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1.
PurposeThe pollution of marine sediments by heavy metals is still a major concern, especially in zones affected by industry or mariculture. Toxicity of sediment heavy metal contents may be assessed using sequential extraction (SE) procedures, minding inherent constraints of such approaches. In this study, we investigated heavy metal speciation and toxicity in anoxic marine sediments in Zhelin Bay, a mariculture bay in Southern China, using an SE and acid volatile sulfur-simultaneously extracted metals (AVS-SEM) approach. Materials and methodsSpeciation of Cd, Cu, Ni, Pb, and Zn were studied by a modified SE of five fractions, adapted to separate organic and sulfidic metal fractions in anoxic sediments: F1 weak acid soluble (readily available), F2 reducible fraction, F3 organic matter-bound fraction, F4 sulfide-bound fraction, and F5 residually bound fraction. Toxicity predictions based on the sum of non-residual (NR) metal fractions from sequential extraction were compared to predictions based on AVS-SEM. Results and discussionResults showed that Cd, Ni, and Pb predominantly occurred in the weak acid soluble fraction (F1), residual fraction (F5), and sulfide-bound fraction (F4), respectively; Cu and Zn were mainly obtained in F4 and F5. Based on the distribution of indicator elements for metal fractions, the SEM from AVS extraction included different yields of non-residual and residual fractions besides the sulfidic fraction. Estimates for potential heavy metal toxicity based on NR metals of the SE procedure were thus based on a better-defined speciation compared to the simplistic approach of the AVS-SEM method. ConclusionsBased on the contents of NR metals and normalizing them by organic matter content, toxic effects are not expected for any of the sampling sites, irrespective of the presence or absence of mariculture. Using Pearson correlation analysis to identify predominant fractions influencing toxicity, we conclude that toxicity of heavy metals in anoxic sediments can be well predicted by their non-residual heavy metal contents. 相似文献
2.
Journal of Soils and Sediments - Trace metals accumulate in the food web and can pose high risks to human health and aquatic biota. We investigated seasonal and spatial variations of Cu, Zn, Pb,... 相似文献
3.
Journal of Soils and Sediments - Article with DOI 10.1007/s11368-018-2062-8, written by N. L. B. Kouassi et al., was originally published electronically on SpringerLink on 23 June 2018 with open... 相似文献
4.
Background, Aim and Scope. The compositional study of suspended matter in water from rivers of different latitudes and climates has revealed that the
fine fraction reflects both substrate lithology from source areas or topsoil composition along the course. Metal distribution
patterns are also strongly related to the clay mineral fate in fluvial aquatic systems. For the particular case of the coastal
area of the Río de la Plata estuary in South America, previous studies have, on the one hand, focused on the analysis of distribution
patterns of heavy metals in bottom river sediments and, on the other hand, on the assessment of metal contents in topsoils.
The present study was conducted to evaluate the Cu, Pb and Zn distribution in soils and sediments from four drainage basins
crossing two differentiated geomorphologic units composed of unconsolidated materials and to understand the metal behaviour.
Methods Data used included the existent, self-produced soil and sediment data sets (grain size, organic matter and Cu, Pb and Zn contents
from 124 samples). Analyses were performed by using standardised methods: grain size analysis by sieving and settling; organic
matter content based on the reduction of dichromate ion followed by titration; metal content by atomic absorption spectrophotometry
following acid digestion. Results and Discussion. The average (% w/w) clay and organic matter content were 45.9 ± 17.1 and
1.5 ± 1.7 for sediments and 32.0 ± 19.8, and 7.5 ± 7.6 for soils, respectively. The raw mean metal concentrations (mg-kg -1 dry weight) for sediments and soils were: Cu: 28.02 ± 27.28, 32.08 ± 21.64; Pb: 32.08 ± 46.94, 68.44 ± 69.25 and Zn: 83.09
± 150.33, 118.22 ± 74.20, respectively. A good correlation for each clay-normalised metal concentration was found between
soil and sediments using regression analysis considering average data for each basin sampling site (r > 0.89, p < 0.05). A
comparison between metal concentration levels taking into account geomorphologic units by a t independent sample test showed significant differences for the normalised soil-sediment metal data (p < 0.001), responding
to differences in grain size, clay mineralogy, organic matter and neoformed Fe-Mn oxide composition.
