from: http://www.cfsan.fda.gov/~dms/pes99rep.html
U. S. Food and Drug Administration
Center for Food Safety and Applied Nutrition
Pesticide Program: Residue Monitoring 1999
April 2000
Food and Drug Administration Pesticide Program
Residue Monitoring 1999
This is the thirteenth annual report summarizing the results of the Food and Drug Administration's (FDA) pesticide residue monitoring program. Eight of the twelve previous reports were published in theJournal of the Association of Official Analytical Chemists/Journal of AOAC International; these presented results from Fiscal Years (FY) 1987 through 1994. Results from FY 1995 through FY 1998 were published on FDA's World Wide Web site. This current report includes findings obtained during FY 1999 (October 1, 1998 through September 30, 1999) under regulatory and incidence/level monitoring. Selected Total Diet Study findings for 1999 are also presented. Results in this and earlier reports continue to demonstrate that levels of pesticide residues in the U.S. food supply are well below established safety standards.
FDA Monitoring Program
Three federal government agencies share responsibility for the regulation of pesticides. The Environmental Protection Agency (EPA) registers (i.e.,approves) the use of pesticides and sets tolerances (the maximum amounts of residues that are permitted in or on a food) if use of a particular pesticide may result in residues in or on food (1). Except for meat, poultry, and certain egg products, for which the Food Safety and Inspection Service (FSIS) of the U.S. Department of Agriculture (USDA) is responsible, FDA is charged with enforcing tolerances in imported foods and in domestic foods shipped in interstate commerce. FDA also acquires incidence/level data on particular commodity/pesticide combinations and carries out its market basket survey, the Total Diet Study. Since 1991, USDA's Agricultural Marketing Service (AMS), through contracts with participating states, has carried out a residue testing program directed at raw agricultural products and various processed foods. FSIS and AMS report their pesticide residue data independently.
Regulatory Monitoring
Under this approach to pesticide residue monitoring, FDA samples individual lots of domestically produced and imported foods and analyzes them for pesticide residues to enforce the tolerances set by EPA. Domestic samples are collected as close as possible to the point of production in the distribution system; import samples are collected at the point of entry into U.S. commerce. Emphasis is on the raw agricultural product, which is analyzed as the unwashed, whole (unpeeled), raw commodity. Processed foods are also included. If illegal residues (above EPA tolerance or no tolerance for that particular food/pesticide combination) are found in domestic samples, FDA can invoke various sanctions, such as a seizure or injunction. For imports, shipments may be stopped at the port of entry when illegal residues are found. "Detention without physical examination" (previously called automatic detention) may be invoked for imports based on the finding of one violative shipment if there is reason to believe that the same situation will exist in future lots during the same shipping season for a specific shipper, grower, geographic area, or country.
Factors considered by FDA in planning the types and numbers of samples to collect include review of recently generated state and FDA residue data, regional intelligence on pesticide use, dietary importance of the food, information on the amount of domestic food that enters interstate commerce and of imported food, chemical characteristics and toxicity of the pesticide, and production volume/pesticide usage patterns.
Analytical Methods
To analyze the large numbers of samples whose pesticide treatment history is usually unknown, FDA uses analytical methods capable of simultaneously determining a number of pesticide residues. These multiresidue methods (MRMs) can determine about half of the approximately 400 pesticides with EPA tolerances, and many others that have no tolerances. The most commonly used MRMs can also detect many metabolites, impurities, and alteration products of pesticides (2).
Single residue methods (SRMs) or selective MRMs are used to determine some pesticide residues in foods (2). An SRM usually determines one pesticide; a selective MRM measures a relatively small number of chemically related pesticides. This type of methods is usually more resource-intensive per residue. Therefore, SRMs are much less cost effective than MRMs.
The lower limit of residue measurement in FDA's determination of a specific pesticide is usually well below tolerance levels, which generally range from 0.1 to 50 parts per million (ppm). Residues present at 0.01 ppm and above are usually measurable; however, for individual pesticides, this limit may range from 0.005 to 1 ppm. In this report, the term "trace" is used to indicate residues detected, but at levels below the limit of quantitation (LOQ).
