Pilot trials with a fluorescent whitening agent of the bis(triazoly) stilbene-disulfonic acid type in golden orfes.

Golden orfes were examined for uptake, distribution, and elimination of radioactivity administered in the form of a 14C-labelled fluorescent whitening agent (FWA) of the bis(triazolyl)stilbenedisulfonic acid type. Results of these studies are given below. Pilot trials using FWA concentrations of 10 and 100 ppb and a population density of 1 fish per liter show that an equilibrium between uptake and elimination of the FWA develops in the animals within a period of one week; i.e., the incorporated traces of the FWA are not irreversibly bound. The radioactivity is mainly located in the gall bladder and in the intestinal contents, as well as in the liver, throat, and gills. The muscular system (filet) is virtually free from activity. Approximately 1-2% of the FWA amount administered per animal (corresponding to the concentration factors of 7-14) can be temporarily detected in the fish. Radioactivity is eliminated comparatively quickly. Two days following the transfer of the fish into water free from FWA a concentration factor as low as 1 is reached, i.e. from this time the FWA concentration in the animals decreases to less than 10 resp. 100 ppb.