Winners of the Ecological Footprint Blog Competition

The UST Sustaining Students blog aims to provide students with an outlet to share opinions and research findings on a variety of topics related to sustainability. This blog is a sister blog to the sUSTain blog, a faculty run blog with a similar goal. Any students with a passion for sustainability are invited to submit pieces to the editors and work in revisions in order to get their ideas published.

Below, we present posts from a sophomore level class in the Biology Department, BIOL 209 – the Biology of Sustainability. The posts came from a lab in which students were asked to calculate the amount of three important elements: carbon, nitrogen, and phosphorus that flow into and out of their households, and to compare those fluxes to those of other Twin Cities residents. The flux calculator was an offshoot of the Twin Cities Household Ecosystem Project, described in a recent paper by University of Minnesota researcher Cinzia Fissore and colleagues. Students were then asked to write a blog post about their findings. We received about 140 entries for the competition. Below we present the grand champion post by Margaret (Meg) Thompson, and three runner-up posts (by Jacob Jerrard, Michael Chmielewski, and Fallon Macemon). Honorable mentions were by Marissa Peine, Hannah Dahl, Jacob Geraghty, and Casey Nightingale. Congratulations to the winners, and thanks to everyone for participating.

Grand Champion!

“Living the Dream”

 by Margaret Thompson

When most people describe their ultimate goal in life, they use words like “success”, “money”, “happiness”, and maybe even “huge”, “luxurious”, or “extravagant.” But how many people would say the American dream is living in a modest-sized, economically viable and environmentally sustainable house causing no more environmental impact than they need to survive?

I certainly wouldn’t. Although I consider myself more eco-friendly than your average Cheetoh-chomping American teenager, with my organic granola and recycled paper notebooks, I realized there’s a lot more I could be doing. I took the Household Flux Calculator (HFC) test to quantify my impact on the carbon, phosphorus and nitrogen cycles. Not surprisingly, my outputs are significantly lower than the average person’s. As a college student, my lifestyle is a lot simpler than that of most adults, but what if I had the resources and time and energy to live as my comfort zone dictates? In some sense, the fact that I’m a poor college kid forces me to have a less than average flux. I can’t afford a larger apartment, more processed foods, or a car.

But if I could afford them, I would have them, and maybe that’s the problem. In lecture we’ve come across several papers stressing the importance of a drastic shift in society’s attitude towards sustainability, rather than just development of new technologies or enforcing certain policies. One paper insists upon a radical redesign of the food system to control the extreme phosphorus pollution we are facing in our waterways, and after seeing my results of the HFC, I saw how much phosphorus waste my own food habits generate. I began to think about what little things I could do to reduce my impact in that area.

According to a report studying the lifestyles of Twin Cities residents, certain households have a disproportionate effect on the environment, contributing much more C, N, and P than the majority of households and much more than they need to survive. This disproportionality indicates the attitudes that have driven overconsumption and excessive lifestyles for many years, and despite some really great initiatives, there’s so much more work to be done. You could say we need to have an attitude of constant vigilance. But I prefer to take on a position of constant optimism. If we really want to live sustainably, we have to start believing that what we do every day really can make a difference. Even as a poor college kid, my choices can do some good for the earth. For my part, I’m definitely going to be more conscientious about the food I buy, and composting, recycling, and reusing what I can, wasting only what I need to. But I’m also going to think about my lifestyle choices in a broader sense, and try to consider success in a new way. There needs to be a new American dream, and this time its colors are red, white, blue, and green.

1st runner up

“Island life”

by Jacob Jerrard


Island life.

Items you use must be brought across the water from far off lands, and the waste you are left with must be managed responsibly. You choose what comes in and you choose what comes out, but if you do not find a way to manage these “fluxuations” of resources, you’ll not only ruin your island, but your neighboring islands as well!

Our individual households are like islands, and unfortunately, the resources available to us are limited. Resources must be imported. We bring phosphorous and nitrogen to our islands mainly in the form of food and fertilizer, and output it through waste, wastewater and to the landfill. Transportation and machines utilize nitrogen and carbon and these resources leave our islands through nitrogen oxide and CO2 gas. Our islands are in a constant state of flux as these resources flow in and out. Close attention must be paid to your island’s outputs, because if left unchecked, the surrounding island community may suffer.

And this is exactly what is happening in our very own residential communities today.

