European Journal of Scientific Research - EuroJournals

350 E.A. Moses, J.C. Akan, V.O. Ogugbuaja and P.A. Onyeyili
samples were centrifuged after collection at 2000rpm for ten minutes to obtain serum. Serum samples
were stored in plastic vials at -20ºC prior to elemental analyses.
Determination of Elements in Serum Samples
One millilitre of serum was diluted to 10 millilitres with de-ionized water. Determinations for Cr and
Zn were made on each solution, using Flame Atomic Absorption spectrometer (Model UNICAM 969).
The results of each sample were the average of three sequential readings.
Tissue Kinetics
Thirty adult Sahel goats of both sexes were used for the study. The goats were apparently healthy at the
onset of the experiment. They were divided randomly into two groups of fifteen goats each. One of the
groups was treated with 50mg/kg body weight of dust sample intravenously while the other group was
treated with the same dose of dust sample intratracheally.
Post-mortem Studies
Three goats were sacrificed at 3, 7, 14, 21, and 28 days post inoculation. Tissue samples (liver, kidney,
lungs and heart) were taken at each of the periods. Tissue samples were oven dried at 40ºC, ashed and
then analyzed for Cd and Zn using Atomic Absorption Spectroscopic technique as described by
Ogugbuaja (1984). Three goats served as control and were used to prepare tissue standards.
Calculation of Kinetic constants
Linear regression analyses were performed on the semi-logarithmic plot of mean elemental
concentrations against times for blood and tissues. And the slope of elimination curves determined.
The elimination half-life (t1/2) was then calculated using the formula
t1/2 = 0.693/k where k = elimination rate constant
Results
Concentration - time curve for serum chromium and zinc are shown in Figure.1 and 2. Mean cadmium
serum concentration of 5.10.±0.11µg/ml and 7.21±0.10µg/ml were respectively obtained for
intratracheally and intravenously treated goats at two hours post exposure. Thereafter, there was a
steady decline in serum chromium concentration to 1.17±0.06µg/ml and 0.31±0.03µg/ml after 18 hours
post exposure. By the thirty-sixth hour, chromium concentrations reduced to non-detectable levels in
intratracheally treated goats. A mean zinc serum concentration of 2.88±0.11 µg/ml was obtained 15
minutes post intravenous dust administration. This was followed by a constant decrease in serum zinc
concentration. Fifteen minutes after intratracheal dust administration, the serum concentration was
observed to be 1.62±0.33 µg/ml. An increase in serum concentration was observed until a peak
concentration of 2.13±0.13 µg/ml was recorded at 2 hours post dust administration. The concentration
thereafter decreased to 0.33±0.04 µg/ml after 36 hours.