In January 2022, the UK team at the National Oceanography Centre successfully completed their first sampling campaign in the River Thames.
Sampling sites at Thames river basin
- Lechlade (rural upper reaches)
- Dorchester on Thames (rural with urban influence)
- Upstream tidal limit (Hampton Court)
- Downstream tidal limit (Richmond)
- Central London (urban)
- Thames estuary
This campaign was divided into two parts:
- tidal and estuarine sampling
- freshwater sampling.
The first part of the campaign involved joining a sampling vessel used by the Environment Agency, who carry out monthly surveys at a range of sites in the tidal Thames. This collaboration enabled our scientists to access the three designated LABPLAS sites: in the estuary, in central London, and at the tidal limit.
The second part of the campaign involved taking a small boat to the designated sites in the freshwater Thames, sampling at three sites to account for urban and rural influences. The team were lucky to have calm and dry conditions at all times for sampling, although it was very cold!
Samples of surface water were collected using a custom-built pump-filter device enabling the filtering of hundreds of litres of water at each site, to collect microplastics greater than 10 µm in size. A Manta trawl was also used to collect particles greater than 335 µm in size, i.e. larger particles. This is a common method used in global surface water sampling efforts, and thus enables comparison with other studies.
Sediment and invertebrates were collected from the riverbed using grabs.
The sampling will be repeated with a summer campaign in July.
In the meantime, samples will be processed and analysed between different LABPLAS partners to determine microplastic concentrations within the different sample types.