Distribution of metal concentrations in sediments of the coastal zone of the Gulf of Riga and open part of the Baltic Sea

The comparison of spatial and temporal distribution of Hg, Cd, Pb, Cu, Ni, Zn, Mn and Fe concentrations in sediments from the Gulf of Riga and open Baltic Sea along the coastal zone is presented for the first time. There were considerable differences in Pb, Zn, Mn and Fe levels in sediment at various stations of the Gulf of Riga. A significant difference of Cd, Pb, Cu, Ni, Zn levels was found in sediments of various stations in the open Baltic coast. The amount of Cd, Pb, Cu, Ni, Zn and Fe levels also differed significantly in the sediments of the Gulf of Riga in different years. A considerable yearly difference in amount of Hg, Cd, Pb, Cu, Ni and Mn levels was found in sediments in the open Baltic coast. The essential highest values of Pb and Zn in coastal sediments of the open Baltic Sea are stated in comparison with the Gulf of Riga. The concentrations of other metals have only a tendency to be higher in coastal sediments of the open Baltic Sea in comparison with the Gulf of Riga. Natural and anthropogenic factors were proved to play an important role in determining resultant metals concentrations in the regions.     

Metal sources to the Baltic clam Macoma balthica (Mollusca: Bivalvia) in the southern Baltic Sea (the Gulf of Gdansk)

Metal concentrations of Cu, Fe, Mn, Ni, Pb and Zn in an infaunal facultative deposit-feeding bivalve, the Baltic clam Macoma balthica, in the Gulf of Gdansk (southern Baltic Sea) were assessed and compared to selected concentrations of metals in the environment. Between October 1996 and September 1997, dissolved and easy extractable (by 1M HCl) metal fractions of total suspended particulate matter (TPM) in the overlying water and of surficial sediments (<63 microm) were measured monthly at five sublittoral sites in the Gulf of Gdansk, and accumulated tissue metal concentrations in M. balthica were determined simultaneously. The study highlights the importance of sediment geochemistry as a factor modifying ambient trace metal bioavailabilities. Surficial sediments appeared to contribute most to the accumulation of Cu and Pb in M. balthica, reflecting the high metal availability in the Gulf. Assimilation of Cu from sediments is controlled by Mn components possibly through an inhibitory effect of Mn oxyhydroxides, while Pb accumulation from sediments depends on the organic content of the sediment. A dual metal uptake pathway, with a suspended particulate-bound fraction and surficial sediments, was apparent for Mn and Zn. Partitioning of Mn in sediments was related to the concentration of labile Fe, with increased levels of Fe tending to inhibit the accumulation of Mn by the clam. Tissue accumulated Zn might have been altered by the clam's internal regulation, making Zn tissue concentrations, to some degree, independent of its environmental level. The principal source of Ni accumulated by the clams exists in the soluble phase.     

Tapes philippinarum seed exposure to metals in polluted areas of the Venice lagoon

The concentration changes of 12 metals (As, Hg, Cd, Cr, Co, Cu, Pb, Mn, Ni, V, Zn, Fe, and Hg) in the soft tissues of Tapes philippinarum during growth were investigated. Clams were seeded in two contaminated areas of the Venice lagoon (San Giuliano and Fusina) and in an area of the Marano lagoon (Lignano Sabbiadoro) close to the clam-farm where the seed was produced. Metal trends were very different according to the considered element, the study site and the growth period.Arsenic was always higher in clam tissues than in surface sediments and suspended particles in all the three stations. Mercury, Cd and Cu were higher in the clams from Marano and Fusina but not in those from San Giuliano. Zinc and Co in clams exceeded the concentrations in the sediment and suspended particles only at Marano. The other elements (Cr, Pb, Mn, Ni, and Fe) were always higher in SPM and sediments. In general metal concentrations in clams were more highly correlated to concentrations in the suspended particles rather than in the surface sediments and in suspended clams rather than in bottom clams, nevertheless significant differences between stations and contaminants were found. Metal concentrations in clams were always lower than the European regulatory limits.     

