Environmental Health & Safety

Resin targets perchlorate

Nov 12, 2004

Researchers at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tenn., have developed a system to clean up perchlorate pollution. Scientists may also be able to determine whether the contamination is natural or man-made. The system was named one of R&D magazine’s top 100 inventions for 2004.

Conventional applications for treating perchlorate pollution use tiny resin beads to trap the molucule, but disposal of the contaminated, spent resin can be costly and impractical.

The ORNL system removes perchlorate and breaks it down into harmless chloride and water. The resin is then recharged so it can be reused. The process costs up to 80% less than conventional methods, according to ORNL. The process of removing perchlorate also purifies it, allowing scientists to isolate trace quantities and closely examine the compound.

Perchlorate, or ClO4-is used to make solid rocket propellant and explosives, but also occurs naturally, as in nitrate soils from Chile used to produce fertilizers. This compound disrupts the thyroid gland function that regulates metabolism in adults and physical development in children. This insidious chemical is increasingly being found in soil and water, and its source is sometimes difficult to trace.

The ability to determine the source of the contamination via isotopic analysis could be instrumental in tracking environmental perchlorate to its source and resolving any liability issues, says ORNL scientist Baohua Gu, who headed development of the treatment system.

ORNL has licensed the resin technology to the Purolite Co., Bala Cynwyd, Pa., and the regeneration and recovery technology to Calgon Carbon Corp., Pittsburgh. The resin is commercially available and is being tested at two contaminated sites in California.

In 2002, the EPA proposed one part per billion as the legal limit for perchlorate in drinking water, but that standard is under debate, Gu says.