THE USE OF MICROBIAL PARAMETERS IN MONITORING SOIL POLLUTION BY HEAVY-METALS

Microbial parameters appear very useful in monitoring soil pollution by heavy metals, but no single microbial parameter can be used universally. Microbial activities such as respiration, C and N mineralization, biological N2 fixation, and some soil enzymes can be measured, as can the total soil microbial biomass. Combining microbial activity and population measurements (e.g., biomass specific respiration) appears to provide more sensitive indications of soil pollution by heavy metals than either activity or population measurements alone. Parameters that have some form of ''internal control'', e.g., biomass as a percentage of soil organic matter, are also advantageous. By using such approaches it might be possible to determine whether the natural ecosystem is being altered by pollutants without recource to expensive and long-running field experiments. However, more data are needed before this will be possible. Finally, new applications of molecular biology to soil pollution studies (e.g., genetic fingerprinting) which may also have value in the future are considered.