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Issue 03/2019

Highlights: Toys Injection Moulding Basics: Microplastics Mind the right terms Captured CO2

Basics Plastic

Basics Plastic microparticles Small particles of plastic were first reported in marine environments in the early 1970s. However, it wasn’t until the term ‘microplastics’ was coined in 2004 that the issue started to generate significant attention. What are microplastics? Plastic particles smaller than 5 millimetres are generally considered to be microplastic. ‘Primary’ microplastics are purposely made this size. However, most are ‘secondary’ microplastics derived from the degradation and fragmentation of larger plastic items. Microbeads used in personal care products, such as facial cleansers are a well-known example of primary microplastics. Secondary microplastics are often fibres originating from the wear and laundering of clothing. Another major source of secondary microplastics is vehicles on the road, where normal wear and tear of tyres and plastic components of the vehicles contribute as well as wear of paints from road markings. Uncontrolled plastic waste and litter also break down into microplastics over time through weathering. Microplastics frequently end up in the ocean. Secondary microplastics are often swept there directly during rainfall, or, like primary microplastics, which are designed to be washed into sewers, eventually make it their way via wastewater treatment systems where they are not captured due to their small size. Microplastics downunder Scientists at Scion (Rotorua, New Zealand) and the University of Canterbury (Christchurch, New Zealand) have been identifying, quantifying and characterising plastic microparticles in Auckland waterways. Auckland is New Zealand’s largest city with zones of high industry, varying land use, estuaries, two harbours and western and eastern coastlines. Over 170 sediment samples were collected and analysed. In line with international trends, the majority of the microparticles recovered were fibres, likely derived from textiles. Higher counts were observed in samples collected near the discharge of wastewater treatment plants. Infrared spectroscopy of the microparticle polymer type showed the majority of the plastic microparticles to be polyethylene, polyethylene terephthalate and polypropylene. Around 40% were found to be cellulose and regenerated cellulose [1]. Effects of microplastics In the ocean, microplastics can be ingested all along the food chain up to shellfish and fish. This can cause physical damage such as obstructions or abrasions and potentially transfer plastic additives such as phthalates. The long-term effects of microplastics on humans is still unknown. However, it is believed that ingested microplastics larger than 150 microns (the size of fine sand grains) will pass through the body without any issues. Particles smaller than this can pass through the gut wall and travel to different parts of the body. The main ways microplastics are consumed by humans are through seafood, including salt, or drinking water and breathing in of household air (or dust). Expectations of public, industry and government Many countries have implemented policies to ban plastic microbeads and reduce single use plastics such as plastic bags. However, as only a portion of microplastics originate Plastic and microplastics on a Caribbean beach from these items (the major sources being synthetic textiles, tyres, city dust, paint…), expectations of a quick fix are misguided. Bioplastics as a solution? Substituting with marine biodegradable polymers is touted as one potential solution to the microplastic problem. Unfortunately, the situation in not that simple. Some polyhydroxyalkanoates (PHA) have been shown to be marine biodegradable, however the estimated lifetime of objects made from PHA in a marine environment still range from 1 to 5 years. Further, the impact of the PHA microparticles on marine organisms within this period is 56 bioplastics MAGAZINE [03/19] Vol. 14

By: Jamie Bridson and Kate Parker Biopolymers and Chemical Technologies Scion Rotorua, New Zealand still unknown. As reported by Francesco Degli Innocenti in Bioplastic Magazine Vol.14/1, biodegradability reduces the risk, but ultimately mitigation using bioplastics should be based on sound impact and risk assessment methodology. Oxo-degradable plastics are sometimes suggested as another possible solution. However, oxo-degradable plastics are designed to fragment into microplastics meaning they actually contribute to the problem. Turning the tide A wide range of clean-up strategies have been proposed by various groups from community litter collections to vast ocean clean ups. However, preventing microplastics being generated or reaching the environment in the first place are better solutions. Improved waste management, circular Join us at the 14th European Bioplastics Conference The leading business forum for the bioplastics industry economy principles and new materials will all form part of the solution to this challenging but extremely important issue. Acknowledgements This work was funded by the New Zealand Ministry for the Environment through the Waste Minimisation Fund and Packaging Council of New Zealand (PAC.NZ). Work was supported by collaborators at Auckland Council, Watercare and the University of Auckland. [1] id=1&objectid=12164041 3/4 December 2019 Titanic Chaussee Hotel Berlin, Germany @EUBioplastics #eubpconf REGISTER NOW! For more information email: bioplastics MAGAZINE [03/19] Vol. 14 57

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