We investigated the soils of the remediated children’s playground in the kindergarten Hiša pri ladji in the municipality of Ljubljana. The remediation was carried out in 2015 by replacing of a 50 cm topsoil layer due to the increased lead (Pb) content. Pb content ranged from 24,8 to 2793 mg/kg in topsoil 0-10 cm, and from 32,4 to 6616 mg/kg in soil layer 10-20 cm. After removing the contaminated soils, a layer of gravel was inserted and then covered with new soils with Pb content 51,4 mg/kg, cadmium content 0,41 mg/kg, arsenic content 9,3 mg/kg and zinc content 140 mg/kg. The aim of this thesis was to check whether the concentrations of Pb and other analysed heavy metals increased after five and a half years and represent the health risk to the children. In the year 2021 Pb content ranged from 39,3 to 60,6 mg/kg in the sampling depth 0-10 cm, and from 40,9 to 51,5 mg/kg in the sampling depth 10-20 cm. Samples from the depth 30-40 cm represents the carbonate gravel, which was inserted in 2015 and has a task to prevent recontamination of upper layers from lower layers of contaminated soils. Pb content from the sampling depth 60-70 cm confirmed that soils are still contaminated. Pb analyses were performed by the non-destructive method of X-ray fluorescence spectrometry (XRF) and also with aqua regia extraction method. Pb bioavailability was determined by the in vitro bioaccessibility assay developed by U.S. EPA. Absolute bioavailability of Pb ranged from 27,6 to 33,8 %. Using IEUBK model, we calculated the expected Pb concentration in the blood of children, which was below 10 µg/dl. We carried out also soil properties like carbonate content, soil acidity, soil organic matter and available phosphorus and potassium for topsoil management recommendations.
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