Kh. Johannesson et al., MULTIVARIATE STATISTICAL-ANALYSIS OF ARSENIC AND SELENIUM CONCENTRATIONS IN GROUNDWATERS FROM SOUTH-CENTRAL NEVADA AND DEATH-VALLEY, CALIFORNIA, Journal of hydrology, 178(1-4), 1996, pp. 181-204
Arsenic and selenium concentrations along with the major solutes were
measured in groundwaters sampled from springs in Pahranagat Valley and
Ash Meadows, Nevada, Death Valley, California, and from wells from th
e Nevada Test Site and Yucca Mountain, Nevada. The multivariate statis
tical technique correspondence analysis was applied to the data to det
ermine relationships between the groundwaters from these areas, the aq
uifer materials and the As and Se concentrations, and to examine the r
elationships between As and Se and the other chemical parameters inclu
ded in the statistical analysis. The correspondence analysis indicates
that a strong relationship exists between chloride and Se in the grou
ndwaters and that As is not associated with chloride. The strong assoc
iation between chloride and Se suggests that Se behaves more conservat
ively than As in these oxygenated, circumneutral pH groundwaters. No s
trong association was observed between the As and/or Se concentrations
of the groundwaters and the aquifer material with which these waters
interact (i.e. regional Paleozoic carbonate aquifer, Tertiary tuffaceo
us volcanic rocks, and/or basin-fill deposits). However, it is likely
that sampling of groundwaters from the various aquifers was insufficie
nt to determine relationships between the aquifer materials and ground
water chemistry. Associations were observed between the groundwaters o
f the Nevada Test Site and Yucca Mountain regions and the groundwaters
of the regional carbonate aquifer that discharge at Ash Meadows and D
eath Valley, suggesting mixing of these waters. Groundwater from the r
egional carbonate aquifer in Pahranagat Valley, which is upgradient fr
om the Nevada Test Site, Yucca Mountain, Ash Meadows, and Death Valley
, exhibited no association with groundwaters from these regions.