Two lichens differing in element concentrations have similar spatial patterns of element concentrations responding to...

Area of Science:

• Environmental Science
• Biomonitoring
• Geochemistry

Background:

• Epiphytic lichens are sensitive bioindicators of environmental pollution.
• Road traffic is a significant source of atmospheric elemental deposition.

Purpose of the Study:

• To assess the contribution of soil input and road traffic to elemental burdens in lichens.
• To compare elemental concentration differences between two Xanthoria species.
• To evaluate lichens as bioaccumulators of road pollution in semiarid environments.

Main Methods:

• Sampling of two lichen species (Xanthoria alfredii, Xanthoria ulophyllodes) and soil at varying distances from a road.
• Analysis of 42 elements using multielemental techniques.
• Calculation of Enrichment Factors (EFs) to determine element sources.

Main Results:

• Multielement patterns, Fe:Ti, and rare earth element ratios were similar between lichens and soil.
• Ten elements (Ca, Cd, Co, Cu, K, P, Pb, S, Sb, Zn) were enriched in lichens compared to soil.
• Elemental concentrations were generally higher in X. ulophyllodes than X. alfredii and increased with proximity to the road.
• Narrow-lobed sorediate lichens showed higher particulate entrapment efficiency.

Conclusions:

• Lichen elemental composition is significantly influenced by soil input and road traffic emissions.
• Xanthoria species serve as effective bioaccumulators for monitoring road pollution in desert ecosystems.
• Lichen species morphology impacts their efficiency in capturing airborne particulates.