How long does trash last in the sea?

On our list, Glass jar lasts longest: > 1,000,000 years. Next come Tin foil (> 1,000 years) and Fishing line (> 600 years).

On our list, Cardboard box breaks down fastest: > 2 weeks. Next come Paper bag (> 1 month) and Cloth T-shirt (> 1 month). Even these can harm sea life while they last.

> 450 years, according to Florida Department of Environmental Protection (Northwest District), information sourced from the US Environmental Protection Agency Gulf of Mexico Program. Like other plastics, it never truly vanishes: it breaks into smaller and smaller microplastics. The cap lasts even longer on our list: > 500 years.

> 100 years. European Commission, Speech Repository gives a range, and we show its lowest figure. A floating bag looks like a jellyfish, so sea turtles swallow it.

> 600 years, the longest of any plastic item on our list. Lost line keeps catching animals for years, which is why it gets the top wildlife mark (3 of 3) on our scale.

> 10 years (U.S. National Park Service, First State National Historical Park (Junior Ranger Online)). The filter looks like cotton but is a plastic, cellulose acetate, and it leaks toxic chemicals into the water the whole time. It gets the top toxicity mark (3 of 3) on our scale.

> 200 years (Florida Department of Environmental Protection (Northwest District), information sourced from the US Environmental Protection Agency Gulf of Mexico Program). Aluminium leaks little poison, but torn cans and openings can cut or trap small animals.

> 1,000,000 years (U.S. National Park Service, First State National Historical Park (Junior Ranger Online)). Glass is made from minerals and does not poison the water, but it hardly breaks down at all, and broken glass is sharp.

> 50 years (Florida Department of Environmental Protection (Northwest District), information sourced from the US Environmental Protection Agency Gulf of Mexico Program). Foam crumbles into small white beads that birds and fish mistake for food. A foam box lasts > 50 years and a foam buoy > 80 years.

> 450 years, from Ville d'Osny (French municipal government). Disposable masks are made of polypropylene, a plastic, and their ear loops can tangle birds and other animals.

> 450 years (Florida Department of Environmental Protection (Northwest District), information sourced from the US Environmental Protection Agency Gulf of Mexico Program). Disposable diapers contain plastic layers and absorbent gel, so they last for many human lifetimes.

> 200 years (U.S. National Park Service, First State National Historical Park (Junior Ranger Online)). Straws are so light that wind and rain carry them to rivers and the sea, where they break into microplastics.

NOAA Marine Debris Program blog (US National Oceanic and Atmospheric Administration) says balloons can last for years, without a single number, so we write “many years” instead of inventing one. Animals can mistake balloon pieces for food, and ribbons can wrap around them.

Paper goes fast: Newspaper (> 6 weeks), Cardboard box (> 2 weeks), Paper bag (> 1 month). Inks, glue and wax coatings still pollute while it happens.

Natural fibres rot fairly fast: Cloth T-shirt (> 1 month), Wool sock (> 1 year), Wool glove (> 1 year). Clothes made of polyester or nylon are plastic and shed tiny fibres with every wash.

14 of the 31 items on our list last more than 100 years, and 2 of them more than 1,000 years.

On our list: Milk carton, Newspaper, Cloth T-shirt, Paper bag, Cardboard box. Even these can harm animals while they float, and their inks and coatings stay behind.

It means “more than”. When a source gives a range, we show its lowest figure with “>”, so no item looks safer than the source says. Each item's page shows the full range, the source's own words and a link to it.

Usually, yes. Breakdown needs sunlight, warmth and microbes, and the deep sea is dark and cold, so trash that sinks can last longer than the times on most charts. Those times are estimates for typical conditions.

Roughly, but not exactly: fresh water, temperature and sunlight change how fast things break down. Most trash in the sea came down a river first, so keeping rivers clean protects the ocean too.

Breakdown depends on sunlight, temperature, oxygen and microbes, so the same item lasts longer in cold, dark water than on a sunny beach. Most figures come from educational charts, not exact lab measurements. We show the lowest figure each source gives, with a “>” sign, so nothing looks safer than it is.

In the sea, the plastic bag: it lasts > 100 years and scores 8/10 on our scale, while a paper bag breaks down in > 1 month and scores 1/10. Paper bags take more resources to make, though, so the best bag is one you reuse many times.

A plastic bottle lasts > 450 years and breaks into microplastics (score 8/10). A can lasts > 200 years (score 6/10). A glass jar lasts > 1,000,000 years but is not toxic (score 5/10). A refillable bottle beats all three.

Yes. A foam cup lasts > 50 years (score 7/10) and crumbles into beads animals swallow; a milk carton breaks down in > 3 months (score 1/10).

For the sea, yes. A painted ice cream stick lasts > 13 years and a pencil > 13 years, while a plastic fork lasts > 200 years. Wood can still carry paint and glue, but it does not turn into microplastics.

Because the score is more than time. Glass gets 4 of 4 for lasting, but 0 of 3 for toxicity and 1 of 3 for harm to wildlife. A plastic bottle gets 4 for lasting, 2 for toxicity and 2 for wildlife, because it breaks into microplastics that animals swallow.

Yes. A rubber boot lasts > 50 years, and rubber wears into small particles and releases chemicals, so it gets 2 of 3 for toxicity on our scale.

Above all the items animals swallow or get tangled in: Fishing line, Face mask, Balloon. Fishing line and balloon ribbons wrap around fins, flippers and beaks, and turtles mistake plastic bags for jellyfish.

