Bri
s
Dieldrin in Milk: The Experience of Suffolk County, New York MAHFOUZ H. ZAKI, MD, DRPH, GEORGE S. MILLER, BS, DANIEL W. LANI, BA, LEO A. DAL CORTIVO, PHD, AND MARY C. MCLAUGHLIN, MD, MPH
Introduction Chlorinated hydrocarbons as one group of synthetic pesticides have been in common use since 1945. They are characterized by their stability, residual effect, insolubility in water, and relative specific action. Dieldrin is a widely used pesticide which has been employed for the control of termites and agricultural insects in corn, alfalfa, lawns, turfs, and flowers, and also in household sprays.' Although the use of dieldrin has been restricted in New York State to the control of termites, lumber insects, sod and soil, potential contamination of food items still exists. Chlorinated hydrocarbons are known to last for long periods in the environment, not necessarily at the site of application. Food represents the most important carrier of chemical contamination, including pesticides, being an end product of the three components of the environment-air, water and soil. Unavoidable bactericidal operations, environmental pollution, natural sources, and human error often result in such contamination. The major sources of chlorinated hydrocarbons in food are those of animal origin, namely, milk and dairy products, meat, fish and poultry. Studies conducted by the Food and Drug Administration and other agencies during the 1960s have indicated that these foods are the source of approximately one-half of the total intake of chlorinated hydrocarbon residues.2 Pesticide residues in milk and dairy prodFrom the Suffolk County Department of Health Services, Hauppauge, NY. The authors are, in the order listed, Director of Public Health; Supervisor, Food Control Unit; Public Health Sanitarian; Cfiief Toxicologist; and Commissioner of Health Services. Address reprint requests to Dr. M. H. Zaki, Director of Public Health, Suffolk County Department of Health Services, Veterans Memorial Highway, Hauppauge, NY 11787. This paper, submitted to the Journal April 8, 1977, was revised and accepted for publication August 22, 1977.
260
ucts have been a problem for the dairy industry. On a few occasions, dieldrin was detected in cottage cheese, milk and meat.1 Several governmental agencies are responsible for the regulation and use of pesticide chemicals, for the establishment of tolerance levels and guidelines, and for the monitoring of food for pesticide contamination. These agencies include the Food and Drug Administration, the Environmental Protection Agency, the U.S. Department of Agriculture, the Department of Health, Education, and Welfare, and the Department of the Interior. More than 200 pesticide chemicals are used in the production of food crops. Consequently, one would expect an occasional high incidence of pesticide residues in foods. Regulatory agencies have established almost 3,400 tolerance levels for the various pesticides.2 For dieldrin in milk, tolerance has been set at the zero level and the actionable level at 0.3 ppm (fat basis). Restriction of the use of dieldrin during the past few years has been instrumental in lowering the level of dietary intake of the pesticide. Accidental contamination, however, can occur as a result of unique situations as in the following incident.
The Incident On July 8, 1975, the Food and Drug Administration informed the Division of Public Health of the Suffolk County Department of Health Services in Hauppauge, New York, that milk samples collected on May 30, 1975, from a dairy farm in Eastern Suffolk County, contained dieldrin in concentrations of 3.46-4.12 parts per million. This 10 to 13-fold increase beyond the guidelines prompted the immediate exclusion of this milk supply from processing for human consumption and the initiation of an extensive epidemiologic investigation. The owner and herdsmen were questioned regarding the cows' feeding habits, residence on the farm, AJPH March, 1978, Vol. 68, No. 3
PUBLIC HEALTH BRIEFS
exposure to pesticides and other chemicals, water supply, equipment and other pertinent information. Extensive laboratory examinations were performed on samples of milk from individual cows, the original herd, additions to the herd, the farm tank, and the transportation tank. Testing was also extended to cover various types of feed, including: corn silage, sugar beets, green chop, hay and feed pellets; water from the well and from the stable; and soil from the pasture, corn field, and potato field. The milk samples from individual cows during July showed dieldrin concentrations ranging from 0 to 1.19 ppm, which was lower than the May 30th sample, but in some cases still higher than the actionable level. Consequently, a decision was made to continue the ban on use of the milk for human consumption. Laboratory examination of samples of feed, water, soil, chemicals, insecticides, etc., did not reveal
significant contaminants. Studies conducted at the Michigan State University and in Kentucky indicated that phenobarbital and activated charcoal were instrumental in the removal of dieldrin and similar pesticides from dairy animals.3 4 Chlorinated hydrocarbons are absorbed from the stomach into the blood stream and after circulation are excreted not only in the milk but also in the pancreatic juice, saliva, bile, and probably the intestinal juice which ultimately end in the gastrointestinal tract. The administration of phenobarbital, which increases the ability of the liver to break down the fat soluble dieldrin into water soluble forms, allows it to be excreted by the kidneys in urine. Activated carbon is a pesticide absorbent. The owner was informed of this treatment regimen and advised to treat the contaminated herd, which he did in consultation with his veterinarian. The milk supply was reinstated when the dieldrin level dropped below the actionable level and the barbiturate used during the treatment period could no longer be detected.
The Second Episode Surveillance of the milk supply continued (Figure 1). On November 24, 1975, it was revealed that dieldrin in the farm milk had increased sharply to 1.5 ppm. The continuous monitoring of the milk made it possible to determine that the time of exposure occurred somewhere between November 14-24. The milk was again embargoed and a second investigation undertaken. It included a detailed interviewing of the dairy personnel and the sampling of feel pellets from three separate shipments, water directly from the well and from the stable, the pipeline cleaner, and milk from a number of individual animals as well as a composite of the production of the entire herd. The presence of 0.42 ppm dieldrin in a composite sample of milk from four cows purchased the previous month supported the possibility that we were dealing with a new exposure to the pesticide, and the herd was again placed on the carbon-phenobarbital treatment regimen for a twoweek period. During the investigation, a casual statement made by a AJPH March, 1978, Vol. 68, No. 3
I---,
4.0
1.5-
1.0-
0.5-
z
-z W4030 101811228 2 0
29 ~~~~20
-
May July
Aug.
9
231320 29152411
Sept.
Oct
Nov.
9
15291101219 2318
22 Dec.
Jan'76 Feb. Mar.
Dieldrin was extracted from de-proteinized milk with petroleum ether. After clean-up of the extract on a Florisil column, the concentration of the pesticide was determined employing a Perkin-Elmer 3920 gas chromatograph equipped with a 3Ni electron capture detector.
FIGURE 1-Dieldrin Content in Raw Milk, May 1975-March 1976.
herdsman indicated that the leftover alfalfa hay from a shipment received from a Pennsylvania dealer earlier in the year had been fed to the cows for a few days during the week of November 17, 1975. It was of interest to note that feeding of cows with this lot of hay was discontinued when the herd was placed on a summer feeding program sometime between collection of the original contaminated sample of milk on May 30, 1975 and the date of reporting on July 8, 1975. At the time of the original investigation, no mention had been made of the previous use of this shipment of alfalfa. Consequently, only the hay in current use was sampled. Examination of the suspect alfalfa revealed dieldrin concentrations of 1.5 to 1.85 ppm. Since the hay originated from out-of-state, the Food and Drug Administration was notified. Subsequent samples collected by the state and federal agencies from different bales of the suspect hay were found to contain dieldrin in concentrations ranging from 0.4 ppm to 4.33 ppm.
Conclusion This incident illustrates the potential danger of milk contamination with restricted pesticides from remote sources. It stresses the need for continuous monitoring of agricultural products, including animal feed, in order to prevent accidental contamination of feed with pesticides or their metabolites. The incident also emphasizes the importance of the single casual observation, namely, the temporary feeding of cows with a particular batch of hay, in epidemiologic investigations.
PUBLIC HEALTH BRIEFS
ACKNOWLEDGMENTS The authors greatly appreciate the laboratory assistance provided by the New York State Department of Agriculture and Markets and the Food and Drug Administration.
REFERENCES 1. Report of the Secretary's Commission on Pesticides and Their Relationship to Environmental Health, U.S. Department of Health, Education, and Welfare, 1969.
