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1.
Distribution of trace elements in the coastal sea sediments of Maslinica Bay, Croatia 总被引:1,自引:0,他引:1
Nenad Mikulic Visnja Orescanin Loris Elez Ljiljana Pavicic Durdica Pezelj Ivanka Lovrencic Stipe Lulic 《Environmental Geology》2008,53(7):1413-1419
Spatial distributions of trace elements in the coastal sea sediments and water of Maslinica Bay (Southern Adriatic), Croatia
and possible changes in marine flora and foraminifera communities due to pollution were investigated. Macro, micro and trace
elements’ distributions in five granulometric fractions were determined for each sediment sample. Bulk sediment samples were
also subjected to leaching tests. Elemental concentrations in sediments, sediment extracts and seawater were measured by source
excited energy dispersive X-ray fluorescence (EDXRF). Concentrations of the elements Cr, Cu, Zn, and Pb in bulk sediment samples
taken in the Maslinica Bay were from 2.1 to over six times enriched when compared with the background level determined for
coarse grained carbonate sediments. A low degree of trace elements leaching determined for bulk sediments pointed to strong
bonding of trace elements to sediment mineral phases. The analyses of marine flora pointed to higher eutrophication, which
disturbs the balance between communities and natural habitats. 相似文献
2.
Spatial distribution of major and trace elements in shallow reservoir sediments: an example from Lake Waco, Texas 总被引:7,自引:4,他引:7
J. Abraham 《Environmental Geology》1998,36(3-4):349-363
Sediment geochemistry of a shallow (6-m average) reservoir (Lake Waco) was evaluated for the spatial distribution of major
and trace elements. Sixty bottom and core samples along a 21-km transect within the reservoir, 18 overbank sediment samples,
and 8 rock types in the drainage area were collected and analyzed for major (Al, Ca, Fe) and trace elements (As, Ba, Cr, Cu,
Hg, Mn, Ni, Pb, Sr, V, Zn). Elemental concentrations in the reservoir sediments closely correspond to concentrations in the
regional rocks and represent a mixture of overbank sediment composition of the tributaries. Elemental concentrations were
statistically regressed against Al concentrations in order to establish regional baseline levels and thereby distinguish natural
from anthropogenic sources. Spatial geochemical trends, considered in terms of element-to-Al ratio versus V-to-Al ratio, relate
to the natural and anthropogenic sources contributing to the elemental concentrations. The spatial elemental distribution
in the reservoir, which receive sediments from two mineralogically contrasting basins, reflect textural and mineralogical
transition within the reservoir and suggest a progressive mixing of sediment from the tributaries. The spatial elemental distribution
and sediment texture suggest that the sediment-source, which determines the sediment-type, has a greater influence on the
major- and trace-element distributions in shallow reservoir sediments than bathymetry.
Received: 25 September 1997 · Accepted: 3 February 1998 相似文献
3.
The marine coastal sediments from Togo have been analysed for the trace elements Cd, Cr, Cu, Ni, Pb, Sr, V, Zn and Zr to
ascertain the geo-ecological impact of dumping of phosphorite tailings into the sea. Trace element concentrations ranged from
2–44 ppm for Cd, 22–184 ppm for Cu, 19–281 ppm for Ni, 22–176 ppm for Pb, 179–643 ppm for Sr, 38–329 ppm for V, 60–632 ppm
for Zn and 18–8928 ppm for Zr. Regional distribution of trace elements in the marine environment indicates that the concentrations
of Cr, Cu, Ni, Pb, V, Sr and Zn increase seawards and along the coastal line outwards of the tailing outfall, whereas Cd and
Zr showed reversed spatial patterns. Sorting and transport of phosphorite particles by coastal currents are the main factors
controlling the distribution of particle-bound trace metals in the coastal environment. The Cd, Sr and Zn concentrations decrease
with decreasing grain size in marine coastal sediments, whereas Cr, Cu, Ni and Zn concentrations increase with decreasing
grain size. Percolation and shaking experiments were carried out in laboratory using raw phosphate material and artificial
sea water. Enhanced mobilization of Cd from phosphorites by contact with the sea water was observed.
Received: 11 May 1998 · Accepted: 20 October 1998 相似文献
4.
