Lakes sampled for pesticides 2013, 2015-2016
PDF report: pesticides-lakes-2017
Four lakes sampled for pesticides
Why lakes?
We sampled primarily in near-shore areas that would typically host individual water intakes. We sampled shortly after major rain events so that tributary inputs of solutes and particulates would be higher than annual averages. We covered a seasonal cycle of spring, summer, and fall so as not to miss seasonally heavy pesticide use patterns in the watersheds.
Volunteers at all four lakes sampled in 2013, then volunteers from the two larger lakes again sampled in 2015-2016. The analyte list started with one dominated by agriculture, based on findings in the six rounds of private well sampling. The list was refined between the two lake periods to better represent the land use mixes in the watersheds of the two larger lakes, notably more “urban” types of active ingredients.
Results
Results were predictably related to land use:
Buckingham pond in the City of Albany is an outlier that would never have private water supply intakes. Its watershed is all developed land, but there is a park around its immediate shoreline. Just one analysis of one sample yielded a detectable amount, the widely used 2,4-D herbicide.
Petonia Lake in rural Chenango County is surrounded by large lot houses on wooded lots, and has mostly forested land in its catchment. There was a small percentage of low-intensity agriculture. This is representative of small, older recreation-oriented lakes and impoundments that are common in the Northeast US. It was unsurprising that there were no analytes detected in any sample.
Sleepy Hollow lake’s watershed has two characteristic land types: the rings of moderate sized residential lots surrounding most of the lake, and beyond that a mix of agriculture and forest land. Samples from this impoundment often had residues of agricultural herbicies and their breakdown products, all under 1 µg/L. The land use correlation is consistent with the patterns found in private wells in the earlier county-based sampling.
Lake Waccabuc’s watershed is dominated by forest land to its north, and residential land around much of its shoreline. There is a major golf course on one of the Lake’s two main tributaries. There were faint traces of atrazine in two early samples, and recurring faint traces (0.01-0.04 µg/L) of the fungicide tebuconazole in every sample during the 2013 sampling round.
The volunteer samplers were extremely dedicated and capable in this work and it would be wise to include this network again in NYSDEC’s future pesticide monitoring scheme, if there is reason to look at the especially vulnerable class of individual household water users.
After the lakes work, we transitioned from well and lake sampling to runoff sampling at Cornell research plots, focusing on the herbicide glyphosate. We also assisted NYSDEC with an imidacloprid assessment for Suffolk County of Long Island, NY.
Collage of aerial photos at four sampled lakes
Last updated 2023-09-21 sp17 AT Cornell.edu.