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1.
Elutriate embryo-larval bioassays with sea-urchins (Paracentrotus lividus) were conducted concurrently with chemical analyses of sediments and biota as part of an integrative assessment of pollution in highly productive coastal regions. High metal contents and organic compounds in sediments and mussels were found in localised areas from the inner part of the estuaries indicating a clear anthropogenic influence. In particular, average maximum concentrations of 2803 mg Cu/kg dw, 776 mg Pb/kg dw, 2.5 mg Hg/kg dw and 5803 μg ∑7PAHs/kg dw were measured in sediments from the most polluted sites. Significant correlations were observed between sediment chemistry and toxicity bioassays. Moreover, the Mantel test revealed a significant correlation (rM=0.80; p<0.01) between sediment pollutant concentrations and toxicity data profiles. In addition, sediment quality criteria were used to help in the ecological interpretation of sediment chemistry data and to identify pollutants of concern. The toxicity bioassays identified polluted sites and quantified the level of toxicity, providing a cost-effective tool to complement the routine chemical monitoring currently conducted in European coastal waters with ecologically relevant information. This is in line with the recent European legislation that advocates the use of biological tools with the ultimate aim of protecting marine resources from anthropogenic substances that will affect their sensitive early life stages.  相似文献   

2.
Sediment from harbors of the Emilia-Romagna (Northern Adriatic Sea) were dredged and dumped in four disposal areas characterized by muddy bottoms. The long-term effects of the dumping on macrozoobenthic communities were investigated before and after 6 month, 8 month, 2 years and 4 years. The disposal of dredged material did not influence the granulometry and %TOC in the sediment, and no alterations in the structure of the macrobenthic communities were observed in the four areas. The lack of impact could be ascribed to the environmental characteristics and precautionary measures taken to minimize the effects of the dumping. It appears that: (1) the communities of the dumping areas are well adapted to unstable environments; (2) the sediments were disposed gradually and homogeneously over relatively large areas; Other factors that help to reduce the impact of sediment disposal are the low concentrations of contaminants in dredged materials and the similarity of sediment in the dredged and disposal areas. Off-shore discharge appears a sustainable strategy for the management of uncontaminated dredged sediments from the Northern Adriatic Sea harbors.  相似文献   

3.
Copper-based antifoulant paints and the sea lice treatment Slice® are widely used, and often detectable in the sediments beneath farms where they are administered. Ten-day, whole sediment mesocosm experiments were conducted to examine how increasing sediment concentrations of copper or Slice® influenced final water column concentrations of ammonium-nitrogen (NH4-N), nitrate + nitrite-nitrogen (NOX-N) and phosphate-phosphorus (PO4-P) in the presence of the non-target, benthic organisms Corophium volutator and Hediste diversicolor. Nominal sediment concentrations of copper and Slice® had significant effects on the resulting concentrations of almost all nutrients examined. The overall trends in nutrient concentrations at the end of the 10-day incubations were highly similar between the trials with either copper or Slice®, irrespective of the invertebrate species present. This suggests that nutrient exchange from the experimental sediments was primarily influenced by the direct effect of copper/Slice® dose on the sediment microbial community, rather than the indirect effect of reduced bioturbation/irrigation due to increased macrofaunal mortality.  相似文献   

4.
A large number and variety of species of actinomycetes were isolated from sediment samples collected in New York Harbour and from the New York Bight in the course of studies on the distribution of these bacteria in coastal regions. Isolates recovered from the New York Bight sediment were similar to those from other inshore areas, although the total counts were lower. Larger numbers of actinomycetes were recovered from harbour sediments, as well as dredging spoil samples collected from a capped dump site in the New York Bight. The capping operation was monitored and effects on the microbial populations were detected. Selected genera associated with the dredge spoil were determined to be allochthonous, providing useful microbial markers for the dredged material. Many of the microbial species survive in the dump area, but some appear to be metabolically active, perhaps altering the chemical nature of the dumped material.  相似文献   

5.
Juvenile Senegalese soles were exposed through 28-day laboratory and field (in situ) bioassays to sediments from three sites of the Sado estuary (W Portugal): a reference and two contaminated by metallic and organic contaminants. Fish were surveyed for ten hepatic histopathological alterations divided by four distinct reaction patterns and integrated through the estimation of individual histopathological condition indices. Fish exposed to contaminated sediments sustained more damage, with especial respect to regressive changes like necrosis. However, differences were observed between laboratory- and field-exposed animals, with the latest, for instance, exhibiting more pronounced fatty degeneration and hepatocellular eosinophilic alteration. Also, some lesions in fish exposed to the reference sediment indicate that in both assays unaccounted variables produced experimental background noise, such as hyaline degeneration in laboratory-exposed fish. Still, the field assays yielded results that were found to better reflect the overall levels of contaminants and physico-chemical characteristics of the tested sediments.  相似文献   

