Microplastics, Their Toxic Effects on Living Organisms in Soil Biota and Their Fate: An Appraisal
Abstract
Microplastics are miniature plastic fragments that originate as a result of the advancement of commercial products as well as the breakdown of bigger plastics. Microplastics have been identified as a serious global environmental issue due to its poor waste management. This review covers the impact of microplastics on the soil ecosystem, their transit behaviour, and their impact on numerous organisms. The impact of microplastics on soil animals and plants, is influenced by the size, shape, and concentration of microplastics in the soil. Microplastic has been found in a variety of soil types, including agricultural, industrial, and coastal soils. Plastic particles in soil have increased, posing a major threat to soil ecosystem functioning, including the soil microbial population, nitrogen cycle, and higher organisms. The current review highlights and assimilates the findings of other scientists so that it can serve as a resource for readers and scientists dealing with microplastics, including toxicity, risk assessment in the environment, and microplastic treatment options.
... MPs and NPs fragments released in earthworm casts are coated with biofilms containing soil biota as well as inorganic and organic soil-derived molecules. These biofilms, also known as ecocoronas, can alter the shape, size, density, and surface charge of MPs and NPs, affecting their mobility, bioavailability, degradation, and toxicity (Bhattacharyya et al., 2022;Galloway et al., 2017). ...
... An experiment in a laboratory setting found that earthworms exposed to MPs and NPs exhibited lower biomasses and denser burrow walls compared to a control group (Huerta Lwanga et al., 2017). Notably, the interaction between earthworms and MPs enhances soil properties, as certain polymers are used as soil conditioners to improve water retention, infiltration, and soil stabilization (Bhattacharyya et al., 2022;Ng et al., 2018). ...
In the aquatic food chain, microplastics (MPs) are ubiquitous. The presence of microplastics in water and the physicochemical properties of water can likely affect aquatic biota. The physicochemical environment determines the structure of zooplankton community. The pollution of aquatic ecosystems by microplastics is widespread. Aquatic zooplankton and various larger animal species (reptiles, birds, mammals) have been affected due to consumption of plastic fibres through food chains. Concentration of aquatic pollution increasing day by day with microplastics resulting from urban sewage discharges, industrial effluents, and anthropogenic activities. Microplastics are absorbed by fish that consume plankton, which is amplified by other organisms. In total, we have surveyed 57 research papers on microplastics in zooplankton. Zooplankton diversity of an area can be used to assess water contamination, particularly nutrient-rich eutrophication of that particular area. Microplastics may interfere with the production of endocrinological hormones in humans. In future, this will be a great hazard to human beings. Microplastic (<5mm in length) may be polyethene or polypropylene or polystyrene in nature and may be white or red or blue in colour. The study examines the water, the importance of zooplankton to the aquatic ecosystem, and the microplastic concentration report. As a result of this assessment, national and international authorities will be able to assess a range of stakeholders, make decisions and build policies that will benefit many stakeholders.
Plastic debris sized from 0.33 to 5 mm or so-called microplastic is an abundant environmental pollutant found worldwide in various ecosystems. The contamination has been threatening animals such as fish, wild birds, domesticated poultry, and waterfowls. This preliminary research aimed to reveal the evidence of microplastic contamination in domesticated duck to prove that plastic contamination has spread massively and depicts how far the local duck ingests microplastic. Total 25 duck samples were collected from local duck intensive husbandry in five cities, i.e., Semarang and Pati (coastal area), Salatiga (lowland area), and Temanggung and Magelang (highland area). Duck intestinal tract samples were collected and were further digested using 10 N KOH at 60–80 °C for 24 h. The mixture was then collected into vial tubes and was centrifuged to get the pellet. The microplastic identification was conducted using a stereo microscope based on its size and shape. Based on the observation result, microplastic debris in the form of the filament was 49, 39, and 27 per individual in the duck sample from Salatiga, Semarang, and Magelang, respectively. The ingestion of plastic may come from duck feed, such as rough fish (mainly were obtained from the Java Sea) and water. This finding is essential to disseminate since microplastic contamination can be transferred from animals to humans and threaten health. Also, this result can contribute to policymakers deciding on plastic reduction.
