The assessment of the total mercury content in soil profiles of Pomerania and Kujawy region under the different land use

Celem pracy była ocena całkowitej zawartości rtęci w profilach gleb uprawnych oraz leśnych Pomorza i Kujaw. Oznaczono podstawowe właściwości gleb oraz zawartość rtęci metodą atomowej spektrometrii absorpcyjnej (analizator AMA-254). Określono wartość tła geochemicznego, będącą średnią zawartością Hg w skale macierzystej gleb różnie użytkowanych. Ze względu na odmienną litogenezę oraz skład granulometryczny gleb wykorzystano - do obliczeń wskaźnika zanieczyszczenia - średnią zawartość Hg wynoszącą 17,6 ±8,5 μg.kg-1 dla gleb uprawnych oraz 3,1 ±1,8 μg.kg-1 dla gleb leśnych. Stwierdzono istotnie dodatnią korelację między koncentracją rtęci a zawartością Corg. Zawartość Hg była istotnie dodatnio skorelowana z ilością frakcji iłowej w glebach uprawnych oraz madach czarnoziemnych typowych. Średnia wartość wskaźnika zanieczyszczenia wskazuje na znaczące nagromadzenie Hg w poziomach próchnicznym gleb leśnych oraz orno-próchnicznym gleb uprawnych. Całkowita koncentracja rtęci w glebach badanego regionu kształtowała się na poziomie zawartości naturalnej i wynosiła w poziomach organicznych od 216,9 do 549,3 μg-kg-1 oraz od 0,9 do 305,6 μg-kg-1 w poziomach mineralnych.Determination of natural mercury content in soils is difficult to estimate due to the presence of anthropogenic contaminants. Moreover, concentration, its form and transformations depends on many factors such as the quantity and quality of soil colloids, surface area, pH, sorption capacity, redox conditions or microbial activity. The aim of the study was to characterize the total content of mercury in soils of arable and forest areas of the Pomerania and Kujawy region depending on the land use. Research material were taken from 13 profiles of Luvisols, 5 profiles of Phaeozems, 3 profiles of Cambisols, 4 profiles of Fluvisols. Forest soils were represented by 18 soil profiles of Arenosols and 1 profile of Cambisol. The influence of selected soil properties on content and distribution of mercury in soil profiles were also determined. The validation of the procedure was confirmed with reference materials TILL-3 and SO-4. Research was also based on the contamination factor (CF). The statistical analyses were calculated using Statistica 10.0 computer program. The total content of mercury in the analyzed soils ranged 0.9-305.6 μg-kg-1, and was at the natural level. According to Polish Minister of the Environment Regulation (September 9, 2002), concerning soil quality standards and earth quality standards the analyzed soils were classified as not contaminated with mercury. As the value of the geochemical background for analyzed soils, the mean total Hg content in parent material of soils was used, and because of different lithogenesis was 17.6 ±8.5 μg.kg-1 for arable soils and 3.1 ±1.8 μg.kg-1 for forest soils. The average value of contamination factor indicates significant anthropogenic Hg accumulation in the humus horizon of forest soils and in the topsoil of arable soils, especially in Fluvisols. The values of distribution indicator also revealed higher levels of the accumulation of mercury in topsoil of Fluvisols, which is effect of the origin of these soils (deposition of fluvial sediments enriched in Hg on the floodplain area). A significant influence of organic matter on the immobilization of mercury was noticed in surface horizons of forestry soils, confirmed by the value of correlation coefficients. Also weak significant correlation coefficient between Hg content and the amount of clay fraction in arable soils was determined, and moderate in alluvial soils