Tin is a naturally occurring heavy metal that occurs in the environment in both inorganic and organic forms. Human exposure to tin is almost ubiquitous; however, surprisingly little is known about factors affecting environmental tin exposure in humans. This study analyzed demographic, socioeconomic and lifestyle factors associated with total urinary tin levels in adults (N = 3522) and children (N = 1641) participating in the National Health and Nutrition Examination Survey (NHANES) 2011–2014, a nationally representative health survey in the United States. Urinary tin levels, a commonly used biomarker of environmental tin exposure, were determined by inductively coupled plasma mass spectrometry (ICP-MS). Detection frequencies of tin were 87.05% in adults and 91.29% in children. Median and geometric mean levels of urinary tin in the adult population were 0.42 μg/L and 0.49 μg/L, respectively. For children, median and geometric mean levels of urinary tin were 0.60 μg/L and 0.66 μg/L, respectively. Age was identified as an important factor associated with urinary tin levels. Median tin levels in the ≥60 year age group were almost 2-fold higher than the 20–39 year age group. Tin levels in children were 2-fold higher than in adolescents. Race/ethnicity and household income were associated with tin levels in both adults and children. In addition, physical activity was inversely associated with urinary tin levels in adults. These results demonstrate that total tin exposures vary across different segments of the general U.S. population. Because the present study does not distinguish between organic and inorganic forms of tin, further studies are needed to better characterize modifiable factors associated with exposures to specific tin compounds, with the goal of reducing the overall exposure of the U.S. population.

Urban agriculture plays an important role in sustainable food supply. However, because of the atmospheric pollution and soil contamination associated with urban areas, this activity may be of concern. In fact, contamination of soil with metals and the transference of contaminants to vegetables can represent health and safety risks associated with urban agriculture. The objective of this study was to evaluate the concentrations of selected trace metals (cadmium, copper and lead) in three lettuce cultivars produced in three different urban gardens in the metropolitan region of Belo Horizonte, Brazil and their respective soils. Samples of lettuce and soil were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (AAS-GF), respectively, and their transfer coefficients were calculated. The methods were optimized and were fit for the purpose. Copper was the prevalent metal found in soils and lettuce, with an average of 27.9 ± 13.9 and 0.608 ± 0.157 mg kg⁻¹ respectively, followed by lead (19.4 ± 7.7 and 0.037 ± 0.039 mg kg⁻¹), and cadmium (0.16 ± 0.03 and 0.009 ± 0.005 mg kg⁻¹). Cadmium presented the largest transfer coefficients, ranging from 0.34 to 1.84 with an average of 0.92 ± 0.45, which may indicate a potential risk of accumulation in vegetables in the case of high soil contamination. A significant positive correlation was observed (p < 0.01) between cadmium in lettuce and in soil. Even though lead concentrations varied in the soils from the different urban areas, ranging from 11.88 to 30.01 mg kg⁻¹, no significant difference (p < 0.05) was found among the lettuce, probably due to its low mobility (transfer coefficient = 0.02). The copper and cadmium levels found in lettuce indicate safe lettuce production in the three urban gardens.

CuO engineered nanoparticles (NPs) are of increasing concern due to their extensive use in daily life and adverse effect on aquatic organisms. The investigations on the toxicity of CuO NPs to aquatic plants through uptake from roots versus fronds are limited. This paper discusses the interactions of CuO NPs with Lemna minor, a floating plant. After CuO NPs (150 μg L⁻¹) exposure for 7 days, the frond number, frond surface area and dry weights of whole plants significantly decreased by 32%, 47% and 33%; the responses were dose-dependent. Microscopy imaging showed that the epidermis was severely damaged in fronds, edges were severely sloughed off and cell integrity was damaged in roots. Shrinkage of both chloroplast and starch grains were observed in the frond cells. Internalization of CuO NPs in root and frond cells during CuO NPs (1 mg L⁻¹) exposure was confirmed with the root Cu levels of Lemna minor being three times higher than the fronds by using transmission electron microscopy and flame atomic absorption spectrophotometry. Reactive oxygen species, mainly H₂O₂ (increased by 56%) and ·OH (increased by 57%), accumulated in Lemna minor tissues in response to CuO NPs exposure. Moreover, chloroplasts were confirmed as a site of ROS production. These findings are helpful for better understanding the biological responses of aquatic plants upon NPs exposure.

