Dulshan and colleagues evaluated a clay-and-rice-husk point-of-use water filter for removal of nephrotoxic water constituents associated with CKDu-prevalent areas in Sri Lanka. This is a2 mitigation evidence: it uses synthesized feed waters and treatment performance metrics rather than a packaged-water occurrence survey.
Key numbers
The synthetic wet-season feed water contained hardness 350 mg/L, fluoride 3 mg/L, cadmium 1 mg/L, and aluminum 1 mg/L. The synthetic extreme-wet-season feed water contained hardness 150 mg/L, fluoride 1 mg/L, cadmium 1 mg/L, and aluminum 1 mg/L.
Average treated-water concentrations were, for the wet season, hardness 340 mg/L, fluoride 0.92 mg/L, cadmium 0.69 mg/L, and aluminum 0.74 mg/L; for the extreme-wet season, hardness 148 mg/L, fluoride 0.87 mg/L, cadmium 0.58 mg/L, and aluminum 0.67 mg/L.
The paper notes that hardness did not meet the Sri Lankan drinking-water guideline of 250 mg/L during the wet season and cadmium did not meet the WHO guideline of 0.003 mg/L in either season. Aluminum and fluoride remained within the cited WHO permissible values of 0.9 mg/L and 0.6-1.5 mg/L, respectively.
Methods (brief)
The filter media consisted of clay mixed with sifted rice husk. Feed waters were synthesized to simulate wet and extreme-wet conditions in the Sri Lankan dry zone. Samples were analyzed assuming a family consumption scenario of 8 L/day, and the filter media were characterized by XRD, FTIR, and ESEM-EDX.
Implications
Certification: Do not use this source in product-occurrence or packaged-water pools. It is mitigation evidence from synthetic feed-water treatment tests.
Courses: Useful as a cautionary mitigation example because the filter improved fluoride and aluminum but remained inadequate for cadmium and hardness under the tested conditions.
App: Context-only mitigation evidence for household water-treatment design.
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Verification notes
Recovered under the 2026-06-10 inclusion-by-default rule from a prior skip:not-food-occurrence lineage. The paper is direct point-of-use treatment evidence even though it uses synthesized water rather than a retail product matrix.
Products and ingredients are intentionally empty. This is filter-performance evidence in simulated source-water conditions, not occurrence surveillance in a market product.
Update history
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