Concentrations of lead in blood, hair and saliva of German children living in three different areas of traffic density

Environmental tobacco smoke exposure is associated with increased levels of metals in children's saliva

BACKGROUND

Exposure to environmental tobacco smoke (ETS) has been associated with detectable levels of cotinine (a nicotine metabolite) in children's saliva. However, tobacco smoke also contains toxic and essential trace metals, including chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn).

OBJECTIVE

The current study examines whether there is a relationship between ETS exposure, as gauged by salivary cotinine, and salivary levels of these metals in a subset (n = 238) of children from the Family Life Project.

METHODS

Using inductively-coupled-plasma optical emission spectrophotometry, we measured levels of metals in saliva from children at ~90 months of age. Salivary cotinine was measured using a commercial immunoassay.

RESULTS

We found that Cr, Cu, Mn, and Zn were detected in most samples (85-99%) with lower levels of detection for Pb and Ni (9.3% and 13.9% respectively). There were no significant differences in any of the metal concentrations between males and females, nor were levels associated with body mass index, although significant differences in salivary Cr and Mn by race, state and income-to-needs ratio were observed. Children with cotinine levels >1 ng/ml had higher levels of Zn (b = 0.401, 95% CI: 0.183 to 0.619; p = 0.0003) and Cu (b = 0.655, 95% CI: 0.206 to 1.104; p = 0.004) compared to children with levels <1 ng/ml, after controlling for multiple confounders, including sex, race, BMI and income-to-needs ratio. Further, we show that children whose cotinine levels were >1 μg/L were more likely to have detectable levels of Pb in their saliva (b = 1.40, 95% CI: 0.424 to 2.459; p = 0.006) compared to children with cotinine levels <1 ng/ml, also considering confounders.

IMPACT STATEMENT

This is the first study to demonstrate significant associations between salivary cotinine and salivary levels of Cu, Zn and Pb, suggesting that environmental tobacco smoke exposure my be one source of increased children's exposure to heavy metals. This study also demonstrates that saliva samples can be used to measure heavy metal exposure, and thus serve as a non-invasive tool for assessing a broader range of risk indicators.

The role of lead and cadmium in deciduous teeth and saliva on dental caries in children residing in Tehran, Iran

BACKGROUND

Lead (Pb) and Cadmium (Cd) are important environmental contaminants. There is no biological monitoring of exposure to these heavy metals and their potential effect on dental caries in children in Tehran, Iran, a polluted megacity. Therefore, the present study investigated the potential association between Pb and Cd levels in primary teeth and saliva and dental caries.

METHODS

In a cross-sectional design, 211 children aged 6-11 years referred to Tehran University of Medical Sciences, School of Dentistry and residing in Tehran were examined. Pb and Cd levels of exfoliated primary teeth and stimulated saliva were determined by atomic absorption spectrophotometry (AAS). Dental caries prevalence was evaluated according to WHO criteria. Socioeconomic status, oral hygiene behavior, snacking frequency and salivary pH data were acquired as confounding factors. Frequency and percentages were reported for categorical variables, mean and standard deviation (SD) for continuous variables, and geometric mean for skewed continuous variables. A simple linear regression and Pearson correlation tests were used for statistical analyses. P-values < 0.05 were considered as significant.

RESULT

The mean (95 % confidence interval) Pb and Cd levels in teeth were 213.26 ppb (164.29-274.84) and 23.75 ppb (20.86-27.05), respectively. The mean Pb and Cd levels in saliva were 11.83 ppb (10.71-13.06) and 3.18 ppb (2.69-3.75), respectively. Furthermore, Pb and Cd in primary teeth and saliva were not associated (p > 0.05) with socioeconomic status, oral hygiene behavior and snacking frequency CONCLUSION: This study showed no association between Pb and Cd concentrations in primary teeth and in saliva with dental caries prevalence.

Levels of Toxic and Essential Elements and Associated Factors in the Hair of Japanese Young Children

There is growing concern regarding the effects of toxic element exposure on the development of children. However, little is known about the level of toxic elements exposure in Japanese children. The purpose of this study was to assess the concentrations of multiple elements (aluminum, cadmium, lead, calcium, copper, iron, magnesium, sodium, zinc) in the hair of 118 Japanese young children and to explore the factors associated with their element levels. The element concentration was analyzed by ICP-MS, and children's food and water intake were assessed by the questionnaire. Results showed that there were no large differences between the level of elements in the hair of Japanese children and those of children in other developed countries. Girls had significantly higher levels of aluminum, copper, and iron (p = 0.000, 0.014, and 0.013, respectively), and boys had a higher level of sodium (p = 0.006). The levels of calcium, iron, magnesium, and sodium in nursery school children were significantly higher than those in kindergarten children (p = 0.024, 0.001, 0.046, and 0.029, respectively). Multiple regression analyses with controlling the confounding variables showed significant negative associations of frequency of yogurt intake with aluminum and lead levels (p = 0.015 and 0.037, respectively). When the children were divided into three groups based on the frequency of yoghurt consumption, viz. L (≤once a week), M (2 or 3 times a week), and H (≥4 to 6 times a week) group, the mean aluminum concentration (µg/g) in the L, M, and H groups was 11.06, 10.13, and 6.85, while the mean lead concentration (µg/g) was 1.76, 1.70, and 0.87, respectively. Our results suggested the validity of hair element concentrations as an exposure measure of essential elements and frequent yogurt intake as a viable measure for protecting children from toxic elements. However, these findings will need to be confirmed in more detailed studies with larger sample sizes in the future.

Multi-matrix biomonitoring approach to assess exposure to metals and trace elements in the Lebanese population and associations with drinking water consumption

This study is the first attempt to assess exposure to metals and trace elements in subgroups of the Lebanese population using a multi-matrix biomonitoring approach. Concentrations of 11 metals and trace elements (aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), selenium (Se), uranium (U), zinc (Zn)) were measured in urine, hair and toenails. Biological levels were compared according to age, sex, smoking status, socioeconomic status, geographical area and drinking water source. While most urinary and toenail concentrations of metals and trace elements were not different between males and females, measured concentrations of several elements in hair were higher in females compared to males. Urinary concentrations of some metals (Al, Cu, Se and Zn) were higher in children compared to teenagers and adults. Hair and toenail concentrations of several elements (As, Cd, Pb, Mn, Se in hair and toenails plus Al, Fe in toenails) were also significantly higher in children compared to teenagers and/or adults. Smoking status had no influence on metal and trace element concentrations. Levels of Cd, Pb and Mn were also higher in samples from subgroups with lower economic status (Cd and Pb in the three matrices and Mn in hair and toenails). Very few correlations were identified between sources of drinking water and urine, hair, and toenail concentrations of metals and trace elements. However, a correlation was observed between hair and toenails levels of As, Cd and Pb. Overall, results highlight that a special attention should be given to metal and trace element exposure in this population (including Pb, As, Cd, Mn, and Se). It could be relevant to scale up this kind of investigation with a large human biomonitoring initiative in the Lebanese population in order to generalize results, and assess trends over time.

High lead level in the Alps in XIXth century, learning from the analysis of 138 historical hair stands

Analysis of hair is known to provide useful information about environmental and toxic exposures. Very little historical use has been made of this type of investigation. Here we study 138 human hair samples from 19th century in France. In order to examine the potential association between contamination and historical health impacts, we characterized contamination by 33 elements in a set of hair strands sampled during the last quarter of the 19th century in the Savoy region of France. After a selected washing step on 138 hair strands conserved at the Museum National d'Histoire Naturelle in Paris (France), we assessed the presence of inorganics by ICP/MS, and lead level was higher than values reported in literature. We then compared concentrations and distributions between women and men, sampling locations and crossing gender and geographical origin. Hair lead level was high throughout Savoy at the end of the 19th century: significantly higher for people living in towns or industrial valleys, and lower for those of countryside and mountains areas. Environmental and economic changes (industrialization and urbanization with water adduction and leaded paints), living habits (kitchenware, cosmetics, wine, and tobacco), and local features (mines exploitation, railroad development, and industrialized narrow valleys) could be envisaged for explaining the level of lead contamination. In the same period, the two main industrial valleys of Savoy (Maurienne and Tarentaise) had high rates of endemic goiter and cretinism and among the highest hair lead levels. Other lines of evidence will need to be explore to investigate a possible link between historical Pb exposure and goiter in the study area.

