Reactive Silica

Silica in water is present mostly as reactive or
dissolved silica. In surface waters, a small quantity
of non-reactive silica (in colloidal dimensions)
may also be present during some parts of the
year, especially during the monsoon.
As water passes through and over various soils
into our lakes and rivers, the formation of carbon
dioxide and organic acids resulting from
microbial activity results in acid degradation of
the silicate minerals (particularly clay particles).
This acid attack on minerals will dissolve the iron,
aluminum etc. and interaction of these
components with silica results in the formation of
colloidal silica that is stabilised with a coating of
organic matter.