Trace elements in kidney stones from three areas in the United States.

A large number of trace elements has been found in calcium stones (whewellite, weddellite, and apatite) and in struvite. Significantly fewer elements, with lower abundances, are found in uric acid and cystine. With the exception of four trace elements (lead, silicon, strontium, and zine), the trace element assemblages are identical in the oxalates (whewellite and weddellite); struvite is also similar but with notable exceptions. In general, apatite contains approximately twice the level of trace element abundances as do the oxalates. This study is based on the distribution of 20 elements in 186 mimeralogically identified urinary calculi from three generalized areas of the United States (northeast, southeast, and midwest). In general, there is no statistical difference in the trace element assemblages of mineralogically identical stones from the three areas.