Introduction
Because of improper disposal of lead acid batteries and back yard
smelting operations, resulting in contamination of soil and the
environment, the high incidence of lead poisoning in Jamaica is of great
concern in urban Jamaica. (1) The Ministry of Health has been working in
collaboration with Public Health Inspectors as well as research
institutions to identify the sources of lead in the Jamaican
environment. The occupation of lead smelting has contributed to the many
problems faced by the poor communities in which they are located
island-wide.
In the past, areas of St. Catherine have been used for smelting
operations. The greatest contamination occurred in Frazer's Content
where the Jamaica Metal Refining Company Ltd. was established to recycle
lead from spent automobile batteries in the community formerly called
Red Pond, and employed and trained persons in the various recycling
techniques including smelting. (4) Despite well documented incidence of
lead poisoning by the International Centre for Environmental and Nuclear
Sciences (ICENS), blood transfusions have not been considered as a
potential source of lead exposure.
Cases of lead poisoning associated with indoor firing ranges as
well as outdoor ranges have been well documented in the USA by the
National Institute for Occupational Safety and Health (NIOSH). Other
persons who were engaged in jobs such as gas station attendants, armed
security guards, police officers, soldiers and petroleum refiners could
be among the high risk group for lead poisoning in Jamaica. This is of
concern as these occupations make up a significant number of the work
force and donor population. (5,10,11) Blood donated by persons who might
unknowingly be exposed to lead could end up in our country's blood
banks.
The utilization of blood transfusion in Jamaica to treat various
disorders is very significant in understanding its potential as a hidden
source of lead exposure. Blood transfusion can be a life saving
intervention. Therefore, safe blood and products must be made available.
In order to ensure safety, blood is screened for the diseases that are
transmissible through transfusion. Laboratory tests which totaled
314,957 for the year 2001 did not include blood lead testing. Among the
tests done annually are HIV, HTLV, Hepatitis B and C, Syphilis, Blood
Group of donors and recipients and antibody screens, among other tests
(Refer to Table 1 excerpt from the Ministry of Health Annual Report
2001).
In a study of lead exposure from blood transfusions in premature
infants, it was found that blood products such as packed red blood cells
could actually double the lead concentration of the unit of blood. The
doubling in concentration of lead in packed red cells was due to the
fact that lead is bound to the red blood cells. The preparation of
packed cells would actually reduce the diluting effect the plasma had on
the overall lead concentration. This study seeks to determine lead
concentrations in blood donated for transfusion. Recipients of blood
products are at risk of exposure to lead as there is no present protocol
to screen for toxic substances at our nation's blood banks.
Materials and methods
Several epidemiological studies have suggested an association
between the blood lead levels and occupation. A cross-sectional survey
of 510 blood donors attending the two blood banks in Kingston and St.
Andrew was conducted by randomly selecting subjects. Blood donors
included both males and females between the ages of 18 and 55 years. The
two blood banks were designated Site 1 UHB and Site 2 NBT. Ethical
approval was obtained from the University Hospital of the West Indies
and University of the West Indies Faculty of Medical Sciences Ethics
Committee (UHWI/UWI/FMS) and the Ministry of Health Ethics Committee.
Informed written consent was obtained from each donor prior to blood
collection. Five milliliters of blood was collected in [K.sup.+]EDTA
(1.5mg/ml) from each donor. Blood lead concentrations were measured by a
proven LeadCare[R] ASV blood-lead analyzer. Demographic data, including
occupations, of the donors were collected through a questionnaire
survey. Data analysis was done using Microsoft XLSTAT 2008 program.
Quality control procedures included analysis of standard reference
material for each batch of samples analyzed.
Results
The geometric mean blood lead level for all units was
1.38[micro]g/dl [+ or -] 4.0 (0.0628[micro]mol/L). The prevalence of
lead poisoning among blood donors was 3% considering the 10[micro]g/dl
safe-limit for children set by the US Centre for Disease Control and
Prevention. The prevalence of lead poisoning was higher in females than
in males.
