Fraction distribution and risk assessment of heavy metals and trace elements in sediments of Lake Uluabat

To examine the status and risk of heavy metal pollution, the distribution of As, Cd, Cr, Ni, and Pb in the sediment of Lake Uluabat was characterized. The present study used a four-stage method to assess the ecotoxicological effects of the heavy metal and trace elements fractions in the sediment of Lake Uluabat. Total Cr and Ni concentrations in the sediment were determined to have exceeded the severe effect level (SEL) limit values. The percentages of the variable fractions of Cr and Ni were below 10%. Because of this reason, they were not defined to have a high risk. The relationships among the physicochemical parameters, heavy metals and trace elements in water and sediment were determined statistically. Pb, Cd, and As in the water were found in relation with some of the fractions. Moreover, it was thought that the amounts of the elements of As releasing into the water might be increased due to their relations with the physicochemical parameters.     

Phosphorus speciation in the marine sediment of Kalpakkam coast,southeast coast of India

A study was carried out at Kalpakkam coast to find out the distribution of various fractions of phosphorus (P) in the marine sediment during pre-northeast monsoon period. Samples were collected from ten locations covering ~80 km² of the inner-shelf region. Sedimentary parameters such as sand, silt, clay, and organic carbon percentage were analyzed in order to find out their relation with various P fractions. The sediment was found to be predominantly sandy in nature with low silt and clay content. Among all the fractions (loosely bound (LoP), calcium bound (CaP), iron bound (FeP), aluminum bound (AlP), and organic (OP)), CaP fraction constituted the largest portion (68.7 %) followed by organic fraction (16.3 %). The bioavailable P fractions ranged from 5 to 44 % of the total P (TP) content. Relatively high LoP content was observed at the offshore locations with comparatively high mud percentage as compared with the near-shore locations. As FeP and AlP concentrations were directly proportional to the amount of fine-grain sediment, the low levels of these fractions found in this coastal area were therefore attributed to the sandy nature of the sediments. The order of abundance of the major forms of P in the surface sediments of Kalpakkam coast was as follows: CaP?>?OP?>?LoP?>?AlP?>?FeP.     

Arsenic and trace metals in river water and sediments from the southeast portion of the Iron Quadrangle, Brazil

The Iron Quadrangle has been one of the most important gold production regions in Brazil since the end of the seventeenth century. There, arsenic occurs in close association with sulfide-rich auriferous rocks. The most abundant sulfide minerals are pyrite and arsenopyrite, yet trace metal sulfides occur in subordinate phases as well. Historical mining activities have been responsible for the release of As and trace metals to both aquatic and terrestrial environments close to mining sites in the region. Therefore, this study was aimed to evaluate the distribution and mobility of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn in streams in the southeast portion of the Iron Quadrangle between the municipalities of Ouro Preto and Mariana, the oldest Brazilian Au mining province. Total concentrations of some trace metals and arsenic in water were determined. The four-stage sequential extraction procedure proposed by the commission of the European Communities Bureau of Reference (BCR) was used to investigate the distribution of these elements in stream sediments. Arsenic concentration in water was >10 ??g L^???1 (maximum limit permitted by Brazilian environmental regulations for water destined for human consumption) at all sampling sites, varying between 36.7 and 68.3 ??g L^???1. Sequential extraction in sediments showed high concentrations of As and trace metals associated with easily mobilized fractions.     

Relationships between trace elements in <Emphasis Type="Italic">Posidonia oceanica</Emphasis> shoots and in sediment fractions along Latium coasts (northwestern Mediterranean Sea)

The Mediterranean endemic seagrass Posidonia oceanica is widely used as a sensitive bioindicator of trace elements (TEs) in the coastal environment. Therefore, a bulk of data exist on TE levels from impacted versus unpolluted sites while only recent studies started comparing TE accumulation in plant compartments versus both water column and sediment characteristics. In this study, six TEs (As, Cd, Cr, Cu, Ni, Pb) were analyzed in P. oceanica shoots related to depth (?10 and ?20 m) and to TE concentrations in the different grain size fractions of the sediment, from two Sites of Community interest (SIC) in the central Tyrrhenian Sea. TE concentrations in both shoots and sediment were generally low, except for Cr. Cu was the only element showing significantly different concentrations at the two sites while As differed significantly between samples taken at different depths. TE concentrations in the unsieved sediment were found uncorrelated to TEs in shoots except for the important nutrient Cu (positive correlation). The finest sediment fractions were enriched in TEs and significantly correlated to Cd, Cr, Cu, and Ni concentrations in the shoots.     

