Chemistry,mineralogy and radioactivity in posidonia oceanica meadows from North-Western Sicily

This paper presents measurements of major, minor, metal trace elements and radionuclides in sediments and in Posidonia oceanica samples from north-western Sicily (Italy). The mineralogical and chemical composition of sediments were determined by X-ray diffraction and X-ray fluorescence techniques, respectively. A flame atomic absorption spectrophotometry was used to measure concentrations of Cu, Zn, Cd and Pb in P. oceanica samples and in sediments. Specific activities of selected radionuclides have been determined by high-resolution gamma spectrometry. Standard statistical analysis was used to assess correlations between different elements and different sample types.     

Influence of hydrodynamic conditions on the production and fate of Posidonia oceanica in a semi-enclosed shallow basin (Stagnone di Marsala,Western Sicily)

An integrated approach using hydrodynamic and transport numerical models, lepidochronology and stable isotope analysis was used to investigate how local hydrodynamic conditions influence the primary production and fate of the seagrass Posidonia oceanica in a Mediterranean semi-enclosed marine system (Stagnone di Marsala). The water mass exchange aptitude of different sectors of the basin was analysed, and data collected were used to select two sectors (colonized by Posidonia oceanica showing the lowest and highest water exchange values) for biological analyses. According to the mean dispersal coefficient differences simulated by the hydrodynamic model, growth rate and primary production of P. oceanica differed between sectors, with average values lower in the central sector where water exchange is lower than in the southern sector. Although P. oceanica coverage and primary production were higher in the southern sector, carbon and nitrogen stable isotope analysis suggests that the transfer of seagrass organic matter to higher trophic levels of the food web was higher in the central sector. The possibility of a link between hydrodynamism, production and fate of organic matter is proposed to explain the observed patterns.     

Influence of hydrodynamic conditions on the production and fate of Posidonia oceanica in a semi-enclosed shallow basin (Stagnone di Marsala, Western Sicily)

An integrated approach using hydrodynamic and transport numerical models, lepidochronology and stable isotope analysis was used to investigate how local hydrodynamic conditions influence the primary production and fate of the seagrass Posidonia oceanica in a Mediterranean semi-enclosed marine system (Stagnone di Marsala). The water mass exchange aptitude of different sectors of the basin was analysed, and data collected were used to select two sectors (colonized by Posidonia oceanica showing the lowest and highest water exchange values) for biological analyses. According to the mean dispersal coefficient differences simulated by the hydrodynamic model, growth rate and primary production of P. oceanica differed between sectors, with average values lower in the central sector where water exchange is lower than in the southern sector. Although P. oceanica coverage and primary production were higher in the southern sector, carbon and nitrogen stable isotope analysis suggests that the transfer of seagrass organic matter to higher trophic levels of the food web was higher in the central sector. The possibility of a link between hydrodynamism, production and fate of organic matter is proposed to explain the observed patterns.     

Effect of dye auxiliaries on chemical oxygen demand and colour competitive removal from textile effluents using Posidonia oceanica

The use of an abundant and widely distributed seagrass species, Posidonia oceanica, as a biosorbent for the direct dye Yellow 44 was successfully shown. The studies were performed on the single dyestuff dissolved in water and in a dyebath containing agents commonly used in the textile industry, i.e. a surfactant (Lavotan TBU), a sequestring agent (Meropan DPE), a softening agent (Eurosoft CI10) and a salt (NaCl). The colour reduction results showed that P. oceanica was found to be more efficient for removal of Yellow 44 from an aqueous solution (162 mg g^?1) than from a dyebath solution (135 mg g^?1), according to the Langmuir isotherm model. For the single dyestuff sorption, Fourier transform infrared and X-ray photoelectron spectroscopy studies highlighted chemical sorption between the dye alcohol function and the sorbent acid function. The chemical oxygen demand removal percentages were found to be 54.9 and 76.6% for Yellow 44 dissolved in aqueous solution and in dyebath solution, respectively. This confirmed the both sorption of the chemical auxiliaries and the dye on P. oceanica.     