The blood lead concentrations among the donated blood units ranged
from <1.4[micro]g/dl (detection limit) to 60[micro]g/dl. The
occupations with the highest geometric mean blood lead concentrations
were soldiers (3.9 [micro]g/dl), students (3.2[micro]g/dl), welders (2.2
[micro]g/dl) and drivers (2.2[micro]g/dl). Persons in occupations
related to clerical and administrative duties were found to have lower
blood lead concentrations (1.3[micro]g/dl). The maximum blood lead
concentrations obtained were 56.0 [micro]g/dl and 60[micro]g/dl among
soldiers and students, respectively. These values were above the limit
of 25 [micro]g/dl recommended by the Occupational Safety and Health
Administration (OSHA) for occupational exposure to lead.
It was found that persons who displayed elevated blood lead levels
were not necessarily among the high risk occupations but among the
unskilled and skilled category, which re-emphasizes the cause for
concern as lead is ubiquitous. The occupations and geometric mean blood
lead concentrations for all participating donors is shown in Table 2
above.
Discussion
Internationally, it was found that blood donations (n=999) at a
metropolitan blood bank in Los Angeles, USA, had a geometric mean blood
lead level of 1.0 [micro]g/dl +2.8/-0.4 [micro]g/dl. Also, donors
(n=385) at a blood bank in Morocco had a mean blood lead concentration
of 8.7 [micro]g/dl. On the other hand, male donors (n=630) at a blood
bank in Brescia, Italy, had a range of 4.3 - 46.9 [micro]g/dl and a
median blood lead concentration of 14.8 [micro]g/dl. If we consider any
possible contamination during collection and analysis to be negligible,
the higher mean blood lead concentration in Brescia, Italy, would
indicate that there are higher blood lead concentrations in the Italian
blood donor population than in Morocco, Jamaica and the United States.
Several parishes in Jamaica have been cited as having an unusually
high amount of lead in the soil. (1) ICENS has carried out research on
trace metals in Jamaica and has found significant amounts of lead in
areas of Kingston, St. Andrew and St. Catherine. Nevertheless, results
for Jamaican blood donors are currently lower than those reported for
Moroccans and slightly higher than those reported in Los Angeles, USA.
It is expected that blood donations from areas with higher lead
concentrations among the population will have a high frequency of
elevated blood lead levels. In contrast, higher frequency of lead
exposure would be expected in Jamaican areas such as Kintyre,
Frazer's Content (formerly Red Pond) and areas where illegal
backyard smelting operations take place. These areas are of significance
in terms of Public Health.
Ironically, members of the armed forces who are significantly
exposed to lead on the firing ranges are expected to donate blood at
least twice a year. This could be a potential source of lead exposure as
one firearms instructor was found to have blood lead levels of
56[micro]g/dl. However, it is quite understandable, given the nature of
occupations in the armed forces, that personnel might be in need of
blood at some time during their careers. Soldiers and policemen often
donate blood on behalf of their colleagues who have been injured on the
job as well.
Recommendation
Screening of blood donations for lead prior to pediatric
transfusion would be beneficial, particularly in areas where the
population's blood lead levels are known to be elevated due to
environmental pollution or nearby contaminated sites. This could also
reduce the cost of overall testing if lead screening could be done prior
to transfusion in cases in which there are serious contraindications.
Conclusion
The mean blood lead concentrations were within normal limits for
units collected at the blood banks. Therefore, blood recipients in
Jamaica are not at high risk of lead poisoning from blood transfusions.
Nevertheless, donors engaged in high lead risk occupations, such as the
armed forces, should be checked before inclusion among blood donors.
Acknowledgements
Special thanks to Prof. Gerald Lalor, the Director General of the
International Centre for Environmental and Nuclear Sciences. I would
like to thank my supervisors Prof. Harvey Reid, Physiology Department,
and Dr. Mitko Voutchkov, Department of Physics, University of the West
Indies. Also, assistance for this project was provided by The CHASE
Fund. I would like to also express my appreciation to the members of
staff at the participating Blood Collection Centers and the Head of the
National Blood Transfusion Services, for facilitating the study.
References
(1.) Anglin-Brown B.A. , Armour-Brown A., Lalor G.C., Preston J.,
and Voutchkov M.K., (1996) Lead in a residential environment in Jamaica,
Environmental Geochemistry and Health 18:129-133.
