The Estimation of the Ecological Condition of the City Environment by Methods of Phytoindication (as Applied to the Vasileostrovsky District of St. Petersburg)

The project aimed to use results of contamination of city vegetation with heavy metals and sulphur compounds as the basis for analysing the integral response of trees and shrubs to contamination, through a complex method of phytoindication. The results were used to draw up recommendations on pollution reduction in the city and to develop the method of phytoindication as a means of monitoring environmental pollution in St. Petersburg and other large cities. Field investigations were carried out in August 1996, and 66 descriptions of green areas were made in order to estimate the functional state of plants in the Vasileostrovsky district. Investigations of the spectrum reflecting properties of plants showed considerable variation of albedo meanings of leaves under the influence of various internal and external factors. The results indicated that lime trees most closely reflect the condition of the environment. Practically all the green areas studied were in poor condition, the only exceptions being areas of ash trees, which are more resistant to environmental pollution, and one lime-tree alley in a comparatively unpolluted street. The study identified those types of trees which are more or less resistant to complex environmental pollution and Ms. Terekhina recommends that the species in the present green areas be changed to include a higher number of the more resistant species. The turbidimetric analysis of tree barks for sulphates gave an indication of the level and spatial distribution of each pollutant, and the results also confirmed other findings that electric conductivity is a significant feature in determining the extent of sulphate pollution. In testing for various metals, the lime tree showed the highest contents for all elements except magnesium, copper, zinc, cadmium and strontium, again confirming the species' vulnerability to pollution. Medium rates of concentration in the city and environs showed that city plants concentrate 3 times as many different elements and 10 times more chromium, copper and lead than do those in the suburbs. The second stage of the study was based on the concept of phytoindication, which presupposes that changes in the relation of chemical elements in regional biological circulation under the influence of technogenesis provide a criterion for predicting displacements in people's health. There are certain basic factors in this concept. The first is that all living beings are related ecologically as well as by their evolutionary origin, and that the lower an organism is on the evolutionary scale, the less adaptational reserve it has. The second is that smaller concentrations of chemical elements are needed for toxicological influence on plants than on people and so the former's reactions to geochemical factors are easier to characterise. Visual indicational features of urban plants are well defined and can form the basis of a complex "environment - public health" analysis. Specific plant reactions reflecting atmospheric pollution and other components of urbogeosystems make it possible to determine indication criteria for predicting possible disturbances in the general state of health of the population. Thirdly the results of phytoindication investigations must be taken together with information about public health in the area. It only proved possibly to analyse general indexes of public health based on statistical data from the late 1980s and early 1990s as the data of later years were greatly influenced by social factors. These data show that the rates of illness in St. Petersburg (especially for children) are higher than in Russia as a whole, for most classes of diseases, indicating that the population there is more sensitive to the ecological state of the urban environment. The Vasileostrovsky district had the second highest sick rate for adullts, while the rate of infant mortality in the first year of life was highest there. Ms. Terekhina recommends further studies to more precisely assess the effectiveness of the methods she tested, but has drawn up a proposed map of environmental hazard for the population, taking into account prevailing wind directions.

Lake Ladoga: Water Resources for the Sustainable Development of North-Western Russia and Finland

The aim of this project was to evaluate the present state and possible changes of water resources in Lake Ladoga and its drainage basin for the purposes of the sustainable development of North-Western Russia and Finland. The group assessed the state of the water resources in quantitative and qualitative terms, taking the system of sustainable development indicators suggested by the International Commission on Sustainable Development as a basis for assessment. These include pressure indicators (annual withdrawals of ground and surface water, domestic consumption of water per capita), state indicators (ground water reserves, concentration of faecalcoliform in fresh water, biochemical oxygen demand), and response indicators (waste-water treatment coverage, density of hydrological networks). The group proposed the following additional indicators and indices for the complex evaluation of the qualitative and quantitative state of the region's water resources: * Pressure indicators (external load, coefficient of anthropogenic pressure) * State indicators and indices (concentrations of chemicals in water, concentrations of chemicals in sediments, index of water pollution, critical load, critical limit, internal load, load/critical load, concentration/critical limit, internal load/external load, trophic state, biotic indicators and indices) * Response indicators (discharges of pure water, polluted water, partly treated water and the ratio between these, trans-boundary fluxes of pollutants, state expenditure on environmental protection, human life span) The assessment considered both temporal and spatial aspects and produced a regional classification of the area according to the index of water pollution. Mathematical models were developed to describe and forecast the processes under way in the lake and can be used to estimate the influence of climatic changes on the hydrological regime, as well as the influence of anthropogenic load on the trophic state of Lake Ladoga and to assess the consequences of accidental discharges of polluting admixtures of different kinds into the lake. The results of this mathematical modelling may be of use to decision-makers responsible for the management of water resources.