What are the types of biodegradable substances?
The term biodegradable is used to describe materials that decompose through the actions of bacteria, fungi, and other living organisms. Temperature and sunlight may also play roles in the decomposition of biodegradable plastics and other substances. If such materials are not biodegradable, they remain in the environment for a long time, and, if these same substances are toxic, they may pollute the soil and water. Some nonbiodegradable pollutants may be capable of causing harm to organisms in the environment. Common, everyday substances that are biodegradable include food refuse, tree leaves, and grass clippings. Many communities now encourage people to compost these materials and use them as humus (an organic-rich material in soil) for gardening. Because plant materials are biodegradable, composting is one way to reduce amounts of solid waste that towns and cities otherwise have to dispose in landfills. In many cases, scientists can come up with biodegradable alternatives to nonbiodegr