HEAVY METAL DISTRIBUTION AND SPECIATION IN THE NORTHERN ADRIATIC SEA

In the present study the concentrations of cobalt, copper, iron, manganese, zinc were analysed and the speciation of copper and zinc performed, with a summer and winter sampling, for two areas in the Northern Adriatic Sea and crossing at the farthest zones of the Po river-sea water interface. Results show that when salinity increases the concentrations of all investigated metals (with the exception of cobalt) present some degree of biogeochemical cycling. Copper is the element whose dissolved phase has the highest importance in metal transport across the salinity gradient. Results of speciation analysis demonstrate that the presence of excess amounts (5-8 fold) of unbound ligands confers a buffering capacity for potential inputs of dissolved metals into the Northern Adriatic Sea. The speciation of both copper and zinc in the dissolved phase was dominated by organic complexation.     

Metal distribution in sediments from the Adriatic Sea

Total metal concentrations (Cu, Ni, Pb, Zn, Fe, and Mn) and their distribution in different chemical forms (speciation) were determined in sediments from the Adriatic Sea in order to evaluate contamination and mobility of metals. The study was carried out on marine sediments collected in two areas of the Adriatic Sea differently influenced by Po river waters. Metal distribution in the study area depends prevalently on water circulation and on organic matter distribution. Among metal levels, significant correlations between copper and zinc and between lead and nickel were found, suggesting common and specific sources. As regards metal speciation, the distribution of different chemical forms changes with the metal. The prevailing zinc phases, for example mobile forms, and sulphide together are greater than 50% of total metal. Nickel is mainly present in sediments as sulphide, and the preferential association of copper with organic matter is evident. Lead and manganese are preferentially found as mobile forms (more of 30% for lead, 40% or more for manganese).     

The Influence of Anthropogenic Contamination On Metals Release From Coastal Sediment Suspensions with Aerated Sea Water

The zinc, cadmium, copper and lead release from the uncontaminated and contaminated coastal sediments with aerated sea water was studied. the metals transfer to the dissolved forms was monitored during one-two months by differential pulse anodic voltammetry (DPASV). the sediments with different initial degree of contamination were sampled in the Peter the Great Bay, Sea of Japan around Vladivostok-the biggest city in Russian Far East. Sediment contamination by metals led to increased release to solution of zinc due to sulphide oxidation and cadmium on account of organic matter decomposition. the copper behaviour was complicated by strong binding with organic matter and enhancements of copper release can only be seen in sediment with a low organic matter content. Significant lead transfer to dissolved forms was not observed regardless of sediment contamination. the temperature affected the release of cadmium and copper through enhanced organic matter destruction. the dissolved metal fluxes from the sediment transformation are compared with metal fluxes towards bottom. Such comparisons show that second contamination by dissolved metals of the studied coastal environment may be important for cadmium only.     

The Influence of Anthropogenic Contamination On Metals Release From Coastal Sediment Suspensions with Aerated Sea Water

The zinc, cadmium, copper and lead release from the uncontaminated and contaminated coastal sediments with aerated sea water was studied. the metals transfer to the dissolved forms was monitored during one-two months by differential pulse anodic voltammetry (DPASV). the sediments with different initial degree of contamination were sampled in the Peter the Great Bay, Sea of Japan around Vladivostok-the biggest city in Russian Far East. Sediment contamination by metals led to increased release to solution of zinc due to sulphide oxidation and cadmium on account of organic matter decomposition. the copper behaviour was complicated by strong binding with organic matter and enhancements of copper release can only be seen in sediment with a low organic matter content. Significant lead transfer to dissolved forms was not observed regardless of sediment contamination. the temperature affected the release of cadmium and copper through enhanced organic matter destruction. the dissolved metal fluxes from the sediment transformation are compared with metal fluxes towards bottom. Such comparisons show that second contamination by dissolved metals of the studied coastal environment may be important for cadmium only.     

