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City’s clean beaches claim: Results don’t add up

Half the 22 beaches the City claims have “excellent” water quality, are perennially polluted

As the summer holiday season approaches, the water quality at 22 of Cape Town’s most popular beaches and tidal pools is “excellent”, according to a statement released by the City on 24 November.

In the press statement issued by the City of Cape Town Media Office, the results of water samples at 22 beaches analysed over seven weeks from 3 October to 15 November are presented.

The results show the number of enterococci (a type of bacteria species found in human faeces which indicates other pathogens in the water) measured in colony forming units (cfu) per 100ml. The South African Water Quality Guidelines for Coastal Marine Waters state 95% of the tests must contain less than 185cfu/100ml for safe recreational water use. Each of the 22 beaches and tidal pools mentioned by the City had results well within the guideline for each of the weekly samples taken over the period. Sometimes the test results showed zero enterococci.

Normally, the City tests the water quality at 99 coastal monitoring points and recreational nodes along the Atlantic and False Bay coastline once every fortnight. The weekly sampling depicted in the 24 November press statement were independently analysed for a limited period and only along stretches of coast where beaches have been awarded Blue Flag status.

Eight Cape Town beaches have been awarded Blue Flag status this season, from 1 December to 31 January. The award is administered by the Wildlife and Environment Society of South Africa (Wessa) according to 33 criteria such as the provision of public toilets, accessibility for disabled people, and environmental programmes. Water quality, measured once a month during the period, is just one of these criteria for an award celebrated by the City as a tourism draw card.

Water quality results don’t add up

But the weekly water quality data presented in the press release does not tally with the fortnightly sampling results published by the City. Although the standard fortnightly testing results are not presented with the actual results and dates of the tests, but are amalgamated into a 365-day rolling average, they reveal that exactly half the 22 beaches touted by the City as clean, have “Poor” water quality. The indicator for “Poor” is an average of 90% of all samples containing an enterococci count of more than 185cfu/100ml or more than 500cfu/100m of E.coli, which is also an indicator species of faecal bacteria.

All of these 11 beaches and tidal pools have been labelled as having “Poor” water quality since at least 2022, with some of them, such as Seaforth beach in Simon’s Town, Monwabisi beach, and Strand’s “Pipe” surfing beach having “Poor” water quality since 2018, when the City began republishing its water quality results.

City officials, in previous correspondence with Mother City News, as well as at public meetings, have argued the 365-day rolling average is negatively affected by polluting storm water run-off in the rainy winter months, as well as by discrete pollution events such as short-lived sewage spills. The City has consistenly argued the coastal water quality is good over the summer months due to the lack of polluting stormwater run-off. However, the latest update of the average water quality results, termed the Water Quality Ratings, does show the latest available actual E.coli counts. In this case they are from the samples taken on 25 October. These create further confusion when compared to the enterococci results of 24 October, as published in the City’s press release. Ten of the 22 beaches depicted as having “excellent” water quality, had E.coli levels significantly above the allowed limit on 25 October, just a day after the City claims to have found very low – in some cases zero – enterococci.

E.coli and enterococci are both faecal bacteria indicating the presence of a host of other faecal bacteria and pathogens in the water, but the maximum limit for E.coli is 500cfu/100ml as opposed to the maximum of 185/100ml for enterococci. While the City claims Camps Bay tidal pool had less than 150cfu/100ml of enterococci on 24 October, the City’s Water Quality Ratings state the E.coli count in the tidal pool was 7,260cfu/100ml on 25 October.

Similarly, the press release states there were zero enterococci in the sample taken on 24 October at what it states is Cape Town’s “most visited beachfront” – surfer’s corner at Muizenberg. But the E.coli count a day later, on 25 October, was 921cfu/100ml.

This pattern is repeated at Seaforth beach and Long Beach in Simon’s Town, Dalebrook tidal pool in Kalk Bay, St. James tidal pool, Strandfontein beach, Strandfontein tidal pool, Monwabisi tidal pool, Monwabisi beach, and Strand.

Camps Bay tidal pool, Simon’s Town’s Long Beach, Monwabisi tidal pool, and Strand “pipe” surfing beach all had E.coli counts of 7,260cfu/100ml, which appears to the maximum measured by the City.

