Method validation for (ultra)-trace element concentrations in urine for small sample volumes in large epidemiological studies: application to the population-based epidemiological multi-ethnic study of atherosclerosis (MESA).

Analysis of essential and non-essential trace elements in urine has emerged as a valuable tool for assessing occupational and environmental exposures, diagnosing nutritional status and guiding public health and health care intervention. Our study focused on the analysis of trace elements in urine samples from the Multi-Ethnic Study of Atherosclerosis (MESA), a precious resource for health research with limited sample volumes. Here we provide a comprehensive and sensitive method for the analysis of 18 elements using only 100 µL of urine. Method sensitivity, accuracy, and precision were assessed. The analysis by inductively coupled plasma mass spectrometry (ICP-MS) included the measurement of antimony (Sb), arsenic (As), barium (Ba), cadmium (Cd), cesium (Cs), cobalt (Co), copper (Cu), gadolinium (Gd), lead (Pb), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), strontium (Sr), thallium (Tl), tungsten (W), uranium (U), and zinc (Zn). Further, we reported urinary trace element concentrations by covariates including gender, ethnicity/race, smoking and location. The results showed good accuracy and sensitivity of the ICP-MS method with the limit of detections rangings between 0.001 µg L-1 for U to 6.2 µg L-1 for Zn. Intra-day precision for MESA urine analysis varied between 1.4% for Mo and 26% for Mn (average 6.4% for all elements). The average inter-day precision for most elements was <8.5% except for Gd (20%), U (16%) and Mn (19%) due to very low urinary concentrations. Urinary mean concentrations of non-essential elements followed the order of Sr > As > Cs > Ni > Ba > Pb > Cd > Gd > Tl > W > U. The order of urinary mean concentrations for essential trace elements was Zn > Se > Mo > Cu > Co > Mn. Non-adjusted mean concentration of non-essential trace elements in urine from MESA participants follow the order Sr > As > Cs > Ni > Ba > Pb > Cd > Gd > Tl > W > U. The unadjusted urinary mean concentrations of essential trace elements decrease from Zn > Se > Mo > Cu > Co > Mn.

Urine concentrations of selected trace metals in a cohort of Irish adults.

Human biomonitoring studies are of increasing importance in regulatory toxicology; however, there is a paucity of human biomonitoring data for the Irish population. In this study, we provide new data for urinary biomarker concentrations of aluminium, arsenic, cadmium, chromium, copper, mercury, manganese, lead and selenium. One hundred urine samples, collected between 2011 and 2014 from healthy participants of the EuroMOTOR project, were randomly selected. Metal concentrations were measured via ICPMS. Descriptive statistics for each of the metals stratified by gender were performed. There were 58 male and 42 female participants and metals were detectable for all samples. Geometric mean urinary concentrations for each metal in males were as follows: aluminium 8.5 µg/L, arsenic 8.1 µg/L, cadmium 0.3 µg/L, chromium 0.5 µg/L, copper 5.1 µg/L, mercury 0.4 µg/L, manganese 0.3 µg/L, lead 1.3 µg/L and selenium 10.8 µg/L; and in females: aluminium 8.5 µg/L, arsenic 10.2 µg/L, cadmium 0.4 µg/L, chromium 0.6 µg/L, copper 5.6 µg/L, mercury 0.3 µg/L, manganese 0.2 µg/L, lead 1.6 µg/L and selenium 13.7 µg/L. We observed higher geometric mean concentrations in women for arsenic, cadmium, chromium, copper, lead and selenium, with equal geometric mean concentrations for aluminium and manganese, leaving only mercury with lower geometric mean concentrations in women. Aluminium, cadmium, chromium, lead and urinary concentrations of metals were slightly elevated compared to European data, while for arsenic, copper, manganese and selenium, Irish levels were lower. Our findings highlight that there are differences in urinary metal concentrations between European populations.

