Nowadays, likely tens to hundreds of thousands of anthropogenic chemicals are dispersed in the aquatic environment, and only a small fraction is regularly monitored. These chemicals belong to very diverse classes, and they are generally referred to as contaminants of emerging concern (CECs). They are mainly pharmaceuticals and personal care products (PPCPs), UV filters, UV stabilizers, pesticides, plasticizers, drugs of abuse, and other industrial chemicals. Moreover, CEC transformation products (TPs) are studied since they could be even more toxic than the parent compounds.
Besides PPCPs, pesticides, herbicides, etc., other important CECs are the perfluoroalkyl substances (PFASs). PFASs are a group of man-made chemicals; their fluorinated alkyl chains confer persistence and water/grease-repellent properties. There are over 4000 known PFASs, and for most of which there is little to no information about their fate/transport, exposure, and toxicological effects.
The aim of this project is the development of an analytical platform for the identification of the main CECs, in particular PPCPs and PFASs, in surface water. Also, their potential TPs will be investigated.
The first step will be the optimization of a solid phase extraction (SPE) protocol for the target compounds, namely PPCPs, drugs of abuse, and PFASs, together with their metabolites and TPs. Different SPE sorbents will be compared in terms of global recovery efficiency.
For the determination of these CECs, liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) will be used. Indeed, this allows untargeted analysis, as required when the presence of certain compounds is only suspected or even unknown. Then, a customized workflow for data interpretation will be used to tentatively identify as many CECs as possible and their TPs in river water samples with an acceptable confidence level.
Nowadays, the monitoring of environmental waters is an urgent challenge. Indeed, thousands of anthropogenic chemicals are dispersed in the aquatic environment, even if most of them at very low levels. Nonetheless, it is important to assess their presence for possible national and European regulation. In fact, many of these compounds are pharmaceuticals, mainly antibiotics, whose presence can enhance antibiotic resistance.
Because these chemicals belong to very diverse classes, it is difficult to find a single analytical method for their determination. In this project, our aim is to find out an approach to detect not only the precursor substances, but also their possible transformation products. Transformation products can derive from human body metabolism, wastewater treatment plants activity or environmental degradation, and could be even more toxic than their precursor; they are generally more polar than parent compounds and their structures are not always easily predictable.
To obtain the knowledge of the levels of CECs and their transformation products in the surface waters in a selected area could provide useful information for future monitoring, as well as to increase the efficiency of wastewater treatment plants towards some compounds.
For PFAS this is even a more challenging task, since there is not a general consensus yet on their definition, they are widespread in every environmental compartment and are highly persistent and tend to bioaccumulate by binding to plasma proteins. In this project, our ambitious aim is to find a method to semi-automatically detect a wide range of PFAS and their derivatives, to make easier their monitoring in environmental samples.