Contents lists available at ScienceDirect Ecotoxicology and Environmental Safety journal homepage: www.elsevier.com/locate/ecoenv Does gender influence the levels of heavy metals in liver of wild boar? C. Neila a , D. Hernández-Moreno b,c , L.E. Fidalgo d , A. López-Beceiro d , F. Soler a,e , M. Pérez- López a,f, ⁎ a Toxicology Area, Faculty of Veterinary Medicine (UEX), 10003 Caceres, Spain b National Institute for Agricultural and Food Research and Technology (INIA), 28040 Madrid, Spain c Universidad Autónoma de Chile, Chile d Department of Veterinary Clinical Sciences, Faculty of Veterinary Medicine (USC), 27003 Lugo, Spain e IPROCAR Research Institutes f INBIO G+C Research Institutes ARTICLE INFO Keywords: Wild boar Liver Metal Gender ABSTRACT The aim of this study was to determine heavy metal reference levels for risk assessment studies. For this purpose, the levels of lead, cadmium, copper and zinc were determined in liver tissues of wild boars sampled in NW Spain. The mean values were 0.383, 0.326, 23.50 and 56.86 mg/kg dried weight, respectively. In general, the levels detected were similar to or lower than the levels reported in literature. This study not only provides a useful baseline for biomonitoring the levels of the analyzed contaminants in wildlife in NW Spain, it also helps to understand the effects of gender on the levels of these elements. Similar to studies performed in other geographical regions, no significant gender-related differences could be detected. Although differences were not significant, the levels of zinc, cadmium and lead were modestly higher in males (55.78, 0.346 and 0.424 mg/kg, respectively) compared to females (45.25, 0.305 and 0.341 mg/kg). Our results indicate that, although gender did not significantly affect heavy metal uptake and toxicokinetics of contaminants in wild boars, these effects could vary between species, populations, organs, and elements. It is therefore essential to investigate gender- related differences for each species. 1. Introduction Heavy metals, including lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) are natural components of the Earth's crust. However, past and present industrial activities have resulted in a constant increase in their environmental concentrations, thereby potentially affecting wild- life adversely. Pb and Cd have no biological functions, are highly toxic, may induce both acute and chronic toxicological effects and have important ecotoxicological effects on wildlife and human health. Although Zn and Cu are essential for health and growth of animals, both reduced and excessive levels may have serious consequences on the ecosystem (Pérez-López et al., 2016). Due to their persistence and biomagnification through the food chain and potential toxicity, ex- posure to these chemical pollutants is of particular concern. The transfer of pollutants from the environment to biota is influenced by different environmental and biological parameters (Baker et al., 2003). Recently, the influence of gender on bioavailability, transfer and effects of contaminants has been demonstrated (Baker et al., 2003; Gonzalez et al., 2008; Fritsch et al., 2010; Tchounwou et al., 2012). Uptake, biokinetics and response to pollutants may differ significantly between male and female organisms due to differences in gene expression, germ cells, physiology and behavior (Burger, 2007). In addition, the repro- ductive status and period of the year may also affect gender-related patterns for metal accumulation (Robillard et al., 2002; Burger et al., 2007). Studying wildlife populations in environments that could be poten- tially changed or damaged through anthropogenic activities provides relevant information about the viability and balance of those ecosys- tems. In addition, the use of natural populations as sentinels for environmental contamination helps to expand our knowledge of and to improve the response to environmental and human health concerns (Alleva et al., 2006). Species used for monitoring purposes should cover various levels of the food chain, such as primary (herbivorous) and secondary (carnivorous) consumers (Sánchez-Chardi et al., 2009). Game species can be used in biomonitoring studies (Froslie et al., 2001) since their tissues are known to be good bioindicators for toxic metal pollution (Santiago et al., 1998; Millan et al., 2008; Pérez-López et al., 2016). Wild boars (Sus scrofa) are considered particularly suitable http://dx.doi.org/10.1016/j.ecoenv.2017.02.025 Received 23 December 2016; Received in revised form 15 February 2017; Accepted 16 February 2017 ⁎ Corresponding author. E-mail address: marcospl@unex.es (M. Pérez-López). Ecotoxicology and Environmental Safety 140 (2017) 24–29 0147-6513/ © 2017 Elsevier Inc. All rights reserved. MARK