The aim of this study was to measure and compare methane oxidation rates of arable and grassland soils that received
7.5 t ha−1 y−1 of noncontaminated aerobically treated sewage sludge for ten years. Arable soils showed generally
lower methane oxidation rates (from 6 to 15∗10−3 h−1) than grassland soils (from 26 to 33∗103 h−1).
Oxidation rate constants (k) of soils amended with sewage sludge were remarkably close to their respective
untreated controls, but a soil, that had received a tenfold sewage sludge application (i.e. 75 t ha−1 y−1), showed
a statistically significantly higher k-value. Laboratory addition of up to 1000 mg Pb g−1 soil to this soil did not
cause any significant change in methane oxidation, but caused a decrease from 13.9 to 10.9×10−3 h−1 in the control
soil. Addition of Zn was muchmore toxic than Pb, with a significant decrease at 300 μg g−1 soil rate and an almost
complete inhibition at 1500 μg g−1 soil rate. Higher resistance was evident of sewage sludge treated soil in
comparison to control soil, for both biomass C and CH4 oxidation activity.
