Heavy metals in sandy sediments of the Rías Baixas (NW Spain).

We studied the concentrations of certain heavy metals in the total and labile fractions of sandy sediments from four embayments situated on the northwestern coast of Spain. In order to compensate for the effects of the heterogeneity in texture of the different samples, data were normalized. Organic carbon was the most suitable normalizing factor for copper, lead and zinc in the total fraction and copper in the labile fraction, and iron was the most suitable for the other metals in both fractions. Enrichment of copper, lead and zinc in these sediments may have been caused by sewage contamination. The percentages of extractability for chromiun were remarkable.