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Abstract

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.

Keywords

Health risk assessment skin lightening cosmetics hazard quotient toxic heavy metal Botswana

Introduction

Heavy metals in the environment such as lead (Pb), chromium (Cr), nickel (Ni) and arsenic (As) arise from both natural and anthropogenic sources.^1–3 The anthropogenic sources of these heavy metals have resulted in elevated levels of metal pollutants in the environment.^4,5 The pursuit of physical beauty by men and women has increased the use of cosmetics around the world.^6,7 In particular, the use of cosmetics products, especially skin lightening cosmetics has been found to be a common practice in Africa, Asia, Middle East and Latin America countries.⁸ In the early years of cosmetics use, it was assumed that these products worked only on the surface of the skin and would not be absorbed through the skin.⁶ However, studies later established that some of the additives in these products can have systemic absorption through the skin which raised concerns about their safety.⁶ The detrimental health effects of heavy metals Pb, Cr, As and Ni are well documented.^9,10 The adverse health effects from exposure to Pb are more prominent in children than adults with levels of Pb as low as 10 μg/dl in blood leading to damage of the brain, impaired vision and slowed growth.¹¹ In adults, the detrimental health effects of Pb include reproductive problems, decreased fertility and kidney dysfunction.¹ Studies such as the one carried out in Italy were able to establish a link between children’s makeup containing heavy metals such as Ni and Cr and skin irritation.¹² Several studies have linked dermatitis and allergic reactions to the use of cosmetic products such as children’s bath products, facial care products and body care products.^13,14 In addition, the disposal of these products is not regulated and in most cases products are washed down the drain which has the potential to contaminate ground water.¹⁰ This has culminated into more studies to ascertain for the safety of these products, stringent regulations governing product quality and user protection. For example, in 1976, the European Union (EU) laws for cosmetics banned the use of Pb and its compounds in cosmetic products since 1976.¹⁵ Furthermore, the United States Food and Drug Administration (US FDA) through the Federal Food, Drug and Cosmetic Act (FD&C Act) frequently carries out product sampling for examination and analysis which assesses the plant and import compliances to safety standards.¹⁶ It is important to note that cosmetic products are regulated by the US FDA before their release into the mainstream market and this task has been relegated to manufacturers who are required to assess the safety of their products before reaching consumers.¹⁷

However, several developing countries such as Botswana, Zimbabwe, Lesotho and Swaziland lack legislations that regulate the import, distribution and use of cosmetics products in line with standards that are commensurate with those set up by the US FDA and EU.^18–20 Studies have recommended that in the absence of laws regulating levels of toxic metals in cosmetic products, a concept called ‘Threshold of Toxicological Concern’ (TTC) be used for the evaluation of the safety of cosmetic ingredients.^21,22 TTC considers the chemical structure and toxicity information of compounds that are related in structure.²¹ It compares the approximated oral intake of a particular compound with the TTC value obtained from toxicity data of similar compounds.

Currently, there is no regulation in Botswana governing quality checks and controls for determination of metals in cosmetic products imported into the country. This is the first study to be carried out in Botswana to ascertain the presence of toxic heavy metals in cosmetic products imported and sold in Botswana. The objective of this study, therefore, is to assess the presence of various trace metals such as as Pb, Cr, Ni and As in cosmetic products sold in Botswana market. Due to their detrimental health effects even at low concentrations (for example; 10 μg/dl of Pb in blood), these trace metals have been listed in the EU Cosmetics Directive in the class of compounds that have been banned for use in cosmetics.²³ This study intends to raise awareness on the prevalence of toxic metals in cosmetic products and the risks associated with the use of such products. Lastly, the study will also provide baseline data for further studies on epidemiological patterns and determinants of skin related problems in Botswana.

Materials and methods

Sampling location and sample collection

The cosmetic products were facial and body creams and lotions purchased from different beauty shops in Gaborone, Botswana. A total of 14 skin lightening cosmetic samples were used in the study (Figure 1). Unfortunately, the labelling on the products did not indicate the active ingredients responsible for bleaching of the skin. The cosmetic products were chosen based on their frequency of purchase by users from the stores as per the store assistants and therefore their resultant popularity among users. The shop assistants were asked verbally about cosmetic products that consumers frequently purchased and based on that information, products that are popular with the consumers were bought and used in the study. During sampling, information about the manufacturers, product name, brand, colour and the product’s ingredients on the label were all recorded. The products used in this study originated from Hong Kong (3), China (4), Italy (2), South Africa (2), Switzerland (1), Spain (1) and Democratic Republic of Congo (DRC) (1). The samples were analysed for heavy metals Pb, Cr, Ni and As.

