Point
Source
Nutrient
Loadings
in
the
Mississippi
River
System
March
5,
2003
The
EPA
conducted
an
analysis
of
point
source
nutrient
loadings
in
the
Mississippi
River
System.

Purpose:
The
Analysis
of
Point
Source
Nutrient
Loadings
in
the
Mississippi
River
System
was
prepared
to
support
the
White
House
Committee
on
Environment
and
Natural
Resources'
(
CENR)
Gulf
of
Mexico
Hypoxia
Working
Group
efforts
to
assess
the
causes
and
consequences
of
hypoxia
in
the
Gulf
of
Mexico.

Results:
The
study
results
provide
estimated
annual
nutrient
discharges
for
total
nitrogen
and
phosphorus
for
approximately
11,500
point
source
facilities
within
the
Mississippi
River
Basin
system.
The
total
annual
nutrient
loads
from
all
point
sources
for
total
nitrogen
and
phosphorus
were
estimated
to
be
643
million
pounds
and
133
million
pounds
respectively.
Data
are
contained
in
three
Excel
95
spreadsheets
which
can
be
accessed
from
the
EPA
web
page
at
http://
www.
epa.
gov/
msbasin/
loadings.
htm.
The
tables
below
indicate
the
chief
contributors
of
nutrients
to
the
Mississippi
River
System
by
industry,
from
a
total
of
390
possible
industries
evaluated.
Of
the
point
sources,
municipal
discharges
accounted
for
70%
of
the
total
nitrogen
and
51%
of
the
total
phosphorus.

Table
1
below
identifies
the
top
21
contributors
of
total
nitrogen
(
contributing
95%
of
the
total
point
source
load),
Table
2
identifies
the
top
41
contributors
of
total
phosphorus
(
contributing
95%
of
the
total
point
source
load).
Table
3
illustrates
that
19
of
the
top
21
nitrogen
contributors
are
also
in
the
top
31
phosphorus
contributors.

Methodology:
Two
previous
studies
that
addressed
sources
of
nutrients
in
the
Mississippi
River
system.
The
first
is
an
EPA
report
prepared
by
Tetra
Tech
"
Documentation
of
Phase
I
and
Phase
II
Activities
in
Support
of
Point
Source
Nutrient
Loading
Analysis
in
the
Mississippi
River
System
(
7/
98),
available
at
http://
www.
epa.
gov/
msbasin/
phases.
htm,
from
which
these
results
were
developed.
It
is
supplemented
by
the
protocol
used
to
develop
the
final
results,
which
can
be
found
at
http://
www.
epa.
gov/
msbasin/
protocol.
htm.
The
second
report
is
the
U.
S.
Department
of
Commerce's
NOAA
report
"
Flux
and
Sources
of
Nutrients
in
the
Mississippi­
Atchafalaya
River
Basin
­
Topic
3
Report
for
the
Integrated
Assessment
on
Hyposia
in
the
Gulf
of
Mexico
(
5/
99).
The
NOAA
report
notes
that
nonpoint
sources
contribute
about
90
percent
of
the
total
nitrogen
an
phosphorus
entering
the
Mississippi
River
System,
with
agricultural
activities
being
the
largest
contributors
of
both
of
these
nutrients.

Contact:
Mary
Belefski
(
202)
566­
1212
Short­
term
Followup:
Contact
the
EPA
Task
Force
responsible
for
the
Action
Plan
for
Reducing,
Mitigating,
and
Controlling
Hypoxia
in
the
Northern
Gulf
of
Mexico
to
determine
the
status
their
short­
term
goals.
These
goals
include
monitoring
efforts,
studies
and
strategies
for
nutrient
loading
reduction,
additional
efforts
to
identify
significant
point
source
dischargers
of
nutrients
and
reducing
their
loads,
and
potential
voluntary
actions.

Long­
term
Followup:
Collect
all
available
data
generated
from
the
short­
term
goals
to
support
the
planning
process.

Table
1:
Top
Contributors
of
Total
Nitrogen
(
Accounting
for
95%
of
total
load)

Rank
Sum
of
BEST
ESTIMATE
Total
Nitrogen
ANNUAL
LOAD
(
lbs/
YR)
No.
Facility
Type
Total
Of
390
1
Municipal
449,854,637
70%
2
Plastics
materials
&
resins
28,648,686
4%
3
Refuse
systems
14,801,664
2%
4
nitrogenous
fertilizers
14,146,203
2%
5
Primary
aluminum
13,494,456
2%
6Wet
corn
milling
11,611,176
2%
7
Blast
furnaces
&
steel
mills
8,834,989
1%
8
Cyclic
crudes
&
Intermediates
8,423,954
1%
9
Industrial
Inorganic
chemicals,
NEC
6,995,119
1%
10
Meat
packing
plants
6,766,578
1%
11
Petroleum
refining
6,625,177
1%
12
Beef
cattle
feedlots
5,914,201
1%
13
Paper
mills
5,747,612
1%
14
Pulp
mills
5,625,299
1%
15
Cellulosic
manmade
fibers
4,143,917
1%
16
national
security
3,484,848
1%
17
Paints
and
allied
products
3,051,224
0%
18
Cold
finishing
of
steel
shapes
2,617,604
0%
19
Primary
nonferrous
metals,
NEC
2,207,537
0%
20
Poultry
slaughtering
&
processing
1,997,804
0%
21
Petroleum
bulk
stat.
&
term.
1,874,870
0%
Grand
Total
641,938,881
95%
Table
2:
Top
Contributors
of
Total
Phosphorus
(
Accounting
for
95%
of
total
load)

