Has sheep wool got potential as a biomonitoring device for heavy metal concentrations in the UK upla

1
Has sheep wool got potential as a bio-monitoring
device for heavy metal concentrations in the UK
uplands? J.C. Sneddon M Powell Liverpool John
Moores University j.c.sneddon_at_ljmu.ac.uk
Introduction Methods Upland sheep in the UK
often graze on land containing naturally high
concentrations of heavy metals. This pilot trial
set out to assess the potential of wool matrix as
a bio-indicator of farm heavy metal concentration
in North Wales Cumbria. A questionnaire
administered via the Rare Breeds Survival Trust
produced wool samples from 12 farm-bred and
mainly rare breeds of sheep from 15 farms (Table
1 Plates 2a, b). Wool was washed according to an
established protocol (Plates 1a, b). Copper and
lead concentrations in the wool matrix (ng.g-1)
were obtained by ICP-MS (n3 repeated
measures/sample 3 total measured samples 720).
The British Geological Survey G-BASE data base
was employed to correlate wool element
concentrations with stream sediment
concentrations for elements in the farm
localities (Plates 2 a, b). OS 4 digit grid
references were used to locate farms based on
their holding numbers, and the stream sediments
had been mapped on a 2x2 km grid square.
Plate 2 a,b. G-BASE maps for stream sediment
concentrations for Pb Cu with superimposed farm
locations coded for wool element concentrations
Table 1. Data on experimental subjects in the
study
Results Discussion
Significant associations between wool and stream
sediment concentrations were found for copper (?2
6.32 plt0.04 df2) and lead (?2 193.18
plt0.001 df2) n 720. Between-individual
variation in wool element concentration was 2.5
times higher for copper than for lead indicating
differences in metabolic bioavailability or
environmental sources of variation. There were
significant effects of breed for both wool copper
(?2 132.85 plt0.001 df11) and wool lead (?2
264.95 plt0.001 df11). Llanwenog had higher
median copper concentration in a low Cu area and
Shetland lower median lead concentration in an
intermediate Pb area than other breeds (plt0.05) .
North Ronaldsay had high median copper
concentrations in an intermediate Cu area. This
technique could be used to indicate where N.
Ronaldsay sheep could be at risk from copper
toxicity in view of their unique copper
metabolism . In spite of an unavoidable bias in
sex ratio in the data (621 females to 99 males),
in agreement with literature on deer antler,
there were significantly higher values for wool
element concentration in male animals for both
copper (?2 42.98 plt0.001 df1.) and lead (?2
3.86 plt0.05 df 1). Anabolic influence of
androgens has been implicated in enhanced metal
uptake in deer. Further studies are planned to
include consider a balanced and expanded survey
design in collaboration with the Wool Board, the
effect of age, wool sample site on matrix
adsorbed elementconcentration, the potential use
of wool as a bio-indicator in bio-remediation
studies in brownfield locations.
Acknowledgements The Rare Breeds Survival Trust
British Geological Survey, Nottingham.