Ppm Cadmium Research Articles

Heavy metal action on transintegumentary absorption of glycine in two annelid species

Absorption of 14C-glycine from ambient sea water across the body surface of the oligochaete Enchytraeus albidus Henle was, after 6 h preincubation, significantly reduced in the presence of 0.1 to 0.15 ppm mercury, 0.25 ppm copper, 1.5 ppm silver, and 2 ppm cadmium. Addition of heavy metal salts reduced maximum uptake rates (Vmax), without affecting transport constants (Kt). Influx of 14C-glycine remained unchanged in the presence of up to 10 ppm aluminium, chromium, iron, lead, molybdenum, vanadium, and zinc. Effects of up to 150 ppm nickel, manganese, cobalt and selenium were negligible. Inhibition of glycine absorption by mercury and cadmium in the polychaete Nereis diversicolor Muller is almost identical with results presented for E. albidus. Transintegumentary solute absorption in soft-bodied marine invertebrates obviously represents a suitable biological function for studies on heavy metal toxicity. The close relationship between rates of heavy metal absorption, inhibition of transintegumentary glycine uptake, and acute toxicity is discussed.

Toxicité à long terme du cadmium administré à trés faible dose chez le rat: Réponse à l'agression par le froid

The toxic action of cadmium, as well as its interaction with a cold stress, has been studied on four groups of COBS-CD rats (10 ♂, 10 ♀), absorbing 0 (TT and TF) or 2.5 (CdT, CdF) ppm of cadmium (drinking water). After 12 months under observation, the TF and CdF groups were housed at +1°C for 48 hr. In the course of, or just after, this stress, various urinary parameters (volume, Na +, K +, urea, creatinine) and blood parameters (hemoglobin, Na +, K +, Ca 2+, Cl −, P i, urea, creatinine, blood sugar) were measured. In the CdT groups, cadmium was responsible for lower urea concentrations in urine (16%), and lower phosphate and creatinine in serum (16 and 10%). Under cold stress, treated animals (CdF) reacted differently than the control animals (TF): less polyuria, and no trace of hypokalemia, hypophosphatemia, and hyperglycemia; as opposed to the TF groups, the presence of hypercreatinemia (15%) and hypocalcemia (6%). These results hint at the existence of latent noxious effects related to the well-known toxicity of high doses of cadmium.

Cadmium-induced tissue specific changes in drug biotransformation rates in rats

Cadmium was administered into male rats in drinking water as cadmium chloride at a concentration equivalent to 250 ppm of cadmium for 2 and 8 weeks. The cadmium concentration in the liver microsomes was 0.85 +/- 0.11 microgram/g (wet wt) and in the supernatant 29.6 +/- 1.1 microgram/g and in the renal microsomes 1.30 +/- 0.30 microgram/g (w.wt) and in the supernatant 24.4 +/- 3.2 microgram/g after 8 weeks. In the intestinal postmitochondrial supernatant fraction the cadmium concentration was 14.2 +/- 1.0 microgram/g (wet wt) after 8 weeks administration. There was a slight increase in the hepatic cytochrome P-450 level, no changes in the hepatic p-nitroanisole O-demethylase and NADPH cytochrome c reductase activities and a clearcut induction in the hepatic aryl hydrocarbon hydroxylase activity after 8 weeks cadmium exposure. Renal activities followed mainly those of the liver. No changes were found in the hepatic UDPglucuronosyltransferase activity and a slight activation was present in the renal activity. The intestinal activities were markedly depressed after cadmium exposure. The results suggest that cadmium administration changes the drug biotransformation rates differently in various tissues.

Effect of chronic low-level cadmium intoxication on the Haversian remodeling system in dogs.

This experiment was carried out in order to determine whether the chronic administration of low doses of cadmium resulted in an alteration of the haversian bone remodeling system in dogs. Two pairs of littermate beagles were administered 25 ppm cadmium chloride in their drinking water for 6 months. Four beagles matched for age and sex from the same colony served as controls. By means of fluorescent labeling, we measured haversian bone remodeling parameters according to the techniques described by Frost. Statistical analysis of the results showed significant changes at the 0.01 level in: activation frequency, appositional rates, and number of osteoid seams. At the 0.05 level, significant differences were found in the number of resorption spaces and the bone formation rate. In the absence of other evidence indicative of an alteration in the internal milieu of the dogs, it is concluded that a direct toxic action of cadmium on the mechanisms of activation of cells responsible for the creation and formation of new haversian systems cannot be excluded.

