Naslov
Distribution and fractionation of heavy metals in agricultural soils

Autori
Romić, Marija ; Romić, Davor ; Bašić, Ferdo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
1st International Symposium on Environmental Management, Book of Abstracts, October 1-3, 2003 ; zagreb Fair, Croatia / Koprivanac, Natalija - Zagreb, 2003

Skup
1st International Symposium on Environmental Management, October 1-3, 2003 ; zagreb Fair, Croatia

Mjesto i datum
Zagreb, Hrvatska, 01.10.2003. - 03.10.2003

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
bioavailable form; geochemical phases; soil profile; translocation of metals

Sažetak
Soils in urban and industrial areas are exposed to a large number of potential sources of contamination by heavy metals, which include deposition of various waste materials, release of harmful gases into the atmosphere and input of agrochemicals into soil. These same elements can be found in the parent material from which the soils developed. Whether the said inputs will become toxic and to what degree mobile depends on a number of factors: soil type, land use, geomorphological characteristics within the soil type and/or exposure to emission sources. As they are potentially toxic to plants and animals, their real status has to be assessed. Determination of the total content of heavy metals in soil is the main indicator for assessment of the extent of its contamination ; however, long-term risk estimates and direct contamination effects are based on their bioavailability and/or mobility. For this reason, investigations were undertaken on 100 ha of agricultural soilsin the Zagreb region, developed on alluvial Holocene sediments, on which vegetables and field crops (predominantly maize) are produced. The test plot was located in the immediate vicinity of ecologically risky facilities: the city waste dump, a very busy ring road, the district-heating plant and the main airport. Drinking water is intensively pumped from the Quaternary fluvial deposits in a wider area, so part of the surrounding area is treated as a water protection zone. The research goal was to determine the accumulation of heavy metals in the topsoil and their distribution within the geochemical phases vertically along the soil profile. Topsoil samples were taken according to a regular grid of 250 x 250 m. Two pedological profiles were opened as well, while samples for chemical analyses were taken from genetic horizons to a 2 m depth. Soil texture, pH, total organic matter and total contents of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in topsoil samples using flame AAS after extraction in aqua regia, while in soil samples taken from genetic horizons also CaCO3 content, effective cation exchange capacity and exchangeable cations were analyzed, and selective sequential analysis was done. Five fractions in the soil profile genetic horizons were separated by sequential analysis: exchangeable, carbonate, reductive, organic and residual. Comparison with the background concentrations of the wider area pointed to raised concentrations of lead, zinc and nickel in the surface layer of agricultural soils, but their average values are below the norm values according to Croatian government regulations. In surface horizons of the studied profiles, only nickel concentrations exceed the maximum allowable value. For heavy metals to be translocated by water through the soil profile, they have either to be in the soluble phase or bound to mobile particles. Metals can form complexes with particles of organic matter in topsoil and as such can be translocated vertically along the profile depth. It is generally taken that the water-soluble and exchangeable fractions, and sometimes also the organic fraction, are bioavailable forms. Results of selective sequential analyses in two Molic Fluvisol profiles on the studied location provided no evidence of translocation of metals through the soil profile, and thereby no hazard of their leaching into groundwater.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

POVEZANOST RADA