Energy dispersive X-ray fluorescence detection of heavy metals in Bangladesh cows' milk

Evaluation of essential and trace metals/metalloids distribution and probable human health risk implications from branded liquid and powder milks available in Dhaka City, Bangladesh

The processed forms of milk, branded liquid, and power milk available in Dhaka city, the capital of Bangladesh, were investigated for essential and trace metal/metalloids regarding nutritional and human health risk aspects. For this, the potential nutritional contribution, estimated daily intake (EDI) and non-carcinogenic risk for six different life stages with male and female categories, as well as the carcinogenic risk for children and adults of both genders, were addressed. In total, 46 branded liquid and powder milk samples were considered for this analysis employing atomic absorption spectroscopy. The concentration of essential elements showed the trends of K > Ca > Na > Mg > Fe > Zn > Mn > Cu and K > Ca > Na > Mg > Fe > Cu > Mn > Zn for liquid and powder milk samples, respectively, but the potentially hazardous one showed the same trends (Cr > Pb > Hg > As > Cd) for both items. Except for Cr, Hg, and Fe, the elemental compositions of both milk categories differed considerably (< 0.05). Compared to the threshold values for milk samples (liquid and powder), Fe (19% and 27%), Mn (100% and 63%), Cu (0% and 23%), Zn (94% and 0%), Pb (25% and 13%), and Cr (0% and 3%) showed above the permissible limits. The nutrient input was the highest for Ca (27.2% and 18.7%), followed by Mg, K, and Na. The EDI of studied elements was within the daily permissible limit in both the milk category (except age group (≤ 3) and the female category). The non-carcinogenic risk assessment showed that the age groups ≤ 3 for liquid milk and ≤ 3 and 3 < X ≤ 14 with female categories for powder milk exceeded the threshold level (> 1) in the case of Cr, Cd, As, Zn, and Mn. The probable carcinogenic risks indicated an unacceptable risk level (< 1.00E-04) for the ingestion of Cr through powder milk samples for children in male and female categories. Finally, it believes that green cow farming practices and green milk processing technology, as well as continuous monitoring of toxic metals, can limit the ultimate risk worldwide.

Preparation of pyridoxine-based polyurethane modified sensors and their use in simultaneous determination of Cu(II) - Co(II) ions

In this study, pyridoxine-based polyurethane-modified electrodes were prepared to simultaneously and sensitively measure copper (Cu(II)) and cobalt (Co(II)) ions in complex matrix samples. For the production of the electrodes, firstly, the synthesis of pyridoxine-based polyurethane structures was carried out. In these syntheses, the polymer structure was diversified by using different isocyanates. Polyethyleneglycol-200 (PEG), pyridoxine (B6), and β-cyclodextrin (β-CD) groups were used as the source of polyol. The synthesized polyurethane structures were characterized by different instrumental techniques and used in gold electrode surface modification. Modified sensor surfaces were examined by scanning electron microscopy and atomic force microscopy techniques. The prepared modified sensors were used for the simultaneous detection of Cu(II) and Co(II) ions using the differential pulse voltammetry technique. The limit of detection (LOD), limit of quantitation (LOQ), and R2 values for Cu(II) ions were calculated as 8.81 μM, 29.4 μM, and 0.993, respectively. LOD, LOQ, and R2 values for Co(II) ions were calculated as 9.84 μM, 32.8 μM, and 0.9935, respectively. For repeatability, the relative standard deviation (RSD %) of the prepared simultaneous sensors was determined as 1.54 and 1.71 for Cu(II) and Co(II), respectively. As a result, Cu(II) and Co(II) ions were measured independently and simultaneously with high sensitivity. According to these results, it is predicted that pyridoxine-based polyurethane-modified sensors may be suitable for the simultaneous detection of Cu(II) and Co(II) in medical, food, and agricultural samples.

