Using human hair and nails as biomarkers to assess exposure of potentially harmful elements to populations living near mine waste dumps

Human Exposure to Heavy Metals over the Last 100 Years

The primary objective of the presented research was to assess the impact of intense global economic development, over the last 100 years, on the bioaccumulation of heavy metals in the human body. This evaluation was conducted based on the measurement of heavy metals in human hair samples collected 100 years ago in present-day southern Poland.In this study, concentrations of lead (Pb), cadmium (Cd), arsenic (As), zinc (Zn), copper (Cu), iron (Fe), and selenium (Se) were measured in 61 hair samples,28 of which were obtained from individuals who lived 100 years ago, while the remaining 33 constituted the contemporary control group. The concentrations were determined using a triple quadrupole inductively coupled plasma mass spectrometer (Agilent 8900). Statistical analysis of the obtained results was conducted using the Principal Cmponent Analysis and the non-parametric Mann-Whitney test. In the case of As, Pb, Cd, and Fe, the concentrations were significantly higher in individuals who lived 100 years ago compared to those living today. Over this period, the median concentrations were shown to have decreased by 95%, 94%, 85%, and 69% for As, Pb, Cd, and Fe, respectively. No statistically significant differences were observed for Cu, Zn, and Se. The results obtained for Pb, Cd, As, and Fe unequivocally indicate that the population studied from 100 years ago was more exposed to internal contamination with these metals than people who live nowadays.

Insights into the Mechanism of Selective Removal of Heavy Metal Ions by the Pulsed/Direct Current Electrochemical Method

Heavy metal pollution treatment in industrial wastewater is crucial for protecting biological and environmental safety. However, the highly efficient and selective removal of heavy metal ions from multiple cations in wastewater is a significant challenge. This work proposed a pulse electrochemical method with a low-/high-voltage periodic appearance to selectively recover heavy metal ions from complex wastewater. It exhibited a higher recovery efficiency for heavy metal ions (100% for Pb2+ and Cd2+, >98% for Mn2+) than other alkali and alkaline earth metal ions (Na+, Ca2+, and Mg2+ were kept below 3.6, 1.3, and 2.6%, respectively) in the multicomponent solution. The energy consumption was only 34-77% of that of the direct current electrodeposition method. The results of characterization and experiment unveil the mechanism that the low-/high-voltage periodic appearance can significantly suppress the water-splitting reaction and break the mass-transfer limitation between heavy metal ions and electrodes. In addition, the plant study demonstrates the feasibility of treated wastewater for agricultural use, further proving the high sustainability of the method. Therefore, it provides new insights into the selective recovery of heavy metals from industrial wastewater.

Relationship between Copper, Zinc, and Copper-to-Zinc Ratio in Hair and Severity of Coronary Artery Disease according to the SYNTAX Score

Coronary artery disease (CAD) continues to be a foremost contributor to global mortality, and the quest for modifiable risk factors could improve prophylactic strategies. Recent studies suggest a significant role of zinc (Zn) and copper (Cu) deficiency in atheromatous plaque formation. Furthermore, hair was previously described as a valuable source of information on elemental burden during the 6-8 week period before sampling. The aim of this study was to investigate the possibility of correlation between the extent of CAD evaluated with the SYNergy Between PCI With TAXUS and the Cardiac Surgery (SYNTAX) score with Cu and Zn content in hair samples, as well as with the Cu/Zn ratio in a cohort of 130 patients. Our findings describe a statistically significant inverse correlation between Cu content and the Cu/Zn ratio in hair samples and the extent of CAD. In contrast, no significant correlation was found between Zn content and the extent of CAD. Considering the scarcity of existing data on the subject, the analysis of hair samples could yield a novel insight into elemental deficiencies and their potential influence on CAD extent.

Spatial distribution, impact factors, and potential health implications of trace elements in human hair from capital residents in China

We analyzed the levels, spatial distribution, impact factors, source apportionment, and potential health implications of trace elements (V, Zn, Cu, Mn, Ni, Mo, and Co) in 1202 human hair samples of urban residents aged 4-55 from 29 cities in China. The median values of seven trace elements in hair were found in the following increasing order: Co (0.02 μg/g) < V (0.04 μg/g) < Mo (0.05 μg/g) < Ni (0.32 μg/g) < Mn (0.74 μg/g) < Cu (9.63 μg/g) < Zn (157 μg/g). The spatial distribution of these trace elements in the hair from the six geographical subdivisions varied depending on the exposure sources and impact factors. Principal component analysis (PCA) revealed that Cu, Zn, and Co in the hair samples of urban residents were primarily derived from food, whereas V, Ni, and Mn were attributed to industrial activities and food. Majority of the hair samples (up to 81%) from North China (NC) exceeded the recommended value for V content, whereas up to 59.2%, 51.3%, and 31.6% samples from Northeast China (NE) exceeded the recommended values for Co, Mn, and Ni contents, respectively. The levels of Mn, Co, Ni, Cu, and Zn were significantly higher in female hair than those in male hair, whereas the levels of Mo were higher in male than in female hair (p < 0.01). Furthermore, significantly higher Cu/Zn ratios were observed in the hair of male residents than those in the female residents (p < 0.001), indicating a higher health risk for male residents.

