Seite - 267 - in Freshwater Microplastics - Emerging Environmental Contaminants?

• Howshould standardizationofmonitoringmethods look like? • How can ecotoxicological test designs be adopted for an assessment of com- bined chemical andmechanical effects? • What are the relevant sources andpathways into the environment? • Whichmeasures can reduceMPentry into the environment? However, the list of questions could be continued far beyond the one above – especially with regard to different perspectives as human toxicology, drinking water supply, etc. exceeding the scope of this freshwater-related chapter. Never- theless, it emphasizes theneedof interdisciplinarycooperation toaddress the issue of freshwater (micro)plastics. 4 Conclusions This chapter provided a rough overview of the existing regulation instruments developed at international, regional, and national levels to address freshwater (micro)plastics. While several regulations address plastics, concrete regulations onmicroplastics – especiallywith regard to freshwater systems– are rare.Hence, we discussed possible reasons for that and formulated a list of questions to be answeredwith priority. Despitemanyopenquestions,wewant to conclude that: • In our point of view, regulation of freshwater (micro)plastics is urgently required. • Animportant step toward themanagementofenvironmental (micro)plasticshas been accomplishedbyawareness raising in society andpolicy. • International and intergovernmental bodies already discussmeasures to reduce environmental plastics (e.g.,UN,G7,WorldBank,WorldEconomicForum) • So far, policy-makers integrated the (micro)plastic issue into a few regulatory directives on international andnational level. • These regulations concern diverse fields of policy (e.g., chemical regulation, wastemanagement,water resourcemanagement). • Environmental policy provides a long list of instruments, which might be adopted to develop furthermanagement options for the issueofMP. Nevertheless, further research should be promoted to fill current knowledge gaps. The compilation of challenges for regulation andmanagement as presented in Sect. 3 highlights themost important needs from the perspective of freshwater monitoring.Thus, the key issues to be tackled in a systematic approach are: • Microplastics are a heterogeneous groupof pollutants. • Hence, adefinitionof regulatory (sub)groups is as important as thedefinitionof MPs itself in order to definemanagement optionsmore precisely. • AsMPsaremainlyderivedfromlargerplastic items, itsmanagementneedstobe closely linked to the regulationof plastic production, consumption, and litter. FreshwaterMicroplastics:Challenges forRegulation andManagement 267