We conducted a human monitoring survey in Dong Mai, a battery recycling village in Vietnam, to assess exposure status to Pb.. Lead level was measured in hair, blood and urine samples of
Trang 1S P E C I A L F E A T U R E : O R I G I N A L A R T I C L E End-of-Life Vehicle (ELV) Recycling
Exposure assessment of lead to workers and children
in the battery recycling craft village, Dong Mai, Vietnam
Takako Noguchi•Takaaki Itai•Nguyen Minh Tue•Tetsuro Agusa•
Nguyen Ngoc Ha•Sawako Horai •Pham Thi Kim Trang•Pham Hung Viet•
Shin Takahashi•Shinsuke Tanabe
Received: 19 January 2013 / Accepted: 19 June 2013
Ó Springer Japan 2013
Abstract Human exposure to lead (Pb) due to
uncon-trolled Pb-acid battery recycling has been an environmental
health issue in newly developed industrial regions We
conducted a human monitoring survey in Dong Mai, a
battery recycling village in Vietnam, to assess exposure
status to Pb Lead level was measured in hair, blood and
urine samples of residents in Dong Mai and two reference
sites during 4 years spanning 2007–2011 In Dong Mai, Pb
levels in three matrixes were significantly higher than those
in reference sites Blood Pb levels of all adults and children
exceeded 10 lg/dL, the Centers for Disease Control and
Prevention definition of an elevated blood Pb level Clear
increase of urinary d-aminolevulinic acid (ALA) level with
increasing blood Pb level indicated disruption of heme
synthesis One adult exceeded 100 lg/dL of blood Pb,
where encephalopathy is of concern The blood Pb levels
achieved various toxic effect threshold values, and elevated
blood Pb was not limited to recycling workers, but was also
in children and women of reproductive age Serious
pollution status of Dong Mai village suggests an impor-tance of further monitoring surveys in various developing Asian countries
Keywords Pb battery Recycling Vietnam Risk assessment Lead
Introduction Lead poisoning remains one of the serious environmental problems in the world, due to prevalent environmental and occupational exposures Lead-acid battery recycling has become a widespread activity in many developing coun-tries [1], and it is an important source of Pb releasing into the environment The hazards of battery recycling have been reported in a series of studies on workers, their families and the environment of various developing coun-tries [2] Vietnam recorded the eighth highest economic growth in Asia [3], and has high resource demands In Vietnam, so called ‘‘craft village’’, which is defined as rural villages with existing craft and non-farming activities drawing the participation of at least 30 % of all households and making at least 50 % of the village’s total income, have greatly contributed to increased income and reduced pov-erty in rural areas It was estimated that ninety waste recycling craft villages are distributed across the country, mainly in the Northern part [4] Although establishment of craft village is an efficient solution to rural economic development, environmental problems are arising because
of the rapidly increasing craft production despite invest-ment for infrastructure being still poor Production in some craft villages, such as plastic, lead and metal recycling craft villages, typically leads to dangerous chronic diseases such
as cancer and heavy metal intoxication, due to manual
T Noguchi T Itai ( &) N M Tue T Agusa
N N Ha S Takahashi S Tanabe
Center for Marine Environmental Studies (CMES),
Ehime University, 2-5 Bunkyo-cho, Matsuyama,
Ehime 790-8577, Japan
e-mail: itai@sci.ehime-u.ac.jp
N M Tue P T K Trang P H Viet
Centre for Environmental Technology and Sustainable
Development (CETASD), Hanoi University of Science,
Vietnam National University, T3 Building, 334 Nguyen Trai
Street, Thanh Xuan District, Hanoi, Vietnam
S Horai
Recycling-oriented Environmental Science, Department
of Regional Environment, Faculty of Regional Sciences,
Tottori University, 4-101 Koyama-cho Minami, Tottori,
Tottori 680-0945, Japan
DOI 10.1007/s10163-013-0159-0
