Assessment of environmental contamination using feathers of Bubulcus ibis L., as a biomonitor of heavy metal pollution, Pakistan Riffat Naseem Malik Æ Naila Zeb Accepted: 6 April 2009 / Published online: 6 May 2009 Ó Springer Science+Business Media, LLC 2009 Abstract Concentrations of metals such as Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, Pb, and Zn were analyzed in the feathers of cattle egret (Bubulcus ibis) from three breeding colonies in the Punjab province, Pakistan. The mean concentrations of Ca, Cd, Fe, Pb and Mn were sig- nificantly different between the three study sites (River Chenab, River Ravi and Rawal Lake Reservoir). The mean concentrations of Ca, Cd, Fe and Mn were significantly greater at the River Chenab heronry and Cr, Co, Zn, and Pb concentrations at the River Ravi heronry. The feathers of cattle egrets collected from the Rawal Lake Reservoir heronry were least contaminated. Multivariate statistical methods viz., Factor Analysis based on Principal Compo- nent Analysis (FA/PCA); Hierarchical Cluster analyses (HACA), and Correlation Analyses identified relatively similar associations of metals and their sources of input. Metals such as Ca, Mg, and K were related with natural input from parent rock material whereas trace metals viz., Cu, Cd, Co, Pb, Ni, and Zn were associated mainly with anthropogenic processes. Metals such as Fe, Mn, and Li were either correlated with natural input or with anthro- pogenic activities. Concentration of heavy metals such as Cd, Pb, and Cr were well above the threshold level that can cause adverse effects in birds and pose menace to the cattle egrets population in Pakistan. The study suggested that the feathers of cattle egret could be used as a bio-monitor of the local heavy metals contamination. Keywords Heavy metals Á Multivariate analysis Á Biomonitoring Á Cattle egrets Á Feathers Á Pakistan Introduction Heavy metals contamination is a great concern at global, regional and local level (Qadir et al. 2008) and influence the functional and structural integrity of an ecosystem (Qadir and Malik 2009). Heavy metals are ubiquitous, highly persistent, and non-biodegradable with long bio- logical half-lives (Burger et al. 2007). Toxic concentrations of heavy metals affect the central nervous system and disrupt the functioning of internal organs (Lee et al. 2006). Among heavy metals, organic forms of mercury and arsenic do biomagnify in the food chain (Hoffman and Curnow 1979; De Luca-Abbott et al. 2001; Kojadinovic et al. 2007; Zolfaghari et al. 2007) and pose threats to the species at high trophic position with more bioaccumulation capacities. Heavy metals have been identified worldwide in diverse environmental compartments. Many studies have been car- ried out to investigate the level of their occurrence, accu- mulation and distribution (Burger and Gochfeld 1993, 2000c; Goutner et al. 2001; Kojadinovic et al. 2007; Kim and Koo 2007a; Qadir et al. 2008). These contaminants are added continuously to the pool of contaminants in the environment from anthropogenic as well as natural processes. Biological organisms and populations at different tro- phic levels are widely used as a biological indicator and/or bio-monitor to provide evidence of contaminant exposure and effects of one or more chemical pollutants (Covaci et al. 2002; Mateo and Guitart 2003; Dauwe et al. 2003, 2004; Martin-Diaz et al. 2005; Dural et al. 2006; Eeva et al. 2006; Kojadinovic et al. 2007). ‘‘Different species of birds such as herons and egrets have been used as a bio-indicator and/or bio-monitor of local environmental contamination because they are high on the food-chain, exposed to a wide range of chemicals, susceptible to bioaccumulation and are R. N. Malik (&) Á N. Zeb Environmental Biology Laboratory, Department of Plant Sciences, Quaid-i-Azam University, Islamabad 4600, Pakistan e-mail: r_n_malik2000@yahoo.co.uk 123 Ecotoxicology (2009) 18:522–536 DOI 10.1007/s10646-009-0310-9