Plastics in the Aquatic Environment - Part I

The first volume of the book “Plastics in the Aquatic Environment” – “Part I: Current Status and Challenges” – gives insights into the role of environmental science and a global perspective. The volume includes 15 chapters dealing with different methods for sampling, sample preparation and analyses of these methods as well as monitoring studies and risks for organisms. Moreover, case studies about the plastic pollution problem from Asia, Latin America, and Europe are presented which gives the reader an integrated overview of the global scope of this issue.

The rising plastic production in the last 70 years led to an increase in plastic waste in the environment. Intensive research activities about macroplastics and microplastics (MPs) started some years ago. Different sampling strategies, sample preparations and analysis methods have been described in the literature for different environmental compartments and biota. Until the present, many papers have been published about the quality and quantity of MPs in different matrices. Pitfalls and limitations in MP analyses are often missing or not discussed. Therefore, this chapter summarizes the present methods for sampling, sample preparation and analysis, discusses the related limitations and outlines the complexity regarding MP loss or contamination during sampling and laboratory work.

Beside several studies about the occurrence of microplastic (MP) there is still a huge gap of knowledge regarding the dynamic processes of MP distribution and fate. Consequently, there is a need for reliable, fast, and robust analytical methods for MP monitoring. However, due to the physicochemical attributes of plastic, new analytical approaches fundamentally different from those for most other environmental contaminants are required. Promising strategies include spectroscopic and thermo-analytical methods. The two vibrational spectroscopic methods, Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy, have been implemented for MP detection. Especially in combination with particle finding software or a focal plane array (FPA) detector, they enable reliable determination of MP particle numbers in environmental samples. In recent years, different thermo-analytical techniques, such as pyrolysis (Py), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have been adapted for MP detection. All thermo-analytical methods are based upon measurement of physical or chemical changes of the polymer under thermal treatment. While DSC measures differences in heat flux caused by phase transitions of the polymer, TGA-MS is based upon detection of specific thermal degradation products. By means of a gas chromatographic separation step, an enhanced detection of the marker compounds is possible, enabling a more sensitive MP detection even in complex matrices. The extent of analytical information obtained as well as the complexity and effort of the methods increase by TGA-DSC < TGA-MS < Py-GC-MS/TED-GC-MS. The results are comparable to those of spectroscopic methods (FT-IR, Raman), but both techniques have different benefits and limitations. While thermo-analytical methods require minor sample pretreatment and reveal mass concentrations, spectroscopic methods are non-destructive and yield particle numbers and size distribution by imaging techniques. Whichever is the most suitable method depends on the scientific question and what kind of information is required.

When it comes to bioplastics, it is important to differentiate between the biopolymer in its form as a macromolecule and the resulting bioplastic material as a ready-to-use material. Furthermore, a distinction must be made between bio-based and biodegradable plastics. Bio-based refers to the raw material origin of the polymer feedstock, while biodegradability describes an end of life option. However, both features are independent of each other. Although biodegradability describes a material property that depends on the microstructure and the chemical structure of the material, in practice biodegradability is a system feature, since there are a variety of environmental conditions, from industrial composting facilities to sewage treatment plants, soils in a variety of climatic regions, the beach and the seabed, or even the human body. It is, therefore, necessary to provide clear information about the environmental conditions and the point in time at which a material or product is biodegradable. In the area of compostability, some test standards for bioplastics and other organic substances cover various environmental conditions well, while test standards and also the understanding of degradation mechanisms in other areas, such as degradability in soil or in marine systems, are only available in small numbers and do not reflect the complex environmental conditions well.

Plastic debris is now ubiquitous in aquatic ecosystems worldwide and may impact different biological levels of organisation, with effects ranging from individual organisms to ecosystem functioning. Demonstrating these effects is not always straightforward, and there is uncertainty at every level. In particular, understanding of the wider impacts on biodiversity and ecosystem functioning is challenging, and little research has been done in this area. This chapter gives a broad overview of hierarchical impacts of macro- and microplastic pollution on aquatic ecosystems. Topics include the potential for microplastics to spread antimicrobial resistance and a summary of current knowledge concerning wider ecological impacts of macro- and microplastic debris such as changes to assemblage composition and structure and effects on nutrient cycling and primary productivity. The potential impacts of biodegradable plastics are also discussed and, in most cases, have similar effects to plastics made from conventional polymers emphasising that the same precautions need to be taken to ensure that these items do not become the litter of the future.

Plastic debris is gradually filling the seas, oceans, and freshwater bodies of the planet. Since the 1950s, a huge amount of plastic has entered into various bodies of water. All these objects decompose at different rates, and aquatic organisms take part in these processes. This book chapter provides an overview of studies carried out in recent decades on the interaction between microorganisms and plastic debris in the aquatic environment. Both prokaryotic communities and algo-bacterial cenoses are considered. A separate section is devoted to the research results of the authors of this book chapter, obtained in the natural environment, contaminated with plastic, and in field experiments in the sea.

The presence of plastics and microplastics in freshwater ecosystems and biota has been reported in different parts of the world – even in most remote areas. Yet, scientific information on the extent of freshwater microplastic pollution is limited. Comprehensive assessments on plastics and microplastics in freshwater environments at global, regional, and basin scales are lacking. Human health and ecological effects of freshwater microplastic pollution remain unknown. Freshwater microplastic pollution is a new research area recently attracting attention from the academic community. Further research is needed to improve scientific knowledge on microplastic pollution in the world’s freshwater resources and to develop evidence-based appropriate policies and solutions to reduce microplastics in freshwater environments. The role of international scientific programmes such as the International Initiative on Water Quality of UNESCO’s Intergovernmental Hydrological Programme (IHP) will be crucial for research promotion and knowledge generation to fill the knowledge gaps on freshwater microplastic pollution and its human health and ecological impacts.

The chapter focuses on the presence on microplastics in freshwater systems, their sources and pathways and associated potential human health and environmental risks. It presents a summary of the available scientific knowledge and information related to microplastics in freshwater environments, which were reviewed for a preliminary assessment of microplastics in freshwater environments conducted by UNESCO-IHP’s International Initiative on Water Quality between 2015 and 2017. Some studies published more recently have been included. It highlights knowledge gaps and research needs on freshwater microplastic pollution and recommends appropriate policies and solutions to prevent and reduce the discharge of microplastics to freshwater environments.

The model “From Land to Sea – Model for the documentation of land-sourced plastic litter” was developed on behalf of BKV GmbH, Frankfurt, Germany. This model systematically records for the first time discharges of improperly disposed-of plastic litter from Germany that gets into the North Sea, the Baltic Sea, and the Black Sea. All discharge pathways and sources are taken into account. A distinction is made between discharges of microplastic and macroplastic.

The weaknesses of existing plastic waste management strategies lead to the pollution of the natural environment. Although around 75% of plastic litter come from developing countries, an important 25% is originated in western countries mainly due to the limited efficiency of the collection systems and low recycling rates. Global plastic production has almost doubled over the last decade, and it is predicted that it will continue to grow. This chapter provides an extensive review of current waste management routes and existing recycling and recovery options. Two types of plastic products have been considered: rigid and flexible materials. These materials show different behaviour and usually are treated separately. Plastic waste sources can also be diverse, but they are commonly grouped into post-industrial and post-consumer. In this chapter, the focus has been placed on post-consumer plastics since a higher amount of this type of waste is being generated and its treatment is more challenging.

