Remnants of arsenic must be removed for safety as golf courses are converted into residential developments across Palm Beach County.

Golf course conversions are often difficult for developers. That’s because parts of the course may have arsenic on it.

"We know going in that we will probably have to spend some money to remediate," said Jonathan Grebow, whose company, Ridgewood Real Estate Partners, is involved with the conversion at the Fountains, west of Lake Worth Beach. "The cost can range from a few hundred thousand dollars to a few million dollars. You factor all that in."

Arsenic is an odorless contaminant linked to a number of cancers, according to the U.S. Environmental Protection Agency.

At the Fountains and other courses being converted to residential property in Palm Beach County, levels of arsenic have been detected, prompting a more expensive conversion.

Sometimes, Grebow said, the remediation can be so costly that a developer might just walk away from the project. But in South Florida, with the housing market as hot as it is, it is more likely that a builder will pursue the project.

In July, in addition to the Fountains, the county approved a conversion at Palm Greens west of Delray Beach. Arsenic was found there and at Polo Trace and Marina Lakes Golf Course, west of Delray Beach. Another approved conversion includes Boca Raton Municipal Golf Course, which has not yet been measured for arsenic. Nearly 1,800 residential units will be built on those five courses.

Grebow noted that a conversion project is a way to address the arsenic issue, which is why, at the end of the day, most residents welcome the conversion. Otherwise, there is no obligation to remediate, Grebow said, and the arsenic remains.

Grebow said there is arsenic in parts of the Fountains course he wants to develop. Exactly how much will be removed has not been decided. At another section of the golf course where developer GL Homes wants to build, testing also indicated that arsenic exists in a number of places that will need remediation.

Howard Nelson, a Miami-based environmental lawyer with the firm of Bilzin Sumberg, noted most of the land in Palm Beach County west of I-95 has levels of arsenic in it because much of the land was once used for farming — and farmers used herbicides containing arsenic to grow their crops. Golf courses often used arsenic-related herbicides in the 1970s and ’80s. Also, arsenic is a naturally occurring substance.

Arsenic contamination on golf courses almost always generates some angst among area residents when they hear of development plans. But Florida DEP spokeswoman Jill Margoulis said that with appropriate remediation and planning, "these types of sites can be safely re-purposed if engineered correctly."

Nelson said that golfers need not worry about golfing on courses that may have some levels of arsenic on them. The issue is when you disturb the ground and it can get in the air, he explained, and even then, as long as the remediation is done correctly, there should not be a problem. Often, the developer is required to include a dust-control plan.

Before building can begin, the developer must provide DEP with a site-assessment report from an environmental engineering firm identifying herbicides used, how long the golf course has been operating and whether contaminates are leaching into the groundwater. DEP then reviews the report and determines what remediation must be done.

Margoulis noted remediation requirements depend on the intended use of the property. Cleanup levels are stricter for residential development.

Nelson said there are a number of ways to remediate. One option is to take all of the soil off the property, which, he said, is rarely done because it is very expensive.

Another option, he explained, is to cap the site with clean fill on top of the contaminated soil.

The most frequently used method is to mix the contaminated soil with clean soil. And if there are hot spots, he may recommend to the builder that contaminated soil be removed. Grebow said that the option of mixing the soil with clean soil is the option that will be used at the Fountains.

At Avalon Trails, more than 4,000 tons of soil were removed from the shuttered Marina Lakes Golf Course west of Delray Beach after arsenic was detected, according to reports submitted to DEP. And at Polo Trace, the upper 6 inches of soils at the golf course were removed throughout the site after arsenic was found. According to reports submitted to the state, the cleanup plan was "effective."

For a residential project, the regulatory limit is 2.1 parts of arsenic per million. Nelson said that parts of golf courses are relatively clean, noting that when the regulatory limit is exceeded, contaminated soil is often removed.

Plans to build a Major League Soccer stadium on a Miami-owned golf course has attracted national attention after recent reports of high arsenic levels. For commercial projects, the limit is 21 parts per million, 10 times that of a residential project. The Miami golf course, unlike the ones in Palm Beach County, had ash deposits from a now-closed municipal incinerator that increased the level of contamination.

The consultant for the soccer team recommended the developer build a cap across the entire site to separate the contaminated soil from the project. Nelson, who is not involved in the project, noted that the remedy there could very well be the 16 to 24 inches of concrete that will cover much of the golf course to serve as a base for the soccer stadium. "That should be a very good cap," he noted.