FDA/State Cooperation
FDA field offices interact with their counterparts in many states to increase FDA's effectiveness in pesticide residue monitoring. Memoranda of Understanding or more formal Partnership Agreements have been established between FDA and various state agencies. These agreements provide for more efficient monitoring by broadening coverage and eliminating duplication of effort, thereby maximizing federal and state resources allocated for pesticide activities. These arrangements vary from data sharing, joint planning, and state collection of samples for FDA examination, to FDA/State division of collection, analytical, and enforcement follow-up responsibilities for individual commodities or products of particular origin (i.e., imported vs.domestic products).
Animal Feeds
In addition to monitoring foods for human consumption, FDA also samples and analyzes domestic and imported feeds for pesticide residues. FDA's Center for Veterinary Medicine (CVM) directs this portion of the Agency's monitoring via its Feed Contaminants Compliance Program. Although animal feeds containing violative pesticide residues may present a potential hazard to a number of different categories of animals (e.g., laboratory animals, pets, wildlife, etc.), CVM's monitoring focuses on feeds for livestock and poultry, animals that ultimately become, or produce, foods for human consumption.
International Activities
FDA participates in several international agreements in an effort to minimize incidents of violative residues and remove trade barriers. A standing request for information from foreign governments on pesticides used on their food exported to the U.S. exists, a provision of the Pesticide Monitoring Improvements Act.
Under the auspices of the North American Free Trade Agreement (NAFTA), the U.S., Mexico, and Canada have established a NAFTA Technical Working Group on Pesticides (TWG). The NAFTA Pesticide TWG now serves as the focal point for all pesticide issues that arise among the three NAFTA countries. The TWG reports directly to the NAFTA Sanitary and Phytosanitary Committee.
One of the major goals of the TWG is to ensure that pesticide registrations and tolerances/maximum residue limits in the three countries are harmonized to the extent practical, while strengthening protection of public health and the environment. A number of projects has been undertaken by the TWG to identify differing residue limits in the NAFTA countries and to determine what steps might be taken to harmonize the limits. While this process is difficult, the TWG envisions eventual movement toward a "North America" pesticide registration and tolerance system so that citizens of all three countries can be assured of the safety and legality of foods produced in any one of the NAFTA countries. FDA's activities on the TWG complement its ongoing trilateral cooperation with its counterparts in Mexico and Canada.
Beyond the North American agreements, FDA continues to collaborate with New Zealand to implement a "residue compliance assurance program." New Zealand, historically having excellent compliance with U.S. pesticide tolerances, is implementing a plan whereby their government would provide assurances that selected commodities exported to the U.S. would be in full compliance with U.S. tolerances.
Incidence/Level Monitoring
FDA's pesticide program includes incidence/level monitoring to complement regulatory monitoring. This approach increases FDA's knowledge about particular pesticide/commodity combinations. This information is acquired by analyses of randomly selected samples to determine the presence and levels of selected pesticides. In 1999, FDA issued two special assignments, to determine incidences and levels of certain pesticides in wheat entering the U.S. from Canada, and to determine incidences and levels of forchlorfenuron, a growth regulator, on grapes entering the U.S. from Mexico.
Total Diet Study
The Total Diet Study is the other major element of FDA's pesticide residue monitoring program (3). In its previous annual pesticide reports, FDA provided Total Diet Study findings for 1987-1998 (4a, 4b). More detailed information, including estimated dietary intakes of pesticide residues covering June 1984-April 1986 (5) and July 1986-April 1991 (6), has been published. In September 1991, FDA implemented revisions to the Total Diet Study that were formulated in 1990 (7). These revisions primarily consisted of collection and analysis of an updated and expanded number of food items, addition of six age/sex groups (for a total of 14), and revised analytical coverage. Details of that revision are published (8, 9).
In conducting the Total Diet Study, FDA personnel purchase foods from supermarkets or grocery stores four times per year, once from each of four geographic regions of the country. The 261 foods that comprise each of the 4 market baskets represent over 3,500 different foods reported in USDA food consumption surveys; for example, apple pie represents all fruit pies and fruit pastries. Each market basket is a composite of like foods purchased in three cities in a given region. The foods are prepared table-ready and then analyzed for pesticide residues (as well as radionuclides, industrial chemicals, toxic elements, trace and macro elements, and folic acid). The levels of pesticides found are used in conjunction with USDA food consumption data to estimate the dietary intakes of the pesticide residues.