The common mussel Mytilus edulis as an indicator of trace metals in Scandinavian waters. I. Zinc and cadmium

Concentrations of zinc and cadmium in whole soft parts of mussels, Mytilus edulis (L.), collected from 54 locations in Scandinavian waters were determined. Local variations in concentrations of the two metals found in samples taken close to industrial sources of zinc and cadmium confirmed the ability of the mussel to act as an accurate indicator of pollution by these metals over the entire range of salinities in which this species can exist. In addition, offshore samples remote from industrial discharges revealed higher concentrations of zinc and cadmium in mussels from lowsalinity areas (Gulf of Finland, Southern Bothnian Sea, Baltic proper) than in those from high-salinity areas (Kattegat, Eastern Skagerrak). Major decreases in metal concentrations present in the mussel were apparent in the regions of the Sound and the Great Belt, which are areas of rapid salinity change due to mixing of Baltic water with water from Kattegat. Comparison of these results with those reported for zinc and cadmium in water throughout the study area suggested the existence of a higher biological availability of these metals in regions of low salinity; possible reasons for this are discussed. Data from the present survey are also compared to those reported for mussels taken elsewhere. This comparison reveals the Baltic area to be considerably polluted by trace metals; in contrast, the waters of Kattegat and skagerrak are considered to be relatively unpolluted.     

The Influence of Temperature and Salinity Upon the Acute Toxicity of Heavy Metals to the Banana Prawn (Penaeus merguiensis de Man)

Bioassays were conducted to determine the effects of temperature and salinity on the acute toxicity of mercury, copper, cadmium, zinc, nickel and lead to juvenile banana prawns (Penaeus merguiensis de Man). Tests were conducted at all combinations of 35, 30 and 20°C with 36 and 20° salinity over 96 h. The general rank order of metal toxicity was Hg > (Cu, Cd, Zn) > Ni > Pb. The toxicity of all metals increased with increased temperature. This was most noticeable in the high salinity treatments, particularly for copper and zinc. Salinity appeared to influence the toxicity of all metals tested although significant differences were only found for copper and lead at 20°C. At this temperature prawns were markedly more susceptible to both metals in low salinity sea water. The data are compared with lethal concentrations found for other crustaceans and are discussed in relation to existing water quality criteria.     

Spatial and seasonal variability of dissolved oxygen and nutrients in the Southern Adriatic coastal waters

The main objective of this paper is to present vertical and horizontal patterns of dissolved oxygen and nutrients found during four seasonal surveys (March, June, September and December 2000) in the Southern Adriatic Sea coastal waters. The multivariate technique Principal Component Analysis has been applied to our dataset considering the following parameters: seawater temperature, salinity, dissolved oxygen and nutrients (nitrate, nitrite, phosphate, silicate). The resulting plot shows in a self-explanatory way that a seasonal trend was not observable in the investigated period and that no significant differences occur between the stations sampled in the Taranto Gulf and those along the Adriatic coast. Water column stratification persists in all seasons, except in spring, in the shallowest stations. The surface layer is characterized by a low nutrient content. The influence of the Northern Adriatic Surface Water in the Southern Adriatic sub-basin seems to be very low and can be traced by nitrate and silicate only in spring and winter. Regarding deep waters, nitrate distribution shows an increasing gradient moving from the coast to the open sea, having the lowest concentration in the shelf area and the highest in the most offshore stations of the Otranto Strait. In the Otranto Strait area the vertical distributions of physical and chemical parameters show, at middle depths, the inflow of Levantine Intermediate Water, traced by both the maximum of salinity, nitrate and phosphate and the minimum of oxygen. The LIW signal is lost moving northward. The outflow of Adriatic Dense Water is less evident, being traced only in spring by an oxygen increase at the bottom layer in the shelf area. The N:P ratio is highly variable but in the range already observed in the Southern Adriatic, suggesting a P-limitation, which can both contribute to the low primary productivity of the area and support the N:P ratio anomaly of the Eastern Mediterranean.     