Despite the increasing environmental awareness, there is still an enormous amount of plastic waste generated which often ends up in the environment. Slovenia is not an exception, and in the past years, there was a lot of effort to minimize plastic pollution in terrestrial and aquatic environments. Since waste management is closely connected to plastic pollution, the first part of the chapter summarizes waste management practice and plastic waste handling in Slovenia. According to European statistical data, Slovenia belongs among countries, where a good waste management practice is well established; waste collection, recycling rate, and waste management are comparable to other developed countries. The book chapter also focuses on the plastic waste in Slovenia and how plastic pollution is treated from a governmental perspective as well as from the perspective of nonprofit organizations. The last part of the chapter is aimed to present research on plastic pollution and microplastics in Slovenia; to introduce current research efforts and trends in Slovenia; to discuss monitoring results and the impact of microplastics on the local environment; and to link these results to the global microplastic research.

Marine litter is a truly global challenge, changing all oceans and seas of the world. Every year, millions of tons of litter end up in the coastal and marine environment worldwide, resulting in environmental, economic, health, and safety impacts. This study investigated the abundance, composition, and sources of marine litter stranded on four beaches located at Durrës Bay and in the Gulf of Drin, which also includes Rodoni Bay and Shëngjini Bay along the Albanian southern-eastern Adriatic coastline. During the winter 2015, 12 beach transects were surveyed, covering 12,000 m² and extending over 1,000 m of the coastline. The mean litter density of the total four beaches studied was 219 items/100 m and 0.219 items/m². The majority of litter items (58%) were plastic or artificial polymer materials. Other bottles and containers (drums) were the most frequently found items with a percentage of 6%, followed by cartons/tetra pack (others) with 5.7% and by cigarette butts and filters with 3.7%. The sites investigated differed in terms of human-induced pressures with two sites classified as semi-urban: one site as urban and one as rural. Litter from shoreline sources such as tourism and recreational activities, including poor waste management practices, accounted for 37.5% of litter collected, accounting for the vast majority of litter items. Sea-based sources of litter (fisheries and aquaculture, shipping) amounted to 8% of total litter items on all beach locations.

Plastic pollution has become an increasingly worrying threat to the aquatic environment. The oceans and seas in East Asia are among the world’s most polluted. Therefore, East Asian societies should make concerted efforts to tackle the problem. In this review, we summarize the current state of scientific research about macro- and microplastic contamination of the aquatic environment, including biota, consecutively for four East Asian countries (China, Japan, South Korea, and Taiwan). For the same four countries, we also summarize mitigation efforts to decrease the plastic pollution in these four countries, which includes government policies and waste management; education, media, monitoring, and outreach campaigns by NGOs; and inventors and businesses developing alternative products and methods of production and recycling. This review aims to give an overview which will hopefully inspire a more concerted effort by East Asian governments to support the relevant science but also to tackle the plastic pollution problem with much needed policies and management solutions.

Microplastics, which are considered as emerging contaminants, have been reported to be leaked to the open environment on a global scale. Few studies have been conducted on the occurrence of microplastics on several water bodies in the country given the fact that the Philippines is considered to be the third largest contributor of plastics in oceans. This chapter described the composition and distribution of plastic wastes and quantified and characterized microplastics in terms of shape and polymer type in several rivers especially within Metro Manila draining to two of the most economically important water bodies, the Manila Bay and the Laguna de Bay. Extracted microplastics in sampling sites are mostly fragments derived from larger plastics (secondary microplastics) which signified the importance of an efficient solid waste management to reduce the leakage of the plastic waste and microplastics to the open environment.

The book volume “Plastics in the Aquatic Environment – Part I: Current Status and Challenges” gives an overview about the role of environmental science and provides a sense of the global perspective in dealing with plastic pollution. The volume contains 15 chapters, with two additional chapters written by the editors containing introductory remarks and concluding notes on the role of environmental science in tackling the plastic pollution problem. These 15 chapters present and discuss challenges in research, related, for example, to microplastics analysis, impacts of plastic litter on aquatic environments, plastic waste management, bioplastics; they also review case studies of plastic pollution and contamination in the Philippines, Brazil, Albania, Slovenia, Russia and East Asia, as well as the Mediterranean Sea at large. This chapter provides an overview of the conclusions drawn by the authors of the chapters of this book volume and gives an overall final discussion of the challenges discussed herein.