Abstract

Polycyclic aromatic hydrocarbons (PAHs) andpolychlorinated biphenyls (PCBs) are ubiquitous pollutants inthe environment. Due to their physical-chemical properties,PAHs and PCBs can be accumulated in organic matrices suchas living organisms, soil and sludge. Their toxicity andmutagenicity is a serious concern. In many cases an effectivestrategy to assess the pollution of water streams is to detectthese compounds using biofilms, sediment and sludge as passivesamplers.<br>However, the absorption of hydrophobic compounds inbiofilms is a reversible mechanism. The molecules of a specificpollutant can be desorbed back into the water column whenspecific conditions have changed. Furthermore, those moleculescould be biodegraded by the microorganisms living inside thatbiofilm.<br>Thus, the pollutant is not going to remain detectable insidethat biofilm sample permanently, but only for a limited time.This is due to the memory effect.<br>The aim of this work is to retrieve the most relevant data onthis subject and build from scratch a simplified model. This willhelp to understand how microbial biofilms can influence thedistribution of PAHs and PCBs in water streams.<br>Absorption, desorption and biodegradation are the threemain mechanisms considered for the calculations.<br>This information will surely stimulate further research onthis topic. Phenanthrene and pyrene were chosen as referencecompounds for PAHs and Kaneclor 300, Aroclor 1260 andother tri- and tetra- chlorinated byphenils were chosen asreference for PCBs.