Metal Pollution In Sediments Research Articles

Heavy metals in sediments, mussels and oysters from Trinidad and Venezuela.

The Gulf of Paria is bordered by both Trinidad and Venezuela, from which various metallic pollutants and other contaminants can originate. The Gulf is still a significant source of fish, crabs and shellfish for human consumption to both countries, where concerns over the quality of this marine environment have been long expressed but never properly addressed. In addition, the circulatory current patterns in the Gulf ensure that contaminants originating from either country are likely to affect both countries eventually. Heavy metals were determined in oysters (Crassostrea rhizophorae and C. virginica), green mussels (Perna viridis) and sediments from the Gulf of Paria. Samples were obtained at four sites in Trinidad and three sites in Venezuela in the Gulf of Paria, in addition to comparative samples collected from three sites on the north coast of Venezuela. Edible tissues of twelve shellfish from each location were blended and aliquots digested with concentrated nitric acid, for extraction of cadmium, chromium, copper, lead, nickel and zinc. The solutions were analysed by flame atomic absorption spectroscopy. Mercury was extracted with a mixture of nitric, hydrochloric and sulphuric acids and determined by cold vapour atomic absorption. Sediments were oven-dried at 60'C, before being similarly extracted. Results showed that mercury in sediments at all sites in Trinidad and Venezuela exceeded NOAA and Canadian sediment quality guidelines, while cadmium, copper, nickel, lead and zinc also exceeded these guidelines at several sites. Heavy metal levels in oysters and green mussels varied widely with location. However, oysters from the Gulf of Paria contained significantly higher mean levels of cadmium, copper, nickel and zinc than those from the north coast of Venezuela, but this difference was not apparent in mussels. Cadmium, mercury and zinc in sediments were significantly correlated with those of mussels, but not of oysters, in which copper and zinc at several sites in the Gulf of Paria exceeded local maximum permissible levels (Cu = 20 microg g(-1) wet wt; Zn = 50 microg g(-1) wet wt) for human consumption. These findings indicate that while mussels may be better biological indicators of heavy metal pollution in sediments than oysters, the latter may provide copper and zinc contamination. Further research is needed to determine the most appropriate biological indicators of heavy metal and other pollutants in the local marine environment and to develop protocols for their use.

Changes in benthos following the clean-up of a severely metalpolluted cove in the Hudson River estuary: Environmental restoration or ecological disturbance?

We studied changes in macrobenthic communities following the environmental clean-up of metal-polluted (cadmium, nickel, and cobalt) sediments in Foundry Cove, a small inlet within the Hudson River estuary of New York. We used a BACI-style experiment to test the hypotheses that high levels of cadmium in sediments change macrobenthic assemblages relative to unpolluted areas, and removal of metals (especially cadmium) by dredging will restore the benthos, such that benthic fauna in Foundry Cove are not different from unpolluted areas. In 1984, prior to the restoration work, there were no significant differneces between macrobenthic assemblages in polluted and unpolluted locations, indicating that cadmium had little effect on community structure. The lack of an observed toxicity effect may have been caused by the compensatory evolution of resistance to cadmium in dominant organisms. Six years after the restoration work and despite a substantial reduction in metal pollution, there were lower abundances of oligochaetes, nematodes, and chironomids and a higher abundance of polychaetes at Foundry Cove relative to reference locations. Correlative analyses identified greater sediment compaction caused by dredging at Foundry, Cove as a possible cause of faunal differences. The results demonstrate that it is difficult to accurately predict, the effects of anthropogenic disturbances and restorations in complex natural systems and that unforeseen side effects are inevitable. Documenting these unpredicted effects and experimentally understanding their causes in past restorations will greatly improve the success and cost-effectiveness of future projects of a similar type.

Conditioning of Freshly Dredged Heavy Metal-Polluted Aquatic Sediment with Reed Canary Grass (Phalaris arundinacea L.)

