Metals In Hair Research Articles

The role of heavy metals and polychlorinated biphenyls (PCBs) in the oncogenesis of head and neck tumors and thyroid diseases: a pilot study

Previous literature has highlighted the mechanisms of molecular toxicity induced by substances such as arsenic, cadmium, chromium, nickel, lead, barium and PCBs. The research was carried out on 20 volunteers, all the patients gave their consent to the research: the aim of the study was to evaluate the presence of metals and PCBs in these different matrices (blood and hair), correlating the biochemical data to pathological conditions present, and also to the area in which patients resided. Various quantitative determinations were carried out on samples of blood and hair for 14 heavy metals and on blood samples for 12 PCBs. For the 11 patients the results indicated that blood levels for half of the 14 displayed heavy metals measured considerably higher compared to the reference values, whilst the levels measured in hair evidenced some positive values significantly higher than the maximum reference. Of the 12 PCBs assayed in blood some showed higher positive values compared to the maximum tabular reference (although there is no clear reference quantified in the WHO-2005 report). In the 9 healthy patients heavy metals in the blood were within the expected target range, with those showing positive results (≤ 3 out of 14 heavy metals for each patient) having values only slightly higher than the reference maximum. The levels of 14 heavy metals measured in hair were below thresholds, and levels for the 12 PCBs measured in blood showed negativity or positivity with values close to the minimum benchmarks. The analyses carried out on biological matrices have uncovered important and significant differences between healthy and unhealthy subjects, both qualitative and quantitative differences with respect to heavy metals and PCBs. All patients with head and neck cancer enlisted for the study had heavy metal and PCB blood levels at least twice the maximum reference level. The levels of heavy metals in hair were at least double the maximum reference. In contrast, all healthy volunteers enrolled showed no significant levels for either metals or PCBs.

Association Between Chronic Exposure to Tobacco Smoke and Accumulation of Toxic Metals in Hair Among Pregnant Women.

Tobacco smoke contains various toxic heavy metals that individuals are exposed to when they smoke. Despite the presence of heavy metals in tobacco smoke, the relationship between smoking and the accumulation of toxic metals in pregnant women after long-term exposure remains under discussion. We examined the association between long-term exposure to tobacco smoke and the accumulation of toxic metals in the hair of female participants. Our study recruited 252 women from the Shanxi and Hebei provinces of Northern China; these participants were self-reported non-active smokers, and had previously delivered healthy babies without birth defects. Scalp hair was collected and analyzed for nicotine and cotinine and five potentially toxic metals (specifically, silver, chromium, cadmium, mercury, and lead). Our results showed significant positive correlations between cotinine and four metals, including silver (r = 0.369, p < 0.001), cadmium (r = 0.185, p < 0.01), mercury (r = 0.161, p < 0.05), and lead (r = 0.243, p < 0.001). Significant positive correlations were also found between nicotine and three metals-specifically silver (r = 0.331, p < 0.001), cadmium (r = 0.176, p < 0.01), and lead (r = 0.316, p < 0.001). A logistic regression model showed significant associations between cotinine and potentially toxic metals including mercury, silver, and lead (with or without adjusting for potential confounders). We thus conclude that long-term passive smoking could potentially increase the exposure level of toxic metals including lead, silver, and mercury in our study, which are especially harmful for pregnant women and their unborn fetus.

Health Risk Assessment of Trace Metals in Various Environmental Media, Crops and Human Hair from a Mining Affected Area.

