Evaluation of the use of human hair for biomonitoring the deficiency of essential and exposure to toxic elements

Monitoring the nutritional status of essential elements and assessing exposure of individuals to toxic elements is of great importance for human health. Thus, the appropriate selection and measurement of biomarkers of internal dose is of critical importance. Due to their many advantages, hair samples have been widely used to assess human exposure to different contaminants. However, the validity of this biomarker in evaluating the level of trace elements in the human body is debatable. In the present study, we evaluated the relationship between levels of trace elements in hair and whole blood or plasma in a Brazilian population. Hair, blood and plasma were collected from 280 adult volunteers for metal determination. An ICP-MS was used for sample analysis. Manganese, copper, lead and strontium levels in blood varied from 5.1 to 14.7, from 494.8 to 2383.8, from 5.9 to 330.1 and from 11.6 to 87.3 microg/L, respectively. Corresponding levels in hair varied from 0.05 to 6.71, from 0.02 to 37.59, from 0.02 to 30.63 and from 0.9 to 12.6 microg/g. Trace element levels in plasma varied from 0.07 to 8.62, from 118.2 to 1577.7 and from 2.31 to 34.2 microg/L for Mn, Cu and Sr, respectively. There was a weak correlation (r=0.22, p<0.001) between lead levels in hair and blood. Moreover, copper and strontium levels in blood correlate with those levels in plasma (r=0.64 , p<0.001 for Cu) and (r=0.22, p<0.05 for Sr). However, for Cu, Mn and Sr there was no correlation between levels in hair and blood. Our findings suggest that while the idea of measuring trace elements in hair is attractive, hair is not an appropriate biomarker for evaluating Cu, Mn and Sr deficiency or Pb exposure.     

Wastewater treatment from toxic metals by flotoextraction

Photoextraction of Ni(II) and Cu(II) ions has been investigated at pH 3-9.3 using potassium oleate and triethanolamine as collecting agents and octane, decane, and decanol as an organic phase. The maximum extraction rate of the specified ions amounts to 72 and 52% respectively. All possible structures of sublates were analyzed using data of IR-spectroscopy.     

Effects of toxic metals and chemicals on biofilm and biocorrosion

Microbes in marine biofilms aggregated into clusters and increased the production of extracellular polymeric substances (EPS), by over 100% in some cases, when the seawater media containing toxic metals and chemicals, such as Cd(II), Cu(II), Pb(II), Zn(II), AI(III), Cr(III), glutaraldehyde, and phenol. The formation of microbial cluster and the increased production of EPS, which contained 84-92% proteins and 8-16% polysaccharides, accelerated the corrosion of the mild steel. However, there was no quantitative relationship between the degree of increased corrosion and the toxicity of metals/chemicals towards sulfate-reducing bacteria, or the increased EPS production.     

Human exposure to heavy metals in East Greenland II lead

The concentration of lead in 175 blood samples originating from the district of Angmagssalik, East Greenland and 130 from Aarhus, Denmark, has been determined. Both Greenland and Danish males had significantly higher (5%) blood lead than females (Eskimoan males 14.8 μg Pb/100 ml, females 12.8 μg Pb/100 ml; Danish males 10.5 μg Pb/100 ml, females 7.7 μg Pb/100 ml). For Danes living temporarily in Greenland the values were: males 10.5 and females 10.2 μg Pb/100 ml.Eskimos of both sexes were found to have higher blood lead values than Danes living in the same area. Danish males from Greenland and Denmark were not found to be different, whereas Danish women living in Greenland had a significantly higher (5%) mean value that women living in Denmark. In the Eskimo group, but not in the Danish, a weak, positive, but significant age correlation was found. 4 samples of Eskimo origin exceeded 35 μg Pb/100 ml accepted in the EEC as a maximum value for non-occupationally exposed persons. When re-examined 5 months later, all values were below this limit.The influence of eating habits (local or imported food) and smoking habits was tested, but not found to influence the blood lead concentration.The results have confirmed that blood lead levels in Greenland are comparable to those found in European industrialized areas. The reason for the unexpected high level in the arctic area with minimum car driving and industry remains to be clarified.     

Human exposure to heavy metals in East Greenland I mercury

The concentration of mercury in 178 blood samples and 32 hair samples from the Angmagssalik district in East Greenland has been determined.For Greenlanders mercury concentrations are highly dependent on the amount of seal eaten. In the most heavily exposed group (eating more than six meals of seal per week), a significant positive correlation between blood mercury and age was demonstrated. No differences according to sex were demonstrated when the mean values were corrected for influence of age. In the most heavily exposed group, a mean value of 62.5 μg Hg/l was found, while in the group eating 1 meal of seal or less per week, the mean value was 22.2 μg Hg/l. In the control group consisting of Danes living temporarily in the district, the mean blood mercury concentration was 5.8 corresponding to the fact that they eat seal only occasionally.Hair mercury concentrations were found to correlate well with blood mercury concentrations (r = 0.9222). The hair/blood ratio was estimated to 289.It is concluded that the present relatively high mercury exposure in Greenland does not excert any immediate risk of intoxication to the adult population, but supplementary investigation on fetal exposure is needed.     

Market survey on toxic metals contained in tattoo inks

Tattooing practice is adopted worldwide and represents an important socio-cultural phenomenon, but, the injection into the skin of coloring agents as metals might pose a risk for allergies and other skin inflammations as well as for systemic diseases. In this context, 56 inks for tattooing purchased from 4 different supply companies were analyzed for metal concentration. Aliquots of pigments were microwave digested by nitric acid, fluoridric acid and hydrogen-peroxide and Al, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Sr and V were quantified by sector field inductively coupled plasma mass spectrometry. Limits of quantification varied from 0.07 ng/ml (Cd) to 10 ng/ml (Al and Fe); recoveries ranged from 92% (Cd and Sb) to 109% (Sr); within- and between-day precisions were 3.2% and 4.67% on average.The relative contribution of metals to the tattoo inks composition was highly variable between brands and colors, even in pigments with the same base color. Elements found as the main components of inks were as follows (in µg/g): Al, 1.59–5893; Ba, 0.058–1226; Cu, 0.076–31,310; Fe, 0.717–88,443; Sr, 0.174–36.4. Toxic metals as Cd, Mn, Pb, Sb and V were over the 1 µg/g in a few cases, while Hg was in traces. Among the allergenic metals, Cr was the highest (0.315–147 μg/g), followed by Ni (0.037–9.59 μg/g) and Co (0.0028–6.43 μg/g) then. On 56 tattoo inks, Cr, Ni and Co exceeded the safe allergological limit of 1 µg/g in 62.5%, 16.1% and 1.8% of cases, respectively.     

Spatial heterogeneity of personal exposure to airborne metals in French urban areas

The spatial distribution of urban population exposures to ambient air particles was investigated as part of the Genotox'ER study conducted in four metropolitan areas (Grenoble, Paris, Rouen and Strasbourg) in France. In each city, 60 to 90 non-smoking adult and children volunteers were selected. Subjects lived in three different urban sectors: one highly exposed to traffic emissions, one influenced by local industrial sources, and a background urban environment. The Harvard Chempass multi-pollutant personal sampler was used to sample PM10 and PM2.5 particles during 48 h during two different seasons ('hot' and 'cold'). The elemental composition of the filters was analysed by Particle-Induced X-ray Emission (PIXE). Sixteen elements were found to be over the method detection limits: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb. The relative concentrations of elements of crustal origin (Si, Al, Ca) were higher in the coarse fraction of PM10 filters, while elements associated with combustion processes (traffic emissions or industrial combustion) presented higher relative concentrations in the PM2.5 fraction (S, Ni, V, Pb). Spatial heterogeneity of elemental exposures by urban sector is substantial for some metals of health concern, with 20% to 90% greater exposure values, on average, in the traffic proximity or industrial sectors, compared to the background sector, for Fe, Zn, Cu, V and Cr. This spatial heterogeneity should not be overlooked in epidemiological or risk assessment studies.     

Criteria for the definition of reference values for toxic metals.

Two types of selection are used to identify subjects who make up reference groups: 'a posteriori' selection starting from a large number of subjects who are then subsequently selected and 'a priori' selection wherein the group to be examined is defined on the basis of preestablished criteria. The main variability factors are biological and those depending on the modalities of selection of groups and determination of the analysis. The nature of the element is also particularly important, i.e. whether an essential element must be considered only a micropollutant or whether it should be considered essential and at the same time a micropollutant. In addition two other factors which play an important role are the temporo-spatial modifications induced by natural or anthropogenic phenomena which influence the modality and degree of exposure in man. Two criteria are generally used in the production of reference groups: exclusion/inclusion and partitioning criteria. While in clinical chemistry the health status represents an important exclusion factor, in the case of metals, the environmental conditions and the function of organs and apparatuses involved in the toxicokinetics of metals can be considered as main criteria. All the other variables such as sex, age, life-style are partitioning criteria and enable us to obtain reference values for more and more homogeneous subgroups.     

Scalp hair analysis as a tool in assessing human exposure to heavy metals (S. Domingos mine, Portugal)

Hair samples from the scalp were used in a preliminary assessment of heavy metals exposure (As, Cd, Cr, Cu, Mn and Zn) of the human population living near an abandoned cupric pyrite mine (Mina de S. Domingos, Southeast Alentejo, Portugal). In parallel with the collection of hair samples, individuals from two different communities at the South and North of the mine area answered a questionnaire designed to obtain information about potential exposure pathways to these elements. The questionnaire allowed data collection about the most frequently consumed foodstuffs, drinking water sources, smoking habits, alcohol consumption and health condition. Higher concentrations, and subsequently higher ranges, of Cd, Cu and As were recorded in individuals living near the mine (MSD group), in opposition to individuals living several kilometers apart. Additionally, the concentrations recorded in the hair of some individuals from the MSD group were above the reference values for non-exposed individuals, suggesting their enhanced exposure. However, no significant differences were found for the average concentration of these elements between villages. Individuals from the CP and SC groups presented significantly higher concentrations of Zn and Mn in scalp hair. These results were in agreement with the concentrations of these elements recorded in soil samples. The water supplies of the area do not seem to be potential sources of trace elements for human beings. In opposition, individuals that frequently consume milk and cheese obtained from cattle that usually breeds in the area presented significantly higher concentrations of As and Mn in their scalp hair. Our results suggest that the population of S. Domingos mine area and neighbour localities may be exposed to some of the elements analysed namely Mn and Zn. The most likely exposure pathways seemed to be animal foodstuffs, however, a more detailed analysis of these products, as well as garden vegetables and fruits, should be performed.     

Influence of toxic metals on the repression of carbonaceous oxygen demand

Toxic metals like lead, bismuth, mercury and zinc-aranyl have been found to repress the carbonaceous oxygen demand. The biological seed was developed from trade waste of Glaxo Laboratories. Three concentrations: 5, 10 and 15 mg 1⁻¹ of the metals were used to observe repression of carbonaceous oxygen demand of amino acid, methionine, used as substrate. Rate constants, ratios of (t/y)^1.3 and COD: BOD were computed.     

Speedy technique of chromatographic determination of toxic metals in drinking water

We have developed a simple fast technique of chromatographic determination of toxic metals Cu. Cd, Co, Ni, Zn, Hg, and Pb in drinking water using thin layer chromatography. The metals were separated in the form of their complexes with dithizone and then photometric detection of obtained spots was carried out.     

Removal of toxic metals from aqueous solutions by layered double hydroxides

The article has investigated the possibility of using layered double hydroxide intercalated by diethylenetriaminepentaactetic acid for the removal of toxic metals from aqueous solutions. It has been shown that sorption of Ni(II), Co(II), and Pb(II) from aqueous solutions on the indicated sorbent is determined by several mechanisms of sorption: complexation, ionic exchange and precipitation of metal hydroxides. Comparative research of the efficiency of removing toxic metals by carbonate and chelate forms of sorbents was conducted.     

Prevalence and predictors of exposure to multiple metals in preschool children from Montevideo, Uruguay

The extent of children's exposure to multiple toxic metals is not well described in many developing countries. We examined metal exposures in young children (6-37 months) from Montevideo, Uruguay and their mothers (15-47 years) participating in a community-based study. Hair samples collected from 180 children and their mothers were analyzed for: lead (Pb), cadmium (Cd), manganese (Mn), and arsenic (As) concentration using inductively coupled plasma-mass spectrometry (ICP-MS). Median metal levels (μg/g) were: Pb 13.69, Mn 1.45, Cd 0.17, and As 0.09 for children and Pb 4.27, Mn 1.42, Cd 0.08, and As 0.02 for mothers. Of the child and maternal samples, 1.7% and 2.9% were below the limit of detection (LOD) for Cd, and 21.3% and 38.5% were below the LOD for As, respectively. Correlations between maternal and child levels ranged 0.38-0.55 (p < 0.01). Maternal hair metal levels were the strongest predictors of metal concentrations in children's hair. Girls had significantly lower As levels than boys (p < 0.01) but did not differ on other metals. In addition, in bivariate logistic regressions predicting the likelihood that the child would be exposed to multiple metals, hemoglobin < 10.5 g/dL (OR = 2.12, p < 0.05), blood lead (OR = 1.17, p < 0.01), and the mother being exposed to two or more metals (OR = 3.34, p < 0.01) were identified as significant predictors of increased likelihood of multiple metal exposure. Older child age (OR = 0.96, p < 0.05), higher maternal education (OR = 0.35, p < 0.01), and higher number of household possessions (OR = 0.83, p < 0.01) were significantly associated with decreased likelihood of multiple metal exposure. Preschool children in Uruguay are exposed to multiple metals at levels that in other studies have been associated with cognitive and behavioral deficits. Sources of exposure, as well as cognitive and behavioral consequences of multiple metal exposure, should be investigated in this population.     

Polarography and voltammetry in studies of toxic metals in man and his environment.

A brief introduction on sources, occurrence and fate of some toxic trace metals found in the natural environment is followed by a discussion of general methodological aspects from the trace chemical viewpoint. The versatile, significant and specific potentialities of advanced polarographic and voltammetric methods are compared with relevant non-electrochemical alternatives. They are subsequently demonstrated by a survey on representative applications, results and findings on problems from all types of environmental compartments and food chains to man, with emphasis on the toxic trace metals Cu, Cd, Hg, Pb, and also in certain matrices for Zn, As, Se, Tl and Bi. A final section is devoted to the particular potentialities of the electrochemical approach for speciation studies in natural waters at realistic trace levels of the dissolved toxic metals, e.g. Zn, Cd and Pb.     

Exposure to toxic agents alters organic elemental composition in human fingernails

Background and objective:

The human fingernail plate is highly keratinized. The keratin structure is held together by disulfide bonds. The organic elements sulfur and nitrogen occur almost exclusively in amino acids of the nail plate. This study analyzed whether occupational exposure to harmful chemical agents alters the organic elemental composition in fingernails.

Subjects and methods:

Participants were 71 occupationally exposed workers (49 hairdressers, 22 painters) and 49 unexposed controls. Aspects of exposure were assessed by questionnaire. Nail clippings of index and little fingers were analyzed for sulfur (S), nitrogen (N), carbon (C), and hydrogen (H) contents, using an automatic elemental analyzer (Vario EL III, Elementar Analysensysteme, Hanau, Germany). C/N, N/S, and C/S ratios were calculated. Reliability of elemental measurements was tested in a subset.