As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Se and Zn concentrations were determined and compared in lake and overbank sediments
from 33 catchments without local pollution sources in southern Norway. There were no significant differences in concentrations
of Be, Co, Cr, Cu, Ni, and V in overbank and pre-industrial lake sediments. In areas with shallow overburden, and significant
influence from long-range atmospheric pollution, concentrations of As, Cd, Hg, Pb, Se, and Zn in overbank sediments were probably
modified by vertical percolating water. In such areas, we suggest using lake sediments as a better sampling medium for mapping
pre-industrial concentrations. Pre-industrial lake sediments yield natural concentrations of Hg and Se, which consist of both
geogenic and natural atmospheric deposition. Important covariables like organic carbon content, Fe oxides, and fine mineral
fraction were generally higher in pre-industrial lake sediments as compared to overbank sediments. By adjusting for such differences
overbank sediments could be used as an alternative in mapping background concentrations of trace metals in regions with few
lakes.
Received: 19 February 1999 · Accepted: 17 April 1999 相似文献
5.
Geochemical variations of major and trace elements in recent sediments,off the Gulf of Mannar,the southeast coast of India 总被引:3,自引:0,他引:3
The Gulf of Mannar along the Tuticorin coast is a coral base of the southeast coast of India. To obtain a preliminary view of its environmental conditions, geochemical distribution of major elements (Si, Al, Fe, Ca, Mg, Na, K, P), trace elements (Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) and acid leachable elements (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) were analyzed in surface sediment samples from two seasons. Geochemical fractionation confirmed the lithogenic origin of metals, which were mainly associated with the detrital phase. The sediments in the gulf are sandy with abundant calcareous debris, which controls the distribution of total and acid leachable elements. Enrichment factors relative to crust vary by a magnitude of two to three and the presence of trace metals indicates the input of Cr, Pb, Cd, Cu and Zn in both forms through industrial activities. Factor analysis supports the above observation with higher loadings on acid leachable elements and its association with CaCO3. The increase in concentration of trace metals (Cr, Pb, Cd, Cu, Co, Ni, Zn) along the Gulf of Mannar indicates that the area has been contaminated by the input from riverine sources and the industries nearby. The present study indicates that other sources should be evaluated in the long-term monitoring program. 相似文献
6.
贵州清镇蔡家坝铝土矿床赋矿层位为下石炭统九架炉组(C1jj),下伏地层中-上寒武统清虚洞组(∈2-3q)。本研究以九架炉组含铝岩系与顶底板为主要研究对象,通过对Be、Th、U、Sr、Ba、V、Ni、Cr、Zr等沉积环境指示性较强的微量元素以及稀土元素测试分析,结合Th/U、Ni/Cr、Sr/Ba等二元图解和稀土元素标准化图解综合研究,探讨研究区铝土矿床的物质来源、成矿环境及稀土分异控制因素。研究结果表明:1)研究区铝土矿床形成于以陆相沉积为主,海陆交互的还原环境,成矿作用为风化—沉积成因,有异地沉积等成矿物质多源特征,下伏中-上寒武统清虚洞组为矿区物源之一; 2)研究区含铝岩系ΣREE值最高831.63×10-6,ΣLREE/ΣHREE比值为4.68~13.77,表现为轻稀土富集型;3) pH值、粘土矿物以及Fe矿物可能共同主导了蔡家坝含铝岩系中REE的富集以及LREE和HREE的分异。 相似文献
7.
D. Ciszewski 《Environmental Geology》1997,29(1-2):50-57
The influence of sources of effluents on pollution of bottom sediments of the small Chechło River (23 km long, mean discharge
1.5 m3 s–1) in southern Poland was examined through analysis of heavy metals distribution in transverse and longitudinal cross sections.
Underground waters from a Pb–Zn mine cause very high concentrations of Zn, Cd, and Pb in both fractions investigated (<1 mm
and <0.063 mm) of sediments in the active channel zone, whereas sedimentation of huge amounts of suspended matter discharged
from oil refinery cause concentrations of heavy metals in fine fractions rather uniform in cross sections. In the lowest reach,
with relatively reduced contamination, the highest concentration both in fine and coarse fractions occurs close to the river
banks and in the deepest points of the channel. The lowest concentrations have been found at the points of strongest reworking
and accumulation of sandy material in the riverbed.
