Copper, manganese, zinc, nickel, cadmium and lead in human foetal tissues

1. Concentrations of copper, manganese, zinc, nickel, cadmium and lead were measured in samples of liver, kidney, brain, heart, lung, skeletal muscle and vertebral bone from forty foetuses of 23-43 weeks gestation. 2. Cu concentrations in the liver were up to 100 times those in other tissues, but only those in the brain showed a significant increase with gestational age. 3. Mn concentrations were similar in all tissues; the over-all range was 0.35-9.27 microgram/g dry matter (DM). 4. Concentrations of Zn in the liver were much higher than in other tissues and decreased with gestational age, whereas levels in skeletal muscle increased. 5. In all tissues Ni concentrations were within the range 0.04-2.8 microgram/g DM and levels in kidney and muscle decreased significantly with age. 6. Cd was detected in most of the tissue samples and concentrations were within the range 0.01-0.58 microgram/g DM. 7. Concentrations of Pb, where it was detected, varied from 0.1 to 2.4 microgram/g DM in the soft tissues and from 0.4 to 4.3 microgram/g DM in the bone samples.     

Distribution of cadmium in blood and tissues of wild birds

The principal aim of this study is to establish the kinetic behavior of cadmium by determining the concentrations of this element in the blood and in different tissues of wild birds exposed to environmental cadmium. We have studied a total of 118 birds living in the southeast of Spain, a zone with a Mediterranean climate and stopover point for important migratory species. The distribution pattern followed by the cadmium in our samples reveals that the kidney is the primary organ for accumulation, followed by the liver and, to lesser extent, the brain and bone. Low concentrations were found in the tissues and in the blood. The study of correlations between the different tissues and blood suggests a compartmental behavior of cadmium under these exposure conditions.     

Comparative toxicity of cadmium, zinc, and mixtures of cadmium and zinc to daphnids

Investigations were conducted to determine acute (48-h) effects of cadmium and zinc presented individually and in combination on Ceriodaphnia dubia, Daphnia magna, Daphnia ambigua, and Daphnia pulex. Toxicity tests were conducted with single metals to determine lethal effects concentrations (lethal concentrations predicted for a given percent [x] of a population, LCx value). These were used to derive metal combinations that spanned a range of effects and included mixtures of LC15, LC50, and LC85 values calculated for each metal and species. In single-metal tests, 48-h LC50 values ranged from 0.09 to 0.9 micromol/L and 4 to 12.54 micromol/L for cadmium and zinc, respectively. For each metal, D. magna was most tolerant and showed a different pattern of response from all others as determined by slope of concentration-response curves. In the combined metal treatments, all daphnids showed a similar pattern of response when LC15 concentrations were combined. This trend continued with few exceptions when LC15 concentrations of cadmium were combined with LC50 or LC85 values for zinc. However, when this treatment was reversed (LC15, zinc + LC50 or LC85, cadmium), responses of all species except D. magna indicated less-than-additive effects. For C. dubia, a near complete reduction in toxicity was observed when the LC15 for zinc was combined with LC85 for cadmium. Multimetal tests with D. magna did not differ from additive. Collectively, these studies suggest that D. magna may not be representative of other cladocerans.     

Cadmium contamination of tissues and organs of delphinids species (Stenella attenuata)--influence of biological and ecological factors

Based on a sample of 27 dolphins (Stenella attenuata) captured in the Eastern tropical zone of the Pacific Ocean, this study was carried out to analyze the cadmium accumulation levels and distribution in 12 organs or tissue samples. The average cadmium concentrations were between 0.2 mg Cd.kg-1 in the brain and muscle and 48 mg Cd.kg-1 in the kidneys. For most of organs and tissues the average values were between 1 and 5 mg Cd.kg-1. Kidneys, liver, muscle, and intestine contained almost 85% of the total cadmium burden of all tissues considered in this study. Most of the biological and ecological factors taken into account (age, sex, total weight, and length of the dolphins, weight of the organs, place and date of capture) interacted with the cadmium concentrations and burdens in the collected organs or tissues. Three factors appear to be of prime importance: age, body weight, and geographical location of the area of capture.     

