| dc.description.abstract | A survey of the literature revealed that livestock
production ranks second to cereals, provides employment and
helps in alleviating poverty especially in the rural areas
of Western Kenya; that a number of acaricides are available
of which Steladone 300EC is the most commonly used for the
control of tick-borne diseases such as East Coast Fever in
grazing cattle in the area; that chronic or acute exposure
to these acaricides can have serious health effects on man;
and that no comprehensive research had been carried out
determine the fate and potential accumulation of these
chemicals in cows' milk.
A study was therefore conducted in which one hundred
samples of cows' milk were collected from individual farms
and several delivery centres in the districts of Bungoma
and Trans Nzoia in Western Kenya at different periods of the
year. The objective was to determine the fate and residual
effect of chlorfenvinphos, the active ingradient in
Steladone 300EC, as affected by season, butterfat content
and method of acaricide application (whether by dipping or
hand spraying).
Samples.were subjected to 'chlorfenvinphos analysis by'
high pressure liquid chromatography and a combined gas
chromatography mass spectometric technique following the
mandatory li9uid extraction and clean-up operations. Results
were based on butterfat content which was determined
gravimetrically after 'extraction into hexane.
Concentrations of chlorfenvinphos varied between 0.52
and 3.90 pg/kg in the dry season; and from 1.58 to 10.96
g/kg in the samples collected during the wet season. Dipped
cows gave milk which was significantly higher (P<0.05) in
the acaricide content than hand-sprayed animals. The
chlorfenvinphos degradation product, 2,4-
dichloroacetophenone was detected in only 12 % of the
samples, at concentrations ranging from 3 276 ~g/kg.
Concentrations of both the acaricide and it's metabolite
were positively correlated with the content of butterfat in
the milk.
Reference to the 1993 Codex Alimentarius showed that
the acaricide residue concentrations all fell below the
recommended critical level of 8 ug/kg, suggesting that
health risks arising from dietary exposure by the adult
residents in the study area may not be serious. However, for
infants, the danger may be significant since the accepted
daily intake was exceeded by between 7 - 15 times.
It is suggested that monitoring programes be initiated
to generate data on pesticide residues on a regular basis.
Educational programmes to sensitize the farm-workers and
dip manangers on the hazards posed by poor acaricide
handling and careless spillages will be an added advantage.
Nursing mothers should be encouraged whenever possible to breastfeed their young to reduce exposure to acaricides
through intake of cow's milk. | en |
