1. Introduction The spark that kindled our curiosity of this topic was just common questions about mercury. What does it do? What are its effects on humans? When does mercury become dangerous to the world and to humans? This lead us to wonder how mercury content changes in populated areas. With research we were able to find some of these answers to our questions. Mercury affects the immune system, alters genetic and enzyme systems, and damages the nervous system, including coordination and the senses of touch, taste, and sight (Mercury In The Environment). Also, toxic effects include damage to the brain, kidney, and lungs. Mercury poisoning can result in several diseases, including acrodynia (pink disease), Hunter-Russell syndrome, and Miniamata disease. Mercury poisoning (also known as hydrargyria or mercurialism) is a disease caused by exposure to mercury or its compounds. Mercury (chemical symbol Hg) is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses (Mercury Poisoning). Most humans are not even aware that they use mercury in everyday life. Exhaust from cars and machines are some of the largest contributors to our atmospheric change. Light bulbs, old paint, batteries and thermostats all have mercury content. It can be harmful if children are around these products too often, because mercury can have harsh neurological, long term effects (What Is the Problem with Mercury). We care about this subject because it could have a serious negative effect on societies around the world. And with a high demand for coal fired energy, and other such products that use or release mercury, our world is heading towards a polluted, unhealthy living space. So do we have to worry about our future in populated areas, and should we pay more attention to Mercury? Hypothesis If we compare the population density to the mercury content in dragonfly nymphs in five states (Maine, Florida, Colorado, Wisconsin & Washington) then Florida dragonfly larvae will contain the most mercury because it has the highest population density. We predict that low population density will mean low mercury content and high population density will mean high mercury content. More people generally leads to more factories that release mercury or a higher number of products containing mercury. Materials and methods To get the data needed to do this project, we used the data that has been gathered from national parks all over the United States. To find this data, people took dragonfly nymphs as a sample and sent them to Dartmouth College for evaluation. This data is the mercury concentration in ppb found in dragonfly nymphs in the state parks. After we found the data we needed, we chose states from different regions of the U.S and found the population density. This information was found after a simple Google search. Afterwards, we compared the population density to the mercury content we found. We made a graph comparing the two so we could see the relationship between the different pieces of information. These are the steps we took to complete our experiment. Acknowledgments We would like to thank all the generous time that our teacher, Ms. Cramer has given us to work on and complete our projects. We also would like to thank the students who collected all of our data and the National Park Service for letting students take samples from various parks across the U.S. All of us, Evan Bloch, Erik Weiss Hartley Walker Money and Lily Doton had an important role in this study, so we would like to give a pat on each other’s back for doing their part and helping create this mercury poster. Results The population density did not relate perfectly to the mercury content in the 5 regions that we researched as a group. Only two of the five closely related to the population density and mercury content, and those two regions were Colorado and Washington. Florida was completely off from each variable. But all in all, the data shows that the population density only went hand in hand when the population was not extremely dense, or not extremely unpopulated. This research did prove that population density generally does not affect mercury content. Conclusions The purpose of this experiment was to compare the concentration of mercury in dragonfly nymphs to the density of the population in states from different regions. The hypothesis stated that Florida dragonflies would contain more mercury than the other state’s dragonflies because Florida had the highest population density. According to the data and the graph, however, we can see that Washington had the highest concentration of mercury with 88.1 ppb average in dragonflies, even though the population density was 102.6 per square mile, the third highest. Some of the states (Maine and Colorado) followed the pattern we guessed, Maine with 43.04 as population density and 15.1 as mercury concentration and Colorado with 49.33 as population density and 34.06 as mercury concentration. An error that could have occurred is that we could have picked a lake within the state that had more or less than the average amount of mercury in the state. There were also different amounts of data for each park, and all the data was collected on different days. This could have an effect on the reliability of the data. There’s always the chance that whoever collected the data could have accidentally contaminated it by touching it or identified the species incorrectly. A way to improve the experiment would be having data from more years and using data from more states in order to have a better comparison. The overall findings indicate that in some cases, the population does seem to affect the mercury concentration in dragonflies, and in others, it seems to have no effect. We have to take into consideration the other factors that could contribute to the amounts of mercury, such as if there are factories in certain states or whether or not the lake we chose was protected. Lily Doton, Hartley Walker Money, Erik Weiss, Evan Bloch Literature Cited "Mercury in the Environment." Mercury in the Environment. N.p., n.d. Web. 04 Dec. 2013. http://www.usgs.gov/themes/factsheet/146-00/ "Mercury in the Environment." Mercury in the Environment. N.p., n.d. Web. 04 Dec. 2013. http://www.usgs.gov/themes/factsheet/146-00/ "Common Products Containing Mercury." Www.deq.state.or.us/. Department of Environmental Quality, n.d. Web. 4 Dec. 2013. http://www.deq.state.or.us/lq/pubs/factsheets/sw/CommonProducts ContainingMercury.pdf "List of U.S. States By Population Density." Wikipedia. Wikipedia,n.d. 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Web. 17 Dec. 2013. http://en.wikipedia.org/wiki/Mercury_(element) "Habitat Destruction." Wikipedia. Wikimedia Foundation, 13 Dec. 2013. Web. 15 Dec. 2013. http://en.wikipedia.org/wiki/Habitat_destruction http://en.wikipedia.org/wiki/Habitat_destruction "Human Overpopulation." Wikipedia. Wikimedia Foundation, 14 Dec. 2013. Web. 14 Dec. 2013. http://en.wikipedia.org/wiki/Human_overpopulation Does Population Density Correlate to Mercury Content?