The ecological-geochemical evaluation of urban soils includes quantification of changes in their physical and chemical properties,and assessment of the effect of these changes on priority pollutants (including heavy metals) accumulation.For many cities an extremely high technogenic concentration of lead is characteristic.Therefore,the purpose of our work was to study the dynamics of soil properties,to reveal spatial-temporal trendsin soil pollution by lead,to estimate the mean annual rate of the increase in its content and to forecast the time of its doubling in soils.The work is based on the results of soil-geochemical serveys performed by the authors in the Eastern district of Moscow in 1989 and 2005.The study area was located in its southern,most contaminated part.For the choice of sample sites,the approaches proposed by N.S.Kasimov (1995) and based on natural-functional zoning of a territory were used.Two upper soil horizons were sampled:0-15 and 15-30 cm,in total 202 samples were collected.Natural soils of Meshera lowland were accepted as reference ones.The total lead content in soils was determined by atomic absorption spectroscopy,physical and chemical properties of soils-by routine methods.The analytical data have been grouped according to functional zones of the study area,and processed statistically in packages Statistica 7 and SPlus.The region belongs to the southern taiga landscapes of Meshera fluvioglacial lowland.Urban soils have preserved few features of natural soddy-or boggy-podzolic soils.Strongly acid and acid reaction of initial soils was replaced by weakly acid,neutral and alkaline.At present,the mean pH values are equal to 7.8 in urban soils.The dynamics of pH for the period of 1989-2005 reveals its further increase.In comparison with the reference soils,the content of organic matter and elements of plant nutrition (N,and P) is 3.7-6,3 times higher in urban soils.Concentrations of K,Fe and Mn are higher as well.The soil texture became heavier,the exchange capacity increased by 2.6-3.8 times.All these processes are responsible for the formation of alkaline and sorption geochemical barriers in the surface layers of soils promoting slacking of lead migration and formation of its technogenic pollution aureoles.Over the territory of the Eastern district three extensive and contrasting technogenic aureoles of lead pollution have been found.The northwestern aureole with an almost triple increase in lead concentration for 16-years period (about 170 mg/kg up to 500 mg/kg) is the most expressed and has a maximum accumulation in the 0-15 cm layer.In comparison with the reference soils,the lead concentrations in soils of the study area are 4 and 9.5 times higher in 1989 and 2005,respectively.For the 1989-2005 period the level of lead pollution of urban soils has increased on the average by 2.4 times.In terms of lead pollution,soils of various functional zones may be arranged in a following sequence:highways and industrial zones ≥ old residential blocks > agricultural landscapes > streets > recreational zone > blocks with new buildings.The highest rate of increase in lead content in a surface soil layer for the 16-years period was 5-20 mg/kg/year in the northwestern pollution aureole.The southeastern and central ones have a smaller rate-2-6 mg/kg/year.The peripheral parts of pollution aureoles are characterized by a low rate,namely,1-2 mg/kg/year.Basing on the average rates of lead concentrations increase,time of their doubling was forecasted for the surface soil layer.According to our estimates,it would not exceed 30 years in strongly contaminated zones,in the streets and recreational zone within the study area,it is dose to 42 years,and in soils of new quarters it would be 55 years.Using the 《regression trees》 method,the contributions of main geochemical factors on lead accumulation in soils of the Eastern district of Moscow have been specified.A dendrogram derived from the 2005 data has been used to assess lead accumulation at the level of soil propertiesparameters recorded in 1989.It is found out,that 40 % of increase in lead concentration for 16-years period are related to the changes of physical and chemical soil properties responsible for the growth of their exchange capacity.