POLYMER-LIGANDS - A NOVEL CHEMICAL-DEVICE FOR MONITORING HEAVY-METALSIN THE AQUATIC ENVIRONMENTS

Major problems involved in using bio-indicators to monitor heavy metal s in the marine environment include standardizing a great variety of p hysical and biological factors which have a significant effect on meta l accumulation. The fact that different species may have different acc umulation strategies for different metals, and also that the natural d istribution of indicator species is limited, often prevents comparison between monitoring results in different geographic areas and hydrogra phic conditions. Furthermore, environmental effects on the uptake and depuration of the metals in the biological indicators are not well und erstood. In the present study, uptake of Cd, Pb and Zn by four polymer -ligands (i.e. Chelex(R) 100, Poly(4-vinylpyridine), Sephadex Sp C-25 and Amberlite IR-122) were studied. Laboratory results showed that Che lex(R) 100 was most effective in taking up the soluble fractions of th ese three metals at low ambient concentrations (0.1-10 mg l(-1)). Equi librium at low concentrations was reached in about 21 days. Concentrat ion factors after 21 days exposure ranged from 2500 to 5500, depending upon the metal species and ambient concentration. Both uptake and rel ease of metals by Chelex are directly responsive to ambient concentrat ions and exposure time. Results of field transplantation of Chelex and mussels (Perna virvidis) also showed that Chelex accumulated signific antly higher levels of Cd, Cr and Pb, similar levels of Cu, and a lowe r level of Zn than those of mussels under natural field conditions. Co efficients of variations of metal uptake were also much smaller with C helex. The suitability of using Chelex(R) 100 as a novel chemical devi ce for monitoring metal pollution in the aquatic environment is evalua ted against selection criteria established for metal bioindicators. (C ) 1996 Elsevier Science Ltd