Reconciling PM10 analyses by different sampling methods for Iron King Mine tailings dust

Area of Science:

• Environmental Science
• Toxicology
• Geochemistry

Background:

• Superfund sites like Iron King Mine pose risks from heavy metal exposure.
• Tailings piles can release size-fractioned dust impacting proximate populations.
• Research requires reliable methods for characterizing and sourcing environmental contaminants.

Purpose of the Study:

• To develop a robust method for identifying the source of heavy metals in dust.
• To compare dust samples generated from tailings with those collected in situ.
• To quantify the contribution of Iron King Mine tailings to ambient PM10 dust.

Main Methods:

• Utilized a dust generator to produce size-fractioned tailings dust.
• Employed a MOUDI (Micro-Orifice Uniform Deposit Impactor) sampler for ambient dust collection.
• Applied a single element concentration method for source apportionment of arsenic (As) and lead (Pb).

Main Results:

• PM10 fraction of MOUDI samples showed lower As and Pb concentrations than dust generator samples, indicating dilution.
• The single element concentration method concluded that nearly all As and Pb in PM10 originated from Iron King tailings.
• As and Pb exhibited similar mass fractions from Iron King across all sites, suggesting a common emission source.

Conclusions:

• The developed method effectively identifies Iron King Mine tailings as a primary source of As and Pb in PM10 dust.
• Dilution of tailings dust by other sources was observed in ambient samples.
• Further validation of the source apportionment method with additional elements and sites is recommended.