Cd Levels In Kidney Research Articles

Mitigating cadmium contamination of rice soils supporting tobacco–rice rotation in southern China: Win–win or lose–lose?

The present study evaluates the sustainability of tobacco-rice rotation by reducing the phytoavailability of cadmium (Cd) to rice by combining large-scale field sampling and regional investigations in southern China. The rotation involves frequent tillage and liberal application of nitrogen and phosphorus fertilizers, which increases yields but lowers soil pH. As a result, manganese is lost from soil and, at the same time, more soil Cd is taken up by rice and tobacco. The tendency to overcompensate for the Mn loss is influenced by soil properties, crop type, and economics of cultivation. Based on the scenario analysis, this tendency and the Cd uptake risks were estimated. Dietary intake of 83.3% of rice grain produced on the rotation fields would have adverse health effects on local male nonsmokers. Besides the rice, Cd in local tobacco leaf may lead to an increase in the kidney Cd levels of local male smokers (21.5 cigarettes per day) by 16.2-fold at age 50. Field trials and model estimations indicated that for a Cd concentration below 0.2 mg dry weight kg-1 in rice grain, the critical pH value in rice soils was ~ 6.0, and that for amorphous Mn oxide at pH 4.5–6.0 was 120 mg kg−1.

Cadmium and High-Fat Diet Disrupt Renal, Cardiac and Hepatic Essential Metals

Exposure to the environmental toxicant cadmium (Cd) contributes to the development of obesity-associated diseases. Obesity is a risk factor for a spectrum of unhealthy conditions including systemic metabolic dyshomeostasis. In the present study, the effects of whole-life exposure to environmentally-relevant concentrations of Cd on systemic essential metal distribution in adult mice fed a high-fat diet (HFD) were examined. For these studies, male and female mice were exposed to Cd-containing drinking water for >2 weeks before breeding. Pregnant mice and dams with offspring were exposed to Cd-containing drinking water. After weaning, offspring were continuously exposed to the same Cd concentration as their parents, and divided into HFD and normal (low) fat diet (LFD) groups. At 10 and 24 weeks, mice were sacrificed and blood, liver, kidney and heart harvested for metal analyses. There were significant concentration dependent increases in Cd levels in offspring with kidney > liver > heart. Sex significantly affected Cd levels in kidney and liver, with female animals accumulating more metal than males. Mice fed the HFD showed > 2-fold increase in Cd levels in the three organs compared to similarly treated LFD mice. Cadmium significantly affected essential metals levels in blood, kidney and liver. Additionally, HFD affected essential metal levels in these three organs. These findings suggest that Cd interacts with HFD to affect essential metal homeostasis, a phenomenon that may contribute to the underlying mechanism responsible for the development of obesity-associated pathologies.

Cadmium level trend in liver and kidney of pigs from Serbia during 2014-2018

Concentrations of cadmium (Cd) were measured in samples of liver (n=88) and kidney (n=226) of pigs within the Serbian National Residue Monitoring Program during 2014-2018. Levels of Cd were determined by inductively-coupled plasma mass spectrometry. All of the pigs had measurable amounts of Cd in liver and kidney, but none of the analyzed samples exceeded MRL for Cd – 0.5 and 1.0 mg/kg, respectively. The maximum Cd concentration in kidney amounting to 0.864 mg/kg was established in the first year of the residue monitoring program (2014). No statistically significant differences in Cd levels in liver samples during the examined period were observed, while statistical differences were established only between Cd levels in kidney collected in 2014 and 2015. On the basis of statistical analysis, it can be concluded that Cd levels have not increased in the analyzed organs during the investigated period.

The Protective Effects of Probiotic Bacteria on Cadmium Toxicity in Rats.

One of the useful properties of probiotic bacteria is their capacity to bind different targets, thus eliminating them through feces. It is supposed that one of these targets could be cadmium, a widespread environmental toxicant that causes various disturbances in biological systems. This study examined the protective effects of probiotic supplementation against cadmium-induced toxicity in the rat. The experiment was conducted in the course of 5 weeks. Animals were divided into four groups: (1) controls, (2) probiotics treated, (3) cadmium treated, and (4) probiotics + cadmium treated. The cadmium concentration was measured in the blood, liver, kidney, and feces, as well as the blood alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as biomarkers of the liver function. Histomorphological changes in the liver and kidney were also determined. Our results revealed that probiotics combined with cadmium increase this metal concentration in feces. As a result, blood, liver, and kidney Cd levels, as well as blood ALT and AST activities were lessened compared to the rat group treated with cadmium only. Besides, probiotics consumed simultaneously with cadmium attenuated histomorphological changes in the liver and kidney caused by cadmium. The rise in lactobacilli number in feces of rats treated simultaneously with cadmium and probiotics results in strong correlation with the increase of Cd concentration in their feces and the decrease of Cd concentration in their blood. We speculate that probiotics actively contribute to cadmium excretion through feces, probably, by its binding to their bacterial cell wall.

