Optimising analytical methods for chlorinated paraffins to evaluate their occurrence in Australia

This PhD thesis presentation focusses on advancing the capabilities of analysing chlorinated paraffins (CPs) in order to allow a first evaluation of their levels in the human population of Australia.

More specifically, it had three goals. First, it provides an update what is known about CPs and what the current capabilities are in analysing them -including key challenges. This was conducted by two literature reviews and four interlaboratory exercises (ILS). Secondly it tried to improve these current capabilities by addressing one of the key challenges and optimising and evaluating different instrumental techniques to identify the most suitable one. These include the most commonly applied (GC-ECNI-qMS) and novel promising techniques (APCI-QToF-MS and GCxGC-µECD). APCI-QToF-MS was found the most suitable technique and therefore will be applied later this year to achieve the third goal: provide information about their levels in Australia, a country where CPs are produced but for which information about them -including their levels- is lacking.

CPs are polychlorinated n-alkanes with a chlorine content between 30 and 70% on weight basis, used in many applications such as metal drilling, plasticizers and flame retardants. Their annual production volume is over 1 million tonnes, about equal to the total world production of polychlorinated biphenyls (PCBs) ever. This production is still increasing, especially in China. Based on their carbon chain length, CPs exist as short, (C10-13), medium (C14-17) and long (C>18) chained CPs. Because of their widespread presence in the environment as well as their persistent, bioaccumulative and toxic properties, short chained CPs (SCCPs) are classified as persistent organic pollutants (POPs) by the UNEP Stockholm convention since 2017 and on several other monitoring lists such as the European Water Framework directive, in order to monitor them regularly in the European environment. Less is known about the environmental levels and persistent, bio-accumulative and toxic characteristics of medium chained CPs (MCCPs) and long chained CPs (LCCPs), impeding international classifications and regulations.

This is mainly due to the challenges that arise in determining CPs. The main challenges are their relatively low response on detection systems, interferences with other halogenated compounds and the separation and quantification of the congener groups. Other challenges include the lack of certified reference materials (CRMs) to validate methods and suitable individual standards to quantify with. Although SCCPs have been analyzed since the early 1980s, only a limited number of laboratories exist that have the expertise to analyses them. Analysis and quantification is far from standardized and concentrations are reported as total SCCPs, with high variability between laboratory results.

Presenter:

Ms Louise Van Mourik, QAEHS PhD Candidate; Thesis Review