NOAA's Marine Debris Program explains that a floating bag looks like a jellyfish, a favourite food of sea turtles, and is often swallowed before the turtle knows the difference. Plastic cannot be digested: it can block the gut and make an animal feel full while it starves.

It wraps around fins, flippers, wings and beaks and cuts deeper as the animal swims or grows. Fishing line lasts > 600 years, so one lost line can catch animal after animal.

Yes. NOAA Marine Debris Program blog (US National Oceanic and Atmospheric Administration) warns that animals can mistake balloons for food, and that swallowing them can lead to internal injury, starvation and death. Balloon ribbons are strings that can also wrap around animals, and a released balloon always comes down somewhere, often in the sea.

A disposable mask is made of polypropylene, a plastic that lasts > 450 years, and its elastic ear loops can tangle birds and other animals. Cut the loops and put used masks in a closed bin.

Polystyrene foam breaks into small beads very easily. Animals swallow them, and like other plastics they can carry chemicals. On our scale foam gets 2 of 3 for toxicity.

On our scale, Cigarette butt is the only item with the top toxicity mark, because its filter leaks nicotine and heavy metals. 12 more items get 2 of 3, mostly plastics, foam and rubber.

Yes. A study of 159 reefs in the Asia-Pacific found that the chance of disease rose from about 4% to 89% when corals were in contact with plastic (Lamb et al., Science, 2018). Plastic scratches corals, blocks light and can carry germs.

Microplastics have been found in seafood, sea salt and drinking water. Scientists are still studying what they do to human health, but keeping plastic out of the sea is the surest way to keep it off our plates.

Sea turtles, seabirds, seals, whales and fish. They swallow trash they mistake for food or get tangled in lines and nets. On our list, the items with the top wildlife mark are Fishing line, Face mask, Balloon.

Yes. The filter is a plastic (cellulose acetate) that leaks nicotine, arsenic and heavy metals. In a lab study, the leachate of about one smoked butt per litre of water killed half of the test fish within 96 hours (Slaughter et al., Tobacco Control, 2011).

It adds three parts: how long the item lasts (0 to 4), how toxic it is (0 to 3) and how much it harms wildlife (0 to 3), for at most 10. It is the game's own scale for comparing items, not an official index.

Not really. Sunlight and waves break plastic into smaller and smaller pieces called microplastics, and NOAA says plastic may never fully go away. The times for plastic items are estimates of when they fall apart, not of when they are gone.

NOAA's National Ocean Service defines microplastics as plastic pieces less than five millimetres long. They come from bigger trash breaking apart and from things like synthetic fibres, and fish, seabirds and other animals swallow them.

Most of it starts on land: litter, overflowing bins and badly managed dumps, carried by wind, rain and rivers. Ships and fishing add lost nets, lines and buoys.

Not much. The UN Environment Programme's 2015 report on biodegradable plastics found that many need the heat of industrial composting, above 50 °C, which the sea almost never reaches, and that switching to them would not significantly reduce the plastic entering the ocean.

Not a floating island of trash. NOAA describes garbage patches as areas where ocean currents collect debris, mostly tiny pieces of microplastic spread through the water, more like pepper flakes in a soup than something you can skim off.

Hardly. They are too small and spread too widely to filter out, so the real fix is stopping bigger trash before it reaches the sea and breaks apart.

It breaks down in weeks or months, but inks and wax coatings still pollute, and a soggy bag can smother small animals for a while. Paper is better recycled than thrown away.

They rot much faster than plastic, but dyes, paint, glue and wood treatments leach into the water, and loose cloth can snag animals.

Glass does not poison the water, but it never really breaks down: the US National Park Service says a glass jar can take a million years. Broken glass cuts animals and people.

Refuse single-use plastic when you can, carry a bottle and a cloth bag, put litter in a closed bin, never flush cotton swabs or wipes, take fishing line home, and join a beach or river clean-up.

In a closed bin, never the toilet. Flushed swabs and wipes can slip through sewage plants and reach rivers and the sea. Cut the ear loops of masks first.

Take it home, cut it into short pieces and put it in the bin, or use a fishing line recycling bin if your harbour or tackle shop has one. Never leave it on rocks or piers.

Look for a local group or a clean-up day such as the International Coastal Cleanup each September. Wear gloves, leave needles and other dangerous items to the organisers, and count what you find: those counts help scientists.

Yes. Every item you pick up can no longer hurt an animal or break into microplastics. A bottle cap removed today is one less piece of plastic in the sea for > 500 years.

By seeing it and doing something about it: a walk on the beach with an adult, sorting the rubbish at home, and asking where each item goes after the bin.

Carry a reusable bottle, cup and bag; say no to straws and plastic cutlery you do not need; choose products with less packaging; and repair or pass on things instead of throwing them away.

From 13 public sources, mostly government and education bodies: the US EPA Gulf of Mexico Program, NOAA, the US National Park Service, the European Commission, the UK government and others. Each item's page names its source, quotes it and links to it.

Yes. The full table with times, materials, harm scores and sources is on code4ocean.com as JSON and CSV. Each row names and links the original source, so please quote that source when you use a figure.

We add an item only when a public source gives a figure we can quote and link. When we find one, the item joins this guide and the game.

The team behind Save the Fish, a mobile puzzle game from the Code4Ocean studio. We make games, we are not scientists, so every figure links to the public source it comes from.

In Save the Fish you draw bubble walls to stop these items from falling on fish and corals. The game also shows a real fact about one of them, with its source, so players learn while they play.