African Journal of Environmental Science and Technology Vol. 1 (2), pp. 027-036, September 2007
Available online at http://www.academicjournals.org/AJest
© 2007 Academic Journals
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 7 August, 2007
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
1.15 billion year for every 1 µg/dL increase in BLL. In comparison, we estimate that a Pb abatement
-1
program in Nigeria will cost $0.076 – 0.23 billion year . If a Pb phase-out program is instituted now to
lower the national BLL to 1 µg/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 reductions 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:
[email protected].
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, unregulated 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; Ogunsola 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).
-1
In Nigeria, gasoline with average Pb content of 0.66 g L
remains in use (Fakayode and Olu-Owolabi, 2003). In
Nigeria’s largest city of Lagos, specific emissions of lead
-2
exceed 164 kg km 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
3
9.58 µg m , exceeding WHO recommended annual ave3
rage of 0.5 µg m at all locations (Obioh et al., 2005).
Furthermore, mean blood lead levels (BPb) measured at
028
Afr. J. Environ. Sci. Technol.
various times and urban locations in Nigeria have ranged
-1
-1
from 11.4 – 25 µg dL ; far exceeding the 10 µg dL action dose recommended for the U.S. population (Adebamowo et al., 2006; Ademuyiwa et al., 2005; Nriagu et al.,
1997).
In addition to automotive and industrial sources, elevated 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 suspended particulates suggests that children in remote
suburban or rural regions may also suffer from Pb exposure, in which case, the adverse affects of Pb should be
widespread. This hypothesis has not been rigorously tested within the African continent. Also, it has been relatively 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 subsequent 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 leadabatement 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 concentrations 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 estimated within the desired margin of error for predicting the population mean according to Moore and McCabe (2005):
2
n=
Z ×s
2.96 × 3.8
=
m
.65
2
= 300
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/phlebotomist 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, hypertension, cerebrovascular disease, low birth weight, and mild mental
retardation (MMR; IQ levels 50-69). Nine of the 106 disease categories 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.hsph.harvard.edu/organizations/bdu/DisMod.html).
Our estimate of Pb-associated MMR presented a special challenge. Pruss-Ustun et al. (2004) estimated the prevalence of mental retardation and cognitive impairment from known, non-congenital 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 =
PR − Pbaseline + PMR standard
PMR 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 accepted, but there is no consensus on the dose response relationship
(Lanphear et al., 2000; Moore et al., 1977; Pocock et al., 1994;
Ogunseitan and Smith
Table 1. Variables for the cost of lead abatement in Nigeria.
Cost
($/liter)
Abatement
Factors
Unleaded
Gasoline
Non-Pb
Additive
Refinery
Retooling
Tetraethyl
Lead (TEL)
Gasoline
Source
Domestic
Gasoline
Foreign
Gasoline
Total
Gasoline
*6,837
0.01
6,837
0.006
1,408
0.002
6,837
0.16
1,408
0.16
5,429
0.16
6,837
*(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 µg/dL) suffer a 1.0 IQ deficit; those with
medium BLL (9 - 15 µg/dL) suffer 2.0 IQ deficits, and children in the
high Pb exposure category (> 16 µg/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):
AF j =
Table 2. Summary of blood lead levels in children, ages 1-6,
Otukpo.
Consumption
0.01
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 exposures given Relative Risks (or Odds Ratios) for each cause of
death and disability related to the exposure, levels of exposure (pre
029
Sex
Female
Male
Total
n
138
168
306
Mean
[BPb]
8.9
9.8
9.4
Range
(2.1,23.8)
(2.2,31.8)
(2.1,31.8)
SD
4.2
4.8
4.2
% > 10
ug/dL
32.5
35.0
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 Nigeria is 117,810 barrels per day (Table 1). Schwartz (1993) estimated
that $17.2 billion dollars per year would be saved by a 1 µg/dL reduction 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 purchasing 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
µg/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
µg/dL, which is below the U.S. standard of 45 µg/dL for
lead poisoning treatment with chelation therapy. The
proportion of children having BLL above the USEPA
action level of 10 µg/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.,
030
Afr. J. Environ. Sci. Technol.
Table 3. Contd.
30
% Population
25
20
Otukpo
Kaduna
15
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
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
-1
µg dL (± 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 occupation, 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 detachment status, drinking water, and frequency of hand-to-
Ogunseitan and Smith
031
Table 4. Deaths (x1000) and DALYs (x1000) from all Pb-linked diseases for males and
females, ages 0-14.
