Brief communication: Choice of washing method of hair samples for trace element analysis in environmental studies.

Determination of inseparable exogenous and endogenous levels of toxic trace elements such as lead in human scalp hair has been used to understand and assess population exposure to such elements. For any such analysis, washing of the hair samples to remove superficial contamination is the foremost requirement. However, the use of such washing methods prior to elemental analysis removes minute quantities of trace elements from the hair strands. This degree of loss is dependent on the washing method employed. In the present study, the element lead has been determined in human scalp hair after three methods of hair washing. It is apparent that the nonionic detergent-acetone method is best suited for securing valid lead analysis results in human scalp hair.     

Trace Elements in the Hair of Hemodialysis Patients

Trace element disturbance is often observed in hemodialysis patients. While trace element concentrations have been reported in blood samples from hemodialysis patients, they have not been well investigated in scalp hair. In the present study, 22 trace elemental concentrations were measured by inductively coupled plasma-atomic emission spectrometry in the scalp hair of 80 male hemodialysis patients and compared with those of 100 healthy male subjects. In hemodialysis patients, the concentrations of beryllium, arsenic, magnesium, chromium, manganese, iron, selenium, molybdenum, iodine, vanadium, and cobalt were significantly higher than those in healthy subjects, while lead, mercury, copper, germanium, and bromine were significantly lower than those in the former group. No significant differences were observed for lithium, aluminum, cadmium, zinc, boron, or nickel. There were significant positive correlations between the duration of hemodialysis and the magnesium and manganese concentrations. There was a significant negative correlation between cadmium concentration and the duration of hemodialysis. There were significant positive correlations between dialysis efficacy (Kt/V) and magnesium, manganese, zinc, and selenium concentrations. In conclusion, trace element concentrations of the scalp hair are different between hemodialysis patients and healthy subjects. Essential trace elements, such as magnesium, manganese, zinc, and selenium, may be affected by the duration of hemodialysis and Kt/V.     

Effects of zinc, copper, and selenium on placental cadmium transport

The objective of the present study was to evaluate the potential effects of zinc, copper, and selenium on placental cadmium transport. From November 2002 through January 2003, a total of 47 healthy pregnant women from Da-Ye City, Hubei Province in Central China participated in the study. Their age, parity, gestational age, pregnancy history, and lifestyle data were obtained by questionnaire interview. The placental, whole-blood, and cord blood levels of cadmium were determined by inductively coupled plasma mass spectrometer (ICP-MS), whole-blood zinc was measured by flame atomic absorption spectrometry (F-AAS), whole-blood copper by ICP-MS, and selenium was by atomic fluorescence spectrophotometry (AFS). The cord blood cadmium concentration (0.020-1.48 microg/L) was significantly lower than in maternal blood (0.80-25.20 microg/L, p<0.01). The placental cadmium concentration was from 0.082 to 3.97 microg/g dry weight. Multiple linear regression analysis indicated that lower levels of maternal blood copper were significantly associated with higher cadmium concentrations in cord blood. Placental cadmium in women with lower levels of maternal blood zinc was significantly higher than in those with normal zinc levels. The placental cadmium level in women with lower whole-blood selenium was significantly lower than in subjects with normal selenium levels. It was concluded that the essential elements copper, selenium, and zinc might significantly affect placental cadmium transport.     

Serum and hair levels of zinc, selenium, iron, and copper in children with iron-deficiency anemia

In the present study, the serum and hair levels of zinc, selenium, and copper were determined in children with iron-deficiency anemia (IDA). A total of 52 anemic children aged 1–4 yr constituted the study group. Fortysix healthy children acted as controls. The copper and zinc levels were measured with an atomic absorption spectrophometer. Serum and hair selenium was determined by a spectroflourometric method. The serum zinc and selenium concentrations in the IDA group were found to be significantly lower and serum copper significantly higher than those in the controls (p<0.05). Lower iron, zinc, and selenium concentrations (p<0.001) but not copper were found in hair (p>0.05).     

Rapid and direct determination of selenium, copper, and zinc in blood plasma by flow injection-inductively coupled plasma-mass spectrometry

A flow injection-inductively coupled plasma-mass spectrometry (FI-ICP-MS) with a simple sample preparation procedure was developed for the determination of selenium, copper, and zinc in blood serum/plasma. A serum/plasma sample was filtered through a 0.45-μm membrane filter and diluted with a mixture of trace elements in a standard solution (9∶1, v/v). Measurement of the reference serum sample confirmed the accuracy of our method for selenium, copper, and zinc concentration. In the case of blood plasma samples obtained from six healthy adult males, the selenium, copper, and zinc concentrations were similar to those of a typical healthy male in Japan. These results suggest that the sample prepartive procedure coupled with FI-ICP-MS can be used for the routine determination of selenium, copper, and zinc in human blood serum/plasma.     

