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Published on: July 4, 2014
Biomonitoring trace element atmospheric deposition using lichens in China
Zh H Zhang1, Z F Chai, X Y Mao
1Institute of High Energy Physics, Chinese Academy of Sciences, Beijing.
Environmental Pollution (Barking, Essex : 1987)
|August 30, 2002
Summary
Early lichens from China show declining heavy metal pollution. Instrumental neutron activation analysis (INAA) revealed lower elemental concentrations over time, indicating reduced atmospheric deposition.
Area of Science:
- Environmental Science
- Geochemistry
- Ecology
Background:
- Epiphytic lichens are sensitive bioindicators of atmospheric pollution.
- Long-term environmental monitoring is crucial for understanding pollution trends.
- Remote areas can still be affected by transboundary atmospheric deposition.
Purpose of the Study:
- To determine elemental concentrations in preserved epiphytic lichens from southwestern China.
- To assess temporal trends in atmospheric heavy metal deposition from the 1960s to the 1990s.
- To evaluate the effectiveness of environmental policies in reducing pollution.
Main Methods:
- Instrumental neutron activation analysis (INAA) was used to quantify 32 elements.
- Analysis was performed on Parmotrema recticulatum samples collected in the 1960s, 1980s, and 1990s.
- Elemental concentrations were compared across different decades to identify trends.
Main Results:
- Concentrations of Ag, As, Ce, Cr, Cs, Eu, Fe, Hf, La, Nd, Ni, Sc, Se, Sm, Tb, U, Yb, and Zn showed a significant decrease over time.
- Overall elemental concentration levels in lichens declined, suggesting reduced atmospheric deposition.
- Spatial variations in elemental concentrations indicated differing levels of heavy metal deposition across sampling sites.
Conclusions:
- Atmospheric heavy metal deposition in southwestern China has been declining over the past decades.
- Epiphytic lichens serve as reliable historical archives for monitoring environmental changes.
- The observed decline suggests successful environmental management or reduced regional industrial activity.
