Wet digestion methods

Exploration of Toxic and Essential Metals in Popular Rice Grains of Bangladesh and Associated Human Health Risk Implications

In order to evaluate the benefits as well as the impacts of essential and toxic metals regarding human health, the six common rice grains (katarivhog, bashful, banglamoti, najirshail, branded miniket and loose miniket) were collected from four wholesale markets in Dhaka, the capital of Bangladesh, and were analyzed with different atomic absorption spectroscopy (AAS) techniques. The mean concentrations of the toxic metals Pb, Cd, Cr, and As had 0.299 ± 0.017, 0.157 ± 0.012, 1.33 ± 0.084, and 0.120 ± 0.006 mg/kg, respectively, while those of the essential metals Fe, Cu, Zn, Na, Ca, and Mg had 7.90 ± 0.447, 3.11 ± 0.097, 10.6 ± 0.340, 37.4 ± 0.622, 90.1 ± 7.70, and 115.8 ± 1.61 mg/kg, respectively. Among them, the mean concentrations of toxic metals (Pb, Cd, Cr, and As) exceeded the maximum allowable concentration in rice set by the Codex Alimentarius Commission (CAC). Risk assessment of the heavy metals Pb, Cd, Cr, As, Fe, Cu, and Zn showed that their estimated daily intakes were below the daily reference doses for adults. However, Cd and Cr individually were found to have the target hazard quotient value close to 1 (threshold limit), indicating that they alone are capable of potential health hazards from continuous rice consumption, while the hazard index has surpassed three units signifying greater danger associated with the current trend of consumption. A very high chance of developing cancer in the near future is predicted by incremental lifetime carcinogenic risk (ILCR) analysis for continued intake of Cr (ILCR > 1E-03), and a moderate to high risk is predicted for other carcinogenic substances (Pb, Cd, and As) (ILCR in between 1E-03 and 1E-05) with present rice consumption. The contribution of the essential metals to the RNI revealed that Cu from rice contributes more than 100% in most samples, and the overall contribution is in the following order: Cu > Zn > Fe > Mg > Ca > Na. To ensure the safety of staple foods for human health, it ought to be necessary to design a plan to measure the budget of hazardous metals from all sources with proper surveillance by relevant authorities.

Heavy metal and microbial testing of selected cosmetic products in the Palestinian market

Excessive and continuous use of cosmetic products containing heavy metals can lead to harmful effects. International regulations mandate limited quantities of heavy metals contamination in cosmetic preparations to ensure consumer safety. This research aims to evaluate heavy metal and microbial contamination levels in selected cosmetic products available in the Palestinian market. We collected 35 samples randomly from 23 companies, representing four product types, and analyzed them for the presence of seven heavy metals: zinc (Zn), cadmium (Cd), lead (Pb), chromium (Cr), iron (Fe), copper (Cu), and arsenic (As) using an atomic absorption spectrometer. We also interviewed pharmacists who sold these cosmetics to assess their knowledge of allowed limits and toxic effects associated with increased heavy metal content in cosmetics. The results indicated that all tested products exceeded the allowed limit for Cd (9.5 ± 2.3 ppm), Cu (33.8 ± 9.2 ppm), and Zn (151.0 ± 7.4 ppm). However, none of the tested samples showed microbial contamination. These findings underscore the significant heavy metal contamination of cosmetics present in the Palestinian market. Thus, there is a pressing need to register and quality-test all cosmetic products sold in the Palestinian market and to raise the pharmacists' awareness and knowledge regarding heavy metals in cosmetics.

