Predicting Bioavailability Of Cd²⁺ Ion To Rhodeinae By Diffusive Gradient In Thin-Film Technique

Heavy metals pollution is a growing problem in the world today;it can seep through the environment and into the food chain affecting both animals and humans alike.Recent studies have shown that not all heavy metals can be absorbed by animals.The mass absorbed by animals depends on species of metal.The species can be bio-available or not bio-available.The bio-available part of the species is the one that needs to be determined.There are several methods to determine the bioavailable concentration,and diffusive gradients in thin-film technique(DGT)is one of them.In this work,CMC-DGT was established by using Carboxymethylcellulose sodium(CMC)as binding phase and cellulose acetate dialysis membrane as diffusive layer.The concentration of CMC for binding phase of CMC-DGT was optimized.The optimized concentration was 0.015mol/L.The diffusive coefficient of cadmium ions across through the dialysis membrane was measured as 1.097x10-6cm2/s.The Effect of free Cd ion concentration on the masses accumulated by CMC-DGT and fish was assessed and the masses accumulated by fish gills,fish body and CMC-DGT were increased with increasing concentration of Cd.The trend of masses accumulated by CMC-DGT,fish gills and fish body are similar.In the same period,the mass accumulated by fish gills is much more than that by fish body.The correlations between CMC-DGT and fish gills and fish body were obtained.The correlation showed a quantitative equation for both fish gills and fish body and CMC-DGT.Fish gills(y1)and CMC-DGT(x1):y1=3.8014x1+72.65 R2=0.7444,and fish body(y2)and CMC,DGT(x2):y2=0.3179x2+7.6442 R2=0.6562.The CMC-DGT has the potential to predict bioavailability of Cd to Rhodeinae.