Lead Concentrations In Kidney Research Articles

Effects of Bacterial Cellulose Nanofiber on Lead Concentration in Kidney and Liver Tissues of Wistar Rats

Effects of Bacterial Cellulose Nanofiber on Lead Concentration in Kidney and Liver Tissues of Wistar Rats

Trace metals from historical mining sites and past metallurgical activity remain bioavailable to wildlife today

Throughout history, ancient human societies exploited mineral resources all over the world, even in areas that are now protected and considered to be relatively pristine. Here, we show that past mining still has an impact on wildlife in some French protected areas. We measured cadmium, copper, lead, and zinc concentrations in topsoils and wood mouse kidneys from sites located in the Cévennes and the Morvan. The maximum levels of metals in these topsoils are one or two orders of magnitude greater than their commonly reported mean values in European topsoils. The transfer to biota was effective, as the lead concentration (and to a lesser extent, cadmium) in wood mouse kidneys increased with soil concentration, unlike copper and zinc, providing direct evidence that lead emitted in the environment several centuries ago is still bioavailable to free-ranging mammals. The negative correlation between kidney lead concentration and animal body condition suggests that historical mining activity may continue to play a role in the complex relationships between trace metal pollution and body indices. Ancient mining sites could therefore be used to assess the long-term fate of trace metals in soils and the subsequent risks to human health and the environment.

Distribution of lead in selected organs and its effect on reproduction parameters of pheasants (Phasianus colchicus) after an experimental per oral administration

Lead poisoning has been reported in almost every country on earth. In this study the effect of experimental lead pellet intake (2–6 pellets per week [groups B2, B4, B6] and ad libitum [BAD] accessibility for 10 weeks) on its distribution in liver, kidney, pectoral muscle, ovary, eggs and the effect of selected reproductive parameters (egg weight, fertilization, hatchability) was analyzed in breeding pheasants. Lead pellets were force fed to the digestive tract (struma, ingluvies) and the ingestion was controlled. Concentration of lead was detected using the atomic absorption spectrophotometry. Analysis of the lead concentration in liver showed a significantly higher concentration in all group after the lead pellets intake. The increase of the lead concentration was dose–dependent and the concentration detected in group BAD was similar as in group B2. Very similar tendencies were detected for the lead concentration in kidney. The accumulation of lead in pectoral muscle was lower, in comparison with liver and kidney. Compared to lead concentration detected in ovary of the control group a significant increase was detected in all experimental groups, reaching the maximum in the group B6. Similar significant increase of lead concentration was detected in eggs. The average weight of eggs was 32.01 ± 2.71 g in the control group and lower in all experimental groups, but this decrease was significant only in the group B6. The fertilization rate was the highest in the control group and a dose–dependent decrease was detected with the lowest value in the group B6. For egg hatching ratio a significant decrease was detected in groups B4 and B6. Results of this study clearly describe accumulation of lead in the body and a its negative effect on the reproductive parameters. In the ad libitum experimental group the most similar results were found as in group B2, suggesting a rate of “natural” lead pellet intake.

