Pesticides in Upstate New York's Ground
Cortland report (PDF)
Cortland County provided a chance to
develop a pattern for work in subsequent counties in the
multi-year effort. Cornell investigators chose Cortland County for a
pilot because of prior work with the area in ground water assessment,
confidence in local agencies as partners, and the area's high
dependence on ground water. We began by enlisting the Cortland County Soil and Water Conservation
District (SWCD) to provide local insight and to recommend private
land owners to approach about sampling their wells. Having constructive
working relations with both pesticide users and well owners, a County
SWCD is an ideal partner in NY to engage a community in testing
pesticide safety of drinking water. NYS DEC and Cornell personnel had
consulted earlier with the NYS Soil and Water
Conservation Committee about the general approach of voluntary well
Cortland County's population centers --
the City of Cortland and surrounding Town of Cortlandville -- depend
completely on ground water for community and private water supply.
Their aquifer was designated as Sole Source in
1988. The Homer-Preble aquifer extends north from the City of Cortland
and similarly provides an abundant, easily tappable ground water
supply. As in most of NY, rural houses have their own wells which may
be in sand and gravel materials, or drilled into bedrock.
Cornell collected samples from 40 wells in June through
December 2003. The Cortland County work was a trial run for the State's
pesticide laboratory. Detection limits for certain classes of
pesticides were still rather high, contributing to the State lab's
finding of no residues above detection limits for 93 pesticide active
ingredients. Newer HPLC/MS-MS instrumentation with the sensitivity and
specificity necessary for this type of monitoring was on order by the
laboratory but had not yet been received, thus contributing to the
elevated detection limits. Additional tests done at Cornell using immunoassay tests found that half
of the well samples had trace detections of atrazine herbicide, but at
levels too low to quantify. These traces were less than the
assay's 0.1 µg/L (0.1 parts per billion) lower limit of
quantitation, and thus less than 1/30th of drinking water standards.
This assay is more sensitive than the State's method but less
quantitative, thus it is considered a screening method requiring
confirmation when high concentrations are found.
Cornell also tested samples for nitrate via ion chromatography. Three wells yielded
resuts above the national drinking water standard of 10 mg/L (as
nitrogen), the highest containing 12.2 mg N/L. High nitrate in wells in
this area is a recognized problem and may be from manure, agricultural
fertilizer, or onsite wastewater disposal.
We resampled eight wells in Cortland in 2009. One
contained a trace of atrazine when tested via immunoassay, and no
samples had any pesticides detected at the State lab. Nitrate results
showed some declines from 2003 levels in most of the wells resampled,
but were high enough that we provided all owners with a Cornell fact sheet (PDF) about
nitrate and health.
Cortland County set the pattern that we continued in Schenectady County.
Aerial view of Cortland, Cortlandville, and nearby