Kidney cadmium levels and associations with urinary calcium and bone mineral density: a cross-sectional study in Sweden.

BackgroundCadmium (Cd) can cause renal damage and osteoporosis after high-level exposure. Recently such effects, including increased urinary excretion of calcium, have been shown also at low-level exposure, as measured by Cd in blood or urine. However, associations with kidney Cd have not been examined. The aim of this study was to explore the relation between kidney Cd and urinary calcium excretion, or bone mineral density.MethodsCd was determined in kidney cortex biopsies from 109 living kidney donors. Serum was analyzed for ionized calcium, parathyroid hormone and vitamin D. Calcium was analyzed in overnight and 24-hour urine samples. Bone mineral density was measured in a subgroup of 67 donors. Associations between single variables were assessed by Spearman and Pearson correlation coefficients. Differences between independent groups were compared using Student’s t-test. For related samples, paired t-test was applied. Associations between urinary calcium and kidney Cd, ionized serum calcium, serum parathyroid hormone, inactive and active vitamin D and background variables were assessed using multiple linear regression and logistic regression.ResultsIn spite of relatively low kidney Cd levels (median 13 μg/g, range 1.5-55 μg/g) kidney Cd and urinary calcium were positively associated, mainly caused by an association in women. Donors with kidney Cd above the median (subgroup mean 23 μg/g) had significantly higher excretion of urinary calcium normalized for creatinine than those below the median (subgroup mean 7.3 μg/g). In women, also the excretion of Ca per hour was higher in those with high kidney Cd (24 hour sample mean 0.21 vs. 0.15 mmol/h; overnight sample 0.16 vs. 0.11 mmol/h). There were negative associations between kidney Cd and bone mineral density, most of which, however, disappeared in multivariate analyses.ConclusionsThis study provides support for an association between kidney Cd levels and urinary calcium excretion in women, but not in men. The results strengthen the case for preventive measures against Cd pollution.

Cadmium, mercury, and lead in kidney cortex of living kidney donors: Impact of different exposure sources,

Most current knowledge on kidney concentrations of nephrotoxic metals like cadmium (Cd), mercury (Hg), or lead (Pb) comes from autopsy studies. Assessment of metal concentrations in kidney biopsies from living subjects can be combined with information about exposure sources like smoking, diet, and occupation supplied by the biopsied subjects themselves. To determine kidney concentrations of Cd, Hg, and Pb in living kidney donors, and assess associations with common exposure sources and background factors. Metal concentrations were determined in 109 living kidney donors aged 24-70 years (median 51), using inductively coupled plasma-mass spectrometry (Cd and Pb) and cold vapor atomic fluorescence spectrometry (Hg). Smoking habits, occupation, dental amalgam, fish consumption, and iron stores were evaluated. The median kidney concentrations were 12.9microg/g (wet weight) for cadmium, 0.21microg/g for mercury, and 0.08microg/g for lead. Kidney Cd increased by 3.9microg/g for a 10 year increase in age, and by 3.7microg/g for an extra 10 pack-years of smoking. Levels in non-smokers were similar to those found in the 1970s. Low iron stores (low serum ferritin) in women increased kidney Cd by 4.5microg/g. Kidney Hg increased by 6% for every additional amalgam surface, but was not associated with fish consumption. Lead was unaffected by the background factors surveyed. In Sweden, kidney Cd levels have decreased due to less smoking, while the impact of diet seems unchanged. Dental amalgam is the main determinant of kidney Hg. Kidney Pb levels are very low due to decreased exposure.

Cadmium in moose kidney and liver – age and gender dependency, and standardisation for environmental monitoring

In the northern hemisphere moose has been found to be suitable as a monitoring animal for the presence of cadmium in the environment. The metal accumulates mainly in the kidney and the liver, with the rate of accumulation dependent on age and possibly also on gender. Collection of tissue material often results in sample selections with disparate age and gender composition, which makes comparison between different regions and different studies difficult. A previous large scale investigation of metals in kidney and liver from moose in Sweden provided Cd data (n = 3,817 and 3,802, respectively) to further explore the relation between Cd accumulation and age/gender. Based on local averages, the individual deviations were analysed with respect to the factors age and gender resulting in an 'ageing function' for each gender and organ. In addition, estimates of the pure individual variations were obtained; the standard deviations correspond to a factor 1.7-1.9 for the Cd concentration, which indicates that 25-30 samples are needed to give a representative mean value (with RSD approximately 10%). In order to be able to compare results from different studies, all individual results can be transformed to represent a 'standard moose' with respect to age and gender. A comparison along these lines was undertaken between Cd levels in Alaska and Sweden. Finally, a relationship between the Cd levels in kidney and liver was derived, providing at least rough estimates for kidney from liver values (or vice versa).

한국에 도래하는 아비류의 카드뮴과 납 축적 레벨

부산 연안에서 월동 중 사망한 아비류 3종 25개체의 체내 조직 중 카드윰과 납 축적 레벨을 밝히고 오염 수준을 파악하였다. 카드뮴과 납 농도는 아비, 회색머리아비, 큰회색머리아비 3종간에 종간차가 인정되지 않았다(p>0.05). 조직 중 카드뮴 농도는 0.02<TEX>$\sim$</TEX>18.3<TEX>${\mu}g/g$</TEX>의 범위로 신장에서 가장 높고 뼈에서 가장 낮은 정상적인 조직분포를 보였다. 간 조직 중 카드뮴 농도 (3.45<TEX>$\sim$</TEX>6.34<TEX>${\mu}g/g$</TEX>)는 다른 나라에서 보고된 아비류 농도(ND<TEX>$\sim$</TEX>7.11<TEX>${\mu}g/g$</TEX>)와 비슷하였다. 큰회색머리아비 1개체를 제외한 모든 개체의 신장 조직 중 카드뮴 농도는 비오염수준(<30 <TEX>${\mu}g/g$</TEX>)에 해당하였다. 조직 중 납 농도는 0.03<TEX>$\sim$</TEX>1.49<TEX>${\mu}g/g$</TEX>의 범위로 뼈에서 가장 높고 근육에서 가장 낮은 정상적인 조직분포를 보였다. 간 조직 중 납 농도(0.19<TEX>$\sim$</TEX>1.22<TEX>${\mu}g/g$</TEX>)는 보고된 정상적인 아비류 농도와 비슷하였다. 대부분의 간 조직 중 납 농도는 비오염수준(0.15<TEX>$\sim$</TEX>3.0 <TEX>${\mu}g/g$</TEX>)에 해당되었다. We investigated Cd and Pb accumulation levels in tissues of 25 individuals of three species of loons wintering in coastal areas of Busan, Korea. Their liver, muscle, kidney and bone tissues were analyzed for Cd and Pb concentrations. Significant difference of Cd and Pb concentrations was not found among the three species (p>0.05). Individual Cd values ranged from 0.02 to <TEX>$18.3{\mu}g/g$</TEX>. Cd concentrations were highest in kidney and lowest in bone. Levels (3.45<TEX>$\sim$</TEX>6.34 <TEX>${\mu}g/g$</TEX>) of all the analyzed liver Cd were similar in comparison with those (ND<TEX>$\sim$</TEX>7.11<TEX>${\mu}g/g$</TEX>) reported for the loons in different areas. All but one (Gavia arctica) of kidney Cd levels were lower than the exposed level (>30 <TEX>${\mu}g/g$</TEX>). Individual Pb values ranged from 0.03 to 1.49 <TEX>${\mu}g/g$</TEX>. Pb concentrations were highest in bone and lowest in muscle. Liver Pb levels in this study were similar to those of normal loons reported from different countries. Based on hepatic Pb levels, almost all of the samples were classified as background level (0.15<TEX>$\sim$</TEX>3.0 <TEX>${\mu}g/g$</TEX>).

