Search

Bioremediation is used to reduce the effect of industrial and agricultural pollutants in contaminated soil, which in turn leads to removing and reducing the toxicity of heavy metals polluting the soil. This study evaluates the possibility of using the currant plant to reduce the concentration of heavy metals in some polluted soils within different locations in Babil Governorate. Soil samples were taken from four sites, representing agricultural soil irrigated with wastewater, soil adjacent to a brick factory, and soil adjacent to a sterile drinking water factory, in addition to a control sample, which is agricultural soil irrigated with river water. The soil samples were analyzed Soil to determine the general characteristics and concentration of the total heavy elements represented by lead (Pb), cobalt (Co), nickel (Ni) and zinc (Zn). Then the pollution standards for the soil and plants were calculated and the averages were compared using the least significant difference test at the 5% level. The results showed that nickel and Zinc were significantly superior to the total content of elements in the soil, and the lowest values were for Cobalt. The values of the contamination factor for the soil showed that nickel was in first place, followed by Cobalt, then Lead and Zinc. As for the pollution load index (PLI), its value was highest in the agricultural soils adjacent to the bricks factory, while the values of the accumulation index (Igeo) indicated that the Nickel element had surpassed on Cobalt, Zinc and lead. The concentration of elements in the plant shoots indicated a superiority in Zinc and Cobalt, while Nickel and Lead were superior in the root system. The BCF index was less than one for all sites except agricultural soils irrigated with river water, and the site transfer factor TF values were greater than 1 In the elements Cobalt and Zinc. The results also showed that the currant plant is one of the plants that accumulates the heavy metals because it does not show negative symptoms during its growth and thus the possibility of using it to reduce the risk of heavy elements in the soil. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the concentration of the heavy metals (Co, Cd, Cr, Cu, Ni, Pb, and Zn) and their ecological risk in soils adjacent to the power generators of Ramadi city, Iraq. The soil samples were collected from a depth of 20cm. The obtained results showed that the mean concentrations of heavy metals (HMs) are ranked as in the following order: Cr (360.90mg/kg) > Ni (283.65mg/kg) > Zn (190.96mg/kg) > Pb (130.75 mg/kg) > Cu (36.54 mg/kg) > Co (16.62 mg/kg) > Cd (2.55 mg/kg). The mean values of HMs concentration exceed the international guidelines. The result of correlation matrix analysis at P  0.05 showed significant correlations between the concentrations of HMs. These correlations are interpreted in the context of a common source of pollution and/or common origin. Results of the potential ecological risk factor assessment of metal i (Ei r) in soil adjacent to the power generators of Ramadi city showed that the Ei r values take the following descending order: Ni (354.56, very severe) > Cd (255.31, severe), Co (207.77, severe) > Zn (88.69, heavy) > Cu (25.73, light) > Cr (17.43, light) > Pb (12.0, light). The potential ecological risk index (RI) values are classified as severe ecological risk for all studied heavy metals. This study provides the environmental protection managers and decision-makers with important information about the risk of using electrical generators in residential neighborhoods. [ABSTRACT FROM AUTHOR]

Heavy metal contamination status of bottom sediments of two lagoons was compared by the employment of Enrichment Factor (EF) analysis for Iron (Fe), Manganese (Mn), Cupper (Cu), Lead (Pb), Chromium (Cr), Nickel (Ni), Silver (Ag), Zinc (Zn) and Mercury (Hg). Kpeshie Lagoon recorded enrichment (EF = 1) for Cd, Pb, Ag, Hg and Zn, whilst Muni Lagoon recorded enrichment for Cd, Mn, Ag, Hg and Zn as metals of anthropogenic influence. Kpeshie, situated in a highly urbanized area, has 75% spatial distribution of Pb enrichment. The assessment shows that Ag and Hg are the most enriched metals in the sediments of both Lagoons, reaching extremely severe levels. Only Mn showed statistically significant difference in mean concentration of metals for both Lagoons. Pearson correlation matrix indicated that Pb had a strong relation with Ag, Hg and Zn (r = 0.956; p < 0.05) which is significant in Kpeshie. It also had a strong association with Ag and Hg but not with Zn (r = 0.240) in the Muni. The study clearly delineates Pb as a pollutant that designates the urban status of Kpeshie. Its associated metals; Ag, Hg and Zn which may be coming from a common source are from industrialized zones. [ABSTRACT FROM AUTHOR]

Due to rapid urbanization and industrialization that occurred in Al- Muthanna province in southeastern Iraq during the last decade, pollutants such as heavy metals were emitted into the environment and became a serious threat to human health. Environmental pollution could be caused by different types of pollutants, which come from different sources. This study aims to assess the environmental magnetism efficiency for heavy metal pollution assessment using the magnetic susceptibility technique which became a more rapid and cost-effective compared to conventional methods. Increasing heavy metal contents in soils causes an increase in the magnetic mineral concentration. The study area is located in Al- Muthanna province, southeast of Iraq, and contains three cement plants, an oil refinery, bricks factories, and power plants. Fifty topsoil and subsoil samples (0-50 cm depth) were collected from five sites; Al- Jinoob cement plant (one site), Samawa oil refinery (two sites) and Al- Muthanna cement plant (two sites). In this study, magnetic properties of samples in vertical sections and levels of heavy metal elements; of selected samples from regions with different geological settings were compared. The heavy metals analysis included chromium (Cu), iron (Fe), nickel (Ni), copper (Cu), Arsenic (As) and lead (Pb), which could give indications of heavy metal pollution in soil. The highest magnetic susceptibility value (65.23 x10-8 m3kg-1) was recorded in Al-Muthanna cement plant (TSL-4) and the highest Cu concentration (602.57 ppm) was also recorded in Al- Muthanna cement plant (TSL-5-3). The results of magnetic properties show the dominance of coarse magnetite, which is supposed to have originated from pedogenic particles in natural soils, causing the positive correlation between magnetic susceptibility (χ) and anhysteretic remanent magnetisation (ARM). According to the results of frequency dependent susceptibility ratio (κfd%), the magnetic particles showed an admixture of multi-domain and pseudo-single domain behaviour. Magnetic susceptibility and heavy metal analyses results indicated emissions from nearby industrial plants. X-ray fluorescence (XRF) was carried out for heavy metal analyses which supported our results. Results of this study demonstrate the suitability of applying magnetic techniques for assessing environmental situations. [ABSTRACT FROM AUTHOR]

Heavy metal sedimentation of acid mine waste (AMW) with sulphate reducing bacteria (SRB) isolated from estuary dam ecosystem sediment of Denpasar was studied in detail. Three isolates of SRB namely DPS 1703, DPS 1705 and DPS 1711 were selected. The bacterium was straight rods, motile, spore-forming and able to grow in simple or defined media. According to physiology and biochemical characterization, the isolates were identified as Desulfotomaculum orientis. The bacterium survived at pH 3 and showed abundant growth at pH 4.0 to 7.0. Reactor with SRB consortium was applied to precipitate heavy metal ions from acid mine waste. The experiment used compost as a simple organic matter source. Growth of SRB in the anaerobic reactor significantly reduced sulphate to sulfide (92.77-94.52%) and increased the pH from 3 to 6.2-6.7. Soluble heavy metal ions reduced to the much less mobile or insoluble state. The efficiency achieved for Cd(II) was 85.45-90.00%, Pb(II) 95.10-97.95%, Mn(II) 99.79-99.89%, Zn(II) 99.87-99.90%, Cu(II) 99.23-99.43% and Fe(III) 99.93-99.96%. [ABSTRACT FROM AUTHOR]

