DDT Levels in Milk of Rural Bennie T.
Indigent
Blacks
Woodard, MS; Bruce B. Ferguson, PhD; David J. Wilson, PhD
milk samples from low-inblacks residing in rural Mississippi and Arkansas and middle-class whites residing in metropolitan Nashville, Tenn, were analyzed for concentrations of DDT and its metabolites. The mean total DDT concentration (DDE [derivative of DDT]+DDT) of 38 samples from the blacks was 447 parts per billion (ppb); the range was 59 to 1,900 ppb. The mean of the 14 samples from Nashville residents was 75 ppb (range, 15 to 133 ppb). The difference in the DDT concentrations in the two populations indicates that rural low-income blacks are still highly contaminated with pesticides, even though the general use of DDT has been banned. Due to the limited amount of information from the donors, no correlation could be made between the DDT concentration and diet, age of child, home pesticide use, or distance of residence from farming fields. (Am J Dis Child 130:400-403, 1976) \s=b\ Human
come
concentrations of DDT and its metabolites in human milk have been of interest not only to mothers planning to breast feed their infants, but also to the general public (Satur-
The
Received for publication Dec 13,1974; accepted
April 1, 1975.
From Maternal and Child Health/Family Planning, Training and Research Center, Meharry Medical College, Nashville, Tenn (Mr Woodard), and the Department of Chemistry, Vanderbilt University School of Arts and Science, Nashville (Drs Wilson and Ferguson). Reprint requests to Department of Chemistry, Vanderbilt University, Nashville, TN 37235 (Dr Wilson).
day Review May 2,1970, 80). Table 1
summarizes the DDT concentrations found in human milk by researchers the world over. The results presented in Table 1 indicate that human milk generally contains DDT concentra¬ tions in excess of the maximum set for cow's milk (50 parts per billion [ppb]) by the World Health Organiza¬ tion1; the medical importance of this is unknown. The scientific and medical litera¬ ture contain no confirmed cases of in¬ fants suffering damage from the DDT in milk, but Fahim and co-work¬ ers2 have reported an increase in mor¬ tality in nursing neonatal rats of mothers heavily treated with DDT. On the other hand, Hayes and col¬ leagues3 reported that adults given DDT in oral doses 550 times greater than the average daily intake for 21.5 months showed no definite clinical or laboratory evidence of damage for the five-year period over which they were examined. However, any dam¬ age to the human might well be ex¬ pected to be found in the susceptible infant rather than the adult, as was observed with the rats previously mentioned. Many low-income black families in the rural southern and southeastern United States are exposed to some¬ what different environmental factors than other Americans. On numerous occasions, workers have been seen chopping cotton in fields while the crop was being sprayed or dusted
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Michigan User on 06/14/2015
with pesticides from airplanes. Many of the homes inhabited by these black families are located within the con¬ fines of cotton fields that are sprayed. Windows, doors, and cracks in the walls of these homes presumably al¬ low the spray to spread within the dwelling, where both food and water may be contaminated. In 1970 alone, nearly a billion pounds of some 900 registered pesti¬ cides were applied (more than 50% for farm use) throughout the United States.4 Although regional statistics are unavailable, a 1964 survey by the US Department of Agriculture indi¬ cated that the cotton market ac¬ counted for 70% of the DDT used on farms.5 Even though a ban on the general use of DDT took effect on Jan 1, 1973,6 a pesticide such as DDT would not immediately be removed from the environment. Blacks in rural poverty areas of the South who have been exposed to high pesticide concentrations for years would be expected to store aboveaverage concentrations of DDT and its metabolites in the adipose tissue due to the high solubility of these compounds in fats and their relative insolubility in aqueous solutions. Since DDT and its metabolites are excreted in the milk, infants nursing black mothers who reside in these areas would be logical candidates for pesticide-related damage. Prelimi¬ nary data on the DDT concentration in human milk from women residing
Table No. of
Locale Australia" Australia (urban)12 Australia (rural)'2
Belgium« Canada« East Germany"
Germany" Hungary" Italy'» Netherlands1» New Guinea (remote)20 New Guinea (exposed)20 Poland2' Poland2' Rumania22 Sweden2' United Kingdom M Ukranian SSR25 USSR»
Yugoslavia27 Arizona, USA2« California, USA2» Colorado, USA20
Georgia, USA2' Pennsylvania, USA22 Washington, DC, USA22 Three cities in USA24 Seven cities in USA'
Samples 45 20 20 20 147 96 43 10
1.—Summary
of DDT Concentrations in Human Milk*
Mean Range of DDT.t Total DDT,t ppb PPb*
Total
15-177 63-956
Range DDT^ ppb
64 228 415 119 139 112
Mean
DDT,§ ppb
Range
Mean DDE,
ppb
ppb
DDE.II
47 32 90 31
72 97 210 81
100 16 16 189
150 30
130-260 250 48
50 55 19
0-179 12-627
0-104 5-409
20011 140 100 22 19 366 293
53011 75-170
107 130
253H 40
30-75
0-120 10-110
40 53 32 10 138
40-160 20-260 0-770 20-360 20-830
70 90 130 120 170
Ellipses in table signify that no figures were given for the number t Ortho-isomers (o.p'i and para-isomers ( , ' of DDE. *
66 40-110
90 97 94
207
100-500 0-370
140 101 102
0-250 20-390 20
of
96
30011 22011 27711
70
samples. Blank spaces signify that the data
Year Concentrations Were Determined 1973 1973 1969 1969 1972 1973 1970 1964 1970 1971 1972 1972 1968 1970 1969 1970 1965 1970 1970 1970 1973 1964 1973 1969 1972 1951 1965 1973 were not
reported.
