Recent Developments in Perchlorate Detection

Perchlorate is highly soluble and non-reactive with soil sediments. As a result perchlorate is exceedingly mobile in aqueous systems. Because of its resistance to react with other available constituents, perchlorate can persist for many decades under typical ground and surface water conditions. In 2003, the US EPA' compiled a list of potential perchlorate release sources. Sites from 25 states were listed. Table 1 summarizes the upper concentration range of perchlorate contamination found at these sites. Besides surface and groundwater, perchlorate has been found in food crops, such as lettuce, in the southwestern states. The uptake of perchlorate by crops is the result of irrigation using perchlorate contaminated water from the Colorado ~ i v e r . ~ There is a concern that perchlorate will be taken up by alfalfa, a major crop in the southwestern states. Some of this alfalfa is fed to dairy cows, which could conceivably result in perchlorate contamination of dairy products such as milk. In 2003, the presence of perchlorate in milk samples from Lubbock, TX was reported.3