Determination of heavy metals in skin-whitening cosmetics using microwave digestion and inductively coupled plasma atomic emission spectrometry

Tetraethylenepentamine-Grafted Amino Terephthalic Acid-Modified Activated Carbon as a Novel Adsorbent for Efficient Removal of Toxic Pb(II) from Water

In this study, a new composite, tetraethylenepentamine (TEPA), was incorporated into amino terephthalic acid-modified activated carbon (ATA@AC) through a one-pot integration of TEPA with the COOH moiety of ATA@AC. This process resulted in the creation of a TEPA@ATA@AC composite for Pb(II) removal from an aquatic environment. Several techniques, including SEM, EDX, FT-IR, TGA, XRD, and Zeta potential, were employed to emphasize the chemical composition, morphology, and thermal durability of the as-synthesized TEPA@ATA@AC composite. The impact of experimental variables on the adsorption of Pb(II) ions was studied using batch adsorption. The uptake assessment suggested that the TEPA@ATA@AC composite exhibited superior Pb(II) removal performance with high removal efficiency (97.65%) at pH = 6.5, dosage = 0.02 g, equilibrium time = 300 min, and temperature = 298 K. The isotherm data exhibited good conformity with the Langmuir isotherm model, whereas the kinetics data displayed strong agreement with both pseudo-first-order and pseudo-second-order kinetics models. This reflected that the Pb((II) uptake by the TEPA@ATA@AC composite was caused by physisorption coupled with limited chemisorption. The greatest monolayer uptake capacity of the TEPA@ATA@AC composite was 432.8 mg/g. The thermodynamic findings indicated that the Pb(II) uptake on the TEPA@ATA@AC composite was an exothermic and feasible process. After five adsorption-desorption runs, the TEPA@ATA@AC composite maintained a superior uptake capacity (83.80%). In summary, the TEPA@ATA@AC composite shows promise as a potent adsorbent for effectively removing Cr(VI) from contaminated water, with impressive removal efficiency.

A systematic review of heavy metals contamination in cosmetics

Background: Globally, the consumption and use of cosmetics have increased exponentially. The presence of hazardous metals raises worries about their potential long-term impacts on human health. Objective: This review's primary goal is to shed light on the presence and ranges of heavy metal concentrations in diverse cosmetic samples as well as the instrumental techniques used by various authors to analyse the hazardous metals in the articles under evaluation. Methodology: This analysis concentrated on 16 publications that measured the levels of heavy metals like lead, cadmium, iron, nickel, chromium, and mercury in various cosmetic samples that were published between the years 2012 and 2020. Results: The study's findings support the existence of these metals as pollutants or components in cosmetics, both of which pose substantial health hazards. The regulations and acceptable limits vary across different countries, which is a significant challenge for the cosmetic industry. Conclusion: Therefore, there is a pressing need to standardise the acceptable limits of these toxic metals in cosmetics. Instrumental techniques such as AAS, GFAAS, ICP-OES/ICP-AES, and ICP-MS were employed by Researchers to analyse the toxic metals in cosmetics.

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.

Statistical Analysis and Health Risk Assessment: Vegetables Irrigated with Wastewater in Kirri Shamozai, Pakistan

One of the primary environmental routes through which humans are exposed to metals and may be exposed to health risks is the food chain's contamination with heavy metals. The study observed the risks posed by contaminants in vegetables produced in soil that received wastewater irrigation, as well as their origins and the human health impacts. Eight harmful metals (Cu, Fe, Zn, Mn, Pb, Cd, Ni, and Cr) were tested for concentration levels in water, soil, and vegetable samples using analytical techniques and an atomic absorption spectrophotometer. The present study investigated the potential health implications associated with the consumption of vegetables irrigated using wastewater containing heavy metals. The results indicated a notable accumulation of heavy metals in plant and soil samples obtained from Kirri Shamozai, Pakistan. In comparison to vegetables cultivated in soil irrigated with fresh water, the concentration levels of heavy metals in vegetables grown on soil irrigated with untreated wastewater were considerably higher at (P ≤ 0.001) and above the World Health Organization (WHO) recommended limits. The results showed that heavy metals had significantly accumulated in the soil and had permeated into the crops. Heavy metal concentrations in vegetables cultivated on land irrigated with wastewater were more significant than those grown on land irrigated with freshwater. They exceeded US EPA and World Health Organization (WHO) limits. PCA results for Pb, Cu, and Cr are the main issues impacting water quality and health hazards. The PCA results show that the soil has an extensive loading of heavy metals Cd, Ni, and Mn.