Salivary Lead Levels among Workers in Different Industrial Areas in the West Bank of Palestine: a Cross-Sectional Study

Saliva is a biofluid that can easily be obtained and used for biomonitoring lead levels in occupationally and environmentally exposed individuals. The aims of this study were to determine salivary lead levels among workers in different industrial areas in the West Bank of Palestine and investigate the association between sociodemographic and occupational characteristics of the workers and their salivary lead levels. Salivary samples were obtained from workers in different industrial areas in metal-free polyethylene tubes. The samples were analyzed for their lead contents using a pre-validated inductively coupled plasma-mass spectrometric method. A total of 97 salivary samples were analyzed. The median salivary lead level was 1.84 μg/dL an IQR of 5.04 μg/dL. Salivary lead levels were significantly higher in workers who were 40 years and older (p value = 0.031), had 3 children or more (p value = 0.048), worked in repair workshops (p value = 0.012), worked in industrial areas for 20 years or more (p value = 0.048), did not consume fruits on regular basis (p value = 0.031), and smoked for 30 years or more (p value = 0.013). Multiple linear regression showed that smoking of 30 years old or more was a significant (p value < 0.001) predictor of higher salivary lead levels. Salivary lead levels among workers from different industrial areas of the West Bank were comparable to those occupationally exposed to lead in more industrialized and urbanized areas of the world. Smoking was a predictor of higher salivary lead levels.

Lead exposure in dogs fed game meat and offal from culled invasive species in El Palmar National Park, Argentina

This is the first field study to evaluate lead exposure in dogs fed game meat and offal and, to our knowledge, the first study exploring associations between game consumption and dog health status. We quantified lead concentrations in blood and hair and haematological parameters of 31 dogs fed game meat and offal from wild boar (Sus scrofa) and axis deer (Axis axis) culled with lead ammunition in El Palmar National Park, Argentina. Despite variable weekly frequency in game consumption, dogs had detectable blood and hair lead levels, demonstrating recent and chronic exposure. Lead geometric mean and SD were 18.91 ± 346.85 μg/dL w.w. in blood (range = 0.53-216.58), and 0.721 ± 6.444 μg/gr d.w. in hair (range = 0.007-34.800). Hair lead levels were relatively low in most samples, except for the oldest dog which had an atypically high value concurrent with anaemia, a common outcome of chronic lead exposure. Dog's owner was significantly predictive of both blood and hair lead levels, which reflects the same feeding patterns for all dogs owned by the same person. Body condition was associated with hair lead, with dogs in good condition presenting higher lead levels. This could be related to greater game consumption by those dogs, resulting in higher lead ingestion. Dogs fed game meat and offal at very low or low frequency (≤4 times per week) showed higher blood lead levels, suggesting there might not be a risk-free frequency for game provision to dogs. Considering the risks of dietary lead exposure, avoiding feeding dogs lead-killed game and replacing lead ammunition with non-toxic alternatives are recommended. This would allow using hunted game as a valuable food resource without unnecessary risk for the health of consumers and the environment.

Environmental chronic exposure to metals and effects on attention and executive function in the general population

Heavy metals are neurotoxic, associated with brain dysfunction, and have been linked with cognitive decline in adults. This study was aimed to characterize chronic exposure to metals (Cd, Be, Co, Hg, Sn, V, Al, Ba, Cr, Cu, Fe, Li, Mn, Ni, Pb, and Zn) and metalloids (As, B, Sb) and assess its impact on cognitive performance of Tehran's residents, capital of Iran. Scalp hair samples gathered from 200 volunteered participants (110 men and 90 women), aged 14-70 years and quantified by inductively coupled plasma atomic emission spectroscopy (ICP-OES). Attention and executive function, two measures of cognitive performance, were characterized using the trail making test (TMT) part A and B, respectively. Mental flexibility was characterized as the Delta TMT B-A scores and cognitive efficiency or dissimulation as the ration between TMT B and A scores. A comprehensive questionnaire was used to gather information on demographic and socioeconomic as well as lifestyle and health status. The highest and lowest mean concentrations were observed for B (325 μg/g) and As (0.29 μg/g), respectively. Results indicated that chronic metal exposure measured in hair changed significantly based on gender and age (p < 0.05). The levels of Cr, Fe, Ni, Si, Hg, Pb and B were significantly higher in males' hair, whereas those of Ag and Ba were greater in females' hair (p < 0.05). The results of the cognitive TMT test were significantly different between gender and age groups (p < 0.05). Moreover, results revealed that As, Hg, Mn, and Pb levels in hair were significantly associated with poorer participants' performance scores in the TMT test (p < 0.05). Age, gender, cigarette smoking, water-pipe smoking, traffic density in the area of residence, and dental amalgam filling were significant factors affecting the TMT test scores. The results suggest that chronic exposure to metals has detrimental effects on attention, executive function, mental flexibility and cognitive efficiency.

Trace Element Levels in the Elders over 80 from the Hainan Province of China

Trace elements are key regulators of metabolism and physiological pathways, and their levels change during aging. Hair, as a biological sample, has attracted much attention due to its ease of collection and slow substance metabolism. Also, trace elements in hair can reveal the distribution of essential nutrients and toxic elements in the body pools. Therefore, we investigated the lifestyle and dietary status by questionnaire and measured 8 trace elements in hair and 6 elements in blood of a sample of elders over 80 residing in Hainan province of China. Our data showed that the concentration of Se, Fe and Pb dropped as people grow older, but Mn rose. Changes in trace elements may affect enzyme activity and biological pathways, and are associated with many diseases, including cancer and chronic diseases. In addition, association between age-related diseases and trace elements are increasingly being reported, suggesting that approaches of combining nutrition with longevity studies in the further study will help us to identify the mechanisms whereby trace elements affect the aging process.

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.

High concentrations of lead and barium in hair of the rural population caused by water pollution in the Thar Jath oilfields in South Sudan

In the oil fields of Thar Jath, South Sudan, increasing salinity of drinking water was observed together with human incompatibilities and rise in livestock mortalities. Hair analysis was used to characterize the toxic exposure of the population. Hair samples of volunteers from four communities with different distance from the center of the oil field (Koch 23km, n=24; Leer 50km, n=26; Nyal 110km, n=21; and Rumbek 220km, n=25) were analyzed for altogether 39 elements by inductively coupled plasma-mass spectrometry. Very high concentrations and a toxic health endangerment were assessed for lead and barium. The concentration of lead increased steadily with decreasing distance from the oil field from Rumbek (mean 2.8μg/g) to Koch (mean 18.7μg/g) and was there in the same range as in highly contaminated mining regions in Kosovo, China or Bolivia. The weighting materials in drilling muds barite (BaSO₄) and galena (PbS) were considered to be the sources of drinking water pollution and high hair values. The high concentrations of lead and barium in hair demonstrate clearly the health risk caused by harmful deposition of toxic industrial waste but cannot be used for diagnosis of a chronic intoxication of the individuals.

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 203 μg/g in urban areas and 0.84, 13.4, 5.56, 14.5 and 169 μg/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.

