Lead Toxicity in Mute Swans

RESULTS
Blood Lead Levels
Diel variation:
Caged birds: During the day (10.00-16.00 hrs), samples taken from caged
birds showed variation in haematocrit, haemoglobin and blood lead both
in individual birds and between birds (Fig.2A and 2B).
Haemoglobin
varied less than haematocrit, so blood lead values were corrected for
haemoglobin.
Corrected lead values were less variable than the
uncorrected values (Fig. 2A, 2B).
At night (16.00-07.00), haematocrit, haemoglobin and blood lead
varied considerably with no pattern emerging irrespective of the degree
of light exposure (false day or false night) (Fig.2C and Fig.2D).
Blood
lead levels were corrected for as above (Fig 2C, 2D).
Wild birds:
Two birds sampled at intervals of 6 hours in the field
showed similiar patterns to caged birds.
There were no differences in
the values of blood lead corrected for haemoglobin for the two birds
examined.
One swan (specimen A, Table 1) showed very little variation in the
blood lead level over the period sampled.
A second swan (specimen B
Table 1) ingested a lead weight on or about day 7 and the blood lead
level did not reach its maximum concentration until 28 days after
ingestion.
The blood lead level dropped within 14 days of this maximum
value.
A third swan, (specimen C, Table 1) had ingested at least one
lead weight on or before the first sampling date and had a maximum
concentration on day 21.
Although the blood lead concentration
(umoles/L) on day 147 is less than on day 84 the opposite is the case
- 23 -