Primary and Secondary Plastic Particles Exhibit Limited Acute Toxicity but Chronic Effects on Daphnia magna

Abstract

Nanoplastics (NPs; <0.1 μm) are speculated to be a bigger ecological threat due to their predicted wider distribution, higher concentrations, and bioavailability. Primary NPs are manufactured to be that size, while secondary NPs originate from fragmentation of bigger debris. To date, the long-term impact of NPs in freshwater systems, particularly secondary NPs, is not well-understood. Thus, we employed a freshwater invertebrate, Daphnia magna, to investigate the chronic effects of model primary NPs, fluorescent polystyrene nanospheres (PS-NPs; 20 nm), and water leachate of weathered single-use plastics that contained micro-and nanosized particles. In experiment 1, parent Daphnia (F0) were exposed to 1 and 50 mg/L PS-NPs until the production of the neonates (F1) followed by a two-generation recovery. PS-NPs were mainly detected in the intestine and brood chamber in F0 and transferred to F1 and F2. PS-NPs significantly decreased the appendage curling and heartbeat rate in F0 and reduced reproduction in F2. In experiment 2, the plastic leachate also reduced the appendage curling rate but increased growth and reproduction. The results suggest that the acute toxicity of primary and secondary plastic particles is low even at high concentrations, but their chronic and sublethal effects should not be overlooked.

Physisorption and Chemisorption Mechanisms Influencing Micro (Nano) Plastics-Organic Chemical Contaminants Interactions: A Review

“…Although plastics have significantly contributed to improvements in healthcare industry, building construction, electronics and contemporary human life in general, burgeoning build-up of improperly managed plastic wastes has raised concerns over their long-term health and ecotoxicological risks (Fahrenkamp-Uppenbrink, 2018;Ha and Yeo, 2018;Lei et al, 2018;Yu et al, 2018;Barletta et al, 2019;Besseling et al, 2019;Savoca et al, 2019;Adika et al, 2020;Bakir et al, 2020;Ding et al, 2020;Everaert et al, 2020;Fred-Ahmadu et al, 2020a;Fred-Ahmadu et al, 2020b;Lu et al, 2020;Na et al, 2020;Wilcox et al, 2020;Wong et al, 2020;Yu and Chan, 2020). Microplastics (MPs; 0.1 µm-5 mm) and nanoplastics (NPs; <0.1 µm) are ubiquitous and can accumulate in marine and freshwater ecosystems and exposed organisms, carrying chemical contaminants that are capable of posing considerable threats to human health, environment and aquatic life (de Souza Machado et al, 2018;Hartmann et al, 2019;Cole et al, 2020;Xu et al, 2020). Micro (nano) plastics (MNPs) are generally speculated to have increased environmental and health threats to marine organisms primarily due to their small size, predicted ubiquitousness, direct and indirect intake of plastic particles, bioavailability and enhanced concentrations of sorbed toxic chemicals (Setälä et al, 2018;Yu et al, 2018;Cole et al, 2020;Fred-Ahmadu et al, 2020a;Fred-Ahmadu et al, 2020b;Xu et al, 2020;Yu and Chan, 2020).…”

“…Microplastics (MPs; 0.1 µm-5 mm) and nanoplastics (NPs; <0.1 µm) are ubiquitous and can accumulate in marine and freshwater ecosystems and exposed organisms, carrying chemical contaminants that are capable of posing considerable threats to human health, environment and aquatic life (de Souza Machado et al, 2018;Hartmann et al, 2019;Cole et al, 2020;Xu et al, 2020). Micro (nano) plastics (MNPs) are generally speculated to have increased environmental and health threats to marine organisms primarily due to their small size, predicted ubiquitousness, direct and indirect intake of plastic particles, bioavailability and enhanced concentrations of sorbed toxic chemicals (Setälä et al, 2018;Yu et al, 2018;Cole et al, 2020;Fred-Ahmadu et al, 2020a;Fred-Ahmadu et al, 2020b;Xu et al, 2020;Yu and Chan, 2020).…”

“…Plastics comprise chemical additives that are usually not chemically bonded to the plastic particles molecules and are likely to get leached into the surrounding aqueous medium Wright and Kelly, 2017). Several additives, including UV-stabilizers, plasticizers, antioxidants, and flame retardants contained in plastics have been widely reported (Jang et al, 2017;Tanaka et al, 2019;Fred-Ahmadu et al, 2020a;Fred-Ahmadu et al, 2020b;Jeong and Choi, 2020;Xu et al, 2020). Chemical additives such as esters of phthalic acids, which are commonly known as phthalate esters (PAEs) are ubiquitous, highly toxic, and commercially used as plasticizers for enhancing the durability, flexibility, lightness, and transparency of plastics (Xu et al, 2020;Zhang P. et al, 2019;Hahladakis et al, 2018;Avio et al, 2017;Kang et al, 2017).…”

Long Term Exposure to Virgin and Recycled LDPE Microplastics Induced Minor Effects in the Freshwater and Terrestrial Crustaceans Daphnia magna and Porcellio scaber

“…For D. magna , mortality [ 61 ], decreased reproduction [ 61 , 62 , 63 , 64 ] decreased growth and population growth rate [ 62 ] has been shown for virgin 1–6 µm MP spheres (polymeric composition not reported, PE and PS) from concentrations as low as 0.1 mg/L [ 62 ]. Similarly, adverse effects on Daphnia longevity, growth, reproduction [ 65 , 66 ] and physiological endpoints (heart and appendage beat rate) [ 44 ] have also been demonstrated upon PS nanosphere exposures. Physical properties of the MP are essential regarding inducing of adverse effects [ 46 ] and facilitated MP uptake by various routes (orally, anally) by D. magna (or other organisms) and moreso, inhibited egestion may be one of the most important triggers leading to adverse effects, especially over a longer exposure period.…”

“…Again, these studies have been conducted on virgin plastics with a few exceptions in studied MP from consumer products. Xu et al [ 44 ] showed exposure to post-consumer mixed plastic leachate containing differently sized MP did not affect survival of D. magna , but increased growth and reproduction that was attributed to hormesis and the potential role of plastic additives. Schür et al [ 45 ] showed irregular PS MP to affect D. magna life-history endpoints differently from natural kaolin particles.…”