Pesticide residue findings by the Luke method in domestic and imported foods and animal feeds for fiscal years 1982-1986

Nearly 20,000 samples of food and feed commodities were analyzed for pesticide residues by the U.S. Food and Drug Administration Los Angeles District Laboratory during the 5-year study period 1981-1986. The resultant data base has been summarized to provide separate residue information for domestic and imported samples. The overall violation rates for domestic and imported samples collected on a surveillance basis were 3.0 and 2.6%, respectively. For domestic and imported samples collected on a compliance basis, the overall violation rates were 19.7 and 17.5%, respectively.     

Refinements in acute dietary exposure assessments for chlorpyrifos.

Food pesticide residue data are used by the U.S. Environmental Protection Agency (EPA) to determine potential dietary risk from chronic and acute exposures. An acute dietary risk assessment determines the pesticide exposure resulting from a single-day consumption of food, and uses stepwise refinement of residue estimates to better judge actual exposures. All exposure refinements use estimates of the fraction of crops treated and food residues measured increasingly closer to the point of actual food consumption, without changes in the pesticide uses. Exposure distributions at all levels of data refinement were extremely right skewed. At the highest level evaluated, estimated exposures at the 99.9th percentile were 0.00087 mg/kgBW/day compared to 0.2648 mg/kgBW/day at the tolerance level for children 1-6 years, theoretically the highest-exposed population sub-group. The estimated exposure at the 99.9th percentile of the U.S. population was approximately twice the exposure at the 99th percentile and 33 times the exposure at the 90th percentile. This evaluation showed the calculated exposure at the highest tier of assessment was 300 times lower than the tolerance level assessment for children 1-6 years at the 99.9th percentile. Reduction in exposure estimates between these tiers was due to a combination of the following factors: food residue measurements in a specially designed market-basket study, government-sponsored monitoring data, probabilistic methodologies, market share information, and food processing data. This case study demonstrates that an improved understanding of the uncertainties of acute dietary exposure from pesticides is possible by using well-established statistical tools and applying them to comprehensive exposure information, including residue monitoring data, consumption data, and pesticide use information.     

Food and Drug Administration pesticide residue monitoring of foods: 1978-1982

Pesticide residues in foods are reported for the 5-year period 1978-1982 [fiscal years (FY) 78-82]. Results were compiled from the 2 complementary elements that comprise the Food and Drug Administration's (FDA) program for monitoring pesticide residues in foods. Under regulatory monitoring, which focuses on residues in raw agricultural commodities, a total of 49,877 samples (30,361 domestic and 19,516 import) that included fresh fruits and vegetables, grains, milk and dairy products, seafoods, and a variety of processed foods were analyzed. No residues were found in about 55 and 44% of the domestic and import samples, respectively. About 3% of the domestic and 7% of the import samples were classed as violative. Data from the Total Diet Study, which is conducted to determine dietary intakes of a variety of chemicals, showed that residues of 42 pesticides were found in 1044 composites of table-ready foods. Results of FDA's monitoring for FY78-82 demonstrate that pesticide residue levels in the U.S. food supply were generally well below regulatory limits, and dietary intakes were manyfold lower than the Acceptable Daily Intakes established by international agencies.     

Tolerance setting process in the U.S. Environmental Protection Agency

The U.S. Environmental Protection Agency (EPA) is responsible for setting tolerances for pesticide residues in food, under the authority of the Federal Food, Drug, and Cosmetic Act. The residue chemistry data required to set tolerances include metabolism in plants and animals, analytical methods, magnitude of the residue, and concentration in processed foods. A key aspect of tolerance-setting procedures is the identity of the residue in the matrix of concern; without knowledge of the chemical moieties that occur as residues, it is impossible to develop suitable methods or generate meaningful residue data. For new chemicals, EPA carries out a single-laboratory validation of the analytical method needed to generate residue data and to enforce tolerances. Tolerance enforcement methods need to be rapid and inexpensive and to use commercially available equipment and reagents. Methods are more complex for many newer pesticides, which are polar compounds that leave low levels of residue. EPA now requires that the registrants of older pesticides, for which methods are not acceptable by today's standards, must develop better methods.     

