Comparison of in vivo effect of inorganic lead and cadmium on glutathione reductase system and delta-aminolevulinate dehydratase in human erythrocytes.

The activity of delta-aminolevulinate dehydratase (ALAD) of erythrocytes, the lead (Pb-B) and cadmium (Cd-B) concentration in whole blood, the content of reduced glutathion (GSH) in erythrocytes, and the regeneration rate of GSH by intact erythrocytes were measured during an epidemiological survey of 84 men employed in a Belgian cadmium and lead producing plant. A control group of 26 persons (students and laboratory staff) was also examined. The logarithm of the ALAD activity is highly inversely correlated with log Pb-B (r = -0.760) but no correlation was found with log Cd-B. There exists a significant negative correlation between GSH and log Pb-B (r = -0.423) but not between GSH AND LOG Cd-B. The apparently good relationship between log ALAD and GSH disappeared completely by holding log Pb-B constant, but log ALAD remained highly inversely correlated with log Pb-B when standardized for GSH concentration (r = -0.748). In vivo investigation of the GSH regeneration rate of intact erythrocytes demonstrated clearly that the overall activity of the glutathione oxidation-reduction pathways is not impaired in Pb and Cd-exposed workers with significantly increased Pb-B and Cd-B, since their initial GSH regeneration rate (first 15 minutes) was identical with that of the control group. Results of similar in vitro experiments in which control whole blood was incubated before-hand with Pb2+ or Cd2+, or both, reinforce this conclusion. Since increased Cd-B and Pb-B do not influence the glutathione reductase system of erythrocytes, and since endogenous erythrocyte GSH is not correlated with Cd-B, the moderate decrease in endogenous erythrocyte Gsh found in Pb-exposed workers might result from a Pb-induced impairment for the erythrocyte mechanism for glutathione synthesis.     

Comparative study of effect of inorganic lead and cadmium on blood δ-aminolevulinate dehydratase in man

Lauwerys, R. R., Buchet, J.-P., and Roels, H. A. (1973).British Journal of Industrial Medicine,30, 359-364. Comparative study of effect of inorganic lead and cadmium on blood δ-aminolevulinate dehydratase in man. δ-Aminolevulinate dehydratase (ALA¹-D) of red blood cells, lead concentration in blood (Pb-B) and in urine (Pb-U), cadmium concentration in blood (Cd-B) and in urine (Cd-U), and ALA in urine (ALA-U) were measured in 77 workers occupationally exposed to cadmium, and in 73 control workers.

An excellent negative correlation was found between log ALA-D and Pb-B (r = - 0·660) or Pb-U (r = - 0·501), but no significant correlation was found between Cd-B and log ALA-D activity.

Unlike ALA-D, ALA-U is not correlated with Pb and Pb-U in the `normal' range of Pb concentration investigated. Mean ALA-D activity in smokers is lower than in nonsmokers, and this is probably related to the fact that a higher mean Pb-B concentration is found in smokers than in nonsmokers.

It is clear from this investigation that in the general population, and even in Cd-exposed workers, Cd has no significant effect on ALA-D. Moreover, all the available evidence indicates that ALA-D activity of erythrocytes is a very sensitive and specific parameter of lead in blood.

     