The Twin Cities Household Ecosystem Project quantified the average amounts of nitrogen, phosphorous, and carbon imported and exported by households in Anoka and Ramsey counties, in Minnesota. After crunching some data, it was revealed that a relatively large amount of households showed below average consumption and export, while only a small amount of households contributed largely to the overall export levels. In other words, a few irresponsible islands are tainting the surrounding waters.

The project developed a calculator where people can determine individual household resource fluxes. I spent a mere fifteen minutes entering my family’s household variables and was instantly gratified with insight into my family’s resource usage.

My family’s carbon emission was about 2157 kg a year, which was only a third of the carbon an average household outputs. Considering a main source of carbon output arises from transportation, and that my family rarely drives and does not use air travel, I don’t find this low value surprising. My family tries to only use the air conditioner when absolutely necessary in the summer, and in the winter, the thermostat stays put at a lovely 68 degrees Celsius, which really cuts down our fossil fuel energy consumption (and saves some money on the electric bill to boot!).

For nitrogen and phosphorous, my family used a little more than the average household in both categories. There’s a crazy amount of nitrogen and prosperous the food we eat (75% of a household’s nitrogen output and 60% of a household’s phosphorous output comes from human and pet food!). Meats are full of these elements and unfortunately my family is full of meat eaters. To make matters worse, our numbers were probably higher considering we have two fluffy cats that always seem to be hungry. My family could easily bring our numbers down if we could simply switch to a less meat intensive diet.

All in all, manage your island’s resources responsibly… or else you’ll find yourself stranded in some stormy waters.

2nd runner up – tie

“Green: Just a Color”

by Michael Chmielewski


I like to think that I live in my own little “green,” eco-friendly world. I would even somewhat confidently label my lifestyle choices as “sustainable.” I try to recycle, don’t leave the water running when I’m shaving in the morning, and usually choose to bike when given the option or driving a relatively short distance. Usually.

How often do we as American citizens use the words “green” and “sustainable” interchangeably? Many would argue that the two words are equivalent. Yet according to a recent paper by Joseph R. Burger and colleagues, the two terms “green” and “sustainable” do not carry the same meaning.

Take Portland, Oregon. This metropolitan area is considered to be the “greenest” city in the United States. Portland has outstanding bike paths, obtains 8% of its power from hydroelectric sources, and offers citizens a healthy lifestyle. But consider this: if Portland were to be barricaded from all outside sources, how sustainable would it be? Annually, Portland consumes 1.25 billion liters of gasoline, 28.8 billion megajoules of natural gas, and 31.1 megajoules of electricity. In comparison with other large metropolitan areas in the United States, it ranks about average in carbon footprint. In other words, Portland may be considered “green,” but by what standard? Definitely not in terms of sustainability.

But before we go pointing fingers at Portland, what about ourselves? I recently took a Resource Flow Calculator survey to determine my household’s carbon, nitrogen, and phosphorus flux levels. Honestly, I do have to say that I was a little surprised at the results, especially in regard to nitrogen and phosphorus flux levels. Our carbon footprint was understandably low (below average), given the relatively low amount of air travel and the decent amount of automobile travel. Something surprising was that the automobile travel between three cars contributed significantly greater than any other factor to the carbon footprint: 2954 kg C of 4727 kg C total (over 62%).

Another surprising element of the survey was the incredible amount of nitrogen represented in my diet (which consists of meat, fruits, and vegetables). I had always laughed at those who douse their meticulously manicured, artificially green lawns with nitrogen fertilizer on a seemingly daily basis. Apparently diet is also a major contributor to nitrogen fluxes.

Finally, my phosphorus levels were way off the charts (much higher than average). The main contributors to this value were my diet (again) and wastewater. I guess that I should try shaving without water from now on…

But is that what it’s really all about, just cutting back? It is certainly part of the cure. Yet I believe that there is more than meets the eye behind transitioning from a “green” mindset to one that can be determined “sustainable.” Approaching sustainability will take a change in standards, a change in thought. It may not be possible to make a noticeable difference by living more modestly, but one can certainly lead by example. After all, we’re all in this together.

