Maximum pesticide residue levels

Pestieide tolerances are not based solely on safety, but rather are set to represent the maximum expected residue levels of a pesticide on a commodity as a result of the legal application of the pesticide. The maximum expected levels are derived from the results of controlled field studies conducted by the pesticide manufacturer, in which application conditions are chosen to provide the highest level of residue. Conditions include applying the pesticide at the maximum allowable rate, making the maximum number of applications per growing season, and harvesting the food after the minimum anticipated interval between application and harvest. 

The ability to use probabilistic approaches to assess dietary pesticide exposure has also changed much of the emphasis of pesticide risk assessment practices from assessing long-term (chronic) exposure to short-term (acute) exposure. Deterministic approaches worked well with chronic assessments since the day-to-day variability in food consumption patterns and the variability of pesticide residue levels tended to average out over the course of a 70-year exposure period. Deterministic approaches have also often been used in the assessment of acute dietary risk by assuming an upper percentile level of food consumption and the maximum detected or allowable level of residue. The point estimate determined in this manner is then compared with the RfD to determine the acceptability of exposure under the specified conditions. 

Despite the fact that the average consumption of pesticides are still low in India, (05kg ha-1) against 6.6 and 12kg ha-1 in Korea and Japan, respectively, there has been widespread contamination of food commodities with pesticide residues, basically due to their non-judicious use. In a recent review Gupta (2004) has stated that in India, 51% of food commodities are contaminated with pesticide residues and out of these, 20% have residues above the maximum permissible residue levels on a worldwide basis. 

Subdivision O guidelines for residue chemistry data were originally pubHshed by the EPA in 1982. These have been supplemented to improve the rate of acceptance by EPA reviewers of the many reports submitted by registrants in support of tolerances for pesticides in foods. The residue chemistry studies most frequently rejected include metaboHsm in plants, food processing (qv) studies, and studies on storage stabHity of residues in field samples (57). AH tolerances (maximum residue levels) estabHshed under FIFRA are Hsted in 40 CFR under Sections 180 for individual pesticides in/on raw agricultural commodities, 180 for exemptions from tolerances, 185 for processed foods, and 186 for animal feeds. 

When illegal residues have been found in monitoring studies conducted by the FDA or USD A, the reason has often been that no U.S. tolerance had been requested for that particular pesticide in that specific crop. For example, an imported crop would be deemed to be adulterated and would be seized at the port of entry into the United States if found to contain a pesticide residue in the absence of a tolerance in that crop. This is so even if tolerances have been set for the same pesticide in several crops grown in the United States and the pesticide had been used to control a pest that does not exist in the United States. Furthermore, an international maximum residue level (MRL) might already have been estabUshed for that pesticide—crop combination under the Codex system of standards for food of importance in international trade. The U.S. GAO issued two reports on food safety and pesticides in 1991 (89,90). 

Regulation on mles for provisions of Directive 86/362/EEC and Directive 90/642/EEC on the maximum levels of pesticide residues... 

A subsequent comparison of these ionization techniques for the study of another eight pesticides, this time including three of the five of interest [28], i.e. carbendazim, thiabendazole and thiophanate methyl, showed that ESI gave enough sensitivity to allow reliable determination of the pesticides at concentrations below their respective maximum residue levels. 

Methyl parathion is approved only for use on crops. The maximum amount of methyl parathion residue allowed by the Food and Drug Administration (FDA) and EPA on crops used as food is 0.1-1 ppm. The FDA has monitored the food supply for pesticides for a number of years. FDA purchases many kinds of foods through Market Basket Surveys and analyzes them for residue levels of pesticides. These FDA studies allow scientists to estimate the daily intake of pesticides. Generally, the FDA monitoring studies conclude that the U.S. food supply contains only very small amounts of pesticides that are not a concern. However, there have been some reports of the illegal use of methyl parathion inside homes. For more information, see Section 1.7 and Chapter 6. 

One FDA study (Roy et al. 1997) determined the levels of pesticide residues in rice and apples. Of the 769 domestic apples analyzed, methyl parathion was found in 72 samples at a maximum concentration of 0.15 ppm. Of the 1,062 imported apples analyzed, methyl parathion was found in 4 samples at a... 

CEC. 1976. Council directive of 23 November 1976 relating to the fixing of maximum levels for pesticide residues in and on fruit and vegetables. Off J Euro Comm L340 26-31. 

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. 

While all nations of the world possess the sovereign right to establish their own acceptable levels for pesticide residues in foods, many lack the resources to develop their own regulatory programs and instead rely upon a set of international standards developed by the Codex Alimentarius Commission, frequently referred to as Codex. The Codex international standards are termed maximum residue limits (MRLs) and, like U.S. tolerances, are established primarily as enforcement tools for determining whether pesticide applications are made according to established directions. While many countries have adopted Codex MRLs, others, such as the U.S. and several Asian countries, rely on their own standards. Thus, there is no uniformity among the world with respect to allowable levels of pesticides on foods. A pesticide-commodity... 

Until 1994 the EPA regulated pesticides proposed for use on food crops under certain sections of the Food, Drug, and Cosmetics Act. Carcinogenic pesticides were subject to the Delaney clause, and were thus prohibited. The use of a non-carcinogenic pesticide was allowed if its manufacturer provided data sufficient to establish an RfD, and information on expected food residue levels sufficient to document that the RfD would not be exceeded when people consumed food containing residues of the pesticide. The tool for determining compliance with this criterion is called a tolerance, and it is expressed as the maximum amount of a pesticide that can be present in a given amount of food, if the RfD is not to be exceeded. 

The main FAO/WHO expert bodies include the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the Joint FAO/WHO Meetings on Pesticide Residues (JMPR), and the Joint FAO/ WHO Expert Meetings on Microbiological Risk Assessment (JEMRA). Codex Alimentarius provides lists of MRLs for pesticides and veterinary drugs, and maximum levels for food additives. 

The use of pesticides in agriculture has obvious advantages, such as an increase in the quantity and quality of food crops. Nevertheless, pesticides are toxic substances, and their residues can pose a risk to man and environment. Therefore, pesticide residues in food are regulated at the international and national levels according to the toxicity of the compound and the human intake of a particular crop. The acute oral toxicity for rats and the maximum residue levels (MRLs) of carbamate and urea pesticides are listed in Tables 1 and 2. 

To protect consumers health, many countries have restricted the use of pesticides by establishing legal directives on maximum residue levels (MRLs) to control their levels in food (28). These MRLs sometimes cause conflicts, because residue levels acceptable in one country may be unacceptable in others. This problem has revealed the need to harmonize the different MRLs, which have been dealt with mainly by two international organizations, the European Union (EU) at the European Level, and the Codex Alimentarius Commision of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) (28,29). 

FAO, Submission and Evaluation of Pesticide Residues Data for the Estimation of Maximum Residue Levels in Food and Feed, 1st ed., FAO, Rome, 2002. 

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