Potential of the polychaete Sabella spallanzanii as bioindicator for PHAs

Abstract

Every year 230.000 t of polycyclic aromatic hydrocarbons (PHAs) enter the marine environment, resulting ubiquitously distributed world‐wide. These compounds are aromatic molecules of special concern because of their toxic and carcinogenic properties. The two main sources of PHAs in the environment are fossil fuels, mainly crude oil, and the incomplete combustion of organic materials such as wood, coal and oil. They enter the sea by both atmospheric and aquatic routes. As a consequence of their hydrophobic nature, in aquatic environments PHAs rapidly tend to associate with particulate matter and sediments represent the most important reservoir. Animal and aquatic plants can accumulate PHAs from the environment even when these pollutants are present at very low concentrations; thus marine organisms are important bioindicators of organic pollution in marine ecosystems. In the present study the level of PHAs in the sessile filter‐feeder polychaete Sabella spallanzanii was assessed. In particular, the concentration of PHAs was determined in sediments and in polychaetes (body and tube) collected from three Sicilian ports, subject to different anthropic pressure. A transplanting experiment was also performed. Organisms were transplanted from less contaminated to more contaminated sites and viceversa. In addition, organisms were transplanted into their original site as control for the possible effects of transplantation. At the start and the conclusion of the 1 month‐transplanting experiment all organisms were analysed for PAH concentrations using a gas‐cromatograph. The accumulation in the bodies and tubes of polychaetes was related to the concentration of pollutant present in the sediments. Differences were observed between sites and within each site between transplanted and control organisms. These results have implications for the role and possible use of this polychaete as a bioindicator.