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The studies were carried out on material representing 13 different soil profiles from various regions of Poland. The content of total iron in 6 granulometric fractions of soils derived from various parent material showed high variation. The most varied with respect to the content of iron are the clay fractions, and the least are silt and sand fractions. The richest in total iron are fractions occurring in smallest amounts, and the poorest are those which dominate in granulometric composition.
The concentrations of total iron were determined in the 30 rainwater samples collected at Gdynia station, located in the coastal zone of Gulf of Gdansk. The samples were assembled from December 2002 to November 2003. Total iron concentrations were measured using a colorimetric method with bathophenanthroline. The concentrations of major rain components (Na⁺, NO₃⁻-, Cl⁻, SO₄²⁻) were also determined. Concentrations of Fetot ranged from 0.26 μg·dm⁻³ to 0.51·10⁻³ μg·dm⁻³. The total annual flux of Fetot was 11.22 mg·m⁻²yr⁻¹, which suggests that wet deposition can be one iron source for phytoplankton in the Southern Baltic. Iron in rain came from both terrestrial areas and seawater. Particularly at E&SE winds the swash zone saturated with marigenic aerosols was a significant source of iron. In these causes an anthropogenic influence on rain acidification was found to be minimal.
The concentration of total iron and iron (II ) extracted by hot twice distilled water was analyzed in following medicinal plants collected from natural areas: St Johns wort (Hypericum perforatum L.), yarrow (Achillea millefolium L.), nettle (Urtica dioica L.) and birch (Betula pendula Roth.). Total iron was determined by FAAS method after microwave mineralization of samples, whereas Fe (II ) was extracted by twice distilled water in temperature of 85ºC and determined spectrophotometrically with use of o-phenantroline. The obtained results indicate that total iron content is from several dozen to more than 200 μg/g of dry plant weight and is correlated with plant species. In case of iron (II ) it was determined in amounts ten times less than total concentration of the element. It was noticed that level of that form of iron is positively related to total amount of iron in analyzed medicinal plants. Extremely high concentration of both forms of iron was characteristic for one sample of nettle collected in the Vistula Sand Bar. Based on the conducted research it is possible to state that iron on +2 oxidation state extracted by water can become a source of bioavailable form of this element for human.
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