Reproducibility of essential elements chromium, manganese, iron, zinc and selenium in spot samples, first-morning voids and 24-h collections from healthy adult men.

Evaluation of Cr, Mn, Fe, Zn and Se in humans is challenged by the potentially high within-individual variability of these elements in biological specimens, which are poorly characterised. This study aimed to evaluate their within-day, between-day and between-month variability in spot samples, first-morning voids and 24-h collections. A total of 529 spot urine samples (including eighty-eight first-morning voids and 24-h collections) were collected from eleven Chinese adult men on days 0, 1, 2, 3, 4, 30, 60 and 90 and analysed for these five elements using inductively coupled plasma-MS. Intraclass correlation coefficients (ICC) were utilised to characterise the reproducibility, and their sensitivity and specificity were analysed to assess how well a single measurement classified individuals' 3-month average exposures. Serial measurements of Zn in spot samples exhibited fair to good reproducibility (creatinine-adjusted ICC = 0·47) over five consecutive days, which became poor when the samples were gathered months apart (creatinine-adjusted ICC = 0·33). The reproducibility of Cr, Mn, Fe and Se in spot samples was poor over periods ranging from days to months (creatinine-adjusted ICC = 0·01-0·12). Two spot samples were sufficient for classifying 60 % of the men who truly had the highest (top 33 %) 3-month average Zn concentrations; for Cr, Mn, Fe and Se, however, at least three specimens were required to achieve similar sensitivities. In conclusion, urinary Cr, Mn, Fe, Zn and Se concentrations showed a strong within-individual variability, and a single measurement is not enough to efficiently characterise individuals' long-term exposures.

Urinary concentrations of environmental metals and associating factors in pregnant women.

Pregnant women, a vulnerable population, can be exposed to a variety of environmental metals that may adversely affect their health at elevated concentrations. Moreover, environmental exposure and risk disparities are associated with several factors such as sociodemographic characteristics, pregnancy complications, and nutritional supplementation indicators. Our aim was to investigate whether and how the urinary metal concentrations vary according to these factors in a large pregnancy and birth cohort. Urinary levels of seven metals including manganese, zinc, selenium, arsenic, cadmium, thallium, and lead were assessed in 7359 participants across Wuhan City in China. In all, 7359 urine samples from the third trimester were analyzed and 15 sociodemographic characteristics, pregnancy complications, and nutritional supplementation indicators were assessed: maternal age, household income, multivitamin supplements during pregnancy, etc. Concentrations of Zn, As, and Cd were detected in all urine samples; Mn, Se, Tl, and Pb were detected in 95.3%, 99.8%, 99.8%, and 99.9% urine samples, respectively. The geometric mean (GM) of creatinine-adjusted urinary Mn, Zn, Se, As, Cd, Tl, and Pb concentrations were 1.42, 505.44, 18.24, 30.49, 0.64, 0.55, and 3.69 µg/g. Factors that associated with environmental metals concentration were as follows: (1) Urinary Zn and Cd concentrations increased with maternal age. (2) Pregnant women with higher education had lower Cd concentrations. (3) Pregnant women with folic acid supplementation had lower Mn and with multivitamin supplementation had higher Se and lower Tl. Our results demonstrated that the maternal age, education level, folic acid supplementation, and multivitamin supplementation were significantly associated with environmental metal concentrations. Furthermore, studies are recommended to explore the influence of diet on biological metals concentrations in more detail.

Trace elements are associated with urinary 8-hydroxy-2'-deoxyguanosine level: a case study of college students in Guangzhou, China.

