ESR10 Regiane Sanches Natumi – University of Copenhagen

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ESR10 Regiane Sanches Natumi

Project: Stability of natural toxins in surface waters

Principal supervisor: Dr. Elisabeth ML Janssen

Intro to project: Secure high quality drinking water is a crucial task and is a topic of great concern to public authorities. Several parameters need to be controlled to provide clean drinking water and one of them is the presence of pollutants. Until now the research focus is lying on the presence of anthropogenic pollutants, such as pesticides and pharmaceuticals, while the presence of toxic compounds of natural origin are being mostly neglected. One of the aims of the NaToxAq network is to assess the risk of these emerging natural toxins for human health from theirs source to the tap, i.e., to the drinking water. Risk is defined as the probability of an adverse outcome based on the exposure and hazard of the compounds, being hazard the potential of a substance to cause damage. Consequently, to perform the risk assessment of a certain substance it is important to know not only its toxicity but also the extend of exposure the human population experiences.  Therefore, it is necessary to study the stability of natural toxins of concern in the environment to determine whether or not the compound can pose a threat to drinking water resources.

In this context, my PhD project will focus specifically on the stability of emerging natural toxins and in particular waterborne cyanopeptides that can be potentially toxic to animals and humans. Cyanopeptides are a structurally diverse group of compounds that are secondary metabolites of cyanobacteria, a photosynthetic prokaryotic microorganism also known as blue-green algae. The most studied class of cyanopeptides is the group of microcystins,  hepatotoxins known for being the cause of numerous animal and human intoxication by inhibition of the protein phosphatase PP1A and PP2 (Merel et al., 2013). Recently, other classes of cyanopeptides such as cyanopeptolins were reported to be toxic to crustaceans and to be inhibitors of serine protease (Gademann et al., 2010). However there is not much information available regarding the toxicity and properties of many other cyanopeptide classes. During my PhD, I will focus on the stability and possible transformation processes of such novel cyanopeptides by determination of photochemical transformation mechanisms, sorption, and biodegradation processes. The final goal is to improve our understanding of the stability of these novel cyanopeptides in the aquatic system and to improve risk assessment for environmental and human health.