Avaliação de risco ecológico da contaminação de sedimentos e material dragado da região do porto do Mucuripe - Ce através de métodos ecotoxicológicos

Abstract

In harbor areas, sediment contamination promotes environmental impacts, economic losses and ecological risks. In some cases these impacts compromise dredging and oceanic disposal of the contaminated sediment. In this scenario, the Ecological Risk Assessments aim to determine ecological impacts caused by anthropogenic activities, which can induce adverse effects on individuals, populations, communities and ecosystems in order to assist in identifying environmental problems and the generation of scientific basis for management initiatives. Ecotoxicological approaches estimate the effects of contaminants in environmental compartments (or not) under non-target organisms, assisting, thus, in the type of exposure and the effects evaluations necessary for risk characterization. In this context, this research presents a study on Ecological Risk Assessment of sediment contamination and dredging operations of the Mucuripe Harbor using the following ecotoxicological approaches: (1) integrated assessment of sediments through the Sediment Quality Triad approach; (2) biomarkers responses in the bivalve mollusk Anomalocardia brasiliana exposed to sediments and dredged material in the Mucuripe Harbor; and (3) obtaining the range of biological effect corresponding to the site-specific sediment quality values from samples collected in the Harbor area. The results herein showed the influence of contamination sources on sediment toxicity, benthic community and biomarker responses of organisms exposed in the field and in the laboratory. By obtaining site-specific sediment quality values, it was possible to observe that the biological effects occur at low concentrations compared to reference values presented in national and international guidelines, indicating, thus, failure of these values in predicting impacts related to toxicity. Also, the results presented in this study provide information concerning the knowledge of sediment quality in harbor areas in the Brazilian Coast, especially in the Ceará state.