Water and sediment toxicity in a river affected by former mining residues

A bacia do Rio Ribeira de Iguape foi palco de intensa atividade de mineração de chumbo e, como resultado, estima-se que o \ud rio Ribeira de Iguape tenha recebido a descarga de aproximadamente 5,5 t/mês de materiais ricos em As, Ba, Cd, Pb, Cu, Cr e \ud Zn. No presente trabalho, foi analisada a toxicidade de sedimentos e águas coletados ao longo do rio com o intuito de avaliar \ud a qualidade ambiental, tendo sido realizadas 3 campanhas de coleta, entre 2009 e 2010. Os testes de toxicidade aguda foram \ud conduzidos com o cladócero Daphnia similis, utilizando as amostras brutas de água e a exposição aos sedimentos pela interface \ud sedimento-água. Os resultados indicaram, em geral, ausência de toxicidade, tanto para sedimentos quanto para águas, com \ud efeitos tóxicos agudos registrados apenas episodicamente (toxicidade marginal). Tais resultados são coerentes com as baixas \ud concentrações de metais em águas e sedimentos indicadas na literatura, porém diferem do monitoramento feito pela agência \ud ambiental estadual, que tem registrado toxicidade crônica. Essa toxicidade aguda eventual indica, ainda, que embora a qualidade do Rio Ribeira de Iguape esteja sendo recuperada, as condições ainda não estão totalmente controladas.The Ribeira de Iguape River basin received intense mining activities for lead exploiting and, as a result, the river received the \ud discharges of estimated amounts of 5.5 tons/month of material rich in As, Ba, Cd, Pb, Cu, Cr and Zn. In this article, the toxic-ity of waters and sediments collected in Ribeira de Iguape River was assessed aiming to estimate environmental quality. Three \ud sampling campaigns were conducted, from 2009 to 2010. Toxicity tests with the cladoceran Daphnia similiswere done for water \ud samples and for sediments, in this case using sediment-water interface exposure. Results showed in general absence of toxicity \ud for sediments and waters, and only eventually were acute effects registered (marginal toxicity). Results are consistent with the \ud conditions indicated by the literature, of low concentrations of metals in waters and sediments; however they differ from the \ud monitoring made by the state environmental agency, which registered chronic toxicity. The occurrence of eventual acute toxicity \ud indicates that although Ribeira de Iguape River quality is being restored, conditions still are not totally under control.FAPESPFundação de Amparo a Pesquisa do Esta-do de São Paulo (FAPESP) - Processos n. 2008/54607-5 e n. 2009/52762-

Developing a protocol whole sediment toxicity testing with the polychaete Armandia agilis

Sediments constitute a key compartment of coastal and marine ecosystems. They also constitute the ultimate sink for most of the chemical substances and a source of contamination to the benthic fauna. In this study, we aimed to develop a protocol for acute toxicity tests using the polychaete Armandia agilis as a model species. To achieve that, we evaluated the species tolerance to the salinity of overlying water (in the presence and absence of sediment), the tolerance to sediments with different particle sizes, the sensitivity to reference substances (potassium dichromate – K2Cr2O7, zinc sulfate – ZnSO4; and Sodium Dodecyl Sulfate - SDS), and the responses to clean and contaminated sediments. The species survives in several latitudes on the American coast (North Carolina, Gulf of Mexico, and South-Southeast of Brazil) in different haline conditions (above 20) in typically sandy textures. In Ilhabela (SE Brazil), the species was available throughout the year. The LC50-48h values calculated to the K2Cr2O7, ZnSO4, and SDS, were 20.94 (33.38-14.04); 4.25 (7.66-2.98); 4.90 (6.59-3.84) mg L-1 respectively; thus A. agilis can be considered as sensitive as other benthic organisms. The responses of A. agilis to environmental sediments were similar to those exhibited by the amphipod Tiburonella viscana, showing that this polychaete is responsive to contaminated sediments. Armandia agilis can be considered a promising organism to be used in sediment toxicity tests

