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First evidence of microplastics in atmospheric deposition over the Gulf of Thailand: Distribution, characteristics, and ecological risk
(2026-09-15)
Chinfak, Narainrit
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Gunasekaran, Kannan
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Jandang, Suppakarn
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Li, Qipei
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Sricharoenvech, Piyaporn
Microplastics (MPs) have been extensively studied in aquatic environments; however, their occurrence in atmospheric deposition remains poorly understood. This study provides the first insights into the distribution of MPs in wet deposition across different locations and evaluates their potential environmental risks in the Gulf of Thailand (GoT). The ocean is likely a sink for MPs, with approximately 10% of the total MPs in atmospheric deposition detected in oceanic rainwater. MP abundances in terrestrial rainwater, including urban and agricultural rainwater (62.70 ± 15.89 items/m2 and 29.37 ± 12.29 items/m2, respectively) were significantly higher than those in the GoT rainwater (9.72 ± 3.70 items/m2) ( p = 0.001), with greater MPs abundance observed in the urban center. MPs exhibited similar morphological (shape and color) and compositional characteristics across all locations. Fibrous MPs (100–500 μm) dominated urban (42%) and agricultural (55%) rainwater, whereas smaller fibers (<100 μm) were predominant in the GoT (69%). White and black were the dominant colors found in both terrestrial and GoT rainwater. Low-density polymers (PE, PP and PS) were the most frequently detected polymers, comprising up to 80% of the total MPs. Among them, PE was predominant, accounting for 48%, 51%, and 62% of all MPs identified in urban, agriculture and the GoT rainwater, respectively. Ecological risk assessment indicated a minor potential ecological risk associated with MPs in wet deposition. Future studies investigating both wet and dry deposition, as well as factors influencing MP distribution and transport in the GoT, are needed to support transport modeling, identify potential sources, and assess the impact of climate forcing on MP distribution.
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Microplastic sources and distribution in tropical mangroves: Natural and planted systems in China
(2026-08-01)
Pradit, Siriporn
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Loh, Pei Sun
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Jitkaew, Preyanuch
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Noppradit, Prakrit
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Nitiratsuwan, Thongchai
Mangrove forests sequester microplastics (MPs); however, the long-term accumulation efficiency of planted and natural mangrove forests remains poorly understood. MP pollution poses a pervasive threat to coastal ecosystems worldwide. We reconstructed the burial record of MPs in 1-m sediment cores from two contrasting mangrove ecosystems in China: a planted forest on Ximen Island (four cores) and a natural forest in Fangchenggang (two cores). MPs were present in all sediment layers and identified by stereomicroscope and micro-Fourier transform infrared spectroscopy. Fibers overwhelmingly dominated the MP assemblage (88.6–98.2% in planted mangroves; 90.8–92.6% in natural mangroves), with the polymer profile (rayon, polypropylene, polyethylene terephthalate) strongly implicating local fishing and aquaculture activities as primary sources. MP contamination dates to at least 1963 in the natural forest and 1989 in the planted forest, thereby providing a >50-year and >30-year pollution record, respectively. Although total MP abundance exhibited no simple increasing trend with depth, the natural mangrove sequestered a significantly ( p < 0.001) higher MP burden than the plantation. The co-occurrence of an early onset and great contamination magnitude in the natural forest underlines superior particle-trapping efficiency of its mature, complex vegetation structure. Therefore, natural mangroves are critical long-term archives for coastal MP pollution; their conservation is vital for carbon sequestration and mitigating coastal plastic pollution.
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Microplastics and phthalate esters in tropical estuaries of Hainan Island, China: Spatial distribution and interrelationship patterns
(2026-07-15)
Cai, Bing
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Shen, Jiashun
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Long, Xinrui
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Liu, Ruifeng
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Zhou, Yanyu
Microplastics (MPs) and phthalate esters (PAEs) are widespread plastic-related contaminants in aquatic environments, yet their co-occurrence in tropical estuarine ecosystems remains limited. In this study, MPs and PAEs were simultaneous investigation in surface seawater and sediments from 65 sites across 10 estuarine regions of Hainan Island, China during the spring dry season of 2024. MPs were examined using stereomicroscope followed by micro-Fourier Transform Infrared Spectrometer (μ-FTIR), while the PAEs were analyzed by solid-phase extraction and Gas Chromatography-Mass Spectrometry (GC-MS). Both MPs and PAEs were widely detected throughout the study area. In seawater, MPs abundances and PAEs concentrations ranged from 1.1 to 15.1 items/L (mean: 5.3 ± 2.6 items/L) and 158.2 to 2317.6 ng/L (mean: 1023.7 ± 448.3 ng/L), respectively. In sediments, MPs abundance and PAEs concentrations ranged from 60 to 1053.3 items/kg dry weight (dw) (mean: 264.6 ± 189.1 items/kg dw) and 45.8 to 863.7 μg/kg dw (mean: 337.9 ± 179.6 μg/kg dw), respectively. In terms of composition, polyethylene terephthalate (PET) and cellulose were detected as primary MP polymers, while di (2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) were identified as major PAE congeners in both seawater and sediments. Correlation analysis revealed significant positive correlations between the abundances of MPs and the concentrations of PAEs in both seawater and sediments, with a stronger correlation observed in sediments (r = 0.57, p < 0.01) than in seawater (r = 0.40, p < 0.01). Overall, these findings provide a regional dry-season baseline for the co-occurrence of MPs and PAEs in Hainan Island's estuarine–coastal environments and support future monitoring and source-oriented pollution management.
