One of the most important challenges in the 21st century is the ability to provide a clean and pollutant-free source of water for a wide variety of uses. In Ireland, the threat to water quality can arise from a variety of fields of use, including toxicity from pesticides used in agriculture, heavy metals from manufacturing and antibiotics from both human and animal consumption. Although the quality of water in Ireland is generally good, the Environmental Protection Agency detected the herbicides MCPA in 55% of rivers monitored from 2013 to 2018 and 2,4-D in 29% of rivers monitored. Similarly, lead was detected in 14 Irish public water supplies in 2018. Accurately monitoring the status of water bodies with respect to these contaminants is currently a huge challenge. With this in mind, the project aimed to develop electrochemical- and optical-based sensors for detection of organic contaminants (herbicides) and heavy metals. Although further research and development is needed to optimise the developed technologies, it is hoped that the data provided by the sensors can help to identify pollution sources rapidly and allow appropriate measures to be taken quickly to limit pollution events.

Informing Policy

The overarching legislation this project falls under is the Water Framework Directive (WFD) and the relevant follow-up recommendations from the European Commission to expand environmental monitoring. The WFD is supported by more targeted directives, such as the Drinking Water Directive, which states that the limit for a single pesticide in drinking water is 0.1 μg/L and for the sum of all pesticides is 0.5 μg/L. The current statutory monitoring is based on discrete water sampling and might not provide a full picture of the status of water bodies. Continuous, in situ sampling solutions can capture daily and seasonal variability of pollutant concentrations, and can greatly aid relevant stakeholders to assess, manage and monitor the state of water systems, and ensure that the current policies are correctly implemented. If analytically sensitive enough, they can inform when an exceedance is repeatedly observed so that corrective measures can be undertaken. We believe that the present project has made significant strides in this context through the development and demonstration of proof of concept of several technology platforms and processes.

Developing Solutions

The UisceSense project resulted in a range of outputs and breakthroughs in the field, beyond the state of the art. The research carried out in this project has shed light on the potential for the development and optimisation of novel environmental sensors and anti-biofouling strategies. In particular, it has indicated the potential of electrochemical sensors for detection of heavy metals as well as surface-enhanced Raman spectroscopy for the detection of organic pesticides such as 2,4-D. To enable the deployment of such sensors, a number of antibiofouling strategies were also explored. The first aspect was to develop atomistic modelling to understand the biofouling processes. The second aspect was to experimentally study the anti-biofouling. This was done at both the sensor level – by protecting the electrode surface with a sacrificial layer – and the bulk surface level – by
functionalising the whole surface of the chip with an adsorbate suitable for hindering or even prohibiting the growth of potential biofouling organisms.