Analytical approaches for the assessment of human exposure to polyhalogenated alkanes (PXAs)

Chlorinated paraffins (CPs) are polychlorinated linear chain alkanes with high production volumes used as flame retardants and plasticizers in a wide array of consumer goods. CPs may be released from treated goods and have become widely distributed in the environment and human tissues.

Humans are exposed to CPs via contaminated indoor dust and food, while certain CPs have been registered as United Nations Persistent Organic Pollutants (POPs) and their usage restricted due to well documented toxic and bioaccumulative properties.

Recent evidence has suggested that banned CPs may have been replaced by compounds known as polyhalogenated alkanes (PXAs), which share very similar chemical structures to CPs, differing only by the addition of bromine atoms. Both CPs and PXAs comprise of mixtures of thousands of isomers, making analysis and quantification highly complicated.

A recent pilot study of PXAs in indoor dust revealed that the replacement compounds may be present at similar levels as banned CP groups.

Based on the physicochemical similarities, PXAs are predicted to share similar bioaccumulative and toxic properties as banned CPs, but have not been studied widely.

This research projects aims to develop the first analytical procedures for quantification of PXAs in indoor dust and generate methods for assessing the occurance of PXAs in a variety of environmental matrices.

Measurements in indoor dust samples from Europe and the United States of America will be used to conduct a world-first human exposure assessment for PXAs.

Developed methods will then be applied for retrospective screening of PXAs in archived data files to provide a broad snapshot of PXA contamination in food and the environment for the first time.

The outcomes of this project are intended to characterize the current contamination status of PXAs in indoor dust, food and the environement with the objective of public health protection against potentially hazardous chemicals.