A comparison of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning

Introduction. This article reviews the experimental and clinical studies that have compared the efficacy (impact on urine lead excretion, blood and tissue lead concentrations, resolution of features and survival) of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning. It also summarizes the pharmacokinetic and pharmacodynamic aspects and the adverse effects of treatment. Methods. Medline, Toxline, and Embase were searched for all available years to June 2009. Pharmacokinetics and pharmacodynamics. The absorption of oral DMSA is more complete than sodium calcium edetate; the latter has to be administered parenterally. Both antidotes are distributed predominantly extracellularly. Sodium calcium edetate is not metabolized, whereas DMSA is extensively metabolized to mixed disulfides of cysteine. The two antidotes have elimination half-lives of less than 60 min. There is no evidence that either antidote crosses the blood–brain barrier to any major extent. Sodium calcium edetate chelates lead by displacement of the central Ca2+ ion with Pb2+. The nature of the DMSA–lead chelate is less clearly defined. There is evidence that the mixed disulfides of cysteine are the active chelating moiety in humans. If this is the case, this suggests that chelation occurs principally, if not exclusively, in the kidney. The primary source of lead mobilized by sodium calcium edetate is bone with an additional contribution from kidney and liver. Efficacy. Comparison of the experimental studies is complicated by substantial variations in study design, particularly the antidote dose, the route and duration of treatment, the amount and duration of lead dosing, and lack of direct comparison between antidotes (comparison was usually made with control). In experimental studies that used equimolar and clinically relevant antidote doses and assessed the impact of DMSA and sodium calcium edetate on urine lead excretion and/or blood lead concentrations, similar results were found, though no direct comparison between antidotes was undertaken. DMSA was more effective than sodium calcium edetate in reducing the kidney lead concentration, sodium calcium edetate was more effective than DMSA in reducing bone lead concentrations, and there was no consistently observed effect of chelation therapy on brain lead concentrations in these experimental studies. Only two clinical studies have compared equimolar or similar antidote doses in enhancing urine lead excretion; there was no statistical difference between the antidotes, though both studies had limitations. DMSA and sodium calcium edetate had a comparable impact on lowering blood lead concentrations in a clinical study using similar molar antidote doses. Adverse effects. Sodium calcium edetate causes dose-related nephrotoxicity. Both agents deplete zinc and copper, the effect on zinc being significantly greater with sodium calcium edetate. A transient increase in hepatic transaminase activity has been reported with both antidotes but appears to be more common with DMSA and neither has been associated with clinically significant hepatic toxicity. Skin lesions during treatment with sodium calcium edetate are unusual and have been attributed to zinc deficiency. DMSA has occasionally been associated with a severe mucocutaneous reaction necessitating discontinuation of therapy. Conclusions. Oral DMSA and parenteral sodium calcium edetate are both effective chelators of lead. There are currently insufficient data, however, to conclude that either antidote is superior in enhancing lead excretion. Both antidotes resolve the symptoms of moderate and severe lead toxicity rapidly. Although there is greater clinical experience with sodium calcium edetate, particularly in the treatment of lead encephalopathy, oral DMSA may now be considered as an alternative in circumstances where oral therapy is preferable.

The European maximum level for cadmium in bovine kidneys is in Belgium only realistic for cattle up to 2 years of age

The effect of animal age on concentrations of cadmium, lead, arsenic, copper and zinc in bovine tissues (meat, kidney and liver) sampled from animals reared in contaminated areas or reference regions in Belgium was investigated. For cadmium concentrations in meat samples analysis of variance (ANOVA) showed an increasing trend with age. In addition, a significant positive linear relation (p < 0.05) was found between animal age and renal (R 2 = 0.56) or hepatic (R 2 = 0.39) cadmium levels. Lead concentrations in kidneys and liver also increased with age, but the effect was blurred, likely due to the internal remobilization of lead. For the other trace elements (arsenic, copper, zinc) no relationship could be found between their concentration in meat, kidneys or liver and animal age. Renal cadmium concentrations were predicted for bovines at different ages by using the slope of the linear regression equation, and by taking into account its 95% confidence interval. Calculations for 2-year-old animals from reference areas showed that in this group the European maximum level of 1 mg kg−1 for cadmium in kidneys would be exceeded in zero to 5% of cases. If a general rejection percentage of maximum 5% would be desirable for kidneys sampled in the reference areas (according to the ALARA principle–‘as low as reasonably achievable’–of European Union policy), then (1) kidneys from animals older than 2 years from the reference areas should a priori not be considered suitable to be placed on the market, or (2) the maximum level for cadmium in kidneys should be increased to 3 mg kg−1. The latter would bear negligible risks for the general population and the majority of high-level kidney consumers. On the other hand, bovine kidneys from the most contaminated areas are not suitable to be brought into the food chain because it is predicted that the maximum level is already exceeded by more than 5% of the 1-year-old animals.