Environmental lead exposure and its relationship to traffic density among Senegalese children: a cross-sectional study

Leaded-gasoline is probably the primary source of lead (Pb) exposure in Dakar (Senegal). The present cross sectional study was undertaken to investigate the levels of Pb in Senegalese children and to present helpful data on the relationship between Pb levels and changes in biological markers of heme biosynthesis and oxidative stress. A total of 330 children, living since birth either in rural or urban areas (ie, Khombole (n=162) and Dakar (n=168), respectively) were included. During this cross sectional study, the mean blood (B)-Pb level in all children was 7.32±5.33 ųg/dL, and was influenced by the area of residence and gender. In rural children, 27 subjects (16.7%), 18 boys (19.6%) and nine girls (12.9%), had a B-Pb level >10 ųg Pb/dL, whereas 99 urban children (58.9%), respectively, 66 boys (71.8%) and 33 girls (43.4%), had alarmingly high B-Pb levels. Accordingly, urine delta-aminolevulinic acid levels were higher in children living in the urban area than in the rural areas (P B±0.001), and closely correlated with the B-Pb levels (P B±0.01). Moreover, glutathione peroxidase (GPx) activity, selenium (Se) level, glutathione reductase (GR) activity, and glutathione status were significantly influenced by area of residence and/or by gender. GPx activity and Se level were not only negatively correlated with B-Pb levels, but also positively correlated together (P B±0.01). Taken together, the present results allow us to conclude that urban children have higher B-Pb levels than rural children, and that of these children, boys have higher B-Pb levels than girls, leading thereby to alterations of heme biosynthesis and pro-oxidant/antioxidant balance. We also suggest that exposure to Pb and the Pb-induced adverse effects merits attention and that the development of preventive actions are of increasing importance in Senegal.

Human exposure to toxic metals via contaminated dust: Bio-accumulation trends and their potential risk estimation

We assessed the levels of potentially toxic trace metals, Zinc (Zn), Lead (Pb), Manganese (Mn), Copper (Cu), Nickel (Ni), Chromium (Cr), Cobalt (Co), and Cadmium (Cd), in dust, hair, nail and serum, sampled in rural, urban and industrial areas of Punjab, Pakistan. Trace metals occurrence in all samples, in descending order, was: Zn, Pb, Mn, Cu, Cr, Ni, Co, Cd. The samples from the urban areas showed significantly higher concentration of toxic trace metals (Zn, Ni, Cr, Co, Mn, and Cd) than those from industrial (which conversely had higher levels of Pb and Cu), and than samples from rural areas. Bioaccumulation patterns showed that dust exposure is one of the major routes into human body for Cd, Pb, Co, Mn and Cr, while the burden of Zn, Cu, and Ni can be more linked to dietary sources. The concentrations of trace metals in the samples from Punjab were comparable and/or higher than those reported worldwide. In many cases, the levels of Zn, Cr, Pb, Ni and Cd in hair and nail were beyond the ATSDR threshold guideline values that may cause some serious health effects. Hazard Index (HI) calculated for trace metal concentrations in the human population of Punjab points particularly to health risks from Cd (for children in urban and industrial areas) and from Pb (for all sub-groups).

Monitoring lead in hair of children and adolescents of Alcalá de Henares, Spain. A study by gender and residential areas

In recent years there has been an increased interest from the European Union (EU) in the development of large Human Bio-monitoring (HBM) studies across Europe, especially biomonitoring toxic metals. In Spain, most studies using hair as a biomarker have been conducted to determine occupational or industrial exposures, and have involved adult populations. Few studies have involved adolescents and children, despite these groups being sensitive to environmental contamination and pollutants. Therefore, the objective of the present study was to determine the degree of lead exposure in children and adolescents residing in Alcalá de Henares, Spain. Lead poisoning is the number one toxicological threat in the environment. So, lead (Pb) was selected as it is a persistent environmental contaminant, is measureable and is also a neurotoxin that can affect brain development. The city of Alcalá de Henares was divided into four zones to determine the influence of residence area on Pb levels. A range of other variables including age and gender were also considered within the study. The study comprised 115 children (6-9 years old) and 96 adolescents (13-16 years old). There was a significant difference between the levels of Pb in the hair of adolescents, for different gender and area of residence (p<0.001 and p<0.01 respectively). There was no significant difference in the Pb levels in hair of children, for different gender or area of the city. The levels of Pb were significantly (p<0.001) elevated in children compared to adolescents (1.48 vs. 0.70 μg/g), and there was a significant difference in Pb levels in male and female adolescent hair (0.53 vs. 0.77 μg/g) (p<0.001). The association observed between areas of residence and the Pb level in hair of the adolescent group could be mainly attributed to dietary habits and/or socioeconomic status.

Metals and metalloids in hair samples of children living near the abandoned mine sites of Sulcis-Inglesiente (Sardinia, Italy)

The Sulcis-Iglesiente district (SW Sardinia, Italy) is one of the oldest and most important polymetallic mining areas in Italy. Large outcrops of sulfide and oxide ores, as well as the products of the long-lasting mining activity, are present throughout the district releasing significant quantities of metals and metalloids into the surrounding environment. Here are reported concentrations of 21 elements determined in scalp hair samples from children (aged 11-13 years) living in different geochemical environments of southwestern Sardinia: Iglesias, hosting several abandoned mines, and the island of Sant׳Antioco, not affected by significant base metal mineralization events. Trace element determinations were performed by ICP-MS. Statistically significant differences (p<0.01) in elemental concentration levels between the two study sites were found. Hair of children from Iglesias exhibited higher concentration values for Ag, Ba, Cd, Cr, Ni, Pb, Rb, Sb, U, V, and Zn. Rubidium, V and U resulted more abundant at Sant׳Antioco. Hair samples from Iglesias showed gender-related differences for a larger number of elements (Ag, Ba, Cd, Co, Cu, Ni, Sr, U and Zn) than at Sant׳Antioco, where only U was significantly different. The above elemental concentrations in females were always higher than in male donors. Robust Principal Component Analysis operated on log-transformed elemental concentrations showed components indicative of a) sulfides ore minerals (PC1) reflecting the influence of the diffuse mineralization covering the entire study area, b) the presence of some bioavailable As sources (PC2) as As-rich pyrite and Fe-containing sphalerite and c) other sources of metals overlapping the diffuse mineralizations, as carbonate rocks and coal deposits (PC3). The results provided evidence of a potential risk of adverse effects on the health of the exposed population, with children living at Iglesias being greatly exposed to several metals and metalloids originated in mining tailings, enriched soils, waters and food.

Investigation of saliva as an alternative matrix to blood for the biological monitoring of inorganic lead

INTRODUCTION

Whole blood is the established matrix for biological monitoring of inorganic lead; however blood sampling is an invasive procedure. Saliva offers a potential non-invasive alternative. This study determines lead in whole blood and saliva. A novel method for saliva sampling and preparation is presented.

METHODS

Paired blood and saliva samples were obtained from 105 occupationally exposed UK workers. Saliva was collected using a StatSure sampling device, and a nitric acid digestion step was incorporated. The utility of the device for this application was evaluated. Whole blood was obtained by venepuncture. Analyses were carried out by ICP-MS.

RESULTS

The limit of detection for lead in saliva was 0.011 μg/L. Mean blank-corrected recovery from 10 μg/L spiked saliva was 65.9%. The mean result from blank saliva extracted through the StatSure device was 2.86 μg/L, compared to 0.38 μg/L by direct analysis. For the paired samples, median blood lead was 6.00 μg/dL and median saliva lead was 17.1 μg/L. Pearson's correlation coefficient for saliva lead versus blood lead was 0.457 (95% C.I. 0.291-0.596).

CONCLUSIONS

ICP-MS analysis allows sensitive determination of lead in saliva with low limits of detection. The StatSure device is effective for high occupational exposures, but contamination from the device could confound lower-level measurements. Saliva would only be effective as a surrogate for whole blood for highly-exposed populations, although with further work it may have applications as a biomarker of recent exposure.

