In ternationa l Scholars Journa ls African Journal of Environmental Economics and Management ISSN 2375-0707 Vol. 7 (1), pp. 001-010, January, 2019. Available online at www.internationalscholarsjournals.org © International Scholars Journals Author(s) retain the copyright of this article. Full Length Research Paper The cost of environmental lead (Pb) poisoning in Nigeria Oladele A. Ogunseitan* and Timothy R. Smith Program in Public Health, College of Health Sciences, University of California, Irvine, CA 92697-7070 USA. Accepted 17 October, 2018 The pervasiveness of human health impacts and ecosystem effects of lead (Pb) is not controversial, but there are serious arguments about the pace at which Pb should be eliminated from consumer products. Presumably, these arguments can be resolved by converting costs and benefits of Pb use to similar units, a notorious methodological challenge for health impacts in developing countries. To estimate the costs of Pb poisoning attributable to petrochemicals in Nigeria, we conducted a meta-analysis of measured blood lead levels (BLL) and we used published Relative Risk values for disease categories to estimate the proportion of overall disease burden attributable to Pb. We modeled the health costs of Pb exposure and we compared this to the cost of banning Pb. We estimate that Pb exposure accounts for 7 25% of the disease burden among Nigerian children, costing the health and education sectors $0.38 – 1.15 billion year -1 for every 1 mg/dL increase in BLL. In comparison, we estimate that a Pb abatement program in Nigeria will cost $0.076 – 0.23 billion year -1 . If a Pb phase-out program is instituted now to lower the national BLL to 1 mg/dL by 2020, a savings of $2.7-8.0 billion would be realized. Key words: Lead (Pb) poisoning, Cost-benefit analysis, Diseases, Petrochemicals Africa. INTRODUCTION Exposure to Pb is widely recognized as a major risk factor for several human diseases, and the structure of industrial ecological systems have made exposure to Pb unavoidable for most people alive today (Needleman, 1999; Pruss-Ustun et al., 2004; WHO, 2000). In affluent countries, sizable investments in the implementation of environmental policies prohibiting the addition of Pb to many consumer products have resulted in rapid decline of human exposures, demonstrable by observed reduc- tions in the human blood content of Pb (USEPA, 1985; Grosse et al., 2002). Unfortunately, the public health gains from extensive research on the adverse effects of Pb and the remarkable successes of effective policies in these industrialized countries have not yet enveloped developing countries, and the course of gasoline-fueled industrialization remains hazardous to public health (OECD, 1999). *Corresponding author. E-mail: Oladele.Ogunseitan@uci.edu. Phone: 949-824-6350 Fax: 949-824-2056. Children throughout Africa are particularly vulnerable to Pb exposure because of unabated use of leaded gasoline and lead- acid batteries in automobiles (Nriagu et al., 1996 and 1997; Omokhodion, 1994), and recently, unre- gulated cottage industries associated electronic waste recycling (Lincoln et al., 2007). Particular socio- ecological and climatic factors also contribute to high levels of inhalation and ingestion of Pb-laden aerosol and dust (Laidlaw et al., 2005; Ogunfowokan et al., 2004; Ogun-sola et al., 1994; Rankin et al., 2005) . Despite the initiation of phase-out programs in a few countries, the gasoline sold in most African countries contains 0.5 - 0.8 g/l lead, the highest levels in the world (Thomas, 1995). In Nigeria, gasoline with average Pb content of 0.66 g L -1 remains in use (Fakayode and Olu-Owolabi, 2003) . In Nigeria’s largest city of Lagos, specific emissions of lead exceed 164 kg km -2 representing approximately 20% of the 2.46 Gg of lead emissions nationwide (Obioh et al., 1988), and