Deaths, 0-14
Pb-Disease Category
male
Genito-Urinary Disease
Prematurity*
Dental Caries
Nervous System Cancers
Congenital Anomalies
Hypertension**
Cerebrovascular Disease
Pb-Mild Mental Retardation (MMR)
Low Birth Weight***
Sub-Saharan Africa (SSA)
SSA, M & F
Nigeria
Nigeria, M & F
female
16
384
0
7
32
2
9
0
262
712
13
384
0
6
33
2
9
0
234
681
1,393
121
116
237
DALYs, 0-14
male
female
710
541
2,295
2,295
129
127
270
210
2,455
2,628
66
69
313
298
2,463
2,414
9,827
8,873
18,528 17,455
35,983
3,150
2,967
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
PbBD% of SSA
PbBD% of SSA, 0-14
PbBD% of SSA, 0-14, m/f
PbBD% of Nigeria
PbBD% of Nigeria, 0-14
PbBD% of Nigeria, 0-14, m/f
DALYs
male
female
male
female
2.42
4.57
2.75
5.31
1.82
2.97
2.04
3.34
4.90
14.25
26.86
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 childhood 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 µg/dL), medium exposure (9-15 µg/dL), and high exposure (>16 µg/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
16.18
31.25
29.06
3.14
10.71
17.48
11.99
19.67
18.58
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 µg/dL account for approximately 2.18% of the total Nigerian childhood burden, BLLs of 9 - 15 µg/dL account for 7.50%, and BLLs >16 µg/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 (medical, compensatory education, lost earnings, IMR, and
neonatal care) show significant health costs of Pb expos-
032
Afr. J. Environ. Sci. Technol.
Table 6. Dalys and odds ratios for 9 Pb-linked diseases (Medium estimate).
Pb-Disease Category
Genito-Urinary Disease
Prematurity
Dental Caries
Nervous System Cancers
Congenital Anomalies
Hypertension
Cerebrovascular Disease
Pb-Mild Mental Retardation
Low Birth Weight
Total SSA
Total Nigeria
DALYs, 0-14
OR @ 3 PbB Levels*
male
female
total
5-8
9-15
>16
710
2295
129
270
2455
66
313
2463
9827
18528
3150
541
2295
127
210
2628
69
298
2414
8873
17455
2967
1251
4590
256
480
5083
135
611
4877
18700
35983
6117
1.0
2.2
6.8
2
1.0
1.0
8
2.2
N/A
1.2
1.9
4.3
4
9.6
5
5.5
1.6
7
1.5
8
4.5
N/A
2.4
3.8
2,3
8.6
4
13.5
5
11.0
6
3.2
3
8
6.8
N/A
9
4.7
1
*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);
(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).
4
Table 7. Attributable risks and attributable Burden for 9 Pb-linked diseases
(Medium estimate)
AR for PbB Levels
Pb-Disease Category
Genito-Urinary Disease
Prematurity
Dental Caries
Nervous System Cancers
Congenital Anomalies
Hypertension
Cerebrovascular Disease
Pb-Mild Mental Retardation
Low Birth Weight
5-8
0.0
29.0
6.8
25.4
0.0
0.0
29.0
100.0
6.4
9-15
>16
33.5
21.9
64.9
43.2
9.6
13.5
71.6
50.0
25.1
18.0
21.9
16.7
66.2
36.7
100.0 100.0
43.9
27.0
Total SSA
Total Nigeria
% Nigeria BOD Attributable to Pb
% Nigeria BOD, Attributable to Pb (0-14)
*AB for PbB Levels
5-8
0
1,330
17
122
0
0
177
1,609
1,191
9-15
419
2,978
25
344
1,278
30
405
1,609
8,218
>16
274
1,982
35
240
917
23
224
1,609
5,050
4,446 15,306 10,353
756 2,602 1,760
1.40 4.80
3.25
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 GNIPPP adjusted), or 29.8 billion naira annually for a 1 µg/dL
increase in BLL. Considering that the average BLL in
Nigerian children is approximately 10 µg/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 µg/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-
Ogunseitan and Smith
033
Table 8. Childhood health costs of lead exposure.
Children
Medical Costs
Variable
$(M)
Average blood lead concentration
Number of children requiring
chelation therapy
9.8 ug/dL
160,909
Cost of chelation therapy
Total Medical Costs
Compensatory
Education
Number of children who receive
education
Cost of education
Total Compensatory Education
Cost
Number children, age 6
Earnings
Increase in earnings of a 1 ug/dL
reduction in BLL
Total Earnings Lost
IMR
Infant Mortality
1 ug/dL reduced maternal blood –
IMR
Value of statistical life
Number of live births in Nigeria,
2002
Number of reduced deaths
Total IMR Cost
# of NICU admissions
Reduced NICU admissions
Neonatal Care
Number of fewer NICU admissions
Cost of NICU
Total Neonatal Cost
Total Childhood Cost
expenditure. All of these health cost figures are for a 1
µg/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 education and NICU from the total. It is hypothesized that
Nigeria could have significantly less compensatory education than the United States for children who are academically 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 approximately $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.
