Cd-polluted Areas Research Articles

Urinary α1‐microglobulin as an indicator protein of renal tubular dysfunction caused by environmental cadmium exposure

An epidemiologic investigation was carried out to clarify the significance of the urinary excretion of alpha 1-microglobulin (alpha 1-MG) in people aged 50 years and over living in a Cd-polluted area in Japan. Approximately 80% of the population participated in the health examination. The urinary and serum levels and the relative clearance of alpha 1-MG to creatinine clearance were compared with various parameters (age, urinary beta 2-microglobulin (beta 2-MG), total protein, Cd, Cu and Zn, serum beta 2-MG, creatinine and blood urea nitrogen and relative clearances of alpha 1-MG, beta 2-MG, inorganic phosphate and uric acid). It was found that the urinary excretion of alpha 1-MG is closely associated with the urinary Cd and Cu and with the indices of renal dysfunction listed above. These results suggest that the urinary alpha 1-MG level markedly reflects a degree of proximal tubular dysfunction and that it may be useful as one of the screening measures for proximal tubular dysfunction caused by environmental Cd exposure.

Some metabolic interrelationships among cadmium, lead, copper and zinc: results from a field survey in CD-polluted areas in Japan. Part II. Fecal excretion of the heavy metals.

Some metabolic interrelationships among cadmium, lead, copper and zinc: results from a field survey in CD-polluted areas in Japan. Part II. Fecal excretion of the heavy metals.

Some metabolic interrelationships among cadmium, lead, copper and zinc: results from a field survey in CD-polluted areas in Japan. Part four: heavy metal ratios and correlations.

A series of analytical studies on heavy metal distributions in the foods, feces and urinary samples had been presented in this Journal. In the present paper, further statistical analyses on the interrelationship of each heavy metal were done with special reference to the heavy metal ratios and corre-lation coefficient matrices of these metals. Positive correlation coefficients between Cd and Cu in the fecal and urinary samples, which were observed among the inhabitants of Cd-polluted area, dissapeared among the inhabitants of the control area. This indicated the possible depression of Cu intake due to the higher dietary intake of Cd. At these levels of Pb intake observed in the both polluted and control area inhabitants, correlation coefficients of Pb to the other three metals among the former group showed similar values to those of the latter group. The ratios of all pairs of heavy metals in feces were similar to those ratios in rice and the other food samples, but different from those of the urinary metals. This suggests the different metabolism in human organs results the different excretion in the urine and in the feces.

Some metabolic interrelationships among cadmium, lead, copper and zinc: results from a field survey in CD-polluted areas in Japan. Part III. Urinary excretion of the heavy metals.

The four heavy metal concentrations (Cd, Pb, Cu and Zn) in the 216 urine samples from the residents of three Cd-polluted and matched control areas were determined. And the differences of these metal distributions as well as the estimation of possible mechanisms of the heavy metal excretion in the urine in relation to the dietary intake were statistically analyzed.Urinary Cd in the polluted area residents was higher than that of the control area residents, however, the ratio of urinary excretion of Cd among the polluted area residents to the control area residents was smaller than the ratio of fecal Cd excretion in the two area residents. This may suggest the more accumulation and retention of Cd among the Cd-polluted area residents, resulting in the appearance of less Cd concentration in the urine.The urinary Pb concentration in the polluted area residents also showed higher than those of the control area residents; this tendency was consistent with the results from the dietary and fecal Pb analyses. The essential metals in the urine, Cu and Zn, showed the different tendency that urinary Zn con-centration did not differ by area, whereas that urinary Cu did differ by area. These were not consistent with the results from the fecal analysis, suggesting the different metabolism of the essential metals in the human body.

Some metabolic interrelationships among cadmium,lead,copper and zinc: Results from a field survey in Cd-polluted areas in Japan Part one: Dietary intake of the heavy metals.

Ten dietary samples from each groups of residents in three cadmium- polluted areas and three control areas in Japan were analyzed to assess the daily intake of heavy metals such as cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn). The analysis disclosed that the daily Cd and Cu come chiefly from the rice and that the daily Pb and Zn come from the other food source in the everyday diet. Intake of heavy metals in man is highly dependent upon the geographical characteristics of the residing area. The Cd-polluted area residents take two to three times larger amounts of Cd than the control area residents and relatively larger amounts of Pb and Zn, and equal amount of Cu as compared to the control area residents. The daily intake of the four heavy metals in the control group showed similar values to those earlier reported.

Studies on excretion and uptake of calcium by rats after continuous oral administration of cadmium

The excretion and the uptake of Ca in rats were investigated in detail after the oral administration of CdCl 2 for various periods of time. The rats which had been pretreated with CdCl 2 for 1 month excreted 55% of orally administered 47Ca in feces, whereas the rats which had not been pretreated with CdCl 2 for the same period excreted only 20% of the orally administered 47Ca into feces. These facts indicate that the absorption of Ca from the gastrointestinal tract was lowered by the exposure of rats to Cd. Most of the excreted 47Ca was found in feces, even when Ca was administered iv. Thus, the rats which had been pretreated with CdCl 2 for 3 months excreted 80% of the iv administered Ca into feces. Furthermore, the uptake of iv administered 47Ca into bones was found to decrease up to 30% by the pretreatment of rats with CdCl 2 for 3 months. These observations support the hypothesis that Cd is one of the important factors in the development of the so-called “itai-itai” disease, which is a form of osteomalacia and an endemic disease in Cd-polluted areas in Japan.