Most studies dealing with metals in soil systems concern total metal concentration. However, availability of metals to organisms is not dependent on the total amount of a metal, which is present in the soil, but rather on how it is chemically bound within the soil. In the summer of 1999, 98 samples of topsoil were collected near traffic arteries and at playgrounds, at schools and at several single playgrounds in the centre of Oslo, Norway. At 24 playgrounds in the central districts, additional samples of sand from sandboxes were taken near playing facilities made of impregnated or painted wood. Besides the determination of the acid-soluble concentrations of seven trace metals, a sequential five- stage extraction was accomplished for all 122 samples. These five fractions (i.e. exchangeable, carbonate, reducible substrate, organic and residual) were analysed for As. At the 24 playgrounds, the acid- soluble concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn in topsoil samples are higher than in samples of sand collected from the sandboxes. The differences in As concentrations between topsoil and sandbox samples are small. In all the topsoil samples, the concentrations of As exceed the norm value for polluted soil used by the Norwegian authorities. In the sandbox samples, 63% of the samples exceed this value. In the exchangeable, the carbonate and the reducible substrate fractions, As concentrations in the sandbox samples lie at a higher level than concentrations in topsoil samples taken at the same playground. Leaching of As compounds from impregnated and painted wood has probably caused elevated concentrations of this element. In the organic fractions, only one playground has a higher concentration in the sandbox sample than in the topsoil sample. In the residual fraction, only four playgrounds have As concentrations that are higher in the sandbox sample than the concentration in the topsoil. Despite the fact that concentrations in sand are lower than in topsoil, 15 of 24 sandbox samples contain more As than the norm value for polluted soil.
Article Subject Terms: Arsenic; Cadmium; Leaching; Lead; Metals; Recreation areas; Sand; Soil; Soil contamination; Wood; schools; summer; trace metals; traffic; Article Geographic Terms: Norway; Norway, Oslo; p 5000 land pollution