NCD980602163_19961209_Warren County PCB Landfill_SERB C_Risk Assessment - Air Sampling Results-OCR

-11EHNR1EN'v'I R. EPI. TEL:[phone] Dec 09,96 13:27 No.002 P.02
State of North Carolina Department of Environment,
Health and Natural Resources
Division of Epldemiology AWA .--.,
James B. Hunt, Jr., Governor
Jonathon B. Howes, Secretary
Michael Moser, M.D., M.P.H. DEHNR
December 9, 1896
MEMORANDUM
TO: Bill Meyer, Director
Division of Waste Management .3t1<·d ---
THROUGH: Stanley Music, M.D., OTPH (Lond .), Chief , .. •·-z__.,,,:'>
Occupational and Environmental Epidemiology Section
FROM: Luanne K. Williams, Pharm.D., Toxicologist i(,f (;...r-
Medical Evaluation and Risk Assessment Branch
Occupational and Environmental Epidemiology Section
At your request, I have provided a risk assessment following my review of the air
sampling results of the Warren County PCB Landfill reported in the 1983 US EPA study
"Measurement of Fugitive Atmospheric Emissions cf Polychlorinated Biphenyls from Hazardous
Waste Landfills" and the December 3 letter from Dr. Robert G. Lewis, a co-author of the study.
RI.SK ASSESSMENT
1. The ambient air concentrations reported of 11 , 12, 50, and 71 ng/m3 most likely exceed
the actual PCB concentrations present at the site for the following reasons:
(a) the method used is not specific for PCBs but detects all chlorinated compounds
(b) ambient air concentrations were reported to be higher at 98 meters downwind
(50 and 71 ng/m3) than beside the main vent (11 ng/m3) and
(c) aroclor 1260 was the only analyte identified in ambient air even though aroclor
1242 was reported at much higher concentrations in the main vent.
2. It is my opinion that the ambient air concentrations reported are worst •case estimate of
the concentrations that~ be present at the site. Therefore, a worst-case risk
estimate is provided based upon the concentrations reported at the following locations:
L9cations
beside main vent
nearby house
fence line, downwind
P.O. Box 2/687, RolelQh,
(Qonc. det~cted)
11 ng/m3
12 ng/m3
50 and 71 ng/m3
Excess Cancer Bisk
1x10.-6
1x10'6
5 to 7x10--0
An Equal Opportunity Atfirrn ative Action Empie
. '
DEHijRIEN VIR. EPI. TEL:[phone] Dec 09,96 No . 00 2 P Li ' ...... )
Bill Meyer
December 9, 1996
Page Two
If a million people were exposed to the concentrations reported at these three locations
over a lifetime, then one to seven of those individuals could possibly develop cancer as
a result of their exposure to the PCB concentrations reported. This cancer risk is a
worst~case estimate and is in addition to the existing cancer risk rate of 333,333 out of a
million expected cancer cases in a lifetime.
The risk associated with exposure to the concentrations reported at the fenceline does
exceed the acceptable target excess cancer risk of 1x10·11• However, the actual risk at
the site is most likely lower than 7x10..(I because the PCB concentrations present at the
site are most likely lower than reported. The PCB air concentration associated with a
1x10·6 excess cancer risk (target risk) is 10 ng/m3• The fenceline exceeds this level by
7.
3. The concentrations reported near the PCB landfill exceed typical background
concentrations in rural and urban areas. I have attached background concentrations
reported in the February 20 , 1996 ATSDR Tox profile for PCBs. The highest reported
background concentration was 20 ng/m3 in Chicago in 1989-1990.
RECOMMENDATIONS
Contrary to Dr. Lewis' statement in his letter, it is my opinion that it is uncertain as to
whether or not PCBs are present at the site. Because PCBs were detected using a method
that Is not specific for PCBs and since the excess cancer risk estimated at the fenceline
exceeds the acceptable target excess cancer risk of 1 x 1 o-s , it is recommended to collect
additional vent and ambient air samples and analyze for aroclor 1242 and aroclor 1260 using a
more specific method. A carbon filter may also be used as suggested by BFA Environmental
Consultants to minimize PCB emissions from the landfill.
Please call me if you haye any questions at 715-6429.
LKW:lp
Attachments
cc: Dr. Stan Music
Mr. Bill Pate
DEHNR I ENVIP. EPI. TEL:[phone] .
Draft for Public Comment
DEHNR/ENVIR. EPI. TEL:[phone] Dec 09,96 13:;,o N 0 ....
-V Cl. U2 P.05
4... t.. •• :· f'CBs
5 . POTENTIAL FOR HUMAN EXPOSURE
clef.r:lding organisms or, altemaLively, by adding a gcncticully engineered strain lhat combines lhe
activities of mixed cultures (Untcnnan et nl. 1989). Since PCB dl~gradution is a co-mc1abolic
process, the ~1ddi1ion of biphenyl or monot:hlorobiphenyls as grov,,th substrates to i-upply llw
nutritional requirements nnd to induce the catabolic pathway is r~quin:d to s11s1ain the r,rnwth · of the
di::grn<ler population for biodegrad.11ion of Pens in soil (Guilbeaul1 (:I al. 1994; Hickey et al. 1993).