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Genome and transcriptome mining of the corazonin (Crz)-like peptide and gonadotropin-releasing hormone (GnRH)-like peptides in the spotted Babylon, Babylonia areolata
(2026-06-01)
Saetan, Uraipan
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Kornthong, Napamanee
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Duangprom, Supawadee
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Tanasawet, Supita
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Sukketsiri, Wanida
The Spotted Babylon (Babylonia areolata) is an economically marine species in Thailand and other Asian countries. Due to the high demand for its meat, improving aquaculture practices for this species is essential. Regarding the lack of neuroendocrine control of reproduction in this species, we performed transcriptome analysis of the central nervous system and ovaries, and we searched against the reported genome of this animal species to find out the neurohormones. Here, we reported the identification of corazonin (ba-Crz)-like and gonadotropin-releasing hormone (ba-GnRH)-like mRNAs in B. areolata. The ba-Crz-like mRNA encoded mature ba-Crz-like peptide as QNYHYSNGWHP. Two ba-GnRH-like mRNAs encoded ba-GnRH-I-, and ba-GnRH-II-like peptides containing active peptides as QIHFSPTWGT and QIHFSHSWGT. Two introns were found in the ba-Crz-like gene while one intron was present in each ba-GnRH-like gene. These three peptides were phylogenetically placed in the molluscan Crz and GnRH clades. RT-PCR of these three mRNAs revealed their ubiquitous expressions across various organs, with all three predominantly expressed in ganglia, which was further confirmed by in situ hybridization of the cerebral ganglia. Immunohistochemistry showed positive signals for the Crz-like peptide in both the CNS and ovaries. To examine expression across ovarian cycle, the ba-Crz-like, and ba-GnRH-I-like mRNAs were consistently expressed in the CNS and ovaries of both immature and mature female snails, while the ba-GnRH-II-like mRNA significantly reduced its expression in the CNS of mature snails. Conclusively, this study was preliminary to report on the existence of GnRH/AKH/Crz peptides in the B. areolata, Further characterization of their receptors and biological functions is ongoing to ensure the GnRH, AKH, and Crz identification in this species.
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Distribution and chemical composition of atmospheric aerosols over the Gulf of Thailand during the southwest monsoon
(2026-05-01)
Kayee, Jariya
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Sompongchaiyakul, Penjai
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Das, Reshmi
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Wang, Xianfeng
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Chinfak, Narainrit
Marine aerosols were collected over the Gulf of Thailand (GOT) during the 2018 southwest monsoon on board the M.V. SEAFDEC2 while sailing. Water-soluble inorganic ions (i.e., Na+, NH<inf>4</inf>+, K+, Mg2+, Ca2+, Cl−, NO<inf>3</inf>−, and SO<inf>4</inf>2−) and elemental concentrations (i.e., Al, As, Ba, Ca, Cd, Cu, Cr, Fe, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were determined to investigate their distribution patterns in order to evaluate the influence of particle sources on the chemical properties of atmospheric aerosols. During the southwest monsoon, the wind predominantly blows over the Indian Ocean to the GOT. Correspondingly, our results indicated that coarse particles are dominated by sea salts. Cl− and Na+ are the major ions, accounting for ∼64.8% (range: 51.2–84.3%) of total ions in the coarse mode particles. The strong correlation between Cl− and Na+ ( r = 0.999) along with the Cl/Na ratio (1.5, range: 0.66–2.00) suggest sea salt origin. Enrichment factor (EF) values indicate that elements are originated from oceanic, crustal, and anthropogenic sources. The oceanic source (Sr, Ca, Mg and Na) explains 95% (range: 81–99%) of total elements in the aerosols. Elements such as Al, Fe, Mn and Ba explain 4.6% of the total elements. These elements associate with the crustal source. Only a minimal amount (0.63%, range: 0.02–4.5%) of the total elements is originated from anthropogenic activities over or nearby the GOT as shown by loading of As, Cd, Cu, Cr, Ni, Pb, V and Zn.
