Study of Lead Level During Pregnancy by Application of Synchrotron Radiation Micro XRF
Yongpeng Tong
0
Huibin Sun
0
Qi Luo
0
Jinxing Feng
0
Xiaohong Liu
0
Feng Liang
0
Fen Yan
0
Ke Yang
0
Xiaohan Yu
0
Yulan Li
0
Jianmin Chen
0
0
J. Chen PerkinElmer Instruments (
Shanghai) Co
., Ltd.,
Shanghai 201203, China
In order to study the daily Pb absorption in fetus and to monitor the main Pb sources in prenatal fetus, we have investigated several cases of Pb distribution along the longitudinal axis of fetal hair. The changes of Pb levels in the pregnancy period, even the daily changes of Pb levels can be detected in the hair. Therefore, by analyzing the Pb distribution curves in the fetal hair and the living habits of their mothers, the main sources of Pb in the prenatal fetus can be evaluated. In our study, the main sources of Pb in the two cases of prenatal fetus studied here should be from the polluted aquatics.
-
Although lead poisoning is one of the oldest known work and environmental hazards, the
modern understanding of the small amount of lead necessary to cause harm did not come
about until the latter half of the twentieth century. No safe threshold for lead exposure has
been discoveredthat is, there is no known amount of lead that is too small to cause the
body harm [1]. The brain is the organ most sensitive to lead exposure [2]; therefore,
children are at greater risk of lead neurotoxicity than adults are [3]. Evidence suggests that
most of leads effects on a childs central nervous system are irreversible [4]. Children with
lead poisoning may thus have adverse health, cognitive, and behavioral effects that follow
them into adulthood [5]. In 1991, the US Centers for Disease Control and Prevention
(CDC) determined that primary prevention activities in children should begin at blood lead
levels (BLLs) >10 g/dL [6]. However, studies have repeatedly linked BLLs <10 g/dL in
children 15 years of age with decreased intelligence quotient (IQ) and impaired cognition
[7], and associations with attention and behavior problems are becoming increasingly
evident as well [8]. Strong and long-lasting neurobehavioral effects occur with BLLs as low
as 2 g/dL [9]. A recent risk assessment by the California Environmental Protection
Agency calculated that a 1-g/dL change in BLLs in the range of 110 g/dL results in a
population-level decrement of one IQ point [10]. Also, some of the behavioral effects
described in adolescents with early-life Pb2+ exposure are similar to those expressed in
schizophrenia patients [11, 12] and the emerging evidence from both human studies and
animal studies suggest that prenatal Pb2+ exposure may be a higher environmental risk
factor for a fetal brain and nervous system. So how to evaluate daily Pb absorption in fetus
is a problem which needs to be solved now.
As hair is a site of excretion of essential, nonessential, and potentially toxic elements, the
use of hair as a biopsy material for drug abuse detection has grown in recent years. An
element irreversibly incorporated into growing hair during the process of keratinization is
often proportional to the level of the element in other body tissues. Thus, elemental analysis
in hair has been used as a screening test for physiological excess, deficiency, or
maldistribution [13]. Clinical research also indicates that hair levels of toxic elements such as
arsenic, lead, mercury, cadmium, etc. are highly correlated with pathological disorders [14].
Especially, as shown in our previous report [15], the distribution of unnecessary element
such as Pb can also be analyzed by synchrotron radiation Micro XRF along the longitudinal
axis of a fetal hair. From the Pb distribution along the longitudinal axis of a fetal hair, the
daily Pb absorption in fetal tissues 12 months before birth can be evaluated and monitored
in. Therefore, by analyzing the Pb distribution curves in hair and Pb contents in several
main environmental samples, a specific period of Pb environmental exposure history can be
tracked and discussed. So hair Pb analysis by synchrotron radiation micro XRF can be used
to reveal the main way of environmental Pb exposure at early stage.
Material and Methods
Subjects: The 10 uncontaminated fetal hair samples were collected from the back heads
of those newborns (three girls, six boys) born between May and June of 2009 in
Shenzhen Childrens Hospital. Among those samples, two strands of hair were
collected from one boy for Pb identical distribution analysis and one strand of hair was
collected respectively from the other children.
Sample processing: The collected hair samples were never dyed or treated by chemical
agents. Hair samples were washed three times with ethanol and wiped with nylon
cloths then washed with pure water. After drying in air, the hair 1.5 cm in length was
fastened by tape onto a sample holder.
XRF analysis: The micro XRF analysis was carried out in BL15U1 beam line of SSRF
(Shanghai Synchrotron Radiation Facility). The hard X-ray energy and flux range (6
1,010 phs/s at 10 keV, 200 mA, and 1618 keV) and the be (...truncated)