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[An ecologic hygiene assessment of the microbiological processes in soil contaminated with sulfonol and lead].

Alteration of the microbial coenosis and biological activity of different types of soils as well as peculiarities of survival of sanitary-significant and pathogenic microorganisms under the effect of sulphonol and a sulphonol-lead complex have been studied in the laboratory model experiment. The most sensitive tests were as follows: the number of nitrifying bacteria; nitrifying, proteolytic, dehydrogenase and cellulase activity; survival of salmonella and lactose-positive colibacilli. Under the effect of the tested sulphonol (0.5 and 3 mg/l) and lead (0.1 and 2 mg/l) concentrations the self-purification processes in soil were not substantially disturbed, though surfactants negatively affected viability of enterobacteria.

Benzenesulfonates↗
PubMed2006

Aerobic and anaerobic biodegradation of phenol derivatives in various paddy soils.

Microbiological degradation of phenol and some of its alkyl-derivatives (p-cresol, 4-n-propylphenol, 4-i-propylphenol, 4-n-butylphenol, 4-sec-butylphenol, 4-t-butylphenol, and 4-t-octylphenol) was examined under both aerobic and anaerobic conditions in seven Japanese paddy soils. Aerobic biodegradation of phenol derivatives was detected in all the paddy soils examined. The half-lives ranged from 2 to 19 days. The aerobic degradation rate of 4-t-octylphenol was correlated inversely with the total carbon contents of paddy soils, and there were significant inverse correlations between the aerobic degradation rate and the size of alkyl groups of alkylphenols. Anaerobic biodegradation of phenol and p-cresol was detected in three soils with the half-lives ranging from 24 to 260 days for phenol and from 11 to 740 days for p-cresol, respectively. The three soils were characterized by low contents of nitrate and iron oxides. Other soil properties did not show any significant correlations with the anaerobic degradation rates. In one soil, we found for the first time anaerobic biodegradation of 4-n-propylphenol. However, the other five compounds (4-i-propylphenol, 4-n-butylphenol, 4-sec-butylphenol, 4-t-butylphenol and 4-t-octylphenol) were not degraded over 224 days of incubation. These results suggest that phenol and all the alkylphenols were degraded within several days when paddy soil is not flooded and so under aerobic conditions. Under flooded and anaerobic conditions, 4-n-propylphenol would be degraded as well as phenol and p-cresol while alkylphenols with long and branched alkyl chains were hardly degraded at all.

Agriculture↗
PubMed2003

Novel approach to monitoring of the soil biological quality.

In this study, a new approach to interpretation of results of the simple microbial biomass and respiration measurements in the soil microbiology is proposed. The principle is based on eight basal and derived microbial parameters, which are standardized and then plotted into sunray plots. The output is visual presentation of one plot for each soil, which makes possible the relative comparison and evaluation of soils in the monitored set. Problems of soil microbiology, such as the lack of benchmarking and reference values, can be avoided by using the proposed method. We found that eight parameters provide enough information for evaluation of the status of the soil microorganisms and, thus, for evaluation of the soil biological quality. The usage of rare parameters (potential respiration PR, ratio of potential and basal respiration PR/BR, biomass-specific potential respiration PR/C(bio), available organic carbon C(ext), and biomass-specific available organic carbon C(ext)/C(bio)) can be recommended, besides classical and well-known parameters (microbial biomass C(bio), basal respiration BR, metabolic coefficient qCO(2)). The combination of basal parameters and derived coefficients can also extend our knowledge about the condition of the soil microorganisms. In monitoring the case studies presented, we observed that soils evaluated to possess good biological quality displayed generally higher values of organic carbon, total nitrogen, clay, and cation exchange capacity. The soils of good biological quality can display higher levels of contaminants. This is probably related with the higher content of organic carbon and clay in these soils.

Aluminum Silicates↗
PubMed2006

Effects of long-term heavy metal contamination on soil microbial characteristics.

In this study, total heavy metal content and its effects on soil microbiological characteristics were investigated in soil samples from an area with known long-term pollution problems. The total heavy metal concentrations of contaminated soil samples were 109 and 1,558 mg/kg for Hg and As, respectively. Key microbiological parameters measured included dehydrogenase activity, ATP content and number of culturable aerobic bacteria, actinomycetes, fungi and asymbiotic nitrogen-fixers. Quantitative analysis of soil microbial populations shows a marked decrease in total culturable numbers of the different microbial groups of the contaminated soil samples. Certain groups of soil microbes were particularly sensitive to long-term contamination (asymbiotic nitrogen-fixers and heterotrophic bacteria). Dehydrogenase activity was found to be a sensitive assay for determining the effect of heavy metals on physiologically active soil microbial biomass and sustains the high applicability of this parameter for soil ecotoxicological testing as reported by other authors.

Actinobacteria↗