Abstract Because of its high adsorption capacity, biochar has been used to stabilize metals when remediating contaminated soils; to date, however, it has seldom been used to remediate contaminated sediment. A biochar was used as a stabilization agent to remediate Cu- and Pb-contaminated sediments, collected from three locations in or close to Beijing. The sediments were mixed with a palm sawdust gasified biochar at a range of weight ratios (2.5%, 5%, and 10%) and incubated for 10, 30, or 60 days. The performance of the different treatments and the heavy metal fractions in the sediments were assessed using four extraction methods, including diffusive gradients in thin films, the porewater concentration, a sequential extraction, and the toxicity characteristic leaching procedure. The results showed that biochar could enhance the stability of heavy metals in contaminated sediments. The degree of stability increased as both the dose of biochar and the incubation time increased. The sediment pH and the morphology of the metal crystals adsorbed onto the biochar changed as the contact time increased. Our results showed that adsorption, metal crystallization, and the pH were the main controls on the stabilization of metals in contaminated sediment by biochar. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Human health risks of five different heavy metals were assessed in nine typical areas in Asia, Europe, and Africa. The geoaccumulation index (Igeo) of arsenic (As) in Hyderabad (HB), cadmium (Cd) in Veles (VL), and lead (Pb) in Murcia (MC) were found to be 5, indicating extreme contamination. This is related to their high concentrations in soil. The concentration of As in wheat in Niger Delta (ND) and European Union (EU) areas were 3.3 and 2.55 mg/kg, which were 22 and 17 times respectively of the World Health Organization (WHO)/Food and Agriculture Organization (FAO) criteria. In general, the concentrations of heavy metals in wheats were higher than those in corns, indicating that heavy metals were easier to accumulate in wheats than in corns. The human risks induced by the carcinogenic metals As and Cd were much higher than those induced by noncarcinogenic metals in different exposure ways. The human health risks of heavy metals in different exposure ways were Rw-ing > Rc-ing > Rs-ing > Rs-der > Rs-inh. The human health risks induced by wheat ingestion for adults and children accounted for 67.75–97.52% and 69.52–98.04%, respectively, of the total human health risks. The total human health risks in the VL and MC areas were 1.58 × 10−4 a−1 and 1.3 × 10−4 a−1 for adults and 1.14 × 10−4 a−1 and 9.47 × 10−5 a−1 for children, respectively, which were significantly high according to the Environmental Protection Agency and International Commission on Radiological Protection. The ranking of the total human health risks in different areas were RVL > RMC > RND > REU > RHB > RKY > RTB > RMLV > RNHM. The total human health risks of adults were higher than those of children. [ABSTRACT FROM AUTHOR]

The leaf-shredding crustacean Hyalella azteca, which is indigenous to Northern and Central America, is used to assess environmental risks associated with (metal-)contaminated sediments and to propose sediment quality standards also in Europe. Yet, it is unknown if H. azteca is protective for European crustacean shredders. We thus compared the sensitivity of H. azteca with that of the European species Asellus aquaticus and Gammarus fossarum towards copper- and cadmium-contaminated sediments (prepared according to OECD 218) under laboratory conditions employing mortality and leaf consumption as endpoints. H. azteca either reacted approximately fourfold more sensitive than the most tolerant tested species (as for cadmium) or its sensitivity was only 1.6 times lower than the highest sensitivity determined (as for copper), which should be covered by safety factors applied during risk assessments. Therefore, the results for the sediment type and the two heavy metals tested during the present study in combination with the existence of standardized testing protocols, their ease of culture, and short generation time, suggest H. azteca as suitable crustacean model shredder for assessing the toxicity of sediment-associated metals in Europe. [ABSTRACT FROM AUTHOR]

Abstract The accumulation and redistribution of heavy metals in soil in a water-level fluctuation zone (WLFZ) can create ecological risks to reservoirs and reduce river health. Little is known about how heavy metals are accumulated and redistributed in the WLFZ of reservoirs with a high background value of the heavy metal in soil. The site chosen for this case study is the Nuozhadu mega reservoir in the upper Mekong River Basin, which is held back by a dam with a height exceeding 250 m. Five sampling transects were established around the reservoir. Each transect contained three vertical sampling lines representing three land-use types: forest, farmland, and rubber plantations. Soil samples were collected both in the WLFZ and in the infralittoral reference zone (IRZ), and the concentrations of the heavy metals Zn, Cr, Ni, Cu, Mn, and Fe (%) were measured in these samples. We found that the average concentrations of each of these heavy metals were higher in the WLFZ than in the IRZ. The land-use types, especially the rubber plantations and farmlands, determine the redistribution of the heavy metals in the soil of the WLFZ. The heavy metals Cu, Mn, and Ni increased with increasing elevation within the WLFZ, but the metals Cr and Zn decreased with elevation. The results of analysis of variance indicate that the soil properties had certain differences under different land-use types and inundation durations at various elevations, which partly determined the accumulation and redistribution of heavy metals in the WLFZ. We suggest that long-term monitoring of the concentration of heavy metals is needed for soil and water management in the WLFZ of the Nuozhadu reservoir. Highlights • The concentrations of the heavy metals in the WLFZ were higher than that of IRZ. • The Cu, Mn, and Ni increased with the increasing of elevation in the WLFZ. • The Cr and Zn decreased with the increasing of elevation in the WLFZ. • Land use before dam construction has determined the redistribution of heavy metals. [ABSTRACT FROM AUTHOR]

Abstract This study examines the variation in the concentration of eight heavy metals (Cu, Ni, Pb, Cd, Cr, Co, V, Sc) bound on suspended sediments during flow events and those deposited in channel banks. The study was undertaken in Wadi Sekher, an ephemeral flash-flood channel draining the Neot Hovav industrial chemical complex in the semi-arid northern Negev, Israel, at sites varying with bank height and distance from the industrial complex. Metal concentrations were found to be higher in the initial flow and recession than during peak flow. Bound metal concentrations were mainly affected by suspended sediment composition and concentrations. During peak flow the suspended sediment concentration rises and quartz sand is a major constituent. This leads to a decrease in bound metal concentrations, as the larger particles have a weaker affinity to binding. In six sediment samples, taken during the first 15 min of two floods, the bound metal concentrations changed similarly. These changes are suggested to represent variations in the source and cannot be attributed to dilution or binding effects. Six banks were sampled along Wadi Sekher, from the Neot Hovav hydrometric reach downstream to the confluence of Wadi Sekher and Wadi Beer-Sheva, at specified heights, following a bank-full flood. In every cross-section, a significant difference (p < 0.01) was seen in Cu, Cd, Co, V and Sc concentrations with bank height, with highest concentrations at bank-bed intersection. Downstream variations in bound metal concentrations along Wadi Sekher were statistically (p > 0.05) undifferentiated, indicating that the industrial area is not a source point for these metals, and that a constant input exists into the channel from tributaries along the channel. Due to the difficulty in sampling flash floods in ephemeral channels, existing data are not abundant, and our understanding of these environments is therefore limited. This study improves knowledge of interrelated variations in bound metal concentrations in fluvial deposits, in suspended sediment and in water during flash floods. Highlights • Monitored flood events and channel banks in an ephemeral, semi-arid area channel • Bound metal concentrations in suspended sediments and banks during flood events • Bound metal concentrations are highest during initial flow and recessions. • High suspended sediment concentrations at peak flow "dilute" metal concentrations • Highest bound metal concentrations occur at the bottom of channel banks. [ABSTRACT FROM AUTHOR]

