Heavy metal pollution by atmospheric transport in natural soils from the northern part of Eastern Carpathians

The present paper is a study of the heavy metal contamination of natural so ils due to atmospheric transport in the northern part of Eastern Carpathian s. The study area is located north of Baia Mare, the main Romanian centre f or processing complex sulphide ores. Ten undisturbed soil profiles of andos ols and andic soils were investigated. The distribution of heavy metals (Pb , Cu, Zn, Mn, Ni, Co, Cr and Cd) was studied along the soil profile and at specific distances from the pollution sources. In addition to the total nit ric acid soluble fraction of the metals, amounts of lead, copper, zinc and manganese extractable with 0.05 M hydrochloric acid were determined to eval uate the fraction of each metal potentially available to plants. Surface so ils in the Ignis Mountains (10 km from Baia Mare) were more polluted with l ead (200-800 ppm), with the concentration decreasing with distance from the processing plants. Lower lead concentrations were observed in the deeper s oil horizons. The fraction of lead extractable in 0.05 M hydrochloric acid was generally higher at high total concentrations of lead. From its geograp hical and soil profile distributions it is also evident that cadmium was al so supplied in appreciable amounts to the topsoil from the same polution so urces, whereas the trend was weaker for zinc and chromium and not evident f or copper, manganese, nickel, or cobalt. The fraction extractable with 0.05 M hydrochloric acid generally followed the order Pb > Cu > Zn > Mn.