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Monitoring litter in the tidal Thames

Port of London Authority Litter Collectors

The PLA manages a network of litter collectors in the Thames which are positioned in key locations, between Greenwich and Putney, where the current and tidal stream carry the most litter. Floating rubbish is intercepted and collected on both the ebb and flood tide, which is collected for recycling and disposal. To quantify the positive impact of our litter collectors in the Thames, the tonnage of rubbish collected is monitored annually and published in our annual report. Between 2014 and 2020, over 200 tonnes of rubbish were removed from the river using our litter collectors and driftwood service. We continue to monitor these figures to understand how the quantity of litter in the river is changing.

In addition, we have also worked closely with university academics to analyse how the type of litter found in the collectors is shifting. In 2016, a study carried out in partnership with King’s College London, analysed the type and quantity of litter collected along the tidal Thames. The study found that plastic bottles represented a quarter of the debris entering the collectors in central London. Similarly, a recent study carried out in partnership with Durham University also identified that single-use items constituted approximately 60% of the debris type accumulating within the collectors. Both studies found that single-use plastic items were the most dominant form of waste entering the PDCs in central London.

Rapid Appraisal of Litter

The rapid appraisal of litter is undertaken to understand how the type and distribution of litter in the tidal Thames has changed over time. In partnership with Thames21, the rapid appraisal is carried out twice a year, usually in March and September. The survey is undertaken by river where each 250m stretch of foreshore is graded from A to D, with A represented no evidence of litter and D signalling a problem area. The survey also identifies whether the litter is transient (the type that moves with the tide, such as plastic) and immobile (like a shopping trolley or tyre). Our litter baseline for 2017 found 55% of the surveyed foreshore was graded B or above (predominately free from litter). The Thames Litter Strategy target is for 75% of the foreshore to be Grade B or higher by 2022. On average, between 2018 and 2021, 80% of the foreshore was Grade B or above.

Cleaning the Thames

Launched in 2020, our Cleaning the Thames website aims to connect volunteers with a riverside clean-up near them. The online interactive map also provides a way of volunteers recording the type and quantity of litter they collected during their clean-up, acting as a central hub for the storage of data. This data is then compiled into our interactive GIS map and can be used to report the benefits of all clean-ups, however small, for removing litter across the River Thames. 

Academic Partnerships

In the past, we have have worked with a number of university academics, NGOs and other organisations to undertake a number of studies on litter and water quality in the tidal Thames. For example, we have partnered with the Natural History Museum and Royal Holloway University for a study investigating the presence of microplastics in fish from the River Thames. Investigating and monitoring litter in the tidal Thames allows us to understand the issue in greater complexity. We have have published a non-exhaustive list of areas of interest in academic research – please contact our Environment Team to find out more.

Last updated: January 2022