Long term exposure to trace metals in various media is of great concern for people living in known pollution sources, such as mining and industrial activities. Health risk assessment and human hair analysis can provide important information for local environmental management. Information on distribution characteristics of trace metals in soil, water, sediment, air, local crops, and human hair from a typical mining area in southern China was collected. Results show there exists severely trace metal contamination in soil, sediment, and air. Arsenic and Pb contents in the local children’s hair are higher than the upper reference values, and the accumulation of residents’ hair trace metals shows great correlation with the ingestion and inhalation pathways. Arsenic contributes 52.27% and 58.51% to the total non-cancer risk of adults and children, respectively. The cancer risk of Cd in adults and children are 4.66 and 3.22 times higher than the safe level, respectively. Ingestion exposure pathway of trace metals largely contributes to the total non-cancer and cancer effect. The metals As, Cd, and Pb are major risk sources and pollutants that should be given priority for management, and ingestion pathway exposure to trace metals through soil and crops should be controlled.

Distribution of metal and metalloid elements in human scalp hair in Taiyuan, China

This study investigated the levels of metal and metalloid elements (As, Ca, Cd, Cr, Cu, Fe, Hg, Mg, Ni, Pb, and Zn) in scalp hair samples collected from 161 people of different age and gender groups living in the six districts of Taiyuan, an industrial city with rich coal reserve in Shanxi province in China. Levels of most elements in the hair were high in the 26–40 age groups and increased with the length of residence. Calcium, Cr, Mg, Ni and Zn levels in the females’ hair were significantly higher than those in the males’ (p < 0.05). Element levels in the hair didn’t have significantly differences between industrial and non-industrial districts because most of industry factories are in the upper wind position in Taiyuan, and contamination is prone to spread to non-industrial districts. The principal component analysis indicates that the main sources of these elements are mining activities, the neighboring stainless steel industry, and coal combustion. These results indicate that the industrial activities primarily contribute to the metal and metalloid pollution in Taiyuan, whereas numerous factors caused the metals accumulation in hair.

Effects of sex on the levels of metals and metalloids in the hair of a group of healthy Spanish adolescents (13 to 16years old).

Human biomonitoring can be a reliable tool to protect the health of the citizens of major urban environments. Human hair may be an invaluable specimen to determine chronic exposure to any environmental contaminant in an individual, especially in the young population. However, different factors including a lack of studies that have established reference values for metals and metalloids (trace elements) in human scalp hair make the use of this matrix controversial. A monitoring study was performed to establish possible normal or tentative reference values of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Pb, Sn, Ti, Tl and Zn in adolescents' (aged 13-16) hair who have lived since birth in Alcalá de Henares, Madrid region (Spain). Strict inclusion criteria were followed to study the effect of sex on the hair metal content, and the levels of the above contaminants were also studied in park topsoils from Alcalá de Henares. Scalp hair samples were collected from 96 healthy adolescents (28 boys and 68 girls), and reference values were calculated following the recommendations of the International Union of Pure and Applied Chemistry. The levels of Cd, Cu, Pb, Sn and Zn in hair of adolescents from Alcalá de Henares show a sex dependency, being significantly higher in female participants. Sex should be a factor taken into account when developing future reference values and hair metal content. Soil metal contamination was not correlated with the levels found in hair. To conclude, the values of metals and metalloids here analysed and discussed could be considered as tentative reference values for Spanish adolescents aged 13-16years living in the Madrid region, and may be used to identify the level of exposure of adolescents in this Spanish region to the various metals and metalloids.

Distribution and health risk assessment to heavy metals near smelting and mining areas of Hezhang, China.

Mining and smelting areas in Hezhang have generated a large amount of heavy metals into the environment. For that cause, an evaluative study on human exposure to heavy metals including Co, Ni, Cu, Zn, Cr, As, Cd, Pb, Sb, Bi, Be, and Hg in hair and urine was conducted for their concentrations and correlations. Daily exposure and non-carcinogenic and carcinogenic risk were estimated. Sixty-eight scalp hair and 66 urine samples were taken from participants of different ages (6-17, 18-40, 41-60, and ≥65years) living in the vicinity of an agricultural soil near mine and smelting areas. The results compared to the earlier studies showed an elevated concentration of Pb, Be, Bi, Co, Cr, Ni, Sb, and Zn in hair and urine. These heavy metals were more elevated in mining than in smelting. Considering gender differences, females were likely to be more affected than male. By investigating age differences in this area, high heavy metal concentrations in male's hair and urine existed in age of 18-40 and ≥66, respectively. However, females did not present homogeneous age distribution. Hair and urine showed a different distribution of heavy metals in different age and gender. In some cases, significant correlation was found between heavy metals in hair and urine (P>0.05 and P>0.01) in mining area. The estimated average daily intake of heavy metals in vegetables showed a great contribution compared to the soil and water. Non-carcinogenic and carcinogenic risk values of total pathways in mining and smelting areas were higher than 1 and exceeded the acceptable levels. Thus, the obtained data might be useful for further studies. They can serve as a basis of comparison and assessing the effect of simultaneous exposure from heavy metals in mining and smelting areas, and potential health risks from exposure to heavy metals in vegetables need more consideration.

Assessment of Typical Heavy Metals in Human Hair of Different Age Groups and Foodstuffs in Beijing, China.

Human hair of different age groups and foodstuff samples were collected in Beijing, China. The concerned metals—Cd, Cr, Pb, As, and Hg—were analyzed, and the metal levels in relation to age, gender, and dietary intake were further assessed. Results showed the highest level of the metals was shown by Pb, with an average concentration of 1.557 ± 0.779 mg/kg, followed by Cr (0.782 ± 0.394), Hg (0.284 ± 0.094), As (0.127 ± 0.078), and Cd (0.071 ± 0.032), following a decreasing order of Pb > Cr > Hg > As > Cd, which were all below the upper limit of normal values in China. The heavy metal concentrations varied greatly among different age groups, and higher concentrations for Cd, Cr, Pb, and As appeared in female hair, whereas higher Hg concentration were found in male hair, suggesting that age and gender were not crucial factors for assessing metal concentrations in human hair. The ingestion of cereals and vegetables were the main route by which heavy metals in the environment create hazardous health effects for local inhabitants, but the estimated metal intakes through food consumption were all lower than the proposed limit of Provisional Tolerable Weekly Intake (PTWI), indicating that heavy metals posed no health risks for the inhabitants. Furthermore, little relationship was found between metal intakes and the corresponding metal levels in hair. Nevertheless, the results of this study can be used to analyze the internal heavy metal burden in the resident population of Beijing area and can also serve as reference for further studies.

A cross sectional study of the relationship between the exposure of pregnant women to military attacks in 2014 in Gaza and the load of heavy metal contaminants in the hair of mothers and newborns

ObjectiveMetal contamination of humans in war areas has rarely been investigated. Weaponry’s heavy metals become environmentally stable war remnants and accumulate in living things. They also pose health risks in...

Accumulation of heavy metal in scalp hair of people exposed in Beijing sewage discharge channel sewage irrigation area in Tianjin, China.

Heavy metal concentrations in soil, wheat, and scalp hair exposed to Beijing sewage discharge channel sewage irrigation area (BSIA) in Tianjin were studied to evaluate the influence of sewage irrigation. Results showed that the continuous application of wastewater has led to an accumulation of heavy metals in the soil, with 55.2 and 8.62% of soil samples accumulating Cd and Zn, respectively, at concentrations exceeding the permissible limits in China. Concentrations of heavy metals in wheat grain from BSIA were higher than these from the clean water irrigation area by 63.2% for Cd, 3.8% for Cu, 100% for Pb, 6.6% for Zn, and 326.7% for Cr. The heavy metal bioaccumulation factor (BAF) of wheat/soil in BSIA showed the following order: Zn > Cd > Cu > Pb > Cr. Interestingly, these accumulation of heavy metals in soil after sewage irrigation could increase the migration ability of heavy metals (particularly Zn and Cd) from soil to wheat. Mean concentrations of heavy metals in the hair of residents followed the decreasing trend of Zn > Cu > Pb > Cr > Cd, which were higher than the control area by 110.0% for Cd, 20.0% for Cu, 55.9% for Zn, 36.6% for Pb, and 64.6% for Cr. Concentrations of heavy metals in male human hair in BSIA were higher than those of females. And the concentrations of heavy metals except for Pb in human hair increased with their increasing ages. The heavy metal BAF values of wheat/soil in BSIA showed the trend of Zn (98.0057)>Pb (7.0162)>Cr (5.5788)>Cu (5.4853)>Cd (3.5584); heavy metals had obvious biological amplification from wheat to human hair. These results indicated that local population health was potentially exposed to the heavy metal risk via wheat consumption.

