Historical copper mining contamination assessed using dendrochemical analysis in Southeastern Sweden

Area of Science:

• Environmental Science
• Geochemistry
• Dendrochronology

Background:

• Heavy metal pollution from mining waste poses significant environmental risks.
• Traditional monitoring methods struggle with historical contamination assessment and cost-effectiveness.
• Dendrochemical methods offer a promising approach for reconstructing long-term pollution dynamics.

Purpose of the Study:

• To investigate temporal patterns of copper (Cu), nickel (Ni), and zinc (Zn) accumulation in European aspen tree rings.
• To assess the utility of dendrochemical analysis for monitoring historical heavy metal pollution near an abandoned mine.
• To explore the influence of soil and climatic factors on metal uptake in trees.

Main Methods:

• Analysis of Cu, Ni, and Zn concentrations in tree rings of 22 European aspens (Populus tremula) using energy-dispersive X-ray fluorescence (ED-XRF).
• Examination of soil samples for heavy metal concentrations and pH.
• Correlation analysis between tree-ring metal data, soil properties, and climatic variables (temperature, precipitation).

Main Results:

• Elevated copper levels were found across the study site, with considerable heterogeneity in both Cu and soil pH.
• Increased accumulation of Cu, Ni, and Zn was detected in tree rings, despite no significant correlation with soil metal concentrations.
• Tree metal uptake was more consistently influenced by temperature than precipitation, with increased uptake under warmer, wetter conditions and reduced uptake during drought.

Conclusions:

• Dendrochemical methods are effective for monitoring historical heavy metal pollution.
• Refined sampling strategies considering localized soil and climatic factors are crucial for improving the reliability of dendrochemical assessments.
• Understanding the interplay between climate and metal uptake enhances the interpretation of tree-ring pollution records.