Polycyclic aromatic hydrocarbons in the Arctic: Ob and Yenisei estuaries and Kara Sea shelf

Suspended matter (SM) and surface sediments were analysed for polycyclic aromatic hydrocarbons (PAH) throughout the Ob and Yenisei River estuaries and in the Kara Sea in order to evaluate the contamination of Arctic shelves by these two major Siberian rivers. PAH concentrations were extremely low, among the lowest measured up to now in the Arctic region. Particle-associated PAH were in many cases non-detectable. A total PAH maximum value of 3.2 ng l(-1) was found in surface waters. In surficial sediments, they spanned a range from 24 to 115 ng g(-2) in the Ob River, from 40 to 131 ng g(-2) in the Yenisei and from 16 to 94 ng g(-2) in the Kara Sea. Compositional features revealed a contribution of detrital material eroded from soils of the drainage basins and inputs from airborne pyrolytic PAH emitted at lower latitudes and from industrial complexes in Siberia. Particulate and sedimentary PAH distributions were highly variable both in type and concentration. The Ob and Yenisei estuaries are geographically large features where hydro-dynamical and sedimentary processes are complex. As a consequence, inhomogeneities-in the form of patch-structures-develop and make it difficult to resolve the fate of riverborne constituents based on ship measurements only. Remote sensing in conjunction with oceanographic observations may provide further guidance to study large river systems. (C) 1999 Academic Press.