Biological Fluids as a Source of Information on the Exposure of Man to Environmental Chemical Agents

Methylenediphenyl diisocyanate lysine conjugates in the urine of workers exposed to methylenediphenyl diisocyanate

Diisocyanates have long been a leading cause of occupational asthma. As control often relies on personal protective equipment and there is the potential for skin uptake, biological monitoring is often used to assess worker exposure. Current routine biological monitoring methods do not distinguish between a diisocyanate and the corresponding diamine exposure in urine samples; therefore, a specific urinary biomarker is desirable. Urine samples were obtained from a group of workers exposed to methylenediphenyl diisocyanate (MDI) where aerosol generation was unlikely. Lysine conjugates of MDI were extracted from urine by solid phase extraction; analysis was performed by liquid chromatography tandem mass spectrometry. Acetylated MDI-lysine (acMDI-Lys) conjugates were detected in 73% of samples tested from persons with exposure to MDI compared to 93% of samples that were positive for methylene dianiline (MDA) in hydrolysed urine. There was a weak but significant positive correlation between the two biomarkers (r² = 0.377). This is the first report detecting and quantifying acMDI-Lys in the urine of workers exposed to MDI, and acMDI-Lys may be a useful non-invasive biomarker in discriminating between MDI and MDA exposures.

Urinary Mercury Levels and Predictors of Exposure among a Group of Italian Children

Urinary mercury (Hg) levels are suitable to assess long-term exposure to both elemental and inorganic Hg. In this study, the urinary Hg levels of 250 children (aged 6–11 years) from three areas with different anthropogenic impacts in the Rieti province, central Italy, were assessed. The Hg concentrations were in the range of 0.04–2.18 µg L⁻¹ with a geometric mean equal to 0.18 µg L⁻¹ [95% confidence interval (CI), 0.17–0.20 µg L⁻¹] or 0.21 µg g⁻¹ creatinine (95% CI, 0.19–0.23 µg g⁻¹ creatinine), and a reference value calculated as 95th percentile of 0.53 µg L⁻¹ (95% CI, 0.44–0.73 µg L⁻¹) or 0.55 µg g⁻¹ creatinine (95% CI, 0.50–0.83 µg g⁻¹ creatinine). In all cases, urinary Hg data were below the HBM-I values (7 µg L⁻¹ or 5 µg g⁻¹ creatinine) established for urine, while the 95th percentile was above the German Human Biomonitoring Commission’s RV95 (0.4 µg L⁻¹) set for children without amalgam fillings. A significant correlation (p < 0.05) was found between creatinine-corrected results and residence area, with higher urinary Hg levels in children living in the industrial area. Multiple linear regression analysis showed that creatinine was the main predictor of urinary Hg.

Evaluate the effect of cadmium on levels of zinc in scalp hair and blood samples of smoker and nonsmoker psoriatic patients at different stage

Psoriasis, a skin inflammatory disease, originates from dysregulated interactions of the immune system and environmental factors. In the present study, cadmium (Cd) and zinc (Zn) were analyzed in biological samples (blood and scalp hair) of smoker and nonsmoker males who have mild and severe psoriasis. The patients were evaluated according to criteria based on the standard clinical diagnosis and classified into mild and severe psoriasis groups using the Psoriasis Area Severity Index (PASI) score. Both elements were determined by atomic absorption spectrometry after matrix oxidation. In smoker psoriatic patients, the level of Cd in biological samples was significantly increased. The Zn was significantly decreased in smoker mild and severe psoriatic patients as related to nonsmokers' referents and patients. The resulted data indicated that the levels of Zn in smoker referents were about 5.0% lower than nonsmoker's referents. While the concentrations of Zn in blood samples of nonsmoker's mild and severe psoriatic patients have 17.8 to 33.3% lower than nonsmoker's referents. The results indicate that the level of Cd in blood samples of referent smokers has ≥ 25% than nonsmokers, whereas the psoriatic patients at different stages have two- to threefold higher Cd in both biological samples.

