Dichlorvos (DDVP) Risk Characterization Document - California ...

food service facilities); hand-held application to farm livestock (except poultry); use on turf, ornamental
lawns and plants; use in airplanes; pet flea collars; and use in trucks, shipholds, and railcars.
Restrictions were placed on the use of DDVP in greenhouses and mushroom houses, passenger
buses, kennels, feedlots, animal premises, livestock, manure, and garbage dumps.
The oral reference dose (RfD) of 0.0005 mg/kg-day previously set for DDVP has been withdrawn by
the USEPA pending further review of the data (USEPA, 1993a). The World Health Organization
(WHO) acceptable daily intake (ADI) is 0.004 mg/kg-day (WHO, 1993) based on the absence of
erythrocyte ChE inhibition in human volunteers given DDVP 0.9 mg three times a day for 21 days
(Boyer et al., 1977). The Permissable Exposure Level (PEL) in the air for occupational exposure is
0.1 ppm (0.9 mg/m 3 ) set by the American Conference of Governmental Industrial Hygienists and
required by the California Department of Occupational Health Administration (Barclays California
Code of Regulations, 1991).
C. TECHNICAL AND PRODUCT FORMULATIONS
Amvac Chemical Corp. is the primary registrant for technical DDVP in the US (Farm Chemicals
Handbook, 1991). In addition to technical DDVP, DDVP is found in liquid formulations, resin strips,
flea collars, foggers, and pressurized sprays.
D. USAGE
In California, the reported use was 5900, 5700, and 3600 pounds for 1991, 1992, and 1993,
respectively (DPR, 1993). The major uses are for pest control in structures and on livestock (cattle
and poultry), each use accounting for 30-40% of total pounds. The only direct food uses were on
cucumbers, nut crops, and processed commodities and were 10% or less of the total. Lesser
amounts are used in landscape maintenance, in nursery (non-food), and other pest control sites.
The use of DDVP on mushrooms and figs is no longer on the California registered labels. The only
greenhouse use formulations were Flora-Fog for cucumbers, tomatoes, lettuce, and radishes and
GH-19 for tomatoes. The application rate was 1 ounce/3000 ft 3 (or 1 gm/1000 ft 3 ) and the preharvest
interval for both products was 24 hours after application. There is no pre-slaughter interval for the use
of DDVP directly on the skin of livestock. Label instructions include directions to use an approved
cleaning solution to clean teats prior to milking.
E. ILLNESS REPORTS
From 1982 to 1990, 78 cases of human illness and/or injury were reported to the California Pesticide
Illness Surveillance Program that were associated with exposure to DDVP (Mehler, 1993; Appendix
B). The cases included 60 systemic illnesses, 12 eye injuries, and 6 skin injuries. No hospitalizations
were reported and only 1-2 work day losses for 5 cases. A survey of poison control centers showed
several reports of children who chewed on DDVP-containing resin strips, but without clinical
symptoms (Gillette, 1972). Ingestion of 400 mg/kg DDVP was lethal to a man in a suicide, while 100
mg/kg was sublethal to a woman who survived after intensive treatment (Hayes, 1982).
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