Received: 25 April 1995 · Accepted: 11 September 1995 相似文献
8.
A baseline might be used as a point of reference to monitor change from some specific data without concern for whether the
baseline determination is natural or has been changed by human activity. We selected 326 sediment samples from Dexing area,
South China, and analyzed for 17 chemical elements. The geochemical baseline was predicted with the method of the normalization
procedure combined with the relative cumulative frequency curve. The results indicate Al was the best reference element for
the normalization procedure among four potential reference elements (Al, Fe, Ti, and Mn). The baseline value range obtained
from the normalization procedure method included both the regional geochemical background of the sediment and the median value
of the measured contents. The median value of baselines obtained from relative cumulative frequency method was lower than
that obtained from normalization procedure method. In contrast to the geochemical patterns of heavy metals in 1987, the spatial
distribution of anomalies sprawled in 2004 in study area, especially for Cu, Pb, Zn, Cd, As, Fe, and Cr. 相似文献
9.
Recent sedimentary history of natural environmental change and anthropogenic influence in an ephemeral river catchment has
been reconstructed using selected major and trace elements, element ratios, and their different geochemical phases (Tessier sequential extraction methods), pollen, and grain size combined with 210Pb- and 137Cs-dating method in marsh sedimentary cores. Attempts were made to use selected element ratios with different geochemical
phases—residual phase of Ti, Al, V, Cr, Ni, Rb, K, Sr, and Ba; mobile Sr and Ba—combined with 210Pb- and 137Cs-chronology to interpret certain time information of environmental changes saved within the marsh sediments. Results indicate
that there were two marked humid periods during 1850–1860 ad and 1890–1920 ad, and sand storm activities prevailed during 1920–1930 ad. After about 1900 ad, soil erosion has increased with the extensive agricultural activities in the Huolin River catchments, and further intensified
after 1950s. After 1980, soil erosion has become even more intense, which is consistent with the reinforcement of human activities,
the drastic loss of vegetation cover in the upstream lands, especially, the exploitation of the open cast coalmine in the
upstream of Huolin River at that time. Influenced by the inundation of the Huolin River, the heavy metal pollution historical
trends in Xianghai marsh wetland could be roughly divided into three periods by analysis of sediment enrichment factor (KSEF) and the index of geoaccumulation (I
geo):1760–1880 ad, 1880–1980 ad, and 1980–now. Human activities accelerate the inputs of heavy metal, which leads to degradation of the marsh. This study
also investigated on source of marsh sediments (by Ti/Al), redox condition [by V/Cr and V/(V + Ni)], and salinization indicators
(by Sr/Ba and Rb/K). The results demonstrate that sources of sediments and redox conditions were partly similar for both riparian
and depressional marshes. Besides, some differences in degree of salinization between two types of marsh were also identified,
especially after 1880. 相似文献
10.
Geographical variations of trace elements in sediments of the major rivers in eastern China 总被引:10,自引:0,他引:10
A total of 26 geographically and hydrologically diverse sediment samples were collected from 12 major rivers in eastern China.
The <63-μm fraction of the sediments was analysed for both total concentrations of Cu, Zn, Pb and Cd, and their associations
with various geochemical phases. The geographical variations of sediment-bound trace metals can be related to the bedrock
types and weathering processes in the corresponding river basins. The rivers in southern China had notably higher concentrations
of trace metals in sediments because of abundant non-ferrous mineral deposits and stronger weathering process in the region.
A large proportion of trace metals in these sediments was associated with iron and manganese oxides and organic matter. Relative
low levels of trace metals were found in river sediments in northern China, and a significant proportion of the metals was
bound to organic matter, carbonates, and the residual fraction. The sediments in the Yellow River, originating from special
loess, had the lowest concentrations of trace metals. Most of the trace metals were associated with the carbonates and residual
phases.
Received: 24 March 2000 · Accepted: 11 July 2000 相似文献
11.
Dariusz Ciszewski 《Environmental Geology》1998,36(1-2):45-54
An evaluation of the influence of channel processes (erosion, accumulation, processing of channel sediments) on the dispersal
of heavy metals in bottom sediments was carried out in the channels of the Sztoła and Biała Przemsza rivers in Upper Silesia,
Poland. These rivers receive waters from a Zn and Pb mine. Mine waters transport a large amount of fine-grained sediments
contaminated with heavy metals. The polluted material is accumulated in these stream courses and mixed with nearly homogeneous
sandy sediment derived from erosion of the river banks and bed. Because these alluvia are easily set in motion, the distribution
of heavy metal concentration in the channel in fraction <1 mm reflects differences in physical processes of sedimentation
in its cross-section. The minimal values in active channel and maximal in the near-bank zone are typical for those channel
sections where heavy metals, present in a solid state, are transported as a suspended load (normally the largest part of a
polluted river course). In short sections heavy metals associated with the grains of a large mass which has accumulated in
the active channel are transported as a bed load and the typical distribution pattern is reversed (in fractions both <1 mm
and <0.063 mm). Such regularities can be disturbed in localities where strong, turbulent flow or frequent eddying occur and
Mn oxides and hydrooxides and associated elements precipitate. The smallest variation in heavy metal concentration in the
homogenous, fine-grained bank sediments which are trapped by plants below water level is a feature which recommends these
localities as being the most suitable for monitoring of river pollution.
Received: 11 November 1997 · Accepted: 12 March 1998 相似文献
12.
B. G. Lottermoser 《Environmental Geology》1998,36(1-2):118-126
Heavy metal and metalloid concentrations within stream-estuary sediments (<180-μm size fraction) in north-eastern New South
Wales largely represent natural background values. However, element concentrations (Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Zn)
of Hunter River sediments within the heavily industrialized and urbanized Newcastle region exceed upstream background values
by up to one order of magnitude. High element concentrations have been found within sediments of the Newcastle Harbour and
Throsby Creek which drains into urbanized and light industry areas. Observed Pb enrichments and low 208Pb/204Pb, 207Pb/204Pb and 206Pb/204Pb ratios are likely caused by atmospheric deposition of Pb additives from petrol and subsequent Pb transport by road run-off
waters into the local drainage system. Sediments of the Richmond River and lower Manning, Macleay, Clarence, Brunswick and
Tweed River generally display no evidence for anthropogenic heavy metal and metalloid contamination (Ag, As, Cd, Cr, Cu, Hg,
Ni, Pb, Sb, Zn). However, the rivers and their tributaries possess localized sedimentary traps with elevated heavy metal concentrations
(Cu, Pb, Zn). Lead isotope data indicate that anthropogenic Pb provides a detectable contribution to investigated sediments.
Such contributions are evident at sample sites close to sewage outlets and in the vicinity of the Pacific Highway. In addition,
As concentrations of Richmond River sediments gradually increase downstream. This geochemical trend may be the result of As
mobilization from numerous cattle-dip sites within the region into the drainage system and subsequent accumulation of As in
downstream river and estuary sediments.
Received: 5 September 1997 · Accepted: 4 November 1997 相似文献
13.
Geochemical factors controlling the chemical nature of water and sediments in the Gomti River, India 总被引:3,自引:2,他引:1
R-mode factor analysis of the recently acquired data on water and sediment chemistry has been performed. Basic chemical parameters
have been merged together which aid in interpreting a few empirical geochemical factors controlling the chemical nature of
water and sediments of the Gomti River, a major Himalayan tributary of the Ganges drainage basin. Water chemistry seems to
be controlled by three factors: bicarbonate, rainfall and silicate and phosphate factors. Sediment chemistry is largely controlled
by the following four factors: clay, adsorption/desorption, Fe-Mn hydroxide and mercury factors. These factors show spatial
and temporal variability in terms of their R-scores.
Received: 8 September 1997 · Accepted: 15 December 1997 相似文献
14.