The study was performed to determine the bioavailable amounts of cadmium, lead, and zinc in the soils contaminated over the years of Zn-Pb ore mining and processing near Olkusz, Poland, and to identify the environmental risk (RAC) associated with the occurrence of the most mobile forms of these metals in the soil. The authors analyzed the topsoil samples for the basic physical and chemical parameters, as well as for total metal content (by aqua regia extraction), and for percentage of 1 M HCl- and 1 M NH4NO3 - extractable fractions. The results were compared with the content of these metals in a common grass species, Agrostis capillaris. In the study region, the Cd, Pb, and Zn contents were (respectively, in mg∙kg-1): 0.5-33.5, 2-529, and 4-7877. This means that in more than 24%, 30%, and 38% of samples, respectively, the metal content exceeded the limits defined by the Polish Environment Minister's Regulation of September 9, 2002, with nearly 24% of soil samples contaminated by all three metals. On the basis of the Environment Minister's Regulation of September 1, 2016, which is currently in force, and using the allowed limits for subgroup IV (industrial land), set at 15 mg∙kg-1 for Cd, 600 mg∙kg-1 for Pb, and 2000 mg∙kg-1 for Zn, the analysis also found the excessive metal content in a considerable percentage of the topsoil samples (33%, 13%, and 38%, respectively). The content of the studied elements in a common grass species, Agrostis capillaris, was significantly higher than the so-called natural content. A strict association was found between the total Cd, Pb, and Zn content, and the potentially available 1 M HCl - extractable fraction. The environmental risk presented by the content of mobile Cd, Pb, and Zn forms, assessed in all the studied soil samples using Risk Assessment Codes (RAC), demonstrates very high environmental risk associated with Cd, high environmental risk connected with Zn, and moderate environmental risk related to Pb. [ABSTRACT FROM AUTHOR]

To investigate the impact of intensive mining on pollution of heavy metals in aqueous environment, water samples and seven sediment profiles adjacent to REE mine, iron mine, and V-Ti magnetite mine at Anning River, southwest China were collected and analyzed. Our study reveals that: (1) no significant pollution in water near mining regions of Maoniuping REE and Lugu iron mines were observed,(2) most outliers of As, Cd, Ni, Pb, Zn, and Cu in water are distributed at sites near towns not mining regions, except Cr that has been detected only in downstream waters near the V-Ti magnetite mine, because Cr was enriched in V-Ti magnetite mine and existed as oxyanions in water so that CrO42- can be preserved longer than heavy metals existing as cations in alkaline water,(3) although these trace elements in sediment profiles indicated significantly decreased recently, most heavy metals in sediment of Anning River were considerably higher than local background values,(4) source identification of heavy metals in sediment near mining regions is complicated, because the natural contribution from undeveloped ore can also increase content of heavy metals in sediment which cannot be directly assigned as anthropogenic activities. [ABSTRACT FROM AUTHOR]

This study considered the possibility of using visible and near infrared (VNIR) spectral absorption feature parameters (SAFPs) in predicting the concentration and mapping the distribution of heavy metals in sediments of the Takab area. In total, 60 sediment samples were collected along main streams draining from the mining districts and tailing sites, in order to measure the concentration of As, Co, V, Cu, Cr, Ni, Hg, Ti, Pb and Zn and the reflectance spectra (350–2500 nm). The quantitative relationship between SAFPs (Depth500nm, R610/500nm, R1344/778nm, Area500nm, Depth2200nm, Area2200nm, Asym2200nm) and geochemical data were assessed using stepwise multiple linear regression (SMLR) and enter multiple linear regression (EMLR) methods. The results showed a strong negative correlation between Ni and Cr with Area2200nm, a significant positive correlation between As and Asym2200nm, Ni and Co with Depth2200nm, as well as Co, V and total values with Depth500nm. The EMLR method eventuated in a significant prediction result for Ni, Cr, Co and As concentrations based on spectral parameters, whereas the prediction for Zn, V and total value was relatively weak. The spatial distribution pattern of geochemical data showed that mining activities, along with the natural weathering of base metal occurrences and rock units, has caused high concentrations of heavy metals in sediments of the Sarough River tributaries. [ABSTRACT FROM AUTHOR]

The aim of the present study was to determine the level of contamination of the bottom sediments in the Rzeszow reservoir by the selected heavy metals Pb, Cd and Zn, and to identify the potential environmental risks of heavy metals content basing on available assessments and classification of bottom sediments. The Rzeszow reservoir is situated on the Wisłok River in the Podkarpackie Voivodeship, southeaster Poland, was constructed on 1974. Nowadays, as a result of silting, the reservoir reduced its surface and depth, which does not have a positive effect on the assumed functions it is to perform. The study was conducted in 2016. The samples of sediment were collected in five locations. Samples were taken twice: in June and in October. The following concentrations have been determined: cadmium - 0.01 ÷ 0.92 mg•kg-1, zinc - 54.39 ÷ 128 mg•kg-1, lead - 2.98 ÷ 25.42 mg•kg-1. The decline trend in the sediment is following: Zn > Pb > Cd. For the assessment of sediment contamination, following methods: aquatic sediment quality classification used by the Polish Geological Institute - I class, Regulation of the Minister of Environment of April 16 2002 on the types and concentrations of substances contaminating the excavated material - unpolluted and LAW sediment classification - Pb - I/I-II, Cd - I/I-II/II and Zn - I/I-II. The obtained results were compared with the results obtained by the other authors in earlier years, which led to the estimated changes in the concentration of the tested metals. [ABSTRACT FROM AUTHOR]

Sediment acts as both important sink and source for contaminants in aquatic systems. In the present study, the multivariable cokriging method and multiple statistical techniques, including group analysis (GA), factor analysis of mixed data (FAMD), correlation matrices (CMs), and enrichment factor (EF) were used to identify spatial distribution and sources of potentially toxic elements (PTEs) Cr, Cu, Cd, Pb, and Zn in surficial sediments of Dongting Lake in China. The results showed significant spatial heterogeneity in these PTEs in Dongting Lake. The average concentrations of Cr, Cu, Cd, Pb, and Zn were 131.5 ± 45.4, 49.7 ± 17.4, 2.2 ± 1.8, 59.2 ± 18.6, and 152.9 ± 48.0 mg/kg, respectively. The potential ecological risks posed by the trace elements (Cr, Cu, Cd, Pb, and Zn) were evaluated based on the multivariable cokriging predictions, and the results indicated that the ecological risks were high in Southern and Western Dongting Lakes. Multiple analyses showed that Cr, Cu and Zn primarily originated from industrial and domestic sewage wastewater, while Cd and Pb were primarily from agricultural and industrial sources. [ABSTRACT FROM AUTHOR]

This study was made to determine the pollution status and potential ecological risk of heavy metals in sediment of Persian Gulf. Surface sediments were collected seasonally by Peterson grab, and the concentrations of heavy metals were measured by using inductively coupled plasma-optical emission spectrometry (ICP-OES). The range concentrations obtained in mg/kg were 10,800-22,400 for Fe, 5.32-10.12 for Pb, 24.63-42.38 for Ni, 22.52-39.46 for Cu, and 31.64-47.20 for Cr. The concentrations of Pb, Ni, Cu, and Cr have been found lower than the Interim Sediment Quality Guidelines and probable effect level values suggesting that heavy metal contents in sediments from area of study would not be expected to cause adverse biological effects on the biota. The obtained enrichment factor values for various metals were between minimal enrichment (Pb = 0.5) and extremely enrichment (Cu = 3.11). The values of Igeo for Pb, Ni, Cu, and Cr were characterized under no pollution (0). The highest value of potential ecological risk index (RI) (8.36) was observed at St. 4 while the lowest value (5.25) was detected at station 6. Based on potential ecological RI, the Persian Gulf had low ecological risk. [ABSTRACT FROM AUTHOR]

