Arsenic and mercury in bird feathers: Identification and quantification of inorganic pesticide residues in natural history collections using multiple analytical and imaging techniques Stanislav Strekopytov a, ⁎, Will Brownscombe a , Chaipat Lapinee b , Dan Sykes a,1 , John Spratt a , Teresa E. Jeffries a,2 , Chris G. Jones a a Core Research Laboratories, Natural History Museum, Cromwell Road, London SW7 5BD, UK b Department of Chemistry, Imperial College London, London SW7 2AZ, UK abstract article info Article history: Received 24 September 2016 Received in revised form 9 October 2016 Accepted 9 October 2016 Available online xxxx Life science collections and their curated metadata are now seen as potential archives of environmental levels of trace elements. Bird feathers are especially promising material, but surface contamination might present a signif- icant issue. The suitability of preserved specimens for environmental studies may be further limited by historical application of inorganic pesticides in the collections. Arsenic (As) and mercury (Hg) are the most significant in- organic contaminants in natural history collections since they were widely applied as pesticides from the late 18th century until the 1980s. Potential presence of As- and Hg-containing pesticide residues has also to be taken into account when members of the public are allowed to handle specimens. Even though the testing of taxi- dermy and anthropology museum collections for pesticide residues is becoming a common practice, it is gener- ally done qualitatively rather than quantitatively. In this study, the concentrations of As and Hg were determined in feathers of eleven bird specimens considered for an interactive display and were found to range from 1.1 to 15,183 μgg -1 and from b 1 to 26,960 μgg -1 , respectively. The study shows how the quantitative information can be obtained and the history of the pesticide treatment reconstructed using a combination of analytical tech- niques including bulk analysis by inductively coupled plasma mass spectrometry (ICP-MS) following destructive or non-destructive sampling, and spatially resolved techniques such as laser ablation (LA)-ICP-MS and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). Inorganic As speciation by squarewave anodic stripping voltammetry (SWASV) and localisation of pesticide residues by X-ray micro-computed tomog- raphy (μCT) can provide additional information. It is found that As is not only present as micron-sized particulate residues, but becomes incorporated into the keratin matrix of the feathers. Mercury is probably nano-particulate and fully incorporated into keratin. The history of pesticide treatment might be complicated with mixtures of chemicals involving both As and Hg compounds and more than one way of pesticide application used on the same specimen. © 2016 Elsevier B.V. All rights reserved. Keywords: life science collections inductively coupled plasma mass spectrometry laser ablation ICP-MS X-ray microtomography arsenic mercury 1. Introduction Life science collections and their curated metadata are now seen as potential archives of environmental levels of trace elements [1–3]. Trace metal concentrations in bird tissues and feathers are studied in context of their relationship with the environmental contamination (e.g. [4]). An active discussion is taking place on how to exclude surface contamination in determining metal contents of bird feathers [5]. Changes in metal concentrations (e.g., in feathers) induced by conserva- tion treatment have also been discussed [6]. The suitability of preserved specimens for environmental studies may be further limited by histori- cal application of inorganic pesticides in the collections [3,7]. Arsenic (III) oxide (As 2 O 3 ) historically known as ‘white arsenic’ and mercury (II) chloride (HgCl 2 ) known as ‘corrosive sublimate’ were first used for the preservation of natural history specimens probably in the 17th cen- tury [8] and widely applied since the 1770s. Natural history collections that include specimens prepared before the 1980s are likely to contain historical pesticide residues [9]. In the 1970s, As compounds were still recommended for skin treatment of taxidermy specimens [10]. The National Park Service (USA) used As compounds until at least 1976 and mercuric chloride until at least 1980 [11]. Elevated concentrations of As in dust were found in Microchemical Journal 130 (2017) 301–309 ⁎ Corresponding author. E-mail addresses: s.strekopytov@nhm.ac.uk (S. Strekopytov), w.brownscombe@nhm.ac.uk (W. Brownscombe), chaipat.lapinee12@imperial.ac.uk (C. Lapinee), dan.sykes@postgrad.manchester.ac.uk (D. Sykes), j.spratt@nhm.ac.uk (J. Spratt), c.jones@nhm.ac.uk (C.G. Jones). 1 Current address: School of Materials, University of Manchester, Oxford Road, Manchester, M13 9PL, UK. 2 Deceased. http://dx.doi.org/10.1016/j.microc.2016.10.009 0026-265X/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Microchemical Journal journal homepage: www.elsevier.com/locate/microc