Accumulation of trifluralin and trinitrotoluene (TNT) in two aquatic invertebrates: formation and persistence of unextractable biotransformation products.

Abstract

Exposure to nitroaromatic compounds has been reported to result in unextractable residues, or residues not readily extracted by traditional techniques. However, limited information is available about the formation rate and biological half-life of unextractable residues in aquatic organisms. In this study, two aquatic invertebrates, Lumbriculus variegatus and Hyalella azteca, were exposed inaqueous media to ¹⁴C-labeled trinitrotoluene and trifluralin. Unextractable residues were formed in both organisms by both compounds. TNT formed a greater percentage of unextractable residues than trifluralin. L. variegatus accumulated more TNT-related unextractable residues compared to H. azteca, while the reverse was true for trifluralin. H. azteca eliminated unextractable residues moreefficiently than L. variegatus. Additionally, the biological half-life of unextractable residues was longer than that of the extractable residues. The presence and biological persistence of unextractable residues indicates that these compounds, and especially TNT, could cause subtle and chronic biological effectsand serve as indicators of exposure.