The amounts of heavy metals in some lichens of the Negev Desert

Abstract

The amounts of Mn, Cr, Pb, Zn, Cu and Ni in the lichens Squamarina crassa, Teloschistes lacunosus, Ramalina maciformis, Diploschistes steppicus and Caloplaca ehrenbergii growing in the Negev Desert, Israel, were measured. The amount of Pb in S. crassa growing close to a main motorway was relatively high and much higher than in the soil—the substrate of S. crassa. The high coefficients of variation for Mn and Cu found in several lichens are attributed to large particles entrapped in the lichen thallus. It is suggested that the low coefficients of variation found for Zn in all the lichens studied indicate that this element occurs in small, well-dispersed particles. Measuring the heavy metal content of desert lichens is important because of their biomonitoring potential and also because snails and goats feed on them.