Environmental Life Cycle Assessment of Southern Yellow Pine ...

EXECUTIVE SUMMARY
Indicator results in Table 1 show that a significant volume of untreated hazardous waste is generated
in the BAU scenario – over 590,000 tons over the 40-­‐year time horizon. The difference between the
BAU and SPR scenarios is enough hazardous waste to completely fill nearly 300 Olympic-­‐size
swimming pools.
1.6 Discussion of the Environmental Advantages of the BAU Scenario
1.6.1 Lower Land Use Ecological Impacts in the Mesabi and Marquette Iron Ranges
As shown in Table 1, the BAU and SPR scenarios impact different regions with different biomes and
species affected. The BAU scenario does not impact three terrestrial species and one biome in the
Mesabi and Marquette Iron Ranges. These lowered impacts include disturbance to Western Great
Lakes forests, and the habitat of the Kirtland’s warbler, Wood turtle, and Blanding’s turtle..
1.6.2 Lower Emissions Affecting Regional Acidification
The BAU scenario category indicator results are lower for Regional Acidification. The emissions in the
SPR scenario classified in this impact category are dominated by those resulting from steel
production, hot-­‐dipped galvanization, and zinc smelting; most of these emissions are occurring in the
Midwestern United States and Great Lakes region. These regions have sensitive soils, and a large
fraction of acidifying emissions from steel production in this region deposit in sensitive areas, and can
lead to acidification. In the BAU scenario, most emissions result from the electricity generation used
in the production of the CCA treatment chemical. Though also occurring in relatively sensitive
regions, the level of acidifying emissions in the BAU scenario is less, leading to a smaller indicator
result.
1.6.3. Lower Emissions Leading to Ground Level Ozone and PM 2.5 Exposure Risks
The BAU scenario results in fewer risks of the exposure to humans from both ground level ozone and
fine particulate matter (PM2.5). In the SPR scenario, the production of steel is the largest contributor
to results for both of the impact categories of Ground Level Ozone Exposure Risks and PM 2.5
Exposure Risks. In the SPR scenario, the unit processes associated with steel production are
concentrated in the United States Midwest and Great Lakes regions, both of which have relatively
high population densities. This results in larger exposure risks from the emissions classified in these
impact categories. In the BAU scenario, most emissions result from the production of the precursors
going into CCA production, and the installation of wood utility poles. Though also occurring in
relatively densely populated regions, the level of emissions in the BAU scenario is less, leading to a
smaller indicator result.
1.6.4. Zinc Resource Depletion
The depletion of zinc resources is a clear advantage of the BAU scenario. For galvanized steel utility
poles, zinc provides a sacrificial coating and very little zinc is recovered at end-­‐of-­‐life.
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