The aim of this project is to develop a reliable electrochemical sensor for the easy and reliable determination of arsenic in groundwaters.
Arsenic contamination of groundwaters is a worldwide issue (including the UK). In Bangladesh and India alone, several million people are exposed on a daily basis to unsafe arsenic intake through drinking water and food, leading to disease, cancer and ultimately death1. The extent of the issue is huge with the presence of millions of tube wells. Arsenic levels are difficult to predict; in fact, they have been found to vary significantly both spatially and temporally, depending on the geology, the well depth or amount of water being drawn out.
The lack of analytical capabilities in rural communities means that the most common way of testing the water is to sample an aliquot, store it and send it to an analytical laboratory for later analysis. The is far from ideal in light of the large number of wells that need to be regularly tested. Cheap, rapid and simple on-site determination of arsenic in groundwater using miniaturised portable systems is a better option but there are yet no such systems. This project aims to remediate this.
In Liverpool, we published several methods on the determination of arsenic in marine and freshwater systems 2-6. Although simpler than previous methods, they still suffer from analytical limitations that limit their use to “experts”, capable of adapting the methodology to suit the type of sample matrix; the experimental procedure is currently not suited to non-experts and this is the challenge that needs to be tackled.
To achieve this aim, 3 goals needs to be achieved:
- Increase the linear range of both arsenite and arsenate. Here, we will focus on increasing the electroactive surface while maintaing a low background current. A few methods will be tested, based on a literature review, including on the use of gold nanoparticles. There is scope here for the student to benefit from the presence of the MIF expertise. (https://www.liverpool.ac.uk/materials-innovation-factory/
- Minimise voltammetric interferences, mostly from organics. Dissolved organic substances are present in groundwater and do perturb the analytical measurement. Various methods have been reported in the literature and the student will be expected to adapt some of them for the analysis.
- Test the new sensor during field campaigns in West Bengal, India and other contaminated locations (e.g. Mexico) to assess the ease of use and the reliability of the sensor in varying biogeochemical conditions. Analysis will be corroborated by alternative techniques such as HG-AFS. We expect a total fieldwork campaign of approximately 3 months over the course of the PhD.
To apply for this opportunity, please visit: https://www.liverpool.ac.uk/study/postgraduate-research/how-to-apply/
and click the ’Apply now’ button.
(1) Bhowmick, S.; Pramanik, S.; Singh, P.; Mondal, P.; Chatterjee, D.; Nriagu, J. Science of the Total Environment 2018, 612, 148-169.
(2) Cheng, A. R.; Tyne, R.; Kwok, Y. T.; Rees, L.; Craig, L.; Lapinee, C.; D'Arcy, M.; Weiss, D. J.; Salaun, P. Journal of Chemical Education 2016, 93, 1945-1950.
(3) Salaün, P.; Gibbon-Walsh, K. B.; Alves, G. M. S.; Soares, H. M. V. M.; van den Berg, C. M. G. Anal. Chim. Acta 2012, 746, 53-62.
(4) Gibbon-Walsh, K.; Salaün, P.; Uroic, M. K.; Feldmann, J.; McArthur, J. M.; van den Berg, C. M. G. Talanta 2011, 85, 1404-1411.
(5) Alves, G. M. S.; Magalhaes, J. M. C. S.; Salaün, P.; van den Berg, C. M. G.; Soares, H. M. V. M. Anal. Chim. Acta 2011, 703, 1-7.
(6) Gibbon-Walsh, K.; Salaün, P.; van den Berg, C. M. G. Anal. Chim. Acta 2010, 662, 1-8.