Wastewater-Irrigated Vegetables Are a Significant Source of Heavy Metal Contaminants: Toxicity and Health Risks

Water contaminated with heavy metals constitutes an important threat. This threat is a real problem with a negative impact in some developing countries where untreated industrial effluents are used for irrigation. The present study examines heavy metals in wastewater-irrigated vegetables (apple gourd, spinach, cauliflower, sponge gourd, and coriander) water, and soil from Chenab Nagar, Chiniot, Pakistan. In particular, the metals quantified were cadmium (Cd), chromium (Cr), cobalt (Co), nickel (Ni), lead (Pb), and manganese (Mn). Among them, Cr and Co in crops irrigated -wastewater exceeded the levels recommended by the World Health Organization (WHO). In contrast, Ni, Cu, Pb, and Mn concentrations were in line with WHO standards. Compared with the limits established by the Food and Agriculture Organization of the United Nations (FAO), all the study vegetables presented higher (thus unsafe) concentrations of Cd (0.38 to 1.205 mg/Kg). There were also unsafe concentrations of Cr in coriander, sponge gourd, and cauliflower. Pb was found at an unsafe concentration (0.59 mg/Kg) in cauliflower. Conversely, Ni and Mn concentrations were below the maximum permissible limits by WHO, and FAO in all of the analyzed samples. The contamination load index (CLI) in soil, bioconcentration factor (BCF) in plants, daily intake of metals (DIM), and health risk index (HRI) have also been evaluated to estimate the potential risk to human health in that area. We have found an important risk of transitions of Pb, Cd, Cr, and Co from water/soil to the edible part of the plant. The highest HRI value associated with Cd (6.10-13.85) followed by Cr (1.25-7.67) for all vegetable samples presented them as high health risk metal contaminants. If the issue is not addressed, consumption of wastewater-irrigated vegetables will continue posing a health risk.

Assessment of level of heavy metals in cosmetics

Background: Toxic metals in cosmetic products can lead to serious health problems among consumers. Skin lightening cosmetics are popular among women who may be unaware of prevalence of toxic metals in such products. Purpose: This study assessed the content of toxic metals in cosmetic products imported into Botswana. There are currently no regulations in Botswana governing maximum contaminants limits for contaminants such as metal ions in cosmetic products. Research Design: Sample analysis was carried out using inductively coupled plasma optical emission spectrometry after microwave-assisted acid sample digestion. Results: Total concentrations of metals were in the order Pb > Ni > Cr > As. The concentrations of metals analysed were in the range of 45.75–193.60; 2.99–9.50; 3.32–7.41 and 1.95–4.52 mg/kg for Pb, Ni, Cr and As respectively. The concentrations of Pb in all 14 samples exceeded the maximum impurity level of 10 mg/kg in cosmetics as per the United States Food and Drug Administration (US FDA). Concentrations of Ni, As and Cr were also higher than the set US FDA limits in some cosmetic samples under study. A human health risk assessment was conducted using hazard quotient, average daily intake and health risk index. A hazard quotient of greater than one was determined for Pb (HQ ∼ 177.0–749.2) in all 14 cosmetic samples investigated indicating potential adverse effects to human health. Conclusion: Overall results of total concentration and health risk assessment indicate that cosmetic products imported into Botswana are harmful to consumers. Therefore, quality control measures should be enforced to ensure metal concentrations in facial cosmetic products do not exceed regulatory limits.

A Systematic Review of Mercury Exposures from Skin-Lightening Products

BACKGROUND

The Minamata Convention on Mercury (Article 4) prohibits the manufacture, import, or export of skin-lightening products containing mercury concentrations above 1 ppm. However, there is a lack of knowledge surrounding the global prevalence of mercury-added skin-lightening products.

OBJECTIVE

The objective of this study was to increase our understanding of worldwide human mercury exposure from skin-lightening products.

METHODS

A systematic search of peer-reviewed scientific literature was performed for relevant articles in four databases (PubMed, Web of Science Core Collection, Scopus, and TOXLINE). The search strategy, eligibility criteria, and data-extraction methods were established a priori. The search identified 2,303 unique scientific articles, of which 41 were ultimately deemed eligible for inclusion after iterative screens at the title, abstract, and whole-text levels. To facilitate data extraction and synthesis, all papers were organized according to four data groups a) "Mercury in products," b) "Usage of products," c) "Human biomarkers of exposure," and d) "Health impacts."