Figure 1.

Skin lightening products used in the study.

Reagents and chemicals

All reagents, solvents and chemicals used in this study were of analytical grade. Hydrochloric acid (35%, v/v), nitric acid (65%, v/v) and hydrofluoric acid (40%, v/v) were all supplied by LabChem (Johannesburg, South Africa). Stock standard solutions of Pb, Cr, Ni and As (1000 mg/l) were also purchased from Sigma Aldrich (St Louis, USA). Double deionized water was produced from the chemistry lab and was used for dilution of samples prior to analysis using inductively coupled plasma optical emission spectrometry (ICP-OES; Perkin Elmer, Optima 7300DV).

Sample preparation and chemical analysis

Exactly 1.0 g of each sample was weighed accurately into a Teflon microwave digestion vessel. About 10 mL of a mixture of nitric acid (65%, v/v) and hydrofluoric acid in the ratio of 4:1 was added to the samples. The Teflon vessel was capped and swirled to thoroughly mix the sample with the acid. This was followed by wet digestion of the sample at 200°C for 15 min in a microwave digestion system (Microwave Reaction system MARS 6, CEM corporation, USA). The solution was then allowed to cool to room temperature, filtered using Whatman no. 42 into a 100 mL volumetric flask and diluted to the mark with deionized water. The precision and accuracy of the method were determined by analysis of procedural blanks, calibration standards and triplicate of samples. The sample solution was analysed for Pb, Cr, Ni and As using ICP-OES.

Health risk assessment

Heavy metals contained in cosmetic products may enter the body through absorption through the skin. The dermal absorption of these heavy metals such as Pb is promoted by the presence of fat-soluble components in the products resulting in absorption of Pb through the skin as organo-Pb.²⁴ However, some of the heavy metals such as Cr are water-soluble which makes it easier for them to be absorbed through the skin.^25,26 The health risk assessment was evaluated using the average daily intake for exposure dose through dermal contact (ADI_D) and hazard quotient (HQ) based on the concentrations of heavy metals detected in cosmetic products.^27,28 The ADI_D was estimated for all samples using equation (1)

{AD}_{ID} (mg / day) = \frac{C \times SA \times AF \times ABS \times EF \times ED}{BW \times AT}

(1)

Where C (mg/kg) is the measured concentration of the analyte of interest, SA (cm²) is the exposed skin area given as 565 cm² for skin lightening creams and lotions, AF (mg/cm²/day) is the adherence factor which is given as 0.07 for leave on cosmetics, ABS is the dermal absorption factor (ABS ∼0.001 for Pb, Cr, Ni and As), EF (day/year) is the frequency of the exposure which is taken as 350 days/year, ED (year) is the exposure duration which is averaged to 30 years, BW (kg) is the body weight of a human being (taken as 70 kg) and AT (day) is the averaging time (10,950 days).^28,29

On the other hand, the hazard quotient assesses whether there are potential adverse health effects emanating from exposure to cosmetic products.²⁸ The hazard quotient of the different metals in samples was evaluated as the ratio between the average daily intake for exposure dose through dermal contact (ADI_D) and the reference dermal dose (Rfd_dermal) using equation (2).³⁰ A hazard quotient of less than one is considered to be associated with no adverse effects

HQ = \frac{{ADI}_{D}}{{RfD}_{dermal}}

(2)

The Rf_D (mg/kg day) values for Pb, Cr, Ni and As were 1.4 × 10⁻⁴, 1.5, 2.0 × 10⁻² and 3.0 × 10⁻⁴ respectively.^28,31 The oral reference dose is the estimated daily human exposure to metals that has no hazardous effect during lifetime. The hazard index (HI) from all metals studied was estimated from the summation of the HQ of individual metals using equation (3)

HI = {HQ}_{Pb} {+ HQ}_{As} {+ HQ}_{Cr} {+ HQ}_{Ni}

(3)