Food and Drug Administration pesticide residue monitoring of foods: 1983-1986

Pesticide residues in foods are reported for the 4-year period 1982-1986 [fiscal years (FY) 83-86]. Results were summarized from the 2 complementary approaches that make up the Food and Drug Administration's (FDA) pesticide residue monitoring program. Under regulatory monitoring, which focuses on residues in raw agricultural commodities, a total of 49,055 samples (27,700 domestic and 21,355 import) that included fresh fruits and vegetables, grains and grain products, milk and dairy products, seafoods, and a variety of processed foods were analyzed. No residues were found in 60 and 48% of the domestic and import samples, respectively, compared with 55 and 44% in FY78-82. About 3% of the domestic and 5% of the import samples were violative. In FY78-82, about 3 and 7% were violative, respectively. The other FDA monitoring approach, the Total Diet Study, was revised in April 1982 to expand coverage of age/sex groups, use updated diets, and provide for analysis of individual foods. Results from monitoring under this modified approach and from regulatory monitoring continued to demonstrate that pesticide residues in the U.S. food supply were well below regulatory limits, and dietary intakes were many times lower than the Acceptable Daily Intakes established by international agencies.     

The FDA pesticides program: goals and new approaches

The U.S. Food and Drug Administration (FDA) has carried out a large-scale monitoring program for pesticide residues in foods since the 1960s. The program has evolved continuously as evidenced by a number of recently incorporated modifications and initiatives. Included are greater emphasis on imports; increased and more specific targeting of pesticide/commodity combinations by geographic area or country; development of individual district sampling plans for domestic and imported foods; expanded use of single residue methods; linkage of information on foreign pesticide usage with food import volumes; development of an analytical methods research plan; and increased cooperative sampling and data exchange with the states. Initiatives to acquire and utilize private sector and other monitoring data are being explored, and aggressive steps are being taken to inform the public of FDA monitoring results in a timely and understandable manner.     

Expanding and tracking the capabilities of pesticide multiresidue methodology used in the Food and Drug Administration's pesticide monitoring programs

Foods analyzed for pesticide residues in the monitoring programs of the U.S. Food and Drug Administration (FDA) are most often examined by using one or more of the multiresidue methods developed for this purpose over the years. Because no single method can be used for all potential residues, each commodity is examined by a method or methods which will identify and/or determine the chemicals most likely to have been used. FDA conducts research to develop new multiresidue methods, which are included in monitoring programs as needed to cover additional chemicals. FDA's multiresidue methods have undergone continuous study over a 20 year period to ascertain which compounds can and cannot be recovered by them. FDA continues to perform tests to discover a compound's analytical characteristics. Protocols have been published to direct the testing of additional compounds so that new information can be added to the existing compilations. Methods capable of determining residues of single pesticides are used to analyze selected commodities for residues of high priority that cannot be determined by existing multiresidue methods. Pestrak, a computerized listing of pesticide analytical information, has been developed by FDA to keep track of the capabilities of multiresidue methods and the coverage of residues by the single residue methods used in FDA monitoring.     

State findings on pesticide residues in food--1988 and 1989

Findings of pesticide and related chemical residues are presented for 27,065 samples of foods collected and analyzed in 10 state food laboratories over 1988 and 1989 (fiscal years (FY) 88 and 89). These laboratories conduct food regulatory programs compatible with national programs of the U.S. Food and Drug Administration. Of the findings, 6325 samples contained detectable levels of 1 or more pesticide analytes and 418 (or 1.5%) of the total number of samples were deemed to be of regulatory significance.     

