Pesticides in Upstate New York's Ground
County was chosen for study because of the elevated intensity use
of pesticides more likely to be mobile and persistent, as shown on
the Groundwater Ubiquity Score (GUS)-weighted overview
maps. The county's population center in the
city of Batavia depends partly on ground water and partly on
Tonawanda Creek for community and private water supplies. Some villages
in the eastern half of the county use surface water sources, including
connections to the Monroe County Water Authority which draws from Lake
Ontario. Private wells serve rural residents, campgrounds, and hamlets.
Genesee County's most prominent ground
water features are a large primary sand and gravel water supply aquifer
in the Batavia area and the Onondaga Limestone formation that runs in
an east-west band across the center of the county. The Limestone has
many sinkholes, some of which overflow in the springtime, and
some of which occur in river beds, causing losses of streamflow into
bedrock. Landuse is dominated by agriculture, particularly dairy, cash
crops and vegetables. From the air (below), the agricultural land use
pattern is striking, in some areas covering nearly 100% of the land
with cropped fields.
We had the priviledge of working with
the County Soil
and Water Conservation District (SWCD) and the County
Health Department. The SWCD recommended candidate sites and the
Health Department sampled the wells of those landowners who consented
Genesee County was the site of the
first well sampled to date that had levels detected by the DEC laboratory, with 2 micrograms/liter
of the herbicide metolachlor. ELISA
immunoassay results for that well were similar, as were resampling
results two months later. A shallow well casing and nearby pesticide
use apparently contributed to this case. There is no drinking
water standard for metolachlor. The only other detections in the county
were nonquantifiable traces of atrazine in one well and in the
resampling of the well where metolachlor wherein was detected. Nitrate levels were rather high in some
areas, with multiple wells (including the one with quantified
metolachlor) having over 10 mg/L of nitrate-N. Property owners with
wells having over 6 mg N/L nitrate were given a Cornell fact sheet (PDF) about
nitrate and health.
Overall, the level of detections was low
despite the very high GUS-intensity map. Genesee county was thus
the fifth county where testing of rural wells for pesticide residues
found little evidence of contamination concerns.
This round 5 work in Genesee County
was followed by work in Wayne County.
Aerial view of Batavia area (lower left). Horizontal
band across center is NYS Thruway.