Table 3-1 Levels of Significant Exposure to Barium - Oral
(continued)
Exposure/
LOAEL
Duration/
a
Key to Species
Frequency
NOAEL
Less Serious
Serious
Reference
Figure (Strain)
(Route)
System
(mg/kg/day)
(mg/kg/day)
(mg/kg/day)
Chemical Form
Neurological
53
Rat
(Sprague-
Dawley)
68 wk
(W)
15 M
McCauley et al. 1985
NR
54
Rat
(Fischer- 344)
2 yr
(W)
60 M
NTP 1994
Barium chloride
55
Mouse
(B6C3F1)
Reproductive
56
Rat
(Sprague-
Dawley)
2 yr
(W)
68 wk
(W)
160 M
15 M
NTP 1994
Barium chloride
McCauley et al. 1985
NR
57
Rat
2 yr
c
60 M
NTP 1994
(Fischer- 344) (W)
Barium chloride
75 F
58
Mouse
2 yr
c
160 M
NTP 1994
(B6C3F1)
(W)
Barium chloride
200 F
Comments
Histological
examination of brain.
Histological
examination of brain.
Histological
examination of brain.
Histological
examination of
reproductive tissues.
Histological
examination of
reproductive tissues.
Histological
examination of
reproductive tissues.
BARIUM AND BARIUM COMPOUNDS
3. HEALTH EFFECTS
42
a The number corresponds to entries in Figure 3-1.
b Used to derive an intermediate duration oral minimal risk level (MRL) of 0.2 mg barium/kg/day; dose divided by an uncertainty factor of 100 (10 for extrapolation from animals to
humans and 10 for human variability) and modifying factor of 3 to account for database deficiencies.
c Differences in levels of health effects and cancer effects between male and females are not indicated in Figure 3-1. Where such differences exist, only the levels of effect for the
most sensitive gender are presented.
d The chronic-duration oral MRL of 0.2 mg barium/kg/day was calculated using benchmark dose analysis. The BMDL5 of 61 mg barium/kg/day was divided by an uncertainty factor
of 100 (10 to account for extrapolation from animals to humans and 10 for human variability) and modifying factor of 3 to account for database deficiencies.
Cardio = cardiovascular; d = day; F = female; Gastro = gastrointestinal; (GW) = gavage in water; Hemato = hematological; LD50 = lethal dose, 50% kill; M = male; mo = month;
Musc/skel = musculoskeletal; NS = not specified; NR = not reported; Resp = respiratory; (W) = drinking water; wk = week; x = time(s); yr = year
Death
Respiratory
Cardiovascular
Gastrointestinal
Hematological
Hepatic
Renal
Ocular
Body Weight Other
Immuno/Lymphor
Neurological
1000
Figure 3-1 Levels of Significant Exposure to Barium - Oral
Acute (≤14 days)
Systemic
BARIUM AND BARIUM COMPOUNDS
mg/kg/day
2r
3r
1r
4r
5r
4r
5r
4r
5r
4r
5r
4r
5r
4r
5r
4r
5r
4r
5r
5r
6r
7r
3r
100
5r
5r
5r
5r
5r
5r
10
3.
HEALTH EFFECTS
c-Cat
d-Dog
r-Rat
p-Pig
q-Cow
-Humans
k-Monkey
m-Mouse
h-Rabbit
a-Sheep
f-Ferret
j-Pigeon
e-Gerbil
s-Hamster
g-Guinea Pig
n-Mink
o-Other
Cancer Effect Level-Animals
LOAEL, More Serious-Animals
LOAEL, Less Serious-Animals
NOAEL - Animals
Cancer Effect Level-Humans
LOAEL, More Serious-Humans
LOAEL, Less Serious-Humans
NOAEL - Humans
LD50/LC50
for effects
other than
Cancer
Minimal Risk Level
43
Reproductive
Figure 3-1 Levels of Significant Exposure to Barium - Oral
(Continued)
Acute (≤14 days)
mg/kg/day
1000
8r
9r
9r
100
10
BARIUM AND BARIUM COMPOUNDS
3. HEALTH EFFECTS
c-Cat
d-Dog
r-Rat
p-Pig
q-Cow
-Humans
k-Monkey
m-Mouse
h-Rabbit
a-Sheep
f-Ferret
j-Pigeon
e-Gerbil
s-Hamster
g-Guinea Pig
n-Mink
o-Other
Cancer Effect Level-Animals
LOAEL, More Serious-Animals
LOAEL, Less Serious-Animals
NOAEL - Animals
Cancer Effect Level-Humans
LOAEL, More Serious-Humans
LOAEL, Less Serious-Humans
NOAEL - Humans
LD50/LC50
Minimal Risk Level
for effects
other than
Cancer
44