‘Swim­mers at risk on pol­luted city beaches’

Weekend Argus (Saturday Edition) - - FRONT PAGE - KOWTHAR SOLOMONS

SWIM­MERS us­ing pol­luted Cape Town beaches faced sig­nif­i­cant health risks, a top sci­en­tist has warned.

The City of Cape Town had un­der­es­ti­mated the risks posed by pol­luted seawa­ter on the At­lantic and False Bay coast­lines, epi­demi­ol­o­gist Dr Jo Barnes cau­tioned.

A re­port by the city on the state of beaches and bathing spots over the 12 months which ended in June iden­ti­fied sev­eral places which failed to com­ply with health and safety reg­u­la­tions “by a very small mar­gin” but were gen­er­ally deemed still safe for swim­ming this sum­mer.

Sam­ples in­di­cated pol­lu­tion con­tam­i­na­tion along the False Bay coast­line at Muizen­berg, near the train sta­tion, and six spots from Ma­cas­sar to Strand.

Sites that were not up to scratch on the At­lantic Se­aboard were Melk­bosstrand, Blou­berg Big Bay, Three An­chor Bay, Rock­lands, Saun­ders Rock and The Kom, op­po­site Har­mony Park.

Brett Her­ron, may­oral com­mit­tee mem­ber for trans­port, said the mar­gin of non-com­pli­ance was very small and the beaches were safe for swim- ming, un­less oth­er­wise in­di­cated by the city’s health depart­ment.

How­ever, Barnes be­lieves the data is dif­fi­cult to in­ter­pret as it has been “smoothed” to pre­sent av­er­ages. This might paint a more rosy pic­ture than mer­ited and the find­ings should be han­dled with cau­tion.

“These sites did not com­ply by a very small mar­gin, which in­di­cates the pol­lu­tion lev­els were rel­a­tively low. Sites that are chron­i­cally non­com­pli­ant, and which ex­ceed the guide­lines by a sig­nif­i­cant mar­gin, are prob­a­bly af­fected by se­vere pol­lu­tion which may be on­go­ing and would, there­fore, be more risky,” Her­ron said.

“Some sites, how­ever, may fail guide­lines by a small mar­gin and this could be due to spo­radic low lev­els of pol­lu­tion.

“As such, these sites have a lower risk level.

“The health depart­ment as­sesses these fig­ures and will is­sue an ad­vi­sory and or erect ap­pro­pri­ate sig­nage at con­tam­i­nated sites.

“With re­gard to swim­ming at the beaches, it would only be ad­vis­able to avoid swim­ming if these signs are dis­played,” he said.

“Typ­i­cally, the amount of pol­lu­tion is mea­sured by how much e coli ( Escherichia coli) bac­te­ria are pre­sent in ev­ery 100ml of wa­ter. How­ever, the re­port does not in­di­cate which or­gan­ism is used in which ta­bles.

“When the city in­di­cates that an area is non-com­pli­ant, it sim­ply states that it is over the limit but not by how much. In re­al­ity, the higher the level, the greater the health risk. Not re­port­ing on peak pol­lu­tion pe­ri­ods makes it dif­fi­cult to in­ter­pret the real health risks.”

“The pol­lu­tion data are of­ten av­er­aged or ‘smoothed’, thereby re­mov­ing the peak data val­ues. The health risks are par­tic­u­larly high at peak val­ues, which are not listed.

“Some of these sites are mon­i­tored only a few times a year. That means that there are large pe­ri­ods for some of the sites that there is no knowl­edge of the peaks in pol­lu­tion lev­els that may have oc­curred un­no­ticed or un­de­tected,” Barnes said.

Pro­fes­sor Tally Palmer, direc­tor of the Unilever Cen­tre of Wa­ter Qual­ity In­sti­tute for Wa­ter Re­search at Rhodes Univer­sity, agreed that some as­pects high­lighted by the city’s re­port needed to be tack­led, no­tably those linked to spills from waste wa­ter treat­ment works (WWTW).

“The re­port states that there are 110 pump sta­tion and ris­ing sewage over­flow in­ci­dents over the time pe­riod of the re­port. This re­port may not have staffing im­pli­ca­tions for the city but it sure does for WWTWs.

“This needs to be high­lighted as there is a de­pen­dency on bet­ter WWTW func­tion with suc­cess. The is­sue of il­le­gal dump­ing should also be ad­dressed,” Palmer said.

Ac­cord­ing to the re­port, the re­cently com­pleted up­grade at the Phoenix pump sta­tion would help deal with over­flow.

Ear­lier this month, the col­lapse of a ma­jor pipe caused a sewage spill into Mil­ner­ton La­goon. A high e coli con­cen­tra­tion led to the pub­lic be­ing warned to stay out of the wa­ter.

The sewage spill is re­port­edly be­ing treated with a mix­ture of en­zymes and sev­eral bac­te­ria.

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