Effects of lead intoxication on intercellular junctions and biochemical alterations of the renal proximal tubule cells

Lead intoxication is a worldwide health problem which frequently affects the kidney. In this work, we studied the effects of chronic lead intoxication (500 ppm of Pb in drinking water during seven months) on the structure, function and biochemical properties of rat proximal tubule cells. Lead-exposed animals showed increased lead concentration in kidney, reduction of calcium and amino acids uptake, oxidative damage and glucosuria, proteinuria, hematuria and reduced urinary pH. These biochemical and physiological alterations were related to striking morphological modifications in the structure of tubule epithelial cells and in the morphology of their mitochondria, nuclei, lysosomes, basal and apical membranes. Interestingly, in addition to the nuclei, inclusion bodies were found in the cytoplasm and in mitochondria. The epithelial cell structure modifications included an early loss of the apical microvillae, followed by a decrement of the luminal space and the respective apposition and proximity of apical membranes, resulting in the formation of atypical intercellular contacts and adhesion structures. Similar but less marked alterations were observed in subacute lead intoxication as well. Our work contributes in the understanding of the physiopathology of lead intoxication on the structure of renal tubular epithelial cell–cell contacts in vivo.

The combined effect of lead exposure and high or low dietary calcium on health and immunocompetence in the zebra finch ( Taeniopygia guttata)

The widespread contamination by lead and the acidification of the environment ask for a better understanding of the effects of the interaction between lead and calcium on various aspects of health, including disease defense, in wildlife. Here, we investigated the effects of chronic exposure to sublethal levels of lead, combined with high or low dietary calcium, on health and several components of immunity in male and female zebra finches ( Taeniopygia guttata). Thirty individuals of each sex were randomly assigned to three groups: a control group, a group exposed to lead with an additional calcium source (i.e. grit) and a group exposed to lead without access to an extra calcium source. Lead was administered as lead acetate via the drinking water (20 ppm) for 38 consecutive days. Exposure to lead increased significantly the concentrations of lead in kidney and bone in individuals of the experimental groups. Furthermore, the lack of a calcium supplement significantly enhanced the uptake of lead. Lead did not affect health indices such as hematocrit, spleen mass and body mass, nor the adrenal stress response. Cell-mediated immune responsiveness, assessed by a delayed-type hypersensitivity response to phytohaemagglutinin, was also not affected by lead exposure. On the other hand, lead exposure did significantly suppress the secondary humoral immune response towards sheep red blood cells in females, but only when the additional calcium source was not available. This effect was not found in males, suggesting sexual differences in susceptibility of humoral immunity to lead treatment in zebra finches.

DEVELOPMENTAL TOXICITY OF LEAD-CONTAMINATED SEDIMENT IN CANADA GEESE (Branta canadensis)

Sediment ingestion has recently been identified as an important exposure route for toxicants in waterfowl. The effects of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho on posthatching development of Canada geese (Branta canadensis) were examined for 6 wk. Day-old goslings received either untreated control diet, clean sediment (48%) supplemented control diet, or CDARB sediment (3449 mug/g lead) supplemented diets at 12%, 24%, or 48%. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 0.68 ppm (ww), with over 90% depression of red blood cell ALAD activity and over fourfold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 1.61 ppm with decreased hematocrit, hemoglobin, and plasma protein in addition to the effects just described. The 48% CDARB diet resulted in blood lead of 2.52 ppm with 22% mortality, decreased growth, and elevated plasma lactate dehydrogenase-L (LDH-L) activity. In this group the liver lead concentration was 6.57 ppm (ww), with twofold increases in hepatic lipid peroxidation (thiobarbituric acid-reactive substances, TBARS) and in reduced glutathione concentration; associated effects included elevated glutathione reductase activity but lower protein-bound thiols concentration and glucose-6-phosphate dehydrogenase (G-6-PDH) activity. The kidney lead concentration in this group was 14.93 ppm with subacute renal tubular nephrosis in one of the surviving goslings. Three other geese in this treatment group exhibited calcified areas of marrow, and one of these displayed severe chronic fibrosing pancreatitis. Lead from CDARB sediment accumulated less readily in gosling blood and tissues than reported in ducklings but at given concentrations was generally more toxic to goslings. Many of these effects were similar to those reported in wild geese and mallards within the Coeur d'Alene River Basin.

Developmental toxicity of lead-contaminated sediment to mallard ducklings.

Sediment ingestion has been identified as an important exposure route for toxicants in waterfowl. The toxicity of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho was examined on posthatching development of mallard (Anas platyrhynchos) ducklings for 6 weeks. Day-old ducklings received either untreated control diet, clean sediment (24%) supplemented control diet, CDARB sediment (3,449 microg/g lead) supplemented diets at 12% or 24%, or a positive control diet containing lead acetate equivalent to that found in 24% CDARB. The 12% CDARB diet resulted in a geometric mean blood lead concentration of 1.41 ppm (WW) with over 90% depression of red blood cell ALAD activity and over threefold elevation of free erythrocyte protoporphyrin concentration. The 24% CDARB diet resulted in blood lead of 2.56 ppm with over sixfold elevation of protoporphyrin and lower brain weight. In this group the liver lead concentration was 7.92 ppm (WW), and there was a 40% increase in hepatic reduced glutathione concentration. The kidney lead concentration in this group was 7.97 ppm, and acid-fast inclusion bodies were present in the kidneys of four of nine ducklings. The lead acetate positive control group was more adversely affected in most respects than the 24% CDARB group. With a less optimal diet (mixture of two thirds corn and one third standard diet), CDARB sediment was more toxic; blood lead levels were higher, body growth and liver biochemistry (TBARS) were more affected, and prevalence of acid-fast inclusion bodies increased. Lead from CDARB sediment accumulated more readily in duckling blood and liver than reported in goslings, but at given concentrations was generally less toxic to ducklings. Many of these effects are similar to ones reported in wild mallards and geese within the CDARB.

Lead in Tissues of Deseased Lead Smelter Workers

Smelter workers are exposed to a number of metals and other substances in dust, fumes and gases. The concentrations of lead in liver, lung, kidney, brain, hair and nails were determined in 32 deceased, long-term exposed male lead smelter workers, and compared with those of 10 male controls. The lead levels in liver, lung, kidney and brain were analyzed by atomic absorption spectrophotometry. X-ray fluorescence was used for the determinations in hair and nails. Lead in blood had been determined repeatedly in the lead workers since 1950, which made it possible to calculate a time-integrated blood lead index for each worker. The highest lead levels in soft tissues were found in liver, followed in order of concentration by kidney, lung and brain, among both exposed workers and controls. These organ lead concentrations were all significantly higher among the workers as compared with the control group (p < or = 0.02). The largest difference between workers and controls was found in brain tissue (ratio between median values = 5.6). The lead levels in hair and nails were of the same magnitude in the two groups. The workers showed positive correlations between lead concentrations in liver and kidney (Spearman's rho = rs = 0.59; p < 0.001), liver and hair (rs = 0.51; p = 0.003), liver and nails (rs = 0.52; p = 0.002) and hair and nails (rs = 0.52; p = 0.002). Lead concentrations in kidney correlated well with lead levels in hair (rs = 0.57; p = 0.001) and nails (rs = 0.51; p = 0.003), respectively. The positive correlation between the lead concentrations in liver and kidney indicates that these organs belong to the same soft tissue lead pool in the body. In retired lead workers, positive correlations were observed between the lead concentrations in liver and the cumulative blood lead index (CBLI) (rs = 0.50; p = 0.016), as well as between lead levels in kidney and CBLI (rs = 0.51; p = 0.014).

Mobilization of lead in mice by administration of monoalkyl esters of meso-2,3-dimercaptosuccinic acid

The following six monoalkyl esters of meso-2,3-dimercaptosuccinic acid (DMSA) were synthesized and evaluated for relative activities in mobilizing lead from kidneys and brains of lead-bearing mice: n-propyl (M n-PDMS), i-propyl (M i-PDMS), n-butyl (M i-BDMS), n-amyl (M n-ADMS) and i-amyl meso-2,3-dimercaptosuccinate (M i-ADMS). DMSA was used as a positive control. When each was administered intraperitoneally (i.p.) as a single dose of 2.0 mmol/kg, DMSA lowered the kidney lead concentration 52%, while the monoesters effected reductions of 54–75%. M n-ADMS was toxic at this dose. DMSA lowered the brain lead level 20% when given as a single dose, while the monoesters conferred reductions of 64–87%. When given as 5 daily i.p. injections at 0.5 mmol/kg, DMSA reduced the kidney lead concentration 45%, while the monoesters caused reductions of 56–73%. DMSA lowered the brain lead concentration 35% on the 5-day treatment regimen, while the monoesters evoked reductions of 59–75%. M i-ADMS was equally effective when given orally or i.p. The i.p. LD 50 value of this analog in mice is 3.0 mmol/kg, a value which lies between the reported LD 50 doses of DMSA (16.0 mmol/kg) and dimercaprol (1.1 mmol/kg). It is suggested that the ability of these monoesters to cross cell membranes may account for their superiority to DMSA in mobilizing brain lead in this animal model.

Stable isotope labeling of lead compartments in rats with ultralow lead concentrations

The role of the mammalian skeleton as an endogenous lead source is unclear. This is due in part to difficulties in distinguishing mobilized skeletal lead from other endogenous and exogenous lead sources. Therefore, we have applied ultraclean stable lead isotope techniques to label skeletal and soft tissue lead compartments within the rat with distinguishable lead isotopic signatures. Female Wistar (defined flora) rats were fed 206Pb-enriched drinking water ([Pb] = 110 ng/ml) and sacrificed after durations of 2, 4, 7, and 14 days. Blood, kidney, vertebra, and tibia tissues were analyzed for lead concentrations and stable isotopic compositions. The resulting isotopic ratios in soft (blood and kidney) and skeletal (vertebrae and tibia) tissues differed by approximately 40% after 2 days exposure to the 206Pb tracer. More than 90% of the tracer isotopic signature was contained in the soft tissues after 10 days exposure, while skeletal tissues acquired only approximately 50% of the tracer by the end of the study. Because these animals were maintained under trace metal-clean conditions, they contained lead concentrations in whole blood (0.3-3 ng/g), kidney (11-27 ng/g dry wt), and bone (35-70 ng/g dry wt) tissues that are the lowest known reported for contemporary terrestrial mammals, and they (in bone) are comparable to levels in preindustrial mammals. The elevated concentrations of lead in kidney (fresh weight) relative to levels in blood are consistent with the presence of specific lead-binding sites in the kidney at very low levels of exposure.

Battery lead recycling and environmental pollution hazards

In Italy, lead recycling from discarded electric storage batteries has been developing on an industrial scale, with a yield of approximately 98% and a saving of 37% on lead imports. Moreover, battery plastic coverings can also be profitably recycled. However, the recovery industry has proved to be very polluting, as shown by the recent example of a factory sited in a vast agricultural area south of Milan, Italy. Lead in the atmosphere affects workers exposed to lead concentrations above A.C.G.I.H. standards, while lead in wastewaters and fumes from smelting furnaces is the cause of environmental pollution. In particular, pollution over large tracts of cultivated lands surrounding such factories is shown by the considerable quantity of lead in forage (typically, 411 mg/kg in hay, 365 mg/kg in maize) which is harmful to cattle fed on it. Tests on dead oxen have revealed lead concentrations in kidneys and liver ranging from 9.1 to 17.4 mg/kg and 6 to 7 mg/kg respectively. Quantities exceeding safety limits have been found also in cattle blood and milk, with maximum values of 51 μg/100 ml and 0.072 mg/l respectively. The results of the present research, which is still going on after the adoption of antipollution measures, prove the need for extremely efficient control systems in this particular recovery industry.

Toxicity of Iceland lichen and reindeer lichen.

Iceland lichen (Cetraria islandica) is sold in health food stores to prevent various disorders. In olden times it and sometimes also reindeer lichen (Cladonia sp.) have been used as emergency food. Lichen contains bitter and potentially toxic lichen acids and it also concentrates heavy metals. Therefore lichen toxicity was studied with traditional pretreatment methods (boiling, ash-soaking or both). Untreated and only shortly boiled lichens were lethally toxic to mice in 50 and 25% w/w mixtures in food, but when ash-soaking was added mice tolerated Cetraria (but not Cladonia) reasonably well for 3 weeks. In a 3 month test in rats 25% mixture of Cladonia was tolerated well and blood tests were normal at the end. However, urinary protein was increased, the autopsies revealed kidney changes corresponding to a mild heavy metal poisoning, as the lead concentrations in kidney and lichen were high.

