Whole-body distribution and Malpighian tubule transport of 2′,5-dichloro-4′-nitrosalicylanilide (Bayer 73) and 3-trifluoromethyl-4-nitrophenol in larvae of the aquatic midge Chironomus tentans

Abstract

1. Residues of the lampricides ¹⁴C-Bayer 73 (2′,5-dichloro-4′-nitrosalicylanilide) and ¹⁴C-TFM (3-trifluoromethyl-4-nitrophenol) were absorbed from aqueous sublethal concn. by aquatic larvae of the midge Chironomus tentans.

2. Toxicant residues were widely distributed during early hours of exposure, but later and during a 24-h post-exposure period, they became concentrated in the trunk and intestinal tract; the posterior movement of Bayer 73 was more rapid than that of TFM.

3. During 4-h tests, Malpighian tubules of the chironomid actively transported Bayer 73 and TFM in vitro, and on a per tubule basis, more TFM was transported than Bayer 73.

4. Potassium cyanide inhibited tubule transport; serotonin had no effect.