Effects of Certain Inorganic Elements and Urea on in Vitro Dry Matter Disappearance of Milo Stalks

Ground milo stalks were digested with three levels of each calcium (10, 100 and 190 ppm), phosphorus (225, 350 and 475 ppm), magnesium (50, 100 and 150 ppm) and urea (.1, .3 and .5 g of nitrogen per liter) to determine effects on in vitro dry matter disappearance and to detect interactions among these nutrients. Treatment combinations were first screened to determine optimum levels of nutrients. In experiment II, 10% of the ground milo stalks was replaced by 50 mg of glucose or starch with .1, .3, .5 or .7 g of nitrogen (as urea) per liter. The third experiment included iron (0 to 12 ppm), strontium (0 to 20 ppm), zinc (0 to 12 ppm), cadmium (0 to 5 ppm) and manganese (0 to 24 ppm). Calcium at 190 ppm depressed in vitro dry matter disappearance. Phosphorus had no effect at the levels tested. Magnesium lowered digestibility linearly. Urea nitrogen depressed in vitro dry matter disappearance when levels exceeded .3 g per liter. Depressing effects of calcium, magnesium and urea-nitrogen appeared cumulative, as no interactions were observed in the experiment. Substitution of small quantities of fermentable carbohydrate for equal weight of milo stalks did not improve in vitro dry matter disappearance except at the highest level (.7 g/1) of urea-nitrogen. Iron, strontium and zinc had no effect on in vitro dry matter disappearance of milo stalks. Manganese addition beyond 4 ppm tended to reduce in vitro dry matter disappearance, and a definite depression occurred with 24 ppm manganese. With 3 ppm cadmium, in vitro dry matter disappearance was higher than with 0, 1 or 2 ppm. Intermediate values were obtained with 4 and 5 ppm cadmium.

Emergence of the midge chironomus tentans when exposed to heavy metal contaminated sediment

This experiment tested the effects of heavy metal contaminated sediment on emergence of chironomids. The number of adults emerging from test chambers containing an uncontaminated sediment and ones with sediment containing 1030 ppm cadmium (Cd), 17,300 ppm zinc (Zn), and 1640 ppm chromium (Cr) were observed for 14 days. It was found that emergence was reduced by over three times and delayed for two days in the heavy metal contaminated sediment.

Histopathologic effects of dietary cadmium on kidneys and testes of mallard ducks.

Mallard ducks fed 2, 20, or 200 ppm cadmium chloride were sacrificed at 30, 60, and 90 d. No mortality occured during the study and body weights remained unchanged. Kidney weights of the 200-ppm group were significantly greater after 60 and 90 d than those of controls; also, testis weights were significantly lower after 90 d. Kidneys of ducks fed 2 and 20 ppm cadmium were relatively unaffected; however, slight to severe kidney lesions were found in the 200-ppm group after 60 d of treatment. No significant lesions were found in mallard testes after feeding 2 ppm cadmium in the diet, and only a few birds in the 20-ppm group showed slight to moderate gonad alterations. After 90 d of treatment, however, testes of males fed 200 ppm had atrophied and the spermatogenic process had ceased. This study should provide important information for the interpretation of cadmium levels found in kidneys and testes of wild ducks.

Cadmium Uptake and Distribution in Tolerant and Non-Tolerant Populations of Holcus lanatus Grown in Solution Culture

Cadmium uptake and distribution between roots and shoots of a tolerant and a non-tolerant population of Holcus lanatus were studied with reference to both concentration and total cadmium content. The uptake of cadmium into roots of both normal and tolerant plants from nutrient solutions containing 1 ppm cadmium is extensive and in normal plants as much as 90% of the whole plant cadmium remains in the roots but translocation allows shoot concentrations to reach 145 ppm. In tolerant plants translocation of cadmium to shoots is further reduced with a concomitant increase of cadmium concentration in the roots. These effects are shown to be due to differences in biomass and metal uptake of the two populations.

Cadmium-induced fetal growth retardation in the mouse.

Exposure of mice to 10, 20, or 40 ppm cadmium in their drinking water throughout pregnancy resulted in various degrees of fetal growth retardation. The newborn mice, as well as being smaller than normal, were severely anemic. Parenterally administered iron completely prevented the cadmium induced fetal growth retardation and anemia. The significance of a possible relationship of small-for-date babies with cigarette smoking and cadmium intake was discussed.

Early signs of oral and inhalative cadmium uptake in rats

Female wistar rats, 170--190 g, were exposed for 90 days to cadmium oxide aerosols containing 25 and 50 microgram Cd/m3 and for 63 days to 100 microgram Cd/m3. Simultaneously female wistar rats, 170--190 g, were fed 25, 50, and 100 ppm cadmium in drinking water for 90 days. After inhalation and ingestion of the metal, there were comparable kidney cadmium levels, but higher liver and blood levels after oral uptake. Coincident with the higher blood cadmium concentrations, proteinuria was observed only after oral administration. Likewise, there was a significant decrease of serum iron after ingestion and no lowering of the serum iron after inhalation of the metal. The inhalation led to a marked dose dependent weight increase of the lungs, which was followed by an impairment of gas exchange. Obviously, after inhalative cadmium uptake of 90 days pulmonary changes precede renal damage.