Health risk assessment of arsenic, lead and cadmium from milk consumption in Punjab, India

Milk is an integral part of the human diet and its contamination with heavy metals may alter the health of its consumers. The study was conducted to assess the health risk associated with the heavy metals in milk samples collected from urban and rural households of Ludhiana and Bathinda districts of Punjab, India. One hundred and fifty milk samples were analyzed for heavy metals i.e. arsenic, cadmium, lead and mercury using Inductively Coupled Plasma Mass Spectrometry ICP-MS. The health risks, such as non-carcinogenic and carcinogenic risks from heavy metals in milk samples, were calculated for selected males and females of adults, children and elderly subjects. The results indicated that the arsenic, cadmium and lead content in milk samples were within permissible limit whereas mercury was not detected in any sample. The mean values showed that the selected urban and rural population of both districts was safe from non-carcinogenic risk associated with heavy metal content of milk. However, urban (50% males and 86% females) and rural (25% males) children of Bathinda district were at risk of cancer from arsenic and cadmium present in milk samples, respectively. It was also observed that the selected population of both districts were safe from carcinogenic risk due to the combined effects of heavy metals. It was concluded that even with a small amount of heavy metal in milk samples, the rural adults, rural male children and urban female children of Bathinda district had carcinogenic risk due to milk consumption. Hence, regular monitoring and testing of milk samples must be done as a public health measure to prevent heavy metal contamination in milk to safeguard the health of consumers.

Nanoemulsion-based silver ion-selective optode based on colorimetrically silver ion-responsive ionic liquid-based dye

In this study, we describe the fast-responsive nanoemulsion (NE)-based silver ion (Ag⁺)-selective optode based on colorimetrically silver ion-responsive ionic liquid-based dye (ILD). The ILD comprises purely functional sensing molecules, a protonated cationic merocyanine dye (KD-M13-H⁺) and an anionic Ag⁺ ionophore (BDM-SO₃^-), and thus, it can be used for highly sensitive silver ion (Ag⁺) sensing due to the extremely high content of dye in the organic phase (ionic-liquid phase). However, during the Ag⁺ sensing, the cationic merocyanine dye is converted into electrically neutral form by deprotonation of the dye, which leads to the conversion of liquified dye into solid form in the organic phase, which makes the response time slower when ILD is used for poly(vinyl chloride) (PVC) membrane-based ion-selective optode, especially for sensing of high Ag⁺ concentration. To solve this problem, we focused on the use of the nano-emulsification technique. The response time of the ILD-based nanoemulsion (NE) was considerably shorter (1 s) compared to that of the ILD-based PVC membrane (a few minutes) owing to the large surface area and excellent diffusivity of the emulsion. The ILD-based NE contained a very high dye concentration (833 mmol kg^-1) and exhibited approximately 12 times higher sensitivity than that of the plasticizer-based conventional NE. In the cation measurements, the ILD-based NE responded to Ag⁺ via a cation-exchange mechanism and demonstrated a highly selective response to Ag⁺ (log [Formula: see text] = - 3.0). ILD-NE was successfully applied to the detection of spiked Ag⁺ in a tap water sample with recoveries of 98 - 103% with a relative standard deviation (RSD) of less than 5%. In comparison with NE based on non-ionic ionophores without charge, NE based on BDM-SO₃^- responded to lower Ag⁺ concentrations owing to the effect of negative charge on the binding property. The novel ILD-based NE was capable of highly sensitive, rapid, and selective Ag⁺ sensing, providing potential for analytical devices applicable to high-performance on-site analysis.

Determination of Heavy Metal Levels and Health Risk Assessment of Raw Cow Milk in Guelma Region, Algeria

During the recent decades, adverse effects of unexpected contaminants, such as heavy metals on raw cow milk quality, have threatened human health. The objective of this study was to determine heavy metal levels in raw milk collected from autochthonous bovine breeds in the eastern region of Algeria. Eighty-eight pooled milk samples were analyzed using atomic absorption spectrometry for Pb, Cd, Cr, Cu, Ni, Fe, and Zn, and dietary risks were estimated for infants, children, and adults with minimum, average, and maximum milk consumption scenarios. Results revealed that Pb (0.94 ± 0.49 mg/kg), Cd (0.03 ± 0.01 mg/kg), and Cu (0.14 ± 0.08 mg/kg) levels in all analyzed samples were higher than their corresponding maximum residue levels (MRLs). The task hazard quotient (THQ) values suggest potential risk for infants in the three scenarios from Pb, Cd, and Cr; for children in the three scenarios from Pb and in the high scenario from Cr; and for adults in the medium and high scenarios from Pb. The hazard index (HI) values were higher than 1, and the contributions of each metal to the overall HI followed a descending order of Pb, Cr, Cd, Ni, Zn, Cu, and Fe with values of 68.19%, 15.39%, 6.91%, 4.94%, 3.42%, 0.88%, and 0.28%, respectively. Our results indicated that there may be a potential risk of heavy metals, especially Pb, for infants through raw cow milk consumption. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metal effects in future studies.

