Most environmental litter is made of plastic. In oceans, plastic accounts for at least 85% of all waste, and it dominates on land too. But litter is far from a single material. It’s a mix of synthetic polymers, metals, glass, paper, plant-based plastics, rubber, and increasingly, electronic components from disposable devices like vapes. Each material breaks down differently and carries its own chemical footprint.
Plastic: The Dominant Material
Plastic litter isn’t one substance. It’s a family of synthetic polymers, each with different properties and sources. The largest contributor is polyethylene, the flexible plastic used in grocery bags, food wrap, and squeeze bottles. An estimated 3.2 million metric tons of polyethylene enter the environment every year. Next comes polyethylene terephthalate (PET), the rigid, clear plastic in drink bottles and food containers, at 1.6 million metric tons annually. Polypropylene, found in bottle caps, yogurt containers, and food packaging, adds another 1.3 million metric tons.
Polystyrene, the material in foam takeout containers and disposable cups, contributes roughly 500,000 metric tons per year. Polyvinyl chloride, used in construction materials and some packaging, adds about 300,000 metric tons. Plastic fibers, which shed from synthetic clothing and textiles, account for a surprisingly large 2.4 million metric tons entering the environment annually. Rubber, mostly from tire wear, also counts as a polymer pollutant, and roughly 59% of environmental rubber accumulates in soil rather than waterways.
Where these plastics end up depends on their density. Lightweight plastics like polyethylene float and spread across water surfaces. Heavier plastics like PET and PVC sink to the bottom of rivers, lakes, and oceans, accumulating in sediment along with synthetic fibers.
Cigarette Filters: A Hidden Plastic
Cigarette butts consistently rank as the single most collected litter item worldwide, and most people don’t realize they’re plastic. The filter in nearly every commercial cigarette is made from cellulose acetate, a plant-based plastic derived from wood pulp but chemically modified to behave like a synthetic polymer. Each filter contains between 12,000 and 15,000 individual cellulose acetate strands packed tightly together.
The manufacturing process adds plasticizers to make the filter flexible and help it bond to the paper tube. Some filters also contain activated charcoal. Once smoked, these filters absorb tar, nicotine, and heavy metals from the tobacco. When discarded, they slowly release those trapped chemicals into soil and water as the cellulose acetate breaks apart over months or years. Unlike pure cellulose (think cotton or paper), cellulose acetate resists natural decomposition because of its chemical modifications.
Chemicals That Leach From Litter
The materials in litter are only part of the story. Plastics contain a range of chemical additives designed to make them flexible, flame-resistant, colorful, or durable. These additives don’t stay locked inside. Research published in Environmental Science & Technology found that both new and environmentally weathered plastic items leach persistent, mobile, and toxic compounds when exposed to water.
The chemical classes found in plastic litter include phthalates (used as softeners), organophosphate esters (used as flame retardants), and per- and polyfluoroalkyl substances, commonly known as “forever chemicals.” Flame retardants were among the most frequently detected compounds across tested items. Children’s toys were found to leach several compounds containing nitro groups, which are a concern because of their potential toxicity. Food-contact plastics, like containers and wraps, also released measurable levels of chemicals classified as persistent and mobile in the environment.
Metal and Glass Litter
Aluminum cans and glass bottles make up a smaller share of total litter than plastic, but they persist for centuries in the environment. An aluminum can takes an estimated 200 years to break down. Glass is essentially permanent, fragmenting into smaller shards but never truly decomposing.
Aluminum litter is mostly beverage cans made from an alloy of aluminum, manganese, and magnesium, coated with a thin polymer lining on the inside to prevent the drink from reacting with the metal. Glass bottles are made from silica sand, soda ash, and limestone, melted together at extremely high temperatures. Both materials are infinitely recyclable without losing quality, which makes their presence as litter particularly wasteful. A University of Southampton study found that glass bottles carry a heavier overall environmental footprint than plastic or aluminum containers across their full lifecycle, from raw material extraction through disposal.
Disposable Vapes: A New Category
One of the fastest-growing types of litter combines plastic, metal, and hazardous chemicals in a single small device. Disposable vapes contain a lithium battery, electrical circuitry with heavy metals, a plastic outer shell, and residual liquid carrying nicotine and flavoring chemicals. The U.S. Environmental Protection Agency classifies nicotine as an acute hazardous waste.
When these devices end up as litter, the lithium batteries can break down and leach toxic compounds into surrounding soil and water. The e-liquid inside contains heavy metals and lead alongside the flavoring chemicals. The plastic housing doesn’t decompose. Unlike a plastic bottle or aluminum can, a discarded vape is simultaneously plastic waste, electronic waste, and hazardous chemical waste, which is part of why they’re so difficult to manage in waste systems designed to handle one material type at a time.
Paper and Organic Litter
Paper products, including fast-food wrappers, receipts, napkins, and cardboard, make up a visible portion of street-level litter. Plain paper breaks down relatively quickly, often within weeks in wet conditions. But most paper litter isn’t plain. Fast-food wrappers and cups are coated with thin layers of polyethylene or wax to make them grease- and water-resistant, which dramatically slows decomposition and introduces plastic into what looks like a paper product.
Food waste, yard trimmings, and wood also appear in litter surveys, though they decompose faster than any manufactured material. Their main environmental concern is attracting pests and contributing to nutrient runoff into waterways rather than long-term persistence.
Why Material Composition Matters
Knowing what litter is made of changes how you think about its impact. A plastic bag and a newspaper tossed on the same sidewalk look equally messy, but their environmental timelines are completely different. The newspaper will be gone in weeks. The bag will fragment into microplastics over decades, releasing chemical additives along the way, and those fragments will eventually reach waterways where they join the 85% of marine debris that is plastic.
The trend is also shifting. Litter is becoming more chemically complex as single-use electronics, coated paper products, and multi-material packaging replace simpler waste. A disposable coffee cup might contain paper, polyethylene, and ink. A discarded vape contains plastic, lithium, nickel, copper, lead, and nicotine. Each layer of material complexity makes the litter harder to break down naturally and harder to recycle if it’s ever collected.