The Hyperloop: A Push for the Alternative is Real

Catalyst Volume 7

The drive down CA I-5 from San Francisco to L.A. takes six hours. That’s six grueling hours of negotiating the horrors of urban traffic, trying to stay awake over vast stretches of monotonous Central California farmland, and watching your gas tank guzzle your hard-earned dollars. A plane ride? A nonstop flight would take only an hour and a half, but that’s without considering the time it takes to pass through security or the price of checking in any luggage. In an age where a thought can be sent half-way around the world in mere seconds, this commute is one emphatic no-no to the time-strapped millennial American. Imagine an alternative. What if there was a way to travel this same distance in just half an hour—and for only twenty dollars a ride?

Say hello to the hyperloop.

The summer of 2013, entrepreneur Elon Musk suggested an alternative method of travel: the “Hyperloop,” a proposed form of high-speed transportation with the potential to travel up to 760 mph.¹ To put things into perspective, Japanese maglev (magnetic levitation) trains have maxed out at 361 mph, and the commercial Boeing 747 plane travels at an average of 570 mph.² The speed of sound is 767 mph. On top of it all, while the California High-Speed Rail Project is currently asking for over $68 billion dollars, Elon Musk estimates that constructing the Hyperloop would only cost $6 billion.

Subsonic speeds at one-tenth of the California High-Speed Rail Project—this audacious claim is not a first for Elon Musk, the man behind the Hyperloop. Take a look at his distinctive accomplishments as CEO and founder of the companies PayPal, Space X, and Tesla: today, the online payment service PayPal is ubiquitous; Space X is in the works of delivering its third interstellar manned vehicle prototype; and Tesla’s electric car stocks trade at over $170 a share. Clearly, Elon Musk has been the impetus behind phenomenal and successful ideas. Still, his history of successful ideas does not guarantee that the Hyperloop would be a successful project. Furthermore, Elon Musk has publicly announced that he will not be tackling the Hyperloop. However, he has released a 57 page report detailing his ideas, which are freely available for anyone to view online. Based on this information, let’s take a look at how this project might be able to work.

A brief technical breakdown

If the Hyperloop sounds like something straight out of science fiction, you wouldn’t be far from the truth. Science fiction authors have written about something that sounds very much like the Hyperloop since the 1900s. In addition to its basic design, the proposed technology for the Hyperloop has also been around for many years.

The technology behind the Hyperloop is the implementation of pneumatic action, which relies on the compression of air to induce movement. Starting in the mid-to-late 19th century, numerous major cities in the U.S. and other countries relied heavily on massive underground networks of pneumatic tubes to send mail. Although this technology has been replaced by email, pneumatic action is still at work in post offices and hospitals today. Pneumatic action is also integral to air hockey tables, which utilizes air to reduce friction. In fact, Elon Musk described the Hyperloop as a cross between a railgun, a Concorde, and an air hockey table.¹

More precisely put, the Hyperloop is a closed-tube transportation system that provides uninterrupted traffic in both directions, perhaps akin to the energy-efficient, tiny maglev pods inside of elevated tubes. This project differs from existing infrastructure developments in three predominant ways by combining a partially evacuated tube with pressure-regulating pods on elevated concrete pylons.¹ Though these features are not new, the combination of these attributes is indeed novel.

To carry passengers inside the tubes, two different distinct pod systems have been proposed: The first is an all-passenger version carrying 28 seats. The second, larger system would carry three automobiles and their passengers. No matter which system is utilized, each pod would have pressurized cabins containing backup air supply and oxygen masks in case of emergency, much like an airplane.¹

The pods would travel very fast—up to sub-sonic speeds—due to a nearly frictionless journey.¹ The steel tubes play an important role by containing a partial vacuum, one ideally one-sixth of the air pressure on Mars. Rather than relying solely on electromagnetism for the entirety of the trip, friction would also be greatly reduced thanks to electric compressor fans attached to the traveling pods.

The electric compressor fans can help overcome the Kantrowitz Limit, a limitation on mass flow related to the size ratio between pod and tube. If the space between a pod and the interior of the tube is too small, then the Hyperloop system will behave like a syringe, where the pod will push the entire column of air in the tube. The compressor fans address this problem by pushing high pressure air from the front to the rear to create a cushion of air underneath the pod.¹

To lower energy costs on the environment, the bulk of the system would be powered by a solar generator. This solar energy would be split between charging the pod batteries and the rest of the system. Musk’s plan would rev up the pods from their stations using magnetic linear accelerators resembling railguns;¹ once in the main travel tubes, the pods would be given periodic boosts by external linear electric motors similar to those in the Tesla Model S.

Finally, in order to lower the cost of construction, the partially-evacuated tubes would be elevated on concrete pylons. This type of system mitigates damage caused by earthquakes and reduces maintenance costs.¹ Additionally, elevation would allow the Hyperloop to travel without interruption, bypassing ground traffic, farmland, and wildlife. By building on pylons, the system could also follow the California I-5 highway, reducing the need for expensive land acquisition suits.

