Comparative sediment quality assessment in different littoral ecosystems from Spain (Gulf of Cadiz) and Brazil (Santos and São Vicente estuarine system)

The goal of this work was to establish comparisons among environmental degradation in different areas from Southern Spain (Gulf of Cádiz) and Brazil (Santos and S?o Vicente estuary), by using principal component analyses (PCA) to integrate sediment toxicity (amphipods mortality) and chemical-physical data (Zn, Cd, Pb, Cu, Ni, Co, V, PCBs, PAHs concentrations, OC and fines contents). The results of PCA extraction of Spanish data showed that Bay of Cádiz, CA-1 did not present contamination or degradation; CA-2 exhibited contamination by PCBs, however it was not related to the amphipods mortality. Ría of Huelva was the most impacted site, showing contamination caused principally by hydrocarbons, in HV-1 and HV-2, but heavy metals were also important contaminants at HV-1, HV-2 and HV-3. Algeciras Bay was considered as not degraded in GR-3 and -4, but in GR-3' high contamination by PAHs was found. In the Brazilian area, the most degraded sediments were found in the stations situated at the inner parts of the estuary (SSV-2, SSV-3, and SSV-4), followed by SSV-6, which is close to the Submarine Sewage Outfall of Santos - SSOS. Sediments from SSV-1 and SSV-5 did not present chemical contamination, organic contamination or significant amphipod mortality. The results of this investigation showed that both countries present environmental degradation related to PAHs: in Spain, at Ría of Huelva and Gudarranque river's estuary areas; and in Brasil, in the internal portion of the Santos and S?o Vicente estuary. The same situation is found for heavy metals, since all of the identified metals are related to toxicity in the studied areas, with few exceptions (V for both Brazil and Spain, and Cd and Co for Brazilian areas). The contamination by PCBs is more serious for Santos and S?o Vicente estuary than for the investigated areas in Gulf of Cádiz, where such compound did not relate to the toxicity.     

Geochemistry and bioavailability of metals in sediments from northern San Francisco Bay

In this study, metals (Be, Cr, Mn, Fe, Ni, Cu, Zn, Ag, Cd, Pb and Hg) in the fine-grained fraction (<63 microm) from 12 sites at different locations in northern San Francisco Bay over a year period from March 2000 to March 2001 were analyzed after acid extraction. The results showed that metal concentrations in the sediments varied from site to site, whereas some of them were found elevated with respect to the sediment of Tomales Bay, CA, which has little contamination history, indicating an enrichment of the metals in the sediment samples analyzed. Sediment toxicity and bioaccumulation evaluation by a clam species, Macoma nasuta, exposed to the sediment samples collected from the six sampling sites was carried out. The results showed that the sediment samples tested significantly reduced clam survival. Toxicity of the sediments to the clam was, in part, related to elevated metal concentrations in the sediments. In order to examine geochemistry of the metals and to understand potential correlations between metal concentrations and geochemical matrix elements of the sediments, bioavailability and toxicity of the metals, detailed analysis of metal concentrations associated with total organic carbon and the Fe-oxy-hydroxides in the sediment samples was performed. The analysis showed that sediment geochemistry appeared to influence metal bioavailability and may have important impacts on the toxicity of these metals to the clam.     

An assessment of toxicity in profundal lake sediment due to deposition of heavy metals and persistent organic pollutants from the atmosphere

A Tier I Sediment Ecological Risk Assessment of profundal lake sediment contaminated by diffuse pollution of heavy metals and POPs deposited from the atmosphere was completed. The concentrations of seven heavy metals and four groups of POPs (OCs, PCBs, PAHs, PBDEs) were determined in the profundal sediment of ten lakes in the United Kingdom and two sediment toxicity tests completed (chironomid survival and emergence and cladoceran survival and reproduction). The results showed that around half the lakes are at least moderately contaminated by Pb, Zn, Cd, As and PAHs deposited from the atmosphere and the toxicity quotient suggests that the contaminants of concern are Pb, As and PAHs, and not the other metals nor OCs and PCBs. There was toxicity in the sediment of four of the lakes. The Probable Effect Concentration Quotient values indicated that metals in the sediments of Scoat Tarn, Agden Reservoir and Llyn Llagi were likely to be responsible for the laboratory toxicity found in these lakes, with PAHs also contributing in Agden Reservoir.     

