Developmental toxicity of curcumin-mediated silver nanoparticles in the freshwater snails Biomphalaria glabrata

Curcumin-mediated silver nanoparticles (Curc-AgNPs) are promising biogenic nanomaterials in medical and environmental applications. However, their ecotoxicological impact to non-target aquatic species remains understood. This study assessed the toxicity of Curc-AgNPs in the neotropical freshwater snails Biomphalaria glabrata, considering multiple developmental and post-hatching endpoints, including embryonic mortality, hatching success, developmental progression, heart rate, embryonic cell viability, and mortality of newly hatched snails. Curc-AgNPs (14 ± 4 nm) were synthesized by reducing AgNO₃ with curcumin and characterized by multiples techniques. Curc-AgNPs induced mortality, hatching inhibition, developmental delay, decreased heart rate and cell viability in a time- and concentration-dependent pattern. The cumulative developmental toxicity was confirmed by declining 50% effective concentration (LC50) to embryos (20.96 mg L^-1 at 24 h to 1.47 mg L^-1 at 168 h) and newly hatched snails (53.7 mg L^-1 at 24 h to 37.5 mg L^-1 at 120 h). Curc-AgNPs almost completely inhibited snail hatching at concentrations ≥ 1.88 mg L^-1 and delayed embryonic development, mainly at gastrula and trochophore stages. Sub-lethal effects were observed in terms of cardiac activity (heart rate reduced by ∼41% at 1.88 mg L^-1) and reduced cell viability in embryos exposed to Curc-AgNPs at concentration ranging 0.18 to 0.75 mg L^-1. Also, Curc-AgNPs induced higher toxicity in embryos than in newly hatched B. glabrata, indicating that the early developmental stages of gastropod are more susceptible to the toxicity of Curc-AgNPs. Overall, Curc-AgNPs exhibited pronounced embryotoxicity and stage-dependent molluscicidal effects. Although toxic, these concentrations exceed predicted environmental levels, representing hazard, not environmental risk.