Windermere algal samples exceed WHO threshold for recreational use

Samples taken by Save Windermere at Waterhead, Ambleside, demonstrated cyanobacteria concentrations that exceeded the WHO guidance for activities such as swimming in the lake.

This is the second time in two years the campaign deemed the risk to human health as a justifiable reason to undertake independent sampling at Waterhead. 

READ MORE: Confirmed blue green algal bloom spotted in Windermere

On June 25, Save Windermere was alerted to a Blue-green algal bloom at Waterhead, described as extensive. On arrival, the bloom extended roughly 100m along the shoreline, stretching between five to 10 metres into the lake, with people swimming in the water. The campaign took four samples: three along the worst affected area of the bloom and one away from the worst affected area, which at the time of sampling was deemed un-impacted by the bloom.

The three samples taken in the worst affected area were above the EA Warning (signing) threshold of 500-700 gyres/ml and the WHO Recreational Limit of 100,000 cells/mL, at 666,846 cells/mL, 772,182 cells/mL, and 809,298 cells/mL.

The fourth sample was still above the EA warning threshold, despite appearing less impacted, but was below the WHO recreational limit. Toxin analysis was also undertaken on the samples. In this case, toxins were not being produced at the time of analysis. However, expert consensus is that BGA produces toxins 60 to 70 per cent of the time when a bloom is present.

The samples were analysed by Dr Nick Everall, ex-Principal Biologist at Severn Trent Water and registered expert witness.

Campaigners said the analysis reaffirmed Save Windermere’s stance that the Environment Agency’s monitoring, warnings, and actions with regard to BGA on Windermere are inadequate, not fit for purpose and pose a risk to public health.

The area sampled is not classed as bathing water but is used frequently for recreational activities, including swimming. It is also a known hotspot for BGA. Thus Save Windermere calls for permanent signage to be instated and for regular monitoring by the Agency to be undertaken throughout the summer season across the whole lake.

Save Windermere returned to the same location on June 26, and the bloom had dissipated, emphasising the need for routine monitoring of the lake.

Save Windermere has previously challenged bathing water quality classifications on Windermere, claiming they are misleading, with the absence of sampling and monitoring of BGA being a primary reason for this.

The campaign believes that all sites where there is public access to the lakeshore should have mandatory warning signs throughout the summer months to ensure bathers can make an informed decision about entering the water.

Although BGA can be potentially fatal to humans, cases of human fatality are rare as most humans do not drink raw water from surface waters and ingestion of the quantity required would likely only occur in an incident of drowning. Domestic animal poisoning is more common, for example in dogs and cattle, which can take in large amounts of poisonous algae when drinking or, in the case of dogs, cleaning their coats of scum after swimming in algal laden margins of lakes and ponds.

Save Windermere deems all previous investments by United Utilities to be insufficient to ensure the lake is adaptable to climate change. Despite previous reduction of phosphorous concentrations, United Utilities is still the single largest input of the nutrients that feed algae growth in Windermere. This comes after United Utilities paid the highest dividend in the country last year at £454 million.

An Environment Agency spokesperson said: “We are absolutely committed to improving the water quality in Windermere, which is affected by pollution from different sources, including wastewater treatment works, storm overflows, septic tanks and road and agricultural run-off.

“We continue to work closely with the local community and a range of partners to reduce pollution from all sources, as well as reviewing wastewater treatment works permits within the Windermere catchment. If any water company is found to be in breach of an environmental permit, the Environment Agency will take the appropriate enforcement action up to and including a criminal prosecution.”

A United Utilities spokesperson said: “Over the last two decades, we have invested £75 million upgrading wastewater treatment sites, pumping stations and sewers around Windermere, with £45 million of that work completed in 2020. Total phosphorus in Windermere has reduced by 30% as a direct result of that investment.

“We are investing a further £41 million into the Windermere catchment between now and 2030 to reduce storm overflow operation at Elterwater, Hawkshead, Ambleside and Near Sawrey by 50% on 2022 figures. This is expected to reduce total phosphorus by a further 4% and 8% in the two basins of Windermere. We continue to work with all organisations that impact water quality in the lake including farmers, septic tank owners, hotels, campsites, highways authorities and landowners to deliver the step change that we all want to see.”