Isle of Wight river shows alarming levels of microplastics pollution

Research shows the estuary has on average double the number of microplastics than polluted rivers in China and India.

The report was written by Hampshire and Isle of Wight Wildlife Trust volunteer and University of Manchester graduate Liberty Turrell, who is from the Island.

• Read more: Meet the Islander who found shocking amounts of microplastics in the river Medina

She found an average value of 2,147 items of microplastic fragments per kilogram of dried sediment in mudflat segments within the Medina Estuary.

Medina Estuary (Image: IWCP) The report cites wastewater discharge from Combined Sewer Overflows (CSOs) as a major source of pollution - from Dodnor Lane and Fairlee.

In response, both Southern Water and the Environment Agency told the County Press the microplastics enter the marine environment from a number of sources.

Southern Water said it was important to note that microplastics enter rivers and seas from sources including road and industrial runoff, shipping and beach users.   

Liberty collected mudflat sediment from 16 sample sites, discovering fibres, fragments, and beads of microplastics. Microfibres were found at all 16 sites.

Mud at Medina River (Image: IWCP) The estuary is a Site of Special Scientific Interest (SSSI).

CSOs are in place as overflow valves to reduce the risk of sewage backed up by heavy rainfall, preventing sewage from flooding homes and businesses.

According to data published by the Environment Agency, the CSOs discharged wastewater into the upper estuary for 2,932 hours in 2023, over 225 total spill events. 

Southern Water said heavy rainfall in 2023 contributed to this figure.

Southern Water, which is responsible for the CSOs, said: "We, along with the wider water industry, our regulators and academics, are exploring the impact of microplastics on our environment.

"We need to understand their impact and how we can play our part in effectively treating and removing them from sewage. 

“We welcome any research into this important issue and are reviewing the findings of this latest publication.

“We are working hard to reduce storm overflows and our work on the Isle of Wight has cut 300 recurring spills in under two years.

"We will be expanding this work on a much larger scale through our £1.5bn Clean Rivers and Seas Plan that will harness nature-based and engineering solutions to reduce these further.

"We meet permits set by our regulators for treatment processes - often going above and beyond what is required - but want to work with our partners to tackle this emerging societal issue of microplastics which are present across the environment."

Liberty, who conducted the study as her undergraduate dissertation at the University of Manchester, said: “This research helps to resolve a global critical gap in the current studies of microplastics in estuaries.

"Unfortunately, the results are shocking.

"The severe contamination of estuarine environments affected by wastewater discharge takes place across the world and sadly this includes the Isle of Wight.

"The results clearly show the prevalence and abundance of microplastics found in the intertidal mudflat sediments highlights a severe contamination issue of the Medina Estuary.”

Professor Jamie Woodward at The University of Manchester added: “Microplastic contamination of the Medina Estuary is a concern because it is an area of ecological importance.

"The Medina Estuary receives high volumes of untreated wastewater from Southern Water assets."

The Environment Agency said: “We are aware that microplastics enter the marine environment from a number of sources, including from the breakdown of larger plastic items.

“Much of this material comes from sources on the land, including littering and poor waste management practices such as fly-tipping.

"It is important we all work together to ensure waste is disposed of correctly.”

An Isle of Wight Council spokesperson said it is working closely with the Environment Agency and Southern Water to reduce surface water flooding events and reduce the amount of water pollution running into the sea through sustainable drainage systems and other related measures.