Concerns over the sustained availability of fossil fuels and their impact on global warming and pollution have led to the search for fuels from renewable sources to address worldwide rising energy demands. Biodiesel is emerging as one of the possible solutions for the transport sector. It shows comparable engine performance to that of conventional diesel fuel, while reducing greenhouse gas emissions. However, the toxicity of products and effluents from the biodiesel industry has not yet been sufficiently investigated. Brazil has a very high potential as a biodiesel producer, in view of its climatic conditions and vast areas for cropland, with consequent environmental risks because of possible accidental biodiesel spillages into water bodies and runoff to coastal areas. This research determined the toxicity to two marine organisms of the water-soluble fractions (WSF) of three different biodiesel fuels obtained by methanol transesterification of castor oil (CO), palm oil (PO), and waste cooking oil (WCO). Microalgae and sea urchins were used as the test organisms, respectively, for culture-growth-inhibition and early-life-stage-toxicity tests. The toxicity levels of the analyzed biodiesel WSF showed the highest toxicity for the CO, followed by WCO and the PO. Methanol was the most prominent contaminant; concentrations increased over time in WSF samples stored up to 120 d.

The toxicity of surface waters and interstitial waters from sediments were determined at six study sites in Todos os Santos Bay, Bahia, Brazil, to evaluate the possibility of chronic environmental impact induced by 40 years of exposure to the local petroleum industry. Samples collected from four sites associated with the extraction, transportation and re®nement of petroleum, and from two control sites, were tested at seven three-month intervals. Toxicological assays using acute mortality of brine shrimp (Artemia salina) nauplii and chronic abnormalities of sea urchin (Echinometra lucunter) and mangrove oyster (Crassostrea rhizophorae) larvae were employed. Friedman non-parametric analyses of variance integrated seasonal variations in species response patterns and revealed signi®cant differences among the study sites. Ranging the among-site variations for each organism in each sampling period, on a scale from 0.00 (minimum response) to 1.00 (maximum response), permitted the calculation of a single mean value for each species and the ordination of the sites on a qualitative scale of relative impact. Although the ordinations varied with species, the reduction of three species response patterns to a common relative scale also permitted their integration into a single multispecies ordination of the study sites. A cluster analysis of the six sites and two aquatic substrates, based on their toxicity to all three species, illustrated the similarities and differences between locations.

The toxicity of surface waters and interstitial waters from sediments were determined at six study sites in Todos as Santos Bay, Bahia, Brazil, to evaluate the possibility of chronic environmental impact induced by 40 years of exposure to the local petroleum industry. Samples collected from four sites associated with the extraction, transportation and refinement of petroleum, and from two control sites, were tested at seven three-month intervals. Toxicological assays using acute mortality of brine shrimp (Artemia salina) nauplii and chronic abnormalities of sea urchin (Echinometra lucunter) and mangrove oyster (Crassostrea rhizophorae) larvae were employed. Friedman non-parametric analyses of variance integrated seasonal variations in species response patterns and revealed significant differences among the study sites. Ranging the among-site variations for each organism in each sampling period, on a scale from 0.00 (minimum response) to 1.00 (maximum response), permitted the calculation of a single mean value for each species and the ordination of the sites on a qualitative scale of relative impact. Although the ordinations varied with species, the reduction of three species response patterns to a common relative scale also permitted their integration into a single multispecies ordination of the study sites. A cluster analysis of the six sites and two aquatic substrates, based on their toxicity to all three species, illustrated the similarities and differences between locations. Interstitial waters were more toxic, revealing an integrated ordination of Station 6 --< Station 5 --< (Station 3= Station2) --< (Station 4 = Station 1). The ordination based on surface waters was Station 6 -< Station 5 --< (Station 2 = Station 1 = Station 3) < Station 4. In combination, the three procedures served efficiently for the description and inferential testing of the multispecies responses and, complemented with additional data on species diversity and chemical contamination of the sediment, confirmed the existence of chronic impact within the study area.

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