Adebayo 2020 - Heavy metals in wastewater-irrigated spinach from Bauchi

Adebayo and coauthors measured cadmium, chromium, copper, manganese, nickel, and lead in irrigation wastewater and wastewater-grown African spinach from Railway Quarters in Bauchi, Nigeria. The paper is routeable for spinach occurrence evidence because it reports mean concentrations in the edible vegetable sample and a health-risk calculation based on local spinach consumption.

Key numbers

Table 1 reports heavy metals in Railway Quarters irrigation wastewater as mean +/- standard error, with units of ug/cm3:

Table 2 reports heavy metals in the spinach sample as mean +/- standard error, with units of mg/kg:

Table 3 reports daily intake of metals (DIM), reference oral dose (RfD), health risk index (HRI), and transfer factor. The abstract reports HRI values of 0.3000 for Cd, 0.0003 for Cr, 0.2150 for Cu, 0.1240 for Mn, 0.1250 for Ni, and 0.5000 for Pb, all below the authors’ HRI cutoff of 1.0.

The authors compare the measured spinach lead value of 6.60 mg/kg with an Indian Standard safe limit of 2.50 mg/kg and state that the lead level is above that comparison value. The concentration values should be treated as Nigerian wastewater-irrigated spinach context, not as a U.S.-market benchmark distribution.

Methods (brief)

The study collected wastewater and African spinach from the Railway Quarters irrigation farm in Bauchi, Nigeria. Edible vegetable parts were washed, air-dried, ground, sieved, and digested from a 1.00 g ground sample using a 5:1:1 mixture of nitric acid, sulfuric acid, and perchloric acid. Wastewater was digested from a 50.00 cm3 sample using concentrated nitric acid. The digests were analyzed by Bulk Scientific Atomic Absorption Spectrophotometer Model 210 VGP.

The paper reports total metals only. It does not provide arsenic speciation, mercury speciation, LOD/LOQ, sample-level replicates, or moisture-basis conversion. The spinach values are therefore routeable as source-reported mg/kg on the study’s dried/processed analytical basis, with basis caveats preserved.

Implications

Certification: The source supports spinach contamination context for Cd, Cr, Cu, Mn, Ni, and Pb under wastewater-irrigated conditions in Nigeria. It should not be pooled silently with U.S. market spinach because geography, irrigation source, and basis differ.

Courses: The source is a compact example of why wastewater irrigation can produce routeable produce measurements while still requiring jurisdiction and basis flags before benchmark pooling.

App: The study can inform a spinach risk explainer that distinguishes field contamination pathways from retail-market representativeness.

Wiki pages this source may touch

• spinach
• spinach
• cadmium
• chromium
• copper
• manganese
• nickel
• lead

Verification notes

The DOI, title, authors, journal, year, and sample location were read from the PDF first page. The key numeric concentrations were read from Tables 1 and 2, with HRI values cross-checked against the abstract and Table 3 heading. The paper identifies the vegetable as African spinach and gives the botanical name as Amarantus caudatus; this page routes it to the existing spinach row because the product queue targeted spinach and the paper repeatedly uses spinach as the consumed vegetable label.

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.