Orisakwe et al. 2016 - toxic metals in toothpastes commonly used in Nigeria

Orisakwe and colleagues measured lead, cobalt, total chromium, nickel, and cadmium in 35 toothpaste products purchased in Port Harcourt, Nigeria. The paper reports finished-product mg/kg concentrations for 20 local/manufactured-in-Nigeria toothpastes and 15 imported toothpastes, then models daily metal intake and target hazard quotients from incidental toothpaste ingestion. The source names commercial products in its tables and abstract, so this page reports category-level ranges and strata only under the HMI brand firewall.

Key numbers

• Article identity: original article in Rocz Panstw Zakl Hig 2016;67(2):197-204; received 04.11.2015; accepted 21.03.2016; no DOI is printed in the extracted PDF.
• Sample frame: 35 toothpaste products purchased in March 2013 from supermarkets/shopping malls in Port Harcourt, Rivers State, Nigeria. The paper classifies 20 as local/manufactured in Nigeria and 15 as foreign/imported.
• Analytical basis: concentrations are finished toothpaste as purchased, reported in mg/kg. No wet/dry conversion or ppm conversion was performed for this page.
• Overall concentration ranges across all 35 toothpastes (mg/kg): Pb 4.514-23.575; Co 1.055-16.336; total Cr <0.001-10.854; Ni 5.472-18.631; Cd <0.001-2.490.
• Local/manufactured-in-Nigeria toothpastes (n=20, mg/kg): Pb 4.514-23.575; Co 1.989-12.712; total Cr <0.001-5.968; Ni 5.472-18.631; Cd <0.001-1.284.
• Imported toothpastes (n=15, mg/kg): Pb 6.329-18.092; Co 1.055-16.336; total Cr <0.001-10.854; Ni 8.975-18.535; Cd <0.001-2.490.
• Limits of detection: Cd, total Cr, Co, and Ni 0.001 mg/kg; Pb 0.01 mg/kg; blank values read as 0.00 mg/kg for all metals in deionized water with electrical conductivity below 5 uS/cm.
• Daily-intake model: the study adapted 0.264 g/person/day toothpaste ingestion, 60 kg body weight for adults, and THQ inputs including exposure frequency 365 days/year, exposure duration 35 years, adult body weight 60 kg, and child body weight 15 kg.
• Source-side oral reference doses and upper tolerable daily intakes in Table 3: Pb RfD 0.004 mg/kg/day, UL 0.240 mg/day; Cd RfD 0.001 mg/kg/day, UL 0.064 mg/day; total Cr RfD 1.5 mg/kg/day, no UL set; Ni RfD 0.020 mg/kg/day, UL 1 mg/day; Co RfD 0.043 mg/kg/day, no UL set.
• Risk-model outputs: the authors state that all target hazard quotients were below 1; DMI and THQ values for children were lower than adults in their model. They also state that all imported toothpaste daily-intake estimates were below the cited ULs.
• Source-side inconsistency: the text states that one local toothpaste’s cadmium daily-intake estimate exceeded the Garcia-Rico et al. UL, while the abstract/conclusion state the UL, THQ, and daily-intake rates were normal. This page preserves the inconsistency rather than resolving it.

Methods (brief)

The authors used a market-basket protocol and bought 35 toothpaste products from supermarkets/shopping malls in Port Harcourt, Rivers State, Nigeria, in March 2013. Samples were divided into local/manufactured-in-Nigeria and foreign/imported groups. The method text states that Teflon labware was cleaned in a trace-metal-clean sequence; samples were dry-ashed by heating at 200oC for 45mins, then in a furnace at 500oC, followed by digestion with 10 mL concentrated aqua regia (HCl:HNO3, 3:1). Digests were diluted with 20 mL deionized water, filtered, made up in volumetric flasks, and measured by flame atomic absorption spectrophotometry 205A.

Samples were analyzed in triplicate, and replicate analyses of several samples had an error range of +/- 2%. The paper reports LODs for Cd, total Cr, Co, Ni, and Pb, but does not report certified reference materials or recovery percentages.

Speciation: chromium is reported as total Cr. The paper does not report Cr(VI), inorganic arsenic, methylmercury, or total mercury.

Implications

Certification (HMTc): This is direct finished-product occurrence evidence for toothpastes sold in the Nigerian market, with usable category-level and local/imported ranges for Pb, Cd, Co, total Cr, and Ni. It should not be used for brand ranking, and it should not be treated as a US-market benchmark distribution.

Courses: The source is a useful example of the brand firewall: the underlying tables identify product names, but a source page can still preserve occurrence evidence by aggregating to product class and import/local strata. It also illustrates the need to keep total chromium distinct from Cr(VI).

App: If oral-care product profiles are surfaced, this source can support a Nigeria-market toothpaste context card with mg/kg category ranges and a note that the authors’ THQ model stayed below 1. It should not display brand-by-brand contamination values.

Wiki pages this source may touch

• toothpaste
• lead
• cadmium
• cobalt
• chromium
• nickel

Verification notes

• PDF text was extracted with pdftotext -layout to /tmp/mfk_june8_nigeria_toothpaste_toxic_metals.txt. The title/byline, abstract, Materials and Methods, Tables 1-3, Results/Discussion, conclusion, and received/accepted dates were checked against this page.
• No DOI is printed in the extracted PDF. Identity checks before creation found no existing source page for the exact title, no raw-handle hit for MFK_potential-hazards-of-toxic-metals-found-in-toothpastes, no raw-SHA hit for d8add8482deac85716a118765a6e9d7bb4638ddd25dee944e6bb9f187100d3fe, and no cite-key page at wiki/sources/orisakwe2016-nigeria-toothpastes-metals.md.
• Numbers and units were copied from the extracted text without conversion. The range summaries were computed directly from Tables 1 and 2 while preserving censored values as <0.001 where that is the lower bound.
• Speciation: chromium is recorded as total Cr only. The paper does not report Cr(VI), so no Cr(VI) route or claim is made.
• Brand firewall: the source names commercial toothpaste products in Tables 1 and 2 and in the abstract’s examples. This page suppresses brand-by-value rows and reports only local/imported and all-sample ranges.
• Evidence tier: B because this is a peer-reviewed finished-product occurrence study with 35 market samples, triplicate AAS measurements, and reported LODs, but no DOI, no CRM/recovery data, and no non-Nigerian market coverage.
• Routing audit: npm run evidence:source-routes exited 0; this source generated 1 toothpaste product routing row, was absent from data/evidence/routing_unresolved.csv, and had only the expected nonblocking ingredients advisory in data/evidence/routing_malformed.csv.

Page history

The five most recent substantive edits to this page. 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.