Scientific Research

Dominic Joel Ombati

My PhD research in environmental geology is about Fate and Transport of  Lead (Pb) along the Arid Section of Route 66, San Bernardino County, California. Fate and transport research project can be defined as the study of how chemicals degrade and where they travel in the environment when they are released intentionally or unintentionally. Transport is how chemicals move through the air, water and soil and fate is how chemicals change in the environment.

In my study area, anthropogenic lead (Pb) along Route 66 is mainly from leaded gasoline and it was deposited during the leaded gasoline era. Spatial distribution and surface transport mechanism of  lead (Pb) along the arid section of Route 66 in San Bernardino County, California is my first PhD research project. Lead (Pb) chemical fractionation along Route 66 in San Bernardino County, California is my second PhD research project. My third PhD research project is to develop a digital educational outreach program on lead (Pb) poisoning with a focus on populations at a higher risk of lead (Pb) poisoning in sub-Saharan Africa where the largest known outbreak of  lead (Pb) poisoning occurred.

Scientific Research on Lead Poisoning.

   THE LARGEST KNOWN OUTBREAK OF LEAD POISONING.

The worst documented case of childhood lead (Pb) poisoning outbreak occurred in Zamfara State, Northern, Nigeria where about 400 children died and thousands more were disabled in the artisanal gold mining villages (Dooyema et al., 2012; Plumlee et al., 2013). The outbreak was discovered in 2010. Gold ores with lead (Pb) rich veins were mined manually and were transported in household bags to the villages for processing (Plumlee et al., 2013). First stage of ore processing involved breaking down the lead (Pb) rich gold ores manually using hammers followed by manual grinding of the broken ore fragments using household mortars and pestles or mechanical grinding by gasoline-powered flour mills that also were used to grind grains for the villagers (Plumlee et al., 2013). The grinding of lead (Pb) rich gold ores generated large amount of easily inhalable lead (Pb) rich dust.

To concentrate gold particles, ground lead (Pb) rich gold ores were washed with a shower of water at the village water sources and then the concentrates were combined with liquid mercury manually in household cooking pots to form a gold-mercury amalgam which allowed minute pieces of  gold to be extracted when mercury was vaporized (Plumlee et al., 2013). The villagers were significantly exposed to mercury which is also dangerous to human health. United States Environmental Protection Agency (EPA) has mercury free gold mining techniques for artisanal and small scale gold mining (ASGM). Older children worked with their family members at the processing and sometimes  processing and storage of lead (Pb) rich gold ores occurred where children played and lived (Plumlee et al., 2013). 

Researchers found that surviving children < 5 years old had Blood Lead Levels (BLL) up to 370 µg/dL (Dooyema et al., 2012). CDC recommends Blood Lead Level (BLL) be < 3.5 µg/dL. Worse off, soils contaminated by washing wastes were used to make bricks for building houses in the villages (Plumlee et al., 2013). There was high lead (Pb) exposure at all stages of gold mining and processing in these artisanal gold mining villages and that is how the worst documented lead (Pb) poisoning disaster occurred. Several agencies responded to this outbreak and the situation has improved but a lot more has to be done to avoid future outbreaks. This digital educational outreach program has made deliberate online efforts to target the affected artisanal gold mining villages in Zamfara State, Nigeria with links to credible digital educational materials on lead (Pb) poisoning.