Determination of hydrocarbons in sediments from rain drainage channels Pelotas/RS

Abstract

The quality of surface water, infiltration and groundwater is influenced by pollutants collected from waterproofed surfaces and transported by urban runoff. Among the constituents of the urban runoff hydrocarbons are considered as geochemical indicators and can infer about the different sources of contamination. These compounds are readily adsorbed to the particulate material being accumulated in the sediments that act as a reservoir for hydrophobic contaminants. The objective of this work was to evaluate the impact of the hydrocarbon cargo transported by the urban runoff. In this way, a drainage channel was studied that crosses the urban area of Pelotas/RS, evaluating the levels of n-alkanes, TPH (total petroleum hydrocarbons) Aliphatic, Unresolved Complex Mixtures (UCM) and their connections with sources of contamination.TPH values ranged from 4.2 x 105 μg kg-1 to 9.8 x 105 μg kg-1. Total aliphatic content indicated chronic contamination. Samples showed predominance of C23 to C35 n-alkanes at all points, ranging from 1.8 x 104 to 7.8 x 104 μg kg-1. The results pointed to mixed sources of contamination Hydrocarbon levels (HTP, aliphatic and n-alkanes) were considered high, confirming the impact of urban drainage on the city's drainage system and its consequent impact on water resources.