Metallic Elements in Hair as a Biomarker of Human Exposure to Environmental Pollution: A Preliminary Investigation in Hubei Province

Metallic elements in hair were assessed in human subjects randomly sampled from six villages in Hubei province, PR China, known to differ in industrial pollution. Metallic elements assessed included copper, zinc, lead, and cadmium. Subjects sampled included adults and children of both sexes. Soil and rice samples from the villages were also examined for contents of metallic elements. Soil and rice contents of copper, lead, and cadmium were higher in the villages closer to the pollution source (copper smeltery). Hair contents of copper, lead, and cadmium were higher in subjects from the polluted villages compared with subjects from the nonpolluted areas. No differences were found in hair zinc content among the villagers. Cadmium contents in rice and human hair were linearly correlated. For lead and copper a logarithmic relation was found. No difference was found between the two genders with respect to hair metallic contents. With regard to age, hair cadmium content was highest in the older age groups in the polluted villages and may reflect chronic exposure. No other systematic age effects were observed. It was concluded that contents of cadmium, lead, and copper in human hair do reflect the degree of environmental pollution.     

Determination of metal concentrations in animal hair by the ICP method

Concentrations of minor and trace elements (Mg, Ca, Fe, Ba, Cu, Zn, Cd, Ni, Al, Mn, Cr, Ti, and V) in the hair of three races of dogs (fox terrier, schnauzer, and mini schnauzer) were analyzed by the inductively coupled plasma-atomic emission spectrometry method. The influence of five washing solutions, deionized water, acetone, methanol, EDTA, and Triton X-100, on the concentrations measured in hair was investigated. Triton X-100 was found to be suitable to use for the removal of exogenous elements in multielemental hair analysis. Additionally, the results indicated that the concentration of the elements measured in the dogs' hair were similar to those reported for human hair. The relation between the element content in the dog hair and its color were similar to those found for human hair.     

Cadmium induced lipid peroxidation in rat testes and protection by selenium

The main goal of this study was to investigate the role of cadmium in the promotion of lipid peroxidation in the homogenates of rat testes and the effect of selenium on lipid peroxidation in testes of rats after cadmium injection. Treatment of rats with cadmium resulted in a time- and dose-related accumulation of the metal ions in testes. The concentrations of cadmium, copper, zinc, selenium and iron in the tissues were determined by an atomic absorption spectrophotometer and lipid peroxidation in testes was measured by a spectrophotometer. Cadmium produced enhanced lipid peroxidation in testes. These cadmium-induced changes were accompanied by a significant increase of iron and copper, and a decrease of zinc in testes. Concurrent treatment with selenium and cadmium reduced the cadmium-induced alterations in lipid peroxidation and essential metal levels. Data suggest that lipid peroxidation was associated with cadmium toxicity in testes and that the addition of selenium was found to be effective in attenuation of this effect.     

Mercury concentrations in hair exposed in vitro to mercury vapor

Hair is often used as an index of environmental and industrial exposure to different metals. The interpretation of metal levels in hair is difficult because of the risk of external contamination. The aim of this study was to define the degree of external contamination of hair exposed in vitro to mercury vapor. Specimens of hair were exposed to concentration: 0.026, 0.21, and 2.7 mg Hg/m³ for 2–28 d. Mercury levels in hair increased during 28 d of exposure 2, 3 and 13, times, respectively, when compared to initial values. Mercury levels in hair exposed to the first and second (but not third) concentration of mercury vapor attained a steady state on the 21st d of exposure. The contamination of hair with mercury could not be removed by washing with water, solvent, and detergent. Hair may be used as an index of internal uptake of mercury provided that it was not externally exposed to mercury vapor. In cases of occupational exposure to mercury vapor, hair could become a useful tool for monitoring exposures.     