"Reference values" of trace elements in the hair of a sample group of Spanish children (aged 6-9 years) - are urban topsoils a source of contamination?

Human hair is used as a biomonitor to evaluate the environmental exposure to contaminants in the individual. However, the use of human hair is controversial, mainly because reference levels for pollutants in hair have not yet been set. In the case of Spain, few biomonitoring studies have involved infants and children. A biomonitoring study was conducted to investigate the possible normal values of trace elements of toxicological concern in children aged 6-9 years from the city of Alcalá de Henares, Community of Madrid (Spain), following the methodology and strict inclusion criteria previously developed by our group. Levels of Al, As, Be, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Ti, Tl, V and Zn were monitored in scalp-hair from 117 healthy children (47 boys and 70 girls) between April and May of 2001. The levels of trace elements here described could be considered as possible "reference values" for children aged 6-9 years resident in the Community of Madrid. These values might also be selected as a preliminary screening tool to evaluate if a Spanish child has been exposed to any of the contaminants studied here. This study also investigated whether local urban topsoils were a source of metals for this population.

Determination of exposure to lead of subjects from southwestern Poland by human hair analysis

The aim of the present work was to investigate the exposure to lead from various sources by investigation of mineral composition of human scalp hair. The research was carried out on hair sampled from 267 young adults living in Wrocław (southwest Poland). The effect of the place of residence, diet, and lifestyle on lead content in hair was examined by inductively coupled plasma optical emission spectrometry (ICP-OES). Lead was determined at the wavelength 220.353 nm. These outcomes were reached by linking the results of lead level in hair with the results of questionnaire survey. The mean lead level in hair of the whole examined population was 2.01 ± 2.10 mg kg(-1). Lead can enter the human body mainly by inhalation and gastrointestinal absorption. It was found that consuming cheese, fish, and lettuce caused increased level of lead in hair. On the other hand, drinking of milk, tea, coffee, or lemon resulted in decreased content of lead in hair. Additional source of exposure to lead could be cigarette smoking, distance to the traffic road, painting the walls, amalgam filling. Based on the results, it can be concluded that exposure to lead can occur mainly from eating habits and environmental exposure.

Lead, cadmium and zinc in hair samples: relationship with dietary habits and urban environment

This study was performed in order to analyze the relationships between hair zinc, lead, and cadmium with the kind of diet consumed (by recall of the diet consumed the previous 14 days), living area (urban or rural), tobacco smoking, and body mass index (BMI) among 419 individuals of the Canary Archipelago. Median values and interquartile range were 43 μg/g (18.50-132.50) for zinc, 4.09 μg/g (2.19-8.38) for lead, and 0.128 μg/g (0.05-0.30) for cadmium. We observed that hair zinc was markedly elevated among those consuming fish more frequently and, to a lesser amount, among those who consumed meat frequently, among those living in urban areas, and among those with BMI over 25 kg/m(2), keeping a significant relationship with BMI. Hair lead was also higher among fish consumers, showed a trend to higher values among inhabitants of urban areas, and was lower among obese individuals. Hair cadmium was higher among those who consumed less vegetables and fruits. By multivariate analysis, introducing the variables meat, fish, and vegetable consumption, urban/rural; sex; age; and BMI values, we observed that fish consumption (beta = 0.15) was the only variable independently associated to higher zinc levels; fish consumption (beta = 0.15) and meat consumption (beta = 0.17) were related to high cadmium levels, whereas meat consumption was significantly associated to higher hair lead levels (beta = 0.15). Therefore, we conclude that hair zinc, cadmium, and lead seem to depend more heavily on dietary habits than on tobacco consumption or living in rural or urban areas.

Exposure of lead to mothers and their new born infants, residents of industrial and domestic areas of Pakistan

Prenatal and early-life exposure to lead (Pb) is hypothesized to have adverse effects on childhood health. The aim of this study was to evaluate the prenatal exposure to Pb and its adverse effects on mothers and their infants who are residents of industrial (exposed) and domestic areas (referents) in Karachi, Pakistan. The biological samples (scalp hair and blood) of mother-infants pairs were analyzed for Pb levels by atomic absorption spectrometry after microwave-assisted acid digestion method. The Pb levels in scalp hair and blood samples of exposed mothers were found in the range of 7.52-8.70 μg/g and 115-270 μg/L, respectively, which were significantly higher than those values obtained for referent mothers (p < 0.001). The Pb levels in the blood (umbilical cord) and hair of neonates of exposed mother that were found in the range of 83-178 μg/L and 4.95-7.23 μg/g, respectively, were significantly higher than the obtained values of referent neonates (p > 0.001). The correlation between maternal and cord blood of both groups was found in the range of 0.708-0.724 (p < 0.01). It was observed that there were higher Pb burdens in exposed mothers and their infants as compared to referent mothers-neonates.

Adipose tissue: another target organ for lead accumulation? A study on Sardinian children (Italy)

OBJECTIVES

This study analyzes the relationship between lead levels and adipose tissue in Sardinian children. As an environmental pollutant, lead occurs in two different chemical forms: inorganic and organic lead; organic lead is present in the environment mainly as lead-alkyls (tetramethyl and tetraethyl lead). The lead-alkyls are characterized by their liposolubility; because of this characteristic, the behavior of organic Pb in the organism is similar to that of persistent organic pollutants (POPs). In fact, the high liposolubility of POPs, synthetic chemical substances highly resistant to biodegradation in both the environment and the human body, gives them a preferential tendency to accumulate in adipose tissue.

METHODS

The study sample consisted of 759 children between 11 and 15 years resident in various municipalities of Sardinia. Hair lead levels (PbH) were used as the biomarker of exposure, while several anthropometric indexes were adopted to evaluate the adipose tissue: weight, body mass index, waist circumference, waist to hip circumference ratio, and sum of skinfolds (Σskf).

RESULTS

The results of the multivariate ridge regression analysis, controlling for sex and age, show a significant positive relationship between logPbH and logΣskf but not the other adiposity indicators.

CONCLUSIONS

This results suggests that organic lead tends to accumulate in adipose tissue, although it would be appropriate to measure lead levels in the adipose tissue itself in order to verify the results. Hence this tissue could be considered a possible new biological matrix for the evaluation of environmental lead exposure.

Occupational and environmental lead exposure to adolescent workers in battery recycling workshops

Lead (Pb), as other environmental neurotoxicant substances, has the capability to interfere with many biochemical events present in cells throughout the body. In the present study, the environmental and occupational exposure to Pb has been assessed by analyzing the scalp hair samples of male adolescents aged 12-15 years, who have worked for the last 12-36 months in Pb battery recycling workshops (BRWs). For comparative purposes, gender and age-matched subjects living in the vicinity of recycling workshops as well as in areas without industrial activity were used as controls. The scalp hair samples were oxidized by acid in a microwave oven prior to determination of Pb by electrothermal atomic absorption spectrometry. The results indicated that both workers and nonworking exposed subjects had higher levels of Pb than nonexposed controls. The contents of Pb in scalp hair of adolescent workers in the present study were compared with those reported in other studies.

Salivary lead in relation to caries, salivary factors and cariogenic bacteria in children

BACKGROUND

Saliva has been suggested as a useful biomarker of environmental contamination, including exposure to lead.

AIMS

The study examined the associations between salivary lead level and the following factors: blood lead level, the number of decayed and filled surfaces (dfs) on deciduous and permanent teeth (DMFS), salivary flow rate, pH, buffer capacity, lactobacilli and mutans streptococci counts.

MATERIALS AND METHODS

One hundred and twenty saliva samples of children living in a shipyard area (known to be an area contaminated with lead) were analysed for lead. Clinical oral examination was conducted to define carious lesions in accordance with the criteria of the World Health Organisation.

