The Miami Herald

Posted on Fri, Mar. 17, 2006

ENVIRONMENT

Tests indicate risk to Dade's drinking water

New studies increased worries that a key Miami-Dade water source may be at risk of contamination.

BY CURTIS MORGAN
cmorgan@MiamiHerald.com

Faucets flowed with shocking pink within hours after the test dye was injected into the Biscayne Aquifer.

County administrators have long worried that the limerock industry's plans to carve up 21,000 acres of Northwest Miami-Dade posed a threat to the source of drinking water for more than one million people.

The contamination risk now appears even higher than they suspected.

New findings from federal scientists and consultants suggest a half-mile no-mining protection zone around 15 key wells in the heart of the mining district is too small. According to the draft of one county study, the zone is perhaps several miles too small.

The studies, notably a dye test that left faucets flowing shocking pink, tracked water moving far faster underground than expected -- possibly too fast for the porous limestone buffer to filter out a nasty parasite called cryptosporidium.

Miami-Dade's environmental and water directors -- and the scientists who did the studies -- stress they don't think the Northwest well field, the county's largest, is at imminent risk. Drinking water is tested 200 times a day and they see no immediate danger that the parasite -- typically passed along through human or animal waste -- will find its way into isolated rock pits and the water supply.

''Don't put out the idea that we're in a panic situation and my God, we're all going to die,'' said John Renfrow, director of Miami-Dade's Water and Sewer Department.

But the potential threat is serious enough that they recommend upgrading two water plants with expensive technology designed to kill cryptosporidium, an organism linked nationwide to outbreaks marked by severe diarrhea that can sometimes be fatal for victims with compromised immune systems. Unfortunately, the hardy infector shrugs off the chlorine commonly used to treat water from the vast underground Biscayne Aquifer.

The studies, outlined in a Renfrow memo and first reported last month by Jim DeFede on Herald news partner WFOR-Channel 4, have reopened a long-running controversy over a 77.5-square-mile swath the mining industry has dubbed the "lake belt.''

The industry supplies half the state's concrete and fill. Over the next 50 years, it envisions digging a grid of giant pits around the well field.

Environmentalists charge the county has too quickly dismissed bigger buffer zones and hasn't made it clear yet who -- the public or mining companies -- must pay a treatment bill that could range from $100 million to more than $250 million.

Brad Sewell, an attorney for the National Resources Defense Council, said the reports from the U.S. Geological Survey and engineering consultant CH2M Hill show that a few powerful companies are profiting at the expense of drinking water safety and thousands of acres of wetlands.

Environmental groups already have a lawsuit in federal court against the Army Corps of Engineers, challenging a 2002 decision to let the industry mine an initial 5,409 acres over 10 years.

''I don't see how the case can be made any clearer,'' said Sewell, who argues that the new research gives the county and the Corps ammunition to block mining in nearly a fourth of the lake belt.

ENGINEERS' REVIEW

The Corps was reviewing the studies and had not decided about revising the permits, said John Studt, chief of the Corps' south permits branch. He stressed that the Corps typically defers to local and state authorities.

Representatives of the rock miners, who have long argued that the pits pose no problems, downplayed any threat.

''For starters, it's real important to know that cryptosporidium and giardia [another parasite] have never been detected out there at all, in any of the wells, in any of the lakes. It's just not out there,'' said Tom MacVicar, a consulting engineer for the Miami-Dade Limestone Products Association, a coalition of 10 companies.

INDUSTRY'S DEFENSE

The area has been mined since the 1950s, long before wells were drilled, and the banks of one old pit are about 800 feet away from the wells, deep within the well field protection zone, MacVicar said. Yet years of industry testing show water in the quarries is actually cleaner than in canals and the famously pristine aquifer, he said, and the pits had never been linked to a water quality problem.

MacVicar said critics consistently exaggerate risks from an essential industry that is already paying $46 million in fees to create a 7,500-acre wetland preserve and will eventually turn much of the ''lake belt'' over for use as Everglades restoration and water supply reservoirs.

The existing no-mining zone is ''going to be an amazingly effective water quality buffer,'' he said.