Potential Health Risks of Zn, Fe, and Pb in Medical Skin Creams and Cosmetic Products Derived from Plants in Iraq

Medical skin creams (SC) and cosmetic products (CP) specially derived from plants have natural chemicals as ingredients which are a major source of heavy metal releases. Therefore, the presence of harmful heavy metals in these materials is a matter of concern. This study has been carried out to assess the concentrations of heavy metals such as zinc (Zn), iron (Fe), and lead (Pb) in skin creams and cosmetic products that are available in Iraqi pharmacies using atomic absorption spectroscopy. Thirty-three samples from different Iraqi pharmacies of beauty creams, including 13 samples of skin creams and ten samples of cosmetic products. Health risk parameters such as chronic daily intake (CDI), total non-cancer risk (H.I.), and total cumulative cancer risk (TCCR) have been calculated. Based on the results, it is found that the average value of Zn, Fe, and Pb concentrations for SC samples in unit mg/kg were 65.33 ± 14.56, 100.52 ± 21.05, and 2.62 ± 0.64, respectively. At the same time, the average value of Zn, Fe, and Pb concentrations for CP samples in unit mg/kg were 2.30 ± 0.48, 24.18 ± 6.87, and 4.79 ± 1.18, respectively. The results of health risk exposure for SC samples were higher than those for CP samples. But, the values of health risk parameters were within acceptable limits according to Environmental Protection Agency (EPA). Consequently, there is no potential health risk for using medical skin creams and cosmetic products in the present study by Iraqi people.

Health Risk Study of Heavy Metals from Consumption of Drugs (Solid and Liquid) Samples Derived from Medicinal Plants in Iraq

Heavy metals are one of the carcinogenic factors harmful to the safety of human health. In plant-based medications, heavy metals can be found. In February 2022, 28 specimens of medicinal drugs (solid and liquid) were collected from Texas drugstores to investigate heavy metals like zinc, iron, and lead utilizing a Shimadzu AA-7000 atomic absorption spectrophotometer (AAS). The current study used a US EPA model to calculate non-cancer and cancer risk parameters for heavy metals in all medicinal drug specimens. Zinc, iron, and lead levels (mg/kg) in solid samples were 1.95-51.43, 29.09-2055.92, and ND-26.68, respectively, while they were 0.043-4.267, 0.100-5.25, and ND-1.434, respectively, in liquid specimens. The average value of total non-cancer risk (TNCR or HII) and total cancer risk (TCCR) of heavy metals intake in solid specimens was 4.54E - 03 ± 1.1E - 03 and 2.11E - 06 ± 6.0E - 07, while in liquid specimens were 1.98E - 04 ± 4.1E - 05 and 9.44E - 09 ± 2.3E - 09, respectively. Compared to liquid specimens, solid specimens have higher concentrations of heavy metals. The zinc, iron, and lead concentrations in the liquid specimens were lower than the WHO-acceptable standards of 50, 20, and 10 mg/kg, respectively. On the other hand, few solid specimen results are more than acceptable. However, all the specimens' TNCR and TCCR results were within the US EPA's globally recommended limits. Finally, the results of the heavy metals show no health hazards associated with using the researched medications.

Development of an eco-friendly sample preparation protocol for metal determination in food samples: an oxygen pressurized single reaction chamber using diluted nitric acid

Many efforts have been recently made to improve the digestion efficiency by using powerful equipment or by using an auxiliary reagent. In this work, an alternative method is reported, which explores a digestion system based on a single reaction chamber (SRC) technology pressurized with O₂ for reducing the amount of acid, without impairing the digestion efficiency. Before digestion, the system was pressurized with compressed air (20 bar, 20% O₂) while the temperature was evaluated from 180 up to 270 °C. The procedure was also carried out under O₂ pressure (20 bar). For each temperature several acid concentrations were evaluated (0.1 to 3 mol L^-1 HNO₃), being possible to correlate the effectiveness of each acid concentration with temperature. The proposed method was applied to the simultaneous digestion of several organic matrices with variable content of fat, protein, and carbohydrate (whole milk powder, bovine liver, parsley, and linseed). The residual carbon content was lower than 4% (C lower than 200 mg L^-1 in digests), showing the high digestion efficiency of the proposed approach. Up to 250 mg of all food matrices were digested using a sub-stoichiometric amount of HNO₃ (1 mol L^-1 solution), which was only achieved due to the use of O₂ as an auxiliary reagent. Barium, Ca, Cu, Fe, K, Mg, Mn, Na, Sr, and Zn were determined by ICP-OES, and the accuracy was better than 95% for standard reference materials of corn bran, whole milk powder, and bovine liver. It is an important feature, being in agreement with green chemistry recommendations because very low amounts of reagents are required for sample digestion, as well as low amounts of residues are generated.

