Abstract:
In this study, wild hatched eggshells were collected from the nests of the threatened Wattled
Crane and South Ground-Hornbill in an attempt to determine total Hg concentrations. A total
of fourteen eggshell samples from both bird species were collected from different study
areas in the Mpumlanga and KwaZulu-Natal Provinces, South Africa. The eggshells were
acid digested under reflux and their total Hg contents were determined using cold-vapour
atomic absorption spectrophotometry (CV-AAS). The observed total Hg levels for the South
Ground-Hornbill samples ranged from 1.31 to 8.88 μg/g dry weight (dw), except for one outlier which had an elevated 75.0 μg/g dw. The levels obtained for the Wattled Crane
samples were relatively higher and these ranged from 14.84 to 36.37 μg/g dw. Generally, all
the measured total Hg concentrations for the Wattled Crane samples exceeded the
estimated total Hg levels derived for eggshell which were known to cause adverse
reproductive effects in avian species from previous studies. Based on these findings, it is,
therefore, possible that the exposure of these birds to elevated Hg may have contributed to
their present population decline.
