Lead Toxicity in Mute Swans

Lead poisoned swans
Tests were carried out on six bi'rds·. four Mute
swans,
(
specimen
a b
numbers 978 and 978 are from the same individual with an interval
of one week between collection of specimens), and two Whooper swans
were suffering from acute lead poisoning following the ingestion of
anglers' weights or spent shot-gun pellets. They had kidney and liver
lead levels diagnostic of lead poisoning (Table 7) (see O'Halloran et
al., in press). Biochemical abnormalities were identified by
comparison with the reference distributions given in Tables 1-2 and are
listed in Table 6.
The level of lead in the pancreas was high, while
the levels of lead in the other tissues were variable (Table 7).
All
birds had high blood lead levels and had lost weight, (up to 40% in one
case).
The Mute swans were clearly suffering from hypochromic anaemia,
as values of haemoglobin concentration and mean cell haemoglobin
concentration values approached or were less than the lower reference
limits. The two Whooper swans also had very low haemoglobin
concentrations (Table 6).
On the basis of haematocrit however, some
birds would not be classified as anaemic since three adult males
suffering from lead poisoning had haematocrit values greater than the
lower reference range limit.
Changes in blood chemistry were variable in lead poisoned birds,
with eight biochemical parameters showing deviations from the reference
distribution (Table 6).
Levels of total protein (TP), aspartate amino
transferase (AST), and lactate dehydrogenase (LDH) showed a consistent
pattern of change, with low total protein values and high levels of
plasma enzymes.
Levels of protoporphyrin (PPIX) were high and exceeded
the values of the reference range and the maximum level in 'normal'
swans.
Other parameters ranged above and below the reference
distribution (Table 6).
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