Heavy metal accumulation in algae and sediments of the Black Sea coast of Turkey

The paper reports heavy metal accumulation in algae collected at four stations and in sediments at three stations on the Black Sea coast of Turkey. The metals analysed are Cd, Co, Cr, Cu, Fe, Pb, Sb and Zn. The metal content of algae increased generally (with some exceptions) from 1991 till 1993 in ?ile and Sinop. In the sediments Sb in ?ile, As in Riva, Fe, Zn in Sinop are high. According to these findings the metal pollution increased in Turkish area of the Black Sea during the years investigated.     

Heavy Metal Pollution in Sediment from the Eastern Adriatic Coast,Croatia

Abstract

Sediment samples were collected from the Adriatic Sea in areas near large coastal towns along the eastern Adriatic coast (Zadar, [Ncirc]ibenik, Split, Plo?e and Dubrovnik).

Considerable quantities of untreated effluents are discharged via freshwater runoff and a variety of industrial waste waters, significantly affecting the quality of marine sediments.

Distribution of some trace metals (Pb, Cu, Ni, Cr, Zn, Mn, Cd, and Al) involved in problems related to metal pollution in Adriatic sediment were examined. Values are expressed as a total concentration of heavy metals of sediment dry weight.

Spatial distribution of some trace metal values in sediments and correlation of results for grain size effect were examined. the trace elements in marine sediments generally remain in the fine grained fraction, often in the silt-clay fraction. Higher values of heavy metals in some areas (Split, Sibenik) could be attributed to anthropogenic effects, i.e. to land-based activities. the main cause of higher values of some metals at open sea sites and in some coastal areas are probably caused naturally by sedimentation processes in those areas. Our results show that the sediments undoubtedly play a key role in determining the transport and ultimate fate of contaminants.     

Spatial distribution and ecological risk assessment of heavy metals in surface sediments from a typical plateau lake wetland, China

Surface sediment (0-15 cm) samples were collected from 31 different grid points throughout the Yilong Lake in April 2004. Samples were subjected to a total digestion technique and analyzed for As, Cd, Cr, Pb, Ni, Cu, and Zn in order to study spatial distribution characteristics based on Kriging method and assess their ecological risks posed by these heavy metals. Results showed that the mean concentrations of these heavy metals were lower than potential effect levels. Patches of higher heavy metal concentrations occurred in the inflow area of the Cheng River and northeast area nearby the road and railway. The higher concentrations of As and Cr also appeared in the east area (lake outlet), while the patches of lower concentrations were uniformly distributed at the southwest corner between Luosewan and Xiaoguoxi. The heavy metal loads such as As, Cd and Pb might come from the common sources due to industrial sewage and traffic pollution, while higher concentrations of Ni, Cr, and Zn in these sediments were dominated by parent rocks. However, Cu originated from both sources. Sediments with respect to As, Cd and Cu were grouped below the effect range low (ERL) at all sites, and with respect to Cr and Pb were grouped into the range from ERL to the effect range median (ERM) at more than 50% of sampling sites. The mean heavy metal toxic units in the Yilong Lake decreased following the order Pb > Cr > As > Ni > Zn > Cd > Cu, with higher contributions to the sum of toxic units of Pb, Cr and As.     

Contents of heavy metals in marine algae from Egyptian Red Sea coast

Seaweeds belonging to 14 different genera of Chlorophyta, Phaeophyta and Rhodophyta were analyzed to determine the levels of heavy metals in two areas of the Egyptian Red Sea coast. Among the trace metals analyzed, Mn and Zn showed the highest mass concentrations in the surface seawaters of the two studied areas. However, algae obtained from Suez area had the highest concentrations of the investigated heavy metals than those collected from Mars Alam area. Nevertheless, a high variability of the metal levels occurs among the studied algae and also between the investigated areas. Moreover, Zn was the most abundant metal in the seaweeds of the Suez area, while Pb was predominant in Mars Alam area in red and brown algae. L. farinosa had the highest average concentration factor of Zn in Suez (29161 fold), while it was 20091 fold in E. intestinalis at Mars Alam. The highest value of metal pollution index (MPI) was recoded in L. farinosa (22.0) at Suez. It represents 4.6 fold of that value recorded in L. farinosa at Mars Alam. Among green, brown and red algae in Suez, the highest values of MPI were recorded in Cladophora (mixed sub-species) and H. comuto (18.2 and 18.3), P. pavonia (16.2) and L. farinosa (22.1), respectively; while at Mars Alam, they were recorded in Cladophora (mixed sub-species) (6.6), P. pavonia (3.4) and L. farinosa (4.8), respectively.     

