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%被用于垃圾填埋或自然环境。因此，塑料垃圾随处可见，而且持续存在。塑料一暴露在阳光下，就会慢慢降解成被称为微塑料的微小颗粒和纤维。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。如果小到可以吸入，空气中的微塑料可以进入呼吸道。从这里，它们可能被粘液清除到肠道，或者它们可能进入肺深部，在那里它们与肺液和细胞相互作用。由于塑料不能分解，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，有几种方法可以预测微塑料会造成伤害。它们可能会引发炎症反应，因为它们类似于免疫细胞试图清除的异物。它们还可能携带一种化学物质的鸡尾酒。这些包括在塑料产品制造过程中加入的添加剂，以及来自周围环境的集中在其表面的化学物质。众所周知，这类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。鉴于人体暴露的风险，迫切需要评估微塑料对健康的潜在影响。然而，缺乏关于人群暴露的确凿证据基础--包括微塑料浓度、类型和大小。该奖学金旨在通过评估微塑料是否可吸入空气；人类是否通过空气接触微塑料；以及暴露是否会导致健康影响来解决这一问题。这项研究将在医学研究理事会(MRC)-英国公共卫生环境与健康中心(伦敦国王学院)与MRC毒理学小组(莱斯特)合作进行。测量空气质量的仪器将被用于收集空气中的颗粒物。样品将用显微镜进行评估，显微镜连接到能够检测独特化学特征的仪器，称为拉曼光谱，以检测微塑料。将对微塑料进行计数、确定大小并确定塑料的类型。为了评估人类是否接触到微塑料，将对在医疗过程中常规收集的人类肺组织样本进行筛查。样品将在与拉曼光谱仪耦合的显微镜下观察，可疑颗粒的特征如上所述。为了了解微塑料造成危害的可能性，将在动物模型中筛选微塑料的不同特征--如塑料类型、大小、形状和表面化学。拟议项目的成果是：1)有一种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宜性；3)全面提高对微塑料对人类健康风险的认识。将微塑料按塑料类型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.