Toxicity and bioaccumulation of TNT in marine fish in sediment exposures

The bioaccumulation potential and toxicity of 2,4,6-trinitrotoluene (TNT) spiked to sediment was evaluated in juvenile sheepshead minnows (JSHM, Cyprinodon variegatus) and adult freckled blennies (FB, Hypsoblennius ionthas). The JSHM were exposed for 4 days in the presence or absence of a mesh separating fish from sediment. FB were exposed to sediment for 7 days. During the 24-day storage period (4 °C), extensive transformation of spiked TNT occurred and concentrations are expressed as the sum of TNT, aminodinitrotoluenes and diaminonitrotoluenes (SumTNT), on a dry weight basis. SumTNT in the overlying water, not exchanged during exposure, increased gradually. Survival was high (≥90%) for JSHM exposed to 7 mg kg−1 and FB exposed to up to 260 mg kg−1. All SHM died after 24 h exposure to 340 mg kg−1. Isolation from sediment did not significantly affect water concentrations or decrease bioaccumulation. Uptake from contact to sediment was likely negligible and bioaccumulation was from the overlying water. The feeding rate of FB exposed to 1700 μmol kg−1 sediment suspended in water for 24-h was significantly reduced by 50%.