Abstract:
South Africa is one of the most diverse countries in the world but the increase in
agricultural, industrial and technological development to meet the needs of the growing
human population has led to increased amounts of potentially toxic elements (PTEs) and
other chemicals in the environment. As regional and global environmental processes
influence local conditions to differing degrees, all organisms within a specific environment
are exposed to highly complex, ill-defined PTE and chemical mixtures. Differences in
feeding strategies within and between vertebrate trophic levels are likely to influence the
degree to which individuals may be exposed to and affected by PTE presence. Using
vertebrate faeces as a biological matrix, we investigate and compare quantitative
differences in PTE concentrations in herbivorous, omnivorous and carnivorous
terrestrial vertebrates from two protected areas in South African savannah. Of the
eleven PTEs assessed [aluminium (Al), arsenic (As), barium (Ba), cadmium (Cd),
chromium (Cr), mercury (Hg), lead (Pb), antimony (Sb), tin (Sn), strontium (Sr), and
vanadium (V)], the highest concentrations of Al, As, Cr, Pb, Sn, and V were found in
carnivores. General patterns were evident between groups at each site for specific
elements, but absolute values for the same elements were site-specific. This is the first
study to non-invasively examine and compare PTE concentrations in a variety of freeranging mammalian wildlife occupying different trophic levels within South African
protected areas. Our results confirm that all individuals across trophic levels within
these sites are exposed to multiple and varied PTE mixtures on a continuous basis.
Whether PTEs at these concentrations cause synergistic or antagonistic disruption of
physiological and biological systems alone or in combination in free-ranging African wildlife
species is still unclear and requires further investigation.
