Investigating the occurrence and biological effects of emerging contaminants in the environment

Summary

Per- and polyfluoroalkyl substances (PFAS) constitute a diverse group of synthetic organo-fluorinated compounds with a wide range of applications in firefighting foams, cosmetics, textile industry, polymer manufacturing, surfactants etc. These have entered the environment via a wide range of sources and uses, and some can further partially transform into species that are recalcitrant in the environment. Hence, they persist in the environment and are sometimes referred to as ‘forever chemicals’ that are not easily removed via typical pollution treatment facilities such as wastewater treatment plants (WWTP). These chemicals can therefore be detected in water bodies via effluent discharges, impacting water quality and organisms in water bodies. 

The potential for long range transport, persistence, bioaccumulation and toxicity of these PFAS have caused these chemicals to be designated as being of emerging concern, and restrictions were imposed on the use of some PFAS. They can impact on important biochemical pathways and can reach concentrations known to cause biological effects in exposed organisms. Negative reproductive and developmental effects have been linked to exposure to these chemicals and links with specific diseases (e.g. cancer and non-alcoholic fatty liver disease (NAFLD)) have been identified at epidemiological level. Furthermore, due to their diversity, nature and chemical properties, their analysis in environmental media is challenging. However, techniques that are mostly based on liquid chromatography tandem mass spectrometry (LC-MS/MS) have recently allowed for their detection at the typically low levels (ng/L) found in the environment. The sources, distribution, and risks of PFAS within a catchment are not yet fully understood, and in particular data are limited across Scotland.

Gaps still exist on the influence and significance of source pathways (e.g., landfill leachate and industrial waste), structural and physico-chemical properties of these compounds on their environmental fate and toxicity, which this project aims to investigate. Moreover, most monitoring programmes have focused on traditional grab sampling, which unfortunately does not provide information on the more environmentally relevant freely dissolved concentrations which delivers information on the bioavailability of these chemicals. Such time- weighted average concentration can be obtained when passive sampling approaches e.g., ChemCatcher or the polar organic chemical integrated sampler (POCIS) are integrated into sampling regimes. Spatial and temporal monitoring e.g., within a specific catchment, will also aid in the identification of the sources, levels and distribution of PFAS chemicals. Further, the biological effects of these compounds will be investigated in a whole organism to understand their biological effects and mode of action. Improved monitoring and understanding of biological effects can aid to further focus PFAS reduction efforts and identify potential risks to and receptors as well as contribute towards the development of appropriate environmental quality standards and monitoring strategies for emerging chemicals within a water regulatory framework.

Supervisors

Discuss this further with the potential supervisor for this research degree:

Research Themes

Find other Research Degrees in the same theme: