Site investigation on heavy metals contaminated ground in Estarreja - Portugal

Owing to its five decades in the chemical industry, Estarreja is one of the most important industrial areas in Portugal. intensive industrial activity along with both direct discharge of the effluents into natural water strea ms and uncontrolled waste disposal on the ground has, throughout the years, had strong impact on health and welfare. Recently an association between i ndustry and local authorities was created - ERASE. The main goal for this a ssociation is to find, in co-operation with the Portuguese Environmental Mi nistry, a cost-effective solution to deal with the soil/sediments contamina tion and solid waste problem. The ERASE association planned to build a landfill for both solid waste and contaminated soil/sediments disposal. In order to determine more accurately the volume of material to be disposed of in the landfill, a site investiga tion was carried out during September/November 1998. The site investigation consisted mainly of systematic soil sampling at shallow depths, both withi n the industrial area and along the natural water streams. The site investigation results revealed high concentrations of toxic pollut ants, mainly heavy metals (namely As, Hg, Ph and Zn), in the soil of the in dustrial area. Much higher concentrations were found in the sediments of th e water streams. several kilometres away from the industrial complex (the p ollution source area). In most cases, concentration increases with depth, reaching groundwater. Th erefore the site investigation programme carried out could not determine th e full extent of the contamination. Consequently, further studies were stro ngly recommended, which should include a wider and deeper investigation are a and groundwater sampling. (C) 2001 Elsevier Science B.V. All rights reser ved.