Purpose and Necessity of Nanoparticle Regulation

Transcription

1 I. Introduction Purpose and Necessity of Nanoparticle Regulation A rapidly emerging new field of study is nanotechnology and its real-life applications. Nanotechnology involves the study and application of nanoscale materials (between 1 and 100 nanometers) in fields ranging from materials sciences to pharmaceuticals. Nanoparticles are used in everyday items, ranging from cosmetics such as sunscreen and eyeshadow to clothing. Various controversies have emerged regarding nanoparticles, such as its chemical definition, the extent to which it should be regulated, its effects on the environment, and whether it s safe for consumers. Despite nanotechnology s ability to have life-changing applications, regulation on nanoparticles has been lax and incomplete. Instead of creating national and international regulatory frameworks, industries and international organizations have shied away from the behemoth task and instead adhered to existing chemical regulation guidelines that are insufficient for regulating nanoparticles. This article aims to raise awareness about the importance of nanoparticle regulation, review current legislation, propose policy solutions, and cite past examples of where the failure to regulate emerging biotechnologies has led to severe impacts on the environment and human health. II. Resolving the Definition Debate a. Definition of Nanoparticle One major controversy within nanoparticle regulation is the definition of what a nanoparticle is. It is widely agreed that nano is anything from 1 to 100 nanometers (Lovestam et al.), yet this is where the divergence occurs: there is a disagreement on whether agglomeration or aggregation of nanoparticles should be considered. Aggregation and agglomeration are often used interchangeably, yet these two terms are inherently different, which only led to more confusion in nanoparticle regulation (Nichols et al. 2104). The ISO Technical Specification defines agglomeration as collection of weakly-bound particles or mixtures of the two where the resulting external surface area is similar to the sum of the surface areas of the individual components (Linsinger, Roebben, and Gilliland 13). Essentially, agglomerates are not fixed units and can be changed by various conditions such as temperature, ph, and pressure (Walter 10), meaning that the physical properties of agglomerates can be changed by its environment and chemical composition. Agglomerates can either break down into smaller agglomerates or condense into larger ones. In contrast, aggregation is particle[s] comprising stronglybonded or fused particles where the resulting external surface area may be significantly smaller than the sum of the calculated surface areas of the individual components (Linsinger, Roebben, and Gilliland 13). Even though the definitions provided by the ISO are widely accepted, the definitions are often used interchangeably, and many industries often have their own definitions, which adds confusion to nanoparticle regulation in addressing whether nanoparticles include agglomeration, aggregation, or both (Nichols et al. 2104). b. Definition of Chemical substance A key issue that needs to be resolved is what constitutes as a chemical substance. There is no specific legislation that regulates nanoparticles, but rather, even though nanoparticles behave differently, nanoparticles are regulated by existing legislation under the umbrella term chemical substance. Defining chemical substance is imperative to ensuring that there is uniform international nanoparticle regulation. For instance, the Environmental Protection Agency (EPA) defines a chemical substance based on molecular identity (Lebedev 23). This means that nanoparticles used in consumer products, such as titanium dioxide (TiO 2) in sunscreen are declared as safe, since despite clear functional differences

