Supplemental Data for
Modeled Methylmercury Exposure and Risk from Rice Consumption
for Vulnerable Populations in a Traditional Fish Eating Area in China
Yindong Tong† ,‡, Langbo Ou†, Long Chen†, Huanhuan Wang†, Cen Chen§, Xuejun
Wang†*, Wei Zhang||**, Qiguang Wang#
†
Ministry of Education Laboratory of Earth Surface Processes//College of Urban and
Environmental Sciences, Peking University, Beijing 100871, China
‡
School of Environmental Science and Engineering, Tianjin University, Tianjin,
300072, China
§
Tianjin Institute of Metrological Supervision and Testing, Tianjin, 300192, China
||
School of Environment and Natural Resources, Renmin University of China, Beijing
100872, China
#
China Meteorological Administration Training Center, CMA, Beijing 100081, China
Sampling locations, characteristics of the pregnant women, definitions of Z and D
values, definition of symbols used in the model, input parameters and equations used
in the food web model, aquivalence factors for consumption and respiration, MeHg
fluxes for pregnant women under different scenarios and contribution of MeHg from
rice and fish.
S1
Figures
Figure S1. Sampling locations of this study
S2
Tables
Table S1. Definitions of Z and D Values
Definitions of Z and D Values
Z values
Water
ZW = 1.00
Assumed
Lipid
ZO = KowZW
KOW = octanol water partition coefficient
Nonlipid organic matter
ZN = KB.ρBZW
KB = bioconcentration factor (L/kg)
ρB = organism density(kg/L)
Fish/organism
ZF = FLZO + FNZN+ FWZW
Food
ZA = ZF
FL = lipid fraction
FN = nonlipid organic fraction
FW = water fraction
ZA = assumed to be the Z value of its prey
D values
Chemical exchange
GW = gill ventilation rate (m3/h)
DW = GWEWZW
through respiration
EW = efficiency of chemical transfer across
gills
Net chemical intake
D A = E DG D Z A
ED = gut absorption efficiency
GD = food ingestion rate (m3/h)
from food
Growth dilution
DG = VFZFkG
kG = growth rate (/h)
VF = volume of the organism (m3)
Chemical loss by
DE = DA/LB
LB = limiting biomagnification factor
DM = VFZFkM
kM = metabolic rate (/h)
excretion
Chemical loss by
metabolism
S3
Table S2. Definition of the symbols used in the model1
Parameter
Unit
Definition
QW, QF, QA
mol/m3
DA, DW, DE, DG, DM
m3/h
ZW, ZN, ZO, ZF, ZA
—
Aquivalence values of water, the organism, and food,
respectively
Mass-transport parameters for food intake, contaminant
exchange with water, excretion, growth dilution, and loss by
metabolism, respectively
Aquivalence capacities of water, nonlipid organic matter,
lipid, the organism, and food, respectively
G D, G W
MT
EOX
EW
ED
m3/h
Food ingestion rate; gill ventilation rate/drinking
mg/h
—
—
—
Total energy biotransformation
Maximum efficiency of oxygen transfer across the gills
COX
WB
kM
kG
Q
T
tH
mg/m3
g
/h
g/day
none
°C
d
L/kg
%
%
%
—
KB
FL
FW
FN
KOW
Efficiency of chemical transfer across gills
Efficiency of contaminant transfer between the gut contents
and the organism
Dissolved oxygen concentration in water
Weight of the organism
Metabolic rate
Growth rate
Limiting biomagnification factor
Water temperature
Half-life of the chemical
Bioconcentration factor
Lipid fraction
Water fraction
Nonlipid organic fraction
Octanol water partition coefficient
S4
Table S3. Input parameters and equations used in the food web modela
GW
EOX
Log(MT)
COX
GD
ED
WB
kG
kM
River shrimp
Common carp
Crucian carp
Silver carp
Pregnant women
Infants
Reference
MT.(EOX.COX)−1
0.65
0.67log(WB × 1000) +
0.017T − 0.77
(14.45 − 0.413T +
0.00556T2) × 1000−1
9.2 × 10−7 WB
0.85exp(0.06T)
0.9
0.7
0.01
0.693 × (24×tH)−1
MT.(EOX.COX)−1
0.65
Same as river
shrimp
Same as river
shrimp
Same as river
shrimp
0.9
850
1.58
Same as river
shrimp
3
20
126
1.32×106
0.12
5%
75%
Same as river
shrimp
1.7
MT.(EOX.COX)−1
0.65
Same as river
shrimp
Same as river
shrimp
Same as river
shrimp
0.9
40
0.11
Same as river
shrimp
3
20
126
1.32×106
0.12
5%
75%
Same as river
shrimp
1.7
MT.(EOX.COX)−1
0.65
Same as river
shrimp
Same as river
shrimp
Same as river
shrimp
0.9
800
1.20
Same as river
shrimp
3
—
126
1.32×106
0.12
5%
75%
Same as river
shrimp
1.7
—
—
—
—
—
—
2
3
4
—
—
5
4.2 × 10−6 (fish);
1.40 × 10−5 (Rice)
0.9
71000
44.73
Same as river
shrimp
30
—
~50
2.5×107
—
14%
65%
Same as river
shrimp
1.7
~2.92 × 10−5
4–10
0.9
9200
27.85
Same as
river shrimp
30
—
~50
2.5×107
—
14%
65%
Same as
river shrimp
1.7
11
Measured
9,12–14
15
T
tH
KB
EW
FL
FW
FN
3
20
126
1.32 × 106
0.12
4%
80%
100% − FL − FW
KOW
1.7
Q
aAs
15
Assumed
11,16
16a
5
Assumed
Measuredb
Calculated
16
the top predator, the bioconcentration factor (KB) in humans was assumed to be equal to that of herring gull, which was 2.5 × 107 L/Kg in a prior study.7
S5
b
The water content of the human body was assumed.
S6
Table S4. Characteristics of the pregnant women in this study
Characteristic
Mean (range)
Characteristic
Mean (range)
Age (years)
28.63 (22–44)
Gestational age (weeks)
39.16 (37.00–41.00)
Height (m)
1.64 (1.58–1.72)
Living years (years)
15.2 (3–32)
Body weight (kg)
68.88 (46–83)
Smoking during pregnancy
None
Gestational BMI (kg/m2)
25.53 (19.20–33.13)
Alcohol consumption during
pregnancy
None
Percent
of
women
with
16.6%
dental fillings
BMI, body mass index.
S7
Table S5. Aquivalence factors for consumption and respiration in the food web model
Consumption (A)*
Respiration from water (W)
Common carp
6.94 × 10−2
6.59 × 10−3
Crucian carp
2.41 × 10−1
4.47 × 10−2
Silver carp
1.74 × 10−1
8.37 × 10−3
*The aquivalence factor for consumption was based on plankton.
S8
Table S6. MeHg fluxes for pregnant women under different scenarios (ng/day)
Ingestion
Metabolism
Egestion
Growth dilution
Scenario I
1529.1
1446.6
0.28
82.2
Scenario II
1643.7
1555.0
0.30
88.4
Scenario III
2273.8
2151.2
0.41
122.2
Scenario III
4333.1
4099.3
0.79
232.9
S9
Tables S7. Contributions of MeHg from rice and fish
MeHg contribution
from fish
MeHg contribution
from rice
Scenario I
Scenario II
Scenario III
Scenario IV
100%
93%
67%
35%
0
7%
33%
65%
S10
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