6.
The change in community diversity and structure of the indigenous, dominant, polycyclic aromatic hydrocarbon (PAH)-degrading bacterial genera, Sphingomonas and Mycobacterium, due to contamination in the environment is not very well known. A combination of PCR-DGGE with specific primers and a cultivation-dependent microbiological method was used to detect different populations of Sphingomonas and Mycobacterium in mangrove sediments. The structure of the entire bacterial community (including Sphingomonas) did not show a shift due to environmental contamination, whereas the diversity of Mycobacterium populations in mangrove sediments with higher PAH contamination increased from exposure between Day 0 and Day 30. The isolated Mycobacterium strains migrated to the same position as the major bands of the bacterial communities in Mycobacterium-specific DGGE. A dioxygenase gene system, nidA, which is commonly found in PAH-degrading Mycobacterium strains, was also detected in the more highly contaminated sediment slurries. The present study revealed that Mycobacterium species were the dominant PAH-degraders and played an important role in degrading PAHs in contaminated mangrove sediments.  相似文献   

7.
《Marine pollution bulletin》2013,71(1-2):204-209
The potential toxicity of sediments from various ports was assessed by means of two different liquid-phase toxicity bioassays (acute and chronic) with embryos and eggs of sea urchin Paracentrotus lividus. Performances of embryos and eggs of P. lividus in these bioassays were compared for their interchangeable applicability in integrated sediment quality assessment. The obtained endpoints (percentages of normally developed plutei and fertilized eggs) were linked to physical and chemical properties of sediments and demonstrated dependence on sediment contamination. The endpoints in the two bioassays were strongly correlated and generally exhibited similar tendency throughout the samples. Therein, embryos demonstrated higher sensitivity to elutriate exposure, compared to eggs. It was concluded that these tests could be used interchangeably for testing toxicity of marine sediments. Preferential use of any of the bioassays can be determined by the discriminatory capacity of the test or vulnerability consideration of the test subject to the surrounding conditions.  相似文献   

8.
In the joint estuary of the Odiel and Tinto rivers (SW Spain), the invasive Spartina densiflora Brongn. and the native Spartina maritima (Curtis) Fernald are growing over sediments with extreme concentrations of heavy metals. The contents of As, Cu, Fe, Mn, Pb and Zn were determined in sediments, rhizosediments and different tissues of both species, from Odiel and Tinto marshes. S. densiflora showed a higher capability to retain metals around their roots and to control the uptake or transport of metals, mediated by a higher formation of plaques of Fe/Mn (hydro) oxides on the roots. At the Tinto marsh, there were no differences between the metal concentrations of the sediment and those of the rhizosediment, a fact that could be explained by the extremely high concentrations of metals which can pass over a threshold value, altering the properties of root cells and preventing roots from acting as a ‘barrier’ to the uptake or transport of metals.  相似文献   

9.
From 1999 to 2005, studies carried out in the frame of regional and national French programs aimed to determine whether the Phaeocystisglobosa bloom affected the intertidal benthic communities of the French coast of the eastern English Channel in terms of composition and/or functioning. Study sites were chosen to cover most of the typical shore types encountered on this coast (a rocky shore, an exposed sandy beach and a small estuary). Both the presence of active Phaeocystis cells and their degradation product (foam) did have a significant impact on the studied shores. The primary production and growth rates of the kelp Saccharina latissima decreased during the bloom because of a shortage of light and nutrient for the macroalgae. On sandy sediments, the benthic metabolism (community respiration and community primary production), as well as the nitrification rate, were enhanced during foam deposits, in relation with the presence of bacteria and active pelagic cells within the decaying colonies. In estuarine sediments, the most impressive impact was the formation of a crust at the sediment surface due to drying foam. This led to anoxic conditions in the surface sediment and resulted in a high mortality among the benthic community. Some organisms also tended to migrate upward and were then directly accessible to the higher trophic level represented by birds. Phaeocystis then created a shortcut in the estuarine trophic network. Most of these modifications lasted shortly and all the systems considered came back to their regular properties and activities a few weeks after the end of the bloom, except for the most impacted estuarine area.  相似文献   

10.
Deposit-feeding holothurians are important processors of surface sediments in many coastal marine systems. The present study examined the effect of grazing by the sea cucumber Australostichopus mollis on sediment impacted by green-lipped mussel biodeposits (faeces and pseudofaeces) from coastal aquaculture activities. Grazing effects were investigated in a series of tank-based feeding experiments conducted over 1, 2, 4 and 8 week periods. Sediment quality indicators routinely applied to determine the impacts of coastal aquaculture were used to evaluate sediment health from grazed and ungrazed sediments. Sea cucumber grazing resulted in reductions in total organic carbon, chlorophyll a and phaeopigment, as well as chlorophyll a/phaeopigment ratio of impacted sediments. These results demonstrate that sea cucumber grazing significantly reduces the accumulation of both organic carbon and phytopigments associated with biodeposition from mussel farms. Sea cucumber grazing offers a means of constraining or reversing the pollutive impacts of coastal bivalve aquaculture.  相似文献   