Spatial and seasonal variability of dissolved oxygen and nutrients in the Southern Adriatic coastal waters

The main objective of this paper is to present vertical and horizontal patterns of dissolved oxygen and nutrients found during four seasonal surveys (March, June, September and December 2000) in the Southern Adriatic Sea coastal waters. The multivariate technique Principal Component Analysis has been applied to our dataset considering the following parameters: seawater temperature, salinity, dissolved oxygen and nutrients (nitrate, nitrite, phosphate, silicate). The resulting plot shows in a self-explanatory way that a seasonal trend was not observable in the investigated period and that no significant differences occur between the stations sampled in the Taranto Gulf and those along the Adriatic coast. Water column stratification persists in all seasons, except in spring, in the shallowest stations. The surface layer is characterized by a low nutrient content. The influence of the Northern Adriatic Surface Water in the Southern Adriatic sub-basin seems to be very low and can be traced by nitrate and silicate only in spring and winter. Regarding deep waters, nitrate distribution shows an increasing gradient moving from the coast to the open sea, having the lowest concentration in the shelf area and the highest in the most offshore stations of the Otranto Strait. In the Otranto Strait area the vertical distributions of physical and chemical parameters show, at middle depths, the inflow of Levantine Intermediate Water, traced by both the maximum of salinity, nitrate and phosphate and the minimum of oxygen. The LIW signal is lost moving northward. The outflow of Adriatic Dense Water is less evident, being traced only in spring by an oxygen increase at the bottom layer in the shelf area. The N:P ratio is highly variable but in the range already observed in the Southern Adriatic, suggesting a P-limitation, which can both contribute to the low primary productivity of the area and support the N:P ratio anomaly of the Eastern Mediterranean.     

Spatial Variations of Heavy Metals in the East China Sea Continental Shelf Surface Sediments

Surface sediments collected from continental shelf of the East China Sea were analyzed for heavy metals (iron, manganese, copper, zinc, lead, cadmium), carbonate, organic carbon contents, and grain sizes. the range of concentrations observed were iron: 0.3-1.3 wt%, manganese: 2.3-14 μmole/g, copper: 7.1-184 μmole/g, zinc: 0.16-0.77μmiole/g, lead: 15-98 μmole/g, cadmium: 0.17-3.9 μmole/g, carbonate: 3.6-87 wt%, sand: 10-100%, silt: 0-70% and clay: 0-50%.

A zonal distribution pattern of the heavy metals was found in the East China Sea Continental shelf sediments. High concentrations of most heavy metals, organic carbon and fine-grained sediments were observed in the inner shelf zone, especially those near the discharge of the Yangtze River. Concentrations of these heavy metals decreased from the inner shelf to the shelf break region. High concentrations of metals were also found in sediments near Taiwan. Iron concentrations decreased north-east of the central shelf region. High concentrations of cadmium were found in the shelf break region where biogenic carbonate is predominant. This study showed that biogenic carbonate in the East China Sea shelf break region and the terrigenous sediments from the Yangtze River and island of Taiwan were the major sources of heavy metals. Heavy metal concentrations were strongly influenced by the content of the coarse-grained quartz sand present in the sediments.     

Spatial Variations of Heavy Metals in the East China Sea Continental Shelf Surface Sediments

Surface sediments collected from continental shelf of the East China Sea were analyzed for heavy metals (iron, manganese, copper, zinc, lead, cadmium), carbonate, organic carbon contents, and grain sizes. the range of concentrations observed were iron: 0.3-1.3 wt%, manganese: 2.3-14 μmole/g, copper: 7.1-184 μmole/g, zinc: 0.16-0.77μmiole/g, lead: 15-98 μmole/g, cadmium: 0.17-3.9 μmole/g, carbonate: 3.6-87 wt%, sand: 10-100%, silt: 0-70% and clay: 0-50%.

