Lead Toxicity in Mute Swans

lead.
X-ray.
They were subsequently stored for later re-examination using
Birds were weighed on a 20Kg Salter Spring balance, but if the
plumage was wet or any part of the body was missing, no weight was
taken.
Age was determined by plumage characteristics and beak colour.
X-ray of live birds
Forty one live swans were X-rayed on a C.G.R. Unimax 500 X-ray
machine.
Two X-rays (17cm X 14cm) were taken of each bird on a 'potter
buckey' set at 300 mA, 60Kv for 0.60 sec.
X-rays were stored and
subsequently examined for lead signatures, identified as white spots on
the X-ray film.
Environmental lead
In order to estimate the quantity of lead (other than pellets) in
the environment, grass and water samples were taken at Cork Lough from
January 1985 to Januuary 1986.
Grass samples were dried to a constant
0
weight at 70 C for 24 hours and then digested using 10% nitric acid
as for tissues. Lead levels were determined using a Pye Unicam
graphite furnace as mentioned above.
At Cork Lough, eleven randomly selected stations on the bed were
sampled for discarded lead weights.
2
(0.02m
A total of 200 grab samples
each) were taken and returned to the laboratory, sieved
through 2.8mm and l.4mm sieves (to aid easy examination) and then
examined for lead shot.
At Lough Neagh, grab and core samples (depth
=40cm) of the bed were taken close to where dead birds had been
recovered to establish the distribution and density of lead shot.
2
Kilcolman Wildfowl Refuge, eight replicate quadrats (0.25 m ) were
At
taken and examined for lead shot.
The number of anglers using lead
weights and the time of peak angling was also noted at Cork Lough.
- 64 -
i
y