Physical and chemical effects of conventional microplastic glitter versus alternative glitter particles on a freshwater plant (Lemnaceae: Lemna minor).

Glitters are primary microplastics which are directly littered into the environment, yet the ecological effects have seldom been tested. When microplastics enter the environment, their physical presence and chemical leachate may alter the physiology of primary producers. Glitter can be composed of plastic or natural and/or biodegradable materials, often with additives. Three experiments were run for 14 days to separate chemical and physical effects of different types of glitter: polyethylene terephthalate (PET), biodegradable modified regenerated cellulose (MRC), synthetic mica, and a natural particle control (kaolinite) on several physical characteristics of Lemna minor (common duckweed). L. minor was exposed to either fresh (chemical and physical effects), leachate from glitter (chemical) or aged glitter (physical). Overall, there was little effect of PET, synthetic mica, kaolinite or of any aged glitter. High concentrations of fresh MRC glitters, however, decreased root length, biomass and chlorophyll content of L. minor. Some of these effects were also present when exposed to leachate from MRC glitters, but were less pronounced. Elemental analysis revealed the presence of metals in MRC glitters which may explain these responses. Short-term ecotoxicity of biodegradable glitters can arise due to their physical and chemical properties, but may lessen over time as their surface coating degrades.

Disposable e-cigarettes and cigarette butts alter the physiology of an aquatic plant Lemna minor (Lemnaceae).

Cigarette butts are one of the most littered single-use plastic items worldwide and can have ecotoxicological effects. e-Cigarettes (or 'vapes') have gained popularity globally as an alternative to tobacco-based cigarettes in recent years. The increased availability of disposable e-cigarettes has resulted in a rise in their littering, presenting a complex form of e-waste in the environment, yet the environmental impacts of littered e-cigarettes are largely unknown. Here Lemna minor (common duckweed) was used as a model organism to understand the effects of smoked cigarettes, vaped e-cigarettes or e-liquid. Growth-related physiological responses were measured (biomass, root development and frond chlorophyll content). After 14 days of exposure to cigarette butts there was an increase of all measured growth variables. On the contrary, exposure to e-cigarettes or e-liquid caused a decrease in root length, biomass and frond number relative to controls. The significant deviations from control conditions suggest that the presence of either cigarette butts, e-cigarettes or e-liquid caused stress to the model plant which could indicate disruption of aquatic ecosystems at the primary producer level. Disposable vapes pose a novel threat to aquatic ecosystems and it would be prudent to prevent them from becoming the next top litter item.

Cigarette butts in two urban areas from Brazil: Links among environmental impacts, demography and market.

Environmental impacts are currently linked to smoking cigarette behavior, as cigarette butts (CBs) represent the most common litter item in natural areas. Despite this, even the best ranked Brazilian cities, in terms of urban cleaning, have no information about urban littered CBs. Thus, CBs were monitored in Santos and Niterói cities, aiming to assess contamination, Cigarette Butt Pollution Index (CBPI) and the illegal market size. CBs were collected in 36 walkways considering different land usage types and urban density levels. The CBPI was calculated, and brands were used to identify the size of the illegal market. CBs contamination in Santos (0.25 CBs/m2) was three times higher than Niterói (0.08 CBs/m2) and their occurrence and distribution presented no relationship with land usage types and urban population densities levels. CBPI = 17.6 was severe and the highest so far reported. A total of 28 cigarette brands were found both studied cities. Further, illegal cigarette consumption in Santos and Niteroi was estimated, based on brands of collected CBs, at 25.2% and 36.8%, respectively. Such data may be valuable for implementation of logistic reverse actions seeking to environmentally sustainable and socially resilient cities. Cigarette consumption threatens human life and the environment, and tobacco companies should be accountable for the pollution they generate.

Effects of cigarette butts on marine keystone species (Ulva lactuca L. and Mytilus edulis L.) and sediment microphytobenthos.

Outdoor mesocosms with constantly flowing natural seawater were used to test the effects of littered cigarette butts on the filter feeder Mytilus edulis (blue mussel), the macroalga, Ulva lactuca (sea lettuce) and sediment microphytobenthos in a semi-natural marine setting. Either conventional, cellulose acetate, or biodegradable, cellulose, smoked cigarette butts were added at densities of 0.25 or 1 butt L-1. The clearance rates of mussels exposed to 1 butt L-1 of cellulose acetate butts were three times less than the controls. The growth of U. lactuca was not measurably affected by cigarette butts, however the sediment chlorophyll content was significantly less in mesocosms exposed to 0.25 and 1 butt L-1 of cellulose acetate butts. These effects occurred despite constant replacement of seawater indicating how hazardous conventional cigarette butts are to marine life. Biodegradable cellulose cigarette butts had minimal effects on the measured variables but should still not be discarded as litter.