Conclusion, Recommendation and Outlook A clear parenthood between the topsoils and the bottom sediments in the study area was found. The Argiudolls from the inner
zone are frequently affected by rainwater erosion, which washes the fine materials with sorbed metals and carries them to
the streams. These watercourses reach the flat coastal plain, where soil flooding and bottom sediment depositional processes
predominate. Here, both soils and bottom sediments are enriched in clay, organic matter and metals. The topography and lithology,
under the environmental conditions of a temperate and humid climate control the fate of metals within these small basins.
The influence of the physical media on the distribution and fate of pollutants should not be minimised in the understanding
of the governing processes from natural systems. 相似文献
5.
For the purpose of studying the contamination, bioaccumulation and transfer of heavy metals and understanding the effects of soil properties on these, the work was carried out on a regional scale. A total of 30 sets of soil and pairing rice tissues samples (root, straw and grain) were collected in Xiangzhou of Guangxi, China; soil properties and Cd, Cu, Pb and Zn of different rice tissues were analyzed. The mobility and bioaccumulation of Cd, Cu, Pb and Zn were assessed by transfer coefficients and bioaccumulation factors of them. The results indicated that the excess proportions of Cd and Pb were 50%, 3.33% and 30%, 6.67% in soil and rice grain, respectively, according to Chinese maximum permitted concentrations of heavy metals. Cd and Zn showed stronger bioaccumulation and mobility capability; the bioaccumulation and transfer of Cu were slightly lower than Cd and Zn; Pb had the weakest mobility. The bioaccumulation and mobility of heavy metals from soil to rice were restrained by soil pH, CaO, SOC, Fe oxides and Mn. 相似文献
6.
Journal of Soils and Sediments - The aim of the study was to (1) investigate the distributions of sulfur (S), iron (Fe), and phosphorus (P) in coastal surface sediments under the stresses of high... 相似文献
7.
PurposeCurrently, the distribution characteristics and transport processes of the radionuclides 137Cs and 239?+?240Pu in the sediments of estuaries are still a controversial issue. Thus, in the present study, we investigated the distribution characteristics, sources and migration path of 137Cs and 239?+?240Pu in sediment cores of the Liao River estuary (LRE), China, and evaluated the relative contributions of the Pacific Proving Grounds (PPG) and riverine sources of Pu for the sediments in this area. We used 137Cs and Pu isotopes for dating the sediments and estimated the sedimentation rates by the two radionuclides in the LRE. Materials and methodsSeven sediment samples were collected using a box corer from the Liao River estuarine wetland and tidal flat in the LRE in October 2012 and April 2015, respectively. The activities of 137Cs in the various samples were determined by γ spectrometry using HP-Ge detectors with 60% relative counting efficiency. Approximately 2–5 g of sediment were spiked with 242Pu (ca. 1 mBq) as a chemical yield tracer for Pu isotopic analysis at the School of Radiation Medicine and Protection, Soochow University. The measurement of Pu isotopes (239Pu, 240Pu, 242Pu) was performed by a sector field ICP-MS. In order to quantitatively differentiate the relative proportions of global fallout and PPG, we employed a two-end member mixing model to estimate their contributions. Results and discussionThe average values of 137Cs, 239?+?240Pu activity concentrations, and 240Pu/239Pu atom ratios in the surface sediment samples of the LRE were 6.727?±?0.251 mBq g?1, 0.294?±?0.024 mBq g?1, and 0.188?±?0.049 (1σ), respectively. The average 240Pu/239Pu atom ratios ranged from 0.180?±?0.034 to 0.199?±?0.021 in sediment cores from the east and west sides of the LRE. For core LT-2 values for 137Cs and 239?+?240Pu concentrations were from below the detection limit: 3.380?±?0.414 and 0.036?±?0.007 to 0.105?±?0.007 mBq g?1. The mean 240Pu/239Pu atom ratio 0.217?±?0.050 (1σ) in sediment core LT-2 lies between the global fallout and PPG close-in fallout. ConclusionsWe found that atmospheric fallout is the main source of Pu in sediment cores from the east and west sides of the LRE. For core LT-2, atmospheric fallout and riverine input (~?73.4%) are the major sources of Pu with the source of the rest of Pu (~?26.6%) attributed to the PPG via the Tsushima Warm Current and the coastal water of the East China Sea. The sedimentation rates (means 0.62–0.8 cm year?1) estimated by the two radionuclides were in good agreement and without any statistically significant difference. 相似文献
8.