Contents of heavy metals in marine seaweeds from the Egyptian coast of the Red Sea

Seaweeds belonging to 14 different genera of Chlorophyta, Phaeophyta, and Rhodophyta were analysed to determine the levels of heavy metals in two areas of the Egyptian Red Sea coast. Among the trace metals analysed, Mn and Zn showed the highest mass concentrations in the surface sea waters of the two studied areas. However, algae obtained from the Suez area had higher concentrations of the investigated heavy metals than those collect in the Mars Alam area. Nevertheless, a high variability of the metal levels occurs among the studied algae and also between the investigated areas. Moreover, Zn was the most abundant metal in the seaweeds of the Suez area, while Pb was predominant in the Mars Alam area in red and brown algae. Liagora spp. had the highest average concentration factor of Zn in Suez (29 161-fold), while the average concentration factor in Enteromorpha spp. at Mars Alam was 20 091-fold. The highest Metal Pollution Index (MPI) value was recorded in Liagora spp. (22.0) at Suez. This represents a 4.6-fold higher value than that recorded in Liagora spp. at Mars Alam. Among green, brown, and red algae in Suez, the highest values of MPI were recorded in Cladophora spp. and Halimeda spp. (18.2 and 18.3), Padina spp. (16.2), and Liagora spp. (22.1), respectively; while at Mars Alam, the highest values of MPI were recorded in Cladophora spp. (6.6), Padina spp. (3.4) and Liagora spp. (4.8), respectively.     

Vertical Distribution and Inventories of 239,240Pu in Deep Sea Sediments of the Mediterranean Sea (Algerian Basin, Ionian Sea)

Deep-sea sediments collected in two areas of the Mediterranean Sea having different sedimentological characteristics have been analyzed to determine present concentrations and inventories of ^239,240Pu and to study the main mechanisms controlling them. Plutonium distribution in the deepest part of a submarine canyon (Taranto Valley, Ionian Sea) is compared to that obtained in an abyssal plain (north Algerian Plain). in the latter case, sedimentation is mainly due to the sinking of biogenic particles, while in the former lateral transport of terrigenous material along the slope of the canyon can significantly contribute to sediment accumulation on the bottom.

^239,240Pu surface concentration in the canyon ranged from 0.2 to 1 Bq kg^-1 (dry weight) and this was lower in the abyssal plain. in this area, plutonium was detectable only in the first 4 cm, while in the canyon it was present down to 11-15 cm. ^239,240Pu inventories are 3 Bq m^-2 in the plain and 45-60 Bq m^-2 in the canyon, indicating considerable input of terrigenous material towards the final part of the Taranto Valley.     

Trace metals in fish,sediment and water from the south west coast of the Arabian sea,Pakistan

Concentrations of ten metals (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn and Hg) in the edible muscle of Arius maculatus captured from eight different near‐shore and off‐shore sites off the south west coast of the Arabian Sea, Pakistan, were determined by atomic absorption spectrophotometry. Relevant water and sediment samples from the sites were also analysed for the metals. Zinc showed the highest metal concentration (6.763 μg/g, wet weight) in the muscle of the fish, while Mn and Hg showed lowest level (0.019 μg/g, wet weight). Of all the metals investigated, largest scatter (measured as σ) was observed for Zn (σ = 2.058 /μg/g) in fish muscle, for Fe and Mn in sediment (σ = 27481 and 44.50 μg/g) and for As in water (σ = 0.270 μg/L). The metal distribution data pertaining to water, fish and sediment were examined on the basis of simple metal correlations. The statistical study revealed that Ni, Cr, Pb and Cu had significant positive correlations (r > 0.830 at ρ = 0.01). The finding substantiated a trace metal concentration gradient in the area, thereby indicating that the local marine environment is contaminated by anthropogenic sources.     