Heavy metals in sinking particles and bottom sediments from the eastern Turkish coast of the Black Sea

Concentrations of Cd, Cu, Cr, Co, Ni, Zn, Fe, Mn, Pb, As, and Sb were determined in sediment trap and bottom sediment samples collected seasonally from a station on the eastern Turkish coast of the Black Sea. Cd, Pb and Mn concentrations were highest in the sediment trap samples except during the summer period, whereas Co, Ni, Zn and Fe levels were much lower than corresponding levels found in the surface sediments. Cu, Cr, As and Sb levels showed no definite trend with sediment type. In general, with the exception of Cr, relatively lower metal concentrations in the sediment trap material were determined in the summer period. The highest mass flux, 56.5 g m⁻² day⁻¹, was measured during autumn. The highest flux of heavy metals also occurred during autumn and was strongly dependent on particle mass flux. Based on these results, we suggest that the downward vertical transport of particulate heavy metals in this region is related to the high degree of land erosion and the resultant particulate flux dynamics, which occur here. It was noteworthy that the highest concentrations of Cd, Cu, Co, Zn, Fe and Sb in particles were measured during winter a finding which suggests that enhanced fossil fuel combustion, which occurs during this period in adjacent urban and industrial areas plays an important role in the metal composition of sinking particles in nearshore waters.     

Behaviour of copper,zinc, iron and manganese during experimental resuspension and reoxidation of polluted anoxic sediments

Samples of anoxic intertidal sediments from the Mersey Estuary, north-west England, have been used in laboratory experiments to determine the rates and extents of metal (Cu, Zn, Fe, Mn) releases to solution under conditions of controlled resuspension and reoxidation. An experimental system for the study of sediment-water interactions at various temperatures, salinities, pHs and oxygen concentrations is described. The results indicate rapid initial losses of Fe and Mn from sediment but not Cu and Zn with longer term readsorption of Fe and Mn to give partitioning between the aqueous/ sediment phases for all four metals which is similar to that under the initial anoxic conditions. Cu and Zn show small, but measurable, net losses from the aqueous phase to the reoxidized sediment. Salinity variations exert little influence on the processes observed, but increasing temperature produces increased Cu, Zn and Mn in the dissolved fraction at equilibrium conditions. Exchanges of Cu and Zn between the sediment/water phases are rather insensitive to pH or oxygen concentration, but Fe and Mn do respond to increasing pH which suppresses their initial release on oxidation. Low oxygen concentrations can result in a slow but significant release of Fe. In relation to trace metal pollution in estuaries and biological availability, the results suggest that the resuspension and oxidation of polluted anoxic sediments is not an important process because of scavenging of soluble metals on to the resuspended material.     

The distribution and geochemistry of some trace metals in the Bermuda coastal environment

Results of the analyses of the water column and sediments of the Bermuda Platform for Cd, Cu, Fe, Mn, Ni, Pb and Zn are presented. The major process controlling the water column concentrations is physical mixing of open ocean waters with inshore waters, which are polluted by a wide range of diffuse inputs. Sedimentation within the inshore waters plays a lesser, but significant, role as do fluxes from the sediments of Fe and Mn and possibly phytoplankton uptake of Zn. Concentrations within the sediments are controlled by the formation of trace metal enriched clay/organic particles in the inshore areas and their subsequent redistribution by sediment resuspension, except for Fe and Mn which are largely associated with clay lattices.     

Variability of metal contents in the sea rush Juncus maritimus-estuarine sediment system through one year of plant's life

Metal accumulation by Juncus maritimus and the effect this plant might have on the physico-chemical composition of sediments, from Douro river estuary (NW Portugal), were investigated through one year of plant's life. The contents of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined (by atomic absorption spectrophotometry) in sediments, rhizosediments (those among plant roots and rhizomes) and different tissues of J. maritimus. Two estuarine sites with different characteristics were studied, one a sandy sediment with relatively low organic matter content, the other a muddy site. The role of the plant seemed to be markedly dependent on the sediment composition. At the sandy site, significant variations throughout the year (a decrease from winter to summer and an increase in autumn) either in rhizosediment and sediment or in J. maritimus roots were only observed in Cd and Cu levels. These variations were the same in both compartments, probably caused by tidal water movements and the activity of the plant. At the muddy site, variations throughout the year were observed for all studied elements but Pb. Changes in the Cd and Zn contents of roots were opposite to those in the rhizosediment (uptake of Cd and Zn by J. maritimus roots in summer may have caused a decrease in rhizosediment levels). Fe and Mn showed similar patterns of variation in both roots and rhizosediment (contents significantly increasing in summer). Higher contents of Fe and Mn in roots in summer could be related to changes in mass, higher availability of the elements, or accumulation at the surface of the root in (hydr)oxides forms. For the remaining elements no significant correlations between rhizosediment and roots variations were observed, indicating that their uptake and release by roots were not based on single exchanges with the sediment. J. maritimus showed capacity to accumulate Cu, Zn and particularly Cd, thus appearing to be useful for the phytostabilization of these metals.     