Trace elements and organochlorines in the shoalgrass community of the lower Laguna Madre,Texas

Our objectives were to measure concentrations of seven trace elements and 14 organochlorine compounds in sediment and biota of the shoalgrass (Halodule wrightii) community of the lower Laguna Madre of south Texas and to determine whether chemicals associated with agriculture (e.g. mercury, arsenic, selenium, organochlorine pesticides) were highest near agricultural drainages. Arsenic, mercury, selenium, lead, cadmium, and organochlorines were generally at background concentrations throughout the lower Laguna Madre. Nickel and chromium concentrations were exceptionally high in shrimp and pinfish (Lagodon rhomboides), which is difficult to explain because of no known anthropogenic sources for these trace elements. For sediment and blue crabs (Callinectes sapidus), mercury was highest near agricultural drainages. Also, DDE was more frequently detected in blue crabs near agricultural drainages than farther away. In contrast, selenium concentrations did not differ among collecting sites and arsenic concentrations were lowest in shoalgrass, blue crabs, and brown shrimp (Penaeus aztecus) near agricultural drainages.     

Sand as a relevant fraction in geochemical studies in intertidal environments

Soil and sediment samples from several intertidal environment exposed to different types of contamination were studied to investigate the importance of grain size in relation to the capacity of the substrates to retain trace metals. The unfractionated samples (referred to as bulk samples) were separated into the following grain/size fractions: fine–coarse sand (2?0.100 mm), very fine sand (0.100?0.050 mm), silt (0.050?0.002 mm), and clay (0.002 mm). The sample into its fractions was carried out was in a glove box under high-purity N₂ atmosphere in order to minimize any alterations to the samples. The bulk samples were characterized in terms of physicochemical properties such as pH, redox potential, and grain size. The total organic carbon (TOC), total sulfur (S), iron (Fe) pyrite, Fe, and manganese (Mn), and trace metals lead (Pb), mercury (Hg), chromium (Cr), and nickel (Ni) were analyzed in the bulk samples and in each fraction. The sand fractions were also examined by scanning electron microscopy (SEM). Comparisons of the above parameters were made between fractions and between each fraction and the corresponding bulk sample. The fine–coarse sand fraction contained high levels of the primary elements of the geochemical processes that occur in marine sedimentary environments such as TOC, total Fe, Mn, and S. The net concentrations of these four elements were higher in the fine-coarse sand fraction than in the very fine sand fraction and were similar to the net concentrations in the silt and clay fractions. Detailed SEM analysis of the sand coarse fraction revealed the presence of Fe and aluminum oxyhydroxide coatings in the oxic layers, whereas the framboidal pyrites and coatings observed in the anoxic layers were Fe sulfides. The presence of the various coatings explains why the trace metal concentrations in the sand fine–coarse fraction were similar to those in the clay fraction and higher than those in the very fine sand fraction. The present results highlight the importance of the sand fraction, which is generally disregarded in geochemical and environmental studies of sedimentary layers.     

Changes of carbon,nitrogen, phosphorous,and potassium content during storage of vermicomposts prepared from different substrates

The study was conducted to determine the optimum storage time for vermicompost without significant loss of nutrients; nitrogen (N), phosphorous (P), and potassium (K). Cattle manure, paddy straw, municipal solid wastes, and fly ash were used for vermicompost preparations. The dynamics of N, P, and K in the vermicomposts were studied during 180 days of incubation at 28–32 °C. In general, N concentration increased in the first 90–105 days of incubation and then gradually decreased until the 180th day while P and K concentrations steadily decreased over the length of the study, with the rate of loss leveling off after 150 days. The rate of nutrient loss was directly related to the initial level, decreasing the fastest for the nutrients with the highest initial concentrations. Optimum storage times were substrate and N dependent.     