Results and Discussion
Regulatory Monitoring
Under regulatory monitoring, 9,438 samples were analyzed. Of these 3,426 were domestic and 6,012 were imports.
Figure 1 shows the percentage of the 3,426 domestic samples by commodity group with no residues found, nonviolative residues found, and violative residues found. (A violative residue is defined in this report as a residue which exceeds a tolerance or a residue at a level of regulatory significance for which no tolerance has been established in the sampled food.)
As in earlier years, fruits and vegetables accounted for the largest proportion of the commodities analyzed in 1999; those two commodity groups comprised 72.3% of the total number of domestic samples. In 1999, no violative residues were found in 99.2% of all domestic samples (99.1% in 1996, 98.8% in 1997, 99.2 % in 1998.).
Appendix A contains more detailed data on domestic monitoring findings by commodity, including the total number of samples analyzed, the percent samples with no residues found, and the percent violative samples. Of the 3,426 domestic samples, 60.2% had no detectable residues and 0.8% had violative residues. In the largest commodity groups, fruits and vegetables, 38.8% and 69.7% of the samples, respectively, had no residues detected. 0.6% of the fruit samples and 1.2% of the vegetable samples contained violative residues (Figure 1). In the grains and grain products group, 61.3% of the samples had no residues detected, and 0.2% had violative residues. In the fish/shellfish/other aquatic products group, 71.1% had no detectable residues, and no violative residues were found. In the milk/dairy products/eggs group, 97.4% of the samples had no residues detected, and no violative residues were found. 38 samples of baby foods or formula were analyzed (see category Other). This total included 20 vegetable, 4 cereal, and 14 fruit juice samples. None of the samples had violative residues.
Findings by commodity group for the 6,012 import samples are shown in Figure 2. Fruits and vegetables accounted for 84.1% of these samples. Overall, no violative residues were found in 96.9% of the import samples (97.4% in 1996, 98.4% in 1997, 97.0% in 1998).
Appendix B contains detailed data on the import samples. Of the 6,012 samples analyzed, 65.0% had no residues detected, and 3.1% had violative residues. Fruits and vegetables had 57.5% and 64.8%, respectively, with no residues detected. The fruit group and the vegetable group had 1.8% and 3.9%, respectively, with violative residues. No residues were found in 95.5% of the milk/dairy products/eggs group and in 95.0% of the fish/shellfish group, and no violative residues were found in either of those groups. In the grains and grain products group, 75.4% had no detectable residues, and 0.7% had violative residues.
Pesticide monitoring data collected under FDA's regulatory monitoring approach in 1999 are available to the public as a computer database. This database summarizes FDA 1999 regulatory monitoring coverage and findings by country/commodity/pesticide combination. The database also includes the monitoring data by individual sample from which the summary information was compiled. Information on how to obtain this database as well as those for 1992-1998 is provided at the end of this report.
Geographic Coverage
Domestic. 3,426 domestic samples were collected in 1999 from 47 states (no samples were collected from Rhode Island, New Hampshire, or Oklahoma) and from Puerto Rico. The largest numbers of samples were collected from those states that are the largest producers of fruits and vegetables. Table 1 lists numbers of domestic samples from each location, in order of descending numbers of samples.
Import. 6,012 samples representing food shipments from 92 countries were collected. (The origin of some additional samples was unspecified.) Table 2 lists numbers of samples collected from each country. Mexico, as usual, was the source of the largest number of samples, reflecting the volume and diversity of commodities imported from that country, especially during the winter months.
Domestic/Import Violation Rate Comparison
In 1999, 3,426 domestic and 6,012 import samples were collected and analyzed. Pesticide residues were detected in 39.8% of the domestic samples and in 35.0% of the import samples. Only 0.8% of the domestic samples and only 3.1% of the import samples were violative. Among grains and grain products, the violation rate was 0.2% domestic vs. 0.7% import. No violations were found in the milk/dairy products/eggs group or the fish/shellfish/other aquatic products group among either domestic or import samples. Of domestic fruits, 0.6% were violative; of import fruits, the violation rate was 1.8%. Of vegetables, 1.2% of domestic samples and 3.9% of import samples were violative. In the category "Other" the rates for domestic and import samples were, respectively, 1.4% and 10.6%. Except for this last category, the overall rate of violations is approximately one domestic violation for three import violations. Of the violative samples, eight of the domestic ones and 19 of the import ones contained pesticide residues at levels which exceeded the tolerance for the given chemical in the given commodity. The remainder of the violative samples contained pesticide residues which were not registered in the U.S. for use in the commodities in which they were found; 18 domestic samples and 169 import samples fell in this category.