Interaction of Lead with Calcium, Iron, and Zinc in the Biological Samples of Malnourished Children

Interaction between toxic and essential elements is of particular interest, because the deficiency of essential element can dramatically increase the absorption rate of toxic metals inside the body. This study was conducted to evaluate the possible correlation of lead (Pb) with calcium (Ca), iron (Fe), and zinc (Zn) in biological samples (whole blood and scalp hair) of malnourished children (MNC). For comparative purposes, age-matched, well-nourished children (WNC) were selected. The concentrations of understudy elements were analyzed by atomic absorption spectrophotometry after microwave acid digestion. The accuracy of the methodology, as well as its its validity and efficiency, was checked through certified reference material of whole blood and scalp hair. The result indicates that the MNC have a twofold higher level of Pb, while the levels of essential elements (Ca, Fe, and Zn) were onefold to twofold lower as compared to the WNC (p < 0.05). Significant negative correlations of Pb with Ca, Fe, and Zn were found in the studied malnourished population at p < 0.05. Further research studies are required to elucidate the role of these metals and the mechanism of interaction inside the body.

Recent views of heavy metals as possible risk factors and potential preventive and therapeutic agents in prostate cancer

Prostate cancer is the most common cancer in men in many industrialized countries. A role for androgens in prostate tumor progression is well recognized, while estrogens may cooperate with androgens in prostate carcinogenesis. The incidence of prostate cancer is highly variable in the different countries, suggesting an important role of environmental factors. Heavy metals are common environmental contaminants and some of them are confirmed or suspected human carcinogens. Some metals are endowed with estrogenic and/or androgenic activities and may play a role as cancer risk factors through this mechanism. Moreover, prostate cancer may present alterations in the intracellular balance of trace metals, such as zinc and copper, which are involved in several regulatory proteins. Herein, we review the possible role of environmental heavy metals and of metal-dyshomeostasis in prostate cancer development and promotion as well as the potential use of some metals in the prevention and therapy of prostate cancer.

Blood-borne biomarkers and bioindicators for linking exposure to health effects in environmental health science

Environmental health science aims to link environmental pollution sources to adverse health outcomes to develop effective exposure intervention strategies that reduce long-term disease risks. Over the past few decades, the public health community recognized that health risk is driven by interaction between the human genome and external environment. Now that the human genetic code has been sequenced, establishing this "G × E" (gene-environment) interaction requires a similar effort to decode the human exposome, which is the accumulation of an individual's environmental exposures and metabolic responses throughout the person's lifetime. The exposome is composed of endogenous and exogenous chemicals, many of which are measurable as biomarkers in blood, breath, and urine. Exposure to pollutants is assessed by analyzing biofluids for the pollutant itself or its metabolic products. New methods are being developed to use a subset of biomarkers, termed bioindicators, to demonstrate biological changes indicative of future adverse health effects. Typically, environmental biomarkers are assessed using noninvasive (excreted) media, such as breath and urine. Blood is often avoided for biomonitoring due to practical reasons such as medical personnel, infectious waste, or clinical setting, despite the fact that blood represents the central compartment that interacts with every living cell and is the most relevant biofluid for certain applications and analyses. The aims of this study were to (1) review the current use of blood samples in environmental health research, (2) briefly contrast blood with other biological media, and (3) propose additional applications for blood analysis in human exposure research.

Assessment of selenium and mercury in biological samples of normal and night blindness children of age groups (3-7) and (8-12) years

The causes of night blindness in children are multifactorial and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence biological sample composition. This study was designed to compare the levels of selenium (Se) and mercury (Hg) in scalp hair, blood, and urine of night blindness children age ranged (3-7) and (8-12) years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment for the determination of Se and Hg in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The Se and Hg in biological samples were measured by electrothermal atomic absorption spectrometry and cold vapor atomic absorption spectrometry, prior to microwave acid digestion, respectively. The concentration of Se was decreased in scalp hair and blood samples of male and female night blindness children while Hg was higher in all biological samples as compared to referent subjects. The Se concentration was inversely associated with the risk of night blindness in both genders. These results add to an increasing body of evidence that Se is a protecting element for night blindness. These data present guidance to clinicians and other professional investigating deficiency of essential micronutrients in biological samples (scalp hair and blood) of night blindness children.