Trang 2procedures of recycling and poor understanding of workers
about environmental impacts [5] Dong Mai is such a
vil-lage in the Northern part of Vietnam, and has been
recy-cling Pb-acid battery for the past 40 years A local news
report suggested that of 259 households in the village, at
least 61 were involved in Pb recycling, totaling more than
500 workers [6] The General Department of
Environ-ment’s report in 2008 warned that Dong Mai villagers can
lose up to 10 years of their lifespan due to environmental
pollution Another report estimated that 71.1 % of residents
have mental diseases and 65.6 % have respiratory diseases,
and 100 % of workers suffer from chronic Pb poisoning
[7] Considering the situation in Dong Mai, quantitative
assessment of exposure status in the village residents is
necessary
In this study, human exposure to Pb was assessed in a
Pb-acid battery recycling site in Dong Mai We have
car-ried out sampling surveys in Dong Mai and two reference
sites since 2007 Screening of Pb levels in residents was
conducted via analysis of scalp hair, blood and urine
Health risk for residents was assessed by comparing blood
Pb level to the epidemiologically suggested threshold
val-ues of Pb intoxication Urinary d-aminolevulinic acid
(ALA) was measured as a biomarker of Pb-induced
ane-mia These surveys aim to elucidate exposure status and
health risk, as well as toxicological implications related to
battery recycling
Materials and methods
Study sites
Dong Mai village (hereafter DM) in Van Lam district,
Hung Yen province, Vietnam was chosen as a study site
DM is a small Pb-acid battery recycling craft village with
approximately 2300 residents Several hundred tons of
waste batteries were transported to DM every month, and
the estimated monthly production volume of Pb ingots was
250 tons Most business was family-based and batteries
were recycled in the backyard of each house
Urban control samples were collected from Hanoi city
(hereafter HN), the capital city of Vietnam, in 2008,
whereas rural control samples were collected from Duong
Quang village (hereafter DQ) in 2010 and 2011 Distances
to the reference sites from DM were ca 26 km and 9 km,
respectively
Sample collection
The primary screening surveys were conducted in DM and
HN in September 2007 and 2008 (hereafter ‘‘first survey’’),
whereas continued monitoring were conducted in DM and
DQ in January 2010 and 2011 (hereafter ‘‘second survey’’)
In both surveys, scalp hair, blood and urine were collected from the residents Cumulative participants of the first survey were 49 and 20 in DM and HN, respectively In the second survey, cumulative participants were 93 (including
23 children from 4 to 18 years old) and 71 (including 5 children) in DM and DQ, respectively (Table1) Sex, age, height and weight measurements, occupation, smoking and drinking habitats, hair length and residents time were recorded, and informed consents were obtained from all donors All samples were kept in gel ice immediately after collection and then sent to our laboratory in Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, and frozen at
-20°C The frozen samples were air transported with gel ice
to the Environmental Specimen Bank (es-Bank) at Center for Marine Environmental Studies (CMES), Ehime Uni-versity, Japan and stored at -25°C until analysis [8]
Chemical analysis of elements Human hair samples were washed in an ultrasonic bath with 0.3 % of polyoxyethylene lauryl ether and subse-quently dried for 12 h at 80 °C [9] Hair samples were digested in a mixture of concentrated HNO3and 50 % HF (5:1) in Teflon vials using a microwave system (Ethos D, Milestone S.r.l., Sorisole, BG, Italy) Human blood and urine samples were digested in HNO3with the microwave system Hot plate digestion was also employed for blood analyses at 200 °C for 3 h in Teflon vials The level of Pb was measured using an inductively coupled plasma mass spectrometer (ICP-MS; Agilent 7500cx, Agilent Technol-ogies, Tokyo, Japan) Rhodium was used for internal standards for correction of matrix effects and instrumental drift in ICP-MS measurements Accuracy and precision of measurements was assessed by analyzing standard refer-ence materials: NIES No 5 human hair and NIES No 18 human urine provided by National Institute for Environ-mental Studies (NIES), Japan and IAEA A-13 bovine blood provided by International Atomic Energy Agency (IAEA), Austria The recoveries of elements were in the range of 87–106 % of certified value