Parts per billion.
§ Primarily , '-DDT, but , '-DDT included if given. |] Primarily , '-DDE, but , '-DDE included if given. II Concentrations were determined chromatometrically.
in these areas are here compared with data of DDT concentrations in milk from women residing in less exposed suburban areas. MATERIALS AND METHODS
Samples of human milk were obtained from black donors from rural poverty areas in Bolivar County, Mississippi, and Lee County, Arkansas. Samples were ob¬ tained during the period from April 1974 through September 1974. Samples were also collected during the same period from white, urban, middle-class donors residing in metropolitan Nashville, Tenn. Donors were asked to complete a brief question¬ naire regarding their exposure to pesti¬ cides, their food habits, and their weight gain or loss. Samples were kept frozen in polyethylene bags or in glass bottles until analysis. (Cow milk samples frozen in these bags for three months showed no lixiviation of plasticizers.)
DDT and its metabolites were extracted from the samples by slightly modifying the method recommended by the Penine Primate and Pesticides Effects Laboratory of the Environmental Protection Agency.7 One milliliter of the milk sample (spiked with 5 ng of aldrin) was extracted three times with 2.5 ml of acetonitrile in a tissue grinder. The acetonitrile was added to 25 ml of 2% aqueous sodium sulfate and ex¬ tracted three times with 3 ml of hexane. The hexane extract was concentrated to 0.3 ml and then fractionated on a Florisil column. The first fraction was eluted by adding 12 ml of hexane followed by 12 ml of 1% methanol in hexane. The second fraction was eluted with another addition of 12 ml of 1% methanol in hexane. Each fraction was concentrated to 500/d for in¬ jection into the gas Chromatograph. The concentrations of DDT and its me¬ tabolites were determined with a gas Chro¬ matograph that was equipped with a nickel-63 high-temperature electron capture
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Michigan User on 06/14/2015
detector. Pesticide separation was accom¬ on a 183 cm x 6.35 mm outside diameter (od) glass column packed with 1.5% OV-17/1.95% QF-1 on acid-washed,
plished
dimethylchlorosilane (DMCS)-treated,
80/ 100 mesh Chromosorb W. Pesticide identi¬ fication was verified on another column packed with 4% SE-30/6% OV-210 on Chro¬ mosorb W. The following conditions were used during pesticide quantitation: volume of injection, 5/d; column temperature, 200 C; column nitrogen flow rate, 60 ml/min; detector purge flow rate, 20 ml/min. Standards were prepared from pesti¬ cides received from the Perrine Primate and Pesticide Effects Laboratory using the method suggested by them.8 Working standards were prepared in hexane and contained a mixture of aldrin and the isomers of DDE (derivative of DDT), DDD and (dichlorodiphenyldichloroethane), DDT. One standard used contained 10 ng/ml aldrin, 20 ng/ml o,p' (ortho-isomer) DDE
Table 2.—Pesticide
Study 1
Study 2
Recovery Rates*
Study 3
Study 4
Amount
Amount
Amount
Amount
Amount
Amount
Amount
SD of
Added,
Added,
Mean Amount
Pesti¬
Received,
Amount
Received,
Added,
Received,
Added,
Received,
Recovered,
Recovery,
cides!
