U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings
of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993,
Water-Resources Investigations Report 94-4015
Transport of Indigenous Protozoa in a Sandy Aquifer, Cape Cod,
Ronald W. Harvey (U.S. Geological Survey, Boulder, Colo.), Nancy
E. Kinner (Dept. of Civil Engineering, Univ. of New Hampshire, Durham, N.
H.), Dan MacDonald (Dept. of Civil Engineering, Univ. of New Hampshire,
Durham, N. H.), Amoret L. Bunn (Dept. of Civil Engineering, Univ. of New
Hampshire, Durham, N. H.), and David W. Metge (U.S. Geological Survey, Boulder,
Transport of flagellates in sandy, organically contaminated aquifer sediments
was investigated in a small-scale (2 m travel distance) natural-gradient
tracer test in Cape Cod. The flagellates (average cell size, 2-3 mm), which
appear to be common in the Cape Cod aquifer, were grown in Cerophyl, labeled
with hydroethidine (a vital eukaryotic stain), and coinjected into aquifer
sediments along with a conservative tracer (bromide). Rates of immobilization
in undisturbed aquifer sediments were more than two orders of magnitude
greater than those observed earlier for indigenous ground-water bacteria.
The high rate of immobilization appeared to be related to the surface chemistries
of the flagellates and not their size. Retardation for the flagellates was
two- to three-fold greater than that generally observed for indigenous groundwater
bacteria. Apparent dispersion was also significantly greater for the flagellates
than for the bacteria and was much closer to that observed earlier for highly
surface-active, microbial-sized, carboxylated-latex microspheres. The data
suggest that flagellates are probably transported slowly through the aquifer.