Novel approach for assessing heavy metal pollution and ecotoxicological status of rivers by means of passive sampling methods

In order to study the pollution of fluvial ecosystems, it is necessary to analyze not only the levels of chemical contaminants in water, but also those accumulated in the sediment matrix, as well as to assess its ecotoxicological status. Eleven Catalan (Spain) river sections (one sampling point per river) located near urban and industrial areas were sampled during winter of 2009. Water pollutants were collected by using passive samplers as Diffusive Gradient in Thin-Films (DGTs) and Semi-Permeable Membrane Devices (SPMDs). Point water samples were also collected. The concentrations of potentially toxic elements (PTE) in water, filtered water, DGTs and sediment samples were analyzed. Aqueous and organic solvent extracts of sediments samples and organic extracts of SPMDs were performed to assess acute toxicity to Vibrio fischeri by Microtox(?), and chronic toxicity to the green alga Pseudokirschneriella subcapitata. Microtox(?) test was also performed with DGT extracts. The results show that metals content of Catalan river waters are below the freshwater screening US EPA benchmarks, excepting some industrial areas (for Hg, Pb, and Zn). In contrast, sediments levels of some rivers were far above freshwater sediment screening US EPA benchmarks (for Zn, As, Cr, Pb, Ni, Hg, and Mn), particularly in the most industrialized areas. A good correlation was found between toxicity values of extracts (from sediments and DGTs) and PTE levels in sediments. The current results support the suitability of using combined point and passive sampling methods for assessing the chemical and ecotoxicological status of aqueous environments.     

Impact of dredging in a shallow coastal lagoon: Microtox Basic Solid-Phase Test, trace metals and Corophium bioassay

The aim of this work was to measure survival of the amphipod Corophium insidiosum and luminescence inhibition in the marine bacterium Vibrio fisheri on surface sediment samples collected from a shallow coastal lagoon (Pialassa Baiona, northern Adriatic Italian coast) before execution of dredging operations to deepen the main inner channel of the lagoon and restore the water circulation. Trace metal (Cd, Cu, Cr, Hg, Ni, Pb) concentrations, grain size and organic carbon matter content as loss of ignition were also measured. Toxicity testing with V. fisheri was carried out according to the Microtox Basic Solid-Phase Test (BSPT) protocol. The preliminary outcomes of this work show that: (a) the investigated area can be categorised as moderately degraded; (b) there is no evident spatial pattern in sediment toxicity and trace metal concentrations; (c) Microtox responses are not biased by sediment characteristics such as silt, clay and organic matter content.     

Correlation of field-measured toxicity with chemical concentration and pollutant availability.

Direct field toxicity tests were performed in two Louisiana waterways, Bayous Trepagnier and St. John, on sediments containing organic/heavy metal mixtures. Our approach involved bioluminescent bacterial toxicity assays (using DeltaTox, which qualitatively identifies polluted areas, and Microtox, which quantifies toxicity). Samples were more completely analyzed in our laboratory using inductively coupled plasma atomic emission spectroscopy (ICP-AES) and gas chromatography/mass spectrometry (GC/MS). Results indicate that lead is the primary toxic metal at the sites examined, though concentrations of metals fluctuate due to spatial variation and the dynamic nature of the waterways. Polycyclic aromatic hydrocarbons (PAHs) are the most abundant group of organics measured and appear to contribute to the overall toxic response. DeltaTox located toxic hotspots where there was an average light loss of 53-100%. Toxicity results from both assays agree but are well correlated with concentration measurements only for certain sediment fractions. Overall, the DeltaTox/Microtox approach appears to be rapid and cost effective for on-site hotspot identification, and may increase understanding of hazards associated with heavy metal and organic contaminants in these waterways.     