Sediment contamination and benthic macroinvertebrate distribution in a metal-impacted lake

Sediment contamination and benthic macroinvertebrate distribution were studied in Palestine Lake, Indiana, a public 80-ha system contaminated by effluents from a nearby electroplating plant. Trace metal levels in the upper 3 cm of sediment ranged from a high of 969 ppm cadmium, 14,032 ppm zinc and 2106 ppm chromium (dry weight basis) near the influent ditch, to a low of 4 ppm cadmium, 139 ppm zinc and 38 ppm chromium in the uncontaminated eastern basin of the lake. The midge Chironomus tentans was absent from areas of highest contamination; how ver, midge numbers increased to an average of 28 individuals/grab sample in the eastern basin. Specimens of the aquatic oligochaete Limnodrilus sp. were abundant (89/sample) in the most heavily impacted areas of the lake and scarce (3·4/sample) in the eastern basin.

Partition of cadmium and manganese between coexisting sphalerite and galena from some Japanese epithermal deposits

Sphalerites from Japanese epithermal Pb-Zn vein-type deposits, namely, Yatani, Oizumi and Hosokura, contain 2900–3400 ppm cadmium and 760–2100 ppm manganese. And galenas from the same deposits contain cadmium and manganese 19.2–26.9 ppm and 7.8–218.3 ppm, respectively. The temperatures, evaluated from the partition of cadmium between coexisting sphalerite and galena, are consistent within a total range of 150°C at maximum within an individual deposit. No systematic change with depth can be observed at the Shoko-hi vein, Hosokura mine and Hompi vein, Yatani mine. In several samples, the temperatures obtained from the partition of cadmium have been compared with those obtained from sulfur isotope fractionations. Iron content in sphalerite coexisting with pyrite indicates that the deposition of ore minerals at these deposits may have taken place from ore-forming solutions in which H2S or HS− was the predominant dissolved sulfur species, and the solutions may have been free from in situ oxidation or reduction.

Hypertension following Chronic, Very Low Dose Cadmium Feeding

Exposing female Long-Evans rats to 0.1, 0.25, or 0.5 ppm of cadmium in drinking water for 6 to 18 months from the time of weaning induced a statistically significant average increase in systolic pressure of 10 to 24 mm Hg, and there was no evidence of cadmium toxicity. Comparable exposure to 0.01 or 0.03 ppm of cadmium was much less effective in raising pressure and probably had no pressor effect. After 18 months of exposure, the average renal cadmium level for the “0.1 ppm cadmium group” approximated 1 μg/g in contrast to more than 40 μg/g for the standard “5 ppm group” and less than 0.1 μg/g for the control group.

Sublethal effects of heavy metal contaminated sediment on midge larvae (Chironomus tentans)

Chironomid larvae were maintained for 17 days in sediments with various heavy metal levels. The control sediment had levels of 0.6 ppm cadmium, 17 ppm chromium and 77 ppm zinc. The most contaminated sediment had levels of 1030 ppm cadmium, 1640 ppm chromium, and 17300 ppm zinc. The mean length and weight of the larvae from the control sediment were 1.83 cm and 2.86 mg. The mean length and weight of larvae from the most contaminated sediment were 0.82 cm and 0.20 mg. A linear relationship was found for the square root of length versus metal levels in the sediment.

Avoidance response of Midge Larvae (Chironomus Tentans) to sediments containing heavy metals

Avoidance reactions of chironomid larvae to contaminated sediment taken from a heavy metal impacted lake were studied. Heavy metal levels in the test sediment ranged from background of 0.6 parts per million (ppm) cadmium, 77 ppm zinc and 17 ppm chromium to a maximum of 1,029 ppm cadmium, 17,262 ppm zinc and 2,106 ppm chromium. A linear relationship was established between cadmium and zinc levels in the sediment and avoidance by chironomids.

Effect of chronic oral cadmium exposure and withdrawal on cadmium residues in organs of mice.

The effects of chronic oral administration of cadmium on kidney and liver residues in mice were studied. The mice were given either 0, 3, or 300 ppM cadmium as cadmium chloride in deionized drinking water for 10 weeks, and were given deionized water for the remainder of the study. The results showed that with 300 ppM Cd there was accumulation in liver and kidney tissue at approximately a 1 : 1 ratio. After 20 days withdrawal, cadmium residues in the liver declined, and by 180 days were approximately 50% of the concentration at the time of withdrawal. The concentration of Cd in renal tissue, especially in mice exposed to 300 ppM Cd, remained relatively constant, or was slightly increased during 180 days after withdrawal from Cd exposure. Thus the liver : kidney ratios changed to 1 : 1.5 at 40 days withdrawal and 1 : 2 after 180 days. For chronic exposure, the biological half life of Cd in liver tissue was approximately 180 days as compared to 43 to 63 days following single oral doses or injections of Cd, as reported by other workers.

Effects of dietary and inhalative cadmium on hemoglobin and hematocrit in rats.

Th dfference of the effects of dietary and inhalative cadmium on hemoglobin and hematocrit was investigated using Wistar male rats. For the inhalation studies, rats were exposed to CdCl/sub 2/ aerosols (0.2 mg Cd/m/sup 3/) for 66 days. For the dietary experiments the rats received 25, 50 and 100 ppM cadmium as CdCl/sub 2/ in drinking water. The following parameters were measured: the body weights of the animals, hematocrit and hemoglobin in blood, and the Cd content of liver and kidney. The results showed a retardation of growth in the aerosol-exposed group and the group with 100 ppM oral Cd intake. The relation of the Cd content of kidney to liver averaged 1.7 for the oral-exposed groups and 4.4 for the inhalation-exposed groups. The hematocrit and hemoglobin values for the inhalation-exposed rats showed no significant differences when compared to the controls, but the values for the dietary cadmium group showed a significant reduction.

Semichronic oral toxicity of cadmium: 2. Studies on dogs

Cadmium in the form of CdCl 2 was administered with the feed in concentrations of 0, 1, 3, 10 and 30 ppm over a period of 3 months to groups of 2 male and female beagle dogs each. The appearance, behaviour, food consumption, growth and mortality of the treated dogs in all groups was not affected. In the groups up to 30 ppm cadmium caused no detectable harm to blood, liver or kidneys. The systolic and diastolic blood pressure of the treated animals of all groups up to 30 ppm was within the normal range. The autopsies and histopathological investigations revealed no evidence of any damage. Cadmium accumulated dose-dependently above all in the kidneys and liver. The dogs tolerated concentrations of up to 30 ppm cadmium in their feed over a period of 3 months without harm.

Biomedical responses of rats to chronic exposure to dietary cadmium fed in ad libitum and equalized regimes.

Forty 100 g male rats were fed, in groups of eight, either 0, 5, or 25 ppm cadmium in a purified diet for 14 wk. Three groups were fed each of the levels of cadmium on an ad libitum basis. Two other groups were fed either 0 or 5 ppm cadmium in amounts that were equalized to that consumed by the 25 ppm group fed ad libitum. Cadmium ingestion decreased daily diet consumption, weight gain, and terminal body weight. These parameters were not significantly different in rats whose diet consumption was equalized. Packed cell volume and serum iron as well as serum zinc were decreased in the rats fed 25 ppm cadmium. These effects were not related to diet intake. No major differences were observed in serum ceruloplasmin, glucose, protein, leucine aminopeptidase activity, or copper in any of the groups. Blood urea nitrogen and renal leucine aminopeptidase activity were decreased by cadmium ingestion in the rats fed ad libitum only. In contrast, serum alkaline phosphatase activity was elevated by cadmium in the equalized-intake groups only. Cadmium and zinc concentrations were elevated and the iron concentration was decreased in the kidney, liver, and intestinal mucosa of the cadmium-fed rats irrespective of level of diet consumption. The increased uptake of cadmium in these tissues was coincident with the increased content of the cadmium-binding protein, metallothionein, in the cytosol fraction. The results indicate that some parameters of chronic cadmium toxicity are associated with diet consumption whereas others are not.

Elevated systolic pressure following chronic low-level cadmiun feeding.

Groups of 16 female Long-Evans rats received 0, 1, 2.5, 5, 10, 25, and 50 mg cadmium/liter dringking water (parts per million (ppm)), from the time they were weaned until they were 30 mo old. Systolic pressure was measured indirectly in triplicate at 6-mo intervals. Both 2.5 and 5 ppm cadmium consistently induced significant elevations in mean systolic pressure, ranging from 13 to 33 mmHg. At 6 mo, 10 and 25 ppm cadmium also induced significant elevations, whereas at 12 mo and subsequently 1 ppm cadmium induced significant elevations. With 10 ppm cadmium or less weight gain was normal and there was no evidence of cadmium toxicity. With 25 and 50 ppm cadmium weight gain was diminished, suggesting toxicity. Five rats with each level of exposure were sacrificed every 6 mo from a second population of similarly handled rats in order to determine renal cadmium concetrations. Cadmium intakes that had induced hypertension were associated with mean renal cadmium concentrations ranging from 5 to 50 mug/g kidney.