| dc.description.abstract | Human milk samples were collected from eight areas in Kenya
with different agricultural activities. All the mothers had
lived within the area for the last five years. They were
healthy and breast feeding their first or second child. In 264
mothers milk samples analysed, 13 organochlorine pesticide
residues were detected in the following order of frequency:
p,p'-DDT (100%), p,p'-DDE (100%), BCB (60%), aldrin (35%),
lindane (30%), P-HCH (27%), dieldrin (20%), o(.,-HCH(8%),
transnonaclllor (6%), heptachlor (4%), endrin (4%), heptachlorepoxide
(0.4%), and oxychlordane (0.4%). No residues of PCBs
were found. Great regional differences in the levels of these
compounds were found; and the mean levels of sum DDT ranged
from 1.69 mg/kg in milk fat of nomads from Loitokitok to 18.73
mg/kg milk fat in human milk from Rusinga Island. Regional
differences were also found in the mean ratio of p,p'-DDT to
its more persistent metabolite p,p'-DDE, with mean levels
ranging from 0.7 in Karatina to 4.4 in Turkana. Similarly, the
results demonstrated significant differences (P<0.05) in the
mean levels of sum DDT and the ratio of p,p'-DDT to p,p'-DDE
within the various sampling area depending on the agricultural
activities. The results demonstrate large contamination of
Kenyan human milk with organochlorine pesticides, especially
DDT and DDE. The levels of sum DDT obtained were higher than
corresponding levels reported from industrialized countries,
and the estimated daily intake of a Kenyan infant exceeded the
Acceptable Daily Intake set by the WHO/FAO. There was also a
positive correlation of sum DDT, and P,P'-DDT to P,P'-DDE ratio
with the mother's age. The results were also examined in
relation to differences in living conditions with regard to
agricultural activities, dietary habits, and reported use of
pesticides in the various sampling areas.
Examination of commercial infant milk formulas on the Kenyan
market revealed that only one contained organochlorine
pesticides, and the levels were low, being 0.05 mg DDE/kg milk
fat and 0.06 mg dieldrin/kg milk fat.
The time trend (1983-84) in DDT contamination in Turkana
where DDT was extensively used in cotton growing, was also
investigated. The changing from growing cotton to food crops
within 9 months was followed by a reduction in the mean level
of sum DDT f roru 7.79 to 4.49 mg/kg milk fat.
Human food samples were examined for organochlorine
pesticides in order to determine the sources of these compounds
in the human body. Of the 243 food samples examined, about 50%
of them contained at least one organochlorine residue, but
generally the levels were low. The DDT-group was most commonly
found in fish, cow's milk, vegetables and cereals. Lindane had
a high incidence of occurrence in all the food s~mples examined.
Other organochlorines detected were aldrin, a!-HCH, P-HCH
transnonachlor, oxychlordane, dieldrin. PCBs were not detected.
The mean sum DDT found in fish was 128 ug/kg and p,p'-DDE was
the major metabolite.
The dietary intake of the different organochlorines
through food samples varied in the different areas. The occurrence
of pesticide residues in food appeared to be closely
associated with the use of similar pesticides in the area.
Foods of animal origin contained higher levels of the DDT group
as compared to other food groups in all areas. In general, a
mothers daily intake of sum DDT was lower than the infants
daily intake of sum DDT through breastfeeding, which demonstrates
mobilization and excretion of stored pesticides in the
mothers milk.
Samples of maternal blood, milk, subcutaneous fat, as well
as umbilical cord blood were collected from mothers and their
infants at Kenyatta National Hospital. The mothers were healthy
but delivered by Cuesarean operation. In the 41 samples analysed,
the DDT-group occurred in all, dieldrin ill 11, transnonachlor
in 6, J-HCH in 5, endrin in 2 and lindane in 1. The
mean levels (mg/kg fat) of sum DDT were 5.91 in subcutaneous
fat, 4.86 in mothers milk, 2.75 in maternal serum and 1.87 in
umbilical cord serum. J -HeH was only found in subcutaneous fat
and milk with mean levels of 0.034 and 0.26 mg/kg fat, respectively.
Dieldrin, endrin, and transnonachlor were detected in
maternal ser~m but not in umbilical cord serum. Dieldrin
detected in mothers milk and subcutaneous fat could not be
quantified. There was a significant correlation between the
levels of sum DDT in subcutaneous fat and milk fat (r=0.963),
subcutaneous fat and maternal serum fat (r=O.843), and maternal
serum fat and maternal milk fat (r=0.868), indicating the
coherellce of DDT in the body and demonstrates that human milk
is a suitable indicator of monitoring organochlorine contaminants
in the human body. | en |
