The participation of toxic deposits in the brown coal overlay, which is exploited in the Turek region, is very small. These are Miocene deposits, mainly sands and loam and silt which contain pyrite (FeS2). They occur in the coal roof and in the coal free lenses and as a general rule they are deposited in the lower parts of the dumping ground. Their presence in the upper layer of the dumping ground indicates mining technological error. The weathering product of pyrite is sulphuric acid, iron compounds and sulphur. Forming sulphuric acid acidifies the ground and the reaction lowers pH in the range from 2.48-3.07. The very acid reaction is accompanied by high, toxic for plants, exchangeable acidity. The content of general sulphur in the upper 25 cm ground layer amounts from 800 to 1240 mg·kg-1 ground. The ratio of general sulphur to sulphate comes to 52.41.
Full text available in Polish in Adobe Acrobat format:http://www.npt.up-poznan.net/tom5/zeszyt6/art_106.pdf
Gilewska M., Otremba K., 2011. Geochemiczne właściwości gruntu pogórniczego zbudowanego z utworów mioceńskich. Nauka Przyr. Technol. 5, 6, #106.
Mirosława Gilewska
Zakład Rekultywacji z siedzibą w Koninie
Katedra Gleboznawstwa i Rekultywacji
Uniwersytet Przyrodniczy w Poznaniu
ul. Przemysłowa 120
62-510 Konin
Poland
e-mail: katrekult@wp.pl