Accumulation of heavy metals in circumpolar willow ptarmigan (Lagopus l. lagopus) populations

A circumpolar survey of heavy metals in willow ptarmigan liver and kidney revealed considerable variations in Cd content in Canada and Scandinavia. The Cd content in central Canada was comparable with that in Scandinavia and Russia, at least for kidney. However, in both liver and kidney the median for Canada as a whole was much higher than in the other countries. Some Canadian locations had exceptionally high levels, several birds having >50 mg kg(-1) in liver and >400 mg kg(-1) in kidney. In Norway, the Cd content was highest in central mountain areas in south Norway and inland locations in the two northernmost counties. Five locations in central and north Norway showed mean Cd levels in kidney above 100 mg kg(-1). It is difficult to evaluate regional differences in Sweden, but most locations had the same Cd level as moderately contaminated locations in Norway. Cd levels in Russia were comparable to moderately contaminated locations in the other countries. Due to a high intake of willow, naturally rich in Cd, direct comparison of the Cd level in willow ptarmigan from different locations cannot reveal the effects of long-range pollution. The Pb concentration in willow ptarmigan kidney and liver varied significantly in Norway and Canada, but not in Sweden and Russia. Levels in Sweden and Russia were comparable to those in Canada and low levels in Norway. The highest median value from all locations within countries was found in Norway, both in liver and kidney. The highest Pb content was found in south Norway, indicating an effect of long-range pollution in willow ptarmigan. The level in western Canada was significantly higher than in central Canada. The Hg content in liver varied significantly from one location to another in all the countries and in kidney everywhere except Sweden. In Scandinavia, there is no distinct regional pattern. Canada had a significantly higher Hg level in central than western regions in both tissues the opposite of that found for Cd and Pb. Cu and Zn showed significant variations from one location to another in liver and kidney in Canada and Norway, but only in kidney in samples from Sweden. Comparison between western and central Canada revealed a significant difference for Cu in liver, samples from central Canada having more. There are no significant differences from one country to another, but some localities in Canada seem to have higher Cu concentrations in kidney than are found in Scandinavia and Russia.

Renal dysfunction induced by cadmium: biomarkers of critical effects

Cadmium (Cd) is cumulative poison which can damage the kidneys after prolonged exposure in the industry or the environment. Renal damage induced by Cd affects primarily the cellular and functional integrity of the proximal tubules, the main site of the renal accumulation of the metal. This results in a variety of urinary abnormalities including an increased excretion of calcium, amino acids, enzymes and proteins. These effects have been documented by a large number of studies conducted during more than two decades in experimental animals and in populations environmentally or occupationally exposed to Cd. There is now a general agreement to say that the most sensitive and specific indicator of Cd-induced renal dysfunction is a decreased tubular reabsorption of low molecular weight proteins, leading to the so-called tubular proteinuria. beta2-microblobulin, retinol-binding protein and alpha1-microglobulin are the microproteins the most commonly used for screening renal damage in populations at risk. Tubular dysfunction develops in a dose-dependent manner according to the internal dose of Cd as assessed on the basis of Cd levels in kidney, urine or in blood. Depending on the sensitivity of the renal biomarker and the susceptibility of the exposed populations, the thresholds of urinary Cd vary from 2 to 10 microg/g creatinine. The thresholds associated with the development of the microproteinuria, the critical effect predictive of a decline of the renal function, is estimated around 10 microg/g creatinine for both occupationally and environmentally exposed populations. Much lower thresholds have been reported in some European studies conducted on the general population. These low thresholds, however, have been derived from associations whose causality remains uncertain and for urinary protein increases that might be reversible. Cd-induced microproteinuria is usually considered as irreversible except at the incipient stage of the intoxication where a partial or complete reversibility has been found in some studies.

Monitoring of cadmium in the chain from soil via crops and feed to pig blood and kidney

The relationships between cadmium (Cd) levels in soil, feed crops, feed concentrate, pig feed mixture, water, pig blood, and kidney from 49 farms were investigated and the possibility to use pig kidney as a bioindicator of available Cd in the agricultural environment was evaluated. There were correlations between Cd levels in soil and wheat, between wheat and barley, and between feed and kidney. The accumulation ratio between Cd levels in feed and kidney was on average 3. Animals from the same farm, raised in the same environment, given the same feed, and slaughtered at the same age had Cd levels in kidney and blood that could differ several times. This great variation, together with a considerable Cd contribution from nonlocally produced feed ingredients (concentrates), limits the possibilities to use Cd in pig kidney as an indicator of the available Cd in the local environment.