ns
ng 16 32 32 64 64 64 64
86 97 90 66 26 91 95
ng 32 64 64 128 128 128 128
84 94 90 54 26 87 94
80 96 92 61 28 91
t8
Aldrin
, '-DDE p,p'-DDE o,p'-DDD p,p -DDD
o,p'-DDT p,p'-DDT
16 16 16
%
75 104 97 52 14 96 102
%
ng 8
74 90 88 72
16 16 32 32 32 32
48 90 94
%
%
%
%
±7
fc12 t15 ±5 ±6
* One-milliliter cow's milk samples were spiked with the indicated amounts of each pesticide and were analyzed in the same manner as the human milk samples. Each recovery cited in the table is the mean of two samples spiked with each pesticide concentration. f Nomenclature is as follows: aldrin, [1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-endo-exo-1,4:5,8-d¡methanonapthalene]; , '-
, '-DDE, [1,1-dichloro-2,2-bis (p-chlorophenyl)ethylenel; , '-DDD, [2-(ochlorophenyl)-2-(p-chlorophenyl)-1,1-dichloroethane]; , '-DDD, [2,2-bis (p-chlorophenyl)-l, 1-dichloroethane]; , '-DDT, [1,1,1-trichloro2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane]; , '-DDT, [1,1,1-trichloro-2,2-bis (p-chlorophenyl)ethane]. DDE, [1,1-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethylene];
, ' (para-isomer) DDE, and 40 ng/ml , '-DDD, , '- , , '-DDT, and p,p'-
and
DDT. A second standard contained half the concentration of each of these com¬ pounds. Samples with excessively high pes¬ ticide concentrations on the first analysis were diluted quantitatively with hexane so that a 5µ1 injection would deliver a quan¬ tity of each pesticide that would be less than that contained in the more concen¬ trated standard. The samples were ana¬ lyzed by injecting one of the standards and then running four samples; this was fol¬ lowed by injecting the remaining stan¬ dard. Each pesticide concentration was determined by measuring peak heights and then interpolating between the peak heights of the standards run on either side of the sample. The limit of detection of this method was found to be 0.5 ppb aldrin, 1.0 ppb DDE, and 2.0 ppb DDD and DDT in the milk. Analyses of distilled water samples es¬ tablished that reagents were not introduc¬ ing spurious results. Preliminary studies using commercial cow's milk indicated that the pesticide levels present in these speci¬ mens of cow's milk were below the detec¬ tion limit of the method, which was pre¬ sumably due to the stringent exclusion of these pesticides from use in the dairy in¬ dustry in recent years. Eight samples of fresh cow milk were spiked with the pesti¬ cides of interest and analyzed using the same method as for human milk samples to check the recovery and precision of the method. Table 2 summarizes the results. The low recoveries found for DDD were expected, since only the first fraction eluted from the Florisil column was ana¬ lyzed and the DDD is known to be split be¬ tween fraction one and two.' Only fraction one was analyzed when human milk sam¬ ples were run. Since the DDD recovered on
0-5049 99
400" 800*KXX) 200600699 299 499 899 Total DDT Concentration, ppb
Distribution of total DDT concentrations in the milk of black rural women (open bars) and of white urban women (hatched bars). Values expressed in parts per billion (ppb).
preliminary
runs was less than 10 ppb, it decided that the extra time and effort required to collect and analyze the second fraction would not be worthwhile. Multiple runs of three human milk sam¬ ples were made to check the reproducibility of the method. We obtained a reproducibility of about ± 10% for analyses over a four-month period, during which all the analyses of the study were carried out. was
RESULTS
A total of 38 samples from black donors in rural poverty areas and 14 samples from white, urban, middleclass donors in Nashville were ana-
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The mean total DDT concen¬ tration in the samples from blacks was 447 ppb with a standard devia¬ tion of the measurements of 465 ppb. The range of concentrations was from 59 to 1,900 ppb (Figure). The samples from the Nashville residents contained a mean total DDT concen¬ tration of 75 ppb with a standard de¬ viation of the measurements of 40 ppb. The range of concentrations was from 15 to 133 ppb. Approximately 170 ppb with this population was found three years ago.9 The mean of the DDT concentra-
lyzed.
tions found in the poverty
areas was
compared with that of the samples
from the Nashville area; it was found that the probability that the means differ due to chance was 8x 10 \ In all probability, most of this difference can be ascribed to the greater pesti¬ cide exposure of the blacks. However, other factors may be involved as well. Davies et al8 and Hoffman and coworkers10 found substantially higher DDT concentrations in the adipose tissue of blacks than in that of whites. The results were obtained by analyzing specimens of adipose tissue from persons accidentally killed. Al¬ though there were not as many sam¬ ples from blacks analyzed, the sam¬ ples from blacks contained over 50% more DDT than the samples from whites. In our study, all the samples from the rural poverty areas were from black donors, while those sam-
from the Nashville area were from white middle-class donors. A ra¬ cial comparison of DDT concentra¬ tions in human milk could be made if samples were analyzed from middleclass blacks in Nashville and whites of the same socioeconomic group as the blacks from the poverty areas; we did not have access to such samples. There appeared to be no correlation (correlation coefficient, —0.2) between the age of the black donor and the DDT concentration. It was not pos¬ sible to correlate the DDT concentra¬ tions with other variables such as diet, age of child, home pesticide use, or distance of residence from farming fields, because many of the question¬ naires were not filled out completely.
pies
has been
banned,6 this study indicates population that is obviously still highly contaminated with pesticides. a
It is necessary to reiterate here that have found no reported cases of breast-fed infants being harmed by the DDT, but these poor blacks from agricultural areas appear to be the population to study to determine if infants are in fact harmed by the DDT in human milk. We urge other researchers to systematically study this group of women (whose milk contained an average DDT concentra¬ tion of almost a factor of ten greater than the World Health Organization limit for cow's milk) and attempt to determine if infants are affected by DDT concentrations in human milk. we
COMMENT
of DDT
This work was supported by US Environmen¬ tal Protection Agency grant No. R 803564.
carbon pesticide residue in Queensland human milks. Med J Aust 2:261-264, 1973. 13. Heyndrickx, Maes, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 14. Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 15. Knoll W, Jayaraman S: Contamination of human milk with chlorinated hydrocarbons. Nahrung 17:599-615, 1973. 16. Acker, Shulte, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 17. Denes A: 1963 Year Book of the Institute of Nutrition. Budapest, State Publishing House, 1964, p 47. 18. Paccagnella, Prati, Cavazzini, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 19. Tuinstra, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 20. Hornabrook RW, Dyment PG, Gomes ED, et al: DDT residues in human milk from New Guinea natives. Med J Aust 1:1297-1300, 1972. 21. Bronisz H, Ochynski J: DDT and DDE levels in the milk of women residing in Lublin Province. Pediatr Pol 48:445-451, 1973. 22. Uterman, Sirghie, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Pub-
lic Health 63:125-132, 1972. 23. Westoo, Noren, Andersson, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 24. Egan H, Goulding R, Roburn J, et al: Organochlorine pesticide residues in human fat and human milk. Br Med J 2:66-69, 1965. 25. Gracheva GV: DDT excretion with the milk of nursing mothers occupationally unexposed to this insecticide. Vopr Pitan 29:75-78, 1970. 26. Suvak LN: Level of DDT and DDE in the milk of nursing women. Zdravookhr Ross Fed 13:19-21, 1970. 27. Adamovic VM, Hus M, Sindzic M, et al: Accumulation of organochlorine insecticides in some organs and fatty tissues of the Serbian population. Hrana IIshrana 11:12-20, 1970. 28. Hagyard SB, Brown WH, Stull JW, et al: DDT and DDE content of human milk in Arizona. Bull Environ Contam Toxicol 9:169-172, 1973. 29. West I: Pesticides as contaminants. Arch Environ Health 9:626-633, 1964. 30. Savage EP, Tesari JD, Malberg JW, et al: Organochlorine pesticide residues and polychlorinated biphenyls in human milk. Pestic Monit J 7:1-5, 1973. 31. Curley A, Kimbrough R: Chlorinated hydrocarbon insecticides in plasma and milk of pregnant and lactating women. Arch Environ Health 18:156-164, 1969. 32. Kroger M: Insecticide residues in human milk. J Pediatr 80:401-405, 1972. 33. Laug EP, Kunze FM, Prickett CS: Occurrence of DDT in human fat and milk. Arch Industr Hyg Occup Med 3:245-246, 1951. 34. Quinby GE, Armstrong JF, Durham WF: DDT in human milk. Nature 207:726-728, 1965.
Although the general
use
References 1. Pesticide residues in fat: Report of the 1968 Joint Food and Agricultural Organization/World Health Organization meeting. WHO Tech Report, series 417, 1969. 2. Fahim MS, Bennett R, Hall DG: Effect of DDT on the nursing neonate. Nature 228:1222\x=req-\ 1223, 1970. 3. Hayes WJ Jr, Dale WE, Pirkle CI: Evidence of safety of long-term, high, oral doses of DDT for man. Arch Environ Health 22:119-135, 1971. 4. Ecological Effects of Pesticides on Non-target Species. Executive Office of the President, Office of Science and Technology, June, 1971. 5. Report of the Secretary's Commission on Pesticides and Their Relationship to Environmental Health: Part I andII. US Dept of Health, Education, and Welfare, 1969. 6. Ruckelshaus WD: Order Banning General Use of DDT. Environmental Protection Agency, June 14, 1972. 7. Thompson JF: Analysis of Pesticide Residues in Human and Environmental Samples. Perrine Primate and Pesticide Effects Laboratory, Environmental Protection Agency, Research Triangle Park, NC, 1972. 8. Davies JE, Edmundson WF, Schneider NJ, et al: Problems of prevalence of pesticide residues in humans, in Davies JE, Edmundson WF (eds): Epidemiology of DDT. Mount Kisco, NY, Future Publishing Co, 1972. 9. Wilson DJ, Locker DJ, Ritzen CA, et al: DDT concentrations in human milk. Am J Dis Child 125:814-817, 1973. 10. Hoffman WS, Adler H, Fishbein WI, et al: Relation of pesticide concentrations in fat to pathological changes in tissues. Arch Environ Health 15:758-765, 1967. 11. Siyali DS: Polychlorinated biphenyls, hexachlorobenzene, and other organochlorine pesticides in human milk. Med J Aust 2:815-818, 1973. 12. Miller GJ, Fox JA: Chlorinated hydro-
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Indigent
Blacks
Woodard, MS; Bruce B. Ferguson, PhD; David J. Wilson, PhD
milk samples from low-inblacks residing in rural Mississippi and Arkansas and middle-class whites residing in metropolitan Nashville, Tenn, were analyzed for concentrations of DDT and its metabolites. The mean total DDT concentration (DDE [derivative of DDT]+DDT) of 38 samples from the blacks was 447 parts per billion (ppb); the range was 59 to 1,900 ppb. The mean of the 14 samples from Nashville residents was 75 ppb (range, 15 to 133 ppb). The difference in the DDT concentrations in the two populations indicates that rural low-income blacks are still highly contaminated with pesticides, even though the general use of DDT has been banned. Due to the limited amount of information from the donors, no correlation could be made between the DDT concentration and diet, age of child, home pesticide use, or distance of residence from farming fields. (Am J Dis Child 130:400-403, 1976) \s=b\ Human
come
concentrations of DDT and its metabolites in human milk have been of interest not only to mothers planning to breast feed their infants, but also to the general public (Satur-
The
Received for publication Dec 13,1974; accepted
April 1, 1975.
