Extraction of biodegradable microplastics from tissues of aquatic organisms

New insights into changes in phosphorus profile at sediment-water interface by microplastics: Role of benthic bioturbation

Microplastics (MPs) have attracted increasing attention due to their ubiquitous occurrence in freshwater sediments and the detrimental effects on benthic invertebrates. However, a clear understanding of their downstream impacts on ecosystem services is still lacking. This study examines the effects of bio-based polylactic acid (PLA), fuel-based polyethylene terephthalate (PET), and biofilm-covered PET (BPET) MPs on the bioturbator chironomid larvae (Tanypus chinensis), and the influence on phosphorus (P) profiles in microcosms. The changes in biochemical responses and metabolic pathways indicated that MPs disrupted energy synthesis by causing intestinal blockage and oxidative stress in T. chinensis, leading to energy depletion and impaired bioturbation activity. The impairment further resulted in enhanced sedimentary P immobilization. For larval treatments, the internal-P loadings were respectively 11.4%, 8.6%, and 9.0% higher in the PLA, PET, and BPET groups compared to the non-MP control. Furthermore, the influence of bioturbation on P profiles was MP-type dependent. Both BPET and PLA treatments displayed more obvious impacts on P profiles compared to PET due to the changes in MP bioavailability or sediment microenvironment. This study connects individual physiological responses to broader ecosystem services, showing that MPs alter P biogeochemical processes by disrupting the bioturbation activities of chironomid larvae.

Comparison of three digestion methods for microplastic extraction from aquaculture feeds

Microplastics (MPs) are ubiquitous pollutants found in aquaculture animals that may threaten human health through the food chain. However, there is a lack of effective methods for extracting MPs from aquaculture feeds containing complex components such as organic matter and fish bones. Therefore, in the present study, the extraction efficiency of three digestion methods using 30 % H2O2, Fenton reagent, and 30 % H2O2 + HNO3 for different particle sizes and types of MPs in aquaculture feeds was investigated and compared. The total digestion efficiency of the aquaculture feeds by 30 % H2O2 was 97.3 ± 0.1 %, while the recovery efficiency of MPs was 91.3 ± 1.1 % -103.1 ± 0.9 %. However, there was a large deviation in the extraction efficiency of MPs from aquaculture feeds by the Fenton reagent and 30 % H2O2 + HNO3. Notably, the surface morphology, particle size distribution, and oxidation degree of MPs hardly changed after 30 % H2O2 digestion. More importantly, the changes in the spectral features and carbonyl index of MPs after 30 % H2O2 digestion were smaller than those of the Fenton reagent and 30 % H2O2 + HNO3, which did not affect the identification of MPs. Overall, 30 % H2O2 was more efficient in extracting MPs from aquaculture feeds, and no significant effect on the characteristics of MPs was observed. This work provides novel insights into the effect of chemical pretreatment on the extraction of MPs in aquaculture feeds and provides an optimal protocol for the detection of MPs in aquaculture feeds.

Recent Study of Separation and Identification of Micro- and Nanoplastics for Aquatic Products

Micro- and nanoplastics (MNPs) are polymeric compounds widely used in industry and daily life. Although contamination of aquatic products with MNPs exists, most current research on MNPs focuses on environmental, ecological, and toxicological studies, with less on food safety. Currently, the extent to which aquatic products are affected depends primarily on the physical and chemical properties of the consumed MNPs and the content of MNPs. This review presents new findings on the occurrence of MNPs in aquatic products in light of their properties, carrier effects, chemical effects, seasonality, spatiality, and differences in their location within organisms. The latest studies have been summarized for separation and identification of MNPs for aquatic products as well as their physical and chemical properties in aquatic products using fish, bivalves, and crustaceans as models from a food safety perspective. Also, the shortcomings of safety studies are reviewed, and guidance is provided for future research directions. Finally, gaps in current knowledge on MNPs are also emphasized.

Understanding the Impact of Biodegradable Microplastics on Living Organisms Entering the Food Chain: A Review

Microplastics (MPs) pollution has emerged as one of the world's most serious environmental issues, with harmful consequences for ecosystems and human health. One proposed solution to their accumulation in the environment is the replacement of nondegradable plastics with biodegradable ones. However, due to the lack of true biodegradability in some ecosystems, they also give rise to biodegradable microplastics (BioMPs) that negatively impact different ecosystems and living organisms. This review summarizes the current literature on the impact of BioMPs on some organisms-higher plants and fish-relevant to the food chain. Concerning the higher plants, the adverse effects of BioMPs on seed germination, plant biomass growth, penetration of nutrients through roots, oxidative stress, and changes in soil properties, all leading to reduced agricultural yield, have been critically discussed. Concerning fish, it emerged that BioMPs are more likely to be ingested than nonbiodegradable ones and accumulate in the animal's body, leading to impaired skeletal development, oxidative stress, and behavioral changes. Therefore, based on the reviewed pioneering literature, biodegradable plastics seem to be a new threat to environmental health rather than an effective solution to counteract MP pollution, even if serious knowledge gaps in this field highlight the need for additional rigorous investigations to understand the potential risks associated to BioMPs.

