According to the data collected, my hypothesis was supported. I hypothesized that with a higher concentration of NaCl in the water, the Z. palustris seeds will be less likely to germinate, and therefore have a lower success rate for germination. As Figure 3 shows, the highest level of NaCl concentration (1000mg/L NaCl) had the lowest germination success rate. The highest success of germination occurred in the solution that contained no NaCl, the control. This data suggests that Zizania palustris is not salt tolerant and therefore undergoes difficulty in any concentration of salt.
As mentioned earlier, a major contributor to heightened lake and river salinity levels is road salt de-icer. Most traditional de-icers use NaCl as their main chemical. Through storm water run off, this salt ends up in groundwater and surface waters alike. Around the same time that this type of de-icer was introduced and commonly used, Zizania palustris disappeared from the Wingra shores with no trace. With the data in Figure 3, this suspicion is given some evidence.
The most interesting aspect of this experiment can be seen when Figure 3 and 4 are viewed together. From Figure 3 one can deter that any concentration of NaCl dramatically affects the germination success rate of Zizania palustris. Even at 100mg/L NaCl, there is less than 25% success in germination. Figure 4 shows the average salinity levels in areas in the Lake Wingra Watershed. The lowest concentration present occurs in Lake Wingra at an average of 120mg/L NaCl concentration. Therefore, even in the area with the lowest concentration of NaCl, Zizania palustris would not be successful. If we ever want to be able to grow a native wild rice such as Z. palustris in this area again, we should immediately cease road salt usage and begin a long process of phytoremediation in order to rid the Lake and surrounding areas of concentrated salt content.
This study is exceedingly important to the future health of vegetation in the Lake Wingra watershed. By studying the direct effects of NaCl and road salt use on local vegetation, awareness on the effects of certain ‘convenience chemicals’ is risen. Further studies similar to this would be useful in determining other side effects of road salt usage. Some problems encountered in this study could have been avoided. Aeration of each beaker may have been important. After two days, the water in each test beaker became cloudy. In the real world, the seeds would be germinating in some sort of moving water. By using an air tube that blows air into each beaker, this problem might have been avoided.
The levels of NaCl concentration were not ideal for this study. Highest recorded chloride concentration in the Dane County area was almost 5,000 mg/L. Perhaps a higher range of concentrations would yield more accurate and conclusive results. For future studies I would suggest using 0, 100, 500, 1000, 3000, and 5000mg/L NaCl.
On Edgewood’s campus many students and faculty are taking notice to the effects of common road salt. For this reason, the college has invested their time and effort in finding new ways to keep roads and sidewalks safe without endangering the health of nearby lakes and springs. Currently, a different form of de-icer is being used. Some alternative de-icers contain potassium formate which also helps to break down ice and snow. Unlike straight NaCl, recent studies have shown that potassium formate is less damaging to groundwater. The Finish Environmental Institute (SYKE) conducted a study from 2002-2003 concerning alternative de-icers. By ceasing the use of traditional NaCl road salt and replacing it with potassium formate based de-icer, researchers found sodium and chloride concentrations in groundwater nearby the road decreased, with the maximum reduction of more than 40 %. Because of this dramatic data, they are reviewing the new chemical currently in order to determine any further possible effects. Unfortunately, this more environmentally friendly de-icer comes at a high price, nearly 15 times the cost of regular road salt. Because SYKE is more concerned with groundwater quality and not the effects of salt on native plant species, I would be interested to see if the newer/’safer’ de-icers have any negative or positive effects on plant growth. By conducting this same experiment but exchanging NaCl with a form of potassium format, I would be able to review the safeness of the new product (Nystén et al., 2003).
Fortunately, this increase in salinity of natural streams, lakes, and river is not going unnoticed. Researchers at the University of Maryland Center for Environmental Science have been studying the changing salinity levels in nearby bodies of water for the past thirty years. From the data collected, they are trying to determine the future of our groundwater if these increasing trends continue. Current projections claim that many surface waters in the region could become unfit for human consumption and toxic to some aquatic life. Reversing this problem, however, appears to be more difficult than expected. “Concentrations are high in the summer, not just in the winter when salt is applied to melt snow, suggesting that salt is accumulating in the environment," said Dr. Peter Groffman, of the Institute of Ecosystem Studies (UMCES, 2005).
Similar studies involving the effects of salinity in plants have been conducted. Following a number of these studies, the effect of salinity depends entirely on the type of plant subject used. In one study by Papadantonakis et al. (2006), NaCl and CaCl2 concentrations were used to determine the effects of chemicals on the cucumber plant and its fruit production. Researchers found that NaCl concentrations had a greater negative effect on fruit production and overall health of the cucumber plant. CaCl2 had some effects on the plant; however, they were not as notable as the effects of NaCl.
Certain technologies have been developed to simplify and improve life for human beings. However, it is exceedingly important that we remember that each of these technologies has an effect on the world around us. It is up to us to make important decisions regarding our contribution to the health of the world. In situations such as this, all possibilities must be explored in order to develop an appropriate solution.