11.
The concentration and areal distribution of selected trace metals (Cu, Zn, Pb, Cd, Mo, Ni, Mn and Hg) in surficial sediments of Saint John Harbour, New Brunswick, Canada, were studied to determine the extent of anthropogenic input and to estimate the effects of dumping dredged material in the outer harbour. Hg and Cd are of especial concern, since the disposal of dredge material containing these two elements is regulated under the Ocean Dumping Control Act.The concentrations of all metals are low: Cu 16, Zn 53, Pb 24, Cd 0.16, Mo 3, Ni 16, Mn 296 and Hg 0.04 μg g?1. Hg and Cd levels in sediments are well below the permissible limits of 0.75 and 0.6 μg g?1, respectively, set by the Ocean Dumping Control Act.The mean concentrations of trace elements are similar to the low mean values in the unpolluted Bay of Fundy. There is an overall decline in concentrations of metals in the sediments from the inner to the outer harbour. Comparison of the metal levels in the sediments from different areas within the harbour indicate that there is a detectable anthropogenic input in the Courtenay Bay area. Trace metal levels at the dumpsite are significantly lower than in the Courtenay Bay area, where the bulk of the dredged material originates.  相似文献   

12.
The influence of seasonal and environmental parameters on the occurrence of bacteria was investigated in two clam species (Venerupis pullastra and Ruditapes philippinarum), water and sediment from the Tagus estuary. Total viable counts (TVC), Escherichia coli, Salmonella spp. and Vibrio spp. were evaluated during one-year. Overall, significant seasonal variations were found in both sampling sites, especially for E. coli and Vibrio spp. levels. In summer, significantly higher Vibrio spp. levels were found in R. philippinarum and sediment samples, but not in V. pullastra clams and water samples. In contrast, significantly higher TVC and E. coli levels were observed in winter months in water and sediment samples. Salmonella spp. was generally isolated when higher levels of E. coli were detected, particularly in R. philippinarum. This study is useful for authorities to develop monitoring strategies for coastal contamination and to estimate human health risks associated with the consumption of bivalves.  相似文献   

13.
The impact of dead discards, originating from beam trawl fishing on the nematode community from the Tagus estuary was investigated in terms of vertical distribution of the dominant nematode groups. Sediment cores were collected from a mud-flat from the Tagus estuary. Crangoncrangon (Linnaeus, 1758) carcasses were added to the surface of the cores, simulating the settling of dead discards on the sediment. The vertical distribution of the dominant nematode groups was determined up to 4 cm deep at four different moments in time post deposition (0, 2, 4 and 6 h) and compared to control cores. The C.crangon addition to the sediment led to the formation of black spots and therefore oxygen depleted areas at the sediment surface. The Chromadora/Ptycholaimellus group, normally dominant at the surface layer, migrated downwards due to their high sensibility to toxic conditions. Sabatieria presented the opposite trend and became the dominant group at the surface layer. Since Sabatieria is tolerant to oxygen stressed conditions and high sulphide concentrations, we suggest that it migrated opportunistically towards an unoccupied niche. Daptonema, Metachromadora and Terschellingia did not show any vertical migration, reflecting their tolerance to anoxic and high sulphidic conditions. Our study showed that an accumulation of dead discards at the sediment surface might therefore alter the nematode community vertical distribution. This effect is apparently closely related to toxic conditions in the sediment, induced by the deposition of C.crangon at the sediment surface. These alterations might be temporal and reflect an adaptation of the nematode community to dynamic intertidal environments.  相似文献   

14.
Programs for evaluating proposed discharges of dredged material into waters of the United States specify a tiered testing and evaluation protocol that includes performance of acute and chronic bioassays to assess toxicity of the dredged sediments. Although these evaluations reflect the toxicological risks associated with disposal activities to some degree, analysis activities are limited to the sediments of each dredging project separately. Cumulative risks to water column and benthic organisms at and near the designated disposal site are therefore difficult to assess. An alternate approach is to focus attention on the disposal site, with the goal of understanding more directly the risks of multiple disposal events to receiving ecosystems. Here we review current US toxicity testing and evaluation protocols, and describe an application of ecological risk assessment that allows consideration of the temporal and spatial components of risk to receiving aquatic ecosystems. When expanded to include other disposal options, this approach can provide the basis for holistic management of dredged material disposal.  相似文献   