Heavy metals in paired samples of hair and nails in China: occurrence, sources and health risk assessment

The occurrence of heavy metals including chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb) was investigated in paired samples of hair and nails collected from 121 volunteers in 16 cities, China. Results showed that the mean concentrations of Zn, Cu, As, Pb, Cr, Ni and Cd were 205, 18.0, 7.79, 6.18, 3.54, 2.02, 0.533 μg g^-1 in hair and 103, 8.09, 0.760, 7.27, 6.07, 8.81, 0.485 μg g^-1 in nails, respectively. The concentrations of Zn, Ni, Cr, Cd and Pb were positively correlated in paired samples of hair and nails, whereas a negative correlation was found for Cu and As between hair and nails. Higher concentrations of heavy metals were found in northern China than southern China. The multivariate analysis of variance revealed that dwelling environment was the dominant factor influencing the levels of Cd in hair (p < 0.05), while age was the dominant factor influencing the levels of Cr in nails (p < 0.05). Moreover, industrial pollution and smoking were also the important factors leading to the accumulation of heavy metals in human body. Principal component analysis (PCA) showed that industrial pollution and decoration material immersion were the main factors for the high concentrations of Cr and Ni in hair, accounting for 62.9% of the total variation; As in hair was dominantly related to groundwater pollution. The concentrations of heavy metals were within the recommended ranges in nails from this study. However, the mean levels of Cr, Ni and As in hair exceeded their recommended reference values, indicating potential health risks from heavy metals for residents in China.

Cerebrolysin Attenuates Exacerbation of Neuropathic Pain, Blood-spinal Cord Barrier Breakdown and Cord Pathology Following Chronic Intoxication of Engineered Ag, Cu or Al (50-60 nm) Nanoparticles

Neuropathic pain is associated with abnormal sensations and/or pain induced by non-painful stimuli, i.e., allodynia causing burning or cold sensation, pinching of pins and needles like feeling, numbness, aching or itching. However, no suitable therapy exists to treat these pain syndromes. Our laboratory explored novel potential therapeutic strategies using a suitable composition of neurotrophic factors and active peptide fragments-Cerebrolysin (Ever Neuro Pharma, Austria) in alleviating neuropathic pain induced spinal cord pathology in a rat model. Neuropathic pain was produced by constrictions of L-5 spinal sensory nerves for 2-10 weeks period. In one group of rats cerebrolysin (2.5 or 5 ml/kg, i.v.) was administered once daily after 2 weeks until sacrifice (4, 8 and 10 weeks). Ag, Cu and Al NPs (50 mg/kg, i.p.) were delivered once daily for 1 week. Pain assessment using mechanical (Von Frey) or thermal (Hot-Plate) nociceptive showed hyperalgesia from 2 weeks until 10 weeks progressively that was exacerbated following Ag, Cu and Al NPs intoxication in nerve lesioned groups. Leakage of Evans blue and radioiodine across the blood-spinal cord barrier (BSCB) is seen from 4 to 10 weeks in the rostral and caudal cord segments associated with edema formation and cell injury. Immunohistochemistry of albumin and GFAP exhibited a close parallelism with BSCB leakage that was aggravated by NPs following nerve lesion. Light microscopy using Nissl stain exhibited profound neuronal damages in the cord. Transmission electron microcopy (TEM) show myelin vesiculation and synaptic damages in the cord that were exacerbated following NPs intoxication. Using ELISA spinal tissue exhibited increased albumin, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP) and heat shock protein (HSP 72kD) upregulation together with cytokines TNF-α, IL-4, IL-6, IL-10 levels in nerve lesion that was exacerbated following NPs intoxication. Cerebrolysin treatment significantly reduced hyperalgesia and attenuated BSCB disruption, edema formation and cellular changes in nerve lesioned group. The levels of cytokines were also restored near normal levels with cerebrolysin treatment. Albumin, GFAP, MABP and HSP were also reduced in cerebrolysin treated group and thwarted neuronal damages, myelin vesiculation and cell injuries. These neuroprotective effects of cerebrolysin with higher doses were also effective in nerve lesioned rats with NPs intoxication. These observations suggest that cerebrolysin actively protects spinal cord pathology and hyperalgesia following nerve lesion and its exacerbation with metal NPs, not reported earlier.

