Contamination by Hazardous Elements in Low-Priced Children's Plastic Toys Bought on the Local Markets of Karachi, Pakistan

Overview

Gul and colleagues measured total metal concentrations of Pb, Cd, Ni, Zn, total Cr, Cu, and Mn in 44 low-priced children’s plastic toys purchased from local markets in Karachi, Pakistan. The raw file is the Research Square version 1 preprint, which states that a version of record was published in Environmental Science and Pollution Research with DOI 10.1007/s11356-022-19362-0. The routeable evidence is finished-toy total metal concentration in mg/kg for plastic toy substrate materials and plastic toys with paint or coatings; the paper compares those total concentrations with EU, U.S. CPSC, Canadian, and BIS toy limits but does not report a migration or bioaccessibility assay.

Key numbers

• Sample frame: 44 low-priced toys purchased from Karachi local markets, stalls, mall stores, bargain stores, roadside vendors, and retail toy shops. The study targeted plastic toys designed for children around 3-5 years old and mostly demanded by low-income groups.
• Groups: children’s plastic toys (DCT, n = 23) and children’s plastic toys with paint or coating (DPCT, n = 21).
• Analytes: Pb, Cd, Ni, Zn, total Cr, Cu, and Mn as total metal concentrations (TMCs) in mg/kg.
• EU scraped-off toy material comparison limits copied from Table 1: Pb 23 mg/kg, Cd 17 mg/kg, Ni 930 mg/kg, Cr 460 mg/kg, Zn 46,000 mg/kg, Mn 15,000 mg/kg, and Cu 7700 mg/kg.
• Overall Table 4 summary for all 44 toys: average Pb 292.68 mg/kg, Cd 63.24 mg/kg, Cr 244 mg/kg, Zn 239.06 mg/kg, Cu 136.67 mg/kg, Ni 362 mg/kg, and Mn 779.25 mg/kg.
• Overall Table 4 ranges for all 44 toys: Pb 0.62-1190 mg/kg, Cd 0.34-459.01 mg/kg, Cr 90-560 mg/kg, Zn 20-1036.48 mg/kg, Cu 3.07-821.35 mg/kg, Ni 110-3000 mg/kg, and Mn 0.96-3240 mg/kg.
• Overall EU-limit exceedance counts from Table 4: Pb 64% (28), Cd 45% (20), Cr 5% (2), and Ni 2% (1). Zn, Cu, and Mn are shown as not exceeding the listed EU limits.
• Overall U.S. CPSC and BIS exceedance counts from Table 4: Pb 30% (13), Cd 16% (7), and Cr 45% (20).
• Overall Canadian exceedance count from Table 4: Pb 30% (13); the table shows no Cd exceedance under the Canadian comparison.
• DCT group averages from Table 5a: Pb 205.3391 mg/kg, Cd 85.64783 mg/kg, Ni 225.9217 mg/kg, Cr 153.1739 mg/kg, Zn 220.9304 mg/kg, Mn 894.7826 mg/kg, and Cu 135.6652 mg/kg.
• DCT EU-limit exceedance counts: Pb 83% (19), Cd 65% (15), Ni 4% (1), and Cr 9% (2).
• DPCT group averages from Table 5b: Pb 263.3952 mg/kg, Cd 17.86667 mg/kg, Ni 98.33333 mg/kg, Cr 65.61905 mg/kg, Zn 259.7524 mg/kg, Mn 541.9048 mg/kg, and Cu 118.5619 mg/kg.
• DPCT EU-limit exceedance counts: Pb 43% (9) and Cd 24% (5); Ni, Cr, Zn, Cu, and Mn are shown as not exceeding the EU limits in DPCT.
• Highest values named in the Results: Pb 1191 mg/kg in DPCT14 and 1111 mg/kg in DCT07; Cd 459 mg/kg in DCT11 and 426.1 mg/kg in DCT13; Cr 561 mg/kg in DCT03 and 479 mg/kg in DCT07; Ni 3000.1 mg/kg in DCT08.

Table 2 DCT sample values

Concentrations are copied as mg/kg; ND is the source table’s non-detect notation.

