NEA Monitoring E. coli at Sentosa After Raised Levels Delay Swim Events

It usually measures levels of Enterococcus, another group of bacteria, based on WHO guidelines

- Chin Hui Shan

The National Environment Agency (NEA) has started monitoring levels of Escherichia coli (E. coli) at Sentosa's beaches, after swimming events at the World Aquatics Championships were twice delayed due to elevated levels of the bacteria in the waters.

NEA does not usually assess marine water quality based on E. coli levels. Instead, it follows World Health Organisation (WHO) guidelines to determine the suitability of a recreational beach for primary contact activities, by measuring the levels of another group of bacteria, Enterococcus.

In response to queries from The Straits Times, NEA said that WHO recommends using only Enterococcus for assessing marine water quality. Epidemiological studies have shown a strong correlation between Enterococcus levels in marine waters and public health risks.

WHO has assessed that there is currently insufficient data to develop similar guidelines for E. coli - a suitable faecal indicator for freshwater - for marine waters, NEA added.

"While NEA will continue monitoring our beach water quality based on Enterococcus, we are currently also monitoring E. coli levels at the Sentosa beaches arising from this latest development," said NEA.

It added that the E. coli levels on July 15 were low and that the agency will continue to monitor the water quality at the Sentosa beaches over the next few days.

NEA said its weekly water monitoring showed that water quality at the beaches has been in the "normal" range in the past few weeks.

The recreational beaches are also graded every six months based on the past 100 samples. NEA said the Sentosa beaches were graded "good" in the latest grading exercise in January, and were suitable for swimming and other primary contact activities.