The effect of pollutants (heavy metals and diesel fuel) on the respiratory activity of constructozems (artificial soils)

Young (1 month old) and mature (2 years old) constructozems (artificial soils) were supplemented with individual heavy metal salts or diesel fuel at different concentrations. The polluted and control constructozem variants were incubated and sampled at different time points to determine microbial biomass carbon (C_mic) and microbial respiration (MR). These parameters were found to be almost twice higher in the young than in the mature constructozem, with all pollutants causing an increase in C_mic, MR, and MR/C_mic = qCO₂ values. The pollutant type had an effect on MR and qCO₂ variances, and the time of exposure, on C_mic. The qCO₂ value showed a strong positive correlation with pollutant concentrations, allowing this parameter to be regarded as a suitable indicator of urban environmental pollution.