Effects of petroleum and its derivatives in benthic communities at Baía de Todos os Santos/Todos os Santos Bay, Bahia, Brazil

Abstract

Benthic community structure and diversity have been investigated to assess stress conditions of Todos os Santos Bay, Bahia, Brazil, as a possible result of the extraction, transportation and re®ning of petroleum, activities carried out in this area for more than 40 years. Samples were collected over two years, at four stations under the direct in¯uence of stress-causing activities and at a control station. Benthic indices were calculated for all intertidal communities. The density, relative abundance, frequency of occurrence, diversity, similarity and occurrence of preferential species were recorded. Linear correlation indices were calculated to establish comparisons between ecological parameters of the studied communities and concentrations of heavy metals, hydrocarbons, petroleum pollution indicators and sediment mud percentages. The polychaete worms were the dominant group Ð up to 92% dominance in the community within the in¯uence of re®nery activities. Diversity indices indicated signi®cant stress related spatial gradients tied to petroleum. The re®nery sample station showed notable differences in its biodiversity ®gures compared to the other stations. Quantitative benthic indices showed negative correlations between the presence of cadmium, hydrocarbons, n-alkanes and the unresolved complex mixture in the intertidal zone marine sediments.

Baía de todos os santos: aspectos oceanográficos

“…Martin et al (1986) deduziram a existência de movimentos verticais holocênicos, com base na distribuição de depósitos quaternários no interior da Baía de Todos os Santos. Mais recentemente, Carvalho (2000), Lessa et al (2000), Lessa (2005) e Cirano e Lessa (2007) reafirmaram, principalmente com base em evidências apresentadas em trabalhos mais antigos, a crença em movimentos tectônicos recentes como um dos principais fatores a modelarem a baía.…”

“…Na ocasião, a desembocadura do rio Paraguaçu situava-se muito provavelmente em torno desta "profundidade", por analogia ao que foi verificado em outros rios menores da costa da Bahia, a exemplo dos rios Almada e Itapicuru (Dominguez, 2007 ocorrido. O Paraguaçu é um rio que transporta muito pouco sedimento, a ponto de até hoje não ter conseguido preencher a Baía de Iguape, onde deságua, tendo construído apenas um pequeno delta de cabeceira de baía (Carvalho, 2000 (Cruz, 2008) (Figuras 13b e 13c). Recifes de corais estão presentes também na face da ilha de Itaparica voltada para a entrada da baía, onde se desenvolveram sobre as lajes (terraços de abrasão) que bordejam a ilha.…”

Benthic macrofauna structure in the northeast area of Todos os Santos Bay, Bahia State, Brazil: patterns of spatial and seasonal distribution

“…Tavarez et al (1988) and Porte et al (1990) used the bivalve Anomalocardia brasiliana to monitor hydrocarbons, PCBs and DDTs at several points of the TSB intertidal zone. More recently, Peso-Aguiar et al (2000) studied the effect of petroleum on the benthic communities of that same region, concluding that the activities of oil refining carried out in the region were the main sources of stress to the intertidal aquatic fauna. Barroso et al (2002), who studied the trophic structure of polychaetes, and more recently Venturini and Tommasi (2004), that investigated the distribution of macrofauna on unconsolidated bottoms of the northeastern portion of TSB, reached the same conclusion.…”

Protein model for pollutant uptake and elimination by living organisms and its implications for ecotoxicology

“…Sediments in aquatic ecosystems accumulate pollutants, with concentrations often many orders of magnitude greater than in associated water (Meador et al 1995, Nipper 2000, Anderson et al 2001, Burd 2002, Fent 2003. In aquatic ecosystems, benthic organisms are well-suited indicators of environmental contamina-tion (University North Carolina 1994, Krantzberg et al 2000, Anderson et al 2001, because their usually restricted mobility makes it difficult for them to escape contaminated conditions (Peso-Aguiar et al 2000). Sediment-sorbed contaminants may profoundly impact biological communities (Morissey et al 1996, Ferraro & Cole 1997, Grumiaux et al 1998, Burd et al 2000, Peso-Aguiar et al 2000, Stewart et al 2000, Xu et al 2002, with adverse ecological changes accumulating through time (Grumiaux et al 1998).…”

“…In aquatic ecosystems, benthic organisms are well-suited indicators of environmental contamina-tion (University North Carolina 1994, Krantzberg et al 2000, Anderson et al 2001, because their usually restricted mobility makes it difficult for them to escape contaminated conditions (Peso-Aguiar et al 2000). Sediment-sorbed contaminants may profoundly impact biological communities (Morissey et al 1996, Ferraro & Cole 1997, Grumiaux et al 1998, Burd et al 2000, Peso-Aguiar et al 2000, Stewart et al 2000, Xu et al 2002, with adverse ecological changes accumulating through time (Grumiaux et al 1998). Such changes may be indicators of adverse toxic effects not identifiable by chemical tests (Stewart et al 2000, Roach et al 2001.…”