The plastic mulch films used in agriculture are considered to be a major source of the plastic residues found in soil. Mulching with low-density polyethylene (LDPE) is widely practiced and the resulting macro- and microscopic plastic residues in agricultural soil have aroused concerns for years. Over the past decades, a variety of biodegradable (Bio) plastics have been developed in the hope of reducing plastic contamination of the terrestrial ecosystem. However, the impact of these Bio plastics in agroecosystems have not been sufficiently studied. Therefore, we investigated the impact of macro (around 5 mm) and micro (<1 mm) sized plastic debris from LDPE and one type of starch-based Bio mulch film on soil physicochemical and hydrological properties. We used environmentally relevant concentrations of plastics, ranging from 0 to 2% (w/w), identified by field studies and literature review. We studied the effects of the plastic residue on a sandy soil for one month in a laboratory experiment. The bulk density, porosity, saturated hydraulic conductivity, field capacity and soil water repellency were altered significantly in the presence of the four kinds of plastic debris, while pH, electrical conductivity and aggregate stability were not substantially affected. Overall, our research provides clear experimental evidence that microplastics affect soil properties. The type, size and content of plastic debris as well as the interactions between these three factors played complex roles in the variations of the measured soil parameters. Living in a plastic era, it is crucial to conduct further interdisciplinary studies in order to have a comprehensive understanding of plastic debris in soil and agroecosystems.
Whereas the dramatic environmental impact of plastic waste rightfully receives considerable attention by scientists, policy makers and public in general, the human health impact of micro- and nanoplastics contamination of our food and beverages remains largely unknown. Indeed, most studies aim at understanding the environmental impact rather than the human health impact of a possible exposure to micro- and nanoplastics. In addition, these papers generally lack a methodological, standardised approach. Furthermore, some studies focus on the damage to and contamination level of animal species collected from the wild environment, and others investigate the rate and biology of microplastic uptake of animals fed with microplastics in laboratory. This review aims at understanding human exposure. Since there is, with few exceptions, no evidence available on the presence of micro- and nanoplastics in a normal diet, this study takes an indirect approach and analyses peer-reviewed publications since 2010 that document the presence of micro- and nanoplastics in those animals (more than 200 species) and food products that are part of the human food chain and that may thus contribute directly or indirectly to the uptake of micro- and nanoplastics via the human diet. It also addresses the question of the definitions, the methodologies and the quality criteria applied to obtain the reported results. This review suggests that, beyond a few estimations and comparisons, precise data to assess the exact exposure of humans to micro- and nanoplastics through their diet cannot be produced until standardised methods and definitions are available.
Micro- and nano-plastics have widely been recognized as major global environmental problem due to its widespread use and inadequate waste management. The emergence of these plastic pollutants in agroecosystem is a legitimate ecotoxicological concerns for food web exchanges. In agriculture, micro/nano plastics are originated from a variety of different agricultural management practices, such as the use of compost, sewage sludge and mulching. A range of soil properties and plant traits are affected by their presence. With the increase of plastic debris, these pollutant materials have now begun to demonstrate serious implications for key soil ecosystem functions, such as soil microbial activity and nutrient cycling. Nitrogen (N) cycle is key predictor of ecological stability and management in terrestrial ecosystem. In this review, we evaluate ecological risks associated with micro-nano plastic for soil-plant system. We also discuss the consequence of plastic pollutants, either positive or negative, on soil microbial activities. In addition, we systematically summarize both direct and hypothesized implications for N cycling in agroecosystem. We conclude that soil N transformation had showed varied effects resulting from different types and sizes of plastic polymers present in soil. While mixed effects of microplastic pollution on plant growth and yield have been observed, biodegradable plastics have appeared to pose greater risk for plant growth compared to chemical plastic polymers.
Microplastics (MP) are a persistent and silent threat to the environment and are already considered a significant problem in aquatic environments. However, the presence of MP in soils and terrestrial ecosystems has been largely unexplored. Recent research has identified the risk of MP transfer from terrestrial agriculture to the human food chain. Thus, MP should be treated as a future threat to food safety and sustainable agriculture. Several reviews have focused on MP effects within global environmental matrices. However, scant investigations on the disposition, ecological impact and remediation strategies of MP have been reported in case of unexplored soil ecosystems as compared to aquatic ecosystems. Therefore, this review focuses on the contemporary global MP research with respect to research opportunities and related challenges of MP for the soil and terrestrial ecosystem from a Bangladesh perspective.
