Lead availability in soils from Portugal's Centre Region with special reference to bioaccessibility

Area of Science:

• Environmental Science
• Environmental Chemistry
• Toxicology

Background:

• Previous biomonitoring identified elevated lead (Pb) pollution in Aveiro and Leiria districts, Portugal.
• Human health risk assessment often assumes contaminant uptake mirrors toxicological studies, which may not account for soil matrix embedding and limited bioavailability.

Purpose of the Study:

• To estimate the soluble fraction of lead (Pb) in central Portugal soils.
• To assess Pb bioaccessibility and infer human health exposure and risks.
• To investigate the relationship between soil physical-chemical properties and Pb solubility/bioaccessibility.

Main Methods:

• Estimation of soluble lead (Pb) fraction in soils.
• Assessment of Pb bioaccessibility using an in vitro gastrointestinal tract mimetic.
• Analysis of soil physical-chemical properties, including pH, and their correlation with Pb solubility and bioaccessibility.

Main Results:

• Relatively low total lead (Pb) concentrations were found in soils, with higher levels in the Aveiro district.
• Soils in Aveiro exhibited more soluble and geoavailable Pb forms.
• Higher soluble Pb concentrations correlated with increased Pb bioaccessibility, influenced by soil pH.

Conclusions:

• Lead (Pb) in central Portugal soils, especially in Aveiro, is more soluble and bioaccessible than total concentrations suggest.
• Soil properties, particularly pH, significantly influence Pb bioaccessibility and potential human health risks.
• The study highlights the need to consider Pb solubility and bioaccessibility, not just total concentration, for accurate risk assessment.