Uptake and depuration of PCB-153 in edible shrimp Palaemonetes varians and human health risk assessment T.F. Grilo a,n , P.G. Cardoso b , P. Pato c , A.C. Duarte c , M.A. Pardal a a CFE—Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, PO-BOX 3046, 3001-401 Coimbra, Portugal b IMAR – CMA – Marine and Environmental Research Centre, Department of Life Sciences, University of Coimbra, 3004-517 Coimbra, Portugal c Department of Chemistry & Center for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193 Aveiro, Portugal article info Article history: Received 21 August 2013 Received in revised form 18 December 2013 Accepted 20 December 2013 Keywords: Palaemonetes varians PCB-153 Bioaccumulation Depuration Food safety Human health abstract A medium-term mesocosm exposure study was conducted to elucidate bioaccumulation and depuration of polychlorinated biphenyl congener 153 (PCB-153) in edible shrimp Palaemonetes varians. Over the 15-day exposure period, shrimp under different exposure concentrations exhibited a significant increase in PCB-153 concentration compared with control organisms. Distinct bioaccumulation patterns and uptake rates were observed depending on the exposure concentrations. For low PCB-153 exposure levels (0.25 μgL À1 ), accumulation followed a saturation model, reaching an apparent steady state after fifteen days exposure. For intermediate (2.5 μgL À1 ) and high PCB-153 levels (25 μgL À1 ), accumulation was faster and linear. In addition, the bioaccumulation rate was not proportional to PCB-153 concentration, and the bioaccumulation was higher at intermediate exposure concentrations. Regarding the depuration phase, P. varians lost up to 30% of PCB-153 after 72 h and levels continued slowly to decrease until the end of the 30-d experimental period. However, PCB-153 levels in shrimp did not reach background values, and those exposed to moderate and high PCB-153 concentrations presented contamination levels much higher than the regulatory limit for human food consumption (75 ng g À1 ww for Σ 6 PCB). & 2013 Elsevier Inc. All rights reserved. 1. Introduction Among persistent organic pollutants (POPs), polychlorinated biphenyls (PCBs) are recognized as one of the largest groups of widespread anthropogenic contaminants, comprising a total of 209 congeners with different physicochemical and toxicological properties. By the 1970s, owing to serious concerns pertaining to their human toxicity, suspected carcinogenicity and environmental persistence, several countries limited the use and production of PCBs, but it was only in 1985 that their use and marketing in the European Community was heavily restricted. Since PCBs are highly lipophilic, they can bioaccumulate in the adipose tissues of exposed organisms. They are present in various compartments, both biotic (from plankton to humans) (Wang et al., 1998; Voorspoels et al., 2004; Helm et al., 2008; Croes et al., 2012) and abiotic (air, water, sediments, soil) (Howell et al., 2008; Han et al., 2010; Cachada et al., 2012). Furthermore, biomagnification through the food chain has been well documented, posing serious risks for both wildlife and humans (Borga et al., 2001; Skarphedinsdottir et al., 2010; Nunes et al., 2011). Since the main pathway of human exposure to PCBs is through dietary intake, namely by ingestion of edible marine species (Nunes et al., 2011; Fillos et al., 2012), the public and the food regulatory agencies are particularly concerned about the potential health effects associated with their consumption (Bodin et al., 2007). Crustaceans are a diverse group of marine organisms with enormous importance in the food webs, tending to accu- mulate large amounts of lipophilic contaminants in their tissues (Voorspoels et al., 2004; Bodin et al., 2007). Within crustaceans, shrimp have singular interest since they are an important prey for both ichthyo and avifauna and represent a highly consumed food item worldwide. The Food and Agriculture Organization estimated a global annual production of 3.4 million tons of cultivated marine shrimp commonly fed on fresh food items, farm-made and/or commercially compounded aquafeeds, valued at more than US$ 14 million (FAO, 2011). The ditch shrimp Palaemonetes varians (Leach 1814) is a small decapod caridean species, commonly found in salt ponds and estuaries worldwide, demonstrating high tolerance to a broad range of temperatures and salinities (Oliphant et al., 2011). It is a species of great economic importance, used as bait for fishery species and for human consumption. In Portugal, its production in intensive systems reaches 200–300 kg ha À1 yr À1 with an average price of nearly 10 eur kg À1 . Since coastal areas are subjected to great human pressure and are frequently under episodic contaminant events, it is crucial to Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety 0147-6513/$ - see front matter & 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ecoenv.2013.12.020 n Corresponding author. Fax: þ351 239 855211. E-mail address: tgrilo@uc.pt (T.F. Grilo). Ecotoxicology and Environmental Safety 101 (2014) 97–102