Purpose This work explores the application of the use of Zn, Cu, and Pb relative contents as a new type of normalization method for geochemical properties of soils and sediments in an Atlantic Basin (Anllóns River, NW Spain). The method is based on the conservative behavior of these elements, which exhibit a certain concentration ratio that remains stable as long as there are no human disturbances. Materials and methods The average relative contents of Zn, Cu, and Pb were calculated by dividing the concentration of each metal in soils or sediments, in the <63-μm fraction, by the sum of Zn, Cu, and Pb, expressed as a percentage. The evaluation of the sum of the average relative concentrations of Zn, Cu, and Pb ( Ri), together with three standard deviations for each element, namely, Ri ± 3Si, allows a hexagon to be constructed, represented in ternary diagrams of Zn:Cu:Pb. Following the method proposed by Weng et al. (Environ Geol 45:79–85, 2003), those samples falling outside the hexagon must be considered outliers. Results and discussion Results obtained confimed the conservative behavior between the relative contents of Zn, Cu, and Pb in surficial samples (soils, bed, and suspended sediments). Only sediment cores displayed nonconservative behavior, showing a marked Pb enrichment, with respect to the surficial samples. When Zn, Cu, and Pb relative contents were plotted in ternary diagrams, outliers were best classified when the hexagon was drawn with standard deviations of samples from the study area. The hexagon drawn with an international database of soils and sediments showed a poorer classification of outliers. Conclusions The results showed that total Zn, Cu, and Pb relative contents may be employed to investigate anthropogenic disturbances of these elements in soils and sediments of the Anllóns River Basin, thus corroborating that this type of normalization may be employed as a tool to assess outliers in a contaminated area. 相似文献
9.
Intention, Goal, Scope, Background Environmental pollution caused by oil spills is a major ecological problem. Oil contamination in the environment is primarily
evaluated by measuring the chemical concentrations of hydrocarbons. The results of chemical analyses are important for estimating
water and sediment quality in the risk assessment to the flora and fauna of oil-contaminated sites. In the world there are
lake ecosystems under permanent chemical stress due to urbanization and the oil industry. Studies, however, have been generally
limited to petroleum compounds and have not considered other pollutants of the site like PCBs, polychlorinated pesticides
and heavy metals.
Objective Water and sediment from stations in the Mecoacán Lake in the Mexican State of Tabasco were analyzed for polycy-clic aromatic
compounds (PAHs), aliphatic hydrocarbons (AHs), polychlorinated biphenyls (PCBs), polychlorinated pesticides (PCPs) and heavy
metals. The objective of this study was to examine the contaminant levels of the samples collected in February 1993 and 1996
after oil spills at the Mecoacán petroleum region. The goals of this study were to reveal the effect of the spills on the
distribution of the hydrocarbons and assess the toxi-cological significance of the levels found. In addition, our aim was
to examine the distribution of the PAHs in sediments from Mecoacán originated from both pyrolytic and petrogenic sources.
Methods Samples were collected from 19 stations and prepared according to the CARIPOL (Caribbean Pollution) methodology of the United
Nations Environmental Programme (1992) of the Great Caribbean Region for hydrocarbons in marine and coastal water, and sediments.