Again, these suggested attributes for the Hyperloop already exist in one form or another, but they have not yet been combined in such a manner. For instance, much of the Federal Highway System uses concrete pylons to elevate interwoven freeways. The subways of New York City and Chicago are enclosed systems, but they do not run on cushions of airs. Maglevs run on a cushion of air, but they are not enclosed.

So what does this mean?

All in all, the scientific community generally seems to agree that the Hyperloop is technically feasible. However, Elon Musk’s proposal does come with many caveats. The most significant problems seem to stem from economic and political concerns. Critics have claimed that Elon Musk’s idea is overtly conceptual and utilizes unrealistic cost estimations. The estimations are particularly contentious because the Hyperloop proposal is reminiscent of the California High-Speed Rail, a project with initial estimates that were much lower than the current budget; in 2008, state voters had approved $9.91 billion dollars for the California High-Speed Rail Project. By April 2012, High-Speed Rail estimates had reached $91.4 billion, nearly ten times original estimates, before public outcry triggered a budget revision.

However, the Hyperloop manages to avert many of the same issues plaguing the California rail project. One benefit of building on concrete pylons is a reduction in land acquisition, currently the most expensive and politically contentious issue affecting transportation projects. Another benefit of the project is an independence from federal funding. Without a reliance on bond measures or public coffers, the Hyperloop would not need to build in potentially unprofitable areas to keep policymakers satisfied. Free from political strings, it could focus on creating a profitable, sustainable venture.

Regardless of the advantages, it seems unlikely that construction on the Hyperloop following the proposed route between San Francisco and Los Angeles would begin during the construction of the California High-Speed Rail. This is unfortunate, as a route between L.A. and San Francisco guarantees a customer base. Furthermore, city pairs that are 120 to 900 miles apart are ideal for rail or similar transportation, as this distance is too far to comfortably travel by car and yet too close to efficiently travel by plane.⁷ L.A. and San Francisco fit perfectly in that niche.

Elon Musk has not made any plans to develop the Hyperloop, causing many to believe that the entrepreneur may be using the Hyperloop as an elaborate red herring. One critic has pointed out that the construction of the California High-Speed Rail would directly compete with automobiles in Silicon Valley, one of Tesla’s target market demographics. Could Musk trying to derail the already tenuous rail initiative in order to reduce economic competition? Interestingly, after the official Hyperloop press release, local politicians in the Silicon Valley area lobbied to prevent the California High-Speed Rail from developing in their respective constituent zones. Was this mere coincidence?

Regardless, the most valuable attribute of the Hyperloop project is its status as an open-source engineering project open to privatization. Using the same basic principles, one man has even built a working miniature prototype with the capacity to hover on a cushion of air. Autodesk, a 3D design software, has produced realistic, promotional renderings of the Hyperloop. ET3 is a company that is working on similar evacuated vacuum tube designs.³ In this day and age, crowdfunding platforms like Kickstarter and microfunding organizations like Kiva could potentially be used to financially support the construction of the Hyperloop. In the Netherlands, the company Windcentrale raised over 1.3 million Euros in only thirteen hours from 1700 Dutch households eager for a local wind turbine.⁵ Money for the Hyperloop could be similarly raised.

Whatever the case, one thing is clear: even if the Hyperloop remains a conceptual project, the idea has opened up an important dialogue regarding the future of mass transportation in America. It has bought attention to the inefficiencies of the California High-Speed Rail Project, and it has renewed interest in technological advances for public transportation. The Hyperloop might also lead the U.S. towards privatized or crowdfunded infrastructure. Perhaps most importantly, the buzz around the Hyperloop has reaffirmed the need for alternative transportation.

References

1. Musk, Elon. Hyperloop Alpha. https://www.teslamotors.com/sites/default/files/blog_images/hyperloop-alpha.pdf (accessed Oct 20, 2013).
2. 747 Family. http://www.boeing.com/boeing/commercial/747family/background.page (accessed Nov 4, 2013).
3. “The Evacuated Tube Transport Technology Network.” ET3, 24 Oct. 2013. <http://et3.net/>.
4. United States Bureau. The California Energy Commission. California Gasoline Statistics & Data. Energy Almanac. Web. 30 Oct. 2013. <http://energyalmanac.ca.gov/gasoline/>
5. “Dutch Wind Turbine Purchase Sets World Crowdfunding Record.” Renewable Energy World. Ed. Tildy Bayar. 24 Sept. 2013. Web. <http://www.renewableenergyworld.com/rea/news/article/2013/09/dutch-wind-turbine-purchase-sets-world-crowdfunding-record>.
6. “2012 Annual Urban Mobility Report.” Urban Mobility Information. Texas A&M Transportation Institute. Web. 11 Oct. 2013. <http://mobility.tamu.edu/ums/>.
7. “Competitive Interaction Between Airports, Airlines, and High Speed Rail.” Joint Transport Research Centre. Paris. Discussion Papers.7 (2009): 20. 8 Dec. 2013.
8. Central Intelligence Agency. The World Factbook. n.d. Web. 18 Nov. 2013. <https://www.cia.gov/library/publications/the­world­factbook/>.
9. Levinson, David. “Density and Dispersion: the Co­development of Land use and Rail.” London Journal of Economic Geography, 8 (1), 55­77. 10.1093/jeg/lbm038. 2007.