Metal levels in body tissues, forage and fecal pellets of elk ( Cervus elaphus) living near the ore smelters at Sudbury, Ontario

Ontario’s only free-ranging elk herd located at Burwash–French River has been subjected to the influence of historic copper–nickel–iron (Cu–Ni–Fe) ore smelting operations within the Sudbury area. Metal levels in selected body tissues, preferred forage items and fecal pellets were determined, and their potential effects on health and reproductive viability assessed. Significant age effects were apparent in 13 out of 31 tissue metal values obtained, with most age-related differences attributable to elevated concentrations in fetal tissues. Cu and zinc (Zn) levels were four to six times higher in livers and one and a half to two times higher in the bones of fetuses as compared to post-natal animals. Enhanced pre-natal tissue burdens were also noted for cobalt (Co), Ni and lead (Pb) in muscles. However, mean cadmium (Cd) levels in kidney, liver and muscle tissues, as well as hepatic Fe concentrations, showed significant increases with age. Although Cd levels in the kidneys of older elk were still well below the reported threshold for irreversible organ damage, and not considered to be health-threatening, detailed histological study of the cortical tissues for subtle pathotoxicological effects may be warranted. Unlike renal and hepatic tissues, Cd concentrations in skeletal muscle were minimal and within levels considered acceptable for human consumption. Forage species collected in the elk range generally showed higher (two to eight times) Ni and Fe levels than the corresponding plants from a non-contaminated reference site. The highest Ni and Fe burdens were carried by eastern white cedar, a preferred winter food item for elk. No consistent site-related trends were demonstrated by Cu, Zn, Co, Pb, chromium (Cr) and Cd forage levels. Mean metal concentrations in fecal pellets generally exceeded the mean composite forage levels by a factor of 3, except for Ni, which was five times more concentrated in feces. Significantly elevated Ni and Fe levels in preferred browse species and fecal pellets of the Sudbury-area elk could be of concern and warrant further investigation.

The accumulation of lead, zinc, cadmium and fluoride in the wood mouse (Apodemus sylvaticus L.)

The concentrations of Pb, Zn, Cd, and fluoride were determined in liver, kidney and femur tissues 30 days after wood mice were provided with water containing soluble salts of these elements in their drinking water. There were eight treatment groups: Pb, Zn, Cd, and fluoride only; Zn and Cd (ZnCd); fluoride and Pb (FPb); fluoride, Pb, Zn, and Cd (FPbZnCd); and a control. Lead concentrations were highest in bone but were also significantly higher in the kidney but not liver when compared to the control. The highest kidney Pb levels were in the FPbZnCd treatment but they were not significantly higher than the Pb only group. Zinc concentrations were highest in kidney and not femur as is usually the case in field caught animals. Cadmium was also highest in the kidney in the high Cd treatments, however, the ZnCd treatment group had significantly lower kidney Cd levels than the Cd only group demonstrating the antagonistic effect of high Zn on Cd accumulation. This effect was reversed when high fluoride and Pb were also present (in the FPbZnCd group) and the kidney Cd reached its highest level. Fluoride showed the typically high levels in bone with only the combined treatment (FPbZnCd) showing a significant increase in kidney fluoride. These results are discussed in terms of the accumulation in wild small mammals caught in polluted sites particularly grasslands established on fluorspar wastes.

Schedule dependency of a cadmium-complexing dithiocarbamate analog in mice

A number of dosing regimens was assessed to determine the optimum schedule of administration of N-(4-methoxybenzyl)- N-dithiocarboxy- d-glucamine (MeOBDCG) in depleting whole-body, renal and hepatic levels of metallothionein-bound cadmium (Cd) in mice. A comparison of 4.0 mmol/kg given as a single injection versus 0.5 mmol/kg given as 8 hourly injections revealed the latter regimen to be superior in reducing renal Cd levels, but less effective than a bolus dose in lowering hepatic Cd concentrations. Administration of 1.33 mmol/kg for 3 consecutive days or 0.8 mmol/kg for 5 days effected a more extensive depletion of renal Cd concentrations than did a single injection of 4.0 mmol/kg. Three injections of 1.0 mmol/kg given at 4- to 7-day intervals were generally more effective in reducing renal Cd concentrations than were 3 consecutive daily injections in mice which had low or moderately high total Cd burdens. The lowest effective dose of MeOBDCG in lowering whole-body, liver and kidney Cd levels when given repetitively was about 0.2 mmol/kg. While schedule variations did not alter appreciably the whole-body Cd reductions at any given total dose of MeOBDCG, repetitive dosing schedules in which injections were given at intervals of several days rather than daily were typically more effective in reducing renal Cd levels. Based upon consideration of pharmacological response as influenced by body surface area, it was calculated that doses of MeOBDCG of the order of 2.0 g/d may be effective in reducing renal Cd levels in individuals with chronic renal dysfunction secondary to chronic Cd intoxication.

