Certified reference material of lichen (CRM 482) for the quality control of trace element biomonitoring

Lichens are currently used as bioindicators to monitor air pollution and to follow changes in pollution patterns. In order to perform reliable biomonitoring, these analyses should give accurate results, which implies that a good quality control system should be applied. One way to achieve accuracy is to use certified reference materials (CRMs). In order to produce a lichen CRM, the BCR-programme (now renamed Standards, Measurements and Testing programme) of the European Commission has conducted a certification campaign involving expert laboratories. A lichen material has been collected on pine trees, oven-dried, homogenised and bottled, and its homogeneity and long-term stability verified. The material (CRM 482) was analysed by a group of 11 selected laboratories using different analytical methods. This paper describes the certification work performed to certify the elements Al, As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. Indicative values are given for Ba, Br, Ca, Co, Fe, K, Mn, Mo, P, S, Sb, Se, Sn and V.