宁波市鄞州区农作物农药残留现状与控制对策

对鄞州区种植的稻谷、叶菜类、水果类、豆类、茄果类和块茎类农产品按月进行了411个批次抽样,按照国家相关规定对22个农药项目进行了检测。检测结果发现样本农药项目检出率为0.3%,农产品农药残留合格率97.82%,农药残留检出项目中88.89%是杀虫剂。超出农药残留标准的样本主要是5—10月的青菜,叶菜类超标样本率达到3.72%。农药残留超标样本在平原、滨海地区种植散户中有发现,而在山区各规模农户中均有发现。小学文化程度农户样本农药残留超标率高达4.50%,是大学文化程度农户样本农药残留超标率的6.16倍。为了降低鄞州区农作物农药残留率,提出5方面的控制对策。     

The FDA pesticides monitoring program

The U.S. Food and Drug Administration (FDA) carries out an extensive program to monitor foods for pesticide residues. The 2 main objectives of the program are to enforce tolerances established by the Environmental Protection Agency for pesticide residues on foods and feeds and to determine the incidence and level of pesticide residues in the food supply. Because of the wide diversity of pesticide/commodity combinations encountered, FDA uses a number of different approaches to achieve effective consumer protection. The components of the FDA Pesticides Monitoring Program and the strategy used in its development are described.     

叶类蔬菜低农药残留基因型筛选研究

采用气相色谱法（GC-NPD,ECD）测定毒死蜱和氰戊菊酯残留量,研究了菠菜（Spinacia oleracea L.）和不结球白菜（Brassica campestris L. ssp. Chinensis Makino var. communis Tsen et Lee）中毒死蜱、氰戊菊酯的残留动态。结果表明,菠菜中毒死蜱残留量、不结球白菜中毒死蜱和氰戊菊酯残留量存在着明显的基因型差异。同一不结球白菜基因型,毒死蜱和氰戊菊酯的残留量达到《GB 2763—2005食品中农药最大残留限量》中规定的叶类蔬菜农药最大残留限量所需要的时间存在明显差异,且毒死蜱达到最大残留限量所需要的时间比氰戊菊酯长,因此在选择低农药残留基因型时,应首先考虑农药残留时间长、最大农药残留限量低的农药品种。菠菜品种sp0723、卡尔以及不结球白菜品种矮抗青、无锡605和青选3号属于低农药残留的基因型,在生产上推广应用有利于提高叶类蔬菜的食用安全水平。     

Overweight in urban, low-income, African American and Hispanic children attending Los Angeles elementary schools: research stimulating action

OBJECTIVE: This study was undertaken to establish the prevalence and severity of nutritional problems among low-income children of elementary school age in the Los Angeles Unified School District (LAUSD) in order to collect baseline data to inform policy-makers. DESIGN AND METHODS: A cross-sectional survey of children in 14 elementary schools was conducted from January to June, 1998. Nine hundred and nineteen children were measured and interviewed. The planning, design and data analysis were carried out in collaboration with key LAUSD policy-makers. RESULTS: More than 35% of the sample was classified as being at risk for overweight or overweight according to body mass index. CONCLUSION: There is a high prevalence of children who are at risk for overweight or who are overweight in Los Angeles. This finding has triggered the development of multiple school-based intervention programmes.     

表面增强拉曼光谱检测脐橙果皮混合农药残留

为了研究果皮农药残留快速检测方法。该文以脐橙为例,混合农药(亚胺硫磷和乐果)为研究对象,选用银纳米线作为增强基底,利用共焦显微拉曼光谱仪对农药残留进行检测。通过表面增强拉曼光谱(surface enhanced Raman scattering,SERS)技术,采集脐橙表皮混合农药残留的SERS光谱。对混合农药定性分析,银纳米线对2种农药都有较好的增强效果。对采集的光谱进行预处理后,建立模型,进行定量分析,研究结果表明,经过二阶微分预处理后光谱数据结合偏最小二乘法(partial least squares,PLS)得到的模型预测效果最好,预测相关系数(R_p)为0.954,其预测均方根误差(root-mean-square prediction error,RMSEP)为4.822 mg/L。挑选两种农药特征峰的特征波段,混合农药中亚胺硫磷的特征波段经多元散射校正(multiplicative scatter correction,MSC)处理后,建模效果较好,其中R_p为0.898,RMSEP为6.621 mg/L;混合农药中乐果的特征波段经基线校正处理后,建模效果较好,其中R_p为0.911,RMSEP为7.369 mg/L。研究结果表明SERS技术是一种快速、可靠的检测混合农药残留的方法。     

