Bioaccessibility, dietary exposure and human risk assessment of heavy metals from market vegetables in Hong Kong revealed with an in vitro gastrointestinal model Junli Hu a,b,c , Fuyong Wu a,c,d , Shengchun Wu a,c , Zhihong Cao b,c , Xiangui Lin b,c,⇑ , Ming Hung Wong a,c,⇑ a Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, PR China b State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, East Beijing Road 71, Nanjing 210008, PR China c Joint Open Laboratory of Soil and the Environment, Hong Kong Baptist University & Institute of Soil Science, Chinese Academy of Sciences, PR China d Department of Environmental and Municipal Engineering, Henan University of Urban Construction, Mingyue Road, Pingdingshan 467036, PR China highlights " 26%, 16%, and 0.56% of vegetables in Hong Kong were contaminated by Cd, Pb, and Cr. " The average bioaccessibilities of Cd, Cr, Cu, Ni, Pb, and Zn varied within 20–96%. " The total BTHQ of the six HMs were 0.18 and 0.64 for average and high consumers. " The Cd and leafy vegetable were the major risk contributors for local inhabitants. " Human risk assessment should be modified by taking bioaccessibility into account. article info Article history: Received 30 July 2012 Received in revised form 15 October 2012 Accepted 27 November 2012 Available online 27 December 2012 Keywords: Cadmium (Cd) Contamination Estimated daily intake (EDI) High consumer Leafy vegetable Target hazard quotient (THQ) abstract A systematic survey of heavy metal (HM) concentrations and bioaccessibilities in market vegetables in Hong Kong were carried out for assessing potential health risk to local inhabitants. The average concen- trations of Cd, Pb, Cr, Ni, Cu, and Zn in nine major groups of fresh vegetable varied within 0.007–0.053, 0.05–0.17, 0.05–0.24, 0.26–1.1, 0.62–3.0, and 0.96–4.3 mg kg 1 , respectively, and their average bioacces- sibilities varied within 21–96%, 20–68%, 24–62%, 29–64%, 30–77%, and 69–94%, respectively. The bioac- cessible estimated daily intakes (BEDIs) of Cd, Pb, Cr, Ni, Cu, and Zn from vegetables were far below the tolerable limits. The total bioaccessible target hazard quotient (TBTHQ) of the six HMs was 0.18 and 0.64 for average and high consumers, respectively, with Cd and leafy vegetable being the major risk contrib- utors. Risk assessment of HMs from foods should be modified by taking bioaccessibility into account. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Vegetables constitute an important part of the human diet since they contain carbohydrates, proteins, vitamins, minerals and fibers required for human health (Suruchi and Khanna, 2011). They are also able to accumulate heavy metals (HMs) such as Cd, Cu, Cr, Ni, Pb, and Zn in their edible and non-edible parts (Singh et al., 2010). Although some of the HMs such as Zn, Ni and Cu act as mi- cro-nutrients to maintain normal body function at lower concen- trations, the excessive intake of these essential elements may also affect human health (Powers et al., 2003). On the other hand, the nonessential HMs such as Cd, Cr, and Pb are known to cause deleterious effects on human health (Jarup, 2003). As human activ- ity increases, especially the application of modern technologies, contamination of human food chain has become inevitable (Suruchi and Khanna, 2011). It is believed that vegetables can be- come contaminated with HMs if they grow on soils contaminated by mining, vehicular exhaust, industrial activities and other agri- cultural activities (Li et al., 2006). Although the concentrations of HMs in soils and vegetables have been well studied, the attention 0045-6535/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.chemosphere.2012.11.066 ⇑ Corresponding authors. Addresses: Croucher Institute for Environmental Sci- ences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, PR China. Tel.: +852 34117746; fax: +852 34117743 (M.H. Wong), State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, PR China. Tel.: +86 25 86881589; fax: +86 25 86881000 (X. Lin). E-mail addresses: jlhu@issas.ac.cn (J. Hu), xglin@issas.ac.cn (X. Lin), mhwong@hkbu.edu.hk (M.H. Wong). Chemosphere 91 (2013) 455–461 Contents lists available at SciVerse ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere