Florida Revisits Arsenic Issue

Florida’s Department of Environmental Protection (FDEP) has held a series of workshops on updated guidelines for the concentrations of various chemicals that can be present in soil suitable for unrestricted use. These guidelines are widely used in determining suitability of soil materials in the state, including Recovered Screened Material (RSM), a product created by mixed C&D recyclers.

The agency anticipates a regulatory adoption hearing in August. While there have been changes across the board for FDEP’s risk-based values, those for arsenic are of the greatest to C&D recyclers, since treated lumber and other sources can introduce trace amounts of arsenic to RSM.

Recycling advocates had been concerned that the FDEP was relying on generic assumptions in calculating soil guidelines that have resulted in very low values for arsenic, similar to natural background levels in the state. Recyclers handling soil materials and RSM in Florida have complained that the application of the current guidelines for soil arsenic to these materials creates a stigma that affects their markets even while some new soil materials, where naturally occurring arsenic can also exceed the current guidelines, are not subject to similar pressures or regulatory attention.

Recognizing that their current guidelines over-emphasize risks from soil arsenic because of differences in exposure from soil versus arsenic dissolved in water, FDEP sponsored a study at the University of Florida to carry out the first direct analysis of arsenic uptake (bioavailability) from Florida soils. Published last year, the study found that the bioavailability of arsenic from Florida soils ranged from about 10 to 25 percent of the uptake from water.

Based on a review of the Florida-specific findings, an advisory panel recommended that the state’s soil guidelines be adjusted to account for 25 percent bioavailability for soil arsenic. Using FDEP’s equations, this amounts to roughly a four-fold increase in the risk-based soil arsenic guidelines: 2.8 ppm (parts per million) for residential use, 16 ppm for commercial/industrial use. The panel’s recommendations are available on the Web at http://www.dep.state.fl.us/waste/quick_topics/publications/wc/csf/ruddell_cover_ltr_3-7-03.pdf.

While these values are still low compared with guidelines and natural background soil arsenic levels in some other states, the revisions are expected to address recycler concerns about limitations on materials that do not exceed natural levels of arsenic. According to panel chairman and environmental consultant Dr. Robert DeMott, “the previous lack of a soil bioavailability fraction for arsenic made the current guidelines so close to common, naturally occurring background soil levels in Florida [that] it’s been hard to ensure that we are not drawing regulatory attention to soils with natural levels of arsenic. The recommended changes are a step forward since the regulatory criteria would be functionally higher than natural background for most of Florida.”

Florida recyclers have supported the chemical-specific evaluation of soil arsenic and are expected to actively support incorporation of the recommended revisions during adoption hearings. Adoption would help reduce one barrier to the use of recycled soil materials.