洪泽湖溧河洼水生植物体内重金属调查

对洪泽湖溧河洼区域的水生植物进行了Cu、Zn、Pb、Cr和Cd等重金属元素的污染调查与监测分析,结果表明:水生植物对重金属元素的吸收与积累反映了环境中的重金属污染水平,不同水生植物对各种重金属元素的吸收富集状况具有相对一致性,即Zn>Cu>Cr>Pb>Cd。水生植物对各种重金属元素的平均富集系数大小顺序为:Cd>Cu>Zn>Cr>Pb,这与各元素迁移性强弱的顺序也是相一致的,Cd、Cu、Zn等各元素较易为植物所吸收,而Pb的移动性较差。大部分水生植物根部的重金属含量比茎叶部分高。研究表明:可以从中筛选出具有高富集作用的植物,作为修复水体或土壤重金属污染的实验植物,为植物修复作用的研究提供参考。     

Pollution, fractionation, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils from a Pb/Zn mining area

This study was conducted to investigate the pollution load index, fraction distributions, and mobility of Pb, Cd, Cu, and Zn in garden and paddy soils collected from a Pb/Zn mine in Chenzhou City, China. The samples were analyzed using Leleyter and Probst’s sequential extraction procedures. Total metal concentrations including Pb, Cd, Cu, and Zn exceeded the maximum permissible limits for soils set by the Ministry of Environmental Protection of China, and the order of the pollution index was Cd > Zn > Pb > Cu, indicating that the soils from both sites seriously suffered from heavy metal pollution, especially Cd. The sums of metal fractions were in agreement with the total contents of heavy metals. However, there were significant differences in fraction distributions of heavy metals in garden and paddy soils. The residual fractions of heavy metals were the predominant form with 43.0% for Pb, 32.3% for Cd, 33.5% for Cu, and 44.2% for Zn in garden soil, while 51.6% for Pb, 40.4% for Cd, 40.3% for Cu, and 40.9% for Zn in paddy soil. Furthermore, the proportions of water-soluble and exchangeable fractions extracted by the selected analytical methods were the lowest among all fractions. On the basis of the speciation of heavy metals, the mobility factor values of heavy metals have the following order: Cd (25.2–19.8%) > Cu (22.6–6.3%) > Zn (9.6–6.0%) > Pb (6.7–2.5%) in both contaminated soils.     

Heavy metal contamination in a vulnerable mangrove swamp in South China

Concentrations of six heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavy metals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavy metals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavy metals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavy metals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavy metals after its propagule stage for its regeneration and growth to be significantly affected by heavy metal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavy metals in an ecosystem.     

Heavy metal contamination in soil alongside mountain railway in Sichuan, China

Heavy metal concentration in soil was investigated at three sites with different topography (cut slope, flat and embankment) within the vicinity of Chengdu-Kunming railway in Sichuan, China. Surface soil was sampled at certain distances from the track at each site and was analyzed for Cu, Mn, Pb, Zn, Cd by atomic absorption spectrometry. Cu, Cd and Zn concentrations in some soil exceeded the thresholds for non-polluted soil following the soil quality standard set by the State Environmental Protection Agency of China. Compared to local background values, the highest enrichment factor values of Cu, Mn, Zn and Cd were 2.7, 3.4, 3.7 and 7.7, respectively, indicating a moderate or significant enrichment of these metals in soil closest to the railway. Pb showed little accumulation with the EF values generally nearer 1 at the chosen sites. Topography profile was found to influence metal levels and distribution in soil alongside railway. At the cut slope site, Mn, Zn, Cd showed the highest concentrations and the smallest dispersion distance of 2 m, while Cu showed further dispersion distance of 25 m due to a main Cu emission source, the head-over traction cable, being located higher than any other metal emission source (wheels and tracks). Heavy metal concentrations decreased conversely as compared to distance from the track, peak values occurring at locations closest to the tracks, whilst embankment site soil Cd concentrations peaked at distances of 25 m. Significant correlation was found amongst Mn, Cu, Zn and Cd, which indicates that these metals have the same anthropogenic origin there. Organic matter content had no significant correlation to the elements Mn, Cu and Zn, which implies relatively high mobility to those metals.     