From Maternal and Child Health/Family Planning, Training and Research Center, Meharry Medical College, Nashville, Tenn (Mr Woodard), and the Department of Chemistry, Vanderbilt University School of Arts and Science, Nashville (Drs Wilson and Ferguson). Reprint requests to Department of Chemistry, Vanderbilt University, Nashville, TN 37235 (Dr Wilson).
day Review May 2,1970, 80). Table 1
summarizes the DDT concentrations found in human milk by researchers the world over. The results presented in Table 1 indicate that human milk generally contains DDT concentra¬ tions in excess of the maximum set for cow's milk (50 parts per billion [ppb]) by the World Health Organiza¬ tion1; the medical importance of this is unknown. The scientific and medical litera¬ ture contain no confirmed cases of in¬ fants suffering damage from the DDT in milk, but Fahim and co-work¬ ers2 have reported an increase in mor¬ tality in nursing neonatal rats of mothers heavily treated with DDT. On the other hand, Hayes and col¬ leagues3 reported that adults given DDT in oral doses 550 times greater than the average daily intake for 21.5 months showed no definite clinical or laboratory evidence of damage for the five-year period over which they were examined. However, any dam¬ age to the human might well be ex¬ pected to be found in the susceptible infant rather than the adult, as was observed with the rats previously mentioned. Many low-income black families in the rural southern and southeastern United States are exposed to some¬ what different environmental factors than other Americans. On numerous occasions, workers have been seen chopping cotton in fields while the crop was being sprayed or dusted
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Michigan User on 06/14/2015
with pesticides from airplanes. Many of the homes inhabited by these black families are located within the con¬ fines of cotton fields that are sprayed. Windows, doors, and cracks in the walls of these homes presumably al¬ low the spray to spread within the dwelling, where both food and water may be contaminated. In 1970 alone, nearly a billion pounds of some 900 registered pesti¬ cides were applied (more than 50% for farm use) throughout the United States.4 Although regional statistics are unavailable, a 1964 survey by the US Department of Agriculture indi¬ cated that the cotton market ac¬ counted for 70% of the DDT used on farms.5 Even though a ban on the general use of DDT took effect on Jan 1, 1973,6 a pesticide such as DDT would not immediately be removed from the environment. Blacks in rural poverty areas of the South who have been exposed to high pesticide concentrations for years would be expected to store aboveaverage concentrations of DDT and its metabolites in the adipose tissue due to the high solubility of these compounds in fats and their relative insolubility in aqueous solutions. Since DDT and its metabolites are excreted in the milk, infants nursing black mothers who reside in these areas would be logical candidates for pesticide-related damage. Prelimi¬ nary data on the DDT concentration in human milk from women residing
Table No. of
Locale Australia" Australia (urban)12 Australia (rural)'2
Belgium« Canada« East Germany"
Germany" Hungary" Italy'» Netherlands1» New Guinea (remote)20 New Guinea (exposed)20 Poland2' Poland2' Rumania22 Sweden2' United Kingdom M Ukranian SSR25 USSR»
Yugoslavia27 Arizona, USA2« California, USA2» Colorado, USA20
Georgia, USA2' Pennsylvania, USA22 Washington, DC, USA22 Three cities in USA24 Seven cities in USA'
Samples 45 20 20 20 147 96 43 10
1.—Summary
of DDT Concentrations in Human Milk*
Mean Range of DDT.t Total DDT,t ppb PPb*
Total
15-177 63-956
Range DDT^ ppb
64 228 415 119 139 112
Mean
DDT,§ ppb
Range
Mean DDE,
ppb
ppb
DDE.II
47 32 90 31
72 97 210 81
100 16 16 189
150 30
130-260 250 48
50 55 19
0-179 12-627
0-104 5-409
20011 140 100 22 19 366 293
53011 75-170
107 130
253H 40
30-75
0-120 10-110
40 53 32 10 138
40-160 20-260 0-770 20-360 20-830
70 90 130 120 170
Ellipses in table signify that no figures were given for the number t Ortho-isomers (o.p'i and para-isomers ( , ' of DDE. *
66 40-110
90 97 94
207
100-500 0-370
140 101 102
0-250 20-390 20
of
96
30011 22011 27711
70
samples. Blank spaces signify that the data
Year Concentrations Were Determined 1973 1973 1969 1969 1972 1973 1970 1964 1970 1971 1972 1972 1968 1970 1969 1970 1965 1970 1970 1970 1973 1964 1973 1969 1972 1951 1965 1973 were not
reported.
