Science Corner: Landfill Dangers And Alternatives

A bulldozer rides over a waste pile at a landfill, moving and compacting the garbage before it is eventually covered over.
A bulldozer rides over a waste pile at a landfill, moving and compacting garbage before it is covered. Photo by Alan Levine via

By Shelby Theisen, Development Coordinator

Manatees face many challenges in the wild—from harassment to boat strikes to cold stress—but they may face additional threats from an unlikely source: landfills. Landfills become part of the complex web of issues manatees encounter due to the impact that current and future pollution will have on their habitat. Landfills are a source of air and plastic pollution as well as water contamination, which all have adverse effects on manatees.

  • Air Pollution: Landfills produce multiple greenhouse gases (GHG), including methane and carbon dioxide. Carbon dioxide (CO2) persists in the atmosphere for centuries once it is released. On the other hand, methane (CH4) remains in the atmosphere for around a decade, but it is 25 times more efficient at trapping heat in the atmosphere. In the United States, landfills are the third-largest source of human-related methane production. Recent studies have suggested that three of the top-ten methane-emitting landfills are in Florida, according to the U.S. Environmental Protection Agency (EPA). Methane is produced when organic material is broken down anaerobically, meaning without oxygen. Once the waste at a landfill is covered by turf, soil, or other material, it is essentially sealed, depriving the underground waste of oxygen and promoting the growth of methane-producing anaerobic bacteria. This landfill process is often referred to as dry tomb landfilling. Some landfills have systems to collect the methane produced and use it as fuel; however, there is a lot of uncertainty surrounding how much is actually being prevented from entering the atmosphere with this process.
  • Plastic Pollution: Mismanaged waste like plastics can end up in our waterways and pose serious health risks to manatees if ingested. Plastic pollution can also occur as a result of landfills when microplastics leach into our soil and groundwater.
  • Groundwater Contamination: Groundwater contamination occurs at landfills when rainwater comes into contact with waste and leaches potentially harmful chemicals into the soil and groundwater below. There are requirements and regulations put in place to prevent this; however, the risk is always present, and mistakes or even intentional disregard can undermine those regulations.
  • Small-Scale Composting as a Solution: According to the EPA, in 2018, nearly 300 million tons of waste was generated in the U.S. Out of that 300 million, 25 million tons of municipal solid waste was recovered—including paper and cardboard, food waste, and yard waste—through composting. Still, much of the waste currently taking up space in our landfills—some estimates as high as 50%—is organic material that could have been composted.

Composting is the process of breaking down waste aerobically (in an oxygen-rich environment). Composting is a way to create an ideal environment for organic materials to break down efficiently and with less pollution, as they would naturally. Compost is the product of organic materials breaking down. Small-scale composting can help communities keep their waste out of landfills while bringing nutrients back into the soil without producing the dangerous GHG methane.

Moving away from dry tomb landfills as the traditional approach to managing municipal solid waste and focusing on waste reduction and recovery may help reduce air pollution from methane emissions and the risk of soil and groundwater contamination. All of these contribute to the degradation of our environment, including vulnerable manatee habitat.

If you are interested in learning more about composting, visit You can also reduce the amount of waste you send to landfills by learning more about proper recycling practices and ways to reduce food waste at home. If you have limited time and space, there may be a local, small-scale composting program in your community.

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