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1.
Surface sediment samples in the Laptev Sea have average 137Cs content of 7.1 Bq kg(-1), a value intermediate between that of the western Kara Sea (23 Bq kg(-1) and the East Siberian Sea (4.2 Bq kg-'). Both surface sediment content and sediment inventory of 137Cs in the Laptev Sea sediments show significant variability, and the influence of a variety of environmental factors.137Cs concentrations in the Laptev Sea surface sediments range from 0.8 to 16 Bq kg(-1). There is a marked increase in 137Cs content of surface sediment samples collected near the Lena River delta, and a local enrichment in the 137Cs inventories at these sites is also evident. Fine-grained mixed-layer illite/ smectite rich sediments in the estuary provide effective adsorption sites to fix 137Cs, in spite of desorption processes associated with low salinities in estuarine mixing. The Lena River-Laptev Sea mixing zone is a major site of sea-ice production. River and shelf sediments are incorporated into sea-ice formed in this region (Holmes and Creager, 1974). The irregular 137Cs activity profiles of the Lena River estuary cores indicate disturbance or removal of 137Cs-laden sediments via sea-ice related processes. Lena River and Estuary sediments may have served as a secondary source (i.e. other than direct fallout) of 137Cs in sea-ice. North-east of the Lena River estuary, sediment contains a thin layer of 137Cs-bearing material over an erosion surface. The 137Cs-laden surface layer may be the result of transient deposition of estuarine sediments being delivered by sea-ice or spring floods. 相似文献
2.
Izmir Bay is one of the great natural bays of the Mediterranean. The surface sediment and fish samples were collected during 1997-2009. The sediment concentrations of inner bay showed significant enrichments during sampling periods. Outer and middle bays exhibited low levels of metal enrichments except the estuary of Gediz River. The concentrations were generally higher than the background levels from the Mediterranean and Aegean except Cd and Pb levels gradually decreased. Metal EF is used as an index to evaluate anthropogenic influences of metals in sediments. Maximum metal enrichment was found for Hg in the outer bay, while Pb indicated maximum enrichment in the middle-inner bays. Metal levels were evaluated in sediments in accordance with the numerical SQG of the USEPA. The levels of fish tissues were lower than the results reported from polluted areas of the Mediterranean. The highest BAFs were detected for Hg and Cd in fish. 相似文献
3.
5beta-Coprostanol together with eight other sterols and unresolved complex mixtures (UCMs) were quantitatively investigated for surficial sediments and surface waters to assess the impacts of anthropogenic activities on the Pearl River estuarine and marine environment of South China Sea. The studied area extends from the Pearl River Estuary southward to the open sea. 5beta-Coprostanol concentrations ranged from trace amounts to 53 microgg(-1) TOC in surficial sediments. The highest levels and highest percentages of coprostanol were found in the Pearl River estuary, especially in the inner estuary and those sites close to the submarine outfalls of Hong Kong. For waters, only in estuarine samples was coprostanol quantitatively detected, ranging from 11 to 299 ngL(-1). Bimodal UCM "humps" were observed for most sediment samples, with concentrations ranging from 215 to 10,491 microg g(-1) TOC in sediments and from 2 to 26 mcirogL(-1) in waters, respectively. Progressive seaward declines in concentrations were found for both 5beta-coprostanol and UCM in surficial sediments. Trace or no 5beta-coprostanol was found in open-sea samples. Concentrations of coprostanol and UCM in surficial sediments are correlated. These results imply that there are obvious anthropogenic contaminations in the Pearl River estuary. The submarine outfalls in Hong Kong represent important sources of the sewage pollution to the Pearl River estuarine sediments evidenced by a combination of coprostanol concentration, diagnostic indices, sterol profiles and UCM. No obvious dispersion or transport of the sewage contamination occurred from the Pearl River estuary to the open South China Sea indicated by fecal sterol biomarkers. 相似文献
4.
P. W. French 《Marine pollution bulletin》1993,26(12):692-697
A series of 150 samples from the contemporary intertidal zone of the Severn Estuary and Bristol Channel have been analysed for levels of copper, lead, zinc, rubidium, and particulate coal debris to investigate the present pollution status of the system. The analysis reveals a systematic streamwise variation in pollution concentrations which is taken to reflect a combination of land-based pollutant inputs and the reworking of pollutant-rich sediments from the erosion of salt marshes along the margins of the estuary.
