Heavy metals in eggshells of cattle egret (Bubulcus ibis) and little egret (Egretta garzetta) from the Punjab province, Pakistan.

Concentrations of nine trace metals were determined to assess site-specific and species-specific differences using Fast Sequential Atomic Absorption Spectrophotometer (Varian FAAS-240) in eggshells of Bubulcus ibis and Egretta garzetta from seven heronries in the Punjab province, Pakistan. Pattern of metal concentration followed the order: Fe > Zn > Pb > Mn > Cd > Cr > Li > Cu > Ni. Greater mean concentrations of Mn(1.17 μg/g), Ni(0.11 μg/g), Pb(1.49 μg/g), Cd(0.88 μg/g), Cr(0.7 μg/g), Cu(0.20 μg/g) and Li(0.27 μg/g) were recorded in little egret. Mean concentrations of Mn, Pb, and Cr, (3.98, 5.4, 0.8 μg/g) were significantly higher in eggshells collected from Shorkot; Cu, Zn and Ni (0.19, 13.0, 0.12 μg/g) from the Trimu Headwork; Cd (1.23 μg/g) from Jhang Faisalabad Road and Fe (67.98 μg/g) from Mailsi. Multivariate analyses indicated that Mn, Pb, Cd, Ni, Cu, Cr and Zn were associated with anthropogenic activities and Fe and Li with natural origin. This study provides the baseline data for a monitoring program and revealed that egg-shells can serve as a bio-monitor of local metal contamination.