Removing unwanted macro, micro and nanoplastics from fresh produce production

从新鲜农产品生产中去除不需要的宏观、微观和纳米塑料

• 批准号: 2440349
• 金额: --
• 依托单位: University of Surrey
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2440349
• 关键词: Removing; unwanted; macro; micro; nanoplastics

Global plastics production in 2019 was 359 million tonnes. Of the 62 million tonnes produced in Europe, only 9.2 million tonnes was collected for recycling, leaving the remainder to be disposed of on land or in marine environments, to the detriment of those ecosystems. Recent work has demonstrated that macro plastics, e.g. plastic bags, break down over time into micro- or nano-plastic particles. These microscopic plastics have been investigated in the marine environment and it has been found that marine wildlife, such as scallops and mussels ingest these, and they become distributed throughout the body of the organism. However, to date, no work has been done on terrestrial environments to find out whether nano-plastics can be taken up by plant roots and potentially enter the human food chain. Since plant roots are designed to absorb nutrients and small molecules from the soil it seems likely that this could occur. This project will characterize the abundance and distribution of macro, micro and nano plastics in a crop cultivation environment using Scanning Electron Microscopy. The project will use 14C radiolabelled spherical nanopolymers in a hydroponic experimental set up that will investigate whether plants can take up these particles and find out where in the plant they are subsequently distributed, using liquid scintillation counting and phosphorimaging. We have chosen to focus on the leafy salad industry as the environment in which to investigate plastic contamination, since businesses depend heavily on it to preserve the quality of the crops they grow. Much of the European supply of vegetables and fruit is produced in a region of southern Spain called Almeria, where 2,700,000 metric tons per year of produce is harvested over a region covering 30,000 hectares, nearly all of which is covered in plastic. Standard practice in Almeria is to cover the crops in plastic tunnels or plastic mulch which is then ploughed into the soil when the crop is harvested. The mulch is used to keep the soil temperature warm enough for plant growth, to prevent evaporative water loss, to suppress weed growth instead of using herbicide, and to reduce soil erosion. Nanoplastics (<1000nm) are expected to be generated by repeated cultivation of land containing waste plastic mulching material. Leafy salads also use plastics throughout the supply chain, in order to maintain freshness of the crop, to prevent microbial contamination, and to extend shelflife. Almeria produces the major proportion of conventionally and organically grown salads consumed in the UK between September and March. Disposable plastics are used throughout the supply chain for crate liners, wrapping pallets and product packaging. In the case of crate liners and pallet wrappers, waste management streams are well controlled, enabling most UK fresh produce businesses to claim zero waste to landfill. However, packaging used for bagged baby and cut salad leaves does not have a good waste management stream and companies are starting to explore alternatives including biodegradable and compostable packaging. Although these concepts are good, research has indicated that degradation of these materials is often poor. More work is required to develop bio-based packaging materials that are truly biodegradable. The project will evaluate the potential for bio-based packaging to preserve leafy salad quality and shelf life, alongside assessing the ability of these types of packaging to degrade in different environments that reflect possible disposal routes.The project will evaluate the sustainability of different production and supply chain practices in relation to plastic use and ensure that alternative materials to hydrocarbon polymers represent a real improvement in sustainability.

2019年全球塑料产量为3.59亿吨。在欧洲生产的6200万吨中，只有920万吨被收集用于回收，其余的则被丢弃在陆地或海洋环境中，损害了这些生态系统。最近的研究表明，宏观塑料，如塑料袋，随着时间的推移会分解成微或纳米塑料颗粒。这些微小的塑料在海洋环境中被研究发现，海洋野生动物，比如扇贝和贻贝，会摄入这些塑料，它们会分布在生物体的全身。然而，到目前为止，还没有在陆地环境中进行研究，以确定纳米塑料是否可以被植物根部吸收并可能进入人类食物链。因为植物的根是用来从土壤中吸收养分和小分子的，所以这种情况很可能发生。本项目将利用扫描电子显微镜对作物栽培环境中宏观、微观和纳米塑料的丰度和分布进行表征。该项目将在水培实验装置中使用14C放射性标记的球形纳米聚合物，利用液体闪烁计数和磷成像技术，研究植物是否能吸收这些颗粒，并找出它们随后在植物中的分布位置。我们选择把重点放在绿叶沙拉行业，作为调查塑料污染的环境，因为企业在很大程度上依赖于它来保持他们种植的作物的质量。欧洲供应的大部分蔬菜和水果都产自西班牙南部一个名为阿尔梅里亚（Almeria）的地区，在那里占地3万公顷的土地上，每年收获270万吨农产品，几乎所有土地都被塑料覆盖。阿尔梅里亚的标准做法是用塑料隧道或塑料覆盖物覆盖作物，然后在作物收获时将其犁入土壤。地膜用于保持土壤温度足够温暖，以供植物生长，防止蒸发水分流失，抑制杂草生长而不是使用除草剂，并减少土壤侵蚀。纳米塑料（<1000nm）有望通过含有废塑料覆盖材料的土地的重复耕作而产生。绿叶沙拉在整个供应链中也使用塑料，以保持作物的新鲜度，防止微生物污染，并延长保质期。在9月到3月期间，阿尔梅里亚生产了英国消费的大部分传统和有机沙拉。一次性塑料在整个供应链中用于板条箱衬垫，包装托盘和产品包装。在板条箱衬垫和托盘包装的情况下，废物管理流得到很好的控制，使大多数英国新鲜农产品企业声称零废物填埋。然而，用于袋装婴儿和切好的沙拉叶的包装没有良好的废物管理流，公司开始探索包括可生物降解和可堆肥包装在内的替代品。虽然这些概念很好，但研究表明，这些材料的降解能力往往很差。开发真正可生物降解的生物基包装材料还需要做更多的工作。该项目将评估生物基包装在保持绿叶沙拉质量和保质期方面的潜力，同时评估这些类型的包装在不同环境下的降解能力，这些环境反映了可能的处理途径。该项目将评估与塑料使用相关的不同生产和供应链实践的可持续性，并确保碳氢化合物聚合物的替代材料在可持续性方面取得真正的进步。