Survey to identify the metal accumulation pathway in humans using hair and nail as biomarkers from fisherfolk population

Human hair and nail samples from Cuddalore fisherfolk populations were used as biomarkers for assessing metal concentrations in humans. Hair samples from 80 participants (47 men and 33 women) and nail samples from 40 participants (21 men and 19 women) were collected, and the concentrations of Cd, Cu, Pb, and Zn were assessed using an atomic absorption spectrophotometer (AAS). Metal data from AAS were compared with the survey questionnaire's personal and dietary parameters. Results indicate that both personal and dietary parameters may influence metal exposure; however, majority of the sources may have originated from metal-contaminated seafood. Higher metal accumulation in communities, especially those which consume seafood on a daily basis, may increase the possibility for them to get affected by metal-related diseases. Based on environmental parameters, people who live ≤500 m from industrial zones accumulate more metals. Further extensive studies with more individuals and more questionnaire parameters are needed to identify the metal accumulation pathway in humans.

Potentially toxic elements in human scalp hair around China's largest polymetallic rare earth ore mining and smelting area

There is a growing concern about human health of residents living in areas where mining and smelting occur. In order to understand the exposure to the potentially toxic elements (PTEs), we here identify and examine the cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in scalp hair of residents living in the mining area (Bayan Obo, n = 76), smelting area (Baotou, n = 57) and a reference area (Hohhot, n = 61). In total, 194 hair samples were collected from the volunteers (men = 87, women = 107) aged 5-77 years old in the three areas. Comparing median PTEs levels between the young and adults, Ni levels were significantly higher in adults living in the smelting area while Cr was highest in adults from the mining area, no significant difference was found for any of the elements in the reference area. From the linear regression model, no significant relationship between PTEs concentration, log₁₀(PTEs), and age was found. The concentrations of Ni, Cd, and Pb in hair were significantly lower in the reference area when compared to both mining and smelting areas. In addition, Cu was significantly higher in the mining area when compared to the smelting area. Factor analysis (FA) indicated that men and women from the smelting area (Baotou) and mining area (Bayan Obo), respectively, had different underlying communality of log10(PTEs), suggesting different sources of these PTEs. Multiple factor analysis quantilized the importance of gender and location when combined with PTEs levels in human hair. The results of this study indicate that people living in mining and/or smelting areas have significantly higher PTEs (Cu, Ni, Cd, and Pb) hair levels compared to reference areas, which may cause adverse health effects. Remediation should therefore be implemented to improve the health of local residents in the mining and smelting areas.

Ionomics-metabolome association analysis as a new approach to the impact of dietary copper levels in suckling piglets model

Ionomics-metabolomics association analysis is a novel method to elucidating the potential mechanisms underlying the effects of dietary copper on the overall health parameters of suckling piglets model. Few studies have elucidated the relationship between the changes of ionic and metabolic homeostasis responses to dietary copper level. The growth performance data was obtained from 180 suckling piglets which access to different copper levels: 6 (low copper diet, LC), 20 (control diet, CON), and 300 (high copper diet, HC) mg·kg^-1 copper (based on diet, supplementation from CuSO₄), and offered ad libitum from d 14 until weaning at 40 d of age. Dietary high level copper (300 mg·kg^-1) increased the ADG and ADFI during d 14 to 28 of piglets. Six elements (Mg, Na, K, P, Cu, and Mn) concentrations significantly changes in hair among the three treatment diets. The significant increased concentrations of Na and K, and decreased concentration of Mg and Mn in 300 mg·kg^-1 than 20 mg·kg^-1 copper diet was observed. In current study, with the increase in copper level from 20 to 300 mg·kg^-1 in diet, the correlation between hair Na, K and Cu, Mn, Zn vanish. Hair Na and K were positively correlated with serum total antioxidant capacity (T-AOC) and negatively correlated with tumor necrosis factor-α (TNF-α). The hair Cu was negatively correlated with serum malondialdehyde (MDA), total bile acid (TBA). The fecal Cu was positively correlated with serum growth hormone (GH). The results suggested that the average daily gain (ADG) in 6 mg·kg^-1 copper diet and the average daily feed intake (ADFI) in 20 mg·kg^-1 copper diet were decreased than 300 mg·kg^-1 copper diet during d 14 to 28 and the ADG was decreased in 6 and 20 mg·kg^-1 copper diets in d 29 to 40 of piglets. Dietary 20 mg·kg^-1 copper maintain ion homeostasis due to increase the number of positive correlations between macroelements-microelements in hair and serum. Significantly changed Na, K, Mg, Mn and Cu concentrations in hair can reflect the adverse effects of dietary 300 mg·kg^-1 copper of suckling piglets. We believe our results may benefit people to gain a better understanding of the ion interactions and metabolic homeostasis of heavy metal elements that are critical to human and animal health.