Pesticide Coverage
Table 3 lists the 366 pesticides that were detectable by the methods used; each of the 90 pesticides that were actually found is indicated by an asterisk.
FDA conducts ongoing research to expand the pesticide coverage of its monitoring program. This research includes testing the behavior of new or previously untested pesticides through existing analytical methods, and development of new methods to cover pesticides that cannot be determined by methods currently used by FDA. The research encompasses both U.S.-registered pesticides and foreign-use pesticides that are not registered in the U.S. The list of pesticides detectable for 1999 (Table 3) reflects the addition of a number of pesticides whose recovery through the analytical methods used was demonstrated as a result of ongoing research.
Animal Feeds
In 1999, 463 domestic and 61 import feed samples were collected and analyzed for residues. Of the 463 domestic samples, 274 (59.2%) contained no detectable pesticide residues, and 7 (1.5%) contained residues which exceeded regulatory guidance (Table 4). Of the 61 import samples, 33 (54.1%) contained no detectable pesticide residues, and 10 (16.4%) contained residues which exceeded regulatory guidance.
The following 5 residues in domestic samples were considered to have exceeded regulatory guidance because there is no tolerance or action level established for the pesticide-commodity combination: 0.028 ppm of chlorpyrifos-methyl on a sample of hominy (feed) from Texas (collected by the Dallas district); 0.047 ppm of chlorpyrifos-methyl on a soybean meal sample from Iowa (collected by the Kansas City district); 0.422 ppm of chlorpyrifos-methyl on a chopped corn sample from Colorado (collected by the Denver district); 0.036 ppm of captafol on a barley sample from Maryland (collected by the Philadelphia district); 0.039 ppm vinclozolin on a canola meal sample from South Dakota (collected by the Minneapolis district).
Two domestic samples had residues that exceeded an EPA tolerance or a FDA requested maximum level. A sample of soybean meal from Kansas and collected by the Kansas City district contained 0.254 ppm of diazinon. This residue exceeded the 0.1 ppm tolerance for diazinon on soybeans in 40 CFR 180.153. The Dallas district collected a sample of bite size dry dog food that contained 125 ppm of ethoxyquin. In 1997, the FDA requested that the maximum level of ethoxyquin in complete dog foods be voluntarily lowered from 150 ppm to 75 ppm.
Ten import samples from Canada (9 canola fines, 1 canola meal) contained 18 pesticide residues that exceeded regulatory guidance. These 10 samples were collected by the Seattle district and contained residues of chlorpyrifos (n=10; range of 0.020-0.090 ppm), malathion (n=7; range of 0.016-1.45 ppm), and vinclozolin (n=1; 0.024 ppm). No tolerance has been established for chlorpyrifos, malathion, or vinclozolin on canola by the EPA.
In the 189 domestic samples of feed in which one or more pesticides were detected, there were 307 residues (233 quantifiable and 74 trace). Malathion, chlorpyrifos-methyl, chlorpyrifos, and diazinon were the most frequently found and accounted for 76.5% of all residues detected (Table 5).
Summary: Regulatory Monitoring
No residues were found in 60.2% of domestic and in 65.0% of import samples (Figure 3) analyzed under FDA's regulatory monitoring approach in 1999. Only 0.8% of domestic and 3.1% of import samples had residue levels that were violative. The findings for 1999 demonstrate that pesticide residue levels in foods are generally well below EPA tolerances, corroborating results presented in earlier reports (4a, 4b). Animal feed samples (463 domestic, 61 import) were analyzed. 59.2% of the domestic samples and 54.1% of the import samples contained no residues.
Incidence/Level Monitoring
Special Surveys
Wheat. In 1999, FDA issued a special assignment to determine incidences and levels of certain pesticides in wheat entering the U.S. from Canada. Specifically, a total of 30 samples of whole grain wheat entering the U.S. from Canada was analyzed for 17 pesticide chemicals, including seven chlorophenoxy acids, which are registered for use on wheat in the U.S. and/or in Canada.
