E. Occurrence and Mobility of Uranium and Other Elements in the Grand Canyon Springs

Multiple chemical parameters coupled with multivariate statistical techniques are used to identify a signature of anthropogenic disturbance in spring water emanating from the walls of the Grand Canyon.   Due to past uranium mining activity within and near the Grand Canyon, a current increase in local uranium claims, and increased pumping of the regional aquifer system (Redwall-Muav), the Grand Canyon springs may be in danger of contamination, reduced flows, or possibly extinction.

It is important to develop identifiable chemical indicators in spring water which accurately portray hydrologic connection, anthropogenic influence, and chemical alteration.  Distinguishing background concentrations of potential contaminants from those produced and elevated from mining activities is particularly important in the Grand Canyon.  Previous investigators report elevated uranium concentrations several of the Grand Canyon springs.  These springs are generally within close proximity to historical uranium mines or their associated ore bodies (breccia pipes).  The breccia pipes, containing fractures and void spaces, act as conduits for groundwater recharge.  Horn Spring emanates from the Redwall-Muav aquifer just below the historical Orphan Uranium Mine and has exceeded uranium concentrations in excess of EPA clean drinking water standards.  In addition, other geochemical constituents of Horn Spring have been identified as anomalous to proximal springs emanating from the same aquifer. 

The objective of this research is to evaluate the groundwater mobility of uranium and other elements appearing in Horn Spring and other select Grand Canyon springs, by using multivariate geochemical and statistical analytical techniques. The hypothesis to be tested is that elevated uranium concentrations in selected Canyon springs are the result of enhanced preferential flow and dissolution in breccia pipes affected by past mining activities.  This proposed work will address the question of hydrologic and chemical alteration of groundwater by mining activity and the potential resultant degradation of springs.