The difference of PAHs concentration in calibration control before and after sorption
experiments were minimal, so the edge effect of the 8-mL vials on sorption results was negligible. Because of a minimal sorption by the vials (i.e., aminimal edge effect of the 8-mL vials), and negligible losses by evaporation, biodegradation and photodegradation, the amount-sorbed of PAHs to biosorbent was calculated by mass difference between nominal concentration without sorbent and with sorbent in aqueous solutions.