Evaluation of Black-Headed Oriole Oriolus brachyrhynchus (Swainson, 1837) as Bioindicator of Arsenic Contamination Using Atomic Absorption Spectrometry (AAS)

Abstract

An evaluation of Black-headed oriole Oriolus brachyrhynchus as bioindicator of arsenic contamination using Atomic Absorption Spectrometry (AAS) was carried out to determine the bioaccumulation level of arsenic concentration in the liver, skin, heart, adult feathers, nestling feathers, and eggs so as to ascertain which of these parts harbours more contaminants. A total of 30 birds were trapped from different farm locations in Buruku, Daudu and Adega using mist net and 150 of parts were obtained. A total of 9 eggs and 9 nestling were also collected from different nest from the study locations for investigation. We also examined the crops foraged on, and the water and soil of the environment. Summary statistics of Arsenic concentration (mg/kg) in selected parts were expressed using descriptive statistics and correlation. Arsenic concentration in feathers of the said species ranged between 1.29- 2.49 mg/kg with Daudu having the highest mean of 1.84 ± 0.42 mg/kg, whereas Buruku and Adega have below detection limit of 0.001 µg/L. Arsenic concentration in the liver of Black headed oriole ranged between 0.28 – 1.57 mg/kg with the birds in Daudu having the highest mean of 0.70 ± 0.47 mg/kg. Arsenic concentration in the skin ranged between 0.19 – 0.79 mg/kg with the birds in Daudu having the highest mean of 0.46 ± 0.21 mg/kg. Consequently arsenic concentration in carcass of Black headed oriole ranged between 0.28 – 3.42 mg/kg with the birds in Daudu having the highest mean of 2.47 ± 0.94 mg/kg. In addition, arsenic concentration in eggs and nestling feathers ranged between 0.04 – 0.05 mg/kg and 1.29 – 2.22 mg/kg with Daudu having highest arsenic concentration in both parts with mean of 0.05± 0.01 mg/kg and 1.63 ± 0.51 mg/kg respectively. Arsenic content of maize obtained from Daudu ranged between 0.46 - 0. 66 mg/kg with Daudu having the highest arsenic content with mean of 0.53 ± 0.11 mg/kg. In addition, arsenic content of soil ranged between 2.95 – 23.98 mg/kg with mean of 23.83 ± 0.14 mg/kg. Arsenic content of water ranged between 0.02 – 0.06 mg/kg. Therefore Daudu has the highest arsenic content in soil and water as a component of biological pathway for both crop plants and birds. The concentration of arsenic in different parts of the birds is a function of different time of exposure of individual bird trapped from different location, while arsenic levels in the feathers is an indicator of diet. It is imperative to study the potential mechanism by which arsenic cause diseases in wild birds which may be applicable to bird’s conservation to promote the conservation of wild birds and other animals especially species that are endanger and threaten. Therefore, analysis of mercury, lead, chromium and cadmium should be carried out to determine their accumulation in organs of Black headed oriole since these communities are agrarian communities.