Parts per billion.
§ Primarily , '-DDT, but , '-DDT included if given. |] Primarily , '-DDE, but , '-DDE included if given. II Concentrations were determined chromatometrically.
in these areas are here compared with data of DDT concentrations in milk from women residing in less exposed suburban areas. MATERIALS AND METHODS
Samples of human milk were obtained from black donors from rural poverty areas in Bolivar County, Mississippi, and Lee County, Arkansas. Samples were ob¬ tained during the period from April 1974 through September 1974. Samples were also collected during the same period from white, urban, middle-class donors residing in metropolitan Nashville, Tenn. Donors were asked to complete a brief question¬ naire regarding their exposure to pesti¬ cides, their food habits, and their weight gain or loss. Samples were kept frozen in polyethylene bags or in glass bottles until analysis. (Cow milk samples frozen in these bags for three months showed no lixiviation of plasticizers.)
DDT and its metabolites were extracted from the samples by slightly modifying the method recommended by the Penine Primate and Pesticides Effects Laboratory of the Environmental Protection Agency.7 One milliliter of the milk sample (spiked with 5 ng of aldrin) was extracted three times with 2.5 ml of acetonitrile in a tissue grinder. The acetonitrile was added to 25 ml of 2% aqueous sodium sulfate and ex¬ tracted three times with 3 ml of hexane. The hexane extract was concentrated to 0.3 ml and then fractionated on a Florisil column. The first fraction was eluted by adding 12 ml of hexane followed by 12 ml of 1% methanol in hexane. The second fraction was eluted with another addition of 12 ml of 1% methanol in hexane. Each fraction was concentrated to 500/d for in¬ jection into the gas Chromatograph. The concentrations of DDT and its me¬ tabolites were determined with a gas Chro¬ matograph that was equipped with a nickel-63 high-temperature electron capture
Downloaded From: http://archpedi.jamanetwork.com/ by a University of Michigan User on 06/14/2015
detector. Pesticide separation was accom¬ on a 183 cm x 6.35 mm outside diameter (od) glass column packed with 1.5% OV-17/1.95% QF-1 on acid-washed,
plished
dimethylchlorosilane (DMCS)-treated,
80/ 100 mesh Chromosorb W. Pesticide identi¬ fication was verified on another column packed with 4% SE-30/6% OV-210 on Chro¬ mosorb W. The following conditions were used during pesticide quantitation: volume of injection, 5/d; column temperature, 200 C; column nitrogen flow rate, 60 ml/min; detector purge flow rate, 20 ml/min. Standards were prepared from pesti¬ cides received from the Perrine Primate and Pesticide Effects Laboratory using the method suggested by them.8 Working standards were prepared in hexane and contained a mixture of aldrin and the isomers of DDE (derivative of DDT), DDD and (dichlorodiphenyldichloroethane), DDT. One standard used contained 10 ng/ml aldrin, 20 ng/ml o,p' (ortho-isomer) DDE
Table 2.—Pesticide
Study 1
Study 2
Recovery Rates*
Study 3
Study 4
Amount
Amount
Amount
Amount
Amount
Amount
Amount
SD of
Added,
Added,
Mean Amount
Pesti¬
Received,
Amount
Received,
Added,
Received,
Added,
Received,
Recovered,
Recovery,
cides!