Urinary d-aminolevulinic acid analysis Determination of urinary d-aminolevulinic acid (ALA) was carried out by SRL Inc., Tokyo, Japan A brief procedure
of analysis was as follows The urine sample was mixed with in acetyl acetone, ethanol and formaldehyde solution and boiled The fluorescent derivative of ALA was ana-lyzed by high performance liquid chromatography coupled with a fluorometer
Trang 3Statistical analysis
All statistical analysis was performed with Statcel 2 (Seiun
Inc., Tokyo, Japan) and R software (version 2.14.0) The
Mann–Whitney U test was employed to verify significant
differences between DM and HN or DQ The Steel–
Dwass’s test was used to determine the difference in blood
Pb levels among six groups, i.e., adult male in DM, adult
female in DM, male children in DM, female children in
DM, adult male in DQ, and adult female in DQ A p value
of less than 0.05 was considered as an indication of
sta-tistical significance, unless otherwise mentioned The data
below the limit of detection were included in the statistical
evaluation as an estimated 50 % of the detection limit
value
Results
Pb levels in hair, blood, and urine
The Pb levels in hair were determined only in the first
survey population The Pb level in hair was extremely high
in DM compared to HN (Table1) The median value ratio
of Pb between DM and HN were 27
The Pb level in blood was determined in both the first
and the second surveys Among the first survey population,
the Pb levels in DM were higher than HN (p \ 0.001)
(Table1), with the median value ratio of Pb being 6.1
Among the second survey population, blood Pb levels of 93
residents in DM were statistically higher than in DQ
(p \ 0.001) (Fig.1) The median value ratio of blood Pb
between DM and DQ was 11 In DM, blood Pb levels in the
second survey population were significantly higher than
that of first survey population (p \ 0.001)
Among the second survey population, blood Pb levels of
adult males were higher than those of females in DM
(p \ 0.01), whereas gender difference was insignificant among residents in DQ (Fig.1) Blood Pb levels of 23 children in DM were also higher than for residents in DQ (p \ 0.01) (Fig.1) In DM, blood Pb levels of children were comparable to those in females The median value ratio of blood Pb between children in DM and residents in
DQ was 9
The trace element levels in urine were determined only
in the first survey population In urine, the levels of Pb were significantly higher in DM than in HN (p \ 0.001), with the ratio of median values of Pb being 8.7
Table 1 Median and range of Pb concentration in hair (lg/g), blood (lg/dL) and urine (ng/g) in residents of DM and reference sites in first and second surveys
Hair (first survey) Blood (first survey) Blood
(Second survey)
Urine (first survey)
Dong Mai 51 (2.5–2300) n = 49 20 (5.5–110) n = 49 34 (14–122) n = 93 24 (3.1–200) n = 49 Adult male 120 (2.5–2300) n = 16 35 (14–110) n = 16 43 (23–122) n = 30 56 (12–200) n = 16 Adult female (n = 16) 48 (19–220) n = 33 20 (5.5–71) n = 33 36 (14–87) n = 40 20 (3.1–150) n = 33 Child (n = 16) N.A N.A 29 (17–48) n = 23 N.A.
Hanoi (first survey) and
Duong Quang (second survey)
1.9 (0.80–5.5) n = 20 3.3 (1.9–6.3) n = 20 3.3 (1.0–11) n = 71 2.7 (0.79–6.0) n = 20
Adult male (n = 16) 3.0 (0.96–4.3) n = 9 4.1 (2.3–6.3) n = 9 4.2 (2.3–10) n = 24 2.7 (1.5–6.0) n = 9 Adult female (n = 16) 1.7 (0.80–5.5) n = 11 2.8 (1.9–4.5) n = 11 2.7 (1.0–11) n = 42 2.8 (0.79–5.8) n = 11 Child (n = 16) N.A N.A 2.9 (2.0–5.0) n = 5 N.A.