The remediation of heavy metal-polluted sediment by solid-bed bioleaching, using the percolation principle, requires a material well permeable to air and water. Freshly dredged sediment is nearly impermeable, unsuitable for solid-bed leaching, and therefore needs preliminary conditioning. During conditioning, the sediment underwent physicochemical changes such as oxidation and acidification, which were significantly accelerated by the presence of reed canary grass (Phalaris arundinacea L.) in comparison to the processes taking place in sediment without plant cover. P. arundinacea transpired large amounts of water followed by the formation of cavities in the sediment package which were then penetrated by atmospheric oxygen. Furthermore, P. arundinacea actively transported oxygen into the sediment via the roots. Oxygen and root exudates stimulated the growth of microbes, which together with hair roots made mineral sediment particles stick together, forming larger aggregates and changing the sediment structure from muddy-pasty to crumbly and soil-like. The structural changes markedly improved the permeability of the sediment to water by a factor of 5,000. Sediment conditioned with P. arundinacea consisted of larger and more stable particles and therefore it was twice as permeable as unplanted sediment. Comparative solid-bed bioleaching experiments on a pilot scale demonstrated that the removal of heavy metal occurred at nearly the same rate and efficiency with conditioned (for six months with P. arundinacea) and spontaneously ripened (stored for six years in the open) sediment.

Conditioning of Heavy Metal-Polluted River Sediment by Cannabis sativa L.

ABSTRACT We are currently developing a process for the remediation of heavy metal-polluted sediment by solid-bed bioleaching. Unfortunately, freshly dredged sediment is impermeable to water, unsuitable for solid-bed leaching, and therefore needs preliminary conditioning to improve its structure. A pilot-scale conditioning plant consisting of several basins (each with a base of 6 m2 and a depth of 0.7 m) was filled with freshly dredged, slightly predewatered sediment from the Weisse Elster River. Hemp (Cannabis sativa L.) was chosen for conditioning because it develops quickly from seeds, produces large amounts of biomass, and forms commercially useful fibers. Irrespective of the plant cover, the sediment dried out, was oxidized and turned acidic. However, its structure and permeability only improved when the sediment was covered with plants and not when all the vegetation appearing was removed regularly. Although hemp germinated completely regularly on sediment, 1 week after seeding the leaves became partially discolored, deformed, and dry, and ultimately about 95% of all the hemp plants died. The surviving hemp produced shorter shoots and much lower amounts of biomass than hemp on unpolluted soil. Studies in pots and hydrocultures indicated that the inhibition of hemp growth is caused by the synergistic action of a low pH and several mobile toxic metals. Hemp on sediment incorporated much higher quantities of heavy metals (especially Zn, Cd, and Ni) than hemp on unpolluted soil, which calls the commercial use of the former seriously in question.

Heavy metal pollution in sediments of the Pasvik River drainage

The purpose of this paper is to study the regional impacts of heavy metals (Ni, Cu, Co, Zn, Cd, Pb, Hg) on the watershed of the Pasvik River. On the basis of sediment investigations at 27 stations of the watershed, background concentrations of the heavy metals, vertical distribution of heavy metals in sediments, heavy metal concentrations in surface sediments, contamination degree, and risk index were determined. The atmospheric emissions of Ni, Cu, Co, Zn, Cd and Hg from the smelters and waste waters from tailing dams and mines of the Pechenganickel Company are likely to be the main sources of increasing concentrations observed in recent sediments of the lower river reaches. Lead showed a different pattern from the other heavy metals—increasing Pb concentrations in the upper sediment layers towards the Norwegian side.

