eDNA enables proof-of-origin of samples from reservoirs with rich and abundant biodiversity

Environmental DNA (eDNA) is increasingly used for biodiversity monitoring, but its application in verifying the geographic origin of samples remains limited. Here, we evaluated whether eDNA profiles from water samples can indicate sample provenance across three large Brazilian reservoirs. Using multi-marker metabarcoding (COI, 12S, 16S), we showed that biodiversity signatures enable spatial attribution. To ensure traceability, each report was encoded in a machine-readable format, hashed, and registered on the blockchain. This framework demonstrates a novel approach to independently verifying sample origin through molecular and cryptographic evidence.