The Fifth Conference “ N uclear Science and Its A pplication”, 14-17 October 2008
ESTIMATION OF ACTIVITY OF MICROBIOTA OF SALINE SOILS
STRONGLY CONTAMINATED BY CHLOROORGANIC COMPOUNDS
WITH THE USE OF TRITIUM LABELED PCBS
A. A. KİMİ, G.T. DJURAEVA1, J.A. DAD AKHANOV 1. G.I. DJUMANIYAZOVA 2, P.V. ZINOVEV.2, KH.T. YADGAROV2
1 Institute of Nuclear Physics, Uzbekistan Academy of Sciences, Tashkent, Uzbekistan; 2Institute of Genetics and Experimental Biology of Plants, Uzbekistan Academy of Sciences, Tashkent, Uzbekistan
The objective o f our study was investigation of destructive activity of saline soils microbiota, long-term contaminated by persistent chloroorganic compounds. The estimation of ability soil microbiota to destroy persistent chloroorganic compounds allows to determine the possibility opportunity of self-remediation of soil due to activity of own microbiota.
We investigated series of soil samples from various regions with various levels o f salinity and with various contents of persistent chloroorganic compounds. The ability of soil samples microbiota to destroy tritium labeled polychlorinated biphenils (PCBs) was investigated. Aliquots 0,1 mg tritium labeled PCBs were introduced in hexane solution into the 200 mg aliquots o f soil samples. Then soil samples were dried up to full removal o f hexane and wetted by distillate. Samples were incubated at room temperature with supporting constant soil humidity. The same soil samples sterilized in the autoclave were used as references. After two and four months we selected aliquots from experimental samples, extracted PCBs by mixture hexane : acetone (1:1) and measured radioactivity of extracts.
Also the ability o f soil samples microbiota to destroy tritium labeled hexachlorocyclohexane (HCCH) was investigated. HCCH was introduced in soil samples. Samples were incubated at room temperature with supporting constant soil humidity. The same soil samples sterilized in an autoclave were used as control. After two and four months we selected aliquots from experimental samples, extracted HCCH by hexane and analyzed extracts by gas chromatography of chromatograph Agilent Technologies 6890N with microECD detector.
We found some variants of microbiota activity. First group of soil samples contain soil microbiota unable to destroy HCCH and PCBs. Samples o f soil samples contain microbiota with moderate destructive activity, in which destruction HCCH and PCBs for 4 months occurs in an appreciable degree. And third group of soil samples contain microbiota with high destructive activity.
Besides we carried out investigations of efficiency of various variants o f stimulation PCB- destructive activity o f microbiota o f soil samples, strongly contaminated by persistent chloroorganic compounds. We had been investigated efficiency of application o f biofertilizer developed in laboratory of soil microbiology of Institute o f Microbiology Academy of Sciences of Uzbekistan, for stimulation o f PCB-destructive activity of microbiota o f soil samples, strongly contaminated by persistent chloroorganic compounds. It was found, that maximal destruction o f tritium labeled PCBs occurs in samples with introduced biofertilizer.
The obtained data indicate that in various saline soil samples the destruction o f tritium labeled PCBs occurs with various speed - after 4 months in soil samples remains from 4 3 % up to 74 %
o f introduced tritium labeled PCBs radioactivity. It is obvious, that for various sites of soils it is necessary to select various variants for destruction o f persistent chloroorganic compounds.
The received results allow to predict self-remediation of soils with active microbiota. Besides on the basis o f the received data it is possible to determine optimal strategy of bioremediation
Section IV. A pplication O f Nuclear T echnologies In Industry, M edicine A nd Agriculture 128
