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CORCIMARU, Serghei; TĂNASE, Ana; COZMA, Vasile; RASTIMESINA, Inna; POSTOLACHI, Olga; SÎRBU, Tamara; SLĂNINĂ, Valerina; BATYR, Ludmila; CHISELITA, Oleg; GUTSUL, Tatiana. Nanobioremediation: the effects of nanoscaled zerovalent iron on the activity of the soil microbial biomass and exogenous pop degrading microorganisms in soil polluted by pops. In: Microbial Biotechnology. Ediția 4, 11-12 octombrie 2018, Chișinău. Chișinău, Republica Moldova: Institutul de Microbiologie şi Biotehnologie, 2018, pp. 23-24. ISBN 978-9975-3178-8-7.
Ediția 4, 2018
Conferința "Microbial Biotechnology" |
Chișinău, Moldova, 11-12 octombrie 2018
Nanoscaled zero-valent iron (NZVI) is widely studied and used as means of environmental remediation, including in cases of soil pollution by persistent organic pollutants (POPs). NZVI is also recommended for nanobioremediation, i.e. for improving the microbial activity in the polluted soils, and, consequently, stimulating soil bioremediation processes. The purpose of this work was to estimate the impact of NZVI on the soil microbial biomass (SMB) and the activity of exogenous POP degrading microorganisms in a soil characterized by long-term pollution by POPs. The studied NZVI (1.5-2.5 nm) was stabilized by poly-N-vinylpyrrolidone. It was introduced into soil in the form of crystal powder mixed with talc. The polluted soil (sampled from a former pesticide deposit site) contained 2 mg/kg of DDTs and 30 mg/kg of trifluralin. The introduction of NZVI (100 mg/kg) into the polluted soil didn’t cause substantial increases of the SMB within the first 30 days of incubation (the subsamples of treated and untreated soil were kept in the dark, moistened at 40% of water holding capacity, aerated, and at the constant temperature of 25o C). The only statistically significant effect was observed by day 16 when the SMB (in the treated soil subsample) was 8.6% higher than in the control (with talc). The greatest effects of NZVI on the SMB (up till +27.3% as compared to the control) were observed in cases when the soil was additionally treated by two consortia of exogenous microorganisms (fig. 1) selected for their ability to actively grow in media containing NZVI and trifluralin (the latter as the only source of carbon). The SMB in the soil subsamples with the consortia but without NZVI was smaller than in the parallel cases with NZVI. It was also observed that within the first 4 days of the incubation NZVI was able to substantially (by 16-18 times) increase the number of CFU of at least one of the microbial strains introduces into the polluted soil with the consortia (fig. 2). Conclusions: (1) NZVI can have substantial positive effects on the SMB and exogenous microorganisms introduced into soil for bioremediation purposes; (2) the effects from a single NZVI treatment decrease with time, implying need for repeated treatments; (3) Within the studied conditions NZVI treatments did not cause any negative influence on the SMB and, thus, did not imply any environmental risk; (4) NZVI can be successfully used for nanobioremediation.