This document is downloaded from Outstanding Academic Papers by Students (OAPS), Run Run Shaw Library, City University of Hong Kong. Title Microplastics pollution on soft shores in Hong Kong Author(s) Ng, Wing Yi (伍詠怡) Ng, W. Y. (2016). Microplastics pollution on soft shores in Hong Kong Citation (Outstanding Academic Papers by Students (OAPS), City University of Hong Kong). Issue Date 2016 URL http://dspace.cityu.edu.hk/handle/2031/85 This work is protected by copyright. Reproduction or distribution of Rights the work in any format is prohibited without written permission of the copyright owner. Access is unrestricted. CITY UNIVERSITY OF HONG KONG Department of Biology and Chemistry BSc (Hons) in Environmental Science and Management Project Report Microplastics Pollution on Soft Shores in Hong Kong By NG Wing Yi October 2016 1 _____________________________________________________________________________________________________________________________________________________ This document is downloaded from Outstanding Academic Papers by Students (OAPS), Run Run Shaw Library, City University of Hong Kong Table of content 1. Abstract ................................................................................................................................. 5 2. Introduction .......................................................................................................................... 6 2.1 Background of Microplastics Pollution.................................................................... 6 2.1.1 History of Microplastics ................................................................................. 6 2.1.2 Sources of Microplastics ................................................................................. 7 2.1.3 Microplastics Pollution in Hong Kong .......................................................... 8 2.2 Previous Researches on Microplastics Pollution ..................................................... 9 2.2.1 Previous Researches in Foreign Countries ................................................... 9 2.2.2 Previous Researches in Hong Kong ............................................................. 10 2.3 Aims and Hypotheses ............................................................................................... 11 3. Sampling and Analytical Assessment of Microplastics ................................................... 13 3.1 Collection Site ........................................................................................................... 13 3.2 Sediment Sampling .................................................................................................. 15 3.3 Extraction of Microplastics from Sediment Samples ........................................... 17 3.3.1 Heavy Liquid for Density Separation ......................................................... 17 3.3.2 Preparation of Zinc Chloride Solution ....................................................... 18 3.3.4 Organic Matter Digestion ............................................................................. 19 3.4 Identification of Microplastics ................................................................................ 22 3.4.1 Microscopic Examination ............................................................................. 22 3.4.2 Fourier-transform infrared (FTIR) Spectroscopy ..................................... 23 3.5 Particle Size .............................................................................................................. 25 3.6 Total Organic Carbon (TOC) Analysis .................................................................. 26 4. Results ................................................................................................................................. 28 4.1 Microplastics Abundance ........................................................................................ 28 4.2 Composition of Microplastics ................................................................................. 30 4.3 Chemical Nature of Microplastics .......................................................................... 35 4.4 Particle Size and Total Organic Carbon ................................................................ 40 5. Discussion............................................................................................................................ 42 5.1 Comparison of Microplastics Pollution between Western and Eastern Shores . 42 5.3 Comparisons with Previous Studies ....................................................................... 50 5.3.1 Comparisons with Local Beach Surveys of Microplastic Pollution ......... 50 5.3.2 Comparisons with Other Countries of Microplastics Pollution ............... 52 5.4 Errors, Limitation and Improvements................................................................... 55 6. Conclusion .......................................................................................................................... 58 7. Acknowledgement .............................................................................................................. 59 8. References ........................................................................................................................... 60 3 _____________________________________________________________________________________________________________________________________________________ This document is downloaded from Outstanding Academic Papers by Students (OAPS), Run Run Shaw Library, City University of Hong Kong 9. List of Figures ..................................................................................................................... 74 10. List of Tables ..................................................................................................................... 76 11. Appendix ........................................................................................................................... 77 11.1 Microplastics Data Sheet ....................................................................................... 77 4 _____________________________________________________________________________________________________________________________________________________ This document is downloaded from Outstanding Academic Papers by Students (OAPS), Run Run Shaw Library, City University of Hong Kong 1. Abstract Microplastics (< 5 mm) in sediments from eastern waters and western waters in Hong Kong were investigated to evaluate the significance of the Pearl River in microplastic pollution. Sediments and microplastics were collected from four sandy beaches in Hong Kong. They were Luk Keng Tsuen (LKT) and Sha Lo Wan (SLW) in the western part of Hong Kong in close proximity to the Pearl River estuary and Sha Tsui (ST) and To Tei Wan (TTW) in the eastern waters. Microplastics were extracted from sediments by density separation using zinc chloride solution (d > 1.6 g cm−3). 47.8 ± 12.1 particles per kilogram in ST, 5.0 ± 1.3 particles per kilogram in TTW, 29.0 ± 17.7 particles per kilogram in LKT and 8.5 ± 0.5 particles per kilogram in SLW were found under an optical microscope, respectively. These microplastics were identified by attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. Polyethylene, nylon66, polyester (alkyd resin), polystyrene, polypropylene and poly (methyl methacrylate) were characterized to be major types of the microplastics. Results reported herein showed that the amount of microplastics at ST were significantly higher than at TTW and SLW. The results also indicated that instead of the Pearl River, local sources, which were mainly from various anthropogenic activities, were the major contributors of microplastics pollution. The results, however should interpret with caution due to limited number of sampling sites. A more comprehensive study involving more beaches is recommended if time is allowed. 5 _____________________________________________________________________________________________________________________________________________________ This document is downloaded from Outstanding Academic Papers by Students (OAPS), Run Run Shaw Library, City University of Hong Kong 2. Introduction 2.1 Background of Microplastics Pollution 2.1.1 History of Microplastics For the last century, plastics have been an indispensable element for innovation and have contributed to the development and progress of the world. Being a lightweight, durable, strong and excellent thermal and electrical insulator, plastics are ideally suited for a variety of applications. In fact, the worldwide production of plastic has increased from 1.5 million tons in 1950 to 311 million tons in 2014 (PlasticsEurope, 2015). The extensive use of plastic has caused a dramatic increase in the plastic waste which becomes a global environmental issue. Ingestion of plastics by birds (Cadee, 2002; Mallory, 2008) and turtles (Bugoni & Krause, 2001; Tomas and Guitart, 2002; Mascarenhas ., 2004) is extensively recorded worldwide and more than 40% of marine bird species are found to ingest plastics (Rios & Moore, 2007). A particular concern in recent years is the occurrence of plastic debris which cannot be seen by naked eyes known as microplastics in the oceans. At present, the definition of microplastics is still under debate. In 2008, the National Oceanographic and Atmospheric Agency (NOAA) of the US established a broader working definition to include all plastic particles less than 5mm in diameter (NOAA, 2008). The larger plastics (1 ‒ 5 mm)