One hundred and twenty five years ago, explorer Hugh Willoughby became the first non-Native American to cross the southern Everglades from the Gulf of Mexico to the Atlantic. He traveled with a guide by canoe, and kept notes on water quality in his journal.
In 2022, a group of adventurers, including University of Florida scientist Tracie Baker, canoed the very same extremely remote 130-mile path. Along the way, Baker took much more sophisticated water tests at 12 sites spanning the width of the Everglades, from the Harney River at the Gulf of Mexico, to the Miami River.
Her goal was to not only compare water in 2022 with 1897, but to assess the intrusion of modern chemicals into some of the most remote wilderness in America.
Though her final report is still in the works and has yet to be peer-reviewed, Baker recently revealed some surprising data in her preliminary assessment.
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Her water samples showed that human pollution such as pesticides, herbicides, microplastics and PFAS infiltrate most of the River of Grass, from areas close to Miami to areas 20 miles from the nearest human development.
When comparing her data to Willoughby’s, she found eight times as many solids in the water as he did. Those solids could be contaminants, salts or merely sediment — it’s a broad measurement that shows water now is very different than it was 125 years ago, she said. She also found higher levels of sulfate and nitrogen than Willoughby did. “That could be due to fertilizers, detergents, sewage and wastewater, which wouldn’t have been around at that time,” Baker said.
PFAS in paradise
Some of the more interesting preliminary findings are for chemicals that flow from civilization, many of which didn’t exist in 1897.
Baker was particularly interested in measuring PFAS, also known as per- and polyfluoroalkyl substances, which have been used since the 1940s to make human life easier. Baker tested both the water and sediment to find it.
“We saw PFAS at every site, and saw more in the sediment than in water.”
There are thousands of types of PFAS, and they’re used to “keep food from sticking to packaging or cookware, make clothes and carpets resistant to stains, and create firefighting foam that is more effective,” according to the National Institute of Environmental Health Sciences.
The problem is that they break down very slowly, if at all, and can build up in the blood of humans and other animals over time.
The Environmental Protection Agency said PFAS are used in cleaning products, non-stick cookware, paints, varnishes, and sealants as well as in certain shampoo, dental floss, and cosmetics. They end up in the environment and eventually in drinking water, fish, and in animals that graze on land fertilized with treated wastewater.“
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More research is needed to fully understand all sources of exposure, and if and how they may cause health problems,” says the NIEHS website.
To her surprise, she saw PFAS at some of the most pristine and hard-to-reach areas. She sampled for 90 types of PFAS and found 12 in the sediment and water.
Of the 12 sites she sampled, the farthest from civilization was Site 4, which sits in the sawgrass prairie just before the water there flows into the labyrinth of mangrove creeks that lead to the Gulf of Mexico.
As the crow flies, Site 4 is 24 roadless miles from Homestead, 23 miles from Tamiami Trail and 39 from Chokoloskee. In other words, it’s in the middle of nowhere.
“Site 4, which I would consider one of the most remote sites, had pretty high levels of PFAS in the sediment, and it also had high levels of pesticides,” she said.
The water there comes from both rain and Shark River Slough, a flow of water that moves south through Everglades and Francis S. Taylor Wildlife Management Area after trickling through the sugarcane fields south of Lake Okeechobee.
Microplastics and pharmaceuticals
Baker looked for microplastics, which come from beauty product microbeads, which President Obama made illegal in 2015, and from larger chunks of plastic breaking down into pieces smaller than 5 millimeters.
She found them across the entire width of the Everglades, and found higher densities closer to human development. Little is known about how microplastics affect the environment and human health.
Pharmaceuticals and other products also were on her list. She found synthetic sugars, pharmaceuticals, different medications and DEET in various combinations throughout.
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She also found glyphosate, the herbicide originally used in Roundup, at every site, and it was highest at Site 4, which was the most remote.
Though the EPA also found that glyphosate is “unlikely to be a human carcinogen,” in 2019, California courts sided with a school groundskeeper who claimed chronic exposure to glyphosate caused him to develop cancer and ordered Monsanto, who makes Roundup, to pay him $289 million. Studies have also shown it can damage fish liver functions.
As for antibiotic and antibiotic resistance genes, Baker found trimethoprim, used to treat urinary tract and ear infections, and amoxicillin. As she moved close to Miami, she found more antibiotic-resistant genes in the environment. The concern, she said, is that bacteria in the environment could develop a resistance to these drugs, and that bacteria could make its way into human populations.
Surprises, balloons and mangrove
The canoe trip across the River of Grass was arduous but beautiful — with blisters, cutting sawgrass and stunning sunset. But the data shows the human hand, even in the most wild areas.
“I assumed we’d find contaminants out in the Everglades because we know they’re ubiquitous in most places,” Baker said. “But I was most surprised by the amount we found in some of the more remote areas. Again, I thought Miami would likely have the highest levels, and it did for some of the contaminants, but not all of them.”
She was also shocked to find a Mylar balloon with the word “welcome” on it 20 miles from the nearest human settlement.
“Once we broke through the mangrove we were on the most remote part of our trip, and as we were canoeing along we came upon this one balloon, and then I started looking, and we found six balloons that day, just in that area.”
One of the most curious findings on the trip was the fact that the pollution at Site 3, just downstream from Site 4, had much less pollution.
“We did see a huge difference between the two — high levels (of contaminants) in Site 4 and almost nothing in Site 3 of most things.”
As to why, Baker had some thoughts that she has not tested yet. She said to reach Site 3, the water had to flow through a thick line of mangrove trees.
“So contaminants may be settling into the soil, as roots slow water down, or mangroves could be taking up the chemicals, therefore removing them.”She hopes her findings will prompt other scientists to investigate the path of the contaminants.
This story was produced in partnership with the Florida Climate Reporting Network, a multi-newsroom initiative founded by the Miami Herald, the South Florida Sun Sentinel, The Palm Beach Post, the Orlando Sentinel, WLRN Public Media and the Tampa Bay Times.
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