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Water Sample Analysis Results - Croton River Hydrilla Project

Water sample analysis reports regarding the Croton River Hydrilla Control Project can be found below. Each PDF corresponds to an individual analysis result and the date it was collected. Samples were collected by SOLitude Lake Management and Village of Croton on Hudson staff from Village drinking water wells and tested by Phoenix Environmental Laboratories in Manchester, CT. Please contact the DEC Invasive Species Section or refer to the project webpage for additional information.

Fluridone Detection Thresholds

  • no fluridone detected in drinking water: "not detected"
  • 1 ppb (parts per billion) or lower: "normal," treatment continues as planned
  • greater than 1 ppb but less than 4 ppb: "additional monitoring necessary," sampling analysis will occur on a daily basis
  • exceed 4 ppb: "treatment plan will be modified or terminated"

Water Analysis Results

Residents should not water any plants (lawns, gardens, nurseries, greenhouses) with river water because concentrations of the herbicide, fluridone, in the river may damage some plants. Fluridone has been detected in pre-treatment water (Village of Croton wells) at a concentration of 1-1.4 parts per billion (ppb), which is far below the USEPA label restriction of 20 ppb. The concentration of fluridone in post-treatment drinking water delivered to the community (tap water), is lower than the concentrations in any of the wells and there are no restrictions on the use of post-treatment drinking water.

*Please note: Samples are not collected on days when treatment is temporarily suspended due to high flows in the river.