these matrices were measured using the method of thermal/optical reflectance. The spatial distribution of the BC concentration in surface sediments was largely influenced by the regional hydrodynamic conditions, with high values mainly occurring in the central mud areas where fine‐grained particles (median diameters &gt; 6 Φ (i.e., &lt;0.0156 mm)) were deposited. The BC burial flux in the BS and YS ranged from 4 to 1100 µg/cm2 yr, and averaged 166 ± 200 µg/cm2 yr, which was within the range of burial fluxes reported in other continental shelf regimes. The area‐integrated sedimentary BC sink flux in the entire BS and YS was ~325 Gg/yr, and the BS alone contributed ~50% (~157 Gg/yr). The BC budget calculated in the BS showed that atmospheric deposition, riverine discharge, and import from the Northern Yellow Sea (NYS) each contributed ~51%, ~47%, and ~2%. Therefore, atmospheric deposition and riverine discharge dominated the total BC influx (~98%). Sequestration to bottom sediments was the major BC output pattern, accounting for ~88% of the input BC. Water exchange between the BS and the NYS was also an important BC transport route, with net BC transport from the BS to the NYS.