Thiaroye Sur Mer, Dakar, Senegal
Thiaroye Sur Mer (TSM) has been the site of Used Lead Acid Battery recovery since the 1970s. Mean blood lead levels in children were >100 µg/dL and individual levels were >350 µg/dL. Eighteen (18) children died as a direct result of lead exposures in 2007-08. Multiple groups recovered lead from batteries to manufacture weights for local fishermen. Several thousand tons of discarded battery sludge accumulated in the area over three decades. In 2007, dramatic increases in lead prices stimulated East Indian traders to purchase the lead oxide sludge. To minimize shipping costs, 200 local women were employed to sift out beach sand that had accumulated with the sludge. The process involved transporting, drying, sifting and bagging the lead dust. Bags of lead product were stored in homes prior to sale. Many mothers brought their infants and toddlers with them to work.
Limited emergency remediation activities were undertaken in April and May of 2008. 300 tons of lead were removed from local homes. The World Health Organization (WHO) tested siblings of the deceased children and forty-one children were subsequently hospitalized and placed in foster care. Massive flooding of the area during the rainy season delayed further action. After the flood subsided, TIFO collaborated with other partners to conduct extensive sampling and interviews of the TSM population.
A health response and remediation strategy were implemented in April 2009. The strategy included establishment of sentinel homes in the community where intensive interviews and sampling were conducted to determine the extent and severity of continuing exposures and to identify active lead exposure pathways. These homes and resident children were monitored to assess the effectiveness of the cleanup.
Blood Lead and Environmental Testing
TIFO assisted the Senegalese Ministry of Health in developing and implementing a blood lead monitoring and follow-up protocol. A total of 97 individuals from 10 homes, including 68 children and 29 mothers, were tested in March 2009, one year following the epidemic. Thirty children <10 years of age had blood lead levels >70 µg/dL. Of 19 children age 18 months to 4 years, 15 had blood lead levels >70 µg/dL. Of the total population, an estimated 250 to 1500 children were poisoned.
Soil concentrations were extremely high throughout the community. The final cleanup plan estimated 4000 m³ of waste >10% lead, 3000 m³ of 1-10% lead, and 1300 m³ of 0.1-1% lead required excavation.
Severe lead contamination of house dust was observed within homes. Average floor lead loadings were 44,000 µg/m², exceeding the U.S. cleanup criteria by a factor of 100. Interior house dust lead levels ranged as high as 27,000 mg/kg concentration (379,000 µg/m² lead loading).
The first phase of the cleanup commenced in June 2009 and was completed in 2010. More than 1100 m³ of contaminated soils were removed from residential lots and streets. About half of this waste was classified as Principal Threat Material (>10% lead) and the remainder ranged from 1-10% lead.
In total, more than fifty local workers were hired and employed in the soil removal. Some of the mothers on the cleanup crews had lost children in the epidemic. Two teams of six local villagers were trained to conduct the interior decontamination and were employed for five months for the initial cleaning.