上海滨岸潮滩根际重金属含量季节变化及形态分布

用Zeeman－5000型原子吸收分光光度计火焰法测定了上海滨岸潮滩沉积物中Cu、Pb、Fe、Mn、Zn、Cr的总量及其5种地球化学形态含量，发现根际沉积物中的重金属含量一般低于表层沉积物，但在重金属含量水平上，均为Fe＞＞Mn＞Zn＞Cu，Pb，Cr；单因子方差分析表明重金属在根限沉积物中存在显著的季节变化（p＜0.05＝，Cu、Pb、Fe、Mn、Zn、Cr在高潮滩芦苇根限沉积物中的含量均在夏、秋季出现最低值或次低值，在中潮滩海三棱Biao草根际沉积物中的季节含量随采样地点不同而变化，但与同一地点表层沉积物中的含量相关性很好，除Cr（r＝0．18）外，相关系数（r）分别达到0．77、0．74、0．65、0．84、0．77；Cu、Fe、Zn、Cr在沉积物中均以残渣态含量为主，Pb、Mn的碳酸盐结合态含量较高，秋季各重金属元素的碳酸盐结合态与铁锰氧化物结合态之间发生形态上的迁移与转化。     

Extreme variation in the concentration of trace metals in sediments and bivalves from the Bilbao estuary (Spain) caused by the 1989-90 drought

Intertidal sediments and bivalves Scrobicularia plana from Bilbao estuary (Spain) were repeatedly sampled during and after the 1989-90 drought. The organic content (OC) and the concentration of most of the 10 metals analysed in sediments were extremely variable (e.g. Cd ranged from 4 to 112 micrograms g-1, ppm dry wt), and they were strongly related to an index applied to estimate the magnitude of the drought (namely the deficit flow of the main river). After OC normalisation, the correlation versus deficit was lost for some elements (Cr, Fe, Ni) but not for others (Cd, Co, Cu, Pb, Zn). This leads to the conclusion that both a natural and a man-induced process account for the observed rise and fall of the contamination pattern: the reduced river flow raised the metal-binding capacity of sediments, and restrictions in the water supply increased the corrosion of sewers and their leaching of some elements. The concentration of trace metals in local bivalves (Cd reached 100 and 458 ppm dry wt, respectively, for whole tissues and digestive gland) mirrored the sediment contamination dynamics, but at a slower pace. The means by which S. plana is able to tolerate such high Cd tissue levels remain unknown. These results constitute some prime field evidence of drought effects that should be born in mind when pollution and risk from climate change are assessed in estuaries.     

Assessment of elemental contamination in estuarine and coastal environments based on geochemical and statistical modeling of sediments

Sediment of variable mineralogical, textural and metal contaminant composition was collected from 38 estuaries along the Atlantic and Gulf of Mexico coasts of the United States and analyzed for total Al, Ag, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Si, Sn, Tl and Zn concentrations. Based on observed covariation of elements at 15 estuaries remote from contaminant inputs, linear regressions of metals on Al were used to model the metal content in baseline sediments. A geochemical model for the covariation was developed, verified and used to guide the statistical modelling approach. Comparison of metal concentrations predicted by the models with those occurring in uncontaminated geological materials suggests that baseline relationships are valid for the entire region sampled. Using these baseline relationships, sediment metal concentrations can be partitioned into natural and anthropogenic fractions. Models improve the comparability of metal levels in sediments by correcting for variable background concentrations that, if left uncorrected, only serve to increase total data variability and reduce detection of spatial and temporal differences.Examples of the application of baseline models to pollution studies are provided. A continuing decline in Pb concentrations in Mississippi River delta sediments is observed consistent with the declining use of Pb additives in gasoline since 1970. Major spatial trends in contaminant metals in sediments along the Atlantic and Gulf of Mexico coasts are noted.     