Enhanced digestion of complex cosmetic matrices for analysis of As, Hg, Cd, Cr, Ni, and Pb using triton X-100

A suitable optimized digestion method for lipsticks and powders for the analysis of As, Hg, Cd, Cr, Ni and Pb by Hydride Generation Atomic Absorption Spectrophotometry (HG-AAS), Cold Vapor Atomic Absorption Spectrophotometry (CV-AAS) and Flame Atomic Absorption Spectrophotometry (FAAS) was developed using common acid digestion methods enhanced by the use of Triton X-100. The three acid digestion methods used in this study were Method A (nitric acid and hydrogen peroxide), Method B (nitric acid and hydrochloric acid) and Method C (nitric acid, hydrochloric acid and hydrogen peroxide). Triton X-100 was added to each of these and the effects were studied. The acid digestion method that was determined to be the most suitable and efficient for lipsticks and powders was Method A-1 (nitric acid and hydrogen peroxide with 5% Triton X-100 at 95 °C for 3 h). The range of percentage recoveries obtained were; powders (98.50% to 92. 61%) and lipsticks (100.96% to 99.41%) for As, Cd, Cr, Pb, Hg and Ni. The addition of Triton X-100 significantly improved the efficiency of the method.•

Triton X-100 improves the efficiency of acid digestion of fatty hydrophobic samples by dispersing the sample throughout the acid digestant.

Is the Concentration of Cadmium, Lead, Mercury, and Selenium Related to Preterm Birth?

Environmental pollution and exposure of people to heavy metals cause many bad obstetric outcomes. Our aim is to demonstrate the role of cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) in preterm labor etiology with a case-control study. In this study, between November 2017 and April 2018, preterm delivery mothers and term delivery mothers were compared in Çorum, Turkey. All deliveries were performed with cesarean sections and there were 30 mothers in the control group and 20 in the study group. The maternal blood, maternal urine, umbilical cord blood, and heavy metal levels in the amnion fluid in both groups were studied. Graphite furnace atomic absorption spectrometry was used to determine the blood concentration of Cd, Pb, Hg, and Se. We found lower levels of selenium in blood and urine of preterm delivery mothers and umbilical cord and amnion fluids of preterm infants (p < 0.01). We found a statistically significant positive correlation at selenium levels between mother's blood and umbilical cord blood (r (50) = 0.896, p < 0.001) and between maternal urine and amniotic fluid (r (50) = 0.841, p < 0.001). We have not found a similar correlation between mother and fetus of other metals (p > 0.05). We found that selenium levels were lower in mothers who were preterm birth in the light of the data in our study. We could not determine the positive or negative correlation of Cd, Pb, and Hg levels in blood, urine, and amniotic fluid samples with preterm birth.

Blood Cadmium Concentrations in Women with Ectopic Pregnancy

The purpose of this study is to investigate the relationship between the blood level of cadmium and the occurrence of ectopic pregnancy. Forty-one (41) case patients with ectopic pregnancy and 41 uncomplicated intrauterine pregnant patients as controls were recruited. The concentrations of cadmium (Cd) were measured from blood samples using atomic absorption spectrometry. The cases and controls were similar in age, body mass index, and smoking habits. The median blood level of Cd was 0.32 μg/l (interquartile range [IQR] 0.00-0.71) in the women with ectopic pregnancies and 0.34 μg/l (IQR 0.09-0.59) in the controls. There was no significant association between blood cadmium levels and ectopic pregnancy.

