Reactivity of particulate element concentrations: apportionment assessment of suspended particulate matter sources in the Upper Rhône River,France

Journal of Soils and Sediments - Suspended particulate matter (SPM) transport through rivers is a major vector of nutrients and pollutants to continental shelf areas. To develop efficient sediment...     

The distribution of dissolved and particulate mercury in three Siberian estuaries and adjacent Arctic coastal waters

Dissolved and particulate mercury distributions were determined in the three largest Siberian rivers and in adjacent Arctic coastal waters during two cruises. Water samples were collected in the Lena River and its mixing zone in the Laptev Sea in September 1991, and in the Ob and Yenisei Rivers and the adjacent Kara Sea in September 1993. Average total dissolved Hg concentration was 5.0 pM in the Lena River, 2.8 pM in the Ob River and 1.5 pM in the Yenisei River. Mercury content of suspended particulate matter was low, averaging 0.17 mg kg^?1 in the Lena and 0.05 mg kg^?1 in the Ob and Yenisei Rivers. These concentrations are lower than those observed in other world rivers affected by local input of man-made origin. In the estuarine mixing zones, higher concentrations of dissolved and particulate Hg which may originate from the spring flood were found. The carbon cycle is apparently a driving mechanism for Hg distribution in Arctic coastal waters. Particulate Hg content was positively correlated with the content of organic matter of the particles. In the Kara Sea, uptake by phytoplankton is suspected to be responsible for the increase in particulate Hg levels. Mercury fluxes from the three rivers to the Arctic Shelf are estimated and compared to direct atmospheric inputs.     

Lead concentrations in lichens from the Canadian high arctic in relation to the latitudinal pollution gradient

Measuring deposition of anthropogenic Pb is essential for quantifying global patterns of pollution dispersion. Concentrations of Pb, however, have only rarely been measured in lichens collected from the High Arctic. In this study we used flameless atomic absorption spectrophotometry to determine that the average Pb content in five lichen species from several remote sites on Ellesmere Island was 2 µg g^?1 dry wt. These are among the lowest Pb concentrations that have ever been recorded in Arctic plants. Literature data were combined to establish a latitudinal gradient showing decreasing Pb concentrations in lichens with increasing latitude throughout Canada.