United States
Environmental Protection
Agency
Prevention, Pesticides
and Toxic Substances
(7508C)
EPA 738-F-01-008
September 2001
Trichlorfon Facts
EPA has assessed the risks of triehlorfon and reached a decision presented in the "Report on
FQPA Tolerance Reassessment Progress and Interim Risk Management Decision for Trichlorfon" •
(commonly known as a TRED) for this organophosphate (OP) pesticide. With the risk mitigation
measures required, triehlorfon fits within its own "risk cup"; its individual, aggregate risks are within
acceptable levels.
EPA's next step under the Food Quality.
Protection Act (FQPA) is to consider the cumulative
risks of all the OP pesticides, which share a common
mechanism of toxicity. The interim decision on
triehlorfon cannot be considered final until these '
cumulative risks are considered. Further risk
mitigation may be required at that time.
Used primarily on turf, ornamental shrubs and
plants, ornamental bait and fish ponds, and pour-on
treatment for cattle (import only), triehlorfon residues
in food and drinking water are not expected to pose
risk concerns due to mitigation requirements. These
include reducing the number of applications and
rvapplication intervals; and limiting broadcast
treatment on golf courses. With the mitigation,
tnclilorfon fits into its own "risk cup"- it does not pose
risk concerns. '
EPA completed a triehlorfon Reregistration
legibility Decision (RED) before the Food Quality
Protection Act (FQPA) of 1996 was enacted. At
present, only food, drinking water, and residential
uses of triehlorfon must be reevaluated, and
tolerances (legal limits for residues in food) reassessed, to ensure that they meet the new safety
standard required by the FQPA. However, the Agency also reevaluated the occupational risks since
new data was received and recommends mitigation for risk concerns associated with large ornamental
ponds, and application to ornamental plants.
The OP Pilot Public Participation Process
The organophosphates are a group of
related pesticides that affect the functioning of the
nervous system. They are among EPA's highest
priority for review in implementing the Food Quality
Protection Act.
EPA encourages the public to participate
in the review of the OP pesticides. Through a six-
phased pilot public participation process^ the
Agency has released for review and comment its
preliminary and revised scientific risk assessments
for individual OPs. (Please contact the OP Docket,
telephone 703-305-5805, or see EPA's web site,
www.epa.gov/pesticides/op .)
EPA is exchanging information with
stakeholders and the public about the OPs, their
uses, and risks through Technical Briefings,
stakeholder meetings, and other fora. USDA is
coordinating input from growers and other OP
pesticide users. . , . -
Based on current information from
interested stakeholders and the public, EPA is
making interim risk management decisions for'
individual OP pesticides. The Agency will make
final decisions after considering the cumulative
risks of the OP assessment. Please see
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EPA is reviewing the OP pesticides to determine whether they meet current health and safety
standards. Other OPs need decisions about their eligibility for reregistration under FEFRA. OPs with
food, drinking water, and other non-occupational exposures must be reassessed to make sure they
meet the new FFDCA safety standard, brought about by the FQPA.
The trichlorfon TRED was developed through the OP. pilot public participation process, which
increases transparency and maximizes stakeholder involvement in EPA's development of risk
assessments and risk management decisions. EPA worked extensively with affected parties to reach
the decisions presented in this TRED document, which concludes the OP pilot process for trichlorfon.
Uses
An insecticide, trichlorfon is used on golf course turf, home lawns, non-food contact areas of
food and meat processing plants, ornamental shrubs and plants, and ornamental and bait fish
ponds to control insects such as lepidopteran larvae (caterpillars); white grubs, mole crickets,
cattle lice, sod webworms, leaf miners, stink bugs, flies, ants, cockroaches, earwigs, crickets,
diving beetle, water scavenger beetle, water boatman backswimmer, water scorpions, giant
water bugs and pillbugs. Trichlorfon is also used overseas on cattle as a pour-on treatment.
Average domestic usage of trichlorfon is about one million pounds active ingredient (a.i.) per
year. In terms of pounds al, total usage is allocated mainly to lawn care operators (74%) and
golf courses (18%). However, on average, less than 2% of all turf sites are treated with
trichlorfon. Other sites with small usage include landscaping, institutional turf,' turf farms,
nursery/greenhouse, livestock and general farm use. Application rates per acre on these sites
are generally less than 7 pounds a.i. per acre.