Many trace heavy elements are carcinogenic and increase the incidence of cancer. However, a comprehensive study of the correlation between multiple trace elements and DNA oxidative damage is still lacking. The aim of this study is to investigate the relationships between the body burden of multiple trace elements and DNA oxidative stress in college students in Guangzhou, China. Seventeen trace elements in urine samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of DNA oxidative stress, was also measured using liquid chromatography tandem mass spectrometer (LC-MS/MS). The concentrations of six essential elements including manganese (Mn), copper (Cu), nickel (Ni), selenium (Se), strontium (Sr), and molybdenum (Mo), and five non-essential elements including arsenic (As), cadmium (Cd), aluminum (Al), stibium (Sb), and thallium (Tl), were found to be significantly correlated with urinary 8-OHdG levels. Moreover, urinary levels of Ni, Se, Mo, As, Sr, and Tl were strongly significantly correlated with 8-OHdG (P < 0.01) concentration. Environmental exposure and dietary intake of these trace elements may play important roles in DNA oxidative damage in the population of Guangzhou, China.

Effects of selenium on liver and muscle contents and urinary excretion of zinc, copper, iron and manganese.

Selenium is a main component of glutathione peroxidase (GPX), a key antioxidant enzyme. Other elements, such as zinc, copper, manganese and iron, are also involved in the pathogenesis of oxidative damage as well as in other important metabolic pathways. The effects of selenium supplementation on the metabolism of these elements have yield controversial results .The aim of this study is to analyse the effects of selenium supplementation on liver, muscle and urinary excretion of zinc, copper, iron and manganese in a situation of oxidative stress, such as protein deficiency. The experimental design included four groups of adult male Sprague-Dawley rats, which received the Lieber-DeCarli control diet, an isocaloric 2 % protein-containing diet and another similar two groups to which selenomethionine (6 mg/l liquid diet) was added. After sacrifice (5 weeks later), muscle, liver and serum selenium were determined, as well as muscle, liver and urinary zinc, copper, manganese and iron and liver GPX activity and liver malondialdehyde. Selenium addition led to decreased liver copper, increased muscle copper, increased copper excretion and increased liver iron, whereas zinc and manganese parameters were essentially unaltered. Muscle, liver and serum selenium were all significantly correlated with liver GPX activity.

Arsenic exposure and motor function among children in Bangladesh.

BACKGROUND: Several reports indicate that drinking water arsenic (WAs) and manganese (WMn) are associated with children's intellectual function. Very little is known, however, about possible associations with other neurologic outcomes such as motor function. METHODS: We investigated the associations of WAs and WMn with motor function in 304 children in Bangladesh, 8-11 years of age. We measured As and Mn concentrations in drinking water, blood, urine, and toenails. We assessed motor function with the Bruininks-Oseretsky test, version 2, in four subscales-fine manual control (FMC), manual coordination (MC), body coordination (BC), and strength and agility-which can be summarized with a total motor composite score (TMC). RESULTS: Log-transformed blood As was associated with decreases in TMC [ß = -3.63; 95% confidence interval (CI): -6.72, -0.54; p < 0.01], FMC (ß = -1.68; 95% CI: -3.19, -0.18; p < 0.05), and BC (ß = -1.61; 95% CI: -2.72, -0.51; p < 0.01), with adjustment for sex, school attendance, head circumference, mother's intelligence, plasma ferritin, and blood Mn, lead, and selenium. Other measures of As exposure (WAs, urinary As, and toenail As) also were inversely associated with motor function scores, particularly TMC and BC. Square-transformed blood selenium was positively associated with TMC (ß = 3.54; 95% CI: 1.10, 6.0; p < 0.01), FMC (ß = 1.55; 95% CI: 0.40, 2.70; p < 0.005), and MC (ß = 1.57; 95% CI: 0.60, 2.75; p < 0.005) in the unadjusted models. Mn exposure was not significantly associated with motor function. CONCLUSION: Our research demonstrates an adverse association of As exposure and a protective association of Se on motor function in children.

Taurine normalizes blood levels and urinary loss of selenium, chromium, and manganese in rats chronically consuming alcohol.