Quality control

Glassware was washed with soap and tap water and then rinsed many times with tap water before being soaked overnight in 5% HNO₃ solution. They were subsequently rinsed with double distilled water and dried in oven at 70°C. Before each sample was analysed, three blank runs were carried out and the average blank measurement was subtracted from the sample measurement. Samples measurements were taken in triplicates. Due to lack of a cosmetic certified reference material, the accuracy and precision of the analytical methods employed were validated through the spike recovery procedure. This was done by introducing into fresh portions of analysed samples a known concentration of the analysed element and percent recovery for each element addressed the accuracy of the analytical procedure. The percent recoveries (R) were calculated using equation (4);

R = \frac{amount after spike - amount before spike}{amount added} \times 100 %

(4)

The limit of detection (LOD) and limit of quantification (LOQ) were determined experimentally from 3s/m and 10s/m respectively where s is the standard deviation of the signal measure of the blank solutions and m is the slope of the calibration curve for the specific test metal.³² Intra and inter-day precisions were also carried out using a 5 mg/kg multi-element standard solution following the optimized analytical procedure used for analysis of the cosmetic samples. For intra-day precision, 5 mg/kg multi-elemental standard solution was analysed under optimized conditions for five times twice in a day and response concentrations were recorded. For inter-day precision, 5 mg/kg multi-elemental standard solution was analysed five times for three consecutive days under optimized conditions and the response concentrations were recorded. The calculated %RSD values for both inter-day and intra-day were less than 2% indicating that the data set are closer to each other.

The accuracy of the analytical procedure used was demonstrated by assessing the amounts of target metals after spiking the cosmetic samples with known concentrations of Pb, As, Cr and Ni. The average percent recoveries of Pb, As, Cr and Ni in the spiked samples were determined to be 96.3 ± 2.8, 105.2 ± 6.1, 104.6 ± 3.9 and 96.7 ± 2.3% respectively (Table 1). The accuracy results indicate excellent efficiency of the analytical procedure used. The LOD determined were 0.0256, 0.0932, 0.0015 and 0.0063 mg/kg for Pb, As, Cr and Ni respectively. The LOD results obtained are similar to those found in related studies carried out elsewhere.^9,33 In a study by Alqadami et al. (2017), LODs for Pb and As in skin lightening creams were found to be 0.0038 and 0.0046 mg/kg respectively.⁹ The LOQ values for Pb, As, Cr and Ni were found to be 0.0853, 0.3105, 0.0050 and 0.0209 mg/kg respectively. The LOQ results obtained were similar to those achieved in other related studies.²⁵ The calculated %RSD values for both inter-day and intra-day were less than 2% indicating high precision of the data sets. The correlation coefficients (R²) were in the range of 0.964–0.984 which indicates good linearity for all metals in the concentration ranges investigated. Therefore, the proposed method demonstrates good applicability for determination of Pb, As, Cr and Ni in cosmetic products.

Table 1.

Linear range, correlation coefficient, percent recoveries, limit of detection and limit of quantification data for the four metals investigated.

Metal	R ²	Recovery (%)	LOD (mg/kg)	LOQ (mg/kg)
Pb	0.984	96.3 ± 2.8	0.026	0.085
As	0.981	105.2 ± 6.1	0.093	0.311
Cr	0.964	104.6 ± 3.9	0.002	0.005
Ni	0.983	96.7 ± 2.3	0.006	0.021

Results and discussion

Total metal concentration in cosmetic products

Total concentrations of Pb, Cr, Ni and As found in the 14 cosmetic products were analysed using ICP-OES and the results are presented in Table 2. All four metals investigated in 14 cosmetic samples were detected in all samples in varying concentrations. All 14 cosmetic products analysed were found to contain the highest concentration of Pb followed by Ni, Cr and As. Pb concentrations were in the range of 45.75–193.60 mg/kg followed by those of Ni, Cr and As in the range 2.99–9.50; 3.32–7.41 and 1.95–4.52 mg/kg respectively. The highest concentrations of Pb were determined in the S8 (193.60 ± 3.58 mg/kg) and S14 (144.45 ± 1.78 mg/kg) skin lightening cosmetics originating from Guangzhou. The results obtained for Pb and As are comparable to those of a previous study in which concentrations of Pb and As in skin lightening cosmetics reached highs of 143 and 12.30 mg/kg respectively.⁹

Table 2.

Mineral elements detected in cosmetic samples.