Hands-free driving: A Roadmap to the Future

Catalyst Volume 7

The simple act of driving can be an unproductive, dangerous, and time consuming activity, one that can be solved through the installation of autonomous technology within vehicles. This technology is considered to be among the most crucial breakthroughs in human travel that is being developed today; it is believed to have the capacity to create an improved and efficient driving experience by limiting fuel consumption, decreasing traffic congestion, and reducing wasted time during road trips.

One of the driving forces behind the creation of autonomous vehicles is safety. Autonomous technology promises safer travel compared to human-operated vehicles, as the cars are equipped with laser and video detection systems to control the car's speed and steering mechanisms while avoiding obstacles in the roadway. This blend of autonomous technologies promises to make driving 99% safer while also allowing the travelers to focus on other activities.¹

These cars must detect and make rapid decisions to avoid objects in the roadway; the simple act of crossing an intersection requires the robotic cars to account for the inertias, right-of-way, and velocity of approaching vehicles.² A major problem facing autonomous vehicles is the idea of real-time communication. As humans correspond face-to-face, these autonomous cars need to interact in real-time, allowing the cars to work together safely. However, this type of communication is unpredictable and extremely hard to maintain.³ Autonomous technology presents near endless benefits to automobile commuters; however, this technology faces not only current mechanical and software problems but also major legal and social issues. This technology needs to be perfected in every way possible before being released into city streets. Through my review of the autonomous technology within these computer-driven cars, I will explore the type of technology that operates these cars, how it operates the vehicle, the benefits created from this technology, and any possible legal and social concerns that arise from their use.

Developing Technologies: Seeing, Thinking, Steering

The ability for autonomous cars to see and judge risks in the roadway is vital to safe operation of the vehicle. An outstanding prototype of autonomous technology was created in 2007 by the Stanford Racing Team. Their robotic car Stanley, which won the DARPA Grand Challenge, operated solely on a software system that processed and converted visual data into appropriate driving commands.⁴ This software system uses an onboard sensors including lasers, cameras, and radar instruments to gather outside information from the road, allowing the robotic vehicle to observe and judge the approaching roadway;⁴ these sensors are placed on top of the vehicle. The combination of lasers and cameras allows for increased detection of obstacles by allowing both short and long range detection, respectively.⁴ As the cameras receive the long range images, the lasers allow the vehicle to detect the dimension of approaching objects that could harm the vehicle. Detection of hazardous obstacles is one of the easier aspects of autonomous driving; split second decision-making based on the detection system is harder to accomplish. An autonomous vehicle must use the information from the detection systems to determine if the road surface is safe for driving. Measuring the dimensions of detected objects allows the car to determine if they are true obstacles, such as roadway debris, or non-obstacles, such as grass and gravel. The researchers who helped build Stanley stated that the robot had trouble determining the difference between tall grass and rocks, which poses obvious difficulties in application.⁴ In addition to obstacle recognition software, autonomous vehicles require extensive algorithms to accomplish and maintain velocity, steering, acceleration, and braking—functions all controlled by the same system of detection and decision making.

Dynamically Guided Routes

Route guidance is core to autonomous vehicle technology, which is not safe and effective without a computed path. The purpose of route guidance is to gather information from outside sources (e.g. other vehicles, fleet signals) and stored data to create the most efficient route. However, this technology is hindered by the limited amount of information that can be stored within the vehicle due to static map conditions.⁵ Static conditions are defined as the basic components of individual roadways, such as the length of the road, speed limit, and pre-existing intersection signals. Using static systems can result in unreliable and slower routes due to an inability to account for dynamic road situations; for example, these static routes can be highly ineffective once an accident occurs on the roadways.

Generating accurate routes while on the road is another computationally challenging problem for autonomous technology.⁵ Due to the mobile condition of autonomous vehicles, current onboard computational power cannot compute and translate both long algorithms and dynamic conditions at the same time. Researchers attempting to create an algorithm must balance quick execution and efficient route creation with low computational power.

An additional problem arises from dynamic roadways. Dynamic roads are defined as streets that are always changing due to traffic jams, accidents, and construction.⁵ In his article on route guidance, Yanyan Chen stated that a good route is one that, although possibly not the fastest, is both reliable and acceptable to the driver’s needs. As a solution, Chen and his team created the Risk-Averse A' Algorithm (Figure 1). This algorithm suggests a risk-averse strategy that pre-computes factors that affect traffic (such as weather and time of day), accounts for dynamic traffic flow and accidents, and computes a low-risk and reliable route. The Risk-Averse A' Algorithm is widely accepted in the field of autonomous research as the most efficient form of computing reliable and adaptive directions. In fact, Stanley used this algorithm in the DARPA Challenge.⁴

Navigating Intersections Proves Difficult

The task of navigating an autonomous car through an intersection is not simple. The vehicles must be able to use algorithms to derive not only the distance from the car to the intersection but also its current inertia. Simultaneously, this information must be constantly compared with that of other vehicles. The two main challenges in crossing an intersection are establishing reliable communication with other vehicles as well as the dynamic, convoluted environment of intersections. For autonomous navigation to be possible, vehicles must communicate with each other to determine which car has right of way. When approaching an intersection, each car should propagate signals to the other vehicles, a failsafe in case oncoming cars are not detected by the visual and laser system (Figure 2). In theory, autonomous vehicles will discharge signals containing position and velocity information. At an intersection, approaching cars can detect and process this information to determine the appropriate mechanical move.

The dynamic environment of an intersection creates a whole new series of problems with the introduction of unknown variables. An autonomous system must be able to adapt, sense, and make decisions in short periods of time. The proposed ideas on how to navigate intersections use a decentralized navigation function, a method that has no need for long-range communication between vehicles. It enables cars to navigate independently while maintaining network connectivity and an overall goal. This function allows the car to account for dynamic traffic and improves the use of algorithms.²

Robotic Communication

The problem of real-time coordination between vehicles is a major obstacle that must be overcome for this technology to function safely on city streets and highways. Without reliable and fast communication, autonomous vehicles cannot navigate intersections, conserve energy, drive in safe formations, or create efficient routes. However, communication through wireless networks is not always reliable. Dr. Mélanie Bouroche from Trinity College, Dublin, stated that a “vehicle intending to cross an un-signaled junction needs to communicate in an area wide-enough to ensure that other vehicles … will receive its messages.”³ Figure 3 illustrates how the cars should disperse signals to communicate with other vehicles.

In the article “Real-Time Coordination of Autonomous Vehicles,” Bouroche, Hughes, and Cahill found a solution to this communication issue by creating a space-elastic communication model. A coordination model for autonomous cars allowed autonomous vehicles to adapt their behavior depending on the state of communication, ensuring safety constraints were never violated.³

Conclusion

Autonomous technology should improve daily travel by decreasing fuel consumption, traffic congestion, and accidents. The construction of new highways and streets to accommodate this technology would modernize and improve the efficiency of cities. Daily life could be enhanced, as driving time could be spent more productively. Autonomous technology can greatly improve everyday vehicular travel—but only if it is correctly implemented into society. Many problems still remain in the realization of autonomous vehicles: detection systems must be improved to effectively identify and avoid obstacles, algorithms need to be refined to quickly compute dynamic routes, and communication between vehicles needs to be drastically improved in order to avoid accidents. The legal and societal issues must also be addressed: will all vehicular travel be converted to automated travel? If so, will all citizens be forced to use technology that controls their movement? If not, will separate highways and roads be built? Who will fund this new creation of streets and roads? Who will ultimately control and maintain such a system? Autonomous technology has the potential to vastly improve travel, but it can introduce system vulnerabilities and malfunction. Self-directed vehicles must be thoroughly researched and tested before the technology can be implemented on city, state, and national streets.  

References

1. Hayes, B. Am. Sci. 2011, 99, 362-366.
2. Fankhauser, B. et al. CIS 2011: IEEE 5th International Conference, Qingdao, China, Sept 17-19, 2011; pp.392-397.
3. Bouroche, M. et al. IEEE Conference on Intelligent Transportation Systems, 2006, 1232-1239.
4. Thrun, S. et al. J. Field Robot. 2006, 23, 661-692.
5. Chen, Y. et al. J. Intell. Transport. S. 2010, 14, 188–196.
6. Bergenhem, C. et al. Sartre, 2008, 1-12.
7. Dahlkamp, H. et al. In Proceedings of the Robotics Science and Systems Conference, 2006, 1-7.
8. Elliott, C. et al. In The Royal Academy of Engineering, 2009, 1-19.
9. Douglas, G. W. Unmanned Systems, 1995, 13, 3.
10. Laugier, C. et al. In Proceedings of the IFAC Symposium on Intelligent Autonomous Vehicles. 2001, 10-18.
11. Wright, A. Comm. ACM 2011, 54, 16-18. 

Do You Know Your Bottled Water?

