EVOLUTION OF ENRICHMENT OF SEDIMENTS BY TRACE METALS (Ni AND Zn) IN A DAM OF URBANIZED WATERSHED

• Main Authors: Poleto Cristiano, Cardoso Alice Rodrigues
• Format: Article
• Language: English
• Published: Romanian Limnogeographical Association 2013-05-01
• Series: Lakes Reservoirs and Ponds
• Subjects: urban sediments; urbanization; zinc; nickel
• Online Access: http://www.limnology.ro/Lakes/2013/201307104.pdf

Sediments represent and provide a response to the condition of the environmental system in which they are found, acting as a point for deposition of contaminants. Upon developing studies of sediment columns, it is possible to obtain the historic records of substances arising from activities developed in the watershed over recent years. In this context, the present study investigates the enrichment of the sediments produced in an urban residential catchment area by the trace metals zinc and nickel. The sediment fraction smaller than 63 μm was analyzed in three sediment cores from the dam. Chemical analyses verified the concentration of trace metals by the acid digestion method EPA 3050. In carrying out analyses of the evolution of urban settlement in the watershed, the values corresponding to natural and human-impacted areas were determined through the use of different remote sensing products: aerial photographs (from 1972 and 1991) and high resolution satellite images (from 2003 and 2008). Natural areas were reduced in four decades, and population density in already human-impacted areas proved to be an important factor for understanding the urbanization process of the area. All sediment samples analyzed showed Zn and Ni concentrations above the local background value and with a pattern of growth