Metal fluxes to the sediments of the northern Venice Lagoon

Eighteen short cores were analyzed for major and trace metals (Al, Fe, Ca, Mg, Mn, Si, K, Ti, Pb, Zn, Cu, Ni, Cr), ²¹⁰Pb, ¹³⁷Cs, and other sediment characteristics, so as to describe the chronology of pollution and calculate metal concentration factors and fluxes. Substantial evidence was found that trace metal profiles are influenced by anthropogenic sources and by changes in sediment composition. Only Zn presents concentrations (up to 13.1 μmol g⁻) and concentration factors (1.3 to 13.2) that can be attributed to heavy contamination. Pb, Cu and Ni, in this order, are less significant. The areal distribution of concentrations and inventories reflects the importance of direct sources, in particular the industrial area of Porto Marghera and the Dese river. The inventories of excess metals, above pre-industrial levels, were determined for each core and the three different parts of the study area, the amounts of Zn accumulated in sediments are 11.0 Mmol, 5.1 Mmol and 0.37 Mmol in the Campalto, S. Erasmo, and Palude di Cona areas, respectively. Ruxes were also calculated and compared with those suggested for the atmospheric delivery by Cochran et al. [(1995)b. Atmospheric fluxes of heavy metal contaminants to the Venice Lagoon, Rapp. Comm. Int. Mer Médit., 34, 136.], the atmospheric contribution is predominant or significant in many cases, especially at sites far from the major local inputs. Concentrations and fluxes show a significant increase in the anthropogenic metal supply starting from the second decade of this century, with maximum inputs in the period between the (1930)s and the (1970)s. At some stations a decrease in heavy metal contamination of surficial sediments was found and this could be ascribed to a reduced input of pollutants in recent years.     

Resuspension-induced partitioning of organic carbon between solid and solution phases from a river–ocean transition

Laboratory experiments were conducted to evaluate the net exchange of organic carbon (OC) between sediments and overlying water during episodes of resuspension. Surface sediment samples collected from six locations within the Hudson River Estuary and the Inner New York Bight were resuspended in their respective bottom waters for periods ranging from 30 s to 2 h. After resuspension, dissolved organic carbon (DOC) concentration generally reached levels greater than that predicted by conservative mixing of pore water and bottom water, indicating net release of OC from the sediment particles. The amount of OC released during the 1-h extractions comprised ≤0.1% of the total sediment pool, but correlated positively (R²=0.65, P<0.052) with the amount of particulate organic carbon (POC) found in the high-density fraction of the sediment matrix. This suggests that the mineral-bound fraction of sedimentary OC was the major source for the excess DOC released into solution, and that across various sedimentary environments, only a small (but fairly constant) fraction of the total sedimentary POC may be poised for rapid transfer to the water column.     

Metals background and enrichment in the Chiloé Interior Sea sediments (Chile). Is there any segregation between fjords,channels and sounds?

The range and spatial distribution of metal concentrations in the Chiloé Interior Sea were investigated from 37 surface sediment samples collected during the ‘CIMAR 10 Fiordos’ cruise. Grain size distribution, total organic carbon and nitrogen, δ¹³C, major (Al, Fe, and biogenic opal) and trace (Cd, Co, Cu, Ni, Pb, and Zn) elements were determined. Metal background concentrations of each metal in sediment were defined from linear regression equations of metal versus Al, as baseline information for future research on the status of sediment contamination in the Northern Patagonian marine area. Metal levels in Chiloé sediments were of the same order of magnitude as uncontaminated sediments around the world and contamination can be considered negligible-moderate (normalized enrichment factors lower than 3) in this Southern Pacific Region. The Chiloé Interior Sea can be segregated into two zones on the basis of metal content by applying a principal component analysis. The first pertains to inner fjords and it has terrestrial origin (associated to Co, Cu, Pb, Zn) and the second zone features channels and gulfs of a predominantly marine source (Cd, Cu). Nevertheless, only one background equation is needed to predict metal concentrations in the natural sediment of the Chiloé Interior Sea.     

