(PH034) Bioaccumulation and toxicity and of 14C-TNT to marine fish.
Blackburn, W.1, Fleeger, J.2, Lotufo, G.2, 1 Jackson State University, Department of Biology, Jackson, MS, USA2 Louisiana State University, Department of Biology, Baton Rouge, LA, USA
ABSTRACT- The bioaccumulation and toxicity of trinitrotoluene (TNT) to adult freckled blennies (Hypsoblennius iontha) and juvenile sheepshead minnows (Cyprinodon variegatus) were investigated in exposures to spiked sediments. Adult blennies collected from coastal Louisiana were exposed to spiked sediments (30, 100, 300 mg/kg) for 1 and 7 days. TNT completely degraded to aminonitrotoluenes during the 20-d storage period and 20 to 60% of the amount spiked partitioned into the overlying water (not renewed) during the exposure. Degradation was substantially faster in the lowest treatments. No TNT-related mortality occurred. Fish bioaccumulated aminonitrotoluenes at detectable levels only in the highest treatment. Bioconcentration factors determined using overlying water concentration and body burden at experiment termination were similar to those determined from aqueous exposures to aminonitrotoluenes suggesting that uptake form overlying water is the major source of bioaccumulation of TNT-related compounds in fish under static exposure conditions. Therefore, renewal of overlying water or flow-through conditions would likely result in fast depletion of compounds from the exposure system and negligible bioaccumulation of TNT-related compounds in fish. Experiments using juvenile minnows were conducted to confirm the apparent low relative importance of direct contact with sediment as a source of uptake of TNT-related compounds by using isolation from sediment via meshed screen as an experimental treatment. To investigate the potential for bioaccumulation of TNT in fish from breached artillery rounds, exposures were conducted using TNT chunks partly buried in fine-grained or sandy sediments and juvenile minnows. TNT dissolution rats, partitioning into surrounding sediment, degradation and whole-body bioaccumulation in fish were investigated. Results from the experiments using minnows will be presented and compared to the blennie experiments.
Key words: Cyprinodon variegatus, TNT, bioaccumulation, sediment