Sources and Distribution of Heavy Metals in East China Sea Surface Sediments

Box cores and surficial sediments collected from the shelf, slope and Okinawa Trough of the East China Sea were analyzed for loss on ignition, and concentration and speciation of Al, Fe, Mn, Pb, Cd, Cu and Zn. in general, concentrations of these metals are higher in the inner shelf and lower in the midshelf, but the highest LOI, Cd and Mn levels are found in the Okinawa Trough. Spatial distributions of these metals in surficial sediments indicate that the Yangtze River is the major source for materials deposited in the inner shelf. the results of a six-stage sequential leaching experiment indicate that the fluvial input includes natural (e.g., Al and Fe) and anthropogenic (e.g., Pb) materials. the depletion concentration of these metals in the midshelf sediments reflects the dominance (～ 70%) of coarse, relict sand, while the enrichments in the inner shelf and the Okinawa Trough sediments are due to the fine grained, organic-rich sediments. the speciation of Mn in the sediments of the Okinawa Trough indicates that its distribution is diagentically or hydrothermally controlled.     

Sources and Distribution of Heavy Metals in East China Sea Surface Sediments

Box cores and surficial sediments collected from the shelf, slope and Okinawa Trough of the East China Sea were analyzed for loss on ignition, and concentration and speciation of Al, Fe, Mn, Pb, Cd, Cu and Zn. in general, concentrations of these metals are higher in the inner shelf and lower in the midshelf, but the highest LOI, Cd and Mn levels are found in the Okinawa Trough. Spatial distributions of these metals in surficial sediments indicate that the Yangtze River is the major source for materials deposited in the inner shelf. the results of a six-stage sequential leaching experiment indicate that the fluvial input includes natural (e.g., Al and Fe) and anthropogenic (e.g., Pb) materials. the depletion concentration of these metals in the midshelf sediments reflects the dominance (∼ 70%) of coarse, relict sand, while the enrichments in the inner shelf and the Okinawa Trough sediments are due to the fine grained, organic-rich sediments. the speciation of Mn in the sediments of the Okinawa Trough indicates that its distribution is diagentically or hydrothermally controlled.     

Particle size distribution and pollutants in road-deposited sediments in different areas of Zhenjiang,China

An understanding of road-deposited sediment (RDS) characteristics on an impervious surface is essential to estimate pollutant washoff characteristics and to minimise the impacts of pollutants on the water environment. A total of 62 RDS samples were collected from four different land-use types (commercial, residential, intense traffic and riverside park) in Zhenjiang City, China. The samples were fractionated into seven grain-size classes and analysed for particle size distribution and concentrations of pollutants. The samples are found to consist predominantly of fine particles (60–80%, <250 μm). The maximum mean concentrations of zinc, lead and copper were 686.93, 589.19 and 158.16 mg/kg, respectively, with the highest metal concentrations found in samples from the intense traffic area. The maximum mean contents of organic matter (12.55%), nitrogen (6.31 mg/g) and phosphorus (5.15 mg/g) were found in samples from the commercial area. The concentrations of heavy metals were highest in the smallest particle size fraction analysed (63 μm). The organic matter and nitrogen content generally increased with decreasing particle sizes in the <500-μm particle size range. The results also revealed that most of the total nitrogen (TN) is attached to the finer sediments and that to effectively reduce TN loads in particulates, treatment facilities must be able to remove the finer particles (down to 125 μm for TN).     

Distribution and speciation of heavy metals in Apulian coastal sediments

In the framework of the Interreg II Project Italy–Greece, distribution and speciation of trace metals in surface coastal sediments of Apulian regions were studied. A sequential extraction technique was used to determine the chemical association of heavy metals (Zn, Pb, Ni, Fe, Cr, Mn, Cu and Cd) with major sedimentary phases (acid soluble phases, easily reducible fraction and oxidizable matter). The relationship between the metals' content and the grain-size composition of the sediments was also considered: generally the elements resulted associated with the fine fraction, even if in some cases (Cu in the oxidizable phase) the opposite behaviour was observed. The studied area is not particularly polluted, except for some defined zones, as for example Brindisi's harbour. Speciation analysis revealed that the major part of the heavy metals are not easily mobilizable and bioavailable. Even in this case, there are some exceptions to the general behaviour: Cu and Pb in several samples are largely present in the oxidizable phase, which even if not immediately available can become a source of associated elements when redox conditions change.     

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.     

