Heavy Metal Contamination in Colorado
By Larry Renshaw
I just read an article in the Summer 1990 issue of "Mushroom - The Journal of Wild Mushrooming", about radioactivity in mushrooms. The article recaps research done in Europe after the Chernobyl nuclear accident in the Soviet Union. The research indicates that some types of mushrooms accumulated a significant amount of radioactive heavy metals.
The article also mentions that "The accumulation by higher fungi of trace elements, particularly toxic metals such as mercury and cadmium, has attracted considerable attention during the last fifteen years. This affinity for a given element or a group of elements is generally species- and, to a lesser extent, genus-dependent." This comment prompted me to think about mushroom gathering in the Colorado Rockies. Colorado has a rich mining heritage throughout the state. Many Colorado communities started life as mining towns. Central City, Georgetown, Cripple Creek, Leadville, Telluride are just a few city that come to mind.
This mining legacy is causing heavy metal pollution that is still occurring today. The Environmental Protection Agency has declared the Yak Tunnel near Leadville a Super-Fund cleanup site because of the large amounts of heavy metals still being released there. Heavy metal ingestion causes a variety of illnesses in humans that are largely irreversible.
The research indicated that different species of mushrooms accumulate heavy metals differently. Agaricus campestris and Agaricus bisporus don't accumulate significant quantities of heavy metals, while Leccinum and Boletus species such as Boletus edulis can accumulate relatively large amounts of heavy metals.
Traces of heavy metal pollution can usually be seen on the rocks of a stream as discoloration of the rocks' original colors. It is usually a dingy orange color, although I have seen a dark grayish discoloration on occasion. It seems to me that common sense indicates that we mushroom hunters should avoid collecting mushrooms along the banks of stream beds that have visible rock discoloration. Isn't it better to be safe than sorry?
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