Document ID: EPA-HQ-OPP-2005-0172-0069
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2005-08-29T04:00Z

Modeling
the
Expected
Effect
of
a
Drinking
Water
Pattern
of
Exposure
on
Maximal
Expected
ACHE
Inhibition
Levels
°
Want
to
understand
the
effect
of
brain
inhibition
reversal
half­
life
on
maximum
inhibition
levels
for
a
drinking
water
patern
of
exposure:

 
Breakfast,
lunch,
dinner­­
25%
of
daily
dose
each
 
Drinking
between
meals­­
2
events
delivering
12.5%
of
daily
dose
each
°
Compare
effects
of
BMD10
exposures
to
oxamyl
(
rat
T1/
2
=
0.75
hours)
vs
fermetanate
(
T1/
2
=
5.4
hours)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
1
2
3
4
5
6
Fermetanate
%
ACHE
Inhibition
Oxamyl
%
ACHE
Inhibition
Expected
Time
Pattern
of
Brain
Acetylcholinesterase
Inhibition
for
a
Drinking
Water
Pattern
of
Exposure
to
Fermetanate
(
Inhibition
T1/
2
=
5.4
Hours)
vs
Oxamyl
(
Inhibition
T1/
2
=
0.75
Hours)

Hours
After
Start
of
Exposure
(
Breakfast)

%

Brain
ACHE
Inhibition
Maximum
=
5.89%
Maximum
=
2.65%
Indicated
Relative
Potencies
for
Fermetanate
vs
Oxamyl
for
Maximal
Daily
Inhibition
for
a
Drinking
Water
Pattern
of
Exposure
Half
Life
(
hr)
Maximum
%

Inhibition
for
BMD10
Exposure
Fermetanate
5.4
5.89
Oxamyl
0.75
2.65
Ratio
7.2
2.23