Briefly describe the characteristics of marine pollution.

Firstly, there are numerous sources of pollution. In addition to human activities in the oceans, various pollutants generated by human activities on land and in other areas also end up in the oceans through river runoff, or via atmospheric dispersion and precipitation such as rain and snow. Secondly, its persistence is high; the ocean is the lowest-lying area on Earth, and it cannot, like the atmosphere or rivers, see pollution reduced or even eliminated through a single storm or flood season. Once pollutants enter the ocean, it is difficult to remove them. Substances that cannot dissolve or are not easily decomposed accumulate in the ocean, and they often pose a potential threat to humans through biological accumulation and the food chain. Third, it has a wide spread range. The world’s oceans form an interconnected whole; pollution that occurs in one sea area often spreads to surrounding waters and may even reach adjacent oceans, with some of its long-term effects affecting the entire globe. Fourth, it is difficult to prevent and control, and its hazards are severe. Ocean pollution takes a long time to accumulate, and it is not easy to detect it in a timely manner. Once pollution occurs, it requires long-term efforts to eliminate its effects, and the costs associated with remediation are high. The harm caused by such pollution affects various aspects, especially the toxic effects on humans, which are extremely difficult to completely eliminate.

1. Wide range of pollution sources 2. Persistent nature 3. Large spread area 4. Complex control requirements

Due to the unique characteristics of the ocean, marine pollution differs significantly from air and land pollution. Its prominent features are as follows: First, there are numerous sources of pollution; not only do human activities at sea contribute to ocean pollution, but pollutants generated from human activities on land and in other areas also end up in the ocean through river runoff, atmospheric dispersion, and precipitation such as rain and snow. Second, marine pollution persists over time, as the ocean is the lowest-lying area on Earth. Unlike the atmosphere and rivers, where pollutants can be removed or dispersed after a heavy rainstorm or during a flood season, this does not happen in the ocean； Once pollutants enter the ocean, it is difficult to remove them. Substances that cannot dissolve or decompose easily accumulate in the ocean, and through biological accumulation and the food chain, they pose a potential threat to humans. Thirdly, pollution spreads over a wide area; the world’s oceans are interconnected, so once one area is polluted, the contamination often spreads to surrounding areas, and in some cases, its effects can even reach across the globe. Fourthly, it is difficult to prevent and control such pollution, and its consequences are severe. Ocean pollution develops over a long period of time, making it hard to detect in a timely manner. Once pollution occurs, it takes a long time to address its effects, and the costs associated with cleanup are high. The harm caused by this pollution affects various aspects, especially the toxic effects on human health, which are difficult to completely eliminate.