This study was performed to determine the distribution and chemical fractions of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in sediment from three sampling areas in Swan Lagoon, and their relation to the physiochemical properties of sediment were explored. The results revealed that Cd in sediment from the sand part (SP), muddy sand part (MSP) and sand muddy part (SMP) were potentially highly susceptible and bioavailable since the exchangeable fractions were 21.0%, 27.4%, and 32.1%, respectively, of the total concentrations. A portion of Pb and Zn were observed as reducible fractions owing to their affinity to Fe-Mn; they were able to complex with Fe-Mn oxides and oxyhydroxides in the sediment. A large amount of Cu in the oxidizable fraction may be due to the fact that Cu can easily form stable complexes with organic matter. Cr was overwhelmingly found in the residual fraction, suggesting that Cr was strongly bound in mineral lattices. Enrichment factors (EF) indicated that Cd in three sampling areas suffered severe enrichment, whereas other metals were present in only minor amounts. In addition, Cd may pose a medium to high risk in the MSP and SMP based on risk assessment codes. According to the mean probable effects level quotient, the samples from the MSP and SMP had a 21% probability of toxicity. The multivariate statistical analysis suggested that sediment texture (d0.5, sand and silt), Fe-Mn, and the total organic carbon (TOC) influenced the distribution of the studied metals and their chemical fractions. [ABSTRACT FROM AUTHOR]

Background and Objective: The establishment of pelletizing and steel industries in Ardakan suburbs has increased the pollutants such as heavy metals into the environment. The purpose of this study was to investigate the contamination of the area soil by heavy elements around these industries using the pollution index (PI), comprehensive pollution index (NIPI), accumulation index (Igeo) and enrichment index (EF). Materials and Methods: 57 soil samples were prepared by systematic-random sampling from 0 to 5 cm depth and levels of As, Cd, Cr, Mo, Ni, Pb, V and Zn were analyzed by ICP-OES. Results: The highest and lowest mean of Igeo (0.49 and 0.36) and PI (2.16 and 1.17), were related to nickel, and the highest EF was calculated for Zn at about 25.1 and the lowest were detected for molybdenum approximately that was 17.1. The EF index of lead, vanadium and zinc, which was 15.8%, 5.3% and 1.8%, respectively, classified the study area in a medium enrichment class. Hot spots of lead, vanadium, nickel and zinc was at the nearest distance to these industries and downstream of wind direction. Conclusion: Indicators of Igeo and EF showed a low level of soil pollution. The PI and NIPI indices in most stations were classified in medium pollution class, and the highest of these indicators was related to the surface soil of station 30, which was located near the steel industry. Therefore, it can be concluded that the activities of these industries had affected the soil contamination of the study area. [ABSTRACT FROM AUTHOR]

Background and Objective: Marine sediments are the most important component of monitoring the health of aquatic ecosystems. The present study uses sediment quality indices to determine the contamination status in Qeshm ecosystems and to evaluate the toxicity of the elements studied for its organisms. Materials and Methods: Sampling of surface sediments of seven stations was carried out on Qeshm coastal areas. The samples were digested by a combination of nitric acid and perchloric acid, and the concentration of metals was measured by atomic absorption spectrometry. Results: The results of modified Hazard Quotient indicated a high pollution rate for copper and nickel metals in most stations, which was consistent with the results of the Potential Contamination Index in relation to nickel metal. Additionally, the results of the Potential Contamination Index and Contamination Factor agreed with the amount of lead element. According to the results, the pollution index of Hamoon Lake and Zakeri pier was highly contaminated and Modified Pollution Index demonstrated a contamination in Romacha, Hamoon Lake, Zakeri pier and Nazes areas. The enrichment factor associated with contamination regarding most of the heavy metals confirmed the indices used to evaluate the comtamination in the study area. Conclusion: Due to the higher concentrations of the heavy metals in the sediments than that of the quality guidelines, the high toxicity of sediments for the aquatic ecosystems was confirmed. The Romachah, Hamoon, Zakeri stations showed higher pollution levels and sever toxicity for aquatic life. Copper, nickel and in some cases lead, were the main heavy metals that contaminated the sediments in the region. [ABSTRACT FROM AUTHOR]

Background and Objective: Heavy metals contaminations are readily bioaccumulated in aquatic systems and lead to increased concentrations in food chains, posing a serious threat to human health, water-related organisms and aquatic ecosystems. The purpose of the present study was to determine the concentration of heavy metals in surface sediments of CheshmehKile River, to evaluate environmental and ecological risk and to determine the degree of contamination of the elements studied. Materials and Methods: In this study, 25 samples of surface sediment were collected from the CheshmehKile River. The heavy metals content of the samples was measured by inductively coupled plasma-optical emission spectrometry. According to the content of heavy metals in sediment samples, environmental and ecological risk indices were calculated. Also, river contamination was evaluated by comparing the elements studied values with the sediment quality guidelines values. Results: The mean concentration of chromium, manganese, iron, cobalt, nickel, zinc and arsenic were 41.27, 356.35, 16756.32, 9.17, 11.87, 41.24 and 24.60 µg/g, respectively. Based on the values of the CF and Igeo indices, all of the elements, with the exception of arsenic, showed a low degree of contamination. The indices of Eir and RI also showed the lowest ecological risk at all stations. Conclusion: The results of this study showed that the surface sediments of CheshmeKile River in Mazandaran province were somewhat contaminated with arsenic. However, fortunately, the river sediments were of good quality from the point of view of the content of chromium, manganese, iron, cobalt, nickel and zinc. [ABSTRACT FROM AUTHOR]

Chemical activation and microwave assisted activation were adopted to modify biochar. Activated biochars were characterized by SEM, BET, FTIR, XRD and XPS. Raw biochar, activated biochars and commercial activated carbon were compared as remediation strategies for sediment from the Xiangjiang River containing 14.70 mg/kg Cd. After the treatment by activated biochar, the overlying water and pore water concentration of Cd decreased by 71% and 49%, respectively. And the threat of heavy metal along with bioavailability of Cd was depressed. Moreover, the immobilsation of Cd in sediment was related to BET surface area and the content of oxygen containing functional groups of activated biochars. Furthermore, a PCR-DGGE-based experiment was performed for the detection of microbial community. The indigenous microbial community was affected and new microbial community appeared after treat by activated biochar. Activated biochar can be used as an inexpensive and efficient in situ remediation material of sediment containing metal. [ABSTRACT FROM AUTHOR]