Recent advances in instrumental techniques for heavy metal quantification

Heavy metals (HMs) are ubiquitous; they are found in soil, water, air, and all biological matrices. The toxicity, bioaccumulation potential, and deleterious effects of most of these metals on humans and the environment have been widely documented. Consequently, the detection and quantification of HMs in various environmental samples have become a pressing issue. The analysis of the concentrations of HMs is a vital component of environmental monitoring; hence, the selection of the most suitable analytical technique for their determination has become a topic of great interest in food, environment, and human health safety. Analytical techniques for the quantification of these metals have evolved. Presently, a broad range of HM analytical techniques are available with each having its outstanding merits as well as limitations. Most analytical scientists, therefore, adopt complementation of more than one method, with the choice influenced by the specific metal of interest, desired limits of detection and quantification, nature of the interference, level of sensitivity, and precision among others. Sequel to the above, this work comprehensively reviews the most recent advances in instrumental techniques for the determination of HMs. It gives a general overview of the concept of HMs, their sources, and why their accurate quantification is pertinent. It highlights various conventional and more advanced techniques for HM determination, and as one of its kind, it also gives special attention to the specific merits and demerits of the analytical techniques. Finally, it presents the most recent studies in this regard.

Ab initio calculation of the adsorption of As, Cd, Cr, and Hg heavy metal atoms onto the illite(001) surface: Implications for soil pollution and reclamation

Elucidating the mechanisms of heavy metal (HM) adsorption on clay minerals is key to solving HM pollution in soil. In this study, the adsorption of four HM atoms (As, Cd, Cr, and Hg) on the illite(001) surface was investigated using density functional theory calculations. Different adsorption configurations were investigated and the electronic properties (i.e., adsorption energy (E_ad) and electron transfer) were analyzed. The E_ad values of the four HM atoms on the illite(001) surface were found to be As > Cr > Cd > Hg. The E_ad values for the most stable adsorption configurations of As, Cr, Cd, and Hg were -1.8554, -0.7982, -0.3358, and -0.2678 eV, respectively. The As atoms show effective chemisorption at all six adsorption sites, while Cd, Cr, and Hg atoms mainly exhibited physisorption. The hollow and top (O) sites were more favorable than the top (K) sites for the adsorption of HM atoms. The Gibbs free energy results show that the illite(001) surface was energetically favorable for the adsorption of As and Cr atoms under the influence of 298 K and 1 atm. After adsorption, there was a redistribution of positions and reconfiguration of the chemical bonding of the surface atoms, with a non-negligible influence around the upper surface atoms. Bader charge analysis shows electrons were transferred from the surface to the HM atoms, and a strong correlation between the valence electron variations and the adsorption energy was observed. HM atoms had a high electronic state overlap with the surface O atoms near the Fermi energy level, indicating that the surface O atoms, though not the topmost atoms around the surface, significantly influence HM adsorption. The above results show illite(001) preferentially adsorbed As among all four investigated HM atoms, indicating that soils containing a high proportion of illite might be more prone to As pollution.

