Page 147 - Environment: The Science Behind the Stories

net input of 4.52 kg (10 lb) of phosphorus per year, promot- These approaches have widely varying costs for the
ing phosphorus accumulation in soils, runoff into waterways, same level of nutrient reduction. For example, embrac-
and phytoplankton blooms and hypoxia in the bay. People ing approaches such as planting vegetation buffers around
also add phosphorus to waterways through releases of treated streams, restoring wetlands, and practicing sustainable agri-
wastewater rich in phosphates from domestic use of phos- culture can reduce nutrient inputs into waterways at a fraction
phate detergents. of the cost of other approaches, all while creating habitat for
wildlife (Figure 5.21). Ultimately, the approaches embraced
Tackling nutrient enrichment requires depend on the major sources of nutrients for a given waterway
along with economic considerations.
diverse approaches

With our reliance on synthetic fertilizers for food production
and fossil fuels for energy, nutrient enrichment of ecosystems WEIGhING ThE ISSUES
will be a challenge for many years to come. But there are a NUTrIENT POLLUTION aND ITS FINaNCIaL IMPaCTS A siz-
number of approaches available to control nutrient pollution able amount of the nitrogen and phosphorus that enters the
in the Chesapeake Bay watershed, Mississippi River water- Chesapeake Bay originates from farms and other sources far
shed, and other waterways affected by eutrophication: from the bay, yet it is people living near the bay, such as oyster-
men and crabbers, who bear many of the negative impacts.
• Reducing fertilizer use on farms and lawns
Who do you believe should be responsible for addressing this
• Changing the timing of fertilizer application to minimize problem? Should environmental policies on this issue be devel-
rainy-season runoff oped and enforced by state governments, the federal govern-
• More effectively managing manure applications to farm- ment, both, or neither? Explain the reasons for your answer.
land to reduce nutrient runoff
• Planting and maintaining vegetation “buffers” around
streams that trap nutrient and sediment runoff A systemic approach to restoration
• Using artificial wetlands to filter stormwater and farm offers hope for the Bay
runoff
• Restoring nutrient-absorbing wetlands along waterways The Chesapeake Bay finally has prospects for recovery as the
• Improving technologies in sewage treatment plants to federal government and bay states are now managing the bay
enhance nitrogen and phosphorus capture as a holistic system. Arriving at this endpoint was not easy,
though. After 25 years of failed pollution control agreements
• Restoring frequently flooded lands to reduce runoff
and nearly $6 billion spent on cleanup efforts, the Chesapeake
• Upgrading stormwater systems to capture runoff from Bay Foundation (CBF), a nonprofit organization dedicated to
roads and parking lots conserving the bay, sued the Environmental Protection Agency
• Reducing fossil fuel combustion to minimize atmospheric in January 2009 for failing to use its available powers under the
inputs of nitrogen to waterways Clean Water Act to clean up the bay. The CBF’s lawsuit focused

$500+ $92.40 Stormwater
Cost of reducing nitrogen pollution ($ per lb) $47.40 WWTP

Agriculture
New practices

$21.90
$15.80
$7.00 $6.60 $4.70 $3.30 $3.20 $3.20
$3.10 $1.50 $1.20
Stormwater WWTP WWTP Algal turf Land Grassed Restored/
retrofits upgrades upgrades scrubbing retirement buffers constructed
(High) (Low) wetlands
Stormwater Enhanced Native oyster Cover Conservation Forest Forest harvest
management for NMP aquaculture crops tillage buffers best management
new development practices
Strategy
Figure 5.21 The cost per pound of reducing nitrogen inputs into the Chesapeake Bay varies widely.
Approaches slowing runoff to waterways avoid nitrogen inputs for a few dollars per pound, whereas upgrades
to wastewater treatment plants (WWTP), enhanced nutrient management plans (NMP—careful regulation of
nutrient applications), and stormwater upgrades can be considerably more expensive.
For what it costs to remove 1 pound of nitrogen by using enhanced nutrient management programs
(NMP), how many pounds of nitrogen could be kept out of waterways by planting forested buffers
146 around streams instead?

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