Salt+levels+in+water+during+winter+vs.+non+winter+seasons.

Salt levels across the seasons: J.B., Gideon, and Aria.
**Abstract** Over recent times, humans have been having a larger and larger impact on the surrounding world. This can be seen on a large scale, with something such as global warming, or on a smaller scale, with something as simple as road salts being put into local waters. In all cases, the human impact will result in harder lives for animal populations, because our waste will often interfere with their lives and ruin their habitats. For this project, we got to see more detailed how the human impact works on watersheds. We looked at the salt levels in water across seasons, with our hypothesis being that the levels would rise in the winter, which is when roads are salted to prevent slipping. This salt //does// effect the life in the water. Some fish live exclusively in fresh water, others exclusively in salt. When human influence is constantly changing the ratios of salt, it will almost always end badly.

**Hypothesis** It is hypothesized that there will be a clear difference in salt levels ranging from the winter seasons to the non-winter seasons because of outside factors such road salts that dissolve into the water.

**Background** Essentially, what our experiment was testing was whether or not there would be a noticeable difference in salt levels in the water as the seasons transitioned from winter to spring. The two ways we've measured this are by testing both the conductivity and acidity of various water bodies. To make sure we collected a good array of data, we collected numbers from 3 separate sites. Our first site was the main pond area near the picnic benches. Our second site was about 400 yards upstream from the main pond at a little bend in the stream. Our last site was the enclosed pond next to the parking lots. Our first data collection tool was a conductivity meter, which measures the amount of dissolved solids in water. While the conductivity meter can't directly measure salt levels, the trends of the data we got, along with the circumstances of salt being put out during winter, heavily suggests that it is in fact salt in the water that we're measuring. Also worth noting is that we're not only checking for the conventional sodium chloride salt, but we're also checking for other types of salt such as calcium chloride which is also used in road salts. Our second data collection tool was a pH meter, which measures the acidity or basicity of the water. But why is all of this important? Well, salt, like many things, is essential to maintaining life. However, in excess, it can prove deadly to many life forms. In this case, it's obviously fish whose lives could be in danger. In overly salty environments, water will leave the animal's cells to try and reach an equilibrium point with the surrounding environment. If the salt levels fluctuate too much or too frequently, it can cause significant damage to aquatic life. If the aquatic life is affected by salt levels, then the entire trophic structure of the ecosystem will be interrupted because marine life is connected to almost all levels of the food chain.

- GPS (for determining sample location) - Vernier pH meter - Lab Pro data collector - Laptop computer with Logger Pro software - Vernier Conductivity Probe - Camera (optional)
 * Equipment**

The pH meter releases a charge, and what gets returned is reflective of what the pH is. Some ions (The salts in this case) will change the dissociation rate of the water, and therefore either more or less hydrogen ions will be released. The more hydrogen ions, the higher the charge goes, and the lower the pH is. For each single number pH change there is an equivalent of a .25 Volt change. The specific reaction that goes down here, at least for the standard NaCl is: 2NaCl + 2H2O → Cl2 + H2 + 2NaOH.
 * How the pH meter works**

A Conductivity meter basically works by measuring a solution's ability to conduct electricity. The meter first sends a current through the solution that we are measuring, in this case stream water. The current's ability to go through the water is measured in units called Siemens which are Amperes/Volt. So this means that as the current goes through the water, and if there are a lot of ions in the water, then the water's ability to conduct electricity is increased. If there are not that many ions in the water then the water's ability to conduct electricity is decreased. So the road salts that are present in the stream during the winter season would mean an increased conductivity level**.
 * How the conductivity meter works**

Experiment** The experiment as a whole required all our efforts to complete it. Firstly, using a GPS, we recorded the coordinates of the 3 sites we visited. We were then able to focus on collecting the data relevant to our hypothesis. Our first site was the bottom of the main brook next to the picnic benches. For the winter period we hypothesized that at this site there would be higher conductivity and lower pH levels because some of the runoff from the roads would build up around this area. Our second site was about 400 yards upstream at a little bend. For the winter period we hypothesized that this site would have a lower conductivity level because there was less runoff building up there.

**Method** Our data collection method was fairly straight forward. We took our gadgets (GPS, conductivity probe, pH probe, computer) to our 3 sites (see map below) and we would measure the pH, and conductivity of each site. To be sure our results were as accurate as possible, we waited for about 2 minutes during the collection process to let the pH and conductivity levels stabilize. After all, it would be pointless to jot down the results too hastily after all the effort we made to get to Flat Rock Brook. The first time we went there, during the winter season, we took along the GPS so we could record where we went to at each site. When it rained on our last trial run, during the spring season, we also brought along an umbrella so our equipment would not get damaged by the rain.