Bioaccumulation and Correlation of Heavy Metals in Human Hairs From Urban and Rural Areas of Chongqing

In the present study, human hair samples were collected in Chongqing to detect the concentrations of heavy metals including Cd, Cu, Ni, Pb and Zn by flame atomic absorption spectrophotometry. Meanwhile, the relationship between the content of heavy metals and age, gender and smoking habits was also analyzed, and the potential sources of the heavy metals in human hair were understood through correlation analysis and principal component analysis. The results showed that the mean concentrations of Cd, Cu, Ni, Pb and Zn were 3.1, 24.3, 9.7, 42.8 and 209.6 μg·g-1, respectively in urban areas, while the mean contents were 0.9, 15.8, 5.6, 15.2 and 173.4 μg·g-1, respectively in rural area. The residents living in urban areas exhibited significantly higher concentrations than those in rural area, revealing the same heavy metal pattern with that in soils (t-test, P<0.01). No obvious trend was observed between the contents of heavy metals and age, except that the contents of Cu and Zn were increasing with the growth of age. Significantly higher concentrations of Cd and Pb were both observed in male hair and smokers than those in female and non-smokers, respectively in urban and rural areas (P<0.01). Similar correlation patterns among Cd, Cu, Ni and Pb were found both in urban and rural areas. According to principal component analysis, Cu, Ni and Pb contaminations had similar sources in urban areas, whereas Cd, Ni and Pb had similar sources in rural area.

Multiple Low‐Level Metal Exposure and Indicators of Weight and Height in Uruguayan Urban School Children

The contribution of chronic environmental lead and other toxic metal exposure to anthropometric status of children is unclear. Effects of multiple metal interactions at low levels of exposure are unknown. In this study, associations between concentrations of lead in blood, and of arsenic, cadmium, and manganese in hair, and indicators of weight and height status were examined in Uruguayan urban school children (n=290). Study recruitment, procedures and informed consent were approved by Institutional Ethical Committees. Fasting blood samples were collected, and lead in blood (BLL) was analyzed by GFAAS. Hair was cut close to the scalp with stainless steel scissors, from back of the head. Metals in hair were analyzed by ICPMS. Associations were examined by multifactor ANOVA and multiple regression analyses, with gender and tertiles of metal concentrations entered as factors into a single model, adjusted for serum ferritin corrected for C‐reactive protein. HAZ (height for age Z score), WAZ (weight for age Z score) and BAZ (body mass index for age Z score), were modeled separately. Children were 6–9 years old, 45% girls, non‐anemic, and with low iron reserves (median serum ferritin: 17.9 μg/L). Median Z scores of anthropometric measures were adequate (0.41, 0.70, 0.60, for HAZ, WAZ, BAZ, respectively), but with wide ranges between extreme values. Median (range) for BLL was 4.0 (0.8–13.2) μg/dL, and for hair metals: Mn 0.81 (0.06–25.7), As 0.052 (0.002–1.332), Cd 0.095 (0.005–0.8), μg/g. BLL was negatively associated with all 3 anthropometric Z scores (P≤0.003). Children at the lowest BLL tertile had higher mean Z scores than in each of the other tertiles (0.48 and 0.59 higher for HAZ; 0.77 and 0.60 for WAZ; 0.78 and 0.40 for BAZ). Hair Mn was positively associated with BAZ (P=0.017). Hair As tended to have a positive association with WAZ (P=0.0502). Exposure to low levels of lead may impair measures of anthropometric growth in children of school age. Interactions between low levels of combined metals exposure and anthropometric indices in children appear to be complex, and possibly related to nutritional status and other unknown factors.Support or Funding InformationNIEHS R21ES16523, R21ES019949

