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?
This original study examines heavy metal accumulation in sweet potato irrigated with untreated, semi-treated, and treated textile effluents versus lake water controls in Hawassa, Ethiopia. Using pot trials over January–June 2016, the authors quantified Cu, Zn, Cr, and Cd in irrigation water, soils, and tubers; measured plant growth, gas exchange, and stomatal traits; and estimated dietary exposure and target hazard quotients. Copper, zinc, and chromium were consistently detected, while cadmium was below detection. The work links heavy metal accumulation in sweet potato to irrigation source, bioaccumulation and translocation behavior, and human health risk metrics relevant to certification schemes such as HTMC.
Who was studied?
The experimental crop was sweet potato (Ipomoea batatas) cultivar ‘Kulfo’ grown in pots with a sand–compost–topsoil mix under field conditions at Hawassa University. Irrigation waters were sampled once from three textile-lagoon stages—untreated (Site 1), semi-treated (Site 2), treated (Site 3)—and from Lake Hawassa as a control. Plant physiological measurements were taken during vegetative growth; biomass and tubers were analyzed at 150 days after planting. To support exposure estimates, a survey of 90 local adults characterized sweet-potato consumption patterns for Estimated Daily Intake and Target Hazard Quotient calculations.
Most important findings
| Critical point for HTMC | Details for certification relevance |
|---|---|
| Soil contamination profile | Geo-accumulation index categorized Zn as “moderately polluted” and Cu/Cr as “unpolluted to moderately polluted,” signaling persistent Zn loading risk in production soils. |
| Tuber metal concentrations | Treated effluent irrigation minimized Cu in tubers (2.80 µg g⁻¹ dw), whereas untreated effluent maximized Zn (30.94 µg g⁻¹) and treated effluent maximized Cr (0.57 µg g⁻¹); Cd was not detected. |
| Translocation behavior | Although EDIs for Zn (up to 0.53 µg/day), Cu (up to 0.101 µg/day), and Cr (up to 0.009 µg/day) were far below provisional tolerable daily intakes, relative differences trackthe irrigation source. |
| Plant performance indicators | Untreated effluent reduced vine length compared to control; semi-treated effluent increased photosynthesis and transpiration but decreased stomatal density, reflecting physiological stress trade-offs (Tables 2–4). 837-847 |
| Estimated Daily Intake (EDI) | Although EDIs for Zn (up to 0.53 µg/day), Cu (up to 0.101 µg/day), and Cr (up to 0.009 µg/day) were far below provisional tolerable daily intakes, relative differences track the irrigation source. |
| Target Hazard Quotient (THQ) | THQs for Cu and Zn exceeded 1 across scenarios; untreated effluent produced the highest overall risk profile (Zn THQ ≈1.75; Cu THQ ≈2.48), warranting precaution even when EDIs are low. |
| Certification trigger metals | Zn showed the strongest soil accumulation and frequent tuber elevation; Cu accumulated readily in edible tissues under untreated effluent; Cr was variable but peaked under treated effluent, indicating treatment-stage monitoring needs. |
Key implications
For HTMC, the heavy metal accumulation in sweet potato data implies that regulatory limits must prioritize Zn and Cu as primary compliance drivers, with Cr as a conditional trigger linked to treatment stage. Certification requirements should mandate source-water characterization, soil I_geo screening, and tuber metal testing at harvest. Industry applications include effluent-stage controls and crop-selection guidance. Research gaps include chronic, multi-crop exposure and speciation effects. Practical recommendations are to avoid untreated effluent, audit treatment performance, and verify tuber metals before market release.
Citation
Roro AG, Beshir HM, Terfa MT, Tesfaye B, Nadew F, Olango TM. Accumulation of heavy metals in soil and sweet potato (Ipomoea batatas) irrigated with treated and untreated textile effluents. Journal of Applied Sciences. 2019;19(9):837-847. doi:10.3923/jas.2019.837.847
Chromium (Cr) is a widely used metal with significant public health implications, especially in its toxic hexavalent form. The HMTC program’s stricter regulations ensure that chromium exposure is minimized, safeguarding consumer health, particularly for vulnerable populations.
Cadmium is a persistent heavy metal that accumulates in kidneys and bones. Dietary sources include cereals, cocoa, shellfish and vegetables, while smokers and industrial workers receive higher exposures. Studies link cadmium to kidney dysfunction, bone fractures and cancer.
