Pesticide residues standards

Pesticide Residues Standards or Standards for Withholding Registration of Pesticides on Crop Residues ... 

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). 

Egan H. 1969. lUPAC Commission on the development, improvement, and standardization of methods of pesticide residue analysis. J AOAC 52 306-309. 

January 1992, two working groups have been dealing with analytical methods for the determination of pesticide residues WG 3 Pesticides and PCBs in Fatty Foods and WG 4 Pesticides in Nonfatty Foods . So far analytical methods for 47 pesticides and their metabolites in fatty food and methods for more than 200 pesticides in nonfatty foods have been published in several standards (Table 6). 

Komit6 for Levnedsmidler (NMKL)]. The standard presents a universal validation approach for chemical analytical methods in the food sector. This includes methods for the main constituents and also for trace components. Therefore, the NMKL procedure focuses on primary validation parameters, such as specificity, calibration, trueness, precision, LOD or LOQ and does not refer to special requirements of pesticide residue analysis. 

Different sample materials often need some adjustment of pesticide residue methods. The insufficient consideration of matrices in thcNKML method validation protocol may be a tribute to the wide scope of this standard. 

In summary, official German analytical methods for pesticide residues are always validated in several laboratories. These inter-laboratory studies avoid the acceptance of methods which cannot readily be reproduced in further laboratories and they do improve the ruggedness of analytical procedures applied. The recently introduced calibration with standards in matrix improves the trueness of the reported recovery data. Other aspects of validation (sample processing, analyte stability, extraction efficiency) are not considered. 

L. Alder, G. Kempe, and P. Baumann, Need of Matrix Matched Standards-Conclusion from a German Ring Test, Presented at 3rd European Pesticide Residue Workshop, York, UK, July 3-5, 2000. 

Law and Goerlitz in 1970 reported the effective removal of co-extractives from water using microcolumns of these three adsorbents for the analysis of chlorinated pesticides. The development of polystyrene resins such as XAD increased the ability to concentrate pesticide residues from water. Large volumes of sample water could be passed through an XAD resin and the pesticide would adsorb on the resin. Elution of the pesticide by an organic solvent such as methanol and subsequent cleanup by the adsorbent materials became the industry standard. 

Multi-residue Method S19 of the DFG Manual,including Cieanup Procedure Xll-6 (gel-chromatographic cleanup), has been used successfully in many laboratories because of its broad applicability for the gas-chromatographic determination of pesticide residues in foodstuffs. DFG method S19 is also included in the respective European Standards. Subsequently, a modification of the extraction and partition step has been implemented. The modified method requires less experimental effort and eliminates the use of dichloromethane, which is an undesirable solvent for toxicological and ecological reasons. As the results from validation studies demonstrate,... 

Tolerances for pesticide residue and/or standard withholding registration of neonicotinoids in Japan are shown in Table 1. 

Pesticide Residue Committee (2001). Annual Report of the Pesticide Residue Committee 2001. United Kingdom Food Standards Agency. 

Consider the analysis of plant material for a pesticide residue by GC. Two grams of the material is chopped up and placed in a Soxhlet extractor (Chapter 11) and the pesticide quantitatively extracted into an appropriate solvent. Following this, the solvent is evaporated to near dryness and the residue is diluted to volume in a 25-mL flask. Then 2.5 pL of this solution and standards is injected in a GC with the following results ... 

Prom the audience in a different regard, "Different analysts are producing different data sets which are pooled in standard databases. For example, the the database of constituents and nutrients in food is one the Department of Agriculture maintains. Different people submit various analytical levels of these quantities along with various pollutants like pesticide residues and that sort of thing. The question is how can these databases identify method bias which they do not now do How would you identify the data elements that should exist in pooled data bases that would allow bias adjustment to be made " You readers must search for that answer. 

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. 

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... 

Reference doses for pesticides are used in just this way to establish standards (called tolerances) for pesticide residues in food. Similarly, ADIs, derived for food additives, are used to establish allowable limits on amounts that can be added to foods. Data on rates of food intake are necessary for pesticides and food additives, in the way that water intake rates were used in the example given above. 

A farmer, however, disposing of waste pesticides which are hazardous wastes, from his own use, is not required to comply with the RCRA notification or management standards provided he triple rinses each emptied pesticide container and disposes of the pesticide residues on his own farm in a manner consistent with the disposal instructions on the pesticide label. This exemption from the RCRA management controls does not apply, however, to commercial pesticide applicators. 

Toxicological evaluations of food additives and of contaminants, naturally occurring toxicants and residues of veterinary drugs in food produced by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), and of pesticide residues in food by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) are used by the Codex Alimentarius Commission and national governments to set international food standards and safe levels for protection of the consumer. 

System Suitability System suitability refers to the validation of all components of an analysis system taken as a unit, a "system." For example, the analysis of an environmental water for pesticide residue involves a "method," which includes sampling (must represent the water in question), sample handling (e.g., what container is appropriate), sample preparation (perhaps an extraction process that includes the glassware, technique, timing, etc.), standards preparation (pipets, flasks, technique, etc.), injection technique, the instrument, and data handling (computer hardware and soft-... 

An additional mechanism of identification, again dependent on standards and on reasonable prior knowledge of likely identities, has been reported by Beroza and Bowman (15-18). The technique involves a measurement of the distribution of the unknown component between two nonmiscible liquids. This work was primarily directed toward pesticide residue analysis. Dealing with pesticide residue analyses, it is accepted that sample processing will ultimately provide a sample for measurement in hexane or isooctane solution. Occasionally this may be in another solvent. 

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