Organochlorine residues in tissues of striped dolphins affected by the 1990 mediterranean epizootic: Relationships with the fatty acid composition

A simple and rapid method was developed for the simultaneous determination of fatty acids, organochlorine pesticides, and polychlorinated biphenyl (PCB) congeners in the same sample in order to explore possible connections between levels of contaminants and fatty acid composition. The method was applied to samples of melon, cerebrum, cerebellum, lung, liver, kidneys, and skeletal muscle obtained from 5 male and 5 female striped dolphins (Stenella coeruleoalba) found stranded in 1990 in the northeastern Spanish coasts during the morbillivirus epizootic that affected this cetacean in the Mediterranean Sea. The results indicate that PCBs were dominant in all tissues, with the highest geometric mean concentration being found in melon (903 g g^–1 wet wt); DDTs were also found at high concentrations (111 g g^–1 wet wt, in melon). Statistical analysis indicate that organochlorine concentration was correlated with the fatty acid composition of tissues, although some of these variations can be interpreted as a consequence of a shift in the diet produced in the striped dolphin population. However, other changes such as the negative correlation with arachidonic acid may suggest that the eicosanoid production could have been affected by the extremely high concentrations of PCBs and DDTs.     

Distribution and retention of cadmium109 by the gastrointestinal tract and other organs following intraperitoneal cadmium exposure

Bulletin of Environmental Contamination and Toxicology -     

Acute toxicity of cadmium, lead, zinc, and their mixtures to stream-resident fish and invertebrates

The authors conducted 150 tests of the acute toxicity of resident fish and invertebrates to Cd, Pb, and Zn, separately and in mixtures, in waters from the South Fork Coeur d'Alene River watershed, Idaho, USA. Field-collected shorthead sculpin (Cottus confusus), westslope cutthroat trout (Oncorhynchus clarkii lewisi), two mayflies (Baetis tricaudatus and Rhithrogena sp.), a stonefly (Sweltsa sp.), a caddisfly (Arctopsyche sp.), a snail (Gyraulus sp.), and hatchery rainbow trout (Oncorhynchus mykiss), were tested with all three metals. With Pb, the mayflies (Drunella sp., Epeorus sp., and Leptophlebiidae), a Simuliidae black fly, a Chironomidae midge, a Tipula sp. crane fly, a Dytiscidae beetle, and another snail (Physa sp.), were also tested. Adult westslope cutthroat trout were captured to establish a broodstock to provide fry of known ages for testing. With Cd, the range of 96-h median effect concentrations (EC50s) was 0.4 to >5,329 μg/L, and the relative resistances of taxa were westslope cutthroat trout ≈ rainbow trout ≈ sculpin < other taxa; with Pb, EC50s ranged from 47 to 3,323 μg/L, with westslope cutthroat trout < rainbow trout < other taxa; and with Zn, EC50s ranged from 21 to 3,704 μg/L, with rainbow trout < westslope cutthroat trout ≈ sculpin < other taxa. With swim-up trout fry, a pattern of decreasing resistance with increasing fish size was observed. In metal mixtures, the toxicities of the three metals were less than additive on a concentration-addition basis.     

