Soil microbial biomass and organic matter dynamics in metal-contaminated soils

Barajas-Aceves, Martha (1994) Soil microbial biomass and organic matter dynamics in metal-contaminated soils. PhD thesis, University of Nottingham.

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A main aim of this thesis was to compare and evaluate different microbiological methods (total biomass or microbial activity) to detect effects of heavy metals on the functioning of the soil ecosystem. The biomass methods, which included biomass C, biomass ninhydrin-N, biomass N, ATP, substrate induced respiration and the activity methods, which included CO, evolution and arginine ammonification reliably detected effects of heavy metals on the soil microbial ecosystem in metal-contaminated soils from the Woburn Market Garden Experiment which contained, due to past sludge applications, Zn, Cu or Ni at around current European Union (EU) upper limits and Cd at around three times the limit. Most microbiological indices were decreased by up to about 50% in the most metal- contaminated soils and the results were comparatively simple to interpret.

Many more problems were encountered when soils from a non-experimental site in Spain, polluted by heavy metals from past mining activity, and now containing heavy metals at up to 27 times current EU limits were examined. Huge variability, caused, for example, by site variations in soil organic C, soil texture, agricultural management and topography, were encountered. While the biomass methods and most measurements of microbial activity (except COj-C evolved) gave some indication of a negative response to increases soil metal concentrations, linked parameters e.g. biomass specific respiration or biomass as a percentage of soil organic C provided much more sensitive indicators of the effects of metals on the soil ecosystem. It was concluded that extrapolation from the field experiment to the natural environment, while difficult, is now a practical proposition.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Young, S.D.
Marshall, S.J.
Keywords: Soils, Heavy metal content; Soil microbiology; Soil pollution; Biomass
Subjects: Q Science > QR Microbiology > QR100 Microbial ecology
Faculties/Schools: UK Campuses > Faculty of Science > School of Biosciences
Item ID: 67208
Depositing User: Airey, Ms Valerie
Date Deposited: 26 Nov 2021 09:14
Last Modified: 26 Nov 2021 09:19

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