Physical resuspension and vertical mixing of sediments on a high energy continental margin (Sydney, Australia)

Four sediment cores from the continental margin adjacent to Sydney were analyzed for 210Pb, 137Cs, trace metals (Ag, Cd, Co, Cu, Mn, Ni, Pb, Zn), iron, dry bulk density, mud and moisture content. The concentrations of trace metals in the total sediment are low at all sites, although slightly elevated concentrations of Ag, Cu, Pb and Zn are present in the fine fraction of sediment (< 62.5 microns) near a major ocean outfall. Concentrations of trace metals in the fine fraction of sediment are similar in the upper 10-15 cm, indicating strong vertical mixing of the sediments, whereas an upward coarsening grain size in the upper 1-3 cm of sediment supports physical resuspension during storms. Sediment accumulation rates on the middle shelf adjacent to Sydney were estimated from downcore profiles of 210Pb and 137Cs and range between 0.2 and 0.4 cm yr-1. Although the mass fluxes of Cu, Pb and Zn within a distance of 2 km from the outfall (up to 36.1, 30.8 and 86.2 micrograms cm-2 yr-1, respectively) are greater than 20 km north of the outfall (< 23.5 micrograms cm-2 yr-1), the low concentrations of trace metals in sediments near the outfall support an efficient dispersal of anthropogenic contaminants on this continental margin.     

Composition, sources, and potential toxicological significance of PAHs in the surface sediments of the Meiliang Bay, Taihu Lake, China

Twenty-five surface sediment samples were collected from Meiliang Bay, Taihu Lake, China, in 2003. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), identified as priority pollutants by the USEPA, were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS). Total concentrations of the PAHs ranged from 1207 to 4754 ng/g dry weight. Sediment samples with the highest PAH concentrations were from the northern site of the bay, which is in proximity to the incoming PAH source; the PAH levels in the southern part were relatively low. The observed PAH levels were higher than those in river sediments in China but were lower than those found in sediments of urban areas and harbors. According to the observed molecular indices, PAHs originated largely from the high-temperature pyrolytic process, whereas the petrogenic process was more commonly responsible for PAH contamination in harbors. A good correlation existed between the benzo[a]pyrene level and the total PAH concentration (r=0.97), making benzo[a]pyrene a potential molecular marker for PAH pollution. According to the numerical effect-based sediment quality guideline (SQGs) of the United States, the levels of PAHs at most studied sites in Meiliang Bay, except some sites in the northern part of the bay, should not exert adverse biological effects. In the northern part of the bay, the PAH levels at sites 21 and 22 exceed the effects range low (ERL) and could thus cause acute biological impairments, in comparison with the sediment quality guidelines. The total PAH levels were expressed as the B[a]P toxicity equivalents (TEQs(carc)) and compared to the contaminated sediments from Guba Pechenga, Barents Sea, Russia.     

三峡库区香溪河库湾沉积物重金属污染特征

2010年3月在三峡水库香溪河库湾获取了无扰动沉积物柱状样,在香溪河口的长江干流(长江右岸)获取了表层沉积物样,现场进行了环境因子测量和室内粒度分析、矿物分析、重金属元素含量分析。沉积物矿物以绿泥石、伊利石和石英为主,占到全部矿物的65%左右。柱状沉积物pH值随深度增加呈现变小的趋势,Eh值也有随深度减少的趋势,反映了环境还原性加强。R-型因子分析结果表明:重金属元素的含量随粒径变细、绿泥石和伊利石含量增加而增加,而随石英、白云石含量增加而降低;且重金属元素含量变化与pH值密切相关,当pH值下降时部分重金属容易重新释放出来而进入环境中。库湾下游具有较中上游高得多的重金属含量,沉积物中重金属的污染程度为无污染到轻度污染,且轻度污染出现于下游至干流。三峡水库蓄水前香溪河沉积物中重金属含量顺序大致为Zn>Pb>Cu>As>Cd,而蓄水后香溪河及干流沉积物均表现为Cu含量高于Pb。     

应用平衡分配法建立长江水系沉积物金属相对质量基准

在不同的条件下,沉积物可成为环境中污染物的“源”或“汇”,而受污染的沉积物会对水生生物带来危害。因此,需要制定沉积物质量基准(SQC),以此作为评价沉积物污染及其生态效应的基础。在过去的几年中,对利用平衡分配法来建立SQC的方法进行了广泛的研究,并被认为是最有效的方法之一。采用平衡分配法,初步建立了长江水系8种重金属及类金属(Cu, Zn, Cd, Pb, Ni, Fe, Hg,As)的沉积物相对质量基准。结果表明,上述重金属及类金属的SQC在从长江上游到下游,总体趋势上呈降低的分布特征,并由于地域环境条件的不同,存在着高SQC值单元及低SQC值单元。得出的SQC与国内已有的SQC具有可比性,但高于美国国家环保局提出的SQC,主要是由于采用平衡分配法建立的SQC是一种数值型的基准值,缺乏生物效应的校正。因此,在将其应用到沉积物污染状况评价之前,还需要进行深入的研究工作,特别是毒理学试验。     

The pollution status and the toxicity of surface sediments in Izmit Bay (Marmara Sea), Turkey

Izmit Bay is one of the most polluted and populated enclosed sea in Turkey. It has been the centre of industrial activities for the last 30 years. Seven major sources enter the bay waters along the north coastline of the bay. This investigation forms part of continuing ecotoxicology studies in the Izmit Bay designed to constrain and minimise the pollution caused by flourishing industry and a growing population. Sediments sampled from the mouths of the major discharges of Izmit Bay were analysed for their organic carbon, total polycyclic aromatic hydrocarbon (t-PAH) and trace inorganic element (Cd, Al, As, Pb, Hg and Cu) contents and compared with those found in the sediments from the reference station in the outer bay (in the Marmara Sea). The toxicity of sediments was determined in the bulk and elutriate samples by using algal (Phaeodactylum tricornutum) batch bioassays. Chemical data showed that the sediments collected from the inner sites of the bay have been contaminated with Cd, Hg, As and PAHs. Organic carbon contents were also found higher. All the major industrial discharges into the bay are now biologically treated but bioassays performed with bulk sediments revealed that the recent sediments are toxic to the microalgae throughout the bay. The results are consistent with the previous toxicity studies performed with the industrial discharges.     

An integrated approach to the toxicity assessment of Irish marine sediments: validation of established marine bioassays for the monitoring of Irish marine sediments

This paper describes the ecotoxicological evaluation of marine sediments from three sites around Ireland representative of a range of contaminant burdens. A comprehensive assessment of potential sediment toxicity requires the consideration of multiple exposure phases. In addition to the evaluation of multi-exposure phases the use of a battery of multi-trophic test species has been advocated by a number of researchers as testing of single or few organisms may not detect toxicants with a specific mode of action. The Microtox(R) solid phase test (SPT) and the 10-d acute amphipod test with Corophium volutator were used to assess whole sediment toxicity. Porewater and elutriates were assessed with the Microtox(R) acute test, the marine prasinophyte Tetraselmis suecica, and the marine copepod Tisbe battagliai. Solvent extracts were assayed with the Microtox(R) and T. battagliai acute tests. Alexandra Basin was identified as the most toxic site according to all tests, except the Microtox(R) SPT which identified the Dunmore East site as being more toxic. However, it was not possible to correlate the observed ecotoxicological effects with a specific and/or class of contaminants based on sediment chemistry alone. Therefore porewaters found to elicit significant toxicity (Dunmore East and Alexandra Basin) with the test battery were selected for further TIE assessment with T. battalgiai and the Microtox(R) system. The results of this study have important implications for risk assessment in estuarine and coastal waters in Ireland, where, at present the monitoring of sediment and water quality is predominantly reliant on chemical analysis alone.     

Sediment quality in Rio Guadiamar (SW, Spain) after a tailing dam collapse: contamination, toxicity and bioavailability

An integrated assessment of sediment quality in the Guadiamar River after a mining spill was conducted. The concentration of different metals and other conventional parameters were measured in sediments located along the river. Four sediment toxicity tests (Hyalella azteca 28-day survival and growth test; Chironomus riparius 10-day survival and growth test; Hexagenia spp. 21-day survival and growth test; and Tubifex tubifex 28-day reproduction and survival test) were carried out to determine the effects associated with the accidental spill. The geochemical fractions of 6 metals (Fe, Mn, Zn, Cu, Pb, and Cd) were determined to establish the bioavailability of the metals. The relationship found in the concentrations of metals associated with the mobile fractions of the sediments in the sites studied is similar to the toxic mud from tailing pond and confirms that the toxic effects are associated with the metals Zn and Cd originating from the spill.     

Metal-contaminated soil remediation by using sludges of the marble industry: toxicological evaluation

The major risks due to metal pollution of sediments consist of leaching to groundwater and potential toxicity to animals and/or plants. The objective of this study was to evaluate by means of an ecotoxicological approach the effects of the addition of cutting marble sludges on the mobile metal fraction of sediments polluted with heavy metals. The study was carried out on two sediments derived from mining activities in Portman Bay (SE, Spain) polluted by heavy metals. These sediments were mixed with sludges left after the cutting of marble. The results obtained by leaching experiments showed that the addition of marble cutting sludge, consisting mainly of carbonates, to a heavy-metal polluted sediment produces a decrease of available metal forms. The carbonate content seems to play a role in chemical stabilisation of metals and in a decrease of toxicity of sediments. The leached solutions have a non-toxic effect. The mild remediation by addition of sludge has moreover effects to long term.     

背角无齿蚌(Anodonta woodiana)在五里湖中的重金属富集

通过对2003年2～3月采自五里湖水域代表样点的背角无齿蚌(Anodonta woodiana) 及用于对照的水样、底泥中重金属的测试,初步得出了Zn、Cu、Pb、As和Cd在这3类样本中的浓度范围。虽然水样中各重金属均未超过国家渔业水质标准（GB11607 89）,但底泥和背角无齿蚌的结果显示出Pb,特别是Zn、As的污染比较明显。背角无齿蚌作为生物指示物观察和评价该水域Zn、Cu、As、Pb、Cd的污染状况是可行的。结果反映该水域已不适用于渔业生产。作为食用贝类,其Pb、Cd,特别是Zn、As的残留有可能带来毒性影响。     

江苏天目湖表层沉积物中多环芳烃污染特征与来源

区别于长江三角洲地区众多的大型天然浅水湖泊，江苏天目湖是一个较深的水库型湖泊，也是重要的城乡生活及工农业水源地之一。为了解天目湖表层沉积物中多环芳烃（PAHs）污染状况， 2006年在天目湖全湖采集7个点位的表层沉积物样品，利用GC/MS分析了16种优控PAHs。结果表明：天目湖表层沉积物中16种优控PAHs总量介于28750~71393 ng/g（干重），平均值为45852 ng/g；在空间分布上，北部受污染程度高于南部，主要是北部旅游业快速发展导致污染物排放的影响；沉积物中总有机碳含量与PAHs总量呈显著相关；利用特征化合物指数对PAHs的来源进行判别，指示天目湖表层沉积物中PAHs的主要来源是木材、煤的不完全燃烧。与不同地区水体沉积物PAHs含量对比表明，天目湖PAHs污染处于一个低至中等程度。基于沉积物中多环芳烃的环境质量标准，仅有1个样点芴浓度超过风险效应低值，但远小于毒性风险效应中值，因此沉积物中多环芳烃的生态风险较小。然而天目湖表层沉积物中的PAHs的污染程度已超过南水北调东线所经过的南四湖，而且天目湖湖水较深，湖水交换周期比较长，其PAHs污染应引起重视，需制定切实措施保护江苏“最后一泓净水”。     

