PHYTOINDICATION AND PHYTOREMEDIATION OF THE POLLUTED WITH HEAVY METALS SOIL IN SOUTH KAZAKHSTAN

Abstract

Soil pollution with heavy metals remains one of the priority environmental problems of Southern Kazakhstan. It is found that due to the processes of water and wind erosion, the content of lead and cadmium ions in the soils of the Shymkent districts adjacent to the storage site of lead-zinc slags exceeds the MPC by up to 453.3 ± 34.7 times. The main purpose of the research was to study the possibility of phytoindication and phytoremediation of soils of Southern Kazakhstan contaminated with heavy metals. It was revealed that in the arid climate of southern Kazakhstan, the highest concentration of heavy metal ions accumulates in the upper horizons of soils, which are the root layer for most types of vegetation of the ephemeroid semisavanna. The most phyto-indicative indicator of the level of soil contamination with heavy metals is the phytocenotic composition of the plant community and the projective covering of soils with vegetation. Plant communities of different zones of soil contamination with heavy metals are not the same both in the number of species and in the phytocenotic composition of groups, while the proportion of erosiophilic and ruderal species with a predominance of perennial plant species is growing in the direction of the toxic gradient growth. In addition, in the gradient of pollution growth, there is a decrease in the proportion of mesophytic and an increase in xerophytic ecological groups of plants. It has been established that the meager and stable species composition of the vascular plant community of the impact zone of pollution is justified by the presence of certain resistance mechanisms in these species due to mechanical, growth barriers and the ability of the plant organism to neutralize excessive amounts of heavy metal ions in the form of water-insoluble salt deposits in the intercellular space. The technology of phytoconservation of dusty surfaces of toxic waste of polymetallic production of JSC "Yuzhpolymetal" has been developed, which provides a projective coating of the preserved surface by 85-100% over two years of use.