Sample	[Metal]/(mg/kg)^a
Sample	Pb	As	Cr	Ni
S1	105.60 ± 1.22	3.83 ± 0.17	7.41 ± 0.14	6.16 ± 0.07
S2	134.75 ± 1.34	4.23 ± 0.30	5.49 ± 0.08	7.65 ± 0.02
S3	115.80 ± 2.50	2.51 ± 0.76	4.47 ± 0.08	5.90 ± 0.19
S4	117.55 ± 1.29	4.52 ± 0.22	5.91 ± 0.18	8.33 ± 0.05
S5	121.30 ± 3.09	1.95 ± 0.23	4.45 ± 0.12	6.93 ± 0.15
S6	126.70 ± 2.32	4.29 ± 0.44	5.64 ± 0.10	6.84 ± 0.20
S7	144.45 ± 1.78	2.85 ± 0.28	4.86 ± 0.16	7.28 ± 0.16
S8	193.60 ± 3.58	2.16 ± 0.73	7.22 ± 0.07	9.50 ± 0.45
S9	82.90 ± 1.23	2.48 ± 0.43	3.32 ± 0.05	4.14 ± 0.23
S10	64.35 ± 2.05	3.04 ± 0.21	4.24 ± 0.17	4.75 ± 0.09
S11	47.65 ± 0.96	3.85 ± 0.44	4.80 ± 0.04	3.71 ± 0.05
S12	92.35 ± 1.89	2.75 ± 0.40	4.11 ± 0.09	4.91 ± 0.09
S13	45.75 ± 0.10	2.66 ± 0.30	3.72 ± 0.01	2.99 ± 0.09
S14	148.95 ± 1.97	3.13 ± 0.09	4.26 ± 0.04	7.22 ± 0.22

^aThis is total concentration of all oxidation states of metal ions present in the sample.

There are currently no regulations in Botswana governing maximum contaminants limits for contaminants such as metal ions in cosmetic products. Regulatory agencies such as the FDA have set maximum contaminant limits for contaminants and impurities in some color additives used in cosmetics. For example, contaminant limits have been set for Pb and As to 10 and 3 mg/kg respectively and for Ni and Cr to 5 mg/kg in colour additives that are subject to certification and are allowed for use in foods, drugs, cosmetics and medical devices. In the absence of Botswana’s regulations for maximum contaminant limits of metals in cosmetic products, the results obtained in this study were interpreted based on the FDA regulations stated above. Applying these set limits, this means that the total concentration of Pb in all 14 sampled analysed significantly exceeded the maximum contaminant limit of 10 mg/kg for Pb in cosmetics.³⁴ In some samples the concentration of Pb was more than 15 to 20 times above the set limit. Similarly, S8 was found to contain the highest concentration of Ni (9.50 ± 0.45 mg/kg). Only five out of the 14 cosmetic samples studied contained concentration of Ni above the set maximum contaminant limit of 5 mg/kg.³⁵ The largest concentration of Cr was determined in the S1 (7.41 ± 0.14 mg/kg) sample that also originated from Guangzhou. Out of the 14 samples analysed for Cr, nine were found to contain Cr above the set maximum contaminant limit of 5 mg/kg.³⁵ On the other hand, the highest concentration of As (4.52 ± 0.22 mg/kg) was found in the S4 sample that has been imported from Italy. Only six out of the 14 products analysed contained As above the set limit of 3 mg/kg.³⁴ The high concentrations of metals in the skin lightening products should sound an alarm for the users because of the adverse health effects of these metals. It is also noteworthy that the metals found in cosmetic products are classified as unintentional contaminants and seen as impurities in the products and therefore it is not a requirement that should be listed on the product labels.⁹ These metal impurities come about either as a byproduct of the manufacturing process or contamination arising from raw materials used in the production of cosmetics.⁹ Heavy metals such as Pb, As, Cr and Ni are naturally occurring in the environment and their sources include soils, rocks, water and organic matter and are bound to be present in raw materials used in the manufacture of various products including cosmetics. As mentioned earlier, the quality and authenticity of cosmetic products has been relegated to the manufacturers to remove the impurities and toxic ingredients from the products before they reach consumers. However, only few manufacturers such as those in Canada heed this advice from governments and remove impurities from the final product.³⁶ In some instances, some manufacturers may not even be aware that their products are contaminated with such metals because of lack of manufacturer testing and regulatory oversight.