Comparative study of trace elements in blood, scalp hair and nails of prostate cancer patients in relation to healthy donors

Prostate cancer is the most common fatal cancers in men, and exposure to toxic elements is the most important factor in the aetiology for prostate cancer. Selected elements (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were analyzed in the blood, scalp hair and nails of prostate cancer patients and counterpart healthy donors by atomic absorption spectrometry. Average concentrations of Cd, Mn, Ni and Pb were found to be significantly higher (p < 0.05) in the blood, scalp hair and nails of the patients compared with those of the healthy subjects who exhibited significantly higher concentrations of Zn. The correlation study revealed significantly diverse relationships of the elements in the blood, scalp hair and nails of the two donor groups. Variations in the elemental concentrations were also noted for various types of prostate cancer (adenocarcinoma, squamous cell carcinoma, transitional cell carcinoma and small cell carcinoma), as well as for different stages of the cancer. Multivariate apportionment of trace elements in the blood, scalp hair and nails of the patients was also significantly different than that in the healthy donors. The study evidenced considerably divergent variations in the elemental concentrations in prostate cancer patients in comparison with healthy subjects.

Speciation of arsenic in saliva samples from a population of West Bengal, India

Saliva, an easily accessible biofluid, is validated as biomarker of arsenic (As) exposure in several villages of West Bengal, India. Pentavalent arsenic [As(V)] was found to be the predominant species in saliva, with the amount of inorganic As [As(V) and trivalent form, As(III)] being more than half of the total As in the samples. Significant association was found between total daily ingestion of As and As(V) (r = 0.59; p = 0.000), As(III) (r = 0.60; p = 0.000), dimethylarsinous acid (DMA(V)) (r = 0.40; p = 0.000), and monomethylarsonous acid (MMA(V)) (r = 0.44; p = 0.000), implying that these species have mainly been derived from the methylation of the inorganic As in the water that study participants drank and the food they ate. Analysis of confounding effects of age, sex, smoking, body mass index and the prevalence of skin lesion suggests that women and controls with no skin lesion had a higher capacity to methylate the ingested As compared to the rest of the population. Thus, our study demonstrates that As species in saliva can be an useful tool to predict the individual susceptibility where higher As exposure and a lower methylation capacity are implicated in the development of As-induced health effects.

Interaction between selenium and mercury in biological samples of Pakistani myocardial infarction patients at different stages as related to controls

It has been speculated that trace elements may a play role in the pathogenesis of heart diseases. In the present study, we aimed to assess the levels of selenium (Se) and mercury (Hg) in biological samples (whole blood, urine, and scalp hair) of myocardial infarction (MI) patients of both genders (age range 45-60 years) at the first, second, and third heart attack (n = 130), hospitalized in a cardiac ward of a civil hospital of Hyderabad City (Pakistan). For comparison, healthy age-matched referent subjects (n = 61) of both genders were also selected. Se and Hg in biological samples were measured by electrothermal atomic absorption spectrometry and cold vapor atomic absorption spectrometry, prior to microwave acid digestion, respectively. The validity of the methodology was checked by biological certified reference materials. During this study, 78 % of the 32 registered patients of third MI attack (aged >50 years) died. The concentration of Se was decreased in scalp hair and blood samples of MI patients, while Hg was higher in all biological samples as compared to referent subjects. Se concentration was inversely associated with the risk of MI attacks in both genders. These results add to an increasing body of evidence that Se is a protective element for cardiovascular health.

Chromium and manganese levels in biological samples of normal and night blindness children of age groups (3-7) and (8-12) years

This study was designed to compare the levels of chromium (Cr) and manganese (Mn) in scalp hair, blood, and urine of night blindness in children age ranged (3-7) and (8-12) years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure, was developed as a sample pretreatment, for the determination of Cr and Mn in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood and urine. The digests of all biological samples were analyzed for Cr and Mn by electrothermal atomic absorption spectrometry. The results indicated significantly higher levels of Cr, whilst low level of Mn in the biological samples (blood and scalp hair) of male and female night blindness children, compared with control subjects of both genders. These data present guidance to clinicians and other professional investigating deficiency of Mn and excessive level of Cr in biological samples (scalp hair and blood) of night blindness children.