ambient air concentration of Pb ranges up to 9.58 g m 3 , exceeding WHO recommended annual ave- rage of 0.5 g m 3 at all locations (Obioh et al., 2005). Furthermore, mean blood lead levels (BPb) measured at various times and urban locations in Nigeria have ranged from 11.4 – 25 g dL -1 ; far exceeding the 10 g dL -1 act- ion dose recommended for the U.S. population (Adeba- mowo et al., 2006; Ademuyiwa et al., 2005; Nriagu et al., 1997). In addition to automotive and industrial sources, eleva- ted blood lead levels in children have been attributed to paint, household dust, overcrowding and low parental income (Charney, 1982; Kapu et al., 1989; Kristensen et al., 1993; Landrigan et al., 1976; Nriagu and Pacnya, 1988). Previous studies in Africa have also shown that one of the strongest indicators of childhood BPb was the family either owning a car or living in a house located on a tarred road (Nriagu et al., 1996). These factors are typically only encountered in urban centers. However, the geochemical behavior of Pb and its association with sus- pended particulates suggests that children in remote suburban or rural regions may also suffer from Pb expo- sure, in which case, the adverse affects of Pb should be widespread. This hypothesis has not been rigorously tes- ted within the African continent. Also, it has been rela- tively simple to quantify the financial costs associated with Pb-phase out programs, but the economic costs of health effects attributable to lead exposure are typically externalized. This has made it difficult for policymakers to comprehend cost-benefit scenarios used to justify lead abatement programs. The goal of this research is to provide cost-benefit information to environmental policy makers in Nigeria by employing a quantitative comparison of the health cost of lead-related disease burden to the cost of a national lead abatement program. There are three research objectives: (1) the determination of the representative blood-lead content of Nigerian children (ages 1 - 6 yrs.) and subse- quent contribution of environmental lead exposure to the burden of disease in Nigeria; (2) the estimation of the health costs of environmental lead exposure in Nigeria; (3) and the estimation of the cost of a national lead- abatement program. METHODS Assessment of lead exposure Children (ages 1 – 6 years; N = 306) were recruited for this study through the scheduled immunization clinic in the semi-rural region of Otukpo, Nigeria (total population of approximately 136,800 people, of which 45% are younger than 14 years for the study period (Population Reference Bureau, 2006). Blood lead concen- trations were determined by means of an automatic blood lead analyzer with a sensitivity range of 1.4 - 65 µg dL -1 based on blood sample volume of 50 µl (LeadCare, ESA Inc., Chelmsford, MA and AndCare Inc., Durham, NC. The equipment was kindly provided by the U.S. Centers for Disease Control and Prevention, Atlanta, Georgia). The necessary size of the population sample was esti- mated within the desired margin of error for predicting the popu- lation mean according to Moore and McCabe (2005): n  Z  s 2  2.96  3.8 2  300 m.65 where: Z = z-score (2.96, 99% CI) ; s = standard deviation (3.8 µg dL -1 ; Nriagu et al., 1996); m = desired margin of error (± 0.65 µg dL -1 ) Informed consent was obtained for all human subjects according to standard research ethics, and as approved by the Institutional Review Board. Exclusion categories included those previously treated for Pb poisoning, those who had not been living in the same residence for at least the past 6 months, those who are being treated for severe illness, and those not accompanied by a legal guardian. In addition to the determination of BPb concentrations, a questionnaire was completed by each child subject with the legal guardian to record demographic and