The border Polish-Czech sector of Upper Odra river is located between Chałupki Bohumin towns and the Olza river mouth (km 20,0-km 28,0). The unique meanders appear here, where the intensive dynamic erosion-sedimentation processes take place. Except for natural factors influencing the river-bed changes also human activity appears here. It concerns development of the Odra valley partly by bridges, embankment and protection of channel banks through seawalls and groins. During last 200 years the Odra river has varied its course. In 1967 and 1997 on account of the big freshets two Odra channel breaks followed i.e. in region of meander No. IV (1967) and No. I (1997). In consequence it formed here the new branches, which are gradually from water flow. At present in the old Odra river bed at meander No. IV water doesn't flow, and the old Odra river of meander No. I is silted up and bushed. Studies of authors showed that thickness of deposits in the old Odra river meander No. I is 1.0 m. There are mainly cohesive and semi-cohesive sediments derived from the Upper Odra course (wash load and suspended load) and from bank erosion, mainly the left Polish bank (km 20.7-km 21.3), and the Czech bank (km 21.0-km 21.2). These cohesive sediments contain the following fractions: clay (grain size d<0.002 mm) 12%, dust (d=0.002- 0.05 mm) 58% and sand (d=0.05-2.0 mm) 30%. Solid fractions d<0,02 mm accumulate best contaminants, and their amount in Odra deposits is about 87%. These deposits cumulate among others microelements: Ag, As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sr, V, Zn, Aromatic Polynuclear Hydrocarbons (APH) at al. Contaminated sediment transport is associated with hydraulic conditions of stream, morphology of river channel and with consolidation of soil. On the base of field studies and calculations it was discovered that fractions less than 0.2 mm are transported at flow velocities below 0.45 m/s. Upper Odra deposits in Chałupki are investigated systematically since the beginning of nineties last century. Measurements have been carried out by the State Institute of Geology, and reports are published by Governor's Inspectorate of Environment Protection in Katowice. Analysis of these study results show that: in period 1991-98 contents of bar and zinc exceeded 200 ppm, in 2002 content of lead was 50 ppm, bar 300 ppm, cadmium less than 0.5 ppm, and APH 3.6 ppm, in 2003: arsenic 7 ppm, cadmium less than 0.5 ppm, zinc 162 ppm, chromium 19 ppm, and APH 2 ppm, in 2004: bar 659 ppm, cadmium 0.5 ppm, lead 60 ppm, copper 40 ppm, mercury 0.38 ppm, and APH 7.7 ppm, in 2005: arsenic 60 ppm, and APH 53.65 ppm. It was observed that on the inlet sector to meander No. I the islands were created formed by non-cohesive sediment deposited at subsoil (gravel and sand), and by semi cohesive sediment deposited at crown of layer (sand mud). Sediment from these islands also contains contaminates (microelements at al.). As well as sediment deposited in the old Odra river bed of meander No. I and IV, and soils forming the islands do not threat flora and fauna. However, during the floods sediment has been activated and has been source of contaminants for water and living organisms.