2. Wessel, J.T. Pesticide Residues in Foods, Special Report No. 9, New York State Agricultural Experiment Station, Cornell University, New York, 1972. 3. Cook, R.M. Pesticide Removal from Dairy Cows, Michigan State University Extension Bulletin E-668, 1969. 4. Braund, D.G., Conner and Moore. Feeding Phenobarbital and Activated Carbon to Accelerate Dieldrin Residue Removal in Contaminated Dairy Herd, Journal of Dairy Science, Vol. 54, No. 3, 1970.
Atypical Plague Bacilli Isolated from Rodents, Fleas, and Man JAMES E. WILLIAMS, PHD, DANIEL N. HARRISON, PHD, THOMAS J. QUAN, PHD, JANET L. MULLINS, ALLAN M. BARNES, PHD, AND DAN C. CAVANAUGH, PHD
Introduction Although most strains of the plague bacillus (Yersinia pestis) isolated from man, animals or fleas have been typical in terms of virulence determinants and susceptibility to antibiotic drugs, unusual forms have been encountered on occasion. In Vietnam, a virulent streptomycin-resistant strain of Y. pestis was isolated from a Norway rat (Rattus norvegicus) collected in Saigon in 1965.1 During 1965 and 1966, two streptomycin-resistant and nine tetracycline-resistant strains were isolated from Vietnamese patients.2 Obviously, drug resistant Y. pestis present a potential threat. In addition, plague bacteria lacking virulence determinants have been recovered from patients, including a strain deficient in the fraction 1 capsular antigen from a fatal case in the United States in 1957,3 a nonpesticinogenic strain from a case in Arizona in 1967,4 and nonpigmented Y. pestis from a clinically mild case in South Africa in 1971.5 Such variants have been detected infrequently and fortuitously. The laboratory methods usually employed for the isolation of plague bacilli from clinical specimens favor the recovery of typical Y. pestis, so the natural occurrence of unusual forms might be greater than presAddress reprint requests to Dr. James E. Williams. Drs. Williams, Harrison, and Cavanaugh (Chief) are in the Department of Hazardous Microorganisms, Division of Communicable Disease and Immunology, Walter Reed Army Institute of Research, Washington, DC, 20012; Dr. Barnes is Chief and Dr. Quan is Assistant Chief of the Plague Branch, Vector-borne Diseases Division, Bureau of Laboratories, Center for Disease Control, Fort Collins, Colorado; Ms. Mullins is Chief, General Microbiology Section, Health and Social Services Department, State of New Mexico Scientific Laboratory System, Albuquerque, NM. This paper, submitted to the Journal June 24, 1977, was revised and accepted for publication August 12, 1977. 262
ent data suggest. Results reported herein represent deliberate attempts to assess the problems presented by aberrant Y. pestis.
Methods In an effort to detect variant forms, plague strains isolated during 1975 and 1976 in the United States, 1974 in Vietnam, and from 1972 to 1974 in Central Java were screened for antibiotic susceptibilities and determinants of virulence. Clinical materials examined included bubo aspirates in CaryBlair transport medium6 from Vietnamese patients and tissues from rock squirrels (Spermophilus variegatus) collected in New Mexico. Original clinical specimens were not available for other isolates, therefore cultures established on agar slopes following animal passage were tested. Typical plague bacilli are characterized by fraction I (Fl) capsular antigen, pigmentation on certain culture media, a VW complex of antigens, and a PCF complex (pesticin I, coagulase, and fibrinolytic factor). Plague strains lacking any of these usually exhibit reduced virulence in laboratory animals.7 Tests used to detect Fl antigen included antiserum-agar and Ouchterlony gel diffusion agar-plate techniques.8 Tests for VW antigens, pigmentation and the PCF complex employed magnesium oxalate, congo-red and pesticin I agars, respectively.9 Antibiotic susceptibility tests employed discs (Difco, Detroit, Michigan) with 10 ,ug streptomycin or 30 ,ug tetracycline at 35°C on Mueller-Hinton agar.1I Plates were swabbed with broth cultures photometrically standardized at 610 nm to give half the density of a McFarland no. I standard. Broth cultures of Y. pestis were prepared at 25°C, near optimal growth temperature, while broth cultures of Escherichia coli AJPH March, 1978, Vol. 68, No. 3
s
Dieldrin in Milk: The Experience of Suffolk County, New York MAHFOUZ H. ZAKI, MD, DRPH, GEORGE S. MILLER, BS, DANIEL W. LANI, BA, LEO A. DAL CORTIVO, PHD, AND MARY C. MCLAUGHLIN, MD, MPH
