论文部分内容阅读
The pollution of the cultivated areas by heavy metals has negative influence on quality of the food and on human health.The main sources of heavy metals in the cultivated area are mineral fertilizers,pesticides,some types of soil amendments.Many types of agrochemicals has low content of heavy metals and officially accepted for agriculture,however,because agrochemicals are applied every year,heavy metals from these sources are accumulated in soil.In the result of this accumulation the level of heavy metals are increased and finally soil may be classified as chemically degraded soil.Usually for purification of the contaminated area the technology with using of acid washing are used.But this technology is very expensive and cant be used on large scale.Therefore the bioremediation(using of the special plants for adsorption of the heavy metals form soil)was elaborated.Considering that heavy metals usually have low mobility and toxic effect on the cultivated plant the bioremediation require long time procedure for cleaning of the polluted soils.The efficiency of bioremediation can be increased if mobility of heavy metals and resistance of cultivated special plants against pollution will be increased.Our laboratory and greenhouse investigation showed that monosilicic acid can regulate the heavy metals(Zn,Pb,Cd,Cr)mobility.Low concentration of the monosilicic acid forms water soluble complexes with heavy metals.In the result the total mobility of the heavy metals were increased on 30-150%.The effect was depending on monosilicic acid concentration and type of heavy metals.In this situation the cultivated plants increased the adsorption of heavy metals on 30-250%.High concentration of the monosilicic acid in the soil solution results in reduction of the heavy metals mobility on 40-300%.In this situation the adsorption of heavy metals by plants were decreased on 2-3 times.The optimization of the Si nutrition of the cultivated plants(barley,wheat,pea)also increased the plant resistance to heavy metal toxicity.The obtained data give possibility to elaborate new technology for increasing the bioremediation efficiency on 2-3 times by using of the Si fertilizers or Si-rich soil amendments.The elaborated technology also included the localization of the polluted area.This technology can be adapted for any region and any soil-climatic conditions.Various forms of Si can be used in the elaborated technology,because special methodology for characterization of the Si status was elaborated as well.