Trace element bioaccumulation in edible red seaweeds (Rhodophyta): A risk assessment for consumers

As a precursor to risk assessment and risk management through consuming contaminated seafood, food safety needs to be quantified and assured. Seaweed is an increasing dietary component, especially in developing countries, but there are few studies assessing uptake rates of contaminants from this route. As such, the present study determined likely human uptake due to the trace elemental (Fe, Mn, Ni, Cu, Zn, Se, Hg, and As) concentrations in the edible red seaweeds (Rhodophyta) Gelidium pusillum and Hypnea musciformis, growing in the industrialised Cox's Bazar coastal area of Bangladesh. Metal and metalloid concentrations in G. pusillum were in the order (mg/kg): Fe (797 ± 67) > Mn (69 ± 4) > Ni (12 ± 5) > Zn (9 ± 4) > Cu (9 ± 4) >Se (0.1 ± 0.1) > Hg (0.1 ± 0.01), and in H. musciformis: Fe (668 ± 58) > Mn (28 ± 5) > Ni (14 ± 2) > Zn (11 ± 5) > Cu (6 ± 4) >Se (0.2 ± 0.03) > Hg (0.04 ± 0.01). Despite the industrial activities in the area, and based on 10 g. day^-1 seaweed consumption, it is concluded that these concentrations pose no risk to human health as part of a normal diet according to the targeted hazard quotient and hazard index (THQ and HI) (values < 1). In addition, and as a novel aspect for seaweeds, Selenium Health Benefit Values (Se-HBV) were determined and found to have positive values. Seaweed can be used as an absorber of inorganic metals for removing contamination in coastal waters. The results are a precursor to further research regarding the efficiency and rate at which seaweeds can sequester metal contamination in water. In addition, management techniques need to be developed thereby to control the contaminant inputs.

Heavy Metals in Unprocessed or Minimally Processed Foods Consumed by Humans Worldwide: A Scoping Review

Heavy metals (HM) can be accumulated along the food chain; their presence in food is a global concern for human health because some of them are toxic even at low concentrations. Unprocessed or minimally processed foods are good sources of different nutrients, so their safety and quality composition should be guaranteed in the most natural form that is obtained for human consumption. The objective of this scoping review (ScR) is to summarize the existing evidence about the presence of HM content (arsenic (As), lead (Pb), cadmium (Cd), mercury (Hg), methylmercury (MeHg), and aluminum (Al)) in unprocessed or minimally processed foods for human consumption worldwide during the period of 2011–2020. As a second objective, we identified reported HM values in food with respect to Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) International Food Standards for Maximum Limits (MLs) for contaminants in food. This ScR was conducted in accordance with the Joanna Briggs Institute (JBI) methodology and PRISMA Extension for Scoping Reviews (PRISMA-ScR); advance searches were performed in PubMed, ScienceDirect and FAO AGRIS (Agricultural Science and Technology Information) databases by two reviewers who independently performed literature searches with specific eligibility criteria. We classified individual foods in food groups and subgroups according to the Global Individual Information Food Consumption Data Tool (FAO/WHO GIFT). We homologated all the reported HM units to parts per million (ppm) to determine the weighted mean HM concentration per country and food group/subgroup of the articles included. Then, we compared HM concentration findings with FAO/WHO MLs. Finally, we used a Geographic Information System (GIS) to present our findings. Using our search strategy, we included 152 articles. Asia was the continent with the highest number of publications (n = 79, 51.3%), with China being the country with the largest number of studies (n = 34). Fish and shellfish (n = 58), followed by vegetables (n = 39) and cereals (n = 38), were the food groups studied the most. Fish (n = 42), rice (n = 33), and leafy (n = 28) and fruiting vegetables (n = 29) were the most studied food subgroups. With respect to the HM of interest, Cd was the most analyzed, followed by Pb, As, Hg and Al. Finally, we found that many of the HM concentrations reported exceeded the FAO/OMS MLs established for Cd, Pb and As globally in all food groups, mainly in vegetables, followed by the roots and tubers, and cereals food groups. Our study highlights the presence of HM in the most natural forms of food around the world, in concentrations that, in fact, exceed the MLs, which affects food safety and could represent a human health risk. In countries with regulations on these topics, a monitoring system is recommended to evaluate and monitor compliance with national standards. For countries without a regulation system, it is recommended to adopt international guidelines, such as those of FAO, and implement a monitoring system that supervises national compliance. In both cases, the information must be disseminated to the population to create social awareness. This is especially important to protect the population from the consumption of internal production and for the international markets of the globalized world.

