Soche Wastewater-Irrigated Vegetable Gardens (Blantyre, Malawi)

A cluster of vegetable gardens around the Soche Wastewater Treatment Plant in Blantyre, Malawi, irrigated with the plant's effluent. Growers cultivate three exotic Brassica varieties alongside three indigenous leafy crops — pumpkin, sweet potato and amaranth leaves.

Around the Soche Wastewater Treatment Plant in Blantyre, Malawi — built in the 1950s and extended in the 1970s — local farmers irrigate vegetable gardens with the plant's effluent. Whether the growers are organised, and on what terms, is not described in the 2025 study documenting the site.

Vegetable growing for consumption and sale that relies on treatment-plant effluent as the irrigation source. No organic or inorganic fertiliser was applied to the plots during the study period. Revenues and market channels are not reported in the source.

The plant gives growers an irrigation source through the dry season without buying fertiliser, but a 2025 assessment found soil zinc at 56.4 ± 0.5 mg/kg against a WHO limit of 36 mg/kg, vegetable stems at 4.65 mg/kg chromium (limit 2.3) and 4.09 mg/kg lead (limit 0.3), and leaves at 0.31 mg/kg cadmium (limit 0.2). Health risk indices reached 92.28, indicating chronic health risk. The assessment covered a single time point in November, so seasonal variation is unassessed.

This entry is compiled from the public sources, official sites and research below.

• PaperAssessment of Heavy Metal Accumulation in Wastewater-Receiving Soil-Exotic and Indigenous Vegetable Systems and Its Potential Health Risks: A Case Study from Blantyre, Malawi ↗pmc.ncbi.nlm.nih.gov