Sediment Parameters of Northwest Black Sea Shelf and Slope: Implications for Transport of Heavy Metals and Radionuclides

In June 1990, sediment cores were obtained from several locations in the Northwest Black Sea shelf and slope by a joint US/USSR scientific team aboard the survey vessel R/V VODYANITSKY. the goal of this investigation was to determine the distribution and levels of radioactivity resulting from the Chernobyl 1986 nuclear accident. the sediment was characterized for texture, mineral composition, redox state, heavy metals, and radionuclides. Correlations emerging from these data reveal paths of dispersal and transport of materials from river sources to deposition sites on the shelf and slope. Kaolinite in the clay mineral suite clearly reflects a dispersal pattern originating in the Danube River and progressing in an easterly direction across the shelf. Sand-size gypsum and the elemental heavy metals Zn, Cu, Cr, and Pb (probable industrial source) as well as the elements Al and Mg (probable terrigenous source) also show a dispersal pattern from the Danube station location in an easterly direction across the shelf. the dispersal direction indicated by these materials is not in conflict with recent existing notions concerning the hydrology of the Northwest Black Sea. Barium anomalies at a midshelf location may be related to operations in the Lebada oil fields situated updrift. Heavy mineral dispersal reflect the Danube and -Crimean Provinces established for the shelf and relate to terrestrial source areas. in addition, the heavy mineral monazite correlates with the radioactive Th 232 found most abundantly in the Crimean Province. Local anomalies of Mn, Fe and U in the sediment at station locations are related to redox (Eh) conditions and other factors. Cs^134/137 data, reported by Curtis and Broadway (1991), correspond to transport and dispersal patterns implicit in the mineralogic, anthropogenic indicators, and sediment characteristics of the study area.     

Partitioning of Cs-137 Between Sediment and Water From the Black Sea

As part of a joint USA/USSR Environmental Agreement to determine the distribution and concentration of Chernobyl radioactivity in the northwest Black Sea area, the sediment from eight stations was collected and analyzed to assess the ability of this material to adsorb radiocaesium. Batch tests were conducted in which Cs-137 tracer was added to mixtures of sediment and bottom water, with contact solutions ranging from 85 Bq ml^-1 to 1,760 Bq ml^-1. This work was done in an argon atmosphere at 9.5°C, which is the average temperature of the sediment. Isotherms were linear for all cores and distribution ratios (R_D) calculated from the slopes of the isotherms ranged from 660 to 1,660 ml g^-1. These isotherms fit a simplified Freundlich isotherm. Correlations of R_D to a number of sediment parameters describing texture and mineralogy were determined. A close relationship was observed between R_D for caesium and the percentage of illite contained in the samples.     

Partitioning of Cs-137 Between Sediment and Water From the Black Sea

Abstract

As part of a joint USA/USSR Environmental Agreement to determine the distribution and concentration of Chernobyl radioactivity in the northwest Black Sea area, the sediment from eight stations was collected and analyzed to assess the ability of this material to adsorb radiocaesium. Batch tests were conducted in which Cs-137 tracer was added to mixtures of sediment and bottom water, with contact solutions ranging from 85 Bq ml^?1 to 1,760 Bq ml^?1. This work was done in an argon atmosphere at 9.5°C, which is the average temperature of the sediment. Isotherms were linear for all cores and distribution ratios (R_D) calculated from the slopes of the isotherms ranged from 660 to 1,660 ml g^?1. These isotherms fit a simplified Freundlich isotherm. Correlations of R_D to a number of sediment parameters describing texture and mineralogy were determined. A close relationship was observed between R_D for caesium and the percentage of illite contained in the samples.     

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.     

Preliminary Caesium Data From A Cooperative Us/Ussr Monitoring Survey for Chernobyl Radioactivity in the Black Sea

In June 1990, scientists from the US Environmental Protection Agency's (EPA) Office of Radiation Programs (ORP), and the Woods Hole Oceanographic Institution (WHOI), travelled to Sevastopol in the Soviet Union to work with radioecologists and marine scientists from the USSR Institute of Biology of the Southern Seas (IBSS). the purpose of this cooperative programme was to conduct a monitoring survey for radioactivity in the northwestern Black Sea. Samples of sediment, surface and in-situ water, and biota were collected from fourteen stations for post-survey radionuclide analyses to determine levels of radioactivity in the Black Sea environment resulting from the Chernobyl nuclear power plant explosion and subsequent transport of radioactivity via the Dnepr and Danube rivers. This paper presents the preliminary data for caesium-137 and caesium-134 in sediment samples analyzed by the EPA/ORP. Caesium-137 was measured at four shallow (20–114 m) stations on the shelf near the mouth of the Dnepr and Danube Rivers, but was not detected in sediments from comparable depths at stations further off shore or in slope sediments at depths of 510–1288 meters. Caesium-134 was detected only in sediments from the shallow-water station nearest to the Danube River.     

Preliminary Caesium Data From A Cooperative Us/Ussr Monitoring Survey for Chernobyl Radioactivity in the Black Sea

In June 1990, scientists from the US Environmental Protection Agency's (EPA) Office of Radiation Programs (ORP), and the Woods Hole Oceanographic Institution (WHOI), travelled to Sevastopol in the Soviet Union to work with radioecologists and marine scientists from the USSR Institute of Biology of the Southern Seas (IBSS). the purpose of this cooperative programme was to conduct a monitoring survey for radioactivity in the northwestern Black Sea. Samples of sediment, surface and in-situ water, and biota were collected from fourteen stations for post-survey radionuclide analyses to determine levels of radioactivity in the Black Sea environment resulting from the Chernobyl nuclear power plant explosion and subsequent transport of radioactivity via the Dnepr and Danube rivers. This paper presents the preliminary data for caesium-137 and caesium-134 in sediment samples analyzed by the EPA/ORP. Caesium-137 was measured at four shallow (20-114 m) stations on the shelf near the mouth of the Dnepr and Danube Rivers, but was not detected in sediments from comparable depths at stations further off shore or in slope sediments at depths of 510-1288 meters. Caesium-134 was detected only in sediments from the shallow-water station nearest to the Danube River.     

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.     

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.