Urinary excretion of cadmium, copper and zinc in workers exposed to cadmium

Changes in urinary cadmium, copper and zinc excretion in workers who had considerable exposure to cadmium oxide fumes were investigated over a 5-year period following the cessation of exposure. The 22 male subjects aged 22 to 55 had been welders on automobile parts for periods ranging from 7 months to 23 years, using silver solder which contained cadmium. They were divided into three groups according to levels of urinary cadmium in the first medical examination in 1975: 5 in the high excretion group, 11 in the moderate group, and 6 in the low group. Renal tubular dysfunctions were indicated in most workers in the high excretion group but not in the other two groups. The high and moderate groups showed a rapid decrease in the levels of urinary-excreted cadmium, with biological half-times of 1.42 and 1.21 years, respectively. Excreted cadmium levelled off in the two groups about 1.7 and 1.5 years after the last exposure. Urinary copper excretion in the high cadmium excretion group was about twice that in the moderate and low groups, the difference being statistically significant in comparison with the controls. Urinary zinc excretion was high in all subjects immediately after cessation of exposure but decreased rapidly. After three years it was found that the reduction of urinary zinc was greatest in the high cadmium group. Urinary cadmium showed significant correlations with both copper and zinc. Urinary copper showed a negative correlation with zinc excretion in the high cadmium excretion group and a significant positive correlation in the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Accumulation of cadmium in organs of mice by a long-term injection of cadmium and interactions of cadmium with copper, manganese and zinc already present in the animals (author's transl)]

It is well known that the greater part of the administered cadmium is accumulated in liver and kidneys. But, in considering the toxicity of cadmium, it is important to make clear the time pattern of cadmium accumulation not only in liver and kidneys but in the other organs. Male mice were injected subcutaneously 1 mg/kg of cadmium daily for 25 weeks except one day in every week. Five mice at a time were killed in the suitable time during this experiment, and Cd, Cu, Mn, and Zn concentrations in several organs were determined by atomic absorption spectrophotometry. Cadmium content in liver and kidneys increased remarkably during the first 30 days, and it is scarcely increased after that period. Cadmium content in other organs, that is, heart, lungs, spleen, testes and femurs, increased slowly during the first 20 days, and this content increased hardly after that. The results show further that: Cd administered at the early stage accumulated mainly in liver an in kidneys. As Cd concentration in liver and kidneys arrives at saturation, Cd content in other orbans increased remarkably. And, after 30th day, Cd content in all the organs increased little in spite of the continuous injection of Cd. Concentrations of Cu, Mn, and Zn in the organs of mice injected with Cd were as follows: Cu concentration increased significantly in heart, liver, and kidneys, Zn concentration increased in heart, lungs, liver, and kidneys, whereas Mn concentration decreased remarkably in kidneys. Cadmium content in the organs of mice injected with Zn (0.5 mg/kg) or Mn (0.5 mg/kg) together with Cd (1 mg/kg) showed a tendency to increase remarkably compared with single injection of Cd.     

Marginal nutritional status of zinc, iron, and calcium increases cadmium retention in the duodenum and other organs of rats fed rice-based diets

Dietary minerals Zn, Fe, and Ca are antagonistic to Cd absorption. We showed earlier that rats fed a rice-based diet with a marginal content of these nutrients absorbed more Cd than rats fed adequate Zn-Fe-Ca (Environ. Sci. Technol., 36 (2002) 2684-2692). The present experiment was designed to determine the effects of marginal dietary Zn, Fe, and Ca on the uptake and turnover of Cd in the gastrointestinal tract. Two groups of weanling female rats (six per treatment) were fed a diet containing 40% cooked, dried rice containing 0.6 mg Cd/kg. The diet of one group contained adequate Zn (35 mg/kg), Fe (30 mg/kg), and Ca (5000 mg/kg), while that of the other group contained marginal Zn (6 mg/kg), Fe (9 mg/kg), and Ca (2500 mg/kg). Rats were fed for 5 weeks and then orally dosed with 1g of diet containing rice extrinsically labeled with 109Cd. From 0.25 to 64 days after dosing, 109Cd and total Cd concentrations were determined in intestinal segments. Shortly after dosing, 109Cd, as a percentage of the dose, was about 4 times higher in the duodenum of marginally fed rats than in that of control rats (10% vs 40%, respectively). Sixty-four days after dosing, 109Cd was 10 times higher in marginally fed rats than in controls; however, of the amount at day 1, <0.1% remained at day 64. After 5 weeks, the concentration of elemental Cd in the duodenum of the marginally fed rats was 8 times higher than that of control rats (24 microg/g dry wt. vs 2.9 microg/g dry wt., respectively). Cd concentrations in liver and kidney were 5 times higher in the marginally fed rats than those in controls (liver, 0.81 microg/g dry wt. vs 0.14 microg/g dry wt.; kidney, 4.7 microg/g dry wt. vs 0.92 microg/g dry wt., respectively). These data suggest that marginal intakes of Zn, Fe, and Ca cause the accumulation of Cd in the duodenum, which results in a greater rate of Cd absorption and a greater accumulation in the internal organs. Results are discussed in relation to mineral nutrient status and risk assessment of Cd in natural food sources.     

