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Articles - Arsenic and chromium in hair samples from Woburn, MA

from wells G and H resulted in higher con- centrations ofCr in hair.

The mean concentrations of Cr in the hair samples are shown in Table 2. Figure 4B shows that the Cr data is not fitted well by

e i t h e r a s t a n d - a r d o r a l o g - n o r m a l d i s t r i b u t i o n ; t h u s , t h e a r i t h m e t i c a n d g e o m e t r i c m e a n c o n - c e n t r a t i o n s a r e p r e s e n t e d i n T a b l e 2 . T h e g e o m e t r i c m e a n c o n c e n t r a t i o n ( G S D ) o f C r in the hair of residents who had access to wells G and H water (1964-1979, with a c c e s s ) w a s 2 . 2 9 ( 1 . 8 ) p g / g ( n = 2 7 ) , w h i l e f o r t h e c o n c u r r e n t c o n t r o l g r o u p ( 1 9 6 4 - 1 9 7 9 , no access) the mean concentration was 3.11 (2.4) pg/g (n = 9). The mean concentration ~~~~~~~~~~~.... of Cr in the hair of all of the controls A\ No access| | cess to G and H water 7n ~

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(1938-1994, no access) was 2.19 (2.0) /g (n = 55). The arithmetic mean concentra- tions for these three groups were 2.80 ± 2.08 Wgg (n = 27), 4.78 ± 5.14 pg/g (n = 9), and 2.82 ± 2.59 pg/g (n= 55), respectively.

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Discussion

The concentrations ofAs and Cr in hair have been reported in many different studies. As shown in Table 3, As and Cr in hair have both been reported at concentrations ranging from <0.1 'g/g to >30 tig/g (29). A review of studies in which the hair of only healthy individuals was analyzed suggests that the normal ranges for As and Cr are roughly the same: 0.10-3.7 pg/g (17-19,29-34). In comparing our results with those in Table 3, we find that the concentrations ofAs and Cr in the hair of Woburn residents are consis- tent with what others have reported. The arithmetic mean concentrations ofAs and Cr in the hair ofWoburn residents who did not

Figure 2. Concentrations of (A) As (y = -0.lSx + 0.25, r= 0.36) and Cr (y= -1.20x + 3.59, r= 0.12) in hair samples from Woburn residents versus access to water from wells G and H (see Methods for explanation). The results shown are for hair samples that were cut between 1964 and 1979, the period during which wells G and H were in opera- tion. A least squares regression line is drawn in each plot to show the trend in the data.

Figure 3. Concentrations of (A) As and (B) Cr in hair samples from Woburn residents versus the year of the haircut. Hair donors that had and did not have access to water from municipal supply wells G and H are represented by the closed and open symbols, respectively. Well G was in opera- tion between 1964 and 1979; well H was in opera- tion between 1967 and 1979. Line in (A) is least squares regression (y= -0.0083x+ 16.52, r= 0.45).

Parameter

Parameter Estimate

Standard error

p-value

Year of haircut Access to

-0.0074 -0.12

0.0017 0.10

2.5 x 10-s 0.22

Table 1. Linear regression of As concentrations in hair upon year of haircut and access to wells G and H water

wells G and H

Group

Number

A-mean + SD8

G-mean (GSD)b

Median

Range

A-mean + SDI

G-mean (GSD)b

Median

Range

1938-1994, no access Male Female 1964-1979, with access Male Female 1964-1979, no access Male Female 1964-1979, all samples Male Female 1938-1963, no access Male Female 1982-1994, no access Male Female 1938-1994, all samples Male Female

55 19 36 27 7 20 9 6 3 36 13 23 26 7 19 20 6 14 82 26 56

0.22 ± 0.30 0.34 ± 0.44 0.16 ± 0.16 0.21 ± 0.16 0.28 ± 0.17 0.19 ± 0.15 0.20 ± 0.09 0.21 ± 0.07 0.18 ± 0.14 0.21 ± 0.14 0.25±0.13 0.18 ± 0.15 0.35 ± 0.40 0.65 ± 0.61 0.24 ± 0.18 0.10 ± 0.10 0.12 ± 0.07 0.09 ± 0.11 0.22 ± 0.26 0.32 ± 0.38 0.17 ± 0.16

0.13 (3.0) 0.22 (2.6) 0.10 (1.7) 0.14 (2.6) 0.24 (1.7) 0.12 (2.8) 0.18 (1.6) 0.20 (1.4) 0.14 (1.8) 0.15 (2.4) 0.22(1.5) 0.12 (2.6) 0.21 (3.0) 0.41 (3.0) 0.16 (2.6) 0.06 (2.6) 0.10 (1.7) 0.05 (2.8) 0.13 (2.9) 0.23 (2.3) 0.10 (2.9)

0.13 0.22 0.10 0.22 0.23 0.14 0.16 0.21 0.10 0.20 0.23 0.11 0.20 0.48 0.13 0.07 0.12 0.05 0.14 0.22 0.11

0.009-1.9 0.009-1.9 0.018-0.62 0.017-0.63 0.11-0.63 0.017-0.45 0.091-0.34 0.14-0.31 0.091-0.34 0.017-0.63 0.11-0.63 0.017-0.45 0.019-1.9 0.046-1.9 0.019-0.62 0.009-0.41 0.009-0.22 0.018-0.18 0.009-1.9 0.009-1.9 0.017-0.62

2.82 ± 2.59 3.80 ± 3.81 2.35 ± 1.40 2.80 ± 2.08 3.00 ± 2.06 2.73 ± 2.14 4.78 ± 5.14 6.37 ± 5.76 1.60 ± 0.36 3.19 ± 3.16 4.55±4.36 2.58 ± 2.03 2.51 ± 1.70 2.92 ± 2.04 2.39 ± 1.50 2.43 ± 1.34 2.27 ± 1.57 2.49 ± 1.30 2.81 ± 2.42 3.59 ± 3.41 2.48 ± 1.69

2.19 (2.0) 2.56 (2.5) 2.02 (3.0) 2.29 (1.8) 2.59 (1.7) 2.19 (1.9) 3.11 (2.4) 4.37 (2.4) 1.58 (1.2) 2.47 (2.0) 3.30(2.1) 2.10 (1.8) 2.04 (1.9) 2.26 (2.1) 1.95 (1.8) 2.06 (1.9) 1.74 (2.3) 2.19 (1.7) 2.22 (1.9) 2.57 (2.3) 2.08 (1.8)

2.1 2.3 1.9 2.0 2.3 1.8 1.9 3.8 1.7 2.0 2.4 1.8 1.8 2.3 1.8 2.2 2.2 2.2 2.0 2.3 1.9

0.34-15 0.34-15 0.73-6.4 0.93-9.5 1.3-7.5 0.93-9.5 1.7-15 1.7-15 1.2-1.9 0.93-15 1.3-15 0.93-9.5 0.73-6.4 0.78-5.9 0.73-6.4 0.34-5.0 0.34-5.0 0.95-4.8 0.38-15 0.38-15 0.73-9.5

Table 2. Concentrations of As and Cr in hair samples

aArithmetic mean ± standard deviation. bGeometric mean (geometric standard deviation).

from residents of Woburn, Massachusetts, with and without access to water from wells G and H

Arsenic (pg/g)

Chromium (pg/g)

Environmental Health Perspectives * Volume 105, Number 10, October 1997

1093

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