Pineapple Farming Practice Threatens Human Health in Ghana

April 1, 2006

In the tropical West African nation of Ghana, intense farming practices combined with characteristics of the local geology are making for a dangerous mix, reports Associate Professor of Civil and Environmental Engineering Fred Boadu. Fertilizers and pesticides used to boost the yield of pineapples grown in the country’s thin soils are trickling down through fractured bedrock directly into the water supply below.

The new findings might lead to methods to identify alternative locations for safer drinking water in the village of Nsawam, by avoiding areas with high-intensity directional rock fractures, Boadu said. Pineapples serve as the main source of income for locals in the agricultural community.

The NSF-funded study highlights an important link between geology, engineering and human health, Boadu said.

“While the subsurface rock fractures provide the needed groundwater yield, they also serve as conduits for contamination,” Boadu said.

The findings were an unexpected result of efforts to map the characteristics of subsurface fractures using non-invasive geophysical methods based on electricity, Boadu said. The study -- the first of its kind in Ghana – appeared in Geophysics in September 2005.

Boadu’s team found that nitrates from fertilizer are almost immediately pumped back up through boreholes on which people in the agricultural village depend for water. The group found nitrate levels four times higher than the concentration deemed safe for human consumption in samples taken from the village water pumps.

“Most of the groundwater wells are contaminated with nitrates from fertilizers, at highly elevated levels that are posing serious risk to human health, especially in women and children,” Boadu said. “Nitrates have been linked to stomach and bladder cancers. They can also lead to birth defects.”

The findings of nitrate levels raise questions about possible exposures to pesticides, including the highly toxic DDT used by the locals, Boadu said. His group will investigate further by testing for other elements, such as arsenic, in the ground water.