Regulatory perspective of pesticide analytical enforcement methodology in the United States

A critical overview is presented of the current regulatory problems encountered by the U.S. Environmental Protection Agency in evaluating the adequacy of pesticide analytical enforcement methodologies submitted in support of proposed pesticide tolerances. One of these problems is the development and validation of appropriate, adequate enforcement analytical methods which account for all free or bound/conjugated residue components of the "total toxic residue" in the commodities of concern. Also included is a detailed discussion of suggested improvements in the development and validation of these enforcement methods, for example, integrating radiolabeled metabolism studies with the subsequent development and validation of proposed analytical enforcement methodologies. New procedures are proposed to facilitate the availability of analytical methods to enforcement agencies and other organizations during the method validation process. Future initiatives to use the collaborative study process in the development and validation of Pesticide Analytical Manual, Volume 2, enforcement methods for contemporary pesticides are also discussed.     

Immunoassay of pesticides

Determination of the presence and levels of pesticide residues in food is fundamental in monitoring and regulatory programs. Residues are separated from the food matrix by solvent extraction, followed by cleanup steps. The residues are most often identified and quantitated by instrumental analysis, usually liquid or gas chromatography. Extraction and cleanup are often laborious and time-consuming; determination requires expensive, sophisticated instrumentation. There is a need for rapid, easily performed tests, such as immunoassays, that could be used for screening under field conditions or for quantitation of residues in foods in the laboratory. Although a large number of immunoassays have been developed for pesticide chemicals, very few have been specifically applied to foods, and only a very small number are currently available commercially. The agencies charged with monitoring and regulatory responsibilities--Environmental Protection Agency, Food and Drug Administration, and U.S. Department of Agriculture--as well as professional societies such as AOAC and the International Union of Pure and Applied Chemistry, are investigating and developing guidelines for test kit evaluation and standards to be met before a kit can be accepted as a practical and useful method of analysis for use in their programs.     

An LC/MS/MS method for improved quantitation of the bound residues in the tissues of animals orally dosed with [(14)C]Benomyl

Livers of goats orally dosed with [phenyl(U)-(14)C]benomyl contained radioactive residues which were not extractable using conventional, solvent-based extraction methods. We report a new residue method capable of enhanced extraction of benomyl-derived residues with selective and sensitive quantitation capability for methyl 4-hydroxybenzimidazol-2-ylcarbamate (4-HBC), methyl 5-hydroxybenzimidazol-2-ylcarbamate (5-HBC), and methyl benzimidazol-2-ylcarbamate (MBC). This method involves rigorous Raney-nickel reduction of hypothesized thioether bonds between benomyl residues and polar cellular components. Following acidic dehydration (desulfurization), the polar benomyl-derived residues are extracted into ethyl acetate and analyzed by LC/MS/MS. We have shown this method to be superior to alternative extraction approaches. When applied to goat liver tissue containing [phenyl(U)-(14)C]benomyl-bound residues, the extraction efficiency of total radioactive residues was approximately 30%, and the major benomyl-derived residue was 5-HBC (91-95% of extractable residue) with minor levels of carbendazim (MBC) (5-9%). HPLC/LSC data were consistent with the LC/MS/MS data. The overall method satisfies U.S. regulatory requirements in extraction efficiency, selectivity in detection, and limits of quantitation for benomyl-bound residues.     

农药残留的表面增强拉曼光谱快速检测技术研究现状与展望

果蔬农药残留危害人类健康,施药后,农药分布于其表皮和内部组织,果蔬表面农药绝对残留量低、不均匀,直接光谱检测表征难,而表面增强拉曼散射(surface-enhanced Raman scattering,SERS)技术具有分子级检测精度,可以有效扩增信号,在实现微量物质检测方面优势明显。为此,论文综述了国内外表面增强拉曼散射技术的研究现状,特别是详细介绍了通过设计合理的表面增强拉曼基底结构,实现农药残留信号增强的主要技术手段和表面增强拉曼光谱信号分析方法。在此基础上,指出农药残留的表面增强拉曼检测技术研究中的前沿热点问题,探讨并展望了表面增强拉曼技术在农药残留快速检测方面的发展趋势。基于表面增强拉曼的农药高灵敏度、快速检测表征技术,将在农药违禁使用和农药残留超标监管中有广阔应用前景。     

The persistence and degradation of chlorothalonil and chlorpyrifos in a cranberry bog

The effect of a spray-tank adjuvant on the persistence, distribution, and degradation of two pesticides, chlorothalonil and chlorpyrifos, was studied in a commercial cranberry bog. Pesticides were applied according to label instructions to cranberry plants in paired plot studies. Dislodgeable foliar and whole fruit residues of both pesticides and several degradation products were assessed over a growing season. Residues were also assessed in soil samples collected at fruit harvest. Adjuvant increased both fruit and foliar residues but did not significantly alter the dissipation rate or metabolism of either pesticide. The dissipation of dislodgeable foliar chlorothalonil and chlorpyrifos residues followed first-order kinetics, with estimated half-lives of 12.7 and 3.5 d, respectively. All residue levels on harvested fruit were well below the current U.S. EPA tolerances for fresh cranberries. Chlorothalonil (58%) was the major residue in fruit at harvest (76 d post-chlorothalonil application), with 4-hydroxy-2,5,6-trichloroisophthalonitrile and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene accounting for 26% and 6% of the total residues, respectively. Degradation products accounted for 88% of the total chlorothalonil residues in soil at fruit harvest. The products 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene, 1-carbamoyl-3-cyano-4-hydroxy-2,5,6-trichlorobenzene, 2,5,6-trichloro-4-methylthioisophthalonitrile, and 2,4,5-trichloroisophthalonitrile have not been previously identified in cranberry bog environments. Chlorpyrifos was detected in fruit at harvest (62 d post-chlorpyrifos application), but no metabolites were found. Chlorpyrifos-oxon and 3,5,6-trichloro-2-pyridinol, however, were detected in earlier fruit samples and in foliage and soil samples.     

Pesticide residues in milk and fish samples collected from two Egyptian Governorates

Because of the intensive use of pesticides for the control of certain pests in Egypt, country-wide residue monitoring programs must be established that can cover all the Egyptian Governorates exposed to pesticide treatments. To do so, limited programs must be adopted first, so that current situations and future needs for improved programs are identified. The present paper reports results from a limited monitoring program, which started in 1985 in one governorate and then expanded to include another in 1986. Fish and milk samples were the commodities selected for residue analysis. The results showed that milk samples collected from Beni-Suef Governorate in 1986 had lower levels of organochlorine residues compared to those collected in 1985. Residues in boltifish and catfish samples in 1986 were much higher than those detected in 1985. In comparison with Beni-Suef Governorate, and contrary to expectations, milk derived from Fayoum Governorate in 1986 was more contaminated with pesticides. While the amount of residues in boltifish was comparatively higher, catfish samples were less contaminated.     

Codex alimentarius approach to pesticide residue standards

To protect consumers' health, most countries have maximum legal limits for pesticide residues in foods. Trade difficulties can arise when limits differ between countries. The Codex Alimentarius Commission was established in 1962 to implement the Joint FAO/WHO Food Standards Programme, the purpose of which is to protect consumer health and ensure fair practices in international food trade. The Codex Committee on Pesticide Residues (CCPR), an intergovernmental body which advises the Commission on matters related to pesticide residues, is responsible for establishing maximum residue limits (MRLs) for pesticides in foods and feeds that move in international trade. Codex MRLs are based on residue data obtained mainly from supervised trials that reflect approved pesticide use in accordance with "good agricultural practice." MRLs must be toxicologically acceptable in terms of estimated pesticide intake by consumers. CCPR Working Groups examine problems related to establishing and implementing MRLs, including sampling and methods of analysis. Despite time and effort expended, acceptance and application of Codex MRLs face many problems in international trade.