TEMPORAL AND SPATIAL TRENDS OF TOTAL ALIPHATIC HYDROCARBONS OF DIESEL RANGE AND TRACE ELEMENTS IN SEDIMENTS AND MUSSELS OF THE CORRAL BAY AREA, VALDIVIA, SOUTH CENTRAL CHILE

Abstract

Sediments and mussel specimens of Mytilus chilensis were analyzed for organic pollutant fingerprints and heavy metals in the Corral Bay area of Valdivia, South Central Chile during the period 2003-2004. GC-MS analysis show hydrocarbon fingerprints corresponding mainly to mixed inputs of aliphatic hydrocarbons of the TPH-diesel fraction and biogenic hydrocarbons, indicating low to medium contamination by petroleum hydrocarbons with high biodegradation of petroleum in sediments at Las Coloradas, La Escuela and Corral Bay (C 17 /Pri < 1 and C 18 /Phy < 1). Mussel TPH fingerprints show weathered hydrocarbons resulting in a zone of increased concentration of cyclic respect to acyclic aliphatic components (UCM), indicating the presence of petroleum hydrocarbons. No temporal variation the in concentration of TPH-diesel found in sediments as well as mussels were observed except for samples collected during January 2004. TPH concentration levels in the sediments varied from 0.4 µgg-1 to 33.8 µgg-1 d.w. whereas in mussels varied between 61 µg g-1 and 287 µgg-1 d.w. Heavy metals were also analyzed by atomic absorption spectrometry and low concentration as well as no seasonal variations of concentration were found in mussels at each sampling point and a relatively even distribution of metals among stations was observed. Maximum concentrations in all sampling points of sediments were found for Fe (24128-43791 µgg-1) and Mn (181-388 µgg-1) while the minimum concentration was found for Pb (nd-12 µgg-1). According to the Sediment Quality Guidelines (SQGs-NOAA), the concentration levels of Cu and As in all sediment sampling points are above the “Effects Range-Low” (ERL), indicating that there may be a probable toxicity effect over the biota and attention must be paid on a moderate range of priority.