Seite - 287 - in Freshwater Microplastics - Emerging Environmental Contaminants?

interventions, including bioplastics, extended producer responsibility, and novel business approaches. Green Chemistry as a Biological Material Bioplastic has been in production sinceHenryFord’s soybeancar in the1930s,made fromsoy-basedphenolic resin, which he bashedwith a sledgehammer to demonstrate its resilience, but theWWII demandforacheap,better-performingmaterialinducedhimtochosepetroleum-based plastic.Today,bioplasticsareviewedwithnewinterest.Theseplant-basedplasticsare considered a means to create a more reliable and consistently valued resource, decoupled from fossil fuels. The Bioplastic FeedstockAlliance, createdwith wide industryallianceandsupportfromtheWorldWildlifeFund(WWF),intendstoreplace fossil fuelswith renewable carbon fromplants, representingnonet increase inGHG emissions.Referredtoas[the]“bioeconomy,”thesecompaniesenvisionbioplasticsas “reducing thecarbon intensityofmaterials suchas thoseused inpackaging, textiles, automotive, sportsequipment,andother industrialandconsumergoods”[88]. It is important todistinguishbiodegradablefrombio-basedplastics.Bioplastic is the loosely defined catch-all phrase that describes plastic from recent biological materials,which includes truebiodegradablematerialsandnonbiodegradablepoly- mers that are plant based. While the label “biodegradable” has a strict ASTM standard and strict guidelines for usage in advertising, the terms bioplastic, plant based, andbio baseddonot.Despite all of the leafy greenery in labeling for these bioplastics, it is still the samepolymer thatwouldotherwisehavecomefromfossil fuels. The biodegradability of bio-based and biodegradable plastics will vary widely basedon thebiological environmentwhere degradationmayoccur. Poly-lactic acid (PLA) is a compostable consumer bio-based plastic requiring a large industrial composting facility that’s hot, wet, and full of compost-eating microbes, unlike a backyardcompostingbin.Poly-hydroxy-alkanoate(PHA),madefromtheoff-gassing of bacteria, is amarine-degradable polymer (ASTM7081), but rates of degradation varywith temperature, depth, andavailablemicrobial communities [89]. PHAandPLAareboth recyclable andcompostable, but how thesematerials are manageddependsonavailable infrastructure.While recyclingcouldbeenergetically more favorable than composting, it may not be practical because of sorting and cleaning requirements. Kale et al. point out the lack of formal agreement between stakeholders (industry, wastemanagement, government) about the utility of biode- gradableplasticsand theirdisposal [90],but thecompostabilityofbioplasticpackag- ingmaterialscouldbecomeaviablealternativeifsocietyasawholewouldbewilling to address the challenges of cradle-to-grave life of compostable polymers in food, manure, or yard waste composting facilities. The industries that make bioplastic polymers recognize these challenges and therefore their limited applications. PHA isidealtobeusedwhereyouneedfunctionalbiodegradation,suchassomeagriculture and aquaculture applications,where a part has a job todo in the environment but it wouldbeeither impracticalorverycostly torecover (Metabolix,personalcommuni- cation). Also, many single-use throwaway applications may be replaced by PHA, includingstrawsorthepolyethyleneliningonpapercups(MangoMaterials,personal Microplastic:WhatAre theSolutions? 287