Study of trace metal imbalances in the blood, scalp hair and nails of oral cancer patients from Pakistan

Oral cancer is an important cause of cancer morbidity and mortality globally and exposure to trace metals alongside tobacco, alcohol and HPV are the important etiological factors in its development. Selected essential and toxic trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured in the blood, scalp hair and nails of oral cancer patients and counterpart controls by atomic absorption spectrometry. Mean concentrations of Cd, Ni and Pb were found to be significantly higher (p<0.05) and those of Cu, Fe and Zn were considerably lower in the blood, scalp hair and nails of the patients than the controls. Most of the metal concentrations exhibited higher dispersion and asymmetry in the blood, scalp hair and nails of the patients compared with the controls. The correlation study revealed significantly diverse relationships among the metals in blood, scalp hair and nails of both donor groups. Variations in the metal levels were also noted for various stages (I, II, III & IV) as well as the types (adenocarcinoma and squamous cell carcinoma) of oral cancer. Multivariate cluster analysis of the metal levels in the patients were also significantly dissimilar than the controls. The study evidenced considerably divergent variations in the metal levels in oral cancer patients in comparison with the controls.

Association of essential trace metals in maternal hair with the risk of neural tube defects in offspring.

The relationship between essential trace metals (ETMs) and the risk of neural tube defects (NTDs) is still unclear. One of the challenges is to evaluate the intake of ETMs of women during their early period of pregnancy. We proposed the hypothesis that an ETM deficiency in women during their early period of pregnancy is associated with an elevated risk of NTDs in offspring. We recruited 191 women with NTD-affected pregnancies (case group) and 261 women who delivered healthy infants (control group). Nine ETMs in hair sections grown during maternal early pregnancy were analyzed: iron (Fe), zinc (Zn), copper (Cu), cobalt (Co), manganese (Mn), chromium (Cr), nickel (Ni), molybdenum (Mo), and stannum (Sn). Information on maternal dietary habits were collected by questionnaire. We observed a significant decreasing trend in the dose-response relationships between the Ni and Mo concentrations in hair and NTD risks. A Zn deficiency was only associated with an elevated risk of spina bifida, and a Sn deficiency was only associated with anencephaly. The Ni and Zn concentrations in hair were positively correlated with the frequency of consumption of fresh green vegetables and fresh fruits, while the Zn concentration was also associated with fish or meat consumption. We concluded that maternal intakes of the four ETMs (Ni, Mo, Zn, and Sn) played an important role in the formation of NTDs in our study population, and that this intake is related to maternal dietary habits.Birth Defects Research 109:234-243, 2017.© 2016 Wiley Periodicals, Inc.

Hair biomonitoring and health status of a general population exposed to Nickel

An epidemiological cross-sectional study was conducted in a Greek population, being orally exposed to Ni via food consumption, in order to investigate possible health effects and to evaluate hair Ni concentration as a biomarker of exposure.The study population consisted of 139 men and 155 women, aged 25–69. Socio-demographics, lifestyle, dietary habits, occupational and medical history data were recorded through a personal interview. Hematological and biochemical examinations were conducted in blood specimens. Metals – Ni, Cr, Cd, Pb, Hg, Cu and Zn – were determined in hair samples. Women were characterized by higher Ni and Cu hair concentrations, while men by higher Cr and Hg. Factors affecting hair metal concentrations were identified to be dietary habits, consumption of local crops, occupation and smoking.Hair element content in the study population was comparable to the “reference ranges” reported in Europe, except for Ni, found higher in a fraction of our population. Men in the upper quartile of hair Ni distribution are at higher risk for abnormal high cholesterol, LDL, albumin and calcium, with odds ratios (OR) varying between 3.5 and 6.2. Accordingly, high hair Ni content in women is associated with abnormal glucose (OR=3.9), triglycerides (OR=3.1) and low abnormal sodium (OR=4.3).The study provides evidence of the suitability of hair analysis in assessing environmental exposure to Ni and supports the use of hair Ni content as a valuable and relatively inexpensive tool of biomonitoring, to identify people at risk for certain biochemical alterations.

