Data/hora: 31/05/2024 04:37:48

Biblioteca(s): | Embrapa Pantanal.
Data corrente: | 12/07/1999
Data da última atualização: | 05/07/2018
Autoria: | NUNES, V. da S.
Afiliação: | VÂNIA DA SILVA NUNES, CPAP.
Título: | The biodegradation and toxicity of aromatic and halogenated aliphatic hydrocarbons.
Ano de publicação: | 1996
Fonte/Imprenta: | Las Cruces, New Mexico: New Mexico State University, 1996.
Páginas: | 125 p.il.
Idioma: | Inglês
Notas: | Ph.D. Thesis.
Conteúdo: | Three hypotheses were tested in this study relating microbial biodegradation activity to changes in toxicological properties. The hypotheses were 1) The biodegradability of a given pollutant in a binary pollutant sample may be different from its biodegradability alone, because there might be a synergistic or antagonistic effect between the pollutants since different classes of pollutants have different degradation pathways and may have different effects on the biodegrading microbes; 2) Using a Ceriodaphnia dubia toxicity bioassay, the toxicity of a given pollutant in a binary pollutant sample may be different from its toxicity alone, bacause of concentration addition, synergism or antagonism effects; 3) The toxicity of the biodegradation products is different from that of the parent pollutant because biodegradation reactions break intramolecular bonds of organic pollutants, changing their properties. In most cases, biodegradation of both benzene and toluene occurred within the first week, though toluene biodegradation was more consistent. Benzene exerted and antagonistic effect on the degradation of toluene, because toluene degraded faster when alone than in the presence of benzene. The presence of chloroform or toluene did not exert any effect on benzene degradation. Similar compounds at the same concentration (i.e., benzene 10 ppm and toluene 10 ppm) had an additive toxicity interaction effect on C. dubia. That is, the combined toxicity effect of both was equal to the sum of the effect of each alone. Toluene was more toxic than benzene. Dissimilar compounds at the same concentration (i.e., benzene 10 ppm and chloroform 10 ppm) also had an additive toxicity interaction effect and benzene and chloroform had similar toxicities. The toxicity to toluene was significantly reduced after toluene degradation. The percentage of dead C. dubia for toluene treatments was 88% before biodegradation and 33% afterwards. On the other hand, the percentage of dead C. dubia for benzene was 33% before biodegradation and 24% afterwards. Thus, toxicity decreased only slightly after biodegradation in the case of benzene. In both cases, residual toxicity after biodegradation was presente. I suggest that bioremediation technologies incorporate routinely the use of bioassays for contaminated site clean-up.
Palavras-Chave: | Benzeno; Cloroformio; Tolueno.
Thesagro: | Biodegradação; Ecologia; Poluente; Toxicologia.
Thesaurus Nal: | benzene; biodegradation; chloroform; ecology; pollutants; toluene; toxicology.
Categoria do assunto: | --
Registro original: | Embrapa Pantanal (CPAP)
Exemplares: | CPAP - (40588-1) - UPC - TS - PP - TS99.00016 - o-808 - 1999.00016 - DIS