Several tools have been developed and applied to evaluate the metal pollution status of sediments and predict their potential ecological risk assessment. To date, a comprehensive relationship between the information given by these sediment tools for predicting metal bioavailability and the effective toxicity observed is lacking. In this work, the possible inter-correlations between the data outcoming from using several qualitative evaluation tools of the sediment contamination (contamination factor, CF, the enrichment factor, EF, or the geoaccumulation index, Igeo), metal speciation on sediments (evaluated by the modified BCR sequential extraction procedure) and free metal concentrations in pore waters were studied. It was also our aim to evaluate if these assessment tools could be used for predicting the pore waters toxicity data as toxicity proxy. Principal component analysis and cluster analysis revealed that two quality indices used (CF and EF) were highly correlatable with the more labile fractions from BCR sediment speciation. However, neither of these parameters did correlate with the toxicity of pore waters measured by the chronic toxicity (72 h) in Pseudokirchneriella subcapitata . In contrast, the toxic effects of the given total metal load in sediments were better evaluated by using an additive metal approach using pore water free metal concentrations. [ABSTRACT FROM AUTHOR]

Useful wild plants usually decrease the content of biologically active substances in culture. However, there are no studies on the reverse process and no evidence whether the level of biologically active compounds increases in plants escaping from culture and becoming invaded in natural communities (invasive species). We studied Aronia melanocarpa, A. arbutifolia, A. × prunifolia, 2 samples of cultivated A. mitschurinii in the arboretum of the Main Botanical Garden (Moscow, Russia) and one sample of invasive A. mitschurinii from the Moscow region. The task of the study was to determine the degree of heritability of macro- and micromorphological characters of North American plants introduced to Europe. The identification of the samples most promising for further broad cultivation by their antioxidant activity and the content of microelements in leaves was also our research purpose. The diagnostic features of the introduced North American Aronia were found to be inherited under culture conditions. The mass of fruits increases in this order: A. arbutifolia → naturalised A. mitschurinii → A. × prunifolia → A. melanocarpa → cultivated A. mitschurinii. An original table was compiled to compare the studied taxa on 21 biomorphological features. Naturalising plants have a higher antioxidant activity of alcohol extracts than cultivated plants, and, on the contrary, lower antioxidant activity of water extracts. The leaves of A. mitschurinii have the highest content of 10 microelements: Fe, Mn, Sr, Zn, Se, Cu, Mo, Cr, As and Sb; A. × prunifolia has the highest content of 6 microelements: Ni, Co, V, Cd, Pb, and Sn; and A. arbutifolia has the highest content of B. Our observations suggest that naturalising plants of Aronia have a potential source of useful bioactive compounds. [ABSTRACT FROM AUTHOR]

Information about the behavior and temporal evolution of heavy metals in agricultural soils is limited, particularly about greenhouse soils on semiarid lands, indeed it nonexistent. Western Almería (Southern Spain) is a semiarid land where some 30,000 ha are occupied by greenhouses with high productivity. As these greenhouses are fundamental to the socioeconomic development of this area, they should be maintained and well conserved. However, there are indications that long‐term intensive agriculture with considerable agrochemicals use can deteriorate soil quality, which in turn, would reduce productivity and food quality. This study was conducted to investigate soil contamination and the temporal trends of heavy metal concentrations in greenhouse soils of western Almería. Contamination level, availability, and sources of metals were evaluated by the extractable fraction percentage, by indices zinc equivalent, geoaccumulation, enrichment factor and pollution load, and by a correlation analysis between soil properties and metal contents. The results showed that the total contents of Cd, Cu, Ni, and Pb, and the available concentration of Cd, Cu, Pb, and Zn, were significantly higher than background levels. Temporal patterns indicated that these elements accumulate in greenhouse soils. After more than 20 years of intensive agriculture, the available concentration of elements, and contamination, had clearly increased. [ABSTRACT FROM AUTHOR]

Environmental monitoring of the levels of potentially toxic metals is of importance because of possible adverse effects on living species. This study was conducted to assess the levels of Cd, Cr, Cu, Hg, Mn, Pb, U and V in water, sediment and peat samples collected from the region of Wonderfonteinspruit. Water samples were simply filtered and acidified with HNO3 prior to analysis. Sediment and peat were oven-dried, ground, sieved and mineralised using a microwave digestion system. Concentrations of the selected elements in all samples were determined by inductively coupled plasma-mass spectrometry. A Zeeman mercury analyser was also used for quantification of Hg in the same sediment and peat samples. The method validation was carried out using SRM 1643e water and BCR 320R sediment certified reference materials. The results showed no significant difference at 95% level of confidence between the certified and measured values after using the Student's t-test. The levels of Cd, Cr, Cu, Pb, V and U found in rivers and dams were lower than the tentative South African water quality range guideline for domestic and irrigation purposes. However, water from dams and certain rivers was unsuitable for irrigation and domestic use. [ABSTRACT FROM AUTHOR]

Surface water and sediment samples were collected from Ajay River basin to appraise the behavior of heavy metals with surrounding environments and their inter-elemental relationships. Parameters like pH and organic carbon are having a minimal role in heavy metal distribution while some elements like Fe and Cu showed great affinity for organic matter based on linear regression analysis (LRA). Ficklin diagram justified that river basin is not contaminated through acidic pollutants. The river basin is highly enriched with Cu, Cd, Pb, and Ni which were much higher than world average values, average shale standard, effect range low (ERL), and threshold effect level (TEL). PCA and LRA verified that Cu, Cd, Pb, and Ni were mainly derived from anthropogenic inputs, and others like Fe, Mn, Zn, and Co came from geogenic sources. Pollution indices revealed that river basin is moderately to highly contaminated by Cu, Cd, and Ni. Furthermore, Ajay River basin is under strong potential ecological risk based on the obtained value of risk index and probable effect level/effect range median quotient index. However, river basin is strongly influenced by lithological properties, diversified hydrogeological settings, mineralization and mobilization of subsurface materials, and urban and industrial effluents which are controlling the heavy metals. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Water & Land Development is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rivers may receive pharmaceuticals, personal care products, and environment estrogens, which are emerging concerns, from various sources. Understanding the fate of these emerging contaminants (ECs) from the sources to their receiving river is important for assessing their ecosystem risk. Here, the occurrence, seasonal variation, spatial distribution, and ecological risk of 22 ECs in water and sediments from the Jilin Songhua River, as well as in the effluents from the riverside Jilin wastewater treatment plant (WWTP) were investigated. Results indicated that estriol with the highest median concentration of 21.5 ng L−1 in the river water and with the highest median concentration of 481.5 ng g−1 in the sediments, and methylparaben with the highest concentration of 29.6 ± 2.9 ng L−1 in the WWTP effluents were the predominant contaminants. The total concentration of ECs in the river water in the dry season was about 1.5 times higher than that in the wet season. The concentrations of these ECs close to the contaminated tributary and the WWTP were relatively high. Risk assessment showed that the maximum risk quotient value of estrone was 1.07 in the river water and estriol was 2.10 in the effluents. In addition, erythromycin posed generally medium risk in the river water and WWTP effluents. It should be paid attention to the prior control of the three contaminants in the river region. [ABSTRACT FROM AUTHOR]

This study reports number, size and color distribution, and metal contents of microplastics as well as adherent sediments along the Persian Gulf. Samples were collected from 9 stations in summer 2015 with a sampling time interval of 10 days. Plastic size of 2–5 mm, and ≤0.25 mm with 45 and 33% and white and colorless plastics with 62 and 33% had the highest abundance considering number per m 2 , respectively. In general, the majority of collected plastics (79%) were smaller than 5 mm (defined size for microplastics). The mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of plastic fragments were 115, 531, 32.2, 0.035, 0.915, 2.03, 4.59, and 3.6 μg g −1 , respectively while the mean Al, Fe, Mn, Cd, Cr, Ni, Pb, Cu contents of sediments were 186, 3050, 127, 0.81, 5.01, 14.5, 48.6 and 5.43 μg g −1 respectively. There were significant differences between the abundance of plastic items as well as the all examined metal concentrations of microplastics and sediments at different sampling times. As there is no regular cleanup program in the studied areas, significant differences between plastic items number at different sampling times (with higher plastic items number at the first day of sampling) showed that a large number of plastic items may enter from beaches to the sea and become available to marine organisms. [ABSTRACT FROM AUTHOR]