Вміст важких металів у шерсті корів північно-східної біогеохімічної зони

The anthropogenic pollution of the environment in most cases connected with trace elements of heavy metals group. The effect of negative technogenic factors of the environment by interaction with the natural deficiency of essential microelements contributes to the appearing and spread of pathology of mineral metabolism among farm animals. The application of noninvasive methods for diagnosis of diseases of farm animals is a promising direction in veterinary medicine. The question of impact of the northern-eastern biogeochemical zone of Ukraine on the content of heavy metals in cows hair with consideration of lactation, keeping technology and colour hair samples is not researched enough. The research was conducted in the three farms of Chernihiv region (northern-eastern biogeochemical zone). The content of heavy metals was investigated by atomic emission spectrometry using Optima 210 DV. The materials the author’s own research to determine the status of the cow organism by noninvasive method in the northeastern biochemical zone of Ukraine concerning the content of heavy metals in different periods of lactation, keeping technology are introduced in the work. The content of Cadmium, Plumbum, Aluminum and Arsene in the hair of cows northeastern biogeochemical zone of Ukraine depending on the colour samples of hair (black, brown, white), keeping technology (loose, stable-pasture, stable) and period of lactation (55–65 days, 150–170 days) are investigated. The concentration of heavy metals in the hair of cows of the northeastern biogeochemical zone of Ukraine are: Cadmium – 0.03 ± 0.004 mg/kg, Plumbum – 0.70 ± 0.11 mg/kg, Aluminum – 16.78 ± 4.02 mg/kg, Arsene – 0.21 ± 0.05 mg/kg. In the hair of cows of the northeastern zone in 55–65 days of lactation the content of Cadmium is 0.04 ± 0.01 mg/kg, Plumbum – 0.83 ± 0.31 mg / kg, Aluminum – 15.79 ± 3.83 mg/kg, Arsene – 0.30 ± 0.14 mg/kg. In 150–170 days of lactation period the content of Cadmium is 0.04 ± 0.005 mg/kg, Plumbum – 1.25 ± 0.35 mg/kg, Aluminum – 22.34 ± 14.21 mg/kg and Arsene – 0.25 ± 0.07 mg/kg.

Heavy Metal and Trace Mineral Profile in Blood and Hair of Cattle Reared Around Industrial Effluent Contaminated Area

Heavy Metal and Trace Mineral Profile in Blood and Hair of Cattle Reared Around Industrial Effluent Contaminated Area

A simultaneous analysis method of polycyclic aromatic hydrocarbons, nicotine, cotinine and metals in human hair

Polycyclic aromatic hydrocarbons (PAHs), nicotine, cotinine, and metals in human hair have been used as important environmental exposure markers. We aimed to develop a simple method to simultaneously analyze these pollutants using a small quantity of hair. The digestion performances of tetramethylammonium hydroxide (TMAH) and sodium hydroxide (NaOH) for human hair were compared. Various solvents or their mixtures including n-hexane (HEX), dichloromethane (DCM) and trichloromethane (TCM), HEX:DCM32 (3/2) and HEX:TCM73 (7/3) were adopted to extract organics. The recoveries of metals were determined under an optimal operation of digestion and extraction. Our results showed that TMAH performed well in dissolving human hair and even better than NaOH. Overall, the recoveries for five solutions were acceptable for PAHs, nicotine in the range of 80%–110%. Except for HEX, other four extraction solutions had acceptable extraction efficiency for cotinine from HEX:TCM73 (88 ± 4.1%) to HEX:DCM32 (100 ± 2.8%). HEX:DCM32 was chosen as the optimal solvent in consideration of its extraction efficiency and lower density than water. The recoveries of 12 typical major or trace metals were mainly in the range of 90%–110% and some of them were close to 100%. In conclusion, the simultaneous analysis of PAHs, nicotine, cotinine, and metals was feasible. Our study provided a simple and low-cost technique for environmental epidemiological studies.

