Residue dynamics and effects of aluminum on growth and mortality in brook trout

Abstract

AbstractBrook trout (Salvelinus fontinalis) about 30 d old and weighing 0.2 g were exposed for 56 d to duplicated nominal pHs of 5.0, 6.0 and 7.2 in combination with nominal aluminum concentrations of 200 μ/L. At 56 d, each treatment group was transferred to water of the same pH without added aluminum and held for 28 d of depuration. Samples of fish were collected from each treatment for whole‐body aluminum analyses on days 3, 7, 14, 28 and 56 of the exposure. During the depuration period, fish were sampled at 3, 7, 14 and 28 d for whole‐body aluminum analyses. Mortality and pH were monitored daily in each treatment. The estimated time to 90% steady state for aluminum in the fish was 1.5 d at pH 5.3, 4.2 d at pH 6.1 and 1.7 d at pH 7.2. Estimated steady‐state bioconcentration factors for aluminum, which were inversely related to pH, were 215 at pH 5.3, 123 at pH 6.1 and 36 at pH 7.2. The maximum observed factors were 232 at pH 5.3, 153 at pH 6.1 and 46 at pH 7.2. Brook trout eliminated aluminum from tissues more rapidly at pH 5.3 than at pH 6.1 and 7.2. Mortality was generally higher in brook trout exposed to aluminum at pH 5.3 than in those exposed at pH 6.1 and 7.2. Mortality was lowest (<3%) for the fish exposed to aluminum at pH 7.2.