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


CONCLUSIONS
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.


CONCLUSIONS
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.


CONCLUSIONS
Future studies are needed to confirm our findings utilizing another environmental matrix such as soil/sediments and air samples.
Mendoza
Gonzalo
G
Aquatic Systems Research Unit, EULA-Chile Environmental Sciences Center University of Concepción, Chile. rmendoza@udec.cl
Gutierrez
Luis
L
Pozo-Gallardo
Karla
K
Fuentes-Rios
Daniel
D
Montory
Monica
M
Urrutia
Roberto
R
Barra
Ricardo
R
D000818:Animals; D002677:Chile; D004784:Environmental Monitoring; D049879:Mytilidae; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D025341:Principal Component Analysis; D012623:Seawater; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls