Transcript daq.state.nc.us

North Carolina Eastern Regional
Mercury Study: Results
Michelle Woolfolk
NC Division of Water Quality
Presented April 19, 2004 at the CSSA Meeting
NC Eastern Regional Mercury Study
•
•
Funded by USEPA grant (104(b)(3))
Goals
1. Evaluate levels of ambient mercury in surface water
systems using low level techniques (Method 1631)
2. Estimate site-specific total mercury:methyl mercury
translators to evaluate water quality criteria
3. Estimate site-specific water to fish bioaccumulation
factors
4. Evaluate potential mercury loads from WWTPs
•
Referred to hereafter as the ERMS
NC Eastern Regional Mercury Study Sites
Ch
ow
an
Riv
er
Eno River
#
Tar Riv er
w
Ha
#
#
#
Phelps Lake
#
r
ve
Ri
Abbotts Creek
Cashie River Kendricks Creek
pR
Dee
iver
Contentnea Creek
#
River
Neuse
N
e
Pe
e
De
r
ve
Ri
Ledbetter Lake
W
#
South River
# Black River
r
ve
Ri
ar
Fe
#
pe
Ca
Lumber River
S
#
Lake Waccamaw
#
Waccamaw River
#
Waccamaw River
#
80
DWQ, 1/17/2003
0
E
80 Miles
Major hydrography
River basins
BROAD
CAPE FEAR
CATAWBA
CHOW AN
FRENCH BROAD
HIWASSEE
LITTLE TENNESSEE
LUMBER
NEUSE
NEW
PASQUOTANK
ROANOKE
SAVANNAH
TAR-PAMLICO
WATAUGA
WHITE OAK
YADKIN
Ambient Surface Water Total Hg
Figure 4-1a. ERMS: Total Mercury Histogram
No. of
observations
46
Geometric
mean (ng/L)
Median (ng/L)
4.49
Range of
concentrations
1.06 – 28.6
4.1
Goal 1: Ambient mercury levels
Frequency
30
25
20
15
10
5
0
o 5 to 1 0 to 15 to 20 to 30 to 40
0t
5
10
15
20
30
Total Hg conc., ng/L
Standard exceeded in 11 % of
samples.
0
>4
Ambient Surface Water Total MeHg
No. of
observations
Geometric
mean (ng/L)
Median (ng/L)
Range of
concentrations
48
0.32
0.241
0.065 – 4.04
Goal 1: Ambient mercury levels
Frequency
ERMS: Total Methylm ercury Histogram - XX
30
25
20
15
10
5
0
.3
.1
0.6
0.9
1.2
1.5
1.8
2.1
o 0 3 to 6 to 9 to 2 to 5 to 8 to
>2
t
0
0.
0.
0.
1.
1.
1.
Total Hg conc., ng/L
Ambient sediment Total Hg
No. of
observations
24
Geometric
mean (ng/g)
Median (ng/g)
20.22
Range of
concentrations
1.52 – 322.3
Frequency
Figure 4-?. ERMS: Total Mercury in Sedim ent
10
8
6
4
2
0
5
0
5
0
5
0
5
5
o3
o4
o 6 to 7
o 9 to 10 > 10
o1
t
t
t
t
t
5
0
5
0
5
0
1
3
4
6
7
90
28.22
Goal 1: Ambient mercury levels
Total Hg conc., ng/g
Ambient sediment Total MeHg
No. of
observations
24
Geometric
mean (ng/g)
Median (ng/g)
0.471
Range of
concentrations
0.014 – 3.867
Frequency
ERMS: Total Monom ethyl Mercury in Sedim ent
12
10
8
6
4
2
0
.2
0.4 o 0.6 o 0.8 o 1.0 o 1.2 o 1.4
1.4
o 0 2 to
>
t
t
t
t
t
t
0
0.
0.4
0.6
0.8
1.0
1.2
0.214
Goal 1: Ambient mercury levels
Total MeHg conc., ng/g
Ambient Hg residue: piscivorous fish
Figure 4-?. ERMS: Mercury levels in Piscivorous Fish
Residue, mg/kg
2.5
2
1.5
1
Black crappie
0.5
0
Bow fin (n=6)
25%ile
Chain Pickerel
(n=9)
Median
Largemouth
Bass (n=71)
75%ile
Goal 1: Ambient mercury levels
Yellow Perch
(n=15)
Maximum
Black Crappie Flathead catfish
(n=6)
(n=3)
Minimum
DHHS Action Level
Ambient Hg residue: Omnivores and
Insectivores
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
Creek chubsucker
(n=3)
25%ile
Median
White catfish (n=3)
75%ile
Minimum
Brow n bullhead (n=7)
Maximum
Channel catfish (n=6)
White catfish
DHHS Action Level
Figure 4-?. ERMS: Mercury Levels in Insectivorous Fish
1
Residue, mg/kg
Residue, mg/kg
Figure 4-?. ERMS: Mercury Residue in Omnivorous Fish
Spotted sucker
0.8
0.6
0.4
0.2
0
Redbreast
sunfish (n=9)
Pumpkinseed
(n=4)
Bluegill sunfish Redear sunfish Spotted sucker Silver redhorse
(n=18)
(n=24)
(n=21)
(n=3)
25%ile
Median
75%ile
Minimum
Maximum
DHHS Action Level
Bioaccumulation factors
• Bioaccumulation is the uptake and retention of a
chemical by a living organism as a result of either
intake of food, drinking water, air or direct contact.
