Can we use a biosensor to detect water pollution in real-time?
by Roberta Carafa
The following Blog has been developed by one of the participant of the recent MCAA ECS Satellite event on Science Communication.
During the workshop, participants were invited to work on a scientific blog and submit their final piece to be published on the MCAA Blog.
The piece has been revised by a task-force of the MCAA Communication Working Group. Members of the team included: Maria Montefinese, Luisa Merz, Ashish Avasthi, Pradeep Eranti, Nicoleta Spînu, and Ruben Riosa.
Enjoy the piece!
Would you like to check water quality in real-time and receive an early warning in case contamination is detected? We think that is possible!
In 2021, 214 million tons of chemicals hazardous to health were produced (4% more than in 2020; 1% more than in 2019), along with 85 million tons of chemicals hazardous to the environment (6% more compared with 2020; 2% more than in 2019) (EUROSTAT). A fraction of these chemicals reach surface, ground, and marine waters in complex mixtures through different emission sources: industry, WWTPs, diffuse sources (leaching and runoff in agricultural fields, air deposition, etc). The data on chemical emissions in waters, from different reporting streams (the E-PRTR, the WFD and the WISE-SoE) are difficult to interpret, with apparent errors, inconsistencies and missing river basin districts (EEA Report No 18/2018). Water pollution impacts not only the ecosystem and humans, but also industry sector: for example, wastewater contaminated with pesticides, due to pesticides toxicity to microbes, cannot be treated by direct conventional biological treatment, but must undergo through additional pre-treatment by other physiochemical methods.
A proposal for the review of the Water Framework Directive has been released by the European Commission in 2022, in line with the objectives of the European Green Deal and the Zero Pollution Action Plan.
The specific objectives of this proposal are to:
1. Update the lists of pollutants affecting surface and groundwater by adding and removing substances and updating existing quality standards;
2. Improve the monitoring of chemical mixtures to better assess combination effects and take account of seasonal variations in pollutant concentrations;
3. Harmonise, wherever relevant, how pollutants in surface and groundwater are addressed across the EU;
4. Ensure that the legal framework can be more swiftly aligned with scientific findings to more promptly respond to contaminants of emerging concern;
5. Improve the access to, transparency and re-use of data, to enhance compliance, reduce administrative burden and improve coherence with the wider EU legal framework dealing with chemicals.
Are we ready to respond to these new strict requirements on water quality?
We developed a specific biosensor able to detect pesticides in water in an indirect way: by measuring their effect on algae. Classical analysis performed by technicians requires taking water samples and analyzing them in the laboratory, which is laborious, time-consuming, and not economical. Laboratory analysis of water samples is also restricted by the substances analyzed and the specific time the sample was taken. If we want to check water quality continuously, we cannot measure the substances directly but instead we can measure their toxic effects, for example, using a biosensor.
Biosensors are a combination of a living organism that changes some characteristics, when it gets in contact with pollutants, and a detector that can assess these changes.
The WATERSCAN water monitoring biosensor we developed measures the decrease in photosynthesis efficiency in microalgae in biofilm, caused by pesticides, even at very low concentration, measured by an innovative Pulse Amplitude Modulated fluorometer applied to detect changes in microbial biofilm structural and functional indicators. The device for monitoring toxic substances in water includes two chambers in series: a first monitoring chamber and a second reference chamber with a purifying filter (Figure 1). Thus, it is possible to establish a local comparison between a biofilm in contact with purified water from toxic substances and another biofilm with raw water and, with this, discriminate functional changes due to contaminants.
This specificity allows to rule out changes in the biofilm caused by other factors. For example, there are variations in climatic conditions that are not due to contamination but that cause changes in the biofilm functional parameters and, therefore, could generate false positives of contamination. The device also includes Passive Samplers to adsorb pollutants: in case of alert for contamination the adsorbents are extracted, analyzed, and tested on specific standard bioassay (such as LiBERA, ERα-CALUX, MELN for endocrine distruptors), giving further information about pollutants responsible of the alert.
The first project year is spent at European Commission-JRC (Italy) and dedicated to the standardization of the technologies, the second year at the international company AECOM for the final field validation in Spain. The project includes a secondment with a pilot study in Venice lagoon, at Thetis SpA (Italy).
This monitoring system is protected by a granted patent (WO2021205051) in Spain and Luxemburg. A new patent request (P202330495) has been submitted for the second prototype, with substantial improvements.
Title of the project: WATERSCAN project
PI: Roberta Carafa
This project received funds from the European Union’s Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement №801342 (Tecniospring INDUSTRY) and the Government of Catalonia’s Agency for Business Competitiveness (ACCIÓ) (Project ref.: ACE026/21/000093)
Part of the property of the patent belongs to URV (University Rovira y Virgili) of Tarragona (ES) and to LIST (Luxembourg Institute of Science and Technology) (LU).