Paul-Dsir Ndjigui Paul Bilong Dieudonn Bitom Abdoulaye Dia 《Journal of African Earth Sciences》2008,50(5):305-328
The behaviour of major and trace elements have been studied along two serpentinite weathering profiles located in the Kongo-Nkamouna and Mang North sites of the Lomié ultramafic complex.The serpentinites are characterized by high SiO2 and MgO contents, very low trace, rare earth and platinum-group element contents. Lanthanide and PGE contents are higher in the Nkamouna sample than in Mang North. Normalized REE patterns according to the CI chondrites reveal that: (i) all REE are below chondrites abundances in the Mang North sample; (ii) the (La/Yb)N ratio value is higher in the Nkamouna sample (23.72) than in the Mang one (1.78), this confirms the slightly more weathered nature of the Nkamouna sample. Normalized PGE patterns according to the same CI chondrites reveal a negative Pt anomaly in the Mang sample. The Nkamouna sample is characterized by a flat normalized PGE pattern.All element contents increase highly from the parent rock to the coarse saprolite.In the weathering profiles, Fe2O3 contents decrease from the bottom to the top contrarily to Al2O3, SiO2 and TiO2. The contents of alkali and alkaline oxides are under detection limit.Concerning trace elements, Cr, Ni, Co, Cu, Zn and Sc decrease considerably from the bottom to the top while Zr, Th, U, Be, Sb, Sn, W, Ta, Sr, Rb, Hf, Y, Li, Ga, Nb and Pb increase towards the clayey surface soil. Chromium, Ni and Co contents are high in the weathered materials in particular in the saprolite zone and in the nodules.REE contents are high in the weathered materials, particularly in Nkamouna. Their concentrations decrease along both profiles. Light REE are more abundant than heavy REE. Normalized REE patterns according to the parent rock reveal positive Ce anomalies in all the weathered materials and negative Eu anomalies only at the bottom of the coarse saprolite (Nkamouna site). Positive Ce anomalies are higher in the nodular horizon of both profiles. An additional calculation method of lanthanide anomalies, using NASC data, confirms positive Ce anomalies ([Ce/Ce*]NASC = 1.15 to 60.68) in several weathered materials except in nodules ([Ce/Ce*]NASC = 0.76) of the upper nodular horizon (Nkamouna profile). The (La/Yb)N ratios values are lower in the Nkamouna profile than in Mang site.PGE are more abundant in the weathered materials than in the parent rock. The highest contents are obtained in the coarse saprolite and in the nodules. The elements with high contents along both profiles are Pt (63–70 ppb), Ru (49–52 ppb) and Ir (41 ppb). Normalized PGE patterns show positive Pt anomalies and negative Ru anomalies.The mass balance evaluation, using thorium as immobile element, reveals that:
- – major elements have been depleted along the weathering profile, except for Fe, Mn and Ti that have been enriched even only in the coarse saprolite;
- – all the trace elements have been depleted along both profiles, except for Cr, Co, Zn, Sc, Cu, Ba, Y, Ga, U and Nb that have been enriched in the coarse saprolite;
- – rare earth elements have been abundantly accumulated in the coarse saprolite, before their depletion towards the top of the profiles;
- – platinum-group elements have been abundantly accumulated in the coarse saprolite but have been depleted towards the clayey surface soil.
15.
Trace element chemistry of major rivers in Orissa State, India 总被引:1,自引:1,他引:1
K. O. Konhauser M. A. Powell W. S. Fyfe F. J. Longstaffe S. Tripathy 《Environmental Geology》1997,29(1-2):132-141
Geochemical analyses of surface waters from rivers flowing through Orissa State, India, indicated that trace element concentrations
were extremely variable and consistently higher than world river average. The Brahmani River was the most solute-rich river
studied, followed by the Baitarani and Mahanadi Rivers. Although all three rivers drain similar geology, the Brahmani River
catchment is heavily industrialized, and water samples collected upstream and downstream from industries indicated that anthropogenic
activity directly influenced its chemical composition. Samples collected from several towns, in all three river systems, did
not invariably show similar patterns, with various elements having higher dissolved concentrations upstream. Because the concentration
of total solids increased downstream, this implied that some components of the sewage had effectively sequestered available
elements from solution and converted them to particulate material. Although the impact of pollution is clearly recognizable
in water samples collected in proximity to the anthropogenic source, there are only slight elemental accumulations in the
lower reaches of the Mahanadi River, with no accumulation in the Brahmani River. Apparently for these large rivers, discharged
effluent becomes rapidly diluted, while complexation and sedimentation further removes trace elements from the water column.
However, in the less voluminous Baitarani River, elementar enrichment near the river's mouth suggests that in this secondary
river, where dilution effects are less, the concerns over regional water quality may be more prevalent.
Received: 1 April 1995 · Accepted: 30 August 1995 相似文献
16.