Recent advances in the application of ionomics in metabolic diseases

Trace elements and minerals play a significant role in human health and diseases. In recent years, ionomics has been rapidly and widely applied to explore the distribution, regulation, and crosstalk of different elements in various physiological and pathological processes. On the basis of multi-elemental analytical techniques and bioinformatics methods, it is possible to elucidate the relationship between the metabolism and homeostasis of diverse elements and common diseases. The current review aims to provide an overview of recent advances in the application of ionomics in metabolic disease research. We mainly focuses on the studies about ionomic or multi-elemental profiling of different biological samples for several major types of metabolic diseases, such as diabetes mellitus, obesity, and metabolic syndrome, which reveal distinct and dynamic patterns of ion contents and their potential benefits in the detection and prognosis of these illnesses. Accumulation of copper, selenium, and environmental toxic metals as well as deficiency of zinc and magnesium appear to be the most significant risk factors for the majority of metabolic diseases, suggesting that imbalance of these elements may be involved in the pathogenesis of these diseases. Moreover, each type of metabolic diseases has shown a relatively unique distribution of ions in biofluids and hair/nails from patients, which might serve as potential indicators for the respective disease. Overall, ionomics not only improves our understanding of the association between elemental dyshomeostasis and the development of metabolic disease but also assists in the identification of new potential diagnostic and prognostic markers in translational medicine.

Potentially toxic elements exposure biomonitoring in the elderly around the largest polymetallic rare earth ore mining and smelting area in China

Potentially toxic elements (PTEs) can be released during mining operations and ore processing. The pollution and health risk related to PTEs in total suspended particulates (TSPs) around the largest polymetallic rare earth mining area (Bayan Obo) and smelting area (Baotou) in Inner Mongolia, China, were evaluated. PTEs in the hair of the elderly living in these two areas and a reference area (Hohhot) were also examined. Relationships between PTEs in TSPs and hair with categorical factors (location, gender, etc.) were also modeled. Multivariate statistical analyses were carried out to analyze the possible sources of the PTEs in TSPs. The bubble maps of the concentrations of PTEs indicated that high concentrations of PTEs were near the industrial area where smelting plants and power plants were located. In addition, health risks were assessed for adults in the mining and smelting area. The carcinogenic risk of Cr was high for residents in the study areas. Also, the residents were exposed to a non-carcinogenic risk of Ni. Significant mean value differences were observed between PTEs in the hair of the elderly in Baotou and Hohhot. Results of the linear regression model indicated that around 31 % of the Pb in hair could be explained by the linear regression model, it could be affected by Ni and Zn in TSPs, but location, gender, and sampling time showed no significant contribution. Age was not significantly associated with the PTEs levels in hair in Baotou and Bayan Obo. The results provide important scientific evidence for a better understanding of the effects of PTEs in TSPs in polymetallic ore mining and smelting areas.

Short- and long-term exposure to trace metal(loid)s from the production of ferromanganese alloys by personal sampling and biomarkers

The environmental exposure to trace metal(loid)s (As, Cd, Cu, Fe, Mn, Pb, and Zn) was assessed near a ferromanganese alloy plant using filters from personal particulate matter (PM) samplers (bioaccessible and non-bioaccessible fine and coarse fractions) and whole blood as short-term exposure markers, and scalp hair and fingernails as long-term biomarkers, collected from volunteers (n = 130) living in Santander Bay (northern Spain). Bioaccessible and non-bioaccessible metal(loid) concentrations in coarse and fine PM from personal samplers were determined by ICP-MS after extraction/digestion. Metal(loid) concentration in biomarkers was measured after alkaline dilution (whole blood) and acid digestion (fingernails and scalp hair) by ICP-MS as well. Results were discussed in terms of exposure, considering the distance to the main Mn source, and sex. In terms of exposure, significant differences were found for Mn in all the studied fractions of PM, As in whole blood, Mn and Cu in scalp hair and Mn and Pb in fingernails, with all concentrations being higher for those living closer to the Mn source, with the exception of Cu in scalp hair. Furthermore, the analysis of the correlation between Mn levels in the studied biomarkers and the wind-weighted distance to the main source of Mn allows us to conclude that scalp hair and mainly fingernails are appropriate biomarkers of long-term airborne Mn exposure. This was also confirmed by the significant positive correlations between scalp hair Mn and bioaccessible Mn in coarse and fine fractions, and between fingernails Mn and all PM fractions. This implies that people living closer to a ferromanganese alloy plant are exposed to higher levels of airborne metal(loid)s, mainly Mn, leading to higher levels of this metal in scalp hair and fingernails, which according to the literature, might affect some neurological outcomes. According to sex, significant differences were observed for Fe, Cu and Pb in whole blood, with higher concentrations of Fe and Pb in males, and higher levels of Cu in females; and for Mn, Cu, Zn, Cd and Pb in scalp hair, with higher concentrations in males for all metal(loid)s except Cu.

