Interactive Effects of Fumigants

Project Description

Exposure to Multiple Fumigants is Common

Simultaneous exposure to multiple fumigant pesticides occurs when fumigants are co-applied as mixtures or when applications of different fumigants occur in close proximity to each other. The maps below allow viewing of fumigant use by week in selected townships, a six square mile area. Zoom in on a block of interest and click on the block to display a chart of fumigant use by week for the top weeks in 2013. The data show that exposure to multiple fumigant pesticides is common, especially in high fumigant-use areas such as California’s Central Coast and South Coast regions.

Report on Potential for Interactive Effects of Fumigant Pesticides

The Sustainable Technology & Policy Program (STPP) at UCLA released a report—Exposure and Interaction: The Potential Health Impacts of Using Multiple Pesticides— on the combined effects of exposure to multiple pesticides, using fumigants as a case study. PRI was a co-author on the report.

Despite the fact that we are all exposed to hundreds, if not thousands of chemicals, chemical compounds are largely assessed and regulated individually. Increasingly, there is evidence that exposure to multiple chemicals, even low level exposure to those considered benign, could lead to human health effects.

In this report, the Sustainable Technology & Policy Program (STPP) at UCLA explores the issue of multiple exposures through a case study of three commonly used pesticides in California, chloropicrin, 1,3-dichloropropene (Telone®), and metam sodium.

Methods and Data Selection

The source of the data used to make these maps is the California Department of Pesticide Regulation’s California Pesticide Use Reporting Data for 2013. Please refer to A Guide to Pesticide Reporting Regulation in California, and the California Department of Pesticide Regulation’s User Guide for more details about the data set.

The data include the pounds of the following soil fumigants used in 2013, the latest year for which data are available:

  • Metam Salts (Sodium and Potassium)
  • Chloropicrin
  • 1,3-Dichloropropene (Telone)
  • Methyl bromide

Fumigant use was summed for all applications during each week and aggregated by township, which is an area 6 mi x 6 mi in size. The township is defined by Meridian, Township, and Range according to the system established by the United States Public Land Survey (USPLS), and used by the Department of Pesticide Regulation. See a description of this system.

The charts display use of each fumigant by week for the 10 weeks with the highest fumigant use. If fumigants were used for fewer than 10 weeks in that township, the chart displays only the weeks in which fumigants were used.