Periodic and quasi-periodic one-dimensional phononic crystal biosensor: a comprehensive study for optimum sensor design

The resonant acoustic band gap materials have introduced an innovative generation of sensing technology. Based on the local resonant transmitted peaks, this study aims to comprehensively investigate the use of periodic and quasi-periodic one-dimension (1D) layered phononic crystals (PnCs) as a highly sensitive biosensor for the detection and monitoring of sodium iodide (NaI) solution. Meanwhile, a defect layer is introduced defect layer inside the phononic crystal designs to be filled with NaI solution. The proposed biosensor is developed based on the periodic PnCs structure and quasi-periodic PnCs structure. The numerical findings demonstrated that the quasi-periodic PnCs structure provided a wide phononic band gap and a large sensitivity compared to the periodic one. Moreover, many resonance peaks through the transmission spectra are introduced for the quasi-periodic design. The results also show that the resonant peak frequency changes effectively with varying NaI solution concentrations in the third sequence of the quasi-periodic PnCs structure. The sensor can differentiate between concentrations ranging from 0 to 35% with a 5% step, which is extremely satisfying for precise detection and can contribute to a variety of issues in medical applications. Additionally, the sensor provided excellent performance for all the concentrations of the NaI solution. For instance, the sensor has a sensitivity of 959 MHz, a quality factor of 6947, a very low damping factor of 7.19 × 10^-5, and a figure of merit of 323.529.

Mass Spectrometry-Based Techniques for the Detection of Non-Intentionally Added Substances in Bioplastics

The safety of food contact materials is a hot topic since chemicals can migrate from packaging into food, thus raising health concerns about and/or producing changes in the organoleptic properties of foodstuffs. Migration tests are required to demonstrate the compliance with current regulations and to investigate the transferred compounds. In this context, mass spectrometry is the analytical technique of choice for the detection and quantitation of both intentionally added substances, such as antioxidants, stabilizers, processing aids, and non-intentionally added substances (NIAS). Untargeted strategies represent a major analytical challenge, providing a comprehensive fingerprinting of the packaging material and migrating components, allowing for NIAS identification. Hyphenated mass spectrometry-based techniques have been devised for screening the presence of migrating contaminants and for quantitation purposes. Both low-resolution (LRMS) and high-resolution (HRMS) methods were screened, with a special emphasis on the latter because of its capability to directly characterize food contact materials with minimal/no sample preparation, avoiding chromatographic separation, and reducing sample handling, analysis costs, and time. Examples related to the migration of contaminants from existing or newly developed bioplastic materials will be discussed, providing an overview of the most used MS-based methods, covering the state-of-the-art approaches from 2012 up to 2022.

Identification and Quantification of Micro-Bioplastics in Environmental Samples by Pyrolysis-Gas Chromatography-Mass Spectrometry

Bioplastics are materials that are biobased and/or biodegradable, but not necessarily both. Concerns about environmental plastic pollution are constantly growing with increasing demand for substituting fossil-based plastics with those made using renewable resource feedstocks. For many conventional bioplastics to completely decompose/degrade, they require specific environmental conditions that are rarely met in natural ecosystems, leading to rapid formation of micro-bioplastics. As global bioplastic production and consumption/use continue to increase, there is growing concern regarding the potential for environmental pollution from micro-bioplastics. However, the actual extent of their environmental occurrence and potential impacts remains unclear, and there is insufficient mass concentration-based quantitative data due to the lack of quantitative analytical methods. This study developed and validated an analytical method coupling pressurized liquid extraction and pyrolysis-gas chromatography-mass spectrometry combined with thermochemolysis to simultaneously identify and quantify five targeted micro-bioplastics (i.e., polylactic acid (PLA), polyhydroxyalkanoate, polybutylene succinate, polycaprolactone, and polybutylene adipate terephthalate (PBAT)) in environmental samples on a polymer-specific mass-based concentration. The recovery of spiked micro-bioplastics in environmental samples (biosolids) ranged from 74 to 116%. The limits of quantification for the target micro-bioplastics were between 0.02 and 0.05 mg/g. PLA and PBAT were commonly detected in wastewater, biosolids, and sediment samples at concentrations between 0.07 and 0.18 mg/g. The presented analytical method enables the accurate identification, quantification, and monitoring of micro-bioplastics in environmental samples. This study quantified five micro-bioplastic types in complex environmental samples for the first time, filling in gaps in our knowledge about bioplastic pollution and providing a useful methodology and important reference data for future research.