Evaluation of essential trace and toxic elements in biological samples of normal and night blindness children of age groups 3-7 and 8-12 years

The most common cause of blindness in developing countries is vitamin A deficiency. The World Health Organization estimates 13.8 million children to have some degree of visual loss related to vitamin A deficiency. The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence biological samples composition. Vitamin and mineral deficiency prevents more than two billion people from achieving their full intellectual and physical potential. This study was designed to compare the levels of Zn, Mg, Ca, K, Na, As, Cd, and Pb in scalp hair, blood, and urine of night blindness children age ranged 3-7 and 8-12 years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment, for the determination of As, Ca, Cd, K, Pb, Mg, Na, and Zn in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The concentrations of trace and toxic elements were measured by atomic absorption spectrophotometer prior to microwave-assisted acid digestion. The results of this study showed that the mean values of As, Cd, Na, and Pb were significantly higher in scalp hair, blood, and urine samples of male and female night blindness children than in referents (p < 0.001), whereas the concentrations of Zn, Ca, K, and Mg were lower in the scalp hair and blood but higher in the urine samples of night blindness children. These data present guidance to clinicians and other professional investigating deficiency of essential mineral elements in biological samples (scalp hair and blood) of night blindness children.

Chromium and manganese levels in biological samples of Pakistani myocardial infarction patients at different stages as related to controls

It has been speculated that trace elements may play a role in the pathogenesis of heart diseases In the present study, we aimed to access the levels of chromium (Cr) and manganese (Mn) in biological samples (whole blood, urine, and scalp hair) of myocardial infarction (MI) patients of both gender age ranged (45-60 years) at first, second, and third heart attack (n = 130), hospitalized in cardiac ward of National Hospital of Hyderabad city (Pakistan). For comparison, healthy age-matched referent subjects (n = 61), of both gender were also selected. The Cr and Mn in biological samples were measured by electrothermal atomic absorption spectrometry, prior to microwave-assisted acid digestion. The validity of the methodology was checked by the biological certified reference materials. During this study, 78% of 32 registered patients of third MI attack (aged >50 years) were died. In these subjects the concentration of Cr and Mn were decreased by 24.7% and 19.8% in scalp hair, while in blood samples 17.9% and 12.4%, respectively, as compared to those who tolerated third MI attack (p = 0.063). Although these data do not prove a causal relationship, these results are consistent with the hypothesis that heart disease may cause deficiencies of certain essential trace elements. The excretion levels of Cr and Mn in urine samples of first MCI were higher than controls at p values (0.029 and 0.011), respectively, whereas the excretion rates of both elements were further enhance after second myocardial infarction attack. The Cr and Mn concentration was inversely associated with the risk of myocardial infarction attacks in both genders. These results add to an increasing body of evidence that, Cr and Mn are importance for cardiovascular health.

Evaluation of status of zinc, copper, and iron levels in biological samples of normal children and children with night blindness with age groups of 3-7 and 8-12 years

The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence hair composition. This study was designed to compare the levels of zinc (Zn), copper (Cu), and iron (Fe) in scalp hair, blood, and urine of both genders of children with night blindness with age range of 3-7 and 8-12 years, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment, for the determination of zinc, copper, and iron in biological samples of children with night blindness. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The digests of all biological samples were analyzed for Cu, Fe, and Zn by flame atomic absorption spectrometry using an air/acetylene flame. The results indicated significantly lower levels of Fe, Cu, and Zn in the biological samples (blood and scalp hair) of male and female children with night blindness, compared with control subjects of both genders. These data present guidance to clinicians and other professionals investigating the deficiency of essential trace metals in biological samples (scalp hair and blood) of children with night blindness.