Levels and speciation of heavy metals in soils of industrial Southern Nigeria

A knowledge of the total content of trace metals is not enoughto fully assess the environmental impact of polluted soils. Forthis reason, the determination of metal species in solution isimportant to evaluate their behaviour in the environment andtheir mobilization capacity. Sequential extraction procedure wasused to speciate five heavy metals (Cd, Pb, Cu, Ni and Zn) fromfour contaminated soils of Southern Nigeria into sixoperationally defined geochemical species: water soluble,enchangeable, carbonates, Fe-Mn oxide, organic and residual.Metal recoveries were within ± 10% of the independentlydetermined total Cd, Pb, Cu, Ni and Zn concentrations. The highest amount of Cd (avg. 30%) in the nonresidual fractionswas found in the exchangeable fraction, while Cu and Zn weresignificantly associated with the organic fraction. Thecarbonate fraction contained on average 14, 18.6, 12.6, 13 and11% and the residual fraction contained on average 47, 18, 33,50 and 25% of Cd, Pb, Cu, Ni and Zn respectively. Assuming thatmobility and bioavailability of these metals are related to thesolubility of the geochemical form of the metals, and that theydecrease in the order of extraction sequence, the apparentmobility and potential bioavailability for these five metals inthe soil were: Pb > Zn > Cu > Ni > Cd. The mobility indexes ofcopper and nickel correlated positively and significantly withthe total content of metals, while mobility indexes of cadmiumand zinc correlated negatively and significantly with the totalcontent of metals.     

Distribution,bioavailability, and potential ecological risk of Cu,Pb, and Zn in soil in a potential groundwater source area

In this study, we examined three horizontal and vertical soil profiles along a sewage drainage ditch in order to determine the spatial distribution of Cu, Pb, and Zn in soils and to assess the bioavailability and potential ecological risks associated with these metals in a potential groundwater source area. Results showed that the concentrations of Cu, Pb, and Zn were approximately at background level, suggesting that human activities (industrial and agricultural pollution) had a negligible influence on these metals in soil, and that the concentrations reflected the natural background levels in the study area. Cu, Pb, and Zn concentrations were slightly higher in topsoil (0–20 cm) than deeper in the soil profile. Using a modified BCR sequential extraction method to evaluate the mobility and bioavailability of metals showed that the potential bioavailability sequence of Cu, Pb, and Zn at three depths in the soil profile was in the order Cu?≈?Pb?<?Zn. The potential ecological risk from the metals was evaluated using risk assessment code, and the results suggest that Cu and Zn pose no or low risk, while there is a low or medium risk from Pb. Results from groundwater monitoring showed that the groundwater was not polluted by leaching from soil.     

Pollution in the urban soils of Lianyungang,China, evaluated using a pollution index,mobility of heavy metals,and enzymatic activities

Soil samples from 16 urban sites in Lianyungang, China were collected and analyzed. A pollution index was used to assess the potential ecological risk of heavy metals and a sequential extraction procedure was used to evaluate the relative distribution of Cu, Zn, Pb, Cd, Cr, and As in exchangeable, carbonate, Fe/Mn oxide, organic/sulfide, and residual fractions. The mobility of heavy metals and urease (URE) activity, alkaline phosphatase (ALP) activity, and invertase (INV) activity of soils was determined. The results showed that the average concentrations of Cu, Zn, Pb, Cd, Cr, and As in Lianyungang soils were much higher than those in the coastal city soil background values of Jiangsu and China. Among the five studied regions (utilities, commercial, industrial, tourism, and roadside), the industrial region had the highest metal concentrations demonstrating that land use had a significant impact on the accumulation of heavy metals in Lianyungang soils. Compared to the other metals, Cd showed the highest ecological risk. According to chemical partitioning, Cu was associated with the organic/sulfides and Pb and Zn were mainly in the carbonate and the Fe/Mn oxide phase. The greatest amounts of Cd were found in exchangeable and carbonate fractions, while Cr and As were mainly in the residual fraction. Cd had the highest mobility of all metals, and the order of mobility (highest to lowest) of heavy metals in Lianyungang soils was Cd > Zn > Pb > Cu > As > Cr. Soil urease activity, alkaline phosphatase activity, and invertase activity varied considerably in different pollution degree sites. Soil enzyme activities had the lowest levels in roadside and industrial regions. Across all the soil data in the five regions, the total Cu, Zn, Pb, Cd, Cr, and As level was negatively correlated with urease activity, alkaline phosphatase activity, and invertase activity, but the relationship was not significant. In the industrial region, alkaline phosphatase activity had significant negative correlations with total Cu, Pb, Cr, Zn, Cd, and heavy metal fractions. This showed that alkaline phosphatase activity was sensitive to heavy metals in heavily contaminated regions, whereas urease and invertase were less affected. The combination of the various methods may offer a powerful analytical technique in the study of heavy metal pollution in street soil.     

Contribution to biomonitoring of some trace metals by deciduous tree leaves in urban areas

Leaves of the deciduous tree species, horse chestnut (Aesculus hippocastanum L.) and Turkish hazel (Corylus colurna L.) were used as accumulative biomonitors of trace metal pollution in the urban area of Belgrade. Using differential pulse anodic stripping voltametry, trace metal concentrations (Pb, Cu, Zn, Cd) were determined at the single leaf level (ten leaves per species, per month), during two successive years with markedly different atmospheric level of trace metals. Increased trace metal concentrations in the leaves of A. hippocastanum reflected elevated atmospheric trace metal pollution, whereas C. colurna L. did not respond accordingly. The contents of Pb and Zn in soil over the same period also followed this trend. Anatomical analyses, in young as well as in old leaves of both species, indicated typical foliar injuries of plants exposed to stressful air conditions. Water relations that correspond to leaf age may have contributed to the considerable trace metal accumulation in leaves.     

Environmental variation between habitats and uptake of heavy metals by Urtica dioica

The observation from previous surveys, that Urtica dioica plants that had grown in metal contaminated soil in the floodplains of the former Rhine estuary in different habitats, but at comparable total soil metal concentrations, showed significant differences in tissue metal concentrations, led to the hypothesis that variation in other environmental characteristics than soil composition and chemical speciation of metals between habitats is also important in determining uptake and translocation of metals in plants. A field survey indicated that differences in root Cd, Cu and Zn concentrations might partly be explained by variation in speciation of metals in different habitats. However, shoot concentrations showed a different pattern that did not relate to variation in soil metal concentrations. In a habitat experiment Urtica dioica plants were grown in artificially contaminated soil in pots that were placed in the four habitats (grassland, pure reed, mixed reed, osier bed) that were also included in the field survey. After seven weeks the plants showed significant differences in Cu and Zn concentrations in roots and aboveground plant parts and in distribution of the metals in the plants between habitats. It was concluded that variation between habitats in environmental characteristics other than soil composition can explain as much variation in plants as can variation in soil metal concentrations and/or speciation. The implications for assessment of soil metal contamination and uptake by plants are discussed.     

Mobility of selected trace elements in Mediterranean red soil amended with phosphogypsum: experimental study

Soil amendment by phosphogypsum (PG) application becomes of increasing importance in agriculture. This may lead, however, to soil, plant, and groundwater contamination with trace elements (TEs) inherently present in PG. Monitoring of selected TEs (Pb, Zn, Cu, and Cd) distribution and mobility in a Mediterranean red soil profile has been performed in soil parcels applied with PG over a 16-month period. Concentrations were measured in soil and plant samples collected from various depth intervals at different points in time. TEs sequential extraction was performed on soil and PG samples. Results showed soil profile enrichment peaked 5 months after PG application for Cd, and 12 months for Pb, Zn, and Cu. Rainwater, pH, total organic carbon, and cationic exchange capacity were the main controlling factors in TEs accumulation in soils. Cd was transferred to a soil depth of about 20 cm. Zn exhibited mobility towards deeper layers. Pb and Cu were accumulated in around 20-55-cm-deep layers. PG increased the solubility of the studied TEs; PG-applied soils contained TEs bound to exchangeable and acid-soluble fractions in higher percentages than reference soil. Pb, Zn, and Cu were sorbed into mineral soil phases, while Cd was mainly found in the exchangeable (bio-available) form. The order of TEs decreasing mobility was Zn > Cd > Pb > Cu. Roots and leaves of existed plants, Cichorium intybus L., accumulated high concentrations of Cd (1-2.4 mg/kg), exceeding recommended tolerable levels, and thus signifying potential health threats through contaminated crops. It was therefore recommended that PG should be applied in carefully established, monitored, and controlled quantities to agricultural soils.     

