Daily intake of manganese by the adult population of Mumbai

Impact of Gd3+ doping on structural, electronic, magnetic, and photocatalytic properties of MnFe2O4 nanoferrites and application in dye-polluted wastewater remediation

The present work focuses on developing Gd-doped Mn spinel nanoferrites and their potential application in the photodegradation of water pollutants. The impact of Gd³⁺ ion substitution on structural, electronic, and magnetic characteristics of manganese ferrites has been studied. Nanocrystalline samples of MnGd_xFe_2-xO₄ (x = 0.0 to 0.10, in step size of 0.02) ferrites were prepared via sol-gel self-ignition route. The Rietveld, XPS, HRTEM, and SAED characterization methods confirmed the formation of phase pure ferrite nanoparticles (~ 8-22 nm) in the cubic spinel structure. The Gd³⁺ content in these nanoferrites responded to a systematic reduction in the size of nanocrystallites and an upsurge in the density of nanoferrites. The XPS study revealed fine assimilation of constituent elements in the fcc lattice and ruled out impurities in the nanoferrites. The Fe and the Gd ions were found to be in Fe³⁺ and Gd³⁺ states, respectively. While a major fraction of the Mn ions were found to be in the Mn²⁺ state, a small fraction of Mn⁴⁺ ions was observed on the surface of nanoparticles. The nanoferrites were found to exhibit a soft ferromagnetic state from 300 to 20 K limits. The highest saturation magnetization was observed for x = 0.02 (M_S = 66.6 emu/g at 20 K). The observed magnetic properties can be understood with the competing (Fe³⁺ and Mn²⁺)_A-O^2--[Fe³⁺, Mn²⁺, and Gd³⁺]_B superexchange interactions and magnetocrystalline anisotropy. Due to the small band gap energy of Gd-doped Mn ferrites than that of the pure Mn ferrite, they have demonstrated excellent photocatalytic activity for the degradation of methylene blue (MB) dye under visible light illumination. As much as 96.35% of the MB dye was found to get degraded in 70 min of light illumination over synthesized nanoparticles and the photodegradation reaction followed pseudo-first-order kinetics. The increased optical absorbance due to lower band gap, suppressed recombination rate of charge carriers, and enhanced charge mobility make them effective visible light active photocatalysts. This study revealed that the electronic, optical, and magnetic properties of MnFe₂O₄ nanoferrites could be easily tuned by varying the Gd³⁺ content and the prepared Gd-doped MnFe₂O₄ nanomaterials have boundless potential to be utilized in the future making promising active photocatalysts and degradation of harmful industrial dyes for enhanced protection in the fields of environment and health care.

Snack foods and lead ingestion risks for school aged children: A comparative evaluation of potentially toxic metals and children's exposure response of blood lead, copper and zinc levels

Snack foods are common and highly advertised to children and serve their natural predispositions for sweet and salty tastes. However, the risk issues of low-cost snacks eaten by 0-6 aged children are lack of more concern. To better understand the issue of low-cost snacks this study considered potentially toxic metals (PTMs) impact on children's health risk, measured PTMs in a collection of 570 collected low-cost snacks contributed by 1342 voluntary participants children aged 0-6 years involved in Xi'an city are conducted. Nine priority PTMs and amounts ranked as Mn > Zn > Cu > Cr > Sb > Pb > Ni > Cd > Co. The Estimated Weekly Intake of PTMs in snacks for children accounted for a proportion of the Provisional Tolerance Weekly Intake. Children's daily snack ingestion of Cr, Cd and Pb were especially concerning. It was noted that all PTMs in flour products contribute to the total Target Hazard Quotient (THQ>1) were observed having a non-carcinogenic risk compared to the single metals Cr, Co and Cd with carcinogenic risk. The correlations between Cu, Pb, Zn in low-cost snacks and children's bloods reflected PTMs especially for Pb that transfers into children's bodies mostly through low-cost foodstuffs ingestion. Also, the elevated blood lead levels (BLLs) depended on readily available, low-quality snacks accessible for children. Therefore, multi-initiatives aimed at improving the quality, increasing awareness, and a PTM monitoring program for low-cost snack food market to young children should be undertaken.

