In addition to DOM content, the other major difference between un altered
SNARC and WARU water was the concentration of divalent cations.
As described above,WARU water was pumped from a region of the
Sparta Sand Aquifer known to yield very soft waters whereas the SNARC
water was pumped from a region yielding waters of moderate hardness
(Table 1). Divalent cations, in particular dissolved calcium, are known to
affect bacterial adhesion to inert and living surfaces