Acta Pzdiatr Scand 65: 535-539, 1976

INSECTICIDES IN HUMAN BREAST MILK ARNE F. BAKKEN and MARTIN SEIP From the Department of Paediatrics, Rikshospitalet, University of Oslo, Oslo, Norway

ABSTRACT. Bakken, A. F. and Seip, M. (Department of Paediatrics, Rikshospitalet, University of Oslo, Oslo, Norway). Insecticides in human breast milk. Acta Paediatr Scand, 65: 535, 1976.-Fifty samples of human breast milk were analysed by gas chromatography and thin layer chromatography for DDT (dichlordiphenyltrichloraethan), hexachloroben201, benezene-hexachlorides, dieldrin, aldrin and heptachlorepoxide. The three first substances were found in all samples in amounts varying from quite small up to eleven times the WHO recommended maximum for cow milk. The other substances were found in fewer milk samples, however, in some of these samples they were found in relatively high amounts. In Norway, only DDT has been investigated earlier (4), and compared to that study, there has been no significant change in the mean concentration of DDT in human breast milk during the last five years. The insecticide content was highest in colostrum and decreased with increasing duration of lactation. Considerable fluctuations in the content of insecticides were recorded in repeated milk samples collected from the same woman a few days apart. The percentage of samples with insecticide content higher than that permitted for cow's milk was greater in May/June (79%) than in early April (54%). The significance of these findings is discussed.

KEY WORDS: Insecticides, human breast milk

The presence of small amounts of insecticides in human breast milk has been known for a considerable period of time (4,5 , 8, 13, 17). The chlorinated hydrocarbons, HCB, BHC, DDT and its metabolite DDE, Dieldrin, Aldrin and heptachlorepoxide are most often mentioned in the literature. Even if the problem has been given attention in the Scandinavian countries (2, 3, 4, 17), the topic has been little discussed among paediatricians. The general problem of the susceptibility of fetus and child to chemical pollutants was discussed lately (15), although only a few publications known to us have described the actual amount of insecticides in tissues from infants (1, 6). This study was performed to investigate the content of insecticides in human breast milk in Norway and to get an impression of The analyses were kindly performed by NestlC's laboratories in Copenhagen, Denmark.

whether the official prohibition of these insecticides in Norway (Dieldrin and Aldrin from 1965, the rest from 1970), has influenced the human milk level. Furthermore, the amount of insecticides in human milk at different time intervals from the birth of the infant was studied. Lastly, in three cases repeated samples were collected some days apart from the same woman to see if the daily intake of insecticides could possibly be reflected in the milk. MATERIALS AND METHODS Fifty samples of human breast milk were collected in quantities of 100 ml. Three women gave more than one sample. The milk was collected from different hospitals in the Oslo urban region, except that four samples came from Hallingdal-a valley in the central part of Southern Norway. The samples were frozen to minus 20°C in plastic containers and later analysed by gas chromatography and thin layer chromatography' (1 1). The fat content of the milk was not determined. None of the women were subject to occupational exposure to insecticides. Acta Piediatr Scand 65

536

A . F. Bakken and M . Seip

Table 1. Concentrations of insecticides in 50 samples of human breast milk

Compound HCB a-BHC P-BHC y-BHC 6-BHC Total BHC Heptachlorepoxide 0 . p . ' DDE p.p.'DDE 0.p.' DDT p.p.' DDT Total DDT (DDE+DDT) Aldrin Dieldrin

Number of positive samples

Range of concentrations

Mean values

(partsper billion)

50 17 49 17 34 50

1,21.00.31,7-

1.7- 60.5

45.5

9.70 0.58 4.69 10.91 1.14 9.44

18 30 50 49 50

0.6- 2.6 1.6- 43.8 0.%113.2 1.6- 120.9 2.3-138.3

1.57 18.02 65.10 18.53 17.89

SO 1 6

5.2-349.0 21.8 0.3- 3.6

81.74 21.8 2.75

0.1-

1.9

17.8 35.8 3.2

Abbreviations and nomenclature: HCB =Hexachlorobenzol BHC =Benzenehexachloride=HCH=Hexachlorocyclohexane a-BHC =Benzene (trans) hexachloride P-BHC =Benzene (cis) hexachloride y-BHC =Benzene y-hexachloride=Lindan=Gammexane 6-BHC =Benzene 6-hexachloride DDT = I,l,l,-Trichlor-2,2-bis (4-chlorphenyl) aethan=Dichlordiphenyltrichloraethan DDE = 1,l-Dichlor-2,?-bis (4 chlorphenyl) -aethyp.p7-

