permaculture

[Greg Evanylo <EVANYLO@VTVM1.CC.VT.EDU>]

David Hess writes:

<duplicated text deleted>

Aspergillus f. is a common fungus found in decaying organic matter and
soil
throughout the world - it's spores are airborne and are constantly
inhaled.
The fungus is a recognized pathogen of birds, humans and other animals
causing
acute or chronic infection primarily of the respiratory tract, viz.
aspergillo-
sis. Since A.f. is heat tolerant, it can survive the high temperatures
normally
found in the composting process.

Aspergillus f. is an opportunistic fungus or secondary pathogen which
invades
and infects debilitated or immunocompromised individuals. Rarely,
although
instances have been reported, does the disease infect nondebilitated
persons,
thus, the rationale for locating composting facilities away from
hospitals
while not ascribing any great health risk to the larger population.

The *common wisdom* is that composting facilities should not present a
threat to healthy workers et al, as long as certain precautions are
taken, i.e.
use of biofilters or other air scrubbing systems to reduce dust in
contained
areas (e.g. inside screening areas), keep outdoor windrows moist to
prevent
dusty conditions, sites should have adequate buffer areas (e.g.
separation of
facilities from residences by a wooded area), and screening of
workers.

An excellent review of this public health issue has been presented by
Eliot
Epstein in the January 1994 issue of Biocycle (pp. 51-57).  This
should serve
as another reminder that their is risk in most everything, even the
most
inocuous and beneficial appearing practices. We must decide how much
risk we
 are willing to take.