Catalyst Volume 7

Nearly 54% of the American population drink bottled water.¹ As they pick up packages of plastic-wrapped bottles off the shelf, they may believe the water within is cleansed of toxic chemicals, free of bacteria, and enhanced with minerals. In truth, bottled water is just as likely to have the same level of harmful chemicals as that of tap water, contain between 20,000 to 200,000 bacterial cells, and lack any beneficial minerals depending on water source.²

As sales of bottled water increase, consumption of tap water decreases.³ Since 1999, the average world consumption of bottled water has increased by 7% each year based on annual per capita,⁴ now surpassing the sales of milk and beer.⁵ This growing habit is costly to both the wallet and environment. Companies price bottled water 500 to 1,000 times higher than tap water on average,⁴ and producing one bottle of water requires 1,000 to 2,000 times more energy than producing the same amount of tap water—in addition to producing plastic waste.⁵ Are these increased costs justified by the belief that bottled water is safer or cleaner than tap water? In reality, that perception is a marketing myth.

Contrary to popular belief, bottled water is held under lower safety standards than tap water is. There are two different groups regulating drinking water: the Food and Drug Administration (FDA) oversees bottled water and the Environmental Protection Agency (EPA) regulates tap water. In setting health standards, the FDA follows the footsteps of the EPA. The EPA is the first to set limits on dangerous chemicals, biological wastes, pesticides, and microbial organisms in tap water, and the FDA then adopts those limits for bottled water. As a result, regulations on bottled water are no stricter than those on tap water. In fact, they are often weaker. Table 1 lists health standards that differ between bottled and tap water; bottled water only has stricter limits on copper, fluoride, and lead.

The higher lead level of 15 parts per billion (ppb) in tap water allowed by the EPA—three times the limit for bottled water—may alarm some, but research indicates lead exposure at 15 ppb does not elevate blood lead levels in most adults. When the FDA followed suit to establish a lead limit in bottled water, it lowered the limit to 5 ppb because the majority of bottled water manufacturers could reasonably reach that level.⁶ Bottled water does not need to travel through pipes made of lead, so a stricter limit is sensible and could only be beneficial.

Unfortunately, FDA standards are poorly enforced. Water that is bottled and sold within the same state is not covered by FDA rules: an estimated 60-70% of bottled water sold in the United States meet the criteria of being intrastate commerce and thus are only regulated by the state.⁶ A survey revealed that most states spend few, if any, resources policing bottled water, so compliance with standards for more than half of the bottled water on grocery shelves is discretionary.⁶ With overall weaker health standards and lax enforcement of regulation, bottled water is not obligated to be safer than tap water. How does the quality of bottled and tap water compare in reality? Examination reveals differences in their mineral content and microbial content that impacts personal health.

Mineral Comparison

In terms of mineral composition, the amount of mineral content in bottled and tap water largely depends on source and treatment. Bottled water can be designated as spring, mineral, or purified. Spring water, including brands such as Ozarka^® and Arrowhead^®, originate from surface springs with water flowing naturally from underground supplies. Mineral water is simply spring water with at least 250 parts per million (ppm) of dissolved minerals such as salts and metals.³ Purified water brands such as Aquafina^® and Dasani^® take water from either underground or tap water sources and filter it to remove all minerals.

Tap water is more simply categorized as being sourced from surface water or ground water. Surface water refers to lakes, rivers, or oceans, while ground water describes any reservoir located beneath the earth's surface. For example, most of the tap water in Houston, Texas originates from a single surface water source.³ The source of any drinking water affects which minerals ultimately remain in the drinking water.

Three specific minerals important for a healthy body are calcium, magnesium, and sodium. Adequate calcium intake is important to maintain and restore bone strength for the young and to prevent osteoporosis in the old. Insufficient consumption of magnesium has been associated with heart disease including arrhythmias and sudden death.³ On the other hand, overly high sodium intake is well associated with high blood pressure and death from heart disease.⁷ The intake of all three of these minerals can be ensured by drinking water high in calcium, high in magnesium, and low in sodium. In fact, magnesium in water is absorbed approximately 30% faster than magnesium in food.³

A comparative study in 2004 examined these three minerals in bottled and tap water across major U.S. regions. It concluded that drinking two liters per day of tap groundwater water in certain regions or bottled mineral water of certain brands can significantly supplement a person’s daily intake of calcium and magnesium (Table 2).³ To obtain mineral data, the study contacted tap water authorities in 21 different cities spanning the U.S. and obtained published data for 37 North American brands of commercial bottled water. While tap water sources showed wide variations in calcium, magnesium and sodium content, mineral levels of bottled water were more consistent from category to category. In general, tap water from groundwater sources had higher levels of calcium and magnesium than those from surface water sources. High levels of calcium correlated with high levels of magnesium, while sodium levels varied more independently. Out of 12 states, water mineral levels were highest in Arizona, California, Indiana, and Texas. In half of the sources from those states, two liters of tap water allow adults to fulfill between 8 - 16% of calcium and 6 - 31% of magnesium daily recommended intake (DRI). Additionally, more than 90% of all tap water sources contained less than 5% of sodium DRI in two liters.

Amongst the bottled waters, spring water consistently contained low levels of all three minerals, while mineral waters contained relatively high levels of all three minerals (Table 2). Ozarka^® spring water, produced in Texas, provides less than 2% of the three minerals' DRIs. In contrast, one liter of Mendocino^® mineral water supplies 30% of the calcium and magnesium DRIs in women, and one liter of Vichy Springs^® mineral water provides more than 33% of the recommended maximum sodium DRI. Based on these percentages, drinking bottled “mineral” as well as tap water from groundwater sources in certain cities can supplement food intake to fulfil calcium and magnesium DRIs.

