Relative contributions of different local sources to riverborne microplastic in a mixed landuse area within a tropical catchment

Hui Ling Chen; Sivathass Bannir Selvam; Kang Nee Ting; Kim Yeow Tshai; Christopher Neil Gibbins

doi:10.1016/j.envres.2022.112972

Relative contributions of different local sources to riverborne microplastic in a mixed landuse area within a tropical catchment

Environ Res. 2022 Jul:210:112972. doi: 10.1016/j.envres.2022.112972. Epub 2022 Feb 24.

Authors

Hui Ling Chen¹, Sivathass Bannir Selvam², Kang Nee Ting³, Kim Yeow Tshai⁴, Christopher Neil Gibbins⁵

Affiliations

¹ School of Environmental and Geographical Sciences, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor, Malaysia. Electronic address: khby6chl@nottingham.edu.my.
² School of Environmental and Geographical Sciences, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor, Malaysia. Electronic address: Sivathass.bannir@nottingham.edu.my.
³ School of Pharmacy, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor, Malaysia. Electronic address: Kang-nee.ting@nottingham.edu.my.
⁴ Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor, Malaysia. Electronic address: Kim-yeow.tshai@nottingham.edu.my.
⁵ School of Environmental and Geographical Sciences, University of Nottingham Malaysia, Jalan Broga, 43500, Semenyih, Selangor, Malaysia. Electronic address: Christopher.gibbins@nottingham.edu.my.

PMID: 35219629
DOI: 10.1016/j.envres.2022.112972

Abstract

Information on the relative contributions of microplastics coming from different sources is important to help prioritise measures to reduce river contamination levels and limit human and ecological health risks. This paper reports on work which aimed to quantitatively assess the relative concentrations and types of microplastic delivered from differed sources to a second order river. The study was undertaken in a mixed landuse area within a rapidly urbanising catchment in Malaysia. Over a six-week period, water samples were collected from road culverts and drains in residential and industrial areas across the area to assess microplastic concentrations, while inputs from atmospheric deposition and wastewater treatment plants (WWTPs) were also quantified. Microplastic fibres and fragments were the dominant material in all sources, with the majority consisting of styrene-butadiene rubber and nylon. Culverts draining main roads were the main contributor to riverborne microplastic, delivering 42.20 ± 35.29 particles/L directly to the river channel. Road inputs were up to seven times greater than those from residential (8.53 ± 9.91 particles/L) and industrial (5.67 ± 4.88 particles/L) areas. The five WWTPs had removal efficiencies of between 30.95 ± 5.51% and 69.94 ± 22.17%, with their outflows delivering microplastics to the river in concentrations similar to those in uncontrolled residential and industrial drains. Atmospheric deposition across the study area was estimated to be 76.07 ± 32.85 particles/m²/day (=8.35 ± 5.11 particles/L). Mitigation strategies in the study area should focus on improving management of water draining roads, and re-routing discharges from domestic and industrial areas to WWTPs rather than allowing them to flow directly to the river. The low efficiencies of some of the WWTPs are not unusual, and indicate the need for additional water treatment to deal with microplastic present in wastewater.

Keywords: Atmospheric deposition; Industrial area; Microplastics; Residential area; Road runoff; Wastewater treatment plant.

MeSH terms

Environmental Monitoring
Humans
Microplastics*
Plastics
Rivers
Water Pollutants, Chemical* / analysis

Substances

Microplastics
Plastics
Water Pollutants, Chemical