Environmental Report ESSC August 2023
Environmental Report ESSC
There has been a lot in the news about pollution in Chichester and Langstone Harbour, but until now there has not been extensive testing to fully understand the effect of sewage discharges in the water we sail in.
With this in mind Project Spotlight was initiated by the Clean Harbour Partnership spearheaded by Rob Bailey, bringing together a coalition of harbour clubs and other interested parties. ESSC chipped in £2k to co-fund this project. This involved testing water samples and analysing chemical build-ups in seaweed, ragworms, limpets, crabs, oysters and shrimps at 22 sites in Chichester and Langstone harbours. This research was carried out by Professor Alex Ford from Portsmouth University and Professor Tom Miller from Brunel. A peer-reviewed report will be out later in the year, but the interim analysis was presented at ESC on July 12th.
What was found in the water?
50 chemicals were found: Pharmaceuticals such as antidepressants, painkillers, drugs for bladder infections, diabetes etc. and recreational drugs were found in the water samples. It was also found that these had accumulated in the marine life, with particularly high levels found in seaweed and ragworms. The team also discovered pesticides, including simazine, propamocarb, imidacloprid, and clothianidin which is a banned substance in the UK.
A base level of chemicals was established and compared to the levels immediately following a sewage storm discharge. Depending on the particular chemical, the level immediately after a storm discharge were often found to be 100 to 1000 times higher than the base level. This points the finger firmly at Southern Water's lack of capacity to cope whenever it rains. Following an untreated sewage discharge when it rained, ecoli levels were found to be 760 times the safe bathing limit in Langstone harbour and a massive 1800 times the safe limit at Thornham. The data was complicated, but in summary when the water is treated the ecoli and chemical levels are low, but when untreated sewage is discharged we have a real problem.
What can be done about it?
The problem is the wet weather capacity at the 4 main sewage works at Budds Farm, Thornham, Bosham and Chichester is insufficient to cope with the current levels of housing. It can be fixed, but initial costings are in the order of magnitude of £100 million, which is not something that Southern Water are going to undertake unless forced by the regulator. Unfortunately the grant for monitoring the water companies at the Environment Agency was cut from £120m in 2010 down to £40m in 2020. Recently however there are signs of change: Under new proposals, money from fines handed out to water companies that pollute our rivers and seas will be re-invested in schemes that benefit our natural environment.
So is the water safe to sail in?
The answer is that during most of the summer months when there hasn't been a heavy downpour the ecoli levels are within the EU bathing directive limits. However when there has been large amounts of rainfall it is worth looking at the Southern Water Beachbuoy site to see if there has been a major discharge (https://www.southernwater.co.uk/water-for-life/beachbuoy/) particularly at Budds Farm. This can make it under the bridge at Langstone and up into the Emsworth channel. Keep your mouth shut when you capsize.
What is the effect on wildlife?
In February 2021, Natural England's Condition Review Report downgraded Chichester Harbour Site of Special Scientific Interest (SSSI) to an "Unfavourable Declining" condition mainly due to the loss of saltmarsh and nesting sites. Chichester Harbour Conservancy are doing sterling work through the CHaPRoN project to try to reverse this.
The floating weed that forms in mats in May and June and gets wrapped around your centreboard is largely due to algal bloom caused by warm sea temperatures and excessive nitrates and phosphates, largely from farming run-offs. Often the scum on the surface and papery weed is mistaken for sewage. Nevertheless the untreated sewage discharges will certainly add nitrates that contribute to excessive weed growth in the harbour.
As for the long term effects of pollution from sewage discharges, there have been instances of oysters changing sex, crustaceans behaviour altering due to anti-depressants, but the real answer is we don't know and further research is needed.
Andrew Gould
Last updated 21:15 on 1 April 2024