All that glitters is litter? Ecological impacts of conventional versus biodegradable glitter in a freshwater habitat.

Biodegradable plastics are becoming increasingly popular due to global concerns about plastic pollution. In this study, the impacts of glitter manufactured of conventional, non-biodegradable polyethylene terephthalate (PET) versus glitter of alternative materials (modified regenerated cellulose (MRC), mica or synthetic mica) on the biodiversity and ecosystem functioning of freshwater, lotic habitats were compared using a semi-natural mesocosm experiment. After 36 days, there was no effect of glitter on overall assemblage structure or diversity indices, however there was a two-fold increase in the abundance of New Zealand mud snails (Potamopyrgus antipodarum) in response to MRC glitter. In addition, the root length of common duckweed (Lemna minor) and phytoplankton biomass (based on chlorophyll content) were significantly reduced by exposure to any type of glitter. On the contrary, the chlorophyll content in the sediment (indicating microphytobenthos biomass) was significantly greater in those exposed to synthetic mica glitter. Organic matter content of sediment did not differ amongst any of the treatments. However initially, on days 8 and 15, NO32- concentration in the control treatment were significantly greater than in all glitter treatments, but this observation disappeared over time. Overall, results indicate that both conventional and alternative glitters can cause ecological impacts in aquatic ecosystems.

Smoked cigarette butt leachate impacts survival and behaviour of freshwater invertebrates.

Smoked cigarette filters a. k.a. "butts", composed of plastic (e.g. cellulose acetate) are one of the world's most common litter items. In response to concerns about plastic pollution, biodegradable cellulose filters are being promoted as an environmentally safe alternative, however, once smoked, both contain toxins which can leach once discarded. The impacts of biodegradable butts as littered items on the receiving environment, in comparison with conventional butts has not yet been assessed. A freshwater mesocosm experiment was used to test the effects of leachate from smoked cellulose acetate versus smoked cellulose filters at a range of concentrations (0, 0.2, 1 and 5 butts L-1) on the mortality and behaviour of four freshwater invertebrates (Dreissena polymorpha, Polycelis nigra, Planorbis planorbis and Bithynia tentaculata). Leachate derived from 5 butts L-1 of either type of filter caused 60-100% mortality to all species within 5 days. Leachate derived from 1 butt L-1 of either type resulted in adults being less active than those exposed to no or 0.2 butts L-1 leachate. Cigarette butts, therefore, regardless of their perceived degradability can cause mortality and decreased activity of key freshwater invertebrates and should always be disposed of responsibly.

Effects of Microplastics in Soil Ecosystems: Above and Below Ground.

Environmental contamination by microplastics is now considered an emerging threat to biodiversity and ecosystem functioning. Soil ecosystems, particularly agricultural land, have been recognized as a major sink of microplastics, but the impacts of microplastics on soil ecosystems (e.g., above and below ground) remain largely unknown. In this study, different types of microplastics [biodegradable polylactic acid (PLA)], conventional high-density polyethylene (HDPE), and microplastic clothing fibers were added to soil containing the endogeic Aporrectodea rosea (rosy-tipped earthworm) and planted with Lolium perenne (perennial ryegrass) to assess the biophysical soil response in a mesocosm experiment. When exposed to fibers or PLA microplastics, fewer seeds germinated. There was also a reduction in shoot height with PLA. The biomass of A. rosea exposed to HDPE was significantly reduced compared to control samples. Furthermore, with HDPE present there was a decrease in soil pH. The size distribution of water-stable soil aggregates was altered when microplastics were present, suggesting potential alterations of soil stability. This study provides evidence that microplastics manufactured of HDPE and PLA, and synthetic fibers can affect the development of L. perenne, health of A. rosea and basic, but crucial soil properties, with potential further impacts on soil ecosystem functioning.

Microplastics Affect the Ecological Functioning of an Important Biogenic Habitat.

