Seite - 259 - in Freshwater Microplastics - Emerging Environmental Contaminants?

However, ecotoxicity-derivedgroups are not necessarily suitable for regulation purposes:As eachMPparticle has unique physicochemical properties (individual polymers,additives, size, shape,etc.), itwill induceauniquesetofmodesofaction. Accordingly, onewould – in theory – need to perform amultiple stressor assess- mentof each singleparticle,which is in itself a complexmixture.Fromapractical perspective, the integration from multiple stressors in risk assessment is challenging – traditionally each stressor is considered individually. For instance, existing regulations refer to the total concentrationof suspendedparticulatematter (SPM) or for single pollutants adsorbed to SPM.Currently, chemical and particu- late parameters are not integrated – aswouldbe required forMP regulation. Hence, an alternative approach to categorizeMP for regulation might by the fieldof application or by the source for environmental entry. Plastics are used in a wide rangeof applications includingpackaging, constructionmaterials, cosmetics, electrical and evenmedical devices, etc. Obviously, distinct regulatorymeasures are required to manage the proper recycling of electronic devices compared to throwaway packagingmaterials or to reduceMP in cosmetics – even though the same polymers might be used in these completely different products. In conse- quence of their broad use, (micro)plastics enter ecosystems via various pathways. Hence, regulatory measures must not necessarily refer to groups based on MP properties but can also act on groups of sources or entry pathways such aswaste- water, incorrect disposal, or agricultural runoff. As we have seen above, we have different options of grouping MPs. The microbead ban, to name just one example frompractice, clearly categorizesMPs bythefieldofapplication(cosmetics/personalcareproducts).Whichcharacteristics one select for categorizationdependson the regulatory context. Environmental policyhasdevelopeda long list ofgeneral and specificmanage- ment options applicable to a variety of environmental issues (including waste management and water resource management). Some of these might be adopted for the regulationofMPs. 3.4 GeneralRegulationOptions byEnvironmentalPolicy: Applicable forMP? Environmental policyaimingat protectingecosystemsand improving theenviron- mental statuscanbe implementedbyvarious regulatory instruments andmeasures. An intervention can take place on different statutory levels – ranging fromvolun- tary commitments to legally binding bans of certain materials. Furthermore, the interventions can differ regarding the implementation level – including direct regulation of production and application ofmaterials, improvement of waste and watermanagement,and long-termmeasuresaimingat socialawarenessandchang- ing of behavior. Exhaustive compilations regarding environmental policy instru- ments are given, e.g., by theOECD [67, 68]. Some of those generally applicable FreshwaterMicroplastics:Challenges forRegulation andManagement 259