Relationships between Bacterial Tolerance Levels and Forms of Copper and Zinc in Soils

• Published in: Journal of environmental quality 2002-09, Vol.31 (5), p.1570-1575
• Main Authors: Saeki, K, Kunito, T, Oyaizu, H, Matsumoto, S
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Animal, plant and microbial ecology; Applied ecology; Bacteria; Biological and medical sciences; Calcium chloride; Copper; Copper - adverse effects; Copper - pharmacology; Correlation coefficient; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; Heavy metals; Metal concentrations; Metal ions; Microbial ecology; Saturated soils; Soil; Soil Microbiology; Soil Pollutants - adverse effects; Soil Pollutants - pharmacology; Soil solution; Solubility; Speciation; Terrestrial environment, soil, air; Zinc; Zinc - adverse effects; Zinc - pharmacology
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2002.1570

The effects of various fractions of copper (Cu) and zinc (Zn) on soil bacteria were evaluated by the heavy metal tolerance level of the bacterial community (IC50) in soil samples collected near a mine. The IC50 values had no relationship with the total concentrations of Zn and Cu in the soils, but were weakly correlated with the 0.05 M CaCl2–extractable form of each metal in the soils (Cu: R 2 = 0.670, p < 0.01; Zn: R 2 = 0.453, p < 0.05). It was found that the IC50 correlated strongly with the total concentration of each metal in the extracts from water-saturated soil samples, described below as “soil solution” (Cu: R 2 = 0.789, p < 0.01; Zn: R 2 = 0.617, p < 0.01). The speciation of these metals in the soil solutions was estimated using an equilibrium thermodynamic computer model, SOILCHEM. Simulated free Cu ion ranged from 18 to 98% of total Cu, and organic complexes of Cu ranged from