This streamwise variation demonstrates a down-stream decrease in concentration, superimposed on which are nine areas of contemporary pollutant input with regard to metals but non relating to coal. The occurrence of coal in modern intertidal sediments at levels significantly higher than the underlying pollution trend is only possible via the reworking of anthropogenically derived material stored in the intertidal sediments of the system and from a wreck located offshore. 相似文献
5.
Influence of the Aznalcóllar mining spill on the vertical distribution of heavy metals in sediments from the Guadalquivir estuary (SW Spain) 总被引：2，自引：0，他引：2
The Natural Park of Do?ana and the Guadalquivir estuary were impacted by the release of 6 million cubic meters of acid waste after the mine-tailing spill in Aznalcóllar (Andalusia, SW, Spain). Here is presented the monitoring of the accidental spill on vertical distribution of heavy metals in the estuarine sediments. The total concentration of six metals (Fe, Mn, Zn, Cd, Pb, Cu), their chemical speciation and the organic carbon concentration were analyzed in sediment vertical profiles. The results obtained determine background levels similar to previously reported in the area. The analysis catalogues the impact of the accident on the estuary as acute and mainly associated with high concentrations of Zn and Cd. The recent enrichment in Zn and Cd and their geochemical association with the more mobile fractions of the sediment determine an environmental risk associated with the acute impact and detected in some of the areas of the estuary. 相似文献
6.
C.L Macleod M.D Scrimshaw R.H.C Emmerson Y.-H Chang J.N Lester 《Marine pollution bulletin》1999,38(12):1870-1125
Salt marshes have recently been considered to be a major part of the coastal system and have played a key role in the development of the UK coastal management strategy. Managed Retreat (MR) is a process aimed to restore salt marshes by realignment of the seawalls allowing tidal inundation of low value agricultural land. The resultant marshes are expected to function both as an integral part of the flood defence system and as an ecological conservation area. We report on the effects of salt marsh restoration on metal and nutrient loading of the sediment at the Orplands Farm MR site, Essex, UK. Surficial grab and sediment cores were collected from the two fields that comprise the site. The heavy metals, Cd, Cr, Cu, Hg, Pb, Ni and Zn were analysed to determine changes in anthropogenic inputs to sediments. The major ions, Al, Ca, Fe, K, Mg, Mn and Na were also monitored to identify changes in sediment geochemistry. Analysis of the cored sediments after inundation for Na and Sr demonstrated that penetration of estuarine water had, within 2 yr of exposure, reached an average depth of 20 cm. The study observed that input of heavy metals had occurred to the sediments with the most significant being that of Pb, however increases were also observed for Cr and Cu. However, concentrations of Cd in the MR sediments decreased from 1995 to 1997. For the major metals within both fields it was found that the dominant changes were those of enrichment of marine associated metals, Ca, K, Mg and Na via inputs from tidal inundation. The concentration of Ca in the sediments was further enriched by the deposition of carbonates to the sediments. One field demonstrated a significant loss of Fe from sediments which corresponded to changes in redox potential of the sediments. Differences observed in geochemical profiles between the two fields of the site were attributed to differences in land use prior to flooding. 相似文献
7.
Cearreta A Irabien MJ Leorri E Yusta I Quintanilla A Zabaleta A 《Marine pollution bulletin》2002,44(6):487-503
The distribution and abundance of benthic foraminifera and a range of elements have been analysed in six long cores (up to 10 m long) from the Bilbao estuary, N. Spain, to document environmental transformation of this estuarine ecosystem and to determine sediment contamination levels. Three different environmental zones could be distinguished in the recent sedimentary record based on its microfaunal and geochemical contents. Initially, a pre-industrial zone containing very abundant and diverse foraminiferal assemblages together with baseline metal levels. Secondly, an older industrial zone exhibiting co-existence of abundant and diverse foraminiferal assemblages with high concentrations of metals. Finally, a younger industrial zone with extreme concentrations of metals and barren of indigenous foraminifera. This environmental transformation has been caused by the discharge of untreated domestic and industrial effluents during the last 150 years. The occurrence of foraminifera in the two industrial zones and along the estuary is not related to defined levels of metals, and this seems to confirm oxygen limitation as the key factor to explain complete estuarine defaunation during deposition of the younger industrial zone (period 1950-2000). Effectiveness of current regeneration schemes could be assessed using microfaunal and geochemical proxies as environmental quality indicators. 相似文献
8.
