Climate change 2014 - Synthesis Report

https://scholarlypublications.universiteitleiden.nl/access/item%3A2978611/view

Microplastics in freshwater and terrestrial environments: Evaluating the current understanding to identify the knowledge gaps and future research priorities.

Plastic litter is widely acknowledged as a global environmental threat, and poor management and disposal lead to increasing levels in the environment. Of recent concern is the degradation of plastics from macro- to micro- and even to nanosized particles smaller than 100 nm in size. At the nanoscale, plastics are difficult to detect and can be transported in air, soil, and water compartments. While the impact of plastic debris on marine and fresh waters and organisms has been studied, the loads, transformations, transport, and fate of plastics in terrestrial and subsurface environments are largely overlooked. In this Critical Review, we first present estimated loads of plastics in different environmental compartments. We also provide a critical review of the current knowledge vis-a-vis nanoplastic (NP) and microplastic (MP) aggregation, deposition, and contaminant cotransport in the environment. Important factors that affect aggregation and deposition in natural subsurface environments are identified and c...

/pdf/microplastics-and-nanoplastics-in-aquatic-environments-151u4ngf12.pdf

Microplastics and Nanoplastics in Aquatic Environments: Aggregation, Deposition, and Enhanced Contaminant Transport

Microplastics in freshwater systems: A review on occurrence, environmental effects, and methods for microplastics detection.

Microplastics (plastics < 5 mm, including nanoplastics which are < 0.1 μm) originate from the fragmentation of large plastic litter or from direct environmental emission. Their potential impacts in terrestrial ecosystems remain largely unexplored despite numerous reported effects on marine organisms. Most plastics arriving in the oceans were produced, used, and often disposed on land. Hence, it is within terrestrial systems that microplastics might first interact with biota eliciting ecologically relevant impacts. This article introduces the pervasive microplastic contamination as a potential agent of global change in terrestrial systems, highlights the physical and chemical nature of the respective observed effects, and discusses the broad toxicity of nanoplastics derived from plastic breakdown. Making relevant links to the fate of microplastics in aquatic continental systems, we here present new insights into the mechanisms of impacts on terrestrial geochemistry, the biophysical environment, and ecotoxicology. Broad changes in continental environments are possible even in particle-rich habitats such as soils. Furthermore, there is a growing body of evidence indicating that microplastics interact with terrestrial organisms that mediate essential ecosystem services and functions, such as soil dwelling invertebrates, terrestrial fungi, and plant-pollinators.

Therefore, research is needed to clarify the terrestrial fate and effects of microplastics. We suggest that due to the widespread presence, environmental persistence, and various interactions with continental biota, microplastic pollution might represent an emerging global change threat to terrestrial ecosystems.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/gcb.14020

Microplastics as an emerging threat to terrestrial ecosystems

The global increase in plastic production has led to growing concern about the environmental impacts of plastics and their degradation products. Microplastics have been extensively observed and studied in the marine environment but little is known about their presence and abundance in freshwater environments. Although rivers are recognised as a significant source of microplastics to the oceans, they are seldom considered in studies of the environmental presence of microplastics and there are no data reported to date on microplastics in UK rivers (or indeed any freshwater bodies). This study aimed to identify and quantify the abundance and types of plastics in the Thames Basin where population densities and sewage inputs are well described. Ten sampling sites on the River Thames and its tributaries were selected, ranging from densely populated, urban areas to sparsely populated, rural areas. Sites are all downstream of sewage treatment works (STWs) serving known populations, allowing correlation between population density with plastic types and abundances found. In addition samples were collected from sites at known distances downstream of STW outfalls, as well as the effluent itself, to try and establish the proportion of plastics directly entering from STWs, and its fate and transport pathways. River sediment and water samples were collected at all sites. Sediment samples were initially searched by eye, followed by flotation and overflowing using ZnCl2 solution. Plastics collected from the sediments were subsequently identified by Raman spectroscopy. Initial observations indicate that coloured and manmade particles are obviously visible in sediments from sites with high population densities compared to few evident manmade particles in sediments from areas with low population densities. Further analysis will allow for correlation of the plastic types and abundance with population density and sewage inputs to understand the distribution of plastics in river systems.

http://nora.nerc.ac.uk/510906/7/N510906PO.pdf

Presence and abundance of microplastics in the Thames River Basin, UK

Microplastic particles in the environment can associate with persistent organic pollutants (POPs) due to the hydrophobic nature of plastics and organic chemicals. PBDEs (polybrominated diphenyl ethers) are widely used as flame-retardants in products such as textiles and soft furnishings, with the potential to leach into the environment and be associated with microplastics. If ingested, the gut environment of an organism may favour desorption of adsorbed chemicals due to gut condition. Therefore the ingestion of microplastic particles has implications for uptake and bioaccumulation of these chemicals. Furthermore the presence of microplastics and chemicals in the gut of an organism can also influence the gut environment itself. Gut microbiomes are known to hold a vital role in host metabolism, nutrition and immunity and as such understanding the influence of chemicals and microplastics on the gut microbiota is key.

Ingestion of microplastics by the chironomid Chironomus sancticaroli and effects on the microbiome in the presence of PBDEs

Biosolids are the solid by-product of the wastewater treatment system. They are regularly applied to agricultural land in the UK to fertilize and increase crop yields, but they have been shown to contain high concentrations of microplastics. Here we sampled a selection of agricultural soils in the Southeast of England which had received or never received biosolid treatment. Sites were sampled on two occasions in the summer and winter. Microplastic (MP) numbers were high in both the biosolid treated fields (874 MP/kg) and the untreated fields (664 MP/kg) and a wide variety of polymers were found across sites. However, there was a lack of significant difference between treated and untreated soils. This suggests the influence of other microplastic sources e.g. agricultural plastic and general littering, and external conditions e.g. farm management and rainfall. Microplastic concentrations were higher in the summer suggesting that erosion, runoff, and wind transport may be removing microplastics from these systems. The dynamic nature of the agricultural soils may result in them becoming a vector for microplastics into the wider environment. The high variability in results seen here highlights the complexity of microplastic concentrations in heterogeneous agricultural soils. This study suggests that biosolids, whilst are likely a contributor, are not the sole source of microplastics in agricultural soils. Further research is required to determine source and sink dynamics in these systems. Understanding the sources of microplastic contamination in soils is imperative for future mitigation strategies to be effective.

/pdf/agricultural-soils-and-microplastics-are-biosolids-the-3etgej6z.pdf

Agricultural soils and microplastics: Are biosolids the problem?

Bioaccumulation and gut microbiome response in the great pond snail Lymnaea stagnalis exposed to PBDEs in the presence and absence of nylon microplastics

https://centaur.reading.ac.uk/104656/1/SSRN-id3998993.pdf

Alice A. Horton

Papers

Presence and abundance of microplastics in the Thames River Basin, UK

Ingestion of microplastics by the chironomid Chironomus sancticaroli and effects on the microbiome in the presence of PBDEs

Agricultural soils and microplastics: Are biosolids the problem?

Bioaccumulation and gut microbiome response in the great pond snail Lymnaea stagnalis exposed to PBDEs in the presence and absence of nylon microplastics

Accumulation of Nylon Microplastics and Polybrominated Diphenyl Ethers and Effects on Gut Microbial Community Of Chironomus Sancticaroli