The aim of the current study was to screen and identify heavy metal (chromium, cadmium, and lead) associated bacteria from petroleum-contaminated soil of district Muzaffarabad, Azad Jammu and Kashmir, Pakistan to develop ecofriendly technology for contaminated soil remediation. The petroleum-contaminated soil was collected from 99 different localities of district Muzaffarabad and the detection of heavy metals via an atomic absorption spectrometer. The isolation and identification of heavy metals-associated bacteria were done via traditional and molecular methods. Resistogram and antibiogram analysis were also performed using agar well diffusion and agar disc diffusion methods. The isolated bacteria were classified into species, i.e., B. paramycoides, B. albus, B. thuringiensis, B. velezensis, B. anthracis, B. pacificus Burkholderia arboris, Burkholderia reimsis, Burkholderia aenigmatica, and Streptococcus agalactiae. All heavy metals-associated bacteria showed resistance against both high and low concentrations of chromium while sensitive towards high and low concentrations of lead in the range of 3.0 ± 0.0 mm to 13.0 ± 0.0 mm and maximum inhibition was recorded when cadmium was used. Results revealed that some bacteria showed sensitivity towards Sulphonamides, Norfloxacin, Erythromycin, and Tobramycin. It was concluded that chromium-resistant bacteria could be used as a favorable source for chromium remediation from contaminated areas and could be used as a potential microbial filter.

• Klíčová slova
• Bacillus spp, Antibiogram analysis, Heavy metals, Petroleum contaminated soil, Resistogram analysis, Ribotyping,
• MeSH
• antibakteriální látky * farmakologie   MeSH
• Bacteria * účinky léků   klasifikace   izolace a purifikace   genetika   MeSH
• chrom metabolismus   MeSH
• kadmium analýza   MeSH
• látky znečišťující půdu * analýza   MeSH
• mikrobiální testy citlivosti * MeSH
• olovo MeSH
• půda chemie   MeSH
• půdní mikrobiologie * MeSH
• ropa mikrobiologie   analýza   MeSH
• těžké kovy * farmakologie   analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Pákistán MeSH
• Názvy látek
• antibakteriální látky * MeSH
• chrom MeSH
• kadmium MeSH
• látky znečišťující půdu * MeSH
• olovo MeSH
• půda MeSH
• ropa MeSH
• těžké kovy * MeSH

Two long-term contaminated soils differing in contents of Pb, Zn, As, Cd were compared in a microcosm experiment for changes in microbial community structure and respiration after various treatments. We observed that the extent of long-term contamination (over 200 years) by toxic elements did not change the total numbers and diversity of bacteria but influenced their community composition. Namely, numbers of Actinobacteria determined by phylum specific qPCR increased and also the proportion of Actinobacteria and Chloroflexi increased in Illumina sequence libraries in the more contaminated soil. In the experiment, secondary disturbance by supplemented cadmium (doses from double to 100-fold the concentration in the original soil) and organic substrates (cellobiose or straw) increased bacterial diversity in the less contaminated soil and decreased it in the more contaminated soil. Respiration in the experiment was higher in the more contaminated soil in all treatments and correlated with bacterial numbers. Considering the most significant changes in bacterial community, it seemed that particularly Actinobacteria withstand contamination by toxic elements. The results proved higher resistance to secondary disturbance in terms of both, respiration and bacterial community structure in the less contaminated soil.

• Klíčová slova
• actinobacteria, cellobiose, diversity, respiration, straw,
• Publikační typ
• časopisecké články MeSH

On the basis of a previous study performed in our laboratory, the use of organic and inorganic amendments can significantly modify the Hg mobility in soil. We have compared the effectiveness of organic and inorganic amendments such as digestate and fly ash, respectively, reducing the Hg mobility in Chernozem and Luvisol soils differing in their physicochemical properties. Hence, the aim of this work was to compare the impact of digestate and fly ash application on the chemical and biochemical parameters in these two mercury-contaminated soils in a model batch experiment. Chernozem and Luvisol soils were artificially contaminated with Hg and then incubated under controlled conditions for 21 days. Digestate and fly ash were applied to both soils in a dose of 10 and 1.5 %, respectively, and soil samples were collected after 1, 7, 14, and 21 days of incubation. The presence of Hg in both soils negatively affected to processes such as nitrification, provoked a decline in the soil microbial biomass C (soil microbial biomass C (MBC)), and the microbial activities (arylsulfatase, and β-glucosaminidase) in both soils. Meanwhile, the digestate addition to Chernozem and Luvisol soils contaminated with Hg improved the soil chemical properties (pH, dissolved organic carbon (DOC), N (Ntot), inorganic-N forms (N-NH4 (+) and N-NO3 (-))), as consequence of high content in C and N contained in digestate. Likewise, the soil MBC and soil microbial activities (dehydrogenase, arylsulfatase, and β-glucosaminidase) were greatly enhanced by the digestate application in both soils. In contrast, fly ash application did not have a remarkable positive effect when compared to digestate in Chernozem and Luvisol soil contaminated with mercury. These results may indicate that the use of organic amendments such as digestate considerably improved the soil health in Chernozem and Luvisol compared with fly ash, alleviating the detrimental impact of Hg. Probably, the chemical properties present in digestate may determine its use as a suitable amendment for the assisted-natural attenuation of mercury-polluted soils.

• Klíčová slova
• Digestate, Fly ash, Mercury, Microbial activity, Microbial biomass, Nitrification, Soil pollution,
• MeSH
• arylsulfatasy chemie   MeSH
• bakteriální proteiny chemie   MeSH
• hexosaminidasy chemie   MeSH
• koncentrace vodíkových iontů MeSH
• látky znečišťující půdu analýza   chemie   MeSH
• oxidoreduktasy chemie   MeSH
• popel uhelný chemie   MeSH
• půda chemie   MeSH
• půdní mikrobiologie * MeSH
• regenerace a remediace životního prostředí MeSH
• rtuť analýza   chemie   MeSH
• znečištění životního prostředí MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• arylsulfatasy MeSH
• bakteriální proteiny MeSH
• hexosaminidasy MeSH
• látky znečišťující půdu MeSH
• oxidoreduktasy MeSH
• popel uhelný MeSH
• půda MeSH
• rtuť MeSH