Evaluation of toxic and essential metal content in selected children's, adult, and herbal toothpastes available in Turkiye: a cross-sectional analytical study

Summary

This cross-sectional analytical study quantified ten metals (aluminum, chromium, iron, nickel, copper, zinc, total arsenic, cadmium, total mercury, lead) by ICP-MS in 15 commercially available toothpastes purchased in Turkiye, covering children’s (n=8), adult (n=5), and herbal/natural (n=2 of the adult group, with overlap in classification) formulations. Mercury and total arsenic were below detection limits in all fifteen samples. Cadmium and lead were detected at low concentrations in a subset of samples and remained below internationally recognised safety limits (FDA 20 ppm lead (Pb), EU 0.5 ppm Pb; FDA 1 ppm cadmium (Cd); Turkish Cosmetics Regulation 1 ppm Pb and 0.1 ppm Cd). The study found no statistically significant differences in metal concentrations between children’s and adult toothpastes or between natural/herbal and conventional formulations (p > 0.05 for all comparisons except chromium). Toothpastes manufactured in Turkiye had significantly higher median chromium concentrations than imported products (p = 0.028). A screening-level health risk assessment calculated estimated average daily doses (ADD) and hazard quotients (HQ) for lead and cadmium; all HQ values were below 1.0 for both children and adults under typical and upper-bound use conditions.

Key numbers

Sampling: 15 toothpastes purchased from retail markets across Turkiye. Classification: S1-S8 children’s (8 samples; 5 herbal/natural, 3 conventional; 5 imported, 3 manufactured in Turkiye); S9-S15 adult (7 samples; 2 herbal/natural, 5 conventional; 1 imported, 6 manufactured in Turkiye). Analysis performed in triplicate by ICP-MS (radiofrequency power 1550 W; 0.96 L/min nebuliser gas; 0.88 L/min plasma gas; 3.01 bar nebuliser pressure; 0.01 ms dwell time; 3.7 degrees C spray chamber). CRM: TUBITAK UME CRM 1201 (trace elements in spring water); external QC performed without internal standard addition.

Essential metal concentrations (ICP-MS, mean ppm; Table 5, pp. 4-5):

Toxic metal concentrations (ICP-MS, mean ppm; Table 6, p. 5):

• Total arsenic: below LOD in all 15 samples (LOD not given in instrument output for As).
• Total mercury: below LOD in all 15 samples.
• Cadmium: detected in 5 samples. Range across detected samples: 0.00096 (S1, S3) to 0.00578 ppm (S6). All remaining 10 samples N.D. LOD 8.350 x 10^-4 ppm; LOQ 2.760 x 10^-3 ppm (Table 3).
• Lead: detected in 9 samples. Range across detected samples: 0.00583 (S1) to 0.12421 ppm (S6). All remaining 6 samples N.D. LOD 3.356 x 10^-4 ppm; LOQ 1.107 x 10^-3 ppm (Table 3). The highest Pb concentration (S6, 0.12421 ppm; a herbal children’s toothpaste manufactured in Turkiye) is 1.72 times the EU 0.5 ppm limit on a basis-adjusted comparison — note: the paper does not report Pb in the same basis as the EU limit and the comparison is basis-dependent; see Verification notes.

Maximum permissible concentrations cited by the source (Table 4, p. 4):

Health risk assessment (Table 7, p. 6): estimated average daily doses (ADD, micrograms/day) and hazard quotients (HQ) for lead and cadmium. Children: ingestion rate 0.30 g/brushing, 2 brushings/day. Adults: 0.04 g/brushing, 2 brushings/day. Health guidance values: HGV Pb 0.5 micrograms/day (child), 4.1 micrograms/day (adult), from OEHHA maximum allowable dose levels (MADLs). HGV Cd 1 microgram/day (child) per OEHHA.

Selected HQ values from Table 7:

• Highest child Pb HQ: 0.149 (S6; Pb 0.12421 ppm); well below 1.0.
• Highest child Cd HQ: 0.085 (S6; Cd 0.00578 ppm); well below 1.0.
• Highest adult Pb HQ: 0.020 (S6); well below 1.0.
• Highest adult Cd HQ: 0.0046 (S6); well below 1.0.

Statistical analysis: Mann-Whitney U for non-parametric group comparisons. No statistically significant differences in metal concentrations between children’s vs. adult, domestic vs. imported, or natural/herbal vs. conventional for any element (p > 0.05 for all), with the single exception that chromium (Cr) concentrations were significantly higher in toothpastes manufactured in Turkiye than in imported products (p = 0.028). Mercury and arsenic excluded from group comparisons because both were below detection limits in all samples; copper excluded because detected in only two samples.