RESULTS

The analysis revealed detectable levels of lead in a range of 0.16-28.52 μg/dl with a mean concentration of 2.26 ± 3.67 μg/dl. No significant differences in salivary lead concentrations were found in relation to gender and age. The salivary lead level significantly correlated with the blood lead level (Rs = 0.18, P = 0.05). There was no association between the salivary lead levels and dfs or DMFS. The results indicated that children with high salivary lead levels did not differ in flow rate, pH, buffer capacity of saliva from those with low lead levels. However, the number of mutans streptococci were reduced in the high salivary lead groups, while the lactobacilli count was not associated with the salivary lead levels.

CONCLUSIONS

The current finding suggests that saliva may not have potential to be an appropriate alternative for biological monitoring of lead exposure.

Determinants of lead exposure in children on the outskirts of Salvador, Brazil

Lead (Pb) is a toxic heavy metal that is widely distributed throughout the environment. Pb is an important neurotoxic metal and children are more susceptible to its effect due to their higher absorption rate and greater susceptibility of the developing nervous system. In this work, we evaluated the lead exposure levels in children living near a metallurgical plant and identified risk factors associated with its internal dose. All children, aged 1-10 years and 11 months, living near a metallurgical plant in the great Salvador area, Brazil were evaluated in this cross-sectional study and compared with children from a non exposed area. Occipital hair and blood were used to assess exposure. Air lead levels in the respirable fraction (PM(2.5)) were also measured in both areas. Blood lead levels (BLL), hair lead levels (PbH) and air lead were determined by graphite furnace atomic absorption spectrometry. Spearman correlations analysis was used to evaluate correlations between BLL, PbH and descriptors. Significant risk factors were modeled using multivariate linear regression analysis. Air lead levels were approximately ten-folds lower than EPA reference concentration (0.15 μg/m(3)). Median BLL and PbH were 1.65 ± 1.45 μg/dL and 1.26 ± 3.70 μg/g, respectively, in exposed children. In the referents, medians were BLL 1.20 ± 1.20 μg/dL; PbH 2.09 ± 2.06 μg/g. No significant difference was observed in biomarkers levels between boys and girls. It was observed a positive weak correlation (Spearman rho = 0.197, p = 0.033) between BLL and PbH. Our data show that children's lead body burden measured as BLL or PbH are low when compared with the recommended reference values. Despite that, we were able to identify four risk factors associated with increased biological lead levels: age, living near industrial site, environmental tobacco smoking and, above all, domestic waste burning. In order to prevent such avoidable exposure, environmental education and proper waste management should be implemented, especially in developing countries.

Concentration and reference interval of trace elements in human hair from students living in Palermo, Sicily (Italy)

Trace element contents in specimens of hair collected from 137 children aged 11-13 years old, living in Palermo (Sicily, Italy) were determined by ICP-MS. This work reports analytical data for the following 19 elements: Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, U, V and Zn. The most abundant chemical elements were zinc and copper (Zn > Cu), with concentrations exceeding 10 μg/g (Zn = 189.2 μg/g; Cu = 22.9 μg/g). Other elements with concentrations greater than 1 μg/g were, in order of abundance, Al>Sr>Ba>Pb. The remaining elements were all below 1 μg/g. The average elemental concentrations in hair were statistically compared by Kolmogorov-Smirnov's test taking children's gender into account. Al, Ba, Cr, Li, Rb, Sb, Sr, V and Zn were statistically different according to gender, with significance p < 0.001. This study thus confirms the need for hair analysis to differentiate female data from those of males. IUPAC coverage intervals and coverage uncertainties for trace elements in the analysed hair samples are also reported.

The influence of environmental exposure on lead concentrations in scalp hair of children in Pakistan

In the present study the environmental and occupational exposure of Pb has been assessed by analyzing the scalp hair (SH) of children (both genders), residing in the vicinity of industrial area of Hyderabad, Pakistan. A total of 339 children attending primary schools situated in the industrial area, age ranged 5-10 years, while for comparative purpose children of the same age group from schools located in an area devoid of industries, were selected. The scalp hair was oxidized by acid mixture in a microwave oven prior to determination of Pb by graphite furnace atomic absorption spectrometry. The concentration profile of Pb in SH of children showed that the level changed significantly (44-64%) with changes of living habits or environmental exposure. The influence of age, sex, and family occupation on the children's hair Pb concentration was also evaluated. Significant differences in SH-Pb levels were observed between the exposed (EXC) and non-exposed (NEC) children (p<0.01). The concentration of Pb in boys of exposed (EX) and non-exposed (NEX) area was more than in girls of the corresponding localities. The boys and girls of NEX and EX areas have SH-Pb in the range of 3.97-5.4 and 6.06-13.7 μg g(-1) and 3.41-7.4 and 5.56-11.5 μg g(-1), respectively. The Pb levels increased with age in both study groups.

Lead contents in the surface enamel of primary and permanent teeth, whole blood, serum, and saliva of 6- to 8-year-old children

This study aimed to evaluate associations of Pb-enamel values determined in two successive enamel microbiopsies taken from a primary and a permanent tooth, and to assess how Pb-enamel correlates with Pb-blood and Pb-serum as well as whole (Pb-whole-saliva), submandibular/sublingual (Pb-sub-saliva) and parotid saliva (Pb-parotid-saliva). The study population included 444 children aged 6 to 8years attending 4 government schools in the district of Campos Eliseos, in Ribeirao Preto, Sao Paulo State, Brazil. Whole blood, serum, parotid, submandibular/sublingual ("sub-saliva"), and whole saliva were collected in trace element-free tubes. Two successive microbiopsies were taken from the surface of a primary and a permanent tooth of each child. Lead concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS). There was a significant correlation between primary and permanent teeth in terms of Pb-enamel, for both the first and the second microbiopsies. When the median Pb-enamel values were compared between the two genders using only the highest 10th percentile Pb-enamel, there was a significant difference between girls and boys for both primary (474.2 vs 910.0μg/g, respectively; p=0.02) and permanent teeth (739.5 vs 1325μg/g, respectively; p=0.04). There were no significant correlations between Pb-enamel and Pb-blood or between Pb-enamel and lead in the 3 different salivas. However, there was a statistically significant correlation between Pb-enamel and Pb-serum when only the highest 10th percentile Pb-enamel was analyzed (r=0.57 and p=0.0002 for primary teeth; r=0.56 and p<0.0001, for permanent teeth). In conclusion, our findings have demonstrated a significant correlation between Pb-enamel found in primary and permanent teeth, as well as a significant correlation between Pb-serum and lead in primary and permanent tooth enamel. Boys presented higher Pb-enamel than girls. Our study also suggests that Pb-enamel has no correlation with Pb-blood or with lead in the 3 different salivas.

Hair analysis as a biomonitor for toxicology, disease and health status

Hair analysis receives a large amount of academic and commercial interest for wide-ranging applications. However, in many instances, especially for elemental or 'mineral' analysis, the degree of success of analytical interpretation has been quite minimal with respect to the extent of such endeavors. In this critical review we address the questions surrounding hair analysis with specific intent of discovering what hair concentrations can actually relate to in a biogenic sense. This is done from a chemistry perspective to explain why and how elements are incorporated into hair and their meaning. This includes an overview of variables attributed to altering hair concentrations, such as age, gender, melanin content, and other less reported factors. Hair elemental concentrations are reviewed with regard to morbidity, with specific examples of disease related effects summarized. The application of hair analysis for epidemiology and etiology studies is enforced. A section is dedicated specifically to the area of population studies with regards to mercury, which highlights how endogenous and exogenous incorporation relies on species dependant metabolism and metabolic products. Many of the considerations are relevant to other areas of interest in hair analysis, such as for drug and isotopic analysis. Inclusion of a table of elemental concentrations in hair should act as a valuable reference (298 references).