Concentrations of Cu, Fe, Mn, and Zn in tropical soils amended with sewage sludge and composted sewage sludge

Sewage sludge may be used as an agricultural fertilizer, but the practice has been criticized because sludge may contain trace elements and pathogens. The aim of this study was to compare the effectiveness of total and pseudototal extractants of Cu, Fe, Mn, and Zn, and to compare the results with the bioavailable concentrations of these elements to maize and sugarcane in a soil that was amended with sewage sludge for 13 consecutive years and in a separate soil that was amended a single time with sewage sludge and composted sewage sludge. The 13-year amendment experiment involved 3 rates of sludge (5, 10, and 20 t ha^?1). The one-time amendment experiment involved treatments reflecting 50, 100, and 200 % of values stipulated by current legislation. The metal concentrations extracted by aqua regia (AR) were more similar to those obtained by Environmental Protection Agency (EPA) 3052 than to those obtained by EPA3051, and the strongest correlation was observed between pseudo(total) concentrations extracted by AR and EPA3052 and bioavailable concentrations obtained by Mehlich III. An effect of sewage sludge amendment on the concentrations of heavy metals was only observed in samples from the 13-year experiment.     

Mobility and ecological risk assessment of trace metals in polluted estuarine sediments using a sequential extraction scheme

The three-stage sequential extraction procedure for the fractionation of Cd, Cr, Cu, Ni, Pb, and Zn, proposed by the Commission of the European Communities Bureau of Reference, was applied to sediment five samples collected from the Sal estuary, Sergipe State, northeast Brazil, in September 2009. The method showed satisfactory recoveries, detection limits, and standard deviations for determinations of trace metals in the sediments. Cd and Pb were the metals most prevalent in the bioavailable fractions (carbonates, Fe and Mn oxides, organic matter, and sulfides), while Ni, Zn, Cu, and Cr showed higher percentages in the inert fraction. The order of mobility of the metals was Cd (66 %) > Pb (65 %) > Zn (59 %) > Ni (57 %) = Cr (57 %) > Cu (56 %). Possible toxicity related to these metals was examined using the risk assessment code, and by comparing the chemical data with sediment quality guideline ERL-ERM values. Results obtained using the two methods were in agreement, and showed low to medium risk for all metals, indicating that adverse effects on aquatic biota should rarely occur.     

Trace metal speciation and contamination in an intertidal estuary

An analysis of the geochemical distribution of selected trace metals among various geochemical phases of the sediments in the Tees estuary was carried out using a sequential extraction technique and Differential Stripping Voltammetry. The sediments of the estuary are mainly organic rich clay silts and metal concentrations exceed those in the water column. Speciation results show that contamination of the estuary is mainly from anthropogenic sources. Pb and Zn are associated with the reducible, residual and oxidisable fractions. The speciation pattern of Cd was similar to those of lead and zinc. However there were also some exchangeable and bound to carbonate fractions although these were less significant. Cu is largely associated with the oxidisable and residual fractions, with insignificant bound to carbonate, exchangeable and reducible fractions. The most bioavailable forms of the metals are the free inorganic ions. Total metal concentrations in the estuary display a downward trend since the 1970s.     

Speciation of Trace Metals in Coastal Sediments of El-Mex Bay South Mediterranean Sea–West of Alexandria (Egypt)

Sediments of El-Mex Bay estuary on the southern Mediterranean Sea have been analyzed for trace metals after sediment fractionation by sequential leaching. A sequential extraction procedure was applied to identify forms of Mn, Cu, Cd, Cr, Zn and Fe. The five steps of the sequential extraction procedure partitioned metals into: CH₃COONH₄ extractable (F1); NaOAC carbonate extractable (F2); NH₂OH.HCl/CH₃COOH reducible extractable (F3); H₂O₂–HNO₃ organic extractable (F4) and NHO₃/HClO₄/HF acid soluble residue (F5). Extracted concentrations of trace metals analyzed after all five steps, were found to be (μg/g) for Mn: 1930.2, Cu: 165.3, Cd: 60.9, Cr: 386.3, Zn: 2351.3 and Fe: 10895. Most of elements were found in reducible fraction except Fe found in acid soluble residue, characterizing stable compounds in sediments. Labile (non-residual) fractions of trace elements (sum of the first four fractions) were analyzed because they are more bioavailable than the residual amount. Correlation analysis was used to understand and visualize the associations between the labile fractions of trace metals and certain forms, since Fe-and Mn-oxides play an important role in trace metals sorption within aquatic systems, especially within El-Mex Bay sediments that characterized by varying metal bioavailability.     