Lead exposure in highway toll-booth workers

Biomarkers of lead exposure (blood lead, BPb) and effect (erythrocyte protoporhyrin, EP, and activity of delta-aminolevulinic acid dehydratase, ALAD) were measured in 68 male toll-booth operators (aged 22-60 years) on the Zagreb-Karlovac motorway. Average values (arithmetic mean +/- standard deviation) were: 61.8 +/- 29.3 micrograms/L for BPb, 0.70 +/- 0.20 mumol/L erythrocytes for EP, and 50.6 +/- 9.8 U/L erythrocytes for ALAD. All were within the normal range determined for general population (BPb < 150 micrograms/L, EP < 1.62 mumol/L erythrocytes, and ALAD > 35 U/L erythrocytes). A significant positive correlation was found between BPb and EP (r = 0.367, P < 0.01) and an inverse correlation between BPb and ALAD (r = -0.271, P < 0.05) and for EP and ALAD (r = -0.381, P < 0.01). Significant correlations were found between BPb or ALAD and smoking index (r = 0.486, P < 0.01, and r = -0.322, P < 0.01, respectively), whereas BPb also significantly correlated with blood gamma-glutamyl transferase (GGT) activity, which may indicate hepatotoxic effect of alcohol consumption (r = 0.334, P < 0.01). Among standard spirometric tests, BPb inversely correlated with FEV1 (r = -0.251, P < 0.05) and Tiffenau index (r = -0.280, P < 0.05), whereas ALAD positively correlated with FEF75-85 (r = 0.261, P < 0.05) and Tiffenau index (r = 0.314, P < 0.01). Among standard hematologic tests, BPb positively correlated with MCV (r = 0.282, P < 0.05), EP inversely correlated with erythrocyte count (r = -0.253, P < 0.05), and ALAD positively correlated with MCHC (r = 0.306, P < 0.05) and inversely with MCV (r = -0.250, P < 0.05). Although PbB values in these workers are within occupational exposure limits, they are higher than in corresponding occupations in developed countries. This may be explained by greater exposure to lead in ambient air, tobacco (through mainstream and sidestream smoking) and alcohol in this population.     

Lead and cadmium levels in daily foods,blood and urine in children and their mothers in Korea

OBJECTIVES: The present study was initiated to examine the dietary intake, blood level and urinary concentration of lead (Pb) and cadmium (Cd) among children in Korea, in comparison with the findings in their mothers. METHODS: Peripheral blood, spot urine and 24-h food duplicate samples were collected in Busan, Korea, from 38 pairs of children (4-10 years of age) and their mothers (28-46 years, non-smoking, mostly housewives), who provided informed consent. Samples were wet-ashed by being heated in the presence of mineral acids, and Pb and Cd in the wet-ashed samples were analyzed by graphite furnace atomic absorption spectrometry. Pb and Cd in food (Pb-F, Cd-F), blood (Pb-B, Cd-B) and urine [observed value (Pb-Uob, Cd-Uob), and values corrected for creatinine (Pb-Ucr, Cd-Ucr) or a specific gravity (1.016; Pb-Usg, Cd-Usg)] were presented in terms of geometric mean (GM) and geometric standard deviation (GSD). RESULTS: Pb-F and Cd-F in the children were 0.337 microg Pb and 0.457 microg Cd/kg body weight per day as GM, respectively. Pb-B and Cd-B were 38.0 microg Pb and 1.51 microg Cd/l, and Pb-U and Cd-Uob were 5.44 microg Pb/l and 1.33 microg Cd/l, respectively. Pb-F and Pb-B for children were not significantly different from the values for their mothers. In contrast, Cd-F and Cd-B were significantly different between children and their mothers. Cd-F for children correlated with Cd-F for mothers, but no significant correlation was observed in Cd-B, Cd-U, Pb-F, Pb-B or Pb-U between children and their mothers. The dietary intake of Pb in total Pb intake (i.e., respiratory and dietary intake) accounted for 51.7 and 64.8% in children and their mothers, respectively, whereas the corresponding proportions were 97.8 and 98.2%, respectively, for Cd. CONCLUSION: Cd intake was exclusively from food, both in children and mothers. Dietary Cd intake of children significantly correlated with that of their mothers. Dietary Pb intake in children, however, did not correlate with that of their mothers. Pb uptake from ambient air tended to be higher in children than in their mothers.     

Correlation between urine and blood concentrations, and dietary intake of cadmium and lead among women in the general population of Japan

Objective: To examine whether lead (Pb) in urine and cadmium (Cd) in blood, especially the former, can be used as markers of environmental exposure of general populations to these metals. Methods: Between 1991 and 1998, spot urine and peripheral blood samples, together with 24 h duplicates of food intake were collected from 607 non-smoking adult women in 30 survey sites (SS) in seven administrative regions all over Japan. Urine, blood and food duplicate samples were analyzed by inductively-coupled plasma spectrometry, for Cd and Pb in urine (Cd-U and Pb-U), in blood (Cd-B and Pb-B) and in food duplicates (Cd-F and Pb-F). Correlation between the measurements was examined by regression analysis. Results: The Cd-B correlated closely with Cd-U, and both Cd-B and Cd-U with Cd-F, on an individual basis (n = 607), on an SS basis (n = 30) and on a regional basis (n = 7). The Pb-U however did not correlate with Pb-B on a regional basis although they correlated with each other when analyzed on an individual as well as SS basis. Moreover, the correlation coefficients between Pb-U and Pb-B were much smaller than those between Cd-U and Cd-B. Neither Pb-U nor Pb-B showed significant correlation with Pb-F on any levels of statistical analysis. Conclusions: Both Cd-B and Cd-U can be employed as biomarkers of environmental Cd exposure. The reliability of Pb-U for use in place of Pb-B appeared to be small. Received: 21 January 1999 / Accepted: 2 November 1999     

