Urinary reference ranges and exposure profile for lithium among an Italian paediatric population

Biomonitoring of Exposure to Urban Pollutants and Oxidative Stress during the COVID-19 Lockdown in Rome Residents

Background: The objective of this study is to evaluate the effects of traffic on human health comparing biomonitoring data measured during the COVID-19 lockdown, when restrictions led to a 40% reduction in airborne benzene in Rome and a 36% reduction in road traffic, to the same parameters measured in 2021. Methods: Biomonitoring was performed on 49 volunteers, determining the urinary metabolites of the most abundant traffic pollutants, such as benzene and PAHs, and oxidative stress biomarkers by HPLC/MS-MS, 28 elements by ICP/MS and metabolic phenotypes by NMR. Results: Means of s-phenylmercaputric acid (SPMA), metabolites of naphthalene and nitropyrene in 2020 are 20% lower than in 2021, while 1-OH-pyrene was 30% lower. A reduction of 40% for 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodGuo) and 60% for 8-oxo-7,8-dihydroguanine (8-oxoGua) were found in 2020 compared to 2021. The concentrations of B, Co, Cu and Sb in 2021 are significantly higher than in the 2020. NMR untargeted metabolomic analysis identified 35 urinary metabolites. Results show in 2021 a decrease in succinic acid, a product of the Krebs cycle promoting inflammation. Conclusions: Urban pollution due to traffic is partly responsible for oxidative stress of nucleic acids, but other factors also have a role, enhancing the importance of communication about a healthy lifestyle in the prevention of cancer diseases.

Oxidative Stress Biomarkers in Urine of Metal Carpentry Workers Can Be Diagnostic for Occupational Exposure to Low Level of Welding Fumes from Associated Metals

Urinary concentrations of 16 different exposure biomarkers to metals were determined at the beginning and at the end of a working shift on a group of workers in the metal carpentry industry. Five different oxidative stress biomarkers were also measured, such as the oxidation products of RNA and DNA metabolized and excreted in the urine. The results of workers exposed to metals were compared to those of a control group. The metal concentrations found in these workers were well below the occupational exposure limit values and exceeded the mean concentrations of the same metals in the urine of the control group by a factor of four at maximum. Barium (Ba), mercury (Hg), lead (Pb) and strontium (Sr) were correlated with the RNA oxidative stress biomarker, 8-oxo-7, 8-dihydroguanosine (8-oxoGuo), which was found able to discriminate exposed workers from controls with a high level of specificity and sensitivity. The power of this early diagnostic technique was assessed by means of the ROC curve. Ba, rubidium (Rb), Sr, tellurium (Te), and vanadium (V) were correlated with the level of the protein oxidation biomarker 3-Nitrotyrosine (3-NO₂Tyr), and Ba, beryllium (Be), copper (Cu), and Rb with 5-methylcytidine (5-MeCyt), an epigenetic marker of RNA damage. These effect biomarkers can help in identifying those workers that can be defined as "occupationally exposed" even at low exposure levels, and they can provide information about the impact that such doses have on their health.

Application of Lithium Assay kit LS for quantification of lithium in whole blood and urine

A commercially available kit for the quantitation of lithium, the Lithium Assay kit LS, was originally developed to measure lithium in serum or plasma using a conventional microplate reader. We investigated whether use of the kit could be extended to quantify lithium in whole blood and urine samples collected at autopsy. The calibration curve for whole blood showed good linearity ranging from 0.5 to 20 µg/mL with a coefficient of determination of 0.998 when samples were pretreated with methanol followed by acetonitrile. Moreover, for urine, we obtained excellent linearity with a coefficient of determination of 0.999 without any pretreatment. The accuracies and precisions were 106.3-174.7% and 1.9-18.1% for whole blood and 83.3-118.8% and 5.7-33.8% for urine. The values in the lower concentration range (0.5-1 µg/mL) were not satisfactory, whereas those in the higher range (2-20 µg/mL) were acceptable. The Lithium Assay kit LS was successfully applied to the measurement of lithium in whole blood and urine samples collected at autopsies. This method appears to be useful for forensic toxicological investigations because of its simplicity and speed.

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.