Evidence Fitness

Strong occurrence evidence for the Turkish market. ICP-MS with a CRM-validated calibration and triplicate measurements provides reliable multi-element quantification. Sample size is small (15 products total; subgroup sizes of 3-8 limit statistical power for between-group comparisons). Single sampling point per product; no batch-to-batch variability data. The study is a valid primary occurrence survey for the Turkish toothpaste market segment, though it represents a snapshot rather than a distributional characterisation. Useful for adding a Turkish-market data point to the cross-jurisdictional evidence base for the Toothpaste (Cat 2) (Cat 2) page.

Methods (brief)

Sampling: 15 commercially available toothpaste products purchased from retail markets in Turkiye. Classified by target group (children’s, adult), formulation (conventional, herbal/natural), and country of origin (manufactured in Turkiye vs. imported) using product labelling.

Digestion: microwave-assisted nitric acid digestion. 1 g toothpaste + 5 mL concentrated HNO3 digested using a microwave digestion system. Exact microwave programme not specified in the methods section of the available text. Volume made up to 15 mL with ultrapure water (implied from instrument setup).

Quantification: ICP-MS (instrument model not stated). Calibration over 5.0 x 10^-4 to 1.0 ppm depending on element. Correlation coefficients (R2) for all elements >=0.9962 (Table 3). LOQ = 3.3 x LOD. Sampler probe rinsed with ultrapure water, 2% HNO3, and ultrapure water between measurements. All measurements in triplicate.

Speciation: Total metals only. arsenic (As) and mercury (Hg) recorded as total arsenic (tAs) and total mercury (tHg); no speciation for inorganic arsenic or methylmercury.

Limitations the authors state (pp. 9-10): small sample size within each subgroup; single sample per brand; batch-to-batch variability not evaluated; potential variations from different production lots not assessed; source of heavy-metal contamination (raw material or manufacturing) not determinable from a single-sample per brand design.

Implications

Certification (HMTc): Contributes Turkish-market occurrence data for the Toothpaste (Cat 2) (Cat 2 Row 11) evidence base. The dataset’s most notable finding is that total arsenic and total mercury were below detection limits in all 15 samples, and cadmium and lead were detected at low concentrations with all HQ values below 1.0 for both children and adults. The highest single-product lead concentration (0.12421 ppm in S6, a herbal children’s toothpaste) is below the EU 0.5 ppm limit and well below the FDA 20 ppm and Turkey 1 ppm limits, though the basis of the ICP-MS measurement needs verification against the EU limit’s reference basis before a formal exceedance ruling. No threshold values are proposed on this page.

Courses: Useful as a teaching case for the multi-jurisdictional regulatory spread on toothpaste metals (Turkey 1 ppm Pb, EU 0.5 ppm Pb, FDA 20 ppm Pb — a 40-fold range) and for illustrating how ICP-MS LODs enable detection of cadmium and lead at sub-ppm concentrations that flame AAS studies may miss. The absence of detectable arsenic and mercury across all 15 samples, contrasted with the Chengappa 2025 India AAS study where arsenic was detected in 19 of 20 samples, reflects either true market differences, formulation differences, or analytical sensitivity differences between ICP-MS (this study) and AAS (Chengappa).

App: Not directly applicable. Toothpaste is outside the consumer-app scope (food ingredients).

Measurement basis notes

Basis of Pb measurement relative to regulatory limits: The paper reports Pb concentrations in ppm (mg/kg or mg/L of digested solution — this is not explicitly stated in the methods section visible here). The EU limit of 0.5 ppm is a finished-product concentration on an as-sold basis. The comparison between the measured S6 Pb of 0.12421 ppm and the EU limit is basis-dependent; if the ICP-MS values are on a digested-solution basis, conversion to as-sold basis requires the dilution factor (1 g toothpaste in 15 mL total volume implies a 15-fold dilution factor, meaning the as-sold Pb would be approximately 1.86 ppm, which would exceed the EU 0.5 ppm limit). The paper’s own text states that the detected concentrations “remained within accepted safety limits” with “no exceedance” for lead, suggesting the authors are comparing their values to the Turkey 1 ppm limit rather than the EU limit at 0.5 ppm. This basis ambiguity is flagged for the synthesis pass and is not resolved on this page.

Related evidence

• Toothpaste (Cat 2)
• Lead
• Cadmium
• Arsenic, Total
• Mercury, Total
• Aluminum
• Chromium
• Nickel

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