il-june-18

egularly evaluated. To date, no study has been
conducted to approximate the likelihood of
illness in people that consume fresh produce
that has been irrigated with water at different
indicator E. coli concentrations.
Before the hard work of understanding risk
to consumers can be done, however, we need
to first understand the quality of irrigation
water supplies across the United States. This
is where irrigation districts in California and
Washington have been helping. Following the
release of the Produce Safety Rule and the
subsequent AWP, my colleagues and I began
actively pursuing irrigation districts across the
western United States as partners in research.
Since that time, we have successfully completed
a multistate survey of indicators and pathogens
in surface irrigation water supplies, followed
by a multiyear study to validate the use of data
sharing as allowed under section 112.47(a)(2)
of the rule. Specifically, this provision allows
growers to collaboratively monitor their water
ABOVE: Melissa Partyka.
The
microbial
quality of
irrigation
water
supplies
is at the
heart of the
matter.
—MELISSA
PARTYKA
supplies, provided there are no reasonably
foreseeable sources of contamination in
between monitoring locations. In short, this
means that growers along an irrigation canal
or a piped lateral can all share their data and
dramatically reduce the burden on any one
grower. Without preliminary data, however,
it is unclear how far away growers can be
from one another and still collaborate, or
even which factors along a canal should be
considered “reasonably foreseeable sources of
contamination.” We are actively analyzing our
data collected from eight districts over 3 years
to provide guidance on these questions and
help growers begin the work of complying with
the AWP. But much more work remains.
Though we currently enjoy ample
participation, it took us years to gain the
trust of enough districts to make a robust
study possible. In western states, irrigation
districts are a gateway that researchers must
pass through to gain access to surface water
distribution networks. Though the AWP
places the sole responsibility of water testing
on the grower, in the West the source of
many growers’ water is under irrigation
district control. Partnering with irrigation
districts is also much more efficient for
researchers, since districts already have a
built-in relationship with growers and can act
as honest brokers of information. However,
fear of potential liability has led some districts
to respectfully decline opportunities for
Food Safety Modernization Act–related
collaboration. Thus, the science of agricultural
water tends to be concentrated in a few
research-friendly irrigation districts, reducing
our ability to capture the broad diversity of
agricultural water conditions experienced by
the majority of produce growers. Even with
access and helpful partners, public funding
for this type of research is extremely limited,
and research takes time. Again, districts may
be able to help by lobbying state and federal
legislators for increased funding for rigorous,
and ultimately publishable, research of surface
water irrigation supplies. But for now, growers
and regulators will have to make do with the
best available research and hope for better. IL
Dr. Melissa Partyka is an extension specialist
at Auburn University and is an affiliate for
the UC Davis Western Institute for Food
Safety and Security. She can be reached at
m.partyka@auburn.edu.
IRRIGATION LEADER 19