Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Baseline Mercury, arsenic, cadmium and lead in two commercial shark species (Sphyrna lewini and Caraharinus porosus) in Trinidad and Tobago Azad Mohammed a,⁎ , Terry Mohammed b a Department of Life Sciences, Faculty of Science and Technology, The University of the West Indies, Trinidad and Tobago b Department of Chemistry. Faculty of Science and Technology, The University of the West Indies, Trinidad and Tobago ARTICLE INFO Keywords: Trinidad and Tobago Mercury Arsenic Shark Lead Cadmium ABSTRACT Sharks are long-lived apex predators which can accumulate toxic metals such as mercury and arsenic. Samples of Sphyrna lewini and Carcharinus porosus were collected from two commercial fish landing sites in Trinidad. Heavy metal concentrations were determined in the muscle, dorsal fin, vertebrae and liver using atomic absorption spectrometric. The provisional tolerable weekly intake (PTWI) and target hazard quotient (THQ) were determined to assess the potential health risks to consumers. Mercury levels ranged between 74–1899 μg/kg in S. lewini and 67–3268 μg/kg in C. porosus. Arsenic levels ranged between 144–2309 μg/kg in S. lewini and 762–6155 μg/kg in C. porosus. Cadmium levels generally ranged between 0.27–27.29 mg/kg in S. lewini and 0.6–29.89 mg/kg in C. porosus. Lead levels generally ranged between 0.14 and 208.81 mg/kg in S. lewini while C. porosus levels ranged between 0.30 and 459.94 mg/kg. The PTWI and THQ values suggest that consumption of these shark species can therefore be a major source of exposure to lead, cadmium, arsenic and mercury in humans and is likely to have potential health risk over long term exposure. Heavy metals are of global concern because of their high toxicity, potential to accumulate through food webs and the significant health risk they pose upon ingestion. Sharks, which are long-lived, apex predators, occupy the highest trophic levels in the marine environment and can efficiently bioaccumulate heavy metals to levels which may exceed the safe limits for human consumption. For example, in 1991, the Florida Department of Health and Rehabilitative Services issued fish advisories recommending limited consumption of sharks after investi- gations found that they contained high levels of Hg (3.9 mg/kg) (Florida Department of Health and Rehabilitative Services, 1991). Furthermore, the Florida Department of Health (FDOH) currently advises that women of childbearing age and young children should not consume shark while others should not eat large sharks (> 109 cm) and limit consumption of smaller sharks to one meal per month (FDOH, 2013). Mercury, cadmium and lead levels in shark tissues have been previously reported (Glover, 1979; Cornish et al., 2007; Bosch et al., 2016; Hueter et al., 1995; Storelli et al., 2003; Garcia-Hernandez et al., 2007; Evers et al., 2008) in various studies. However, fewer studies have focused on arsenic contamination in sharks and other marine species (Hanaoka et al., 1986; USEPA, 1997; Storelli et al., 2005; Falcoä et al., 2006; Gutiérrez-Mejía et al., 2009). Arsenic levels in marine organisms can vary widely, but typical levels range between 1 and 100 μg As g -1 . However, despite high levels of total arsenic in seafood, ingestion of seafood is not easily linked to arsenic toxicity in humans (Edmonds and Francesconi, 1993). Consumption of low levels of arsenic can increase the risk of cancer; therefore it is still worthwhile to consider the potential long term cancer risk since ingestion of seafood may lead to the generation of metabolites involved in arsenic-induced carcinogenesis. Other metals such as cadmium and lead have no biological importance in organisms and can also have toxicological effects on kidneys, bone and nervous systems. Seafood consumption has changed significantly over the past four decades. Global fish consumption has increased from 9.6 kg per capita in the 1960′s to 15 kg per capita in 2011. In 2016, global consumption exceeded 20 kg per capita, an increase that was attributed to increased supplies from aquaculture and improved fisheries management. Fish consumption rates in Caribbean countries typically range between 10 and 60 kg per capita, with many of the islands (Anguilla = 49.5 kg; Antigua and Barbuda = 55.2 kg; Barbados = 40.6 kg; Grenada = 44 kg; St Lucia = 32.5 kg) having consumption rates above the 2011 global average (15 kg per capita) (FAO, 2013). The most common fish species consumed in the region include; Scomberomorus brasiliensis, Scomberomorus cavalla, Lutjanus purpureus and Micropogonias furnieri. Sharks are not readily consumed except in a few countries such a Trinidad and Tobago where consumption rates are typically high. Trinidad and Tobago captures about 488 tonnes of shark http://dx.doi.org/10.1016/j.marpolbul.2017.04.025 Received 26 August 2016; Received in revised form 10 April 2017; Accepted 13 April 2017 ⁎ Corresponding author. E-mail address: azad.mohammed@sta.uwi.edu (A. Mohammed). Marine Pollution Bulletin xxx (xxxx) xxx–xxx 0025-326X/ © 2017 Elsevier Ltd. All rights reserved. Please cite this article as: Mohammed, A., Marine Pollution Bulletin (2017), http://dx.doi.org/10.1016/j.marpolbul.2017.04.025