Microplastic entrainment, transport and fragmentation in atmospheric boundary-layer flows

大气边界层流中的微塑料夹带、传输和破碎

基本信息

批准号：
NE/X00015X/1
负责人：
Joanna Bullard
金额：
$ 70.8万
依托单位：
Loughborough University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2023
资助国家：
英国
起止时间：
2023 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FX00015X%2F1
关键词：
Microplastic entrainment transport fragmentation atmospheric

项目摘要

Plastics are central to modern living, supporting innovations in manufacturing, health care and construction. However, they are also recognised as an emerging and 'poorly reversible' pollutant which may have serious consequences for human health via pollution, ingestion and inhalation as well as global biogeochemical cycling and ecosystems functioning. A great deal of attention and publicity has been given to environmental issues associated with macroplastics such as plastic bottles, bags, balloons and packaging, particularly with regards to oceans and marine wildlife. However, all plastic originates on land and during the journey from land to ocean macroplastics can breakdown in to smaller microplastics through impact, tearing and disintegration or 'aging' due to solar radiation. Microplastics may also be deliberately produced for various manufacturing processes. Microplastics, which are defined as those smaller than 5 mm across, are light in weight and can not only be transported by water but also by wind. They are incorporated into soils via agricultural treatments (e.g. application of sewage) or when rivers carrying them flood. When the soils dry out, the wind can pick up the microplastics along with mineral particles and transport them long distances.There has been very little research into airborne microplastics and most of this has concentrated on the deposition, or 'fall out' of particles. In contrast, this proposed research focuses on the processes by which the wind picks up the microplastic particles and whether the movement of microplastics by wind can cause their material properties (such as size, shape, elasticity) to change. For example, if microplastics are mixed in with soil particles their presence may change the relative importance of different processes that occur during wind erosion as particles interact with each other. Microplastics will have different shapes and densities compared to mineral particles and may cause an increase or decrease in the wind speed needed to trigger wind erosion. When microplastics are picked up by the wind they will collide with other microplastics but also with mineral particles and the ground surface. These collisions may change the surface properties of the microplastics making them rougher or causing the development of cracks, and could also cause the microplastics to break or fragment into smaller particles. Rough particles are more likely to carry pollutants and smaller particles are more likely to be transported long distances and could also be inhaled by people and animals.We will examine the processes by which microplastics are entrained by the wind and how they interact with other particles (plastic and mineral) in the air using wind tunnel experiments. To understand how the properties of microplastics change during wind transport we will use abrasion chambers that simulate the action of the wind on particles. Our experimental approach makes it possible to control variables such as wind speed, sediment type, microplastic type and the concentration of microplastics in the soil. We can also examine the effect of air temperature to see whether microplastics behave differently when the air is cold (such as in the Arctic and we expect the plastic to be more brittle) or warm (such as in the tropics where plastics are expected to be more elastic). The research has wider implications beyond that of microplastic transport. Very little is known about how mixtures of low and high density small particles behave during wind erosion. Although we will focus the behaviour of low density microplastics, other low density materials that can be found in soils (naturally or through pollution) include organic matter, biochar, ash and natural textile fibres such as wool or cotton and our results will also be relevant to understanding their dynamics in response to wind erosion.

塑料是现代生活的核心，支持制造，医疗保健和建设方面的创新。但是，它们也被认为是一种新兴且“不利的”污染物，它可能通过污染，摄入和吸入以及全球生物地球化学循环和生态系统的功能对人类健康产生严重影响。对与大型塑料相关的环境问题（例如塑料瓶，袋子，气球和包装，尤其是关于海洋和海洋野生动植物的疑问），已经引起了很多关注和宣传。但是，所有塑料均起源于陆地和从陆地到海洋大型塑料的旅程，可以通过撞击，撕裂和瓦解和瓦解或由于太阳辐射而崩溃或“衰老”，从而破坏了较小的微塑料。微塑料也可以故意用于各种制造工艺。微塑料定义为小于5毫米的微型塑料，重量轻，不仅可以通过水运输，而且可以通过风转运。它们通过农业处理（例如污水的施用）或河流泛滥的河流将其纳入土壤中。当土壤干燥时，风可以与矿物颗粒一起捡起微塑料并将其运输长距离。对空气中的微塑料的研究很少，其中大部分集中在沉积上，或“掉落”颗粒。相比之下，这项提出的研究重点是风拾取微塑料颗粒的过程，以及微塑料乘风的运动是否会导致其材料特性（例如大小，形状，弹性）改变。例如，如果将微塑料与土壤颗粒混合在一起，它们的存在可能会改变随着颗粒相互作用时风侵蚀期间发生的不同过程的相对重要性。与矿物颗粒相比，微塑料的形状和密度不同，可能会导致触发风侵蚀所需的风速增加或降低。当微型塑料被风捡起时，它们将与其他微塑料相撞，还会与矿物颗粒和地面相撞。这些碰撞可能会改变微塑料的表面特性，从而使它们变得更粗糙或引起裂纹的发展，也可能导致微塑料破裂或碎片成较小的颗粒。粗糙的颗粒更可能携带污染物，较小的颗粒更有可能长距离运输，并且也可能被人和动物吸入。我们将检查风风孔以及它们如何与其他颗粒（塑料和矿物）在空中使用风隧道实验相互作用的过程。为了了解微塑料在风转运过程中的特性如何变化，我们将使用模拟风对颗粒的作用的磨损室。我们的实验方法使控制变量，例如风速，沉积物类型，微型塑料类型和土壤中微塑料的浓度。我们还可以检查空气温度的效果，以查看当空气冷（例如在北极中，我们期望塑料会更脆）时（例如，预计塑料会更弹性的热带地区）时，微塑料的行为是否有所不同）。这项研究具有超出微塑料运输的含义。关于小颗粒在风侵蚀期间的低密度和高密度混合物的表现知之甚少。尽管我们将集中于低密度微塑料的行为，但是在土壤中可以发现的其他低密度材料（自然或通过污染）包括有机物，生物炭，灰烬和羊毛纤维（例如羊毛或棉花），我们的结果也将与对风侵蚀的响应中的动态有关。