Page - 255 - in Freshwater Microplastics - Emerging Environmental Contaminants?

microbead is defined as “any solid plastic particle that is less thanfivemillimeters insizeand is intended tobeused toexfoliateorcleanse thehumanbodyoranypart thereof” (including toothpaste) [49, p. 1]. In this act, the term “microbead” is precisely defined. It refers to primary microplastics and thus provides a direct regulation instrument to tackle the problems relatedwith it, e.g., the pollution of freshwater systems. 3 Challenges ofCurrentRegulation:Reasons andRequirements forFutureManagement As shown above, policy-makers are very aware of the problems of environmental plastic waste, and these issues are already considered in several regulatory docu- ments.Nevertheless,most regulations donot clearly refer tomicroplastics. There- fore, this section aims to highlight the open questions and identify the challenges and the requirements for the future management ofMP from the perspective of scientific authorities. 3.1 DoWeNeedRegulationofMicroplastics atAll? Somecriticsdebate theneedforaregulationofMPandquestionwhether it isonlya “media-made” problem. Indeed, the general public’s concern is driven by sensa- tionalized media reports about enormous numbers of MP in the environment. However, there is little scientific data on adverse effects caused by relevant envi- ronmentalconcentrationsofMP.Usually,effectsweredetectedinlaboratorystudies that have tested concentrations far abovemeasured environmental concentrations (see [50] for effects ofMP toorganisms). So far, onlyone study reports significant impacts ofMPonfish larvae at concentrations found in coastalwaters [51].4 Nevertheless, MPs occur in almost all types of freshwater environments – ranging fromstreams in densely populated areas to lakes in almost non-populated areas, e.g., inMongolia ([52–55], [19, 56, 57]; see [58, 59] for further discussion). Additionally,MPspersist over centuries under commonenvironmental conditions [60].Thus, in the special caseof suchextremelypersistent pollutants suchasMPs, themotivation for any regulatory efforts shouldnot bebased solelyon thedemon- strationofadverseeffectsatcurrentenvironmentalconcentrations. IfMPinput into the environment continues at the current level, environmental concentrationswill increase dramatically. Ubiquitous detection, persistency, and continuing release shouldmotivate policy-makers and regulators to act immediately according to the precautionary principle to stop a further plastic accumulation. 4Note fromtheeditors:Thecitedpublicationhasbeen retractedbecauseof scientificmisconduct. FreshwaterMicroplastics:Challenges forRegulation andManagement 255