The gas-chromatographic and atomic absorption analysis of the samples was performed after sampling.
Results and Discussion Concentrations of PAHs in water ranged from 0.2 to 0.8 μg/l in 1993 and from 0.3 to 2.8 μg/l in 1996. The concentration of
the 16 EPA-PAHs varied from 0.1 to 36 mg/kg dry weight in the lake sediment samples collected in 1996, while those of AHs,
PCBs and PCPs ranged from 0.1 to 67 mg/kg, 0.1 to 59 μg/kg and 6 to 370 μg/kg, respectively. The most abundant contaminants
in water were benz[a]anthracene and pyrene, in 1993 and 1996, respectively; while in sediments collected in 1996: Pyrene,
C 24, 2-chlorobiphenyl and endrin predominated. Heavy metals (Cu, Pb and Zn) were found at low concentrations. Benzo[a]pyrene
was detected in some sediment samples in varying amounts (0.2 to 0.3 mg/kg).
Conclusions The maximum total PAH concentration in sediments was found at sites near the oil fields and the AH concentration near the
urban zone. The mayor pollutants in sediments were PAHs and AHs, and taking into regard the detected PAHs near the oil fields,
the source was the oil spilling. The mean total PAH value in Mecoacan sediments of 6.4 mg/kg did not exceed the median range
effects value (ERM) for total PAHs of 44.8 mg/kg. The measured organochlorine compounds and heavy metals were present in amounts
much inferior to the ERM values. This study confirms that contaminants concentration in sediments did not exceed the environmental
quality guideline for the 50% probability and no adverse effect can be expected.
Recommendation and Outlook Analysis revealed no indication of a contribution of PAHs, PCBs, PCPs and heavy metals to acute sediment toxicity. The results
of this study demonstrate the importance of continuous monitoring of ecosystems exposed to pollution to make pre-spill data
available in order to evaluate the real consequence of the spilling and its effect on flora and fauna. 相似文献
10.
Following previous research on lemon juice enriched with berries, the aim of this work was to design new blends based on lemon juice mixed with different edible berries of exotic and national origin: maqui ( Aristotelia chilensis (Molina) Stuntz), a?a?? ( Euterpe oleracea Mart.), and blackthorn ( Prunus spinosa L.). The phytochemical characterization of controls and blends was performed by HPLC-DAD-ESI/MS(n). Their antioxidant capacity against DPPH, superoxide, and hydroxyl radicals and hypochlorous acid and their potential to inhibit cholinesterases were also assessed. The profiling of the red fruits and lemon revealed a wide range of bioactive phenolics. The novel beverage based on lemon juice and maqui berry (LM) was the most interesting blend in terms of antioxidant capacity. Berry control samples displayed reduced effects on acetylcholinesterase and butyrylcholinesterase, the lemon juice control being always the most active. This activity was also remarkable for lemon-blackthorn (LB) and lemon-a?a?? (LA) blends, the last being the most effective inhibitor of cholinesterases among all samples. The results suggested that lemon juice enriched with berries could be of potential interest in the design of new drinks with a nutritive related function on health for chronic diseases. 相似文献
11.
The agricultural destination of sewage sludge promotes the return of organic matter and nutrients to the soil, prevents contamination and degradation of hydric resources, and contributes to food and fiber production. In Brazil, the Resolution of the National Environment Council (Conama 375/06) and in the State of Paraná the Resolution of the State Environment Cabinet (Sema 021/09) established criteria and procedures for agricultural use of sewage sludge seeking to avoid risk to public health and the environment. This case study attempts to present the results of the destination of the sludge generated in the Sludge Management Units (SMU) in Curitiba Metropolitan Region (CMR), State of Paraná, Brazil from 2007 to 2010. Data analysis of agronomic parameters and inorganic substances (metals) of 99 batches of sewage sludge destined for agricultural use, based on 239 agronomic projects, was performed. The comparison of the characteristics of the batches generated in anaerobic and aerobic SMUs of CMR was also conducted. During the study, 88,166 t of sludge (33,404 dry tons) were destined for 2,288 ha of agricultural areas. The sludge provided 88 % of the lime, 74 % of N, 73 % of P 2O 5, and 35 % of K 2O for fertilizing the corn, soybean, bean, oat, wheat, green manure, and in the implementation and postharvest of stone fruit trees. The 80 benefited farmers reduced expenses with fertilizers and limestone, saving an average of US$813.45 per ha. 相似文献
12.