Role of monsoon rain on concentrations and dispersion patterns of metal pollutants in sediments and soils of the Ganga Plain, India

Monsoon rain causes large scale sediment-water movement and reworking of sediments of the Ganga Plain which is one of the largest fluvial systems on Earth. Geomorphology and drainage type combined with sedimentation processes play a substantial role on dispersion and transport patterns of metals bound to sediments and soils. The study area of Kanpur-Unnao industrial region in the Ganga Plain has been divided into five independent geochemical domains on the basis of sediment-geomorphic, hydrological and geochemical characters. The monsoon hydrography and physico-chemical parameters (pH, conductivity) of the river and urban drain waters play a prominent role in regulating the concentrations and behaviour of the metals in the aquatic system of the Ganga Plain. Values of pH and specific electrical conductivity of the river water of the study area decrease whereas those of the urban drain water increase in post-monsoon period. The monsoon rain reduces the contents of Co, C-org, Cr, Fe and Ni and enhances the contents of Cd, Sn and Zn in sediments of post-monsoon period. In soils, it reduces the contents of Al, Co, Fe, Mn and Ni and enhances the contents of Cd, Sn and Zn in the post-monsoon period. These changes in concentrations vary from metal to metal and from one geochemical domain to the other. An increase in the concentrations of few metals in the soils from pre- to post-monsoon periods indicates that these metals were mobilized from the overflooding of metal rich waste-water onto the fields during high water stage and also by reworking of the soils through sheet floods during the monsoon time. Despite the changes in concentrations, metal dispersion patterns in each domain remain similar both in pre- and post-monsoon periods which indicate that the geochemical and sediment-geomorphic processes operating for the metal dispersion and mobilization in sediments are persistent even after large scale sediment-water movement and reworking of the sediments during the monsoon period.

Necessity of Combining Geochemical and Geomorphic Processes Addressing Pollution Problems in the Fluvial System of the Ganga Plain, India

The Ganga Plain is one of the largest alluvial plains of the earth. It is a huge natural laboratory to test a number of hypotheses on sedimentary and geochemical processes of past and present. For several decades, the indiscrimate use of the drainage basin of Ganga Plain for the disposal of domestic and industrial wastes has adversely effected the quality of water, sediments and agricultural soils. The mobilization of various metal pollutants in sediments of this highly dynamic fluvial system is a complex process in which sediment-water movement is extremely variable due to their continuous input from the Himalaya and southern India under changing hydrological conditions (e.g. Monsoon). The present study was aimed at quantifying the level of geogenic and anthropogenic metal pollutants (A1203, Cd, Co, Cr, Cu, Fe203, Ni, Pb, Sn, and Zn) in different hydraulic conditions (e.g. Monsoon), and their dispersion and mobilization processes in various eco-compartments (sediment, water and soils) of the fluvial system of the Ganga Plain. This plain has different geomorphic surfaces and features whose role and control on dispersion patterns of metal pollutants in sediments and soils has been demonstrated. In sediments, about 90 % of the contents of Cd, Cr and Sn, 50-75 % of Cu, Zn and C-org, and 25 % of Co, Ni and Pb; and in soils about 90 % of the contents of Cr and Sn, about 75 % of Cd, and about 25 % of C-org, Cu, Ni, Zn respectively are of anthropogenic origin. Surface and pore water of this

Kinetics of metals in molluscan faecal pellets and mineralized granules, incubated in marine sediments

Marine snails excrete metals via the gut. The sediment-feeding, tower shell Cerithium vulgatum, from a polluted environment, accumulates Cr and Ni to 3500 ppm dry weight in the faecal pellets. Pellets from C. vulgatum and the grazing, top shell Monodonta mutabilis were incubated in surface and deeper anoxic layers of clean and metal-polluted sediment. Pellets retained the original load of metals and in some cases gained Ti, Cr, Mn, Fe and Ni. Effects were modified by sediment properties. Pellets of C. vulgatum are durable, membrane-bound structures and they reduce metal bioavailability to food chains by compartmentalization. Intracellular, phosphate granules bind metals in digestive glands of snails and they are excreted via the gut and faecal pellets. These granules were extracted from digestive glands of both species of snail and incubated in the same sediments. Magnesium phosphate granules from M. mutabilis dissolved but calcium/metal phosphate granules from C. vulgatum remained; they had differentially retained or lost Mn, Fe, Co, Ni and Zn according to the type of sediment.

Heavy Metal Pollution in Sediments and Waters of the Penang River, Malaysia

Abstract The concentrations of zinc, copper, lead and nickel in the Penang River and its tributaries were determined to assess the extent of heavy metal pollution, and to evaluate which compartment provides a better indicator for heavy metal pollution. The results indicate that the concentrations of total and non-residual heavy metals in sediments increase significantly towards the estuary of the river. This trend is, however, not obvious for heavy metals in the river water. The data indicate that assessment of heavy metal pollution in rivers could be made by using the data of heavy metal levels in river sediments. It is suggested that non-residual heavy metal levels in sediments give the best indication of anthropogenic input of heavy metals to river systems.

Heavy Metal Pollution in Sediment from the Eastern Adriatic Coast, Croatia

Abstract Sediment samples were collected from the Adriatic Sea in areas near large coastal towns along the eastern Adriatic coast (Zadar, [Ncirc]ibenik, Split, Ploĉe and Dubrovnik). Considerable quantities of untreated effluents are discharged via freshwater runoff and a variety of industrial waste waters, significantly affecting the quality of marine sediments. Distribution of some trace metals (Pb, Cu, Ni, Cr, Zn, Mn, Cd, and Al) involved in problems related to metal pollution in Adriatic sediment were examined. Values are expressed as a total concentration of heavy metals of sediment dry weight. Spatial distribution of some trace metal values in sediments and correlation of results for grain size effect were examined. the trace elements in marine sediments generally remain in the fine grained fraction, often in the silt-clay fraction. Higher values of heavy metals in some areas (Split, Sibenik) could be attributed to anthropogenic effects, i.e. to land-based activities. the main cause of higher values of some metals at open sea sites and in some coastal areas are probably caused naturally by sedimentation processes in those areas. Our results show that the sediments undoubtedly play a key role in determining the transport and ultimate fate of contaminants.

Elemental concentrations and heavy metal pollution in sediments and suspended matter from the Belgian North Sea and the Scheldt estuary

The elemental composition of sediment and suspended matter samples from the Belgian coastal and offshore regions of the Southern Bight of the North Sea and from the Scheldt estuary has been determined using X-ray fluorescence and atomic absorption spectrometry. Special attention was given to the heavy metals of the black and the grey lists. The bulk sediment and the clay/silt fraction were analyzed. The average heavy metal contents in the fraction <63 μm were comparable to the levels in the suspended matter. Different normalization techniques led to the identification of two different populations of sediments. Most of the sediments were enriched in Cd, Cr, Hg, Pb and Zn but no enrichment was found for Cu and Ni. Comparing these data with older data indicates that little changes in the metal contamination of the sediments in the area investigated has occurred over the last 15 years.

Metal pollution in sediments of Jamaica Bay, New York, USA—An urban estuary

Calculations of the annual input of heavy metals to Jamaica Bay, New York, USA, reveal that sewage effluent carries the largest quantities of Ni, Zn, Cu, and Cd to the bay. Storm sewers and atmospheric fallout are the main sources of Pb. Atmospheric fallout of Zn, Cu, and Cd, although smaller than the combined input from sewers, contributes a significant fraction of these metals. The metal input from landfill leachate is far smaller than that from other sources. Analysis of available data shows that metal concentrations in the sediment of the bay correlate with each other and with percent total organic carbon (%TOC). This is consistent with the observation that the input of metals is predominantly associated with sewage. It is demonstrated that metal-TOC ratios, rather than metal concentrations, must be used in efforts to detect local intensive sources of metals in solution; metal-TOC ratios in intertidal sediment adjacent to these landfills are elevated by the adsorption of leachate metals, while metal concentrations are not. Subtidal sediment within a few hundred meters from two landfills shows no evidence of the addition of metals from that source, which is consistent with the small input of metals estimated for these landfills. The evidence cited in this study sharply contradicts the implication made in a widely publicized report issued by an environmental advocacy group that a significant link exists between metals found in subtidal sediment of Jamaica Bay and landfill leachate.