The influence of cadmium and zinc on cadmium turnover in the zebrafish,Brachydanio rerio

A study was made of the dynamics of non-dietary cadmium in fish exposed to different concentrations of cadmium and zinc in water. Zebrafish,Brachydanio rerio, were exposed to Cd and Zn for various periods. The fate of a short pulse of the radioactive tracer¹⁰⁹Cd (3 or 9 days) was studied during a post-pulse period of 53 or 83 days. The tracer elimination and accumulation were described by exponential equations. The constants obtained from regression analysis of the results were used as a tool for evaluation of the findings.The majority of the¹⁰⁹Cd taken up in the gills during the pulse period was retained in the gill tissue and slowly transferred to the internal organs or lost to the water during the post-pulse period. The retention of tracer in the gills after a 3-day¹⁰⁹Cd pulse was increased by Zn but not influenced by Cd. Continuous exposure to stable Cd increased the rate of turnover of the retained¹⁰⁹Cd. Both Cd and Zn increased the tracer accumulation in the liver and kidney. The results also indicated that the effect of Zn on the Cd turnover might be lost if the environmental Zn is withdrawn before the start of the¹⁰⁹Cd pulse.A tendency of increased mortality of the fish exposed to 1 g Cd/L for 2–3 months suggested that low concentrations of Cd is toxic to the fish during chronic exposure. The increased Cd uptake and transfer in the gills, caused by Zn, could have deleterious effects on the fish. It might also reflect a change in the form of transport and in the intracellular handling of the metal, which protects the fish from Cd toxicity. However, a Zn pre-exposure did not decrease the mortality, which suggests that Zn did not protect the fish from Cd toxicity.     

Interactions of cadmium and zinc impact their toxicity to the earthworm Aporrectodea caliginosa

Individual and binary mixture effects of Cd and Zn on mortality of the earthworm Aporrectodea caliginosa were investigated in one soil type. Mutual, systemic interactions of Cd and Zn were assessed over a broad range of concentration combinations. Exposures were expressed as measured total concentrations in soil, porewater concentrations, and CaCl(2)-extractable concentrations. The Cd-Zn and Zn-Cd interactions in soil were estimated by comparing partition coefficients (K(d)) of one metal in the presence and absence of the second metal. Simple patterns of mixture toxicity (additive, antagonistic, or synergistic) were evaluated by the toxic unit approach. The more complex patterns (dose ratio dependent or dose level dependent) were quantified by the MIXTOX model. The partitioning of Cd and Zn between soil and pore water was affected neither by their concentration nor presence of the other metal, and metal partitioning remained linear at all exposure levels tested. The effect of the Cd and Zn mixtures on mortality of A. caliginosa was mainly antagonistic, and the magnitude of antagonism (1.1- 2.7 toxic units) was dependent upon both the relative concentrations of Cd and Zn and the concentration magnitudes. Interactions of both metals occurred at the organism level and were manifested in terms of effects (28-d median lethal concentrations). The present study highlights the importance of identifying the relative influence of various interactions from external exposure to internal assimilation in evaluating mixture toxicity.