Cumulative influences of a small city and former mining activities on the sediment quality of a subtropical estuarine protected area

This study aimed to evaluate the sediment quality in the estuarine protected area known as Canan,ia-Iguape-Peruibe (CIP-PA), located on the southeastern coast of Brazil. The study was designed considering possible negative effects induced by the city of Canan,ia on the sediment quality of surrounding areas. This evaluation was performed using chemical and ecotoxicological analyses. Sediments were predominantly sandy, with low CaCO3 contents. Amounts of organic matter varied, but higher contents occurred closer to the city, as well as did Fe and Total Recoverable Oils and Greases (TROGs) concentrations. Contamination by Cd and Cu was revealed in some samples, while concentrations of Zn were considered low. Chronic toxicity was detected in all tested sediments and acute toxicity occurred only in sediments collected near the city. The principal component analysis (PCA) revealed an association among Cd, Cu, Fe, TROG, fines, organic matter, CaCO3, and chronic toxicity, whereas acute toxicity was found to be associated with Zn and mud. However, because Zn levels were low, acute toxicity was likely due to a contaminant that was not measured. Results show that there is a broad area within the CIP-PA that is under the influence of mining activities (chronic toxicity, moderate contamination by metals), whereas poorer conditions occur closer to Canan,ia (acute toxicity); thus, the urban area seems to constitute a relevant source of contaminants for the estuarine complex. These results show that contamination is already capable of producing risks for the local aquatic biota, which suggests that the CIP-PA effectiveness in protecting estuarine biota may be threatened

Toxicidade de águas e sedimentos em um rio afetado por atividades mineradoras pretéritas

The Ribeira de Iguape River basin received intense mining activities for lead exploiting and, as a result, the river received the discharges of estimated amounts of 5.5 tons/month of material rich in As, Ba, Cd, Pb, Cu, Cr and Zn. In this article, the toxicity of waters and sediments collected in Ribeira de Iguape River was assessed aiming to estimate environmental quality. Three sampling campaigns were conducted, from 2009 to 2010. Toxicity tests with the cladoceran Daphnia similis were done for water samples and for sediments, in this case using sediment-water interface exposure. Results showed in general absence of toxicity for sediments and waters, and only eventually were acute effects registered (marginal toxicity). Results are consistent with the conditions indicated by the literature, of low concentrations of metals in waters and sediments; however they differ from the monitoring made by the state environmental agency, which registered chronic toxicity. The occurrence of eventual acute toxicity indicates that although Ribeira de Iguape River quality is being restored, conditions still are not totally under control

Integrated quality assessment of sediments from harbour areas in Santos-São Vicente Estuarine System, Southern Brazil

Santos-São Vicente Estuarine System is a highly populated coastal zone in Brazil and where it is located the major port of Latin America. Historically, port activities, industrial and domestic effluents discharges have constituted the main sources of contaminants to estuarine system. This study aimed to assess the recent status of sediment quality from 5 zones of Port of Santos by applying a lines-of-evidence approach through integrating results of: (1) acute toxicity of whole sediment and chronic toxicity of liquid phases; (2) grain size, organic matter, organic carbon, nitrogen, phosphorus, trace metals, polycyclic aromatic hydrocarbons, linear alkylbenzenes and butyltins; (3) benthic community descriptors. Results revealed a gradient of increasing contamination for metals and organic compounds, alongside with their geochemical carriers. Sediment liquid phases were more toxic compared to whole sediment. Low number of species and individuals indicated the impoverishment of benthic community. The use of sitespecific sediment quality guidelines was more appropriate to predict sediment toxicity. The integration of results through Sediment Quality Triad approach and principal component analysis allowed observing the effects of natural stressors and dredging on sediment quality and benthic distribution. Even with recent governmental efforts to control, pollution is still relevant in Port of Santos and a threat to local ecosystems