To Örebro University

During the last decades, Potentially Toxic Elements (PTEs) have steadily y become a serious environmental problem due to their insusceptibility in the environment. Special attention is drawn to brownfields that are chosen for reuse, e.g., as residential area, since safety for persons has to be ensured. Vegetation is a valuable indicator of environmental contamination by PTEs in general as they are exposed to these substances via soil and subsequent root uptake as well as via wet and dry precipitation on the outer surface with uptake through stomata.

The study area of the present investigation was Norra Hamnstaden in Lidköping (Sweden) having an over 100 years’ lasting history of industrial activity. S ince 1912 porcelain has been produced at this place and the resultant industrial waste was deposited close by. Thus, elevated levels of metals used for porcelain glazes, especially Pb, have been found in this area. Due to plans to reuse this zone as residential area, thoroughly risk assessment studies are needed. In order to estimate the bioavailability of certain PTEs, their uptake by plants was investigated through their quantification in birch leaves (Betula pendula) as wel las in differently aged pine needles (Pinus sylvestris) of trees grown in the area of interest. Sampling was carried on five trees, each once per month in the period from May to August 2018. Different uptake patterns were observed for birch leaves and pine needles, for the latter even varying with age. Especially the birch samples showed higher Pb contents compared to the reference trees, but elevated levels were also found for other metals, e.g,. Co, Mo, and Ni. Also, the pine needles have higher Pb levels, however the ratio to the reference tree is lower than for the birch leaves.

The soil metal contents at a depth of 0.5 to 1 m determined in a previous study were used as basis for the calculation of Accumulation Factors (AF = content in leave/content in soil) in birch leaves. Factors above one were obtained for Ba, Cd, and Zn, whilst Pb was the metal least taken up, the AF being 0.007.