A technique to quantify surface adsorption of heavy metals by soft-bodied invertebrates

Abstract 1. 1. The technique, described with reference to 65 Zn uptake by Tubifex tubifex , is based on immersion of experimental animals in iminodiacetic acid (IDA) coupled to Epoxy-activated (EA) Sepharose 6B (40–100 μm diameter) to chelate exclusively surface-associated heavy metals. Comparative data on metal levels removed by chelation and retained by the organisms allow quantification of surface adsorption. 2. 2. Surface extraction of pre-incubated (200 μCi/l 65 Zn; 5 min) T. tubifex by EA-Sepharose 6B-IDA showed that approx 90% of accumulated 65 Zn was surface adsorbed. 3. 3. Optimal extraction time was 1 hr; extraction pH was not critical. 4. 4. Applications of the technique are discussed.