A Comparison of Washing Methods for Hair Mineral Analysis: Internal Versus External Effects

A major difficulty in hair elemental (mineral) analysis for biomonitoring is adequate understanding of the effectiveness of washing procedures. A review of washing protocols used in hair analysis publications showed little consensus with regard to solvents and surfactants used, washing times, and number of washing stages. Two washing approaches were subsequently used to compare their influence on internal and external surface elemental signals determined with time-of-flight secondary ion mass spectrometry. Na, K, Ca, Mg, and Fe were assessed with regard to their relative signal compared to carbon. Both washing methods had similar effect. All elements except for Fe appear to be removed from the surface of the hair as well as from inside the hair. Only the internal Fe content changed with washing and could indicate that external surface bound Fe may not be removed with most washing procedures. It is shown that washing procedures can have a significant effect on reducing the internal elemental signal levels in hair.     

Cadmium, copper and zinc in tissues of deceased copper smelter workers

Workers at a copper and lead smelter in northern Sweden have a multifactorial exposure to a number of heavy metals. The concentrations of cadmium, copper and zinc in liver, lung, kidney and brain tissues have been determined by atomic absorption spectrometry in 32 deceased long-term exposed male lead smelter workers, and compared with those of 10 male controls. Furthermore, copper and zinc levels in hair and nails were determined by energy-dispersive X-ray fluorescence.

The highest cadmium concentrations among both workers and controls were observed in kidney, followed in order by liver, lung and brain. The levels in kidney, liver and lung were all significantly higher in the workers than in the controls (p < 0.03). Among the workers relatively strong positive correlations (p < 0.03) were observed between cadmium concentrations in liver and lung, liver and kidney, liver and brain, and lung and brain. In the exposed workers a positive correlation was observed between cadmium and zinc concentrations in the kidney (r_s = 0.38; p = 0.034). This is probably mainly due to the protein metallothionein, which is stored in the kidney, binding equimolar amounts of these two metals.

The highest concentrations of copper were found in hair and nails among both workers and controls, followed in order by liver, brain, kidney and lung. The tissue concentrations of copper in brain, lung and kidney were all significantly higher among the smelter workers than in the controls (p ≤ 0.036). Copper levels in lung and age at time of death were positively correlated among the exposed workers (r_s = 0.39; p = 0.029). In the same group, positive correlations between copper and zinc concentrations in kidney (r_s = 0.45; p = 0.009) and nails (r_s = 0.68; p < 0.001) were also observed, reflecting possible biological interactions between these two metals.

Among both workers and controls, the highest zinc concentrations were found in hair, followed in order by nails, liver, kidney, brain and lung. Significantly higher tissue concentrations among the workers as compared with the reference group were noted in kidney, liver and brain (p ≤ 0.033).

Neither copper nor zinc concentrations in hair and nails seemed to provide a useful measure of the trace element status of the smelter workers.     

Long-term zinc and iron supplementation in children of short stature: effect of growth and on trace element content in tissues.

We evaluated the effect of one year of supplementation with iron plus zinc (12 mg/day of Fe+++ and 12.5 mg/day of Zn++), zinc alone (12.5 mg/day of Zn++) and placebo on growth and on the iron, zinc, copper and selenium tissue contents in 30 well-selected children of short stature (16 M and 14 F; 4-11 years old). Before and after supplementation, we measured the concentrations of iron, transferrin, ferritin, zinc and copper in serum, of zinc in erythrocytes and leukocytes, and of zinc, copper and selenium in hair, as well as glutathione peroxidase activity in erythrocytes. Before supplementation, ferritin and serum, erythrocyte and hair zinc contents were significantly lower than in age-matched controls, while the other measured indices were in the normal range. Iron plus zinc supplementation caused an improvement in growth rate in all subjects, i.e., the median Z-score increased from -2.22 +/- 0.45 to -0.64 +/- 0.55; (p < 0.01). In the zinc-supplemented group, only the subjects whose ferritin levels were higher than 20 ng/L before supplementation showed a similar improvement of growth rate. Iron plus zinc supplementation could be a reasonable treatment in short, prepubertal children affected by marginal zinc and iron deficiency.     

