Heat loss and respiration following amendment with glucose were recorded for soils contaminated with heavy metals and organic pesticides over a period up to 28 days. For this purpose, measuring ampoules were adapted to enable measurement of heat loss and CO2 evolution on the same soil sample and at the same time. Heat loss and CO2 evolution were highly correlated (r(2) = 0.83), which is explained by the fact that in our studies heat loss from soils could be almost entirely attributed to metabolic reactions transforming glucose into CO2. These results demonstrate that the described adapted ampoules can be useful instruments to monitor microbial activity both accurately and economically by heat loss and CO2 production on the same soil samples during decomposition of various C substrates.