A zonal distribution pattern of the heavy metals was found in the East China Sea Continental shelf sediments. High concentrations of most heavy metals, organic carbon and fine-grained sediments were observed in the inner shelf zone, especially those near the discharge of the Yangtze River. Concentrations of these heavy metals decreased from the inner shelf to the shelf break region. High concentrations of metals were also found in sediments near Taiwan. Iron concentrations decreased north-east of the central shelf region. High concentrations of cadmium were found in the shelf break region where biogenic carbonate is predominant. This study showed that biogenic carbonate in the East China Sea shelf break region and the terrigenous sediments from the Yangtze River and island of Taiwan were the major sources of heavy metals. Heavy metal concentrations were strongly influenced by the content of the coarse-grained quartz sand present in the sediments.     

The common mussel Mytilus edulis as an indicator of pollution by zinc,cadmium, lead and copper. I. Effects of environmental variables on uptake of metals

The net uptake of zinc, cadmium, lead and copper by the common mussel Mytilus edulis (L.) exposed to different conditions was investigated with a view to using this species as an indicator of contamination of the marine environment by these metals. The variables studied were season, position of the mussel in the water column, water salinity, water temperature, and the simultaneous presence of all four metals. Each of these 5 variables affected the net uptake of some or all of the metals studied under some conditions. Seasonal variation in concentrations of zinc, cadmium and copper was found in samples collected at three separate locations. The relationship of seasonal variation to tissue weight and absorption route of the metals is discussed. Near to freshwater inputs of trace metals, the concentrations of zinc, cadmium and lead in mussels were found to vary according to the depth at which the mussels were collected; in summer when freshwater run-off is less, this effect was absent. Low salinities did not affect the net uptake of zinc by mussels, but increased the net uptake of cadmium and decreased that of lead. Low temperatures had no effect on the net uptake of zinc or lead; the net uptake of cadmium was unaffected by low temperatures at high salinities but was decreased by low temperatures at low salinities. The presence of the other metals had no effect on the individual net uptake of either zinc, cadmium or lead. A sampling programme was devised to eliminate the effects of these environmental variables and to allow the use of M. edulis as an indicator of zinc, cadmium and lead in marine and estuarine environments. In contrast to the other metals, the net uptake of copper by the mussel was extremely erratic, and was affected by salinity and temperature changes and by the presence of the other metals and changes in their relative concentrations. The effects of other metals on the net uptake of copper cannot be easily eliminated or allowed for; it is, therefore, suggested that the mussel should not be used as an indicator of copper in the marine environment.     

Total and bioavailable metals in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo): relation to genetic variation in plant populations

Knowledge of total and bioavailable metal contents in soil is important for regional risk assessment and management. The main objective of the present study was to analyse the concentrations of metals in soils in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo). Genetic variation of plant populations was investigated to assess the potential impact of metal contamination on forest sustainability. The levels of copper, cobalt, zinc, arsenic, and lead were significantly higher (up to 200-fold) in mining sites in the Lubumbashi compared to the most highly contaminated Sudbury sites. The nickel content in soil samples from Lubumbashi was much lower compared to Sudbury region samples. Only 3.5% and 4 % of total copper and nickel, respectively, were phytoavailable, with values of 6%, 5.7%, 3.6%, and 5.4% for cobalt, magnesium, manganese, and zinc, respectively. There were significant positive correlations between total metal and phytoavailable metal concentrations for copper (r=0.99), nickel (r=0.86), cobalt (r=0.72), strontium (r=0.71), and zinc (r=0.66). Although genetic variation was high in Picea glauca populations from the Sudbury region, no association was found between metal contamination levels and genetic variation within and among the P. glauca populations.     

