The marine environment is facing the threat of increasing plastic pollution, especially from disposable plastics. Presently, governments worldwide are promoting policies to restrict or prohibit conventional plastics. As one hopeful alternative to conventional disposable/non-durable plastics, biodegradable plastics have attracted much attention and controversy in terms of their definition, environmental impact, and environmental significance, as they may be widely used. Therefore, it is necessary to clarify the facts about biodegradable plastics, understand the current knowledge gaps, and identify promising fields of relevant research. This review briefly introduces some common biodegradable plastics, their mechanisms of biodegradation, indicators for the biodegradation process, and factors concerning biodegradability and summarizes studies on the biodegradation of biodegradable plastics in the marine environment. The lifespan of biodegradable plastics varies greatly due to their compositions/properties as well as significant differences in the marine environment. Then, the potential risks of biodegradable plastics, including the release of pollutants (micro/nanoplastics, degradation products, and additives), adsorption-desorption of pollutants (pesticide, etc.), and their impact on biomes and biogeochemical cycles are discussed, fully revealing their possible impacts on the marine environment. It is believed that, in addition to the waste of resources, a high abundance of microplastics, toxic leachates, and complex effects on habitats and the environment may also cause problems for the marine environment as a result of the widespread and inappropriate use of biodegradable plastics. Based on the discussion, some constructive suggestions on how to use biodegradable plastics reasonably and prudently in the future are put forward.

Plastic pollution in aquatic ecosystems has been identified as a growing global water pollution threat that is negatively impacting water quality and, as a result, affecting the health of humans, aquatic animals, and wildlife. Therefore, it presents a global environmental catastrophe that requires immediate attention. Plastics in water (in their different forms, macro-, meso-, micro-, and nanoplastics) are contaminants of emerging concerns that have since evolved to be a global environmental threat. Despite increasing levels of pollution in aquatic ecosystems, there are insufficient monitoring data to evaluate the extent of the catastrophe. Traditional methods of monitoring plastics in water are constrained by high sampling costs, intensive labor, and limited temporal and spatial coverage, which results in limited monitoring data. Thus, insufficient monitoring data limit our understanding of the true quantities and persistence of plastic particles in aquatic ecosystems, as well as the extent to which they impact the aquatic environment. There is increasing availability of free big geospatial data (amounting to petabytes/day) from satellite sensors for potentially monitoring plastics. This provides a possible solution to these challenges by minimizing the fieldwork required and therefore reducing the costs and sampling time. The study purpose of this review is to analyze advances in emerging technology such as the use of satellite sensors to monitor the occurrence of macro- and microplastics in freshwater, ultimately aimed at creating new operational monitoring solutions. This review: (1) examines the literature to identify trends, accomplishments, and limitations of using satellite data to monitor plastics in water; (2) identifies and compares traditional, and machine and deep learning satellite image classification methods for monitoring plastics in water; and (3) identifies research gaps and summarizes future perspectives and recommendations to improve monitoring methods.

Per- and polyfluoroalkyl substances (PFAS) encompass a large, heterogeneous group of chemicals of potential concern to human and environmental health. Based on information for some legacy PFAS, such as perfluorooctane sulfonate and perfluorooctanoate, there is an increasing awareness that they can represent a serious environmental risk. Although the environmental occurrence and fate of some legacy PFAS and their toxicity under controlled laboratory conditions have been investigated, to date, there is a dearth of information on the exposure and potential adverse effects of these compounds towards free-living organisms. The present review summarizes the findings of field studies investigating the accumulation and adverse effects induced by the exposure to environmental mixtures of both legacy and emerging PFAS in the wildlife living nearby fluorochemical production plants (FCP). Biomonitoring campaigns performed close to FCP, which can be considered as hotspots of PFAS contamination, can be very useful in exploring the fate and toxicity of these compounds towards free-living organisms. All studies showed that the bioaccumulation of both legacy and emerging PFAS in wildlife living near the FCP is higher compared to control sites and other areas worldwide. However, the investigation on adverse effects returned contrasting results, suggesting the need for further studies to shed light on the toxicity and mechanism(s) of action of PFAS in free-living organisms.

The fragmentation of plastic litter into smaller fragments, known as microplastics and nanoplastics, as well as their toxicity and environmental distribution have become issues of high concern. Furthermore, the popularization of bioplastics as a greener substitute of conventional plastics represents a challenge for the scientific community in view of the limited information concerning their potential environmental impact. Here, we systematically review the recent knowledge on the environmental fate and toxicity of nanoplastics in freshwater environments, discuss the results obtained thus far, and identify several knowledge gaps. The sources and environmental behaviors of nanoplastics are presented considering in vitro, in vivo, and in silico studies with a focus on real exposure scenarios. Their effects on organisms are classified based on their impact on primary producers, primary consumers, and secondary consumers. This review covers the main results published in the last four years, including all relevant experimental details and highlighting the most sensitive toxicity endpoints assessed in every study. We also include more recent results on the potential environmental impact of biodegradable plastics, a type of material belonging to the category of bioplastics for which there are still scarce data. This review identifies a need to perform studies using secondary nanoplastics rather than synthetic commercial materials as well as to include other polymers apart from polystyrene. There is also an urgent need to assess the possible risk of nanoplastics at environmentally realistic concentrations using sublethal endpoints and long-term assays.