The existence of Organochlorine pesticides (OCP's) and trace metals in tropical aquatic environments may cause a severe threat on account of their ubiquitous nature and long persistence. Monitoring of such contaminants has assumed immense significance in recent times. The present study assessed the OCP's and trace metal contamination in the surface sediments of the Vembanad wetland system in India. Various pollution indices were calculated to determine the sediment quality of the system and were also compared with uncontaminated sediments. Geo-accumulation index for Mercury varied from moderately to extremely polluted. The mean concentration of pesticide residues and trace metals in the sediments of Vembanad is found to be higher than in other aquatic systems in India. The situation demands further studies which focus on the potential bioaccumulation of OCPs and metals in the benthic food chain, succeeding biota and their impact on human consumption as the system supports a huge population for their livelihood. The Present study provides a baseline information on the spatial distribution of priority pollutants along with ecological risk status of Vembanad estuarine system (VES). [ABSTRACT FROM AUTHOR]

A Characterization and assessment study was conducted for trace metals pollution in surface sediments at six sites including harbors, bays and river input along Lebanese coast (LCZ). A particular attention was given to Tripoli Port in order to identify the main sources of trace metals pollution inside this harbor. Total metals concentrations were compared with those reported for the shale. The results revealed that trace metals (Cd, Pb, Zn, and Cr) contamination was significantly localized at Beirut Port, which is classified as the most highly polluted site. At Tripoli Port site, metals contamination was classified as moderate; it is affected by shipping, ship maintenance activities and sewage outfall. According to the SQGs guideline, the biological adverse effect of Cd, Pb and Zn were expected to occur frequently at Beirut Port. The results obtained would be helpful in developing more effective harbor management strategies to control and monitor the metal discharges. [ABSTRACT FROM AUTHOR]

This study's objectives were to evaluate the elements degree of contamination in the Tajan River and the status of contamination in this river for future ecotoxicology studies. Based on geo-accumulation index (I geo ) and contamination factor (CF) indices, Cr, Mn, Fe, Ci, Ni and Zn showed low contamination levels at all stations, while Se showed a very high degree of contamination. Potential ecological risk factor (E r i ) and risk index (RI) indices values showed low ecological risk for the river, and this was confirmed by the pollution load index (PLI) results as well as a comparison of the concentrations of these elements with the mean values of the earth's crust and sediments worldwide. Overall, the results showed that the river cannot be regarded as a contaminated river with respect to the elements studied (with the exception of selenium and arsenic) for ecotoxicology studies, but can be considered a reference river. [ABSTRACT FROM AUTHOR]

Thirty bottom sediment samples were collected from northern Hurghada coast, Red Sea, Egypt to evaluate the level of anthropogenic pollutants, using enrichment factor (EF), potential ecological risk index (PERI), soil pollution index (SPI), potential contamination index (Cp) and multivariate statistical analysis (correlation analysis, principal component analysis, and hierarchical cluster analysis). Fe, Mn, Zn, Pb, Ni, Cu, Co and Cd were analyzed by Atomic Absorption Spectrophotometer. Results indicated that the average values of Pb and Cd were greater than the ones recorded from many other worldwide coastal areas. The studied sediments are extremely severe enrichment with Pb and Cd (EF > 50), severe enrichment with Zn (EF = 10–25), very high risk with Cd (PERI ≥ 320), high risk with Pb (160 ≤ PERI ˂ 320), highly contaminated with Pb (SPI > 3), a severe contamination with Pb (Cp > 3). The accumulation of pollutants is associated with the muddy and fine sediment; especially the studied area is a semi-closed bay, characterized by long time of water retention. Possible sources of metals pollution in the studied area are shipment operations and anticorrosive and antifouling paints, dredging and land filling, municipal wastewater from tourist centers and fishermen cargo boats. [ABSTRACT FROM AUTHOR]

Impact of pH variation of overlying water column on transport and transformation of Cu-sediment complexes in the bottom mangrove sediments was investigated by using different metal extraction studies. The total Cu concentration in the studied sediments varied from ~64 ± 1 to 78 ± 2 mg·kg −1 . The sequential extraction study showed that a major part of the sedimentary Cu (85–90% of the total sedimentary Cu) was present within the structure of the sediments with minimum mobility and bioavailability. The redistribution of non-residual Cu among the different binding phases of the sediments was observed at different pH. It was found that Cu shifted from the different non-residual binding phases to the organic binding phase of the sediments at higher pH. Partial leaching of sedimentary Cu-SOM complexes (with increasing stability as determined by kinetic extraction study) was observed at higher pH. This study infers that increase in pH of overlying water column may release Cu-SOM complexes and increase the mobility of Cu-complexes in mangrove systems. [ABSTRACT FROM AUTHOR]

Almost nothing is known about the activities and diversities of microbial communities involved in As methylation in arsenic-rich shallow and deep sediments; the correlations between As biomethylation and environmental parameters also remain to be elucidated. To address these issues, we collected 9 arsenic-rich soil/sediment samples from the depths of 1, 30, 65, 95, 114, 135, 175, 200, and 223 m in Jianghan Plain, China. We used microcosm assays to determine the As-methylating activities of the microbial communities in the samples. To exclude false negative results, we amended the microcosms with 0.2 mM As(III) and 20.0 mM lactate. The results indicated that the microbial communities in all of the samples significantly catalyzed arsenic methylation. The arsM genes were detectable from all the samples with the exception of 175 m, and 90 different arsM genes were identified. All of these genes code for new or new-type ArsM proteins, suggesting that new As-methylating microorganisms are widely distributed in the samples from shallow to deep sediments. To determine whether microbial biomethylation of As occurs in the sediments under natural geochemical conditions, we conducted microcosm assays without exogenous As and carbons. After 80.0 days of incubation, approximately 4.5–15.5 μg/L DMAsV were detected in all of the microcosms with the exception of that from 30 m, and 2.0–9.0 μg/L MMAsV were detected in the microcosms of 65, 114, 135, 175, 200, and 223 m; moreover, approximately 18.7–151.5 μg/L soluble As(V) were detected from the nine sediment samples. This suggests that approximately 5.3, 0, 8.1, 28.9, 18.0, 8.7, 13.8, 10.2, and 14.9% of total dissolved As were methylated by the microbial communities in the sediment samples from 1, 30, 65, 95, 114, 135, 175, 200, and 223 m, respectively. The concentrations of biogenic DMAsV show significant positive correlations with the depths of sediments, and negative correlations with the environmental NH4+ and NaCl concentrations, but show no significant correlations with other environmental parameters, such as NO3-, SO42+, TOC, TON, Fe, Sb, Cu, K, Ca, Mg, Mn, and Al. This work helps to better understand the biogeochemical cycles of arsenic in arsenic-rich shallow and deep sediments. [ABSTRACT FROM AUTHOR]