While Broward and Monroe counties and portions of southern Palm Beach County draw water from the Biscayne, there is no suggestion they are at similar elevated risk. Conditions at the Northwest well field form what one scientist called ''a perfect storm'' -- a primary public water supply smack in the middle of the state's richest deposit of quality limerock.

The lake belt plan, first floated in 1992, took five years to write and several more to win approval from the Florida Legislature and the Army Engineers. But officials with Miami-Dade, the Florida Department of Health and the U.S. Environmental Protection Agency expressed enough concern about contamination that scientists with the USGS were contracted to take a look. A study published in November is the first of what will be several to emerge from three years of research.

The most eye-opening USGS test occured in April 2003, when a harmless red dye was injected into a test hole. It was expected to trickle underground to the wells over two, perhaps three days. Instead, a concentration that wasn't even half-diluted shot there in four to six hours, stunning scientists and residents alike by tinting canals and tap water shades of red and pink.

While the dye test made news, a later, more sophisticated, test may be the bigger red flag: It showed the limestone did only a limited job of capturing microscopic spheres precisely modeled to mimic cryptosporidium.

The upshot, supported by a report from county consultants, is that buffer zones drawn in the '80s -- before the parasite became a public health concern -- may not be big enough to guard the wells.

Carlos Espinosa, acting director of the county's Department of Environmental Resources Management, said the zones were based on predictions of how long it would take to dilute industrial chemicals or kill bacteria before they reached wells.

HARD TO CONTROL

Crypotosprodium, a single-celled protozoan that can survive for long periods in water, is a different challenge.

''We cannot control it like we can control chemicals,'' he said.

MacVicar, the mining consultant, argues the zones remain effective because they block the only potential sources of parasites, such as sewage plants and cattle pastures that let cryptosporidium enter lakes and rivers. He also questioned the value of what he called ''the pink water test,'' saying too much dye had been dumped too close to an operating well pump -- just 328 feet away. The no-mining zones are eight times larger.

Robert Renken, the lead USGS hydrologist on the study, defended the research, saying it had redefined ''our understanding of the aquifer.'' Philip Berger, an EPA hydrologist who monitored the study, agreed.

''It's sort of a rule of thumb, at least among the hydrologists, that the Biscayne Aquifer is the most transmissive aquifer in the United States,'' Berger said.

PITS ARE THE DANGER

It's critical to understand that the process of extracting rock poses no risk to the aquifer by itself, said USGS microbiologist Ronald Harvey, a study co-author. The potential problem is the pits left behind, dug 80 feet down -- the same zone wells tap.

''What that is doing is creating a window into the aquifer,'' Harvey said. "All of the sudden you have surface water that goes down to the depth of the wells.''
More pits would provide more entry points for contaminants and remove much of the limestone that now serves as a natural filter.

Renfrow acknowledged in his memo that ''mine-out'' could create such a direct connection between surface water and the aquifer that it would trigger mandatory treatment for the parasite. Federal laws call for that for any surface water used in municipal drinking water systems.

TREATMENT EFFORTS

As a ''precautionary measure,'' Renfrow wants to move toward treatment now and said he was exploring how to pay for it. Previous attempts to have the industry foot the bill have failed.

Kerri Barsh, an attorney for the limerock association, said in a written statement that the industry is open to discussions.

As for bigger buffer zones, Renfrow and Espinosa don't consider that option practical. The amount of land, they said, would be substantial -- and staggeringly expensive.

The industry, which controls much of the land in question, would demand compensation for rock 80 feet down. Barsh cited a ''conservative'' estimate for 5,000 acres: $1.75 billion, not including hundreds of millions in lost business.

UPGRADE

The county's Espinosa said a more workable solution is to upgrade treatment plants.

''You could go ahead and purchase hundreds of acres, or try to, but that would not guarantee you would have absolute protection,'' he said.

Sewell said the risk that regulators seemed most concerned about is to the industry's bottom line.

''The county wants to hide behind the Corps and the Corps wants to hide behind the county,'' he said, "and everybody wants to hide from the rock miners.''