The California Environmental Protection
Agency Department of Pesticide Regulation has published its 1993 annual report
on the results of ground water monitoring for pesticides.
Samples were taken from 2,324 wells in 46 of California’s
58 counties: 112 pesticides and breakdown products were sought in analytical
tests, and ten compounds were found in 80 wells in 17 counties. The compounds
include the herbicides bentazon, bromacil, diuron, prometon, simazine, atrazine,
the solvent xylene and TPA (a breakdown product of the pesticide dacthal).
Breakdown products of atrazine were also found.
Where pesticide levels in water exceed ‘those considered
safe’, the department of health can take corrective action. The Department of
Pesticide Regulation can take corrective action regardless of the levels of
contamination. Corrective action includes revocation of permits to use
pesticides, modification of use practices, and suspension of a chemical’s
registration in the State.
It is much more difficult for pesticides to reach ground
water than surface waters: contributory factors include amounts used, method of
application, irrigation practices, the physiochemical properties of the
pesticide, soil type and climate.
Cal EPA, press release, 17/8/94.
[This article first appeared in Pesticides News No. 25, September 1994, page 20]