GNI-PPP Adjusted Million Naira
1,920
309
162,231
7
888
18
2,286
155
19,406
52.88
6,609.88
202.79
4.66
583.01
10,356.03
238.19
29,773.58
4,902
795
3,515,600
1,920
6,750
75/1000
74.9/1000
4,429,840
5,192,000
519
2,299.09
1,752,300
1,749,960
2,340
86,661
Cost of lead abatement
Table 11 illustrates the cost of a lead abatement program in Nigeria. The cost is a combination of four subcategories: 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 unleaded gasoline. Using the national gasoline consumption provided by the Department of Energy (DOE), the
medium overall estimated cost of a lead abatement program for Nigeria is approximately $194 million for the first
year. This is approximately 48.5% of the health cost of a
1 µg/dL increase in BLL per year µg/dL.
The low estimate, using the low estimate cost of $0.01
/L reported by the Organization for Economic Development (OCED) for lead phase out is $76 million per year
(11). The high estimate, using the high estimate cost of
034
Afr. J. Environ. Sci. Technol.
Table 9. Adult health costs of lead exposure.
Adults
Variable
$(M)
GNI-PPP Adjusted Million Naira
Medical costs
Hypertension
Heart attacks
Strokes
Number of cases of hypertension
Annual medical costs
288,712
812
Total Medical Cost
234.43
5.39
674.00
Number of cases of heart attacks
Medical costs
Total Medical Cost
1,454
33,960
49.38
1.14
141.96
Number of cases of stroke
Annual medical costs
591
26,574
Total Medical Cost
15.71
0.36
45.15
Number of cases of hypertension
Annual lost earnings
Total Earnings Lost
288,712
115.0
33.20
0.76
95.46
Number of cases of heart attacks
Annual lost earnings
1,454
31,000
Total Earnings Lost
45.07
1.04
129.59
Number of cases of stroke
Annual lost earnings
591
17,716
Total Earnings Lost
10.47
0.24
30.10
Number of deaths
Value of statistical life
1,500
4,429,840
Total Mortality Cost
6,644.76
152.83
19,103.69
7,033.02
161.76
20,219.94
Lost wages
Hypertension
Heart Attacks
Strokes
Mortality
Total Adult Cost
Table 10. Total health costs of lead exposure.
Low Estimate
$M
(2003)
GNI-PPP
Adj. $M
†
Million
Naira
Total annual health cost to Nigeria of 1 µg/dL BPb
Annual per capita cost
Annual cost as percentage of GNI-PPP
Annual cost as percentage of per capita health expenditures
Medium Estimate
*16,391
377
47,124
126
0.36%
14%
2.90
0.36%
14%
362
0.38%
14%
Total annual health cost to Nigeria of 1 µg/dL BPb
Annual per capita cost
Annual cost as percentage of GNI-PPP
Annual cost as percentage of per capita health expenditures
High Estimate
17,389
400
49,993
134
0.38%
15%
3.08
0.38%
15%
385
0.38%
15%
**49,810
1,145
143,203
383
8.81
1,102
1.10%
1.10%
0.38%
44%
44%
44%
Total annual health cost to Nigeria of 1 µg/dL BPb
Annual per capita cost
Annual cost as percentage of GNI-PPP
Annual cost as percentage of per capita health expenditures
*Low estimate = Total health costs – cost of compensatory education and NICU. **High estimate = ($43.4 billion) (CPI,
2003), (49). †Million Naira.
Ogunseitan and Smith
035
Table 11. Cost of lead abatement in Nigeria.
Cost ($/liter)
Unleaded Gasoline
0.01
Abatement factors Non-Pb Additive
0.01
Refinery Retooling
0.006
Tetraethyl Lead (TEL)
0.002
Domestic Gasoline
0.16
Gasoline source
Foreign Gasoline
0.16
Total Gasoline
0.16
Low estimate
Total annual cost of abatement
Pb abatement cost / Pb health cost
Abatement as % of health cost
Medium estimate
Total annual cost of abatement
Pb abatement cost / Pb health cost
Abatement as % of health cost
‡
Cons. (10
l/year)
6
6,837
6,837
6,495
6,837
6,495
342
6,837
Cost
Cost (M$/yr Cost (M$/yr
†
( MN/yr, 2003)
1995)
2003)
68
82
10,250
68
82
10,250
39
47
5,875
14
17
2,125
1,039
271
33,821
55
66
8,250
1,094
1,313
164,148
*75.6
0.189
18.9%
24,250
0.189
18.9%
194
0.485
48.5%
24,250
0.485
48.5%
*227
0.567
56.7%
24,250
0.567
56.7%
High estimate
Total annual cost of abatement
Pb abatement cost / Pb health cost
Abatement as % of health cost
*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 communities, 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 countries in sub-Saharan Africa – should not be delayed a single day further.
ACKNOWLEDGMENTS
This study was supported in part by funding and resources 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). Additional support was provided by the
Program in Industrial Ecology at UC-Irvine. We are grateful for the kind support provided by Dr. Sunday Ochenjele
at Mount Zion hospital, Otukpo; and by Shime-nenge
Imadu, Secretary of the Ethical Committee of the Ministry
of Health and Human Services, Benue State, Nigeria.
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