Dietary Risk Index Acronyms and Keywords
Action Level – The Food and Drug Administration has set “action levels” for several obsolete, but persistent pesticides that are still found in soil, certain crops, and animal fats. Action levels are only set for pesticides lacking any tolerances. Action levels serve a comparable purpose to tolerances, and establish a benchmark value used in assessing dietary risks.
AT – The “Action Threshold” for a given food-pesticide combination plays a key role in determining whether a pesticide residue found in organic food is acceptable, and what certifiers and organic farmers must do when a residue is found. The AT is equal to 5% of the applicable U.S. Environmental Protection Agency (EPA) tolerance. The AT is set forth in the National Organic Program (NOP) rule, and is embodied in the original legislation establishing the NOP. When residues of a pesticide not permitted for use on certified organic food are found above the AT, the food should not be sold as organic. It may be sold as conventional, as long as the residue found did not exceed the applicable tolerance. Certified organic food with a residue of a prohibited pesticide below 5% of the applicable tolerance may be sold as organic, but the certifier is responsible for working with the grower-packer-shipper to identify the source of the residue and eliminate it in the future. The AT does not apply to pesticides approved for use by organic farmers.
cRfC – The “chronic Reference Concentration” is used in calculating both forms of the DRI. It is a measure of the level of residues that can be in a serving of a given food without exposing a person of known weight to a dose of the pesticide that exceeds EPA’s “level of concern,” as quantified in the pesticide’s chronic Reference Dose or chronic Population Adjusted Dose.
cRfD – The “chronic Reference Dose” is a key, pesticide-specific toxicological parameter set by the EPA in order to evaluate whether human exposures to pesticides are acceptable, or exceed the agency’s “level of concern.” A cRfD is calculated by dividing the EPA-determined “No Observable Adverse Effect Level” (NOAEL) by a safety factor, which is typically 100. Based on its review of all toxicological studies submitted in support of the registration of a pesticide, the EPA identifies the statistically significant adverse effect that occurs at the lowest dose level. The NOAEL is the next dose level just below the lowest level triggering an adverse health impact. The cRfD is measured in milligrams of pesticides ingested per kilogram of bodyweight per day. It is used to draw the line between acceptable residues and exposures, and residues/exposures that exceed the EPA’s “level of concern.”
cPAD – The “chronic Population Adjusted Dose” is the cRfD divided by any additional safety factor imposed by the EPA as a result of the implementation of the Food Quality Protection Act (FQPA). In most cases, FQPA-driven added safety factors were 10-fold, although some were adjusted downward to 5-fold or 3-fold.
DRI – “Dietary Risk Index,” a method to quantify the relative risks stemming from pesticide residues in food or beverages, based on the mean level of residues reported by PDP in a food, average serving sizes of the food, and chronic Reference Doses or chronic Population Adjusted Dose (cPAD) set by the Environmental Protection Agency (EPA). See The Dietary Risk Index for more details.
DRI-M – The “Dietary Risk Index – Mean” is a ratio equal to the mean level of residues of a specific pesticide found in a given food, divided by a pesticide’s chronic Reference Concentration (cRfC). This form of the DRI is appropriate for comparing pesticide-related risk levels in a given food known to contain more than one pesticide, or for comparing risk levels across pesticide-food combinations. It does not take into account how often a given food is eaten, nor the frequency of residues across all tested samples. See The Dietary Risk Index for more explanation.
FS-DRI – The “Food Supply (FS) Dietary Risk Index” value for a given pesticide-food combination is the DRI-M multiplied by the percent of samples tested that contained the pesticide. Unlike the DRI-M, the FS-DRI takes into account how frequently a residue appears in a tested food, and hence is the appropriate metric when assessing relative pesticide risk levels and trends in the food supply. See The Dietary Risk Index for more details.
FQPA – The “Food Quality Protection Act” was passed in 1996 and dramatically changed the basis for evaluating pesticide safety. It directed the EPA to impose an added safety factor up to 10-fold to take into account the unique vulnerability of infants and children following pre-natal or post-natal pesticide exposures, unless the EPA determined that the existing cRfD of a pesticide was fully protective and based on complete and sound toxicology and exposure data. See Impacts of the 1996 Food Quality Protection Act on Relative Risks for more on the FQPA.
Mean of Positives – For a given food-pesticide-year combination tested by the PDP, all residue values greater than zero are selected, and then the arithmetic mean is calculated. The mean residue level in all positive samples is the numerator in the DRI ratio. It serves as an indicator of the average level of residues in a given food. For most food-pesticide combinations, the mean of the positive samples understates 95th percentile and 99th percentile residue levels by 5- to 7-fold.
NOP – The USDA’s Agricultural Marketing Service administers the National Organic Program. The NOP established the rules governing organic certification, oversees the process of adding materials to the national list of approved substances for use in organic farming, and enforces compliance with the national rule.
UREC – Unavoidable Residual Environmental Contamination is a term adopted by the National Organic Standards Board (NOSB) and the National Organic Program (NOP) in drafting the provisions within the NOP rule governing pesticide residues in organic food. (For details see NOP policies governing residues in food). UREC levels of pesticides can be found in organic samples as a result of carryover in the soil, contamination of irrigation supplies, pesticide drift or volatilization, or pesticide movement in packing houses and storage facilities. In general, organic farmers have little control over UREC-level residues.
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