Water serves as the transport medium through which nutrients and organic constituents pass into the microbial cell and metabolic waste products pass out of the cell. Nutrients required for cell growth are nitrogen, phosphorous, potassium, sulfur, magnesium, calcium, manganese, iron, zinc, copper, and trace elements. If nutrients are not available in sufficient amounts, microbial activity will become limited. Nitrogen and phosphorous are the nutrients most likely to be deficient in the contaminated environment. Phosphates can cause soil plugging as a result of their reaction with minerals, such as iron and calcium, to form stable precipitates that fill the pores in the soil and aquifer.
Temperature affects microbial activity in the environment.
The microorganisms remain viable at temperatures below freezing and will resume activity when the temperature rises. Heating the bioremediation site, such as by use of warm air injection, may speed up the remediation process. Too high a temperature can be detrimental to some microorganisms, essentially sterilizing the soil. Temperature also affects nonbiological losses of contaminants mainly through the increased volatilization of contaminants at high temperatures. Additionally, oxygen solubility decreases with increasing temperature.