Cu, Pb AND Zn DISTRIBUTION IN NEARSHORE WATERS IN SAN JORGE BAY, NORTHERN CHILE
An extensive spatial survey metal content to study the spatial distribution of Cu, Pb and Zn concentration in nearshore waters of San Jorge Bay, along the coast of Antofagasta City, Chile was carried out located near the Atacama desert, which represent the largest populated urban settlement in northern Chile (~ 260,000 inhabitants). The coastal zone of this area is under an intensive use as discharge location of pollutants of different sources. Dissolved Cu varies between 0.97 to 1.65 mug l-1, in the southern part of the study area and in front of an industrial discharge, respectively. The dissolved Pb shows a narrow concentration range (0.019 to 0.029 mug l-1) and Zn content varies between 1.7 mug l-1 in the northern part of the study area to 2.0 mug l-1, in front of the industrial discharge zone. The particulate Cu fraction pattern is similar to that of dissolved Cu, with concentrations varying between 126.8 mug g-1 and 467.2 mug g-1. Particulate Pb ranges between 9.8 to 33.8 mug g-1, and Zn 149.7 to 403.5 mug g-1. The spatial distribution of both, dissolved and particulate Cu, Pb and Zn results from local industrial sources located within Antofagasta City and San Jorge Bay current system that dilutes them as the water moves to the north. The particulate fraction is the dominant form of the metals, probably due to the dust coming from the Atacama desert, representing an important natural source of these metals to the water of the bay, particularly in those locations far from local inputs.