西南涌流域底泥重金属污染特征及潜在生态危害评价

西南涌流域近年来受到比较严重的污染,为了解受重金属污染状况,对该流域底泥重金属污染水平与特征进行了调查与分析,并在此基础上采用地累积指数法和潜在生态危害指数法对西南涌流域底泥重金属污染程度与生态危害进行了评价。结果表明,西南涌流域底泥已不同程度受到重金属Cu、Zn、Pb、Cd、Cr的污染,与珠三角土壤背景值相比,西南涌流域底泥重金属Cu、Zn、Pb、Cd、Cr分别超标11.38、3.32、1.81、19.45、3.20倍;底泥中的Cu、Zn、Cr、Cd之间呈极显著正相关(r=0.615~0.964)。通过地累积指数法评价表明,西南涌流域底泥中的Cd为偏重污染,Cu、Zn为偏中度污染,Pb为轻度污染,Cr为无污染;潜在生态危害指数法评价结果表明,西南涌流域底泥重金属的潜在生态危害程度总体属中等,主要是由Cd的含量过高引起。     

Heavy metal inputs evolution to an urban hypertrophic coastal lagoon, Rodrigo De Freitas Lagoon, Rio De Janeiro, Brazil

This work discusses the temporal variation of metal concentrations in a hypertrophic coastal lagoon located in the metropolitan area of Rio de Janeiro (Brazil). The lagoon watershed includes one of the mostly densely urbanized areas of the city but without industrial activities. Six sediment cores were collected in the lagoon between May and July 2003 and analyzed for the concentration of metals (Fe, Al, Mn, Zn, Pb, Cu, Cr, and Ni). Typical sedimentation rate was calculated as being 0.75 cm year^???1 and was uniform for at least the past 70 years. Therefore, the alterations in the dynamics of the lagoon caused by changes in its watershed were clearly indicated in sediment cores. The construction of an artificial canal to the sea and the increasing urbanization and soil use changes were the major factors affecting metal accumulation in the lagoon sediments. Metals typical of anthropogenic urban sources (Pb, Zn, and Cu) showed increasing loads following urbanization.     

Spatial variation of acid-volatile sulfide and simultaneously extracted metals in Egyptian Mediterranean Sea lagoon sediments

In risk assessment of aquatic sediments, the immobilizing effect of acid-volatile sulfide (AVS) on trace metals is a principal control on availability and associated toxicity of metals to aquatic biota, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides. Spatial variation pattern of AVS, simultaneously extracted metals (SEM), and sediment characteristics were studied for the first time in surface sediment samples (0–20 cm) from 43 locations in Egyptian northern delta lagoons (Manzalah, Burullus, and Maryut) as predictors of the bioavailability of some divalent metals (Cu, Zn, Cd, Pb, and Ni) in sediments as well as indicators of metal toxicity in anaerobic sediments. The results indicated that the ∑SEM (Cu?+?Zn?+?Cd?+?Pb?+?Ni) values in sediments of lagoon Burullus had higher concentrations than those of Maryut and Manzalah. In contrast, AVS concentrations were considerably higher in lagoons Manzalah and Maryut and seemed to be consistent with the increase in organic matter than lagoon Burullus. Generally, the average concentrations of the SEM in all lagoons were in the order of Zn?>?Cu?>?Ni?>?Pb?>?Cd. The ratios of ∑SEM/AVS were less than 1 at all the sampling stations except at one station in lagoon Maryut as well as four stations located in lagoon Burullus (∑SEM/AVS?>?1), which suggests that the metals have toxicity potential in these sediments. Therefore, SEM concentrations probably are better indicators of the metal bioavailability in sediments than the conventional total metal concentrations.     

Heavy metal and polycyclic aromatic hydrocarbons in Ebrié lagoon sediments, Côte d’Ivoire

Surface sediments throughout Ebrié lagoon, Côte d’Ivoire were collected in 2001 and analyzed for their heavy metal and polycyclic aromatic hydrocarbons (PAH) contaminant content. Geochemical maps of heavy metals (Cd, Cu, Zn, Fe, and Mn) in the surface sediment were produced based on geographical information system (GIS) technology. Heavy metals and PAH were detected at high concentration and provide evidence for several anthropogenic inputs to the lagoon. A significant spatial relationship was found for Fe, Zn, and Cu in the sediment using a GIS-based analysis, suggesting that these metal contaminants in the sediments of the Biétri bay had common sources.     

Water quality and heavy metal monitoring in water and sediment samples of the Küçükçekmece Lagoon, Turkey (2002–2003)

Physical and chemical parameters have been analyzed in water samples from a brackish water lagoon, Küçükçekmece, located on the western outskirts of Istanbul. Samples were collected every two months for a year from nine sampling stations. Of the parameters measured, temperature, pH, salinity, nitrate and phosphate showed changes when compared with the previously published data. The lagoon was found eutrophic as it was reported previously. Sulphate and COD levels were higher when compared with the standards established by the Turkish Water Pollution and Control Regulation. Additionally, concentrations of heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn) in water and bottom sediments were measured and compared with the standards established by the Turkish Water Pollution and Control Regulation and with the previously published data. The results were analysed statistically with respect to location and any relationships between the concentration of the elements in corresponding water and sediment samples were examined. Principal Component Analysis of water samples allowed us to discriminate three areas affected mainly by heavy metal contamination, possibly due to industrial, commercial and/or urban activities. Generally, the concentrations of the heavy metals were higher at stations near the three estuaries, suggesting a direct influence of the three creeks on the pollution of the Küçükçekmece Lagoon. Although elevated levels of Cd were recorded in several water samples, it was not detected in sediment. On the other hand, a particularly high level of Cr pollution was recorded most of the water and sediment samples.     

Heavy Metal Levels in Biota and Sediments in the Northern Coast of the Marmara Sea

Concentration of Cd, Co, Cr, Ni, Zn, Fe, Mn, Pb and Cu were determinedin biota and sediment samples collected from the Marmara Sea in Turkey. The levels of Zn, Fe, Mn, Pb and Cu in the macroalgae are higher than previous studies in the Marmara Sea. Moreover, Cu and Zn concentrations at the present study are significantly high than Bosphorus and Black Sea algae. The order heavy metal concentrations in the mussel samples was: Fe > Zn > Ni > Mn > Cu > Pb > Cr > Cd > Co. The metal concentrations are generally lower when compared with the Black Sea mussels except Pb. At the same time, concentrations of Pb, Cu and Zn in the mussel species are lower when compared with the results in the Aegean Sea. The ranges of Mn and Cu in the tested fish samples are higher than Black Sea fish. On the other hand, Cd, Co, Cr, Zn and Pb concentrations are lower. The northern coast of the Marmara Sea having the highest metal concentrations in sediments as follows: Co, Cr, Ni, Fe at ?arköy ; Pb, Cu at M. Ere?li; Cd, Zn, Mn at Menek?e. The heavy metal levels in the sediment samples are lower than other areas in the Marmara Sea.     

The Influence of the Biometric Parameters on Metallothionein and Metal Level in the Heat-Treated Cytosol of the Whole Soft Tissue of Transplanted Mussels

The influence of the biometric parameters (shell mass, whole soft tissue mass, condition index) on MT and metal levels in the heat-treated cytosol of the whole soft tissue of transplanted mussels was studied over the period of one year. The positive correlation of three metals (Cd, Fe, Zn) with the shell mass indicated to time-dependent increase of their contents. Strong correlation of Mn content with the whole soft tissue mass (r = 0.74, p < 0.0001), and almost identical changes of these two parameters over the year make Mn a good indicator of mussel's condition. As opposed to the other metals, Cu content does not exhibit connection with biometry. On the other hand, MTs are highly influenced by biometry. As much as 65% of their variability could be explained by the changes of the shell mass and the whole soft tissue mass. Consequently, it is difficult to distinguish if the obtained positive correlation between Cd and MTs (r = 0.48, p < 0.05) reflects MT induction by Cd, or Cd accumulation as a result of age-dependent increase of MTs. Due to the strong influence of the biometry on MT level, the whole soft tissue is not considered as the best choice for measuring MTs as a biomarker. Better option would be to isolate a specific tissue that shows indisputable connection between MT induction and metal accumulation.     

