Can photocatalytic and magnetic nanoparticles be a threat to aquatic detrital food webs?

Freshwaters are likely to serve as reservoirs for engineered nanomaterials (ENMs) due their accelerated unintentional release, increasing the relevance of assessing impacts on aquatic biota and ecosystem processes they drive. Stream-dwelling microbes, particularly fungi, invertebrate shredders play an essential role in decomposition organic matter transfer energy higher trophic levels. We assessed two photocatalytic (nano-TiO 2 erbium doped nano-TiO ) one magnetic (nano-CoFe O 4 ENMs detrital-based food webs freshwaters by exposing chestnut leaves, colonized stream-dwelling a series concentrations (0.25–150 mg L −1 these ENMs. Microbial biomass fungal communities, associated with were not affected However, activities antioxidant enzymes microbial decomposers significantly ( P < 0.05) stimulated concentration-dependent way, suggesting oxidative stress stream communities. The stronger responses biomarkers against (increase upto 837.5% catalase, 1546.8% glutathione peroxidase 1154.6% S-transferase) suggest toxicity this ENM comparing others. To determine whether effects could be transferred across levels, shredder Sericostoma sp. was exposed (1 50 5 days either via contaminated water or (leaf litter). Leaf consumption rate decreased water; more pronounced when exposure occurred (up 99.3%, 90.7% 90.3% inhibition nano-Er:TiO , nano-CoFe respectively). Overall, tested can harmful further compromising streams. • Impacts TiO Er:TiO CoFe detrital foodwebs. All induced microbes indicated enzymatic biomarkers. Sublethal varied type concentration. reduced plan-litter shredders. food.