Decline in heavy metal contamination in marine sediments in Jakarta Bay,Indonesia due to increasing environmental regulations

The ²¹⁰Pb geochronology, heavy metal concentrations (Zn, Cu, and Pb), and stable Pb isotope ratios (²⁰⁶Pb/²⁰⁷Pb) of three sediment cores collected from Jakarta Bay were analyzed to decipher the history of heavy metal contamination in the period 1900–2006. The chemical and isotopic analyses clearly suggest that anthropogenic metal accumulation in the sediments began in the 1920s and increased greatly from the 1970s until the end of the 1990s. From the end of the 1990s to 2006, accumulation rates were constant or decreased for Zn and Pb near the coastal industrialized area. Comparison of economic data and sociological information suggests that the decline in the concentrations of heavy metals could be attributed to the stricter environmental regulations which were enforced at the end of 1990s. However, metal contamination is currently still an important cause of concern in dealing with environmental preservation and protection in Jakarta Bay.     

Gill fouling and parasitism in the rock crab, Cancer irroratus say

Rock crabs, Cancer irroratus, were examined grossly and microscopically to estimate the influence of molting activity, geographical source and seabottom sediments on gill color, carapace color and tissue pathology. Collections were made from deepwater stations (20–55 m) in the Hudson Shelf Valley near dredge- and sewage-sludge disposal sites in the New York Bight apex, and from nearshore waters near Boothbay Harbor, Maine. Extensive gill blackening was noted in up to 30 % of the crabs from the New York stations when all specimens were in the intermolt condition. Blackening was not noted in intermolt crabs collected in Maine. Carapace blackening was present in up to 79 % of the New York crabs but absent in those from Maine. Severe blackening was attributed to direct contact of Cancer irroratus with blackened, highly organic sediments in the Hudson Shelf Valley. Fouling microorganisms on gill epicuticle included bacteria, diatoms, stalked ciliates, amoebae, flagellates and copepods. Bacteria, diatoms, amoebae and flagellates were common on crab gills from both locations. Ciliates and copepods counted in histological sections were considerably fewer in crabs from the New York stations than in those from Maine. Melanized nodules (hemocyte clumps) were present in gill tissue in up to 58 % of the New York crabs and in up to 68 % of Maine crabs. Unidentified microsporidans were found in up to 55 % of the New York specimens and in less than 2 % of those from Maine. Histological data accumulated since 1975 are summarized to provide a list of endoparasites, polychaete worms and barnacles observed in Cancer irroratus from the northeastern United States. Gill blackening, but not parasitism or microbial fouling, proved to be the best indicator or monitoring the effects of ocean dumping on the health of a benthic crustacean species.     

连云港对虾养殖区表层沉积物重金属污染评价

在2010年6月对连云港市对虾养殖区的沉积物环境状况进行这站调查,分析了对虾池养殖区表层沉积物中重金属的含量及分布,并采用海洋沉积物质量国家标准和地积累指数法对该养殖区沉积物中重金属污染进行了评价。结果表明: (1)Cu、Zn、Pb、Cd、Hg、Cr、As的平均浓度分别为22.31 mg/kg、283.9 mg/kg、64.86 mg/kg、0.58 mg/kg、0.0056 mg/kg、89.23 mg/kg、35.58 mg/kg,通过计算单项污染指数表明所有元素的污染指数均在 0～1 之间,属于非污染,表明虾池沉积物属于清洁土壤。(2)利用地积累指数 (Igeo)法对所得到的调查结果进行了评价,发现各样点沉积物呈现出轻洁至中等的污染程度,参与评价的6种重金属的污染程度依次为As> Zn> Pb、Cd> Cr> Cu。进一步的生态风险评价结果表明,所有站位沉积物Cu和Cd（除站位5）的含量皆低于ERL值,说明Cu和Cd很少产生不利的生态效应;全部站位的重金属Zn、Pb和8个站位的Cr的含量均在ERL和ERM之间,表明这三种金属偶尔产生不利的生态效应。     

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.     

