Characterization of HeavyMetal Contamination in S

Authors: M MilHomens A M Costa S Fonseca M A Trancoso C Lopes R Serrano R Sousa

Publish Date: 2013/01/09

Volume: 64, Issue: 4, Pages: 617-631

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Abstract

Surface sediments were collected in August 2009 from 49 sites along the Minho estuary between Tui and Caminha and analyzed for grain size organic carbon Corg and total nitrogen Ntot contents and major silicon Si aluminum Al iron Fe calcium Ca magnesium Mg sodium Na potassium K titanium Ti and mangesese Mn and trace element arsenic As chromium Cr copper Cu mercury Hg lithium Li lead Pb rubidium Rb tin Sn and zinc Zn concentrations Factor analysis was used to decrease 22 selected variables into 4 factors accounting for 859  of the total variance explained suggesting distinct elemental sources or sediment components affecting their spatial distributions Although factors 1 detrital component elements strongly associated with fine Na Mg Ti Li Cr Cu Fe Al Zn Ca and As and coarsegrained sediments Si K Rb mean grainsize MGS and 3 Fe–Mn oxyhydroxide sediment component Fe Mn As fine fraction are interpreted as reflecting predominance of natural contributions factors 2 urban and industrial contamination sediment components Pb Hg organic carbon Corg total nitrogen Ntot and 4 components associated with contamination by nautical activities the association of tin Sn and calcium Ca seem to indicate anthropogenic contributions Nevertheless the influence of elemental contributions derived from tungsten W–Sn mineralizations and those resulting from mining activities can also contribute to the obtained geochemical associations and should be considered Spatial distribution of dominant factor scores shows the dominance of factors 2 and 4 between Tui and Vila Nova de Cerveira whereas samples dominated by factors 3 and 1 are found between Ilha da Boega and Seixas and in the Caminha areas respectively Despite the dominance of factor score 1 in the Caminha area the distribution pattern of dominant factor scores shows samples dominated by other factor scores that can be explained by dredging activities in this river sector that restore ancient sedimentary characteristics or expose contaminated sediments Through the identification of sample locations dominated by factors associated with contamination it will be possible to select them as priority areas where new environmental eg toxicity tests organic Sn compounds tracers of sewage contamination studies should be implemented in the futureThis work was financially supported by the Natura MiñoMinho Project 0234 NATURA MIÑO MINHO 1 E North PortugalGalicia Spain Territorial Cooperation Program POCTEP 2007–2013 We express our thanks to the crew of the RV Leopard Atlantic for their efficient work during the collection of sediment samples A special acknowledge to Carlos Antunes for allowing access to the Aquamuseu laboratory storage and sampling of surface sediments during the Minho09 cruise Special thanks for all UGMLNEG collaborators Ana Aranda Andreia Rebotim Catarina Cavaleiro Célia Santos Cremilde Monteiro Daniel Ferreira Fátima Abrantes Henrique Duarte Rúben Borges Sandra Mateus Teresa Rodrigues and Warley Soares who participated in the Minho09 cruise and help in laboratorial work We thank two anonymous reviewers for constructive suggestions and comments that improved the original version of the manuscript

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