2 between bulk-sized and nanoscale TiO 2 molecules, its bulk form (which contains the same molecular identity as the nanoscale form) was previously approved (Lin 374). The TiO 2 molecules in its bulk form has a significantly greater physical size compared to its nanosized form, making its physical and chemical properties different. Some legislation, such as the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH 2006) and the Classification, Labelling and Packaging Regulation (CLP 2008) legislation of the European Chemicals Agency (ECHA) defines chemical substance as not just based on molecular identity, but including all physical states, crystal structures, and dimensions of a substance (Alessandrelli and Polci 148). However, by 2007, ECHA still treated bulk material and nano-sized material as the same substance (Alessandrelli and Polci 148). c. Dangers of Nanoparticles Treating nano-sized and bulk-sized materials as the same is dangerous. Even though nanoparticles such as TiO2 are often used in food preservatives and may not be toxic, numerous studies have shown that their nanoscale size make them hazardous. Experiments on daphnia (commonly known as waterfleas) have shown that nano-sized TiO 2 causes severe growth retardation, mortality, and reproductive defects. Some studies demonstrate that when inhaled, nano-sized TiO 2 can damage the pulmonary wall and cause pulmonary tumors (Ostiguy and Cloutier). In addition, TiO 2 particles may be toxic to the environment. TiO 2 nanoparticles, through oxidative stress, damage the cell membranes of Bacillus licheniformis, a type of common soil bacterium (Maurer-Jones et al.). Other types of nanoparticles, such as copper and zinc nanoparticles, can cause DNA damage in plants and terminate root elongation, which is necessary for plant survival (Lin and Xing). Thus, standards must be better defined so the safety of nanoparticles can be determined, measured, and regulated when necessary. III. Nanoparticle Testing Standards Even if the definitional debate of nanoparticle can be resolved, standards for testing procedures and timelines still pose problems for policymakers. In the United States, the Environmental Protection Agency (EPA) controls most substances emitted into the environment under the Toxic Substances Control Act (TSCA). As the TSCA defines chemical substance based on molecular identity, nanoparticles are no longer new substances, so it is not required for manufacturers to notify the EPA prior to manufacture (Lebedev 24). The definition of chemical substance in the TSCA is: "any organic or inorganic substance of a particular molecular identity, including -- (i) any combination of such substances occurring in whole or in part as a result of a chemical reaction or occurring in nature and (ii) any element or uncombined radical" (PC). The EPA can require notice under the significant new use clause (Lebedev 25); however, even if nanoparticles are created with significantly new properties and used for significantly new purposes, they are still regulated as existing substances, making regulation extremely difficult. Furthermore, the main issue with the TSCA is that it creates an exemption for any food, food additive, drug, cosmetic, or device (Lebedev 25). This essentially cordons off nanoparticles outside of EPA control, as most nanoparticles are used in cosmetic products and drugs. In order to successfully control a chemical substance, the EPA needs to prove that the substance may present an unreasonable risk or injury to health or the environment (Lebedev 25). This is a heavy burden on the EPA, as before testing can even be conducted, the EPA has to also prove that the possibility of risk is more than theoretical (Lebedev 25). Limited data on the toxicity of nanoparticles and lack of knowledge on nanoparticle toxicity testing methods makes this extremely difficult (Lebedev 25), severely hindering the EPA s regulatory power. This introduces another significant issue in nanoparticle regulation, which is the lack of standardized testing methods. Nanoparticles cannot be tested under traditional chemical substance risk assessments, as the risks

