76
and one buzzard (2% of species sample). Another one each of
these species had liver concentrations of 15-20 mg/kg dw. No
individuals of any other species had >15 mg/kg dw, although
some had elevated liver lead concentrations in the range of 6-15
mg/kg dw.
Walker et al. (2012, 2013) reported liver lead concentrations
for a sample of 30 carcasses of sparrowhawks collected in
Britain in 2010 and 30 in 2011. Although one sample had a
lead concentration of 12.6 mg/kg dw which is close to the
threshold for clinical effects, the concentrations in all of the
others were <2 mg/kg. It is unlikely that sparrowhawks will be
frequently exposed to lead gunshot in their prey; it is possible
that occasional exposure may occur in large females that could
feed on pigeons that have been shot and wounded but survive.
While some data are available as described above, the necessary
measurements of tissue lead concentration have not been
reported from sufficient numbers of carcasses of several species
potentially at risk to draw any reliable conclusions about the
proportion of predatory and scavenging birds dying from
lead poisoning in the UK. In particular, sufficient observations
are lacking for white-tailed eagle, golden eagle and western
marsh harrier. It should also be noted that the geographical
distribution within the UK of the locations from which carcasses
of scavenging and predatory birds were collected and sent for
analysis is likely to be atypical of the distribution of the species
as a whole for some of the species with potentially high risks
of exposure to ammunition-derived lead. In particular, the
collection of carcasses of buzzard, golden eagle and white-
tailed eagle from areas in which large numbers of red deer are
culled and viscera discarded is probably infrequent relative to
the proportion of the population of these species in such areas.
Carcasses are usually collected by members of the public, and
areas with high levels of culling of deer tend to be remote from
human populations.
There is strongevidence that a sometimes substantial proportion
of predatory and scavenging birds die from lead poisoning from
studies in North America and Europe (see earlier sections of
this paper). The small numbers of samples of raptor carcasses
collected from largely lowland England suggest that exposure
is likely in a small proportion of individuals of those species that
would be predicted to be at risk from their feeding ecology.
Studies on red kites show that risks may vary locally. There has
been little research in the UK on some of the potentially most
at risk species (e.g. white-tailed and golden eagles, and marsh
harriers) and in those areas (e.g. upland deer shooting areas and
coastal areas) where the risks are likely to be most significant.
However, source, pathway, receptor links clearly exists for these
species and further research is required.
Few studies have been conducted on the possible impacts of
ammunition derived lead in carnivorous mammals, but those
that have show little evidence for direct poisoning. Rogers et
al. (2012) reported that blood lead levels of grizzly bears Ursus
arctos in the Greater Yellowstone Ecosystem, USA, were not
appreciably higher during the hunting season, despite the
presence of carcasses and discarded viscera of deer during the
hunting season. In addition, they found that lead concentrations
in blood and tissues of wolves Canis lupus and mountain lions
Puma concolor in the region were low. Hence, in this region
there was no evidence that ingestion of lead from hunter-killed
carcasses or viscera was leading to the absorption of lead by
thesemammalian carnivores. Similarly, Millán et al. (2008) found
relatively low levels of lead in liver, muscle and bone in five
species of carnivorous mammals in Spain.
EFFECTS OF AMMUNITION DERIVED LEAD ONWILDLIFE
FOLLOWING INGESTION OF LEAD CONTAMINATED
SOIL, WATER AND BIOTA (EXPOSURE ROUTE 3)
There appear to be substantial inter-specific differences in
the tolerance of invertebrates to lead of ammunition origin
in soils and water. At a cast-off shooting range in Finland,
Rantalainen et al. (2006) found microbes and enchytraeid
worms to be negatively affected by the contamination while
soil-dwelling nematodes and microarthropods appeared
unaffected. Migliorini et al. (2004) found the abundance of
Collembola, Protura and Diplura to be positively correlated
with major detected contaminants (lead and antimony) in soils
from a clay pigeon shooting range, while Symphyla showed a
negative correlation with these pollutants. Concentrations of
lead in the saprophagous Armadillidium sordidum (Isopoda)
and the predatory Ocypus olens (Coleoptera) increased with
the soluble lead fraction in soil, showing that a significant
portion of metallic lead from spent pellets is bioavailable in
the soil and can be bioaccumulated by soil organisms. Reid
and Watson (2005) found soil levels of 6,410 +/- 2,250 and 296
+/- 98 mg(Pb)/kg dw, respectively at a clay-pigeon shooting
site soil and an un-shot control site. At 6.1 +/- 1.2 mg(Pb)/g dw,
shooting site body burdens of earthworms Aporrectodea rosea
were almost 1,000 times higher than those from the control site
Deborah J. Pain, Ruth Cromie & Rhys E. Green