RESULTS

This review was based on data contained in 41 peer-reviewed scientific papers from 22 countries worldwide published between 2000 and 2022. In total, we captured mercury concentration values from 787 skin-lightening product samples [overall pooled central median mercury level was 0.49μg/g; interquartile range (IQR): 0.02-5.9] and 1,042 human biomarker measurements from 863 individuals. We also synthesized usage information from 3,898 individuals and self-reported health impacts associated with using mercury-added products from 832 individuals.

DISCUSSION

This review suggests that mercury widely exists as an active ingredient in many skin-lightening products worldwide and that users are at risk of variable and often high exposures. These synthesized findings identify data gaps and help increase our understanding of the health risks associated with the use of these products. https://doi.org/10.1289/EHP10808.

Analysis of Prohibited and Restricted Ingredients in Cosmetics

The general public uses cosmetics daily. Cosmetic products contain substances (ingredients) with various functions, from skincare to enhancing appearance, as well as ingredients that preserve the cosmetic products. Some cosmetic ingredients are prohibited or restricted in certain geographical regions, such as the European Union and the United States of America, due to their potential to cause adverse effects such as cancer, birth defects, and/or developmental and reproductive disorders. However, the ingredients may be used in other regions, and, hence, the monitoring of the cosmetic ingredients actually used is important to ensure the safety of cosmetic products. This review provides an overview of recent analytical methods that have been developed for detecting certain ingredients that are restricted or prohibited by the U.S. Food and Drug Administration (FDA) and/or EU legislation on cosmetic products.

Sample Preparation of Cosmetic Products for the Determination of Heavy Metals

The sample preparation of a cosmetic specimen in Cosmetic Science for the purpose of determining the analytical composition of heavy and toxic metals such as lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As) is of particular importance due to the difficulty of handling the sample. There are two main methods of sample preparation. The first method is the wet digestion of the sample with strong acids such as H2SO4, HNO3, HF, and HNO3/HCl (1:3) and the combination of a strong acid with H2O2. Liquid digestion of the sample under the influence of strong acids damages the organic material of the sample and converts the carbon into carbon dioxide. The contained metals are oxidized to the highest oxidizing step and converted to soluble salts. A problem with this method is the loss of metals during digestion because it occurs at high temperatures as well as the decrease in the concentration of the residual acid. The second method of preparation is the wet liquid digestion of the sample with strong acids in a microwave oven in a closed vessel. The acids that are used are mainly HNO3 or mixtures of acids such as HNO3–HCl and HNO3–H2SO4. When the sample in the acid’s solvent is exposed to microwave energy, it can reach temperatures substantially above the boiling temperature of the acid solution. The result is the decomposition of the organic material, the oxidation of the metals, and their conversion to soluble nitrates. The advantages of using microwaves are the ability to control the temperature, pressure, and loss of metals and, thus, avoid erroneous measurement results. Simultaneously with the above, extraction methods have been, for almost a decade, very effective complementary processes that we can use to enrich a sample of a cosmetic product. Liquid–liquid dispersion micro-extraction (DLLME) and solid phase extraction (SPE) are the two main methods used in sample preparation and are usually applied after the digestion process.

Development and Validation of a Method for the Analysis of Zinc Oxide in Cosmetic Matrices by Flame Atomic Absorption Spectroscopy

