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Infographic: Pesticide Movement in the Environment

What is the Herbicide Properties Tool (HPT)?

Users of of the Herbicide Properties Tool (HPT) can compare herbicide active ingredients by water solubility, half-life, sorption potential, and other factors. These properties can help to predict an herbicide's movement through soil, water, and air. This movement is also known as environmental fate.

Who can use the HPT?

The HPT was created for pesticide users or other decision-makers who may need to compare herbicide active ingredients based on how they move or break down in the environment.

How do I use the HPT?

Search for an active ingredient by scrolling through the list of active ingredients or using the search box above the list. Clicking the active ingredient name will open a pop-up box with the ingredient’s chemical properties.

The following table describes the chemical properties displayed in the HPT. These properties may be helpful when estimating pesticide movement in the environment.

Active Ingredient Property (Click the links in this column for additional explanation about the property.)

Click on the active ingredient name to see the CAS (Chemical Abstract Service) number and all property values available in this tool.

Water Solubility (mg/L)

Water solubility is how much of a chemical dissolves into water. This can determine how much will move with water through the environment.

  • Low water solubility: less than 10 mg/L or 10 ppm
  • Moderate water solubility:10-1,000 mg/L or 10-1,000 ppm
  • High water solubility: more than 1,000 mg/L or 1,000 ppm

Vapor Pressure

(mmHg at 25°C)

Vapor pressure is how much of a chemical "evaporates" or turns into a vapor and gets in the air.

Hydrolysis half-life (days)

Hydrolysis half-life is how quickly a chemical breaks down in water.

Koc for clay, silty/loam, sandy, or unknown soil types

Koc is a value to represent how well a pesticide will bind (or sorb) to soil particles.

  • Low: below 1,000 (does not sorb well to soil)
  • Moderate: 1,000-10,000 (moderate sorption to soil)
  • High: over 10,000 (sorbs well to soil)

Half-life for clay, silty/loam, sandy, or unknown soil types

Half-life is how quickly a chemical breaks down in different soil types.

Groundwater Ubiquity Score (GUS) for clay, silty/loam, sandy, or unknown soil types

The Groundwater Ubiquity Score (GUS) is how likely a chemical is to move through soil toward groundwater. The GUS considers many factors such as soil type and solubility.

  • Extremely Low: less than 0
  • Low: 0 – 1.8
  • Moderate: 1.8 – 2.8
  • High: above 2.8

What else should I consider when thinking about how a pesticide moves in the environment?

Keep these tips in mind when using pesticide products:

For help interpreting HPT values or have questions about any pesticide-related topic, please call NPIC at 800-858-7378 (8:00am - 12:00pm PST), or email at npic@ace.orst.edu.

Last updated November 12, 2022