Urinary Oxidative Stress Biomarkers in Workers of a Titanium Dioxide Based Pigment Production Plant

Titanium dioxide is produced or imported into the EU for over one million tons/year. The International Agency for Research on Cancer (IARC) classification is 2B, a possible inhalation carcinogen for humans. This study evaluates urinary biomarkers of oxidative stress in workers of a plant producing TiO2 pigment powder, having 0.25 µm average particle size and an ultrafine fraction, compared to unexposed subjects. Urine samples were collected from forty workers before and after the shift, from six employees of the same company and eighteen volunteers from the same geographical area. Titanium and other metals concentrations were measured by ICP-MS, while DNA, RNA, and protein oxidation products by HPLC/MS-MS. A statistically significant increase was found for the urinary concentration of Al, Cd, Cr, Cu, Fe, Mn, Pb, Ti, and Zr, and for all biomarkers of oxidative stress in post-shift workers' urine samples. Urinary concentrations after the working shift were higher than for employees and volunteers pooled together for Cd, Mn, and Zr, and for the oxidative stress biomarkers 8-oxoGuo, 8-oxodGuo, and 3NO2Tyr. Biomonitoring studies on dose and effect biomarkers for TiO2 occupational exposure provide information useful for protecting workers' health even in conditions that comply with health and safety standards, highlighting reversible effects of chronic exposure at very low doses.

Element Levels and Predictors of Exposure in the Hair of Ethiopian Children

Children's development and health may be affected by toxic heavy metal exposure or suboptimal essential element intake. This study aimed to provide updated information regarding the concentrations of 41 elements in children's hair (aged under 18) living in a rural area of the Benishangul-Gumuz region, Ethiopia. The highest average levels (as a geometric mean) for toxic heavy metals were obtained for Al (1 mg kg^-1), Pb (3.1 mg kg^-1), and Ni (1.2 mg kg^-1), while the lowest concentrations among the essential elements were found for Co (0.32 mg kg^-1), Mo (0.07 mg kg^-1), Se (0.19 mg kg^-1), and V (0.8 mg kg^-1). Hair analysis was combined with a survey to evaluate relationships and variations among subgroups and potential metal exposure predictors. Females showed significantly higher concentrations for most hair elements, excluding Zn, than males, and the 6-11 years age group reported the highest levels for Be, Ce, Co, Fe, La, Li, Mo, and Na. The main predictors of exposure to toxic elements were fish consumption for Hg and drinking water for Ba, Be, Cs, Li, Ni, Tl, and U. The data from this study can be used to develop prevention strategies for children's health and protection in developing countries.

Effectiveness of Different Sample Treatments for the Elemental Characterization of Bees and Beehive Products

Bee health and beehive products’ quality are compromised by complex interactions between multiple stressors, among which toxic elements play an important role. The aim of this study is to optimize and validate sensible and reliable analytical methods for biomonitoring studies and the quality control of beehive products. Four digestion procedures, including two systems (microwave oven and water bath) and different mixture reagents, were evaluated for the determination of the total content of 40 elements in bees and five beehive products (beeswax, honey, pollen, propolis and royal jelly) by using inductively coupled plasma mass and optical emission spectrometry. Method validation was performed by measuring a standard reference material and the recoveries for each selected matrix. The water bath-assisted digestion of bees and beehive products is proposed as a fast alternative to microwave-assisted digestion for all elements in biomonitoring studies. The present study highlights the possible drawbacks that may be encountered during the elemental analysis of these biological matrices and aims to be a valuable aid for the analytical chemist. Total elemental concentrations, determined in commercially available beehive products, are presented.

Occupational Exposure Assessment of Major and Trace Elements in Human Scalp Hair Among a Group of Eritrean Workers

The aim of the study was to evaluate occupational exposure to 40 elements among a group of Eritrean adults employed at the Medeber metal market by analysing human scalp hair samples and by investigating the role of some predictors (gender, age, and body mass index-BMI) on their levels. Scalp hair samples were collected from 60 subjects (32 subjects working at the Medeber metal market and 28 subjects not working at Medeber and not employed in other industrial or artisanal activities) and were analysed through inductively coupled plasma mass spectrometry to determine the contents of 40 major and trace elements. Information on participants was collected via questionnaire. Significant differences were found in the hair levels of certain elements between subjects working at the Medeber metal market and subjects not exposed. In particular, working at the Medeber metal market increased hair levels of Be, B, Cu, Zn, Mo, Cd, Sb, Tl, Pb, and Fe from 25 to 100%, while reduced Na, K, and Rb levels from 30 to 50%. With multivariate adjustment for age, gender, and BMI, the results confirm that working at Medeber significantly increased the hair levels of Cu, Zn, Sb, Pb, and Fe. This finding reveals the need for more accurate and routine biomonitoring surveys and the necessity of health promotion campaigns both for local decision-makers and workers to increase health promotion and safety in this workplace.