In recent years, the treatment of wastewater treatment plant (WWTP) effluent has gained increasing attention. However, researches on the relationships between nitrogen forms and nitrogen removal efficiency are very limited. Based on the fact that the nitrogen forms in the WWTP effluent may vary as the season changes, the nitrogen removal efficiencies of an integrated ecological floating bed (IEFB) was studied under different influent nitrogen forms. In addition, the effects of sediments in the system were also quantified during the experiment. Results showed that the total nitrogen (TN) removal rates of the IEFB were 25.61 ± 5.72% and 60.03 ± 7.00%, respectively, when the main influent nitrogen forms are nitrate and ammonia. The sediments in the system also played vital roles in the removal processes: when the sediments were covered with a polyethylene membrane, the total nitrogen (TN) removal rate of the system dropped from 27.86 ± 5.53% to 14.78 ± 4.97%, and the total phosphorus (TP), from 58.77 ± 6.20% to 33.51 ± 25.52%. [ABSTRACT FROM AUTHOR]

Huang, H.; Cai, L.; Luo, Y.; Wang, J.; Liu, Y.; Sun, X.; Lin, H., and Wang, W., 2018. Distribution and potential ecological risk assessment of heavy metals in surface sediments of Xiamen Bay. In: Wang, D. and Guido-Aldana, P.A. (eds.), Select Proceedings from the 3rd International Conference on Water Resource and Environment (WRE2017). Journal of Coastal Research, Special Issue No. 84, pp. 125–133. Coconut Creek (Florida), ISSN 0749-0208. The present work envisages the potential ecological risk assessment of heavy metals in surface sediments of Xiamen Bay. Based on the survey of the surface sediments in May 2012, the concentrations of heavy metals Cu, Pb, Zn, Cd, Cr, Hg and As in sediments were 1.2~57.2, 6.7~76.6, 13.3~150.0, 0.035~0.531, 1.48~92.7, 0.018~0.164, 1.9~10.9 mg.kg−1, respectively. Significant positive correlations were observed amongst the concentrations of Cu, Zn, Hg and As and Total Organic Carbon (TOC). PCA analysis data showed the first three main factors shared 72.70% of the total variance. All stations in the studied area recorded Eir < 40 for Cu, Pb, Zn, Cr and As, which were low risk, while Cd reported the highest ecological risk. The results of refractive index (RI) showed that 40.9% of stations in the Xiamen Bay were at a low risk, 45.5% of them were at a moderate risk, while 13.6% were at high ecological risk. [ABSTRACT FROM AUTHOR]

Algal growth causes a drastic change in aquatic conditions over a diel cycle, which may induce sensitive feedback systems in sediments, causing P release. In this study, a microcosm experiment was performed using a suction sampler (Rhizon) to observe changes in soluble reactive phosphorus (SRP) and soluble Fe(II) concentrations in the top 20 mm sediment layer on a 3-h time interval, at different phases of harmful algal bloom (HAB) development. The results showed that the algal blooms prevailed up to 15 days after incubation, after which the process of bloom collapse proceeded until the 70th day. The concentrations of pore-water soluble Fe(II) and SRP increased throughout the incubation period. Compared to day 1, maximum increases of 214% in soluble Fe(II) and 387% in SRP were observed at night during the bloom and collapse periods, respectively. The diffusive fluxes of Fe and P at the sediment-water interface (SWI) generally corresponded to their changes in concentrations. Hourly fluctuation in soluble Fe(II) and SRP concentrations were observed with two distinct concentration peaks occurred at 21:00 p.m. and 06:00 a.m. (or 03:00 a.m.), respectively. These findings suggest that Fe-P coupling mechanisms are responsible for the release of P from sediments. During the collapse period, soluble Fe(II) concentrations were suppressed by the increase of labile S(-II) at night. Meanwhile, SRP concentrations were decoupled from Fe cycling with small fluctuations (<11% RSD) on an hourly timescale, and the decomposition of algae was a dominant source contributing to the release of P from sediments. These results significantly improved the understanding of processes and mechanisms behind the stimulated release of P from sediments during HABs. [ABSTRACT FROM AUTHOR]

A geochemical study of the trace metals and lead isotopic ratios of soil and sediments in Korba, Chhattisgarh, India is presented here for the first time. Korba, the nation's ‘power hub’ is also the fifth among its eighty-eight most critically polluted industrial hotspots. A very high mean concentration (in mg kg-1) of V (308), Cr (567), Mn (3442), Co (92), Cu (218), Zn (426), Pb (311), Th (123) and U (32) characterized the sediments of the studied area with mean I geo values of the trace metals ranging from −2.29 to 3.27. In the two-ratio scatter Pb isotope plot of the different environmental matrices, except for human blood, coal, soil, sediments, non-washed leaves, flyash and diesel overlapped linearly in the mixing line between diesel as the highest anthropogenic end member and a core sediment fraction representing its geogenic counterpart. The mean 207 Pb/ 206 Pb Pb ratio decreased in the order of diesel (0.9012) > flyash (0.8757) > coal (0.8498) soils and sediments (0.8374) > lowest core sediment fraction (0.8017). Principal Component Analysis (PCA) of the trace metal data extracted V, Cr, Cu, Zn, Pb, U and Th in the first component PC1. The northeastern part of the study area revealed major hotspots of V, Cu, Co, Zn and Pb near the flyash dykes of the power stations. Human blood used as a biomarker for Pb pollution in this study had a mean blood lead level of 28 μg/dl with a distinctive high 207 Pb/ 206 Pb ratio of 0.8828. [ABSTRACT FROM AUTHOR]

Investigating competitive adsorption on river/lake sediments is valuable for understanding the fate and transport of heavy metals. Most studies have studied the adsorption isotherms of competitive heavy metals, which mainly comparing the adsorption information on the same concentration. However, intrinsically, the concentration of each heavy metal on competitive adsorption sites is different, while the adsorption energy is identical. Thus, this paper introduced the site energy distribution theory to increase insight into the competitive adsorption of heavy metals (Cu, Cd and Zn). The site energy distributions of each metal with and without other coexisting heavy metals were obtained. It illustrated that site energy distributions provide much more information than adsorption isotherms through screening of the full energy range. The results showed the superior heavy metal in each site energy area and the influence of competitive metals on the site energy distribution of target heavy metal. Site energy distributions can further help in determining the competitive sites and ratios of coexisting metals. In particular, in the high-energy area, which has great environmental significance, the ratios of heavy metals in the competitive adsorption sites obtained for various competitive systems were as follows: slightly more than 3:1 (Cu-Cd), slightly less than 3:1 (Cu-Zn), slightly more than 1:1 (Cd-Zn), and nearly 7:2:2 (Cu-Cd-Zn). The results from this study are helpful to deeply understand competitive adsorption of heavy metals (Cu, Cd, Zn) on sediment. Therefore, this study was effective in presenting a general pattern for future reference in competitive adsorption studies on sediments. [ABSTRACT FROM AUTHOR]

Sediments from continental shelves are sensitive to changes in both oceanic and terrestrial conditions, and, therefore, magnetic minerals in such sediments are affected strongly by depositional and diagenetic processes. Here, we investigated systematically an N-S transect of three sediment cores from the central South Yellow Sea (SYS) muddy area. Magnetic data indicate the presence of a horizontally distributed thick greigite-bearing layer. From an age model based on published magnetostratigraphy, accelerator mass spectrometry 14C dating ages, sedimentary characteristics and foraminiferal analysis, this layer was deposited within marine isotope stages (MIS) 17-13, following an enhanced sulphidic period over MIS 21-19 when the YS Warm Current and the associated YS Cold Water Mass were strong and where underlying sediments have higher total organic carbon, total sulphur and trace element molybdenum contents. Trace element cadmium enrichment in the greigite-bearing layers is documented for the first time, which indicates that weakly sulphidic (i.e. with trace levels of free H2S) conditions existed before greigite formed in a sulphidic environment during early diagenesis. It also indicates that subsequent conditions free of oxygen and H2S after greigite formation are more favourable for its preservation. We propose that organic matter supply was controlled over an extended period by moderate primary productivity. The combined effects of palaeoclimate and local tectonic subsidence were crucial for the formation and preservation of the identified greigite. In brief, our study improves understanding of the formation and preservation mechanisms of greigite in continental shelf sediments and reveals mid-Pleistocene palaeoenvironmental changes in the SYS. [ABSTRACT FROM AUTHOR]

Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by gas chromatography–mass spectrometry. Twenty samples were collected from the surface sediments of Haizhou Bay in this survey. This research aimed to identify the PAHs' contamination level, composition pattern, pollution sources, and assess the ecological risk of PAHs. The results showed that the sum of PAH concentrations ranged from 116.6 ng g−1to 2414.9 ng g−1(mean: 662.42 ng g−1), which is higher than the reported values for different wetlands worldwide. Three- and four-ring PAHs (accounts for more than 70% of the total PAH content) were predominant in the wetland sediment. The PAHs source distribution in the surface sediments were determined using diagnostic ratio and PCA/MLR. Consequently, multiple PAHs sources were found. Of the total PAH, 79.25% was derived from vehicular emission, 20.75% from coal combustion. The effect range low/effect range median (ERL/ERM) values indicated a low toxicity risk level. However, the fluoranthene concentrations exceeded the ERL level, and even the ERM level, in some stations. The mean effects range–median quotient (M-ERM-Q) suggests a low ecological risk for the PAHs in the sediments. [ABSTRACT FROM AUTHOR]

Levels of heavy metals, i.e., chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), cadmium (Cd), and lead (Pb) in surface sediment of Buriganga River, Bangladesh were investigated to assess ecological risk. The mean concentration of Cr, Ni, Cu, As, Cd, and Pb in sediments was 297, 240, 280, 21, 7.7, and 731 mg/kg, respectively. Certain indices, including the enrichment factor (EF), pollution load index (PLI), and contamination factorwere used to assess the ecological risk. The mean range of PLI was 2.9 to 13 during winter and 2.4 to 11 during summer season, indicating progressive deterioration of sediment due to metal contamination. The sum of toxic units (∑TUs) for all the sampling sites was greater than 4, indicating a moderate to serious toxicity of heavy metals in sediment. However, thevalues of Cd ranging from 6.7 to 61 revealed that the examined sediments were strongly impacted by Cd. Considering the severity of potential ecological risk for single metal, the descending order of contaminants was Cd > Pb > Cu > Ni > As > Cr. In view of the potential ecological risk, sediments of Buriganga River showed considerable to very high potential ecological risk. [ABSTRACT FROM AUTHOR]

Copyright of Environmental Research, Engineering & Management / Aplinkos Tyrimai, Inžinerija ir Vadyba is the property of Institute of Environmental Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Health status of freshwater fish, Cirrhina mrigala was studied by qualitative and quantitative histopathological analysis, alterations in frequency/prevalence percentages (%) and histological alteration indices (HAI) in response to metal contaminated sediments of the River Ravi aquatic ecosystem. Histo-structures of gill and liver samples of fish were analyzed and comparison between the degree of damage of the alterations in fish organs was performed after exposure to metal contaminated sediments for 7, 14 and 28 days under semi-static water renewal bioassays. Histopathological studies revealed marked histological alterations in the gills and liver of exposed fish as compared to normal tissue structure observed in control fish. The frequency and prevalence percentages observed in 28-day exposed fish were significantly higher as compared to 7- and 14-day exposed fish. The order of frequency and prevalence percentage for gills and liver of exposed fish was as: 28-day > 14-day > 7-day. The highest prevalence percentages recorded were 83 and 80% as focal area of necrosis in gill and liver, respectively, after 28-day exposure. The lowest prevalence percentage observed in 7-day exposed Cirrhina mrigala was dilation of sinusoids (17%). [ABSTRACT FROM AUTHOR]

Sediments samples from six seaports of NSW, Australia were analysed for the presence of metal contamination. Geoaccumulation index (Igeo), enrichment factor (EF), pollution load index (PLI), potential ecological risk (PER) and sediment pollution index (SPI) along with multivariate statistical analysis were used to identify the pollution pattern and possible sources of metals in the ports. The results demonstrate Cu, Pb and Zn pollution (Igeo > 5) at most sites and enrichment of As, Ni, Mn (EF > 3) and other metals. The PER recommends serious pollution at Port Kembla and Eden. By contrast, PLI and SPI demonstrate high contamination in all ports with exception of Port Botany and Yamba. PCA and cluster analysis detected major groups of elements in which three distinct clusters of pollutants and sites were apparent by dendrogram which portray simple and effective baseline scenarios for port activity-related quality assessment of surface sediments. [ABSTRACT FROM AUTHOR]

This study investigated the ability of the mangrove species to accumulate heavy metals such as lead (Pb), copper (Cu) and zinc (Zn). Concentrations of these metals in sediment, roots and leaves of Avicennia alba, Sonneratia alba, Avicennia marina and Rhizopora mucronata found in the mangrove ecosystem of the Porong River estuary, Sidoarjo, East Java, Indonesia were measured. The bio-concentration factor (BCF) and translocation factor (TF) were calculated. The results showed that Pb concentrations in the roots and leaves of mangroves were 0.0038-0.0505 mg/kg and 0.0042-0.0395 mg/kg, respectively, while Cu concentration in the roots of mangroves was 0.2658-0.3390 mg/kg and in the mangrove leaves was 0.0655-0.1490 mg/kg. The average concentration of Zn found in mangroves ranged from 1.327-3.1380 mg/kg in the roots and 1.767-3.674 mg/kg in the leaves. Among all the mangroves, the highest BCF values for Pb, Cu and Zn were found in Avicennia alba. However, the highest TF for Pb and Zn was found in Sonneratia alba. On the other hand, the highest TF for Cu was found in Rhizopora mucronata. The capability of Avicennia alba to accumulate Pb, Cu and Zn heavy metals compared with other species is highly important for determining a suitable species for phytoremediation. [ABSTRACT FROM AUTHOR]

During Cruise 62nd of the R/V ' Professor Gagarinsky' in September, 2014, the carbonate system of sediments and contents of nutrients and organic carbon in pore water were studied in two geochemical stations located in hypoxia areas in the Peter the Great Bay. It was established that the concentrations of silica, phosphorus, and ammonium increase by 5, 10, and 20 times, respectively, with sediment depth to 70-80 cm. The alkalinity, dissolved inorganic carbon, and the partial pressure of carbon dioxide significantly increase with depth, while рН value and organic matter (ОM) decrease. Changes in the chemical composition of pore water with sediment depth (0-80 cm) are caused by anaerobic microbial degradation of OM, concentration of which in the top sediment layer is 2-3%. The degradation products of OM in the bottom waters of bay and pore waters of bottom sediments indicate that its main sources are diatoms. During hypoxia, the oxygen demand rate by sediment surface near Furugelm Island is estimated to be 5 mmol/(m day). A combination of such factors as downwelling circulation, the absence of photosynthetically active radiation, and the high oxygen demand rate at the water/sediment interface provides hypoxia formation in the depressions of the Peter the Great Bay bottom topography. [ABSTRACT FROM AUTHOR]