Polycyclic aromatic hydrocarbons in sediments from Sontecomapan Lagoon, Veracruz, Mexico

Resumo

In this study a determination of the concentrations of 15 polycyclic aromatic hydrocarbons (PAH) in surface sediments from Sontecomapan Lagoon, Veracruz was made; these compounds were evaluated by means of gas chromatography using capillary columns of high resolution and flame ionization detection (GC-FID). During the period 1991 to 1992, it strengthen that exist differences between dry and rainy season, dry period showed the highest total PAH's concentrations ranged from 25.42 to 49.49 µg/g of dry sediment and in rainy period these ranged was recorded from 10.15 to 21.98 µg/g. In descending order, of the individual compounds of PAH's in dry season were: Chrysene (49.66 µg/g) > Benzo(a)anthracene (14.57 µg/g) > Benzo(b)fluoranthene(8.23 µg/g) > Benzo(k)fluoranthene(5.53 µg/g) > Anthracene(5.44 µg/g) > Pyrene(5.41 µg/g). For rainy season were: Chrysene (27.92 µg/g) > Benzo(a)pyrene (2.71 µg/g) > Benzo(k)fluoranthene (2.62 µg/g) > Benzo(a)anthracene (2.58 µg/g) > Benzo(b)fluoranthene (2.25 µg/g) > Pyrene (2.02 µg/g). The presence of 4, 3 and 5 benzene rings in PAH's suggests that these compounds are primarily of pyrogenic origin, this is the result of surrounding vegetation fires, the lubricants, and gasoline. PAH's goes into lagoon system through river discharges, by tidal action from the coast and from atmospheric transport.