Heavy metal pollution in sediment from the Seto Inland Sea, Japan

To discuss the geochemical and environmental behaviors of heavy metals in the Seto Inland Sea which is the largest semi-closed coastal sea in Japan, (1) distributions of heavy metals concerning pollution were examined and (2) mass balances of Zn and Cu were studied by applying a simple box model. Increase in heavy metal contents of core sediments already started in the late 1800s and is considered to be due to human activities. Recently, the pollution of sediment in Osaka Bay which is most contaminated sea area in the Sea, seems to have tended to decrease. In 1980, total sedimentary loads of Cu and Zn over the whole area of the Sea were estimated to be 630 and 3,500 tons/yr, respectively. Further, the sedimentary loads without and with human activities were estimated separately to be, respectively, 320 and 310 tons/yr for Cu and 1,800 and 1,700 tons/yr for Zn. Total inputs of Cu and Zn into the Sea were estimated to be 870 and 4,250 tons/yr and about one half of this being the results of human activities. 70% of the Cu input and 80% of the Zn input are accumulated into the sediments.

底質の重金属汚染

底質の重金属汚染

Sedimentation rates and heavy metal pollution of sediments in the Seto Inland Sea

In the Suo-Nada area of the Seto Inland Sea, Japan, sedimentation rates and the sedimentary record of anthropogenic metal loads were determined by combining the Pb-210 dating technique with heavy metal analysis of the sediments. The sedimentation rates vary from 0.11 to 0.27 g cm−2 yr−1. Lower sedimentation rates were observed in the eastern part of the basin which is characterized by a bottom with sand and gravel, and fast tidal currents.

Sedimentation rates and heavy metal pollution of sediments in the Seto Inland Sea

Sedimentation rates and heavy metal pollution of sediments in the Seto Inland Sea

Sedimentation rates and heavy metal pollution of sediments in the Seto Inland Sea

Sedimentation rates and heavy metal pollution of sediments in the Seto Inland Sea

Sedimentation rate and heavy metal pollution in sediments in Harima Nada (Harima Sound), Seto Inland Sea

Sedimentation rates were determined with the210Pb technique in six sediment cores from Harima Nada (Harima Sound), Seto Inland Sea. The rate of deposition varies from 0.11 g cm−2y−1 in the northern part to 0.33 g cm−2 y−1 in the southern part of the basin. A marked increase in copper and zinc content was observed above a depth in the core corresponding to about 1900 A.D. as a result of increasing human activities. Anthropogenic input of copper and zinc decreased slightly after 1970. Natural background levels of copper and zinc in the sediment in this sound are 11–16 ppm and 100–120 ppm, respectively. The total amounts of anthropogenic copper and zinc in the sediments were estimated to be 110–180μg cm−2 and 610–1,280μg cm−2, respectively. These values constitute 40–50% of the total sedimentary input of copper and zinc in the sediments since about 1900 A.D.

Historical Records of Metal Pollution in Sediments of Toronto and Hamilton Harbours

The sediments of Hamilton and Toronto Harbours contain some of the oldest records of metal pollution in the Great Lakes basin. The fluxes of Cd, Cr, Cu, Ni, Pb, Zn, Fe, and Mn into the two harbours have been estimated from the analyses of core samples dated by the Pb-210 technique. The contrasting metal levels in the two harbour sediments are viewed in relation to the differences in the disposal strategies of the dredged spoils and the sources of metal pollution in the harbours. The Zn and Fe concentrations of 5 to 8 mg g −1 and 10 to 13 % dry wt. in Hamilton Harbour sediments, which are among the highest recorded in any harbour, can be related to effluent discharges from the large local iron and steel plants. An inventory of the sources and sinks of pollutant metals in Hamilton Bay shows a substantive export of the metals to Lake Ontario.