In situ, radio frequency detection and analysis of microplastics in environmental water

Microplastics (MPs), ranging from 1 µm to 5 mm, have become ubiquitous environmental pollutants, food contaminants, and health threats. It was suggested that environmental MPs are now exceeding the safe planetary boundaries. For instance, the recent discovery of high-level MPs in human brain tissues has attracted significant news coverage. The White House recently announced a new strategy to tackle plastic pollution problems.To address the MP challenges, it is essential to accurately detect and identify MPs in environment. Various methods, such as optical detection (e.g., fluorescence microscopy and flow cytometry) and chemical analysis (e.g., Fourier transform infrared spectroscopy, Raman spectroscopy, and thermal degradation-based methods), have been developed. However, current methods are limited by sensitivity. For example,no methods are available to measure very small single MPs (smaller than 5 µm) but very small MPs are highly abundant in environmentwith very strong health impacts. Furthermore, current methods need complicated, laborious, and cross-contamination prone sample preparation. As a result, no standardized methods are available to enable the comparison of MP data from two different measurements. Therefore, developing new methods that can address those measurement problems is important.This project develops a radio-frequency (RF) flow cytometry sensing technology to overcome the difficulties of current MP measurement methods. The technology is referred to as MP-RFC. MP-RFC directly samples environmental water, removes large debris, concentrates MPs, measures the dielectric property of each MPs, uses artificial intelligence (AI) to analyze and count each MP in the sample, and wirelessly informs the intended audience about the results. The whole process is automated without using any chemicals or invasive actions.The success of MP-RFC based MP sensing techniques will provide a new and standardized method for small MP measurement. The method is expected to be robust, affordable, field-deployable, and user-friendly. Therefore, the obtained techniques will significantly facilitate the efforts in filling MP knowledge gaps, includingMP source, transport, fate, and impact in environment, food chain, water cycle, and human body. It provides an affordable technique for long-term and/or in-situ monitoring of MPs, such as monitoring MPs in wastewater, air, and soil in remote areas and extreme environments. As a result, the proposed MP-RFC will help provide sufficient data that are accurate, in-situ, and near real-time for the society and regulatory agencies to take appropriate actions against the growing MP pollution problem.