Sweet Home Project Proposal

I. Introduction

            The goal of this study is to determine the relationship between arsenic concentration in streambed soil and population density and shell color of the freshwater snails of genus Lymnaea. Our goals are to determine useful testing sites based on previous arsenic testing, make use of any previous studies in similar areas, and collect new data and soil samples to be processed using neutron activation analysis at OSU. The results of this study will be entered into a GIS database that will facilitate further studies to improve the characterization of arsenic over time.

            We have decided to perform this study because it has been well established that there is an abnormally high concentration of arsenic in the Sweet Home area, and it is important that we find whether this has a negative effect on the human population of the area. By studying the wildlife that inhabits areas that are known to have especially high arsenic concentrations and comparing the characteristics of these animals with similar animals in areas that have normal arsenic concentrations, we can determine whether arsenic is having an impact on wildlife. Studying aquatic rather than terrestrial animals could prove more effective because animals that need to be constantly submerged in water will not be able to leave the arsenic-rich environment, as would a squirrel or an airborne insect. Therefore, we can be more certain that the animals we are studying have been exposed to high-arsenic conditions. If our data shows that the arsenic concentration in the Sweet Home area has a negative impact on wildlife, it would be important to perform a more thorough investigation on the specific effects the arsenic has had on the human population, and what should be done to reduce the arsenic concentration.

            In 1996, the U.S. Geological Survey determined that there was an anomalous area of high arsenic concentration around the town of Sweet Home. Starting in 2002, Crescent Valley students began an investigation of the arsenic issue (Kirsch, 2003). As a part of this study, we are studying the effects the arsenic has on animal populations in the area. In a previous study, populations of Lymnaea Emarginata (pond snails) began to die when exposed to arsenic pentoxide and arsenic trioxide in concentrations of 900 to 1000 m g/L (Orme, 2002). This information would lead me to believe that the arsenic in Sweet Home does have an impact on the area’s wildlife. However, we don’t yet know whether the concentration of arsenic in water is as high as in soil. It could be that most of the arsenic is in the soil and has not been dissolved into the stream water in large amounts. In Bangladesh, where arsenic in soil is also an issue, researchers found little correlation between concentration of arsenic in soil and concentration in water used for irrigation (Meisner, 2002 and Harvey et al., 2002). This could or could not be a factor in our investigation. There has not been any study of snail shell color in relation to arsenic concentration, but it has been studied in relation to other factors, including food supply and environment. The species studied was Littorina Obtusata, a saltwater snail. In the study cited, its color ranged from light yellow to dark brown and olive green (Machala, 2002).

            The results of this study will be valuable to other scientists as well as the citizens of Sweet Home and the surrounding area. Scientists will be interested in this study because our results could be useful to future studies in similar fields. If this study determines that arsenic contamination is a serious problem in Sweet Home, other scientists will be interested to use our data for further investigation. Our results could be particularly useful to future science classes at Crescent Valley who will be continuing the Sweet Home project and may be interested in a similar topic. In Sweet Home, the local government will be interested to see the results of the project as a whole, including our study. If arsenic contamination presents a significant problem to Sweet Home residents, the city planners might want to consider finding an alternative source of water for the city or develop a water treatment facility that removes arsenic before it reaches peoples’ homes. If we determine that arsenic contamination is not a problem, the city of Sweet Home may want to commission further studies to confirm our results or investigate other types of wildlife that might respond to arsenic as humans would.

            In this study, we expect to see a correlation between the arsenic concentration of streambed soil and the population density and color of snails. In previous studies, arsenic compounds have been shown to affect snail populations, and snail shell color has been shown to change under different living conditions.

II. Methods

            In order to achieve a more balanced and accurate set of data, we have chosen three different areas to collect samples. At Ames Creek in Sweet Home, we expect to find high arsenic levels in streambed soil. We will also collect samples at Quartzville Creek and in the Santiam River below Foster Dam, where we expect to find less arsenic in the soil. At each of these sampling areas, we will choose 3 sites in the body of water that are approximately 15 meters apart and mark off 1m x 1m areas at each site. We will be working in shallow water to make our collection easier. Each site will be marked off by placing stakes under the water and making a square area. In each of the three areas, we will measure the population density of snails by picking up rocks from the streambed and placing all the snails we find into a bucket specific to that 1 m² site. By counting the number of snails in each bucket, we will have three different values for population density for each area, from which we will be able to determine an average population density for the area. Before we release the snails back into the water, we will photograph them with a digital camera to document the physical characteristics, especially color, of the snails. Later, we will use these photos to produce descriptions of the color of the snails. Under ordinary circumstances, aquatic snails are dark gray or black. We expect to see some change in high-arsenic conditions. After we have counted the snails, we will take samples of streambed mud at three of the four corners of each 1 m² area and put them in a separate bag for each site. This means we will have a total of nine bags when we are finished. These samples will be dried according to the INAA drying procedure and prepared according to the INAA sample preparation procedure. We will use neutron activation analysis to find the amount of arsenic in each of these samples.

Materials:

Rubber boots - Leif

3 buckets – Sean

Shovel - Megan

Ziplock bags - Justin

Digital camera - Megan

Gardening stakes - Leif

String or cord - Sean

Maps - Sean

GPS - Megan

III. Timeline

IV. List of Data to be Collected

• 3 different snail population densities each for Ames Creek, Quartzville Creek, and Santiam River (total of 9)
• Qualitative data for snail color characteristics for each area of test
• 3 different arsenic concentrations from soil samples for each area (total of 9 samples)

V. References

1. Charles F. Harvey, Christopher H. Swartz, A. B. M. Badruzzaman, Nicole Keon-Blute, Winston Yu, M. Ashraf Ali, Jenny Jay, Roger Beckie, Volker Niedan, Daniel Brabander, Peter M. Oates, Khandaker N. Ashfaque, Shafiqul Islam, Harold F. Hemond, and M. Feroze Ahmed. "Arsenic Mobility and Groundwater Extraction in Bangladesh." Science 2002 November 22; 298: 1602-1606.
2. Meisner, Craig A. "The Arsenic Hazard in Bangladesh Agriculture." http://www.cimmyt.org/bangladesh/Arsenic/arsenic_in_bangladesh.htm. 2002.
3. Orme, S. and Kegley, S. "PAN Pesticides Database – Chemical Toxicity Studies on Aquatic Organisms."

http://www.pesticide info.org/PCW/List_AcquireAll.jsp?Species=2172.

4. Machala, Ellen. "Litorina Obtusata and Color Morphology." http://www.clarku.edu/departments/biology/biol201/emachala/. 2002.

5. Kirsch, Adam. Sweet Home Arsenic Project. 2003.