Modelling plastics and applications of biosensors to monitor pollution

Monitoring water pollution using molecular biosensors, Bangladesh

As part of the UK REACH project in Bangladesh (https://reachwater.org.uk/), OWN members Paul Whitehead and Cordelia Rampley (Oxford Molecular Biosensors) have been evaluating the new technology of molecular biosensors and how they might be used in water research and pollution/water toxicity issues. Biosensors provide a new way of measuring the environment using the idea that microbes will respond to chemical pollution by altering their metabolism. The team tweak the DNA to enhance the activity of the microbes and also add the DNA of a light emitting gene. The biosensor equipment can then be used to rapidly detect and monitor pollution in rivers and groundwater. (See www.omb.co.uk to understand more about this technology).

Figure 1. Water sampling points along the Turag, Tongi and Balu river systems in central Dhaka and biosensor toxicity data showing the pollution hot spots around this part of the city (lower plot)

Working with colleagues in Bangladesh at BUET (Bangladesh University of Engineering and Technology) we have been testing water samples to map toxicity and pollution. We have been comparing toxicity with direct water use along the Turag, Tongi and Balu rivers to assess health impacts. The idea is to assist the Bangladesh Government with restoration of the central Dhaka river systems, to improve water quality and people’s access to clean water, as well as enhance livelihoods along the river system.

Modelling microplastics in the River Thames basin

In a project funded by Oxford University and supported by DEFRA, Paul Whitehead, together with colleagues in Oxford and Associates Daniel Butterfield and Gianba Bussi, have created a new model of microplastics in rivers and applied it to the whole of the River Thames basin.

Figure 2. The eight sub-catchments used to apply the INCA Plastics model to the River Thames basin

The INCA Plastics model has been developed to simulate the transport and distribution of plastics in river systems. It forms a new element of the process- based and dynamic INtegrated CAtchments suite of flow and water quality models. The model has been set up for the Thames from the source at Cricklade to the downstream tidal limit at Teddington Weir. It uses 2008-2018 daily data and effluent discharges and sewage sludge to simulate flows and suspended sediment at various locations along the river.

Figure 3. Simulated and observed flows and suspended sediments at Kingston Upon Thames, for the period 2008-2018

Microplastics data from UKWIR studies have been used to estimate loads of plastics from these sources. A set of mitigation studies have also been undertaken to evaluate the impacts of controlling plastic discharges. Reducing plastic sources by 50% makes a significant difference to the loads of microplastics moving along the Thames.

Figure 4. Microplastics load (kg) moving down the River Thames at different locations for the period 2008-2018. Blue line shows load simulated by the model for existing conditions, and orange line shows alternative results under a mitigation strategy.

The OWN thanks The WRA Bulletin for providing the contents of this news item. The WRA Bulletin is a quarterly publication, and relies on contributions submitted by Partners, Associates and Consultants. The document is circulated by email, and published on the WRA web-site, aiming to keep the WRA network up-to-date with respect to current activities.

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