Relationship between delta-aminolevulinic acid dehydratase genotypes and heme precursors in lead workers

BACKGROUND: The objective of this study was to investigate the relationships between genotypes of delta-aminolevulinic acid (ALA) dehydratase (ALAD) and disturbances in the heme biosynthetic pathway by lead exposure. METHODS: The subjects were 192 male lead workers and 125 control subjects. Blood lead concentrations (Pb-B), plasma ALA concentrations (ALA-P), and ALAD genotypes were determined for all subjects. In lead workers, ALAD activity, ALA in urine (ALA-U), and erythrocyte zinc protoporphyrin (ZP) were also determined. RESULTS: The frequency of ALAD2 (minor type of ALAD allele) was calculated to be 0.087 in all subjects. No significant relationship was found between ALAD2 frequency and Pb-B levels in lead workers. ALAD1 homozygotes showed significantly higher levels of ZP and ALA-P in comparison with those of ALAD2 carriers at Pb-B levels more than 20 microg/dL and 40 microg/dL, respectively. CONCLUSIONS: ALAD1 homozygotes might be more susceptible than ALAD2 carriers to disturbances in heme metabolism caused by lead exposure.     

Relationships between blood lead concentration and aminolevulinic acid dehydratase in alcoholics and workers industrially exposed to lead

Blood lead concentration (Pb-B), aminolevulinic acid dehydratase (ALAD), and gamma-GT were measured in 265 workers industrially exposed to lead and in 184 patients with liver disease resulting from alcohol consumption. The first group was divided according to alcohol use, i.e., nondrinkers, moderate drinkers, and heavy drinkers. The second group was divided according to the following criteria: hepatopatic without cirrhosis, hepatopatic with compensated cirrhosis, and hepatopatic with decompensated cirrhosis. Heavy drinkers who were industrially exposed had the highest Pb-B (40.4 +/- 14.6 micrograms/dl) and the lowest ALAD (22.2 +/- 9.1 U/L). The correlations between Pb-B and ALAD show no significant change with the increase of Pb-B. In the alcoholic group, 76 patients with alcoholic liver disease without cirrhosis had the highest Pb-B (40.3-9.1 micrograms/dl) and ALAD the lowest (18.6 +/- 7.7 U/L). The negative correlation between Pb-B and log ALAD disappeared completely in individuals with Pb-B that exceeded 50 micrograms/dl, independent from the seriousness of illness.     

Biological Response and Subjective Symptoms in Low Level Lead Exposure

Workers occupationally exposed to lead in the air of up to 60μg/cu m were examined for blood lead (Pb-B), urinary δ-aminolevulinic acid (ALA), erythrocyte ALA dehydrase (ALAD), hemoglobin, hematocrit, red blood cell count, and subjective symptoms.

The Pb-B and ALAD showed consistent increases and decreases, respectively, corresponding with the levels of Pb exposure, while other tests revealed no association with Pb. The range of Pb exposure as expressed by Pb-B was up to 50μg/100 gm. Subjective symptoms and urinary ALA are not likely to be increased at the Pb-B level of about 50μg/100 gm and less.     

Impact of Air Pollution by Lead on the Heme Biosynthetic Pathway in School-Age Children

Blood-lead level (Pb-B), erythrocyte δ-aminolevulinic acid dehydratase (ALAD) activity, free erythrocyte porphyrin (FEP) concentration, δ-aminolevulinie acid concentration in urine (ALAU), hematocrit value, and hemoglobin concentration were compared for groups of children 10–13 years old from areas differently polluted by lead (rural area and lead smelter area). The biological responses of the children were also compared with those observed in adults similarly exposed to lead (Pb-B: 10–40 μ/100 ml). Compared with the rural children, children living less than 1 km from the smelter exhibited a significant increase of Pb-B and FEP, a significant inhibition of ALAD, and a slight positive correlation of ALAU with Pb-B; however, they showed no biological signs of anemia. In children living approximately 1.5 km from the smelter, there was still a signfiicant increase of Pb-B and a concomitant inhibition of ALAD, but no change in FEP concentration. Comparison of the dose-response curves between Pb-B and FEP in adult males, adult females, and children indicates that the sensitivity to lead is in the order of children ≥ women > men. Based on the FEP response, it is proposed that 25 μ Pb/100 ml blood be regarded as the maximum biologically allowable concentration of lead in blood of school-age children.     

