High Resolution Mass Spectrometr: new methods of analysis for risk assessment by cyanotoxins and cyromazine in water for human consumption

The recent implementation of the EU Directive 1787/2015 introduced in Italy the Water Safety Plan (WSP), a preventive model to guarantee drinking water through control measures extended to the entire water supply chain, from collection, treatment and distribution to the user. In this context of prevention, protection and monitoring of the quality of water intended for human consumption, it becomes important to develop analytical methods that allow the search for an increasing number of contaminants that could be present in the water, with particular attention to substances considered emerging contaminants (EPs). EPs encompass a wide range of natural and man-made chemicals which are in use worldwide and which are indispensable for modern society, that currently are not included in routine monitoring programmes but that could have nocive effects on human health. In particular, among the emerging contaminants, my attention has focused on the secondary metabolites of cyanobacteria and on Cyromazine, a pesticide used as a drug of abuse, for two different reason: - the proliferation of cyanobacteria in water used for human consumption is an emerging issue in Italy in recent years, involving almost all the Regions, with potential impact on environmental and human health. Changes induced, directly or indirectly, by human activity in surface water bodies preside over, in fact, an abnormal proliferation of constituent bodies of aquatic biota, can cause undesirable or toxic metabolites (cyanotoxins), to affect the quality of water and cause a significant health risk - that requires proper management - water for the supply chain for the production of drinking water. - the recent issue of a press release by the Directorate General for Hygiene and Safety of Food and Nutrition regarding the revocation of the authorizations of plant protection products containing the active substance cyromazine, following the expiry of its Community approval period pursuant to Regulation (EU) 844/2012. In the first part of the research work of this PhD, an analytical method of solid phase extraction (SPE) and subsequent determination in ultra-high performance liquid chromatography (UPLC) coupled to a high resolution mass spectrometer (QTOF) for the simultaneous determination of 21 cyanotoxins in water for human consumption was developed. The method was then validated and applied during a monitoring activity in an Italian volcanic lake in Viterbo (Lazio Region, Italy), due to a severe algal proliferation in January 2018 – January 2020 period. Obtained results were used for the assessment of cyanobacteria proliferation risk and of cyanotoxin production in drinking water chain. The development of another analytical method without SPE for the determination of further two cyanotoxins has been started but the method is not complete and needs a further optimization step. As final step a method for the identification and quantification of cyromazine in drinking water samples used in chicken coops was developed and validated.