(2.) Balleova S., Manola M A., Rothenberg S J., (2001) Lead levels
in blood bank blood, Archives of Environmental Health. 56(4): 312-313
(3.) Bearer C F., O'Riordan M., and Powers R.,(2000) Lead
exposure from blood transfusion to premature infants, Journal of
Peadiatrics 137:549-54.
(4.) Burr G, Matte T D, Figueroa P, Ostrowski S, Jackson -Hunt L,
Baker E, (1991). Lead exposure from conventional and cottage lead
smelting in Jamaica, Journal of Environmental Contamination and
Toxicology, 21:03-71.
(5.) Fischbein A, Rice C, Sarkozi L, Kon SH, Petrocci M, Selikoff
IJ. Exposure to lead in firing ranges. JAMA. 1979 Mar
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(6.) Khassouani CE, Allain P, Soulaymani R. Lead impregnation in
inhabitants of the Rabat region (Morocco). Presse Med 1997;
26(36):1714-16
(7.) Lalor G.C. and Vutchkov M. (2000) Heavy metals in Jamaica part
5: Reduction of blood lead levels of children in a mine-waste
contaminated area, Jamaica Journal of Science and Technology, 11:23-25.
(8.) Landrigan PJ, McKinney AS, Hopkins LC, Rhodes WW, Jr, Price
WA, Cox DH. Chronic lead absorption. Result of poor ventilation in an
indoor pistol range. JAMA. 1975 Oct 27;234(4):394-397
(9.) Micciolo R, Canal L, Maranelli G, Apostoli P. Non-Occupational
Lead Exposure and Hypertension in Northern Italy. International Journal
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Kameaka J. Duncan, MT(AMT), CASMET, Clinical Laboratory Scientist,
University of the West Indies, Mona Campus, Jamaica
Table 1: Utlisation in Blood Transfusioin
Services: 1998-2001
Year Blood Rood Components Laboratory
Collected Requested Prepared Test
(Unit)
1998 26,303 34,946 5,943 319,669
1999 23,436 49,835 5,219 304,535
2000 25,935 37,311 5,341 317,523
2001 24,263 41,749 19,379 314,957
Kameaka J.
Duncan, MT(AMT),
CASMET, Clinical
Laboratory
Scientist, University
of the West Indies,
Mona Campus,
Jamaica
Table 1a: Demographic and social information
on donors attending blood banks UHB1 and
NBT2 in Kingston and St. Andrew
Variables Frequency Percentage
Gender (n-510)
Male 410 80 4
Female 100 19.6
Age in years
(N = 498)
17-19 18 3.5
20-25 115 22.5
26-30 98 19.5
31-39 139 27.3
40-49 94 18.4
50-53 33 6.5
59-71 1 0.2
Employment
Status (n=505)
Student 41 8.1
Professional 61 12.1
Skilled/Clerical 193 39.2
Semi skilled 130 25.7
Laborer 13 2.6
Other 62 12.3
Area of Residence
(n=506)
Urban 260 51.4
Suburban 59 11.6
Rural 187 37
Table 2: Occurrence of lead exposure among
eighteen (18) occupations of donors attending
blood banks UHB1 and NBT2 in Kingston and
St. Andrew
Geometric
mean blood
lead
Occupation Total Range Concentration
Accountant 11 0.9-1.3 1.0
Businessman 9 0.9-2.5 1.9
Carpenter 12 0.9-2.9 1.4
Chef 11 0.9-2.3 1.7
Driver 16 0.9-8.4 2.2
Electrician 10 0.9-3.7 2.0
Fire Fighter 8 0.9-2.1 1.4
Laborer 13 0.9-3.1 1.5
Policeman 8 0.9-3.7 1.4
Security Guard 24 0.9-4.9 1.5
Sales Representative 12 0.9-2.4 1.0
Self Employed 21 0.9-10.3 1.7
Soldier 25 0.9-56 3.9
Student 41 0.9-60 3.2
* Unemployed 22 0.9-4.3 1.8
Welder 7 1.4-3.3 2.2
Mason 5 0.9-4.7 1.5
Others (n=87) 251 0.9-3.6 1.3
All Occupations 506 0.9-60.0 1.85
* Please note that the category "Unemployed" was
included in the table of occupations for the
purpose of comparison only.