Meinertz, J.R., S.L. Greseth, G.R. Stehly, and W.H. Gingerich. 2002. Depletion of para-
toluenesulfonamide from the edible fillet tissue of yellow perch after exposure to 
chloramine-T. Final report submitted to the UMESC archives February 27, 2002 and 
submitted to the Center for Veterinary Medicine, U.S. Food and Drug Administration, 
February 27, 2002. 1402 pages.
Summary
Waterborne exposure to chloramine-T is an effective treatment for controlling fish 
mortalities caused by bacterial gill disease. Currently, data are being generated to gain 
U.S. Food and Drug Administration (FDA) approval for the use of chloramine-T in 
aquaculture. As part of the data required for an approval, depletion of the chloramine-T 
marker residue (para-toluenesulfonamide; p-TSA) from the edible fillet tissue of exposed 
fish must be determined. Yellow perch (Perca flavescens; mean weight 144.1 g) were 
exposed to 20 mg/L of chloramine-T for 60 min on four consecutive days in water at 15 
°C (the most aggressive treatment expected for the label). Groups of fish (n = 15 or 16) 
were sampled immediately after the last treatment, and at 3, 12, 24, 48, 96, and 168 hours 
after the last treatment. Duplicate subsamples of skin-on fillet tissue from each fish were 
analyzed with a proposed determinative high performance liquid chromatography 
(HPLC) method for p-TSA in fish fillet tissue. The mean concentration of p-TSA in fillet 
tissue from fish sampled immediately after the last treatment (0 h sample group) was 150 
ng/g, 15 % of the probable 1000 ng/g tolerance limit for p-TSA in fish fillet tissue; p-
TSA concentrations in individual fish from the 0 h group ranged from 73.3 to 200 ng/g. 
One hundred sixty eight hours after the last treatment, the mean concentration of p-TSA 
was 35 ng/g; p-TSA concentrations in individual fish from the 168 h sample group 
ranged from 9 to 82.6 ng/g.