Garcia-Orellana J Cañas L Masqué P Obrador B Olid C Pretus J 《Marine pollution bulletin》2011,62(8):1632-1640
In this work we discuss the historical record of metals as derived from a sediment core from the Port of Maó (Minorca, Spain), the second natural largest harbour in Europe. The sedimentation rate derived from radionuclide profiles increased by a factor of five since the 1960s due to the urbanisation of the town waterfront. Metal concentrations showed two different trends: (i) Pb and Sn inputs started during the second half of the 19th century and remained relatively high until mid-20th century; and (ii) Ag, Cd, Ni, Zn, Cu and Cr accumulation began in the 1940s, peaking in the late 1970s. The commissioning of a submarine outfall in 1978 reduced metal concentrations in subsequently deposited sediments since, thereafter, urban and industrial wastes have been dumped out of the estuary. This study also shows that evaluating the quality of sediments on the basis of surface concentrations may be misleading. 相似文献
9.
云南属都湖沉积物金属元素地球化学 总被引：2，自引：0，他引：2
通过对属都湖短岩芯Esdrl重金属元素的分析,结合沉积物粒度、流域降水和人类活动资料,讨论属都湖沉积物金属元素地球化学变化特征.结果表明.沉积物中AI、Mg、Co、Zn、Cr、Ti、V、Cu、Ni等元素含量变化与粘土含量、夏季降水量显著相关,降水导致的流域侵蚀强弱变化是影响元素含量变化的主要因素.元素Pb含量从岩芯底部到顶部总体呈上升趋势,25-17.5cm沉积物中Pb含量较稳定主要为自然侵蚀过程控制;17.5-10.5cm沉积物中Pb含量迅速增加后逐渐降低推测为20世纪50年代湖区附近矿山开采产生的粉尘沉降的影响;10.5-Ocm Pb含量逐渐增加,80年代以后大气中Pb含量上升.Pb在漉域的干湿沉降应是岩芯上部Pb含量升高的原因.在氧化还原作用下沉积物中Fe、Mn易在沉积物一水界面发生再迁移.25-7.5cm沉积物中的Fe、Mn含量变化特征为沉积后再迁移作用的结果;7.5-0cm Fe和bin含量明显上升,夏季降水量增加导致流域侵蚀增强和土壤的潜育化可能是岩芯上部Fe、Mn含量显著上升的原因. 相似文献
10.
Platinum contamination in estuarine and coastal sediments has been evaluated in three cores collected from the Tagus Estuary and Prodelta shelf sediments. Elevated concentrations, up to 25-fold enrichment compared to background values, were found in the upper layers of the estuarine sediments. The degree of Pt enrichment in the estuarine sediments varied depending on the proximity to vehicular traffic sources, with a maximum concentration of 9.5 ng g−1. A considerable decrease of Pt concentrations with depth indicated the absence of significant contamination before the introduction of catalytic converters in automobiles. Platinum distribution in the Tagus Prodelta shelf sediment core showed no surface enrichment; instead a sub-surface maximum at the base of the mixed layer suggested the possibility of post-depositional mobility, thereby blurring the traffic-borne contamination signature in coastal sediments. 相似文献
11.
Spatial distribution and source apportionment of PAHs in surficial sediments of the Yangtze Estuary, China 总被引：3，自引：0，他引：3
Spatial distribution and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments of the Yangtze Estuary, especially the North Branch, have been fully investigated. PAH concentrations increased with the descending distance from the inner estuary to the adjacent sea, and varied significantly in various estuarine regions. Water currents (e.g., river runoff and ocean current) greatly affected the distribution pattern. In addition, ambient sewage and traffic also contributed to the PAH pollution in the estuary. In the adjacent sea, PAH values along the -20m isobath were higher than those along the -10m isobath due to the "marginal filter" phenomenon formed by different water currents. In most sites, PAHs had poor correlations with sediment size, but had positive correlations with total organic carbon. Based on the qualitative and quantitative analysis results, PAH sources were proved to be mainly from a mixture of petroleum combustion, biomass, and coal combustion. 相似文献
12.
Evaluation of metal contamination in coastal sediments of the Bay of Bengal, India: geochemical and statistical approaches 总被引：11，自引：0，他引：11
Surface sediment samples collected from the inner shelf region of the Bay of Bengal, were analysed for the major elements and total and acetic acid available trace elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Si, Zn) to evaluate geochemical processes influencing their distribution. Major elemental analysis showed that the sediments had high concentrations of Si and relatively low concentrations of Al and Fe. Both major elemental and trace metal concentrations indicated that the sediments represent weathered products of granite and charnockite. Normalization of metals to Al indicated relatively high enrichment factors for Pb, Cd, Zn and Cr. The higher proportions of nondetrital Pb (66%), Cd (41%) and Co (28%) reveal metal contamination due to anthropogenic inputs. Factor analysis (FA) identified six possible types of sedimentological and geochemical associations. The dominant factor accounting for 26.9% of the total variance identifies an anthropogenic input and accumulation of nondetrital Cd, Co, Cr, Ni and Pb. Association of these metals with CaCO3 reveals that shell fragments in the surface sediments are likely act as a carrier phase for nondetrital metals. The results are discussed in the context of the sources and pathways of elements in the Bay of Bengal. 相似文献
13.
The concentration of selected trace metals (Cu, Pb and Zn) in salt-marsh sediments from within the Erme Estuary have been measured in order to assess possible historical sources of pollution. The Erme Estuary, south Devon, UK is an Area of Outstanding Natural Beauty and has remained largely unaffected by industrialisation, although a number of small silver–lead mines were in operation in the 1800s. Five cores reveal comparable geochemical profiles. An increase of lead at 40 cm depth is observed, reaching maximum values of 427 ppm. Less distinct trends are revealed by zinc and copper, probably reflecting the lack of widespread mining for ores of these elements within the catchment and possible post-depositional mobility rendering the metal concentrations non-contemporaneous with the chemostratigraphy of lead. The geochemical analysis of the salt-marsh sediments provides a fairly robust chemostratigraphic scheme and the likely sources of mine waste can be pinpointed within the catchment. Based upon reference to the historical mining record of these mines chemostratigraphic dating of the sediments can be achieved in order to provide an estimate of salt-marsh accretion rates and sea-level rise. 相似文献
14.
Concentration and fractionation of trace metals in surface sediments of intertidal Bohai Bay, China 总被引：4，自引：0，他引：4
Surface sediments from intertidal Bohai Bay were sampled for the geochemical and environmental assessment of six trace metals (Cd, Cr, Cu, Ni, Pb and Zn). Results indicate that sediment grain size plays an important role in controlling the distribution and fractionation of them. Metal concentrations in clayey silt sediments are all clearly higher than in sand and silty sand ones. Cd and Pb in clayey silt sediments are more mobile than in sand and silty sand ones. Two sediment quality guidelines and two geochemical normalization methods (index of geoaccumulation and enrichment factor) were used to judge the potential risk and accumulation of metals. According to the mean probable effects level quotient, the combination of studied metals may have a 21% probability of being toxic. The sediments with high fraction of clay and silt have been contaminated by trace metals to various degrees, among which Cr contributes the most to contamination. 相似文献
15.
The geochemical baselines and distribution of 31 elements (Al, Fe, K, Na, Mg, Ca, Mn, Ba, Cr, Zr, Ni, Sr, Zn, Y, Li, Cu, Mo, Nb, Th, Co, Ga, W, Ta, Be, Ti, Ge, Se, Bi, Te, Sc and Re) and physico-chemical parameters of the tropical surface sediments of the Terengganu River basin, Malaysia, are reported. Sediments are sandy loam to sand in texture consisting of mostly quartz, low organic matter content (average-2.68%), low CEC (average-2.02 cmol(+)/kg) and mildly acidic pH1:5 (average-5.91). Concentrations of Mn, Fe, Ba, Cr, Ni, Cu, Mo and Se were measured to be above the environmental sediment quality criteria at various locations. Lake sediments registered significantly higher Al, Fe, Ti, Mg, Ca, Mn, Te and Sc concentrations as compared to the river sediments. Most of the elements investigated showed an association with silt size fraction (2-63 μm). Among the investigated metals, Mo and Fe concentrations showed an increasing (5-fold) and decreasing (3-fold) trend, respectively, along the river path from the upstream to the downstream depending on the stream pH-redox conditions. The enrichment factor values (EF 5) of Cr, Ni, Mo and Se indicated enrichment from anthropogenic activities. Alkali and alkali earth metals registered a significant depletion (EF values 0.7) as compared to the Earth's crust. Principal component analysis of the two main components (PC1, 87.4% and PC2, 8.7%) revealed a well-defined group of estuary sediments. Lake and river sediment sampling locations did not form defined groups revealing heterogeneity in the origin of geologic material and the in-stream geochemical processes. However, Cr, Ni, Mo and Se formed a separate group with elevated concentrations (e.g. Cr1,000 mg/kg) indicating contamination of sediments. This work presents the geochemical baselines of the tropical sediments as industrial development and urbanization along the north east coast of Peninsular Malaysia are advancing rapidly. 相似文献
16.
