Toxicological effects of leachate extracts from asphalt mixtures nanomodified under Daphnia magna and Landoltia punctata test organisms

• Published in: Chemosphere (Oxford) 2021-12, Vol.285, p.131463-131463, Article 131463
• Main Authors: Facin, Fernanda, de Melo, João Victor Staub, Lalau, Cristina Moreira, Nogueira, Diego José, Puerari, Rodrigo Costa, Matias, William Gerson
• Format: Article
• Language: English
• Subjects: Aquatic organisms; Asphalt binders; Carbon nanotube; Leaching; Organophilic nanoclay; Toxicity evaluation
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.131463

The incorporation of nanomaterials in binders in the paving area has been studied to improve the mechanical behavior of asphalt mixtures. However, asphalt mixture compounds are susceptible to leaching and deposition in the environment. In this context, this research aimed to investigate the toxic effect of two leachate extracts from asphalt mixtures nanomodified with 2% carbon nanotube and 3% organophilic nanoclay, compared to conventional mixture, using Daphnia magna and Landoltia punctata as test organisms. The nanomaterials were characterized to confirm morphology, stability and effective diameter. Extracts were chemically characterized using the Fourier-Transform Infrared Spectroscopy (FTIR) technique, which indicated presence of functional groups of the asphalt binder in greater intensity in the leachate from conventional mixture. Acute toxicity with D. magna indicated EC50,48h of 83.5 ± 6.2 mL/L for leachate extract from conventional mixture, 306.0 ± 87.6 mL/L for leachate extract from mixture with nanoclay and 464.8 ± 32.1 mL/L for leachate extract from mixture with carbon nanotube. No leachate caused significant chronic toxicity. As for L.punctata, concentrations that caused 50% growth inhibition were 127.5 mL/L for the leachate extract from mixture with carbon nanotube, 196.9 mL/L for the leachate extract from mixture with nanoclay and 205 mL/L for the leachate extract from conventional mixture. For these test organisms, there is no evidence of negative impacts directly associated with the use of the present nanomaterials in asphalt mixtures. The incorporation of these nanos may also reduce the acute toxicity of the mixtures. [Display omitted] •The extracts of the nanomodified mixtures have lower acute toxicity (Daphnia magna).•No leachate showed significant effects on chronic toxicity (Daphnia magna).•All leachate extracts have a low degree of toxicity to the macrophyte.•Carbon nanotube and nanoclay can reduce the toxicity of asphalt mixtures.