Meinertz, J.R., S.L. Greseth, C. Vue, G.R. Stehly, and W.H. Gingerich. 2002. Depletion 
of para-Toluenesulfonamide from the Edible Fillet Tissue of Hybrid Striped Bass 
(Morone saxatilis x M. chrysops) 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, March 1, 2002. 881 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. Hybrid striped bass (Morone saxatilis x M. chrysops; mean 
weight 356.9 g) were exposed to 20 mg/L of chloramine-T for 60 min on four 
consecutive days (the most aggressive treatment expected for the label) in water at 15 °C. 
Groups of fish (n = 16) were sampled immediately after the last treatment, and at 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 high performance liquid chromatography (LC) 
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 142 ng/g 
(14 % of the probable 1000 ng/g tolerance limit for p-TSA in fish fillet tissue) with 
concentrations in individual fish ranging from 104 to 200 ng/g. One hundred sixty-eight 
hours after the last treatment, the mean concentration of p-TSA was 94 ng/g with 
concentrations in individual fish ranging from 75 to 109 ng/g.