Maria Teresa Raya-Rodriguez

Adsorção em carvão ativado em pó para remoção de microcistina de água de abastecimento público

A ocorrencia de floracoes de cianobacterias em mananciais de abastecimento publico prejudica a qualidade da agua, podendo, inclusive, ocasionar a presenca de cianotoxinas. A dificuldade de remover as cianotoxinas da agua motivou o presente trabalho, cujo objetivo foi o de avaliar a remocao da cianotoxina microcistina empregando diferentes carvoes ativados em po (CAPs). Os CAPs foram caracterizados quanto ao numero de iodo, granulometria, distribuicao e volume de poros, alem das isotermas de Freundlich. Os resultados mostraram que os CAPs de madeira apresentaram os maiores valores do numero de iodo, capacidade maxima adsortiva (qe, max) e volume de microporos secundarios e mesoporos. A adequada caracterizacao do CAP e uma etapa importante na sua aquisicao pelas estacoes de tratamento de agua, pois indices isolados podem nao avaliar corretamente o CAP.

Assessment of the freshwater annual fish Cynopoecilus melanotaenia as a toxicity test organism using three reference substances.

This study presents a preliminary evaluation of the use of the Brazilian fish Cynopoecilus melanotaenia as a test organism in toxicity tests. The cryptobiotic stage presented by the eggs of fish C. melanotaenia can overcome the difficulty of continuously keeping cultures and recruiting healthy animals in sufficient numbers to be used in toxicity tests. In order to determine the applicability of this species as a test organism, three different reference substances were evaluated in 96-h acute toxicity tests: Copper sulfate (CuSO4 x 5H2O), sodium dodecil sulfate (C12H25NaO4S), and sodium chloride (NaCl). Sensitivity ranged as follows: copper sulfate (0.05-0.13 mg/L), sodium dodecil sulfate (10.7-19.0 mg/L), and sodium chloride (1.44-1.96 g/L). We conclude that C. melanotaenia shows potential as a test organism in toxicity tests; however, further research should be conducted with other substances and should be compared with the research on other species before we can reach more conclusive results.

Diagnóstico da qualidade analítica na quantificação de cianobactérias

The increase of cyanobacterial blooms in water sources used for supply is a global concern. Following the guidelines of the World Health Organization, ordinance no 518/2004, the of the Ministry of Health, provides the monitoring of cyanobacteria in superficial water sources and, when appropriate, in treated water. In Brazil, there is no standardization of analysis methods; thus, the applied methods should provide reliable results. Through voluntary participation, a proficiency testing program in cyanobacteria was conducted in 2010. This paper presents the diagnostic performance of laboratories in identification and counting of cyanobacteria. Results of counts were subjected to the calculation of z-score, and 80% of laboratories presented satisfactory performance. Differences were observed in the identification of cyanobacterial genera.