Evaluation of the influence of humic substances on As(III) and As(V) toxicity by bioassays with Artemia salina
Detalhes
- Tipo de apresentação: Sessão Coordenada PG - Pós Graduando
- Eixo temático: Química Ambiental - AMB
- Palavras chaves: Arsenic; Crustaceous; Inorganic; Toxicology;
- 1 UFAL
- 2 Universidade Federal de Alagoas
Evaluation of the influence of humic substances on As(III) and As(V) toxicity by bioassays with Artemia salina
Aryanna Sany Pinto Nogueira Costa
UFAL
Resumo
Natural and anthropogenic activities are increasing the concentration of arsenic (As) species in the environment so that, according to the Agency for Toxic Substances and Disease Registry (ATSDR), this element is at the top of the priority list of potentially toxic substances1 . Considering the evident interaction between As species and humic substances (HS) that can alter the characteristics of As species in the natural environment2 , this work aimed to evaluate the influence of humic substances (HS) on As(III) and As(V) toxicity to the microcrustacean Artemia salina. The experiments were performed in 10 mL test tubes containing 10 model organisms in the larval phase, under different concentrations of As(III) or As(V) standard solution (0.5 - 20 mg L-1 ), and fixed HS concentration (10 mg L-1 ). After times of 24, 48 and 72 h, the number of live larvae was checked by manual counting using a Pasteur pipette. For both As assays the control assay was performed. Afterwards, the effect of HS was evaluated, varying concentrations in 10, 20, and 40 mg L -1 , as well as the concentrations of As(III) standard solution, in a fixed time of 72 h. All experiments were performed in quadruplicate. According to the obtained results, the presence of HS in the Artemia salina cultures caused a reduction in the toxicity of the arsenic species to the microcrustacean, since the lethal concentration (LC50) was increased (Fig 1). For As(III), this difference was only verified significantly after 48 h of exposure, while for As(V) there was a difference in the first 24 h. Finally, it was verified that the presence of HS promotes a positive effect to systems containing Artemia salina due to the reduction of the toxicity of the evaluated As species due to the As-HS complexation. Thus, it can be inferred that the interaction between humic substances and As(III) and As(V) present in aquatic environments, positively influences this type of environment.
Discussões Científicas de Qualidade
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Aryanna Sany Pinto Nogueira Costa
Muito obrigada, Maria Célia!
Não posso te afirmar que há uma relação direta entre o LC50, referente a toxicidade das espécies de arsênio avaliadas (As(III) e As(V)), com nós humanos. No entanto, essas espécies de As são as principais, dentre as existentes, no ambiente aquático. E como risco subsequente, estas são as formas mais tóxicas e são bioacumuláveis por muitos frutos do mar e diferentes tipos de peixes, sendo estes, vastamente consumidos por pessoas de diferentes regiões que dispõem desses organismos. Cito aqui como exemplo o camarão (organismo modelo utilizado no presente estudo, sendo na sua fase larval), sururu, massunim, peixes, dentre outros. Assim, ao constatar que um determinado efeito, como no caso das SH, a toxicidade dessas espécies é diminuída, consequentemente, tanto o ambiente quanto o homem estão menos expostos aos riscos inerentes a sua toxicidade.
Espero ter respondido, mas caso não tenha ficado claro, estou à disposição, tá!?
Abraços,