Sources and seasonality of polycyclic aromatic hydrocarbons transported to Alert, Canadian Arctic

A probabilistic function (integrated source contribution function, ISCF) based on backward air mass trajectory calculation was developed to track sources and atmospheric pathways of polycyclic aromatic hydrocarbons (PAHs) to the Canadian High Arctic station of Alert. In addition to the movement of air masses, the emission intensities at the sources and the major processes of partition, indirect photolysis, and deposition occurring on the way to the Arctic were incorporated into the ISCF. The predicted temporal trend of PAHs at Alert was validated by measured PAH concentrations throughout 2004. The PAH levels in the summer are orders of magnitude lower than those in the winter and spring when long-range atmospheric transport events occur more frequently. PAHs observed at Alert are mostly from East Asia (including Russia Far East), North Europe (including European Russia), and North America. These sources account for 25, 45, and 27% of PAHs atmospheric level at Alert, respectively. Source regions and transport pathways contributing to the PAHs contamination in the Canadian High Arctic vary seasonally. In the winter, Russia and Europe are the major sources. PAHs from these sources travel eastward and turn to the north at approximately 120°E before reaching Alert, in conjunction with the well- known Arctic haze events. In the spring, PAHs from Russia and Europe first migrate to the west and then turn to the north at 60°W toward Alert. The majority of PAHs in the summer are from northern Canada where they are carried to Alert via low- level transport pathways. In the fall, 70% of PAHs arriving at Alert are delivered from North American sources.

Polyaromatic hydrocarbons in sediments from the Barents and White Seas

Polycyclic aromatic hydrocarbons (PAHs) are common environmental contaminants which can be derived from anthropogenic sources, such as combustion and discharges from extraction and transport, and natural processes, including leakage and erosion of fossil carbon. Natural PAH sources contribute, along with biological activities and terrestrial run-off, to the organic carbon content in sediments.The Barents Sea region is far from many anthropogenic sources of PAH, but production and trans-shipment of hydrocarbons is increasing. We present data for polycyclic aromatic hydrocarbon (PAH) concentrations in bottom sediments from 510 stations in the Barents and White Seas, and along the northern coast of Norway.

Composition of organic matter in bottom sediments from the Antarctic sector of the Atlantic Ocean

We identify geochemical features of sedimentary organic matter in various morphostructural zones of the Antarctic sector of the Atlantic. We present background geochemical organic parameters for shelf and deep-sea sediments from the Weddell and Scotia Seas and the Bransfield Strait. Geochemical organic parameters are good indicators of environmental and facial variations in sediments and could be used for environmental monitoring of the World Ocean.

(Table 2) Composition of polycyclic aromatics in bottom sediments from the Weddell Sea

Distribution, composition and genesis of organic matter in recent bottom sediments of the Weddell Sea (Western Antarctic) are discussed. Geochemical background levels of bitumen, organic matter, and polycyclic aromatics in the sediments are respectively 0.01-0.1%, 0.003-0.005%, and 0.0001-0.0002%. Deviations from the background level, probably caused by secondary processes, are found. Organic matter has characteristic properties resulting from distinctive character of aquatic biota organic matter, from which it has been formed.

Hydrocarbons in water, suspended matter, and bottom sediments of the White Sea

Data are presented on concentration and composition of aliphatic and polycyclic aromatic hydrocarbons (HC) in water, suspended matter (collected with a Juday net and by a separator), and in bottom sediments of the White Sea. It was found that during the last years the level of aliphatic HC concentrations in waters of the White Sea (aver. 18 µg/l) practically did not change and was comparable with average concentrations in shelf areas of the World Ocean. In water and bottom sediments distribution of HC is determined by discharge of river marginal filters. Here sedimentation of the bulk of anthropogenic HC occurs. That is why a grain-size controlling factor is not active in the zone of the river depocenter (in particular, of the North Dvina River). The same reasons most probably may explain differences in degree of geochemical relationships between contents of TOC and HC in suspended matter and bottom sediments. After passing through marginal filters natural HC are dominant in all migration forms.

Contents of hydrocarbons in waters and bottom sediments of the southwestern Amur Bay (Sea of Japan) in April 2005

Abundances and compositions of aliphatic hydrocarbons (AHC) and polyaromatic hydrocarbons (PAH) were investigated in water and bottom sediments of the southwestern Amur Bay, Sea of Japan. Water contained 0-129 ?g/l AHC (average 42.2 ?g/l) and 5-85 ng/l PAH (average 18 ng/l). Bottom sediments contained 168-2098 ?g/g AHC and 7.2-1100 ng/g dry mass PAH. It was shown that input of anthropogenic hydrocarbons is better recorded by molecular markers than by distribution of AHC and PAH concentrations. Discovery of elevated hydrocarbon concentrations in the bottom water layer suggests that bottom sediments induced secondary contamination of the water body.