Zerihun et al. 2015 - Ethiopian cannabis leaf metals

Zerihun et al. measured calcium, zinc, nickel, copper, cadmium, lead, and total chromium in Cannabis sativa L. leaves collected from four regions of Ethiopia. The samples were dried and reported on a dry-weight basis. Chromium was measured as total chromium; the paper explicitly says it was not possible to know the specific chromium form in the leaves, so no Cr(VI) value is inferred.

Key numbers

Table 7 reports mean concentrations as mean ± SD, n = 9, μg/g dry weight.

The abstract and conclusion summarize the same dry-weight ranges as Ca 657-1,511, Zn 321-380, Ni 124-172, Cu 122-176, Cd 3-10 in the abstract but 3.2-4.7 in the Table 7 and conclusion, Pb 8-10 in the abstract but 7.9-10.2 in Table 7 and the conclusion, and Cr 4-8 in the abstract but 3.6-7.6 in Table 7 and the conclusion. This page uses the Table 7 values for the occurrence table and records the abstract rounding as a source summary only.

Table 5 gives method detection limits in μg/g dry weight: Ca 25, Cr 1, Ni 8, Cu 19, Zn 31, Cd 0.4, and Pb 6.0.

Table 6 reports recovery-test percentages: Ca 92.9, Cr 100, Ni 97.3, Cu 102.5, Zn 91.7, Cd 87.5, and Pb 90.5.

Methods (brief)

Leaves were washed with tap water and deionized water, sun-dried until constant weight, ground, and sieved. For each bulk sample, 0.5 g of dried homogenized powder was digested with 10 mL of HNO3:HClO4 at 9:1 (v/v) at 300°C for 4:00 h, diluted to 25 mL, and analyzed by flame atomic absorption spectrometry. Calibration curves used external standards and three replicate determinations for each sample and standard; reagent blanks were digested in parallel.

Implications

The source provides small-n, dry-weight occurrence context for cannabis leaves used as botanical raw material in Ethiopia. It is not a finished-product market survey, and the regional means should not be pooled with finished cannabis-derived oils, edibles, or topical products without preserving the matrix and basis. The total chromium values should remain total chromium context only.

Wiki pages this source may touch

• supplements-botanicals-herbs
• herbal-botanicals
• cadmium
• lead
• chromium
• nickel
• copper
• zinc

Verification notes

• Identity checks before writing found no existing DOI, raw-handle, or cite-key page for 10.1186/s40064-015-1145-x, MFK_zerihun2015, or zerihun2015-ethiopian-cannabis-leaf-metals.
• All Key numbers were rechecked against /tmp/hmi-june9-zerihun2015.txt, extracted with pdftotext -layout, especially Tables 5, 6, and 7.
• Speciation check: chromium is reported as total Cr. The paper states that Cr(III) and Cr(VI) forms were not distinguished, so no Cr(VI) value is inferred.
• Units and basis are preserved as μg/g dry weight; no conversions were performed.
• Sample count note: sample_n: 4 reflects the four regional cannabis-leaf bulk samples. Table 7’s n = 9 is retained in the Key numbers as the source’s replicate analytical count for each regional mean.
• Brand firewall: no brands are reported; samples were confiscated or police-collected regional plant material.
• Missing slug note: the taxonomy snapshot has no cannabis-specific product or ingredient slug. Frontmatter uses broad [[ingredients/herbal-botanicals]] and [[products/supplements-botanicals-herbs]], with cannabis leaf terms retained only as matrix descriptors.

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.