, len=Dichlordiphenyldichloraethylen parapara =

0.p' Dieldrin

=ortho para =H.E.O.D. =Hexachloro epoxy octahydro dimethanonaphtalene Aldrin and Heptachlorepoxide are closely related to Dieldrin. Ail the substances mentioned are called insecticides of the chlorinated hydrocarbonic type. (r plus p plus y plus 6-BHC is called total BHC. plus DDE is called total DDT.

MT

RESULTS All milk samples contained HCB, one or more types of BHC, DDT and DDE. The other types of insecticides were found in varying numbers of the samples. Table 1 shows the overall results of the study. The number of positive samples for each type of insecticide, the range of the concentrations given as ppb (parts per billion), and the mean values of the concentrations are given. If one considers the maximum concentration for cow's milk approved by the World Health Organization (WHO) (18), 7 of the samples contained amounts of HCB above this value of 20 ppb, 28 samples contained BHC at a concentration above the approved value of 4 ppb, and 36 of the milk samples had a concentration of total DDT (DDE+DDT) above the maximum approved limit of 50 ppb. If the maximum advisable daily intake (ADI) for total DDT of 0.005 mg per kg per day (18) is calculated for a 5 kg baby, 46 out of the 50 samples contained more DDT than approved by WHO for _ cow's milk. The results from Hallingdal are not specifically stated, as there was no difference in the results between these samples and the milk samples collected in Oslo. Table 2 shows the results of the three most important groups of insecticides, HCB, BHC and DDT, in milk collected at varying time intervals after the birth of the baby. The values are higher in the co~ostrum,thereafter decreasing. To give an impression of the great varia-

Table 2. Concentration of insecticides in human breast milk at different times after the birth of the infant All values as means fS.D. in ppb Compound HCB (20)" Total BHC (4)" Total DDT (SO)" (DDT+DDE)

"

Colostrum 15 samples

1 4 weeks 16 samples

5-8 weeks 9 samples

7.75 1.4 12.8k 4.6

8.2f 3.5 9.3f 2.3

5.9f 1.9 6.3f 1.6

94.02 2 1.4

84.1f24.8

71.6f16.5

9-16 weeks 6 samples 10.0+ 2.8 6.8f 1.3 55.6f 19.5

Values in parenthesis are maximum allowed concentration as ppb in cow's milk approved by WHO.

Acta Pzdirtrr Scand 65

Insecticides in human breast milk pPb (par(s per bh'lOn .Mean values for each group 150*

1oa

.. I.

50..

*.

*

I

.

... '

a.

. . .c ..

bility of the DDT content, Fig. 1 shows all values of total DDT. The number of samples with relatively high insecticide content (above 50 ppb) was greater in May/June, 79%, than in early April, 54 %. However, the difference of the total mean values was not statistically significant. Fig. 2 shows the amount of HCB, total BHC and total DDT in milk samples collected from the same women some days apart. The one woman who gave four samples has great fluctuations of the insecticide content in her milk, total BHC varying from 10 ppb down to 3.8 ppb, increasing later to 5.9 ppb. The other two women who gave two samples also show great fluctuations. Total BHC in the milk from one of the women increased more than four times during four days from 8.6 to 40.8 ppb.

HCH, 28 for BHC, and 36 for DDT (when the AD1 value is calculated for a 5 kg infant, 46 out of the 50 samples exceeded that limit). One sample contained as much as 349 ppb of DDT. Compared to the AD1 value for DDT for a S kg baby of 0.003 mg per day, that particular milk sample contained between 1 1 and 12 times the DDT amount approved by WHO for cow's milk. Compared to earlier studies of insecticides in human breast milk in the Scandinavian countries (4, 17) our results show about the same overall level of DDT and cr BHC. The other parameters were not studied before. There has been no significant change in the mean total DDT content of human milk in Norway since 1970, when DDT was officially prohibited (4). Compared to Western Germany (14) the mean content of DDT is lower in Norway, 81.7 ppb vs. 107 ppb, and so is the mean content of HCB, 9.7 ppb vs. 29 ppb. y B H C or Lindane shows about the same values in Western Germany and Norway, 12 ppb vs. 10.9 ppb. One interesting point is the high amount of pp' DDE, being a degradation product of pp' DDT. pp' DDE is found in about the same concentration in Norway and Western Germany, and in much higher amounts than pp' DDT. This may be due to the great stability of pp' DDE in nature. In addition to the great stability of insecticides in nature (2). there may be other factors contributing to the relatively high concen-

