3.3 Soil Standards

Polluted waters and air will in many cases unload the pollutant onto the soil . The land is also affected through anthropogenic activities. If the land is not polluted through emissions from industrial processes, which are eventually precipitated onto the land, then the later may be polluted through activities such as mining, agriculture, solid waste and liquid waste disposal.

A variety of chemicals, both organic and inorganic compounds, contaminate the soil in varying degrees. Mining and smelting processes and fuel combustion have given rise to contaminated soils containing a variety of heavy metals. Oil and tar residues from gas and oil refineries can contaminate the soils. Land-fill sites save increased methane concentrations in the air environment.

Direct application of fertilisers, pesticides and contaminated sewage sludges or irrigation water have contaminated many soils by altering the microbial activities and emission of green-house gases like nitrogen dioxide, nitrous oxide, among other, into the atmosphere.

Tanzania has had standardised test methods for soil for quite some time, developed by the Mlingano Research Centre -Soil Central Laboratory (Tanga), one of the oldest research centres in the country. The methods used by the Soil Central Laboratory were aimed at adapting internationally accepted procedures. The standards being proposed form only a part of the said procedures and are being adopted from the International Organisation for
Standardisation. For the time being, the standards being proposed are test methods.