Giving a crap about taking a crap

What's that smell?

It's everyone's favorite topic to skirt, that topic that's discussed only when talking about cleaning up after the dog, or kitten, or baby. What is it? Poop! While there are a variety of names for it in many languages--feces, kaka, crap, etc.-- it's something that's rarely ever talked about. I mean, how often do you think about where your last lunch went after you flushed it down the drain? Probably never. And what's the worst-case scenario for you when you really have to go? Someone forgetting to put the seat up or down?

Well, what IS the worst-case scenario for the rest of the world? Probably a lack of a toilet in the first place. No, not a lack of a flushing toilet, but literally people doing their business wherever they please because no structure, hole, or anything else is available. An estimated one-third of the world's 2010 population lacked access to a toilet according to the Joint Monitoring Program of the World Health Organization, United Nations, and UNICEF. Numbers for some of the poorest areas of the world, including sub-Saharan Africa and South Asia, get as high as 70% lacking access to suitable toilet facilities. This becomes a problem when talking about stopping the spread of disease-causing microbes in the environment.

Onto a lesser thought-of question...

Where does that stuff go after I flush it?

For those in the United States, most of our solid waste (poop) is sent in water to a wastewater treatment plant, where it is treated to kill microbes present, then released. While we may think we have the resources (read: clean water) to deal with our crap, we do have to worry about where our waste goes and the resources used to process it and make it safe. It isn't a reality for us or the rest of the world to expect new, clean water to continuously be available for our sanitary systems. Additionally, a lot of nutrients and minerals that are consumed by animals have been shown to be limited in quantity throughout the world. We simple don't have an unlimited source of certain materials that we both use and consume.

How does this relate to your own poop? Well, our bodies, while amazing at many things, are far from 100% efficient at using the nutrients in the food that we consume. Thus, our stool contains nutrients and minerals that comes from plants and animals that we eat--that is, nutrients that came from our environment and could possibly be returned to that environment. The recycling of these nutrients back into agriculture or the environment is the idea of Ecological Sanitation or "EcoSan."

Gross! I want to use a toilet, I'm not just going to do 'it' on the ground! That's unclean!
EcoSan uses toilets. The idea is that you have a Port-o-Potty of sorts, except instead of the poop just sitting there, it is covered with husk or other plant material in a barrel under you. This allows the fresh stool to start to compost--that is, chemically and biologically break down to generate usable nutrients for fertilizer. Once the barrel is full, it's replaced. Generally, the full barrels are collected regularly and brought to a composting site where they can be dumped into bins, introducing oxygen into the composting process and allowing the piles to heat up.

"Fresh" compost pile in Port-au-Prince, Haiti

Do I urinate into this as well? 
Nope! Urine is generally diverted (like a small urinal inside the toilet) to be collected in a separate jug (see below). It provides a valuable source of nitrogen for the future fertilizer!

Urine collected in jugs to be added to compost piles

Is it safe?
Yes, when done correctly, EcoSan produces a safe final compost product that is essentially fertilizer for future farming. There are a variety of ways to kill off the nasty bacteria, viruses, and parasites that you might worry about in there. When the poop/husk/plant material combination is assembled into piles off-site, it heats up due to the decaying process. This temperature can get over 160 degrees, high enough to kill even the hardiest microbe if sustained long enough. Other ways? Well scientists have determined that adding ash or lime (the powdered kind, not the citrus!) can speed the death of the microbes. Drying is another process unfriendly to microbes that live in feces. After several months of composting, all microbes are generally dead and the fertilizer is ready, though these methods can speed up microbe die-off to requiring only days.

What's the catch?
There are 3 catches: compost quality, the size of the operation, and its acceptability. While drying compost and/or adding lime or ash may hasten the death of the microbes, it can also affect the overall quality of the final compost product. Think about it, would you want fertilizer that's really dry? No! Would you want fertilizer with low nutrient quality? No! Ash and lime can also take away some the nutrients in the compost that would make it good as a fertilizer. Thus, use of these methods must be balanced with the need to ensure a final product of good quality, which requires trial and error, since every situation is different. The quality of the final fertilizer will affect its growth and acceptability by the local community, discussed more below.