Levels of lead, cadmium and other elements in mink and otter from Ontario, Canada

Concentrations of Pb, Cd, Cu, Ni, Fe, Zn, Mn, Ca, P, Mg and S were measured in tissues of mink ( Mustela vision) and river otter ( Lutra canadensis) from five areas of Ontario, Canada. Bone Pb levels in both species were lowest in animals from the collection site most remote from industrial activity and atmospheric deposition of pollutants. Mean liver and kidney Cd levels were also different between collection sites and may reflect natural and/or anthropogenic sources. Copper levels in liver, but not kidney, were elevated in mink and otter from the heavily Cu-contaminated Sudbury region. However, tissue levels did not reflect environmental loading of other metals, such as Fe, Ni and Zn, in the Sudbury area. This may be a function of effective homeostatic regulation in mammals, or low potential for biomagnification of these elements.

Effects of sodium N-methyl-N-dithiocarboxyglucamine on cadmium distribution and excretion

Sodium N-methyl-N-dithiocarboxyglucamine (MDCG) was evaluated for its efficacy in mobilizing and promoting excretion of metallothionein-bound 109Cd using mice which had received 0.03 mg of CdCl 2·2.5H 2O along with 1.0 >Ci of 109CdCl 2 three weeks earlier. The MDCG-induced change in the fecal excretion of Cd ranged from a 15-fold increase over the control rate at the lowest dose level used (2.2 mmol/kg; 684 mg/kg) up to a 72-fold increase at the highest dose (8.8 mmol/kg; 2736 mg/kg) following three daily injections. The latter treatment regimen resulted in a fecal excretion of almost 30% of the administered Cd over a 3-day period of observation. Urinary Cd excretion was insignificant in both the control and treated groups. The whole body burden of Cd was reduced by over 50% following seven thrice-weekly i.p. injections of MDCG at 8.8 mmol/kg. There was a 60–65% reduction in both the liver and kidney Cd levels following the same treatment regimen. Radioassay of ten other organs and tissues revealed only modest changes. Testicular Cd was decreased slightly at the highest dose level, and heart tissue from each treated group contained slightly more Cd than controls. Results indicated a rather marked specificity of MDCG in lowering the Cd content of two organs most susceptible to Cd-induced toxicity.

In vivo measurement of critical level of kidney cadmium: dose effect studies in cadmium smelter workers.

In vivo measurements of kidney and liver cadmium burdens were obtained in 82 industrially exposed workers and ten control subjects. Kidney cadmium levels ranged from 0.9 mg to 57 mg, and liver concentrations ranged from 0.8 ppm to 120 ppm for the industrial group. Comparison values for the control group were 0.4 mg to 11.8 mg for the kidney and 0.6 ppm to 7.9 ppm for the liver. A biphasic relationship between kidney Cd levels and liver Cd levels was observed. The kidney and liver Cd levels showed an increase until approximately a 40 ppm concentration was reached in the liver. Thereafter, the kidney levels decreased as the liver concentration continued to increase. The kidney cadmium level at which this change occurred was approximately 31 mg for the total kidney. Further estimates of the critical level, based on years of exposure and renal dysfunction (beta 2-microglobulin, proteinuria), yielded estimates of 31 mg to 42 mg cadmium (300-400 micrograms/gm for the renal cortex).