Trace element concentrations in hair of healthy Chinese centenarians

Trace element concentrations, as indicators of micronutrient status of healthy centenarians, have not been widely analyzed. This study aimed to assess trace element concentrations in the hair of healthy centenarians. The effects of gender and age on element concentrations were also investigated. Eleven trace elements (Al, Ba, Cd, Cr, Cu, Fe, Mo, Pb, Se, Sr and Zn) in the scalp hair of 107 healthy Chinese centenarians were examined. The overall reference values (RVs) in mg/kg for the hair concentrations of trace elements in centenarians were as follows: Al, 14.95; Ba, 2.68; Cd, 0.06; Cr, 0.59; Cu, 6.21); Fe, 19.37; Mo, 0.50; Pb, 4.64; Se, 0.37; Sr, 4.84; and Zn, 154.37. Data analysis found that only Cu and Zn concentrations show a normal distribution, and there is no significant difference between males and females in any element except Zn. However, the levels of Al, Cd, Cr, Fe, Mo, Pb decrease and the levels of Ba, Cu, Se, Sr, Zn increase with age in the centenarian cohort. Results also revealed that sufficient Zn and Se concentrations as well as low exposure to heavy metals pollution contribute to the longevity of centenarians. The results imply the possibility of manipulating trace element concentrations, especially Zn and Se concentrations in tissues, as a means for therapeutic modality in geriatric disease.

Quantitative analysis of toxic and essential elements in human hair. Clinical validity of results

Over the last three decades, there has been an increasing awareness of environmental and occupational exposures to toxic or potentially toxic trace elements. The evolution of biological monitoring includes knowledge of kinetics of toxic and/or essential elements and adverse health effects related to their exposure. The debate whether a hair is a valid sample for biomonitoring or not is still attracting the attention of analysts, health care professionals, and environmentalists. Although researchers have found many correlations of essential elements to diseases, metabolic disorders, environmental exposures, and nutritional status, opponents of the concept of hair analysis object that hair samples are unreliable due to the influence of external factors. This review discusses validity of hair as a sample for biomonitoring of essential and toxic elements, with emphasis on pre-analytical, analytical, and post-analytical factors influencing results.

Saliva as an analytical matrix: state of the art and application for biomonitoring

Analytical tests to measure chemicals in saliva can be employed for numerous analytes, endogenous compounds or xenobiotics. The objective was to determine which chemicals can be analysed with this matrix, which analytical methods are applicable, and what application is possible for biomonitoring. We reviewed the literature using three databases, MEDLINE, PubMed and Scopus, collecting articles on different kinds of analysis in saliva. Studies were principally about molecules of clinical interest, xenobiotics, especially drugs of abuse, and chemicals used at workplaces; some substances show no relevant correlation with exposure data while others seems to be of particular interest for systematic use for biomonitoring. Currently, saliva is used far less than other biological fluids but its use for biomonitoring of exposure to chemicals might open up new areas for research and would certainly simplify the collection of biological samples.

Whole blood, serum, and saliva lead concentrations in 6- to 8-year-old children

With increasing evidence of adverse health effects of lower lead levels (below 10microg/dL in whole blood), studies on novel internal dose biomarkers are needed. This study aimed at: (1) assessing the lead exposure by measuring this element in whole blood (Pb-blood), serum (Pb-serum), and 3 different types of saliva: whole (Pb-whole-saliva), submandibular/sublingual (Pb-sub-saliva) and parotid saliva (Pb-parotid-saliva); (2) correlating Pb-blood with Pb-serum; and (3) relating Pb-blood and Pb-serum with the lead found in the different salivas. The study population included 444 children aged 6 to 8 years attending 4 government schools in the district of Campos Eliseos, in Ribeirao Preto, Sao Paulo State, Brazil. Whole blood, serum, parotid, submandibular/sublingual ("sub-saliva"), and whole saliva were collected in trace element-free tubes. Lead concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Median Pb-blood and Pb-serum were 2.1microg/dL and 0.4microg/L, respectively. Ten percent of the children had Pb-blood between 4.0 and 9.4microg/dL. Boys showed higher Pb-blood than girls (2.3 vs. 2.0microg/dL, p<0.0003). Lead concentrations in whole, sub, and parotid saliva were 1.7, 1.4, and 1.3microg/L, respectively. No significant correlations were found between Pb-blood and Pb-serum, between Pb-blood and lead in the 3 different salivas, or between Pb-serum and Pb-whole-saliva or Pb-sub-saliva. However, there was a weak statistically significant correlation between Pb-serum and Pb-parotid-saliva. In conclusion, the mean Pb-blood concentration was 2.4microg/dL, with 10% of the children exhibiting Pb-blood between 4.0 and 9.4microg/dL. Boys presented higher Pb-blood. Results suggest that Pb-blood has no correlation with Pb-serum or lead in the 3 different salivas collected here. A weak but statistically significant correlation between Pb-serum and Pb-parotid-saliva was found. Our results also point to the need for carrying out more studies on sources of exposure and lead levels in children in Brazil.

Adverse health effects of lead exposure on children and exploration to internal lead indicator

Our research on adverse effects of lead exposures on physical and neurobehavioral health of children aged 6-12years in 4 villages, labeled as K, M, L, and X, in rural China, was reported in this article. Lead in blood (PbB), urine (PbU), hairs (PbH), and nails (PbN) were measured by graphite furnace atomic absorption spectrometry. Abbreviated Symptom Questionnaire of Conner's instruments and Revised Raven's Standard Progressive Matrices were applied to evaluate childhood attention deficit/hyperactivity disorders (ADHD) and intelligences. Geometric means (SD) of PbB, PbU, PbH and PbN concentrations were 71.2 microg/L (1.56), 11.7 microg/g (1.75), 12.5 microg/g (2.82), and 25.3 microg/g (2.79), respectively. 54 (17.0%) children had PbB levels of > or =100 microg/L. Boys, 6-10 years old, and living in village K were 2.11, 2.48, and 9.16 times, respectively, more likely to be poisoned by lead than girls, aged 11-12 years, and residing in X. 18 (5.7%) and 37 (11.7%) subjects had ADHD and mental retardations, respectively. Inverse relationships between intelligences and natural log transformed PbU and PbH levels were observed with respective odds ratios (95%CI) of 1.79 (1.00-3.22) and 1.46 (1.06-2.03) or 1.28 (1.04-1.58) and 1.73 (1.18-2.52) by binary or ordinal logistic regression modeling. ADHD prevalence was different by gender and age of subjects. PbU, PbH, and PbN related to PbB positively with respective correlation coefficients of 0.530, 0.477, and 0.181. Receiver operating characteristic (ROC) curves of the three measurements revealed areas under curves (AUCs) being 0.829, 0.758, and 0.687, respectively. In conclusion, children had moderate levels of lead exposures in this rural area. Intelligence declines were associated with internal lead levels among children. ROC analysis suggests PbU an internal lead indicator close to PbB.

Lead in saliva from lead-exposed and unexposed children

INTRODUCTION

Whole blood is used for diagnosis of lead exposure. A non-invasive method to obtain samples for the biomonitoring of lead contamination has become a necessity. This study 1) compares the lead content in whole saliva samples (Pb-saliva) of children from a city with no reported lead contamination (Ribeirão Preto, São Paulo State, Brazil) and children of a region notoriously contaminated with lead (Bauru, São Paulo State, Brazil), and 2) correlates Pb-saliva with the lead content in the enamel microbiopsy samples (Pb-enamel) in the case of these two populations.

METHODS

From a population of our previous study that had included 247 children (4- to 6-year-old) from Ribeirão Preto, and 26 children from Bauru, Pb-saliva was analyzed in 125 children from Ribeirão Preto and 19 children from Bauru by inductively coupled plasma mass spectrometry (ICPMS). To correlate Pb-saliva with Pb-enamel, we used Pb-enamel data obtained in our previous study. The Mann-Whitney test was employed to compare the Pb-saliva data of the two cities. Pb-saliva and Pb-enamel values were then Log10 transformed to normalize data, and Pb-saliva and Pb-enamel were correlated using Pearson's correlation coefficient.

