Lead Toxicity in Mute Swans

for corrected lead values (ug /g Rb).
Specimen D (Table 1) was a two
month old cygnet.
Blood lead level was low and gradually increased with
age until at some time between day 14 and 21, the cygnet ingested a lead
weight after which it dramatically increased.
Specimen E sampled three
times in 63 days had low lead levels.
The range of blood lead values from Mute swans at Cork Lough was
considerable, being from 0.46 to 106.30 ugPb/ gHb (0.30 -
66.00 umoles/L
n = 823) with a seasonal trend in the pattern of elevated lead levels.
Seasonal Variation
Blood lead levels corrected for haemoglobin in swans from Cork Lough
is presented in Fig. 3.
There was no difference in the proportion of
birds with elevated lead for the individual sex or age class, thus the
pattern for the total population is presented.
The proportion of birds
with elevated blood lead levels (3.00 ug/ gHb) was highest in winter (
63% and 66%) and spring (43% and 73.50%) and lower in summer (31% and
31%) and autumn (48% and 22%). The median lead levels were highest in
the winter and spring months (Fig. 3).
There was no change in the
observed pattern for corrected or uncorrected blood lead levels in the
flock birds.
Moulting birds.
A number of birds were sampled before and after moulting and lead
levels are presented in Table 2.
Blood lead levels were always lower
during primary moult than at any other time.
In some instances (e.g.
specimen E) the blood lead value returned to its former elevated level.
Moulting birds sampled at Macroom Co.Cork had very low blood levels
(median= b.84ug Pb/ gHb, range = 0.25 -
2.00ug Pb/ gHb, n = 24) with no
birds showing elevated lead levels.
Similarly, at Cork Lough, adult
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