High manganese and nickel concentrations in human hair and well water and low calcium concentration in blood serum in a pristine area with sulphide-rich bedrock

We report the trace element status of residents living in areas with naturally sulphide-rich bedrock and soil in two municipalities in Finland, Sotkamo and Kaavi. Altogether, 225 people from these sparsely populated regions participated voluntarily by providing hair and blood samples. The concentrations of calcium, zinc and copper in serum as well as selenium and cadmium in whole blood did not show correlation with those concentrations in hair samples. Calcium concentration in serum was slightly lower in the sulphide-rich areas (median value 91.4 mg/l, n = 103) than in the areas with adjacent sulphur-poor bedrock (median value 93.6 mg/l, n = 82). The concentrations of Ni and Mn in hair correlated with those in drinking water. The highest Mn and Ni concentrations in the water samples from private wells were 1620 µg/l and 51 µg/l and the highest concentrations in human hair samples 36.44 mg/kg and 12.3 mg/kg, respectively. The challenge with elevated trace element concentrations in some well waters is well documented. In northern countries (Finland, Sweden, Norway and Canada), only 10% of the population depend on private well water, and 90% have access to monitored municipal water supplies. Compared with data available from sulphide mine sites globally, the nickel and manganese concentrations in human hair samples were high in our sulphide-rich study area at Sotkamo representing the trace element status of residents under natural conditions.

Investigation on the Association of Copper and Copper-to-Zinc-Ratio in Hair with Acute Coronary Syndrome Occurrence and Its Risk Factors

The prevalence of coronary artery disease (CAD) increases every year; however, the impact of microelements on its underlying cause—atherosclerosis—is still unclear. Copper plays numerous regulatory roles in cardiovascular health and was suggested to influence the classic risk factors for CAD. The copper-to-zinc-ratio (Cu/Zn-ratio) reflects systemic oxidative stress–one of the factors in the complex pathogenesis of atherosclerosis. Hair incorporates metal ions during its growth; thus, it reflects the metal exposure that occurred over the last 4–8 weeks. The aim of the presented study was to verify the association between Cu and Cu/Zn-ratio content and the occurrence of acute coronary syndrome (ACS) in the hair of 133 patients who underwent coronary angiography due to suspected ACS. Additionally, association between Cu and Cu/Zn-ratio and selected risk factors for CAD was analyzed. Neither Cu nor Cu/Zn-ratio levels were associated with the occurrence of ACS, regardless of its type (UA/NSTEMI/STEMI). We did not find a significant association between Cu content in hair and risk factors for CAD. The Cu/Zn-ratio in hair was significantly correlated only with body mass index. The relationship of Cu content and Cu/Zn-ratio in hair with CAD, its risk factors and ACS appears to be complex and requires further well-designed research.

Widespread nickel contamination in drinking water supplies of elementary schools in Taichung, Taiwan

Owing to the limited information regarding potential sources of nickel (Ni) in drinking water, incidences of Ni contamination have not been well elucidated in the literature. However, in recent decades, Ni-containing plumbing materials such as stainless steel pipes, brass fittings, and chrome faucets have gained popularity in drinking water distribution systems. As a result of increased use of such materials, Ni levels in drinking water are expected to rise over time, posing long-term exposure risks to consumers. For the first time, this study employed an intensive sequential sampling, from October 2019 to July 2020, to assess Ni levels in drinking water samples collected from dispensers of elementary schools in Taichung, Taiwan. Of the total 580 sequential samples collected from 58 elementary schools, 45 samples from 17 schools exceeded the Taiwan Environmental Protection Administration (EPA) standard value of 20 μg/L for Ni. Total Ni concentration in 1 L sample, an average of the total Ni concentrations in 10 sequential samples, exceeded in 4 schools. This finding suggests minor Ni contamination in drinking water supplies across the city. The highest Ni concentration was measured in the 1st sequential sample reaching 154 μg/L. Weekend and summer samples exhibited a higher tendency to exceed the standard. Older schools with age above 50 years and schools with a higher student population (≥ 500) were more likely to have Ni contamination. This study showed that drinking water is a potential source of Ni. However, the identification of Ni source, whether within the dispenser or in the distribution system, warrants further research.

