Lakes

1. Objectives and priority

  • Obtain recurring data about pesticide concentrations in a few diverse, small to medium scale lakes.

This is the third priority of the project, representing 5-10% of the samples taken over time.

This is an adjunct to New York’s Citizens Statewide Lake Assessment Program, involving veteran sampling volunteer teams and Cornell personnel.

2. Design, approach, recruiting

The contract specified four lakes sampled once per year at two sampling points each. We varied from this to reflect conditions at the actual lakes chosen and the perspectives of volunteers at two lakes. Four lakes cannot hope to represent the hundreds of greatly varied lakes in Upstate New York, thus we simply tried to span geography, from almost Lake Erie to almost the Connecticut border, and sizes from 0.2 to 21 square miles. The first sampling year, 2022, can be considered a pilot effort.

Figure 1: Four lakes for 2022

Figure 2: Sampling approaches for 2022

We are essentially repeating the 2022 approaches for 2023.

3. Sampling

Volunteers and Cornell SWL staff sample using Kemmerer samplers from boats. The standard depth of sampling is for the top of the cylinder to be 1.5 meters below the water surface (using a graduated cable).

Kemmerer sampler source USGS

Cornell staff sampled two northern tributaries and the outlet of Canadarago Lake from bridges instead of using a boat, using Kemmerer or a peristaltic pump.

Figure 3: Sampling Canadarago Lake tributary from bridge

4. Results and interpretations

The 2022 analyte list (shown in the categoricals page), based mostly on categorical groundwater sites, was too short to provide insights about pesticide content of lakes. 2022 samples are later being analyzed for an extended list.

For the four lakes sampled, samples from three lakes were positive for degradation products or pesticides (Table 1). All samples in Little York Lake showed a low concentration of porpular herbicide breakdown product Metolachlor ESA. Chautauqua Lake had a low concentration of popular insecticide Imidacloprid in one of four samples. The low concentration of fungicide Mefentrifluconazole in one Lake Waccabuc sample may originate from a nearby golf course.

Table 1: First-year (2022) pesticide concentrations in lakes (all values as micrograms per L; “<nnn” indicates not detected, below stated detection limit of nnn))
Lake Point In Site Date Sampled S-Metolachlor Mefen-trifluconazole Metolachlor OA Metolachlor ESA Imida-cloprid
Chautauqua Shallow CHQ 7/31/2022 <0.025 <0.025 <0.1 <0.15 0.040
Little York Point 1 6/15/2022 <0.025 <0.025 <0.1 0.321 <0.025
Little York Point 2 6/15/2022 <0.025 <0.025 <0.1 0.306 <0.025
Little York Point 3 6/15/2022 <0.025 <0.025 <0.1 0.279 <0.025
Little York Point 4 6/15/2022 0.031 <0.025 <0.1 0.278 <0.025
Waccabuc Tribs 9/7/2022 <0.025 0.026 <0.1 <0.15 <0.025

Last updated: 2023-09-22, sp17 AT cornell.edu.