Heavy Metals in Urban Channel Sediments of Aveiro City, Portugal

Citation

Pastorinho MR, Telfer T & Soares AMVM (2010) Heavy Metals in Urban Channel Sediments of Aveiro City, Portugal. In: Hamamura N, Suzuki S, Mendo S, Barroso C, Iwata H & Tanabe S (eds.) Biological Responses to Chemical Contaminants: From Molecular to Community Level. Interdisciplinary Studies on Environmental Chemistry, 3. Tokyo, Japan: TERRAPUB, pp. 197-204. http://www.terrapub.co.jp/onlineproceedings/ec/03/index.html

Abstract
The quantification of six metals: aluminum (Al), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and zinc (Zn), alongside with determination of organic carbon (OC) and calculations of C:N ratios was performed from surface sediments collected in urban channels of Aveiro City. The city is located along the shores of the Ria de Aveiro, a coastal lagoon, and until recently the city's channels and some of its oldest areas were tidally submerged by tidal floods. These events alongside with the impacts associated with urban development have contributed to create accumulation of metals in the sediments. Organic enrichment is generalized in the inner city channels whereas the opposite occurs in the outer channels. Significant correlations were established for the original dataset between Al and Cr > Zn > Cd (R2 = 0.79, 0.74, and 0.69, respectively), but not for Cu or Pb (R2 = 0.25, and 0.005, respectively), pointing to the prevalence of point sources of these two metals. Regressions of Metal/Al were used as the dataset normalizer allowing simultaneously the establishment of mathematical geochemical backgrounds and the consequent calculation of Enrichment Factors (EF). It was concluded that enrichment occurs in the inner city channels which export metals that are readily dispersed by tidal action.

Keywords
sediment; urban channels; metals; enrichment factors