Ecotoxicological impact assessment of some heavy metals and their distribution in some fractions of mangrove sediments from Red Sea, Egypt

The total and fraction concentrations of heavy metals (Mn, Cu, Ni, Pb, Co, and Cd) were analyzed in some sediment fractions (Φ2, Φ3, Φ4, Φ5) of selected mangrove ecosystems collected from the Egyptian Red Sea shoreline. The results revealed that manganese had the highest mean value (133?±?97 mg/kg) followed by copper (49.9?±?46.0 mg/kg), nickel (28.1?±?11.8 mg/kg), lead (19?±?13 mg/kg), cobalt (6.7?±?4.0 mg/kg), and cadmium (3.327?±?1.280 mg/kg). The concentrations of heavy metals in the different sediment fractions showed that there was a preferential accumulation of Cu, Co, Mn, and to a lesser degree Cd in the silt and clay fractions rather than in the sand-sized. The sediment quality was performed by using some sediment quality guidelines. Additionally, the contamination and the risk assessment of these heavy metals were achieved by different methods including, potential ecological risk index, contamination factor, pollution load index, and geoaccumulation index. According to the Sediment Quality Guidelines comparisons, the concentrations of Mn and Pb were low and showed no possibility of detrimental effects on the local environment. The levels of Cu and Ni were high, however, could not be considered to present serious threat to the mangrove ecosystem. The data showed that the mangrove ecosystems were affected by the Cd risk.     

Comparative on Causes and Accumulation of Selenium in the Tree-rings Ambient High-selenium Coal Combustion Area from Yutangba, Hubei, China

Toxic trace elements emitted during coal combustion are the main sources of air pollution. They are released into the atmosphere mainly in the forms of fine ash, smoke and flue, and thus adversely affect plant, animal and human health. Selenium is one of toxic and the most volatile in coal. Large amount of atmospheric emission of selenium, as well as selenium present and scrubber stockpiles in ash may create serious environmental problems. In the paper, on the basis of investigating the abundance and distribution of selenium in plant-rings during recent 20 years, the bioaccumulation of selenium is explained that selenium in plant, which were collected from the village of selenium-rich coal combustion, is much higher than that in plants collected away from the village of selenium-rich coal combustion. The main origins of selenium are selenium-rich coal combustion and high-selenium rock weathered. The selenium recycle by food chain and selenium will accumulate and redistribute in environments.     

A regional inventory and monitoring setup to evaluate bark peeling damage by red deer (Cervus elaphus) in coniferous plantations in Southern Belgium

Sediment phosphorus (P) fractions and sorption characteristics and P release from intact sediment cores of Baiyangdian Lake in North China in spring 2009 were investigated. Results of chemical fractionation showed that total P (TP) content in sediment ranged from 443 to 611 mg kg(?-1). Of the P fractions including inorganic P (IP) and organic P (OP), IP was a dominant component of TP and present in the form of P bounded to calcium (Ca-P) while the bioavailable P content bounded to Al, Fe, and Mn oxides and hydroxides (Fe/Al-P) varied from 14 to 102 mg kg(?-1). The batch experiments showed that the sediments had appreciable maximum P adsorption capacity from 141.86 to 377.37 mg kg(?-1). However, the zero P equilibrium concentration (C?(eq))in most sampling sites was larger than the P concentration in water column. Accordingly, the sediments from those sampling sites would release P into the overlying water at the positive P flux rates as a P release source. Significant positive correlation between P flux rates and Fe/Al-P revealed that the sediment P release would mainly originate from the bioavailable P fraction. It is evident that the inherent phosphorus present in lake sediments would be a major threat to the water quality and ecosystem reservation in Baiyangdian lake.     

Behavior study of trace elements in pulverized lignite, bottom ash, and fly ash of Amyntaio power station, Greece

The Kozani–Ptolemais–Amyntaio basin constitutes the principal coal field of Greece. Approximately 50 % of the total power production of Greece is generated by five power stations operating in the area. Lignite samples, together with the corresponding fly ash and bottom ash were collected, over a period of 3 months, from the power plant of Amyntaio and analyzed for their content in 16 trace elements. The results indicate that Y, Nb, U, Rb, Zr, Ni, Pb, Ba, Zn, Sr, Cu, and Th demonstrate an organic affinity during the combustion of lignite, while V has an inorganic affinity. Three elements (Co, Cr, and Sc) show an intermediate affinity.     

A complex investigation of the extent of pollution in sediments of the Sava River. Part 1: Selected elements

The Sava River is the biggest tributary to the Danube River. As a part of the 6th FW EU project, Sava River Basin: Sustainable Use, Management and Protection of Resources (SARIB), ecological status of sediments was investigated. In order to assess the geographical distribution in sediment contamination of the Sava River, inorganic and persistent organic pollutants were analyzed in sediments at 20 selected sampling sites along the Sava River from its spring to its outfall into the Danube River. For comparability of data to other river basins the sediment fraction below 63 μm was studied. Due to complexity of the work performed, the results are published separately (“Part I: Selected elements” and “Part II: Persistent organic pollutants”). In the present study, the extent of pollution was estimated by determination of the total element concentrations and by the identification of the most hazardous highly mobile element fractions and anthropogenic inputs of elements to sediments. To assess the mobile metal fraction extraction in 0.11 mol L^???1, acetic acid was performed (first step of the Community Bureau of Reference extraction procedure), while anthropogenic inputs of elements were estimated on the basis of normalization to aluminum (Al) concentration. According to the Water Framework Directive, the following elements were investigated in sediments: cadmium (Cd), lead (Pb), nickel (Ni), and mercury (Hg). Furthermore, copper (Cu), zinc (Zn), chromium (Cr), arsenic (As), and phosphorous (P) were determined. The analyses of sediments demonstrated slightly elevated values for Hg, Cr, and Ni in industrially exposed sites (concentrations up to 0.6, 380, and 210 mg kg^???1, respectively). However, the latter two elements exist in sparingly soluble forms and therefore do not represent an environmental burden. P concentrations were found in elevated concentrations at agricultural areas and big cities (up to 1,000 mg kg^???1).     

Risk assessment of trace metals in an extreme environment sediment: shallow,hypersaline, alkaline,and industrial Lake Acıgöl,Denizli, Turkey

The major and trace element component of 48 recent sediment samples in three distinct intervals (0–10, 10–20, and 20–30 cm) from Lake Ac?göl is described to present the current contamination levels and grift structure of detrital and evaporate mineral patterns of these sediments in this extreme saline environment. The spatial and vertical concentrations of major oxides were not uniform in the each subsurface interval. However, similar spatial distribution patterns were observed for some major element couples, due mainly to the detrital and evaporate origin of these elements. A sequential extraction procedure including five distinct steps was also performed to determine the different bonds of trace elements in the <?60-μ particulate size of recent sediments. Eleven trace elements (Ni, Fe, Cd, Pb, Cu, Zn, As, Co, Cr, Al and Mn) in nine surface and subsurface sediment samples were analyzed with chemical partitioning procedures to determine the trace element percentage loads in these different sequential extraction phases. The obtained accuracy values via comparison of the bulk trace metal loads with the total loads of five extraction steps were satisfying for the Ni, Fe, Cd, Zn, and Co. While, bulk analysis results of the Cu, Ni, and V elements have good correlation with total organic matter, organic fraction of sequential extraction characterized by Cu, As, Cd, and Pb. Shallow Lake Ac?göl sediment is characteristic with two different redox layer a) oxic upper level sediments, where trace metals are mobilized, b) reduced subsurface level, where the trace metals are precipitated.     