Table 3 DPCT sample values

Concentrations are copied as mg/kg; ND is the source table’s non-detect notation.

Methods (brief)

The authors purchased 44 low-priced toys from Karachi markets and grouped them into DCT and DPCT sets. Toy bodies were cut into small pieces; some samples were crushed or ground, and different parts and colors from the same toy were combined into one composite sample per toy. Two preparation approaches were used: dry ashing for some toys followed by digestion with high-purity HNO3 (65%) and H2O2 (30%), and direct acid treatment to remove paint/coating for coated samples. Standards, blanks, and digests were analyzed at Global Environmental Lab Karachi using an Atomic Absorption Spectrophotometer (AAS-Thermo Scientific Series Model iCE 3000).

Implications

Certification (HMTc): This source supports Pakistan-market occurrence context for low-priced plastic toys, with separate DCT substrate and DPCT paint/coating tables. It should not be pooled with migration-test datasets without preserving the total-content basis and Pakistan market frame.

Courses: The paper is a compact example of why total metal concentration, migration limits, and chromium speciation must be separated. The chromium measurements are total Cr by AAS, not Cr(VI).

App: If toy-material context is surfaced, this source can say that the Karachi low-priced-toy sample found Pb and Cd exceedances in both unpainted plastic toys and painted/coated plastic toys, with lower-frequency Cr and Ni exceedances in the total sample set.

Wiki pages this source may touch

• Toy substrate materials (accessible plastics/metals/woods/rubbers)
• General toys with paint/surface coatings
• Lead
• Cadmium
• Nickel
• Zinc
• Chromium
• Copper
• Manganese

Verification notes

• PDF text was extracted with pdftotext -layout to /tmp/ingest.txt; the title page, abstract, methods, Tables 1-5, Results/Discussion, and Conclusion were checked against this page.
• Identity checks before creation: Research Square DOI 10.21203/rs.3.rs-1001076/v1, version-of-record DOI 10.1007/s11356-022-19362-0, exact title, raw handle MFK_cat21-18-research-square-rs1001076, raw SHA-256 44d418f1cec4b56f81947b914acf3a844fbfa9eea435c8f870257f47dda73ae7, and candidate cite keys gul2022-karachi-plastic-toys-metals / gul2021-karachi-plastic-toys-metals were searched in wiki/sources/ and data/evidence/; no existing source page was found.
• Version note: the local raw PDF is the Research Square version 1 preprint and carries DOI 10.21203/rs.3.rs-1001076/v1; its first page states that a version of record was published in Environmental Science and Pollution Research on March 7, 2022 at DOI 10.1007/s11356-022-19362-0. Frontmatter uses the version-of-record DOI for deduplication but the numbers on this page are extracted from the local preprint PDF.
• Units: all toy sample concentrations are copied as mg/kg; no conversion was performed. Table 1 regulatory comparison limits are copied as mg/kg except the source’s U.S. CPSC Cd entry shown as 200ug.
• Speciation: Cr is total chromium measured by AAS. The page does not substitute Cr(VI) for total Cr. Pb, Cd, Ni, Zn, Cu, and Mn are reported as total elemental concentrations.
• Brand firewall: no consumer brand names are attached to contamination values. Sample descriptions such as Painted car 4, Lion, and Crocodile are de-identified product-form/sample descriptors from the source table and are preserved for provenance.
• Product slug note: DCT values route to toys-substrate-materials; DPCT values route to toys-painted. There is no separate matrix slug for non-food toy material, so matrices is intentionally empty.
• Source-internal anomalies preserved: Table 4 reports Pb maximum 1190 mg/kg, while Table 3 and the Results text list DPCT14 Pb as 1191 mg/kg; Table 4 reports Cd maximum 459.01 mg/kg, while Table 2 lists DCT11 Cd as 459; Table 3 lists DPCT14 Cd as 09. These are copied as the source renders them rather than normalized.
• Evidence tier: B because the version of record is peer-reviewed and the study reports sample-level values and methods, but the local extracted PDF is the preprint version and the sample frame is a small local market survey.

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. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.