Distribution of trace and major elements in sediment and pore waters of the Lena Delta and Laptev Sea

Sediment cores collected during the SPASIBA expedition in 1991 were analysed for their trace- and major element concentrations. Leachable (0.1 N HCl) as well as residual concentrations were determined. Fe and Mn were measured in the interstitial waters to characterize redox conditions. Lateral distribution patterns of solid phase Cu, Cd, Ni, Pb and Zn show a small increase in concentration from the Lena Delta in seaward direction. In general concentrations of these metals are very low and similar to natural background values. With some exceptions, solid phase profiles with depth of all investigated elements do not show strong variations. No enrichment of Pb and Zn in surface layers was found. Remobilization processes and transport of particles enriched in Mn are responsible for Mn accumulation in a particular area. Pore-water concentrations of dissolved Mn in the latter sediments are very high (> 700 μM) and suggest strong Mn reduction directly below the sediment-water interface. In contrast to Mn, the depth profiles of Cd show a surface layer with lower concentrations and an increase deeper down the sediment. The C/N ratio in the sediment decreases from 13 in the Lena mouth to 9 in the more marine part of the Laptev Sea. Surface sediments in the Laptev Sea are very uniform and homogeneous and show only small concentration gradients.     

A statistical study of environmental factors controlling concentrations of heavy metals in the burrowing bivalve Scrobicularia plana and the polychaete Nereis diversicolor

Multiple regression analyses indicate that the most important factors controlling Ag, Cd, Co, Cu, Pb and Zn concentrations in the estuarine bivalve Scrobicularia plana and the polychaete Nereis diversicolor are the concentrations of these metals in surface sediments and the partitioning of sediment-bound metals between different sediment constituents. Extraction of the sediments with 1-n HCl provides more information about the bioavailability of the metals than do extractions with five other techniques. Biologically available Cd and Co in solution contribute significantly to Cd and Co concentrations in both Scrobicularia and Nereis. Concentrations of Ag in Scrobicularia are reduced where Cu concentrations in sediments are high. An unexplained increase in concentrations of Cu in Scrobicularia at specific stations in six estuaries suggests that under certain very anoxic conditions the availability of copper may be exceptionally high.     

粤西湛江港海底沉积物重金属的分布特征与来源

2004年9月23日至10月5日对湛江港海洋沉积物中金属元素的含量及分布进行了调查。共采集样品20个,采用王水-氢氟酸消解,电感耦合等离子体发射光谱法测定样品中的金属元素As、Cd、Co、Cr、Cu、Ni、Pb、Zn、Al、Ca、Fe、Mg和Mn。结果发现,湛江港大多数区域的沉积物未受污染,但霞山区港务局码头附近海域受到Cd、Cu和Pb的轻度污染,特呈岛养殖区也受到Cu的轻度污染。主成分分析结果表明,Al、Cd、Co、Cr、Cu、Fe、Ni、Pb和Zn主要通过陆源输入进入近岸水域的沉积相中,Ca、As、Mg和Mn主要通过海洋环境中水相和沉积相的相互作用进入沉积相中。结合其它调查结果认为,湛江港的Cd污染在水相、沉积相和生物相中均已存在,应引起有关部门的高度重视。     

Environmental status of Daya Bay surface sediments inferred from a sequential extraction technique

The chemical partitioning of 12 trace metals (Ba, Cd, Co, Cu, Mn, Mo, Ni, Pb, Sc, Sr, U, Zn) in 9 surface sediments from Daya Bay, northern South China Sea, was studied by a four-step sequential extraction technique to assess their environmental/pollution status. The studied metals take on different fraction composition patterns, and some of them show significant spatial variation especially for Cd. A majority of the studied metals can be considered immobile because of their high percentages in the residual fraction. It seems that the Daya Bay surface sediments have not yet been polluted by the studied heavy metals which are used as parameters to classify marine sediment quality, i.e., Cd, Cu, Ni, Pb and Zn. For all metals except for Pb, the extent of anthropogenic influences on their total concentrations in the Daya Bay surface sediments is generally imperceptible. The metals’ potential risks to the environment were assessed, and the results showed that they have generally no risk or low risk except for Cd, Mn and Sr.     