ns
ng 16 32 32 64 64 64 64
86 97 90 66 26 91 95
ng 32 64 64 128 128 128 128
84 94 90 54 26 87 94
80 96 92 61 28 91
t8
Aldrin
, '-DDE p,p'-DDE o,p'-DDD p,p -DDD
o,p'-DDT p,p'-DDT
16 16 16
%
75 104 97 52 14 96 102
%
ng 8
74 90 88 72
16 16 32 32 32 32
48 90 94
%
%
%
%
±7
fc12 t15 ±5 ±6
* One-milliliter cow's milk samples were spiked with the indicated amounts of each pesticide and were analyzed in the same manner as the human milk samples. Each recovery cited in the table is the mean of two samples spiked with each pesticide concentration. f Nomenclature is as follows: aldrin, [1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-endo-exo-1,4:5,8-d¡methanonapthalene]; , '-
, '-DDE, [1,1-dichloro-2,2-bis (p-chlorophenyl)ethylenel; , '-DDD, [2-(ochlorophenyl)-2-(p-chlorophenyl)-1,1-dichloroethane]; , '-DDD, [2,2-bis (p-chlorophenyl)-l, 1-dichloroethane]; , '-DDT, [1,1,1-trichloro2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane]; , '-DDT, [1,1,1-trichloro-2,2-bis (p-chlorophenyl)ethane]. DDE, [1,1-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethylene];
, ' (para-isomer) DDE, and 40 ng/ml , '-DDD, , '- , , '-DDT, and p,p'-
and
DDT. A second standard contained half the concentration of each of these com¬ pounds. Samples with excessively high pes¬ ticide concentrations on the first analysis were diluted quantitatively with hexane so that a 5µ1 injection would deliver a quan¬ tity of each pesticide that would be less than that contained in the more concen¬ trated standard. The samples were ana¬ lyzed by injecting one of the standards and then running four samples; this was fol¬ lowed by injecting the remaining stan¬ dard. Each pesticide concentration was determined by measuring peak heights and then interpolating between the peak heights of the standards run on either side of the sample. The limit of detection of this method was found to be 0.5 ppb aldrin, 1.0 ppb DDE, and 2.0 ppb DDD and DDT in the milk. Analyses of distilled water samples es¬ tablished that reagents were not introduc¬ ing spurious results. Preliminary studies using commercial cow's milk indicated that the pesticide levels present in these speci¬ mens of cow's milk were below the detec¬ tion limit of the method, which was pre¬ sumably due to the stringent exclusion of these pesticides from use in the dairy in¬ dustry in recent years. Eight samples of fresh cow milk were spiked with the pesti¬ cides of interest and analyzed using the same method as for human milk samples to check the recovery and precision of the method. Table 2 summarizes the results. The low recoveries found for DDD were expected, since only the first fraction eluted from the Florisil column was ana¬ lyzed and the DDD is known to be split be¬ tween fraction one and two.' Only fraction one was analyzed when human milk sam¬ ples were run. Since the DDD recovered on
0-5049 99
400" 800*KXX) 200600699 299 499 899 Total DDT Concentration, ppb
Distribution of total DDT concentrations in the milk of black rural women (open bars) and of white urban women (hatched bars). Values expressed in parts per billion (ppb).
preliminary
runs was less than 10 ppb, it decided that the extra time and effort required to collect and analyze the second fraction would not be worthwhile. Multiple runs of three human milk sam¬ ples were made to check the reproducibility of the method. We obtained a reproducibility of about ± 10% for analyses over a four-month period, during which all the analyses of the study were carried out. was
RESULTS
A total of 38 samples from black donors in rural poverty areas and 14 samples from white, urban, middleclass donors in Nashville were ana-
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The mean total DDT concen¬ tration in the samples from blacks was 447 ppb with a standard devia¬ tion of the measurements of 465 ppb. The range of concentrations was from 59 to 1,900 ppb (Figure). The samples from the Nashville residents contained a mean total DDT concen¬ tration of 75 ppb with a standard de¬ viation of the measurements of 40 ppb. The range of concentrations was from 15 to 133 ppb. Approximately 170 ppb with this population was found three years ago.9 The mean of the DDT concentra-
lyzed.
tions found in the poverty
areas was
compared with that of the samples
from the Nashville area; it was found that the probability that the means differ due to chance was 8x 10 \ In all probability, most of this difference can be ascribed to the greater pesti¬ cide exposure of the blacks. However, other factors may be involved as well. Davies et al8 and Hoffman and coworkers10 found substantially higher DDT concentrations in the adipose tissue of blacks than in that of whites. The results were obtained by analyzing specimens of adipose tissue from persons accidentally killed. Al¬ though there were not as many sam¬ ples from blacks analyzed, the sam¬ ples from blacks contained over 50% more DDT than the samples from whites. In our study, all the samples from the rural poverty areas were from black donors, while those sam-
from the Nashville area were from white middle-class donors. A ra¬ cial comparison of DDT concentra¬ tions in human milk could be made if samples were analyzed from middleclass blacks in Nashville and whites of the same socioeconomic group as the blacks from the poverty areas; we did not have access to such samples. There appeared to be no correlation (correlation coefficient, —0.2) between the age of the black donor and the DDT concentration. It was not pos¬ sible to correlate the DDT concentra¬ tions with other variables such as diet, age of child, home pesticide use, or distance of residence from farming fields, because many of the question¬ naires were not filled out completely.
pies
has been
banned,6 this study indicates population that is obviously still highly contaminated with pesticides. a
It is necessary to reiterate here that have found no reported cases of breast-fed infants being harmed by the DDT, but these poor blacks from agricultural areas appear to be the population to study to determine if infants are in fact harmed by the DDT in human milk. We urge other researchers to systematically study this group of women (whose milk contained an average DDT concentra¬ tion of almost a factor of ten greater than the World Health Organization limit for cow's milk) and attempt to determine if infants are affected by DDT concentrations in human milk. we
COMMENT
of DDT
This work was supported by US Environmen¬ tal Protection Agency grant No. R 803564.
