Tolerance levels, pesticide

U.S. Environmental Protection Agency (USEPA), pesticide tolerance levels and, 14 337... 

Cosmetic Standards. Over the last two decades, the U.S. Food and Drug Administration (FDA) has been lowering the tolerance levels for Insects and insect parts allowed in and on fresh and processed foods (14). Concurrently consumers have sought "more perfect," pest-free produce. To achieve this, farmers have Increased the quantities of pesticide they applied to crops. Although the presence of small amounts of insect parts in such products as catsup and apple sauce, or blemishes on oranges pose no health risk, these stringent standards have stood for many years. 

The FFDCA governs the establishment of pesticide tolerance for food and feed products. A tolerance is the maximum level of pesticide residues allowed in or on human food and animal feed. ... 

When the normal use of a pesticide on a food crop may pose the potential to leave a food residue, the EPA establishes a tolerance. The tolerance represents the maximum level of a pesticide residue allowed on the food crop. Tolerances are pesticide and crop specific different crops may have different tolerance levels for a particular pesticide, while a particular crop may have different tolerance levels for the different pesticides that may be used on it. 

Pesticide residues will be considered illegal when pesticides are detected at levels that exceed the tolerance level, or when residues of a pesticide are detected, at any level, on a commodity for which a tolerance has not been established. Illegal residues should not be confused with unsafe residues, however, since pesticide tolerances are most appropriately viewed as enforcement tools rather than as safety standards. 

It is critical to realize that pesticide tolerances themselves are not safety standards but rather enforcement tools for indicating whether pesticides have been applied according to directions. Violative residues result when residue levels exceed the tolerance due to the misapplication of a pesticide, or when residues at any level are found on a commodity for which a tolerance was not established (which could result from product misuse). While a few isolated cases of violative residues have resulted in human harm, the vast majority of violative residues are of little or no toxicological consequence. 

In the United States, food safety is an important responsibility not only of the Food and Drug Administration (FDA), but also of the U.S. Department of Agriculture (USDA), the Environmental Protection Agency (EPA), and other agencies at the federal, state, and local levels. The EPA registers or approves the use of pesticides and establishes a tolerance level if the use of a pesticide may lead to residues in food (30). 

The exposure of humans to pesticides from residues In food is dependent both on the quantity of a food consumed and the residue levels therein. The Agency has traditionally used a simplified method of estimating chronic exposure to pesticide residues that was originally developed by the Food and Drug Administration. This exposure method is based on the assumptions of tolerance level residues in food and national average food consumption per capita. 

In 1998, PDP collected samples of apple juice, cantaloupe, grape juice, green beans, orange juice, pears, spinach, strawberries, sweet potatoes, tomatoes, winter squash, com symp, milk, and soybeans. A total of 8500 samples were collected. Most of these were from fmits and vegetables (7017) with lower numbers of samples collected for whole milk (595), soybeans (590) and com symp (298). The majority of samples (84 percent) was of domestic origin. Overall, 45 percent of the samples contained no detectable residue while 26 percent contained one residue and 29 percent contained more than one residue. Residues exceeding the tolerance level were detected on 0.15 percent of the samples. In another 3.7 percent of the samples, residues of pesticides were detected on commodities for which no tolerances of the pesticides were established (USDA, 2000). 

Tolerances are normally required in cases where the legal use of a pesticide might result in residues on a food or feed crop. Tolerances are specific to commodity/pesticide combinations the same pesticide may have different tolerance levels established for different commodities while the same commodity may have several different tolerance levels established for different pesticides. 

Tolerances are primarily established to represent the maximum residues anticipated from the legal use of the pesticide on the commodity. The maximum residue levels are determined from the results of controlled field studies performed by the pesticide manufacturer in a variety of geographical regions. The manufacturer performs the studies under conditions that would likely yield the maximum residue levels such as applying the pesticide at the maximum recommended rate for the maximum number of applications anticipated and harvesting the commodity at the minimum expected preharvest interval. The highest residue levels detected under these worst-case application scenarios are identified and the manufacturer petitions the EPA to establish the tolerance levels at or slightly above the maximum residues encountered. 