Validity of hair mineral testing

The variance of testing was compared between the College of American Pathologists clinical survey and that of a recent review about hair mineral testing. The review suggested that the accuracy of hair mineral testing was unreliable. In general, there was a greater range of variance in the College of American Pathologists testing results. These latter results are based on laboratory testing and are used as a “yardstick” to determine if a laboratory passes or fails that analyte and are considered a “gold standard.” An extract, which resulted from a method that avoided the washing step, was compared among five laboratories. Very good precision resulted, indicating that the varied washing steps used by the laboratories in a recent review were probably the source of much variance. Analysis of hair analysis seemed to yield important information in several historical or forensic cases involving Ludwig von Beethoven, Napoleon Bonaparte, ex-US-presidents Zachary Taylor and Andrew Jackson, and Charles Hall, an Arctic explorer. Several elements that were reviewed, including arsenic, cadmium, cobalt, germanium, lead, lithium, manganese, mercury, nickel, and thallium, showed relationships between body burden, dosage, and exposure or toxicity. Evidence of toxicity could not be found by measuring hair aluminum or vanadium. Chromium, selenium, and zinc seemed to have nutritional value. Ratios of hair elements with clinical importance could not be found.     

Effects of Different Medical Treatments on Serum Copper,Selenium and Zinc Levels in Patients with Rheumatoid Arthritis

The aim of the present study was to measure the changes in serum selenium, zinc, and copper in patients being treated for rheumatoid arthritis. Thirty-two patients and 52 healthy controls were included in the study. The copper level was higher and those of selenium and zinc were lower in the patients relative to controls. Treatment with methotrexate elevated the zinc levels, but not zinc and selenium. Treatments with salazopyrin, corticosteroids, chloroquine, and non-steroidal anti-inflammatory drugs did not change the levels of any of the elements studied. The decrease in zinc and selenium levels and elevation in copper levels observed in the patients probably resulted from the defense response of organism and are mediated by inflammatory-like substances.     

ELEMENTS IN LIVER TISSUES OF BOWHEAD WHALES (BALAENA MYSTICETUS)

Livers from 20 bowhead whales taken in subsistence hunts at Barrow, Alaska, were analyzed for essential and non-essential elements. Concentrations of essential elements were similar to those found in other cetaceans. Non-essential element concentrations were generally comparable to other baleen whales and very low compared to most odontocetes. One deviation from this pattern was a relatively high level of hepatic cadmium that may be related to specific dietary factors of this krill-dependent species. No sex-related differences were found in element concentrations. Hepatic cadmium and mercury increased with animal length, and significant positive interelement correlations were found between copper/zinc and mercury/selenium. We found a mercury-toselenium ratio much lower (1:40) than the frequently reported ratio of one to one. The data suggest that further studies of the postulated mercurydetoxifying role of selenium are warranted.     

The effects of age and sex on seven elements of Sprague-Dawley rat organs

This study reports age-related changes in 7 element (iron, copper, zinc, manganese, mercury, cadmium and lead) concentrations in the liver, kidney and brain of male and female Sprague-Dawley rats from 1 to 364 days of age. Atomic absorption spectrometry was used for the measurements. Copper, mercury and cadmium in the male and female kidneys increased from weaning until 127 days of age, as did iron concentrations in the female liver and kidney. After 127 days, especially, the copper concentration in the female kidney and cadmium concentration in the male and female kidney increased further. Consistent and statistically significant (P less than 0.05) sex differences in element concentrations were found for three elements (iron, copper and zinc). Except for the zinc concentration in the liver from 50 to 72 days, iron (in liver and kidney), zinc (in kidney) and copper (in liver, kidney and brain) concentrations in female rats during the adult stage, were all higher than those of male rats. Isolated differences for other elements (manganese, mercury and cadmium) were also found. The data will be helpful when setting up long-term animal investigations of the biological effect of elements.     

Quantification and Comparison of Soil Elements in the Tibetan Plateau Kaschin-Beck Disease Area

The prevalence rate of Kaschin-Beck disease (KBD) in most parts of China is currently decreasing, but the disease is still active and severe on the Tibetan Plateau. Soil samples including the surface layer (0–20 cm) and the subsurface layer (20–40 cm) in the cultivated and natural soil profiles were collected, and the mechanical composite and total concentration of arsenic, cobalt, copper, iron, mercury, manganese, molybdenum, selenium, and zinc were determined. Concentrations of arsenic, iron, manganese, copper, and selenium in the surface soil were lower than those in the subsurface soil. The same was true of physical clay in the soil profiles. However, there were no significant differences between the different soil layers. The concentrations of selenium, molybdenum, and mercury were somewhat lower compared with the average concentrations of soils in China. Deficiencies of molybdenum and selenium both play a critical role in occurrence of KBD, but whether or not soil mercury at a low level contributes to KBD is still unclear. A correlation analysis of soil elements showed that there is a positive correlation between iron, cobalt, and manganese due to their similar chemical characteristics. Selenium concentrations in soil as well as the physical clay and iron descend with the deterioration of KBD, but mercury concentrations in soil ascend with the aggravation of the disease. The results show that selenium deficiencies greatly influence the disease, and a deficiency of molybdenum is likely another important factor in inducing KBD. Moreover, determining whether low levels of soil mercury contribute to KBD should be investigated in the future.     