Polycyclic aromatic hydrocarbons in the sediments of the Yalujiang Estuary,North China 总被引：22，自引：0，他引：22
Selected polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Yalujiang Estuary, North China, have been investigated by gas chromatography-mass spectrometry (GC-MS) for flood season (August, 1994) and dry season (May, 1996), respectively. PAHs concentrations from sediments range from 68 to 1500 ngg(-1) depending upon the sample locations. The most contaminated sediment samples are found in the turbidity maximum area for both dry and flood seasons. The source of PAHs is most likely pyrolytic, with minor contributions from petrogenic and diagenetic PAHs for some samples. Perylene is mainly derived from biogenic inputs, and occurs at almost stations. In the Yalujiang Estuary, both biogenic and anthropogenic hydrocarbons are primarily derived form riverine discharges and are accumulated in the mixing zone. The overall levels of PAHs in this study are low compared to other regions and reveal moderate PAHs pollution in the Yalujiang Estuary. 相似文献
17.
Gerald Maier Gillian A. Glegg Alan D. Tappin Paul J. Worsfold 《Marine pollution bulletin》2009,58(7):1007-288
Using the Taw Estuary as an example, data routinely collected by the Environment Agency for England and Wales over the period 1990-2004 were interrogated to identify the drivers of excessive algal growth. The estuary was highly productive with chlorophyll concentrations regularly exceeding 100 μg L−1, mostly during periods of low freshwater input from the River Taw when estuarine water residence times were longest. However, algal growth in mid estuary was often inhibited by ammonia inputs from the adjacent sewage treatment works. The reported approach demonstrates the value of applying conventional statistical analyses in a structured way to existing monitoring data and is recommended as a useful tool for the rapid assessment of eutrophication. However, future estuarine monitoring should include the collection of dissolved organic nutrient data and targeted high temporal resolution data because the drivers of eutrophication are complex and often very specific to a particular estuary. 相似文献
18.
Mercury concentrations in surface intertidal sediments from estuarine and coastal environments of the Northeastern Irish Sea are reported. This region has two inputs of mercury contaminated effluents from chlor-alkali factories, and localized mercury contamination of sediments fairly similar to that reported for the Rhine has been found in the Wyre estuary. The present results for the Mersey estuary agree well with others reported in the lierature. Coastal sediments are much less contaminated than the estuarine deposits, and in all the environments studied strong correlations between mercury concentration, total organic carbon and < 63 μm grainsize fraction contents have been found. 相似文献
19.
Role of living environments in the accumulation characteristics of heavy metals in fishes and crabs in the Yangtze River Estuary, China 总被引：1，自引：0，他引：1
Correlation of heavy metals in the tissues of typical organisms (i.e., fishes and crabs) and those in their living environments (i.e., surface water, bottom water, and sediment) in Yangtze River Estuary has been qualitatively and quantitatively analyzed. Metal levels followed the trend: sediments > Eriocheir sinensis > Eriocheir leptognathus > benthic fish > pelagic fish > bottom water > surface water. Tissues in fishes and crabs of different species and sizes had diverse metal bioaccumulation characteristics, which was significantly affected by environment factors and their living habits. Metal levels in legs of crabs, and heads and skins of fishes showed significant correlations with those in their living environments. Collichthys lucidus is an effective bioindicator for assessing metal levels in water. No significant health risk was identified by the estimated daily intake and target hazard quotients analyses. 相似文献
20.
A. Gmez-Parra J. M. Forja T. A. DelValls I. Senz I. Riba 《Marine pollution bulletin》2000,40(12):1115-1123
The Guadalquivir estuary was impacted by the accidental release of 5 million cubic meters of acid waste from the processing of pyrite ore (25 April 1998). The waste entered ecologically sensitive and protected areas such as the National Park of Doñana. Here are presented the results obtained from a time sequence of different sampling sites in the estuary and in the surrounding areas from May to September 1998. Water, suspended solids and sediments were analysed for six different metals (Fe, Mn, Zn, Cd, Pb, Cu). Also, the concentration of the metals in the different geochemical sediment fractions was determined as a means of assessing bioavailability. The results obtained during the first weeks after the incident show high concentrations of Zn. At the end of June a 10 000 m3 temporary water-treatment plant was constructed on site for depuration of the toxic waters. The results obtained in August and September show a decrease in the metal concentrations measured in the estuary. Only concentrations of Zn were higher than sediment quality values proposed by various authors. 相似文献