Results:

Reliability analysis of elemental measurements showed a very good agreement. Both painters and hairdressers displayed in their fingernails significantly lower percentages of sulfur, but higher percentages of carbon than unexposed controls. A trend was observed in that sulfur content was lowest in those hairdressers who reported structural changes in their fingernails. As a consequence, the C/S and N/S ratios were significantly increased in both exposed groups.

Conclusion:

The occupational use of harmful substances leads to decreased sulfur levels in the exposed persons, probably due to diminution of sulfur-rich proteins in the nails, resulting from destruction of disulfide-bonds by alkaline and acid groups. Thus, the C/S ratio seems to be a useful indicator for the amount of damage of nail protein by harmful agents.     

Use of human nails as bio-indicators of heavy metals environmental exposure among school age children in Kenya

Metal pollution and its health effects present a challenge currently facing the developing countries. Metal poisoning is usually difficult and expensive to assess or screen in these countries due to limited resources, which means that policies, guidelines, regulations and institutional managements are limited. Hair and nail as biopsy materials were suggested as more attractive biomarkers in assessing heavy metals environmental exposure. This paper deals with quantitative determination of lead (Pb), cadmium (Cd), calcium (Ca), zinc (Zn), and iron (Fe) in fingernails of children (n=200) in urban and rural areas using atomic absorption spectrometry. Factors that were suspected to influence the accumulation of Pb and Cd in children were obtained through a questionnaire. The mean levels of heavy metals in children in urban areas were found to be higher (27.5+/-1.8 microg/g Pb and 0.73+/-0.08 microg/g Cd) than in rural areas (19.7+/-0.9 microg/g Pb and 0.44+/-0.06 microg/g Cd). The difference was significant (P<0.05; DF=168, t-test). Other factors that were found to have significant influence were socio-economic background, health conditions, dietary habits and environmental risk exposure. The results also showed that the school location has more influence on the heavy metals level than the area of residence. The children in a school near the highway were found to have a mean of 34.4+/-3.5 microg/g Pb as compared to those who lived near the highway (31.6+/-2.8 microg/g Pb), however the difference was not significant (P>0.05), suggesting a common source of contaminants in the areas. The correlation results also indicated that a high level of Pb in the nail influenced negatively Zn and Fe but not Ca levels (R=-0.256 Zn; -0.188 Fe) while high levels of Cd had a negative relationship with Fe only (R=-0.241). The association of toxic metals in the nails of children with environmental exposure, and nutritional status implies that policies and actions to reduce heavy metal levels must be implemented and reinforced to address the health issues affecting children and by extension the general public in this country.     

Passive reduction of human exposure to indoor ozone

Reactive building materials offer an opportunity to provide indoor air cleaning with minimal energy use. Laboratory and test house experiments provide evidence that indoor ozone concentrations can be diminished by activated carbon (AC) and unpainted gypsum wallboard (GWB) panels. These two materials are highly reactive with ozone and produce few byproducts. When measured in a 14.2 m³ stainless-steel chamber, the mean deposition velocities to the materials were 5.3 m h^-1 for AC and 2.4 m h⁻¹ for GWB for a variety of airflow and relative humidity conditions. The ozone decay rates for both the materials were also measured in an unoccupied 34.5 m³ bedroom under various mixing conditions. In this case, ozone removal increased relative to background by 27–100% with a 4.4 m² panel of a reactive material placed on one wall of the bedroom. The ozone decay rate for the bedroom increased over background by approximately 2–3 h⁻¹ for GWB and 2–7 h⁻¹ for AC. Application of a mass balance model for a typical home demonstrates that effectiveness for ozone removal depends weakly on the air exchange rate and strongly on the panel material, panel area, and mixing conditions. An ozone removal effectiveness of over 80% is possible with sufficient panel area and positioning that provides elevated air speeds near the panels.