Assessment of anthropogenic metals in shipyard sediment in the Amazon delta estuary in northern Brazil.

Abstract

Shipyard activities have contributed to the release of anthropogenic metals in sediment in the Amazon delta estuary, but no studies of the issue have been carried out in northern Brazil. This study evaluated the sediment that is under the influence of shipyard activities in the Guajará Bay and in the channel of the Maguari River, in Belém, Pará (PA) state, northern Brazil. Sediment samples were collected in the vicinity of the shipyards, while samples of paint and metal fragments were collected from hulls of abandoned vessels. Metals under analysis were Cu, Zn, Pb, Ni, Cr, Ba, V, Li, Fe and Al. Mean Cu concentrations found in the sediment in two shipyards - 28.3mgkg-1 and 41.0mgkg-1 - were above the threshold effect level (TEL) for the amphipod Hyalella azteca. The highest concentrations of metals found in paint fragments from abandoned vessels were 29,588mgkg-1 Ba, 9,350mgkg-1 Zn, 1,097mgkg-1 Pb and 548mgkg-1 Cr. This fact suggests that vessel abandonment is a major source of contamination in shipyard areas. The principal component analysis (PCA) showed that most metals under study are closely related to sediment contamination in the shipyards. Geoaccumulation index and screening concentrations of inorganic contaminants for metals in freshwater ecosystems confirmed that a shipyard was contaminated by copper. Results may support further studies of contamination and application of waste management to shipyards and vessel graveyards around the world.