Health risk assessment of tested cosmetic products

The health risks presented by exposure to heavy metals such as Pb, As, Cr and Ni were evaluated using ADI_D, HQ and HI. It is critical that the adverse effects of these heavy metals on human health should be taken seriously because of the daily application of these products on the face and their contact with vital body organs such as eyes, mouth, nose and ears that may serve as passageways through which such toxic metals are absorbed into the body.³⁷ Some of these heavy metals such as Pb have been found to be detrimental to human health even at low concentrations (10 μg/dl) in the blood.¹¹ For example, low concentrations of Pb can act as a selective blocker of voltage-dependent calcium channels and can also decrease re-absorption of small organic molecules on renal mitochondria.²⁷

The health risk assessment of the cosmetic products investigated are presented in Table 3. HQ values of greater than one corresponding to Pb were calculated for all 14 products which indicated potential adverse health effects to users of the products. As stated by the United States Environmental Protection Agency (USEPA), HQ should not be interpreted for probability that an adverse health effect will arise, and it should not be construed to be proportional to risk either, but it is however, evidence for potential existence of adverse health effects.^28,38 The facial cosmetic product, S8, revealed the highest HQ (∼749.2) compared to all other products analysed. These results corroborate the findings obtained regarding total concentration of Pb in sample S8 (193.60 ± 3.58 mg/kg) which contained the highest concentration of Pb compared to other samples investigated. Similarly, S13 demonstrated the lowest HQ (∼177.0) for Pb compared to other products. However, HQ ∼ 177.0 still indicates serious potential adverse health effects to human beings. The values of ADI_D for Pb in all cosmetic products investigated exceeded the recommended reference dose of 1 × 10⁻⁴ mg/kg. day (2.5 × 10⁻²–1.05 × 10⁻¹ mg/kg. day).^25,39 In some cases, for example, the S8 sample posed ADI_D value for Pb that is 1050 times greater than the recommended reference dose. It is also important to note that the HQ values were greater than one for As in all of the 14 samples analysed (3.52–8.16). The high and low HQ values for As also corresponded well with the HQ values for As in the cosmetic products investigated. These findings reveal appreciable risk from As to the health of consumers. In contrast, the HQ values for Cr and Ni were less than 1. This demonstrated low risk to consumers from these metals contained in the cosmetic products. However, it is noteworthy that the cumulative risk to consumers due to exposure to Cr and Ni arising from repeated use of the products cannot be overemphasized. It was also found that the HI values for the metals investigated exceeded 1. The high HI values corroborate the findings of total heavy metal content in the cosmetic products investigated and the high HQs. The high HI values demonstrated that the potential health risk from toxic Pb is quite significant. The results obtained in this study show a similar trend to those reported in the literature for related studies.^25,28,40,41 In a study by Rusmandi et al. (2017), respective HQ values of 0.016–0.025 and 0.587–1.587 for Ni and Pb were determined in skin lightening cosmetics.²⁸ In another study, HQ values for Pb in cosmetics reached highs of 45.23.²⁵

Table 3.

Health risk assessment of cosmetic product.

