Litter

Litter consists of waste products that have been discarded incorrectly, without consent, at an unsuitable location. The waste are objects, often man-made, such as aluminum cans, paper cups, food wrappers, cardboard boxes or plastic bottles, and also include hazardous items such as tires, electrical appliances, electronics, batteries and large industrial containers. Items are sometimes dumped in isolated locations, such as national forests and other public lands.

Litter is a type of human impact on the environment and is a serious environmental problem in many countries. Litter can exist in the environment for long periods of time before decomposition and be transported over large distances into the world's oceans. Litter can negatively affect quality of life.

Cigarette butts are the most littered item in the world, with an estimated 4.5 trillion discarded each year. Estimates of the required time for cigarette butts to break down vary, ranging from 5 to 400 years for complete degradation.

Causes

In addition to intentional littering, almost half of litter on U.S. roadways is now accidental or unintentional litter, usually debris that falls off improperly secured trash, recycling collection vehicles and pickup trucks. Population levels, traffic density and proximity to waste disposal sites are factors known to correlate with higher litter rates.

Illegally dumped hazardous waste may be a response to the costs of dropping materials at designated sites: some of these charge a fee for depositing hazardous material. Lack of access to nearby facilities that accept hazardous waste may deter use. Additionally, ignorance of the laws that regulate the proper disposal of hazardous waste may cause improper disposal.

According to a study by the Dutch organization VROM, 80% of people claim that "everybody leaves a piece of paper, tin or something, on the street behind". Young people from 12 to 24 years cause more litter than the average (Dutch or Belgian) person; only 18% of people who regularly cause litter were 50 years of age or older. However, a 2010 survey of littering in Maine, New Hampshire and Vermont in the United States, placed litterers aged 55 and over at less than 5%. The same observational study estimated that 78% of litterers are male. Litter organizations, such as Keep America Beautiful affiliates, Keep Northern Ireland Beautiful, and the Bay Area Stormwater Management Agencies Association, have focused educational efforts on youth littering.

Negligent or lenient law enforcement contributes to littering behavior. Other causes are inconvenience, entitlement and economic conditions. A survey of dumping in Pennsylvania found that the largest number of illegal dumps were in townships without municipal trash hauling. The same report also cites unavailability of curbside trash and recycling service, shortage of enforcement, and habit as possible causes. The presence of litter invites more littering.

Two-stage process model

The two-stage process model of littering behavior describes the different ways in which people litter. The model was proposed by Chris Sibley and James Liu and differentiates between two types of littering: active and passive.

The theory has implications for understanding the different types of litter reduction interventions that will most effectively reduce littering in a given environment. The theory states that, all things being equal, passive littering will be more resistant to change because of two psychological processes: 1. diffusion of responsibility that increases as the latency between when an individual places litter in the environment and when they vacate the territory, and 2. forgetting, which is also more likely to occur at longer delays between when an individual places litter in the environment and when they vacate the territory.

Life cycle

Litter can remain visible for extended periods of time before it eventually biodegrades, with some items made of condensed glass, styrofoam or plastic possibly remaining in the environment for over a million years.

About 18 percent of litter, usually traveling through stormwater systems, ends up in local streams, rivers, and waterways. Uncollected litter can accrete and flow into streams, local bays and estuaries. Litter in the ocean either washes up on beaches or collects in ocean gyres such as the Great Pacific Garbage Patch. About 80 percent of marine debris comes from land-based sources.

Some litter that is collected can be recycled; however, degraded litter cannot be recycled and eventually degrades to sludge, often toxic. The majority of litter that is collected goes to landfills.

Effects

Litter can have a detrimental impact on humans and the environment in different ways.

Effects on humans

Hazardous materials encapsulated within tires and other items of illegally dumped rubbish can leach into water sources, contaminate the soil and pollute the air.

Tires are the most often dumped hazardous waste. In 2007 the United States generated 262 million scrap tires. Thirty-eight states have laws that ban whole tires being deposited in landfills. Many of these discarded tires end up illegally dumped on public lands. Tires can become a breeding ground for insect vectors which can transmit disease to humans. Mosquitoes, which breed in stagnant water, can transmit West Nile virus and malaria. Rodents nest in accumulated tires and can transmit diseases such as Hantavirus.

When tires are burned, they can smolder for long periods of time, emitting hundreds of chemical compounds that pollute the air causing respiratory illnesses. Additionally the residue left behind can harm the soil and leach into groundwater.

Visual pollution is a major effect of litter.

Open containers such as paper cups, cardboard food packets, plastic drink bottles and aluminum drinks cans get filled up with rainwater, providing breeding locations for mosquitoes. In addition, a spark or a lightning flash can start a fire if it strikes litter such as a paper bag or cardboard box.

Litter can be hazardous to health. Debris falling from vehicles is an increasing cause of automobile accidents. Discarded dangerous goods, chemicals, tires, sharps waste and pathogens resulting from litter can cause accidental harm to humans.

Litter also carries substantial cost to the economy. Cleaning up litter in the US costs hundreds of dollars per ton, about ten times more than the cost of trash disposal, with a cost totaling about $11 billion per year.

Effects on wildlife

Animals may get trapped or poisoned with litter in their habitats. Cigarette butts and filters are a threat to wildlife and have been found in the stomachs of fish, birds and whales, who have mistaken them for food. Also, animals can get trapped in the rubbish and be in serious discomfort. For example, the plastic used to hold beverage cans together can get wrapped around animals' necks and cause them to suffocate as they grow. Other instances where animals could be harmed by litter include broken glass lacerating the paws of dogs, cats, and other small mammals.

Other effects

Organic litter in large amounts can cause water pollution and lead to algal blooms. Cigarettes could also start fires if they are not put out and then discarded in the environment.

High-rise littering

High-rise littering occurs when people litter from the windows of high-rise buildings. Apart from the general harms of littering, this also endangers people below, risking injury or death.

Extent

Litter is an environmental concern in many countries around the world. While countries in the developing world lack the resources to deal with the issue, consumer-based economies in the western world are capable of generating larger quantities of litter per capita due to a higher consumption of disposable products.

Branded litter

A number of credible studies have shown that fast food packaging is one of the most common forms of litter, while McDonald's is the most common brand of litter, despite having messages to dispose of it properly, such as the Ronald McDonald "tidy man" marking. According to Keep Britain Tidy in 2013, Cadbury chocolate wrappers, Walkers crisp packets and Coca-Cola cans were the three top brands that were the most common pieces of rubbish found in UK streets.

Solutions

Cleanup

Volunteers, sometimes alone or coordinated through organizations, pick up litter and dispose of it. Clean up events may be organized in which participants will sometimes comb an area in a line to ensure that no litter is missed. Organizations may promote litter cleanup events and may also have separate media campaigns to prevent littering. In North America, Adopt a Highway programs are popular, in which companies and organizations commit to cleaning stretches of road. Keep America Beautiful has held litter cleanups called the Great America Cleanup since 1998 in over 20,000 communities nationwide. Earth Day cleanups have been held globally since 1970.

Litter traps

Litter traps can be used to capture litter as it exits stormwater drains into waterways. However, litter traps are only effective for large or floating items of litter and must be maintained. A recent watershed litter survey showed a difference in the composition of street litter and stormwater litter.