Background Concentration of Copper and Cadmium in Water from a High Industrialized and Urban Coastal System (Baixada Santista, Brazil)—Contribution to a Monitoring Program

The Baixada Santista coastal region is well known in the context of the high atmospheric, soil and aquatic pollution levels derived from port, industrial, domestic and urban activities existent there, mainly in function of the Cubatão industrial pole and port of Santos. The contamination by trace metals in this region is rarely measured in water column when compared with metal determinations in sediment studies. This study aims to evidence the levels of dissolved copper and total cadmium concentrations in estuarine and seawater waters using electrochemical analysis as a chronopotentiometric stripping polarography, which could improve the environmental monitoring program. The study was performed in the Bay of Santos reaching two estuarine channels (Santos and São Vicente Channels) in two tide periods in summer 2001. This region is influenced by terrestrial and anthropogenic inputs of trace metals to seawater. The results showed that dissolved copper and total cadmium in water presented the maxima concentrations of 45.4 nM and 2.6 nM respectively. They not reached the limits proposed by Brazilian Environmental Law (CONAMA), that indicate, as reference, a maximum of 123 nM and 350 nM for dissolved copper and total cadmium, respectively and, considering seawater coastal system (salinity > 30, class 2) and also brackish water (class 2). Although the values were under the maximum recommended for each metal, the concentrations were not negligible in relation to the other polluted areas in the world. The values distribution along the system showed a progressive increase in direction to the inner part of the system that naturally compromises the local biota whose is more exposed to the bioaccumulation processes, and this data corresponds to an important reference preterit value to the monitoring program. The trace metal bioaccumulation by mangrove vegetation and by the biota in the internal part of the estuarine channels increase the risk of the poorly population that living in the internal part of the estuary, used to the seafood consumption. The contribution of this study is important to guide the protective policies destined to recuperate the natural conditions of this system, mainly considering that in the decade 1980, there was a case of toxic contamination, causing hydrocephaly in newborns. It proves the existence of risks to the human health and to the balance of the ecosystem, even with the decrease of pollution after that, the environmental evaluation needs to know the background values to guide environmental protection.

Sedimentary and Geochemical Aspects of a Refinery Impacted Coastal Area: A Case Study of the Todos os Santos Bay (Bahia, Brazil)

The present study was performed in the northeast portion of the Todosos Santos Bay, Bahia State, Brazil, an area under influence of the Landulpho Alves-Mataripe (RLAM) refinery effluents. The aim of this work is to evaluate the modern sedimentary processes based on grain-size analysis, calcium carbonate and sedimentary organic matter concentration and behavior considering the possible effects of the petroleum industry’s refining on these sediments. The concentrations and variations of the three main constituents of organic matter (total organic C, total N and organic P), and the resulting elemental ratios (C/N, C/P and N/P), were studied on a seasonal spatial and temporal scale (winter 2004 and summer 2005), therefore subsidizing the environmental analysis, especially in regards to the benthic ecosystem. Fifty samples from twenty-five sampling stations were collected with a grab sampler. Well sorted sandy sediments are observed in coastal sampling stations and in the Caboto channel. The recent deposition of fine sediments was observed especially in the west and central portions of study area. However, these spots contain the highest percentages of organic material, which do not present significant seasonal and spatial variations, revealed by the values of total organic C which reach values of up to 3.1%, total N (0.01% to 0.15%) and the organic P contents that reach a maximum of 15.9 μmol·g-1. In general, the elemental ratios indicated continental organic matter inputs, probably derived from human activities.