Introduction Chlorinated hydrocarbons as one group of synthetic pesticides have been in common use since 1945. They are characterized by their stability, residual effect, insolubility in water, and relative specific action. Dieldrin is a widely used pesticide which has been employed for the control of termites and agricultural insects in corn, alfalfa, lawns, turfs, and flowers, and also in household sprays.' Although the use of dieldrin has been restricted in New York State to the control of termites, lumber insects, sod and soil, potential contamination of food items still exists. Chlorinated hydrocarbons are known to last for long periods in the environment, not necessarily at the site of application. Food represents the most important carrier of chemical contamination, including pesticides, being an end product of the three components of the environment-air, water and soil. Unavoidable bactericidal operations, environmental pollution, natural sources, and human error often result in such contamination. The major sources of chlorinated hydrocarbons in food are those of animal origin, namely, milk and dairy products, meat, fish and poultry. Studies conducted by the Food and Drug Administration and other agencies during the 1960s have indicated that these foods are the source of approximately one-half of the total intake of chlorinated hydrocarbon residues.2 Pesticide residues in milk and dairy prodFrom the Suffolk County Department of Health Services, Hauppauge, NY. The authors are, in the order listed, Director of Public Health; Supervisor, Food Control Unit; Public Health Sanitarian; Cfiief Toxicologist; and Commissioner of Health Services. Address reprint requests to Dr. M. H. Zaki, Director of Public Health, Suffolk County Department of Health Services, Veterans Memorial Highway, Hauppauge, NY 11787. This paper, submitted to the Journal April 8, 1977, was revised and accepted for publication August 22, 1977.
260
ucts have been a problem for the dairy industry. On a few occasions, dieldrin was detected in cottage cheese, milk and meat.1 Several governmental agencies are responsible for the regulation and use of pesticide chemicals, for the establishment of tolerance levels and guidelines, and for the monitoring of food for pesticide contamination. These agencies include the Food and Drug Administration, the Environmental Protection Agency, the U.S. Department of Agriculture, the Department of Health, Education, and Welfare, and the Department of the Interior. More than 200 pesticide chemicals are used in the production of food crops. Consequently, one would expect an occasional high incidence of pesticide residues in foods. Regulatory agencies have established almost 3,400 tolerance levels for the various pesticides.2 For dieldrin in milk, tolerance has been set at the zero level and the actionable level at 0.3 ppm (fat basis). Restriction of the use of dieldrin during the past few years has been instrumental in lowering the level of dietary intake of the pesticide. Accidental contamination, however, can occur as a result of unique situations as in the following incident.
The Incident On July 8, 1975, the Food and Drug Administration informed the Division of Public Health of the Suffolk County Department of Health Services in Hauppauge, New York, that milk samples collected on May 30, 1975, from a dairy farm in Eastern Suffolk County, contained dieldrin in concentrations of 3.46-4.12 parts per million. This 10 to 13-fold increase beyond the guidelines prompted the immediate exclusion of this milk supply from processing for human consumption and the initiation of an extensive epidemiologic investigation. The owner and herdsmen were questioned regarding the cows' feeding habits, residence on the farm, AJPH March, 1978, Vol. 68, No. 3
PUBLIC HEALTH BRIEFS
exposure to pesticides and other chemicals, water supply, equipment and other pertinent information. Extensive laboratory examinations were performed on samples of milk from individual cows, the original herd, additions to the herd, the farm tank, and the transportation tank. Testing was also extended to cover various types of feed, including: corn silage, sugar beets, green chop, hay and feed pellets; water from the well and from the stable; and soil from the pasture, corn field, and potato field. The milk samples from individual cows during July showed dieldrin concentrations ranging from 0 to 1.19 ppm, which was lower than the May 30th sample, but in some cases still higher than the actionable level. Consequently, a decision was made to continue the ban on use of the milk for human consumption. Laboratory examination of samples of feed, water, soil, chemicals, insecticides, etc., did not reveal
significant contaminants. Studies conducted at the Michigan State University and in Kentucky indicated that phenobarbital and activated charcoal were instrumental in the removal of dieldrin and similar pesticides from dairy animals.3 4 Chlorinated hydrocarbons are absorbed from the stomach into the blood stream and after circulation are excreted not only in the milk but also in the pancreatic juice, saliva, bile, and probably the intestinal juice which ultimately end in the gastrointestinal tract. The administration of phenobarbital, which increases the ability of the liver to break down the fat soluble dieldrin into water soluble forms, allows it to be excreted by the kidneys in urine. Activated carbon is a pesticide absorbent. The owner was informed of this treatment regimen and advised to treat the contaminated herd, which he did in consultation with his veterinarian. The milk supply was reinstated when the dieldrin level dropped below the actionable level and the barbiturate used during the treatment period could no longer be detected.