N.A not available
Fig 1 The box-whisker plot of blood Pb levels among six groups Only the data obtained from the second survey were used The horizontal line indicates the median, the box covers the 25th–75th percentiles and the maximum length of each whisker is 1.5 times the interquartile range Points outside this show up as outliers Groups with the same letters do not have significantly different levels in Steel–Dwass’s test for multiple comparisons
Trang 4Relationship between blood Pb and urinary ALA
The ALA analysis was conducted for the second survey
population Urinary ALA levels in DM varied from 0.3 to
71 mg/L in DM, and were significantly higher (p \ 0.001)
than those of DQ (0.1–3.0 mg/L) The ALA levels
posi-tively correlated with blood Pb levels in DM (p \ 0.001,
r = 0.47), whereas these were not correlated in DQ
(p [ 0.05, r = -0.19) (Fig.2)
Discussion
Exposure level
The human monitoring data of this study demonstrated
serious contamination by Pb in DM residents The Pb
levels of scalp hair in DM were comparable to other
seri-ously contaminated sites, e.g., Singapore (mean 640, range
0.93–3500 lg/g) [10], Poland (mean 150, range
35–290 lg/g) [11] and the West Indies (mean 590, range
51–1500 lg/g) [12]
Similar to the scalp hair, blood Pb levels also indicated
serious exposure status Because blood Pb levels are a more
direct signature of Pb burden in the body than hair,
com-parison to the other sites is useful to evaluate potential of
health effect The blood Pb levels of this study were
comparable to those reported in other studies where some
health effects are observed, i.e., children in a backyard
battery repair shop in Jamaica, where 22 children were
hospitalized for Pb poisoning (mean 32, range 31–170 lg/
dL) [13]; hormone disruption of Taiwanese battery workers
(mean ± SD: 24 ± 12 lg/dL) [14]; and residents in a
Senegalese battery recycling area where 18 children died (mean 56, range 38–81 lg/dL) [1] Gender differences of blood Pb levels provided some information for exposure pathway Males showed higher blood Pb levels than females since they often are more likely to engage in the Pb smelting work, whereas females only dismantled waste batteries
It is worth noting that children also have higher level of blood Pb than those found at the reference site Therefore, environmental Pb contamination in DM was not limited to workers, but also local residents like children
Risk assessment for human exposure to Pb among second survey population
Health risk of Pb exposure was evaluated by comparing the blood Pb levels to the epidemiologically defined toxic effect thresholds Of the 93 residents, including 23 chil-dren, from DM, all had blood Pb levels exceeding the minimum toxic threshold values (10 lg/dL) recommended
by The Agency for Toxic Substances and Disease Registry [15] Blood Pb levels greater than this value may induce decreasing activity of heme biosynthesis enzymes and elevating blood pressure Since Pb is a cumulative toxicant that affects multiple body systems, such as neurological, hematological, gastrointestinal, cardiovascular and renal systems, continuous Pb-acid battery recycling could lead to serious health risk among residents Blood Pb levels greater than 100 lg/dL raise concern of encephalopathy [15] One adult corresponded to this blood Pb level, with it as high as
122 lg/dL Actually, this level is comparable to those reported in a serious Pb pollution site in Dakar, Senegal, where 18 children have died, possibly due to Pb exposure [1]
The urinary ALA levels supported possible manifesta-tion of toxic effect by the Pb exposure ALA level is an initial compound in the heme synthesis pathway, and its level in urine can be used as the signature of anemia, which
is the initial manifestation associated with Pb exposure The inhibition of ALA dehydratase (ALAD) by Pb causes
an increase in ALA in plasma, and consequently excretion
of ALA in urine [16, 17] Urinary ALA levels increased with blood Pb levels, suggesting that inhibition of ALAD occurred due to high Pb in blood (Fig.2) This clear rising trend, stated from around blood level [ 50 lg/dL, was almost consistent with the trend observed in a previous study [18]
Since Pb exposure was not limited to the adults but also children in DM, adverse effects for children are of partic-ular concern Children, with their nervous system in active development, are generally vulnerable to the neurotoxico-logical affects of Pb Higher gastrointestinal tract uptake ratio and hand-to-mouth behavior enhances risk for
0
10
20
30
40
50
60
70
80
Blood Pb (µg/dL)
: DM
p < 0.001, r = 0.47
