“Very high” levels of E coli found in oysters and mussels have led to the closure of 11 shellfish production zones in Cornwall.
In an email seen by the Guardian and Watershed Investigations, the Cornwall Port Health Authority (CPHA) told food business operators they “must not collect the affected animals from this area by any method. It is unsuitable for their production for health reasons and has been temporarily closed.”
The main sources of faecal contamination are generally agriculture, sewage and urban pollution, according to the Environment Agency.
Levels of E coli are measured per 100g of flesh. For a shellfish area to be considered “class A”, which means no cleaning of the produce is required before sale, 80% of samples must contain less than or equal to 230 E coli bacteria/100g. Shellfish from areas that breach this limit have to be extensively treated and the sale of those from areas where levels exceed 46,000/100g is prohibited.
In the 11 closed areas around the rivers Fal, Truro and Carnon, the E coli levels reached up to 92,000/100g. The CPHA said the readings were very high and that anyone who continued to harvest shellfish from these areas faced fines or imprisonment for up to two years.
The shellfish industry is furious with the government for not tackling the problem sooner.
James Wilson, a water quality project manager from the Shellfish Association of Great Britain, said: “The industry has been saying to government for years that we need to clean up our waters. We’re constantly fobbed off [and] it constantly gets worse.
“We shouldn’t turn our waters and seas into a sewage dumping ground. We should be growing more stuff in the sea. There’s lower climate change impacts to producing oysters compared to other animal proteins but we’re doing less and less of it, certainly in comparison to neighbouring countries.”
The industry has had to learn to work around pollution caused by other sectors.
Martin Laity, a Cornish oyster producer, said: “We know when to harvest, we know when the rivers are dirty … and we’ve never poisoned anyone. But how the hell did the water companies get permission to [dump raw sewage]?”
Laity said he did not know who was responsible for the E coli problem, but added: “There are so many incidents up the river of the water company spilling … if you fly-tipped in a river you’d be arrested.”
Analysis by the Guardian and Watershed of five years of E coli levels in oysters, showed that each year, less than a quarter of the areas tested would meet class A criteria, meaning the majority of the shellfish harvested would need to go through costly additional cleaning processes before they could be sold.
Wilson said: “Depuration is where the oysters are treated by UV light so all the bacteria is taken out – the higher the levels of E coli, the longer the oysters have to be cleaned. It’s expensive, you’re running pumps and UV lights and it all costs, especially with rising energy bills.”
The biggest impact is one of perception, he added. “When you see the shit coming down rivers into the sea, people wonder: do I really want to eat that? Whether it’s been depurated or not.”
Joan Edwards, the director of policy and public affairs at the Wildlife Trusts, said: “We are seeing announcements about investment to reduce sewage spills, and in parallel we need support and incentives for farmers to reduce their impacts on our rivers and coasts – and in both sectors, this must be underpinned by better monitoring and enforcement where practices are slow to change.”
A spokesperson for the industry body Water UK said water companies planned to spend £10bn over the next seven years on “an intensive programme to improve sewage overflows”. The sum was triple today’s levels of investment and was “part of the biggest modernisation of sewers since the Victorian era”, they said, adding: “Action on water quality will be prioritised in sensitive areas.”
Alex Ford, a professor of biology at Portsmouth University, said the high concentrations of E coli suggested there may be other problematic substances in the water that were not being routinely measured.
“Indirectly, these faecal coliforms act as an indicator to warn us about many other chemicals which are being discharged into our rivers and coasts. These pollutants that you can’t see can have negative impacts on the health of wildlife,” said Ford.
A spokesperson for the Department for Environment, Food and Rural Affairs said: “We work closely with partners to monitor shellfish sites, and we have been clear with water companies that the ongoing pollution of our rivers and beaches is unacceptable. That’s why we’ve set the strictest targets ever on water companies to reduce discharges and required them to deliver the largest infrastructure programme in their history – with £56bn capital investment over 25 years.”
