An attempt to determine the tissue contamination of Quercus robur L. and Pinus silvestris L. Foliage by particulates from zinc and lead smelters

Quantitative analyses of plant material from the surroundings of zinc and lead smelters demonstrate a distinct increase in the concentration of both elements. Concerning Pb, a similar phenomenon is known from around highways. The extent to which particulates from zinc and lead smelters are serious contaminants of Quercus robur and Pinus silvestris foliage was investigated. Chloroform and ultrasonic vibration was used to remove wax and particulates from the foliage surface. The X-ray fluorescence method was chosen to determine Fe, Zn, Pb, Se and Sr and the foliage surface was examined using a scanning electron microscope. The removal of wax and particulates led to a distinct decrease in all elements, sometimes to levels below those found in control samples. Although tissue contamination by particulates through stomata not protected by a wax layer (e.g. in Quercus robur) is possible, this seems to be of little importance. Fine wax crystals which cover the stomata (e.g. in Pinus silvestris) protect the tissue from contamination. This conclusion is perhaps valid for other plant species with similar types of stomata.