Distribution of blood lead, blood cadmium, urinary cadmium, and urinary arsenic levels in employees of a copper smelter

A cross-sectional medical examination of a copper smelter work force included determination of blood lead (Pb-B), zinc protoporphyrin (ZPP), blood cadmium (Cd-B), urinary cadmium (Cd-U), and urinary arsenic (As-U), since it was known that such metal impurities were present in the copper concentrate. A total of 776 copper smelter employees (680 active and 96 retirees and ex-employees) were examined. Another 144 men, never employed in the smelter, but who had worked in copper mines (and sometimes in gold mines) were also examined. Mean Pb-B, ZPP, Cd-B, and As-U were significantly higher in active copper smelter employees than in retirees or miners, indicating exposure and absorption in the copper smelter. Significant correlations between Pb-B and Cd-B, and Cd-U and As-U were present, confirming the common source of absorption. Although there was evidence for an increased lead absorption, this was very moderate, with practically no Pb-B levels in excess of 60 micrograms/dl. A marked effect of smoking on blood cadmium levels was present; nevertheless, for all smoking categories Cd-B levels were significantly higher in active employees, indicating the independent contribution of exposure to cadmium in the smelter. Cd-U did not exceed 10 micrograms/g creatinine, the generally accepted "critical" level for the kidney, but was higher than 2 micrograms/g creatinine, a level very rarely exceeded in the general population, in a sizable proportion of those examined. The highest Cd-U levels were found in retired copper smelter employees; age might have been a contributing factor, besides a longer duration of exposure in the smelter.     

The relationship between cadmium exposure or body burden and the concentration of cadmium in blood and urine in man

Summary Cadmium concentration in whole blood (Cd-B) and in urine (Cd-U) has been determined in more than 100 workers exposed to cadmium and in a comparable group of non-exposed workers. The relationship between both parameters and the duration of employment or the intensity of current exposure has been analyzed.In control workers slightly exposed to environmental pollution by cadmium, Cd-U but not Cd-B is significantly correlated with duration of exposure.In exposed workers both Cd-U and Cd-B are correlated with the intensity of exposure but not with the duration of exposure. It is suggested that Cd-B reflects current exposure but that Cd-U may reflect body burden of cadmium when exposure is low (environmental pollution) and current exposure when exposure is high (industrial situations).This work was supported by the Commission des Communautés Européennes and the Fonds National de la Recherche Scientifique.     

Determination of delta-aminolevulinic acid dehydratase (ALAD) by enzyme immunoassay and its application to evaluation of lead exposure

Enzyme Immunoassay (EIA) technique using a glass bead was established in order to quantify the total amount of delta-aminolevulinic acid dehydratase (ALAD, EC 4, 2, 1, 24) including an inactivated enzyme and to determine the level of ALAD in erythrocytes of workers with moderate lead exposure. EIA was carried out by competitive antibody binding method in which the antigen (ALAD) was linked to a glass bead (O.D. 7 mm). A standard curve was fitted to the function y = A X B/(x-B) + C, where y is the enzymatic reaction product, x is the concentration of ALAD, and A, B and C are parameters. The coefficients of variation in the intra- and inter-assay were 3.7% and 6.5%, respectively. EIA-based amount of ALAD was 136.7 +/- 23 mg/l erythrocyte (mean +/- S.D.) in 66 workers. This ALAD amount was not found to be correlated with the lead level in the blood but correlated with the duration of lead-exposure. An especially good correlation (r = 0.453) was obtained with the inactivated portion of ALAD (EIA-based amount minus activity-based amount). On the other hand, the ratio of restored activity following heat treatment and addition of Zn and dithiothreitol to non-restored activity was well correlated with the lead level (r = 0.874), but not correlated with the duration of lead-exposure (r = 0.218). The inactivated portion of ALAD based on EIA accordingly may be considered a good indicator of the duration of lead exposure, and the activity-based amount of ALAD may be considered a suitable indicator of the extent of the present lead exposure.     

