Hossain et al. 2024 - cadmium uptake in salt-tolerant rice genotypes
Hossain and coauthors tested how soil pH and organic matter affected cadmium accumulation in rice grains grown in Cd-contaminated soil. This is controlled pot-experiment evidence for rice Cd drivers, not edible-salt occurrence evidence. The source is most useful for mitigation and source-apportionment logic because it links grain Cd to soil pH, organic matter, genotype, and soil-bioavailable Cd.
Key numbers
The Cd-stressed soil was spiked to 5 mg/kg (CdCl₂·2H₂O added to topsoil with baseline total Cd 2.60 mg/kg, pH 7.86, EC 1.90 dS/m, silty clay loam). Soil pH treatments were 4, 7, and 9; organic matter (cow dung) was applied at 1%, 2%, and 3%. Each treatment was replicated in triplicate under complete randomized design.
Grain Cd under the soil pH series (Table 2; reported in mg/kg dry-weight grain alongside soil bioavailable Cd):
| Variety | Soil pH | Grain Cd | Soil bioavailable Cd | Pearson r (grain × bioavailable) |
|---|---|---|---|---|
| BRRI 28 | 4 | 1.73 mg/kg | 0.56 mg/kg | 0.93** |
| BRRI 28 | 7 | 0.88 mg/kg | 0.37 mg/kg | |
| BRRI 28 | 9 | 0.74 mg/kg | 0.19 mg/kg | |
| Heera | 4 | 1.91 mg/kg | 0.68 mg/kg | 0.87** |
| Heera | 7 | 0.82 mg/kg | 0.48 mg/kg | |
| Heera | 9 | 0.75 mg/kg | 0.25 mg/kg | |
| BRRI 67 | 4 | 1.59 mg/kg | 0.60 mg/kg | 0.96** |
| BRRI 67 | 7 | 1.30 mg/kg | 0.40 mg/kg | |
| BRRI 67 | 9 | 0.78 mg/kg | 0.24 mg/kg | |
| BRRI 47 | 4 | 1.15 mg/kg | 0.53 mg/kg | 0.92** |
| BRRI 47 | 7 | 1.18 mg/kg | 0.43 mg/kg | |
| BRRI 47 | 9 | 0.72 mg/kg | 0.23 mg/kg |
Grain Cd under the organic matter series (Table 3, reported in mg/kg dry-weight grain alongside soil bioavailable Cd):
| Variety | Organic matter | Grain Cd | Soil bioavailable Cd | Pearson r |
|---|---|---|---|---|
| BRRI 28 | 1% | 1.00 mg/kg | 0.44 mg/kg | 0.99** |
| BRRI 28 | 2% | 0.61 mg/kg | 0.32 mg/kg | |
| BRRI 28 | 3% | 0.10 mg/kg | 0.18 mg/kg | |
| Heera | 1% | 1.15 mg/kg | 0.59 mg/kg | 0.95** |
| Heera | 2% | 0.32 mg/kg | 0.26 mg/kg | |
| Heera | 3% | 0.84 mg/kg | 0.38 mg/kg | |
| BRRI 67 | 1% | 1.17 mg/kg | 0.29 mg/kg | 0.99** |
| BRRI 67 | 2% | 0.53 mg/kg | 0.15 mg/kg | |
| BRRI 67 | 3% | 0.49 mg/kg | 0.13 mg/kg | |
| BRRI 47 | 1% | 0.41 mg/kg | 0.55 mg/kg | 0.92** |
| BRRI 47 | 2% | 0.19 mg/kg | 0.26 mg/kg | |
| BRRI 47 | 3% | 0.33 mg/kg | 0.35 mg/kg |
Transfer factor (TF = grain Cd / soil Cd) ranged 0.06–0.13 at low pH, 0.04–0.08 at neutral pH, and 0.04–0.09 at high pH; TF<1 for every variety × pH × OM cell. At pH 4 the highest TF was Heera (0.13) and the lowest was BRRI 47 (0.06).
Hazard quotient was calculated as HQ = grain Cd (mg/kg) × 9.47 (adult) or × 9.38 (child). HQ exceeded 1 for both adults and children in nearly every scenario; the only safe-zone result was BRRI 28 with 3% OM amendment, where HQ was 0.92 (adult) and 0.91 (child).
The authors report that low-pH soil increases Cd bioavailability and grain Cd, that raising pH or adding organic matter (up to 2%) reduces grain Cd, and that beyond 2% OM the effect partially reverses for some varieties (Heera at 3% OM accumulated more grain Cd than at 2%).
Methods (brief)
Topsoil (0–15 cm) from the Khulna University campus was air-dried, sieved to 2 mm, and spiked with CdCl₂·2H₂O at 5 mg Cd kg⁻¹. Soil pH was adjusted with NaOH or HCl to three levels (4, 7, 9) in one factorial; cow-dung organic matter was applied at three rates (1%, 2%, 3%) in a second factorial. Each treatment was replicated in triplicate in earthen pots under complete randomized design. Four rice cultivars were grown for the January–April 2021 season under continuous flooding: non-salt-tolerant BRRI 28 and Heera, and salt-tolerant BRRI 47 and BRRI 67.
Grain and soil samples were digested in HNO₃:HClO₄ (2:1 v/v) at 180 °C following Hseu (2004). Cd was quantified by atomic absorption spectrophotometry on a Shimadzu AAS System AA-7000 (Japan). Soil pH was read per Li et al. (2005); EC was measured on a Hanna HI2315 conductivity meter (Hardie and Doyle 2012). Triplicate samples, reagent blanks, and continuing check verifications were used for QA/QC. ANOVA with Tukey HSD at α = 0.05 was performed in STATISTIX v10.0. Transfer factor was reported as grain Cd / soil Cd. Hazard quotient followed Kibria et al. (2022): HQ = grain Cd (mg kg⁻¹) × 9.47 for adults and × 9.38 for children.
Implications
Certification: Not a market benchmark, because it is a pot experiment in spiked Cd-stressed soil. It is useful evidence for mitigation and source apportionment in rice.
Courses: Useful for explaining why soil pH and organic matter are practical levers for Cd uptake.
App: Should not directly set consumer rice occurrence values, but can inform source-risk flags.
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Verification notes
The fetched filename placed the paper in a salt Cd queue because “salt tolerant rice” appeared in the title. The actual matrix is rice grain from a controlled pot experiment, not edible salt; routing should ignore the salt cue from the filename. The sample_n: 36 frontmatter value represents the 4 varieties × 3 pH × 3 OM = 36 unique treatment cells; the paper ran two separate factorial experiments (pH series and OM series), each replicated in triplicate, so total pot count is higher. BRRI 28, BRRI 47, BRRI 67, and Heera are rice cultivar/genotype identifiers (Bangladesh Rice Research Institute lines and a private hybrid), not consumer brands, and are retained per the scientific-method exception to Part 12.
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.
| Commit | Date | Description |
|---|---|---|
| ae6c129 | 2026-07-01 | feat(auth): large login + role-based signup screens (design, burgundy) |