RESULTS

Median Pb-saliva from the Ribeirão Preto population (1.64 microg/L) and the Bauru population (5.85 microg/L) were statistically different (p<0.0001). Pearson's correlation coefficient for Log10 Pb-saliva versus Log10 Pb-enamel was 0.15 (p=0.08) for Ribeirão Preto and 0.38 (p=0.11) for Bauru.

CONCLUSIONS

A clear relationship between Pb-saliva and environmental contamination by lead is shown. Further studies on Pb-saliva should be undertaken to elucidate the usefulness of saliva as a biomarker of lead exposure, particularly in children.

Non-invasive matrices in human biomonitoring: a review

Humans and other living organisms are exposed to a variety of chemical pollutants that are released into the environment as a consequence of anthropogenic activities. Environmental pollutants are incorporated into the organism by different routes and can then be stored and distributed in different tissues, which leads to an internal concentration that can induce different alterations, adverse effects and/or diseases. Control measures should be taken to avoid these effects and human biomonitoring is a very useful tool that can contribute to this aim. Human biomonitoring uses different matrices to measure the target chemicals depending on the chemical, the amount of matrix necessary for the analysis and the detection limit (LOD) of the analytical technique. Blood is the ideal matrix for most chemicals due to its contact with the whole organism and its equilibrium with organs and tissues where chemicals are stored. However, it has an important disadvantage of being an invasive matrix. The development of new methodology and modern analytical techniques has allowed the use of other matrices that are less or non-invasive, such as saliva, urine, meconium, nails, hair, and semen or breast milk. The presence of a chemical in these matrices reflects an exposure, but correlations between levels in non-invasive matrices and blood must be established to ensure that these levels are related to the total body burden. The development of new biomarkers that are measurable in these matrices will improve non-invasive biomonitoring. This paper reviews studies that measure Cd, Pb, Hg, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and phthalates in non-invasive matrices, the most used techniques for measurements and what alternative techniques are available.

The assessment of environmental and occupational exposure to hazardous substances by biomonitoring

BACKGROUND

Modern biomonitoring has expanded beyond its origins in occupational medicine to cover a wide variety of diagnostic procedures and assessments of environmental pollution, ranging from exposure to heavy metals and chemicals to the effects of pesticides and environmental tobacco smoke. In biomonitoring, the overall pollutant load and hazardous exposure of an organism is quantitatively determined, by monitoring the pollutants themselves, their metabolic products and/or conjugates with protein or DNA, in either serum, urine or other body fluids, as well as tissue samples in exceptional circumstances.

METHODS

A selective survey of the current literature is exemplified by our recent scientific and clinical experience.

RESULTS

Biomonitoring is an excellent way to monitor potentially hazardous substances, especially for the assessment of systemic uptake from chronic exposure and the evaluation of subsequent health risks. Investigative biomonitoring can highlight incidental/accidental intoxication in individuals and provide new categories of problematic pollutants relevant to the general population.

CONCLUSIONS

In combination with diagnostic procedures, biomonitoring provides an important contribution to the rational assessment of currently recorded pollutants and resulting health risks. It is as an evaluation tool available in daily practice as well as in health and environmental research applications. Legislation is already implemented that incorporates biomonitoring within the remit of specified occupational health screening.

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.

Town and gender effects on hair lead levels in children from three Sardinian towns (Italy) with different environmental backgrounds

This study reports hair lead (PbH) levels measured in 2002 in 193 children from three Sardinian towns: Carbonia, Gonnesa, and Sinnai. Carbonia and Gonnesa are in a polluted area of Sardinia due to their vicinity to the industrial zone of Portovesme. As a consequence of its economy and location, Sinnai is not exposed to lead pollution. PbH concentrations were determined by inductively coupled plasma atomic absorption spectrometry. The aim of this study was to evaluate if hair is a reliable biomarker to determine different degrees of exposure of populations to lead pollution and if there is a tendency to higher accumulation by males or females. The girls of Carbonia had the highest mean PbH value (2.21 microg/g), followed by the Gonnesa girls (2.03 microg/g), Carbonia boys (1.86 microg/g), Gonnesa boys (0.91 microg/g), and finally the Sinnai boys (0.68 microg/g) and girls (0.50 microg/g). Two-way analysis of covariance, with age as covariate, revealed a significant effect of town and sex on log PbH. Spearman's rank correlation coefficient indicated a significant positive concordance between PbH levels and gender (score for males=1, females=2). The results suggest that hair is a reliable biomarker to determine different levels of exposure of populations to lead pollution, and they indicate that females tend to accumulate lead in the hair more than males of the same age.

Hair-Pb longitudinal profiles and blood-Pb in the population of young Slovenian males

Hair-Pb longitudinal profiles of 25 mm hair length were measured in a population of Slovenian men (aged 18-25 years) using "tape sandwich" solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS). From these data two parameters related to Pb exposure were deduced. Hair-Pb proximal (H-Pbprox.) denotes the Pb content of the proximal 3mm hair segment, while Hair-Pb average (H-Pbaver.) denotes the average Pb content of a 25 mm hair length. The former were found to be on average at least a factor of 2 lower than the H-Pbaver. values that are normally reported in the literature for hairs of 20-50 mm length. Hair-Pb gradient (H-Pbgrad.) defined as the difference in Pb content between the distal (25 mm) and the proximal (3 mm) hair segments divided by the hair length was found to be highly correlated to the level of air Pb pollution (R=0.9931; P<0.001; n=5), while association between H-Pbprox. and air-Pb was not significant (R=0.5765; P>0.05; n=5). Simultaneously, lead in whole blood (B-Pb) was determined by ETAAS as another parameter of Pb exposure. The frequency distribution of log B-Pb values followed a symmetrical Gaussian shape with a median value of 35 microg Pb/L. Log H-Pbprox. frequency distribution, on the contrary, showed a Poissonian shape. Transformation of the data revealed the existence of four homogeneous groups of males with different median H-Pbprox. values (40, 86, 326 and 2500 ng/g). The major proportion of the Slovenian male population ( approximately 70%) has H-Pbprox. contents between 60 and 600 ng/g. A weak but statistically significant association was found between logs H-Pbprox. and B-Pb (R=0.3957; P<0.05; n=247) but when only those subjects were retained whose both parameters were determined with reasonable accuracy and were either above or below the predetermined value (B-Pb=50 microg/L; H-Pbprox.=450 ng/g), substantial improvement in the strength of correlation was observed (R=0.7049; P<0.01; n=84). The poor strength of association between these parameters was attributed to the large variation in Pb intake and different kinetics of Pb appearance in hair and blood. This statement is consistent with reports dealing with the relationship between H-Pb and B-Pb found in the literature.

Human biomonitoring studies in North Rhine-Westphalia, Germany

The areas along the rivers Rhine, Ruhr and Wupper in North Rhine-Westphalia (NRW), Germany, represent the largest urban and industrial agglomeration in Europe with about 10 million inhabitants. Human biomonitoring (HBM) studies have been conducted in these areas since more than 30 years, mainly designed to evaluate internal exposure to air pollutants. Recent studies were focussed on residents living near industrial sources. The contaminants studied comprise heavy metals, metabolites of polycyclic aromatic hydrocarbons (PAH), persistent organic pollutants (POPs), volatile organic compounds (VOC), and markers of DNA exposure. Study groups were mainly children and elderly subjects. Human milk, blood, urine, teeth, hair and nails were investigated. Time trend analyses demonstrate a significant decline of exposure to many contaminants such as POPs and heavy metals. More recent studies suggest that there still is an increased internal exposure to metals, PAH and DNA damaging agents in children and women living very close to industrial sources.

