Polychlorinated biphenyls (PCBs) in mussels along the Chilean coast.

GOAL, SCOPE AND BACKGROUND: Chile signed the Stockholm Convention, which establishes measures to reduce or eliminate Persistent Organic Pollutants (POPs) release into the environment, including the prohibition of their use and reduction of secondary products release, as well as management related with waste treatment. Among POPs, PCBs are a family of 209 compounds that differ in chlorine level and position. These substances present a wide variability in their physicochemical properties such as vapor pressure, water solubility and partition coefficients that determine their behavior and mobility within the different environmental compartments. In Chile, as in other countries, the use of these compounds were and continue to occur in diverse industrial applications such as dielectric fluid in transformers and condensers, with a use in Chile of approximately 550,000 L. A sampling of bivalves was performed during the years 2000-2002 in order to obtain information on the spatial distribution of the PCB levels for the length of the long Chilean coast (18 degrees-54 degrees South latitude, 4,200 km), contributing in this way to a better understanding of the PCB trend and eventual fractionation along latitudinal gradients in Chile, using as the bivalve Perumytilus purpuratus ('Chorito Maico') bioindicator. METHODS: The marine bivalves Perumytilus purpuratus were collected in 16 localities in northern and southern Chile. All samples were lyophilized, and PCBs (51 congeners) were extracted in a Soxhlet system (24 h) with n-hexane. Samples were cleaned in florisil and analyzed by GC-ECD. Blanks, certified reference materials and standards were processed along with the samples. RESULTS AND DISCUSSION: The results obtained for P. purpuratus indicate a congeneric distribution profile associated to a latitudinal gradient, and the statistical analysis of the congeneric composition of the PCBs indicated five groups in relation to the molecular weight (number of chlorines), where the lighter congeners were observed in areas corresponding to high latitudes with total PCB values of 298 ng/g dry weight. CONCLUSION: P. purpuratus turns out to be a good bioindicator of PCB levels in the coastal areas of Chile due to its wide distribution. The highest concentrations and the more volatile congeners were found in southern Chile, which could be the result of processes of long-range transport or illegal discharge occurring in such remote areas. These results confirm previous data from the International Mussel Watch project ten years ago. RECOMMENDATION AND OUTLOOK: Future studies are needed to confirm our findings utilizing another environmental matrix such as soil/sediments and air samples.

EROD activity and biliary fluorescence in Schroederichthys chilensis (Guichenot 1848): biomarkers of PAH exposure in coastal environments of the South Pacific Ocean.

Schroederichthys chilensis is a common shark that lives in Chilean coastal environments. In this work, the relationship between liver 7-ethoxyresorufin-O-deethylase dealkylation (EROD) activity and Fluorescent Aromatic Compounds (FAC) in bile of S. chilensis sampled in three bays with different degrees of pollution were performed including a reference area. Sixty individuals were collected, 20 for each site; (10 males and 10 females per site) livers and bile samples were obtained and immediately frozen. EROD activity and FAC were measured according to three standard methods. EROD activity and FAC were higher in polluted areas than in the reference area. Synchronous Fluorescence Spectra of the bile from the fish collected at the most polluted area showed a peak at 347nm representing a metabolite corresponding to 1-hydroxypyrene. The low EROD activity in the reference area is likely related to the low level of PAH in sediments. We propose that this species is a good indicator of exposure to FACs, since it presents a series of characteristics that make it suitable for monitoring PAH exposure in coastal zones.