It is correct to note that the specific tolerance levels requested by the manufacturer are determined solely on the basis of agricultural practices and not upon potential human health considerations. As such, tolerances represent enforcement tools to determine whether pesticide applications were made in accordance with the law but should not be considered as safety standards. In the case where a pesticide is used properly, the resulting residue level should be below the tolerance level. Residues detected in excess of the established tolerance are likely encountered only in cases where applications are not made in accordance with the legal directions. Results obtained from federal and state monitoring programs demonstrate that the incidence of residues detected in excess of tolerances is very low and suggest that most pesticide applications are made legally. 

Maximum residue level (MRL) Comparable to a U.S. tolerance level, the maximum residue level is the enforceable limit on food pesticide levels in some countries. Levels are set by the Codex Alimentarius Commission, a United Nations agency managed and funded jointly by the World Health Organization and the Food and Agriculture Organization. 

We need to develop a certification system for all inputs, products and processes involved in a food system. Certification of tolerance levels of pesticides in all stages of a food... 

The need exists to expand the repertoire of tools available for weed management systems. What little we know of the molecular target sites of natural phytotoxins indicates that they are inhibitors of a broad array of enzymes and other molecular targets that have not been the focus of herbicide discovery efforts [1]. At present, commercially available herbicides target a relatively limited number of enzymes and metabolic pathways. The discovery of new target sites is a growing emphasis of pesticide companies, especially since the U.S. Food Quality Protection Act has combined food tolerance levels of pesticides with the same molecular target sites. 

Pesticides may stick to treated surfaces, such as food or feed products that are to be sold. To protect consumers, there are legal limits (tolerances) for how much pesticide residue may safely remain on crops or animal products that are sold for food or feed. Products that exceed these tolerances are illegal and cannot be sold. Crops and animal products will not be over tolerance levels if the pesticides are applied as directed on the product labeling. Illegal pesticide residues levels usually result when ... 

EPA. 1986a. EPA approves Unocal Corp pesticide petition (PP 6C3350) to establish temporal tolerance levels for carbon disulfide in/on grapefruit, grapes, oranges, and potatoes at 0.1 ppm resulting from nematicide sodium tetrathiocarbonate. Federal Register 51 23151. 

The U.S. EPA Office of Pesticide Programs (7) reviewed and evaluated the toxicological data base submitted by Monsanto in support of a petition for tolerance levels for alachlor in or on raw agricultural commodities. Data considered in support of the petition and summarized in the Federal Register, included ... 

Now I hope you see why I believe that it is criminal to sound an alarm when a pesticide residue is detected on produce at 100 to 1000 times below the tolerance. The tolerance is related to a safety threshold, not a toxic one. This misuse of data totally ignores the entire risk assessment process that is appropriately conservative and protective of human health. What is even more ironic is that the very chemicals that the public is made to fear in food at these below-tolerance levels are often used by the same individuals in household and garden pesticide products at much higher doses. These are generally proved to be safe for most individuals, making worrying about food concentrations millions of times lower a totally worthless experience that detracts us from more serious concerns. 

The ADI or RfD is the measure of the hazard the chemical has for humans. It is that level of chemical that is deemed to be safe for daily lifetime human consumption. For safe residue levels to be set, exposure must now be determined. Every regulatory agency also has a method to accomplish this. The problem is determining how much food a person must eat to achieve this ADI. There have been numerous studies that have assessed the patterns of our food consumption to get at what is an average diet in our country. In cases such as milk, where the food may comprise the infant s entire diet, consumption is often overestimated. The presentation of these numbers is beyond the scope of this appendix since my purpose is only to illustrate the process that determines a pesticide tolerance in the field that is the trip wire for concern. This number is the concentration on the product itself, which based on patterns of food consumption, will determine the amount of daily consumption of the chemical. 

---