--

-Total DOT HCB H Total BHC rnparts p*rb,lln"

DISCUSSION All SO samples of human breast milk contained small amounts of insecticides. HCB, BHC and DDT were found in all samples studied, while heptachlorepoxide was found in 18 out of SO samples, and dieldrin and aldrin were found in 16 samples and 1 sample, respectively. More important are the relatively high concentrations found in relation to the AD1 values for cow's Inilk: recommended by samples were higher in concentration for

537

11 p 1.

200 20

100

ia

/

* # A + :

LN

5th

9th June

6th

9th June

25th

20th May

30th

zn,j June

Fig. 2 . Total DDT, HCB and total BHC in repeated samples of human breast milk from three individuals. The samples were collected some days apart as indicated. Acta Pzdiatr Scand 65

538

A . F. Bakken and M . Seip

trations we still find in human breast milk. The substances may be used illegally. Furthermore, there are exceptions in the law, such as the possibility of using DDT for forestry, BHC for cleaning flour-mills of moths, and the use of Dieldrin and Aldrin in the clothing industry and for special wooden constructions and prefabricated houses (9). The concentration of insecticides in human breast milk decreases from colostrum onward (Table 2 ) . The lower content of fat in the milk one month after the infant is born compared to colostrum (16) may explain part, but not a11 of this decrease. It has betn stated that the content of insecticide in the mature milk is relatively independent of the f t content (14). The liberation of insecticides ound in body fat is probably greater in the beginning of the milk-producing period. The DDT content in body fat has been found to be thirty times the average content in human breast milk ( 5 ) . One may assume that part of the insecticides is less tightly bound to the body fat, and hence is given away to the breast milk at the beginning of the lactating period. In addition to what is released from the body fat must be added the amount of insecticides absorbed from food consumed by the mother in that period. In contrast to the assumption of Quinby et al. (13), we found considerable fluctuations in the concentration of insecticides in repeated milk samples collected from the same woman a few days apart (Fig. 2). Trying to explain these fluctuations one must consider two pools of insecticides in the body: one in the adipose tissue, and one in the blood/milk phase. It is conceivable that variations in the dietary intake of insecticides can explain, at least partly, the day-to-day fluctuations in insecticide concentration, iince the mobilization of insecticides from the pool in adipose tissue presumably is more stable. As already mentioned the number of samples with relatively high insecticide content was considerably greater in May/June than in early April. This might be related to

\

Actu Pirdiurr Scund 65

greater consumption by the mothers of imported fruits and vegetables in the late winter and spring. However, to confirm this assumption would require further investigation. Hitherto there is no positive evidence that the presence of insecticides in human breast milk does any harm to the infants. However, from our study it is obvious that at least some infants will get much higher doses of for example DDT than adults. The infant of the mother having 349 ppb DDT in her milk will get ten times more DDT per day than is stated as the highest advisable amount for adults. There is no danger of acute intoxication with these amounts. A single dose of 10 mg DDT per kg body weight will give acute poisoning in adult man (13). An average Norwegian infant on breast feeding will get only one thousandth of this dose per day. The question whether harmful long-term effects may occur is a more serious one, and cannot be answered with certainty. For instance, it is known that DDT induces the cytocrome P,,, (12, 20), and that DDT also may be carcinogenic (20). The facts that breast feeding is carried out over a relatively short period of life only, and that no harmful effects have been observed, may be reassuring. However, the breast fed infant is in a period of rapid growth and development, which may increase his susceptibility to toxic substances. The fetus also is exposed to insecticides. DDT and other insecticides are transmitted from the mother to the fetus through the placental barrier, and have been demonstrated in adipose tissue from stillborn infants ( 1 , 6). In one study from Great Britain ( I ) , the mean content of total DDT in adipose tissue at birth was found to be about one third the content in adipose tissue from adults, and it did not increase during the first year of life. With our present knowledge we feel that paediatricians should continue to encourage breast feeding, since it has so many wellknown advantages. But as paediatricians we should be well aware of the possibility of pollution of breast milk with toxic substances