Acrodermatitis enteropathica

We report on the successful use of repeated hair analyses over three decades to monitor zinc and copper status in two siblings with Acrodermatitis enteropathica who were treated with oral zinc sulfate beginning in 1975. Furthermore, we report for the first time that analysis of zinc in hair over a 30-yr period allows for the identification of individuals who might be heterozygous carriers of this autosomal recessive disease and who, therefore, would be expected to have hair zinc levels intermediate between normal, healthy individuals and those with Acrodermatitis enteropathica. Zinc treatment of the two patients with Acrodermatitis enteropathica resulted in remission of the signs and symptoms of the disease within the first month of therapy. However, any short-term interruption (typically, 7-10 d) in oral zinc resulted in an almost immediate relapse, with the reappearance of the skin lesions. We also document the inverse relationship that exists between zinc and copper through analysis of these metals in the scalp hair from the two patients, thus providing a tool for ensuring adequate copper intake in patients taking relatively high doses of zinc over a long period.     

Zinc,cadmium, mercury and selenium in polar bears (Ursus maritimus) from Central East Greenland

Muscle, liver, and kidney tissues from 38 polar bears (Ursus maritimus) caught in the Scoresby Sound area, Central East Greenland, were analysed for zinc, cadmium, mercury and selenium. In general, cadmium concentrations were low in muscle, liver and kidney tissue, with geometric means (g.m.) of 0.022 (range: <0.015–0.085), 0.841 (range: 0.092–3.29) and 13.1 (range: 1.04–115) g Cd/g wet weight (ww) respectively. This finding can be explained by low cadmium levels in the blubber of ringed seals. The concentration of mercury in muscle tissue was low (g.m. 0.071; range: 0.039–0.193 g Hg/g ww), whereas concentrations in liver and kidney tissue were relatively high (liver: g.m. 7.87; range: 1.35–24.8 g Hg/g ww, and kidney: g.m. 15.2; range: 1.59–66.6 g Hg/g ww). Mercury and cadmium were positively correlated with age in liver and kidney. Zinc was positively correlated with age in kidney, and selenium was correlated with age in liver. Contrary to other marine mammals, polar bears had higher mercury levels in the kidneys than in the liver. In all three tissues polar bears had significantly lower cadmium levels than ringed seals from the same area. Mercury levels were likewise significantly lower in the muscle tissue of polar bears than in ringed seals, whereas levels in the liver and kidney were significantly higher. The previous geographic trend for cadmium and mercury found in Canadian polar bears could be extended to cover East Greenland as well. Hence cadmium levels were higher in Greenland than in Canada, while the opposite was the case for mercury. Greenland polar bears had higher mercury and cadmium contents in livers and kidneys than polar bears from Svalbard. The mercury levels in muscle and liver tissue from polar bears from East Greenland were twice as high as found in bears from western Alaska, but half the levels found in northern Alaska. Cadmium and zinc were partially correlated in kidney tissue, and this was found for mercury and selenium as well. Cadmium and zinc showed molar ratios close to unity with the highest concentrations occurring in kidney tissue, while the levels of zinc exceeded cadmium in muscle and liver tissue by up to several decades. Mercury and selenium showed molar ratios close to unity in liver and kidneys.     

Changes in trace element concentrations in hair of growing children

Head hair concentrations of zinc, copper, manganese, and iron from a total of 418 subjects (154 male and 264 female) aged between 6 mo and 20 yr were measured mainly with flameless atomic absorption spectrophotometry. Only zinc analysis of a part of the female samples (n=140) were analyzed with inductively coupled plasma-atomic emission spectrometry. The two analytical methods showed close agreement. The mean concentration of copper and manganese were significantly higher in male subjects than in female subjects. The trace element concentrations in hair varied with the subject’s age. Zinc concentration in hair decreased from 6 mo to 14 yr in the male subjects and decreased from 6 mo to 12 yr in the female subjects. Then, the concentrations increased gradually to 20 yr in the both sexes. Age-dependent variations of copper and manganese concentrations in hair showed similar trends to those of zinc. The results of this study suggest that a higher concentration in the diet of these trace elements may be required for growing children, especially in the period of adolescence.