Metal enrichment of road dust is well characterized but available data on the bioaccessibility of metals in particle size fractions relevant to human respiratory health remain limited. The study goal was to investigate the bioaccessibility of platinum group elements (PGE), which are used as catalysts in automotive exhaust converters, in the inhalable fraction of road dust. Street sweepings were provided by the City of Toronto, Canada, collected as part of its Clean Roads to Clean Air program.The particle size relevance of road dust for inhalation exposures was confirmed using a laser diffraction particle size analyzer (mean Dx(50): 9.42 μm). Total PGE were determined in both bulk and inhalable fractions using nickel sulfide (NiS) fire-assay and instrumental neutron-activation analysis (INAA). PGE lung solubility was examined for the inhalable fraction using Gamble’s extraction. Sample digests were co-precipitated with Te-Sn, to pre-concentrate and isolate PGE, prior to their measurement using inductively coupled plasma mass spectrometry (ICP-MS).Total PGE concentrations were enriched in the inhalable fraction of road sweepings. Geomean concentrations in the inhalable fraction were: palladium (Pd) (152 μg/kg), platinum (Pt) (55 μg/kg), rhodium (Rh) (21 μg/kg) and iridium (Ir) (0.23 μg/kg). Osmium (Os) concentrations were below the limit of detection (LOD). Bioaccessible PGEs (n = 16) using Gamble’s solution were below LOD for Ir and ruthenium (Ru). For the remainder, the geomean % bioaccessibility was highest for platinum (16%), followed by rhodium (14%) and palladium (3.4%). This study provides evidence that PGE in road dust are bioaccessible in the human lung.

There is increasing evidence linking levels of trace elements (TEs) in adipose tissue with certain chronic conditions (e.g., diabetes or obesity). The objectives of this study were to assess concentrations of a selection of nine essential and possibly-essential TEs in adipose tissue samples from an adult cohort and to explore their socio-demographic, dietary, and lifestyle determinants. Adipose tissue samples were intraoperatively collected from 226 volunteers recruited in two public hospitals from Granada province. Trace elements (Co, Cr, Cu, Fe, Mn, Mo, Se, V, and Zn) were analyzed in adipose tissue by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Data were collected on socio-demographic characteristics, lifestyle, diet, and health status by face-to-face interview. Predictors of TE concentrations were assessed by using multivariable linear and logistic regression. All TEs were detected in all samples with the exception of Se (53.50%). Iron, zinc, and copper showed the highest concentrations (42.60 mg/kg, 9.80 mg/kg, and 0.68 mg/kg, respectively). Diet was the main predictor of Cr, Fe, Mo, and Se concentrations. Body mass index was negatively associated with all TEs (β coefficients = −0.018 to −0.593, p = 0.001–0.090) except for Mn and V. Age showed a borderline-significant positive correlation with Cu (β = 0.004, p = 0.089). Residence in a rural or semi-rural area was associated with increased Co, Cr, Fe, Mo, Mn, V and Zn concentrations and with β coefficients ranging from 0.196 to 0.544 (p < 0.05). Furthermore, individuals with higher educational level showed increased Cr, Co, Fe and V concentrations (β coefficients = 0.276–0.368, p = 0.022–0.071). This is the first report on the distribution of these TEs in adipose tissue and on their determinants in a human cohort and might serve as an initial step in the elucidation of their clinical relevance.

The long-term associations between multiple metals and incident diabetes are uncertain. We aimed to examine the relationship between plasma concentrations of 23 metals and the incidence of type 2 diabetes among Chinese senior adults. We quantified fasting plasma concentrations of 23 metals by inductively coupled plasma mass spectrometry among 1039 incident diabetes cases and 1039 controls (age and sex matched) nested in a prospective study, the Dongfeng-Tongji cohort. Both cases and controls were free of diabetes at baseline (2008–2010), incident diabetes were identified using the following criteria: fasting glucose ≥ 7.0 mmoL/l; or hemoglobin A1c (HbA1c) ≥ 6.5%; or self-reported physician diagnosis of diabetes or use of anti-diabetic medication during the follow-up visits in 2013. In the conditional logistic regression models, the multivariable adjusted ORs (95% CIs) of diabetes across quartiles (Q1–Q4) of metal concentrations were as follows: titanium, 1.00, 0.92, 1.31, 1.38 (1.00–1.91, Ptrend = 0.011); selenium, 1.00, 1.08, 1.45, 1.27 (0.93–1.74, Ptrend = 0.05); and antimony, 1.00, 0.79, 0.77, 0.60 (0.44–0.83, Ptrend = 0.002). Arsenic was significantly associated with diabetes in the crude model (ORs comparing extreme quartiles 1.30; 1.02–1.65; Ptrend = 0.006), but was not significant after adjustment for socio-demographic factors. No significant associations were found for other metals. In conclusion, titanium and selenium were positively while antimony was negatively associated with incident diabetes.

We describe a batch-extraction with simulated digestive fluid (salivary fluid, gastric fluid and intestinal fluid) to estimate the bioaccessibility of inhaled trace metals (TMs) in particulate matter less than 10 and 2.5 μm in aerodynamic diameter (PM₁₀ and PM₂.₅). Concentrations of the assayed TMs (As, Cd, Cr, Ni, Mn, Cu, Zn, Sb, Hg and Pb) were determined in PM₁₀ and PM₂.₅ samples by inductively coupled plasma-mass spectrometry. The TMs with the largest soluble fractions for airborne PM collected from winter and summer in saliva were Mn and Sb, respectively; in seasons this became Co in gastric fluid and Cu in intestinal fluid. Clearly, bioaccessibility is strongly dependent on particle size, the component of simulated digestive fluids (e.g., pH, digestive enzymes pepsin and trypsin), and the chemical properties of metal ions. The particle size and seasonal variation affected the inhaled bioaccessible fraction of PM-bound TMs during mucociliary clearance, which transported PM from the tracheal and the bronchial region to the digestive system. This study provides direct evidence for TMs in airborne PM being bioaccessible TMs are likely to possess an enhanced digestive toxic potential due to airborne PM pollution.