Manganese Ferrite Nanoparticles (MnFe2O4): Size Dependence for Hyperthermia and Negative/Positive Contrast Enhancement in MRI

We synthesized manganese ferrite (MnFe₂O₄) nanoparticles of different sizes by varying pH during chemical co-precipitation procedure and modified their surfaces with polysaccharide chitosan (CS) to investigate characteristics of hyperthermia and magnetic resonance imaging (MRI). Structural features were analyzed by X-ray diffraction (XRD), high-resolution transmission electron microscopy (TEM), selected area diffraction (SAED) patterns, and Mössbauer spectroscopy to confirm the formation of superparamagnetic MnFe₂O₄ nanoparticles with a size range of 5–15 nm for pH of 9–12. The hydrodynamic sizes of nanoparticles were less than 250 nm with a polydispersity index of 0.3, whereas the zeta potentials were higher than 30 mV to ensure electrostatic repulsion for stable colloidal suspension. MRI properties at 7T demonstrated that transverse relaxation (T₂) doubled as the size of CS-coated MnFe₂O₄ nanoparticles tripled in vitro. However, longitudinal relaxation (T₁) was strongest for the smallest CS-coated MnFe₂O₄ nanoparticles, as revealed by in vivo positive contrast MRI angiography. Cytotoxicity assay on HeLa cells showed CS-coated MnFe₂O₄ nanoparticles is viable regardless of ambient pH, whereas hyperthermia studies revealed that both the maximum temperature and specific loss power obtained by alternating magnetic field exposure depended on nanoparticle size and concentration. Overall, these results reveal the exciting potential of CS-coated MnFe₂O₄ nanoparticles in MRI and hyperthermia studies for biomedical research.

Dietary Intake and Urinary Excretion of Manganese in Korean Healthy Adults

Manganese (Mn) is an essential element for the body's composition and is required for various functions, including nutrient metabolism, immune system function, and antioxidant ability. However, there are insufficient data on the nutritional status of Mn. In this study, we aimed to analyze the relationship between Mn intake and urinary excretion in Korean adults. A twice dietary intake survey using a 24-h recall method was conducted on 640 adults (320 men and 320 women), aged 20 to 69 years. Eighty 24-h urine samples were also twice collected and urinary Mn excretions were analyzed. Results indicated that total Mn intake per day was 4.1 mg for men and 3.9 mg for women (p < 0.05). Mn intake per 1000 kcal of energy consumption was significantly higher in women than in men (2.0 mg/1,000 kcal vs. 2.2 mg/1000 kcal, p < 0.01). Additionally, Mn intake as a percentage of Adequate Intake was 103.0% for men and 110.3% for women (p < 0.05). Mn was mostly consumed from cereals (1.78 mg/day for men and 1.53 mg/day for women), followed by vegetables, seasonings, fruits, and pulses. The main food sources of Mn were rice (27.8% for men, 22.0% for women), kimchi (3.5% for men, 1.4% for women), and tofu (2.8% for men, 2.3% for women); the percentage of Mn consumed from 20 types of foods was 55.6% (women) to 60.4% (men). Urinary Mn excretion was negatively correlated with Mn intake from cereals and positively with mushrooms only for women after adjusting for confounding factors (p < 0.05). In conclusion, dietary Mn intake by Korean adults was adequate to meet the Dietary Reference Intake, but the relationship between Mn intake and urinary excretion was not clear.

