Uptake, toxicity, and effects on detoxication enzymes of atrazine and trifluoroacetate in embryos of zebrafish

The uptake, toxicity, and elimination of atrazine and trifluoroacetate (TFA ) were studied in early life stages of the zebrafish (Danio rerio). Further more, the effects of these xenobiotics on soluble (s) and microsomal (m) gl utathione S-transferases (GST) of zebrafish embryos were investigated using 1-chloro-2,4-dinitrobenzene (CDNB), 1,2-dichloro-4-nitrobenzene (DCNB), an d [C-14]atrazine. [C-14]Atrazine was taken up by the embryos within seconds , unhindered by the chorions. It accumulated in the embryos by a factor of 19 after 24 h of exposure time. LC50, (48 h) was determined at 36.8 mg/L. A t a level of 5 mg/L atrazine, activities of s and m GSTs,were elevated in m ost stages, especially in prim 6 and long pec stage (24, 48 h after fertili zation, respectively). GST activity toward atrazine was detectable only in untreated D. rerio eggs, increasing with developmental time. [C-14]Atrazine was eliminated from the embryos between 24 and 48 h, indicating a possible metabolism to a more hydrophilic GSH conjugate. [C-14]TFA was taken up by embryos, reaching at maximum fivefold the concentration of the incubation m edium after 10 h. The chorions served no physiological protection. TFA (1 g /L) caused low elevation of the GST activity. No acute toxic effects (48 h) were observed up to 4 g/L TFA. (C) 2000 Academic Press.