Lead effect on blood pressure in moderately lead-exposed male workers

BACKGROUND: The effect of lead (Pb) and potential confounding variables on blood pressure was examined in healthy male industrial workers 20-43 years of age. METHODS: In 100 Pb workers and 51 reference subjects, the following variables were measured: blood Pb (BPb), activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), blood cadmium (BCd), serum zinc (SZn), serum copper (SCu), hematocrit (Hct), body mass index (BMI), and blood pressure. The inter-relationship of biomarkers of Pb (BPb, ALAD, EP) and BCd, SZn, SCu, Hct, BMI, age, smoking, and alcohol to systolic and diastolic blood pressure was calculated by forward stepwise multiple regression. RESULTS: There was no significant difference in blood pressure between the two groups, possibly because the reference subjects had relatively high BPb levels and significantly higher BMI (P < 0.05) as compared to the Pb workers. According to the multiple regression results in Pb workers, an increase in systolic blood pressure was significantly associated with increasing EP (P = 0.001) and BMI (P < 0.002), or alternatively with increasing BMI (P < 0.004) and decreasing ALAD (P < 0.04) and BCd (P < 0.05). An increase in diastolic blood pressure was significantly associated with increasing BMI (P < 0.009) and EP (P = 0.05) and decreasing BCd (P < 0.04). With respect to the EP range of 0.73-13.94 micromol/l erythrocytes in 100 Pb workers, an increase of 17 mm Hg in systolic and 6 mm Hg in diastolic blood pressure was found. CONCLUSIONS: Long-term cumulative Pb exposure, which is better reflected by EP than by ALAD or current BPb level, can significantly increase blood pressure in moderately Pb-exposed male workers (long-term average BPb <400 microg/l; exposure duration 2-21 years).     

δ-Aminolevulinic acid in plasma or whole blood as a sensitive indicator of lead effects,and its relation to the other home-related parameters

 To evaluate the subclinical effect of lead exposure, we determined δ-aminolevulinic acid (ALA) levels in plasma (ALA-P), blood (ALA-B), and urine (ALA-U) and the activity of δ-aminolevulinic acid dehydratase (ALAD) in lead workers. Almost all of the ALA molecules in blood were present in plasma and not in blood cells, irrespective of the blood lead concentration (Pb-B). ALA-P or ALA-B levels increased slowly at Pb-B levels below 40 μg/dl (slow phase) and rapidly at levels above 40 μg/dl (rapid phase). In both phases, ALA-P and ALA-B were well correlated with Pb-B and ALAD activity. The threshold value (no-effect level) of Pb-B for elevation of the ALA-P or ALA-B level was coincident with that for ALAD inhibition; the value was around 5 μg/dl. In the rapid phase, ALA-P increased continuously up to 100 μg/dl of Pb-B, while ALAD activity reached a plateau. Receiver operative characteristic (ROC) plot analyses indicated that ALA-P and ALAD activity [ALAD(u)] had a similar diagnostic value at Pb-B levels between 10 and 40 μg/dl, although ALAD(%), the remaining ALAD activity as a percentage of the whole activity restored by zinc and dithiothreitol, had the most powerful diagnostic efficiency at these Pb-B levels. By contrast, ALA-U and zinc protoporphyrin were less effective for the diagnosis of lead exposure than ALAD and ALA-P. These findings indicate that ALA-P is the best discriminators of lead exposure form baseline to high levels of exposure. Received: 18 October 1994/Accepted: 11 September 1995     

Evidence for erythrocyte lipid peroxidation in acute falciparum malaria.

