Polycyclic aromatic hydrocarbons evaluation in Portuguese shrimp samples

Introduction: Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental contaminants that primarily result from incomplete combustion or pyrolysis of organic materials1. These contaminants are endocrine disruptors, are lipophilic and have the capacity to accumulate in biota. PAHs can enter in the aquatic environment via numerous pathways, including petroleum contamination, surface runoff and industrial sewage discharge2. Shrimps are commonly distributed in coastal areas, feed on phytoplankton, are a food source for larger animals and can be a healthy addition to our diet3. Although this crustacean is a good complement to our diet, it can also be an exposure vehicle to environmental contaminants, namely PAHs. In this study, the concentrations of 18 PAHs (16 US EPA priority pollutants, benzo[j]fluoranthene recommended by European Directive, 2004/107/EC) and dibenzo [a,l] pyrene) were investigated, in shrimp (wild and aquiculture) from Portuguese coast. Experimental: The specie Palaemon serratus was collected by a local fisherman in four sampling sites along the Northwest Portuguese coast (Vila do Conde, Matosinhos, Aveiro and Figueira da Foz) and the specie Palaemon varians was collected in Sado estuary (wild and aquiculture samples) 2017-2019. PAHs analyzed: naphthalene (Naph), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Flu), phenanthrene (Phe), anthracene (Ant), fluoranthene (Fln), pyrene (Pyr), benz[a]anthracene (B[a]A), chrysene (Chry), benzo[b]fluoranthene (B[b]Ft), benzo[k]fluoranthene (B[k]Ft), benzo[a]pyrene (B[a]P), dibenz[a,h]anthracene (DB[a,h]A), benzo[g,h,i]perylene (B[g,h,i]P), indeno[1,2,3- cd]pyrene (InP), benzo[j]fluoranthene (B[j]Ft) and dibenzo[a,l]pyrene (DB[a,l]P). Briefly, shrimp´s edible portions were mechanically homogenized with a kitchen blender, 5 g were weighted and 10 mL of ACN were added to the shrimp sample homogenized, followed by 3 min of vortex. QuEChERS original was added and the mixture was again vortex for 3 min followed by centrifugation at 3500 rpm during 5 min. Then, 5 mL of extract was evaporated with nitrogen, resuspended with 333 μL of ACN, obtaining a concentration factor of 15 times. The extracts were filtrated through a 0.22 μm PTFE syringe filter and analyzed using high performance liquid chromatography (HPLC) with photodiode array (PAD) and fluorescence (FLD) detectors in series. Conclusions: The developed method using QuEChERS enable an efficient extraction of the 18 PAHs from homogenized shrimp samples in a short time, with minimal sample preparation; The amount of ƩPAHs ranged between 3.1 ng/g ww in sample from Matosinhos spring 2018 and 320.5 ng/g ww in sample from Sado aquiculture spring-s 2019; LMW-PAHs were predominant in all investigated sampling sites; B[a]P was only detected in one sample from Aveiro spring 2018 with 0.07 ng/g ww, also below the legislated value of 2 ng/g.