To investigate the cadmium (Cd) toxicity on the testis, male rats were treated with 1, 2, 4 and 8 mg/kg of Cd by IP. According to histochemical studies, Cd-treated testis tissue showed death of spermatozoa, death of Sertoli cells, death of all the spermatogenic cells, and finally disappearance of basal lamina of seminiferous tubules with increasing doses, and showed decreased ground substances and Leydig cells, increased inflammatory cells and fibroblasts, and fibroblasts, and finally disappearance of ground substances and all the cells except fibroblasts within interstitial tissues with increasing doses. According to biochemical studies, two kinds of proteins, 25 and 45 kDa, were dramatically disappeared from the total protein of rat testis treated with Cd comparing to normal testis. The result of electrophoresis of total protein suggests that actin (45 kDa), presumed on its mmolecular weight and amount, in the testis-cells is the primary target of Cd poisoning. Although its exact mechanism is not clear, the disappearance of two proteins when testis is exposed to Cd should give some clues to understnad the mechanism of necrosis of testis tissue crumbling by heavy metal pollutant such as Cd.

Mercury- and cadmium-resistant bacteria were isolated from an industrial complex wastewater of Taejon area. All of them were motile, gram negative rods. In the results of physicochemical test and VITEK card test, HMI was identified with Acinetobacter calcoaceticus, CM3 was identified with Comamonas acidovorans, HM2, HM3, CM1, and CM4 were Pseudomonas sp., but HM4 and CM2 were unidentified. They were tested for susceptibility to 14 heavy metals. Mercury-resistant bacteria(HM1, HM2, HM3, and HM4) were sensitive to low concentration(100∼400ppm) of Cd^2+, Co^2+, Zn^2+, and Ni^2+ while cadmium-resistant bacteria(CM1, CM2, CM3, and CM4) showed resistance up to the high concentration(600∼1,200ppm) of these metal ions. As a result of resistance spectrum test of mercury-resistant bacteria, HM1 was broad-spectrum strain, HM2, HM3, and HM4 were narrow-spectrum strains. Transmission electron microscopic examination of cell wall of HM1 culture grown with and without 100ppm of HgCl_2 showed remarkably morphological abnormalities. In the result of atomic absorption spectrometric analysis of cadmium-resistant bacteria grown at 200ppm of CdCl_2 for 6h, all of them accumulated cadmium(14ppm∼57ppm) in cell. In cadmium-resistant bacteria, CM1, CM2, and CM4 were spared from the inhibitory effect of Cd^2+ by the addition of Mn^2+, CM4 were also spared from the inhibitory effect of Cd^2+ by the addition of Mn^2+ as well as Zn^2+.

In order to investigate the effects of pH and organic matter content on cadmium adsorption and exchangeable cations desorption in soils, the adsorption isotherms of cadmium and the desorption isotherms of calcium and magnesium on four New Jersey soils at four pH values were plotted, and the cadmium partition coefficients (Kd) were also calculated. The slopes of cadmium adsorption isotherms dramatically increased with increasing solution pH. Judging from Langmuir adsorption equations, the maximum adsorption quantities (b) of cadmium at high pH values were much greater than those at low pH values for the same soil. The partition coefficients increased greatly with increasing solution pH. The slopes of regression equations between partition coefficients and pH values were steep in the order of the organic matter content of the soils. The correlation coefficients (r^2) between partition coefficient and organic matter content for 1 × 10 exp (-4) M increased from 0.3027 at pH 4.0 to 0.9964 at pH 8.5 and from 0.2093 at pH 4.0 to 0.9657 at pH 8.5 for 2×10 exp(-4) M Cd (NO3)2. The desorption quantities of calcium and magnesium decreased with increasing solution pH and increased with increasing cadmium adsorption.

Selective extraction procedure has been used to quantify copper and cadmium in association with the various phases of aquatic sediment such as exchangeable/adsorbed, carbonate, manganese oxides, organic matter and iron oxides. Changes of pH influenced on the partitioning of copper in carbonate and exchangeable/adsorbed phases and of cadmium in carbonate phase of aquatic sediment. Addition of NTA and EDTA, copper and cadmium associated with carbonate phase were released from sediment to water. Total partitioning coefficient was 8.361 for copper and 0.497 for cadmium. The relative binding strengths of copper and cadmium to each solid phase can be ranked by using the partitioning coefficints. For copper it was observed that carbonate > organic matter > exchangeable/adsorbed > manganese oxides > iron oxides and for cadmium it was observed that exchangeable/adsorbed > carbonate > manganese oxides > organic matter > iron oxides.

In order to predict the distribution of chemical species of copper and cadmium in water, conditional stability constant and complexation capacity between copper or cadmium and natural aquatic sediment have been determined in a shallow lake in Haman, Kyungnam. Kinetic parameters were calculated by Langmuir isotherm equation. Conditional stability constant was log K_cdses=4.78 and log K_cdsed=4.45. Complexation capacity was 1.70×10 exp (-4) moles/g for copper and 5.54×10 exp (-4) moles/g for cadmium. Accuracy of experimental values of conditional stability constant was checked by comparing the calculated concentration of the metals with the measured one. Relatively good agreement between these values was obtained. Relative errors were 8.9% for copper and 6.5% for cadmium. Data of the measured conditional stability constant were put into data base of MINEQL computer program, and concentration of various chemical species of copper and cadmium in a model aquatic system was calculated. Aquatic sediment was associated with copper at the concentration of 10^-5M(0.059g/ℓ) and with cadmium at the concentration of 10^-6M(0.018g/ℓ), and it significantly influenced on the distribution of chemical species of the metals. This result showed that prediction of chemical species of the heavy metals in an aquatic system should be taken into account the influence of the sediment.

Greenhouse pot experiments were conducted to evaluate the effects of lime, fly ash and ash(from rice straw) on the cadmium and lead translocation from soil to radish. The soils with low metal contents(Cd 1.52 ppm and Pb 25.37ppm) were prepared and high metal contents (Cd 8.99 ppm and Pb 50.81ppm) were prepared and amended with 0.25%, 0.5%, 1.0%, 2.0% each of lime, fly ash and ash. Radishes(Raphanus sativus) were cultivated and cropped on the soils during 25, 50 and 75 days after sprout, and then cadmium and lead contents of radishes were analyzed by roots and tops. The results obtained are as follows. 1. Lime and ash were effective in raising the soil pH, but fly ash was not effective. 2. The growth of radishes were not impaired by the cadmium and lead contamination but, impaired by soil pH 7.5 or more. 3. Cadmium was accumulated very strongly in radishes and the greater concentration was found in than roots, but lead showed no evidence of accumulation in radishes. 4. In general, when the concentrations of lime and ash in soils increased, the uptake of cadmium and lead by radishes decreased, and lime was more effective than ash, while fly ash revealed no effect of reducing the translocation of cadmium and lead from soils to radishes. 5. The uptake of cadmium by radishes decreased more effectively than lead and the uptake of Cd or Ph by radishes grown in the soils with high metal contents decreased more effectively than low metal con tents. 6. Cadmium and lead contents of radishes were negatively correlated with soil pH values and the relationship in cadmium content was stronger than that in lead content.