socioeconomic statistics and to assess predictors of Pb exposure and the predominant pathways for such exposures. The questionnaire survey was modified from the standard instrument used by U.S. Center for Disease Control and Prevention to better capture the social, economic, and cultural environment of Nigeria. With written consent, the nurse/phleboto- mist administered the survey and offered the subject a fact sheet containing health information on lead exposure in children. Association of lead exposure and disease burden Lead exposure is implicated in several disease burden categories including systemic effects such as hypertension, gastrointestinal effects, anemia, nephropathy, and nervous system effects such as Intelligence Quotient (IQ) defects and encephalopathy (ATSDR, 1999; Schwartz, 1991, 1993, 1994; Schwartz et al., 1986). We estimated the contribution of Pb exposure to the following disease categories in Nigeria: genito-urinary disease, prematurity, dental caries, nervous system cancers, congenital anomalies, hyperten- sion, cerebrovascular disease, low birth weight, and mild mental retardation (MMR; IQ levels 50-69) . Nine of the 106 disease cate- gories included in the World Health Organization’s Global Burden of Disease study were included in this study (Murray and Lopez, 1996; but see Cooper et al., 1998). A population-adjusted, disease burden for Nigeria was estimated from the regional burdens for relative risk analysis. The numerical model DISMOD ® was used to estimate disease burden for two disease categories that were not included in the GBD, prematurity and mild mental retardation (http://www.hs- ph.harvard.edu/organizations/bdu/DisMod.html). Our estimate of Pb-associated MMR presented a special cha- llenge. Pruss-Ustun et al. (2004) estimated the prevalence of men- tal retardation and cognitive impairment from known, non-congeni- tal causes (those mentioned above), compared values of developed and developing countries, and estimated a rate accounting for the increase of risk of mental retardation in developing countries, as follows: AR  P R  P baseline  P MR standard P MR standard Where: MR = mental retardation; PR = region-specific prevalence of MR from known causes; Pbaseline = prevalence of MR from known, non-congenital causes in developed countries; PMR standard = prevalence of MR according to the standard distribution of IQ score; AR = adjustment ratio That lead exposure contributes to IQ deficit is universally accep- ted, but there is no consensus on the dose response relationship (Lanphear et al., 2000; Moore et al., 1977; Pocock et al., 1994; Table 1. Variables for the cost of lead abatement in Nigeria. Cost ($/liter) Consumption Unleaded 0.01 *6,837 Gasoline Non-Pb 0.01 6,837 Abatement Additive Refinery 0.006 1,408 Factors Retooling Tetraethyl 0.002 6,837 Lead (TEL) Domestic 0.16 1,408 Gasoline Gasoline Foreign 0.16 5,429 Source Gasoline Total 0.16 6,837 Gasoline *(U.S. DoE, 2000) Lynn and Vanhanen, 2002; Stouthard et al., 1997). Based on the meta-analysis conducted by Popcock et al. (1994) and by Schwartz (1994), we relied on the following categories defined by three levels of exposure to Pb measured by blood Pb content. Children with relatively low BLLs (5 - 8 g/dL) suffer a 1.0 IQ deficit; those with medium BLL (9 - 15 g/dL) suffer 2.0 IQ deficits, and children in the high Pb exposure category (> 16 g/dL) suffer 3.0 IQ deficit. Pruss-Ustun et al. (2004) estimated lead-induced MMR to be 0.385/1000 for Sub-Saharan Africa (SSA) populations, compared to 0.256 per 100 people in Europe. We judged this estimate to be inadequate for Nigeria based on the assumption of global average IQ score of 100. Instead, we relied on the baseline IQ estimates of Lynn and Vanhanen (2002) that are more localized in perspective, providing average IQ scores for SSA and Nigeria as 70 and 