Ahmedabad: They settle on the balcony railings of apartment complexes in Prahladnagar and perch on the water tanks of residential towers in Bodakdev. Ahmedabad’s blue rock pigeons are so familiar as to be invisible — a morning nuisance to be shooed away.But a new scientific study asks us to look more carefully. These birds, it turns out, have been quietly absorbing the toxic emissions from vehicles and factories into their tissues. Researchers Kanthan Nambirajan and Subramanian Muralidharan have found that naphthalene, phenanthrene, and fluoranthene are accumulating in the tissues of city birds, signalling a persistent environmental threat.
According to the study, conducted at the Salim Ali Centre for Ornithology and Natural History, “Polycyclic aromatic hydrocarbons (PAHs) are recognized as environmental threats because of their carcinogenic and mutagenic nature, widespread distribution, and potential for bioaccumulation”. By testing 37 birds across six species, the researchers found that “naphthalene (100%), phenanthrene (93%), and fluoranthene (46%) were the most frequently detected PAHs.” The paper states that the pigeon, “given its abundance in urban environments, close association with human activity, and ease of sampling, may serve as a practical bioindicator for PAH contamination.” The report cautions that “further studies are required to confirm source attribution” as current analytical ratios were originally developed for non-living environments like soil or water. While the levels detected are not immediately fatal, they indicate a “slow-motion” environmental crisis. The authors note, “While the concentrations observed were below known toxicity thresholds, their consistent presence in multiple species suggests chronic exposure.” The study will be published in Elsevier’s upcoming March 2026 journal called Science of The Total Environment.
