Raman Tweezers for Small Microplastics and Nanoplastics Identification in Seawater

Author: Raymond Gillibert, Gireeshkumar Balakrishnan, Quentin Deshoules, Morgan Tardivel, Alessandro Magazzù, Maria Grazia Donato, Onofrio M. Maragò, Marc Lamy de La Chapelle, Florent Colas, Fabienne Lagarde and Pietro G. Gucciardi
Year of Publication: 2019
Published: Environmental Science & Technology 53, 9003-9013

Abstract:
Our understanding of the fate and distribution of micro- and nano- plastics in the marine environment is limited by the intrinsic difficulties of the techniques currently used for the detection, quantification, and chemical identification of small particles in liquid (light scattering, vibrational spectroscopies, and optical and electron microscopies). Here we introduce Raman Tweezers (RTs), namely optical tweezers combined with Raman spectroscopy, as an analytical tool for the study of micro- and nanoplastics in seawater. We show optical trapping and chemical identification of sub-20 μm plastics, down to the 50 nm range. Analysis at the single particle level allows us to unambiguously discriminate plastics from organic matter and mineral sediments, overcoming the capacities of standard Raman spectroscopy in liquid, intrinsically limited to ensemble measurements. Being a microscopy technique, RTs also permits one to assess the size and shapes of particles (beads, fragments, and fibers), with spatial resolution only limited by diffraction. Applications are shown on both model particles and naturally aged environmental samples, made of common plastic pollutants, including polyethylene, polypropylene, nylon, and polystyrene, also in the presence of a thin eco-corona. Coupled to suitable extraction and concentration protocols, RTs have the potential to strongly impact future research on micro and nanoplastics environmental pollution, and enable the understanding of the fragmentation processes on a multiscale level of aged polymers.

Keywords:
Raman, Microplastic, Nanoplastic, Seawater

Citation:
Gillibert, R., Balakrishnan, G., Deshoules, Q., Tardivel, M., Magazzù, A., Donato, M. G., Maragò, O. M., Lamy de La Chapelle, M., Colas, F., Lagarde, F., Gucciardi, P. G., 2019. Raman Tweezers for Small Microplastics and Nanoplastics Identification in Seawater. Environmental Science & Technology 53, 9003-9013.

Link:
https://doi.org/10.1021/acs.est.9b03105

Secondary nanoplastics released from a biodegradable microplastic severely impact freshwater environments

Author: Miguel González-Pleiter, Miguel Tamayo-Belda, Gerardo Pulido-Reyes, Georgiana Amariei, Francisco Leganés, Roberto Rosal and Francisca Fernández-Piñas
Year of Publication: 2019
Published: Environmental Science: Nano

Abstract:
Over the last five decades, plastics production has increased as a consequence of their use in strategic sectors causing damage on aquatic ecosystems. In this context, biodegradable plastics have emerged as an ecological alternative because they are easily degradable in the environment. Despite the recent advances in the field of plastic ecotoxicology, the ecological impact of secondary nanoplastics (nanoplastics resulting from natural degradation of micro and macro plastics) in the environment remains poorly understood. Here, we have investigated the effects of secondary nanoplastics of polyhydroxybutyrate (PHB), a biodegradable plastic, on three representative organisms of aquatic ecosystems. Secondary PHB-nanoplastics were produced from PHB-microplastics by abiotic degradation under environmentally representative conditions. Secondary PHB-nanoplastics induced a significant decrease in cellular growth and altered relevant physiological parameters in all organisms. We investigated whether the observed toxicity was exerted by PHB-nanoplastics themselves or by other abiotic degradation products released from PHB-microplastics. An experiment was run in which PHB-nanoplastics were removed by ultrafiltration; the resulting supernatant was not toxic to the organisms, ruling out the presence of toxic chemicals in the PHB-microplastics. In addition, we have performed a complete physicochemical characterization confirming the presence of secondary PHB-nanoplastics in the 75–200 nm range. All results put together indicated that secondary PHB-nanoplastics released as a consequence of abiotic degradation of PHB-microplastics were harmful for the tested organisms, suggesting that biodegradable plastic does not mean safe for the environment in the case of PHB.

Keywords:
Nanoplastic, biodegradable microplastic, freshwater environments

Citation:
González-Pleiter, M., Tamayo-Belda, M., Pulido-Reyes, G., Amariei, G., Leganés, F., Rosal, R., Fernández-Piñas, F. (2020): Secondary nanoplastics released from a biodegradable microplastic severely impact freshwater environments. Environmental Science: Nano 2019 (6): 1382 – 1392

Link:
https://doi.org/10.1039/c8en01427b