Trends Of Residue Levels In Human Milk Over Time

There is a downward trend in residues of polyhalogenated aromatic hydrocarbons tobe observed in industrialised countries.

Figures 3 and 4 show the German observations for mean concentrations of PCB and two pesticides since 1980 and for dioxins in human milk samples since 1985.

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998

year

Figure 3. Trends for mean concentrations of PCB, DDT and HCB in human milk in Germany

1980 1982 1984 1986 1988 1990 1992 1994 1996 1998

year

Figure 3. Trends for mean concentrations of PCB, DDT and HCB in human milk in Germany

year

Figure 4. Trend for mean dioxin levels in human milk in Germany (n=2188)

year

Figure 4. Trend for mean dioxin levels in human milk in Germany (n=2188)

Table 9 shows the percentage decreases from 1979/81, from 1987 and from 1993 until 1997 in human milk samples in Germany. It should be pointed out that there is a 30% decrease in mean PCB levels since 1992, when the intake ofinfants into the Dutch PCB/Dioxin Study (see Boersma, this volume) stopped. Conclusions that have been drawn from that study and will be drawn from future follow-up, therefore, are no longer applicable to the present levels of exposure.

Table 9. Decrease in average residue levels (in %) in human milk in Germany

from

to

ß-HCH

HCB

total DDT

total PCB

1979/81

1997

87.8

93.5

82.8

71.1

1987

1997

62.1

79.1

57.8

51.3

1993

1997

19.7

48.6

28.5

31.7

(total number of samples analysed: >38 000)

(total number of samples analysed: >38 000)

German authors 31 have been able to confirm the decrease of environmental/dietary exposure to PCBs in adipose tissue biopsies from 3 year old children since 1985: median levels decreasedby 86% until 1995.

Apparently strict regulation of these compounds is successful. For the future these restrictions have to be continued and, hopefully, will be combined with measures to prevent prospectively the accumulation of "new" substances with similar properties in the food chain and thereby appearing in human milk. Accumulation, once a fact is difficult to undo by individual and especially short-term measures, e.g. selective dietary choices in women planning to become pregnant. However, lifelong adherence to dietary recommendations of nutritional societies to increase the intake of plant protein to 50% of total protein intake, to prefer low-fat food from animal origin and to increase the intake of plant oils will automatically decrease the intake of polyhalogenated aromatic hydrocarbons.

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