海水养殖池沉积物中重金属形态和生物酶活性的关系研究

以连云港市对虾养殖池表层沉积物为研究对象,采用Tessier连续萃取法,研究了表层沉积物中重金属(Cu、Zn、Pb、Cd、Cr、As、Mn)的赋存形态和酶(脲酶、碱性磷酸酶、过氧化氢酶、转化酶)活性的相关性。结果表明,重金属Cu和Zn以有机-硫化物结合态为主要的赋存形态,Pb以铁锰氧化物态为主要的赋存形态,Cd以可交换态(平均33.47%)和碳酸盐结合态(平均31.16%)为主要存在形态,Cr和As主要以残渣态存在,Mn的铁锰氧化物态比例最高。脲酶的活性范围为0.45—8.96mg/(g·24h),碱性磷酸酶活性范围为2.45—6.69mg/(g·24h),过氧化氢酶活性范围为0.14—2.36m L/(g·min),转化酶活性范围为0.45—10.45mg/(g·24h)。脲酶活性与Cd、As的可交换态、Cd的碳酸盐结合态、Cu、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫化物态之间显著相关;碱性磷酸酶活性与Zn、Cd的铁锰氧化物态显著相关;过氧化氢酶活性与Cd的可交换态、碳酸盐结合态及残渣态、Cu、Cd、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫结合态之间显著相关;转化酶活性与Cu、Cd、As的可交换态、Cd的碳酸盐结合态、Cu、Cd、As的铁锰氧化物态、Zn、Pb、Cd、Mn的有机硫化物态、Cd、As的残渣态之间显著相关。酶活性可以用来指示海水养殖池沉积物中重金属的形态转化过程。     

The spatial and seasonal variation of trace metals in coastal seawater and soft tissue of <Emphasis Type="Italic">Chthamalus montagui</Emphasis> around the northwest coast of Portugal

Metal concentrations (Cd, Cr, Cu, Fe, Mn and Zn) were determined in seawaters and soft tissues of Chthamalus montagui from the northwest coast of Portugal during the four seasons of 2011. The main objectives of this work were to assess seasonal and spatial variations of metals in order to detect hot spots of contamination, to establish correlations between metals in coastal seawaters and C. montagui and to calculate metal bioaccumulation factors (BAFs) in each season. Metal concentrations in coastal seawaters ranged within Cd: 1.2–35 ng L^?1; Cr: 15–87 ng L^?1; Mn: 77–1763 ng L^?1; Cu: 126–1819 ng L^?1; Fe: 430–4048 ng L^?1 and Zn: 2889–16867 ng L^?1 and in C. montagui ranged for Cd: 0.39–1.98 mg kg^?1; Cr: 0.45–3.13 mg kg^?1; Cu: 0.93–5.70 mg kg^?1; Mn: 2.2–20.4 mg kg^?1; Fe: 135–707 mg kg^?1 and Zn: 119–782 mg kg^?1. Significant spatial and seasonal variations were found between: (i) metal concentrations in seawaters and C. montagui tissues; (ii) the distribution of metal concentrations in C. montagui tissues were Fe > Zn > Mn > Cu > Cr > Cd and (iii) C. montagui showed higher bioaccumulation factors for Fe and Cd than for Cu, Mn and Zn in all seasons. Regarding the metal concentrations accumulated in C. montagui tissues during each season of 2011, the ecological quality classifications of the NW coast of Portugal varied from “Class I–Unpolluted” to “Class III–Remarkably Polluted”.     

Distribution and Enrichment of Heavy Metals in Recent Sediments of Safaga Bay,Egypt

The present study was undertaken for assessing the level of heavy metals such as iron, manganese, zinc, copper, nickel, cadmium, lead, and cobalt in recent sediment samples of Safaga Bay, Egypt. Concentration of heavy metals in sediments shows significant variability and ranges from 863.37 to 1144.93 ppm for Fe, 64.29–586.8 ppm for Mn, 2.7–12.68 ppm for Zn, 3.01–7.2 ppm for Pb, 1.53–3.29 ppm for Ni, 0.55–1.57 ppm for Co, 0.16–1.37 ppm for Cu, and 0.22–0.4 ppm for Cd.