R. A. Klassen 《Environmental Geology》1998,33(2-3):154-169
In central Newfoundland (NTS 12A/10, 15, 16, 2H/1), As, Pb, and Zn concentrations in the clay-sized (<0.002 mm) and silt
and clay-sized (<0.063 mm) fractions of till reflect compositional differences among and within rock terranes at scales of
kilometers to tens of kilometers. In those fractions, till derived from volcanic bedrock of Victoria Lake Group (Tulks Hill)
is notably enriched in As (50–>1000 ppm), exceeding levels commonly set for purposes of environmental protection. Near Pb-Zn
mines at Buchans, geochemical variation with depth reflects the dispersal of detritus from mineralized bedrock, and differences
in sediment type and provenance. There, surface sediments are rich in granitic debris derived from the Topsails igneous terrane
5 km north of Buchans and contain low concentrations of trace metals. These sediments are compositionally unrelated to either
Buchans Group volcanic rock or an underlying, older till enriched in sulphide minerals and trace metals. Metal-rich till extending
up to 10 km southwest of Buchans results from combined glacial and debris flow transport related to two distinct geological
events. Trace metals are enriched (two- to fourfold) in the clay-sized fraction of till compared to the silt and clay-sized,
and are associated with Al- and Mg-bearing minerals that preferentially concentrate in the clay fraction. The geochemistry
of the silt and clay-sized fraction can approximate that of the <2-mm fraction. Background variations in till illustrate the
important role of a geological framework to the interpretation of geochemical surveys and the origins of trace metals in the
environment.
Received: 31 October 1996 · Accepted: 27 May 1997 相似文献
17.
Lateritic bauxites in the coastal lowlands of Suriname form part of a belt along the northern margin of the Guiana Shield that has long been one of the world's major bauxite producing regions. The Surinamese deposits, many of which with an extensive mining history, originated on Tertiary siliciclastic sediments and were mostly buried under a layer of young sediments. The bauxite-bearing sequences are generally topped with an iron-rich layer largely made up of hematite and goethite. It covers a gibbsite-rich bauxite horizon that passes downward into a kaolinitic bottom section containing anatase and zircon as main accessory minerals. Weathering profiles across formerly mined deposits were analyzed for geochemical and mineralogical properties aimed at exploring compositional diversity, underlying controls of bauxite-formation and the nature of precursor sediments.Studied profiles in different parts of the coastal plain reveal overall similarities between individual deposits in showing significant depletion of Si, K, Na, Mg and Ca and strong, primarily residual, relative enrichment of Al, Ti, Zr, Nb, Hf, Ta and Th. In detail, however, there are distinct differences in major and trace-element signatures, accessory mineral assemblages, facies distribution and provenance of the terrigenous precursor sediments. Enrichments in high field-strength elements and heavy rare earth elements are largely attributable to accumulation of heavy minerals like zircon in the precursor. Petrological and trace-element evidence does not support a direct genetic relationship between bauxite and the underlying saprolitic clays. The complex petrologic characteristics and compositional heterogeneity of the coastal-plain deposits can essentially be explained by element fractionation, primarily through selective leaching, in combination with relative and absolute enrichment processes, erosion and reworking during two-stage, polycyclic bauxitization of a heterogeneous precursor. 相似文献
18.
Standardization of metal concentrations in sediments using regression residuals: an example from a large lake in Florida, USA 总被引:6,自引:0,他引:6
A new method of standardizing metal concentrations in sediments was tested on samples from Lake Miccosukee, a large karstic
lake in north Florida. Metal concentrations were analyzed in 222 sediment samples from 26 cores representing 9 sampling sites
in the lake. Measured sedimentation rates in the lake are low. Percent organic matter strongly increases upward in all the
cores. The C/N ratio remains constant throughout all the samples, with a mean value of about 13, regardless of depth or location.
All of the geochemical variables are at least approximately log-normally distributed; thus, log-log or semi-log scattergrams
were used and the data were log-transformed before statistical calculations were performed. Some elements (Mn, Zn, Hg, Cu,
and Ca) are primarily associated with the organic fraction; others (La, Cr, Sr, and Ba) are clearly related to the terrigenous
fraction; others show affinities for both fractions. Consequently, no bivariate scattergrams or plots of ratio versus depth
– commonly used for standardization by plotting or ratioing a reference element (such as Al) to an element of interest – were
found to be adequate for standardization of this dataset. The best method for standardization was found to be one based on
multivariate (trivariate) linear regression, using log Al and log C as the independent variables (reference elements representing
terrigenous and organic fractions, respectively), and the log of the element of interest as the dependent variable. Residuals
(deviations) from the best-fit linear surface were then plotted versus depth in the cores to accomplish the standardization.
