Effects of Toxic Waste on Animals

Various manufacturing processes produce waste that can be harmful to the environment. While these industrial processes are important in creating the consumer goods and amenities we value in the modern world, if the waste they generate is improperly handled it can constitute a threat to animals or their habitats and thereby cause environmental damage. The Environmental Protection Agency classifies substances that ignite easily, corrode metals, react readily or are toxic as hazardous waste.

Mutagens, Carcinogens and Teratogens

• Mutagens are chemicals that cause mutations by damaging DNA in animal cells. Since some mutations can cause cancer, mutagens are typically carcinogens as well. Animals, like humans, can develop cancer and are vulnerable to mutagenic chemicals and compounds, although some compounds are more likely to cause cancer in certain species than in others, depending on how the compound is metabolized and how it interacts with other substances. Some pollutants are also teratogens, meaning that they can cause birth defects in unborn animal fetuses.

Endocrine Disruptors

• Endocrine disruptors are chemicals that interfere with the activity of the endocrine system, the glands in the body that secrete chemical messengers called hormones. If a chemical is similar in structure to a hormone, it may mimic the activity of the hormone in the bloodstream; alternatively, some endocrine disruptors block the activity of the hormone instead. As noted in a 2009 article in Discovery News, various studies have found an increasing number of hermaphroditic fish and amphibians in recent years; some researchers believe these changes are due to the effect of endocrine-disrupting chemicals released into the environment.

Chronic and Acute Toxicity

• Chemicals such as mutagens have chronic toxicity, meaning that they damage an animal's health through prolonged exposure over a long period of time. Other chemicals have acute toxicity, meaning that they kill or seriously damage animals through short-term exposure. Cyanide compounds, such as hydrogen cyanide and potassium cyanide, are an especially infamous example; the cyanide ions released by these compounds when they dissociate in water block a vital process that cells use to make energy and rapidly cause death. According to BBC News, a cyanide spill in the River Trent in 2009 caused the death of thousands of fish.

Bioaccumulation

• Some toxic substances are rapidly broken down or excreted from the body. Some compounds, however, and especially those that are fat-soluble, may remain in the body for a longer period of time. When organisms near the bottom of the food chain ingest these compounds, they can become stored in the organism's tissues; these toxic substances may then in turn be transferred to predators and make their way up the food chain. Organisms at the top of the food chain may end up with a much higher concentration of these toxins. This process is called bioaccumulation.