The present study was undertaken to evaluate effects of dietary taurine supplementation on the homeostasis of trace elements, including Se, Cu, Mn and Cr, in rats chronically consuming alcohol. Male SD rats were fed for 8 wk a liquid form of a control diet (CD), an ethanol diet (ED), or a taurine-supplemented ethanol diet (TED). Plasma Se and Mn concentrations were significantly lower in the ED rats than in the CD rats; dietary taurine supplementation corrected alcohol-induced decreases in plasma Se and Mn levels. Chronic alcohol consumption significantly increased urinary excretion of Se (a 53% increase, p < 0.05), Cr (a 62% increase, p < 0.05), Mn (a 45% increase, p < 0.05) and Cu (a 30% increase, p < 0.05) in rats. Urinary losses of these trace elements induced by chronic alcohol consumption in rats were abolished by taurine supplementation. These results suggest that taurine supplementation in rats may protect against Se, Cr and Mn insufficiency caused by chronic alcohol-mediated loss of the trace elements in the urine.

Trace element loss in urine and effluent following traumatic injury.

BACKGROUND: Few data are available to establish recommendations for trace element supplementation during critical illness. This study quantified the loss of several elements and assessed the adequacy of manganese and selenium in parenteral nutrition (PN). METHODS: Men with traumatic injuries were grouped by renal status: adequate (POLY; n = 6), acute failure with continuous venovenous hemofiltration (CVVH; n = 2), or continuous venovenous hemodiafiltration (CVVHD; n = 4). PN supplied 300 microg/d manganese and 60 microg/d selenium. Urine and effluent (from artificial kidneys) were collected for 3 days and analyzed for boron, manganese, nickel, and silicon using inductively coupled plasma atomic emission spectrometry, and for selenium using atomic absorption spectrometry. RESULTS: POLY manganese and selenium excretion averaged (standard deviation [SD]) 7.9 (3.3) microg/d and 103.5 (22.4) microg/d, respectively. All elements except selenium were detected in dialysate (prior to use). CVVHD effluent contained 3.5 and 7.3 times more manganese and nickel than CVVH ultrafiltrate, respectively. Loss of manganese averaged 2.6%, 21%, and 73% of PN amounts for POLY, CVVH, and CVVHD groups, respectively. DISCUSSION: Minimal loss of manganese compared with the amount in PN suggests that excessive amounts are retained. POLY patients excreted more selenium than was in PN, indicating negative balance. POLY losses of boron and silicon were less than that published for healthy adults, reflecting less than typical intake, whereas loss during CVVH was in the normal reference range, possibly because of added intake from boron contamination of replacement fluids. All patients lost more nickel than amounts published for healthy adults. CONCLUSIONS: Current guidelines of 60-100 microg/d of parenteral manganese may be excessive for trauma patients. The uptake of manganese and nickel from contaminants in CVVHD dialysate should be investigated.

[The influence of occupational exposure to arsenic and heavy metals on the activity of catepsins and their inhibitors in blood serum of copper smelters]. / Wplyw zawodowego narazenia na arsen i metale ciezkie na aktywnosc katepsyn i ich inhibitorów w surowicy krwi pracowników huty miedzi.

BACKGROUND: Exposure to arsenic, lead, and cadmium poses the risk of cancer. Cathepsins (CP) and their natural inhibitors (CPI) in blood serum are markers of carcinogensis. The aim of this work was to verify the existence of relationships between the exposure to the airesaid elements and the activity of CP and CPL. MATERIALS AND METHODS: The levels of Pb and Cd in blood, Mn, Cu, Zn, Ca, Mg, Fe, Se CP as well as free and bound CPI in serum, FEP in erythrocytes, and As in urine were measured in 186 production workers of Legnica Copper Smelter (study group) and 56 administrative employees (control group) and then analyzed. RESULTS: CF levels were significantly elevated in both groups and CPI levels were elevated in the study group vs. the control group. There were no statistically significant relationships between CF and CPI levels and the remaining parameters in the study group. whereas they were found for CPI in the control group. The results indicate that occupational and environmental exposures to toxic metals (arsenic, lead, cadmium) may lead to the elevated levels of CF and CPI. CONCLUSIONS: The obtained results support the assumptions of the study.