2nd runner up – tie

By Fallon Macemon

What is your flow? In other words, what are your household’s carbon, phosphorus, and nitrogen footprints?  After taking the Household Flux Calculator Survey designed around Twin Cities residents [], something I encourage you all to do, you may feel a tinge of guilt if your results proved to be anything like mine did.  That being said, humor me, while I share with you the story of a natural resource-aholic. Oh yeah, that’s me!  My household total carbon footprint was 16,044 kg, a staggering 7,906 kg above average!  To put that in perspective, my household uses four adult killer whales worth of carbon each year.  Not only was my carbon footprint above average, so too was my household’s nitrogen footprint totaling 71.7 kg, 23.4 kg above the average household for the Twin Cities.  Since I’m not one to tell a lie, it seems fair to share with you yet another disappointing statistic, my household’s phosphorus footprint value of 7.12 kg, 3.04 kg, again, above average.  Why might you ask am I sharing my natural resource addiction story?  Because, just like many of you, I was unaware of how devastating the effects of prolonged over usage of precious natural resources have on our Mother Earth.

A study conducted by Fissore et al. in the Twin Cities area, which used the same survey I did only for the whole metro area, found that the two greatest factors influencing the carbon footprint was home energy usage and vehicle/air travel.  That sounds about right, considering the fact that my household’s greatest carbon input was vehicle travel, totaling 12,369 kg.  So how can my household and your household make substantial cuts in our carbon footprints while still being realistic?  For starters, riding our bikes more regularly (location permitting) instead of driving our cars would help immensely.  Also, to combat the high household energy usage, we can unplug appliances when they are not being used, rely more on natural light, and watch less television, a little fresh air never hurt anyone!

When it came to nitrogen footprints, the Fissore et al. study found that diets, particularly diets high in meat, coupled with lawn fertilizer were the dominant factors that increase nitrogen output.  These findings varied from my results, given that 43.2 kg of my 71.7 kg of nitrogen were attributed to vehicle travel (no surprise there!) and only 4.0 kg were due to lawn care.  So what’s my advice to you for making a realistic cut in household nitrogen levels?  Eat. Less. Meat.  In other words, Eat. More. Fruits. And. Vegetables.  Many of us can agree that meat is not only good for our health, but just as good or better for our taste buds.  However, there are a number of ways to attain the same nutrients in meat through other means of food products.  Oh yeah, and maybe let nature run its course on your lawns, forget the fertilizer, or at least try and reduce the number of times you use it.

Last but not least, Fissore et al. stated that phosphorus footprints were 98% attributed to human diet, detergents, and pet food usage.  I hate to say this, but again, this sounds about right as 4.20 kg of my total 7.12 kg of phosphorus was due to detergents.  By now my hope is that you like my advice, but chances are it is scaring you.  But by switching to detergents that are phosphorus-free and feeding our pets food that has minimal phosphorus levels is a start to aid in the fight against increasing phosphorus footprints.

It’s no surprise that my natural resource footprint was above average in all areas of study.  I come from a family of 8 people, we have 5 dogs, and my siblings spend a lot of time in the car for their jobs.  However, that is no excuse.  Being that my family is so large, it is even more crucial for us to adopt new and environmentally friendly ways of living, and yes that may mean giving up some of the “good life”.  We live in America, a developed society set in our ways, but the facts are there: carbon, nitrogen, and phosphorus levels show no signs of slowing down and that only means devastation is on the horizon.  And yes, I mean in our lifetimes.  So what do I want to leave with all of you today?  Well, just remember, that there is no better time to start than RIGHT NOW and that though you may think you aren’t making a difference by living an environmentally friendly life, you TRULY ARE.  Now ladies and gentlemen, please excuse me while I go and attempt to practice what I have preached.

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The Substitutability of Oil and Sustainability of Our Lifestyle

This post is written by Kristen Bastug, a Junior Biology Major at St. Thomas.

All organisms need energy to survive and reproduce. Throughout the history of life, the vast majority of life-supporting energy came from the recent photosynthetic activity of plants. As we all know, humans have been able to access and exploit fossilized photosynthetic products (oil, coal, and other “fossil fuels”) to power much of modern industrial output. In just 153 years since the development of a gas-fired internal combustion engine (~1860), which allowed humans to convert fossil fuel energy into useful work on a large scale, the human population has increased ~550% and per capita GDP has grown ~875%. A cost of this fossil fuel use is the CO2 and other greenhouse gas emissions that are changing the global climate. These emissions pose an existential threat to human society, and immediate action is needed to reduce them. However, there is another problem with fossil fuel use that receives surprisingly little attention: we may be running out of it sooner than most of us realize. How likely is it that our generation will face severe shortages of fossil fuels (particularly petroleum)? What consequences would such shortages have for our current lifestyle?

