Water Monitoring Post-herbicide Application 2012

NYS Department of Environmental Conservation, Tompkins County Soil and Water Conservation District, Tompkins County Health Dept.  (TCHD), and the Ithaca Area Wastewater Treatment Facility are working together to monitor the levels of endothall (trade name Aquathol-K) and fluridone (Sonar Genesis liquid, Sonar One pellets) in and beyond the herbicide treatment area. The Dept. of Environmental Conservation (DEC) and Tompkins County Dept. of Health (TCHD) developed the monitoring protocols, which are part of the DEC permit to use the herbicides. TCHD and DEC are working in tandem to get the fullest picture of the spread of the herbicides. The collected water samples are analyzed by the Community Science Institute (CSI) and then sent to Tompkins County Soil and Water Conservation District. (Results) 

Monitoring both herbicides was based on 3 different criteria:

• Environmental Protection (DEC sites)
• Drinking Water Safety (TCHD sites)
• Adequate levels in order to be effective (concentration sites via CSI & SePRO)

DEC monitoring focuses on environmental protection. On DEC's behalf, the Tompkins County Soil and Water Conservation District collected water samples from the shore at six locations (blue triangles on the endothall map and yellow circles on fluridone map) adjacent to the area of herbicide treatment (yellow outline).  The DEC sites are upstream and downstream of the treatment areas, as well as upstream on Cascadilla and Sixmile Creeks. The red triangles on the endothall map show areas where the herbicide concentration was checked to make sure it was not too weak or too strong.

Water samples required for DEC will be taken 24, 48, 72, and 96 hours after the endothall application, and on day 7, 14 and 21. The laboratory used could detect endothall as low as 7 parts per billion (ppb).

TCHD efforts focus on protecting drinking water. Water quality samples are collected on day 1, 3, 7, 10, and 14 at 3 locations in the treatment area and at the Bolton Point water supply intake. NYS law requires that endothall levels in drinking water be below 50 parts per billion (ppb). Tompkins County Health Dept.'s Endothall Water Quality Plan, April 2012

Water monitoring continued throughout the 4 month (July-October) fluridone treatment. Water samples were collected before the application, every 24 hours for the first 72 hours (7/13 through 7/15), and weekly to make sure the concentration is within its effective range (2-8ppb) at the SePRO in-treatment sites (red circles on map) and the same DEC sites (yellow circles on map). When the concentrations were found to below this range, alterations to the treatment were made. These same sites were tracked by TCHD for drinking water safety (though well below MCL).

The analysis being used, ELISA (enzymed-linked immunosorbent assay), is the same as that used last year. It was chosen because it renders analytical results comparatively quickly, thereby enabling rapid reporting to the public. This method is not currently certifiable in NY state so, as previously, selected samples are being "split" and the duplicates are sent to a laboratory that is certified by NYSDOH's Environmental Laboratory Approval Program (ELAP) to conduct EPA method 548.1. This method employs gas chromatography/mass spectrometry (GC/MS) to quantify endothall/fluridone in drinking water. The split-sample process is being applied to samples taken from Bolton Point as an extra precaution at TCHD and DEC's request. The results from both labs should be similar and, where applicable, both sets of results will be reported.

Bolton Point collected a sample from their intake prior to the treatment on June 19.

Results

• Endothall results -- Monitoring completed
• Fluridone results  -- Monitoring completed November 26 (all sites <1ppb)

* Changes have been made to the fluridone result table since additional monitoring points have been added in the "donut" at the mouth of the inlet, replacing other monitoring points that are and will be discontinued throughout the next few weeks.  (Sept. 2012)

Note: data is added to the spread sheet as it becomes available. There are future dates with no data indicating upcoming results that will be supplied once collected

Last Updated: January 18, 2013