In addition, the presence of $.llrfacc active agents has hce.TJ shown to increase the bioav.-1ilability of
PCBs to the microorganisms. Howt:vcr, e.nriched cultures were unable to hiodcgrade J>CH
congcnt~rs containing five or higher chlorine substitution (Guilbeault et .1I. t 994 ). 1t has lK:en
reported that the mono-, and di-chlorobenzoate. and possibly other higher chlorobenzoates formed
from aerobic dcgrad<1tion of PCRs act as inhibitor.c; towards fu11her degradation of higher chlorinated
PCBs (Guilbeault ct al. 1994). Therefore, the efficie.ncy of PCB degradation is not only (~ontrnlled
by the enzyme substrate selectivity pattern, but also by the metabolite production pat!cm.
5.4 . LEVELS MONITORED OR ESTIMATED IN THE ENVIAONME;NT
5.4.1 Air
Tl1e atmospheric concentrations of PCBs in variou s locations Mt'-given in Table 5-2. The range of
atmo~pheric concentrations of PCBs in urban areas is J. -10 ng/mJ with n mean of 5 ng/m1
(Ei senr(:ich el ul. 1992). The atmospheric concentration~ of PCB~ in two rural areas arc in the rnngl'.
--~--------------
0.2-0.95 ng/m3 with a mean of 0.6 ng/ and in two remote. areas are in the range of OJl.2:oJ 8
nglm' with n mean of <0.1 ng/m' (sec T.iblc 5-2). The range and-;i;.;~--~;,·sphc:ri~--PC.13 --
concentrations in other locations arc as follows : 0.01--0.7 ng /n( and 0. J ng/m '. respectively, in
mari'hl9coastal areas; and 0.2-4.0 ~g7nr and J .o ng/~ respectively, civc~hc (heal Lakes
(Eiscnl'elcn d al.J992). With the available d-a~~~i~--~-;-dif1 :i~1~!~-,~ establi~h · ,he trend in al mosph ,>.ric
Pett-r.rirffr:i1tratio11s over tl~I two decades following ti~<.: r~~;ation of PCB production. This is
because monitoring data indici1ting the level~ of PCBs in air at the same. location over ti, is time
period are. still lacking (levels from one location canno1 be compared with levels from another
because of differing t:mission sources), and lhc recent i-tu<lics (Schreilmudlcr and Dallsclllni1e.r
1994) generally report th<.: atmo~pheric co1H:entrations of the congeners and not lht: tot,il f>CB~ ,.,,.
Aroclors. On the basis of typical atmospheric concc.ntrat ions of PCBs in pre-1980 sm nple:--
(Eisenrcid~ et nl . 1981) and the levels in more recent years (see Table 5-2). it can he cc.ini_:luded llh :
PCB concentrations in air rnay have. shown a sligt11ly decreasing tn:n,I frona 1h c prc.-1980 1n po~t-
DEHNR I ENVIR. EPI.
a TEL:[phone] Dec 09,96
' .,,
-... -
5. ron:NllAL H)R HUMAN EXf-'OSUnE
TABLE 5~2. Atmospheric Concentrations of Polychlorinated Biphenyls
·---·· ... --, ----· ·--·------... -
ConcentrationN
Location Year (ng/m~) Reference ----·--______ , .. _____
Boston, MA 1978 7.1 Bidleman 1981
Columbia, SC 1978 4.4 Bidleman 1981
Columbia, SC 1985 2.3 Foreman and
Bidloman 1987
College Station, TX 1979-1980 0.29 Atlas and Giam
0.11-0.48 1987
Newport News, VA 1988 0.39 Knap and Binkley
(0.185-0. 794) 1991
Bloomington, IN 1986-1988 Summer: 1.74-3.84to Hermanson and
Winter: 0.31-0.62 Hites 1989
Chicago, IL 1989-1990 13.5 Holsen et al. 1991
(7 .55-20.26)
.A.dirondack, NY 1985 0.95 ~(nap and Binkley
(0.339-1 .359) 1991
Chesapeake Bay 1990-1991 0.21 Leister and Baker
(0.017-0.508) 1994
Lake Superior 1986 1.25 Baker and
Eisenreich , 990
Ru ral Ontario, Canada 1988-1989 0.2 Hoff et al. 1992
(0.55-0.823)
Antarctica 1981-1982 (0.02-0.18) Tanabe et al. 1983
Arctic 1986-1987 0.02 Baker and
Eisenreich , 990
"Values are given as mean concentrations. The ranges are given in parentheses.
vvalues at three different sites.