PurposeThe objectives of this study were to investigate the abundance and composition of the superficial biofilm on the bed sediments of the Anllóns River (NW Spain), to evaluate the relationships between biochemical parameters and biological methods based on identification and counting, and to explore the relationships between biofilm growth and the properties of the sedimentary habitat, mainly the trophic state.Materials and methodsBed sediment samples (0–5 cm) were collected in two different seasons (winter and summer) at four sampling sites along the river course. Physicochemical properties of pore waters and sediments were determined. Biological properties included the determination of dehydrogenase activity (DHA) and phytopigment (Chl a Chl b and total carotenoids) concentrations, as well as taxonomic identification. For taxonomic identification, two sampling methods were compared: the Pasteur pipette method and a mini-corer method. Total and relative algal abundances (TA and RA, respectively) and genus richness were calculated. The relationships between the different variables were examined using Pearson correlations and principal component analysis.Results and discussionThe main taxa belonged to Chlorophyta, Cyanophyta, Euglenophyta, and Heterokontophyta. The most abundant class was Bacillariophyceae, which represents >86 % of the total abundances in the superficial sediments. The highest total algal abundance and genus richness were observed in summer at the river mouth, where DHA and phytopigment concentrations were also the highest. The statistical analysis revealed positive correlations between TA and the biochemical parameters (DHA and phytopigments) as well as positive relationships of these three parameters with the physicochemical properties of the sediments, such as electrical conductivity, and the concentrations of fine particles, C, N, S, and total P.ConclusionsThe results of this study reveal the positive relationships between the biochemical properties (phytopigments and respiratory activity) and total algal abundances determined by taxonomic identification and counting. All of these properties presented evidence of a clear influence of the nutrients and organic matter contents of the sediments, pointing to the importance of the site conditions, particularly the trophic state, in the development of benthic microflora. 相似文献
13.
Journal of Soils and Sediments - River channel sediments have been widely used to trace current and historical pollution in fluvial systems, although they are not the only media employed for that... 相似文献
14.
OBJECTIVE: To identify individual and contextual factors associated with the practice of exclusive breast-feeding (EBF). METHODOLOGY: We analysed 34 435 children under 6 months of age living in 111 municipalities in the state of S?o Paulo, south-eastern Brazil, who participated in a survey investigating feeding practices during the first year of life, carried out during the 1999 national vaccination campaign. The questionnaire employed included questions on the consumption, in the last 24 h, of breast milk, water, tea, other types of milk and other foods, in addition to mother and child characteristics. Information on the pro-breast-feeding measures implemented in the municipalities was also collected. The effects of individual and contextual characteristics on EBF were analysed using multilevel models. RESULTS: The final model showed a greater chance of EBF in women with tertiary education (odds ratio (OR) = 1.91; 95% confidence interval (CI) 1.75-2.06); women aged between 25 and 29 years (OR = 1.52; 95% CI 1.41-1.63); multiparae (OR = 1.42; 95% CI 1.33-1.49); female babies (OR = 1.12; 95% CI 1.05-1.18); birth weight > or = 3000 g (OR = 1.73; 95% CI 1.49-1.97); child follow-up in the private health-care network (OR = 1.10; 95% CI 1.02-1.18); and municipalities with four or five pro-breast-feeding measures (OR = 2.4; 95% CI 2.19-2.88). An analysis of the interactions between individual and contextual variables showed that the presence of at least four pro-breast-feeding measures in the municipality attenuated the risk of early termination of EBF associated with low maternal schooling and low birth weight, and transformed child follow-up in the public network into a protective factor against the early termination of breast-feeding. CONCLUSIONS: The presence of measures aimed at protecting, promoting and supporting breast-feeding in the municipality had a positive influence on EBF and attenuated the impact of risk factors for the termination of breast-feeding. 相似文献
15.
