Benjamin Bostick, an assistant professor of earth sciences, conducted research at Coakley Landfill in North Hampton, N.H. with four other Dartmouth faculty members to examine how organic compounds in landfills cause arsenic to seep out of the soil and into drinking water. Although the garbage in a landfill may not contain arsenic, there are iron oxides in the soil that do. When these oxides react with microbes in the garbage, arsenic is released into groundwater.
"The growth of microbes can cause things to change form," Bostick said. "Soil has a lot of arsenic naturally, but the microbes can cause the arsenic to form a solution in water."
The Environmental Protection Agency designated the Coakley landfill as an EPA Superfund Site in 1986 because of its hazardous waste content. The site uses Monitored Natural Attenuation, which relies on microbial degradation to reduce dangerous compounds such as benzene, but in turn also releases arsenic.
When water flows through the landfill, arsenic can become incorporated into drinking water. Over a long period of time, this can cause serious health problems, according to the EPA website.
"At typical contaminant concentrations, problems are generally long-term," Bostick said. "Drinking arsenic-containing water for a long time can cause various sorts of cancer."
More acute concentrations of arsenic can cause non-cancerous effects such as vomiting, diarrhea, numbness, partial paralysis and blindness.
Although microbial degradation is detrimental in places where water flows through the landfill, it is useful when the water is contained and does not contaminate drinking water, Bostick said.
The problem of arsenic contamination is a worldwide issue, particularly in Bangladesh.
"Sediment coming from the Himalayas has the potential to release a lot of arsenic," Xiahong Feng, a coauthor on the study, said.
As a result, many countries in the surrounding area are at risk for having high levels of arsenic in drinking water.
Bostick and his colleagues continue to oversee arsenic studies in New Hampshire and to study the process by which arsenic contamination occurs.