15.
In a dispersive coastal area under multiple organic enrichment sources, stable isotopes were used to trace organic sources of carbon and nitrogen in sediments and benthic macrofauna. The Bivalve Abra alba and the Polychaetes Nephtys sp. and Pectinaria (Lagis) koreni were reliable indicators of the input of terrestrial-derived organic matter into this coastal area, either originated in outfall sewage discharges or estuarine outflow. An isotopic depletion was observed up to 250 m from the outfall branches, much stronger in the biota than in the sediments. An enrichment of 2‰ in the sediments, and 2-6‰ in the species was noticed in sites located farther than 1500 m from the outfall. Depositivores and carnivores/omnivores gave the best picture of the extension of the sewage dispersion and incorporation into the food web.  相似文献   

16.
We present a method to estimate the spatial distribution of dredged material disposed of at sea. Using both dredged sediments and samples of sea-bed sediment from near the Rame Head disposal site, Plymouth, UK, we applied entropy analysis to the <63 μm sediment fraction and combined the results with the trace metal data in the same fraction, to form a series of groups. We interpret the distribution of sediments in one group (F1) to approximate the distribution of material affected by the disposal site. This distribution includes locations close to the disposal site, and also locations <4 km to the SE and SW, <6 km to the NW and <2 km to the N. This approach demonstrates the feasibility of using trace metal analysis of particular grain size fractions to reduce uncertainty in interpreting the spatial distribution of impacts of dredge disposal.  相似文献   

17.
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   

18.
In December 1999, 28,000 m3 of sediment was dredged from two sites within the harbour at Coffs Harbour, NSW. Dredging was carried out using a trailing suction hopper-dredge which transported the spoil to a shallow (6 m) site within the adjacent Solitary Islands Marine Park for disposal. Evaluation of the effects of the dredge-spoil dumping at the receiving site was conducted by taking replicated van Veen grab samples at the disposal site and at two control sites, before, immediately after, and three months after dumping. The results indicated that dredge-spoil dumping had no detectable effect on either the structure of the invertebrate community or the physical characteristics of sediment at the receiving site. Although there were some significant faunistic differences between samples from the disposal site and the control sites immediately following dumping, these were related to pre-existing differences between sites rather than to the effects of dredge-spoil disposal. Four principal factors are likely to have contributed to the lack of impact: (i) dredged material had similar sedimentary characteristics to those at the receiving site; (ii) dredged material was free from contaminants; (iii) the disposal method systematically distributed a number of shallow layers of sediment over the disposal site and thus motile macrofauna had the opportunity to migrate upwards between passes of the barge; and (iv) the disposal site was in a high energy environment where the resident biota are likely to be adapted to dynamic sedimentary conditions. The lack of detectable effects suggests that the disposal strategy was one which minimized impacts within an area which has high conservation value and should thus be adopted as a model for future works within the region.  相似文献   

19.
Molluscan shell debris is an under-exploited means of detecting, sourcing, and age-dating dredged sediments in open-shelf settings. Backscatter features on the Southern California shelf are suggestive of dredged sediment hauled from San Diego Bay but deposited significantly inshore of the EPA-designated ocean disposal site. We find that 36% of all identifiable bivalve shells > 2 mm (44% of shells > 4 mm) in sediment samples from this 'short dump' area are from species known to live exclusively in the Bay; such shells are absent at reference sites of comparable water depth, indicating that their presence in the short-dump area signals non-compliant disposal rather than natural offshore transport or sea level rise. These sediments lack the shells of species that invaded California bays in the 1970s, suggesting that disposal preceded federal regulations. This inexpensive, low-tech method, with its protocol for rejecting alternative hypotheses, will be easy to adapt in other settings.  相似文献   

20.
湖泊底泥疏浚环境效应:Ⅲ.对沉积物反硝化作用的影响   总被引：8，自引：1，他引：7  
通过为期一年的疏浚模拟试验,在试验室培养疏浚与对照柱样,研究了底泥疏浚对沉积物反硝化过程的影响.沉积物反硝化速率的测定采用经典的乙炔抑制法.研究结果表明,在一年的试验周期内,疏浚和对照柱沉积物的反硝化速率分别为6.9-26.9nmol/(g·h)和21.6-102.7nmol/(g·h),除2006年的2月外的其他月份,疏浚沉积物的反硝化速率显著(P<0.05)低于未疏浚对照沉积物,同时还研究了环境因子对沉积物反硝化速率的影响,结果表明,疏浚和对照沉积物的反硝化速率都受温度的控制.硝态氟浓度是疏浚和对照沉积物反硝化速率的主要限制因子,有机碳对疏浚沉积物的反硝化速率有影响,但对未疏浚对照沉积物的反硝化速率没有影响.疏浚后短期内沉积物反硝化速率低于未疏浚对照沉积物,可看作是底泥疏浚在富营养华水体脱氮方面的一个负效应.  相似文献   

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