Investigation of source apportioning for alpha-HCH using enantioselective analysis

Area of Science:

• Environmental Chemistry
• Chiral Analysis
• Persistent Organic Pollutants (POPs)

Background:

• Chiral compounds exhibit enantiomeric forms, which can be used to trace their origins.
• Alpha-hexachlorocyclohexane (alpha-HCH) is a persistent organic pollutant with known chiral properties.
• Understanding the distribution and sources of alpha-HCH is crucial for environmental risk assessment.

Purpose of the Study:

• To investigate the utility of enantiomeric analysis for source apportionment of alpha-HCH.
• To determine how geographic factors influence the enantiomeric signatures of alpha-HCH in environmental samples.
• To correlate enantiomeric fractions (EFs) with environmental conditions and concentrations.

Main Methods:

• Analysis of archived air, water, soil, and grass samples using enantioselective techniques.
• Deployment of passive air samplers across Europe and along an Atlantic transect.
• Measurement of alpha-HCH enantiomers and calculation of enantiomeric fractions (EFs).

Main Results:

• Enantiomeric signatures of alpha-HCH varied significantly based on proximity to water bodies (Baltic vs. Mediterranean air).
• Latitude strongly influenced alpha-HCH EFs in Atlantic air, with a clear north-south gradient.
• Inland air samples showed racemic signatures at high alpha-HCH concentrations, with increasing variability at lower concentrations.

Conclusions:

• Enantiomeric analysis of alpha-HCH provides valuable complementary information for source apportionment.
• Geographic factors, including latitude and proximity to water, are key determinants of alpha-HCH enantiomeric signatures.
• The study demonstrates the potential of enantioselective analysis for tracing POPs distribution and identifying emission sources.