The wreck of the MV Rena: spatio-temporal analysis of ship-derived contaminants in the sediments and fauna of Astrolabe Reef

ABSTRACT

The October 2011 sinking of the container ship MV Rena on Astrolabe Reef, New Zealand, provided a rare opportunity to examine the fate of shipwreck-derived contaminants on an offshore rocky reef and food chain. Analyses of trace metals, polycyclic aromatic hydrocarbons (PAHs) and organotins indicated significant but localised contamination of Astrolabe Reef but not of nearby Mōtītī Island. Three years after the grounding, PAH concentrations were greater in sediments at Astrolabe (up to 131?mg kg^?1) than at control locations, while organotins from the ship's antifouling hull paint were found exclusively in Astrolabe Reef sediments and biota. Over 80% of Astrolabe sediment samples contained tributyltin at concentrations above guideline sediment levels (>0.07?mg kg^?1). Tributyltin and its decomposition products were also recorded in sea urchins, gastropods, lobster and fishes at concentrations up to 0.2?mg kg^?1. Wreck and cargo-derived metals, particularly copper, tin and zinc, were present in some Astrolabe sediment samples above Australia and New Zealand Environment and Conservation Council guideline concentrations. However, there appeared to be only limited transmission of metals through the food chain. Copper, tin and zinc were recorded at greater concentrations in Astrolabe sea urchins and gastropods compared to control specimens, while metal concentrations in other biota were comparable across impact and control sites. Despite over 3 years having passed since the Rena grounding, the data series does not show any upward or downward trends in contaminant concentrations on Astrolabe Reef. Consequently, there is uncertainty about the long-term implications of the Rena grounding for the ecology of Astrolabe Reef.     

Input of river-derived sediment to the New Zealand continental shelf: I. Mass

The input of river-borne sediments to the New Zealand continental shelf has been calculated for all the major rivers and basins in New Zealand. South Island yields 284 ± 40 × 10⁶ tonnes per year of sediment from a land area of 152 977 km² and North Island yields 105 ± 9·4 × 10⁶ tonnes per year from a land area of 114 621 km². Particularly high discharges are noted off the west coast of South Island and east coast of North Island and result in higher offshore sedimentation there. The data are compatible with measured sedimentation rates on the New Zealand continental shelf. The specific sediment yield from South Island is amongst the highest previously recorded.     

Dispersion and accumulation of radionuclide in sediment of Urazoko Bay-II

Further studies on the transport in sea water and accumulation in marine sediment of the radionuclides, released from a nuclear power plant, on Urazoko Bay, Fukui Prefecture were reported.The partition of radionuclides among the particle size fractions of a sediment sample indicated that the accumulation of⁶⁰Co,¹³⁷Cs and⁵⁴Mn in the sediment were dominated substantially by the sorption on the particle surface in sea water, and the patterns of their sorption were considerably similar to each other.In regard to the⁶⁰Co contamination of marine sediments in an area of about 13 km² around the nuclear power plant, 60% of the⁶⁰Co contamination were retained in Urazoko Bay, which occupies only 7% of the bottom surface of the region.It is clear that a part of⁶⁰Co accumulated in the sediment of Urazoko Bay gradually moved to the outerward.     

The accumulation of Zn, Se, Cd, and Pb and physiological condition of Anadara trapezia transplanted to a contamination gradient in Lake Macquarie, New South Wales, Australia