The results indicate that, with the possible exception of Mn at two sites, there is little evidence of anthropogenic input
of trace elements to the lake, and most trace-element concentrations in the lake can be considered as valuable baseline information.
A significant finding is that different and erroneous conclusions might have been reached if other standardization methods,
not based on trivariate regression, had been employed.
Received: 28 August 1997 · Accepted: 24 November 1997 相似文献
19.
《Chemie der Erde / Geochemistry》2015,75(2):219-236
The formation of iron sulphide minerals exerts significant control on the behaviour of trace elements in sediments. In this study, three short sediment cores, retrieved from the remote Antinioti lagoon (N. Kerkyra Island, NW Greece), are investigated concerning the solid phase composition, distribution, and partitioning of major (Al, Fe) and trace elements (Cd, Cu, Mn, Pb, and Zn). According to 210Pb, the sediments sampled correspond to depositions of the last 120 years. The high amounts of organic carbon (4.1–27.5%) result in the formation of Fe sulphides, predominantly pyrite, already at the surface sediment layers. Pyrite morphologies include monocrystals, polyframboids, and complex FeS–FeS2 aggregates. According to synchrotron-generated micro X-ray fluorescence and X-ray absorption near-edge structure spectra, authigenically formed, Mn-containing, Fe(III) oxyhydroxides (goethite type) co-exist with pyrite in the sediments studied. Microscopic techniques evidence the formation of galena, sphalerite and CuS, whereas sequential extractions show that carbonates are important hosts for Mn, Cd, and Zn. However, significant percentages of non-lattice held elements are bound to Fe/Mn oxyhydroxides that resist reductive dissolution (on average 60% of Pb, 46% of Cd, 43% of Zn and 9% of Cu). The partitioning pattern changes drastically in the deeper part of the core that is influenced by freshwater inputs. In these sediments, the post-depositional pyritization mechanism, illustrated by overgrowths of Fe monosulphides on pre-existing pyrite grains, results in relatively high degree of pyritization that reaches 49% for Cd, 66% for Cu, 32% for Zn and 7% for Pb. 相似文献
20.
Geochemistry of Cu, Co, Ni, Zn, Cd and Cr in the surficial sediments of a tropical estuary, southwest coast of India: a granulometric approach 总被引:3,自引:0,他引:3
Geochemical characteristics of six trace metals – Cu, Co, Ni, Zn, Cd and Cr – in the bulk sediment and sand, silt and clay
fractions of a tropical estuary on the southwest coast of India have been studied and discussed. In bulk sediment, the trace
metal concentration is controlled mainly by the textural composition of the sample. Mud, sandy mud and sandy silt register
higher concentrations of trace metals than that in sand-dominant sediments. The granulometric partitioning studies also re-affirmed
the role of particle size in enriching the trace metals. The silt and clay fractions exhibit 7–8 times the enrichment of Cu
and Cd compared to that in sand. The enrichment factors of Zn, Cr, Ni and Co in the silt and clay fractions, compared to that
in sand, are 5–6, 4–5, 2–5 and 2–3 times, respectively. The trace metals in the sand fraction, particularly Ni and Cr, exhibit
strong positive correlation with the heavy mineral content of the samples. It clearly indicates a heavy mineral pathway to
the trace metals in the sand fraction. Cu and Co in silt and clay fractions exhibit a marked decrease towards the high saline
zones of the estuary. This is attributed to the desorption of Cu and Co from particulate phases during estuarine mixing. Contrary
to Cu and Co, the content of Zn in the clay fraction shows a marginal increase towards the estuarine mouth. This could be
explained by the influx of Zn-rich contaminant discharges from Zn-smelting industries located slightly north of the estuarine
mouth. The released Zn will effectively be held in the lattices of the clay mineral montmorillonite, which also exhibits a
marked increase towards the estuarine mouth. The anomalously high values of Cd in some places of the Central Vembanad estuary
is attributed to the local pollution.
Received: 10 July 1995 · Accepted: 3 June 1996 相似文献