A fast and simple method for the extraction and Flame Atomic Absorption Spectroscopy (FAAS) quantification of ZnO in different cosmetic matrices, including lipsticks, water-in-oil foundations, and oil-in-water creams, was developed and validated, according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) and the United States Pharmacopeial Convention guidelines. The sample preparation consisted of an ultrasound-assisted ethanolic extraction of ZnO followed by digestion with 1 M nitric acid (HNO₃). Samples were analyzed by Flame Atomic Absorption Spectroscopy (FAAS). Specificity, linearity, the limit of detection (LOD), the limit of quantification (LOQ), sensitivity, precision, and accuracy parameters were studied. The robustness of the method was evaluated with a five-variable Youden-Steiner model. The method was specific for ZnO, and the extraction procedure did not affect the stability of the signal compared to the background. The method was linear in the range 0.2-1.0 mg/L with LOD/LOQ values equal to 0.0156 (mg·L^-1)/0.0473 (mg·L^-1), 0.0098 (mg·L^-1)/0.0297 (mg·L^-1), 0.0113 (mg·L^-1)/0.0341 (mg·L^-1), and 0.0131 (mg·L^-1)/0.0397 (mg·L^-1), respectively, for raw material, lipstick, liquid foundation, and emulsion matrices. Regarding precision, the %RSD values were below 3.0% for repeatability and intermediate precision. Global reproducibility RSD was below 8.0% for all matrices. The percentage of recovery was not statistically different from 100% in all cases. The final concentration was found to be a critical variable for all matrices except for the raw material. The variables associated with the extraction step (ethanol volume, bath temperature, and extraction time) were critical in the extraction of liquid foundations and cream emulsions. The method reduces the number and concentration of mineral acids spent on the digestion of ZnO, and its application is extendable to raw materials. This development is an adequate tool for routine analysis and cosmetic quality control of chemically different products that contain ZnO as ultraviolet radiation (UV) filter, to guarantee regulatory compliance and ensure the safety and efficacy of products delivered to consumers.

ELISA and Chemiluminescent Enzyme Immunoassay for Sensitive and Specific Determination of Lead (II) in Water, Food and Feed Samples

Lead is a heavy metal with increasing public health concerns on its accumulation in the food chain and environment. Immunoassays for the quantitative measurement of environmental heavy metals offer numerous advantages over other traditional methods. ELISA and chemiluminescent enzyme immunoassay (CLEIA), based on the mAb we generated, were developed for the detection of lead (II). In total, 50% inhibitory concentrations (IC₅₀) of lead (II) were 9.4 ng/mL (ELISA) and 1.4 ng/mL (CLEIA); the limits of detection (LOD) were 0.7 ng/mL (ic-ELISA) and 0.1 ng/mL (ic-CLEIA), respectively. Cross-reactivities of the mAb toward other metal ions were less than 0.943%, indicating that the obtained mAb has high sensitivity and specificity. The recovery rates were 82.1%–108.3% (ic-ELISA) and 80.1%–98.8% (ic-CLEIA), respectively. The developed methods are feasible for the determination of trace lead (II) in various samples with high sensitivity, specificity, fastness, simplicity and accuracy.

Comparative study on the bioaccumulation of lead, cadmium and nickel and their toxic effects on the growth and enzyme defence strategies of a heavy metal accumulator, Hydrilla verticillata (L.f.) Royle

The current hydroponic experiment investigated differences in the uptake, physiological response and defence mechanisms of Hydrilla verticillata (L.f.) Royle in response to three representative toxic heavy metals. The results revealed the following: as an excellent heavy metal accumulator, H. verticillata showed an accumulation pattern of Ni > Cd > Pb within experimental scope. Fourteen days (Ni and Cd) and 21 days (Pb) were the time thresholds under the same heavy metal concentration toxicity, while 33.06 μM (Ni) and 40 μM (Cd and Pb) were the concentration thresholds under the same 21-day duration treatment, to accumulate the most amount of metals. Hence, Pb might be accumulated more if it expands the experimental duration and concentration, for it continuously increases throughout the experimental period. Reasons for these uptake differences are that plant physiological response, tolerance and resistance vary under different heavy metal stress. First, the biomass and protein content of H. verticillata were both the highest under Pb stress, indicating the plant largest tolerance to Pb stress. Second, the tolerance thresholds of three antioxidant enzymes (SOD, CAT and POD) were the highest under Pb stress. Third, the three antioxidant enzymes and two other related resistance-causing enzymes (PPO and PAL) revealed that plant resistance was strongest at low Cd concentrations (0-20 μM) and at high Pb stress levels (40 μM). Furthermore, CAT is the most important antioxidant enzyme to combat three metal stresses (average relevance: CAT(0.89) > POD(0.48) > SOD(0.42)), while PAL is more important than PPO (average relevance: PAL (0.77) > PPO(0.72)). In conclusion, Pb-polluted water is best treated with H. verticillata because of the latter's high uptake potential and strong defence capacity. These results provide an accurate, efficient and economical reference for phytoremediation. Graphical abstract.

