Contamination of the aquatic environment by nanoparticles is a threat to marine biota but remains poorly understood. Engineered nanoparticles tend to rapidly sediment in the aquatic environment. Once deposited on the bottom, they become less available to filter organisms, but become available to the bottom feeders and grazers, benthic organisms. In this context, the present study investigated the effects on the gastropod of a food substrate containing copper oxide and titanium dioxide nanoparticles (NPs) by evaluating metal accumulation in their tissues, cytotoxicity, lipid peroxidation products and genotoxicity. The results showed an increase in copper and titanium content in the soft tissues of after 14 days of exposure. Significant cytotoxicity and an increase in malondialdehyde concentration, an indicator of peroxidation of membrane lipid peroxidation, were observed. The results of the comet assay showed pronounced genotoxicity of both NPs, as reflected by an increase in the mean percentage of DNA in the comet tail, as well as an increase in the number of highly damaged comets. The results provided clear evidence that even though the nanoparticles penetrated the digestive system of the mollusk as part of the food substrate, they retained toxic properties. In addition, the food model used in the experiments may be a useful tool in ecotoxicological studies using gastropods and other organisms with similar feeding behavior.