Samples of whole grain wheat were collected by the Minneapolis and Detroit Districts, since they were responsible for the ports where most of wheat from Canada enters the U. S. All 30 samples were sent to the Pacific Regional Laboratory Northwest for the determination of ten pesticides (10). Each sample composite was sent to the Kansas City District laboratory to determine the presence of the chlorophenoxy acids (11). Residues were found in only one wheat sample, 0.002 ppm of dicamba and 0.012 ppm of 2,4-D. These residue levels are well below the U.S. tolerances, which are 2.0 ppm and 0.5 ppm respectively.
Grapes. In 1999, FDA issued a special assignment to determine incidences and levels of forchlorfenuron, a growth regulator, on grapes entering the U.S. from Mexico. FDA had received information that grapes from Mexico might have been treated with forchlorfenuron to improve the growth of berries. Forchlorfenuron is not registered for use in the U.S. Specifically, a total of 52 samples of grapes entering the U.S. from Mexico was analyzed for forchlorfenuron (12)
Samples of fresh table grapes (29 Superior, 18 Flame, 1 Ruby, 1 Red Globe, 3 Thompson) were collected and analyzed for forchlorfenuron by the Los Angeles District, since it was responsible for the ports where nearly all grapes from Mexico enter the U.S. No forchlorfenuron was detected in these samples. The limit of quantitation is 0.003 ppm.
Summary: Incidence/Level Monitoring
Results of the survey of wheat and grapes show that, as in FDA's regulatory monitoring, the levels of most pesticide residues found in these two commodities are generally well below U.S. tolerances, and no violative residues were found.
Total Diet Study
The Total Diet Study (TDS) is distinct from regulatory monitoring in that it determines pesticide residues in foods prepared for consumption (3). To measure the low levels of residues found in the TDS foods, the analytical methods used are modified to permit measurement at levels 5-10 times lower than those normally used in regulatory monitoring. In general, residues present at or above 1 part per billion can be measured. Of the nearly 200 chemicals that can be determined for the analytical methods used, 104 individual residues were found in the foods analyzed in the four market baskets reported here (Market Baskets 98-3, 98-4, 99-1, and 99-2). Among these were 55 pesticides, including 11 which represent more than one related compound counted as a "total", 18 volatile organic compounds for which 70 TDS foods per basket are now being examined, and 10 other organic compounds.
Table 6 lists the 20 most frequently found residues (those found in >2% of the samples), the total number of findings, and the percent occurrence in the four market baskets analyzed in 1999 (1040 food items). The five most frequently observed chemicals, DDT, chlorpyrifos-methyl, malathion, endosulfan, and dieldrin, are the same as those observed for the past several years. The levels of these residues, as well as the others listed in Table 6, are well below regulatory limits.
Information obtained through the TDS is used to estimate dietary intakes of pesticides; these intakes are then compared with established standards. Dietary intakes based on TDS samples collected through mid-1991 have been published previously. (5, 6) Dietary intake estimates based on samples collected since mid-1991 are expected to be published separately in the coming year; a notice will be posted on the TDS website when the paper is scheduled for publication.
For several years, FDA has collected and analyzed a number of baby foods in addition to those covered under TDS. This adjunct to the TDS included 20 different food items in the four baskets represented here (7 fruit juices, 5 fruits, 4 fruit desserts, and 4 grain products). Table 7 lists the15 pesticide residues found in four collections of these foods (78 samples total) in 1999, the percentage occurrence, and ranges of levels found.
Summary: Total Diet Study
In 1999, the types of pesticide residues found and their frequency of occurrence in TDS were generally consistent with those given in previous FDA reports (4a, 4b). The pesticide residue levels found were well below regulatory standards. An adjunct survey of baby foods in 1991-1999 also provided evidence of only small amounts of pesticide residues in those foods.
Summary
A total of 9,438 samples of domestically produced food and imported food from 92 countries was analyzed for pesticide residues in 1999. FDA collected and analyzed animal feed samples (463 domestic, 61 import) for pesticides. 59.2% of the domestic samples and 54.1% of the import samples contained no residues. Total Diet Study findings for 1999 were generally similar to those found in earlier periods; details of findings will be published separately.
