Every once in a while we will write an article related to the quality of water used for swimming that has absolutely nothing to do with water in swimming pools… and today we would like to touch briefly on the topic of beach closings due to elevated bacteria levels found at beaches.
Ever pack up the family and head to the beach only to find that officials had closed it (posted signs prohibiting swimming) due to routine test for bacteria coming back higher than health regulations permitted? Did you then wonder why the beach closed a day AFTER testing took place? If so, then you have had the same thoughts as folks Evanston, Illinois who monitor water quality conditions on several beaches on Lake Michigan.
Current testing methods take too long
At this time it takes between 18 and 24 hours for laboratory test results to get back to beach officials. This means swimmers on a Tuesday, for example, could swim in potentially unsafe water and beach officials would not know to close the beach until Wednesday… and the conditions which caused the beach to get closed (a day later) may already have improved.
Proposed idea for improvement
As you just saw, the current testing methods take too long, put swimmers at risk, and potentially keep other swimmers, for no good reason, from enjoying the water. Health officials in Evanston, Illinois came up with an idea that could help to make diagnosis of beach water quality more of a real-time process.
While the final word on water safety will still come from the laboratory, beach personnel will look at factors like air & water temperature, recent rainfall, wind direction, and other factors which they believe may contribute to the buildup of potentially harmful bacteria in the water. The results of those observations will get charted against the lab results to see if some sort of ‘predictable’ relationship exists.
This sort of prediction has worked relatively well for other beaches and Evanston officials hope they will share in that success.
For the past five years, the city has used an EPA sanitary beach survey, which focuses on environmental factors that can cause a beach closure, Caneva said.
Those conditions include such factors as rainfall, air temperature, water temperature, turbidity, number of swimmers and nonswimmers on the beach, pollution sources, items floating in the water, the presence of birds and algae.
With the new system, health officials will assign a value to the data collected for each of those environmental factors. By plugging those values into an equation, Caneva said the city hopes to be able to better predict when the factors are right for a beach closure.
The city will continue testing water daily and will compare the accuracy of the prediction model to test results.
“This makes so much more sense, rather than everyone wondering why we’re closing a beach the day after conditions existed that require the beach closure,” said Ald. Jane Grover, 7th, during a recent Human Services Committee meeting. “I’m curious to see whether the scientific data matches up with the statistical predictions.”
The predictive model is used elsewhere, including at some beaches in Lake County, Caneva said. He said Lake County reports an 85 percent accuracy rate in predicting beach closures.
The city’s six beaches were closed 23 times last year, down from 48 times in 2010.
Caneva said the relatively low rainfall totals last summer probably played a large factor in that drop in closures from 2010. ( source )
So… what about the rest of us NOT going to the beach and stuck at home enjoying a dip in a public or private pool? We need to make sure the water has the proper amount of sanitizer (usually chlorine or bromine) and that critical water quality parameters such as pH, total alkalinity, stabilizer (cyanuric acid), and total hardness all have the correct levels before hopping in to cool off.
To know fur sure that all levels measure correctly at any given time homeowners and operators of private swimming pools need to test the quality of their pool water on a regular basis using a traditional wet test kit such as the Poolmaster 5-Way Test Kit, Pool Check Test Strips, or the eXact Micro 7+ Pool Water Testing Meter.