Petroleum is an unbelievably cheap source of energy in terms of the amount of energy we get out from what we put in, known as the EROEI (Energy Return on Energy Invested). Energy inputs are essential in order for a species to grow, and this was traditionally done through human and animal labor. When society made the switch to fossil fuels, petroleum took the place of this labor, allowing us to pursue other endeavors and grow our society. To put things into perspective, one barrel of oil contains 1,700 kilowatt hours of energy. Humans currently consume 89 million barrels of oil per day, which is equivalent to 14,000 years of fossilized sunshine every day. In terms of human labor, it would take a person 8.6 years working 40 hours a week peddling a bicycle quickly to generate the same energy in one barrel of oil (Alexander 2011). Who wouldn’t want to pay $100 for 8.6 years of labor instead of doing it themselves?

Due to the declining production of oil fields that will make petroleum more scarce, is this form of energy a substitutable resource or an essential one? In other words, are there other forms of energy that can act in petroleum’s place without consequence? Petroleum is the dominant source of energy for transportation: 90% was supplied by petroleum products in 2011. The Bureau of Transportation reported that in 2011, 76.4% of Americans drove themselves to work every day, 9.7% carpooled, 5% used public transportation, and 2.8% walked. But oil is more connected to our lives than just at the pump. Conventional produce travels 1494 miles between when it is grown and when we buy it (Neff et al 2011), and this transport relies on petroleum to power the freight trucks. Agriculture itself depends on fossil fuels to make fertilizer; it currently takes ten calories of fossil fuels to produce one calorie of food due to the use of fertilizers and pesticides. The types of food that we consume are worth thinking about as well. It takes 600 calories of fossil energy to produce one can of diet soda, and another 1,600 calories to put it into an aluminum can. When we drink it, we get one calorie of energy out, making a “zero calorie” diet soda a 2,200 calorie fossil fuel investment. People usually think that to reduce their carbon footprint they should cut back on driving, but by eating less petroleum heavy food we can make a difference as well.

While there is debate about the exact year it will happen, there will come a time when the global production of oil cannot meet our demand. We have been developing alternative energies and the hope is that they will eventually replace oil; this would make oil a substitutable resource. Unfortunately, these alternative energies also have limits.

The most talked about type of alternative energy is Biofuel, or fuel made from plants. Biofuels are commonly thought to be the next best thing to oil. However, it takes a lot of energy input to get the fuel out, so biofuels aren’t as efficient as commonly thought.  Another problem is that they take up an enormous amount land. Land is already scarce, and biofuels will have to compete with the farmland needed to feed the future world of 9 billion people. Replacing all of the current oil with biofuel would require 232% of all the available land on the planet. Even if we wanted to substitute 60% of our oil with biofuel, we would need 140% of all arable land (Mediavilla et al 2013). This is not feasible, as much as some would like to believe that biofuels will be the major source of energy in the future.

One promising alternative to petroleum in the transportation sector is electricity. Electric vehicles are limited in that they cannot travel long distances, and cannot power heavy vehicles. This makes them unsuitable for the freight transportation sector. The Bureau of Infrastructure, Transport, and Regional economics estimates that fuel cost is currently 30% of the operating cost of freight transport. Higher oil prices will make transporting goods more expensive. Freight is essential for the distribution of food and also facilitates business, which helps drive economic growth. These cars are also limited by the metal lithium, which is currently the best element for the car battery.

We need to find a way around the limitations to current alternative energies if our society is going to make a smooth transition into the post peak oil era.  The numbers are out there, and we are currently dependent on petroleum. Knowledge about petroleum dependency and scarcity is often masked in order to avoid panic, but it is important to spread this knowledge in order to generate lifestyle changes. By understanding the inadvertent ways this resource is used, and taking responsibility for the well being of our planet by acknowledging that our lifestyles are unsustainable, we can make informed choices in our lives that reduce our carbon footprints and inspire others to do the same.

For more discussions regarding peak oil, check out The Oil Drum

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Natural World-Mississippi River Model Course, Summer 2013: Michele Goodson

Goodson Image 2

Garlic Mustard, and invasive species studied by Michele and other students.

