Seminar

Microplastics are ubiquitous and affect all environments. In recent years it was found that rivers play a major role in the transport of microplastics to the ocean. Research indicates that human influence is a key factor for microplastics pollution in rivers and freshwater bodies. In this study the microplastics pollution of the Wu River network in central Taiwan was investigated. The tributaries have their origin in the unpopulated mountainous areas, but their downstream sections enter the densely populated urban areas. This makes them ideal to study the impact of human activities. Samples were collected from different river sections using a manta-net. On average 10,000 liters of water were filtered for each sample. Microplastic particles in the size range of 0.3 to 5 mm were visually extracted and counted. Results show a clear distinction between unpopulated mountainous areas and densely populated urban areas. The average number of microplastics the mountain areas ranged from 0 to 0.18 pcs/m³, whereas in the urban areas the range was up to 169.46 pcs/m³. A spatial pattern could be observed too. When the river enters the urban area, the number of microplastic particles suddenly increased and reached its maximum further downstream. Storm sewers had a positive correlation with the number microplastic particles. It is likely that untreated water from urban areas, which is flushed through storm sewers, is one of the major contributors for river pollution.

Additional information: Dr. Christelle NOT, cnot@hku.hk