The shrimp are lengthily washed with distillated water and after, the shells are removed. The shrimp were kept at − 20 °C and lyophilized. The lyophilized bivalves mollusk is succumbed to extraction by ultrasonication in dichloromethane. The system is centrifuged, the dichloromethane is extracted and the extraction process repeat two more times.(ref) The extracts are merged and concentrated in rotary evaporator. After that it is submitted to clean by using aluminum oxide column. The column is eluted hexane by removing in order to the organic segment. The organic segment is concentrated and fractionated by using an activated silica gel column. The elution column firstly use with hexane to gain the aliphatic hydrocarbon fraction. Additionally, the elution is hexane/ dichloromethane (8:2) to obtain the PAHs [ref]. All the extracts are concentrated, transferred to an auto-sampler microvial and blow-down by using N2 to practically aridness. (ref) The BaP extracts is completed with pyrene-d10 standard solution All standards are added to the samples before gas chromatographic analysis.