Cytogenotoxicity of SPL "(Spent Pot Liner" by plant root tip bioassays. / Citogenotoxidade do SPL (Spent Pot Liner) por meio de bioensaios vegetais em Ãpice radicular.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

SPL (Spent Pot Liner) is a toxic solid waste generated by aluminum industry during the manufacturing of aluminum metal in electrolytic cells. It has a composition highly variable including fluoride salts, cyanides, metals and organic compounds. In Brazil, aluminum industries generate about 35,000 t of SPL per year. Some industries recycle this waste as feedstock in other industries, i.e. cement industries. However, information on the cytotoxicity of SPL is necessary to facilitate the understanding of its action on organisms in the environment and to subsidize environmentally correct solutions. The use of plants to measure potential environmental risk has been recognized as excellent to detect a wide range of genetic alterations under genotoxic contamination in the environment and a lot of chemicals elements were tested. Thus, methodologies that evidence DNA damage, alterations in cell structures and root meristem are important tools for these studies of cytotoxicity on organism. In addition, roots are frequently used on bioassays because they are first exposed to chemicals or wastes dumped on soil or water. The aim of the present work was to evaluate the citogenotoxicity of SPL in plant bioassays. The results showed the toxic effects of SPL by the increase in frequency of chromosome abnormalities, inhibition on root growth and induction of cell death in SPL-treated root tips. Moreover, it was observed among the plant tests a relation between the increases of SPL concentrations and incease on percentage of cells with alterations (anaphase/telophase bridges, stickness, fragments and c-metaphasis) and also the reduction on root growth. By evaluating the effects of different SPL concentrations in different time of exposure, was observed a concentration-exposure-depend manner in relation to cell death features. TUNEL (Terminal deoxynucleotide transferase mediated-dUTP nick-end labeling) assay, ladder pattern of DNA fragmentation, changes in nucleo-plasmic ratio and increase on antioxidants enzyme activity due to oxidative stress caused by SPL treatment were observed. SPL also provoked damage in root tips surface. Nevertheless, post-exposure root in distilled water demonstrated that SPL damage may be reversible after lower exposure times. It is obvious from the results that SPL is a toxic waste and solutions are necessary to solve the problem of SPL that is still dumped on the environment.

ASSUNTO(S)

citologia vegetal

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