The issue of microplastic pollution emerged from the marine environment, but the terrestrial environment is estimated to receive annually 4–23 times more plastic wastes. Microplastic pollution in the soil environment has thus begun to elicit great concern. This review summarizes the observed effects of microplastic pollution on soil ecosystems as well as sorption and transport behaviors of microplastics in such environments. Microplastic pollution has been detected in various soils including agricultural/farmland, greenhouse, home garden, coastal, industrial, and floodplain soils. Microplastics affect soil physical and chemical properties, microbial and enzyme activities, and plant growth, and also pose adverse ecotoxicological effects to soil fauna. These effects depend on the concentration, size, and shape of microplastics, as well as soil texture. Microplastics are known to sorb organic and inorganic pollutants, possibly affecting the distribution of these substances in soil. Existing evidence demonstrates the negligible effect of microplastics on bioaccumulation of contaminants in soil fauna. The horizontal and vertical transport of microplastics can be facilitated by soil fauna. Pollutants associated with microplastics may disperse further following the transport of microplastics in soil. This review also highlights perspectives for future research on microplastics in soil.
Microplastics have become a contaminant of increasing concern in soils. Although biodegradable plastics were considered as alternatives of traditional plastics, some evidence showed that biodegradable plastics might produce more microplastics. Until now, the effect of biodegradable microplastics on soil functions and processes, as well as microbial communities is uncertain. Based on high throughput sequencing, enzymatic activity assay and dynamic analysis of soil carbon and nitrogen, we investigated the effects of biodegradable polylactic acid microplastics (PLA MPs) on soil microbiota and related ecological processes under conditions of high or low carbon content. The results showed that PLA MPs had no significant effect on the overall diversity and composition of bacterial communities or related ecosystem functions and processes. However, co-occurrence network analysis revealed that PLA MPs impacted the interactions between constituent species, which might have legacy effect on soil bacterial communities and functions. Our data also revealed that PLA MPs could trade off the priming effect of carbon source. Our results provided an integrated picture in understanding the effects of PLA MPs on soil microbes, properties and ecological functions, which will help to further understand the effects of MPs on terrestrial ecosystems.
Microplastics (MPs) have become a global environmental concern because of their ubiquitous presence. While extensive microplastic researches have focused on the marine environment, pervasive MPs contamination in soil and their detrimental impacts have been largely overlooked. Excessive concentrations of MPs and additives have been found in soil derived from the use of plastic mulches and the application of sewage sludge to fields. They may pose directly or indirectly as adverse effects on flora and fauna. The objectives of this review are (1) to summarize the abundance, sources, and properties of MPs in soil; (2) to analyze combined effects of MPs and various other environmental pollutants on soil system; and (3) to discuss the possible risks posed by MPs to soil biodiversity, food safety and human health. This review will highlight key future research areas for scientists and policymakers, and increase overall understanding of soil MPs pollution and its potential environmental impacts.
Microplastics can affect biophysical properties of the soil. However, little is known about the cascade of events on fundamental levels of terrestrial ecosystems, i.e. starting with the changes in soil abiotic properties and propagating across the various components of soil-plant interactions, including soil microbial communities and plant traits. We investigated here the effects of six different microplastics (polyester fibers, polyamide beads, and four fragment types- polyethylene, polyester terephthalate, polypropylene, and polystyrene) on a broad suite of proxies for soil health and performance of spring onion (Allium fistulosum). Significant changes were observed in plant biomass, tissue elemental composition, root traits, and soil microbial activities. These plant and soil responses to microplastic exposure were used to propose a causal model for the mechanism of the effects. Impacts were dependent on particle type, i.e. microplastics with a shape similar to other natural soil particles elicited smaller differences from control. Changes in soil structure and water dynamics may explain the observed results, in which polyester fibers and polyamide beads triggered the most pronounced impacts on plant traits and function. The findings reported here imply that the pervasive microplastic contamination in soil may have consequences for plant performance, and thus for agroecosystems and terrestrial biodiversity.