Murky History

 

Murky History

 

Date: March 28, 2013
by: Roger Drouin | City Editor

 
 

The waterway at the heart of one of Sarasota’s most affluent neighborhoods looks exactly like how a million-dollar view should look — scenic and serene.

But Hudson Bayou, the body of water where 1,700 acres of downtown stormwater runoff drains, has a murky history. The bayou, which is currently classified as an imperiled waterway, has been tainted with trash and nutrients, which scientists who study red tide, such as Dr. Bruce Neill, president of the Sanibel chapter of START, have recently linked to red-tide blooms.

In January, the latest in a series of sewage spills plagued the bayou, and thousands of gallons of raw sewage leaked from Lift Station 7 into the water. Algal blooms have created a thick tainted muck on the bayour floor. Even a fuel spill at the county jail a mile away in 2000 killed some of the mangrove leaves that line the bayou.

But, a toxic metal as shallow as 4 inches underneath the surface of the bayou floor is the most mysterious and troubling form of pollution for some residents and area environmental scientists. Levels of lead above the state threshold for human contact were first detected in 1992 and are said to be encapsulated below the bayou’s sediment floor.

“Hudson Bayou suffers the indignities of many years of urban runoff,” said Rob Patten, a former Sarasota county ecologist who has lived in the Hudson Bayou neighborhood for 36 years. “And it all goes into Sarasota Bay.”

Sediment testing the Sarasota Bay Estuary Program funded and Mote Marine Laboratory conducted in 1992 found levels of the toxic metal that were “very high” compared to national levels found in waterways.

But, at the time, not enough data was available to determine if the lead was harmful to fish, shrimp or humans who might swim in the water. Subsequent testing in 2001 revealed that more than half of the sediment samples exceeded the levels for “Marine Sediments Probable Effect Limit” — or the threshold above which adverse effects are expected to occur frequently in the marine ecosystem.

“We don’t swim, don’t walk on the bottom, don’t fish those waters,” said Susan Chapman, a longtime Hudson Bayou resident. “It’s a continuing concern for those of us who know about it.”

A multimillion-dollar project to dredge some of the lead from the bayou’s sandy bottom is stalled due to a lack of funding.

After the 2001 study, county biologists concluded the lead was not increasing and, in some cases, was getting buried deeper under the floor of the bayou, said Theresa Connor, a former stormwater planning supervisor with Sarasota County.

Residents have been told the lead isn’t in the water.

“They told us it shouldn’t be disturbed,” Chapman said, “that it is stable.”

No smoking gun
These days, residents wonder what future effect, if any, the lead has on those who kayak, swim or fish the bayou.

“We don’t know the public-health implications,” Chapman said. “It has not been defined. It has been minimized.”

Although the exact impact on health has not been determined, another murkier, unsolved mystery remains how the lead got into the bayou.

The Hudson Bayou sediment samples tested in 1992 stood out for their “very high” lead levels, said Kellie Dixon, a scientist at Mote Marine Laboratory who collected and tested the samples.

Specifically, the amount of lead in four locations of the bayou were higher than any other waterway in the city, including nearby Whitaker Bayou, which also receives stormwater runoff from the downtown drainage basin.

“It was high in comparison to a national dataset,” said Dixon said.

It has, however, proven difficult to pinpoint the source of the lead discharge. John Ryan, environmental supervisor at Sarasota County, spearheaded an effort in the 1990s to try to do so.

“At one time, I was burning to find that (information),” Ryan said.

Finding a possible source of the lead pollution would mean local governments could seek financial help from an industry or company to fund a cleanup project.

“We went in every pipe, trying to find a responsible party,” Ryan said. “The evidence was not there to say it came from one tributary or one source.”

Hudson Bayou residents and area scientists have heard a wide range of what Chapman calls “common street-knowledge” hunches.

One possible source included the old Herald-Tribune printing press on Orange Avenue in Burns Square that bordered a canal flowing into the bayou. At the time, linotype printing machines used lead as a component. The newspaper was located on Orange Avenue from 1925 until the mid-1950s, said Jeff LaHurd, historian at Sarasota County History Center. An old machine shop. — where acetone and lead were used during the process to rebuild engines — is another possible contributor that has been discussed.

“In the old days there were not a lot of regulations,” Patten said.

Lead runoff from lead-based fuel and chipped lead-based paint that was formerly used on boats are other possibilities, Patten said.

No one source, however, has ever been pinpointed.

“There wasn’t any clear smoking gun,” Dixon said.

Encapsulated
The 2001 study showed the high levels of lead persisted.

Lead was found at an average depth of 2 feet below the bottom of the bayou.

“In general, the presence of lead in the bayou is much more prominent than originally implied,” the 2001 study concluded.

The highest concentrations of lead were three times above the state standard set for human exposure to lead in the ground; however, the samples taken in Luke Wood Park, a park near the bayou in the Hudson Bayou neighborhood, were below the state threshold.

A sliver of good news was that the highest quantities of lead were well below the surface, and the amount of the toxic metal did not seem to be increasing over time, Connor said.

“There is no indication that there is ongoing lead discharge,” Connor said in an interview with the Sarasota Observer March 25.

Because lead doesn’t go away, the most accurate way of looking at the results from 2001 was to say the environment was encapsulating the lead, Connor said. And no lead was found in the water, itself.

The lead also seemed to be contained to the bayou.

“It’s not like we have an industry pumping pollutants out like in an urban place or a place with big industrial (uses),” Ryan said.

But questions remain.

For Patten, one big unknown is what will happen if the lead is left under the bayou.

“There is no way lead is a good thing,” Patten said. “But is that lead being re-suspended?”

In 2001, even as the bayou showed signs the lead wasn’t increasing, scientists were worried about the impact of the toxic metal on oysters and critters such as shrimp that live in the benthic community where water and murky bottom meet, Connor said.

What would it take?
Ridding the bayou of the lead could cost anywhere from $6 million to upward of $10 million. Ryan said he thinks a cleanup would be a worthwhile improvement.

“It’s a good candidate for a cleanup,” said David Shafer, an environmental consultant and co-director of the Science and Environmental Council (SEC) of Sarasota County. “We’re trying to raise some social and political capital to get that project put onto a priority list,” Shafer said.

One option is to secure funding through the BP oil spill RESTORE Act. That is a long shot, because so many projects are in line for funding through a potential settlement paid as a result of the BP Deepwater Horizon Gulf oil spill.

The 2002 study estimated 62,000 cubic yards of sediment would have to be dredged from the bayou to remove the lead.

Further testing would be needed before such a project was undertaken to make sure the greatest amount of toxins are removed.

In the meantime, the county and city have been working on improving bayou water quality.

A $1.4 million county project is slated to filter the polluted runoff that flows into the bayou. A contractor was chosen last month for the project that could take nine months to complete once started. The project would filter nutrients and other pollutants in rainwater runfoff. The city has also been working on a $12.5 million lift station project.

As part of that project, a new lift station is being built in Luke Wood Park to replace a lift station at 935 Pomelo Ave.

The Pomelo lift station is aging and has a history of malfunctions and sewer spills, including a 570,000-gallon spill seven years ago into Hudson Bayou.

 

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