Heavy metals and carbon isotope concentrations in recent Baltic Sea sediments

Recent sediment cores of the western Baltic Sea were analyzed for heavy metal and carbon isotope contents. The sedimentation rate was determined from radiocarbon dates to be 1.4 mm/yr. The 'recent age' of the sediment was about 850 yr. Within the upper 20 cm of sediment, certain heavy metals became increasingly enriched towards the surface; Cd, Pb, Zn and Cu increased 7-, 4-, 3- and 2-fold, respectively, whereas Fe, Mn, Ni and Co remained unchanged. Simultaneously, the radiocarbon content decreased by about 14 per cent. The enrichment in heavy metals as well as the decrease in the 14C-concentration during the last 130 ± 30yr parallels industrial growth as reflected in European fossil fuel consumption within that same period of time. The near-surface sediments are affected by residues released from fossil fuels at the rate of about 30 g/m**2 yr for the past two decades. The residues have a pronounced effect on the heavy metal and carbon isotope composition of the most Recent sediments allowing estimates to be made for sedimentation, erosion and heavy metal pollution.

Concentrations of suspended matter and heavy metals in melted ice- and snow water from the Barents Sea

In September-October 1998, during Cruise 14 of R/V Akademik Fedorov to the Barents Sea, in the region of 82° N between the Spitsbergen and Novaya Zemlya archipelagos samples of snow and ice were collected within four polygons. By means of atomic absorption with an electothermal atomizer (onboard the ship) in filtered (dissolved form) and unfiltered (sum of dissolved and particulate forms) samples of snow melt and ice melt concentrations of Fe, Mn, Cu, Cr, Ni, Co, Pb, and Cd were determined in order to estimate level of potential contamination of snow and ice with these metals. Excluding data on Ni, Cd (and probably Cu) in ice that were regarded to be unsatisfactory because of probable contamination of the ice samples during drilling concentrations of all the elements in snow and ice of the northern part of the Barents Sea appeared to be close to their background values or below. An attempt to identify the main sources of metal supply to snow from the atmosphere by comparison of ratios of metal particulate form to total content in snow of the Barents Sea and the same ratios in snow samples from clean regions of Finland and from contaminated areas of the Kola Peninsula showed that aerosols in the area of the expedition were supplied into the Barents Sea atmosphere from different sources, both natural and anthropogenic.

Magnetic properties and heavy metals at DSDP Hole 83-504B

We report measurements of magnetic intensity, inclination, initial susceptibility, Koenigsberger's ratio, saturation magnetization, and Curie temperatures of 68 basalt samples from the Leg 83 section of Hole 504B. As in the upper part of the hole, reversely magnetized units predominate. Intensities of natural remanent magnetization vary widely, but the range of variation is an order of magnitude less than in the upper part of the hole. This and the other properties measured indicate that the magnetic characteristics of basalts from Hole 504B have been strongly affected by hydrothermal alteration, particularly in the deeper, Leg 83 section. The alteration states of the magnetic samples were studies using Xray diffraction, electron microprobe, X-ray fluorescence, and ion coupled plasma. Our results suggest three alteration zones in Hole 504B: a low-temperature zone (274.5-890 m) and two high-temperature zones (890-1050 m and 1050- 1350 m), differing in the number of veins observed in the samples and presumably differing in the volumes of hydrothermal fluids which reacted with the basalts.

Lead and cadmium in the Weser Estuary and the German Bight: Correlations between bacteria populations, heavy metals and organic carbon

Organic carbon, lead and cadmium contents of 20 sediments were determined and compared with the colony counts of anaerobic heterotrophic, anaerobic nitrogen fixing, chitinoclastic and cellulolytic bacteria. Organic carbon content, which is dependent on the sediment type, was positively correlated with lead and cadmium as well as with colony counts of all 4 physiological groups of bacteria. Even the sediments with the highest concentrations of 251.7 ppm Pb and 3.1 ppm Cd showed no reduction in their colony counts. From 2 different sediment sampIes with lead contents of 140 ppm and 21 ppm lead tolerance of the aerobic heterotrophic bacteria was investigated. However, no significant difference in lead tolerance of the 2 heterotrophic populations was found. Water from 6 stations was analysed for dissolved and particulate organic carbon, lead and cadmium. Dissolved lead concentrations were in the range of 0.2-0.5 µg/l and the particulate lead contents were between 0.05 and 4.3 µg/l. The concentrations of total lead for the stations off-shore were only one order of magnitude from the concentrations of the near-shore stations. The same phenomenon was observed for dissolved cadmium (0.02 - 0.25 µg/l) and particulate cadmium (0.003 - 0.15 µg/I) concentrations. Correlations between dissolved (1.6 - 10.8 mg/I) and particulate organic carbon (0.25 - 1.53 mg/I) with dissolved and particulate lead or cadmium were not found.

Concentrations of dissolved and particulate heavy metals in waters above the northwestern slope of the Paramushir Island (Sea of Okhotsk)

Distributions of Mn, Fe, Cu, Cd, Cr, Co and Ni in sea water are investigated (42 samples, dissolved and particulate forms) in the vicinity of the underwater gas vent field on the northwestern slope of the Paramushir Island. While regular background distributions of the elements occur in the shore zone, there is a column of elevated concentrations of particulate matter, particulate Mn, and dissolved Mn, Fe, Cu, Cd, Cr, Co and Ni that coincides with location of the gas plume. This column can be traced as high as 780 m above the bottom. High metal concentrations in water of the plume are attributable to physico-chemical concentration at the phase interface; the source of elevated mineral concentrations is obviously flux of dissolved minerals from interstitial waters, which extends to considerable distances in vertical direction.