Elemental composition of suspended particles from the surface waters of Lake Baikal in the zone affected by the Selenga River

The elemental composition of suspended particles in surface waters of Lake Baikal has been studied by ICP MS along a transect of the zone affected by the Selenga River. The amount of terrigenous suspension in water was estimated from Al content, which decreases in a saltatory manner along the transect: 6.5-8.3 km offshore it decreases by an order of magnitude; 11-14 km offshore, by other 20 times; in the pelagic zone it remains almost unchanged. During the study period (late June 2001), the distribution limit of suspension from the Selenga River in the lake's surface waters lays 11-14 km offshore. It has been found that pelagic suspension is more than 20 times richer in Ca, P, Zn, Cu, Ni, Sn, Mo, Bi, S, and Cd than littoral one (6.5 km offshore) in the zone affected by the Selenga River. This is mainly due to fine suspension (<1.2 mu m), which was considerably richer in Ca, P, Zn, Cu, Ni, Sn, Mo, Sb, and Cd than coarser ones in the river. Fine suspension in Lake Baikal, both in the zone affected by the river and in the pelagic zone, is considerably (2-35 times) richer in most elements, except for typical terrigenous ones, than river one. This suggests that element enrichment takes place in the lake, probably owing to bioaccumulation and chemisorption. These processes may be affected by additional factors, because fine suspension from the zone affected by the river differs significantly from pelagic one in elemental composition. (C) 2010, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.