Professor works to clean up Ohio’s fresh water

Ariel Lev

There is a problem in this country many people have probably seen without even noticing. That problem is acid mine drainage, and this summer, Jenny Baeseman is doing something about it.

Baeseman, an assistant biogeochemistry professor, will spend this summer looking for acid mine drainage sites around Ohio and finding ways to clean them. The actual cleaning will be done by a remediation company that is willing to take on the process. The cleaning of AMD sites around Ohio will improve the environment considerably.

“My job is to clean up infected streams by using organisms that can survive in those conditions,” Baeseman said. “The microorganisms evolve to have more complex membranes. They can regulate pH internally and can create favorable conditions inside themselves.”

Acid mine drainage occurs in areas of heavy construction and, as the name implies, mining. When large quantities of surface rock and precious metals are removed from the ground, iron sulfide (pyrite/fools gold) is exposed to the air. Oxygen and water passing over the pyrite cause it to oxidize or rust. Water filled with AMD is noticeable because of the orange color the water develops.

“This creates free iron and sulfuric acid,” Baeseman said. “The sulfuric acid dissolves other minerals and causes other metals to go into solution. This very acidic solution runs into streams and slowly lowers the pH level. Water then becomes acidic and is toxic to fish, plants, animals and people.”

One of the methods Baeseman will use to try to control stream conditions is bioremediation, which uses biological organisms to repair the environment.

“Bioremediation is used to provide a cost-effective, sound means of cleaning up the environment,” associate geology professor Joseph Ortiz said. “When used properly, bioremediation is a very effective alternative to standard cleanup procedures.”

University professors are looking for ways to stop growth of the bacteria that speeds up the acid mine drainage process.

There are two methods of stopping this growth: adding carbon or adding nitrate.

Adding materials such as sawdust or straw raise the carbon level in the water. More carbon forces microorganisms to grow faster and out-compete the ones that oxidize pyrite, according to Baeseman.

Adding nitrate to infected streams helps control the problem as well.

“Bacteria breathe nitrate not oxygen,” Baeseman said. “During breathing they produce water with alkalinity. This water acts as a buffer and increases the pH in the stream. This stimulates the growth of nitrate-breathing organisms and naturally increases pH levels.”

Once one of these treatment methods has been successfully employed, the water’s orange color goes away and life begins to return to the region.

“The streams won’t be orange, fish will be back, wildlife will have a clean system and AMD will no longer affect our drinking water,” Baeseman said. “Lead, arsenic, zinc, copper and other minerals are very toxic at levels found in our streams. We have a limited source of fresh water and this cleanup allows for us to have more clean water sources.”

Bioremediation is also useful in other disaster situations, such as the Exxon-Valdez oil spill.

“They seeded the area with cultures of bacteria to pick up hard-to-clean waste,” Ortiz said. “Steam cleaning and other conventional methods didn’t help but bioremediation was good for it.”

Bioremediation can be used to fix some of Earth’s other problems as well. Problems such as the world’s excess carbon dioxide can be fixed using a fairly simple form of bioremediation: planting trees.

Planting more trees helps compensate for the abundance of deforestation found around the world. Trees remove some of the carbon dioxide from the air while replacing it with oxygen. However, this method is not as simple as it sounds.

“It’s not enough to plant a tree,” Ortiz said. “You have to plant it in the right place.”

Contact sciences reporter Ariel Lev at [email protected]