3 of chemical substances are assessed based on their chemical identity, which ignores the specific characteristics of nano-sized particles. Present nanoparticle testing follows a case-by-case scenario, where substances will only be tested when a case arises, as there is no hazard identification system in place (Commission). This means that dangers regarding nanoparticle products are only addressed when the threat arises, and threats are often not recognized until it has caused irreversible harm. Each specific property of nanoparticles needs to be taken into consideration and every alteration in nanoparticle property (such as physical, optical, and chemical properties) will affect the overall hazard level, making a hazard identification system extremely difficult to create (Europe). Additionally, nanoparticles can break down, condense, or have its chemical and physical properties altered due to how the product is handled over its life cycle. Seeing as there are hazard identification systems for other chemical substances, it is logical that with its increasing consumer applications, one is created for nanoparticles as well. Besides this, as nanoparticles are implemented in everyday products, their properties change over their life cycle, making its toxicity at different stages during their shelf life different (Europe). So far, little attention has been given to how toxicity of nanoparticles in consumer products change over time (Europe), making nanoparticle testing extremely difficult and expensive for regulatory agencies, further hindering their ability to successfully govern industries. IV. Past Failure to Regulate New Substances: Lessons from Microplastics There are multiple cases of where past failures to regulate new chemical substances led to irreversible damage, with the most notable example being microplastics. Microplastic is generally defined as plastic particles with a diameter up to 5mm, and just like nanoparticles, an internationally agreed definition does not exist (Girard et al. 6). A clear and universally agreed upon definition is necessary for enforcement and regulation. Microplastics are usually in the form of microbeads, which are small pieces of manufactured polyethylene plastic often used in cosmetic products such as exfoliants and toothpaste (Commerce). Canada defines microbeads in the Canadian Environmental Protection Act as synthetic polymers that, at the time of their manufacture, are greater than 0.1 μm and less than or equal to 5 mm in size. However, the definition was then narrowed to a diameter between 0.5µm and 2mm (Girard et al. 7). The United States does not provide a lower limit but defines it as having an upper limit of up to 5mm (Girard et al. 7). The definitional debate, which is highly reminiscent of the definitional debate over nanoparticles, is where the first issue occurs: essentially, microplastics over 2mm or under 0.5µm in diameter are still allowed (Girard et al. 7). This encompasses nanoplastics, which harm the environment due to its high similarity with microplastics (Girard et al. 7). In 2015, the United States passed the Microbead-Free Waters Act of 2015, which defines microbeads as any solid plastic that is less than 5 mm in length (Girard et al. 18), which does not take in account biodegradability and hence resolves potential loopholes. Despite recent collective international efforts to regulate microbeads, undoubtedly, the damage has already done. The dangers of plastic litter as a pollutant to the environment was recognized almost twenty years ago, has received widespread attention and is the subject of various regulations (Gorycka 2). However, microplastic pollution was not recognized until after the 1970s, and the first conference to bring awareness to the dangers of microplastic did not occur until the International Research Workshop on the Occurrence, Effects, and Fate of Microplastic Marine Debris in 2008 (Gorycka). It is estimated that the volume of microplastic litter has tripled in the North Pacific as of 2005 during the last decade, and the amount of microplastic debris in the waters off Japan increases 10 times for every 2 to 3 years (Gorycka). Mass accumulation of plastic litter has shown to damage the marine food chain and cause deaths of aquatic animals (Gorycka). Additionally, due to its size, microplastics are not sifted out during the wastewater treatment process, making it being released into bodies of water, causing irreversible harm (Hellmann). This is the reason for why Illinois became the first state to ban microplastics in cosmetic products in 2014 (Hellmann).

4 Even though substantive research has been conducted on the accumulation of plastics in marine creatures, specific research about the effect of microplastics in animals is a newer area of research (Steensgaard et al. 290). Since microplastics are roughly the same size as plankton, the possibility of it being ingested by greater number and variety of aquatic animals increases significantly, with ingestion causing blockage in the digestive tract and harm caused to the organism by absorbing chemicals from the microplastic (Gorycka). In addition, microplastics with different properties lead to different consequences; for instance, plastics with a high density, such as polyvinyl chloride (which is one of the most common compositions of microbeads), can accumulate easily in sediments, which increases ingestion by filter feeders such as clams and sponges (Smithsonian Museum of Natural History; The Government of Canada; Gorycka). Regarding humans, ingestion of microparticles can enter the circulatory system through the gut, yet more research needs to be done on the exact risks caused (Galloway 351). This lesson from the failure to recognize the dangers of microplastics and regulate it efficiently should serve as a warning sign to the importance of regulating nanoparticle usage. V. Recent Efforts in Nanoparticle Regulation There has been increasing international efforts to resolve challenges facing nanoparticle regulation. More resources have been dedicated to the research and development of nanoparticles. For instance, the European Commission Directorate-General for Research and Innovation has enacted the European Union (EU) Nanosafety Cluster, which are working groups dedicated to analyzing nanoparticle risks, model nanoparticle release, research existing nanoparticle regulations, and establish standard testing and data management systems (Cluster). The working groups are not yet coming up with standards to measure nanoparticle risk, but are rather carrying out risk profiles of products with nanoparticles with industry partners and then moving on from that point towards more research. Most notably, the various working groups are grouping the various definition for nanoparticle in existing international regulatory frameworks based on characteristic, networking with industries to implement Safe by Design (SbD) methods, and devising a model that estimates how an engineered nanomaterial is released along a product chain (Cluster)Despite the efforts and the strides taken in nanoparticle research, however, no legislation unique to regulating nanoparticles has been proposed. VI. Policy Proposals The first step is to resolve the conflict over agglomeration and aggregation, and both situations should not affect how nanoparticle is defined. Instead, the physical properties of nanoparticles should be defined at when it was manufactured and not during the remaining stages of its life cycle. For instance, when a cookie is sold, its price and type is determined based on its ingredients and size. The type and size of a cookie should not be defined when it is eaten halfway or when it becomes cookie crumbs, but rather should be defined as by the ingredients labelled by the manufacturers when produced. This is the same scenario for nanoparticles, where unlike cookie crumbs, the nano-scale does make a difference in function. In order to pass any effective policy, a standard definition for nanoparticle must be established. Nanoparticles must be regulated, under existing chemical legislation, as new substances. A proposed universal definition for a nanomaterial is: Any particle, substance, or material between 0 and 100 nanometers when measured before releasing to consumers. Aggregation and agglomeration are not taken into account. The term material is then defined as a single or closely bound ensemble of substances at least one of which is in a condensed phase, where the constituents of substances are atoms and molecules (Lovestam et al. 22). This covers inorganic, organic, and manufactured nanomaterials such as liposomes, nano-emulsions, micelles, and other forms of nanocarriers applied in the cosmetic and food sectors (Lovestam et al. 22). The term substance is defined by REACH as a chemical element and its compounds in the natural state or obtained by any manufacturing process, including any additive necessary to preserve its stability and any impurity deriving from the process used, but excluding any solvent which may be sepa- rated without affecting the stability of the substance or changing its composition (Lovestam et al. 10). As substance is already

5 defined clearly in REACH, the utilization of REACH s definition of substance in defining engineered nanomaterial allows nanoparticles to be regulated under REACH as well when separate legislation for regulating nanoparticles is still being revised. The next step is then to provide a universal definition for chemical substance. The definition of chemical substance must be altered to define substances based on both physical properties and chemical identity instead of only molecular identity to allow a distinction between nanoscale substances and its parent bulk size substance. A proposed definition is: a chemical substance is: any substance of a specific combination of physical and chemical identity that exhibit a certain behavior. Although it may take time for legislational changes to be made, regulations should be made regarding manufactures. Manufacturers should follow the aforementioned ProSafe (Promotion of Safe by Design) implementation concept created by the European Union that integrates innovations, regulatory affairs, and data handling. ProSafe includes the development of a Safety Dossier (Appendix B) and Safety Profile (Hohener, Hock, and Lehmann). The Safety Dossier contains a flowchart for risk assessment, with stages ranging from hazard assessment to corporate and social responsibility (Hohener, Hock, and Lehmann). As a part of the EU NANoREG project, ProSafe provides a value chain as a basis for arranging innovation and R&D projects (Hohener, Hock, and Lehmann). Manufacturers should align research according to NANoREG s SbD concept, ProSafe Safety Dossier and Safety Profile. An image of the illustration of the value chain is shown in Appendix A. Within SbD, there is a harmonized inventory with databases, characterization, detection of nanomaterials in complex biologic and environmental samples, grouping, exposure and the life cycle, and knowledge-sharing methods(hohener, Hock, and Lehmann). Governments should require manufacturers to follow the SbD implementation methods as closely as possible to ensure that the environmental and health risks of nanoparticles can be minimized as much as possible. Regardign R&D, it should be enforced that any company that utilizes nanoparticles in its products much participate with organizations such as the EU NanoSafety Cluster project as industry partners to help progress research in risk assessments of nanoparticles. With more power comes more responsibility, and manufacturers need to take on some burdens for the materials they use. In addition, laws need to require manufacturers to explicitly label products that contain nanoparticles so that consumers can be aware of what they are using. Lastly, the burdens of regulatory agencies must be decreased. When new nanomaterials are manufactured, testing should be made mandatory regardless of whether there s a potential for risk. Although this may lengthen the approval process and increase administrative costs, companies should split burdens with regulatory bodies and be required to pay half of the testing costs. In addition, if regulatory bodies such as the EPA cannot handle testing, testing should be partly financed by a tax on nanotechnology products or be turned over to neutral third parties.

6 Appendix A: Overview of the NANoREG SbD concept and ProSafe Safety Dossier and Safety Profile

7 Appendix B: Structure of ProSafe Safety Dossier