Letters a group of PAHs are present in the plant extract and contributed to the light-mediated antiviral activity. We believe that the source of the PAHs was not from contamination in the purification procedure. With separation and analytical techniques capable of purifying trace components, it is more of a possibility that impurities from materials used in the processing can be accumj.ilated and be found in an identifiable quantity. The major solvent used in this procedure consisted of a mixture of hexanes. The impurities remaining from the evaporation of four liters of hexanes under reduced pressure were submitted for NMR and the spectrum obtained was not complex enough to indicate the presence of PAHs. Polycycic aromatic hydrocarbons have been found in foliage as well as in crops (6). PAils are generated by the incomplete combustion of fossil fuels and are found throughout the environment. If the occurrence of 245-261.

PAHs were measured in sediments and mussels (Mytilus chilensis) from Carboneros and Puerto Claro, located in Corral Bay, Valdivia. According to the ratio of phenanthrene/anthracene and fluoranthene/pyrene concentrations, these sites are medium polluted with PAHs originating mainly from pyrolytic sources. Fluoranthene was the major component measured in mussels (3.1-390 ng g(-1) dry weight) and sediments (6.9-74.1 ng g(-1) dry weight). In general, mussels were mainly exposed to the dissolved fraction of the lower molecular weight PAHs (tri- and tetra-aromatics) while the higher molecular ring systems (penta- and hexa-aromatics) were more bioavailable to sediments. Mussel PAHs content was relatively constant, with the exception of the 1999 summer season (March), when higher concentration values were found in both sites; however, PAHs residues in sediments showed a temporal variation.

PAHs and PCBs were measured in the mussel Perumytilus purpuratus (Lamarck) collected from three different sites along the coast of Valdivia and Valparaiso, South-Central and Central Chile, respectively. Pollution at these sites is considered low with PAHs originating mainly from pyrolytic sources according to the Phenanthrene/Anthracene and Fluoranthene/Pyrene ratios. Temporal variation of PAHs was observed in Valdivia, while site variation was observed along the

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