Cadmium, copper and zinc in the urine of welders using cadmium-containing silver solder

Copper Homeostasis in Mammals, with Emphasis on Secretion and Excretion. A Review

One of the hallmarks of Cu metabolism in mammals is that tissue and fluid levels are normally maintained within a very narrow range of concentrations. This results from the ability of the organism to respond to variations in intake from food and drink by balancing excretion, which occurs mainly via the bile and feces. Although this sounds straightforward and we have already learned a great deal about aspects of this process, the balance between overall intake and excretion occurs over a high background of Cu recycling, which has generally been ignored. In fact, most of the Cu absorbed from the GI tract actually comes from digestive fluids and is constantly “re-used”. A great deal more recycling of Cu probably occurs in the interior, between cells of individual tissues and the fluid of the blood and interstitium. This review presents what is known that is pertinent to understanding these complexities of mammalian Cu homeostasis and indicates where further studies are needed.

Iron, copper and zinc levels in urine: relationship to various individual factors

Urinary Fe, Cu and Zn levels were determined in healthy people from S/C de Tenerife. Males showed higher (p < 0.01) urinary levels (micrograms/L and microgram per day) of Zn than females. However, females had higher daily urinary Fe and Cu excretions per kg of body weight (p < 0.05) than males. Urinary metal concentration, expressed as mg metal per g CT, better reflects daily excretion. Urinary levels of Zn and Cu were within the reference values, but the urinary levels of Fe were lower than that in most of the published data. An increase in daily Fe, Cu and Zn excretion (micrograms per day) with age up to 30 years was observed. An increase with weight and height was also observed. Concentrations and excretions of Zn were significantly (p < 0.015) lower when the urinary pH was above 7. With respect to the frequency of consumption of rich protein food, rich fiber food, coffee, tobacco, or alcohol, only significantly (p = 0.015) higher Zn concentrations and higher (p = 0.091) excretions were found in people that consume alcohol more than 3 times a week. A significant depletion of urinary Zn and Cu concentration and Fe excretion was found in the subjects who usually did physical exercise. Positive intermetallic correlations among the concentrations and excretions of the metals investigated were observed.

Correlation of cadmium, copper, manganese, and zinc levels in the urine of people in nonpolluted areas

Quantitative correlation among the four metals cadmium, copper, manganese, and zinc was examined in nearly 1500 urine samples collected from adult female inhabitants in 8 nonpolluted regions in various parts of Japan. In addition to a significant correlation between urinary cadmium and zinc as previously reported, copper levels significantly correlated with those of cadmium and zinc. In contrast, manganese did not show any significant correlation with cadmium, copper, or zinc. These findings are in agreement with the fact that cadmium, copper, and zinc are known to combine with metallothionein in vivo, whereas this is not the case with manganese.

Copper and zinc levels in serum and urine of cadmium-exposed people with special reference to renal tubular damage

Urinary copper and zinc concentrations and their serum levels were determined in women environmentally exposed to cadmium, including "itai-itai" disease patients and suspected patients, for evaluating the effect of cadmium exposure on metabolism of such essential metals as copper and zinc in human beings. Copper concentrations in the urine of cadmium-exposed women, especially "itai-itai" patients and suspected patients, were much higher than those of nonexposed women. Zinc concentrations in the urine of cadmium-exposed women, however, were not different from those of nonexposed women. Zinc levels in the serum of the "itai-itai" patients were somewhat lower than those of the nonexposed women. On the other hand, serum copper was almost equal in the cadmium-exposed and the nonexposed women. The correlation coefficient between beta 2-microglobulin amounts and copper concentrations in the urine of all women examined was as high as 0.95. It is concluded that exposure to cadmium will cause an increase in the excretion of copper in urine, which is attributable to renal tubular damage due to the cadmium exposure, and that urinary zinc excretion is not increased by cadmium exposure, even in the patients who suffer from severe renal tubular damage.