Trace metal (Cd,Cu, Pb,Zn) fractionation in urban-industrial soils of Ust-Kamenogorsk (Oskemen), Kazakhstan—implications for the assessment of environmental quality

Ust-Kamenogorsk is one of the largest cities and industrial centers in Kazakhstan. Non-ferrous metallurgy (Zn–Pb smelter) has acted as a predominating industrial branch in the city since late 1940s. The industrial plants are situated directly adjacent to the residential area of the city which creates grievous ecotoxicological hazard. In the present paper, we aimed at assessing the trace metal pollution of top soils in Ust-Kamenogorsk and its potential threats to the local population. The top soils were sampled at 10 sites throughout the city center. We determined the physical and chemical properties of soils as well as the contents of Cd, Cu, Pb, and Zn. In addition, the soil samples were subjected to a five-step sequential extraction to ascertain the fractionation of trace metals. On this basis, we calculated the geoaccumulation index (I_geo) and pollution load index (PLI) and assessed bioavailability of the elements. From our data, it emerged that the soils displayed a strong polymetallic pollution. PLI was as high as 33.4. Throughout the city, the trace metal contents exceeded the geochemical background and allowable values for residential, recreational, and institutional areas. The I_geo obtained were 3.7–6.5 for Cd, 1.5–4.7 for Cu, 2.8–5.7 for Pb, and 2.6–4.6 for Zn. The soils in Ust-Kamenogorsk displayed extremely high contamination with Cd, moderate to strong contamination with Pb and Zn, and low to moderate contamination with Cu. Cd and Pb were found to be the most bioavailable elements. The mobility of trace metals in the soils changed in the order Cd > Pb > Zn > Cu.     

Competitive sorption of Cd, Cu, Mn, Ni, Pb and Zn in polluted and unpolluted calcareous soils

The objectives of this study were to investigate competitive sorption behaviour of heavy metals (Cd, Cu, Mn, Ni, Pb and Zn) under different management practices and identify soil characteristics that can be correlated with the retention and mobility of heavy metals using 65 calcareous soil samples. The lowest sorption was found for Mn and Ni in competition with the other metals, indicating the high mobility of these two cations. The Freundlich equation adequately described heavy metals adsorption. On the basis of Freundlich distribution coefficient, the selectivity sequence of the metal adsorption was Cu?>?Pb?>?Cd?>?Zn?>?Ni?>?Mn. The mean value of the joint distribution coefficient (K _dΣsp) was 182.1, 364.1, 414.7, 250.1, 277.7, 459.9 and 344.8 l kg^?1 for garden, garlic, pasture, potato, vegetables, wheat and polluted soils, respectively. The lowest observed K _dΣsp in garden soil samples was due to the lower cation exchange capacity and lower carbonate content. The results of the geochemical modelling under low and high metal addition indicated that Cd, Ni, Mn and Zn were mainly retained via adsorption, while Pb and Cu were retained via adsorption and precipitation. Stepwise forward regression analysis showed that clay, organic matter and CaCO₃ were the most important soil properties influencing competitive adsorption of Cd, Mn, Ni and Zn. The results in this study point to a relatively easy way to estimate distribution coefficient values.     

Accumulation of heavy metals in dietary vegetables and cultivated soil horizon in organic farming system in relation to atmospheric deposition in a seasonally dry tropical region of India

Increasing consciousness about future sustainable agriculture and hazard free food production has lead organic farming to be a globally emerging alternative farm practice. We investigated the accumulation of air-borne heavy metals in edible parts of vegetables and in cultivated soil horizon in organic farming system in a low rain fall tropical region of India. The factorial design of whole experiment consisted of six vegetable crops (tomato, egg plant, spinach, amaranthus, carrot and radish) x two treatments (organic farming in open field and organic farming in glasshouse (OFG)) x seven independent harvest of each crop. The results indicated that except for Pb, atmospheric deposition of heavy metals increased consistently on time scale. Concentrations of heavy metals in cultivated soil horizon and in edible parts of open field grown vegetables increased over time and were significantly higher than those recorded in OFG plots. Increased contents of heavy metals in open field altered soil porosity, bulk density, water holding capacity, microbial biomass carbon, substrate-induced respiration, alkaline phosphatase and fluorescein diacetate hydrolytic activities. Vegetable concentrations of heavy metal appeared in the order Zn > Pb > Cu > Ni > Cd and were maximum in leaves (spinach and amaranths) followed by fruits (tomato and egg plant) and minimum in roots (carrot and radish). Multiple regression analysis indicated that the major contribution of most heavy metals to vegetable leaves was from atmosphere. For roots however, soil appeared to be equally important. The study suggests that if the present trend of atmospheric deposition is continued, it will lead to a destabilizing effect on this sustainable agricultural practice and will increase the dietary intake of toxic metals.     

徽县铅锌冶炼区土壤中重金属的空间分布特征

采集甘肃省徽县铅锌冶炼区域土壤样品,分析该区域内重金属污染分布规律及污染特征。结果表明,表层土壤中Pb、Cd、Cu、Zn的平均含量分别为214、3.12、25.8、79.5 mg/kg。研究区域内重金属的分布特征显示,污染浓度由冶炼厂中心向四周递减。纵向0~30 cm范围内重金属含量逐渐降低,大部分重金属污染物集中在土壤表层的0~20 cm区域,其中0~2 cm区域内含量较高,Pb和Cd的最高含量分别达到3 877、24.8 mg/kg,与国家土壤环境质量二级标准(p H 6.5~7.5)(GB 15618—1995)相比,分别超标13、82倍,属于重度污染。重金属元素的分布与土壤有机碳含量及p H相关。冶炼厂周围的重金属污染应引起有关部门的高度重视,严格控制污染源,尽快采取措施以防止污染范围进一步扩大。     

濮阳工业园区土壤重金属背景值及质量评价

为了研究濮阳工业园区土壤重金属背景值,采集了该园区及周边土壤46个样品,测定了土壤中重金属Cu、Zn、Pb、Cr、Cd和Ni的含量,并采用污染负荷指数法和潜在生态危害指数法对土壤质量进行了评价。结果表明:工业园区土壤中Cu、Zn、Pb、Cr、Cd、Ni的背景值分别为36.2、118、49.2、40.6、0.125、15.3 mg/kg;Cu、Zn、Pb、Cd的含量高于河南省土壤重金属背景值;Pb为极强污染,Cu、Zn、Cd为中等污染,重金属污染程度从重到轻的排序为PbZnCuCd,表明濮阳工业园区土壤重金属具有轻微的潜在生态危害。     

Heavy metal uptake by Scirpus Littoralis Schrad. from fly ash dosed and metal spiked soils

Scirpus littoralis is a wetland plant commonly found in Yamuna flood plains of Delhi, India. The ability of Scirpus littoralis to take up and translocate five metals- Mn, Ni, Cu, Zn and Pb from fly ash dosed and metal spiked soils were studied under waterlogged and field conditions for 90 days. Scirpus littoralis accumulated Mn, Ni, Cu, Zn and Pb upto a maximum of 494.92, 56.37, 144.98, 207.95 and 93.08 ppm dry wt., respectively in below ground organs (BO) in 90 days time. The metal content ratios BO/soil (B/S) were higher than shoot/soil ratios (T/S) for all the metals, the highest being for Ni. Metal ratios BO/water (B/W) were also higher than shoot/water (T/W) ratios but the B/W ratio was maximum for Zn. The changes in nutrient status (N, P) in soil water and plants were also studied at interval of 30 days. The Pearson's correlation between metal uptake and N, P uptake were calculated. All the metals except Ni showed negative correlation with nitrogen but they were all non-significant. However, P uptake showed positive correlations with all the metals and all were significant at 1% confidence limit.     