Implementation of Dietary Reference Intake Standards in Prison Menus in Poland

Adequate nutrition in prisons should constantly be monitored due to the limited possibilities of external control as well as the low catering budget for prison meals and poorly defined requirements in this regard. The aim of the study was to assess the nutritional value of meals served in Polish prisons. Using a computer program, 14-day regular and bland diets from 30 prisons were analyzed. The energy value of the meals and the percentage of energy provided by protein, fat, and carbohydrate contained therein were found to meet the recommendations of the Polish National Food and Nutrition Institute. The amount of minerals supplied with the diet did not cover the recommended dietary allowance (RDA) in the case of calcium and magnesium. Particularly disturbing was the excessive supply of sodium in the regular and bland diets, which covered 537% and 311% of the dietary reference intake (DRI), respectively, as well as phosphorus (194 and 192% of RDA). The largest vitamin deficiencies were recorded for vitamins D and C and folate. An especially excessive supply was observed for vitamins A and B₁₂. The type of diet significantly differentiated the average content of over half of the analyzed components, whereas the season of the year turned out to be statistically insignificant. The results of the present investigations indicate a need for development of more accurate legal provisions to regulate the nutrition in Polish prisons in terms of not only the energy value and macronutrient supply but also the intake of minerals and vitamins.

Dietary intake of manganese and the risk of the metabolic syndrome in a Chinese population

Animal studies have suggested that Mn might be associated with some components of the metabolic syndrome (MetS). A few epidemiological studies have assessed dietary Mn intake and its association with the risk of the MetS and its components among Chinese adults. In this study, we assessed daily dietary Mn intake and its relationship with MetS risk among Chinese adults in Zhejiang Province using data from the 5th Chinese National Nutrition and Health Survey (2010–2012). A total of 2111 adults were included. Dietary Mn intake was assessed using 3-d 24-h dietary recalls; health-related data were obtained by questionnaire surveys, physical examinations and laboratory assessments. The mean intake of Mn was 6·07 (sd 2·94) mg/d for men (n 998) and 5·13 (sd 2·65) mg/d for women (n 1113). Rice (>42 %) was the main food source of Mn. The prevalence of the MetS was 28·0 % (590/2111). Higher Mn intake was associated with a decreased risk of the MetS in men (Q4 v. Q1 OR 0·62; 95 % CI 0·42, 0·92; P_trend=0·043) but an increased risk in women (Q4 v. Q1 OR 1·56; 95 % CI 1·02, 2·45; P_trend=0·078). In addition, Mn intake was inversely associated with abdominal obesity (P_trend=0·016) and hypertriacylglycerolaemia (P_trend=0·029) in men, but positively associated with low HDL-cholesterol in both men (P_trend=0·003) and women (P_trend<0·001). Our results suggest that higher Mn intakes may be protective against the MetS in men. The inverse association between Mn intake and the MetS in women might be due to the increased risk for low HDL-cholesterol.

Radiation dose to members of public residing around uranium mining complex, Jaduguda, Jharkhand, India

Uranium mining activities in the Jaduguda region of Jharkhand state, India have been carried out for the last five decades. Radioactive releases from mines, ore processing facility and tailings pond may increase the natural radiation dose to members of the public residing around the complex. It is, therefore, imperative to investigate the radiological condition around the uranium mining complex and assess the dose received by them. In the present study, it was estimated that the average radiation dose from all exposure pathways to the public living in villages around the mining complex is 2.5 mSv y(-1) and around 50 % contributed due to inhalation of radon and its progeny. The external radiation dose due to terrestrial and cosmic activity is estimated to be 1.1 mSv y(-1), which is 40 % of the total dose and ingestion dose contributes only 3% to the total dose.

Betel quid chewing as a source of manganese exposure: total daily intake of manganese in a Bangladeshi population

BACKGROUND

A relationship between betel quid chewing in Bangladeshi populations and the development of skin lesions and tremor has been previously reported, for people exposed to high levels of arsenic (As) through drinking contaminated groundwater. Exposure to manganese (Mn) is also known to induce neurotoxicity and levels of Mn in Bangladeshi groundwater are also high. The present study evaluates betel quid chewing as an overlooked source of Mn exposure in a Bangladeshi population.

METHODS

Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine (1) urinary Mn levels for 15 chewers and 22 non-chewers from the ethnic Bangladeshi community in the United Kingdom, and (2) Mn levels in betel quids, its individual components and other Bangladeshi foods.