: DQ
p > 0.05
Fig 2 Relationships between urinary ALA and blood Pb levels of
the participants in the second survey
Trang 5children [19] The minimum threshold blood Pb level
corresponding to adverse health effects are lower than
adults [20] The Center for Disease Control and Prevention
(CDC) recommends that children’s blood Pb levels greater
than 10 lg/dL require further monitoring [21] All 23
children surveyed in DM had levels greater than 10 lg/dL,
with a maximum of 48 lg/dL According to the field
observation and questionnaire survey, children were not
directly involved in the recycling activity in both smelting
factory and backyard recycling site Hence, this result
suggests two possibilities: 1) the extent of Pb
contamina-tion is already widely spread in the village; or 2) children
are actually involved in the recycling activity In either
case, the situation is serious
The current situation in DM is serious, and a more
severe situation may probably occur if urgent mitigation
activity is not taken up soon Lead is a well-known
cumulative toxicant and prenatal Pb exposure can occur not
only through current maternal environmental exposures,
but also through the mobilization of cumulative maternal
bone Pb stocks during pregnancy and lactation [22, 23]
Additionally, maternal Pb burden causes risk for the
fol-lowing generation, even after improvement of the
con-taminated environment [24] Seventy-two percent of the
women in DM were in reproductive age, and their median
blood Pb level was 36 lg/dL, which may be associated
with adverse birth outcomes [25–27] All the facts strongly
suggest that medical treatment such as chelating therapy is
urgently needed in the village, DM [28]
Conclusion
Serious contamination of Pb was confirmed in the Pb-acid
battery recycling site in Dong Mai village, Northern part of
Vietnam The blood Pb levels achieved various toxic effect
threshold values, and apparent enrichment in blood was not
limited to recycling workers, but was also in children and
women of reproductive age The manifestation of Pb
poi-soning was apparent by clear elevation of urinary ALA
levels
Considering the widespread Pb contamination in the
village scale, not only should further monitoring be
con-tinued, but providing a pollution control solution is also
needed Since the major exposure pathway is likely
inha-lation and/or ingestion of heavily contaminated soil and
dust in suspension, soil removal is an important solution to
prevent residents from further exposure A preliminary
screening using field portable X-ray fluorescence
spec-troscopy indicated that Pb level in soil is highest around a
smelting plant (up to 15 wt%), then decreases
exponen-tially with distance (unpublished) In the case of the battery
recycling site in Senegal, the Senegalese government and a
non-government organization (Blacksmith Institute) suc-ceeded in reducing symptoms of Pb poisoning in humans
by removal of soil from the high Pb region that exceeded
Pb content [1,000 mg/kg [29] We assume that the same treatment may be also effective in DM The estimated area
in which the soil Pb level exceeds 1000 mg/kg in Dong Mai is ca 10,000 m2 Hence, ca 2,000 m3of soil should be removed, assuming that effective removal depth is 20 cm
In the Senegal case, the budget to complete soil removal was USD 200,000 to remove 3,700 m3soil in 2 years In order to achieve such a mitigation program, establishment
of a cooperative framework by national and local govern-ments and non-government organizations is urgently needed
Finally, the result of this study is an alarm that similar situations may occur in other craft villages in Vietnam, and also in other Asian developing countries Since transport of waste material is not limited to national scale, the help of developed countries is important to improve the material recycling system in developing Asian countries
Acknowledgments This study was supported by Grants-in-Aid for Scientific Research (A) (No 25257403), ‘‘Global COE Program’’ and
‘‘Project for the Encouragement of Science/Math-Oriented University Students’’ from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) and Japan Society for the Promotion
of Science (JSPS) and Waste Management Research Grant (K123001) from the Ministry of Environment, Japan We also acknowledge the approval of the Photon Factory Program Advisory Committee (Pro-posal No 2009G632) The success of this investigation was thanks to the support and collaboration of donors and member of the health authorities in Dong Mai and Duong Quang village.
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