Heavy Metal Availability in Soil Amended with Composted Urban Solid Wastes

A study was performed to evaluate the pH and the availability of Zn, Cu, Mn, Pb, and Ni in soil amended with increasing doses of composted solid wastes, collected in Rio de Janeiro, Rio de Janeiro State and in Coimbra, Minas Gerais State, Brazil. The influence of the time elapsed between compost application to the soil and the sampling of the plant growth substrate (soil + compost) for pH and metal availability analyses was also examined. The availability of heavy metals in the soil, in the compost and in the substrate was evaluated using DTPA solution for metal extraction. The increase of the compost doses added to the soil resulted in the increase of the pH in the substrate. The addition of the compost from the bigger city, Rio de Janeiro, resulted in higher increase in soil pH and available Zn, Cu, Pb, and Ni levels as compared to the addition of the compost from the smaller city, Coimbra. Increasing the time elapsed between the compost application to the soil and the sampling of the mixture resulted in higher available Zn, Cu, Mn, and Pb levels. The addition of the compost from Rio de Janeiro resulted in substrate metal concentrations in the order Zn > Pb > Ni > Cu > Mn and for the Coimbra compost the metal concentrations in the substrate was Zn > Pb > Cu > Ni > Mn. The higher values of pH and available metals obtained for the bigger city were attributed to the greatest metal contamination of its compost.     

Evaluation of Pb, Cu, Zn, Cd, Ni and Fe levels in Rosmarinus officinalis labaiatae (Rosemary) medicinal plant and soils in selected zones in Jordan

The concentration of heavy metals including Pb, Cu, Zn, Cd, Ni and Fe in different parts of Rosmarinus officinalis medicinal plant grown in Jordan were evaluated. Medicinal plant samples and soil samples were collected from three different zones in Jordan (Irbid, Al-Mafraq and Ma’an). Samples were analyzed by atomic absorption spectrometry (AAS) after chemical treatments using acid digestion procedures. Heavy metal levels in washed and unwashed in each part of R. officinalis were analyzed and compared statistically. Results show that concentrations of investigated heavy metals were varied from plant part to another part of R. officinalis. For example, Pb, Zn, Cu and Cd in most parts of R. officinalis in the three zones were concentrated in the following order: flowers, leaves, stems, whereas Pb, Ni and Fe were concentrated in order as follows: leaves, flowers and stems. Heavy metal concentrations in soil samples was evaluated and correlated with their levels in R. officinalis. Two standard reference materials of plant (SRM 1790a; spinach leaves and CRM 281; rye grass) and one standard reference materials of soil (GBW 07406) were examined to validate the method used. Results show that high recoveries were obtained.     

Bioaccumulation of heavy metals in the wolf spider, <Emphasis Type="BoldItalic">Pardosa astrigera</Emphasis> L. Koch (Araneae: Lycosidae)

Previous studies have proposed that Pardosa astrigera L. Koch (Lycosidae) can be used as a biological indicator of heavy metal contamination in soil. In this study, we estimated the bioaccumulation levels and the bioconcentration factors (BCF) of four heavy metals (Cd, Cu, Pb, and Zn) in adult female P. astrigera collected from various field sites according to heavy metal content gradient and broods. The relationship between heavy metal content in the soil and that in spiders was different depending on the heavy metals and the broods. However, heavy metal content in P. astrigera increased with increasing heavy metal content in the soil. While the heavy metal content in the soil was in the order of Zn > Pb > Cu > Cd, its content in P. astrigera was in the order Zn > Cu > Cd > Pb. The BCF for Cd in both of the broods was distinctly higher than those of the other heavy metals evaluated. These results indicate that P. astrigera may be useful as a biological indicator of Cd soil contamination.     

Comparison of leaching tests for the study of trace metals remobilisation in soils and sediments

Several leaching tests were applied and compared to study metal remobilisation on various unpolluted and contaminated soils and on several contaminated sediments. The trace elements considered were Cd, Cr, Cu, Ni, Pb and Zn, and leaching tests consisted of the application of reagents with contrasting characteristics and strengths in order to assess the information provided. An extraction with aqua regia permitted the estimation of the pseudo-total metal content in the sample. Mild extractants such as H2O, CaCl2 and NaNO3 showed low and similar leaching capacities. Acid (CH3COOH) and complexing (EDTA) agents were more effective in remobilising trace metals from soils and sediments. Cd and Zn showed similar extraction characteristics under both extractant solutions, whereas Cu and Pb were more sensitive to complexation, and Ni and Cr to acidification processes. Sequential chemical extractions provided additional information on the association of the trace elements with the different soil and sediment phases. Cd and Zn showed the highest mobility, Pb was associated to reducible solid phases, Cu and Ni to oxidisable phases, and Cr remained mostly in the residual fraction. The results obtained in this paper provided valuable information for choosing a leaching test, which is an instrument of environmental analysis for the estimation of trace metal mobility.