Also, most EcoSan operations worldwide, of which there are many, have been in small contexts: on the order of small villages, not cities or even large villages. Assuring the quality of the process and final product when operations are scaled up is a challenge that has not yet been encountered in the EcoSan community, but one that will have to be addressed in the near future.

Finally, there are obvious stigmas surrounding the re-use of our waste for agriculture or other processes that eventually produce crops, etc. that we consume. To many, this seems unclean, wrong, or otherwise unsafe. If done correctly, EcoSan can be effective and safe, but important conversations must take place between the community and those promoting EcoSan to make sure that everyone's on the same page. This is another challenge to the scaling up of operations discussed above as well.

What's the takeaway? 
For now, EcoSan provides an effective way to recycle some of the limited nutrients, like nitrogen and phosphorus, that would otherwise be wasted in a landfill. It does have its limitations, which at this point include the quality of the compost as a fertilizer, its ability to be used on a large scale, and the general acceptability of the whole process. Through careful development and cooperation, EcoSan can grow into a successful operation on a local scale. Whether it grows to succeed on a larger scale remains to be seen.


David Berendes is a first-year PhD student in the Environmental Health Sciences Department at Emory University's Rollins School of Public Health. His research interests include sanitation and environmental pathogen transmission.

No Soup for You?!?

Once again BPA is in the news. Or should I say, in the soup?

BPA, or bisphenol A, is an industrial chemical used to make plastics and resins that seems to have been linked to everything from developmental and reproductive effects to obesity, cardiovascular disease and diabetes.  

And over the last few years, headlines have proclaimed BPA to be found in -and on- everything from plastic water bottles, to canned foods, to receipts and even money!

This latest follows a study published in last week's edition of the Journal of the American Medical Association, a team of researchers at the Harvard School of Public Health conducted a study of 75 participants that compared people who were given canned vegetable soup for lunch for 5 straight days  with people who consumed prepared vegetable soup -made without any canned ingredients- for 5 straight days

And what did they find?

That within a few hours after eating, those participants who had eaten canned soup had levels of BPA in their urine that were approximately 12x greater than the participants who had been eating the prepared vegetable soup! Although it's important to note that even though the study utilized Progresso brand soup, this is an industry-wide practice, so these sorts of results would be expected from other companies with canned soup products.

Scary, right?

Well, maybe not...it's important to keep in mind that these levels were still in what our government considers a safe range. But there is still a lot of public concern about potential public health effects of bisphenol A, but not a lot of solid answers. This is why reports of exposures to potential health hazards should always include at least a reference to information on health effects, or potential health effects. And ideally, the same for a method to reduce exposure!

As this type of report leaves me wondering....we know we're exposed to BPA...but what are the realistic health effects? 

Not very clear! But BPA is currently being investigated, by private and public institutions, including the US Food and Drug Administration and the National Toxicology Program at the National Institutes of Health, especially as regards possible effects of BPA on the brain, behavior, and sexual development in infants and young children. Dr. Burcher, Associate Director of the National Toxicology Program, has explained that BPA is considered to be of some concern  because "scientists that have looked at this information recognize that there is something really going on here, but it's not exactly clear".  For more information about the NTP conclusions, see the NIEHS page on the topic.

So, while the jury--or in this case, the science---is out, what can/should you do?

Minimize your exposure to BPA by minimizing your exposure to the products we know are likely to be contaminated! That means in addition to ditching the BPA-containing plastic water bottles, you should think about trying to reduce overall consumption of canned goods. At the least, try to minimize consumption of canned food that is acidic, like canned tomatoes, or salty, because BPA is more likely to leach from the epoxy-resin linings of these cans right into these types of food!

Take the opportunity to try out a few recipes yourself....you never know, you might even enjoy cooking!

And on the bright side, we know that this approach can work...last March the journal Environmental Health Perspectives published the results of a small Silent Spring-sponsored study in which twenty participants from five families eliminated canned and packaged foods for only three days, but were able to reduce their levels of BPA exposure by approximately 60%!

