It is well known that lead from combustible gasoline emissions concentrate and can reside in soils for long periods of time. Lead concentrations were eliminated from gasoline in the mid-1980’s. Prior to this time lead concentrated in soils from gas emissions in high traffic areas in the city of Springfield, Mo. Most of the gas emissions would be carried downwind in respect to the prevailing wind direction, which is W-SW. My hypothesis is the lead concentrations in the soils on Elementary School properties should be higher in those areas where the traffic density was the greatest prior to the mid-1980’s. I also believe the lead concentrations in the soil should be highest in the area on school property, which is downwind and closest to the traffic concentration.
Procedure
I obtained a location map of
the R-12 Elementary Schools and the permission to collect soil samples on
school properties from the R-12 School District Office. I chose 8 Schools for this study. I selected three Elementary Schools, each
located in a high-density traffic area during the time of lead gasoline
usage. These schools are: Rountree,
located near and downwind from the intersection of Grand Street and National
Avenue; Portland, located near and downwind from Sunshine Avenue; Sunshine,
located downwind and on the corner of Sunshine and Jefferson Avenues. I also selected Watkins, which is
located downwind from a street with high traffic density, Kearney, but in a
location farther away from the “Center City Area” of Springfield. I selected four Elementary Schools each of
which was located in lower density traffic area during the time of lead
gasoline usage. These schools are: Disney,
Cowden, Hickory Hills and Pleasant View.
Each
soil sample from each school was collected with a hand hoe and placed in a
small appropriately labeled sandwich bag. Two or three soil samples were
collected from each school property. I
collected samples from three areas when available. These areas were: (1) the closest area on the property facing
downwind from a major road or intersection; (2) on the soccer field; (3) on the
swing, slide or Jungle Gym area. Some of these swing, slide or Jungle Gym areas
were covered with wood chips. When this
occurred, the closest exposed soil sample to the activity area was taken. The above-mentioned collection
areas on each school property are coded.
Next, the samples were taken to the lab to dry.
Each
sample was dried, disaggregated with a mortar and pestle and shaken on a
63-mesh size stainless steel sieve. A portion of each sample passing through
the sieve was weighed to approximately 0.5000 grams and transferred to a
centrifuge bottle to which 10 milliliters of 3N nitric was added. The samples were placed in a hot water bath,
shaken at 80 degrees C for 12 hours and centrifuged. The liquid portion of each sample was placed in a small analysis
bottle. The concentration of lead in
PPM was determined using the Shimadzu Atomic Absorption Analyzer. Microsoft Front Page and Excel were used to
generate table listings and lead concentration trend charts for the purpose of
analyzing the results of the data generated from the chemical analysis.
The
concentration (PPM) of lead in each sample used in this study and the mean
concentration (PPM) of lead in all samples from each school is shown in the first table.
The lead concentration trend chart for all
study samples are shown. The trend
chart showing the mean concentration of lead in the
soil samples for each school is shown.
The
results from the lead concentration tables and trend charts indicate the lead
concentrations in the soils of Rountree, Portland and Sunshine Elementary
Schools are the highest. The next
highest is that found in the soils at Watkins.
The lead concentrations in the soils of the remaining schools are
appreciably lower. For samples
collected at Rountree, Portland, Sunshine, and Disney, the highest lead
concentration at each site was clearly nearest the W-SW corner or closest to
major road area. This was not so
apparent for the samples at Watkins, Cowden, and Hickory Hills and was not true
for the samples at Pleasant View.
The
concentrations of lead in the soils of Elementary Schools in this study is well
below the toxic limits set by the Environmental Protection Agency (EPA) and the
U. S. Department of Housing and Urban Development (HUD). The acceptable concentrations set by these 2
agencies are 500 PPM and 500-1,000PPM respectively. It is interesting to note that the concentrations of lead in the
soils of all samples representing Rountree, Portland and Sunshine Schools are
well above the toxic level of lead in soils for school playground areas in
Sweden established by the Swedish government.
Conclusions
The concentrations of lead in the soils of the Elementary School properties in Springfield Missouri was found to be highest in the area of highest traffic density present during the time when lead was an ingredient in gasoline. The lead concentrations were low in the soils of Elementary Schools in the areas of low traffic-density present during that same time. Lead concentrations in the soils decrease from the source within the same Elementary School property. All of the above results agree with my original hypothesis concerning this project. The concentrations of lead in the soils of Rountree, Portland and Sunshine Elementary Schools could be considered toxic by some national agencies.
Acknowledgements
I wish to thank Mr. William Dawson of the Springfield R-12 District Office for a copy of the R-12 Elementary School Location Map and for the permission to collect soil samples on the school properties. I wish to thank the Chemistry and Geography, Geology and Planning Departments for the use of their equipment and facilities. I wish to thank my father, Dr. Erwin J. Mantei who acted as a mentor for my project. He helped and supervised me while using chemical reagents and the Atomic Absorption Analyzer. He also helped edit this project report. I also wish to give special thanks to my teachers at St. Agnes Elementary for their help and encouragement.