1.1.1. Soil pollution
A coordinated system for inventory of soil pollution has been established in Bulgaria, which works on the basis of approved standards and a system for assessment of the degree of pollution. It includes a range of heavy metals, arsenic, radionuclides, persistent organic pollutants (POPs), pesticides and petroleum products. According to monitoring data (Todorova, 2003), the area of soils in Bulgaria contaminated with various chemicals and radionuclides is estimated as follows:
– Lands contaminated with heavy metals and arsenic 43 600 ha;
– Lands contaminated with radionuclides 1 049 ha;
– Lands contaminated with petroleum products and pesticides 137 ha;
– Other (including POPs) approx 100 ha;
Total 44 896 ha.
Soils contaminated with heavy metals and arsenic are more or less well studied and mapped. The pollution is the result of point sources and the contaminated sites are located in the vicinity of ferrous and non-ferrous metallurgical enterprises, along highways or near chemical enterprises. In most cases, contaminated soils contain a mixture of heavy metals. Among the most common pollutants are lead, copper, zinc, cadmium. Some soils are contaminated with arsenic.
Bulgarian soils are also polluted by the introduction of a number of chemicals to control diseases, pests and weeds in cultivated plants (fungicides, insecticides and herbicides) commonly called pesticides. These preparations decompose after a while and become harmless. Used in large quantities, they can accumulate in soil and plants and adversely affect animal and human health.