(EPA 1994b)
• A bioaccumulation factor is defined as :
BAF =
Residue
C(d)
where
Residue = concentration in wet tissue, mg/kg
C(d) = concentration of chemical dissolved in H2O, mg/L
Goal 3: Bioaccumulation
Bioaccumulation factors, cont.
• Can be species specific, size specific, or
trophic level specific
– Species specific: e.g., largemouth bass, black
crappie, bluegill sunfish, etc.
– Size specific: e.g., largemouth bass of length
40 cm
– Trophic level specific: e.g., all of trophic level
3
Goal 3: Bioaccumulation
Largemouth bass bioaccumulation
• One of three species with a regional
advisory by DHHS
• Caught and analyzed at every site in ERMS
(makes site-to-site comparison possible)
• Calculate BAFs to all fish caught at a site
and to a “normalized” 40-cm bass
• Allow variability in exposure concentration
Goal 3: Bioaccumulation
Largemouth bass BAFs
Figure 5-?. ERMS Range of Bioaccumulation Factors
(All largemouth bass)
BAF (mg-L/kg-ng)
100
10
1
0.1
ts
ot
b
b
A
C
r
)
=6
n
(
B
ck
la
R
3)
=
(n
C
h
as
ie
C
R
te
on
=8
(n
)
a
ne
t
n
n
C
r(
1st quartile
Goal 3: Bioaccumulation
0
=1
)
o
En
R
=8
(n
)
4)
=
n
C
r(
k
rL
4)
=
n
(
ks
te
m
ic
et
r
ca
b
d
c
d
n
a
Le
W
Ke
Lk
aw
Median
3rd quartile
(n
0)
1
=
b
1)
=
n
R
er
m
Lu
(
lp
he
P
""
s
ke
La
(n
0
=1
)
=1
(n
)
R
R
h
t
w
u
a
m
So
ca
c
a
W
Lower CL
6
n=
)
(
Upper CL
ac
k
ts
Cr
R
Ca
sh
Co
ie
nt
R
en
tn
ea
Cr
En
o
Ke
R
nd
r ic
ks
Le
Cr
db
et
te
Lk
rL
W
k
ac
ca
m
aw
Lu
m
be
rR
Ph
el
ps
La
ke
So
ut
W
h
ac
R
ca
m
aw
R
Bl
Ab
bo
t
BAF (mg-L/kg-ng)
1
0.1
Goal 3: Bioaccumulation
Insufficient data
Insufficient data
40-cm Largemouth bass BAFs
Figure 5-?. ERMS: Range of Bioaccumulation Factors
(Reference fish: 40-cm LMB)
100
10
What is the significance of BAFs?
• We use the BAFs to calculate the allowable
water concentrations of MeHg(d) and
ultimately Hg(t).
• Required to implement the AWQC for
methylmercury
Goal 3: Bioaccumulation
Target water column levels
• Evaluate human health endpoint, not
wildlife
• Only evaluate to DHHS criteria
• Site-specific water column translators (i.e.,
MeHg(d)/MeHg(t) and MeHg(t)/Hg(t))
[less confidence in relationships between
MeHg(d) and Hg(t)]
Goal 3a: Target water levels
Target water column levels
Concentration, ng/L
Figure 5-?. ERMS: Range of Target Total Mercury Levels
(All largemouth bass)
100
10
1
0.1
A
ts
ot
b
b
C
r
B
ck
la
R
e
hi
C
as
C
1st quartile
Median
R
te
on
a
ne
t
n
C
r
o
En
R
K
3rd quartile
Goal 3a: Target water levels
i
dr
n
e
s
ck
C
r
d
Le
rL
tt e
be
NC WQS
Lk
k
aw
am
c
ac
W
r
be
m
Lu
Low er CL
R
p
el
h
P
s
ke
a
L
th
ou
S
Upper CL
R
aw
R
m
ca
c
a
W
Series7
Target water column levels, cont.
Figure 5-?. ERMS: Range of Target Total Mercury Levels
(Reference fish: 40-cm LMB)
Central (GM)
NC WQS
Goal 3a: Target water levels
75%ile ERMS
Low er CL
W
R
ac
ca
m
aw
R
R
Ke
nd
ri c
ks
C
Le
r
db
et
te
rL
Lk
k
W
ac
ca
m
aw
Lu
m
be
rR
Ph
el
ps
La
ke
En
o
R
on
te
nt
ne
a
C
r
C
C
as
hi
e
R
Bl
ac
k
Ab
bo
tts
C
r
0.1
So
ut
h
1
Insufficient data
10
Insufficient data
Concentration, ng/L
100
Upper CL
And now for the big picture…
Houston, we have a problem ...
Total Hg conc, ng/L
1000.0
100.0
Allowable Hg conc.
10.0
1.0
0.1
Lk Waccamaw
Waccamaw R
1st quartile
ERMS effluent
Median
3rd quartile
Waccamaw MDN
Rainwater
Photo-toon by R. Johnson
Questions?
Michelle Woolfolk
Div. of Water Quality, Modeling Unit
(919) 733-5083 ext. 505
[email protected]
Connie Brower
Div. Of Water Quality, Standards Unit
(919) 733-5083 ext. 572
[email protected]