The Second Episode Surveillance of the milk supply continued (Figure 1). On November 24, 1975, it was revealed that dieldrin in the farm milk had increased sharply to 1.5 ppm. The continuous monitoring of the milk made it possible to determine that the time of exposure occurred somewhere between November 14-24. The milk was again embargoed and a second investigation undertaken. It included a detailed interviewing of the dairy personnel and the sampling of feel pellets from three separate shipments, water directly from the well and from the stable, the pipeline cleaner, and milk from a number of individual animals as well as a composite of the production of the entire herd. The presence of 0.42 ppm dieldrin in a composite sample of milk from four cows purchased the previous month supported the possibility that we were dealing with a new exposure to the pesticide, and the herd was again placed on the carbon-phenobarbital treatment regimen for a twoweek period. During the investigation, a casual statement made by a AJPH March, 1978, Vol. 68, No. 3
I---,
4.0
1.5-
1.0-
0.5-
z
-z W4030 101811228 2 0
29 ~~~~20
-
May July
Aug.
9
231320 29152411
Sept.
Oct
Nov.
9
15291101219 2318
22 Dec.
Jan'76 Feb. Mar.
Dieldrin was extracted from de-proteinized milk with petroleum ether. After clean-up of the extract on a Florisil column, the concentration of the pesticide was determined employing a Perkin-Elmer 3920 gas chromatograph equipped with a 3Ni electron capture detector.
FIGURE 1-Dieldrin Content in Raw Milk, May 1975-March 1976.
herdsman indicated that the leftover alfalfa hay from a shipment received from a Pennsylvania dealer earlier in the year had been fed to the cows for a few days during the week of November 17, 1975. It was of interest to note that feeding of cows with this lot of hay was discontinued when the herd was placed on a summer feeding program sometime between collection of the original contaminated sample of milk on May 30, 1975 and the date of reporting on July 8, 1975. At the time of the original investigation, no mention had been made of the previous use of this shipment of alfalfa. Consequently, only the hay in current use was sampled. Examination of the suspect alfalfa revealed dieldrin concentrations of 1.5 to 1.85 ppm. Since the hay originated from out-of-state, the Food and Drug Administration was notified. Subsequent samples collected by the state and federal agencies from different bales of the suspect hay were found to contain dieldrin in concentrations ranging from 0.4 ppm to 4.33 ppm.
Conclusion This incident illustrates the potential danger of milk contamination with restricted pesticides from remote sources. It stresses the need for continuous monitoring of agricultural products, including animal feed, in order to prevent accidental contamination of feed with pesticides or their metabolites. The incident also emphasizes the importance of the single casual observation, namely, the temporary feeding of cows with a particular batch of hay, in epidemiologic investigations.
PUBLIC HEALTH BRIEFS
ACKNOWLEDGMENTS The authors greatly appreciate the laboratory assistance provided by the New York State Department of Agriculture and Markets and the Food and Drug Administration.
REFERENCES 1. Report of the Secretary's Commission on Pesticides and Their Relationship to Environmental Health, U.S. Department of Health, Education, and Welfare, 1969.