This report was compiled through the efforts of the following FDA personnel: Center for Food Safety and Applied Nutrition, Washington, DC: Office of Plant and Dairy Foods and Beverages: Bernadette M. McMahon (retired), Mark S. Wirtz, Carolyn M. Makovi, and Marion Clower, Jr., Division of Pesticides and Industrial Chemicals; Young H. Lee, Division of Programs and Enforcement Policy; S. Kathleen Egan, Division of Risk Assessment; Office of Management Systems: Sharon A. Macuci, Division of Information Resources Management; Center for Veterinary Medicine, Rockville, MD: Randall Lovell; Kansas City District, Lenexa, KS: Sheila K. Egan, David F. Graham, and Mark E. Parmon.
The database containing the data from which this report was derived is also available from FDA's World Wide Web site, at http://www.cfsan.fda.gov. The 1996 through 1998 reports and databases are available at the same site. FDA pesticide monitoring data collected under the regulatory monitoring approach in 1992, 1993, 1994, and 1995 are available for purchase on personal computer diskettes from the National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161 (telephone 1-800-553-6847); or from NTIS's website at http://www.ntis.gov. Order numbers are: 1992, PB94-500899; 1993, PB94-501681; 1994, PB95-503132; and 1995, PB96-503156.
References
(1) Code of Federal Regulations (1999) Title 40, U.S. Government Printing Office, Washington, DC, Parts 180, 185, and 186.
(2) Pesticide Analytical Manual Volume I (3rd Ed., 1994 and subsequent revisions), available from FDA's World Wide Web site at http://www.cfsan.fda.gov, and Volume II (1971 and subsequent revisions), available from National Technical Information Service, Springfield, VA 22161. Food and Drug Administration, Washington, DC.
(3) Pennington, J.A.T., Capar, S.G., Parfitt, C.H., & Edwards, C.W. (1996) History of the Food and Drug Administration's Total Diet Study (Part II), 1987-1993. J. AOAC Int. 79, 163-170.
(4a) Food and Drug Administration (1995) Food and Drug Administration pesticide program - residue monitoring - 1994. J. AOAC Int. 78, 117A-143A (and earlier reports in the series).
(4b) Food and Drug Administration (1996) Food and Drug Administration pesticide program - residue monitoring - 1995, 1998 (and earlier reports in the series). Available from FDA's World Wide Web site at http://www.cfsan.fda.gov.
(5) Gunderson, E.L. (1995) Dietary intakes of pesticides, selected elements, and other chemicals: FDA Total Diet Study, June 1984-April 1986. J. AOAC Int. 78, 910-921.
(6) Gunderson, E.L. (1995) FDA Total Diet Study, July 1986-April 1991, dietary intakes of pesticides, selected elements, and other chemicals. J. AOAC Int. 78, 1353- 1363.
(7) Pennington, J.A.T. (1992) Total Diet Studies: the identification of core foods in the United States food supply. Food Addit. Contam. 9, 253-264.
(8) Pennington, J.A.T. (1992) The 1990 revision of the FDA Total Diet Study. J. Nutr. Educ. 24, 173-178.
(9) Pennington, J.A.T. (1992) Appendices for the 1990 revision of the Food and Drug Administration's Total Diet Study. PB92-176239/AS, National Technical Information Service, Springfield, VA 22161.
(10) Mercer, G.E., and Cummings, L.A. (1999) "Determination of 17 Pesticides of Interest in Wheat Using Mass Spectrometry Selected Ion Monitoring," Laboratory Information Bulletin 4168, FDA, Rockville, MD.
(11) U.S. Food and Drug Administration (1993) Standard Operating Procedure KCP5 for the Total Diet Study: Determination of Chlorophenoxy Acids and Pentachlorophenol Residues. Revised March 24, 1995. FDA/Center For Food Safety and Applied Nutrition, Washington, DC.
(12) Chiu, K.S., Langham, W.S., Lee, W.H., and Luke, M.A., (1999) "Extraction of Forchlorfenuron (CPPU) from Grapes with LC-UV and LC/ESI/MS Determination," Laboratory Information Bulletin 4169, FDA, Rockville, MD.
Figure
1. Summary of Results of Domestic Samples by Commodity
Figure
2. Summary of Results of Import Samples by Commodity
Figure
3. Summary of Results of Domestic vs. Import Samples