Insecticides in human breast milk and convey a warning to the political authorities against indiscriminate use of poisons which may appear in the milk. The quality Of the breast milk should be under regular observation and control. On the other hand, a worldwide prohibition of these insecticides will be unrealistic as long as they play a very important role in the campaign against malaria and other vectorborne diseases (19). These problems are a constant dilemma in the world household (7, 10).

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REFERENCES 1. Abbott, D. C., Goulding, R. & Tatton, J. OG.: Organochlorine pesticide residues in human fat in Great Britain. Br Med J , I l l : 146, 1968. 2. Aksnes, G.: Giftene vi gir naturen. Universitetsforlaget, Oslo, Bergen and Tromsn 1968. 3. Barstad, J. A . B.: Noen milj~toxikologiskerefleksjoner med utgangspunkt i PBC og andre persistente klorerte hydrokarboner. Tid.\slr N o r Lzgeforen, 95: 618, 1975. 4. Bjerk, J. E.: Rester av DDT og polyklorerte bifenyler i norsk humant rnateriale. Tidsshr Nor Lzgeforen, 92: 15, 1972. 5. Egan, H . , Goulding, R., Roburn, J. & Tatton, O G . J.: Organichloride pesticide residues in human fat and human milk. Br Med J , IZ: 66, 1965. 6. Engst, R., Knoll, R. & Nickel, B.: Uber das Vorkommen von DDT und DDE im Fettgewebe und in Organen von Kleinstkindern. Pharmazie 24: 673, 1969. 7. Hammond, A . L.: Chemical pollutions: polychlorinated biphenyls. Science, 175: 155, 1972. 8. Martin, H.: Guide to chemicals used in crop protection. Canada Department of Agriculture, Toronto 1961,4th ed., p. 18.

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9. Mehl, R.: Personal communication from Department of Milieu Toxicology, Norwegian Institute of Public Health. 10. Nature, Editorial,240:319, 1972. 11. Noren, K. & Westoo, G.: Determination of some chlorinated pesticides in vegetable oils, margarine, butter, milk, eggs, meat and fish by gas chromatography and thin layer chromatography. Acta Chem Scand, 22: 2289, 1968. 12. OBrien, R. D.: Insecticides. Action and metabolism. Academic Press, New York and London 1967. 13. Quinby, G. H . , Armstrong, J. F. & Durham, W. F.: DDT in human milk. Nature, 207: 726, 1965. 14. Rappl, A. & Waiblinger, W.: Zur Kontamination von Muttermilch mit Riickstanden chlonerter Kohlenwasserstoffe. Dtsch Med Wochmschr, 100: 228, 1975. 15. Sandifer, S. H.: Industrial and agricultural chemicals. In The susceptibility of the fetus and child to chemical pollutants. Pediatrics, 53: Supplement 5 : 843, 1974. 16. Statens ernzringsrid, Naeringsmiddeltabell. Landsforeningen for kosthold og helse. Oslo 1974, 3rd ed. 17. Wetsoo, G., Norin, K. & Anderson, M.: Klorpesticid och polyklorbifenylhalter i margarin, matoljor och vissa animaliska livsmedel i svensk handel hren 1967-1969. Vdrfiidu. 2-3:9, 1970. 18. WHO: Pesticide residues in food. Technical report series nu. 417, Geneva 1969. 19. WHO: The plrrce of DDT in operation against muluriu and other vector-borne diseases. Official record no. 176, Geneva 1971. 20. Wurster, C. F.: More about DDT. JAMA, 231:463, 1975.

Submitted Nov. 27, 1975 Accepted Jan. 17, 1976 (A. F. B . ) Department of Paediatrics Rikshospitalet Oslo Norway

A d a Pzdiarr Scand 65

Insecticides in human breast milk.

Acta Pzdiatr Scand 65: 535-539, 1976 INSECTICIDES IN HUMAN BREAST MILK ARNE F. BAKKEN and MARTIN SEIP From the Department of Paediatrics, Rikshospita...
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