The study addressed a persistent gap. Although Sub-Saharan Africa receives abundant solar radiation, solar cooking has seen limited adoption across the region, in part because imported devices are costly and locally adapted designs remain scarce. Standardised experimental comparisons between locally manufactured and commercial cookers are particularly rare in Central Africa. To fill that gap, the researchers built two box-type cookers, one parabolic cooker and one hybrid configuration using materials available in Lubumbashi, including recycled reflective components such as aluminium. They then benchmarked these prototypes against four commercial products: the SK14 and Yamo Dudo parabolic cookers, the Fornelia and the Brother.

Performance was assessed according to the Solar Cookers International Performance Evaluation Process, known as SCI-PEP, with standardised cooking power serving as the primary indicator. The measurements revealed substantial differences between technologies. Commercial parabolic cookers achieved the highest standardised performance of anything tested. The SK14 reached 185.06 watts, followed by the Yamo Dudo at 124.31 watts. The best locally manufactured device, the parabolic prototype, delivered 113.22 watts, placing it within reach of the commercial parabolics but still behind them.

The box-type cookers fared considerably worse in raw power terms. Their standardised performance ranged from 25.57 to 31.77 watts, while the hybrid configuration reached 26.95 watts. Those figures are roughly a fifth of what the SK14 achieved. Yet the authors argue that raw cooking power is not the only criterion that matters in resource-constrained settings. Box-type and hybrid designs, they note, balance safety, efficiency and fabrication simplicity, and their construction requires neither specialised components nor advanced manufacturing capacity.

One of the study’s most consequential findings concerns materials. Reflectance measurements showed that recycled aluminium-based materials can provide optical properties suitable for solar concentration, the mechanism by which reflective surfaces focus sunlight onto a cooking vessel. That result supports the use of salvaged reflective components in low-cost solar cooker manufacture, and it underpins the feasibility argument at the heart of the research: functional concentrating cookers can be assembled from what is locally available, rather than relying on imported hardware.

The authors are careful about what their results do and do not show. The locally manufactured cookers did not match the thermal performance of the commercial parabolic systems, and the study was a technical performance assessment under outdoor conditions in a single city, not a trial of household adoption, fuel savings or health outcomes. What the results do demonstrate is that locally built devices can achieve measurable, quantified cooking power using recycled and locally sourced materials, establishing a baseline for designs adapted to resource-constrained environments.

The broader context gives the work its urgency. In many Sub-Saharan African cities, household cooking remains heavily dependent on charcoal, a dependence that contributes to deforestation, greenhouse gas emissions and adverse health impacts. Lubumbashi reflects that pattern. The researchers suggest that locally manufactured solar cookers could serve as complementary clean cooking technologies in rapidly growing urban areas of the region, sitting alongside rather than entirely replacing existing cooking fuels.

For the field, the study offers something comparatively rare: head-to-head standardised numbers for locally manufactured and commercial solar cookers tested side by side under the same outdoor conditions. The SCI-PEP framework allowed the prototypes to be compared directly with established commercial products such as the SK14. The gap between the local parabolic prototype at 113.22 watts and the SK14 at 185.06 watts quantifies how far low-cost local fabrication currently trails commercial engineering, while the box-type results define the lower performance tier that simpler designs occupy.

The findings also carry practical implications for where different designs might fit. The commercial parabolics clearly lead on cooking power, but the locally built box-type and hybrid cookers offer fabrication simplicity and safety advantages that may matter for community-scale production. Meanwhile, the demonstration that recycled aluminium reflective surfaces perform adequately for solar concentration opens a low-cost pathway for workshops and local manufacturers to enter the field without importing specialised optics.

As urban populations across Sub-Saharan Africa continue to grow and charcoal demand with them, the Lubumbashi experiments provide a measured, protocol-based starting point. They show that the performance ceiling for locally built solar cookers is real but not prohibitive, that recycled materials can do the optical work of solar concentration, and that the study’s scope leaves questions of sustained household use, adoption and real-world fuel savings for future work to address.

Subject of Research: Comparative experimental performance testing of locally manufactured and commercial solar cookers under outdoor conditions in Lubumbashi, Democratic Republic of the Congo

Article Title: Comparative experimental assessment of locally manufactured and commercial solar cookers under outdoor conditions in Lubumbashi, Democratic Republic of the Congo

Article References: Balume Baderha, S., Bijnens, L., Abrams, S., Banza Wa Banza, B., & Deferme, W. (2026). Comparative experimental assessment of locally manufactured and commercial solar cookers under outdoor conditions in Lubumbashi, Democratic Republic of the Congo. Discover Sustainability. https://doi.org/10.1007/s43621-026-05004-9

Image Credits: AI Generated

DOI: 10.1007/s43621-026-05004-9

Keywords: solar cookers, Lubumbashi, Democratic Republic of the Congo, clean cooking, recycled materials, parabolic cooker, box-type cooker, SCI-PEP protocol, charcoal dependence, Sub-Saharan Africa, renewable energy, appropriate technology

The analytical backbone of the study is inductively coupled plasma optical emission spectrometry, or ICP-OES, a technique that excites atoms in a sample with a plasma torch and reads the characteristic wavelengths of light they emit to determine elemental concentrations with high precision. Using this method, the researchers measured heavy metal levels in spinach (Spinacia oleracea), Chinese cabbage (Brassica chinensis), amaranth (Amaranthus vulgaris), cassava (Manihot esculenta), onion (Allium cepa) and tomato (Solanum lycopersicum). Leafy vegetables emerged as the most contaminated group, a pattern consistent with the way leafy crops accumulate metals from both soil and airborne deposition. Spinach recorded a mean cadmium concentration of 4.02 milligrams per kilogram, lead at 1.44, copper at 25.27 and zinc at 136.21, all above the FAO and WHO thresholds that define safe levels for human consumption.