carbon pesticide residue in Queensland human milks. Med J Aust 2:261-264, 1973. 13. Heyndrickx, Maes, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 14. Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 15. Knoll W, Jayaraman S: Contamination of human milk with chlorinated hydrocarbons. Nahrung 17:599-615, 1973. 16. Acker, Shulte, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 17. Denes A: 1963 Year Book of the Institute of Nutrition. Budapest, State Publishing House, 1964, p 47. 18. Paccagnella, Prati, Cavazzini, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 19. Tuinstra, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 20. Hornabrook RW, Dyment PG, Gomes ED, et al: DDT residues in human milk from New Guinea natives. Med J Aust 1:1297-1300, 1972. 21. Bronisz H, Ochynski J: DDT and DDE levels in the milk of women residing in Lublin Province. Pediatr Pol 48:445-451, 1973. 22. Uterman, Sirghie, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Pub-
lic Health 63:125-132, 1972. 23. Westoo, Noren, Andersson, cited by Ritcey WR, Savary G, McCully KA: Organochlorine insecticide residues in human milk, evaporated milk, and some milk substitutes in Canada. Can J Public Health 63:125-132, 1972. 24. Egan H, Goulding R, Roburn J, et al: Organochlorine pesticide residues in human fat and human milk. Br Med J 2:66-69, 1965. 25. Gracheva GV: DDT excretion with the milk of nursing mothers occupationally unexposed to this insecticide. Vopr Pitan 29:75-78, 1970. 26. Suvak LN: Level of DDT and DDE in the milk of nursing women. Zdravookhr Ross Fed 13:19-21, 1970. 27. Adamovic VM, Hus M, Sindzic M, et al: Accumulation of organochlorine insecticides in some organs and fatty tissues of the Serbian population. Hrana IIshrana 11:12-20, 1970. 28. Hagyard SB, Brown WH, Stull JW, et al: DDT and DDE content of human milk in Arizona. Bull Environ Contam Toxicol 9:169-172, 1973. 29. West I: Pesticides as contaminants. Arch Environ Health 9:626-633, 1964. 30. Savage EP, Tesari JD, Malberg JW, et al: Organochlorine pesticide residues and polychlorinated biphenyls in human milk. Pestic Monit J 7:1-5, 1973. 31. Curley A, Kimbrough R: Chlorinated hydrocarbon insecticides in plasma and milk of pregnant and lactating women. Arch Environ Health 18:156-164, 1969. 32. Kroger M: Insecticide residues in human milk. J Pediatr 80:401-405, 1972. 33. Laug EP, Kunze FM, Prickett CS: Occurrence of DDT in human fat and milk. Arch Industr Hyg Occup Med 3:245-246, 1951. 34. Quinby GE, Armstrong JF, Durham WF: DDT in human milk. Nature 207:726-728, 1965.
Although the general
use
References 1. Pesticide residues in fat: Report of the 1968 Joint Food and Agricultural Organization/World Health Organization meeting. WHO Tech Report, series 417, 1969. 2. Fahim MS, Bennett R, Hall DG: Effect of DDT on the nursing neonate. Nature 228:1222\x=req-\ 1223, 1970. 3. Hayes WJ Jr, Dale WE, Pirkle CI: Evidence of safety of long-term, high, oral doses of DDT for man. Arch Environ Health 22:119-135, 1971. 4. Ecological Effects of Pesticides on Non-target Species. Executive Office of the President, Office of Science and Technology, June, 1971. 5. Report of the Secretary's Commission on Pesticides and Their Relationship to Environmental Health: Part I andII. US Dept of Health, Education, and Welfare, 1969. 6. Ruckelshaus WD: Order Banning General Use of DDT. Environmental Protection Agency, June 14, 1972. 7. Thompson JF: Analysis of Pesticide Residues in Human and Environmental Samples. Perrine Primate and Pesticide Effects Laboratory, Environmental Protection Agency, Research Triangle Park, NC, 1972. 8. Davies JE, Edmundson WF, Schneider NJ, et al: Problems of prevalence of pesticide residues in humans, in Davies JE, Edmundson WF (eds): Epidemiology of DDT. Mount Kisco, NY, Future Publishing Co, 1972. 9. Wilson DJ, Locker DJ, Ritzen CA, et al: DDT concentrations in human milk. Am J Dis Child 125:814-817, 1973. 10. Hoffman WS, Adler H, Fishbein WI, et al: Relation of pesticide concentrations in fat to pathological changes in tissues. Arch Environ Health 15:758-765, 1967. 11. Siyali DS: Polychlorinated biphenyls, hexachlorobenzene, and other organochlorine pesticides in human milk. Med J Aust 2:815-818, 1973. 12. Miller GJ, Fox JA: Chlorinated hydro-
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