Heavy Metal in Rice and Vegetable and Human Exposure near a Large Pb/Zn Smelter in Central China

Non-ferrous metal smelting is a significant source of anthropogenic heavy metal emission and has led to severe environmental pollution that ultimately threatens the health of local residents. In this study, we determined concentrations of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb), as well as Pb isotopic compositions in rice, vegetables and human hair in areas surrounding the Zhuzhou Pb/Zn smelter in Hunan, China and we assessed the health risks associated with rice and vegetable consumption for local residents. Results showed that rice and vegetable samples were significantly contaminated by Cd and Pb. Age and source of rice were important factors for the enrichment of heavy metal concentrations in human hair. The ratios of Pb isotopes in human hair (1.164-1.170 for ²⁰⁶Pb/²⁰⁷Pb and 2.102-2.110 for²⁰⁸Pb/²⁰⁶Pb) were comparable to those in rice (1.162-1.172 for ²⁰⁶Pb/²⁰⁷Pb and 2.098-2.114 for²⁰⁸Pb/²⁰⁶Pb) and were slightly lower than those in vegetables (1.168-1.172 for ²⁰⁶Pb/²⁰⁷Pb and 2.109-2.111 for²⁰⁸Pb/²⁰⁶Pb), indicating that Pb in human hair mainly originated from food ingestion. A non-carcinogenic risk assessment showed that Cd exposure was the dominant health risk for local residents. This study suggested that crops planted surrounding the smelter were seriously contaminated with Cd and human exposure was related to dietary intake.

Crop uptake of heavy metals in response to the environment and agronomic practices on land near mine tailings in the Zambian Copperbelt Province

A field experiment was undertaken on farmers' fields adjacent to a large mine tailings dam in the Zambian mining town of Kitwe. Experimental plots were located close to the tailings (≤ 200 m) or further away (300-400 m) within the demarcated land farmed by the same community. This study evaluated the uptake of Cd, Cu, Ni, Pb and Zn by pumpkin leaves and maize grown in soil amended with lime and manure applied at agronomic rates, and the subsequent risk of dietary exposure to the local community, typical of many similar situations across the Zambian Copperbelt. Treatments, combinations of lime and manure (present or absent), were applied to subplots selected independently and randomly within each main plot, which represented variable geochemistry across this study site as a result of windblown/rain-driven dust from the tailings. Total elemental concentrations in crops were determined by ICP-MS following microwave-assisted acid digestion. Concentrations of Cu and Pb in pumpkin leaves were above the prescribed FAO/WHO safe limits by 60-205% and by 33-133%, respectively, while all five metals were below the limit for maize grain. Concentration of metals in maize grain was not affected by the amendments. However, lime at typical agronomic application rates significantly reduced concentrations of Cd, Cu, Pb and Zn in the pumpkin leaves by 40%, 33%, 19% and 10%, respectively, and for manure Cd reduced by 16%, while Zn increased by 35%. The uptake of metals by crops in locations further from the tailings was greater than closer to the tailings because of greater retention of metals in the soil at higher soil pH closer to the tailings. Crops in season 2 had greater concentrations of Cu, Ni, Pb and Zn than in season 1 due to diminished lime applied only in season 1, in line with common applications on a biannual basis. Maize as the staple crop is safe to grow in this area while pumpkin leaves as a readily available commonly consumed leafy vegetable may present a hazard due to accumulation of Cu and Pb above recommended safe limits.