Rank
Sum
of
BEST
ESTIMATE
Total
Phosphorus
ANNUAL
LOAD
(
lbs/
yr)%
No.
Facility
Type
Total
Out
of
390
1
Municipal
67,457,250
51%
2
Beef
cattle
feedlots
8,508,149
6%
3
Wet
corn
milling
5,877,623
4%
4
Petroleum
refining
3,910,332
3%
5
Blast
furnaces
&
steel
mills
3,859,608
3%
6
Paper
mills
3,821,188
3%
7
Plastics
materials
&
resins
3,362,204
3%
8
Industrial
Inorganic
chemicals,
NEC
2,734,463
2%
9
Pulp
mills
2,396,654
2%
10
national
security
2,118,710
2%
11
Refuse
systems
1,681,738
1%
12
Chemical
preparations,
NEC
1,418,008
1%
13
Primary
aluminum
1,401,960
1%
14
Paperboard
mills
1,363,927
1%
15
Petroleum
bulk
stat.
&
term.
1,172,099
1%
16
Distilled
and
blended
liquors
1,168,482
1%
17
Poultry
slaughtering
&
processing
1,081,226
1%
18
nitrogenous
fertilizers
917,180
1%
19
Regulation
admin.
of
transport
869,500
1%
20
Admin.
of
general
economic
pgm
788,758
1%
21
Dairy
farms
762,535
1%
22
Electrometallurgical
products
732,331
1%
85%
23
Airports,
flying
fields,
&
ser
666,384
1%
24
natural
gas
transmission
663,686
0.5%
25
Cellulosic
manmade
fibers
640,734
0.5%
26
Meat
packing
plants
581,886
0.4%
27
Metal
coating
&
allied
services
519,220
0.4%
28
Alkalies
and
chlorine
506,883
0.4%
29
nonferrous
rolling
&
drawing,
NEC
449,480
0.3%
30
Prepared
feeds,
NEC
433,824
0.3%
31
Cyclic
crudes
&
Intermediates
431,858
0.3%
32
Cereal
breakfast
foods
425,272
0.3%
90%
33
Mechanical
rubber
goods
420,902
0.3%
34
Gray
and
ductile
iron
foundries
420,380
0.3%
35
Explosives
377,131
0.3%
36
Cheese,
natural
&
processed
369,782
0.3%
37
INorganic
pigments
368,019
0.3%
38
Soybean
oil
mills
362,551
0.3%
39
nonresidential
buildINg
oprtrs
330,757
0.2%
40
PaINts
and
allied
products
310,493
0.2%
41
Mobile
home
site
operators
293,585
0.2%
Grand
Total
132,921,302
95%
95%
Table
3:
Top
Contributors
of
Total
Nutrients
(
Appearing
on
Both
Previous
Tables)

Sum
of
BEST
ESTIMATE
ANNUAL
LOAD
(
lbs/
YR)
Facility
Type
Total
TN
Out
of
390
Rank
No
Total
TP
Out
of
390
No
Municipal
449,854,637
70%
1
67,457,250
51%
1
Plastics
materials
&
resins
28,648,686
4%
2
3,362,204
3%
7
Refuse
systems
14,801,664
2%
3
1,681,738
1%
11
nitrogenous
fertilizers
14,146,203
2%
4
917,180
1%
18
Primary
aluminum
13,494,456
2%
5
1,401,960
1%
13
Wet
corn
milling
11,611,176
2%
6
5,877,623
4%
3
Blast
furnaces
&
steel
mills
8,834,989
1%
7
3,859,608
3%
5
Cyclic
crudes
&
Intermediates
8,423,954
1%
8
431,858
0.3%
31
Industrial
Inorganic
chemicals,
NEC
6,995,119
1%
9
2,734,463
2%
8
Meat
packing
plants
6,766,578
1%
10
581,886
0.4%
26
Petroleum
refining
6,625,177
1%
11
3,910,332
3%
4
Beef
cattle
feedlots
5,914,201
1%
12
8,508,149
6%
2
Paper
mills
5,747,612
1%
13
3,821,188
3%
6
Pulp
mills
5,625,299
1%
14
2,396,654
2%
9
Cellulosic
manmade
fibers
4,143,917
1%
15
640,734
0.5%
25
national
security
3,484,848
1%
16
2,118,710
2%
10
Paints
and
allied
products
3,051,224
0.5%
17
310,493
0.2%
40
Cold
finishing
of
steel
shapes
2,617,604
0.4%
18
Primary
nonferrous
metals,
NEC
2,207,537
0.3%
19
Poultry
slaughtering
&
processing
1,997,804
0.3%
20
1,081,226
1%
17
Petroleum
bulk
stat.
&
term.
1,874,870
0.3%
21
1,172,099
1%
15
Grand
Total
641,938,881
95%
132,921,302
84%