RESULTS

Betel quid chewers displayed a significantly higher (P = 0.009) mean Mn concentration in urine (1.93 μg L(-1)) compared to non-chewers (0.62 μg L(-1)). High levels of Mn were detected in Piper betel leaves with an overall average of 135 mg kg(-1) (range 26 -518 mg kg(-1)). The mean concentration of Mn in betel quid was 41 mg kg(-1) (SD 27) and the daily intake of Mn in the Bangladeshi population was estimated to be 20.3 mg/day. Chewing six betel quids could contribute up to 18% of the maximum recommended daily intake of Mn.

CONCLUSION

We have demonstrated that Mn in betel quids is an overlooked source of exposure to Mn in humans. Chewers display a 3.1 fold increased urinary Mn concentration compared to non-chewers. The practice of betel quid chewing contributes a high proportion of the maximum recommended daily intake of Mn, which could make chewers in Bangladesh more vulnerable to Mn neurotoxicity.

Daily intake of manganese by local population around Kylleng Pyndengsohiong Mawthabah (Domiasiat), Meghalaya in India

Present work is carried out adjacent to world's highest rainfall area Kylleng Pyndengsohiong (KP) Mawthabah (Domiasiat), Meghalaya in India to establish the baseline value of manganese intake through dietary route by the local tribe population in view of proposed uranium mining. The locally available food items collected from villages surrounding the proposed uranium mining site at KP Mawthabah (Domiasiat) were analysed using Energy Dispersive X-Ray Fluorescence (EDXRF) Technique. The manganese concentration in different food categories varies from 2.76-12.50 mg kg(-1) in cereals, 1.8-4.20 mg kg(-1) in leafy vegetables, 0.30-13.50 mg kg(-1) in non leafy vegetables, 0.50-15.30 mg kg(-1) in roots and tubers, 0.70-1.50 mg kg(-1) in fruits and 0.12-0.96 mg kg(-1) in flesh food. The mean dietary intake of Mn was found to be 3.83+/-0.25 mg d(-1) compared to Recommended Dietary Allowances (RDAs) of 2-5 mg d(-1). The daily intake of Manganese by the local tribe population is comparable with the value (3.7 mg d(-1)) recommended by International Commission on Radiological Protection (ICRP) for reference man and lower than the intake value observed for Indian and other Asian population.

Assessment of daily intake of trace elements due to consumption of foodstuffs by adult inhabitants of Rio de Janeiro city

Concentrations of Al, Cd, Cr, Cu, Mn, Ni, Pb, U and Zn were determined in vegetables (leafy vegetables, fruit, root, grain and cereal), derived products (sugar, coffee, manioc flour, wheat flour, corn flour, and pasta) and animal products (meat, fish, milk) most frequently consumed by adult inhabitants of Rio de Janeiro city. A total of 90 samples were analyzed using inductively coupled plasma mass spectrometry (ICPMS) as the principal method following sample dissolution by dry and wet ashing. Generally, highest contributions for the intake of micronutrients (Cu, Mn, Ni and Zn) arise from bean, rice and wheat flour consumption. Meat, cow milk and the flours, wheat and manioc, are major sources of Al, Cd, Pb and U intake. The daily intake of nine elements via foodstuffs was estimated as: 3.4x10(-4) mg of U, 1.8x10(-3) mg of Cd, 2.8x10(-2) mg of Pb, 2.3x10(-2) mg of Cr, 8.9x10(-2) mg of Ni, 1.12 mg of Cu, 2.5 mg of Mn, 3.5 mg of Al and 4.8 mg of Zn. The intake of toxic elements ranged between 2.7% (Cd) and 30% (U) of the provisional tolerable daily intake and reference dose values indicating that food consumption is, at present, no critical factor for the uptake of these toxic metals, in the population studied here. Concerning micronutrients, the recommended values of daily intake of Cu and Mn are conveniently supplied by the diet; however, for Cr and Zn they are lower than the recommend daily allowance. Due to high metal concentrations and consumption rates, black bean is the foodstuff that provided the highest ingestion rates of Cu, Mn, Ni and Zn (36-60% of the reference dose), being therefore a very important source of micronutrient supply.