The salinization process was investigated with hydrogeochemical tools to evaluate the origin of salinity in the Selçuk Plain. Na/Cl and Cl/Br molar ratios of coastal zone that covers an alluvial aquifer, karstic discharges, and a wetland are similar to the local seawater ratio. According to mixing ratios, seawater addition can reach 9–18% in both seasons at the coastal zone especially in karstic springs that are a kind of seawater–freshwater mixing points. A thematic map of the Salinization zone was constructed for the Selçuk Plain using geographical information system tools with different parameters such as major ion ratios, EC values, mixing ratios, and sodium adsorption ratio values. High correlation between Cl and Br, B, Li and Sr explains the salinization process that comes from marine intrusion. The δ 18O and δD composition of water samples varies between ?6.7‰ and ?2.9‰; ?37‰ and ?20‰, respectively. The coastal zone waters are plotted on the mixing line due to the effects of the salinization process in the plain. 相似文献
17.
Journal of Soils and Sediments - The overexploitation of resources such as mining and metallurgical and agricultural resources has resulted in heavy metal accumulation and soil acidification.... 相似文献
18.
This work aims to evaluate the soil physical properties affected by cover crop rotation and soil management in a long-term experiment in southern Brazil. The experiment was established in 1986, with treatments combining six winter treatments and two tillage systems (conventional and no tillage). Bulk density, porosity, aggregate-size class distribution, and organic carbon content of the aggregates were determined at six depths. Bulk density was not affected by tillage systems and winter treatments. The soil disturbance by plowing enhanced the macroporosity, decreased the microporosity, and promoted the formation of smaller aggregate size, in comparison to no tillage. Apart from the soil management, all winter species increased the greater aggregate-size classes, mean weight diameter, geometric mean diameter, and aggregate stability index compared to the fallow treatments. At the no-till treatments, the greater part of sequestered carbon into the soil was stored into the lower and bigger soil aggregates. 相似文献
19.
Bovine chymosin constitutes a traditional ingredient for enzymatic milk coagulation in cheese making, providing a strong clotting capacity and low general proteolytic activity. Recently, these properties were surpassed by camel chymosin, but the mechanistic difference behind their action is not yet clear. We used capillary electrophoresis and reversed-phase liquid chromatography-mass spectrometry to compare the first site of hydrolysis of camel and bovine chymosin on bovine κ-casein (CN) and to determine the kinetic parameters of this reaction (pH 6.5; 32 °C). The enzymes showed identical specificities, cleaving the Phe105-Met106 bond of κ-CN to produce para-κ-CN and caseinomacropeptide. Initial formation rates of both products validated Michaelis-Menten modeling of the kinetic properties of both enzymes. Camel chymosin bound κ-CN with ~30% lower affinity (K(M)) and exhibited a 60% higher turnover rate (k(cat)), resulting in ~15% higher catalytic efficiency (k(cat)/K(M)) as compared to bovine chymosin. A local, less dense negatively charged cluster on the surface of camel chymosin may weaken electrostatic binding to the His-Pro cluster of κ-CN to simultaneously impart reduced substrate affinity and accelerated enzyme-substrate dissociation as compared to bovine chymosin. 相似文献
20.
Two environmental relief compartments from Sinos Valley, Rio Grande do Sul State, Brazil, interpreted in the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images, are contaminated, in different ways, by two industrial landfills. One of the landfills is located in a fluvial plain with thin superficial sediments made of expansive clays. In this landfill, metals like Cr, Co, Ni, Cu, Pb, Zn, and Ba, have concentrated more than that of other landfill, which is located on a low hill in a sedimentary arenitic terrain. The metals have also accumulated in plant tissues in the investigated areas. Plants have accumulated more Mn, Zn, Ba, and Cu. 相似文献
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