Hussain et al. 2016 - Spinach cadmium under soil Cd:Zn ratios

Hussain and colleagues tested whether changing the Cd:Zn ratio in contaminated soil changed cadmium uptake into edible spinach leaves. This is in-scope mitigation and soil-to-plant pathway evidence: the spinach was grown in deliberately Cd-spiked glasshouse soil, so these values should not be treated as ordinary market spinach occurrence.

Key numbers

The control soil was a sandy clay loam with pH 7.16, ECe 3.25 dS m-1, SAR 1.69 (mmol L-1)1/2, TSS 32.5 mmolc L-1, CaCO3 1.78%, and organic matter 0.72%. Table 1 reports AB-DTPA extractable Cd 0.08 mg kg-1, Pb 1.25 mg kg-1, and Zn 2.45 mg kg-1; total Cd 1.82 mg kg-1, Pb 13.55 mg kg-1, and Zn 27.5 mg kg-1.

The experiment used four soil treatments: control, Cd-contaminated soil at 3 mg kg-1, Cd-contaminated soil plus 30 mg Zn kg-1 (Cd:Zn 1:10), and Cd-contaminated soil plus 300 mg Zn kg-1 (Cd:Zn 1:100).

Table 2 reports dry matter yield as g pot-1:

Table 3 reports Cd and Zn concentrations in spinach leaves as mg kg-1:

Table 4 reports Cd and Zn concentrations in spinach roots as mg kg-1:

Table 5 reports cadmium transfer coefficients:

Table 6 reports AB-DTPA extractable Cd and Zn in post-harvest soil as mg kg-1:

The conclusion states that 300 mg Zn kg-1, corresponding to Cd:Zn 1:100, decreased spinach leaf Cd by 46.2% relative to the Cd:Zn 1:10 treatment, while 30 mg Zn kg-1 did not decrease spinach leaf Cd concentrations.

Methods (brief)

The study used uncontaminated soil collected at the Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad. Soil was artificially contaminated with CdCl2.2H2O at 3 mg Cd kg-1 and amended with Zn to produce Cd:Zn ratios of 1:10 and 1:100. Spinach was grown in 10 kg lined pots with three replicates per treatment. Leaves were harvested after eight weeks, washed, air-dried, ground, digested with HNO3 + HClO4 (3:1), and analyzed by atomic absorption spectrophotometry. Soil AB-DTPA extractable metals were also measured by atomic absorption spectrophotometry.

Implications

Certification: Do not pool these leaf Cd values as ordinary consumer spinach occurrence. They come from Cd-spiked glasshouse soil and are useful as controlled pathway and mitigation evidence.

Courses: Useful example of a mitigation intervention that is not monotonic. Moderate Zn did not lower leaf Cd, while high Zn lowered leaf Cd but also reduced spinach biomass.

App: Context only. This source can inform spinach Cd pathway notes and supplier questions about soil Cd and Zn management, not finished-product scoring.

Wiki pages this source may touch

• soil-to-plant-transfer
• remediation-evidence
• spinach
• spinach
• cadmium
• zinc
• lead

Verification notes

Recovered from skip:not-food-occurrence under the 2026-06-10 inclusion-by-default rule. On reading, the paper is in scope as lane a2 mitigation/remediation and lane a3 soil-to-plant transfer evidence because it measures Cd in spinach leaves, roots, and post-harvest soil under controlled Cd/Zn soil treatments.

Numbers were checked against the extracted PDF text, especially Tables 1-6 and the conclusion. Units are preserved as printed (mg kg-1, g pot-1, and coefficient values). Pb appears only in the baseline soil-characterization table and is not treated as spinach occurrence. Products and ingredients are intentionally empty because the experiment used spiked glasshouse soil rather than market spinach.

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.