Determination of urinary trace elements (arsenic, copper, cadmium, manganese, lead, zinc, selenium) in patients with Blackfoot disease.

To determine the relationship of arsenic, copper, cadmium, manganese, lead, zinc and selenium to Blackfoot disease (BFD, a peripheral vascular disorder endemic to areas of Taiwan, which has been linked to arsenic in drinking water) the authors measured the amount of these substances in urine from BFD patients, using atomic absorption spectrometry. Results indicate significantly higher amounts of urinary arsenic, copper, cadmium, manganese, and lead for BFD patients than for normal controls, also significantly lower urinary zinc and selenium.

Sodium iron EDTA [NaFe(III)EDTA] as a food fortificant does not influence absorption and urinary excretion of manganese in healthy adults.

NaFe(III)EDTA is a promising iron (Fe) compound for food fortification programs because of its high Fe bioavailability from meals containing dietary inhibitors of Fe absorption such as phytic acid. However, this Fe compound is not currently used in any large-scale fortification program because of concern over its possible negative influence on the metabolism of other essential minerals or its possible influence on the absorption of potentially toxic elements, such as manganese (Mn). In this study, Mn absorption and urinary excretion were studied in adults after intake of an Fe-fortified weaning cereal labeled with 54Mn. In a crossover design, the fortification of the weaning cereal with Fe as NaFeEDTA was compared with ferrous sulfate. Manganese absorption was measured by extrapolation from whole-body retention data 10-30 d after intake, and urinary excretion of 54Mn was measured over 7 d. No significant differences in 54Mn absorption or urinary excretion were found; 1.1 +/- 0.15 and 0.91 +/- 0.35% of the ingested dose was absorbed from the cereal fortified with NaFe(III)EDTA and FeSO4, respectively. Urinary excretion of 54Mn was very low; the total radioactivity in urine represented 1.1 +/- 0.55% of the absorbed dose with NaFe(III)EDTA and 0.72 +/- 0.53% of the absorbed dose with FeSO4. Until now, Fe-fortification programs have met with only limited success. The introduction of NaFeEDTA as a food fortificant could be a useful tool to provide bioavailable Fe to vulnerable groups in the population and thus aid in combating Fe deficiency.

[Microelements balance and correction in athletes++ under high muscular load]. / Balans mikro'elementov i ego korrektsiya u sportsmenov pod vozdelstvieem bol'shol myshechnol nagruzki.

The balance studies among the high-qualified adult sportsmen during the winter period of practices had shown that of the day of a 30-km cross the contents of iron, copper and manganese in the food ration fell to the lowest level of the physiological standard of people not going into sports due to sufficient physical load the process of microcomponents' secretion through bowels and kidneys was outstripping their replenishment from food. The balance of all three microcomponents was negative. During the following three days after the cross due to disbalanced food ration caused by the content of microcomponents the losses of iron and copper were not compensated. The enrichment of the food rations by the set of components caused the hold-up of iron, copper and manganese in sportsmen bodies. The increased usage of the medical iron resulted in sufficient growth of copper and manganese excretion through alimentary canal.

Mineral and nitrogen balance in lambs implanted with zeranol.