The benthic bivalve, Anadara trapezia, was collected from a 'clean' reference site and transplanted along a suspected trace metal contamination gradient in Lake Macquarie, NSW. At monthly intervals, Zn, Se, Cd and Pb concentrations were measured in the surficial sediments and whole tissues of the cockle as well as their physiological condition (Scope for Growth). Zinc, Cd and Pb concentrations in sediments decreased together, southward, with the highest concentrations in the Cockle Bay area, suggesting that this is the main source of contamination. Zinc, Cd and Pb concentrations were near or above [ANZECC/ARMCANZ, 2000. National water quality management strategy paper 4. Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Australian and New Zealand Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand. pp. 3.5.-1-3.5-10] sediment quality guidelines at Cockle Creek, Warners Bay and Koorooa Bay. Significant differences in trace metal concentrations could not be attributed to grain size or Fe concentration differences. Se concentrations were highest in fine grain Fe rich sediments of Whiteheads Lagoon, and likely to be associated with power generation operations. Trace metal concentrations did not vary significantly over time. Zinc, Cd and Pb concentrations in the tissues of A. trapezia followed a similar pattern to that of sediments. Zinc and Pb concentrations in cockles and sediments were highly correlated, indicating significant exposure-dose relationships. Selenium concentrations in the tissues of A. trapezia were higher after transplantation to the lake, however, Se concentrations were similar in all transplanted cockles, indicating that Se in contaminated sediments is not the major source of Se to organisms. There was a decline in the physiological condition of A. trapezia transplanted to Lake Macquarie after a 90-day-period with marked differences in clearance rates and respiration rates at some locations and absorption efficiencies at all locations. The mean Scope for Growth value at the most contaminated location, Cockle Bay, was markedly lower than at other locations. A significant Zn exposure-dose response relationship indicates that Zn bioaccumulation is occurring in response to sediment contamination. A significant Cd exposure-response relationship indicates that Cd may be influencing the health of cockles. Significant Pb exposure-dose, exposure-response and dose-response relationships indicate that Pb probably is affecting the health of cockles in Lake Macquarie. Therefore, Zn, Cd and Pb concentrations in sediments are likely to be affecting the health of cockles in Lake Macquarie.     

Integrated coastal zone management at Marina di Carrara Harbor: sediment management and policy making

Sediment management is becoming a critical issue around the world, particularly where the development of Harbor facilities, the conservation of coastal environments and needs of tourism compete for sustainable use of sediment resources. In order to apply an Integrated Coastal Zone Management policy, new approaches for management of the dredged harbor material need to be considered by the scientific community and local stakeholders. The information contained in the Italian Ministry of the Environment Acts related to dredging of Carrara Harbor determined the sediment volume dredged between 1993 and 2008 (849,500 m³) and allows us to estimate an average rate of material dredged from the harbor mouth (10,000-13,000 m³/yr). Different management options were chosen by the authorities based on the contamination level of dredged sediment: nourishment (344,500 m³), offshore dumping (305,000 m³), disposal in landfill (10,000 m³) or in Confined Disposal Facilities (215,000 m³). The present study’s goal is to determine the sedimentary budget of the Apuo-Versilian coast and to use the result to guide a compensation strategy to reduce the sediment deficit caused by the disposal of sediments out of the sand-sharing system. In particular, the present study provides a detailed reference frame that can lead to adopt a compensation strategy to balance the eroding evolutionary trend of the coastline adjacent to shallow water dredging areas. The procedure described in the paper is a policy initiative based on scientific results and could provide a model for other jurisdictions developing their own sediment quantitative estimation within an ICZM approach and a sustainable development of sedimentary resource’s management.     

Assessment of metals in sediments from Lake Macquarie, New South Wales, Australia, using normalisation models and sediment quality guidelines

Industrial activity since the 1890s and, more recently catchment development has resulted in significant metal contamination in Lake Macquarie, an estuary in New South Wales, Australia. This paper presents an analysis of metal concentrations in surface sediments from Lake Macquarie using normalisation models to estimate enrichment relative to natural background concentrations and by comparing concentrations with sediment quality guidelines (SQGs) and effects range median quotients to assess the potential for ecological harm. Of the 12 metals examined, cadmium, lead, mercury, selenium, silver and zinc were enriched in surface sediments throughout the lake. The greatest contamination was found in the north of the lake and, for selenium, also in areas adjacent to two power stations. Comparisons with SQGs and effects range median quotients found that sediments from a site in Cockle Bay had concentrations of metals with the highest likelihood of causing adverse effects on sediment associated biota, and that the likelihood adverse decreased with distance from Cockle Bay. Comparisons with historical sediment quality data indicated that there has been a marked reduction in surface metal concentrations throughout the lake over 15 years. Models could not be constructed for all metals due to low background concentrations. For most metals, simple linear regression models were adequate, but for selenium and arsenic a multiple regression model provided a better estimate of background concentrations. SQGs possibly overestimated effects for arsenic, which has naturally high concentrations in the lake and underestimated the potential for ecological effects in coarser sediments.     