深圳蛇口渔港沉积物重金属分布及潜在生态风险评价

沉积物重金属污染对水生生态系统具有潜在危害.渔港是海岸带水环境的重要组成部分.对取自深圳蛇口渔港的10个表层沉积物样品中的As、Cd、Cu、Pb和Zn等典型重金属元素进行了分析,探讨了其空间分布;运用地积累指数法(Igeo)和生态危害指数法(RI),评价了表层沉积物中重金属的富集程度和潜在生态风险,初步探讨了其污染来源.结果表明:(1)蛇口渔港海域沉积物重金属Cu的污染十分严重,Zn和Pb污染较严重,其浓度均为港内>港口>港外;(2)渔港内沉积物重金属的富集达重度污染程度,潜在生态危害风险强.其中,又以Cu的富集程度最高,潜在生态危害风险最强;(3)渔港内Cu的污染,可能与电子工业废水的排放,以及渔业特有的防附着生物涂料有关.     

The accumulation levels of heavy metals (Ni,Cr, Sr, & Ag) in marine algae from southwest coast of India

In the context of use of marine algae as biological indicators of heavy metal pollution in coastal waters, six species of marine algae collected from the southwest coast of India were analysed for the levels of heavy metals (Ni, Cr, Sr, and Ag). Interspecies and interclass variations were determined on a spatial and temporal scale. The metal contents varied in the ranges, Ni: 0.20–21.06?µg?g^?1 (mean?=?10.13?µg?g^?1), Cr: non-detectable level (ND)–37.18?µg?g^?1 (mean?=?13.86?µg?g^?1), Sr: 2.19–103.90?µg?g^?1 (mean =?29.40?µg?g^?1), and Ag: ND–6.39?µg?g^?1 (mean?=?1.80?µg?g^?1). Ni and Cr contents were of similar magnitude to those reported for algae from polluted areas.     

Fractionation analysis of some heavy metals in sediments of the north-western part of the Red Sea,Egypt

Sequential extraction was used to study operationally determined chemical forms (exchangeable, carbonate, reducible metal, oxidisable metal and the residual fractions) of the metals Cd, Cu, Zn and Pb in sediments from 12 sample sites collected from the north-western part of the Red Sea, where improper recreational facilities have resulted in diverse impacts on the coastal environments fronting some of the recreation projects. The results showed that the average percentage of each phase was different among metal types; the residual binding fraction was the most important phase for binding Zn and to a lesser degree Cu. The reducible fraction was the second most important phase for Zn and Cu. For Pb, the fractions bounded to the residual fractions and the reducible phases are equal and exhibited the highest percentages. By contrast, the carbonate fraction was predominant for Cd. The percentages of Cd, Cu, Zn and Pb associated with the carbonate and exchangeable fractions, which are potentially the most harmful to the environment, were calculated and assessed at different sampling sites of the studied sediments. According to the Risk Assessment Code (RAC), the results reveal that Cd is the only metal that poses a high risk to the environment.     

Tracking the metal distribution in the tropical Valencia lake catchment: Soil, rivers and lake

In tropical areas, the relations between soil, rivers, and lakes are poorly understood as regard to the physicochemical transformation that occurs when solid materials are transferred among them. In order to ascertain the natural dynamics of Na, K, Mg, Ca, Al, Fe, Mn, Pb, Zn, Cu, Ni, Cr, and Co, as well as the perturbations by human activity, soils and sediments from a tropical catchment were studied. To accomplish the above mentioned objective, the Valencia Lake catchment was subdivided into three systems, i.e. soils, rivers and lakes. Original data and those previously published by Mogolló;n and Bifano (1994), and Mogolló;n et al. (1995, 1996) were used to establish the numerical relation between the average concentration in the three systems. The percentage labile fraction and metal distribution in different particle size fractions were studied in selected samples. A total of 410 samples was analysed.Lithology and topography are the main factors that differentiate the physicochemical characteristics of soils and sediments. Processes coupled with solid material transport from the upland to lowland area cause the increase of the HNO₃ (1M) extractable metal concentration, and of the percentage labile fraction, metal redistribution towards fine particle fraction. In spite of the tropical climate, the pedogenesis of exposed sediments and the transport along the river courses, have very low influence. Most of the transformations seem to occur during the soils – river transfer of materials. The carbonate precipitation in the lake causes further increase of metal concentration and the percentage labile fraction. The pollutant input increases metal concentration, the percentage labile fraction and the trend of accumulation toward fine particles.