Temporal trends in metal pollution: using bird excrement as indicator

Area of Science:

• Environmental Science
• Ecotoxicology
• Biomonitoring

Background:

• Mining and smelting cause widespread metal pollution.
• Long-term monitoring data, especially for higher trophic levels, is often limited.
• Terrestrial metal pollution requires effective and sustained monitoring strategies.

Purpose of the Study:

• To assess the utility of bird excrement for long-term metal pollution monitoring.
• To evaluate metal pollution trends in terrestrial environments near a copper/nickel smelter.
• To understand the relationship between atmospheric emissions and metal concentrations in bird excrement.

Main Methods:

• Utilized excrement from Great Tits (Parus major) and European Pied Flycatchers (Ficedula hypoleuca) over 16 years.
• Analyzed lead and cadmium concentrations in bird excrement.
• Correlated excrement metal data with smelter emission data and soil metal contributions.

Main Results:

• Significant decreases in lead and cadmium were observed in bird excrement in the early 1990s.
• Excrement metal reduction did not precisely mirror atmospheric emission reductions.
• Soil metal pools contributed to observed excrement concentrations, indicating a delayed or buffered response.
• Inter-annual variations in copper and nickel highlighted the need for continuous monitoring.

Conclusions:

• Bird excrement is a valuable tool for assessing broad environmental changes in metal pollution.
• It is less effective for directly tracking short-term atmospheric emission fluctuations.
• Long-term monitoring of bird excrement is crucial for identifying significant environmental trends amidst inter-annual variability.