on groundwater supplies as a primary source of drinking water, as 97% of the world’s freshwater supplies are in the form of groundwater resources1. As clean freshwater becomes increasingly rare in our world of constrained natural resources, we will need to work especially hard on preventing the pollution of our freshwater resources, especially groundwater supplies.
The following are many of the common sources of groundwater pollution in our world today.
If a septic system is not properly constructed, located or maintained, it can leak pollutants such as bacteria, viruses, and household chemicals, such as paint thinners, into groundwater supplies.
Small Disposal Pits
These are small pits that are used for the dumping and burning of wastes. Groundwater pollution can occur when chemicals, oil, pesticides, and other hazardous pollutants are improperly disposed of in these pits.
House and Garden Chemicals
Groundwater contamination can occur when house and garden chemicals are improperly stored or disposed of in backyards, ditches, septic systems, and overgrown ditches.
De-icing Road Salts
High levels of chloride from excessive use of de-icing road salts can contaminate local waterways and groundwater due to runoff from salt storage piles and highways. This excessive chloride in the water table is harmful for both the environment and for human health, and it can also contaminate local well water supplies.
Landfills contain many different wastes that can be harmful to the environment, such as car battery acid, paint, and household cleaner. Typically, landfills have a protective lining layer at the bottom that will prevent these wastes from leaking. However, if there is no protective lining present, or if the lining has a crack, these wastes can leak onto the ground below the landfill and can pollute local groundwater supplies.
Storage tanks can hold a variety of potentially polluting liquid chemicals, such as gasoline or oil, and can be located either above or below ground. Over time, as these storage tanks age, they can corrode, crack, and develop leaks. This can eventually lead to the leaking of these chemicals and potential groundwater contamination. Such leaks can also occur if the tanks are improperly installed or poorly maintained.
Fertilizers and Pesticides
Agricultural fertilizers can contaminate groundwater supplies due to over fertilization and the application of the fertilizers at non-optimal times, leading to high levels of nitrates in groundwater resources. Proper planning for the right amount of fertilizer at the right time can significantly reduce the pollution of groundwater from these sources.
Pesticides can be a similar groundwater pollution problem when their use is excessive or applied at non-optimal times. They are sometimes stored improperly, resulting in leaks. These chemicals can leach through the soil and negatively impact animals that drink from pesticide contaminated wells, plants that are watered with contaminated well water, and can also negatively impact aquatic life.
Hazardous materials can become pollutants due to their improper storage, handling, use, disposal, spills, and leaks. If a leak or spill does occur, these chemicals can filter down through the soil and can then pollute local groundwater resources.
Intensive animal agriculture can lead to the contamination of groundwater supplies when there are too many animals in a given space, when there is poor drainage of the lot, or when the lot is not cleaned regularly or as necessary. This can lead to high bacteria and nitrate levels in local groundwater resources.
Many different chemicals from urban areas can make their way into groundwater supplies through runoff, such as household and industrial chemicals, metals, nitrates, and oil.
The disposal of contaminated wastewater from hydraulic fracturing (“fracking”) wells produced during through the production of natural gas in underground shale can put local water bodies and groundwater resources at risk of pollution. Pollutants of concern include high levels of salts and radioactive materials such as uranium, radium, and radon, which pose both environmental and health risks2.