Chlorpyrifos (Dursban®, Lorsban®) Dietary Exposure Assessment
Abstract
Analyses of potential dietary exposure to chlorpyrifos residues have been conducted by the Department of Pesticide Regulation (DPR). The acute and chronic dietary exposure to primary residues on raw agricultural commodities (RACs) and secondary residues, which result from residues on animal feeds, have been assessed under the provisions of AB 2161 (Bronzan). The potential exposure to residues in RACs as consumed by members of specific population subgroups, including infants and small children, and the attendant margins of safety have been assessed.
DPR concludes the margins of safety, based on cholinergic signs in humans, for potential acute dietary exposure to chlorpyrifos residues on labelled-use commodities are adequate. Margins of safety, based on inhibition of brain cholinesterase activity in rats and dogs, for potential chronic dietary exposure to chlorpyrifos residues are also adequate.
A tolerance is the maximum, legal amount of a pesticide residue that is allowed on a raw or processed agricultural commodity, or in an animal tissue used for human consumption. Under AB 2161, DPR has calculated the margins of safety associated with potential acute dietary exposure to chlorpyrifos on each RAC at tolerance. The tolerance for chlorpyrifos on apples provides adequate margins of safety for all population subgroups with the possible exception of non-nursing infants, less than the age of 1. However, the tolerance is for whole apples. Yet non-nursing infants consume apples predominantly as processed foods such as apple sauce or juice. Thus, the actual margin of safety, based on tolerance, is considered adequate. All other tolerances for chlorpyrifos on label-approved commodities provide adequate margins of safety for potential acute dietary exposure for all population subgroups.