[Conformity of trace element distribution in urban territory floodplain ecosystems]

Investigation was fulfilled in Central Belarus on several rivers and their floodplains being under impact of 9 cities. Sampling methods included sampling of humus layer of soil which were from the main floodplain facieses. Samples have been taken up-stream (profiles in 15 km, 10 km and 5 km), downstream (profiles in 1, 3, 7, 15, 25 km) and inside of the city (3...7 profiles with a step of 0,5...1 km). The total content of Cr, V, Mn, Ti, Ni, Co, Cu, Zr, Pb, Ba, Be, Y, Yb, Nb, Sc, Mo, and AG was analysed by the means of atomic-emission spectrometry. Additionally mobile compounds of Cd, Ni, Cr, Cu, Zn, Co were evaluated as IM HCl extraction with an atomic-absorption ending. Floodplain ecosystems of Central Belarus are specified by important lithological and geochemical diversity related to both natural factors, firstly, a diversity of geochemical composition of covering deposits from catchment area and technogenic factors such as melioration of catchment area and floodplain, channeling river-beds, hydrological regulation, chemical pollution. Associations of contaminants in floodplain soils are include such elements as Cr, Ni, Cu, Pb, Zn, Cd, Ag, but all of them are in frames of natural variation and nowadays they are not dangerous for utilization of floodplain ecosystem for pastures. First of all technogeochemical impact of cities to floodplain soils appears in the increasing of mobile metal compounds. Analyzes of these compounds enables to determine the beginning of pollution and such investigation has a first priority in the monitoring of floofplains. Considering a relative "eternity" of heavy metals being in landscape, a high accumulative abilities of humus layer in alluvial soils, observed growth of man-induced metal flow from urban areas it could be predicted the increasing of contrasting and wideening of polyelement anomalies in alluvial soils. Floodplain ecosystems inside and in vicinity of urban areas need integrated land management and monitoring