Aspects of the biomonitoring studies using mosses and lichens as indicators of metal pollution.

It has been shown that mosses and lichens, in spite of all disadvantages, are good tools for air pollution monitoring, but best results could be achieved while using both of them together, because of differences in their metal uptake and retention. The researcher dealing with biomonitoring faces many difficulties; for example, in the use of lichens, those of similar composition are not easy to find, because of the differences caused by the tree on which the lichens are growing. Also, terrestrial moss is not always a good choice because of variations in its composition caused by the area it is growing on. The "bag" technique seems to be suitable in many cases because it gives the possibility of comparing wet and dry deposition and there are no differences in its content at the beginning of research. The bag construction should be made to keep the humidity of the sample stable to avoid its drying. For a complete and informative data set the biomonitor content should be compared with precipitation, particulate matter fractionation, and speciation data and also with medical statistics to evaluate the correlation between the amount of pollutants in the atmosphere and the human reaction to them.