The primary science policy issue concerning NDs is what value the EPA’s Office of
Pesticide Programs (OPP) should assign to them when estimating exposure and risk
from pesticides in food. The reason this is an important issue stems from the require-
ments that the FQPA imposes on the EPA. The OPP’s claimed objective is to make
exposure and risk assessment as accurate and realistic as possible while not underesti-
mating exposure or risk, so that all people, including infants and children, are fully
protected.^29Risk of Exposure CalculationPotential exposure to a chemical in a specific food is assessed by multiplying the
residue concentrations in food by the amount of food consumed. Potential dietary ex-
posure to a chemical is assessed by tabulating residue intakes from all foods.
Different assumptions regarding residue concentrations in food may be used to
assess exposure. A worst-case exposure scenario may be calculated using tolerance lev-
els for pesticides in food. This exposure assessment is the theoretical maximum resi-
due contribution. Exposure may also be calculated using anticipated residue levels.Pesticide Inerts TreatmentThe EPA is required to set tolerances or grant exemptions based on the FQPA
safety standard for all ingredients in a pesticide product for use on food. The law
stated that inert ingredients used on food are ‘‘pesticide chemicals’’ on the same basis
as active ingredients. Inerts are approved under the same safety standard of ‘‘reasona-
ble certainty of no harm’’ from dietary exposures and all other exposures, where there
is reliable information, for all people, including infants and children. Inerts are now
referred to as ‘‘other ingredients.’’
For that matter, approvals have been very slow and practically nonexistent for
many food-use chemicals. For these so-called other ingredients the EPA has set one
tolerance and exempted seventeen from tolerance requirements based on the FQPA’s
standard.^30Storage and Processing ImpactThere is a large gap between consumer and scientific perceptions on the risks that
pesticide residues in food pose to human health relative to other dietary risks. One
cause of this misconception has been the emphasis placed on ‘‘worst-case’’ evaluations
and extrapolations of available data, for example, assuming that all crops are treated
with pesticides and that the resulting residues in food are at maximum permitted
levels.^31
Controls on pesticide residues in crops are generally based on MRLs that are set
using field trial data to arrive at the highest expected pesticide residue levels. Primary
residue studies on food crops are mainly carried out on samples that are deeply frozen
prior to analysis and that receive minimal post-harvest handling, except possibly
minor trimming. Although MRLs are a credible and useful means of enforcing88 | Pesticides