TABLE 4
Case 4: Lead Isotope Ratios With Standard Error and Concentration for Whole Blood and Environmental Sources Sampled for Lead Isotope Analysis
206 Pb/ 204 Pb 2 σ /√n
207 Pb/ 204 Pb 2 σ /√n
207 Pb/ 206 Pb 2 σ /√n
208 Pb/ 206 Pb 2 σ /√n
Sample #
Sample
Sample Type
Lead (Pb) Concentration
1 Kitchen first draw 2 5-min flush (kitchen)
Tap water
18.3581 0.0006 15.6356 0.0005 0.85170 0.00001 2.07985 0.00003
3.388 µg/L
Tap water
18.4378 0.0009 15.6373 0.0008 0.84810 0.00001 2.07245 0.00003
0.105 µg/L
3 Living room rug 4 Bedroom carpet 5 Large pressure cooker 6 Small pressure cooker
Wipe Wipe Wipe
17.8841 0.0006 15.6131 0.0006 0.87301 0.00001 2.11131 0.00003 17.7869 0.0004 15.6057 0.0005 0.87737 0.00001 2.11856 0.00003 17.3334 0.0005 15.5811 0.0005 0.89890 0.00001 2.14941 0.00003
0.1 µg/ft 2 0.2 µg/ft 2 43.7 µg/ft 2
Wipe
18.2844 0.0025 15.6383 0.0022 0.85528 0.00003 2.08393 0.00008
0 µg/ft 2
7 Bathtub
Wipe Wipe
17.9773 0.0003 15.5985 0.0003 0.86768 0.00001 2.10208 0.00003 18.6121 0.0005 15.6562 0.0005 0.84119 0.00001 2.05947 0.00003
1.6 µg/ft 2 1.3 µg/ft 2
8 Bedroom windowsill 9 Halloween pumpkin 10 Entry carpet 11 Black pepper
Wipe
18.2618 0.0008 15.6385 0.0006 0.85634 0.00001 2.08272 0.00003
0.1 µg/ft 2
Wipe
18.4166 0.0006 15.6520 0.0005 0.84988 0.00001 2.07266 0.00003
0.2 µg/ft 2 0.2 µg/g 0.4 µg/g 2.3 µg/g 0.7 µg/g 0.1 µg/g 0.1 µg/g 0.1 µg/g 1.7 µg/g 0.1 µg/g 0.3 µg/g
Kitchen spice 17.5736 0.0029 15.5855 0.0029 0.88686 0.00004 2.13096 0.00018 Kitchen spice 19.0658 0.0006 15.7676 0.0005 0.82702 0.00001 2.06173 0.00004 Kitchen spice 17.5815 0.0005 15.6032 0.0005 0.88748 0.00001 2.13628 0.00003 Kitchen spice 17.4722 0.0006 15.5942 0.0007 0.89252 0.00001 2.13718 0.00003 Kitchen spice 18.9118 0.0033 15.7701 0.0031 0.83387 0.00003 2.05695 0.00015
12 Pink salt 13 Turmeric
14 Chili powder
15 White salt
16 Cilantro powder Kitchen spice 17.7199 0.0028 15.6279 0.0028 0.88199 0.00003 2.12744 0.00015 17 Cumin seeds Kitchen spice 18.0285 0.0039 15.6482 0.0036 0.86804 0.00004 2.11106 0.00015
18 Asafetida
Kitchen spice 17.4226 0.0005 15.5828 0.0005 0.89440 0.00001 2.14508 0.00003 Kitchen spice 18.4908 0.0075 15.6962 0.0068 0.84886 0.00007 2.09457 0.00028
19 Rai
20 Mango powder Kitchen spice 17.5334 0.0018 15.6214 0.0018 0.89095 0.00003 2.13850 0.00011
21 Wheat flour 22 Subject initial blood draw
Kitchen spice 17.5323 0.0424 15.4015 0.0374 0.87845 0.00020 2.12633 0.00053 Whole blood 17.6207 0.0008 15.5910 0.0008 0.88482 0.00001 2.13053 0.00004
0 µg/g
10.3 µg/dl
Note. The report unit for the lead isotope ratio is the atom ratio.
Discussion Our study demonstrates the application of LIA for source attribution among lead- poisoned children. In the six homes investi- gated, LIA identified lead-based paint, lead- contaminated dust, kajal, foreign ceremonial objects, and imported spices such as turmeric and black pepper as likely sources of lead poisoning. This technique was useful in rul- ing out exposures when interpreted along- side measurements of lead concentration and questionnaires about behavioral risk factors.
HUD questionnaire identified imported pow- ders and spices as main suspected hazards. LIA demonstrated that not only the bell (sample 3) but also other objects (samples 12 and 13) located on a religious altar where the family burned incense were similar to the blood in isotope concentration, suggesting lead expo- sure near the altar contributed to the child’s BLL. LIA indicated that the powders (samples 1 and 2) were not the primary suspected haz- ards because their isotopic compositions were dissimilar to the blood PbIR. The samples
closest to the blood isotope composition were dust wipes from the small lamp (sample 12), incense holder (sample 13), and masala pow- der (sample 9; Table 6). These samples were also most similar to the blood isotope composi- tion by minor isotope ratios (Figure 1, Case 6). After getting the LIA results, the family was advised to buy locally sourced spices and restrict access to the entire altar area. The child’s BLLs at 7, 8, 9, and 22 months decreased after the initial BLL and were 8, 7, 6, and 5 µg/dl, respectively.
15
May 2023 • our4'l o, 4</ro4me4:'l e'l:.
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