http://www.cdpr.ca.gov/docs/emon/pubs/ehapreps/report_gw09a.pdf

GW 09: Ground Water Monitoring for Imidacloprid and Four Degradates in
High Use Areas in California
Rick Bergin
Environmental Scientist
Craig Nordmark
Environmental Scientist
California Environmental Protection Agency
Department of Pesticide Regulation
Environmental Monitoring Branch
1001 I Street, PO Box 4015
Sacramento, California 95812
December 2009
Report GW 09A

Introduction
DPR’s GWPL is a list of pesticides having the potential to pollute
ground water. Pursuant to California Food and Agricultural Code (FAC)
section 13143, companies seeking to register an agricultural use
pesticide containing a new AI must send DPR mobility and persistence
data. If these data exceed certain key values and the pesticide label
requires or allows direct soil application and/or irrigation soon
after application, FAC section 13144 requires DPR to add the pesticide
to GWPL. GWPL is contained in the Title 3, California Code of
Regulations section 6800. FAC section 13148 requires DPR to monitor
pesticides on GWPL to more accurately determine the mobility and
persistence of the pesticides and determine if these pesticides have
migrated to ground waters of the state due to legal agricultural use.

Since 1990, DPR has sampled 1246 wells for 86 pesticides and pesticide
breakdown products as part of GWPL monitoring. (CDPR, 2007a).
Recently, the pesticides on the GWPL were ranked according to their
use patterns and mobility and persistence data. Those compounds with
heavy, increasing use and the ability to leach past the crop root
zone, based on the LEACHM model (Hutson 1992), are ranked higher.

Imidacloprid was selected for monitoring during fiscal year 2008─2009
based on its high ranking and the availability of a laboratory
analysis method.

The wells were also sampled for the presence of hexazinone,
tebuthiuron, the known ground water contaminants (Title 3, California
Code of Regulations section 6800[a]) and some of their degradates
(these pesticides are analyzed collectively as the “triazine screen).”
Monitoring for known ground water contaminants helps DPR assess the
adequacy of our ground water protection program and to determine if
new GWPAs need to be identified. Monitoring for hexazinone and
tebuthiuron, suspected ground water contaminants, provides additional
data on which to base a regulatory decision for those compounds, if
necessary.


Juanse Barros J.

APIZUR S.A.
Carrera 695
Gorbea - CHILE
+56-45-271693
08-3613310
http://apiaraucania.blogspot.com/
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