Concentration effects of 1,2-dichlorobenzene on soil microbiology

• Published in: Environmental toxicology and chemistry Vol. 18; no. 9; pp. 1891 - 1898
• Main Authors: Thompson, I.P, Bailey, M.J, Boyd, E.M, Maguire, N, Meharg, A, Ellis, R.J
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Periodicals, Inc 01.09.1999; SETAC
• Subjects: Animal, plant and microbial ecology; Applied ecology; biological activity in soil; Biological and medical sciences; Concentration effects; Dichlorobenzene; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; Microbial diversity; soil fumigants; Soil microbial biomass; Terrestrial environment, soil, air; Species diversity; Pollutant; Microbiology; Microcosm; Bacteria; Environmental factor; Biological indicator; Soil pollution; Microbial biomass; Microbial community; Concentration distribution
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1002/etc.5620180904

The effect of increasing concentrations (65, 130, 325, 1,300, and 3,250 micrograms/g soil dry weight) of 1,2-dichlorobenzene(1,2-DCB) on the microbial biomass, metabolic potential, and diversity of culturable bacteria was investigated using soil microcosms. All doses caused a significant (p < 0.05) decrease in viable hyphal fungal length. Bacteria were more tolerant, only direct total counts in soils exposed to 3,250 micrograms/g were significantly (p < 0.05) lower than untreated controls, and estimates of culturable bacteria showed no response. Pseudomonads counts were stimulated by 1,2-DCB concentrations of up to 325 micrograms/g; above this level counts were similar to controls. Fatty acid methyl ester analysis of taxonomic bacterial composition reflected the differential response of specific genera to increasing 1,2-DCB concentrations, especially the tolerance of Bacillus to the highest concentrations. The shifts in community composition were reflected in estimates of metabolic potential assessed by carbon assimilation (Biolog) ability. Significantly fewer (p < 0.05) carbon sources were utilized by communities exposed to 1,2-DCB concentrations greater than 130 micrograms/g (< 64 carbon sources utilized) than control soils (83); the ability to assimilate individual carbohydrates sources was especially compromised. The results of this study demonstrate that community diversity and metabolic potential can be used as effective bioindicators of pollution stress and concentration effects.