Microbial Comparison

Despite labels depicting pristine lakes and mountains, bottled drinking water nearly always contains living microorganisms. In general, processing drinking water serves to make the water safe—not necessarily sterile. The FDA and EPA only regulate bottled and tap water for coliform bacteria, which are independently harmless but indicate the presence of other disease-causing organisms.¹ E. coli are an example of coliform bacteria that reside in the human and animal intestines and are widely present in drinking water.⁸ The total amount of microorganisms in water is often measured by incubating and counting the colony forming units (CFU), or bacteria that develop into colonies. Water with under 100 CFU/mL indicates microbial safety, while counts from 100-500 CFU/mL are questionable.⁸

In 2000, a research group compared the microbial content of bottled and tap water by obtaining samples from the four tap water processing plants in Cleveland, Ohio and 57 samples of bottled water from a number of stores.⁹ The bottled water samples included products classified as spring, artesian, purified, and distilled. Bacteria levels in the bottled waters ranged from 0.01 to 4,900 CFU/mL, while the tap water samples varied from 0.2 to 2.7 CFU/mL.⁹ More specifically, 15 bottled water samples contained at least 10 times as much bacteria as the tap water average, three bottled water samples contained about the same amount of bacteria, and 39 bottled water samples possessed less bacteria. As shown in Figure 1, one-fourth of the samples of bottled water, mainly spring and artesian water, had more bacteria than tap water, demonstrating that bottled water is not reliably more clean of bacteria than tap water. The bacteria in both bottled and tap water can cause gastrointestinal discomfort or illness.¹⁰

What is the Healthiest and Cleanest Water to Drink?

Since bottled water and tap waters contain varying levels of microbes, clean water is most reliably obtained by disinfecting tap water with commercially available water purifiers. Most purifiers also act as filters to remove chlorine, its byproducts, and other harmful chemicals that accumulate in tap water. However, chemical-removing filters will also remove any calcium and magnesium present as well, so purified tap water loses its mineral benefits. The loss of aqueous mineral intake can be overcome by eating foods rich in calcium and magnesium; maintaining mineral DRIs will result in a better level of health and energy. Bottled water is not guaranteed to be cleaner than tap water, so drinking properly filtered tap water may be the most economic and health way for hydration.

References

1. Rosenberg, F. A. Clin. Microbiol. Newsl. 2003, 25, 41–44.
2. Hammes, F. Drinking water microbiology: from understanding to applications; Eawag News: Duebendorf, Switzerland, 2011.
3. Azoulay, A. et al. J. J. Gen. Intern. Med. 2001, 16, 168–175.
4. Ferrier, C. AMBIO 2001, 30, 118–119.
5. Gleick, P. H.; Cooley, H. S. Environ. Res. Lett. 2009, 4, 014009.
6. Olson, E. D. et al. Bottled Water: Pure Drink or Pure Hype?; NRDC: New York, 1999.
7. Chobanian, A. V; Hill, M. Hypertension 2000, 35, 858–863.
8. Edberg, S. C. et al. J. J. Appl. Microbiol. 2000, 88, 106S–116S.
9. Lalumandier, J. A.; Ayers, L. W. Arch. Fam. Med. 2000, 9, 246–250.
10. Payment, P. et al. Water Sci. Technol. 1993, 27, 137–143

Farming the Unknown: The Role of the Livestock Industry in Preserving Human Health

Catalyst Volume 7

The livestock industry is a vast network of expectations. A farmer expects meat, dairy, and eggs from his animals, and a consumer expects to obtain these products from grocery stores. Industry expects profitable revenue from the sales of these products. Given the intensiveness of modern agriculture, this chain of action has been massively amplified. Meat production has doubled since the 1950s, and currently almost 10 billion animals—not including additional goods such as dairy and eggs—are consumed every year in the United States alone.¹ Due to the magnitude of this industry, even small changes can bring about large scale effects. Infections exemplify this chain of events.

Though animal infections might initially seem to be a lesser concern, their effects on human health are rapidly becoming more pronounced and pervasive. During the past few years, an increased number of food-borne disease outbreaks have been traced to products such as beef, pork, poultry, and milk.² These outbreaks are especially concerning because the pathogens involved are new strains previously harmless to humans. Rather, these pathogens have become infectious to humans due to mutations that occur in animal hosts; such diseases that jump from animals to humans are termed zoonotic. Within the food industry, zoonotic illnesses can be transmitted by consumption or through contact with animals. Crucially, zoonotic cases are much harder to treat because there is no precedent for their treatment.

