Approaching mercury distribution in burial environment using PLS-R modelling

Area of Science:

• Environmental Science
• Archaeology
• Toxicology

Background:

• Mercury's environmental cycle and toxicology are extensively studied.
• Historical mercury pollution necessitates understanding past trends for present-day context.
• Archaeological skeletons offer insights into past mercury exposure and loads.

Purpose of the Study:

• To investigate mercury distribution and accumulation in ancient burial soils.
• To elucidate the factors controlling mercury behavior within burial environments.
• To understand the role of decomposing human remains in mercury cycling.

Main Methods:

• A multi-sampling soil approach was used in two 5th-6th century AD burials.
• Principal Local Regression Smoothing (PLRS) modeling was applied to analyze mercury distribution.
• Analysis focused on the relationship between skeletal remains and soil mercury content.

Main Results:

• PLRS modeling explained 72% of mercury variance in the soils.
• Body decomposition was identified as the primary mercury source, altering soil properties and mercury retention.
• Mercury accumulation resulted from complex interactions between decomposing bodies and soil components.
• Variability in mercury levels correlated with proximity to the thoracic area and skeletal mass.

Conclusions:

• Decomposing skeletons act as both a source and temporary sink for mercury in burial soils.
• The fine soil fraction (silt + clay) is crucial for understanding mercury cycling in coarse-textured soils.
• Characterizing the burial soil environment is essential for comprehending soil-skeleton interactions in mercury cycling.