Hair mineral analysis in the population of students living in the Lower Silesia region (Poland) in 2019: Comparison with biomonitoring study in 2009 and literature data

The paper presents a comparative analysis of biomonitoring research results using hair mineral analysis today and 10 years ago. The aim of the present work was to examine the impact of individual factors, on the content of elements in human hair. The mineral analysis of 115 hair samples was carried out using ICP-OES and AAS technique. It was shown that calcium, barium, copper, mercury, magnesium, manganese and selenium content depend on gender and is higher for women. Statistically significant synergistic correlations were identified between the following pairs of elements: (Ca-Mg), (P-S), (Mo-Sb) and (Ba-Pb). The results of the present work were compared with the previous assessment in 2009 on students of the same age. The content of most of the heavy metals in hair was reduced significantly, which is a sign of the improving state of the local environment. The greatest decrease was recorded for silver (96.6%), arsenic (93.4%), mercury (45.1%), lead (67.7%), antimony (55.2%), thallium (10 times) and cobalt (93.7%). The level of the following elements increased: Ba: 27.3%, Cu: 28.5%, Ni: 22.4%, Ti: 191%, Zn: 11.0%. Changes in the content of most heavy metals in hair have been noted, as well as changes of reference ranges, which may indicate an improvement in the state of the environment in Wrocław, Lower Silesia (Poland) over the last 10 years. These results were confirmed by biomonitoring studies carried out with human hair, which was shown to be a reliable biomarker of human exposure to toxic elements.

Manganese in the Diet: Bioaccessibility, Adequate Intake, and Neurotoxicological Effects

Manganese (Mn) is an essential element that participates in several biological processes. Mn serves as a cofactor for several enzymes, such as glutamine synthetase and oxidoreductases, that have an important role in the defense of the organisms against oxidative stress. The diet is the main source of Mn intake for humans, and adequate daily intake levels for this metal change with age. Moreover, in higher amounts, Mn may be toxic, mainly to the brain. Here, we provide an overview of Mn occurrence in food, addressing its bioaccessibility and discussing the dietary standard and recommended intake of Mn consumption. In addition, we review some mechanisms underlying Mn-induced neurotoxicity.

Do soil amendments used to improve agricultural productivity have consequences for soils contaminated with heavy metals?

This study presents an analysis of the effects of manure and lime commonly used to improve agricultural productivity and evaluates the potential for such soil amendments to mobilise/immobilise metal fractions in soils contaminated from nearby mine tailings in the Zambian Copperbelt. Lime and manure were applied at the onset of the study, and their effects were studied over two planting seasons, i.e. 2016-17 and 2017–18. Operationally defined plant-available Cd, Cu, Ni, Pb and Zn in the soil, were determined by extraction with DTPA-TEA (diethylenetriaminepentaacetic acid-triethanolamine) and 0.01 M Ca(NO₃)₂, before, and after, applying the amendments. In unamended soils, Cd was the most available and Ni the least. Lime application decreased extractable Cd, Cu, Ni, Pb and Zn. The response to lime was greater in soils with an initially acidic pH than in those with approximately neutral pH values. Manure increased DTPA extractable Zn, but decreased DTPA and Ca(NO₃)₂ extractable Cd, Cu and Pb. Combined lime and manure amendment exhibited a greater reduction in DTPA extractable Cd, Ni, Pb, Zn, as well as for Ca(NO₃)₂ extractable Cd compared to separate applications of lime and manure. The amendments had a significant residual effect on most of the soil fractions between season 1 and 2. The results obtained in this study showed that soil amendment with minimal lime and manure whilst benefiting agricultural productivity, may significantly reduce the mobility or plant availability of metals from contaminated agricultural soils. This is important in contaminated, typical tropical soils used for crop production by resource poor communities affected by mining or other industrial activities.

Disease Ionomics: Understanding the Role of Ions in Complex Disease

Ionomics is a novel multidisciplinary field that uses advanced techniques to investigate the composition and distribution of all minerals and trace elements in a living organism and their variations under diverse physiological and pathological conditions. It involves both high-throughput elemental profiling technologies and bioinformatic methods, providing opportunities to study the molecular mechanism underlying the metabolism, homeostasis, and cross-talk of these elements. While much effort has been made in exploring the ionomic traits relating to plant physiology and nutrition, the use of ionomics in the research of serious diseases is still in progress. In recent years, a number of ionomic studies have been carried out for a variety of complex diseases, which offer theoretical and practical insights into the etiology, early diagnosis, prognosis, and therapy of them. This review aims to give an overview of recent applications of ionomics in the study of complex diseases and discuss the latest advances and future trends in this area. Overall, disease ionomics may provide substantial information for systematic understanding of the properties of the elements and the dynamic network of elements involved in the onset and development of diseases.

