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

to be the more accurate ofthe two models. In our study, we also used the Murphy model (14) to estimate access to water from wells G and H. While we did not find an association between access to water from wells G and H and the concentrations ofAs and Cr in hair, our results do not contradict or otherwise bear upon the findings of Lagakos et al. (35) and the Massachusetts Department of Public Health (28). Our results merely indicate that Woburn residents who had access to water from wells G and H were no more likely to accumulate As and Cr in their hair than those who did not.

There is clear evidence that wells G and H were inducing recharge from the Aberjona river and that the river water con- tained elevated concentrations of As and Cr [as much as 70 and 240 pg/l, respectively (13)]; therefore, we were surprised not to have found evidence of exposure to As and Cr in the hair of Woburn residents. One possible explanation for our findings is that the concentrations of As and Cr estimated to have been present in the well water were in fact lower. We have recently found that the peadand (which separates the Aberjona river from the aquifer that supplied water to wells G and H) contains significandy elevat- ed concentrations of As and Cr (37), indi- cating that these peat deposits trapped As and Cr in the infiltrating river water. Ifsorp- tion to the peat were a major sink for As and Cr in the infiltrating river water, then our estimates ofAs and Cr levels in wells G and H water would have been too high. In the case of well H, it was also shown that sand lenses that permeate the peat act as preferen- tial flow paths and probably would not have appreciably removed As and Cr from the infiltrating river water. Nonetheless, these sand lenses are insufficiently conductive to explain the large influx of river water into the aquifer during pumping; therefore, other flow paths, which may or may not be sorp- tive for As and Cr, must exist.

The possibility that the concentrations of As in the well water were lower than our hypothesized values also seems to be sup- ported by the literature [Table 4 (21-24)]. Valentine et al. (21), Zhang et al. (22), and Khorvat (23) report that significantly elevat- ed concentrations (5- to 10-fold higher than the controls) ofAs were observed in the hair of people consuming drinking water con- taining in excess of 100-200 pg/l As. In light of these studies, the maximum amount ofAs (70 pg/l) hypothesized to have been in water from wells G and H should have been high enough to cause discernible increases in the amounts of As incorporated in the hair ofWoburn residents who drank this water.

Only one study relating levels of Cr in hair to concentrations in drinking water was

found. Rosas et al. (24) found that residents of Lecheria (central Mexico) exposed to 900 pg/l of Cr in their drinking water had Cr levels in their hair of 5.1 ± 4.3 pg/g (arith-

metic mean ± SD), while the control popu- lation in Mexico City, which drank water with an average of 20 pg/l Cr, had Cr levels in their hair of 0.68 ± 0.50 pg/g (arithmetic

Table 3. As and Cr concentrations reported in human hair

Samples

Review of a variety of studies Review of selected studies Diverse population

Diverse population

Rural and nonindustrial Diverse populationh Urban/suburban

Urban, no known industrial exposure Tannery workers Control subjects No access to well water Access to well

water

Arsenic

0.084 (1.9)9

80

0.01 (1.32)9

234

0.08 (1.9)9

37

0.11 ±0.10f

-

-

228

0.10 ± 0.08f

0.13 (3.0)9

Number

(pg/g)

-

-

27

    • 0.21

      ± 0.16f

    • 0.14

      (2.6)9

Concentration

-

-

0.46 (2.28)9

-

-

-

-

55

0.22 ± 0.30f

0.08 (2.2)9

1,250i 0.65 ± 0.70f

Range

    • 0.083

      -96a

    • 0.13

      -3.71c

    • 0.016

      -0.61e

0.008-0.67

- -

    • 0.02

      -0.43

    • 0.02

      -8.17

- -

    • 0.009

      -1.9

    • 0.017

      -0.63

34

0.58 (2.0)g

-

(33)

-

-

-

(34)

Range 0.09-33b

Reference (19)

0.13-3.65d

(29)

0.23-1.02e 0.15-16

(30) (31)

-

(32)

(17)

(18) (18) This study

71

0.59'

0.31-1.08

53

0.12'

0.079-0.199

55

2.82 ± 2.59f

0.34-15

2.19 (2.0)9

Chromium

-

-

-

Concentration Number (pg/g)

27

    • 2.80

      ± 2.08f 0.93-9.5

    • 2.29

      (1.8)9

- - -

    • 0.82

      + 1.66"

    • 0.56

      (2.0)9

    • 0.21

      (1.13)9

90

- - -

121

35

1.16 ± 0.80

0.36-4.31

16

393 ± 31

328-462

45

0.57 ± 0.45

0.08-2.42

23

98 ± 2.2

95-105

21

0.50 ± 0.37

0.01-1.39

10

123 ± 16

107-163

25

0.48 ± 0.44

0.07-0.44

17

51 ± 13

33-76

10

0.15 ± 0.11

0.04-0.39

17

<6.0

-

go, 90C

5.17

-

-

580

-

3.25

-

-

580

-

83d

0.71

-

-

3

-

22

3.81

-

-

-

>250

47

1.78

-

-

-

50-250

110

1.63

-

-

-

10-50

80

0.59

-

-

-

<10

aRange of mean values reported in 29 different studies; studies include acutely exposed populations. bRange of mean values reported in 22 different studies; studies include acutely exposed populations. cRange of mean values reported in 15 different studies involving normal (healthy) sample donors. dRange of mean values reported in 11 different studies involving normal (healthy) sample donors. eRange of mean values for samples from five countries: Japan, India, Canada, United States, and Poland. fArithmetic mean ± standard deviation. gGeometric mean (geometric standard deviation). hHair donors were selected for lack of occupational exposure. iSamples were not washed prior to analysis. iMedian concentration.

(24)

SD, standard deviation. aA community in Bakersfield, CA. bSamples were taken from people who had endemic arsenism. cSamples were taken from people who did not have endemic arsenism. dSamples from control population. eSamples were collected in a region of central Hungary between the Danube and Tisa rivers. fCity in central Mexico.

Table 4. Arithmetic mean concentrations of As and Cr reported in human hair in relation to levels in drink- ing water

Arsenic Edisona Fallona Hidden Valley, NV Virginia Foothills, NV Fairfax, NV Xinjiang, China

Hungarye

(21)

93

5.1± 4.3

1.10-21

-

900

21-1100

89

0.68 ± 0.50

0.15-2.76

-

20

1-30

Location

(22)

(23)

Chromium Lecheriaf Mexico Ci

ty

Reference

Concentration in hair (pg/g)

Number

Mean ± SD

Range

Concentration in drinking water (pg/I)

Number

Mean ± SD

Range

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

1095

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