Abstract
Introduction: Events of drought and higher temperatures are occurring more often. This, together with the increased use of fertilizer in agriculture, are leading to environmental eutrophication and shortage of freshwater reservoirs. Eutrophication of our water bodies can lead to several disrupting events such as Harmful Cyanobacterial Blooms (HCB) that can release natural occurring pollutants such as cyanotoxins. Globally, more than 70% of water used for agriculture is groundwater and surface water. However, irrigation water-quality standards suffer from a lack of regulation worldwide. When episodes of water scarcity occur, vulnerable communities may be forced to irrigate their crops with cyanotoxin-polluted water. Consequently, indirect or direct human consumption of cyanotoxins happen, which may lead to several cytotoxic pathologies.
We propose the application of vertical flow (VF) constructed wetlands (CWs) as a biotechnology to treat water for irrigation. The hypothesis is that VF systems can remove cyanotoxins while preserving the nutrients from the eutrophic water. Although initial studies suggested CWs to be a suitable technology, in this respect, the mechanisms underlying cyanotoxins removal are still unknown. Our hypothesis is that members of the native microbiota are responsible for degrading the cyanotoxins.
Methods and data: We set up thirty-two 12-L unsaturated VF-CW systems with three different treatments: 1) gravel vs. Sand; 2) Phragmites australis vs. Juncus effusus, and 3) presence vs. absence of cyanotoxins. Synthetic water mimicking eutrophic surface water (containing 10 µg/L of microcystin-LR and cylindrospermopsin) fed the mesocosms systems. We are currently measuring end-point quality water parameters (TOC, TN, pH, cyanotoxins concentration), and characterizing the microbial community using 16S Amplicon DNA sequencing to see how the community is responding to the treatments, seasonal change and degradation efficiency.
Results: After almost one year of operation, several variable co-relations were found that explained the cyanotoxin removal in our systems. Besides, initial data on the microbial community structure will be discussed at the conference.
Discussion and take-home message: Data is still preliminary, but we hope that by the end of the project we can demonstrate how CWs can alleviate cyanotoxin contamination in surface waters for the benefit of human and animal health, including the mechanistic understanding of the biodegradation process.
We propose the application of vertical flow (VF) constructed wetlands (CWs) as a biotechnology to treat water for irrigation. The hypothesis is that VF systems can remove cyanotoxins while preserving the nutrients from the eutrophic water. Although initial studies suggested CWs to be a suitable technology, in this respect, the mechanisms underlying cyanotoxins removal are still unknown. Our hypothesis is that members of the native microbiota are responsible for degrading the cyanotoxins.
Methods and data: We set up thirty-two 12-L unsaturated VF-CW systems with three different treatments: 1) gravel vs. Sand; 2) Phragmites australis vs. Juncus effusus, and 3) presence vs. absence of cyanotoxins. Synthetic water mimicking eutrophic surface water (containing 10 µg/L of microcystin-LR and cylindrospermopsin) fed the mesocosms systems. We are currently measuring end-point quality water parameters (TOC, TN, pH, cyanotoxins concentration), and characterizing the microbial community using 16S Amplicon DNA sequencing to see how the community is responding to the treatments, seasonal change and degradation efficiency.
Results: After almost one year of operation, several variable co-relations were found that explained the cyanotoxin removal in our systems. Besides, initial data on the microbial community structure will be discussed at the conference.
Discussion and take-home message: Data is still preliminary, but we hope that by the end of the project we can demonstrate how CWs can alleviate cyanotoxin contamination in surface waters for the benefit of human and animal health, including the mechanistic understanding of the biodegradation process.
| Original language | English |
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| Publication date | Apr 2022 |
| Publication status | Published - Apr 2022 |
| Event | Danish Water forum - , Denmark Duration: 20 Apr 2022 → … |
Conference
| Conference | Danish Water forum |
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| Country/Territory | Denmark |
| Period | 20/04/2022 → … |