丹江口水库典型库湾及支流沉积物重金属污染分析及生态风险评价

对丹江口水库上游汉江支流及库湾沉积物中6种重金属元素的污染特征进行分析,采用效应阈值标准(NYSDEC)和Lars Hkanson潜在生态风险指数评价重金属的污染程度和环境风险。研究表明,库湾沉积物与支流沉积物中Ni、Pb含量较为接近;库湾沉积物中Cd、Cr、Cu、Zn含量分别高达186、2712、9991、4783 mg/kg,均超过支流沉积物中相应重金属含量2倍以上。各采样点表层（0~10 cm）沉积物中Pb含量均低于LEL值（最低效应阈值）,Cd、Ni含量均介于LEL值和SEL值（最高效应阈值）之间,而Cr、Cu、Zn含量均有超过SEL值的现象发生。考察沉积物重金属的富集程度发现各采样点表层沉积物中Ni和Pb均未发生富集,而Cd、Cr、Cu和Zn均存在不同程度的富集,其平均富集系数分别为712、180、163和284。根据重金属含量的相关性可知Ni和Pb主要来自于天然地球化学来源,而Cd、Cr、Cu和Zn则主要受人为源影响。以丹江口库区土壤（黄棕壤）中重金属背景值为参比,发现表层沉积物总体处于高生态风险,且以Cd生态风险为主;参与评价的5种重金属潜在生态风险程度顺序为Cd＞Cu＞Cr＞Zn＞Pb     

The use of a metallothionein-like-proteins (MTLP) kinetic approach for metal bioavailability monitoring in dredged material

Ecotoxicological effects associated with contaminants present in dredged material from Spain were determined using a marine biotest based on the determination of metallothionein-like-protein concentrations (MTLPs) in the shore crab Carcinus maenas. Intermoult female C. maenas were exposed in the laboratory to sediments from three Spanish ports, Ría de Huelva (SW, Spain), La Coru?a (NW, Spain) and Bahía de Cádiz (SW, Spain) per replicate during 21 days. Hepatopancreas samples from crabs were taken for metallothioneins analysis on days 0, 7 and 21. Furthermore, chemical analysis was performed in the stations to determine the degree and nature of sediment contamination (Cr, Ni, Cu, Zn, Cd, Pb, Hg, As, PAHs and PCBs). A significant increase (p<0.05) in metallothionein concentration was observed over time in individuals exposed to sediment from the port Ría de Huelva characterized by high concentrations of metals. A toxicokinetic approach is proposed in this study related to the use of this biomarker in C. maenas to evaluate bioavailability associated with metals present in dredged material. As a first step, this toxicokinetic approach might reveal as a sensitive tool for evaluating bioavailability of contaminants present in dredged material.     

长江口潮滩沉积物中活性重金属的空间分异及控制机制

利用盐酸羟氨-25%醋酸溶液，提取了长江口潮滩沉积物中活性重金属含量。研究发现，长江口潮滩沉积物中活性重金属占总量的百分含量依次为Cu 26%，Pb 36%，Fe 7%，Mn 49%，Zn 32%，Cr 14%和Al 16%，沉积物基本未受到Cr污染，其余重金属污染程度处于中等偏下水平。除Zn、Cr外，其余活性重金属在夏季沉积物中的含量明显低于春季，其主要原因是夏季风暴潮将大量细颗粒泥沙及其富集的重金属带离潮滩进入了河口水体中。受点源污染排放及沉积物粒度影响，活性重金属在长江口南岸的浒浦、顾路和浦东机场出现峰值含量，且高潮滩含量明显高于中、低潮滩。在垂向上，重金属一般在沉积物表层或亚表层形成富集。在口门附近的滨岸潮滩沉积物中，Cu、Pb的空间分异主要受早期成岩作用的控制，在污染较为严重、水动力作用相对较弱的潮滩沉积物中，Cu、Pb的空间分异主要受沉积物中有机质含量变化的控制.