	Health risk assessment								HI
	Pb		As		Cr		Ni
Sample	ADI_D (mg/kg.day)	HQ	ADI_D (mg/kg.day)	HQ	ADI_D (mg/kg.day)	HQ	ADI_D (mg/kg.day)	HQ
S1	5.7 × 10⁻²	408.7	2.08 × 10⁻³	6.92	4.01 × 10⁻³	2.68 × 10⁻³	3.34 × 10⁻³	0.167	415.7
S2	7.3 × 10⁻²	521.5	2.29 × 10⁻³	7.64	2.97 × 10⁻³	1.98 × 10⁻³	4.14 × 10⁻³	0.207	529.3
S3	6.3 × 10⁻²	448.1	1.36 × 10⁻³	4.53	2.42 × 10⁻³	1.61 × 10⁻³	3.20 × 10⁻³	0.160	452.8
S4	6.4 × 10⁻²	454.9	2.45 × 10⁻³	8.16	3.20 × 10⁻³	2.13 × 10⁻³	4.51 × 10⁻³	0.226	463.3
S5	6.6 × 10⁻²	469.4	1.06 × 10⁻³	3.52	2.41 × 10⁻³	1.61 × 10⁻³	3.75 × 10⁻³	0.188	473.1
S6	6.9 × 10⁻²	490.3	2.32 × 10⁻³	7.75	3.06 × 10⁻³	2.04 × 10⁻³	3.71 × 10⁻³	0.185	498.2
S7	7.8 × 10⁻²	559.0	1.54 × 10⁻³	5.15	2.63 × 10⁻³	1.76 × 10⁻³	3.94 × 10⁻³	0.197	564.3
S8	1.05 × 10⁻¹	749.2	1.17 × 10⁻³	3.90	3.91 × 10⁻³	2.61 × 10⁻³	5.15 × 10⁻³	0.257	753.4
S9	4.5 × 10⁻²	320.8	1.34 × 10⁻³	4.48	1.80 × 10⁻³	1.20 × 10⁻³	2.24 × 10⁻³	0.112	325.4
S10	3.5 × 10⁻²	249.0	1.65 × 10⁻³	5.49	2.30 × 10⁻³	1.53 × 10⁻³	2.57 × 10⁻³	0.129	254.6
S11	2.6 × 10⁻²	184.2	2.09 × 10⁻³	6.95	2.60 × 10⁻³	1.73 × 10⁻³	2.01 × 10⁻³	0.101	191.3
S12	5.0 × 10⁻²	357.4	1.49 × 10⁻³	4.97	2.23 × 10⁻³	1.48 × 10⁻³	2.66 × 10⁻³	0.133	362.5
S13	2.5 × 10⁻²	177.0	1.44 × 10⁻³	4.80	2.02 × 10⁻³	1.34 × 10⁻³	1.62 × 10⁻³	0.081	181.9
S14	8.1 × 10⁻²	576.4	1.70 × 10⁻³	5.65	2.31 × 10⁻³	1.54 × 10⁻³	3.91 × 10⁻³	0.196	582.3

Note. ADI_D: average daily intake for exposure dose through dermal contact; HI: hazard index; HQ: hazard quotient.

Conclusion

This study demonstrates ICP-OES analysis of Pb, Cr, As and Ni in skin lightening cosmetics with excellent recoveries ranging from 96.3–105.2% which indicates reproducibility and reliability of the analytical procedure. Total metal concentration for Pb in all 14 skin lightening cosmetics examined far exceeded the set maximum contaminant level as per the USFDA. Total concentrations of Cr, As and Ni were higher than the set maximum contaminant limits in 9, six and five of the 14 samples examined respectively. The hazard quotients for Pb in all 14 cosmetic samples were greater than 1, an indication of potential adverse health effects from Pb in all products analysed. Furthermore, the daily dermal exposure and average daily intake for Pb in all 14 samples both exceeded the reference daily doses. Thus, health risk assessment results emanating from hazard quotient, daily dermal exposure, average daily intake and health risk index for Cr, As, and Ni indicate potential risk to human health. It is important that the health risk assessment of the metals under study was estimated based on total concentration of all metal ion species present in the samples and specification of individual metal ions was not taken into consideration. This might have inflated the health risks of the metals investigated. This presents a weakness for this study and therefore, future studies should focus on the various species of these metal ions present in cosmetic products to better understand their topical and potential transdermal absorption. These findings indicate that facial skin lightening cosmetics imported into the country are likely to have harmful health effects to consumers. This, therefore, calls for strict regulatory guidelines on heavy metals in skin lightening cosmetics imported into Botswana. Furthermore, there are currently no regulations in Botswana governing maximum contaminants limits for contaminants such as metal ions in cosmetic products. One of the strengths of this study include public awareness of toxic heavy metals in skin lightening cosmetics needs to be raised and consumers need to be educated on the potential adverse human health effects from topical exposure to heavy metals. Lastly, strategic partnership with neighbouring countries such as South Africa that have well laid out regulations on the importation and distribution of cosmetic products could go a long way in assisting Botswana combat the importation of these products in the country.

Footnotes

Acknowledgements

The authors would like to thank Botswana International University of Science and Technology (BIUST) for wholly sponsoring this study.

Author contributions

PD: Conceptualisation; methodology; student supervision; manuscript writing; data analysis. OM: Data collection; data analysis; writing – initial draft. TTK: Data analysis; manuscript reviewing. RK: Methodology; validation; manuscript revisions. All authors have read and agreed to the published version of the manuscript.

Declaration of conflicting interests

The authors report no potential conflict of interest regarding research, authorship and publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research work was wholly financially supported by the Botswana International University of Science and Technology (BIUST), Research Initiation Grant Number BIUST/ds/R&I/26/2016.