Reconnaissance sampling and determination of hexavalent chromium in potentially-contaminated agricultural soils in Copperbelt Province, Zambia

The distribution of elemental species of chromium (Cr) in potentially-contaminated soil samples warrants investigation due to the differing mobilities and toxicities of trivalent [Cr(III)] and hexavalent chromium [(Cr(VI)]. In addition, the possibility of species interconversions requires the implementation of robust methods that can correct for changes at the point of sampling, extraction and analysis. This work presents the application of speciated isotope dilution mass spectrometry (SIDMS) to accurately quantify Cr(VI) in agricultural soils within close proximity to a mine tailings dam in the Copperbelt Province of Zambia. Interpolated plots of total Cr, produced from data collected through a nested sampling design, were used to optimise the sampling across the spatial domain. Extraction of Cr(VI) was undertaken using a microwave assisted reaction system (80 °C for 5 min) with 50 mM EDTA, to complex Cr(III) and reduce the likelihood of oxidation during the extraction. Isotopically-enriched ⁵³Cr(VI) was added to each sample prior to extraction to account for species interconversions. The accuracy of the method was confirmed using NIST SRM 2700 and 2701. Cr(VI) concentrations in the soil samples ranged between 0.03 and 0.29 mg kg^-1, significantly lower than the residential UK screening value for Cr(VI) of 21 mg kg^-1. The data indicate that this site poses a low environmental/human health risk with respect to Cr(VI) exposure.

Prepubertal overexposure to manganese induce precocious puberty through GABAA receptor/nitric oxide pathway in immature female rats

Gamma-aminobutyric acid (GABA) plays a critical role in regulation of gonadotropin-releasing hormone (GnRH) through GABA_A receptor (GABA_AR). Nitric oxide (NO) production has correlation with GABA and regulates GnRH secretion. This study was performed to examine the mechanisms by which manganese (Mn) accelerate puberty onset involves GABA_AR/NO pathway in the preoptic area-anterior hypothalamus (POA-AH) in immature female rats. First, female rats received daily dose of MnCl₂ 0 (saline), 2.5, 5 and 10 mg/kg b.w by oral gavage during postnatal day (PND) 21-32. Animals administered with 10 mg/kg MnCl₂ exhibited earlier puberty onset age and advanced ovary and uterus development than these in saline-treatment group. Furthermore, we found that decrease of GABA_AR result in elevated production of nitric oxide synthase1 (NOS1), NO and GnRH in the POA-AH. Second, we recorded the neuronal spikes alternation after perfusion with GABA_AR inhibitor bicuculline (BIC), GABA_AR agonist isoguvacine (isog), and MnCl₂ from the POA-AH in acute brain slices of PND21 rats. Spontaneous firing revealed a powerful GABA_AR-mediated action on immature POA-AH and confirm that MnCl₂ has a significant effect on GABA_AR. Third, we revealed that decrease in NOS1 and NO production by treatment with isog-alone or isog+MnCl₂ contribute to the decrease of GnRH in the POA-AH and a delayed puberty onset age compared to treatment with MnCl₂-alone. Together, these results suggested that excessive exposure to MnCl₂ stimulates NO production through decreased GABA_AR in the POA-AH to advance puberty onset in immature female rats.

Gap analysis of nickel bioaccessibility and bioavailability in different food matrices and its impact on the nickel exposure assessment

The metal nickel is well known to cause nickel allergy in sensitive humans by prolonged dermal contact to materials releasing (high) amounts of nickel. Oral nickel exposure via water and food intake is of potential concern. Nickel is essential to plants and animals and can be naturally found in food products or contamination may occur across the agro-food chain. This gap analysis is an evaluation of nickel as a potential food safety hazard causing a risk for human health. In the first step, the available data regarding the occurrence of nickel and its contamination in food and drinks have been collected through literature review. Subsequently, a discussion is held on the potential risks associated with this contamination. Elevated nickel concentrations were mostly found in plant-based foods, e.g. legumes and nuts in which nickel of natural origin is expected. However, it was observed that dedicated and systematic screening of foodstuffs for the presence of nickel is currently still lacking. In a next step, published studies on exposure of humans to nickel via foods and drinks were critically evaluated. Not including bioaccessibility and/or bioavailability of the metal may lead to an overestimation of the exposure of the body to nickel via food and drinks. This overestimation may be problematic when the measured nickel level in foods is high and bioaccessibility and/or bioavailability of nickel in these products is low. Therefore, this paper analyzes the outcomes of the existing dietary intake and bioaccessibility/bioavailability studies conducted for nickel. Besides, the available gaps in nickel bioaccessibility and/or bioavailability studies have been clarified in this paper. The reported bioaccessibility and bioavailability percentages for different food and drinks were found to vary between <LOD and 83% and between 0 and 30% respectively. This indicates that of the total nickel contained in the foodstuffs only a fraction can be absorbed by the intestinal epithelium cells. This paper provides a unique critical overview on nickel in the human diet starting from factors affecting its occurrence in food until its absorption by the body.