ESR13 Natasa Skrbic

Project: Removal of natural toxins at groundwater fed water works

Principal supervisor: Dr. Sarah Christensen

Intro to project:

For a long period of time, focus of environmental organic chemistry has been on anthropogenic substances and their occurrences in the environment, particularly in ground and drinking water. However, it is estimated that approximately 99% of the toxic substances that humans are exposed to have a natural origin. Thus, there is a clear need to put great attention on this still not enough explored group of hazard substances.
Natural toxins are compounds that by definition have toxicological effects and their exposures can be orders of magnitude higher in anthropogenically affected ecosystems. This is chemically very diverse group of compounds encompassing tannins, coumarins, quinones, flavonoids, polyketides, terpenes, saponins, steroids, alkaloids, cyanogenic glucosides and glucosinolates. Natural toxins, such as phytotoxins, have been studied in food for decades, but little attention has been paid to their occurrence in the natural environment.
Bracken fern (Pteridium aquilinum) is a globally distributed plant species, which is long known for its toxicity and carcinogenicity toward livestock. Among the group of potent illudane carcinogens that have been identified from bracken, the most abundant is patquiloside (PTA), a nor-sesquiterpene glycoside. A recent study has shown that that PTA and its degradation product ptersoin B (PTB) are present in the surface water and pore water in the upper soil layers in bracken dominated areas in Denmark. It was found that a considerable pool of PTA can accumulate in the soil profile. These findings raised an important question whether local water sources supplied by either groundwater or surface water in bracken-infested areas may be at risk of ptaquiloside or even other natural toxin contamination.
The overall objective of this PhD project is to address these concerns. In particular, this project aims to understand if the natural toxins (e.g. ptaquiloside, cyanogenic glucosides and glucosinolates toxins) are present in the ground water that serves as a drinking water abstraction source in Denmark. Since natural toxins have not been detected in Danish drinking water sources, the effect of standard water treatment procedures has not been explored yet. Therefore, this study will also investigate natural toxin fate/removal through the water treatment processes.