Fourteen crossbred wether lambs (average BW, 28 kg +/- 2.3) were either implanted (12 mg of zeranol) or not implanted and group-fed an 86% concentrate diet for 21 d. Lambs were then moved to metabolism stalls and fed .8 kg/d for a 10-d stall adjustment followed by a 7-d total collection of feces and urine. Feed, feces and urine were analyzed for Ca, P, Mg, Zn, Mn, Cu, and N. Apparent absorption of Mn, Cu, and N, were similar for implanted and nonimplanted lambs. Zeranol did not affect (P > .10) the retention of Mn or Cu. Zeranol decreased fecal excretion of CA 22% (P < .01), P 27% (P < .05), Mg 11% (P < .03) and Zn 9% (P < .10). This increased apparent absorption of CA 88% (P < .01), P 193% ( P < .05), Mg 9% (P < .05) and Zn 45% (P < .10) in zeranol-treated lambs. Urinary excretion of all nutrients analyzed was similar for implanted and control lambs with the exception of N, which was reduced by 24% (P < .06) in implanted lambs. The amount of Ca, Mg, and Zn retained increased 98% (P < .01), 138% (P < .03), and 60% (P < .10), respectively, in implanted lambs compared with controls. These results indicate that zeranol improved N balance and enhanced the absorption and retention of Ca, P, Mg, and Zn in lambs.

Comparative trace mineral nutritional balance of first-litter gilts under two dietary levels of copper intake.

Seven pairs of purebred Landrace first-litter gilts, housed in individual stainless-steel metabolic cages were used in this study. A low-Cu (LCu) basal diet containing only 2 mg/kg of Cu was compared to the control (CCu) diet, which was supplemented with cupric carbonate to provide 10 mg/kg of Cu. Both diets were fed at the rate of 2 kg per day to first-litter gilts during the entire pregnancy. The metabolic response under these two levels of dietary Cu intake was evaluated through nutritional balances conducted for 5 days starting at 30, 60 and 100 days of pregnancy. Total urine collection was done through teflon-coated catheters to the bladder while daily fecal collection was carried out continuously. Water consumption was measured and periodic samples were collected for analysis. Nutritional balances included DM digestibility, Cu, Zn, Fe and Mn. The LCh group consumed 4.26 mg of Cu per day while the CCu received 25 mg of Cu per day. This includes 1 mg per day in the drinking water in both groups. DM digestibility was significantly (P < 0.05) higher during early pregnancy in the LCu group compared to the CCu group, which showed a significant (P < 0.05) increase in DM digestibility from early to late pregnancy period. Dietary Cu intake had a direct effect (p < 0.05) on Cu balance but also altered the Zn and Fe nutritional balance, leaving Mn balance almost unchanged. Feces represented the almost exclusive route of excretion of trace minerals. Regardless of the dietary Cu intake, it represents more than 99.9% of the Fe and Mn, 98% of the Zn and 97% of the Cu was excreted daily through feces plus urine. The nutritional balance of Cu, Zn and Fe, in absolute amounts as well as relative to the level of intake, improved significantly as pregnancy progressed. Although relative retention of the low-Cu group was significantly improved compared to the control group, the absolute amount was still much lower. The well recognized dietary and metabolic interactions of Cu with Zn and Fe were evident in the first-litter gilts receiving the low-Cu diet during pregnancy. The absolute amount, as well as the relative retention as a % of the intake, was increased on average during the entire pregnancy for Zn by more than 70% and for Fe by more than 80% during the last third of pregnancy. In contrast Mn balance was almost unchanged. The major response to low-Cu intake was directed toward greater apparent absorption of the trace minerals which was reflected in a reduced fecal excretion.

Mineral balances in humans as affected by fructose, high fructose corn syrup and sucrose.

The utilization of selected minerals when sugars were supplemented to basal diets was investigated in two separate, laboratory-controlled human feeding studies. Fructose-fed subjects had higher fecal excretions of iron and magnesium than did subjects fed sucrose. Apparent iron, magnesium, calcium, and zinc balances tended to be less positive during the fructose feeding period as compared to balances during the sucrose feeding period. Conversely, high fructose corn syrup (HFCS) did not affect the mineral balances when compared to sucrose feeding. Subjects fed fructose experienced diarrhea which possibly decreased absorption of minerals and thus increased fecal mineral losses. No such adverse effects were noticed when HFCS was fed.

