NEWS OF THE WEEK ENVIRONMENT
SUSPECT Once heat-processed, kelp and seaweed may be one of the "unknown" sources of dioxins.
FEED SUPPLEMENT CONTAINS DIOXINS Routine monitoring in Ireland uncovers contamination
A
LIVESTOCK FEED SUPPLE-
ment made from copper sulfate and kelp has been found to contain relatively high levels of dioxins. The levels in the supplement—measured as dioxin toxic equivalents—range be tween 15 ppt and 5 ppb, said Hillary Carpenter, a toxicologist with the Minnesota Department of Health, at a National Academy of Sciences workshop last week. The supplement was manu factured by QualiTech, Chaska, Minn., and sold to U.S. farmers and feed companies. It was also
CHEMICAL
exported to seven countries. The dioxin contamination was dis covered by the Irish government during routine monitoring. Al though the level sounds low, just 10,000 bags of the most con taminated feed supplement could contain more dioxins than are produced in one year by all U.S. pulp and paper mills. The FDA limit for dioxin in meat is 1 ppt. The supplement was produced by heating a mixture of kelp (which has a chlorine content of about 4%), water, and copper sul fate to temperatures between 350
WEAPONS
NEUTRALIZATION TOPS INCINERATION For the first time, this method will be used to destroy chemical weapons
IN STORAGE The Army prefers to incinerate its stockpiles of mustard gas, such as these at the Deseret Depot in Utah, but neutral ization is favored by many local communities.
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C&EN
/ APRIL
8,
U
NDERSECRETARY OF DEFENSE
Edward C. (Pete) Aldridge has recommended that mu nitions containing mustard gas stored at the Pueblo Army De pot in Colorado be destroyed us ing water-based neutralization
2002
followed by biotreatment. Com munity and political pressure forced the rejection of the Army's preferred option: incineration. This is the first time since the Army began its chemical weapons destruction program in 1984 that neutralization has been selected as the destruction method for agentcontaining munitions. Previously the Army chose to neutralize mus tard gas and VX nerve gas stored, respectively in bulk containers in Maryland and Indiana. The Pueblo depot stores 2,611 tons of mustard gas in 780,000 munitions. Getting the relevant permits and constructing the neutralization facility will take
and 700 °F. Ideal temperatures for dioxin formation lie between 570 and 1,290 °F. Last month, FDA issued a voluntary world wide recall for the feed supple ment, and Quali Tech has shut down all operations involving heat. EPA is running tests to deter mine how the dioxins were formed under the specific conditions used at Quali Tech.