Cadmium deserves particular attention because of its toxicological profile. The metal has no known biological function in humans, accumulates primarily in the kidneys, and has a biological half-life measured in decades. Chronic exposure damages renal tubular function, weakens bones, and is classified as a human carcinogen. In Lubumbashi, decades of intensive mining and smelting of copper and cobalt ores have loaded surrounding soils and dust with cadmium and other metals, which then enter the food chain through crops grown in contaminated ground or irrigated with tainted water. The study’s findings confirm that this pathway is not hypothetical but measurable in the everyday food supply of an urban population that depends heavily on locally grown and locally sold produce.

To translate chemical concentrations into health outcomes, the team applied standard risk assessment metrics. The hazard quotient, or HQ, compares an estimated daily intake of a metal with its reference dose, the level below which adverse effects are not expected over a lifetime. When hazard quotients for multiple metals are summed, the result is the hazard index, or HI. Values above 1 signal a potential non-carcinogenic health risk. In this study, both HQ and HI values exceeded 1 for consumers of the contaminated vegetables, indicating that routine dietary exposure could plausibly produce harmful effects over time. The authors also calculated cancer risk, expressed as the incremental probability of developing cancer over a lifetime of exposure, and compared it against the regulatory acceptable range of 10 to the power of minus 6 to 10 to the power of minus 4.

The cancer risk results were stark. For cadmium, the computed cancer risk exceeded the acceptable range in three of the six vegetables studied: spinach at 6.22 times 10 to the power of minus 4, cassava at 5.05 times 10 to the power of minus 4, and amaranth at 3.49 times 10 to the power of minus 4. In practical terms, these figures represent probabilities of additional cancer cases on the order of several per ten thousand exposed individuals, well above the upper bound of what regulators typically tolerate. Because cassava is a dietary staple across the region and leafy greens are eaten daily in large quantities, the population-level implications are considerable. The metals are not distributed evenly across crops, however; onions and tomatoes generally accumulated less, suggesting that crop choice could become part of a practical risk reduction strategy.

What makes the study unusual is its second half, which turns from spectrometers to human minds. The researchers surveyed consumers in Lubumbashi about their awareness of food-chain contamination, their perception of the risks, and their purchasing behavior. The results revealed a striking paradox: even among respondents who knew that vegetables could be contaminated, preference for the highest-risk foods remained strong, with cassava in particular continuing to command loyalty. This disconnect between knowledge and behavior is a well-recognized challenge in environmental health, where awareness alone rarely changes practices when cultural attachment, taste, affordability and habit all pull in the opposite direction.

To probe the relationships statistically, the team used logistic regression, a modeling technique that estimates how predictor variables influence the odds of a binary outcome. The analysis showed that awareness significantly predicted knowledge, risk perception, and the adoption of safer practices. In other words, people who were better informed were more likely to understand the danger, to perceive themselves as exposed, and to take protective measures. That finding carries a hopeful message: information campaigns could shift behavior, provided they are designed with local realities in mind rather than simply broadcasting warnings that compete against economic necessity and culinary tradition.

The survey also uncovered a market signal with real policy potential. More than half of the respondents said they would be willing to pay a premium for safer food options, including vegetables produced hydroponically, a soil-free growing method that sidesteps contaminated ground entirely. In a city where mining has degraded urban and peri-urban soils so thoroughly that remediation may be impractical on the required scale, hydroponics offers a technologically credible alternative: crops grown in controlled nutrient solutions cannot inherit the metal burden of the soil beneath them. A consumer base willing to pay extra for such produce could give entrepreneurs and policymakers the economic justification to invest in clean production systems, turning public concern into a self-sustaining market for food safety.

The authors frame their findings as a call for integrated food safety policy interventions in mining-impacted urban settings, and the study’s structure shows why integration matters. Chemistry without behavioral science would have documented a hazard but missed the reasons consumers keep buying contaminated food; surveys without laboratory data would have captured perceptions without revealing how far reality departs from them. By combining ICP-OES measurements, quantitative risk assessment and regression-based analysis of consumer attitudes, the research delivers a complete picture of a food system under stress. The work was supported by the COCREATE-Africa project funded by the European Union under the Africa Academic Mobility Scheme, and was approved by the Research Ethics Committee of the Faculty of Agricultural Sciences at the University of Lubumbashi.

For Lubumbashi’s residents, the study confirms that the risk is real, measurable and concentrated in the foods they love most. For cities across the mining belts of Central Africa and beyond, it offers a template: measure the contamination, quantify the exposure, understand the behavior, and then design interventions that meet people where they are. The willingness of more than half of surveyed consumers to pay more for safer vegetables suggests the demand for clean food already exists. What remains is the supply, and the political will to build it.

Subject of Research: Heavy metal contamination of vegetables and associated health risks and consumer perceptions in the mining city of Lubumbashi

Article Title: Heavy metal human health risk assessment and consumer perception of vegetables in Lubumbashi, Democratic Republic of the Congo

Article References: Adam, S., Lwalaba, J. L. W., & Balasha, A. M. (2026). Heavy metal human health risk assessment and consumer perception of vegetables in Lubumbashi, Democratic Republic of the Congo. Discover Sustainability. https://doi.org/10.1007/s43621-026-04887-y

Image Credits: AI Generated

DOI: 10.1007/s43621-026-04887-y

Keywords: heavy metals, cadmium, food safety, mining contamination, vegetables, health risk assessment, consumer perception, Lubumbashi, Democratic Republic of the Congo, hydroponics, cancer risk, public health