Mary M. is doctoral student at Emory University's Rollins School of Public Health. If you need a little inspiration in the kitchen, she might just have a recipe for you!

A Social Experiment

You are where you live. A new study shows that low-income individuals who move to high-income neighborhoods have less obesity and better blood sugar control than individuals who stay in low-income neighborhoods. Past studies have shown that neighborhoods impact their residents’ health, but this is the first to show that changing from one kind of neighborhood to another can positively benefit an individual, even if most other things about that person’s life stay the same.

In the October 20^th issue of the New England Journal of Medicine, Dr. Jens Ludwig, et al. published a paper on the health effects observed in the Department of Housing and Urban Development (HUD)’s Moving to Opportunity (MTO) demonstration project. MTO was a case-control study designed to measure the role that neighborhoods play in health. Participants in MTO were randomly selected Section 8 housing recipients in high-poverty neighborhoods in five major US cities. They were divided into three groups. The first group was given vouchers to allow them to move to a new neighborhood with a low level of poverty. The second group was given vouchers to allow them to move to a new neighborhood that was not necessarily different socioeconomically. The third group was not given vouchers. The health of individuals in all three groups was tracked over time.

Those participants who received vouchers to move to higher-income neighborhoods and chose to move were less likely to be obese and less likely to have uncontrolled diabetes than those who did not receive vouchers, even though the two groups were initially very similar. This is an important finding because it highlights the way that where one lives impacts one’s health and that moving can change that impact. Though the reductions in obesity and diabetes were small (around 2-3% overall), they were significant—few other interventions even come close. As Dr. Thomas W. McDade, a coauthor  of the study notes, “The magnitude of the effects of the experiment are striking, and are comparable in size to the effects on diabetes we see from targeted lifestyle interventions or from providing people with medication to prevent the onset of diabetes.”

However, it’s important to keep in mind that the study is, at its most fundamental, a social experiment. HUD does not have the resources or ability to incentivize all Section 8 housing recipients in high-poverty neighborhoods to move to more healthful areas. Even if they did, there are not enough housing options for that to be a feasible option. So, if it cannot be widely implemented, why does this matter, other than to satisfy the curiosity of public health researchers and urban developers? This study opens the door to asking what it is that makes low-poverty neighborhoods that much healthier. Past studies have shown that some features of many low-poverty neighborhoods, like lower crime rates, better access to fresh fruits and vegetables, and parks may have positive effects on wellbeing. MTO is a chance to reexamine these factors and see if there are others, like transportation options and school quality, which might also play a role. Determining which of these are effective can help guide city planners in improving existing high-poverty neighborhoods to make them healthier, even if they do not become wealthier.

This study also makes a case for adding more mixed-income housing in low-poverty neighborhoods. While it is important to not abandon high-poverty neighborhoods (hence the role of city planners and ongoing urban improvement), incorporating more Section 8 housing into low-poverty areas may serve as a stop-gap. Ethically, financially, and logistically, it is not possible to clear out all high-poverty neighborhoods and relocate former residents to low-poverty neighborhoods in the name of public health, but providing individuals with options to live in more mixed-income areas may show a benefit.

Sources:

Anyaso, Hilary Hurd. “From High to Lower Poverty.” Northwestern University News Center. Accessed Nov. 7, 2011 http://www.northwestern.edu/newscenter/stories/2011/10/poverty-study-mcdade.html

Ludwig, Jens, et al. Neighborhoods, Obesity, and Diabetes—A Randomized Social Experiment. New England Journal of Medicine 2011; 365: 1509-1519. October 20, 2011.
Wheeler, Helen Rippier. "Berkeley's Housing Authority Administers Section 8, Public Housing." Accessed Nov. 7, 2011 http://www.berkeleydailyplanet.com/photos/05-14-04/5%253A14%2520rectangle.jpg

Author:

Kira Newman is a second year MD/PhD student beginning the PhD portion of her education in epidemiology.  Her research interests focus on the nexus between environment and health.  Kira brings a broad background to translational research including primary research in historical epidemiology and practical epidemiology experiences at CDC and state levels.  Biking, climbing, and scavenging free food are her passions.