Lead Toxicity in Mute Swans

area of 4m 2 , were taken. The samples were bagged and returned
to the laboratory, sieved through 2.8mm and 1.4mm sieves
respectively and subsequently examined for lead shot.
(2) A lm dredge was dragged 50m along the bed of The Lough, the
contents of the dredge were sieved as previously described and
examined for lead shot.
Five lOml water samples were taken from The Lough, Cork City
and lead content was estimated on a Perkin Elmer 2380 atomic
absorption spectrophotometer in the flameless atomising mode with a
wavelength of 2 l 7nm.
Standard statistical analysis was applied to the data. Means and
standard deviations were calculated on a desk top calculator. For
comparison or blood lead levels and data was logarithmically
transformed to compare using a Students-T-test.
Results
Weight of swans sampled
At the various sites the mean weight of the live birds varied little.
(Table l, Fig. 2). The weights of the two dead birds were lower with
the weight of the lead poisoned bird particularly low.
Movements of Birds during Study Period
No movement of birds from the River Lee to The Lough was
recorded. However, dye marked birds at The Lough were recorded on
the Lee. The number of birds marked at The Lough and observed on
the Lee varied daily, with a maximum of eight on one occasion.
However, on most occasions only single birds were recorded. No
movement of dyed birds from othe~ sites was recorded.
Table 1
Mute Swan Body WJt. (k1)
Sample
ALIVE
Location Lough Lee Others
DEAD
Number 104 11 7 2
Range 4.5-12 7-12 7.5-13.5 (5) & (7)
Mean 9.23 9.27 10.2 -
S.D. + 1.4 + 1.4 ±1.97
138 -
. ' ........