Previously, we showed that manganese (Mn) levels in settled dust in elementary schools increased at a rate of 34.1% per km closer to a ferro-manganese alloy plant in the rainy season. In this study, we investigated how this environmental pollution indicator varied in the dry season and if there was an association with Mn biomarker levels in school-aged children. Dust samples were collected with passive samplers (disposable Petri dishes) placed in interior and exterior environments of 14 elementary schools. Occipital hair, toenails and blood samples were collected from 173 students aged 7–12 years from three of these schools, with varying distance from the industrial plant. Mn and lead (Pb) levels were measured by graphite furnace atomic absorption spectrometry. Mn concentration geometric means (GM) in dust fall accumulation in interior environments of schools located at 2, 4, 6 and > 6 km-radii from the plant were 2212, 584, 625 and 224 μg Mn/m2/30 days, respectively. The modelled rate of change of dust Mn levels decreases by 59.8% for each km further from the plant. Pb levels in settled dust varied between 18 and 81 μg/m2/30 days with no association with distance from the plant. Blood lead levels median (range) were 1.2 μg/dL (0.2–15.6), of which 97.8% were <5 μg/dL. Mn in hair and toenails were 0.66 μg/g (0.16–8.79) and 0.86 μg/g (0.15–13.30), respectively. Mn loading rates were positively associated with log MnH (β = 1.42 × 10−5, p < 0.001) after adjusting for children's age; and also with log MnTn (β = 2.31 × 10−5, p < 0.001) independent of age. Mn loading rates explained 18.5% and 28.5% of the variance in MnH and MnTn levels, respectively. School-aged children exposure to Mn, independently of age, increases significantly with school proximity to the ferro-manganese alloy plant.

Orofacial clefts (OFCs) have multifactorial etiologies. Prenatal exposure to heavy metals can induce OFCs in animal models, but evidence from studies of human subjects is scarce. We examined whether concentrations of mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As) in placental tissues are associated with risk for OFCs in offspring. This population-based case-control study included 103 newborns affected by OFCs with available placental tissues and 206 controls randomly selected from 509 non-malformed newborns with available placenta samples, recruited in five rural counties in northern China. Sociodemographic information was collected using a structured questionnaire in face-to-face interviews. The concentrations of Hg, Cd, Pb, and As in placental tissues were analyzed using an inductively coupled plasma-mass spectrometry in helium mode. The median concentrations of Hg (7.4 ng/g), Cd (57.1 ng/g), and Pb (96.1 ng/g) were all statistically significantly higher in OFC cases than in controls (Hg 5.5 ng/g, Cd 38.6 ng/g, and Pb 67.9 ng/g, respectively); no differences were observed between the two groups in median concentrations of As. Concentrations above the median for all subjects were associated with a 2.33-fold (95% confidence interval [CI] 1.33–2.09) increased OFC risk for Cd and a 3.08-fold (95% CI 1.74–5.47) increased risk for Pb. The risk for OFCs increased with concentration tertiles, with an adjusted odds ratio of 3.06 (95% CI 1.36–6.88) for the second tertile and 8.18 (95% CI 6.64–18.37) for the highest tertile of Cd, and 3.88 (95% CI 1.78–8.42) for the second tertile and 5.17 (95% CI 2.37–11.29) for the highest tertile of Pb. The association between Hg concentration and OFC risk was borderline nonsignificant after adjusting for confounding factors. Prenatal exposure to Cd and Pb, as reflected by their concentrations in placental tissues, is associated with an increased risk for neonatal OFCs.

Thirty bottom sediment samples were collected from northern Hurghada coast, Red Sea, Egypt to evaluate the level of anthropogenic pollutants, using enrichment factor (EF), potential ecological risk index (PERI), soil pollution index (SPI), potential contamination index (Cp) and multivariate statistical analysis (correlation analysis, principal component analysis, and hierarchical cluster analysis). Fe, Mn, Zn, Pb, Ni, Cu, Co and Cd were analyzed by Atomic Absorption Spectrophotometer. Results indicated that the average values of Pb and Cd were greater than the ones recorded from many other worldwide coastal areas. The studied sediments are extremely severe enrichment with Pb and Cd (EF > 50), severe enrichment with Zn (EF = 10–25), very high risk with Cd (PERI ≥ 320), high risk with Pb (160 ≤ PERI ˂ 320), highly contaminated with Pb (SPI > 3), a severe contamination with Pb (Cp > 3). The accumulation of pollutants is associated with the muddy and fine sediment; especially the studied area is a semi-closed bay, characterized by long time of water retention. Possible sources of metals pollution in the studied area are shipment operations and anticorrosive and antifouling paints, dredging and land filling, municipal wastewater from tourist centers and fishermen cargo boats.