Nanomaterials of various shapes and dimensions are widely used in the medical, chemical, and electronic industries. Multiple studies have reported the ecotoxicological effects of nanaoparticles when released in aquatic and terrestrial ecosystems; however, information on the toxicity of silver nanowires (AgNWs) to freshwater organisms and their transfer through the food webs is limited. In the present study, we aimed to evaluate the toxicity of 10- and 20-μm-long AgNWs to the alga Chlamydomonas reinhardtii, the water flea Daphnia magna, and the zebrafish and study their movement through this three-species food chain using a variety of qualitative and quantitative methods as well as optical techniques. We found that AgNWs directly inhibited the growth of algae and destroyed the digestive organs of water fleas. The results showed that longer AgNWs (20μm) were more toxic than shorter ones (10μm) to both algae and water fleas, but shorter AgNWs were accumulated more than longer ones in the body of the fish. Overall, this study suggests that AgNWs are transferred through food chains, and that they affect organisms at higher trophic levels, potentially including humans. Therefore, further studies that take into account environmental factors, food web complexity, and differences between nanomaterials are required to gain better understanding of the impact of nanomaterials on natural communities and human health.

In the present work, titanium dioxide nanowires (TNWs) were synthesised via hydrothermal method. Insertion of ZnFe ₂O ₄ nanoparticles to the surface of TNWs was done by sol gel combustion synthesis of the nanoparticles in the presence of the nanowires. The surface of prepared magnetic TNWs was modified by p -phenylendiamine and then it was used in preconcentration of Cu ²⁺ ion prior to their determination by flame atomic absorption spectroscopy. The sorbent was characterised by Fourier transform infrared spectra, EDX, FE-SEM and VSM techniques. We investigated and optimised various parameters influencing the preconcentration efficiency, such as the media pH, adsorbent quantity, contact time, sample volume and elution conditions. Under optimum conditions, the analytical performance of the method was evaluated. The calibration curve was found to be linear from 10.0 to 150 μg L ⁻¹ (R ² = 0.996). Calculated limit of detection was 0.43 μg L ⁻¹ (n = 5). The estimated relative standard deviation was 2.50% (n = 5). Moreover, the maximum adsorption capacity of the sorbent was 51.5 mg g ⁻¹ and preconcentration factor was 125. Capability of developed method was proved by applying it for preconcentration of Cu ²⁺ ion from food and water samples.