Using PVA/CA/Au NPs electrospun nanofibers as a green nanosorbent to preconcentrate and determine Pb2+and Cu2+in rice samples, water sources and cosmetics

Polyvinyl alcohol (PVA)/citric acid (CA)/Au NPs electrospun nanofibers was synthesized and applied as a green and efficient sorbent to extract and preconcentrate Pb²⁺and Cu²⁺from water sources, rice samples and cosmetics before FAAS.

Facile synthesis of gold nanoparticles using carbon dots for electrochemical detection of neurotransmitter, dopamine in human serum and as a chemocatalyst for nitroaromatic reduction

Herein, the authors reported a carbon dots mediated synthesis of gold nanoparticles (AuNPs) at room temperature. Transmission electron microscopy revealed that the AuNPs are spherical in shape with a size of 10 nm. As-prepared AuNPs was immobilised on carbon paste electrode and subjected to electrochemical sensing of an important neurotransmitter dopamine. Differential pulse voltammetry studies revealed sensitive and selective determination of dopamine in the presence of commonly interfering ascorbic acid and uric acid. The linear detection range was 10-600 μM and the limit of detection was 0.7 ± 0.18 μM. The practical application was demonstrated by measuring dopamine in human blood serum and urine samples. The catalytic activity of AuNPs was evaluated by sodium borohydride mediated reduction of nitroaromatic compounds. The reduction kinetics was found to be pseudo-first-order kinetics. All the tested nitroaromatics reduced to corresponding amines in <10 min.

Determination of heavy metals (lead, cadmium, arsenic, and mercury) in authorized and unauthorized cosmetics

Aim: The present study evaluates lead, cadmium, arsenic, and mercury contamination in lipsticks, mascara, eye shadow, and eyebrow pencils, and compares the amounts of these toxic elements in both legal and contraband products. Background: The presence of heavy metals in cosmetics is of major concern, and requires constant monitoring to ensure the safety of consumers. Cosmetics contaminated with heavy metals can lead them to accumulate in the skin, while the further migration of these toxic elements to blood vessels can cause subsequent difficulties. Material and methods: The graphite Furnace Atomic Absorption Spectrometry (GFAAS) and Direct Mercury Analyzer (DMA) techniques were used. Results: The data indicate that the lead content in the products did not exceed the acceptable limit of the Federal Office of Consumer Protection and Food Safety of Germany (BVL), and that the cadmium values in all products were significantly lower than the limit set by the BVL. The arsenic contents of lipsticks, eye shadows, and eyebrow pencils was significantly higher than the BVL standard, while the mercury content was far below the BVL standards, so there seems to be no concern associated with this toxic element. Legal cosmetics showed better results, except for mascara, which had higher amounts of arsenic than contraband. The higher contents of arsenic in contraband eye shadows and eyebrow pencils is an issue that should be taken into considerations by the relevant authorities. Conclusion: The authors suggest further analysis of the toxic elements in cosmetics and better monitoring of both imported and contraband cosmetics. Moreover, consumers' knowledge of the potential risks of the frequent application of cosmetic products should be improved.

A systematic review of global legal regulations on the permissible level of heavy metals in cosmetics with particular emphasis on skin lightening products

BACKGROUND

There is an urgent need to address the safety problems caused by the use of skin lightening cosmetics. Evidence suggests that some of them may contain heavy metals.

OBJECTIVES

We conducted a systematic review of global legal regulations regarding the permissible level of mercury, lead, arsenic, and cadmium in cosmetic products, with particular emphasis on skin lightening preparations.

METHODS

The systematic search of documents was a two-stage process. First, official websites of 17 regional organizations and subsequently regulations for countries with a population over 100 million were searched.

RESULTS

Fifteen legislative acts, encompassing more than 67·2% of the global population were reviewed. Regulations were identified for 44/59 high income countries, 16/55 upper middle income countries, 9/45 lower income countries, 0/34 low income countries. The median adult literacy rate was 91·4% and 64·2% in countries with and without regulations, respectively. The use of mercury, lead, arsenic, and cadmium has been banned in 67, 67, 65, and 65 out of 69 countries, respectively.

CONCLUSIONS

While regulations exist in most of the high income countries, in low income countries there is a lack of similar standards. In most countries for which these legal regulations have been identified, restrictions on the permissible level of heavy metals are strict. There is a need for enforcement of existing rules, and rigorous assessment of the effectiveness of these regulations.