The document summarizes the history of pollution in Lake Erie and efforts to reduce phosphorus levels. It identifies key causes of pollution over time, including sediment, sewage, overfishing, chemicals, nutrients, and invasive species. Sources of phosphorus include land use, discharges, resource exploitation, and invasive species introduction. Agriculture is identified as a key nonpoint source of phosphorus, though levels of inputs from fertilizer, manure, and biosolids have decreased. Recommendations focus on improving nutrient management practices in agriculture to reduce dissolved reactive phosphorus runoff. Ongoing monitoring and research aim to evaluate the impacts of changes and ensure phosphorus reductions are achieved.

1. Julie Letterhos
Ohio Environmental Protection Agency
March 12, 2010

2. Lake Erie Pollution History
Causes have varied over the years
Sediment
Raw sewage/disease
Overfishing
Chemical contamination
Nutrients
Exotic species
Loss of habitat

3. Sources
Land Use
Discharges
Exploitation of the resource
Introduction of Invasive Species

4. Lake Erie Cross Section
4

5. Nutrients
Phosphorus identified as the limiting nutrient
Lake Erie Wastewater Management Study (LEWMS)
Pollution from Land Use Activities Reference Group
(PLUARG)
Great Lakes Water Quality Agreement
Clean Water Act
Phosphorus Reduction Strategies

6. Phosphorus Bioavailability
Total Phosphorus varies with source
Dissolved Reactive Phosphorus
~100% bioavailable
Particulate Phosphorus
10 - 30% bioavailable

7. Point vs. Nonpoint Source
Typically, TP from point sources 85% DRP and is
considered to be 100% bioavailable
TP from nonpoint sources, or the tributary load, was
largely particulate and considered about 30%
bioavailable, but that seems to be changing

8. Decreases in Phosphorus Loads

9. Lake Erie
Algal Bloom
Blue-green
algal blooms,
once common
in the 1960s,
began to return
in the mid-
1990s.

11. Cladophora

12. Lyngbya wollei
Benthic mats become buoyant and float to surface
T. Fisher

13. A Comparison…
1960 - 1970s 1990s – Today
Cladophora Cladophora
Blue-green algae Blue-green algae
Anabaena Microcystis -
Aphanizomenon dominant
Microcystis (present Lyngbya wollei first
appeared in 2006
but not dominant)

14. Maumee River, Flow Weighted Mean
Concentration, Dissolved Reactive Phosphorus
75-94 95-08 Linear (75-94) Linear (95-08)
0.120
0.100
DRP, FWMC, mg/L
0.080
0.060
0.040
0.020
0.000
1975 1980 1985 1990 1995 2000 2005 2010
Water Year

15. Maumee River, Annual Loading,
Dissolved Reactive Phosphorus, 1975-2008
900
800
Phosphorus, metric tons
700
Dissolved Reactive
600
500
400
300
200
100
0
1975 1980 1985 1990 1995 2000 2005
Water Year

16. Ohio Lake Erie Phosphorus Task Force Members
State program personnel from OEPA, ODNR and ODA
Academia/Researchers
Agricultural agencies and organizations at the federal,
state and local level (NRCS, ARS, OSU Extension,
Ohio Farm Bureau, Conservation Action Program)
USEPA-Great Lakes National Program Office
USGS
Wastewater Treatment Plant personnel
Ohio Lake Erie Office
Ohio Fractured Flow Work Group

17. Task Force Goals (Ohio Focus)
Identify and evaluate all potential sources
Identify changes since 1995
Examine aspects of agriculture that might
influence increase in DRP loads
Review relationship between increased DRP and
the returning eutrophication in the lake
Consider dreissenids and internal cycling
Identify research and monitoring needs
Make short and long term recommendations

18. P Task Force Approach
Identify all possible sources of DRP
Quantify what we can with existing data sources
Consult with outside topical experts
Consult peer-reviewed publications
Identify relative contributions from possible sources
Develop recommendations

19. List of Possible Sources
Point sources
Wastewater treatment plants, Industrial, CSOs, HSTS
Agriculture
Urban/residential
Lawn care fertilizers, storm water, orthophosphate in
treated water, dishwasher detergent
Other
In lake loads/recycling
Streambank erosion
Detroit River/upper lake loads
Transport mechanisms
Subsurface drainage, surface runoff

20. Point Sources
Wastewater Treatment Plants (585 MTA)
Bypasses and Combined Sewer Overflows (90 MTA)
Industry (32 MTA)
Home Sewage Treatment Systems (88 MTA)
Total 796 MTA

21. Point Source Loading to Lake Erie
Direct PS Indirect PS Combined Direct and Indirect
14,000
Total Phosphorus, metric tons
Target Load
12,000
10,000
8,000
6,000
4,000
2,000
0
1967 1972 1977 1982 1987 1992 1997 2002 2007
Water Year

22. Point Source Findings and
Recommendations
Although the load is significant and almost all
bioavailable, it is not the source of increasing DRP
Pursue timely issuance/updates of permits
Evaluate the need to reduce P in effluent based on
TMDL findings, other watershed plans
Pursue implementation of LTCPs
For HSTS: establish statewide rules; ensure proper
design and siting; minimize off-lot discharge; training
for inspection and maintenance

