Tributaries Big Source of River Pollution
However creeks, ditches not part of cleanup plans
By Suzanne Wentley Ft. Pierce Tribune staff writer
December 13, 2002
After a year of monitoring, state scientists on Thursday said 27 of the 38
urban creeks and ditches tested in Martin and St. Lucie counties directly
pollute the St. Lucie River and the southern Indian River Lagoon with high
amounts of nutrients and metals.
The biweekly testing started in November 2001 to determine the quality of the
water in the tributaries that account for 30 percent of the runoff into the
river.
The tributaries are not part of the $1 billion local Everglades cleanup plan, unlike the irrigation canals
in St. Lucie County and the St. Lucie Canal in Martin County. Those waterways make up the remaining 70
percent of the flow into the river and lagoon, according to South Florida Water
Management District reports.
However, Boyd Gunsalus and Al Goldstein, senior environmental scientists with
the district, said the high amounts of phosphorous, ammonia, nitrites and
nitrates, copper and arsenic in the area's small water bodies are cause for
concern.
"You need to understand the problem before you can build a solution,"
Goldstein said.
"The source of the problem comes off the land," he said. "There
are a lot of assumptions, that it's all citrus land, but urban is to blame
too."
Goldstein and Gunsalus created an almost comprehensive list of tributaries into
the local waterways, without the main irrigation canals, and contracted out the
work of sampling the water for nutrients, metals and physical characteristics
such as temperature, levels of dissolved oxygen and turbidity.
Most of the creeks and ditches exceeded the levels the scientists set for
phosphorous, ammonia, nitrites plus nitrates and copper.
Phosphorous and nitrites plus nitrates -- all nutrients -- can cause algae
blooms, fish kills and water clarity problems in the estuary. Ammonia and
copper can be toxic to marine life.
The scientists have not yet analyzed the data to determine the direct cause of
the pollutants, but Gunsalus said there are some likely sources:
Phosphorous and nitrates are often products of too much fertilizer use.
Copper could be a result of copper sulfate, an inexpensive herbicide and
fungicide.
Arsenic, like the others, occurs naturally, but a high presence could be left
over from old cattle-dipping vats.
Ammonia can leach into groundwater from leaking septic tanks then make its way
into the waterways.
Even though state officials have yet to set maximum amounts of the nutrients
and metals the river can tolerate, the scientists said they created "red
flag" levels at which problems can arise.
Phosphorous levels should not exceed 150 parts per billion, but 15 sites did.
Ammonia should not exceed 100 parts per billion, but 11 did. Nitrite plus
nitrates should not exceed 100 parts per billion, but 14 did.
The state Department of Environmental Protection set levels for copper: 2.9
parts per billion as a maximum for saltwater, depending on how hard the water
is, and 30 parts per billion maximum for freshwater.
Because the St. Lucie Estuary is brackish -- a mix of salt and fresh water --
state scientists set the "red flag" at 6 parts per billion, and 10
sites exceeded that limit.
Gunsalus said arsenic levels were also tested. Most sites were in the healthy
range, under two parts per billion, except one tributary, Piper's Ditch, which
at 5.94 parts per billion was well beyond state standards.
Engineers and educators with the St. Lucie River Initiative and the Florida
Yards and Neighborhoods program said the testing can help them pick the hot
spots that need the most attention.
"That's the key to it all," said Edie Gastright, the program
assistant with Florida Yards and Neighborhoods, an educational element of the
water quality improvement program administered by the agricultural extension
offices.
"If you don't know where it's coming from, you don't know how to correct
it," she said.
Gastright said one tributary -- the Hidden River in Port St. Lucie -- will be the subject
of an educational meeting on how homeowners around the waterway can stop
pollution on their property. The meeting is scheduled for 7 p.m. Monday at the Port St. Lucie Community
Center.
Although the monitoring program didn't test the quantity of water flowing in
the river and lagoon, Gunsalus said he planned to add six water level stage
recorders throughout the area.
Already, the water quality monitoring program costs about $160,000 a year.
Water stage monitors cost about $20,000, Goldstein said.
But state scientists said it's worth it. During the next three years of the
program, they will be able to gauge the effectiveness of stormwater
improvements in older neighborhoods in Martin and St. Lucie counties.
"I've got a little data at Frazier Creek," Gunsalus said, referring to an
early Stuart stormwater improvement project. "And it's promising."
They will also be able to examine the effectiveness of the voluntary
environmental improvements at area's farms and groves, he said.
Joining all the improvement projects -- and backing them up with scientific
data -- will help clean up the St. Lucie River and the Indian River Lagoon that
much faster, Goldstein said.
"They're doing things and they're doing things. Let's put it all
together," he said.
- suzanne.wentley@scripps.com
Back to Articles