A Mössbauer spectroscopic and X-ray diffraction study of the iron mineralogy of some sediments from the Southwestern Pacific Basin

The results of a ⁵⁷Fe Mössbauer spectroscopic and X-ray diffraction study of four pelagic clay sediments from the Southwestern Pacific Basin collected at increasing distances from New Zealand, on a New Zealand—Rarotonga transect, are presented. These show that, with increasing distance from New Zealand, the Fe³⁺/Fe²⁺ ratio of the sediment increases as a result of the increasing contribution of the X-ray amorphous secondary hydrous iron oxides, notably ferrihydrite, due to the longer sedimentation periods and consequent greater degree of oxidation of the sediments. This increase in the Fe³⁺/Fe²⁺ ratio is correlated with the change in colour of the sediments from pale yellowish to dusky brown, as well as a number of other sediment parameters. Apart from a slight increase in the relative abundance of montmorillonite with increasing distance from New Zealand, the abundances of the other clay minerals, illite and kaolinite, and of chlorite in the sediments are approximately equal. Quartz and feldspar with minor augite are the dominant detrital minerals. Calcite is present in minor amounts in some of the sediments.     

Side-looking sonar backscatter response at dual frequencies

Dual-frequency side-looking sonars have the potential to be used as remote sensing tools to characterize subaqueous terrains. In one case study of the carbonate-ooze-coated Blake Plateau off-shore of Georgia, U.S.A., the difference in acoustic attenuation for 50 and 20 mm wavelengths (30 and 72 kHz frequency) permits the discrimination of sub-bottom scatterers from seabed surface textural features to reveal patchy regions where a buried hard ground had been pock-marked by karst-like depressions. In a second study of the Upper Hudson River in New York, U.S.A., related to environmental contaminates, the backscatter response at 15 and 3 mm acoustic wavelengths (100 and 500 kHz frequency) serves as a useful proxy for sediment grain size with coarser detritus distinguished from finer sediments. Sand and gravel regions inferred from the backscatter were confirmed by ground truth sampling.     

Heavy metals in a contaminated Australian estuary—Dispersion and accumulation trend

Very high concentrations of Zn, Pb, Cu and Cd occur in the muddy bottom sediments of Lake Macquarie, a saline coastal lagoon in southeastern Australia. The trace metals emanate from industrial sources, especially a lead-zinc smelter, at the northern end of the lake. Individual metal concentrations decrease progressively away from the source area but at differing rates; Zn is most mobile and Cd appears to be deposited first. They approach natural background levels in the southern part of the lake. Mn shows a reverse trend but Ni, Co, Ag and Fe rarely rise above background levels.Shallow cores in the lake bed penetrated a metal enriched surface zone 15–35 cm thick underlain by uncontaminated sediments with natural (background) metal concentrations. Sedimentation rates determined from radiocarbon ages on shells in the cores mainly range between 0·15 and 0·5 mm yr^?1. Over the 85 years since industrialization commenced, less than 5 cm of mud has accumulated on the lake bed. Bioturbation is invoked to account for the depth to which the sediment has been enriched in heavy metals.     

Multivariate geochemical investigation of trace metal pollution in Kuwait marine sediments

Three multivariate procedures (cluster analysis, discrimination and classification) were used to identify and characterize various types of marine sediments in Kuwait. Samples from 201 offshore locations were first clustered into five types of sediments with different metal concentrations (Ag, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn and Hg) and sedimentological characteristics (% TOC, carbonate, mean grain size and % size fraction < 63 μ). Discriminant functions were then developed in terms of trace metal concentrations to describe mathematically differences between the various sediment types. A classification procedure was also used to calculate the probability that each of 186 additional samples from coastal areas adjacent to suspected point sources of pollution may belong to each of the five sediment types. This analysis identified a sixth type of sediment dominating the area inside and near the entrance of Shuwaikh Port. Characterized by elevated levels of Ag, Cd, Cu, Hg, Pb and Zn, this type indicated the presence of a high level of metal pollution in the area.     

