Field Research Project: Soil and Air Contaminants
On October 10 and 11, 1998, our research team traveled to four locations in Milwaukee, Wisconsin to conduct our study. Our purpose was to test the soil and air for contaminants and to find a correlation between the four locations we chose and the mean wind direction. Using the La Motte air and soil test kits we tested for the contaminants. The three contaminants tested for in the air were carbon monoxide, nitrogen dioxide, and sulfides. Soil contaminants that we tested for were sulfides and nitrates. We also measured the pH of the soil. We found there to be little to no detectable contaminants in the air. The soil test produced similar results. Based on standard deviation calculations and T-test analysis, our results were inconclusive.
Key Words: contaminants, wind direction, air pollution, soil pollution
The presence of nitrates and sulfates in the soil is critical to plant growth (Gibson and Batten, 1970). Nitrogen is a component of proteins, nucleic acids, coenzymes, and chlorophyll. Phosphates are important in the composition of phospholipids, ATP, and nucleic acids (Starr and Taggart, 1993). The pH of a soil also directly effects plants growth, the majority of plants favor a neutral soil as opposed to one that is acidic or basic. Therefore, determining the levels of nitrates, phosphates and pH on can determine whether or not the soil is suitable for plant growth. Plant growth in an area can be used as an indicator of pollution as can the levels of nutrients being tested. Contamination of air was evaluated by examining the carbon monoxide, nitrogen dioxide, and sulfide levels. There have been many studies related to the research we performed. We have found that "a starting array of the most dangerous by-products of industry and agriculture are being transported across the U.S. by wind" (Brown, 1987). This led us to speculate about the contaminants being spread through the wind from Milwaukee’s industrial areas. We also reflected on the movement of chemicals from the air into soil (Thibodeaux, 1979). This further contributed to the hypothesis we developed. We speculated that the amount of contaminants would be greater in the direction of the wind, base on the premise that the wind would spread the contaminants. Subsequently, our hypothesis states that contaminants would increase in the soil and air in the mean direction of the wind from a source of pollution.
On October 10, 1998 at 11am the temperature was 64° F. It was partly cloudy. We chose our central site, near a large factory, underneath the North end of the 27th Street viaduct. The wind direction was 60° at all sites. We conducted soil tests and air tests according to the directions of the La Motte Company Kits.
On October 11, 1998 around 9am the temperature was also 64° F. It was foggy and overcast this morning. Again we conducted our soil and air tests with the La Motte tests. We tested the air for carbon monoxide, nitrogen dioxide and sulfides. We tested the soil for sulfides, nitrates and pH. Our sites were as follows: Site 2 = Northwest corner of 35th and McKinley Blvd. This site was at 0° (refer to diagram #1 for explanation). Site 3 = Southwest corner of 35th and Greenfield Ave. This site was at 180° . Site 4 = Southeast corner of St. Paul Ave. and Greves St. This site was at 90° . Site 5 = Southeast corner of Walker Dr. and Juneau Ave. in the V.A. Cemetery. This site was at 270° . All of our sites were approximately 1 mile from our central site, which had a wind direction of 60° .
Few variations were found among sites. This was supported by the T-test data. The only contaminants we found in the air were at Site 1, in which we found 75 ppm carbon monoxide. There were no differences in the amounts of sulfates in the soil among any of the sites. The pH varied minimally from site to site. The sole difference found in nitrate concentration in the soil was in site 1. Site 1 had 10 ppa of nitrates, where the other sites all had 20 ppa. A qualitative analysis of the sites and wind direction yielded the following results seen in the Degree diagram.
Data is included in our data sheets.
Based on the data, there were very few differences in the amounts of contaminants among our chosen sites. We hypothesized that we would find more contaminants in the mean wind direction. Aside from pH there wasn’t a detectable increase in contaminants comparing site 1 to the other sites. In conclusion the T-test data along with the qualitative analysis diagram support the inconclusive nature of the experimental results. Therefore we did not support our hypothesis. However, there is evidence to support the hypothesis we posed.
The EPA data reports from 1987-1991 reported that the Milwaukee area had an annual average of 10.4 days with excessive ozone in the air (Newmann, 1998). Nitrogen oxides, which we tested for, are the chief components of ozone. Subsequently, the EPA launched a Clean Air Act enforcement initiative, targeting factories in southwestern Wisconsin (Newmann, 1998). As a result, the ozone levels from 1992-1997 dropped to 2 days per year over the federal limit (Newmann, 1998).
There are many variables that must be take into account as having an affect on the results. The weather could have been a determining factor, as well as the fact that the tests were conducted on a weekend. This could have skewed the results due to the fact that the pollutant sources may have been inoperable for several days. There is also the possibility that the test kits were not as accurate as we had hoped or the amount of variance may not have been detectable by our kits. If we conducted our tests today the results we get may be different. Also, we may not have chosen a far enough distance away from the polluted sources to detect any differences.
A study conducted by the National Park Service revealed that a coal fired power plant located 12 miles form the northern rim of the Grand Canyon, may have contributed to the air pollution at that site (Current Science, 1989). Subsequently, we may be able to conclude now that a 1-mile radius from the polluted source was not sufficient. All of these variables note the possibility of error; however, it could also be the fact that the levels of pollution were just that low.