Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied?
Biochar and poultry manure reduce cassava heavy metals in a mining-degraded landscape in Ghana. The study evaluated whether circular economy amendments—biochar at 10 t/ha, poultry manure at 10 t/ha, and a 1:1 combination at 10 t/ha each—could improve cassava yield and nutritional quality while reducing bioaccumulation of arsenic, cadmium, mercury, and lead in tubers, compared with unamended “galamsey” soil and a nearby forest-topsoil control. The randomized complete block field trial ran over two cropping cycles (2019–2021) at Asikasu in the Forest–Savannah Transition Zone; site context is shown on the map on page 3. Outcomes included stover and tuber yields, proximate composition, and tuber metal concentrations analyzed by AAS.
Who was studied?
The crop species was cassava (Manihot esculenta) variety CRI-Abrabopa, selected for local adaptation and virus resistance. Plots were 12 m² with 16 plants per plot, planted on degraded mine soil versus forest soil 400 m away; treatments were applied four weeks pre-planting and management followed standard agronomic care. Samples for nutrient and heavy metal analyses were collected from mature plants at 12 months in each of two years, with laboratory methods for proximate composition and AAS metal quantification as described in the methods section
Most important findings
| Critical point | Details |
|---|---|
| Heavy metal mitigation | In Year 1, the combined biochar + poultry manure (1:1) reduced tuber As from 2.06 to 0.843 mg/kg and Pb from 4.87 to 1.64 mg/kg versus unamended galamsey plots; forest-topsoil control showed Pb ≈ 0.98 mg/kg. In Year 2, As remained significantly lower under amendments (≈ 0.386–0.545 mg/kg) than unamended (0.706 mg/kg). These magnitudes are directly relevant to certification thresholds. |
| Yield response | Stover biomass increased significantly in Year 1 under the combined treatment (22.85 t/ha), indicating improved nutrient capture; tuber yield differences were not statistically significant, highlighting that biomass gains did not automatically translate to economic yield. |
| Nutritional quality | Year 1 cassava tubers from combined treatment had elevated protein (3.32%) and higher total ash (~10.6%) compared with galamsey control (protein 2.34%, ash 7.95%). In Year 2, combined treatment maintained the highest protein (3.42%). Protein/ash changes indicate improved micronutrient delivery and matrix binding capacity. |
| Mechanistic plausibility | Authors attribute metal reductions to sorption/immobilization from biochar surface area and organic ligands in manure, limiting metal availability for root uptake; the discussion links to literature on biochar–organic matter binding and sorption site formation. |
| Regulatory salience | Reported first-year Pb and As decreases of roughly two-thirds relative to unamended plots demonstrate pathway control at field scale, aligning with HTMC goals to verify raw-material inputs, growing conditions, and product contaminant ceilings. |
| Site representativeness | Study location is an illegal-mining-degraded site within a sensitive agroecological zone; the map on page 3 and control placement support external validity for similarly impacted smallholder contexts. |
Key implications
For HTMC programs, the evidence supports specifying biochar and poultry-manure amendments as validated mitigation steps in cassava supply chains on degraded soils. Primary regulatory impacts include documenting amendment rates, application timing, and post-harvest testing of As and Pb. Certification requirements should include plot-level AAS verification across seasons. Industry applications span remediation-linked sourcing and agronomic SOPs. Research gaps include long-term metal dynamics and cyanogenic glycoside interactions. Practical recommendations emphasize combined amendments, batch characterization of biochar, and periodic soil-tuber monitoring.
Citation
Asante KOH, Abugre S, Akoto DS, Derkyi NSA. Cassava (Manihot esculenta) yield, nutrition, and heavy metal bioaccumulation responses to circular economy-based innovations in a mining-degraded landscape. International Journal of Plant & Soil Science. 2023;35(22):840-850. doi:10.9734/IJPSS/2023/v35i224195
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