Alleviating Heavy Metal Toxicity in Milk and Water through a Synergistic Approach of Absorption Technique and High Voltage Atmospheric Cold Plasma and Probable Rheological Changes

In this study, we combined atmospheric pressure cold plasma, a novel treatment technology, with an absorption technique with soybean husk to remove Pb and Cd from milk. Different combinations of treatment duration, voltage, and post treatment retention time were used to determine the effectiveness of cold plasma. Soybean husk was used for metal extraction, and it was observed that when the milk samples were plasma treated with a discharge voltage of 50 kV for 2 min and held for 24 h, the highest mean elimination of about 27.37% for Pb and 14.89% for Cd was obtained. Reactive oxygen and nitrogen species produced from plasma treatment were identified using Optical Emission Spectra analysis. A high voltage of 50 kV plasma for a 2 min duration could produce 500 ± 100 ppm of ozone concentration inside the treated package. The value of ΔE, which indicates overall color difference measurement, was significantly (p < 0.05) higher in all the treated samples than control samples. However, in the frequency range from 0.01 to 100 Hz, there was not much difference between the control and treated sample in the frequency sweep test. The identified functional groups at different wavenumbers (cm−1) in the treated samples were found to be similar compared to the control samples.

Assessment of contamination level, pollution risk and source apportionment of heavy metals in the Halda River water, Bangladesh

This study demonstrates the level of heavy metal pollution in the Halda River, the only natural breeding source of carps in Bangladesh. Water was collected from 12 different sampling points along the Halda River. Water at various locations was found satisfactory in terms of the assessed physicochemical parameters (pH, electrical conductivity, and total dissolved solids). The presence of various cations and anions was also studied using ion chromatography. Atomic absorption spectroscopy was used to identify and quantify various heavy metals in the collected water samples. Among the heavy metals, Cd, Cr, Fe, Pb, Cu, and As concentration exceeded the safe limit suggested by WHO. The calculated heavy metal pollution index and metal index were found higher than the critical index value. The single-factor assessment (P _i) and Nemerow's multi-factor index (P _N) of heavy metals was calculated to find out the degree of pollution in the Halda River. The maximum values of P _i (Cd), P _i (Pb), P _i (As), P _i (Cu), and P _i (Cr) were determined to be 26.67, 260.00, 17.00, 208.76 and 2.80 respectively. The maximum value of P _N was found to be 289.04. The discharge of effluents from various large and small industries near the Halda River is considered to be the major source of the identified heavy metals. Multivariate statistical analysis such as principal component analysis, Pearson correlation matrix and cluster analysis revealed that most of the heavy metals originated from different anthropogenic sources. Multivariate analysis also showed that Co, Mn, Cu, Cr, Pb, Cd, NH₄⁺, NO₃^- mainly came from artificial sources whereas Fe, Ca, As mainly originated from natural sources. Arsenic (As) also came from artificial sources with Cu.

Toxic element profile of ice cream in Bangladesh: a health risk assessment study

Ice cream is a popular frozen dairy product and a possible source of dietary minerals. However, ice cream may also contain toxic metals, which may cause several health implications. The current study aimed to determine the content of toxic elements in ice cream samples using inductively coupled plasma-optical emission spectrometry (ICP-OES) and to assess the health risks of consumers based on target cancer risk (TCR), target hazard quotient (THQ), and hazardous index (HI). The determined concentration (median, range) of all studied elements had shown a descending order of Al (9.36, 5.37-14.26) > Zn (5.94, 1.95-10.22) > Cu (1.73, 1.02-3.77) > Ni (0.95, 0.67-1.80) > Fe (0.79, 0.10-1.64) > Cr (0.43, 0.28-0.73) > Mn (0.42, 0.11-1.03) > Pb (0.34, 0.09-0.79) > Cd (0.08, 0.04-0.14) mg/kg (fresh weight). The values of THQ and HI (except 16% for children) were lower than the maximum threshold risk limit (TRL = 1.0), indicating no potential non-carcinogenic health effects might occur. Similarly, the TCR of Cr and Pb for both adults and children was within the permissible limit of 10^-4-10^-6, which suggested that the consumer would not experience potential lifetime carcinogenic health risks. However, the overall analyses revealed that the consumption of ice cream is almost safe for people, but the combined impact of all metals (HI) in some samples is a matter of health concern. Henceforth, regular monitoring of toxic metals in ice creams should be done to assure food safety and hygiene.