67, respectively. The present study also departs from the Pruss-Ustun et al. (2004) assessment in the following way. Instead of extracting the fraction of lead-induced MMR from an overall MMR rate in Nigeria, an estimation of the IQ drop due exclusively to lead exposure was assessed on the basis of the range of measured BLLs and the IQ decrements attributed to those ranges in the clinical literature. To estimate the burden attributable to MMR, we adopted the approach used in a Dutch Burden of Disease Study where a severity weight of 0.06 was assigned for deficits in IQ between 1 - 4 points (Stouthard et al., 1997). The proportion of disease cases attributable to Pb exposure to an environmental risk factor (Attributable Faction) was based on Miettenen’s approach (1974): AFj  P(RR j  1) P(RR j  1)  1 where: AF j  the fraction of burden from some cause j (lead exposure); RR j  the relative risk of disease for cause j in the exposed to unexposed group; P = Prevalence of exposure. The attributable fraction was used to derive an estimate of the Lead Attributable Burden (LABD) for low, medium, and high Pb ex- posures given Relative Risks (or Odds Ratios) for each cause of death and disability related to the exposure, levels of exposure (pre Table 2. Summary of blood lead levels in children, ages 1-6, Otukpo. Mean %>10 Sex n [BPb] Range SD ug/dL Female 138 8.9 (2.1,23.8) 4.2 32.5 Male 168 9.8 (2.2,31.8) 4.8 35.0 Total 306 9.4 (2.1,31.8) 4.2 34.3 valence), and burden of disease due to each cause of death and disability in a given population: AB  AFj B j where: AB = Attributable Burden for a risk factor; AFj = Fraction of Burden from cause j Bj = population level burden of cause j Economic cost of lead exposure The U.S. EPA estimated the cost of a lead abatement program to be approximately 500 million dollars per year in 1985 (USEPA 1985). Estimates for the cost of a lead additive (Tetraethyl lead (TEL), $0.002/liter), refinery overhaul ($0.006/liter), and non-lead additive (Methy tert butyl ether (MTBE), $0.01/liter) were derived from Thomas and Kwong (2000). The average cost of gasoline in Nigeria was estimated to be approximately $.16/liter (Obioh et al., 2005). The annual consumption of domestic and imported gasoline in Nigeria is 24,260 and 93,550 barrels per day, respectively (US DoE, 2000). Thus, the total consumption of leaded gasoline in Nige- ria is 117,810 barrels per day (Table 1). Schwartz (1993) estimated that $17.2 billion dollars per year would be saved by a 1  g/dL red- uction in blood levels per year across the U.S. population. We used a similar approach to estimate the economic cost of lead exposure in Nigeria, but with modifications that capture issues specific to Nigeria and time differentials, including adjustments according to the consumer price index (CPI), and gross national income in pur- chasing power parity (GNI-PPP) of 2.3% for the study period (Population Reference Bureau, 2006). RESULTS AND DISCUSSION Blood lead levels Blood lead levels measured in children of Otukpo are summarized in Table 2. The mean for all children was 9.4 g/dL (SD = 4.2, n = 306). The mean value for males (55% of the sample; Table 3) was not significantly higher than for females. The highest BLL measured was 31.8 g/dL, which is below the U.S. standard of 45 g/dL for lead poisoning treatment with chelation therapy. The proportion of children having BLL above the USEPA action level of 10 g/dL is more than one third. Figure 1 shows a comparison of BLL distribution among children residing in Otukpo with previous reports of blood lead levels for children in the more urbanized city of Kaduna and other distantly located cities (Nriagu et al., 30 P o p u la ti o n 25 20 Otukpo 15 Kaduna 10 % 5 0 5 7 9 11 13 15 17 19 21 Blood Lead Concentration (ug/dL) Figure 1. Blood lead levels measured in Nigerian children. Table 3. Summary of