Depletion of essential elements by calcium disodium EDTA treatment in the dog.

The effect(s) of calcium disodium ethylenediaminetetraacetate (CaNa2EDTA) on the metabolism of Zn, Cu and Mn was investigated in mongrel female dogs. Dogs received either CaNa2EDTA (0.75 mmol/kg subcutaneously) or 0.9% NaCl (controls). Urine was collected every 6 h. Tissue samples were obtained from liver, kidney, duodenum, muscle, hair, skin and bone post exsanguination. CaNa2EDTA treatment increased urinary excretion of Zn, Cu and Mn, significantly when compared to controls (P less than 0.05, n = 5). Furthermore, CaNa2EDTA either decreased Zn levels (hair, duodenum, skin) and Mn levels (hair) or increased Cu levels in kidneys (P less than 0.05). These data suggest that the sustained urinary loss of Zn, Cu and Mn was probably associated, in part, with mobilization and redistribution of these essential elements from storage tissues as well as soft tissues. It was concluded that the use of calcium disodium EDTA for the management of heavy metal poisoning in dogs could adversely affect the metabolism of essential elements, particularly Zn, Cu and Mn.

Metabolic activity of manganese during late gestation of first-litter gilts.

Four pairs of littermate Landrace gilts consuming either a low manganese (LMn) basal corn-soya diet (10 mg/kg) or a high Mn (HMn) supplement diet (84 mg/kg) were maintained in individual stainless steel metabolic cages throughout gestation. On the 100th day of gestation 200 microCi of 54Mn was administered intravenously. Total collection of feces and urine was conducted for a seven-day period. The sows were sacrificed after a three-week lactation period and several tissues excised. All samples were assayed for stable Mn content and 54Mn activity. Urinary excretion of 54Mn was negligible and not dependent on dietary Mn intake. Dietary Mn intake did not influence the rate of 54Mn elimination via the feces. The biological half-life (BHL) of the body Mn pool in late gestation averaged 54 days and was not influenced by treatment. The fecal Mn of endogenous origin was similar between treatments averaging 0.24 mg/d and yielded true absorption estimates of 1.31 and 1.61 mg/d for the LMn and HMn diets or 4.41% and 0.77% of dietary intake.

Comparative effects of Ca-ethylenediaminetetraacetic acid (EDTA), ZnEDTA, and ZnCaEDTA in mobilizing lead.

Male Long-Evans rats weighing approximately 240 g were given (Pb) at 14 mg/kg as the acetate by slow iv infusion 17 days prior to chelate treatment. The chelating agents were administered by continuous iv infusion at either 1 mmol/kg over 6 hr or 6 mmol/kg over 24 hr or at 0.16 mmol/kg/day by sc injections. ZnEDTA was 60% and ZnCaEDTA 76% as effective as CaEDTA in promoting urinary Pb excretion at 1 mmol/kg over 6 hr, iv. At 6 mmol/kg/24 hr, iv, ZnEDTA was 76% and ZnCaEDTA 98% as effective as CaEDTA. Mean urinary Pb excretion for each chelate via the sc route and the lowest iv route of administration was the same. Blood delta-aminolaevulinic acid dehydratase (ALAD) activity (an indicator of Pb toxicity) was enhanced approximately twofold by CaEDTA, two and one-half-fold by ZnCaEDTA, and fivefold by ZnEDTA treatment. It is suggested that the safety of EDTA can be markedly enhanced if administered as a ZnCaEDTA chelate without appreciably diminishing its efficacy in promoting urinary Pb excretion.

An automated system for the determination of lead in blood, manganese in urine and nickel in waste water.

An automated system has been developed to analyze lead in blood, manganese in urine and nickel in waste water at a rate of 20 to 30 samples per hour. The analysis is based on direct chelation without digestion, extraction into methyl isobutyl ketone and flame atomic absorption spectrophotometry. The applicability of the system in the field of occupational and environmental medicine is discussed.