Spatial-seasonal Variation in Microplastic Distribution at the Han River Estuary to the Coastal Area of Incheon, Korea
Bibliographic record
Abstract
As microplastics, which are synthetic polymers of less than 5 mm [1], have been emerged as a global environmental issue, lots of research have been conducted on spatial distribution and ecological impact in the marine [2][3][4][5], freshwater [6][7][8], and terrestrial environments [9,10].Several studies are also being investigated in the transition zone between freshwater and marine environments [11].However, there are still insufficient data to analytically survey their distribution of microplastics in there.In 2020, therein, the spatial-seasonal distribution of the suspended microplastics in the range from 330 μm to 5 mm has been monitored in the Han River Estuary extending to neighbored coastal area, Korea.For this purpose, microplastic samples have been collected from a total of 11 sampling stations located along the downstream of the Han River, Ganghwa Island, the Coast of Incheon, and Deokjeok Island.In each location, sampling has been carried out using a Manta trawl net (mesh size of 330 μm) while continuing to tow horizontally for 10 min.The collected samples were sieved through a 2 mm standard sieve, after which bigger pieces more than that were rinsed with distilled water and dried, while smaller particles were pre-treated by wet oxidation with hydrogen peroxide (H2O2) followed by density separation process with zinc bromide (ZnBr2) solution.Such separated unknown particles, possibly microplastics, were identified by Fourier transform infrared (FTIR) spectroscopy (VERTEX 80V, Bruker, Germany; Spotlight 400 FT-IR Imaging System, Perkin Elmer, USA).As a result, the average annual abundance of microplastics was estimated to be (2.15 ± 0.54) particles/m 3 in downstream of the Han River, (2.11 ± 0.60) particles/m 3 in Ganghwa Island, (6.12 ± 0.96) particles/m 3 in the Coast of Incheon, and 1.71 particles/m 3 in Deokjeok Island, respectively.Among them, Ganghwa Island, was found to be the most abundance possibly inflowed from land-originated marine debris, fishing activities, and their own hydrogeological contribution.In the case of Deokjeok Island, which is relatively farthest from the land, the abundance of microplastics was at the lowest level observed among others.Nonetheless, it was found that PS has been rapidly increased in July and August at the topmost extent due to probably lose or erroneous abandon of various fishing gears made in PS because of seasonally occurred heavy rains and highly rising sea waves.In this regard, for nearer the land of watershed, the spatial distribution of microplastics revealed in the order of polyethylene (PE) > polypropylene (PP) > polystyrene (PS) > copolymers (including plastic additives) > polyethylene terephthalate (PET)/polyester.In contrast, for the farthest as of Deokjeok Island, it showed that PS was composed of at the highest proportion of 58.5% among others.In the aspect of size distribution, type of microplastics showed at the different manner as PS was mainly ranged in 2~5 mm, while PE and PP were dominantly sized in 330 μm~2 mm.In conclusion, it was confirmed that microplastics could be detected more in coastal water close to land, and there is a clear difference depending on the inflow routes of microplastics and formation mechanism.This study would be applied to the effective management of microplastics for a sustainable environmental system.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".