Relationships between dissolved and particulate carbohydrate temporal patterns and mucilaginous aggregates formation: evidences from time series analysis and biochemical composition of aggregates

A 3-year monitoring of dissolved and particulate carbohydrate concentrations in four transects located in the Adriatic and Tyrrhenian Seas was performed in order to get information on the role played by carbohydrates in the mucilage formation in these areas. The application of time series analysis pointed out that the concentration of dissolved carbohydrates does not vary significantly in coincidence of the mucilage appearance showing an almost constant state with respect to time. In contrast, wider temporal variations of carbohydrate amounts, either increase or decrease, were observed when mucilages were lacking or reduced. This almost constant state of carbohydrate amounts observed in presence of mucilages that we define 'steady state' could be associated to an alteration of the complex chemical equilibrium between synthesis and degradation (either hydrolysis or oxidation) reactions of the organic polymers which are typical of the humification processes in the marine environment. The results of this study suggest that the monitoring of carbohydrates can represent an useful tool for the comprehension of the most relevant phenomena of mucilage appearance in the Northern Adriatic Sea.     

Metal transport phases in rivers around Jameshedpur†

Transport phases of four metals of geochemical and water quality importance were investigated in rivers around Jamshedpur. The metals iron, manganese, zinc and copper were partitioned into dissolved, adsorbed and or ion exchangeable, solid organic, oxide coating and crystalline phases applying filtration for the dissolved phase and a chemical fractionation scheme for the particulates. Iron and copper were transported mainly in the particulate phases at all sites, while manganese and zinc were found in the dissolved phase up to a hundred percent depending on the pH of water sample and pollution at the site concerned. Except copper more than 75 percent of all other three metals occurred in transport modes thought to be available to aqueous and biotic interactions. Copper was in available phases from 50 to 70 percent. The significance of metal partitioning as a factor in controlling metal availability and toxicity to biota is discussed.     

Metal distribution in marine sediments of the Mar Piccolo in Taranto (Ionic Sea,southern Italy)

The spatial distribution of selected metals (Fe, Ni, Mn, Zn, Cu, Pb, Hg and Cd) and their partition in the different chemical forms (speciation) were determined in benthic sediments from Mar Piccolo, Taranto (Ionic Sea, southern Italy). The aim of this study was to assess the degree of sediment contamination and bioavailability of metals, very important for Italian mussel culture, in a semi-enclosed marine ecosystem. In sediments, grain size distribution, total organic carbon (TOC), and humic (HA) and fulvic (FA) acids contents were also determined. The compounds TOC, HA and FA, in fact, have a great influence on metal complexation. High concentrations of copper, lead, zinc and mercury were found, especially in sediments of the first inlet of Mar Piccolo. Statistical analysis of results shows significant correlation among Cu, Pb and Zn concentrations and the influence of organic matter on the sediment distribution of Cu, Pb and Zn. Metal speciation analysis, carried out with sequential extraction method, shows that Fe and Ni are present in sediments mainly as sulphides. Mn and Pb are present principally in an ion-exchangeable form or bound to carbonate and Cu is associated to organic matter. Metal pollution index (MPI), calculated as a weighed mean of the metal contamination factors in each station, shows that with regard to Cu, Ni, Pb and Zn, some stations investigated are unpolluted (MPI <1), whereas in other areas, pollution level is not very high. On the contrary, for mercury, the pollution level in the first inlet of the basin is very high.     

Speciation of heavy metals in Albanian coastal sediments

This article presents results on heavy metal (Fe, Mn, Cr, Ni, Cu, Cd, Pb and Zn) speciation in the coastal sediments of Albania. Sediment samples were collected within the framework of the activities of the Interreg Italia–Albania Project, carried out in the Southern Adriatic Sea in 2000–01. This study shows that Albanian coastal sediments are highly influenced by river input, as the decreasing concentrations from coast to offshore confirm. Pb represents an exception of the general trend; meteoric inputs are prevalent for this metal. Ni, Cr, Fe, Zn and Cu correlate significantly and positively in the entire area, indicating a common origin for these metals in the analyzed sediments. All metals result mostly associated to the most refractory phases, which constitute up to 80% of the total concentration. Nevertheless a recent input of Cr, Ni, Cu and Mn can be observed, as the result of mining and industrial activities, in some selected areas, such as the Drin Bay and Durres. Their high concentration in the bioavailable phase can determine toxic effect upon biota.     