Authenticity, artifice, ideology: Heavy metal video and MTV’s ‘Second Launch’, 1983–1985

Abstract Music video scholars have identified a ‘second launch’ of MTV during 1983–1985, a period when, as Andrew Goodwin writes, ‘MTV programmed heavy metal with a vengeance’. My article expands on the research of Goodwin, Lisa Lewis, Carol Vernallis and others in exploring the question of why metal emerged during this particular MTV era in the wake of British-based new pop, which had dominated the ‘first launch’ of MTV since August 1981. Central to my research is a more nuanced analysis of the metal subgenres that dominated programming between 1983 and 1985 – videos that are quite distinct both from the non-realist British new pop of bands such as ABC, Ultravox and Duran Duran and from the ‘hair metal’ that proliferated in the late 1980s.

Levels of five metals in male hair from urban and rural areas of Chongqing, China.

Heavy metals were measured by flame atomic absorption in male hair from residents in urban and rural areas in Chongqing. The median values of the Cd, Cu, Ni, Pb and Zn were 2.90, 23.9, 9.31, 39.3 and 203μg/g in urban areas and 0.84, 13.4, 5.56, 14.5 and 169μg/g in rural area, respectively. The levels of Cd, Ni and Pb both in urban and rural areas lie at the high end of the worldwide figures. The differences in heavy metal distribution pattern indicated that there were more sources of Cd and Pb in urban areas. The levels of Cd were increasing along with the growth of age except for the aged people in urban areas, and no significant relationship was observed between the levels of the heavy metal and the age. It is noticed that the hair of smokers exhibited more heavy metal levels than that of non-smokers both in urban and rural areas. In addition, the hair metal levels of the smokers and non-smokers in urban areas were significantly higher than those in rural area, respectively. Significant pairwise correlations (p<0.01) were observed among Cd, Cu, Ni and Pb in rural area and only between Cu and Ni and between Pb and Ni in urban areas, indicating the elements in these two areas might originate from different sources. The elevated levels of Cd, Pb and Ni implied that the residents both in urban and rural areas might be at high risk of toxic metal exposure, especially for the children.

Evaluating the effect of age and area of residence in the metal and metalloid contents in human hair and urban topsoils.

Monitoring the levels of trace elements in hair can allow estimating the effects of the geographical location and also can provide a notion of the metal body burden. However, the use of human hair is controversial due to the different confounding factors that could affect the presence of trace elements in hair. As a result, a comprehensive monitoring study was performed in Alcalá de Henares, one of the major cities in the Madrid region, Spain. Trace elements have been monitored in urban topsoils and in human hair of two well-defined and healthy groups of population: children (6-9years) and adolescents (13-16years). The city was divided into four areas or zones with different characteristics to assess the possible effect of area of residence and age in the presence of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Pb, Sn, Ti, Tl and Zn in soils and hair. There is no current hypothesis that explains the possible effect of the area of monitoring in the distribution of Be, Cr, Ni, Sn and Ti found in these urban soils, maybe because urban soils receive high disturbance, and there are many factors involved. The presence of most of the trace elements monitored was significantly higher in the hair of the children population, except for Sn and Zn. This could be attributed mainly to dietary habits. Other factors influencing metal content in hair such as environmental factors would have had a minimal effect in the population groups here studied. Finally, none of the levels of trace elements studied in hair were significantly correlated with levels measured in the topsoils of public parks in Alcalá de Henares, with the exception of Pb in adolescent participants.