Abundance and distribution of microplastics in tropical estuarine mangrove areas around Penang, Malaysia

Abstract

IntroductionThis study reports the abundance and distribution of microplastics in tropical estuarine mangrove areas in Penang, Malaysia.MethodsSamples were collected by using a neuston net and Ponar grab at four study sites (Seberang Perai, Kuala Muda, Penaga and Balik Pulau).Results and DiscussionA total of 8775 pieces were collected from the four sites, with abundance in coastal surface water, coastal bottom sediment, and estuarine sediment ranging between 201 ± 21.214 - 1407 ± 124.265 pcs/L, 255 ± 22.368 - 350 ± 25.892 pcs/kg, and 430 ± 7.234 - 4000 ± 29.174 pcs/kg respectively. Seberang Perai was found with the highest microplastics abundance in all compartments while fragment is the dominant morphology throughout all study sites. Stereomicroscopic analysis showed that microplastics are of numerous colours and irregular in shape while Field Emission Scanning Electron Microscope (FESEM) observed severe surficial weathering. Polyethylene is the most common identified polymer type via Fourier Transform Infrared Spectroscopy (FTIR) analysis and inorganic chemical compounds such as dimethylmercury were detected which pose a threat to organisms and the environment. The overall outcome suggests that human activities play a significant role in microplastic input into the estuarine environment and that the dominant polymer type in respective study site are closely related to the nature of human activities. This baseline study presents fundamental knowledge on microplastic pollution in the estuarine environment of Penang and encourages similar research to be conducted in the future for pollution control and management.

Prevalence of microplastics in Peruvian mangrove sediments and edible mangrove species

“…The microplastic abundance in this study (726±395.9 items/kg) was below those reported in mangrove sediments collected from Indonesia -2358 items/kg (Hastuti et al, 2019), Malaysia -3500 items/kg and ± 29.174 items/kg (Hamid et al, 2020;Tan and Mohd Zanuri, 2023), China with the highest abundance of 7900 items⋅kg 1 (Zuo et al, 2020), Colombia with a maximum concentration of 2745 ± 1978 items/kg (Garcés Ordóñez et al, 2019) and Brazil with 10,782 ± 7671 items/ kg (da Paes et al, 2022). However, our microplastics concentrations were greater than reported for mangrove ecosystems in Iran (34.5 items/kg) (Naji et al, 2019) and Singapore (62.7 ± 27.2 items/kg) (Mohamed Nor and Obbard, 2014).…”

Human activities altered the enrichment patterns of microplastics in mangrove blue carbon ecosystem in the semi-enclosed Zhanjiang Bay, China

“…A comparison of MPs abundance in dry mangrove sediments from different regions is shown in Table 2. The MPs abundance in ZJB is intermediate compared to foreign contamination, including Muara Angke Wildlife Reserve of Indonesia (28.09 ± 10.28 items/kg), Northern Persian Gulf of (19.5 to 34.5 items/kg), Kuala Muda of Malaysia (430 ± 7.234 items/kg), Penaga of Malaysia (940 ± 15.773 items/kg), Seberang Perai of Malaysia (4000 ± 29.174 items/kg) (Naji et al, 2019;Cordova et al, 2021;Tan and Mohd Zanuri, 2023). Compared with mangrove sediments from other regions of China, it was much higher than that of the North Yellow Sea (37.1 ± 42.7 items/kg), Beibu Bay (26.67 ± 9.43 to 239.94 ± 37.80 items/kg), inside the mangrove of Qinzhou Bay (42.9 ± 26.8 items/kg) (Zhu et al, 2018;Li et al, 2018a;Zhang et al, 2022), lower than outside the mangrove of Qinzhou Bay (2174.5 ± 2206.8 items/kg), Pearl River Estuary, South China (851 ± 177 items/kg), the fringe in Futian mangrove in Shenzhen Bay (2835 ± 713 items/kg) (Li et al, 2018a;Zuo et al, 2020;Duan et al, 2021).…”