Ethical approval

Not applicable

Informed consent

Not applicable

Availability of data

Not applicable

ORCID iD

Pogisego Dinake

References

Kelebemang

Dinake

Sehube

, et al. Speciation and mobility of lead in shooting range soils. Chemical Speciation and Bioavailability 2017; 29: 143–152.

Türkdoğan

Kilicel

Kara

, et al. Heavy metals in soil, vegetables and fruits in the endemic upper gastrointestinal cancer region of Turkey. Environmental Toxicology and Pharmacology 2003; 13(3): 175–179.

Rovira

Nadal

Schuhmacher

, et al. Human exposure to trace elements through the skin by direct contact with clothing: Risk assessment. Environmental Research 2015; 140: 308–316.

Mari

Ferré-Huguet

Nadal

, et al. Temporal trends in metal concentrations in soils and herbage collected near a municipal waste incinerator: Human health risks. Human and Ecological Risk Assessment: An International Journal 2007; 13: 457–472.

Nadal

Schuhmacher

Domingo

. Metal pollution of soils and vegetation in an area with petrochemical industry. Science of The Total Environment 2004; 321: 59–69.

de Paula

CER

Cruz

GFB

Rezende

CMSP

, et al. Determination of Cr and Mn in moisturizing creams by graphite furnace atomic absorption spectrometry through direct introduction of the samples in the form of emulsions. Microchemical Journal 2016; 127: 1–6.

Orisakwe

Otaraku

. Metal concentrations in cosmetics commonly used in Nigeria. The Scientific World Journal 2013; 2013: 959637.

Salama

. Assessment of metals in cosmetics commonly used in Saudi Arabia. Environmental Monitoring and Assessment 2015; 188(10): 553.

Alqadami

Naushad

Abulhassan Abdalla

, et al. Determination of heavy metals in skin‐whitening cosmetics using microwave digestion and inductively coupled plasma atomic emission spectrometry. IET Nanobiotechnology 2017; 11: 597–603.

10.

Ayenimo

Yusuf

Adekunle

, et al. Heavy metal exposure from personal care products. Bulletin of Environmental Contamination and Toxicology 2010; 84: 8–14.

11.

Nourmoradi

Foroghi

Farhadkhani

, et al. Assessment of lead and cadmium levels in frequently used cosmetic products in Iran. Journal of Environmental and Public Health 2013; 2013: 962727–962735.

12.

Corazza

Baldo

Pagnoni

, et al. Measurement of nickel, cobalt and chromium in toy make-up by atomic absorption spectroscopy. Acta Dermato-Venereologica 2009; 89(2): 130–133.

13.

Campaign for Safe Cosmetics . No more toxic tub, 2009, pp. 1–28, http://www.safecosmetics.org.

14.

Zirwas

Moennich

. Shampoos. Dermatitis 2009; 20(2): 106–110.

15.

Council Directive of 27 July 1976 on the approximation of the laws of the Member States relating to cosmetic products (76/768/EEC). OJEC L 26227.9. 1976, p. 169.

16.

US FDA, United States Food and Drug Authorities Guidance for Industry . Center for food safety and applied nutrition (CFSAN). FDA Authority over Cosmetics, 2005.

17.

Al-Saleh

Al-Enazi

Shinwari

. Assessment of lead in cosmetic products. Regulatory Toxicology and Pharmacology 2009; 54: 105–113.

18.

Kachambwa

Naravage

James

, et al. The impacts of neo-liberalism on public health: A case study of skin bleaching among women living in Zimbabwe. Medical Journal of Zambia 2019; 46(3): 186–191.

19.

FDA-Issued/Supported export certificates for foods; US FDA, United States food and drug authorities. Center for food safety and applied nutrition (CFSAN), Office of Cosmetics and Colors. Imported Cosmetics, 2006.

20.

US FDA, United States Food and Drug Authorities . Center for Food Safety and Applied Nutrition (CFSAN), 2002.

21.

Kroes

Renwick

Feron

, et al. Application of the threshold of toxicological concern (TTC) to the safety evaluation of cosmetic ingredients. Food and Chemical Toxicology 2007; 45: 2533–2562.

22.

Williams

Rothe

Barrett

, et al. Assessing the safety of cosmetic chemicals: Consideration of a flux decision tree to predict dermally delivered systemic dose for comparison with oral TTC (Threshold of Toxicological Concern). Regulatory Toxicology and Pharmacology 2016; 76: 174–186.

23.