**Results**

Unfortunately, taking this broad spectrum of locations meant we had to do a significant amount of walking.
 * GPS coordinates**
 * **Site name** || **Latitude / Longitude** ||
 * **Site 1** || N 40 52.716 / W 73 58.169 ||
 * **Site 2** || N 40 52.702 / W 73 58.104 ||
 * **Site 3** || N 40 52.392 / W 73 58.070 ||


 * pH**
 * <  ||< **Feb 10** ||< **Apr 12** ||< **May 18** ||
 * < **Site 1** ||< 8.13 ||< 8.3 ||< 8.37 ||
 * < **Site 2** ||< 8.3 ||< 8.72 ||< 8.81 ||
 * < **Site 3** ||< 6.48 ||< 6.83 ||< 6.9 ||


 * Conductivity**
 * || **Feb 10** || **Apr 12** || **May 18** ||
 * **Site 1** || 70.1 || 64.5 || 63.2 ||
 * **Site 2** || 66.5 || 61.1 || 60.7 ||
 * **Site 3** || 22.9 || 22 || 21.7 ||

**Discussion** Overall, the data reflects a lot of what we were looking for. From the winter to non winter months, there was a steady decrease in the conductivity readings, and a steady increase in the pH levels (even though one went up and the other went down, they both mean that there was most likely less salt in the water). However, what we didn't expect was the individual results from each site we checked. For the most part, we expected the conductivity numbers in the pond (site 1) to be the highest, the mid-stream site (site 2) to be lowest, and the spot next to the bridge (site 3) to be in the middle. Our rationale for this was, since the pond was, for the most part, closed off, we thought that any dissolved solids would enter, but not leave, and the reverse logic goes for why we thought the other spots would have low numbers. We figured, because the mid-stream spot had constantly flowing water, any contaminants and salts would be quickly carried away with the currents. Obviously, our speculation on that front was incorrect. For the pH we thought that the numbers would more or less stay the same with slight variations in pH levels between the individual sites. There are several reasons that the data could have turned out the way it did. Firstly, we can look at the salt trends as they relate to our hypothesis. Clearly, even though it may not have been //as// extreme of a difference as we'd hoped, there was a clear difference between the winter and spring seasons. Our rationale for this was that during the winter seasons, there would be salt placed by the roadside to prevent cars from slipping. Then, when the snow melted or it rained, this salt would be carried into nearby water (our first and third sites were right next to parking areas / main roads). However, the midstream results (site 2) appeared to be nearly identical to the first site, which made us think about ways that could happen, especially because the stream had a heavy flow, whereas the first site had little to no water movement. The first idea we had, is that the salt placed on the road by site 1 didn't have as large effect on the measurements as we thought it might. There are several reasons this may have happened, for example, the ground in that area is extremely level. The salt may have simply not been carried to the water. Or, by the time the water had reached both sites 1 & 2, the salts may have simply dissolved enough so that their concentration was equal anywhere, which also helps to explain why the numbers for the small pond are so much different. The final possibility, is that the salt built up in our second site. At the stream, there were a significant amount of rock barriers which the water went through. If the salt collected on / around the rocks, the conductivity levels s there could have been deceptively high. Another possibility for this is the potential nature of //where// the salt was. Sites 1 & 2 were both part of a larger water movement, one which many times passed by roads which would no doubt be salted during the winter season by the state. However, the quarry pond was on the flatrock property. If the nature sanctuary didn't put down as much salt as the state (Which, considering the effects on life is a definite possibility), then it would make sense that the measurements by the pond would be lower. Yet another possibility is the actual constituents of the road salts. The road salts that many people use include many chemicals different from Sodium Chloride. These chemicals include Magnesium and Calcium Chlorides, which have been noted to slightly acidify water. Therefore when there is less salt like during the spring time, the pH will increase to its normal equilibrium level. These constituents also play a big role in the conductivity levels of the water.

**Potential error** There weren't a lot of ways that error could factor in to this. The largest would be improper cleaning of the tools between measurements. For example, if water from site 1 or 2 was still on the conductivity probe at site 3, it may make the conductivity seem higher than it actually was. There's also the obvious human error potential. For example, there were 3 types of readings someone could get from the conductivity probe. If we were to select the wrong one, it would make our data //very// wrong. However, other than these 2, there isn't really anywhere we could have erred.

**Conclusion** Overall, it seems that our hypothesis was very close to the real numbers. We thought that the salt readings would go down in the spring seasons because of no road salt, and it would seem that is the case. However, we thought that these outside road salts would have a bigger impact on the pH and conductivity levels during winter than they actually did. Our data was for the most part evenly spaced between the individual sites as well as the seasons. From our data we were able to conclude that the pH levels increased while the conductivity levels decreased. Although our project is not about the affect of increased salt levels on the marine life at watershed, it is hard to ignore the potential hazards that the acidifying road salts can have on an ecosystem. To conclude, our data had a clear, concise trend but not to the extreme that we expected.


 * Misc pictures **


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References **1. http://www2.vernier.com/booklets/ph-bta.pdf 2.http://en.wikipedia.org/wiki/nacl 3.http://en.wikipedia.org/wiki/calcium_chloride 4.[|www.vernier.com] 5."Chemistry the Central Science" Brown, LeMay, Burnstein 6.http://www.flatrockbrook.org/features/trails.html