This post was submitted by Michele Goodson, a Junior majoring in Family Studies. It is one of a series of posts regarding Dr. Lim’s Summer class, Natural World- Mississippi Model.

The Independent Study Class-Natural World-Mississippi Model, taught by Dr. Lim, has changed the way I will think and feel about the Mississippi River for the rest of my life.  I have learned more about the area of the Mississippi River and the 72 miles of park land that surround this area than I could have ever imagined. 

We studied a lot about invasive species.  Plants, animals, fish, and birds all need certain foods and a specific environment to thrive in their natural habitat.  If an invasive species enters a new habitat and takes over, it can change the entire biodiversity of the ecosystem.  Our class did a small part in helping the park service eliminate some garlic mustard, an invasive species, in Hidden Falls Park this summer. 

Goodson Image 3

We also stenciled curbs in the neighborhood near UST.  “Please don’t pollute-Drains to Mississippi River”. We visited six parks, the Metro Wastewater Treatment Plant, and the Science Museum.  All of the fieldwork we participated in was educational and made a lasting impression.

Education is the key along with action and commitment.  Think globally!  The natural resource we are so fortunate to have in our neighborhood affects more than you and me.  We can all make a difference by the little things we do every day.  

For more information and images regarding Michele’s experience, her Power Point can be viewed Here.

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This post is by Ashela Richardson, a 2013 UST Environmental Science graduate.

Pilobolus dancers (reprinted with permission)

Pilobolus dancers (reprinted with permission)

In a class this last semester called, Urban Ecosystem Ecology, I had the chance to collaborate with Pilobolus, a modern dance company.  Pilobolus’ mission is rooted in communicating science, and the interactions between humans and the environment through movement, or dance.  I participated in their choreography of a dance by contributing to discussions about environmental science with other students.  The artistic directors used the content of our discussions as inspiration for the dancers and the story of the dance.  On the first day of our collaboration, we dealt with the idea of being interconnected.  The artistic directors from Pilobolus had us push the desks aside and stand in a circle.  In a firm, but friendly voice they said:

“Secretly pick two other people, and remember who they are, but don’t say.  Now, we are going to start moving, however you feel… pick any kind of movement you want, but you must keep moving, meanwhile staying equidistant from the two people you picked.”

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Reduce Indoor Air Pollution by Increasing your Knowledge

The carpeting is beautiful but off-gassing is a concern

The carpeting is beautiful but off-gassing is a concern

Do you ever think of the air you’re breathing? Do you ever consider if it is “good air” or not? Breathing is such a casual, normal, and natural thing to do that most people never truly think about the air they breathe until it is too late. You may be making a conscious effort to improve your personal health, or the health of others by eating healthy foods, getting adequate exercise, and receiving sufficient sleep, but do you ever consider improving the air you breath? It is not something that is obvious to us, but oftentimes indoor air pollution can be much worse then that of the air outside. It only makes sense that if you have the time and drive to watch what you eat then you should consider keeping an eye on what you breathe.  There are a few steps that you can do that will control and reduce the amount of indoor air pollution in your house, simply by paying attention to the source of these pollutants.


What makes the idea of indoor air pollution hard to comprehend sometimes is that in many cases the pollutant is odorless. In many cases the items used to produce materials used in your living space are treated in certain substances that release unwanted chemicals into the air. That new “car-smell” that everyone loves is actually the off-gassing of chemicals used during the fabrication and installation of the car’s interior. In the house things such as polishes, flame-retardants, finishes, and other cosmetic substances expel these unwanted chemicals into the air. Items such as particle board (plywood, looks like a board made of wood chips) as well as other “pressed woods” contain the carcinogen formaldehyde. Formaldehyde has been linked to many cases of throat cancer… Scary. The remodeling of a house, including new carpet, releases volatile organic compounds (VOC) that can be respired by people, has also been known to cause adverse health effects. Even material goods such as shoes can off-gas harmful chemicals. They are generally treated with certain chemicals and dyes that make the shoe last longer and look prettier, but these chemicals don’t just stick with your new Nikes. They manage to make it into the air you breathe as well. All of this sounds so negative, but there is some positive in this as well. The products and materials that produce these harmful chemicals greatly decrease the in the amounts of off-gassing over time. The amount of gasses emitted by such items can be reduced by sealing exposed wood seems, or by placing newly purchased furniture outside when possible to let the harmful chemicals evaporate into the outdoor air. A quality ventilation system within the house can also greatly reduce the amount of chemicals in the air.