European Union’s cosmetics ingredients and substance annex II: list of substances which must not form part of the composition of cosmetic products. 2010.

24.

Ashraf

Taneez

Kalsoom

, et al. Experimental calculations of metals content in skin-whitening creams and theoretical investigation for their biological effect against tyrosinase enzyme. Biological Trace Element Research 2021; 199: 3562–3569.

25.

Nkansah

Owusu-Afriyie

Opoku

. Determination of lead and cadmium contents in lipstick and their potential health risks to consumers. J Consum Protect Food Safet 2018; 73: 191–198.

26.

Sainio

Jolanki

Hakala

, et al. Metals and arsenic in eye shadows. Contact Dermatitis 2000; 42: 5–10.

27.

Aryal

Bashyal

Gautam

, et al. Evaluation of lead and cadmium levels in lipsticks sold in Kathmandu, Nepal, and their potential health risk assessment. International Journal of Applied Sciences and Biotechnology 2021; 9(3): 213–219.

28.

Ismail

RusmadiRusmadi

Praveena

. A case study of selected heavy metals (lead, cadmium, and nickel) in skin-lightening creams and dermal health risk in Malaysia. Annals of Tropical Medicine and Public Health 2017; 10: 95–100.

29.

USEPA . Risk assessment guidance for Superfund volume I: human health evaluation manual (Part A). Washington, D. C.United States: Environmental Protection Agency, 1989. EPA/540/1–89/002.

30.

Tannenbaum

Johnson

Bazar

. Application of the hazard quotient method in remedial decisions: A comparison of human and ecological risk assessments. Human and Ecological Risk Assessment: An International Journal 2003; 9(1): 387–401.

31.

Koniecki

Wang

Moody

, et al. Phthalates in cosmetic and personal care products: Concentrations and possible dermal exposure. Environmental Research 2011; 111: 329–336.

32.

Armbruster

Pry

. Limit of blank, limit of detection and limit of quantitation. The Clinical Biochemist. Reviews 2008; 29 Suppl 1: S49–S52.

33.

Al-Saleh

Al-Enazi

. Trace metals in lipsticks. Toxicological and Environmental Chemistry 2011; 93(6): 1149–1165.

34.

Al-Dayel

Hefne

Al-Ajyan

. Human exposure to heavy metals from cosmetics. Orient J Chem 2011; 27(1): 01–11.

35.

Al-Qutob

Alatrash

Abol-Ola

. Determination of different heavy metals concentrations in cosmetics purchased from the Palestinian markets by ICP/MS. AES Bioflux 2013; 5(3): 287–293.

36.

Environmental Defence Canada . Heavy Metal Hazard – the health risks of hidden heavy metals in face makeup, 2011, pp. 1–39, https://environmentaldefence.ca/wp-content/uploads/2016/01/HeavyMetalHazard-FINAL.pdf.

37.

Alhussaini

HMA

Hossain

Arputhanantham

. Determination of toxic heavy metal content in a whitening creams by using inductively coupled plasma-optical emission spectrometry. Arabian Journal of Geosciences 2022; 15: 692.

38.

Colorado Department of Public Health and Environment Working Draft . Garfield county air toxics inhalation: screening level human, health risk assessment. Colorado Department of Public Health and Environment Disease Control and Environmental Epidemiology Division: Colorado, 2007.

39.

Scientific Committee on Consumer Safety . SCCS the SCCS's notes of guidance for the testing of cosmetic substances and their safety evaluation. 8th Revision, 2012.

40.

Akhtar

Kazi

Afridi

, et al. Human exposure to toxic elements through facial cosmetic products: Dermal risk assessment. Regulatory Toxicology and Pharmacology 2022; 131: 105145.

41.

Marinovich

Boraso

Testai

, et al. Metals in cosmetics: An a posteriori safety evaluation. Regulatory Toxicology and Pharmacology 2014; 69: 416–424.

Assessment of level of heavy metals in cosmetics

Abstract

Keywords

Introduction

Materials and methods

Sampling location and sample collection

Reagents and chemicals

Sample preparation and chemical analysis

Health risk assessment

Quality control

Results and discussion

Total metal concentration in cosmetic products

Health risk assessment of tested cosmetic products

Conclusion

Footnotes

Acknowledgements

Author contributions

Declaration of conflicting interests

Funding

Ethical approval

Informed consent

Availability of data

ORCID iD

References