To assess the extent of oxidative stress in erythrocytes of patients with acute Plasmodium falciparum malaria, erythrocyte thiobarbituric acid-reactive substance (ETBAR), and intracellular, membrane and extracellular antioxidants were estimated in 102 cases of P. falciparum malaria and 50 control subjects. The mean concentration of ETBAR was significantly higher (P < 0.001) and many of the antioxidants were significantly lower in patients than controls. Among the erythrocyte antioxidants, catalase, reduced glutathione (GSH) and tocopherol were significantly lower in the patients (P < 0.05, 0.001, 0.001, respectively). Erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were not reduced to a statistically significant level. Similarly, the plasma antioxidants ascorbate and albumin were significantly lower (P < 0.001) but not urate. ETBAR correlated inversely with erythrocyte GSH and tocopherol (P < 0.001), and plasma ascorbate and albumin (P < 0.001) but not with the erythrocyte enzymic antioxidants. However, on multiple regression analysis only tocopherol correlated strongly with ETBAR, followed by GSH and plasma ascorbate. ETBAR also correlated well with haemolytic indices such as haemoglobin, plasma unconjugated bilirubin and haptoglobin concentrations (P < 0.001, for all). On follow-up after 2 weeks, ETBAR and different antioxidants reached near control levels. These observations indicate an enhanced oxidative stress on erythrocytes in acute falciparum malaria that may contribute substantially to haemolysis and anaemia.     

Du-zhong (Eucommia ulmoides Oliv.) cortex water extract alters heme biosynthesis and erythrocyte antioxidant defense system in lead-administered rats

This study examined the ameliorative effect of a Du-zhong (Eucommia ulmoides Oliv.) cortex water extract (DzCw) on heme biosynthesis and erythrocyte antioxidant enzyme activities in lead (Pb)-administered rats. Male rats were divided into three groups: normal control group, Pb control group (Pb), and DzCw-administered Pb group (Pb + DzCw). The Pb (25 mg/kg of body weight) was administered orally once a week for 4 weeks, while the DzCw was administered orally at a dosage of 0.139 g of DzCw/kg of body weight/day. DzCw administration significantly lowered plasma Pb concentration compared with the Pb group. Furthermore, the blood hematocrit and hemoglobin levels were significantly higher in the Pb + DzCw group than in the Pb group. Although the blood and hepatic delta-aminolevulinic acid dehydratase (ALAD) activities were significantly lower in the Pb group compared with the normal control group, both ALAD activities was normalized with the administration of DzCw. The erythrocyte superoxide dismutase and catalase activities were significantly higher in the Pb group than in the normal control group, whereas the glutathione peroxidase activity and glutathione level were lowered by Pb administration compared with the normal group. However, the administration of DzCw was found to enhance the antioxidant defense system and significantly lower lipid peroxidation levels in erythrocytes compared with the Pb group. These results indicate that the DzCw administration alleviated the Pb-induced oxidative stress in the erythrocytes through elevating the blood and hepatic ALAD activity and enhancing the antioxidant enzyme activities.     

Occupational lead exposure in Finland. V. Shipyards and shipbreaking.

Three Finnish shipyards and two shipbreaking enterprises were studied for lead exposure. Blood lead (Pb-B) concentration was measured for 568 workers in the shipyards and 13 workers in the shipbreaking enterprises. Erythrocyte delta-aminolevulinic acid dehydratase (ALAD) activity was determined for 139 workers in one shipyard and 7 workers in one shipbreaking enterprise. Hemoglobin level was determined for 545 workers in the three shipyards and 7 workers in one shipbreaking enterprise. Lead exposure in the shipyards was relatively low. No Pb-B value exceeded 70mug/100 ml. The most exposed occupations were welders, plumbers, painters, repairmen, and sheet metal workers. The mean Pb-B did not exceed 40 mug/100 ml in any of these groups. In both shipbreaking enterprises one Pb-B value exceeded 70 mug/100 ml, the mean Pb-B values of all the workers in the two enterprises being 51 and 46 mug/100 ml. respectively. ALAD values corresponded well with the respective Pb-B values. All the hemoglobin mean values were normal, and there were no statistically significant differences between the hemoglobin values of different groups.     