23. Public Water Supplies
Orthophosphate
Many Public Water Supplies began to add
orthophosphate as an anti-corrosive to their
distribution systems in the mid-1990s
Compared PWS phosphate data with WWTP
effluent but saw no discernable increases of
phosphorus
About 15% of finished water is lost from the system
and lawn and garden watering could be an
additional source
Concluded this source is nominal

25. Lawn Care Fertilizers
Products designed for commercial turf management
have low P levels
P in home lawn care products is declining
Starter lawn and “All Purpose” products can have high
P levels, but not a primary market product
Homeowner practices influence potential for runoff
May be more important in urban/suburban developing
areas
Localized problems can occur, but not a widespread problem

26. Urban Storm Water Runoff
Little information on P content in urban storm water
runoff in Ohio tributaries
Impacts could be locally significant
Construction site runoff could be important
Recommend continuation of implementation of Phase
II storm water regulations
Only 8-14% of land in NW Ohio is urban
Could be more of an issue in the central basin

28. Agricultural Nonpoint Sources
Issues examined
Cropping history, acres, rotations, yields
Production practices
Fertilizer use
Livestock production
Biosolids use
Drainage

29. Statewide Historical Ag Trends
From 1978 to 2007
Number of farms from 89,000 to 75,000
Number of farms with cattle have gone from 43,000 to
26,000
Number of farms with hogs from 17,000 to 3700
Number of farms with dairy cattle from 12,689 to 3650
Corn and wheat acreage has not changed.
Soybeans acreage has increased.
Hay acreage has decreased.

30. Phosphorus Inputs
Agriculture
Biosolids
Animal manure
Commercial fertilizer
Recent Fertilizer P Usage
in Lake Erie Basin
(tons elemental P)
11,235 tons
manure, 27%
LEB Commercial P
2,830 tons Fertilizer (2006 Values)
27,320 tons LEB Biosolids Fertilizer
biosolids, 7%
fertilizer, 66% (2007 Avg. Values)
LEB Manure Fertilizer
(2007 & 2008 Values)

31. Historical Fertilizer Usage

32. Balance of Ag Inputs and Outputs
50
40
Excess lb of P2O5 per acre
30
20
10
0
-10
75
77
79
81
83
85
87
89
91
93
95
97
99
01
03
05
07
19
19
19
19
19
19
19
19
19
19
19
19
19
20
20
20
20
Year
Figure 23. Excess phosphate per acre based upon commercial fertilizer sales
information in the state of Ohio, manure generated from animal operations and
the resultant amount phosphorus that theoretically will be land applied, and crop
removal phosphorus estimates based upon NASS information.

33. Trends in Agriculture
Overall, nutrient inputs are down
Biosolids, animal manure, commercial fertilizer
Larger farms, larger fields and larger equipment
Larger equipment has multiple functions, potential
changes in the timing of fertilizer applications
Larger, heavier equipment may be leading to soil
compaction
More year-round operations

34. Trends in Agriculture, cont.
Increase in the use of minimum till and no-till
More fall preparation of seed beds
Changing methods, timing and placement of
fertilizers (i.e. more broadcast application without
incorporation)
Unknown and uncertain use of soil tests and
adherence with recommendations
Changes in soil quality
Changes in drainage

35. Sub-Surface Drainage

36. Channelized Streams and Ditches

37. Findings: Overview
Soil nutrient interactions are key to understanding
nutrient movement
Soil Phosphorus naturally fluctuates between
dissolved and solid forms
Soil mineralogy influences solubility
Soils in the Maumee and Sandusky watersheds are
unique, old lake bed tight clays
Phosphorus export from the Maumee and Sandusky
watersheds are the highest to Lake Erie and also
among the highest in the Midwest

38. Findings
Point sources have remained relatively consistent
Lawn care – can have localized impact, practice BMPs
Mussels have altered P internal cycling
Extent unknown
Processing P from external sources
Transport mechanisms – surface and subsurface
drainage
Relative contribution unknown

39. Findings
DRP tributary loadings are driven by runoff events
Weather trend changes: higher intensity storms, less
snowfall, high winter runoff events
Multiple contributors; agriculture is key
Need to look at how we manage our P inputs
Other factors, including nitrogen, may be affecting
algal blooms

40. Recommendations
Fertilizer
Amount
Timing
Incorporation
Management of field runoff
No single practice will result in lower nutrient runoff

41. Recommendations
Ensure consistent, reliable soil tests
and increase the frequency of testing
Update screening tools that account for agronomic
need and environmental risk (P Index)
Link soil test results to fertilizer recommendations
Link recommendations to applications

42. Recommendations
Push for “Priority Practices” for nutrient management
Use innovative approaches to sell these practices
Pursue the Research Agenda: field to stream to
estuaries/bays to nearshore to in-lake
Review new information, monitor progress, course
correct as necessary

43. Ongoing Efforts
Research projects currently funded by the Ohio Lake
Erie Commission, USEPA-GLNPO, Great Lakes
Protection Fund, Ohio Sea Grant and other projects of
the Millennium Network
NRCS work group evaluating the P Index
Outreach to producers
Lakewide Management Plan (LaMP)
Proposing ecological endpoints (nutrient
concentrations)

45. How many lives
can a lake have?
We don’t want to be
responsible for
writing Lake Erie’s
obituary again

46. www.epa.state.oh.us/dsw
Click: Phosphorus Task Force