engleski

Characterisation of soils samples from the roatian national park Velebit

Introduction Due to anthropological activities during the last decades, metal pollution has steadily become a serious environmental problem as a result of their toxicity. Heavy metals are accumulated in soils, crops or plants and can thus affect human physiological functions. Thus the soil characteristics responsible in metal accumulation and their bioavailability are of importance. These parameters are pH-value, CEC (cation exchange capacity), humidity, colour, and mineral composition. In the present study in soil samples from a remote area, like the National Park Northern Velebit are of interest to see the potential impact on plants, such as medical and aromatic herbs or conifers, grown there. The investigated soil has the following mineral composition: quartz, illite, chlorite, chloritesmectite and plagioclase. Vegetation in general is a useful indicator of environmental metal contamination via root uptake as well as via precipitation on the outer surface. Thus plants, like conifers, can be used to monitor pollution across both spatial and temporal scales. Methods All samples were collected in autumn 2012 in the National Park Northern Velebit. The soil samples were dried for 24 hours at 105°C. The pH-value of a suspension of the soil in distilled water and CaCl2 solution is measured using a glass-electrode. CEC is determined by spectrophotometry using the copper ethylenediamine complex. The plant parts were dried at ambient temperature. Total metal contents of Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sr, and Zn in the needles and shoots of a fir tree (Abies alba) were determined by inductively coupled plasma – optical emission spectrometry (ICP-OES) after acidic microwave assisted digestion. Results and Discussion The soil pH measured in water suspension is between 4.78 and 7.59, and 4.14 and 7.09 in CaCl2 solution. The CEC values range from 10.31 to 28.26 mEq/100g. In the fir tree Co is below LOD, Cd, Cr, and Pb are below 2 mg/kg, whereby Cr and Pb are present in higher concentrations in the needles. Contents up to 15 mg/kg were found for B, Ba, Cu, Mo, Ni, and Sr. Al, Fe and Zn were quantified with values of up to 100 mg/kg. Mn and Na were determined to be in range of 100 to 200 mg/kg. For the major elements contents of approx. 400-500 mg/kg were found for K, of about 1 g/kg for Mg, and the highest results for Ca ranging from 4 to 7 g/kg. Innovative aspects • Soil characterisation and plant elemental composition are the basis for risk assessment and estimation of environmental pollution.

soils; ICP-OES; CEC values

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