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Effects of cuttlebone powders and their structured calcium compounds against glucocorticoid-induced osteoporosis via MAPK signaling-mediated bone formation
(2026-04-01)
Woonnoi, Wanwipha
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Chinfak, Narainrit
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Tanasawet, Supita
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Saetan, Jirawat
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Klaypradit, Wanwimol
The effects of dried and calcined cuttlebone powders (DCB and CCB, respectively) and their structured calcium compounds (DCB-OH, DCB-Lac, DCB-CiMa, CCB-OH, CCB-Lac, and CCB-CiMa) on MC3T3-E1 osteoblasts were investigated in vitro . Cytotoxicity analysis using the MTT assay revealed that lower concentrations (10–100 μg/mL) of all compounds were non-toxic, whereas higher concentrations (250–1000 μg/mL) showed dose-dependent cytotoxic effects. Using dexamethasone-induced osteoporosis-like MC3T3-E1 cells, cuttlebone-derived compounds significantly enhanced matrix mineralization as well as alkaline phosphatase (ALP) mRNA expression and activity, indicating restoration of osteoblast function. Additionally, treatment with all cuttlebone compounds reduced dexamethasone-induced apoptosis, demonstrating cytoprotective effects. Gene expression analysis showed suppression of ER stress markers ( CHOP, GRP78, ATF4 ) by most compounds, suggesting attenuation of ER stress-related osteoblast dysfunction. Osteoblast-related genes linked to matrix remodeling and bone formation ( MMP2, MMP9, COL1A1 ) were modulated; treatments generally downregulated MMP2 and upregulated COL1A1 expression. Key osteogenic transcription factors and markers ( BMP4, OC, OSX, RUNX2 ) decreased by dexamethasone were significantly upregulated by cuttlebone compounds, supporting enhanced osteoblast differentiation. Protein phosphorylation studies revealed that these compounds decreased the expression of pERK and p-p38, pathways that are often associated with impaired osteogenesis under glucocorticoid stress. Collectively, these findings demonstrate that cuttlebone powders and their structured calcium compounds mitigate dexamethasone-induced osteoporotic changes in MC3T3-E1 cells by enhancing cell viability, promoting osteoblast differentiation, and reducing apoptosis and ER stress, effects that are associated with suppression of MAPK pathway activation. This finding suggests a possible role in alleviating glucocorticoid-induced dysfunction in MC3T3-E1 osteoblasts and indicates potential relevance for future development as functional food ingredients or nutraceuticals for bone health.
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Spatial distribution, abundance, and characterization of emerging plastic forms in binational coastal ecosystems
(2026-04-01)
Gunasekaran, Kannan
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Ehlers, Sonja M.
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Mghili, Bilal
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Chinfak, Narainrit
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Charoenpong, Chawalit
The persistence of plastic waste in marine environments drives the formation of novel plastic forms through prolonged exposure to environmental conditions and interactions with organic and inorganic materials. This study is the first binational assessment of the spatial distribution, abundance, and characterization of three emerging plastic forms-plasticoncrete, plastimetal and plastisessiles on beaches in India and Thailand. A total of 29 distinct plastic forms were identified, including 11 plasticoncretes, 8 plastimetals and 10 plastisessiles. Plasticoncretes composed of widespread polyethylene (PE), polypropylene (PP) and polyamide (PA) fibres and a polyvinyl chloride (PVC) fragment hardened in concrete. Plastimetals consisted of metal rods rusted with PE, PP and polyester (PEST) fibres. Plastisessiles are formed by PA monofilament lines, PE fishing ropes and PP fibres attached to sessile invertebrates, including oysters and mussels. The plastic forms predominantly contained fibers (93.75%), which are mainly blue in colour, ranging from 2.3 cm to 43.5 cm in length, with PE and PP as the dominant polymers. Floating tests confirmed that all the plastic forms sank, suggesting their local formation, limited mobility and reduced longevity in the water column. This study provides insights into occurrence and characteristics of these plastic forms in coastal environments, highlighting the need for extensive research and monitoring in the Indian and Thailand coastal environment to understand plastic form distribution comprehensively.