Independent view

Epidemiologist and University of Stellenbosch Professor Emeritus Jo Barnes said the significant difference between enterococci and E.coli results at ten beaches and tidal pools over 24 hours “sets off an alarm”.

Barnes said if the water was contaminated it would be expected that enterococci and E.coli levels would both be high, although theoretically, in salt water, one indicator may be lower than the other. She said there also may be other chemicals in the water, such as pharmaceutical compounds and chemicals from household and hygiene products contained in sewage, that could potentially “knock out” the enterococci and not the E.coli, which meant a low enterococci count did not necessarily indicate the water was clean. This was why tests were normally run for both indicators.

She said it was theoretically possible that the water was clean on 24 October and there was a sewage leak overnight, causing the contamination found on 25 October, but it was “highly unlikely” that would happen in all ten places, ranging from Camps Bay to Monwabisi. Even if there had been rainfall overnight resulting in pollution running into the sea from the stormwater system, run-off of that magnitude would have affected all 22 beaches listed as having “excellent” water quality. (Historical weather data shows there was no rainfall in Cape Town on 24 or 25 October.)

With 17 recreational coastal nodes on False Bay and 12 on the Atlantic coast that were “permanently in the red (poor water quality)”, she said it seemed the City was “cherry picking” the results that suited them.

Additionally, she said it was “highly unlikely” to get zero enterococci results, as found numerous times according to the City’s press release. Beyond faeces from marine mammals, there are three marine outfalls pumping millions of litres of raw sewage into the sea on the Atlantic coast, and “a massive amount” of partially treated sewage effluent flowing into the sea from sewage treatment works on the False Bay coast. “That makes repeated zero readings of either micro-organism highly unlikely. When you get something so unexpected, you check up and see that it is true.”

City response

Deputy mayor and City mayco member for spatial planing and environment, Eddie Andrews, said in 2021 the World Health Organisation removed E.coli as a meaningful indicator of marine water quality. Andrews said the reason the City started “an independent 12 month weekly sampling regime at 30 key locations is that for the last nine months due to procurement related issues the City’s scientific services has only been able to provide E.coli data for coastal water quality”.

He said this was “far from ideal”, and the City only used E.coli as a broad indicator of sewage pollution when no enterococci data was available. He said it was stated on the City’s water quality web page that the inability to measure enterococci had “impacted on our ability to calculate water quality categories”.

Regarding disparities between enterococci results of 24 October and E.coli results of 25 October at Muizenberg, Andrews said the enterococci measurements contained in the press release were taken at Muizenberg central, in front of the ablution block where most people surf. He said there are five locations in Muizenberg where the city does its standard fortnightly testing, and all provided different results depending how far they were from the stormwater outlet or the Zandvlei estuary mouth. Andrews then provided enterococci results from August 2018 until the last date the City Scientific Services were able to measure enterococci levels, being 5 April 2023. Only 11 of the 110 tests over this period showed enterococci levels exceeding the maximum allowed levels. But these were from the Muizenberg Pavilion area, which is further from the stormwater outlet than Muizenberg central, where the samples were taken for the independent enterococci tests.

Regarding disparities between good and excellent enterococci results on 24 October, and failing E.coli results on 25 October at Camps Bay tidal pool, Simon’s Town Long Beach, St. James tidal pool, and Dalebrook tidal pool, he said enterococci and E.coli data were not interchangeable.

Regarding certain beaches being celebrated as having excellent water quality yet classified as having “Poor” water quality over a 365 day rolling average, he said the City’s press statement was clear that the results were based on independent analysis over seven weeks up until 15 November.

“This is in fact goods news as Cape Town depends on tourism for its economic growth and which sustains and supports many jobs and one would hope that broadly these results and this announcement would be welcomed and supported.”

He also supplied enterococci data for Camps Bay tidal pool from November 2016 to November 2021, noting only eight of the 122 results showed unacceptable enterococci levels over the five year period. These isolated cases were caused by overflows or plumbing leakages from the adjacent sewage pump station outlet at the ablution block.

Seaforth Beach, Simon’s Town Long Beach, Strandfontein Tidal Pool, Monwabisi Beach, and Strand Beach had “similar explanations”, he said.

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