Potential Health Effects of Oil Contamination in Nigeria Becomes Focus of Public Health Forum.
Vast oil deposits that enrich Nigeria are both a blessing and a curse for its people, who have endured decades of water, soil and air contamination as the unwanted byproducts of oil wealth.
“I’ve worked on contaminated sites for more than 20 years and I’ve never seen anything on the scale that I saw in Nigeria,” said Donna Vorhees, an adjunct assistant professor of environmental health at BUSPH. “They’re not just exposed – these people are actually living in petroleum.”
At a March 7 public health forum, Vorhees delivered a presentation on her work assessing health risks in the oil-rich Ogoniland region of Nigeria. She was part of a multinational United Nations Environmental Programme (UNEP) team that examined more than 200 locations and conducted detailed soil and groundwater contamination investigations at 69 sites. More than 4,000 samples were analyzed, including water from 142 groundwater-monitoring wells and soil from 780 boreholes.
Vorhees explained that after more than 50 years of oil processing and widespread contamination, Royal Dutch Shell was forced out of the area in the early 1990s by local protests. She showed images of barren mangrove swamps, the dead root systems caked with oil, and aerial photos of green wetlands turned black with oil.
While processing in Ogoniland may have slowed, Vorhees said a host of lingering problems contribute to ongoing contamination, including poor waste disposal, pipeline fires, illegal refining, failed pipes and damaged wellheads.
The team didn’t have to venture far to find sources of contamination. One air monitoring site was set up on the banks of an oil-blackened waterway that reeked of volatile compounds strong enough to sting the researchers’ eyes after a few minutes. Groundwater samples were taken from the faucet of a bored well whose water felt greasy and emitted enough of a benzene stench to send Vorhees reeling.
“After cupping my hand and smelling it, and just feeling almost knocked backward by the fumes, I looked over to see a man calmly brushing his teeth with it,” Vorhees said. She tried to get local environmental officials to close the well and start immediate remediation, but they didn’t seem to understand the urgency, Vorhees said. “That’s when I realized that for the local people, especially the young ones, this is all they’ve ever known.”
Water samples from that well later showed benzene levels of 9,000 micrograms per liter. The US drinking water standard is 5 mcg/l.
In some cases, inadequate remediation just shifted the problem from one potential harm to another. A common method of soil remediation is to fertilize the soil and bulldoze it into windrows to encourage bacterial action. This works adequately on soil over time, Vorhees said, but can cause greater ground water contamination during the rainy season.
Not all hazards were oil-related. The UNEP team was also warned that the safety of the region was in flux, in part due to long-standing resentment of the oil company, and to possibly expect high crime, kidnapping attempts, and poor aviation security. Typically the team went into the field in two large SUVs with UN markings and four police officers. The security measures limited the amount of time the team was able to spend in the field collecting samples. “We couldn’t leave equipment out overnight.”
The air-quality sample design also had to account for possible sources of pollution that were not directly related to the oil spills, such traffic, indoor and outdoor cooking fires, and the practice of tapping into pipelines to illegally refine stolen crude oil.
Data entry and SAS analysis of sample results were performed by BUSPH alums Whitney Cowell, Jiayang Chien, and Joe King, and Harvard SPH post-doctoral student Zhao Dong.
Part of the challenge was collecting health records, in number and enough detail, to assess the adverse health effects of oil exposure — a necessary component of tracking impact. “We don’t really know the chronic effects of exposure to crude oil over time,” Vorhees explained.
Despite visits to multiple regional health centers, the team wasn’t able to gather the level of data needed to link exposure and adverse health effects. “But I don’t know how you can drink water with that high a level of benzene, that smells so strongly as it does, without some effects,” Vorhees said.
In assessing the limitations of this study, Vorhees and the team proposed a new study that would set a baseline for health data to enable more accurate longitudinal data collection. In this way, Vorhees said, “What we saw in Nigeria could possibly help us understand what’s happening in other areas affected by oil spills.”
Submitted by Michael Saunders msaunder@bu.edu