demographic characteristics in children, ages 1 - 6, Otukpo. Characteristics Percentage Gender Male 54.9 Female 45.1 Age of Child 1 Year 19.9 2 Years 18.3 3 Years 15.0 4 Years 13.7 5 Years 15.4 6 Years 17.6 Born in Otukpo Child 87.9 Mother 42.8 Father 34.6 Average Household Size 6.8 People Maternal Literacy 64.7 Education Level Mother Father 0-4 Years 61.5 55.6 5-8 Years 17.9 21.6 9-12 Years 18.2 15.0 >12 Years 2.3 7.8 Occupation Mother Father Self-Employed 54.6 30.9 Professional 10.1 15.4 Factory Worker 1.0 4.9 Homemaker 14.1 0.0 Farmer 13.4 27.8 Other 13.1 18.6 Years Child has Lived in Current Residence 1 Year 28.1 2 Years 20.9 3 Years 15.0 4 Years 12.4 5 Years 10.1 Table 3. Contd. 6 Years 12.1 Type of Housing Detached 21.2 Attached 62.4 Apartment 15.4 Other 1.0 Housing Construction Material Brick/Block 98.0 Wood 0.7 Other 0.7 Unknown 0.7 Source of Drinking Water Pipes 29.7 Public Faucet 1.6 Well 61.8 Barrels 2.3 Bottled 1.6 Combination 3.0 Time Spent Away From Home by Child 0 Hours 84.3 1 Hour 0.3 2 Hours 0.7 3 Hours 2.9 4 Hours 2.6 >4 Hours 9.4 Children That Wash Hands 40.8 Mothers that Cook/Store 36.0 Food/Water in Clay Pots 1997; Adeniyi and Anetor, 1999) . The population of Kaduna is approximately 1.5 million people in 2002. The mean BLL in Kaduna children ages 1 - 6 years old is 10.6 µg dL -1 (± 3.8); with total atmospheric emissions of Pb in the region being 150 tons annually, and 97% of that exposure coming from leaded gasoline (Nriagu et al., 1996; Obioh et al., 1988). Table 3 shows a summary of the Socio-Demographic data that was collected through the epidemiological survey. Almost 90% of the children were born in Otukpo, but less than half of the parents were indigenous. The average household size was approximately 7 individuals and most lived in attached compound houses constructed of cement bricks with groundwater wells being the source of drinking water. Mean BLL was significantly associated with household size, maternal literacy, parental occupa- tion, home floor type, time spent outside the home, residential proximity to a ceramics shop, and by parental employment in a print shop (p<.05), but not with age, parental education, housing construction type or detach- ment status, drinking water, and frequency of hand-to- Table 4. Deaths (x1000) and DALYs (x1000) from all Pb-linked diseases for males and females, ages 0-14. Deaths, 0-14 DALYs, 0-14 Pb-Disease Category male female male female Genito-Urinary Disease 16 13 710 541 Prematurity* 384 384 2,295 2,295 Dental Caries 0 0 129 127 Nervous System Cancers 7 6 270 210 Congenital Anomalies 32 33 2,455 2,628 Hypertension** 2 2 66 69 Cerebrovascular Disease 9 9 313 298 Pb-Mild Mental Retardation (MMR) 0 0 2,463 2,414 Low Birth Weight*** 262 234 9,827 8,873 Sub-Saharan Africa (SSA) 712 681 18,528 17,455 SSA,M&F 1,393 35,983 Nigeria 121 116 3,150 2,967 Nigeria, M & F 237 6,117 *DALYs calculated using DISMOD with incidence rates from (Antilla et al., 1995). **DALY data from Type I Diabetes, ***Low Birth Weight is the largest category within Perinatal Conditions Table 5. Pb-linked burden of disease percentages (BDPb%). Deaths DALYs male female male female PbBD% of SSA 2.42 2.75 1.82 2.04 PbBD% of SSA, 0-14 4.57 5.31 2.97 3.34 PbBD% of SSA, 0-14, m/f 4.90 3.14 PbBD% of Nigeria 14.25 16.18 10.71 11.99 PbBD% of Nigeria, 0-14 26.86 31.25 17.48 19.67 PbBD% of Nigeria, 0-14, m/f 29.06 18.58 mouth behavior (Ogunseitan and Smith, submitted). Lead-associated burden of disease estimates Table 4 shows the results for overall Deaths and DALYs by gender for children, ages 0-14, of Sub-Saharan Africa (SSA) and Nigeria. Table 5 shows the results by gender for lead-linked disease burden for children in Nigeria. The data are shown as a percentage of SSA burden, SSA childhood burden, Nigerian burden, and Nigerian child- hood burden. Table 6 shows the medium