Oral manganese intake estimated with dietary records and with direct chemical analysis

The estimation of the daily oral intake of manganese (Mn) can vary significantly with the method used. This study aims to compare two different approaches: the use of dietary records along with tables of the Mn contents of different foods and the parallel collection of identical aliquots which are analyzed for Mn. Dietary samples and information were collected during a 3-day dietary assessment with five participants. The average daily oral intake of Mn estimated from the dietary records and tables of Mn contents was 3.52 mg/day (S.D. = 1.9), which corresponds to an exposure dose (ED) of 50.27 microg/kg body wt./day (S.D. = 26.2). With a parallel collection of identical aliquots and chemical analysis, the average intake was 2.88 mg/day (S.D. = 0.64) for an ED of 41.18 microg/kg body wt./day (S.D. = 8.9). Thus, the use of tables gives an estimated oral dose 22% higher than the more accurate direct chemical analysis.

Selenium levels in biological matrices in adult population of Mumbai, India

Selenium (Se) levels in whole blood, serum, urine, muscle and saliva of Mumbai adults have been estimated by differential pulse cathodic stripping voltammetry (DPCSV); the detection limit of Se is 0.05 ng ml(-1). The reliability of estimation is further assessed through the analysis of Standard Reference Materials. The Se levels in whole blood (n = 35) and blood serum (n = 201) of the Mumbai adult population is 99.6 and 100 ng ml(-1); approximately 34.8% of the population have serum Se levels between 80 and 100 ng ml(-1). The blood serum levels of Se for Mumbai adults are comparable to those of whole blood. The mean concentration of Se in urine on a 24-h basis is 5.2 ng ml(-1). Muscle and saliva of the Mumbai adult population contain 195.4 ng g(-1) and 2 ng ml(-1) of Se, respectively. A good correlation between serum Se and dietary Se is observed with a correlation coefficient of 0.89.

Blood lead and its effect on Cd, Cu, Zn, Fe and hemoglobin levels of children

The levels of heavy metals, such as Pb, Cd, Cu, Zn and Fe, in whole blood samples of Mumbai and Hyderabad children have been determined. In the present study, 576 blood samples of children (3-6 years old) were collected during 1996-1998 and analyzed for heavy metal contents by anodic stripping voltammetry and atomic absorption spectrometry. The geometric mean concentrations of Pb, Cd, Cu and Zn in blood of Mumbai children were 8.0, 0.10, 86.5 and 398.9 microg dl(-1), while those for Hyderabad children were 13.3, 0.13, 100.6 and 483.4 microg dl(-1) respectively. The geometric mean concentrations of Fe in the blood of Mumbai and Hyderabad children were 21.9 and 34.5 mg dl(-1), respectively. Of the Mumbai children, 61.8% were found to have a blood lead concentration lcss than 10 microg dl(-1), while the corresponding proportion of Hyderabad children was 27.4%. Higher concentrations of Pb in the children's blood were observed at high traffic areas in both cities. A decreasing trend in the hemoglobin content with increasing blood lead levels was observed for Mumbai children. A good negative correlation (-0.61) between the blood lead and iron has been observed for Mumbai children The hemoglobin content of 85% of the study population was found to vary between 8 and 14 g%.

Daily intake of trace metals through coffee consumption in India

The trace element contents of five varieties of instant coffee powder available in the Indian market have been analysed. Ca, Cr, Fe, K, Mg, Mn, Ni, Sr, Zn and Pb, Cd, Cu have been determined using atomic absorption spectrophotometry and differential pulse anodic stripping voltammetry, respectively. The metal levels in the coffee powders observed in this study are comparable with those reported for green coffe beans (Arabica and Robusta variety) reported worldwide with the exception of Sr and Zn, which were on the lower side of the reported values. Concentrations of these metals have been converted into intake figures based on coffee consumption. The daily intakes of the above metals through ingestion of coffee are 1.4 mg, 1.58 microg, 124 microg, 41.5 mg, 4.9 mg, 17.9 microg, 2.9 microg, 3.8 microg, 12.5 microg, 0.2 microg, 0.03 microg and 15.5 microg, respectively. The values, which were compared with the total dietary, intake of metals through ingestion by the Mumbai population, indicate that the contribution from coffee is less than or around 1% for most of the elements except for Cr and Ni which are around 3%.