Biomonitoring of Mercury in Hair among a Group of Eritreans (Africa)

Small-scale or artisanal mining, using gold-mercury amalgamation to extract gold from ore, is a significant source of exposure for the workers and nearby populations. Few studies on hair mercury (Hg) have been conducted in Africa despite the fact that Africa has several gold deposits. No studies have been conducted in Eritrea that is one of the emerging gold producing countries in Africa. The aim of the study was to assess the Hg concentration in hair samples (n = 120) of a population living in Asmara, capital of Eritrea, and to evaluate the influence of some factors on the Hg levels in hair. Information on age, height, weight, occupation, smoking and fish consumption of participants were collected via questionnaire. Hair Hg concentration was significantly higher among women compared to men (p < 0.001) and among women preparing spicy products in Medeber market compared to those who did other jobs (p = 0.010). These results highlight the need for routine biomonitoring surveys and for health promotion campaigns devoted to local decision makers and workers.

Derivation of whole blood biomonitoring equivalents for lithium for the interpretation of biomonitoring data

INTRODUCTION

Lithium salts have numerous industrial uses and are also used in the treatment of bipolar disorders. The main source of lithium exposure to the general population is drinking water and foods. Lithium is nephrotoxic at higher doses. Thus, oral exposure guidelines for lithium have been derived, including ICH's permitted daily exposure (PDE = 0.008 mg lithium/kg-bw/day) adopted by Health Canada and the United States Environmental Protection Agency's (U.S. EPA) provisional peer reviewed toxicity value (PPRTV = 0.002 mg lithium/kg-bw/day), both based on human data.

OBJECTIVE

To derive whole blood biomonitoring equivalents (BEs) associated with PDE and PPRTV to interpret population-level biomonitoring data in health risk context.

METHOD

A simple kinetic relationship based on plasma clearance value (0.5 L/kg-bw/day) and the oral absorption fraction (100%) was used to derive blood BEs for PDE and PPRTV.

RESULTS

This analysis resulted in BE values in plasma and whole blood of 16 and 10 μg/L, respectively, based on the PDE values developed by the Health Canada and of 4.2 and 2.7 μg/L, respectively, based on the PPRTV developed by U.S. EPA.

CONCLUSION

The derived BE values can be used to interpret population-level biomonitoring data.

Further Insights on Predictors of Environmental Tobacco Smoke Exposure during the Pediatric Age

Background: The smoking ban in public places has reduced Environmental Tobacco Smoke (ETS) exposure for non-smokers, but despite this, domestic environments still remain places at high risk of exposure, and, today, about 40% of children worldwide are exposed to ETS at home. The aims of the study are to investigate the contribution of several factors on ETS exposure among a group of Italian children and to evaluate the changes in smoking precautions adopted at home when the smoker is the mother, the father, or both parents, respectively. Methods: A cross-sectional study was performed on a sample of 519 Italian schoolchildren. Information was collected via a questionnaire. Results: 41.4% of the participants lived with at least one smoker. Almost half of the children exposed to ETS lived with one or more smokers who do not observe any home smoking ban. Lower maternal or paternal educational levels significantly increase the risk of ETS exposure at home and the "worst case" is represented by both parents who smoke. Conclusions: More effective preventive interventions are needed to protect children from ETS exposure. Some interventions should be specifically dedicated to smokers with a low educational level and to mothers that smoke.

A prophylactic multi-strain probiotic treatment to reduce the absorption of toxic elements: In-vitro study and biomonitoring of breast milk and infant stools

Potential exposure to toxic elements initially occurs during gestation and after birth via breast milk, which is the principal source of nutrients for infants during the first months of life. In this study, we evaluated whether maternal oral supplementation with a multi-strain probiotic product can protect infants from exposure to arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) via breast milk. In-vitro studies of the bacterial strains present in this probiotic product showed a high bacterial tolerance for As, Cd, Hg, and Pb, and good binding capacity for Cd, Hg, and Pb (72%, 81%, and 64%, respectively) within 1 h of contact. We evaluated concentrations (5 mg L^-1 for Cd and Pb, and 2 mg L^-1 for Hg) that largely exceeded the provisional tolerable weekly intake of these toxic elements via food or water applicable for human consumption. Changes in the levels of these elements in breast milk and newborn stools were evaluated in the control (orally supplemented with placebo) and experimental (orally supplemented with probiotic) groups at birth (t0), 15 days (t15), and 30 days (t30) after delivery. Elemental analysis of breast milk did not show significant differences between the control and experimental groups at different stages of lactation; however, stool samples obtained from newborns of mothers supplemented with the probiotic product showed that Cd levels were significantly reduced (by 26%) at t15 compared with the levels of the controls. Our data did not show an association between concentration of toxic elements in breast milk and that in newborn stools. Indeed, the concentration of Cd, Hg, and Pb in breast milk decreased during the lactation period, whereas the levels of these elements in newborn stools were stable over time. Although our in-vitro data indicate that the consortium of these probiotic strains can absorb toxic compounds, this study was limited by its small sample size and potential uncontrolled confounding effects, such as maternal diet and lifestyle. Therefore, we could not confirm whether prophylactic use of this probiotic product can reduce the absorption of toxic elements. The risk assessment in the studied population evidenced a margin of exposure (MOE) of 1, or between 1 and 10 for Pb, and lower than 50 for As. This poses a potential risk for breastfed infants, indicating that interventions aimed to avoid breastfeeding-related health risks remain a major challenge in public health.