One of the largest sources of indoor air pollution, and possibly the most harmful is smoking. As everyone knows the harm from smoking does not only belong to that of the smoker, but the people surrounded by it as well. If you were to walk into a house of a smoker you would be able to tell right away whether or not someone in the residence smokes. The smoke produced from a cigarette does not last for only the tim it is smoked, but can linger in the room, house, and clothes for hours, days, and even years.  Where does this smoke and smell go then if it hangs around this long? The smoke and other junk produced from the cigarette finds its ways into the fabrics, drywalls, and other porous media in the house. Conveniently this is also the easiest fix of indoor air pollution. If there is a smoker in your house put a fence in the back yard, a “smoking zone” if your may, that is away from open windows so as to reduce the chances of pollution your indoor air.

Household Cleaners & Air Fresheners

I know, when reading air fresheners you need to double take. They are used to make the air smell better, and get rid of the crummy smell, but actually you may be polluting it. With household cleaners, they sometime hurt to smell, well that’s because they do. These chemically loaded cleaners may do their job at cleaning the dirty surface, but they can seriously hurt your lungs when inhaled. The limited use of both air fresheners and household cleaners should be used only when necessary. When cleaning your house make sure to breath sparingly.. not really, but keep in mind some of the chemicals you are breathing in. They can have some highly adverse effects to human health.

STOP it at the SOURCE

The Environmental Protection Agency (EPA) states that the most effective method of increasing indoor air quality and reducing indoor air pollution is cutting the pollution off at the source. What it comes down to is simply eliminating all sources of indoor air pollution, or at least reducing the emissions as much as possible.  I did not list all of the examples of source emitters, but keep an eye out for items that may produce these harmful chemicals. One last important factor to keeping your air as healthy as possible is the ability to keep your air moving. Using you’re A/C unit, or your heater and fans, keep the air moving. This will bring in “new” air, diluting the “old contaminated” air, keeping the air as fresh as possible. If you can keep an eye on you weight, what you eat, and your health, then you should have no problem keeping your air healthy as well. The air we breath is the most important element to our health. Keep an eye on what you drag into your house, be aware, and you should not have to worry about harmful air.

Conor Edwards

Conor Edwards

Conor Edwards (’13)

Environmental Science, Geology

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Ethanol: A Hindrance or Helper for Water Resources?

Cornfield_during_the_sunset!Recently, ethanol was introduced to fuel supplies as our liberator from our dependence on fossil fuels and a reducer of our input of harmful greenhouse gases into the atmosphere. It was a domestic solution to our dependence on foreign oil. Policy shifts began mandating the incorporation of ethanol into fuel sources worldwide, and they continue to mandate higher ethanol concentration in fuel sources to this day. The United States Environmental Protection Agency, for example, has mandated an increase to 36 billion gallons of biofuel production by 2022. This new standard led to the production of over 12.5 billion gallons of ethanol in 2012. Similar mandates exist in other governments, including Brazil, the European Union, India, and China. Brazil mandates current gasoline to contain 25 percent ethanol. By 2020, European Union and Chinese gasoline is mandated to contain ten and fifteen percent ethanol, respectively. Similarly, gasoline in India is mandated to contain 20 percent ethanol by 2017. Such mandates could benefit society by reducing dependence on nonrenewable energy sources. But it turns out that there are several environmental costs to biofuels, some of which are not well understood.

Adding ethanol to fuel sources has raised public concern that we might be crippling the world’s food supply. As ethanol is being mandated at higher concentrations in fuel worldwide, more and more corn crop is being diverted from the food sector for energy production ( Yet corn can account (either directly or indirectly) for up to 70 percent of an American diet. It is fed to cattle, pigs, poultry, and us. High fructose corn syrup is a staple in foods commonly found in an American diet. We are dependent on it, and as such, some argue that you cannot use corn for fuel when it is needed to feed people. Still, others link corn’s use for ethanol to higher corn prices, raising everyone’s weekly grocery bill ( Although the safety and affordability of the food supply is a major concern when considering ethanol production, an arguably greater issue gets less attention: the effect ethanol has on our water resources.