Speciation of As(III) and As(V) in water and sediment using reverse-phase ion-pair high-performance liquid chromatography-neutron activation analysis (HPLC-NAA)

Total As content and the As species distribution in water and sediments from the Kwabrafo stream, a major water body draining the Obuasi gold mining community in southwestern Ghana, have been investigated. Total As content was determined by instrumental neutron activation analysis (INAA). Ion-pair reverse phase high-performance liquid chromatography-neutron activation analysis (HPLC-NAA) was used for speciation of As species. Solid phase extraction with phosphate buffer was used to extract soluble As species from lyophilized sediment. The mass balance after phosphate extraction of soluble As species in sediment varied from 89 to 96 %. Compositionally appropriate reference material International Atomic Energy Agency (IAEA)-Lake Sediment (SL)-1 was used to check the validity of INAA method for total As determination. The measured values are in good agreement with the IAEA recommended value and also within the 95 % confidence interval. The accuracy of the measurement in terms of relative deviation from the IAEA recommended value was ±0.83 %. “In-house” prepared As(III) and As(V) standards were used to validate the HPLC-INAA method used for the As species determination. Total As concentration in the water samples ranged from 1.15 to 9.20 mg/L. As(III) species in water varied from 0.13 to 0.7 mg/L, while As(V) species varied from 0.79 to 3.85 mg/L. Total As content in sediment ranged from 2,134 to 3,596 mg/kg dry mass. The levels of As(III) and As(V) species in the sediment ranges from 138 to 506 mg/kg dry mass and 156 to 385 mg/kg dry mass, respectively.     

Trace element concentration and speciation in selected urban soils in New York City

A long history of urbanization and industrialization has affected trace elements in New York City (NYC) soils. Selected NYC pedons were analyzed by aqua regia microwave digestion and sequential chemical extraction as follows: water soluble (WS); exchangeable (EX); specifically sorbed/carbonate bound (SS/CAR); oxide-bound (OX); organic/sulfide bound (OM/S). Soils showed a range in properties (e.g., pH 3.9 to 7.4). Sum of total extractable (SUM_TE) trace elements was higher in NYC parks compared to Bronx River watershed sites. NYC surface horizons showed higher total extractable (TE) levels compared to US non-anthropogenic soils. TE levels increased over 10 year in some of the relatively undisturbed and mostly wooded park sites. Surface horizons of park sites with long-term anthropogenic inputs showed elevated TE levels vs. subsurface horizons. Conversely, some Bronx River watershed soils showed increased concentrations with depth, reflective of their formation in a thick mantle of construction debris increasing with depth and intermingled with anthrotransported soil materials. Short-range variability was evident in primary pedons and satellite samples (e.g., Pb 253?±?143 mg/kg). Long-range variability was indicated by Pb_TE (348 versus 156 mg/kg) and Hg_TE (1 versus 0.3 mg/kg) concentrations varying several-fold in the same soil but in different geographic locations. Relative predominance of fractions: RES (37 %)?>?SS/CAR (22 %)?>?OX (20 %)?>?OM/S (10 %)?>?EX (7 %)?>?WS (4 %). WS and EX fractions were greatest for Hg (7 %) and Cd (14 %), respectively. RES was predominant fraction for Co, Cr, Ni, and Zn (41 to 51 %); SS/CAR for Cd and Pb (40 and 63 %); OM/S for Cu and Hg (36 and 37 %); and OX for As (59 %).     

Effects of leachant temperature and pH on leachability of metals from fly ash. A case study: Can thermal power plant, province of Canakkale, Turkey

Lignite powered electric generation plants result in increasing environmental problems associated with gaseous emissions and the disposal of ash residues. Especially, low quality coals with high ash content cause enormous quantities of both gaseous and solid fly ash emissions. The main problem is related to the disposal of fly ash, which, in many cases, contains heavy metals. It is known that toxic trace metals may leach when fly ash is in contact with water. In this study, fly ash samples obtained from the thermal power plant in the town of Can in Turkey were investigated for leachability of metals under different acidic and temperature conditions. The experimental results show that a decrease in pH of the leachant favors the extraction of metal ions from fly ash. A significant increase in the extraction of arsenic, cadmium, chromium, zinc, lead, mercury, and selenium ions from the ash is attributed to the instability of the mineral phases. These heavy metals concentrations increase with respect to increasing acidic conditions and temperature. Peak concentrations, in general, were found at around 30°C.