Evaluation of status of cadmium, lead, and nickel levels in biological samples of normal and night blindness children of age groups 3-7 and 8-12 years

The causes of night blindness in children are multifactorial, and particular consideration has been given to childhood trace metals toxicity, which is the most common problem found in underdeveloped countries. This study was designed to compare the levels of cadmium (Cd), lead (Pb), and nickel (Ni) in scalp hair, blood, and urine of night blindness children age ranged 3-7 and 8-12 years of both genders, comparing them to sex- and age-matched controls. A microwave-assisted wet acid digestion procedure was developed as a sample pretreatment, for the determination of Cd, Pb, and Ni in biological samples of night blindness children. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, blood, and urine. The digests of all biological samples were analyzed for Cd, Pb, and Ni by electrothermal atomic absorption spectrometry. The results indicated significantly higher levels of Cd, Pb, and Ni in the biological samples (blood, scalp hair, and urine) of male and female night blindness children, compared with control subjects of both genders. These data present guidance to clinicians and other professional investigating toxicity of trace metals in biological samples of night blindness children.

Monitoring of occupational exposure to volatile organohalogen solvents (VOXs) in human urine samples of dry-cleaner workers by TLHS-DAI-GC-ECD procedure

Chlorinated hydrocarbon solvents are often used for dry-cleaning clothes in the laundry industry. The object of this study was to monitor the occupational exposure of dry-clean employees coming into contact with VOXs. Twenty five workers collected their urine samples before the work shift, after 4 h of work and after the work shift. The analyses of urine samples and solvents used in dry-cleaning were performed using TLHS-DAI-GC-ECD. Chloroform was detected in all urine samples, and dichloromethane and tetrachloroethene in nearly all urine samples collected before and after the work shift. The concentrations of the compounds determined in urine samples were higher at the end of the workday in directly exposed individuals. Concentrations of the compounds determined in urine samples depended mainly on the type of activities carried out at the dry-cleaning establishments.

Interaction of copper with iron, iodine, and thyroid hormone status in goitrous patients

In many developing countries, men and women are at high risk of goiter and iron deficiency. The aim of the recent study is to assess the interaction of (Cu), with iron (Fe), iodine/iodide (I), and thyroid hormones in goitrous patients. Sixty goitrous male (GMPs) and 72 female patients (GFPs) were evaluated for the Cu, Fe, I, and thyroid hormones status in biological samples (serum and urine), and compared to non-goitrous subjects of both genders (M = 106, F = 120). The biological samples were analyzed for Cu and Fe concentration using atomic absorption spectrometer, while I was measured by the potentiometric method, prior to microwave-assisted acid digestion (MD). Quality control for the method was established with certified samples. Significantly higher mean values of Cu in serum, and urine samples of GMPs and GFPs, while lower value of Fe and I were observed as compared to control subjects (p < 0.015), respectively. The mean values of free triiodothyronine (FT3) and free thyroxin (FT4) were found to be lower in goitrous patients of both genders than in the age-matched healthy controls (p < 0.006 and 0.002), respectively, in contrast high mean values of thyroid-stimulating hormone (TSH) were detected in patients (p < 0.009), as compared to non-goitrous subjects. It was observed that the deficiencies of Fe, I, and thyroid hormone in goitrous patients could be influenced by efficiency of Cu.

Applicability of non-invasively collected matrices for human biomonitoring

With its inclusion under Action 3 in the Environment and Health Action Plan 2004-2010 of the European Commission, human biomonitoring is currently receiving an increasing amount of attention from the scientific community as a tool to better quantify human exposure to, and health effects of, environmental stressors. Despite the policy support, however, there are still several issues that restrict the routine application of human biomonitoring data in environmental health impact assessment. One of the main issues is the obvious need to routinely collect human samples for large-scale surveys. Particularly the collection of invasive samples from susceptible populations may suffer from ethical and practical limitations. Children, pregnant women, elderly, or chronically-ill people are among those that would benefit the most from non-invasive, repeated or routine sampling. Therefore, the use of non-invasively collected matrices for human biomonitoring should be promoted as an ethically appropriate, cost-efficient and toxicologically relevant alternative for many biomarkers that are currently determined in invasively collected matrices. This review illustrates that several non-invasively collected matrices are widely used that can be an valuable addition to, or alternative for, invasively collected matrices such as peripheral blood sampling. Moreover, a well-informed choice of matrix can provide an added value for human biomonitoring, as different non-invasively collected matrices can offer opportunities to study additional aspects of exposure to and effects from environmental contaminants, such as repeated sampling, historical overview of exposure, mother-child transfer of substances, or monitoring of substances with short biological half-lives.

Effect of zinc supplementation on the zinc level in serum and urine and their relation to thyroid hormone profile in male and female goitrous patients

BACKGROUND & AIMS

Zinc (Zn) is an essential element involved in many basic biochemical reactions in thyroid. The aims of present study is to evaluate the Zn status in biological samples and thyroid hormones levels in 60 goitrous male (GMPs) and 72 female patients (GFPs), before and after 6 months treatment with Zn supplementation and compared with non-goitrous subjects of both genders (M=106, F=120) of age range 16-30 years.

METHODS

The biological samples were analyzed for Zn concentration using flame atomic absorption spectrophotometer, following their microwave assisted acid digestion. Quality control for the methodology was established with certified samples and with those obtained by conventional wet acid digestion method on the same CRMs and real samples.

RESULTS

The results showed that the significantly lower mean values of Zn in serum, while high level urine samples of GMPs and GFPs were observed as compared to control subjects (p<0.005 and 0.007) respectively. The mean values of free triiodothyronine and thyroxin were found to be lower in goitrous patients of both genders than in the age matched healthy control (p<0.006 and 0.002) respectively, in contrast high mean values of thyroid stimulating hormone were detected in GMPs and GFPs (p<0.009).

CONCLUSION

It was observed that Zn status and serum thyroid hormone levels were improved in goitrous patients after six months treatment with Zn supplementation.

A review on the practical application of human biomonitoring in integrated environmental health impact assessment

Environmental health sciences focus on the link between the presence of contaminants in the environment and their relation with possible adverse health effects. Within this context, human biomonitoring (HBM) data have proven to be a valuable addition to, or have even surpassed, estimates of exposure based on environmental measures. Probably the main achievement of HBM data is that it provides an integrated overview of the pollutant dose any constituent is exposed to and incorporates bioaccumulation, excretion, half-life, and other potentially critical toxicokinetic parameters. In an integrated environmental health impact assessment framework, HBM serves as a pivotal point between environment and health, on the one hand leaning on environmental data to provide information on sources and pathways of exposure, and on the other hand clarifying hypotheses on the relationship between internal dose and prevalence of disease clusters. This study reflects the work performed in the INTARESE project (Integrated Assessment of Health Risk of Environmental Stressors in Europe). Because it was perceived that there was an overall lack of knowledge on the general methodology and potential application of HBM data in integrated environmental health impact assessment, an extensive review of literature was performed on past and current developments, potential, and applicability of HBM within the context of integrated environmental health impact assessment. This study covers three main topics that provide guidance for improved interpretation and application of HBM data: (1) sample collection and storage, (2) sample measurement, and (3) data interpretation. These main issues were discussed for 15 of the most common or relevant (classes of) chemicals. For more detailed information, the reader is pointed to the unabridged review (INTARESE, 2007), and consultation is available through the INTARESE web site (www.intarese.org).

Evaluation of iron in serum and urine and their relation with thyroid function in female goitrous patients

