Analytical Online Water Conference on Microplastics, COVID and PFAS

Taking place on 13th October the WWEM Water, Wastewater & Environmental Monitoring conference will be discussing the challenges involved with the laboratory analysis of microplastics, coronaviruses and PFAS.

Microplastics

Dr Richard Cross from UK CEH will provide the opening presentation, explaining that whilst a standard definition of microplastics has yet to be agreed, with the EC definition of a nanomaterial, microplastics may be considered as plastic particles smaller than 5 mm and greater than 100 nm. This presents an analytical challenge for the detection and quantification of microplastics in complex environmental samples, because no single method can successfully enumerate all possible polymer types, across the full size range.

Dr Cross will present his team’s experiences in sampling, method development, processing and analysis at 8 WTWs and 8 WwTWs over a 7 month period in the UKWIR project ‘Sink to River - River to Tap’ - the first study of its kind in the UK to develop a robust approach to sampling and detection of microplastic particles in the treated water cycle.

Dr Fay Couceiro from the University of Portsmouth (UK) will then discuss microplastics in the aquatic environment and their impacts on environmental and human health. This will encompass wastewater effluents, freshwaters and marine waters, the main microplastics types and their ability to act a vectors. She will explain that once microplastics are in environmental waters they are too difficult and expensive to recover so it is essential to identify appropriate interventions, and some of these will be discussed.

Coronaviruses

Dr Isobel Stanton from UKCEH will describe the TERM project in which levels of SARS-CoV-2 were monitored in school and prison wastewater as a non-intrusive means of coronavirus infection surveillance.

Previously, similar monitoring work has tracked antimicrobial resistance and the use of prescription drugs and illicit drugs excreted at a population level. Wastewater-based epidemiology enables the early identification of local outbreaks and facilitates targeted use of local clinical testing.

The project was able to inform both institutions and local health authorities on whether mass surge testing of the various populations was needed to identify cases. Whilst community testing has been important in helping to curb the spread of SARS-CoV-2, wastewater based epidemiology (WBE) methods can also play a complementary role by characterising the disease burden in the total population.

Dr James Hannan will then explain how virus quantification by RTqPCR, together with other biomarkers such as phosphorus, total nitrogen and pH can play an important role in WBE programs. He will also describe the ways in which analytical automation saves time and cost.

In the third presentation of this session, Zhugen Yang from Cranfield University will describe work on a paper-based device for rapid, on-site wastewater surveillance.

PFAS

The PFAS group of compounds consists of both perfluorinated compounds or perfluoroalkyl acids PFAAs, where all carbons are saturated with F atoms, and polyfluorinated compounds, where both fluorine saturated carbons and carbons with hydrogen bonds are present. Polyfluorinated precursor compounds biotransform to produce PFAAs as dead-end extremely persistent daughter products. The understanding of the fate and transport of these compounds in the environment is complex and challenging and will be discussed by Dr Ian Ross from Tetra Tech.

This large group of synthetic compounds known as ‘Forever Chemicals’ are growing in notoriety as a result of their toxicity, persistence and ability to bioaccumulate. Since the 1940s PFAS compounds have been used in a wide variety of consumer products and industrial applications because of their chemical and physical properties, including oil and water repellence, temperature and chemical resistance, and surfactant properties. PFAS have been used in firefighting foams, the manufacture of non-stick coatings for frying pans, food packaging, pharmaceuticals, pesticides, cosmetics, furniture and outdoor clothing, paints and photographic materials.

Dr Ross will describe how the concepts of in-situ generation of perfluroalkyl acids PFAAs via precursor biotransformation can be used to explain how significant PFAS mass remains hidden in source areas.

PFAA precursors are so named because they transform slowly over time through abiotic and biological processes to the PFAAs. There is a natural biological funneling in which a host of PFAA precursor compounds containing a range of perfluorinated alkyl chain lengths and functional groups, aerobically biotransform to persistent PFAA products.

The concepts of biological funneling show that PFAS behave significantly differently to other contaminants and management plans need to be adapted to adequately understand the fate and transport of these contaminants. Examples of plans from AFFF firefighting foam impacted sites will be presented, and the common breakdown products from PFAS in other sources, such as landfills and wastewater treatment plants will be described.

Geraint Williams from ALS will then describe the latest approaches to PFAS analysis.

He will focus on the analytical options available, explaining that PFAS present many challenges for laboratories because whilst they are ubiquitous in the environment, their detection limit requirements are very low. The number of PFAS determined by conventional analyses are limited because analytical standards are not available for these compounds.

The presentation will review common analysis approaches, as well as providing details of more advanced techniques including Total Oxidisable Precursor TOP Assay and Total Organic Fluorine TOF analysis. The webinar will also provide guidance on sampling, QA/QC requirements, and how to overcome the potential difficulties of cross-contamination at Environmental Quality Standards (EQS) limits.

Angelika Koepf from LCTech will describe recent regulatory updates in Europe and the USA. She will explain that analytically, the determination of PFAS using LCMSMS methods is challenging and not yet harmonised as it is for other POPs such as PCDD/PCDF, but sample preparation holds the same challenges for laboratories independent of regional regulation. Besides the requirement for solid-phase extraction clean-up with subsequent concentration, a key challenge is to keep the background of analytes as low as possible. Additionally, fluorocarbon materials, commonly used in laboratory systems, are prone to release small amounts of PFAS that significantly increase background levels.

The application of fully automated parallel sample preparation will be described, with multiple samples being processed at the same time.

The WWEM analytical conference is being organised by Prof. Gary Fones from the University of Portsmouth, who says: “Being a virtual and cost-free event will mean that delegates can dip in and out of the sessions of most interest, and we are therefore expecting increased participation from water sector professionals, regulators, environmental lobby groups, students, researchers and international participants. Registered visitors will also be able to watch the conference presentations on demand after the LIVE event.