heavy metal contamination in Eastern Gray squirrel populations

[Diggie's Friend]

https://www.jstor.org/stable/44148805

JOURNAL ARTICLE
LEAD CONCENTRATIONS IN SUBURBAN AND RURAL GRAY SQUIRREL (SCIURUS CAROLINENSIS) POPULATIONS
CARL R. PRATT

Journal of the Pennsylvania Academy of Science
Vol. 62, No. 1 (September, 1988), pp. 3-5 (3 pages)
Published By: Penn State University Press

Abstract
Hair samples from twenty-one gray squirrels (Sciurus carolinensis) collected from two different sites were analyzed for lead concentration. Hair samples were taken from live-trapped squirrels and subjected to atomic absorption spectrophotometry to determine ppm lead. The collection sites were selected to provide two possible exposure regimes based upon vehicular traffic densities: a rural location on the Wilkes-Barre Campus of the Pennsylvania State University (low exposure site) and a suburban site in Kingston, Pennsylvania (high exposure site). Samples from the suburban site contained approximately 6.7 times the concentration of lead (x̄ = 1.22 ± 0.42 ppm) of those samples from the rural site (x̄ = 0.18 ± 0.07 ppm).

Results from other studies noted in this article, attributed the higher levels of lead contamination from automobile emissions.
As noted, lead is absorbed directly from contaminated food and water, and from inhaling lead emissions.

This would appear to raise a question whether to release squirrels rescued in urban areas where lead contamination is higher than into rural areas where it is significantly lower? Also, with less traffic in rural areas, there is moreover a lower mortality from traffic, than in higher traffic suburban areas.

I say moreover, as there has been the rare mass migration of E. Gray Squirrels which occurs from time to time rural areas; which most sadly has resulted in higher traffic mortalities.

[Diggie's Friend]

This is a reason not to supply soil for tree squirrels in long-term captive care in urban and suburban areas.

"Heavy metal concentrations in kidneys of urban gray squirrels"

https://pubmed.ncbi.nlm.nih.gov/16498879/