Biological effects of microplastics on the health of bivalves have been demonstrated elsewhere, but ecological impacts on the biodiversity and ecosystem functioning of bivalve-dominated habitats are unknown. Thus, we exposed intact sediment cores containing European flat oysters (Ostrea edulis) or blue mussels (Mytilus edulis) in seawater to two different densities (2.5 or 25 µg L-1) of biodegradable or conventional microplastics in outdoor mesocosms. We hypothesized that filtration rates of the bivalves, inorganic nitrogen cycling, primary productivity of sediment dwelling microphytobenthos, and the structure of invertebrate benthic assemblages would be influenced by microplastics. After 50 days, filtration by M. edulis was significantly less when exposed to 25 µg L-1 of either type of microplastics, but there were no effects on ecosystem functioning or the associated invertebrate assemblages. Contrastingly, filtration by O. edulis significantly increased when exposed to 2.5 or 25 µg L-1 of microplastics, and porewater ammonium and biomass of benthic cyanobacteria decreased. Additionally the associated infaunal invertebrate assemblages differed, with significantly less polychaetes and more oligochaetes in treatments exposed to microplastics. These findings highlight the potential of microplastics to impact the functioning and structure of sedimentary habitats and show that such effects may depend on the dominant bivalve present.

Effects of microplastics on European flat oysters, Ostrea edulis and their associated benthic communities.

Plastic pollution is recognised as an emerging threat to aquatic ecosystems, with microplastics now the most abundant type of marine debris. Health effects caused by microplastics have been demonstrated at the species level, but impacts on ecological communities remain unknown. In this study, impacts of microplastics on the health and biological functioning of European flat oysters (Ostrea edulis) and on the structure of associated macrofaunal assemblages were assessed in an outdoor mesocosm experiment using intact sediment cores. Biodegradable and conventional microplastics were added at low (0.8 µg L(-1)) and high (80 µg L(-1)) doses in the water column repeatedly for 60 days. Effects on the oysters were minimal, but benthic assemblage structures differed and species richness and the total number of organisms were ∼1.2 and 1.5 times greater in control mesocosms than in those exposed to high doses of microplastics. Notably, abundances of juvenile Littorina sp. (periwinkles) and Idotea balthica (an isopod) were ∼2 and 8 times greater in controls than in mesocosms with the high dose of either type of microplastic. In addition, the biomass of Scrobicularia plana (peppery furrow shell clam) was ∼1.5 times greater in controls than in mesocosms with the high dose of microplastics. This work indicates that repeated exposure to high concentrations of microplastics could alter assemblages in an important marine habitat by reducing the abundance of benthic fauna.

Effects of conventional and biodegradable microplastics on a marine ecosystem engineer (Arenicola marina) and sediment nutrient cycling.

Effects of microplastic pollution on benthic organisms and ecosystem services provided by sedimentary habitats are largely unknown. An outdoor mesocosm experiment was done to realistically assess the effects of three different types of microplastic pollution (one biodegradable type; polylactic acid and two conventional types; polyethylene and polyvinylchloride) at increasing concentrations (0.02, 0.2 and 2% of wet sediment weight) on the health and biological activity of lugworms, Arenicola marina (Linnaeus, 1758), and on nitrogen cycling and primary productivity of the sediment they inhabit. After 31 days, A. marina produced less casts in sediments containing microplastics. Metabolic rates of A. marina increased, while microalgal biomass decreased at high concentrations, compared to sediments with low concentrations or without microplastics. Responses were strongest to polyvinylchloride, emphasising that different materials may have differential effects. Each material needs to be carefully evaluated in order to assess their risks as microplastic pollution. Overall, both conventional and biodegradable microplastics in sandy sediments can affect the health and behaviour of lugworms and directly or indirectly reduce primary productivity of these habitats.

Impacts of discarded plastic bags on marine assemblages and ecosystem functioning.

The accumulation of plastic debris is a global environmental problem due to its durability, persistence, and abundance. Although effects of plastic debris on individual marine organisms, particularly mammals and birds, have been extensively documented (e.g., entanglement and choking), very little is known about effects on assemblages and consequences for ecosystem functioning. In Europe, around 40% of the plastic items produced are utilized as single-use packaging, which rapidly accumulate in waste management facilities and as litter in the environment. A range of biodegradable plastics have been developed with the aspiration of reducing the persistence of litter; however, their impacts on marine assemblages or ecosystem functioning have never been evaluated. A field experiment was conducted to assess the impact of conventional and biodegradable plastic carrier bags as litter on benthic macro- and meio-faunal assemblages and biogeochemical processes (primary productivity, redox condition, organic matter content, and pore-water nutrients) on an intertidal shore near Dublin, Ireland. After 9 weeks, the presence of either type of bag created anoxic conditions within the sediment along with reduced primary productivity and organic matter and significantly lower abundances of infaunal invertebrates. This indicates that both conventional and biodegradable bags can rapidly alter marine assemblages and the ecosystem services they provide.