The Oriental white-backed vulture (OWBV; Gyps bengalensis) was once one of the most common raptors in the Indian subcontinent. A population decline of >95%, starting in the 1990s, was first noted at Keoladeo National Park, India. Since then, catastrophic declines, also involving Gyps indicus and Gyps tenuirostris, have continued to be reported across the subcontinent. Consequently these vultures are now listed as critically endangered by BirdLife International. In 2000, the Peregrine Fund initiated its Asian Vulture Crisis Project with the Ornithological Society of Pakistan, establishing study sites at 16 OWBV colonies in the Kasur, Khanewal and Muzaffargarh-Layyah Districts of Pakistan to measure mortality at over 2,400 active nest sites. Between 2000 and 2003, high annual adult and subadult mortality (5-86%) and resulting population declines (34-95%) (ref. 5 and M.G., manuscript in preparation) were associated with renal failure and visceral gout. Here, we provide results that directly correlate residues of the anti-inflammatory drug diclofenac with renal failure. Diclofenac residues and renal disease were reproduced experimentally in OWBVs by direct oral exposure and through feeding vultures diclofenac-treated livestock. We propose that residues of veterinary diclofenac are responsible for the OWBV decline.

The population declines affecting Asian Gyps vultures are among the most rapid and geographically widespread recorded for any species. This paper describes the rates and patterns of mortality and population change over 4 years at three Oriental white-backed vulture Gyps bengalensis colonies in Pakistan: Dholewala (initially 421 pairs), Toawala (initially 445 pairs) and Changa Manga (initially 758 pairs). Vulture mortality led to the extirpation of two of these colonies (Changa Manga and Dholewala) in 3 years, and a decline of 54.3% in the third. Visceral gout, indicative of diclofenac poisoning, was the largest single cause of death in vultures examined. Annual adult mortality from diclofenac poisoning was significantly positively correlated with annual population declines at each colony indicating a direct causal relationship. Visceral gout occurred in temporal and spatial clusters suggesting multiple point sources of diclofenac exposure. The spatial and temporal distribution of dead vultures and approximate time since death were used to estimate minimum rates at which colonies encountered carcasses with sufficient diclofenac to cause mortality of 1.26–1.88 carcasses per colony per month. By estimating total carcass consumption at each colony, the percentage of carcasses contaminated with diclofenac was calculated as 1.41–3.02%, exceeding the minimum required to have caused the observed population decline. With populations declining by approximately 50% annually, the long term survival of Gyps vultures in South Asia will require the removal of diclofenac from vulture food and establishment of captive populations for future restoration once the environment is free from contamination.

Informal e-waste recycling activities have been shown to be a major emitter of organic flame retardants (FRs), contributing to both environmental and human exposure to laborers at e-waste recycling sites in some West African countries, as well as in China and India. The main objective of this study was to determine the levels of selected organic FRs in both air and soil samples collected from areas with intensive informal e-waste recycling activities in Karachi, Pakistan. Dechlorane Plus (DP) and "novel" brominated flame retardants (NBFRs) were often detected in high concentrations in soils, while phosphorus-based FRs (OPFRs) dominated atmospheric samples. Among individual substances and substance groups, decabromodiphenyl ether (BDE-209) (726 ng/g), decabromodiphenyl ethane (DBDPE) (551 ng/g), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE) (362 ng/g), and triphenyl-phosphate (∑TPP) (296 ng/g) were found to be prevalent in soils, while OPFR congeners (5903-24986 ng/m) were prevalent in air. The two major e-waste recycling areas (Shershah and Lyari) were highly contaminated with FRs, suggesting informal e-waste recycling activities as a major emission source of FRs in the environment in Karachi City. However, the hazards associated with exposure to PM appear to exceed those attributed to exposure to selected FRs via inhalation and soil ingestion.

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