Reduced cadmium and lead burden in Japan in the past 10 years

Objective To investigate the current levels of exposure of the Japanese population to cadmium and lead, in comparison with the levels in 1980s. · Design A nation wide survey was conducted in 1991–1994 (the 1990 study) in 19 study sites in Japan as a follow-up to a study conducted in 1979–1983 (the 1980 study). Blood samples and 24-h total food duplicates were collected from women who did not smoke or drink habitually. Methods Blood and food duplicates (after homogenization) were analysed for cadmium (Cd-B and Cd-F, respectively) and lead (Pb-B and Pb-F) by graphite furnace atomic absorption after wet-ashing. · Results Altogether, 467 women volunteered for blood sampling. Of these women, 375 also gave food duplicates. Geometric mean (GM) Cd-B levels in the 1990 study were lower than the corresponding 1980 values in most study sites so that the 1990 grand GM (1.98 ng/ml) for Cd-B was significantly lower than the 1980 GM (3.58 ng/ml). This reduction in Cd-B was related to the reduction in Cd-F (GM for Cd-F was 38.0 g/day in the 1980 study and 30.0 Etg/day in the 1990 study). Dietary intake was almost exclusively the route of Cd burden among the populations studied. Both Pb-B and Pb-F also showed a remarkable reduction, i.e. from 33.9 ng/ml (1980 GM) to 23.2 ng/ml (1990 GM) in the case of Pb-B, and from 32.2 g/day (1980 GM) to 7.1 g/day (1990 GM) in the case of Pb-F. Pb-B, however, did not correlate with Pb-F either in the 1980 or the 1990 study, because Pb intake via inhalation of air remained significant when compared with dietary intake. · Conclusion The Cd burden in Japan has decreased markedly in the past 10 years, although it is still higher than in other countries. The Pb burden has been quite low.     

Blood pressure in relation to biomarkers of lead, cadmium, copper, zinc, and selenium in men without occupational exposure to metals.

The interrelationship of blood lead (BPb), activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), blood cadmium (BCd), serum copper (SCu), serum zinc (SZn), serum selenium (SSe), hematocrit (Hct), body mass index (BMI), age, smoking habits, and alcohol consumption to blood pressure was examined in 154 Croatian male subjects 19-53 years of age. None of the subjects had been occupationally exposed to metals, or used any medication that could influence blood pressure or metal metabolism. The median and range values were: BPb, 57 (25-254) microg/L; ALAD, 51.9 (22.8-96.4) European units; EP, 0.68 (0.38-1.68) micromol/L erythrocytes; BCd, 0.83 (0.21-11.93) microg/L; SCu, 1113 (763-1662) microg/L; SZn, 961 (734-1213) microg/L; SSe, 73.6 (44.2-106.9) microg/L; systolic blood pressure, 131 (105-165) mm Hg; and diastolic blood pressure, 94 (71-112) mm Hg. Systolic and diastolic blood pressure significantly correlated with an increase in BMI (P<0.0005 and P<0.0001, respectively), EP (P<0.0002 and P<0.002, respectively), and BPb (P<0.005 and P<0.01, respectively). After adjusting for potential confounding variables by multiple regression, an increase in systolic blood pressure was significantly predictive by BMI (P<0.0005) and log BPb (P<0.02) and inversely by log BPb*SSe interaction term (P<0.007), or alternatively by EP (P<0.0001), BMI (P<0.001), alcohol (P<0.02), and Hct (P<0.05). An increase in diastolic blood pressure was significantly predictive by BMI (P<10(-5)), log BPb (P<0.04), and alcohol (P=0.05) and inversely by log BPb*SSe interaction term (P<0.0007), or alternatively by BMI (P<0.0001), EP (P<0.002), alcohol (P<0.004), and Hct (P<0.04) and inversely by smoking (P<0.04). With respect to the EP range in the study population, an increase of 27 mm Hg in systolic and 14 mm Hg in diastolic blood pressure was found. The study results indicate a significant Pb-related increase in blood pressure, particularly within the low-level Pb exposure range (BPb of 25-75 microg/L, and/or EP of 0.4-1.0 micromol/L erythrocytes).     

Subjective symptoms and exposure to lead

Summary In a group of men representing the general population and workers occupationally exposed to lead, we measured Pb-B concentrations of 1,828 men and the erythrocyte ALAD activities of 1,327 men and compared them with subjective symptoms as assessed by the Cornell Medical Index (CMI). No statistically significant association between symptoms and either Pb-B concentrations or ALAD activities was found up to levels of 70g/100 ml. At higher Pb-B levels the data were insufficient to allow for conclusions. The specificity of the CMI with regard to classical lead-related symptoms is low, and thus the results should be interpreted with caution, perhaps only as an evidence against the suitability of the CMI for this kind of study.