Effect of Cadmium-contaminated Brown Rice Diet on Accumulation of Heavy Metal in Rats

Movement and accumulation of cadmium in male Sprague-Dawley rats, fed with brown rice from nearby Janghang smeltery area were investigated. The rat fed with five different cadmium level diets made with Cd-polluted during 12 weeks. The brown rice-polluted with 0.87 ppm Cd (PBR) was sampled from products in the Janghang smeltery area. Diets of brown rice group were brown rice (BR, 0.002 ppm Cd), each 50% of BR and PBR (BR+PBR 50%, 0.44 ppm Cd) and PBR (PBR 100%, 0.87 ppm Cd). To compare with BR+PBR 50%, the another group diet composed the feed (FE, 0.002 Cd ppm) and each 50% of FE and PBR (FE+PBR 50%, 0.44 ppm Cd). Accumulation of Cd, Zn and Cu in blood, liver and kidney rats was measured by GF-AAS. The weight gain in BR groups and FE groups were different 0.22-0.26 and 1.08-1.26 g/day, respectively. Daily intake cadmium was 10.77 and 22.36 ㎍/rat in BR+PBR 50% and PBR 100%, and 8.83 ㎍/rat in FE+PBR 50%. Cadmium contents in diets were higher, and total intake of the heavy metals was more increased on the whole. Weights of liver and kidney in FE+PBR 50% group was 2.64 and 2.27 folds higher than those in BR+PBR 50% group. Cadmium contents in blood were increased with intake of BR diet, but Zn and Cu were decreased with them. In the diet groups with the same Cd concentration, Cd content of FE+PBR 50% was higher 1.27 times than that of BR+PBR 50%. In the diet group of BR, BR+PBR 50%, and PBR 100%, the increase of Cd concentration was significantly different to the increase of Cd content in the livers. In the same condition of Cd concentration, Cd contents were higher in the BR+PBR 50% group. In the diet groups of BR, BR+PBR 50%, and PBR 100%, the increase of Cd content in the kidneys led to the increase of Zn and Cu contents. In the same condition of Cd concentration, the diet group with the addition of BR was shown to be 3.11 times higher than with the addition of FE. In view of the results so far achieved, It was closely related with Cd, Zn, and Cu content.