The biological mystery started two years ago with an anonymous tip: A couple of children had come home ill after playing in the sandbox at a public park in Redwood City, Calif.
Christopher Beth, director of the Parks, Recreation and Community Services department, decided he shouldn’t take any chances. So he ordered that the sand be tested — a first for the city on San Francisco Bay’s Peninsula. “Other cities say they don’t test either,” Beth said. “There’s no requirement.”
It was a good thing he did. The results showed high levels of E. coli bacteria. Since then, a similar problem was discovered at another city park. The sand play areas at both parks are being replaced with water features, officials said, and the renovations should be done by mid-January.
“Obviously, when we first found out about it, we were shocked like everyone else,” said Shawn White, a member of the Redwood City Parks, Recreation and Community Services Commission. “Even more surprising to us was that the state and county don’t really have a standard on what are acceptable levels of E. coli in playgrounds. Even a little bit was unacceptable to us.”
Children have been playing in sandboxes for generations, and public health experts say there’s a reason why state and local officials don’t regularly test the sand: cases such as the two in Redwood City are exceedingly rare. “The California Department of Public Health is not familiar with any research studies related to E. coli in sandboxes,” said Ron Owens, a public information officer with the agency.
Representatives of the New York State Health Department, the Florida Department of Health and the U.S. Centers for Disease Control were also unaware of cases of E. coli linked back to sandboxes.
Carina Blackmore, Florida’s state public health veterinarian, said E. coli is a family of bacteria that we have all around us, and most types don’t cause disease. “There are a few of them that produce toxins that have been responsible for the outbreaks we have seen,” she said. “I’m not surprised that we would find it in sand, though, because the bacteria survives very well in that environment.”
However, Blackmore added, it would be rare for harmful forms of E. coli to be found in sandboxes. Those types come primarily from cattle and other ruminants. “Sandboxes are not … riskier than other environments,” she said.
Katherine Karlsrud, a pediatrician with a private practice in New York City, said she had never heard of kids getting E. coli from a sandbox before. Still, she recommends caution. “If the kids are still at the age where they’re putting their hands in their mouths, probably keep them away from the sandbox,” she said. “If they’re old enough not to put their hands in their mouth, then just wash them thoroughly afterward.”
Once the Redwood City parks department discovered the high levels of the bacteria, Beth immediately brought in a company to clean up the sand at Stafford Park. “It was like the movie Outbreak,” he recalled. “They put plastic everywhere and were in space suits, and we were like, ‘Oh my god!’ So we stood out there and let people know what was going on. We didn’t want to freak people out.”
After the contaminated sand was replaced, Beth continued to test for bacteria; soon, there were high levels of E. coli present again. Nothing the city tried seemed to work — including turning off a nearby water feature, bleaching the sand, redoing the drainage system and changing the type of sand used.
The sand features at all the other Redwood City parks were tested, and just Maddux Park came up with an additional E. coli problem. The source of contamination was feline feces in one case and human feces in the other.
“We spent about $70,000 trying to mitigate this thing, but we couldn’t keep up,” Beth said. “We had to come up with a long-term solution.”
The Parks, Recreation and Community Services Commission was adamant about including the community in discussions about what would replace the sand features at Stafford and Maddux, White said. According to Beth, community members liked the water features at the parks, so Stafford will have a “snail stream” and Maddux will get a trio of “spitting frogs.”
The new features will not use recycled water and are unlikely to harbor any harmful bacteria, according to Beth. “These are low flow actuators, so they go into a drain,” he said. “We’ve actually looked at putting in filtration and recycling systems… chlorinating, but with staff maintenance and everything else it’s off the charts in terms of expense.”
Initially, some residents were saddened about losing the sand features they fondly remembered from their childhoods. But they appear to be warming to the planned modifications. “I think it’s a great idea that they’re changing it,” said Leslie Parker, a mother who often brings her toddler to Stafford Park. “It’s nice to know they were testing it in the first place.”
Redwood City residents who still want access to sand features can go to any of five other parks, which are being tested on a monthly or quarterly basis.
However, Beth said, “In future park renovations, we’re definitively looking to stay away from sand.”