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New study questions safety of chemical used to kill mosquitoes

Posted at 7:41 PM, Jun 08, 2017
and last updated 2017-06-08 19:41:43-04

The Zika virus scare of 2016 was real. Testing revealed hundreds of women carried the virus.

And with heavy rain this week, more standing water means more breeding grounds for the mosquitoes that carrying viruses like Zika.

"We have 16 traps around the county, they go out twice a week so when those numbers are really elevated, we know it's time to do something about it," said Chris Reisinger, an environmental analyst for Palm Beach County Mosquito Control.

That's why Mosquito Control is planning aerial spraying next week.

But new questions being raised today on the chemical used in aerial spraying to kill the bugs. A new study released on Thursday by the University of Michigan is warning of the dangers pesticides like naled can cause in babies. Naled is used in Florida and across the U.S. in aerial sprayings.

Click here to read the study's findings.

"We were really interested in the environmental exposures in China anyway. They're one of the world's largest users of pesticides," said Monica Silver, the lead author on the study. "There's widespread exposure to these chemicals and they maybe aren't as well studied as they should be."

In a phone interview, Silver told WPTV that her team studied cord blood from 237 mothers who gave birth to healthy babies in hospitals in Southeast China and found deficits in motor functions of those infants as they grew older. The births occurred between 2008 and 2011. At six weeks, the babies were healthy but when they reached nine months, babies had problems with coordination, movement and other developmental skills.

The team found other pesticides in the infants like chlorpyrifos, which is used on vegetables, fruit and other crops to control pests.

"I was surprised after I found the results of naled and I went and looked at literature, at just how little information there is about it. It really hasn't been studied in human populations before," she said.

The authors of the study said they wanted to examine real-world exposures to naled outside of accidents in the workplace or lab experiments.

"That's very different than low-level real life, everyday exposures that people might be being affected by," said Silver.

It's unknown how naled and other pesticides were being used in the area of China the infants were studied, but it's the same chemical approved by the EPA and U.S. Department of Agriculture.

It has been approved for use in the U.S. for the last 50 years. Palm Beach County assures that it's safe.

"I've got more faith in our government than I do in the Chinese government, in terms of pesticide regulations," said Reisinger.

The chemical sparked protests last year when Miami sprayed naled by plane in Zika hot zones.

"A lot of the controversy in Miami came from spraying it in the middle of the day," said Reisinger. "The hot ground with updrafts, it's really hard to get your droplet size all the way down to the ground if you're spraying during the day. You're basically keeping your chemical up in the air."

Palm Beach County uses naled in aerial sprayings about 4 to 6 times a year at night and in smaller concentrations. They use about a thimble full per acre of land in the county.

"We're using it very sparingly," said Reisinger. "We don't do aerial spraying very often. That's sort of last resort."

Reiginger also said the chemical evaporate shortly after spraying.

"We can't even find it in the morning. If we're out there trying to test for naled in the environment, we can't even find it two hours after it's been sprayed," he said. "We spray just enough to kill mosquitoes."

We tried reaching out to Amvac, the manufacturer of the naled pesticide, for comment but have not heard back. A spokesman told the Miami Herald they had no record of selling naled in China and were puzzled by the findings.

Mosquito Control said that the company had to submit research proving it's a safe pesticide for use in order to be cleared by the U.S. government.

Reisinger added that Palm Beach County also focuses more on killing larvae.

"It's much easier to target them when they're in the water. We use a chemical called BTI, which is a naturally occurring bacteria," he said.

Silver told me the study is not meant to create panic but awareness.

"I think it's still too soon to tell since this is the first study. But it's always a concern when you have to spray a chemical and potentially vulnerable populations are being exposed," she said. "I just really think more work needs to be done concerning naled and many other pesticides that are used."

Mosquito control told me over the decades they've used it, they haven't gotten any complaints on naled.

If you're worried about Zika, Mosquito Control wants you to exercise other methods to get rid of mosquitoes, starting with trash.

"Open coffee cups, junk left around people's yards, buckets, plant saucers, things of that nature -- always tip and toss your water," he said.

You also want to apply mosquito repellent and wear long-sleeves and pants before going outside at dawn or dusk.

Mosquito control also uses a different type of pesticide for hand sprayers and trucks, one that that's widely available at hardware stores.

Mosquito control sprays depending on complaints or trap samples, but usually starts in the worst parts of the county for mosquitoes like The Acreage, Loxahatchee and Jupiter Farms.