How often does this transmission occur? Since 1980, 87 new human pathogens have been identified, out of which a staggering 80% are zoonotic.³ Furthermore, many of these have been found in domestic animals, which serve as reservoirs for a variety of infectious agents. The large number of zoonoses raises several key questions. Are these outbreaks the product of our management of livestock or simply a natural phenomenon? How far could zoonotic illnesses escalate in terms of human cases and mortality? What practices or perspectives should we modify to prevent further damage?

Prominent virologist and Nobel laureate in medicine Sir Frank MacFarlane Burnet provided a timeless perspective to this issue in the mid-20th century. He conceptualized infectious disease as equally fundamental to other interactions between organisms such as predation, decomposition, and competition.⁴ Taking into account how we have harnessed nature, particularly with the aim of producing more food, we can see how farming animals has also inadvertently farmed pathogens.

Treating animals as living environments that can promote pathogenic evolution and diffusion is crucial to creating proper regulations in the livestock industry that protect the safety of consumers in the long run. Current practices risk the emergence of zoonotic diseases by facilitating transmission under heavily industrialized environments and by fostering antibiotic resistance in bacteria. Cooperative action between government, producers, and educated consumers is necessary to improve current practices and preserve good health for everyone.

Influenza: Old Threats, New Fears

The flu is not exactly a stranger to human health, but we must realize that the influenza virus not only affects humans but also other species such as pigs and birds. In fact, what is known as “the flu” is not a single virus but rather a whole family of viruses. The largest family of influenza viruses, influenza A, has different strains of viruses classified with a shorthand notation for their main surface glycoproteins –H for hemagglutinin and N for neuraminidase (Figure 1). These surface glycoproteins are important because their structure and shape determines if the virus will attach to the cellular receptors of its host and infect it. For example, the influenza H7N7 virus has a structure that allows it to specifically infect horses but not humans. Trouble arises when these surface glycoproteins undergo structural changes and the virus gains the capacity to infect humans, as was the case during the 2003 avian flu and the 2009 swine flu pandemics, when the influenza virus jumped from poultry and swine to humans.

Since 2003 when it was first documented in humans, avian influenza H5N1 has been responsible for over 600 human infections and associated with a 60% mortality rate due to severe respiratory failure.⁵ The majority of these cases occurred in Asia and Africa, particularly in countries such as Indonesia, Vietnam, and Egypt, which accounted for over 75% of all cases.^5-6 Though no H5N1 cases have been reported in the U.S., there have been 17 low-pathogenicity outbreaks of avian flu in American poultry since 1997, and one highly pathogenic outbreak of H5N2 in 2004 with 7,000 chickens infected in Texas.⁵

Poultry is not the only area of livestock industry where flu viruses are a human health concern. The 2009 outbreak of influenza H1N1—popularly termed “swine flu” from its origin in pigs—was officially declared a pandemic by the WHO and the CDC. With an estimated 61 million cases and over 12,000 deaths attributed to the swine flu since 2009, H1N1 is an example of a zoonotic disease that became pandemic due to an interspecies jump that turned it from a regular pig virus to a multi-species contagion.⁷

The theory of how influenza viruses mutate to infect humans includes the role of birds and pigs as “mixing vessels” for mutant viruses to arise.⁸ In pigs, the genetic material from pig, bird, and human viruses (in any combination) reassorts within the cells to produce a virus that can be transmitted among several species. This process also occurs in birds with the mixing of human viruses and domestic and wild avian viral strains. If this theory is accurate, one can infer that a high density of pigs in an enclosed area could easily be a springboard for the emergence of new, infectious influenza strains. Thus, the “new” farms of America where pigs and poultry are stocked to minimize space and maximize production provide just the right environment for one infected pig to transfer the disease to the rest. Human handlers then face the risk of exposure to a new disease that can be as fatal as it is infectious, as the 2009 swine flu pandemic and the 2003 avian flu cases demonstrated. As consumers, adequate care of our food sources should not only be priority in avoiding disease but also in national and global health.

Feeding our Food: Antibiotic Resistance in the Food Industry

Interspecies transmission is not the only way through which new diseases can become pathogenic to humans. In the case of bacteria, new pathogenic strains can arise in animals from the action of another mechanism: antibiotic resistance. Antibiotic resistance is the result of the fundamental concept of evolutionary biology—individuals with advantageous traits that allow survival and reproduction will perpetuate these traits to their offspring. Even within the same population, antibiotic resistance varies among individual bacteria—some have a natural resistance to certain antibiotics while others simply die off when exposed. Thus, antibiotic use effectively selects bacteria with such resistance or, in some cases, total immunity. In this way, the livestock industry provides a selective environment.

The rise of these resistant strains—commonly termed “superbugs” for their extensive resistance to a variety of common antibiotics—has been a serious threat in hospitals; there, antibiotic use is widespread, and drug resistance causes almost 100,000 deaths each year from pathogens such as Methicillin-resistant Streptococcus aureus, Candida albicans, Acenitobacter baumanni, and dozens of other species.⁹ Our attention should not be exclusively focused to hospitals as sources of superbug infections, however. The widespread use of antibiotics in the livestock industry to avoid common bacterial diseases in food animals also poses the risk of emerging superbug strains, and it has not been without its share of outbreaks and casualties.

