Hair Analysis Does Not Support Hypothesized Arsenic and Chromium Exposure from Drinking Water in Woburn, Massachusetts
Catriona E. Rogers,1'2 Aoy V. Tomita,1'3 Philip R. Trowbridge,1'2 Jec-Kong Gone,1'4 Jia Chen,1'3 Peter Zeeb,1'2 Harold F. Hemond,1'2 William G. Thilly, '3 lUhan Olmez, '4 and John L. Durant5
'Center for Environmental Health Sciences; 2Ralph M. Parsons Laboratory; 3Division of Toxicology; and 4Nuclear Reactor Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 USA; 5Civil & Environmental Engineering Department, Tufts University, Medford, MA 02155 USA
We hypothesized that residents ofWoburn, Masusets, had been exposed to as much as 70 pgl of arsenic (As) and 240 pg'l of chromium (Cr) in drinking water from municipal supply wells G and H. To test this hypothesis, we measured the concentrations ofAs and vC in 82 hair samples donated by 56 Woburn residents. Thirty-sir samples were cut beween 1964 and 1979-, the period during which wells G and H were in operation. The aind were cut either before 1964 (1938-1963; n = 26) or after 1979 (1921994; n 20). Washed hairsamples-were aia lyzed by instrumental neutron activation. Exposure to the well water-measured as access-was estimted using well pumping records and a model of the Woburn water distribution system. Our results show that access to wells G and H water was not sificantly correlated (95% confi-
dence intervl) with As and Cr concentrations measured in the hair ofWobu
idns, but As
c o n c e n t m t i o n s h a v e d e c l i n e d s i g n i f i c a n t d y o v e r t h e l s t h a l f c e n t u x y . i n e a r r e g r e s s i o n o f A s c o n - c e n t r a t i o n s ( m i c r o g r a m s p e r g r a m ) u p o n y e a r o f h a i r c u t a n d a c e s s t o w e l l s C a n d H w e r y i l 5 ) a i n d - 0 . 1 2 * ed a standard coefficient for year of-0.0074 t 0.0017 (standard error; p t.2.15x
0 . 1 0 ( p =
0 . 2 2 )
_ f o r a c c e s s . T h e r v a l u e f o r t h e m o d e l w a s 0 . 1 9 . 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 -
tions (geometric standard deviation) ofAs and Cr relative access esimate >0) to wells G and'H water
the hair of rident who had accss 27) were0.14 (2.6)-ad 2.29 (1.8)
_ i respectivelr the geometc mean concentratns ofAs and Cr in4'all ofthe hair samples rom res - dents who did not have access (1938-1994; a = 55) were 0.13 (3,0) and 2.19 (2.0) pg/ rspe
ater, hua hair, Woburn, M t i v e l y . K e y w o r k a r s e n i c c h r o m u m g E n v i r o n H e a l h P e r p e c t 1 0 5 : 1 0 9 0 - 0 9 7 ( 1 9 9 7 . / n p / / e h i s . n i e h s , n i h . g o v
Chemical manufacturing and leather tanning activities on the Aberjona River watershed in eastern Massachusetts (Fig. 1) have left a legacy of environmental contamination. The earliest records of contamination date to the 1 870s when it was reported that tanneries in Woburn were discharging their wastes into tributaries of Horn Pond, which then served as a drinking water supply for Woburn (1-3). Since that time, reports of additional contamination resulting from leather tan- ning, chemical manufacturing, and other industrial activities on the watershed have been made with alarming regularity (4,5). As a result, there are over 100 sites in the water- shed-including two EPA Superfund sites (Industri-Plex and wells G and H)-that are now being investigated for the presence of hazardous man-made chemicals (6).
Although many of the chemicals identi- fied at these disposal sites (e.g., gasoline, organic solvents, pesticides, plasticizers) are from contemporary sources, large quantities of toxic elements released by historical tan- ning and chemical manufacturing operations have been discovered. For example, at four sites in Woburn and one in Winchester, tan- ning wastes containing elevated concentra- tions of chromium, arsenic, lead, and other elements have been detected (5). In addition, at the Industri-Plex site, it is estimated that
several tons of arsenic, chromium, and lead were released during the manufacture of arsenic-based pesticides, sulfuric acid, and glues (5,').
The concern that arsenic and chromium residues may be moving off these sites by leaching into groundwater and surface waters has led to several recent investiga- tions. Davis et al. (8) reported that the sedi- ments ofHalls Brook Pond, which is imme- diately downgradient of the Industri-Plex site, contain as much as 3,000 mg/kg As and 1,400 mg/kg Cr [average crustal abun- dances are on the order of 1-10 mg/kg for As and 10-100 mg/kg for Cr (9,10)]. Knox (11) found that many sediments along the Aberjona river, and in particular a riparian wetland area within the wells G and H site boundary (see Fig. 1), contained elevated concentrations of these elements. Spliethoff and Hemond (12) reported that the sedi- ments of Upper Mystic Lake, into which the Aberjona drains, contained the deposi- tional record of As and Cr dating back to the mid-I 800s. Peak concentrations in these sediments were found to be as high as - 1,800 mg/kg As and -6,000 mg/kg Cr.
To date, no work has been done to determine whether residents of this water- shed (population -75,000) have been exposed to elevated levels of As and Cr.
Based on our knowledge ofAs and Cr distri- bution and transport in the watershed, we considered the possibility that water from municipal supply wells G and H may have been contaminated with these elements (13). Wells G and H were used between 1964 and 1979 to supplement supplies to east Woburn, providing as much as 35% of the city's water (14). Although little infor- mation is available on the elemental compo- sition of wells G and H water, the hypothe- sis that the well water contained elevated concentrations of As and Cr-and possibly other elements-was supported by two dis- coveries: as much as 60% of the recharge water for the wells came from the Aberjona river (15), and during the 15 years that the wells were in use, the peak concentrations of As and Cr in the river were estimated, on the basis of lake sediment analysis, to be on the order of 120 and 400 pg/l, respectively (12). This suggested that residents who con- sumed water from wells G and H could have been exposed to as much as 70 pg/l As and 240 pg/l Cr (the drinking water quality standard for As and Cr are currently 50 pg/l and 100 pg/l, respectively).
IfWoburn residents ingested these elevat- ed concentrations of As and Cr, a record of this exposure would be stored in hair that was grown during the period of exposure. Once in the body, As and Cr accumulate in hair, binding strongly to keratin in hair strands (16-18). Retrospective studies performed to determine whether people who had been dead for a long time had experienced acute As exposures [e.g., Napoleon, and the mayor
Address correspondence to W.G. Thilly, Center for Environmental Health Sciences, E18-666, 50 Ames Street, Massachusetts Institute of Technology, Cambridge, MA 02139 USA. The authors are deeply grateful to the residents of Woburn who donated their hair samples for use in our study. We are also indebted to Stephen Boudreault for advice on sample collection, Elfatih Eltahir for advice on statistical analysis, Paul Fricker for assistance with laboratory analysis, Daniel Byrd and Steven Lamm for providing literature refer- ences, and Enda Wang and Konstantin Krapko for translating articles. This research was funded by the National Institute of Environmental Health Sciences Superfund Basic Research Program (P42- ES04675). C.R. and P.T. were supported by fellow- ships from the National Science Foundation. Received 5 March 1997; accepted 10 July 1997.
Volume 105, Number 10, October 1997 * Environmental Health Perspectives