Influence of Digestion Procedure and Residual Carbon on Manganese, Copper, and Zinc Determination in Herbal Matrices by Atomic Absorption Spectrometry

Mineralization to the complete oxidation of sample carbon component does not always assure the best analyte recovery. Particular attention should be paid to the presence of silicon in the investigated plant sample and especially in the certified reference material for which Si content is scarcely given by the providers. During mineralization without addition of the hydrofluoric acid, the residual carbon may block silica surfaces and increase availability of an analyte for its spectral determination in the solution. This issue is of particular relevance because standard protocols for digestion of plant matrices often do not support hydrofluoric acid addition. Several procedures recommended for decomposition of herbal plants were applied for the respective certified reference material and examined in detail. Manganese, copper, and zinc contents were analyzed in all samples by the flame atomic absorption spectrometry. Additionally, the residual carbon was determined in all mineralizates. Silicon content was analyzed by the X-ray fluorescence method. The best recoveries were observed for samples characterized by relatively high residual carbon.

Analytical methods for the determination of halogens in bioanalytical sciences: a review

Fluorine, chlorine, bromine, and iodine have been studied in biological samples and other related matrices owing to the need to understand the biochemical effects in living organisms. In this review, the works published in last 20 years are covered, and the main topics related to sample preparation methods and analytical techniques commonly used for fluorine, chlorine, bromine, and iodine determination in biological samples, food, drugs, and plants used as food or with medical applications are discussed. The commonest sample preparation methods, as extraction and decomposition using combustion and pyrohydrolysis, are reviewed, as well as spectrometric and electroanalytical techniques, spectrophotometry, total reflection X-ray fluorescence, neutron activation analysis, and separation systems using chromatography and electrophoresis. On this aspect, the main analytical challenges and drawbacks are highlighted. A discussion related to the availability of certified reference materials for evaluation of accuracy is also included, as well as a discussion of the official methods used as references for the determination of halogens in the samples covered in this review.

Viscum album versus host (Sorbus aucuparia) as bioindicators of urban areas with various levels of pollution

In this investigation we focus on the concentration of elements in Viscum album and its host (Sorbus aucuparia) as bioindicators of urban pollution. These broadly widespread species, very common in polluted areas may provide important information to monitor environmental quality throughout the year, especially for V. album. Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb and Zn concentrations were measured in the leaves and soil of the tree S. aucuparia as well as in V. album, a semi-parasite living on this tree species. The tree and the semi-parasite were studied in the urban environment of Oława (SW Poland). This area was selected because of the influence of a zinc smelter on the level of metal pollution of soil and plants and to compare the ability of S. aucuparia and V. album to accumulate metals. V. album appeared to be a better bioaccumulator of Cd, Ni, Pb and Zn and a weaker accumulator of Co than S. aucuparia in less polluted sites of Oława. S. aucuparia was a better bioaccumulator of Cd, Ni, Pb and Zn and a weaker accumulator of Co than V. album in more polluted sites. Cluster analysis of Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Ni, Pb and Zn concentrations in plants distinguished sites with lower and higher pollution levels which suggests a possibility of using these species for bioindication. However, the ratio of metals in V. album to S. aucuparia was different depending on the pollution level.

Chemical composition and liberation characterization of printed circuit board comminution fines for beneficiation investigations

Chemical composition and liberation are critical attributes in characterizing a resource stock for beneficiation investigations. Though end-of-life printed circuit board is recognized as a valuable secondary resource stock, no procedural standard exists for the determination of its chemical composition, nor for the -75 microm fines generated during its comminution. The effect of the digestion procedure on the final assays in wet spectroscopic analyses was assessed in this work. Liberation was also explored against literature background. Determination of assays of all constituent elements in printed circuit board comminution fines was found to require comparison of data from more than one digestion condition, while composite particles still persist at the fines sizes, though very few. The discussion reflects how these impact the beneficiation investigations.