污灌土壤中铜和锌含量及其微域分异

本文通过对污灌土壤中铜和锌总量和形态含量及其分布的研究,揭示了铜和锌总量和诸形态含量的微域分异规律,从而为污灌区农田土壤重金属污染的评价提出了新的依据。     

Metals in Zooplankton from the Baltic Sea, 1980-84

Between 1980 and 1984, plankton was collected for metal analysis during four expeditions in the Baltic Sea. for comparison, samples from adjacent areas of the northeastern Atlantic Ocean were also taken. the mixed net-plankton samples were analyzed by AAS for metals (Al, Cd, Co, Cr, Cu. Fe, Mn, Ni, Pb, and Zn). the results are discussed with regard to spatial and temporal trends and for comparison with data from other authors. Correlations among the contents of the different metals and between the metal contents and 'external factors' including salinity, season, percentage of co-collected phytoplankton, and concentration of dissolved and particulate metals in the water are considered.

There is a tendency for higher metal contents in plankton from the brackish Baltic Sea (Al, Mn and Hg), while other metals (e.g. Cd) show higher levels in samples taken from the marine environment. Except for mercury, no clear correlations could be found between the metal content in plankton and the dissolved concentration of the same metal in the ambient water. Otherwise, the contents of aluminium, iron, manganese and zinc in the suspended particulate matter and in the plankton seem to be partly related to each other.     

An assessment of copper,zinc and cadmium contamination and their ecotoxicological effects in O. mediterranea Costa, 1853 (Amphipoda,Talitridae)

This study was conducted to compare metals bioaccumulation in the Talitrid O. mediterranea collected from the banks of Bizerte lagoon. Individuals were exposed to a series of contaminated soil with different concentrations of cadmium, copper, and zinc. Biological and physiological responses were highlighted. Body metals concentrations were measured in the talitrid using flame atomic emission spectrometry. Results showed that after the second week, the mortality increased especially with cadmium exposure, and a mass gain was obtained between weeks for copper and zinc. Furthermore, the concentration factor indicated that O. mediterranea could be considered as a macroconcentrator of copper and zinc. Histopathological analysis showed that the different metals concentrations induced significant changes in the morphology and in the ultrastructural organisation of hepatopancreatic cells. Significant alterations obtained after metals exposure were the increase in the number of the majority cell organelles. Also, heavy metals were present in the form of numerous granules with different size in the cell surface. Furthermore, metals exposure affected the brush border causing the disruption of microvilli filament. Through these results, O. mediterranea could be a good indicator providing measurable responses. It could be an attractive candidate for the biochemical study of heavy metals toxicity in coastal ecosystems.     

Water quality in a mediterranean marine protected area (North Sporades Islands,Greece)

Pollution in the marine protected area of North Sporades Islands was investigated in July 1997. Salinity, temperature, dissolved oxygen, dissolved inorganic nutrients, organic carbon, hydrocarbons as well as dissolved and particulate trace metals were determined at 15 offshore and coastal stations. Dissolved organic carbon and inorganic nutrient concentrations indicate the mesotrophic character of the investigated waters. The dissolved forms of nitrogen were slightly higher at coastal stations. Dissolved and particulate Cu, Zn and Ni, were higher in coastal stations, whereas concentrations of Pb were generally low and likely of atmospheric origin. Dissolved/Dispersed petroleum hydrocarbons (DDPH) were close to detection limits at all stations. Temperature and salinity vertical profiles, nutrient and trace metal concentrations revealed the presence of a slight influence of the Black Sea water coming from Dardanelles straits.