Lithium levels in tap water and psychotic experiences in a general population of adolescents

Recently, several epidemiologic studies have reported that lithium in drinking water may be associated with lower rates of suicide mortality, lower incidence of dementia, and lower levels of adolescents' depression and aggression at the population level. However, to our knowledge, no study has investigated lithium level in tap water in relation to psychotic experiences in a general population of adolescents. This is the first study to investigate this using a large dataset. Information on psychotic experiences, distress associated with these experiences, and depressive symptoms were collected in 24 public junior high schools in Kochi Prefecture in Japan. Samples were collected from sources that supplied drinking water to schools, and lithium levels were measured using atomic absorption spectrophotometry. The association of lithium levels with psychotic experiences, considering distress as a degree of severity, was examined using an ordinal logistic regression model with schools and depressive symptoms as random effects. In total, 3040 students responded to the self-reporting questionnaire (response rate: 91.8%). Lithium levels in tap water were inversely associated with psychotic experiences (p = 0.021). We concluded that lithium level in tap water was inversely associated with psychotic experiences among a general population of adolescents and may have a preventive effect for such experiences and distress.

Optimization and validation of a fast digestion method for the determination of major and trace elements in breast milk by ICP-MS

Breast milk guarantees all the nutrients required by infants during their first few months of life and remains the most important food source for their health and growth. However, the mother may transfer potentially toxic chemicals to the suckling infant through breastfeeding. The aim of this study was to optimize and validate a fast method for the determination of a total content of 34 elements (Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Se, Si, Sn, Sr, Te, Ti, Tl, U, V, and Zn) in liquid and lyophilized breast milk. The samples were subjected to HNO₃:H₂O₂ (2:1) digestion in an open vessel heated in a water bath (WBD; 80 °C) and subsequently analysed by quadrupole inductively coupled plasma mass spectrometry equipped with a collision-reaction interface. The performance of the proposed method was evaluated in terms of selectivity, detection and quantification limits, linearity, accuracy, and robustness by using standard reference materials and filed samples of breast milk. Compared to microwave-assisted acid digestion, the proposed open vessel digestion allows a significant reduction in treatment time and sample manipulation, while maintaining a similar analytical performance. Masses of 0.5 g of breast milk were efficiently digested with the WBD treatment allowing a residual carbon content lower than 60 mg L^-1 and a residual acidity lower than 0.87 mol L^-1 in final digested samples. Thus, it shows great potential for application to routine analysis. The method provides satisfactory detection limits and good performance (trueness and recovery percentages 80-111%; coefficient of variation <10%; and relative repeatability <15%) and allows a high sample throughput for multi-elemental determination in human biomonitoring studies.

Reference Intervals for Urinary Cotinine Levels and the Influence of Sampling Time and Other Predictors on Its Excretion Among Italian Schoolchildren

(1) Background: Environmental Tobacco Smoke (ETS) exposure remains a public health problem worldwide. The aims are to establish urinary (u-) cotinine reference values for healthy Italian children, to evaluate the role of the sampling time and of other factors on children’s u-cotinine excretion. (2) Methods: A cross-sectional study was performed on 330 children. Information on participants was gathered by a questionnaire and u-cotinine was determined in two samples for each child, collected during the evening and the next morning. (3) Results: Reference intervals (as the 2.5th and 97.5th percentiles of the distribution) in evening and morning samples were respectively equal to 0.98–4.29 and 0.91–4.50 µg L⁻¹ (ETS unexposed) and 1.39–16.34 and 1.49–20.95 µg L⁻¹ (ETS exposed). No statistical differences were recovered between median values found in evening and morning samples, both in ETS unexposed and exposed. Significant predictors of u-cotinine excretions were ponderal status according to body mass index of children (β = 0.202; p-value = 0.041 for evening samples; β = 0.169; p-value = 0.039 for morning samples) and paternal educational level (β = −0.258; p-value = 0.010; for evening samples; β = −0.013; p-value = 0.003 for morning samples). (4) Conclusions: The results evidenced the need of further studies for assessing the role of confounding factors on ETS exposure, and the necessity of educational interventions on smokers for rising their awareness about ETS.