Sediment pollution assessments were carried out using an enrichment factor and geoaccumulation index. The calculation of enrichment factor showed that Cd is enriched by 4.1 due to phosphate sources in Safaga Bay. The Geoaccumulation index results revealed that there are positive and negative correlations between Fe, Zn, Mn, Pb, Ni, Cu, Co, and Cd indicating that these metals have complicated geochemical behaviors.     

Vertical distribution of the macrobenthic community and its relationships to trace metals and natural sediment characteristics in the lower Douro estuary, Portugal

Vertical distribution (0–15 cm) of the macrobenthic community and its relationships to natural sediment characteristics and trace metal contents and bioavailability were studied at five locations in the lower Douro estuary, Portugal. An analysis of vertical metal distribution, for the interpretation of anthropogenic impact on the estuarine sediments, was also investigated. Sediment characterisation included organic matter, grain size, metals (Al, Fe, Cu, Pb, Cr, Ni, Cd, Zn and Mn), acid volatile sulphide (AVS) and simultaneously extracted metals (SEM). The macrobenthic community had low diversity (14 species), was dominated by small size opportunists and seemed to be controlled mainly by natural factors such as grain size distribution, Al and Fe contents and sediment depth. The vertically heterogeneous distribution of macrobenthic community appears to affect redox status of the sediments and consequently metal bioavailability. Despite anthropogenic contamination in terms of Zn, Cu, Pb, Cr and Ni having already been detected in the north bank, the analysis of vertical distribution was essential for the identification of current anthropogenic contamination in terms of Zn, Pb and Cd in the south bank.     

Some peculiarities of the trace-metal distribution in Baltic waters and sediments

Between 1980 and 1984 extensive studies were carried out in the Baltic Sea on trace metals (Cd, Co, Cu, Fe, Hg, Mn, Ni, Pb and Zn) in water, suspended matter and sediments. The results enabled the influence of different factors on metal distribution patterns to be considered. The vertical profiles of dissolved and particulate metals in waters of the central deep basins reflect influences caused by oxygen deficiency and anoxic conditions in near-bottom water layers. Peculiarities at Station BY15 in the Gotland Deep included high dissolved Fe, Mn and Co concentrations and remarkable enrichment of Zn (0.64%), Cd (51 μg g⁻¹) and Cu (0.15%) in particulate matter from the anoxic zone. Manganese-rich particles were accumulated above this layer.In fine-grained soft sediments below anoxic deep waters, maximum contents of Cd, Cu and Zn were observed, relative to other coring sites, between Bothnian Bay and Lübeck Bight. The Hg content in sediments probably reflects the joint flocculation with organic matter. Land-based sources seem to play the leading part for maximum lead contents.     

Heavy metals in surface sediments of Waiwhetu Stream,Lower Hutt,New Zealand

Abstract

Surface sediment samples (60 μm‐2 mm, and < 60 μm fractions) from the Waiwhetu Stream, Lower Hutt City, New Zealand, were leached with dilute HCl to remove the mobile heavy‐metal fraction. Cd, Cr, Cu, Pb, Zn, Al, Fe, and Mn analyses of the leachates show that sediments of the upper reaches area of the stream are generally uncontaminated. In contrast, sediments in the lower reaches area are highly contaminated, despite clean‐up measures in the late 1970s. Lead and Zn are the most significantly enriched metals with concentrations over 1000 mg kg^?1 adjacent to some drains. In the polluted zone, metals originate from either upward remobilisation from underlying sediment (contaminated in the early 1960s and 70s) or more recent industrial spillages. Similar trends exhibited by Cd, Cu, Cr, Zn, Pb, and Al indicate that a proportion of the metal enrichment downstream probably results from a naturally higher clay content of sediments near the mouth of the stream. Fe and Mn show reverse trends to the other metals, indicating that a high proportion of these two metals occurs in substrate different to that of the other metals. The orange brick‐coloured sediments of the upper reaches of the stream indicate oxides upstream; the black sediments in the lower reaches indicate sulphides downstream.