estimate for DALYs of all nine disease burden categories by gender for children, ages 0-14, for both SSA and Nigeria. Also, the ORs that were found in the literature are shown. The three exposure categories are classified as low exposure (5-8 g/dL), medium exposure (9- 15 g/dL), and high ex- posure (>16 g/dL). There is no OR for lead-attributed mild mental retardation (MMRPb) required, because by definition, 100% of MMRPb is due to lead exposure. Table 7 shows the medium estimate of both the attributable risk and attributable burden for lead exposure across all three exposure categories for children, ages 0 - 14, in SSA and Nigeria. Also, the Pb-attributed burden of disease (BDPb) is shown as a percentage of the total Nigerian BD, and the total Nigerian childhood BD. Nigerian childhood BLLs of 5 - 8 g/dL account for approximately 2.18% of the tot- al Nigerian childhood burden, BLLs of 9 - 15 g/dL acco- unt for 7.50%, and BLLs >16 g/dL account for 5.07%. Combined all lead exposure accounts for approximately 14.74% of the total Nigerian childhood disease burden. Health costs of lead (Pb) exposure The estimates of childhood health costs of lead exposure are outlined in Table 8. The total costs are presented in millions of dollars. While all of the sub-categories (medi- cal, compensatory education, lost earnings, IMR, and neonatal care) show significant health costs of Pb expos- Table 6. Dalys and odds ratios for 9 Pb-linked diseases (Medium estimate). Pb-Disease Category DALYs, 0-14 OR @ 3 PbB Levels* male female total 5-8 9-15 >16 Genito-Urinary Disease 710 541 1251 1.0 1.9 3.8 1 Prematurity 2295 2295 4590 2.2 4.3 8.6 2,3 Dental Caries 129 127 256 6.8 9.6 4 13.5 4 Nervous System Cancers 270 210 480 2 5.5 5 11.0 5 Congenital Anomalies 2455 2628 5083 1.0 1.6 3.2 6 Hypertension 66 69 135 1.0 1.5 7 3 Cerebrovascular Disease 313 298 611 2.2 8 4.5 8 6.8 8 Pb-Mild Mental Retardation 2463 2414 4877 N/A N/A N/A Low Birth Weight 9827 8873 18700 1.2 2.4 4.7 9 Total SSA 18528 17455 35983 Total Nigeria 3150 2967 6117 *BLLs are presented in ug/dL. Not all the Odds ratios were available for all three blood lead levels in every disease category. Estimates were used in those cases. 1 (Antilla et al., 1995) 2 (Asien et al., 2000); 3 (Khera et al., 1980); 4 (Gemmel et al., 2002); 5 (Landrigan et al., 1976) 6 (Kristensen et al., 1993) 7 (Factor-Litvak et al., 1996) 8 (Gomaa et al., 2002) 9 (Kristensen et al., 1993). Table 7. Attributable risks and attributable Burden for 9 Pb-linked diseases (Medium estimate) AR for PbB Levels *AB for PbB Levels Pb-Disease Category 5-8 9-15 >16 5-8 9-15 >16 Genito-Urinary Disease 0.0 33.5 21.9 0 419 274 Prematurity 29.0 64.9 43.2 1,330 2,978 1,982 Dental Caries 6.8 9.6 13.5 17 25 35 Nervous System Cancers 25.4 71.6 50.0 122 344 240 Congenital Anomalies 0.0 25.1 18.0 0 1,278 917 Hypertension 0.0 21.9 16.7 0 30 23 Cerebrovascular Disease 29.0 66.2 36.7 177 405 224 Pb-Mild Mental Retardation 100.0 100.0 100.0 1,609 1,609 1,609 Low Birth Weight 6.4 43.9 27.0 1,191 8,218 5,050 Total SSA 4,446 15,306 10,353 Total Nigeria 756 2,602 1,760 % Nigeria BOD Attributable to Pb 1.40 4.80 3.25 % Nigeria BOD, Attributable to Pb (0-14) 2.18 7.50 5.07 *Attributable Burden is presented in DALYs (x1000) ure, lost earnings and increased IMR appear to have the largest impact on overall cost. The total childhood health cost was estimated to be $10.3 billion ($238 million GNI- PPP adjusted), or 29.8 billion naira annually for a 1 g/dL increase in BLL. Considering that the average BLL in Nigerian children is approximately 10 g/dL, the cost of lead exposure could be ten times higher than what is reported here. Thus, if Nigeria is able to decrease national BLL average by 5 g/dL, the country could gain more than $1 billion in savings annually from childhood health costs. Table 9 shows the results for the adult health costs