Health Effects
Trichlorfon can cause cholinesterase. inhibition in humans; that is, it can overstimulate the
nervous system causing nausea, dizziness, confusion, and at very high exposures (e.g., accidents
or major spills), respiratory paralysis and death.
Risks
Dietary risks from food alone for both acute and chronic 'exposure are not of concern to the
Agency. When surface water is considered as the source of drinking water, dietary risks (footi
and water) exceed the Agency's level of concern for children 1 - 6 years. However, the
Agency believes that mitigation measures required in this TRED decision, and the fact that
trichlorfon has a short half life, will reduce the exposure. Moreover, when the source of
drinking water is groundwater, neither the acute nor the chronic dietary risk exceed the
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Agency's level of concern. Accordingly, aggregate risk with groundwater also does not exceed
Agency concern.
The current occupational risk assessment indicates risk concerns for pond applicators,
applicators using broadcast treatment to golf course fairways, and postapplication worker
concerns following foliar treatments of ornamentals. Risks to workers are of concern if
personal protective equipment is not used, or application methods are not modified.
However, the Agency believes that required mitigation will effectively reduce exposure and risk ,
to a level that is not of concern to the Agency. • ' «
Risk Mitigation
To mitigate risks to handlers and workers:
Prohibit broadcast treatment to golf course fairways; spot treatment to fairways is
permitted.
V Require 7-day application interval (waiting period between treatments) for application
to turf, and limit applications to no more than 3 per calendar year
Require applicators to use a truck-drawn spray rig for ornamental fish and bait ponds
over 1 acre.
• Prohibit foliar application to ornamentals; allow only direct soil spray application to
base of plant.
Next Steps
Numerous opportunities for public comment were offered as this decision was being
developed. The trichlorfon TRED therefore is issued in final (see
www.epa.gov/pesticides/reregistration/statas.ritm or www.epa.gov/pesticides/op ), without a
formal public comment period. The docket remains open, however, and any comments
submitted in the future will be placed in this public docket.
When EPA has considered the cumulative risks for of the OP pesticides, the Agency will issue
its final tolerance reassessment decision for trichlorfon and may require further risk mitigation
measures. Similarly, the Agency may reconsider any part of this interim decision based on new
information which may come to the Agency's attention. For all OPs, tolerances will not be
raised or established until cumulative risks have been considered.
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Agency's level of concern. Accordingly, aggregate risk with groundwater also does not exceed
Agency concern. .
The current occupational risk assessment indicates risk concerns for pond applicators,
applicators using broadcast treatment to golf course fairways, and postapplication worker
concerns following foliar treatments of ornamentals. Risks to workers are of concern if
personal protective equipment is not used, or application methods are not modified.
However, the Agency believes that required mitigation will effectively reduce exposure and risk
to a level that is not of concern to the Agency.
Risk Mitigation
To mitigate risks to handlers and workers:
• Prohibit broadcast treatment to golf course fairways; spot treatment to fairways is
permitted.
Require 7-day application interval (waiting period between treatments) for application
to turf, and limit applications to no more than 3 per calendar year
Require applicators to use a truck-drawn spray rig for ornamental fish and .bait ponds
over 1 acre.
Prohibit foliar application to .ornamentals; allow only direct soil spray application to
base of plant. .
Next Steps
Numerous opportunities for public comment were offered as this decision was being
developed. The trichlorfon TRED therefore is issued in final (see .
www.epa.gov/pesticides/reregistration/status.htm or www.epa.gov/pesticides/op ), without a
formal public comment period. The docket remains open, however, and any comments
submitted in the future will be placed in this public docket.
When EPA has considered the cumulative risks for of the OP pesticides, the Agency will issue
its final tolerance reassessment decision for trichlorfon and may require further risk mitigation
measures. Similarly, the Agency may reconsider any part of this interim decision based on new
information which may come to the Agency's attention. For all OPs, tolerances will not be
raised or established until cumulative risks have been considered.
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