Toxic heavy metals and nutrient concentration in the milk of goat herds in two Iranian industrial and non-industrial zones

This work aimed to explore the concentration of nickel, manganese, iron, copper, chromium, and lead in the milk of goat herds in the industrial area of Asaluyeh (southern Iran) and the non-industrial area of Kaki. The milk of 16 goat herds (each herd had at least ten goats) was collected in several villages in each area, and at the same time, the drinking water and forage of goats were sampled. The concentration of elements in the samples was determined by ICP-OES. The mean concentrations of chromium, copper, iron, manganese, lead, and nickel in milk samples of the Asaluyeh area were 16.423 ± 0.349, 0.146 ± 0.118, 6.111 ± 0.501, 0.239 ± 0.016, 0.141 ± 0.030, and 1.447 ± 0.101 mg/kg, respectively. Concentrations of heavy metals (except for copper) in the milk of goats in the industrialized area of Asaluyeh were significantly higher than that of Kaki (P < 0.05). Also, the content of heavy metals was significantly correlated with lactose levels (P < 0.05). The hazard index for drinking the goat milk was computed to be 0.444 and 0.386 for the Asaluyeh and Kaki area, respectively, which shows a minimal effect of this exposure pathway.

Heavy metals levels in raw cow milk and health risk assessment across the globe: A systematic review

This systematic review presents the potential toxicity of heavy metals such as lead (Pb), mercury (Hg), cadmium (Cd), iron (Fe), nickel (Ni), aluminum (Al), and copper (Cu) in raw cow milk, focusing on their contamination sources and on the assessment of the related human health risk. Multiple keywords such as "raw cow milk, heavy metals, and human health" were used to search in related databases. A total of 60 original articles published since 2010 reporting the levels of these metals in raw cow's milk across the world were reviewed. Data showed that the highest levels of Ni (833 mg/L), Pb (60 mg/L), Cu (36 mg/L) were noticed in raw cow milk collected in area consists of granites and granite gneisses in India, while the highest level of Cd (12 mg/L) was reported in barite mining area in India. Fe values in raw cow milk samples were above the WHO maximum limit (0.37 mg/L) with highest values (37.02 mg/L) recorded in India. The highest Al level was (22.50 mg/L) reported for raw cow's milk collected close to food producing plants region in Turkey. The Target Hazard Quotients (THQ) values of Hg were below 1 suggesting that milk consumers are not at a non-carcinogenic risk except in Faisalabad province (Pakistan) where THQ values = 7.7. For the other heavy metals, the THQ values were >1 for Pb (10 regions out of 70), for Cd (6 regions out of 59), for Ni (3 out of 29), and for Cu (3 out of 54). Exposure to heavy metals is positively associated with diseases developments. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metals effects in future studies.

Paper-based cation-selective optode sensor containing benzothiazole calix[4]arene for dual colorimetric Ag+ and Hg2+ detection

A new paper-based analytical device based on bulk ion-selective optodes (ISOs) for dual Ag⁺ and Hg²⁺ detection has been developed. A plasticized PVC hydrophobic phase composed of 25,27-di(benzothiazolyl)-26,28-hydroxycalix[4]arene (CU1) as an ion-selective ionophore, potassium tetrakis(4-chlorophenyl)borate as an ion-exchanger and chromoionophore XIV as a lipophilic pH indicator was entrapped in the pores of cellulose paper. This paper strip showed higher selectivity for Ag⁺ and Hg²⁺ over common alkali, alkaline earth and some transition metal ions with a color change from blue to yellow. With the proposed sensor, Ag⁺ and Hg²⁺ can be measured with the range of 1.92 × 10^-6 to 5.00 × 10^-3 M for Ag⁺ and 5.74 × 10^-7 to 5.00 × 10^-5 M for Hg²⁺ with a limit of detection of 1.92 × 10^-6 M for Ag⁺ and 5.74 × 10^-7 M for Hg²⁺. The proposed sensor was successfully applied to determine the amount of mercury in various water sources and the amount of silver in cleaning product samples containing silver nanoparticles (AgNPs). The results were in good agreement with inductively couple plasma-optical emission spectrometric measurements (ICP-OES).