of lead exposure. The total health costs are presented in millions of dollars. Mortality costs of hypertension–related deaths provide the driving force behind the bulk of the adult health costs, accounting for $6.6 billion out of $7 billion (94%) estimated for total adult health costs. Table 10 shows the estimates for the total health cost annually for the entire population. It also provides the annual per capita health cost of lead exposure, the annual health cost as a percentage of GNI-PPP, and the annual health cost as a percentage of the average per capita health ex- Table 8. Childhood health costs of lead exposure. Children Variable $(M) GNI-PPP Adjusted Million Naira Average blood lead concentration 9.8 ug/dL Number of children requiring 160,909 Medical Costs chelation therapy Cost of chelation therapy 1,920 Total Medical Costs 309 7 888 Number of children who receive 162,231 Compensatory education Education Cost of education 4,902 Total Compensatory Education 795 18 2,286 Cost Number children, age 6 3,515,600 Earnings Increase in earnings of a 1 ug/dL 1,920 reduction in BLL Total Earnings Lost 6,750 155 19,406 IMR 75/1000 1 ug/dL reduced maternal blood – 74.9/1000 IMR Infant Mortality Value of statistical life 4,429,840 Number of live births in Nigeria, 5,192,000 2002 Number of reduced deaths 519 Total IMR Cost 2,299.09 52.88 6,609.88 # of NICU admissions 1,752,300 Reduced NICU admissions 1,749,960 Neonatal Care Number of fewer NICU admissions 2,340 Cost of NICU 86,661 Total Neonatal Cost 202.79 4.66 583.01 Total Childhood Cost 10,356.03 238.19 29,773.58 expenditure. All of these health cost figures are for a 1 g/dL change in BLL. The total health cost is presented as a low, medium, and high value. The low value was calculated by subtracting the cost of compensatory edu- cation and NICU from the total. It is hypothesized that Nigeria could have significantly less compensatory edu- cation than the United States for children who are aca- demically challenged. Likewise, the frequency of children admitted into NICU in Nigeria could be much lower than the US. Based upon these assumptions, the low estimate for the health costs due to lead exposure is estimated to be approximately $377 million. The high value for health costs due to lead exposure was taken from Landrigan et al. (2002) who estimated that the health costs due to lead exposure for the cohort of children born in 2000 is app- roximately $43.4 billion (USD, 1997). This estimate was adjusted using both the Consumer Price Index (CPI) and the GNI-PPP ratio between the US and Nigeria (2.3%). The resultant health cost estimate after allowing for these adjustments is approximately $1.15 billion. Cost of lead abatement Table 11 illustrates the cost of a lead abatement prog- ram in Nigeria. The cost is a combination of four sub- categories: the cost the refinery upgrades, the cost of a non- lead additive, the cost of unleaded gasoline, and the cost of TEL. These sub-category costs are presented in $/Liter. To calculate the overall cost of the abatement program, the cost of TEL is subtracted from the summed costs of refinery upgrades, non-lead additive, and un- leaded gasoline. Using the national gasoline consump- tion provided by the Department of Energy (DOE), the medium overall estimated cost of a lead abatement pro- gram for Nigeria is approximately $194 million for the first year. This is approximately 48.5% of the health cost of a 1 g/dL increase in BLL per year g/dL. The low estimate, using the low estimate cost of $0.01 /L reported by the Organization for Economic Develop- ment (OCED) for lead phase out is $76 million per year (11). The high estimate, using the high estimate cost of Table 9. Adult health costs of lead exposure. Adults Variable $(M) GNI-PPP Adjusted Million Naira Medical costs Number of cases of hypertension 288,712 Hypertension