Cadmium Uptake from Feed and Its Distribution to Food Products of Livestock

Distribution of cadmium (Cd) into the edible products of three species of food-producing animals was investigated during long-term dietary administration of supplemental cadmium chloride. Cows were exposed to 0.2 (control), 2.4, and 11.3 ppm Cd on whole ration basis for a period of three months followed by a three-month period on control ration. No accumulation of Cd occurred in milk, muscle, or bone at any of the time periods. A dose-related increase of Cd was observed in liver and kidney. The Cd concentration in these organs showed a gradual rise even when the animals were given control ration for three months after an initial three-month exposure to Cd; this observation suggests a mobilization and redistribution of this metal from other tissues. Dietary Cd levels in swine rations were 0.2, 2.4, and 10.1 ppm. The highest level of Cd produced a slightly reduced growth rate in swine. No accumulation of Cd was observed in muscle, bone, or brain. Liver and kidney showed a treatment and time-related increase in cadmium values at 6 and 12 weeks on experiment. During a three-month depletion phase after an initial three months of Cd administration, no further change in liver and kidney Cd levels was observed. White Leghorn chickens were treated by administering 0.3, 1.9, and 13.1 ppm Cd in their diets for up to 6 months. No accumulation of Cd occurred in eggs or bones. A slight increase of Cd level was observed in chicken muscle after six months of exposure. Liver and kidney had the highest levels of Cd, which showed a dose and time-related increase in these organs. No depletion of liver and kidney Cd was seen during seven weeks following a six-week treatment period. In all three species, the kidney Cd levels were severalfold higher than those of liver at all dietary levels. In swine, the renal cortex and medulla had similar Cd concentration in control animals but in all animals exposed to supplemental Cd, a dramatic rise in Cd levels in renal cortex was observed. Medullary Cd did not show a proportional time and dose-related increase in Cd levels, although the levels showed some increase. In kidney and liver of all three species the Cd levels showed a positive correlation with the amount of Cd-binding protein in these tissues. Induced levels of this metal-binding protein may explain accumulation and persistence of Cd-residues in these organs. In all three species, the concentrations of renal Cd-binding protein increased at a rate greater than those in liver. Although the food-producing animals may act as an effective filter of Cd in the case of an environmental increase of this metal, consumption of visceral organs from such animals may pose a hazard. This is particularly critical since the daily intake of Cd in human diet is already estimated to exceed the tolerance limits suggested by WHO/FAO.

Cadmium uptake from feed and its distribution to food products of livestock.

Distribution of cadmium (Cd) into the edible products of three species of food-producing animals was investigated during long-term dietary administration of supplemental cadmium chloride. Cows were exposed to 0.2 (control), 2.4, and 11.3 ppm Cd on whole ration basis for a period of three months followed by a three-month period on control ration. No accumulation of Cd occurred in milk, muscle, or bone at any of the time periods. A dose-related increase of Cd was observed in liver and kidney. The Cd concentration in these organs showed a gradual rise even when the animals were given control ration for three months after an initial three-month exposure to Cd; this observation suggests a mobilization and redistribution of this metal from other tissues. Dietary Cd levels in swine rations were 0.2, 2.4, and 10.1 ppm. The highest level of Cd produced a slightly reduced growth rate in swine. No accumulation of Cd was observed in muscle, bone, or brain. Liver and kidney showed a treatment and time-related increase in cadmium values at 6 and 12 weeks on experiment. During a three-month depletion phase after an initial three months of Cd administration, no further change in liver and kidney Cd levels was observed. White Leghorn chickens were treated by administering 0.3, 1.9, and 13.1 ppm Cd in their diets for up to 6 months. No accumulation of Cd occurred in eggs or bones. A slight increase of Cd level was observed in chicken muscle after six months of exposure. Liver and kidney had the highest levels of Cd, which showed a dose and time-related increase in these organs. No depletion of liver and kidney Cd was seen during seven weeks following a six-week treatment period. In all three species, the kidney Cd levels were severalfold higher than those of liver at all dietary levels. In swine, the renal cortex and medulla had similar Cd concentration in control animals but in all animals exposed to supplemental Cd, a dramatic rise in Cd levels in renal cortex was observed. Medullary Cd did not show a proportional time and dose-related increase in Cd levels, although the levels showed some increase. In kidney and liver of all three species the Cd levels showed a positive correlation with the amount of Cd-binding protein in these tissues. Induced levels of this metal-binding protein may explain accumulation and persistence of Cd-residues in these organs. In all three species, the concentrations of renal Cd-binding protein increased at a rate greater than those in liver. Although the food-producing animals may act as an effective filter of Cd in the case of an environmental increase of this metal, consumption of visceral organs from such animals may pose a hazard. This is particularly critical since the daily intake of Cd in human diet is already estimated to exceed the tolerance limits suggested by WHO/FAO.