The Center for Science in the Public Interest –a non-profit organization that focuses on advocating for increased food safety in the US—has reported that antibiotic-resistant pathogens have been the cause of 55 major outbreaks since 1973, and that the majority of cases have come from dairy products, beef, and poultry. Furthermore, the same study reported that most of these pathogens exhibit resistance to over 7 different antibiotics.¹⁰ One of the main culprits identified in these outbreaks is the bacterium Salmonella typhimurium along with other Salmonella species, which account for over half of these cases. Salmonella is especially dangerous because it is so pervasive; it is able to lay dormant in a variety of livestock products such as uncooked eggs, milk, cheese, poultry, and beef until incubating in a live host for infection. Escherichia coli 0157:H7 (commonly known as E. coli), a bacterium that usually resides in the intestines of mammals, has also been implicated in a number of outbreaks related primarily to beef products. Overall, antibiotic-resistant pathogens have been the cause of over 20,500 illnesses, with over 31,000 hospitalizations and 27 deaths.¹⁰

These cases demonstrate how the widespread use of antibiotics in the food industry is perpetuating the risk of infections and damage to human health with antibiotic-resistant bacteria. Currently, the Food and Drug Administration (FDA) in the U.S. still approves of the use of antibiotics as a treatment for sick animals; furthermore, the organization allows antibiotic use in healthy animals as prevention and even as growth enhancers.¹¹ In fact, over 74% of all antibiotics produced in the United States are used in livestock animals for these reasons.^9,11 Using antibiotics in non-infected animals in this way generates a greater environmental pressure for superbugs to emerge; this type of use in particular should be restricted. Managing a proper use of antibiotics to reduce the risk of emerging strains of superbugs should be prioritized in the food industry just as it is in health care.

Hungry for a Solution

Still open to debate is the question of how many resources should be allocated to the problem of widespread antibiotic use. Currently, diseases are transmitted from animals to humans faster than they are evolving within humans. Not only that, many of these zoonotic diseases have high potential to become a pandemic due to their high infectivity, as in the case of H5N1 avian influenza. Measures to prevent the transmission of viruses among livestock animals and to reduce the rate of emergent antibiotic-resistant strains need to take into account the environmental and evolutionary nature of a zoonosis.

A more thorough surveillance of livestock animals and monitoring signs of new emerging strains are important in preventing the spread of such deadly pathogens. This strategy requires intensive molecular analysis, a larger number of professionals working in the field, and a nationwide initiative. Keeping an accurate record of where new strains arise and the number of animal and human cases would significantly improve epidemiological surveillance of infectious disease. This process requires cooperation at multiple levels to ensure that the logistics and public support for these initiatives is ongoing and effective. Additionally, educating people about the nature of zoonotic pathogens is crucial to fostering the dialogue and action necessary to secure the good health of animals, producers, and consumers.

References

1. John’s Hopkins Center for a Livable Future: Industrial Food Animal Production in America. Fall 2013. http://www.jhsph.edu/research/centers-and-institutes/johns-hopkins-center-for-a-livable-future/_pdf/research/clf_reports/CLF-PEW-for%20Web.pdf (accessed Oct 24, 2013).
2. Cleaveland, S. et al. Phil. Trans. R. Soc. B. 2001, 356, 991.
3. Watanabe, M. E. BioScience 2008, 58, 680.
4. Burnet, F. M. Biological Aspects of Infectious Disease. Macmillan: New York, 1940.
5. Centers for Disease Control and Prevention: Avian Flu and Humans. http://www.cdc.gov/flu/avianflu/h5n1-people.html. (accessed Oct 12, 2013)
6. Cumulative number of confirmed human cases of avian influenza A(H5N1) reported to WHO. http://www.who.int/influenza/human_animal_interface/H5N1_cumulative_table_archives/en/ (accessed March 14, 2013)
7. Chan, M. World Now at the Start of the 2009 Influenza Pandemic. http://www.who.int/mediacentre/news/statements/2009/h1n1_pandemic_phase6_20090611/en/ (accessed March 14, 2013).
8. Ma, W. et al. J. Mol. Genet. Med. [Online] 2009, 3, 158-164.
9. Mathew, A. G. et al. Foodborne Pathog. Dis. 2007, 4, 115-133.
10. DeWaal, C. S.; Grooters, S. V. Antibiotic Resistance in Foodborne Pathogens. http://cspinet.org/new/pdf/outbreaks_antibiotic_resistance_in_foodborne_pathogens_2013.pdf (accessed March 14, 2014).
11. Shames, L. Agencies Have Made Limited Progress Addressing Antibiotic Use in Animals http://louise.house.gov/images/user_images/gt/stories/GAO_Report_on_Antibioic_Resistance.pdf. (accessed Jan 20, 2014).