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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Sedimentation rates and contamination levels by heavy metals at the shallow sedimentary columns from Santos estuary and bay, SP, Brazil

Full text
Author(s):
Tessler, M. G. ; Figueira, R. C. L. ; Mahiques, M. M. ; Fukumoto, Marina Midori [4] ; Ciapina, E. M. P.
Total Authors: 5
Document type: Journal article
Source: Journal of Coastal Research; v. SI 39, 2004.
Field of knowledge: Physical Sciences and Mathematics - Oceanography
Abstract

The coastal region of Santos (State of São Paulo, Southeastern Brazil), one of the most strategical Brazilian areas, where is placed the main port terminal has had an accelerated process of industrial and harbor improvement during the second half of the 20th century. An evolution of the depositional (sedimentary) processes in the context of this accelerated growth can be verified by sedimentation rates and the variation of heavy metal levels in the sedimentary columns from the upper estuary as well as in the Santos bay. The sedimentary changes were evaluated from the analysis of the texture as well as the variations of the concentrations of the metallic elements (Pb, Cu, Zn and others). The sedimentation rates were obtained by 210Pb and 137 Cs. The most representative sedimentary column from the area of the Santos bay (core S2T3) presented a segmentation of the sedimentation between 10 and 14 cm of depth. The value obtained for the uppermost sequence is about 0.91 mm.y-1 while the lower sequence presented a higher value rate (3.8 mm.y-1). This rate change representants a modification in the sedimentary pattern of the area, as one sequence of thin sandy sediments is replaced by the depositional of finder sediments (medium to fine silt). The higher sedimentation rate values from the area of the upper estuary, 4.0 mm.y-1 to 210Pb (Barnabe Island), correspondes to an approximate time range of 100 years. For 137Cs the sedimentation rate is 5.6 mm.y-1 which represents approximately the last 40 years. The increases of the concentration of the metallic elements in the sedimentary columns from these areas point to a change in the sedimentary dynamics and the concentration of the sediments starting at 10 cm. From this, it was possible to develop a history of the contamination by levels over that area. (AU)