Faecal Matter of Spotted Deer (Axis axis) Acts as Bioindicator of Heavy Metals Contamination in the Air

Heavy metals are high density compounds found in the earth crust and atmosphere. These metals in small amounts are important for normal metabolism of body but become very toxic when present in large amounts due to their capabilities of bio-accumulation in organisms. To see exposure of these metals in the environment, different invasive and non-invasive techniques are used. In the present study, enclosure of Axis axis commonly known as spotted dear was selected from Lahore and Bahawalpur zoo. Non-invasive technique was used to monitor heavy metal exposure and both biological (faecal, feed) and non-biological (water, soil) samples were collected. Soil was collected from different depths (6, 12, 18 inches) to study deposition patterns of metals. Samples were chemically digested and finally analysed by Flame Atomic Absorption Spectrometery (FAAS) for four heavy metals such as Pb, Cd, Zn and Cu. The results showed all the metals were in safe range in feed samples, a very negligible amount was present in water samples and small concentrations were noticed in soil samples. The amounts of Zn and Cu in feed were reflected in fecal samples; however, higher amount of Pb and Cd were noticed in fecal samples compared to feed, water and soil. This showed inhalation of these metals from the air. Amount of metals at different depths showed unique pattern low to high and again low that was irrespective of site location. Overall there was more exposure to air pollutants noticed for Lahore zoo compared to Bahawalpur zoo.