On the 9th, seen from the deck of a passenger ferry, Gauido in Taean Coast National Park looked like an unspoiled island. From the bow before reaching the pier, Sinjangbeol Beach on Gauido looked beautiful. A white stretch of sand untouched by people blended with the blue sea.

After about 25 minutes, we arrived at the Gauido pier, transferred to a fishing boat, circled about half the island, and headed for Sinjangbeol Beach. As we drew closer, pieces of trash that had been invisible from afar came into view one by one. After a difficult landing, we found plastic bottles, Styrofoam, and plastic buoys scattered across the beach. With every step, discarded fishing gear tangled with nets bumped against our feet. It looked as if the entire beach had been buried under a heap of trash.

A belt of trash stretched in a long line along the roughly 400 m beach. Trash deeply buried in the sand did not budge even when pulled with force. Waste swept in by large waves was wedged firmly into crevices between rocks.

Kim Jong-myeong, a team leader at the Taean Coast National Park Office of the Korea National Park Service, which is responsible for monitoring trash along the Taean coast including Gauido, said, “Foreign-made plastic buoys account for about 10% of the marine debris on Gauido,” and added, “If foreign PET bottles are included, the amount of foreign-sourced trash is even greater.”

Among the trash that stood out most on Sinjangbeol Beach were plastic PET bottles. In fact, according to analysis by the Korea National Park Service using unmanned aerial vehicle (drone) footage and artificial intelligence (AI), of the 19,701 items of marine trash identified on Gauido as of August, plastic bottles numbered 6,527, accounting for 33.1% of the total. Not only domestic beverage PET bottles but also bottles bearing Chinese labels for Binghongcha and PET bottles for carbonated water with Russian writing were easy to find.

Aside from PET bottles, most items were ‘fishing trash’ generated in the course of fishing, such as Styrofoam and plastic buoys and discarded fishing gear. Small plastic fragments, broken into pieces, sloshed with the waves, unable to get out from among the shallow coastal rocks. There were many Chinese plastic buoys as large around as an adult waist. China has recently been using recyclable plastic buoys in marine aquaculture to reduce Styrofoam waste. Those ‘eco-friendly’ buoys from China have flowed into Korea and become trash.

Kim said, “In addition to fishing, a considerable amount of trash is dumped from large vessels that pass through the Taean area,” and noted, “Although it is hard to distinguish, trash generated on ships also needs to be kept in mind when monitoring this area.”

No one felt like staying long on a beach covered entirely in trash. When we returned to the pier to look around the interior of the island, this time marine trash floating along the coast caught the eye. Colorful plastic bags and Styrofoam fragments were driven ashore by the waves.

Island residents are growing weary of the endless inflow of trash. Through a senior employment program, residents gather in small groups to collect it, but it is hard to keep up with how quickly it accumulates again. On a small island with only about 70 residents, the volume of trash is too much for the elderly population to handle.

Im Yeong-hwa, 76, who has run a guesthouse on Gauido since 2019, said, “The water here used to be so clean that it was called ‘the West Sea like the East Sea’,” and added, “The seabed is still clean, but there is so much trash washed onto the shore that it is unpleasant to look at.”

Gauido, which is inhabited, is relatively better off. Marine trash also inexorably washes up on uninhabited islands. According to the Korea National Park Service, between 800 and 1,300 items of trash are found every month on Mokgaedo, an uninhabited island. PET bottles make up 48.4%, or nearly half of all items. By weight, processed lumber (24.5%) and rope (15.2%) and Styrofoam buoys (14.9%) accounted for the largest shares.

On another uninhabited island, Hwachangdo, marine trash has been increasing every month. The number of items rose from 481 and 271.3㎏ in April to 1,309 and 2,621.5㎏ in August. In a place with no residents and no tourists, only trash is piling up.

Trash appears in various forms and at different scales on beaches around Taean as well. Monitoring by the Korea National Park Service at 19 beaches around Taean found that from April to August (excluding May), 47,055 items of coastal trash were tallied on-site. By count, PET bottles were the most common at 9,351 items (19.87%), while by weight, processed lumber totaled 35 t (43.37%), the largest share.

Marine trash in Korea has been increasing year by year. According to the Ministry of Oceans and Fisheries, the nationwide volume of collected marine waste rose from 120,736 t in 2021 to 144,615 t last year. At the four national marine parks nationwide, collected marine waste also jumped sharply from 708 t in 2018 to 2,158 t in 2022.

However, collection figures alone make it difficult to determine the actual amount of marine trash accumulated on coasts. While the amount collected is tallied, there is a lack of data showing how much is piled up and where it is concentrated. Responsibility for management is divided among the Ministry of Climate, Energy and Environment and the Ministry of Oceans and Fisheries and local governments, making it difficult to systematically understand the scale and distribution of marine trash.

Since April, the Korea National Park Service has been filming monthly drone footage and using AI to analyze the amount, types, and condition of marine trash at 22 locations in Taean National Park, including three islands and 19 beaches such as those on Gauido, covering a section of about 30㎞. The goal is to identify the distribution of trash through repeated monitoring.

Han Chang-joon, head of the Taean Coast National Park Office, said, “By using drone photography and AI analysis, we are moving beyond the previous approach that relied on visual surveys to monitor the status of coastal trash,” adding, “As data accumulates, we will be able to concentrate budgets and personnel where they are needed to respond to marine trash.”