Annual medical costs 812 Total Medical Cost 234.43 5.39 674.00 Number of cases of heart attacks 1,454 Heart attacks Medical costs 33,960 Total Medical Cost 49.38 1.14 141.96 Number of cases of stroke 591 Strokes Annual medical costs 26,574 Total Medical Cost 15.71 0.36 45.15 Lost wages Number of cases of hypertension 288,712 Hypertension Annual lost earnings 115.0 Total Earnings Lost 33.20 0.76 95.46 Number of cases of heart attacks 1,454 Heart Attacks Annual lost earnings 31,000 Total Earnings Lost 45.07 1.04 129.59 Number of cases of stroke 591 Strokes Annual lost earnings 17,716 Total Earnings Lost 10.47 0.24 30.10 Number of deaths 1,500 Mortality Value of statistical life 4,429,840 Total Mortality Cost 6,644.76 152.83 19,103.69 Total Adult Cost 7,033.02 161.76 20,219.94 Table 10. Total health costs of lead exposure. $M GNI-PPP † Million Low Estimate (2003) Adj. $M Naira Total annual health cost to Nigeria of 1 g/dL BPb *16,391 377 47,124 Annual per capita cost 126 2.90 362 Annual cost as percentage of GNI-PPP 0.36% 0.36% 0.38% Annual cost as percentage of per capita health expenditures 14% 14% 14% Medium Estimate Total annual health cost to Nigeria of 1 g/dL BPb 17,389 400 49,993 Annual per capita cost 134 3.08 385 Annual cost as percentage of GNI-PPP 0.38% 0.38% 0.38% Annual cost as percentage of per capita health expenditures 15% 15% 15% High Estimate Total annual health cost to Nigeria of 1 g/dL BPb **49,810 1,145 143,203 Annual per capita cost 383 8.81 1,102 Annual cost as percentage of GNI-PPP 1.10% 1.10% 0.38% Annual cost as percentage of per capita health expenditures 44% 44% 44% *Low estimate = Total health costs – cost of compensatory education and NICU. **High estimate = ($43.4 billion) (CPI, 2003), (49). † Million Naira. Table 11. Cost of lead abatement in Nigeria. Cost ($/liter) ‡ Cons. (10 6 Cost (M$/yr Cost (M$/yr Cost l/year) 1995) 2003) ( † MN/yr, 2003) Unleaded Gasoline 0.01 6,837 68 82 10,250 Abatement factors Non-Pb Additive 0.01 6,837 68 82 10,250 Refinery Retooling 0.006 6,495 39 47 5,875 Tetraethyl Lead (TEL) 0.002 6,837 14 17 2,125 Domestic Gasoline 0.16 6,495 1,039 271 33,821 Gasoline source Foreign Gasoline 0.16 342 55 66 8,250 Total Gasoline 0.16 6,837 1,094 1,313 164,148 Low estimate Total annual cost of abatement *75.6 24,250 Pb abatement cost / Pb health cost 0.189 0.189 Abatement as % of health cost 18.9% 18.9% Medium estimate Total annual cost of abatement 194 24,250 Pb abatement cost / Pb health cost 0.485 0.485 Abatement as % of health cost 48.5% 48.5% High estimate Total annual cost of abatement *227 24,250 Pb abatement cost / Pb health cost 0.567 0.567 Abatement as % of health cost 56.7% 56.7% *Low estimate = ($.01/L) (Liters consumed/year) (11). **High Estimate = ($.03/L) (Liters consumed/year) (11). ‡ Consumption, † Million Naira. $0.03/L reported by OECD, is $227 million per year (OECD, 1999). In conclusion, we have shown that lead exposure remains a major health risk factor in all Nigeria commu- nities, both rural and urban. The most important – and controllable – source of exposure is leaded automobile fuels. Arguments based on the enormous costs to society of switching to unleaded fuels are weak in the face of counterarguments based on the even more astounding health care and special educational costs associated with lead exposure. In the presence of alternative renewable fuels such as ethanol (Thomas and Kwong, 2000), the removal of lead from all fuels in Nigeria – and all coun- tries in sub-Saharan Africa – should not be delayed a sin- gle day further. ACKNOWLEDGMENTS This study was supported in part by funding and resour- ces provided by the Global Forum for Health Research, Switzerland; by the U.S. Centers for Disease Control and Prevention; and by the U.S. National Science Foundation (CMS-0524903). 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