Avaliação do efeito toxicológico de Atrazina na retina de alevinos de Collossoma macropomum (Cuvier,1818)
Resumo
Atrazine is a herbicide that has physical-chemical characteristics that increase the
chance of reaching groundwater. Among the most commercially available active ingredients in
Brazil, atrazine ranked 3rd in the ranking in 2013 and is considered very toxic to aquatic
organisms. Aims of this research was to evaluate the toxicological effect of atrazine on the
retina of Colossoma macropomum fingerlings. Acute toxicity tests (5, 15, 30, 45 and 60 mg/L)
were performed using the Trimmed Spearman-Karber method. In the chronic tests, the
fingerlings were exposed to the following concentrations: 0.85, 4.2, 8.3 and 16.5 mg/L, and the
retinal samples were then submitted to histological analysis and stained by the HE method. The
LC5096h of atrazine for tambaqui fingerlings was 27.78 mg/L, with a lower limit of 22.49 mg/L
and an upper limit of 34.22 mg/L, and the CENO concentration was 5 mg/L and the CEO was
the concentration of 15 mg/L. In the chronic test, the morphological parameters of the cellular
layers of the retina of the fingerlings were evaluated, which did not suffer any alterations
between treatments. On the other hand, the literature points to the neurotoxic consequences of
the exposure of fish species to acute and / or subacute concentrations of atrazine. We can base
this assertion on the reported toxicity findings that bear references of behavioral changes by its
authors, verified against the different concentrations of this compound, such as deviations from
standard behaviors described as: irregular swimming, lethargy, accelerated water surface
respiration, which were also observed during the present study. In addition, the results of water
samples analyzed did not show sharp changes in values between treatments, both acute and
chronic.
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