In many developing countries, women are at high risk of goiter and iron deficiency anemia (IDA). Iron deficiency adversely affects thyroid metabolism and may decrease the efficiency of thyroid hormones in areas of endemic goiter. The aim of the present study was to compare the level of iron (Fe) in biological samples (serum and urine) and serum thyroid hormones, thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxin (FT4) of goitrous female patients (GFPs; n = 69) with those of nongoitrous women as control subjects (n = 117), age range 21-45 years. The biological samples were analyzed for Fe concentration using flame atomic absorption spectrophotometer, prior to microwave-assisted wet acid digestion. The validity and accuracy of the method was checked by the certified sample and with those obtained by conventional wet acid digestion method on the same CRM and real samples. The overall recoveries of Fe in serum and urine were found in the range of 97.2-98.6% of certified values. The results of this study showed that the mean values of Fe in serum and urine samples of GFPs were significantly reduced as compared to control subjects (p = 0.002 and p = 0.015, respectively). The mean values of FT3 and FT4 were found to be lower in GFPs than in the age-matched healthy control women; in contrast, high mean values of TSH were detected in GFPs (p = 0.003). There was a positive correlation between serum Fe concentration and TSH (r = 0.85, p = 0.01), FT3 (r = 0.95, p = 0.003), and FT4 levels (r = 0.98, p = 0.007) in GFPs. It was observed that iron deficiency is prevalent in GFPs, so the need of Fe supplementation will be required to improve the efficacy of thyroid metabolism in goitrous women.

Arsenic Speciation Analysis in Human Saliva

Background: Determination of arsenic species in saliva is potentially useful for biomonitoring of human exposure and studying arsenic metabolism. Arsenic speciation in saliva has not been reported previously.

Methods: We separated arsenic species in saliva using liquid chromatography (LC) and quantified them by inductively coupled plasma mass spectrometry. We further confirmed the identities of arsenic species by LC coupled with electrospray ionization tandem mass spectrometry. These methods were successfully applied to the determination of arsenite (AsIII), arsenate (AsV), and their methylation metabolites, monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV), in &gt;300 saliva samples collected from people who were exposed to varying concentrations of arsenic.

Results: The mean (range) concentrations (μg/L) in the saliva samples from 32 volunteers exposed to background levels of arsenic were AsIII 0.3 [not detectable (ND) to 0.7], AsV 0.3 (ND to 0.5), MMAV 0.1 (ND to 0.2), and DMAV 0.7 (ND to 2.6). Samples from 301 people exposed to increased concentrations of arsenic in drinking water showed detectable AsIII in 99%, AsV in 98%, MMAV in 80%, and DMAV in 68% of samples. The mean (range) concentrations of arsenic species in these saliva samples were (in μg/L) AsIII 2.8 (0.1–38), AsV 8.1 (0.3–120), MMAV 0.8 (0.1–6.0), and DMAV 0.4 (0.1–3.9). Saliva arsenic correlated with drinking water arsenic. Odds ratios for skin lesions increased with saliva arsenic concentrations. The association between saliva arsenic concentrations and the prevalence of skin lesions was statistically significant (P &lt;0.001).

Conclusions: Speciation of AsV, AsIII, MMAV, and DMAV in human saliva is a useful method for monitoring arsenic exposure.

A comparison of three solvent-free techniques coupled with gas chromatography for determining trihalomethanes in urine samples

The analysis of volatile organic compounds in samples of biological fluids characterized by complex matrices is highly challenging. This paper presents a comparison of the results obtained in this field using three solvent-free techniques: thin-layer headspace with autogenous generation of liquid sorbent (TLHS) and membrane separation of the trace substances (pervaporation, PV), both of which are coupled to direct aqueous injection gas chromatography-electron capture detection (TLHS-DAI-GC-ECD and PV-DAI-GC-ECD), as well as conventional static headspace analysis followed by GC analysis with ECD detection (HS-GC-ECD). Basic validation parameters of the HS-GC-ECD, TLHS-DAI-GC-ECD and PV-DAI-GC-ECD procedures were calculated for water and urine samples. The calibration curves for all procedures were linear within the concentration range examined. The intermediate precisions of the procedures were good and reached about 10% (for all analytes) for HS-GC-ECD and TLHS-DAI-GC-ECD. The poorest results were obtained for PV-DAI-GC-ECD: about 20% for all analytes. The lowest method detection limits were obtained for the TLHS-DAI-GC-ECD procedure: below 0.0022 microg/L for all analytes. The enrichment factors did not differ significantly between water and urine samples, indicating little or no matrix effect in all procedures.