Estimation of Some Metals in Children's Colorful Modeling Clay Sold in the Markets of Erbil City, Kurdistan Region, Iraq

Overview

Jalal and colleagues measured cadmium (Cd), total chromium (Cr), Cu, and nickel (Ni) in colorful children’s modeling clay sold in Erbil city markets. The paper is routeable for art and craft materials because it reports finished-product clay concentrations in mg/kg after acid digestion and FAAS analysis. The source uses brand tables; this page keeps values at aggregate or de-identified sample/category level under the brand firewall.

Key numbers

• Sample frame: nine modeling-clay brands bought from Erbil city markets in January 2018, with 54 color samples analyzed. Seven main colors were collected for most brands; Italian- and German-origin brands had fewer available colors.
• Table 2 and the abstract report detection counts across 54 clay samples: total Cr detected in 0; Cd in 5; Cu in 36; Ni in 40.
• Table 3 aggregate concentration ranges, all copied as mg/kg: Cu ND - 819.20; Cd ND - 0.87; total Cr ND; Ni ND - 61.10.
• The paper states that Cr speciation as Cr(III) versus Cr(VI) was not performed or identified. The chromium result is therefore total Cr context only, not Cr(VI).
• Brand-level total detected-metal load ranged from 23.31 mg/kg to 221.41 mg/kg across the nine de-identified brand groups. The brand/order labels are suppressed here because the source’s table is brand-coded.
• Regulatory comparison quoted by the authors: for EN 71-3:2013 Category I pliable toy materials, the paper lists Cu 622.5 mg/kg, Ni 75 mg/kg, Cd 1.3 mg/kg, Cr(III) 37.5 mg/kg, and Cr(VI) 0.02 mg/kg.
• The authors state that all 54 samples were below those EU Category-I migration limits for the investigated metals except 1 colorful pliable clay sample.
• The single exceedance was a blue clay sample with Cu 819.2 mg/kg, above the source-listed Cu Category-I limit of 622.5 mg/kg. The consumer brand name is not repeated on this page.
• The highest Ni value reported was 61.10 mg/kg, below the source-listed Ni Category-I limit of 75 mg/kg.
• Cd was reported as 0.87 mg/kg in one mixed-color sample, 0.21 mg/kg in two red/mixed-color samples from another group, and 0.20 - 0.21 mg/kg in two red/mixed-color samples from a third group; all are below the source-listed Cd Category-I limit of 1.3 mg/kg.
• ANOVA across seven brand groups reported no statistically significant difference among mean concentrations at 95 % confidence: p-value > 0.05, with p-value 0.057, F 3.14, and F(critical) 3.287. Two groups were excluded because only a few colors were available.

Methods (brief)

The study wet-digested 1.0 g portions of modeling clay with 15 ml concentrated HNO3 65% followed by 5 ml concentrated HClO4 70%, then diluted digests to 50 ml. Cd, Ni, Cu, and Cr were measured by flame atomic absorption spectrometry using wavelengths Cd 228.8 nm, Ni 232.0 nm, Cu 324.8 nm, and Cr 357.9 nm. Blank solutions were prepared and repeated three times for samples and working solutions. Results are reported in mg/kg (ppm) as content in the clay material; no migration test or bioaccessibility experiment was performed.

Related evidence

• Art & craft materials (paints, markers, crayons, colored pencils, inks, adhesives/glues, modeling clay, putties/gels/slimes, glitter/pigments, jewelry/craft kits)
• Other toys/crafts (case-by-case)
• Cadmium
• Chromium
• Copper
• Nickel

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git.