Histologic and Ultrastructural Lesions of Mourning Doves (Zenaida macroura) Poisoned by Lead Shot

Studies were conducted in which mourning doves (Zenaida macroura) were administered lead shot, and their tissues were examined by histology and their kidneys were examined by electron microscopy. Doves that ingested four number 8 lead shot and were sacrificed 4 days later had highly elevated lead concentrations in kidney and had acid-fast intranuclear and acid-fast intracytoplasmic inclusions in the cells of the proximal convoluted tubules. Hemosiderin loading was present in the liver as was elevated concentrations of lead in liver. Doves that ingested either four or eight number 8 lead shot and were sacrificed 9 days later had elevated lead concentrations in liver, and hemosiderin loading was present. Acid-fast intranuclear inclusions were present in the proximal convoluted tubule cells. Kidney lead was highly elevated and cellular degeneration was evident with electron microscopic examination.

A Comparative Study of Lead Nephrotoxicity and Tissue Deposition Between Rats, Mice, and Pigeons Exposed to Drinking Water Containing 2, 20, or 200 ppm Lead

White Carnaew pigeons were exposed to drinking water containing various concentrations of lead to study the relationship between exposure and tissue deposition and the relationship between the concentrations of lead in kidney and morphologic alterations. The concentration of lead in the blood was the only tissue which showed a linear increase with respect to the concentration of lead in the drinking water. The concentration of lead in the liver, kidney, brain, heart, aorta, and pancreas increased in response to lead in the drinking water; however, these increases were not linear with respect to lead exposure. Similar results were obtained for rats and mice exposed via the drinking water to 2, 20, or 200 ppm lead; however, the concentration of lead in tissues was substantially greater in pigeons. Kidneys from rats and mice appeared normal following the exposure of 200 ppm lead for 4 months, whereas, in kidneys from pigeons exposed to 200 ppm for a similar period of time there was tubular degeneration, fibrosis, and acid fast intranuclear inclusion bodies. These pathoanatomic alterations may be related to the concentration lead found in the kidney in pigeons. The concentration of lead in the kidney was 3,930 μg gram dry weight for pigeons but only 40 and 6 μg for mice and rats respectively. These studies suggest that the pigeon is more responsive to ingested lead than the rat or mouse. The renal lesions induced by chronic lead exposure are similar in pigeons and man suggesting that the pigeon may be useful animal model to study the yet unanswered questions related to chronic nephritis following lead poisoning.

Tissue concentrations of cadmium, lead and chromium in japanese ranging from the fetus to elder subjects

Concentrations of cadmium, lead and chromium in kidney, gonad and brain of dead Japanese were measured in this study. Cadmium concentrations of the fetal tissues were less than 0.083 μg/g tissue. Cadmium concentrations of liver and kidney were observed to be higher as the age of subjects increased, whereas there was no difference in the tissues of gonad and brain. The highest increment of cadmium with aging was measured in kidney. The amount of lead in the fetal liver was nearly equal to that of adult tissue. Lead concentrations in kidney and brain of the adult were higher than those of the fetus. The concentrations of chromium were less than 0.06 μg/g tissue in both the adult and fetal tissues.

Heavy Metal Residues in Plants Cultivated on and in Small Mammals Indigenous to Old Orchard Soils

Six vegetables and millet were grown on the site of an old orchard which had received heavy applications of lead arsenate and organic mercury fungicides for many years. Carrots and millet absorbed about 7 ppm (dry weight) of lead, the other crops containing smaller concentrations. Concentrations of arsenic and mercury showed only modest increases in crops grown on the orchard soil as compared to controls. Lead concentrations in kidney, liver, and bone tissue of meadow voles trapped in two old orchards were markedly higher (up to 300 ppm in bone) than control animals (up to 33 ppm). Intranuclear inclusion bodies diagnostic of lead poisoning were found in the renal epithelial cells of the proximal convoluted tubules in voles from lead arsenate treated orchards.

Influence of Dietary Copper on Lead Toxicity in the Young Male Rat

An investigation of the influence of dietary copper (1, 5, 20 ppm) on toxicity of dietary lead (0 and 200 ppm) in the young male rat in a 4-week period indicated that as dietary copper increase so did the severity of lead toxicity. Evidence included increased lead concentration in kidney and a two- to threefold increase in the excretion of urinary delta-aminolevulinic acid. Liver copper concentration was also found to increase in rats receiving lead at the two lower copper levels. The data suggest that supplementary dietary copper doesnot lessen the severity of lead toxicity but rather exaggerates it.