2. Wessel, J.T. Pesticide Residues in Foods, Special Report No. 9, New York State Agricultural Experiment Station, Cornell University, New York, 1972. 3. Cook, R.M. Pesticide Removal from Dairy Cows, Michigan State University Extension Bulletin E-668, 1969. 4. Braund, D.G., Conner and Moore. Feeding Phenobarbital and Activated Carbon to Accelerate Dieldrin Residue Removal in Contaminated Dairy Herd, Journal of Dairy Science, Vol. 54, No. 3, 1970.
Atypical Plague Bacilli Isolated from Rodents, Fleas, and Man JAMES E. WILLIAMS, PHD, DANIEL N. HARRISON, PHD, THOMAS J. QUAN, PHD, JANET L. MULLINS, ALLAN M. BARNES, PHD, AND DAN C. CAVANAUGH, PHD
Introduction Although most strains of the plague bacillus (Yersinia pestis) isolated from man, animals or fleas have been typical in terms of virulence determinants and susceptibility to antibiotic drugs, unusual forms have been encountered on occasion. In Vietnam, a virulent streptomycin-resistant strain of Y. pestis was isolated from a Norway rat (Rattus norvegicus) collected in Saigon in 1965.1 During 1965 and 1966, two streptomycin-resistant and nine tetracycline-resistant strains were isolated from Vietnamese patients.2 Obviously, drug resistant Y. pestis present a potential threat. In addition, plague bacteria lacking virulence determinants have been recovered from patients, including a strain deficient in the fraction 1 capsular antigen from a fatal case in the United States in 1957,3 a nonpesticinogenic strain from a case in Arizona in 1967,4 and nonpigmented Y. pestis from a clinically mild case in South Africa in 1971.5 Such variants have been detected infrequently and fortuitously. The laboratory methods usually employed for the isolation of plague bacilli from clinical specimens favor the recovery of typical Y. pestis, so the natural occurrence of unusual forms might be greater than presAddress reprint requests to Dr. James E. Williams. Drs. Williams, Harrison, and Cavanaugh (Chief) are in the Department of Hazardous Microorganisms, Division of Communicable Disease and Immunology, Walter Reed Army Institute of Research, Washington, DC, 20012; Dr. Barnes is Chief and Dr. Quan is Assistant Chief of the Plague Branch, Vector-borne Diseases Division, Bureau of Laboratories, Center for Disease Control, Fort Collins, Colorado; Ms. Mullins is Chief, General Microbiology Section, Health and Social Services Department, State of New Mexico Scientific Laboratory System, Albuquerque, NM. This paper, submitted to the Journal June 24, 1977, was revised and accepted for publication August 12, 1977. 262
ent data suggest. Results reported herein represent deliberate attempts to assess the problems presented by aberrant Y. pestis.
Methods In an effort to detect variant forms, plague strains isolated during 1975 and 1976 in the United States, 1974 in Vietnam, and from 1972 to 1974 in Central Java were screened for antibiotic susceptibilities and determinants of virulence. Clinical materials examined included bubo aspirates in CaryBlair transport medium6 from Vietnamese patients and tissues from rock squirrels (Spermophilus variegatus) collected in New Mexico. Original clinical specimens were not available for other isolates, therefore cultures established on agar slopes following animal passage were tested. Typical plague bacilli are characterized by fraction I (Fl) capsular antigen, pigmentation on certain culture media, a VW complex of antigens, and a PCF complex (pesticin I, coagulase, and fibrinolytic factor). Plague strains lacking any of these usually exhibit reduced virulence in laboratory animals.7 Tests used to detect Fl antigen included antiserum-agar and Ouchterlony gel diffusion agar-plate techniques.8 Tests for VW antigens, pigmentation and the PCF complex employed magnesium oxalate, congo-red and pesticin I agars, respectively.9 Antibiotic susceptibility tests employed discs (Difco, Detroit, Michigan) with 10 ,ug streptomycin or 30 ,ug tetracycline at 35°C on Mueller-Hinton agar.1I Plates were swabbed with broth cultures photometrically standardized at 610 nm to give half the density of a McFarland no. I standard. Broth cultures of Y. pestis were prepared at 25°C, near optimal growth temperature, while broth cultures of Escherichia coli AJPH March, 1978, Vol. 68, No. 3