Human biomonitoring: State of the art

Human biomonitoring (HBM) of dose and biochemical effect nowadays has tremendous utility providing an efficient and cost effective means of measuring human exposure to chemical substances. HBM considers all routes of uptake and all sources which are relevant making it an ideal instrument for risk assessment and risk management. HBM can identify new chemical exposures, trends and changes in exposure, establish distribution of exposure among the general population, identify vulnerable groups and populations with higher exposures and identify environmental risks at specific contaminated sites with relatively low expenditure. The sensitivity of HBM methods moreover enables the elucidation of human metabolism and toxic mechanisms of the pollutants. So, HBM is a tool for scientists as well as for policy makers. Blood and urine are by far the most approved matrices. HBM can be done for most chemical substances which are in the focus of the worldwide discussion of environmental medicine. This especially applies for metals, PAH, phthalates, dioxins, pesticides, as well as for aromatic amines, perfluorinated chemicals, environmental tobacco smoke and volatile organic compounds. Protein adducts, especially Hb-adducts, as surrogates of DNA adducts measuring exposure as well as biochemical effect very specifically and sensitively are a still better means to estimate cancer risk than measuring genotoxic substances and their metabolites in human body fluids. Using very sophisticated but nevertheless routinely applicable analytical procedures Hb-adducts of alkylating agents, aromatic amines and nitro aromatic compounds are determined routinely today. To extend the spectrum of biochemical effect monitoring further methods should be elaborated which put up with cleavage and separation of the adducted protein molecules as a measure of sample preparation. This way all sites of adduction as well as further proteins, like serum albumin could be used for HBM. DNA-adducts indicate the mutagenicity of a chemical substance as well as an elevated cancer risk. DNA-adducts therefore would be ideal parameters for HBM. Though there are very sensitive techniques for DNA adduct monitoring like P32-postlabelling and immunological methods they lack specificity. For elucidating the mechanism of carcinogenesis and for a broad applicability and comparability in epidemiological studies analytical methods must be elaborated which are strictly specific for the chemical structure of the DNA-adduct. Current analytical possibilities however meet their borders. In HBM studies with exposure to genotoxic chemicals especially the measurement of DNA strand breaks in lymphocytes and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in white blood cells has become very popular. However, there is still a lack of well-established dose-response relations between occupational or environmental exposures and the induction of 8-OHdG or formation of strand breaks which limits the applicability of these markers. Most of the biomarkers used in population studies are covered by standard operating procedures (SOPs) as well as by internal and external quality assessment schemes. Therefore, HBM results from the leading laboratories worldwide are analytically reliable and comparable. Newly upcoming substances of environmental relevance like perfluorinated compounds can rapidly be assessed in body fluids because there are very powerful laboratories which are able to elaborate the analytical prerequisites in due time. On the other hand, it is getting more and more difficult for the laboratories to keep up with a progress in instrumental analyses. In spite of this it will pay to reach the ultimate summit of HBM because it is the only way to identify and quantify human exposure and risk, elucidate the mechanism of toxic effects and to ultimately decide if measures have to be taken to reduce exposure. Risk assessment and risk management without HBM lead to wrong risk estimates and cause inadequate measures. In some countries like in USA and in Germany, thousands of inhabitants are regularly investigated with respect to their internal exposure to a broad range of environmentally occurring substances. For the evaluation of HBM results the German HBM Commission elaborates reference- and HBM-values.

Baden-Wuerttemberg Environmental Health Survey (BW-EHS) from 1996 to 2003: toxic metals in blood and urine of children

The environmental health surveillance system in the Federal State of Baden-Wuerttemberg (South Germany), among others, was implemented to monitor pollutant exposures and their temporal and regional trends in children at the age of about 10 years. The investigations were performed in two larger cities, one small city and one rural area. Between 1996 and 2003, in total 5470 children were investigated in consideration of environmental health parameters in four cross-sectional studies. The data presented here cover the results of the determination of the internal load with toxic metals. The median values observed in the investigation in 2002/03 were: 4.6 microg/l urine for arsenic, less than 0.2 microg/l urine for mercury, 20.7 microg/l blood for lead, and 0.25 microg/l blood for cadmium. From 1996 to 2003, mercury concentrations showed a substantial decrease (-0.027 microg/l/year) and lead levels also decreased (-0.25 microg/l/year), whereas arsenic and cadmium levels did not change significantly over time. There was no consistent difference in the mean internal load of the metals between the four investigation areas. Important factors influencing the measured concentrations were consumption of fish in the last 48 h, which had an impact on arsenic (factor 2), and amalgam fillings, which accounted for an increase in mercury (factor 4.6). In the 2002/03 study period, levels above the limit of health concern for children (German HBM values) were found in about 0.5% of the lead measurements (maximum value 180 microg/l blood) and in about 0.2% of the mercury measurements (maximum value 8.2 microg/l urine). In conclusion, this environmental health survey generates objective data on secular trends and regional differences and provides insight into probable sources of toxic metal exposure in children.

Childhood lead exposure in the palestinian authority, Israel, and Jordan: results from the Middle Eastern regional cooperation project, 1996-2000

In the Middle East, the major sources of lead exposure have been leaded gasoline, lead-contaminated flour from traditional stone mills, focal exposures from small battery plants and smelters, and kohl (blue color) in cosmetics. In 1998-2000, we measured blood lead (PbB) levels in children 2-6 years of age in Israel, Jordan, and the Palestinian Authority (n = 1478), using a fingerstick method. Mean (peak; percentage > 10 microg/dL) PbB levels in Israel (n = 317) , the West Bank (n = 344), Jordan (n = 382) , and Gaza (n = 435) were 3.2 microg/dL (18.2 ; 2.2%) , 4.2 microg/dL (25.7; 5.2%), 3.2 microg/dL (39.3; < 1%) , and 8.6 microg/dL (> 80.0; 17.2%), respectively. High levels in Gaza were all among children living near a battery factory. The findings, taken together with data on time trends in lead emissions and in PbB in children in previous years, indicate the benefits from phasing out of leaded gasoline but state the case for further reductions and investigation of hot spots. The project demonstrated the benefits of regional cooperation in planning and carrying out a jointly designed project.

Evaluation of the use of salivary lead levels as a surrogate of blood lead or plasma lead levels in lead exposed subjects

We conducted a study to evaluate the use of parotid salivary lead (Pb-saliva) levels as a surrogate of the blood lead (Pb-B) or plasma lead levels (Pb-P) to diagnose lead exposure. The relationship between these biomarkers was assessed in a lead exposed population. Pb-saliva and Pb-P were determined by inductively coupled plasma mass spectrometry, while in whole blood lead was determined by graphite furnace atomic absorption spectrometry. We studied 88 adults (31 men and 57 women) from 18 to 60 years old. Pb-saliva levels varied from 0.05 to 4.4 microg/l, with a mean of 0.85 microg/l. Blood lead levels varied from 32.0 to 428.0 microg/l in men (mean 112.3 microg/l) and from 25.0 to 263.0 microg/l (mean 63.5 microg/l) in women. Corresponding Pb-Ps were 0.02-2.50 microg/l (mean 0.77 microg/l) and 0.03-1.6 microg/l (mean 0.42 microg/l) in men and women, respectively. A weak correlation was found between Log Pb-saliva and Log Pb-B (r=0.277, P<0.008), and between Log Pb-saliva and Log Pb-P (r=0.280, P=0.006). The Pb-saliva/Pb-P ratio ranged from 0.20 to 18.0. Age or gender does not affect Pb-saliva levels or Pb-saliva/Pb-P ratio. Taken together, these results suggest that salivary lead may not be used as a biomarker to diagnose lead exposure nor as a surrogate of plasma lead levels at least for low to moderately lead exposed population.