Assessment of heavy metal enrichment in the offshore fine-grained sediments of the Caspian Sea

Sampling of the offshore seabed sediments of southwestern part of the Caspian Sea was carried out by gravity corer in order to study heavy metal concentration and the physicochemical factors controlling their distribution in the fine-grained fraction. The grain size distribution, amount, and type of clay minerals, total organic carbon (TOC) content, and Eh–pH of the sediments were determined. The average concentrations of the heavy metals in ppm are Mn (563), Cu (207.5), Sr (187), Zn (94), Pb (26.3), Ni (14.5), Co (11.5), Cd (2.56), and Ag (1.04) in their order of abundances. Co and Zn mostly indicate increase in silt-size fraction of the sediments suggesting their probable detrital provenance but the Mn, Ni, Cu, Sr, Pb, Cd, and Ag concentrations show a similar trend to distribution of the clay-size fraction. The concentrations of Mn, Co, and Cd increase with increase in the TOC content but the Cu, Pb, Ni, Ag, and Sr concentrations decrease with increase of the TOC content. The amounts of Zn, Cu, Sr, Pb, Cd, and Ag increase with increase in the CaCO₃ content. The calculated enrichment factor indicates that the sediments are very strong to extremely enriched in Ag, significantly enriched in Cu and Cd, and depleted to mineral for Pb, Sr, Co, Ni, and Zn. Variations of the Cu, Sr, Cd, Ag, and Pb concentrations are similar to the clay and CaCO₃ distributions.     

Spatial distribution and transport of heavy metals in soil, ponded-surface water and grass in a pb-contaminated watershed as related to land-use practices

The aim of this study was to investigate the spatial distribution of heavy metal in soil and evaluate the dissolution of metal from soil to ponded-surface water, leaching through soil profiles and metal uptake in grass as related to different land-use practices. The data provided a scientific basis for best-management practices for land use in Khli Ti watershed. The watershed has a Pb-contamination problem from the previous operation of a Pb-ore concentrator and abandoned Zn–Pb mine. Sampling sites were selected from a land-use map, with land-use types falling into the following four categories: forest, agricultural land, residential area and road. Soil, ponded-surface water, grass samples and soil profiles were collected. The study related soil characteristics from different land-use practices and locations with observed metal concentrations in ponded-surface water and soil. High enrichment factors of Pb and As in soil were found. Partitioning coefficient, K_d values were in the order: Cr > Pb > Ni > Cu > Cd > Zn. Soil disturbance from land-use activities including tillage and traffic increased leaching of trace metal from soils. Pb in soil was significantly taken up by grass even though the Transfer Factor, TF values were rather low. Agricultural activities in the watershed must be limited. Moreover, land encroachments in the upper and middle part of the watershed which have high potential of Pb must be strictly controlled in order to reduce the Pb contamination from non-point sources.     

The impact of the tunnel exhausts in terms of heavy metals to the surrounding ecosystem

Samples of soil, plants, and lichens were analysed for heavy metal content (Cd, Cr, Cu, Ni, Pb, and Zn) in relation to different distances from the tunnel ventilation systems in order to evaluate the environmental pollution caused by car exhausts pollution from the Tauerntunnel and the Katschbergtunnel (Austria). Results show that the extent of heavy metal pollution is related to the type of tunnel ventilation system. The vertical ventilation system which ends in an exhaust air tower in the alpine pasture of Mosermandl 1,900 m above sea level contaminates soils and plants up to a distance of 750 m from the exhaust source. The dispersion of metals in front of the horizontal ventilation systems, which are located next to the tunnel portals, exhibits a rapid decrease with distance. Lichen transplants placed in front of the horizontal ventilation systems show very high metal accumulation, which gradually declines with the distance from the emitter source, therefore the lichen species Pseudevernia furfuracea can be used as a very efficient biomonitor for monitoring heavy metal pollution caused by tunnel exhausts over time. Data from former years (1986, 1988, 1990 and 1992) and from this present research suggest that the contamination of heavy metals at Mosermandl has decreased slightly in soil samples, except for Cu, but increased in plant samples, whereas a significant increase of Pb was observed.