Discussion regarding ethanol’s impact on water resources typically centers on the issue of water quantity rather than water quality. For example, it is frequently mentioned that current methods for ethanol production are unsustainable and require four gallons of water to produce one gallon of ethanol, twice the amount required to produce one gallon of gasoline. However, today we transport, store, and dispense gasoline and ethanol in greater quantities and in closer proximity than ever in our history. However, little is known about what happens when these chemicals are released to the environment together.

Oil and gas spills are inevitable. They will occur and release unwanted chemicals to the water supply. In 2011, The U.S. alone consumed 370 million gallons of gasoline per day. That gasoline must be extracted from the ground, transported to refineries, sent to the pumps, and ultimately dispensed into our vehicles. While advances can be made to reduce oil and gasoline spills, they cannot be altogether avoided when so much transport is involved. Pipelines will rupture, gas trucks will spill, and storage tanks will leak. We cannot use our resources trying to prevent every possible spill. We must focus on preventing the big ones, and planning for the small ones. Resources can be better allocated to better understand how oil chemicals will act once they are release to the environment, especially in the presence of ethanol.

Gasoline contains chemicals that are known to harm human health. One suite of chemicals, benzene, toluene, ethylbenzene, and xylenes (BTEX), is known to cause cancer. If they get into a drinking water supply, that water becomes contaminated to the point of uselessness. However, with less frequent access to clean water sources, it is essential to understand and clean up contaminated water. This is where ethanol plays a huge role. Until recently, gasoline spills released just that to the environment—gasoline. Although it is true that gasoline is a blend of hundreds of chemicals, they share similar characteristics allowing their interactions in the environment to be somewhat predictable. They are insoluble in water. They tend to stick onto sediment in the ground. They are broken down, albeit slowly, by bacteria. These few generalizations allow us to predict how these chemicals will move and break down throughout the environment. However, if ethanol is spilled with these chemicals, our predictions might be wrong.

Superficially, adding ethanol to fuel sources seems like a nonissue. We are replacing some toxic chemicals with a nontoxic substitute. One might think that any such replacement would only benefit water resources. Yet it is not that simple. Ethanol may completely change the way fuel chemicals, particularly BTEX, are transported throughout the environment. Without ethanol, BTEX does not readily dissolve in water. In fact, it tends to stick onto sediments in the ground. However, BTEX dissolves in ethanol, and ethanol, in turn, dissolves in water. Prior to adding ethanol, spreading of gasoline contamination is limited by its insolubility in water; it is essentially immobile. However, by dissolving these chemicals, ethanol may increase their mobility in water, effectively multiplying the area of water contamination.

However, there is an opposing force that counteracts the spreading of contamination: the break down of chemicals by bacteria (see our video about this issue here). Bacteria can best break down gasoline chemicals like BTEX when they are dissolved in water. When stuck to sediments, they are relatively unavailable to bacteria. Because adding ethanol dissolves BTEX, it may become more susceptible to break down and consequently is more quickly removed from the environment. Additionally, bacteria prefer to break down ethanol before BTEX. This has two possible implications: 1) bacteria will consume ethanol and not degrade BTEX, or 2) the degradation of ethanol will stimulate bacterial populations that, after ethanol is consumed, will begin degrading BTEX at a faster rate due to larger bacterial populations. The interplay between these processes has not been well-characterized. It is possible that one process can dominate depending on the environment in which they occur. For example, the process dominating gasoline break down may vary from an aquifer to a wetland or lake.

Ethanol amplifies the complexities of BTEX degradation. It is possible that ethanol may spread contamination from a centralized location to one which is widespread. Alternatively, it may enhance bacterial degradation of BTEX. Both scenarios are plausible, yet the consequences are opposite. With anticipated increases in global ethanol output, we need to strive to understand these complexities so we can appropriately respond to fuel spills in order to best protect the quality of our water resources. Could ethanol increase the spreading of oil contamination to the point that we need to rethink our decision to add it to fuel sources? Or is it the ideal clean-up supplement for oil spills? Its incorporation into fuel was meant to reduce pollution to the atmosphere, but could it instead be causing greater pollution to water resources? With more research, these questions are answerable, and the answers may cause us to reconsider adding ethanol to our fuel.

Brady Ziegler

Brady Ziegler

Brady Ziegler (’13)

Environmental Science (Chemistry Concentration) and Geology

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Growing Healthy Communities

Bringing fresh, locally grown produce to corner stores in Minneapolis neighborhoods. All grown in the JRC Greenhouse at the UST St. Paul campus!

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