BRESOLIN, J. D.

FERREIRA, L. R.

GOUVEA, S. P.

ROSOLINO, R. M.

SILVA, W. T. L. da

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Ecotoxicological assessment of waste treatment of acid 3.5 dinitrosalicylic by photodegradation.

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/I//Fórum InternacionalA Sustentabilidadeno Século XXIMEIO AMBIENTE E SAÚDE EM DEBATEECOTOXICOLOGICAL ASSESSMENT OF WASTE TREATMENT OF ACID 3.5 DINITROSALlCYLlC BYPHOTODEGRADATIONLeandro Rosa Ferreira*; Rodrigo Mattiazo Rosolino; Wilson Tadeu Lopes da Silva; Sandra Protter Gouvêa; Joana Dias Bresolin*Aluno de graduação em Química, Universidade Federal de São Carlos, São Carlos, SP; leandro.rosa@live.ca3.5 Oinitrosalicylic acid (ONS or ONSA with formula C7H4N207) is an aromatic compound used in carbohydrates andenzyme assays. The aromatic ring in the structure makes their residue unsuitable for sewage disposal. Given the largevolume ofwaste generated during analysis using ONS and the irnpltcation ofits disposal, we propose a treatment througha photoreactor system (photolysis process) and an ecotoxicity assessment ofwastes before and after this treatment. Theecotoxicity test proposed has terms based on the standard OEC0201 (2006) and seeks to assess the toxic effects on amicroalgae commonly found on water resources in the region, Pseudokirchneriella subcapitata (Chlorophyta), assistingin the evaluation of maximum concentrations for a safe disposal. The residue produced was assessed after quantificationof carbohydrate activities in the Bioenergy Laboratory at Embrapa Agriculturallnstrumentation (CNPOIA). The treatmentof this waste by the process of photolysis used hydrogen peroxide at 30% in proportional volume to 2% of total volume.The system was kept at continuous recirculation for five hours by performing scans in the UV-visible spectrometer (600-200 nm) before, during and after the period of photolysis. Ultraviolet radiation provided by the lamps in system favors thephotolysis of hydrogen peroxide, resulting in hydroxyl radical that reacts with the aromatic ring present in the molecularstructure of the ONS. On the scan performed at baseline (O hours), we observed a peak absorbance at a wavelengthbetween 250-300 nm, characteristic of aromatic compounds. The scan performed at the end of treatment (5 hours)showed considerable decrease in absorbance (from 0.386 to 0.127). The photodegradation of the residue was alsoobserved by its color, changed from an intense orange to yellow at the end of processo Thus, the treatment was effective,as there was disruption of the connections of the aromatic ring structure in the residue. In addition to treatment, theecotoxicity test aimed to evaluate the rate of growth inhibition of a microalgae exposed to five different wasteconcentrations (treated and untreated) and a substance of known toxicity. The ecotoxicity test showed significantdifferences in growth inhibition when testing the residue before and after treatment. The sample with concentration of 0,81ml/L of residue showed inhibition rate of 11,85% when untreated, while the treated sample showed 2,25% inhibition.Apparently the residue after treatment shows less inhibition of algal growth, which indicates a less toxic nature whichmeets the pattern observed in the UV-visible. Nevertheless, none of the tested concentrations approached the EC50, i.e.50% inhibition of algal growth. Thus, other concentrations will be tested in order to assist in determining concentrations forsafe disposal, even after treatment. Since it was not found in the literature treatment or safe disposal guidelines for thiswaste, this work becomes the first step to creating a standard protocol for ONS treatment and disposal. The authors thankOr. Armando Augusto Vieira and technologist Antonio Luiz Sartori of the Botany Oepartment / UFSCar, for providing thestrain used in the study and Or. Cristiane Farinas for providing the waste.Realização:UFPel::)www.utpet.edu.br

Ecotoxicological assessment of waste treatment of acid 3.5 dinitrosalicylic by photodegradation.

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