SEPA
United States
Environmental Protection
Agency
EPA- 820-F-13-019
August 2013
Human Health Benchmarks for Pesticides -
2013 Update
Summary
EPA has updated its Human Health Benchmarks
for Pesticides (HHBPs) in drinking water to
reflect the latest scientific information. HHBPs
are levels of certain pesticides in water at or
below which adverse health effects are not
anticipated from one-day or lifetime exposures.
A total of 363 HHBPs are now available for
pesticides that are currently registered for use on
food crops. The benchmarks are for pesticides
for which the agency has not issued a drinking
water health advisory or set an enforceable
federal drinking water standard.
EPA first developed the human health
benchmarks for pesticides in 2012 to enable
states, tribes, water systems, public and other
stakeholders to better determine whether the
detection of a pesticide in drinking water or
source waters for drinking water may indicate a
potential health risk. The human health
benchmarks for pesticides were developed with
the same methods used by the Agency to
calculate health advisories for drinking water
and are based on data that were peer-reviewed in
EPA's pesticide registration process.
In this update, EPA is adding 11 new
benchmarks for a total of 363 HHBPs. In
addition, EPA has revised 10 of the HHBPs
published in 2012 to reflect new scientific
information. This update also includes cancer
effect benchmarks for 40 pesticides. It should be
noted that the data supporting these benchmarks
have been previously published in EPA pesticide
risk assessments available on the web at
http://www.epa. gov/pesticides/hhbp.
Background
In March 2010 EPA announced a drinking
water strategy that outlined four principles to
expand public health protection. One of these
principles is to use the authority of multiple
statutes to more effectively protect drinking
water, by sharing data collected under different
statutes. EPA derived the HHBPs by applying
the health effects data from pesticide
registrations under the Federal Insecticide,
Fungicide, and Rodenticide Act and tolerances
under the Federal Food, Drug, and Cosmetic Act
as amended by the Food Quality Protection Act,
to the typical methods used for developing
drinking water health advisories under the Safe
Drinking Water Act.
EPA is providing the HHBPs for informational
purposes for use by states, water systems and the
public to help understand monitoring data for
pesticides that have no drinking water standards
or health advisories. Drinking water systems can
also use them as reference values to respond to
customer inquiries if pesticides are detected
through monitoring.
Development of Human Health Benchmarks
for Pesticides in Drinking Water
The 2013 HHBPs were derived for non-cancer
and cancer health endpoints. They include
mainly active ingredients at this time, and thus
inert compounds used in pesticide formulations
are not included.
For non-cancer effects, the HHBPs were
established for acute and chronic effects. EPA
used the acute and chronic reference doses
(RfDs) established for the most sensitive life
stage/population. EPA applied standard drinking
water exposure assumptions that are used in
calculating health advisories.
For the acute HHBPs, the entire exposure is
assumed to occur from drinking water
For the chronic HHBPs, EPA applied a default
relative drinking water source contribution of 20
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percent, assuming additional exposure may arise estimation, contact Brenda May at
from other sources, like food, air or dermal mav.brenda@epa.gov.
contact.
The acute and chronic HHBPs do not include
safety factors in the RfD that are attributed to
residual uncertainty with regard to exposure or
pre/post natal toxicity as mandated by the Food
Quality Protection Act. These safety factors are
not part of the standard methodology used for
calculating health advisories under the Safe
Drinking Water Act.
For cancer effects
Cancer effects benchmarks were calculated for
40 pesticides using cancer slope factors,
standard drinking water exposure assumptions,
and a risk range of one in one-million to one in
ten-thousand. A cancer slope factor is the
toxicity value for evaluating the probability of
an individual developing cancer from exposure
to contaminant levels over a lifetime.
Most pesticides that have cancer effects do not
have cancer slope factors (e.g., threshold type
carcinogens or those chemicals for which a
mode of action has been established and
accepted by the Agency). In cases where a
cancer slope factor is not calculated, the chronic
(non-cancer) HHBPs are considered protective
of cancer health effects.
How to View the HHBPs and Supporting
Information
To view the table of HHBPs and supporting
information, online go to:
http://www.epa.gov/pesticides/hhbp.
Current EPA health advisories and enforceable
drinking water standards for other pesticides can
be viewed at:
http://water.epa.gov/drink/standards/hascience.cf
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For More Information
For information regarding derivation of
HHBPs, contact Santhini Ramasamy at
ramasamv.santhini@epa.gov.
For information regarding the documentation for
deriving the reference doses or cancer risk
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