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Occurrence of microplastics in farmed and wild snails along the coasts of Thailand: Implications for consumer exposure and health risks
(2026-03-01)
Saetan, Jirawat
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Chinfak, Narainrit
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Gunasekaran, Kannan
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Li, Qipei
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Zhang, Jing
Microplastics (MPs) pollution has become a critical global issue due to its harmful effects on the environment and public health. This study investigates the abundance of MPs in commercial spotted babylon snails ( Babylonia areolata ) from farmed and wild populations along the coasts of Thailand, evaluates daily MP exposure for consumers, assesses potential health risks, and explores strategies to mitigate MP exposure and associated human health risks. MP occurrence ranged from 55 % to 99 % in both farmed and wild B. areolata , with an average abundance of 1.17 ± 1.02 items/individual and 2.64 ± 2.17 items/individual, respectively. Wild B. areolata exhibited significantly higher MP levels than their farmed counterparts, but MP abundance in wild snails decreased by approximately 70 % following a 72-h depuration period. The most common MPs (<1000 μm) were small black and blue fibers, primarily composed of polyethylene terephthalate and polyester. The estimated daily MP exposure for B. areolata consumers was 0.005 items/person/day with a minimal health risk after the clearance experiment. As a mitigation strategy, we recommend acclimating B. areolata in MPs-free water systems for 2–3 days to reduce MP-related health risks.
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Potential of marine litter for range expansion of the invasive mussel Mytella strigata (Hanley, 1843) along the Indian coast
(2026-01-01)
Gunasekaran, Kannan
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Mghili, Bilal
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Sompongchaiyakul, Penjai
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De-la-Torre, Gabrique Enrique
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Machendiranathan, Mayakrishnan
Marine litter is a key vector of dispersing invasive species in the marine environment. However, our knowledge of the ecological interactions between these species and litter is still incomplete. Here, we investigated the substrate preferences and physical characteristics of marine litter colonized by the invasive mussel Mytella strigata, and explored the role of litter in the population expansion of this species along the Tamil Nadu coast, India. A total of 72 fouled debris were observed along the study areas. The majority of the fouling litter was composed of plastic (87.5 %), followed by rubber (4.2 %), wood (4.2 %), glass (2.8 %) and metal (1.4 %). A total of 2637 individuals of M. strigata were recorded on the marine litter, with recruitment on plastic substrates. Particularly, M. strigata were most common on large marine litter with irregular or cylindrical shapes, rough surfaces and transparent, blue or green colours. Our work provides evidence that marine litter can play a role in the reproduction of this invasive mussel. Consequently, M. strigata benefits from the litter substrates and the habitat complexity created by anthropogenic materials along the Tamil Nadu coast, enhancing its survival and reproduction. This could promote the expansion of the M. strigata population and thus affect the composition and structure of the marine ecosystem.
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Anthropogenic Impacts on the Distribution of Dissolved Nutrients at 4 Major River Mouths Discharging into the Inner Gulf of Thailand
(2026-01-01)
Srisaard, Suparat
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Sompongchaiyakul, Penjai
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Ubonyaem, Tanakorn
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Charoenpong, Chawalit
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Chinfak, Narainrit
Anthropogenic activities have been identified as key contributors to nutrient loading and phytoplankton blooms along the eastern coast of the Inner Gulf of Thailand (inner GoT). This study provides a comparative analysis of dissolved nutrient levels and distributions at the river mouths of 4 major basins discharging into the inner GoT in the same period: Maeklong (MK), Thachin (TC), Chaophraya (CPY), and Bangpakong (BPK). Physicochemical parameters were measured and dissolved nutrients, in inorganic and organic forms, were examined using spectrophotometric methods. The study was conducted through monthly and seasonal monitoring (dry and wet seasons) in 2019. Monthly sampling focused on spatial variation between upstream and downstream stations of each river, while additional sites (6-8 stations) at the river mouths were used to monitor vertical profile changes during dry and wet seasons. Results indicated that anthropogenic influences significantly affected nutrient concentrations and their spatial distribution. TC exhibited the highest average dissolved inorganic phosphorus (9.39 ± 4.83 µM) and lowest dissolved oxygen (1.43 ± 1.06 mg L−1), reflecting high domestic waste input, organic pollution, and hypoxic conditions. Exceptionally high dissolved organic nitrogen concentrations in TC (284 ± 62.5 µM) and CPY (304 ± 124 µM) suggested metropolitan areas as major DON sources, with the potential to enhance phytoplankton growth in the inner GoT. In BPK, dam operations altered hydrological dynamics and nutrient distribution, while MK, the least disturbed basin, showed the lowest nutrient levels. A negative correlation between nutrient concentrations and salinity, along with vertical nutrient profiles, indicated that water mixing was a dominant process controlling nutrient distribution at all river mouths. This study highlighted the anthropogenic influence and the role of nutrients especially DON in the inner GoT, providing insights into eutrophication, phytoplankton blooms, and deoxygenation-essential for sustaining fisheries and informing site-specific environmental regulations.

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