A harmful chemical produced by oil companies and slaughterhouses, known to cause cancer and birth defects, made up a vast majority of chemical pollution in 2020.
A recent study found that approximately 94.5 million pounds of nitrates were released into the Mississippi River alone in 2020, making up more than half of all released chemicals nationwide. These nitrates were the most abundant toxic substances found in U.S. waterways, primarily from industries such as petroleum refineries and meat and poultry processing plants. One hundred and seventy-five million pounds of nitrates alone were released by industries, comprising more than 91% of all toxic chemicals released by weight in the United States. These nitrates are primary sources of plant nutrients, but they are not as beneficial as they seem.
While in controlled amounts, nitrates are healthy for plants and commonly used in fertilizers, excessive amounts lead to rapid growth and accumulation of algae in marine or freshwater environments. These algae blooms can grow massive, dense “blankets” over bodies of water, blocking out sunlight. At the same time, as the amount of algae increases and dies, the decomposers in the water use more oxygen to break down the dead algae, leading to hypoxic waters, and stripping other aquatic life of oxygen.
For humans, nitrate is a common groundwater contaminant, polluting 10% of wells in Wisconsin. Prolonged exposure can result in birth defects in infants, and colon, kidney, and stomach cancers in adults.
There are policies to limit these pollutants, such as the Clean Water Act, which requires not just U.S. states, but also territories and tribal governments, to create standards based on certain purposes such as drinking or recreation. Failure to comply with these standards results in a restoration plan, limiting daily released pollutants.
Although this law has increased fishable waters, many industries are exempt or find loopholes to discharge their chemicals. For example, establishments with fewer than ten employees do not need to make reports. There are also specific substances, as well as runoff from farms and animal-feeding plants, that do not need to be included in reports.
In the future, the Environmental Protection Agency plans to update pollution standards that would hold previously exempt businesses and industries, such as meat and poultry processing plants and power plants, accountable for releasing chemicals.