Case Studies in Groundwater Pollution

What would you do if you found out your school was sitting on top of a toxic waste dump? What would you do if you found out that the water you drink contains arsenic? Read through the following case studies to learn how some people dealt with groundwater pollution.

Case Study: Love Canal, New York

a woman from the Love Canal site holding a sign that says "We've got better things to do than sit around and be contaminated."

In the 1970s, an entire community near Niagara Falls found out that their homes and schools were built over an abandoned waste dump. It was leaking poisonous chemicals into the groundwater beneath it. The chemicals were left over as byproducts of a dry cleaning industry that had once operated there. The leaking waste lead to increased sickness, birth defects, miscarriages, and perhaps even cancer. The residents had to be evacuated from their homes. The event became known as the Love Canal disaster, named after the neighborhood in which it happened. It was one of the worst environmental disasters in our nation’s history.

Love Canal Questions

Over-pumping is not the only problem associated with groundwater use. Based on this case study, what problem is associated with burying toxic wastes underground?

Any chemical substance applied to or buried in the ground can be a source of groundwater pollution. We often use burial as a means of getting rid of unwanted wastes and chemical byproducts. The buried toxic substances move down through the soil and enter groundwater, just like regular precipitation water.

What effect can contaminated groundwater have on humans?

Because groundwater is a source of drinking water, using contaminated groundwater can pose serious health threats to humans.

Why did the people of Love Canal have to be removed from their homes?

The chemicals could not just be removed. Because groundwater pollutants can enter the small pore spaces in rocks and soils, they are difficult and costly to remove. Furthermore, they can stay in the groundwater for hundreds or thousands of years, because groundwater has little capacity to cleanse itself. That is why the people of Love Canal had to be moved somewhere else.

Case Study: The Ganges Plain

Map showing U.S. locations of arsenic contaminated well water

Another devastating story comes from the Ganges Plain area of northern India and Bangladesh. This area has severe groundwater contamination by naturally occurring arsenic. Arsenic is a carcinogen linked to several types of cancer. Many people in the area have died from drinking the arsenic-contaminated groundwater that was pumped up from wells. As organic matter in the aquifer sediment decays, it generates oxygen-free (anaerobic) conditions. Removing oxygen from the aquifer encourages the dissolution of minerals that contain arsenic. Once arsenic is dissolved, it becomes a very serious threat. Recent deeper wells in the Ganges Plain create even more access to high levels of arsenic.

This problem also occurs in other parts of the world, including the U.S. The U.S. Environmental Protection Agency estimates that as many as 7% of U.S. wells may contain unsafe levels of arsenic. Small, under-the-sink filter systems are available for removing arsenic from well water that people drink.

The Ganges Plain Questions

How did human activity make the problem of arsenic contamination worse?

People dug deeper and deeper wells to get more water. This meant that the arsenic, which is normally too deep to access, was brought up in drinking water.

How could problems like this be avoided?

Careful environmental testing is necessary before groundwater supplies can be allowed for use as drinking water.

Health Threats in Groundwater

Because groundwater is consumed as a source of drinking water, using contaminated groundwater can pose serious health threats to humans. The people in Love Canal became sick, experienced higher rates of cancer, and had children born with numerous birth defects. And the people who drink arsenic-contaminated groundwater in India have developed cancer and become sick. Any substance that is known to cause cancer is called a carcinogen. A substance that causes birth defects is called a teratogen, and a substance that causes genetic damage to a person’s DNA is called a mutagen. All three of these substances, carcinogens, teratogens, and mutagens, are carefully regulated by the U.S. government so that they, hopefully, stay out of groundwater supplies.