Abstract:
The aim of this study is to have a better view of microplastic contamination in the environment and how urban runoff plays an important role in transporting microplastics from their sources to the receiving environment. The study also focused on identifying the existing stormwater management devices raingarden’s ability to manage microplastic contamination in urban runoff prior to the receiving water systems. Methods of counting microplastics were reviewed and a new method was proposed.
Two raingarden columns were built in the laboratory. The number of microplastics in the collected real runoff was tested by those raingarden columns. The microplastics transportation in soil was mimicked in the raingarden columns by spike samples.
A new microplastic counting method by image analysis was introduced in the study. Two urban runoff pre-treatments were used before image analysis to increase the counting accuracy. Density separation was used to remove inorganic matters and Fenton Oxidation was used to remove organic matters in the runoff.
Three findings of this research study are concluded. Firstly, raingardens are good urban runoff management devices for blocking microplastics into receiving water bodies. Secondly, the two pre-treatments proposed effectively removed most of the wastes (both inorganic and organic matters) in urban runoffs. Thirdly, the proposed image analysis method can be a new method of counting microplastics. However, more work needs to be done to improve the precision of the image analysis method.
