US environmental beach study erred
The group that issued a report last month on America’s dirtiest beaches said it found errors in its methodology and calculations.
The environmental research group that issued a report last month on America’s dirtiest beaches said it found errors in its methodology and calculations. The result: fewer beaches had problem bacteria levels last year than the group had previously said.
The biggest changes involve beaches in Great Lakes states, according to the revision released earlier this month by the Environment America Research and Policy Center. The study focused on beaches with the most days of potentially unsafe levels of bacteria primarily linked to fecal matter.
The organization said the changes should not diminish the study’s overall importance.
“The report still has great value – and a big regret is the errors distracted from the overall message of the importance of protecting our water,” said John Rumpler, clean water program director for Environment America.
The study received widespread attention when it was released July 23. When the errors were discovered, Environment America removed the report from its website and started reviewing its methodology. The new version was posted Aug. 2.
Under the new calculations, 2,580 of 4,523 beach sites tested nationwide, or 57%, were found to have water pollution levels at least one day in 2018 that exceeded the strictest safety guidelines from the Environmental Protection Agency. That’s down from 2,627 beach sites in the earlier, uncorrected report.
Of those, 546 were found to be unsafe on at least a quarter of the days they were tested, down from 610 in the initial report. The study is based on data collected from beaches in 29 Great Lakes and coastal states and Puerto Rico.
Environment America said its research arm, Frontier Group, made two fundamental errors in its analysis of water data submitted to the federal government. One was not taking into account that agencies use different measurement methods for water sampling. The other was a calculation error involving the benchmark number for E. coli, one of the bacteria found in human or animal feces.
The fundamental point of the study: Many beaches often become unsafe at some point during a year, usually from waste from storm runoff and sewage overflows, Rumpler said. If those flows can be reduced, beaches stay cleaner on more days of the year.
“Our overall intention is to alert the public that our beaches are not as safe as they might assume, not as safe as they should be or not as safe as they can be,” Rumpler said.
The study was revised after authorities in some of the counties covered by the report raised questions about its veracity. The study was reported in USA TODAY and by other news organizations around the country.
Chicago Park District, for instance, which had been singled out as having problems at 19 beaches, said it believed the initial results were wrong due to its choice of testing methods.
Environment America agreed and changed its findings. But the district said in a statement it is still “disappointed by the continued use of incorrect or skewed data that provides misleading information to the public.”