Microplastics in mangrove sediments at Maeklong river mouth, Samut Songkhram province

Abstract

Microplastics are omnipresent in our environment. Living organisms were affected by microplastic pollution. This study was investigated microplastic in mangrove environments because there are accumulated various substances from land and sea. Moreover, mangrove is an important ecosystem that is a habitat for marine life and benthic organism. Our study area is the Maeklong River mouth, Samut Songkhram Province, Thailand. Surface sediments from 3 stations were collected from the Maeklong River area and 2 core sediments were collected from the Maeklong River mouth and the Queen Sirikit Park. Sediment samples were analyzed by Loss on ignition (LOI) and grain size distribution. Microplastics were digested and observed their characteristics. Surface sediments from the Maeklong River mouth were found microplastic with average 580 ± 87 item per kilogram. The abundance of microplastic at far away site from river mouth was lower amount than at river mouth site. Previous studies in the Klong Khon tidal canal showed that the number of microplastic from the Klong Khon was higher than the Maeklong River. According to the Maeklong River flow are turbulent that affected on sediment also other particle to accumulate. 142 cm core was found microplastic ranging from 0 – 5,200 items per kilogram that concentration was decreasing with more depth. Location and grain size had an influence in the accumulation of microplastic in sediment. The most common microplastics that found in this study were 0.1 – 1.0 mm in size. The fiber was the abundance shape of microplastic. Polyester is the prevalent type of plastic in this study, the result refers to the source that can generate microplastic into environment such as wastewater from washing process and material from fishing.