Atmospheric microplastics, their accumulation in vivo and potential toxicity.

自20世纪50年代开始大规模生产以来，已经生产了超过80亿吨塑料。其中80%被填埋或自然环境。因此，塑料垃圾很普遍，而且仍然存在。在暴露于阳光下时，塑料会慢慢降解成微观颗粒和纤维，称为微塑料。微塑料也是有目的地制造的，例如用于个人护理产品的微珠。在食物和我们呼吸的空气中发现了微塑料，这引发了人们对公共健康风险的猜测。如果小到足以被吸入，空气中的微塑料可能会进入气道。从这里，它们可能被粘液清除到肠道，或者它们可能进入肺部深处，在那里它们与肺液和细胞相互作用。由于塑料不能被分解，微塑料有可能通过嵌入组织或进入细胞而留在我们的体内。暴露后，预计微塑料会以几种方式造成伤害。它们可能会引发炎症反应，因为它们类似于免疫细胞试图消除的异物。它们还可能携带化学物质的混合物。这些包括在塑料产品制造过程中加入的添加剂，以及周围环境中集中在其表面的化学品。已知这些化学物质会导致基因突变、癌症和生殖影响。此外，微塑料携带一种新的微生物群落，包括有害类型。鉴于人类接触的风险，迫切需要评估微塑料的潜在健康影响。然而，缺乏关于人群暴露的坚实证据基础-包括微塑料浓度，类型和大小。该研究金旨在通过评估可吸入尺寸的微塑料是否通过空气传播来解决这一问题;人类是否通过空气暴露于微塑料;以及暴露是否会导致健康影响。该研究将在医学研究理事会（MRC）-英格兰环境与健康公共卫生中心（伦敦国王学院）与MRC毒理学部门（莱斯特）合作进行。测量空气质量的仪器将用于收集空气中的颗粒。将使用显微镜对样品进行评估，显微镜与能够检测独特化学特征的仪器（称为拉曼光谱）耦合，以检测微塑料。微塑料将被计数，大小和塑料的类型确定。为了评估人类是否暴露于微塑料，将筛选在医疗程序中收集的人类肺组织样本。将在耦合到拉曼光谱仪的显微镜下观察样品，并如上所述表征可疑颗粒。为了了解微塑料造成伤害的可能性，将在动物模型中筛选微塑料的不同特征，例如塑料类型，大小，形状和表面化学。拟议项目的成果是：（1）有一个标准方法来监测不同环境（如城市、沿海和农村）空气中的微塑料;（2）确定组织作为暴露指标的适用性;（3）全面提高对微塑料对人类健康风险的认识。按塑料类型对微塑料进行分类将突出那些需要通过资源和废物管理以及材料和产品设计来改进监管的塑料。

Over 8 billion tonnes of plastic have been made since mass production began in the 1950s. Eighty per cent of this has gone to landfill or the natural environment. Consequently, plastic litter is widespread and it persists. Upon exposure to sunlight, plastic slowly degrades into microscopic particles and fibres known as microplastics. Microplastics are also purposefully manufactured, such as microbeads used in personal care products. Microplastics have been found in food and the air we breathe, prompting speculation about risks to public health. If small enough to be inhaled, airborne microplastics could enter the airway. From here they may be cleared with mucus to the gut, or they may enter the deep lung where they interact with lung fluid and cells. As plastic cannot be broken down, microplastics have the potential to persist in our bodies by embedding in tissues or entering cells. Following exposure, there are several ways in which microplastics are predicted to cause harm. They may trigger an inflammatory response, as they resemble foreign bodies which immune cells try to eliminate. They may also carry a cocktail of chemicals. These include additives that are incorporated during plastic product manufacture, and chemicals concentrated on their surface from the surrounding environment. Such chemicals are known to cause genetic mutations, cancer and reproductive effects. Additionally, microplastics carry a novel community of microbes, including harmful types. Given the risk of human exposure, there is an urgent need to assess the potential health impacts of microplastics. However, a solid evidence base for population exposure - including microplastic concentrations, types and sizes - is lacking. This fellowship aims to address this by assessing whether microplastics down to an inhalable size are airborne; if humans are exposed to microplastics via the air; and whether exposure could lead to health effects. The research will be conducted at the Medical Research Council (MRC)-Public Health England Centre for Environment and Health (King's College London) in partnership with the MRC Toxicology Unit (Leicester). Instruments which measure air quality will be used to collect airborne particles. Samples will be assessed with a microscope coupled to an instrument capable of detecting unique chemical signatures, known as Raman spectroscopy, to detect microplastics. Microplastics will be counted, sized, and the type of plastic identified. To assess whether humans are exposed to microplastics, human lung tissue samples routinely-collected during medical procedures will be screened. Samples will be viewed under a microscope coupled to a Raman spectrometer and suspicious particles characterized as above. To understand the potential for microplastics to cause harm, varying characteristics of microplastics - such as plastic type, size, shape and surface chemistry - will be screened in a an animal model. The outcomes of the proposed project are to 1) have a standard method to carry out monitoring of microplastics in the air in different environments (such as urban, coastal and rural); 2) to determine the suitability of tissue as an indicator of exposure; and 3) have an overall increased understanding of the risk that microplastics present to human health. Classifying microplastics by plastic type will highlight those plastics which require improved regulation via resource and waste management, and material and product design.