Bioaccumulation and nutritional impact of fluoride in Pleurotus ostreatus and Pleurotus djamor with human health risk assessment.

Abstract

Pleurotus species are nutritionally rich fungi, yet their potential to bioaccumulate environmental fluoride (F⁻) necessitates careful scientific evaluation further. In this study, Pleurotus mushrooms cultivated on F⁻ enriched substrates exhibited significant bioaccumulation of F⁻, indicating their sensitivity to substrate quality and environmental contamination. Supplementation with calcium (Ca) played a crucial physiological role by reducing F⁻ toxicity within the fruiting bodies of mushroom, although its effects were species dependent. Notably, Ca addition mitigated F⁻ stress at the biochemical and cellular level in Pleurotus ostreatus, whereas P. djamor experienced a reduction in growth performance, demonstrating differential tolerance mechanisms. Molecular-level assessment through FTIR-spectroscopy highlighted marked alterations in functional groups associated with proteins, lipids, and carbohydrates under combined F⁻ and Ca exposure, emphasizing stress-induced metabolic shifts. Field-based evaluations further validated laboratory observations, revealing substantial F⁻ accumulation in mushrooms grown using fluoridated-straw and F⁻ rich groundwater, particularly in Set 1N (96.6 mg/kg-dw) and Set 4N (46 mg/kg-dw). Subcellular fractionation studies confirmed that accumulated fluoride predominantly localized within the cell wall fraction, suggesting a sequestration strategy for detoxification. Bioconcentration factor (BCF) analysis indicated higher accumulation in P. ostreatus relative to P. djamor. However, despite partial mitigation by Ca supplementation and health risk assessments demonstrated that both mushroom species exceeded the non-carcinogenic risk threshold for children when cultivated in traditional way under contaminated conditions. These findings underscore the importance of using controlled, F⁻ free substrates and clean irrigation sources to ensure food safety and promote sustainable mushroom cultivation practices, particularly in fluoride-affected regions such as West Bengal, India.