Early Diagenesis of Plant Pigments in Hudson River Sediments

Plant pigment concentrations were measured using high performance liquid chromatography in Hudson River sediments. Sedimentation rates and mixing characteristics were determined from depth profiles of the naturally occurring radionuclides ⁷Be, ²¹⁰Pb. Previous estimates of the mean-lives (1/λ) of plant pigments (chlorophylls a and b, fucoxanthin) from laboratory experiments, indicate a range of c. 20-40 days. However, in the field, we observed that these pigments decreased less rapidly with depth and penetrated deeper than ⁷Be (mean-life 77 days) in Hudson sediments 95% of the time. Assuming similar mixing processes for particles carrying ⁷Be and pigments, this indicates that pigment decay rates in the field are slower than the 0·013 day^-1 decay rate of ⁷Be, hence, more than 2-fold slower than the derived laboratory rates. We believe that high inputs of vascular plant detritus in the Hudson may increase the complexation of humic substances with pigments resulting in slower decay rates.While most pigments showed an exponential decrease with sediment depth, lutein concentrations generally increased with depth. This pattern of decay resistance is in agreement with laboratory experiments which show that lutein is the most decay resistant among dominant pigments. These data along with other studies demonstrate that the carotenoids lacking the 5,6-epoxide group (i.e., lutein) are more decay resistant than pigments that contain it (i.e., fucoxanthin).     

Radiotracer estimates of benthic activity effects on trace metal diffusion into mangrove sediments

Potential influences of the whole benthic organisms' activity (i.e., coupled faunal and microbial effects) on ⁵⁸Co, ⁵¹Cr and ⁶⁵Zn diffusion into surface mangrove sediment layers (0–6 cm depth) were evaluated in 36 h experiments. Benthic activity indices (BAI) were proposed, calculated as the relative percent difference between untreated sediments and formaldehyde-treated sediments data in relation to untreated sediments data. Benthic activity was estimated as responsible for 32%–44% of total inventories within sediments, being the chromate anion spiked the less affected radiotracer, while ⁶⁵Zn was the most sensitive. Benthic activity was quantitatively evidenced as a control on trace metal diffusion into the sediments, contributing to determine the sediment role as a metal sink. This influence can also affect metal potential bioavailability, considering that recently diffused metals can be more readily available to biological uptake.     

Effects of metals and sediment particle size on the species composition of the epifauna of Pinna bicolor near a lead smelter,Spencer Gulf,South Australia

Pinna bicolor (Mollusca: Pelecypoda) were transplanted between four sites near a lead smelter. The species composition of their epifauna (sessile and mobile) was examined in relation to characteristics of both sediments and seston at the sites. Seventy-two taxa were distinguished in the epifaunal community. Substantial differences were found in the short-term sensitivity of some of the species to concentrations of Cd, Pb and Zn in sediments and to sediment particle size. The short-term sensitivity of many species to metals or sediment particle size explained their long-term distribution pattern. Twenty-three taxa were identified as significantly characterizing the faunal differences. Of these, eleven (four molluscs, four bryozoans, two barnacles and one ascidian) were affected by both sediment metal concentration and particle size, and eight (four molluscs, one bryozoan, one polychaete, one hydroid and one barnacle) were affected by metal contamination but not particle size. Of all fauna examined, the Bryozoa were the most metal-sensitive. Four species, Smittina raigii (Bryozoa), Galeolaria sp. 1 (Polychaeta), Epopella simplex (Cirripedia) and Monia ione (Pelecypoda) were identified by their short- and long-term sensitivity to metal contamination, and absence of sensitivity to sediment particle size, as suitable species for monitoring the effects of metal contamination on the epifauna. The implications of the results for toxicity-testing are discussed.