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February 2006
The Problem with Poop

The Satya Interview with Amy R. Sapkota


Hen in a manure pit. Photo courtesy of Wegmans Cruelty

Industrial animal production has not only consolidated sentient individuals into intensely concentrated areas, but also their waste—about 1.4 billion tons generated annually. With the rise of Concentrated Animal Feeding Operations or CAFOs, animal waste has become a big environmental and health problem.

At the Center for a Livable Future at Johns Hopkins University, Dr. Amy R. Sapkota is researching how different agricultural practices affect the environment and public health. As research director of the Industrial Animal Production Project, she is looking at the impacts of animal waste from CAFOs, particularly hog farms. The project was inspired by animal activist Henry Spira and collaborates with the factory farm project at GRACE (Global Resource Action Center for the Environment), which helps communities confront CAFOs. The goal of this project is to address the impact of industrial animal production and apply these research findings to the development of good public policy initiatives.

While currently in France doing research on transgenic plants, Dr. Amy Sapkotaspoke with Sangamithra Iyer about her research.

How did you get involved in studying Concentrated Animal Feeding Operations or CAFOs?
There are many different reasons why I’ve pursued this research. There hasn’t been a lot of rigorous research conducted that has looked at the specific environmental and public health effects associated with CAFOs. And part of this is due to the fact that it is hard to gain access to these facilities, as well as the communities around them. Producers don’t want researchers negatively impacting their livelihood if the research findings are not in favor of their production methods, and sometimes communities are also reluctant to get involved with research activities.

I wanted to come from a rigorous scientific approach, studying what we need to understand in terms of air emissions and waste emissions from these facilities, and what specific ways they are affecting the environment and human health. I also wanted to generate hard data that demonstrates what is really going on with these facilities, instead of being clouded by public perceptions and misconceptions. I think we can only move forward with better policies regarding the regulation of CAFOs if we have good science to back them up.

Can you talk about the impact of animal waste from factory farms on the environment in general?
First, animal waste is not a bad thing. In sustainable agriculture it is something that is used for fertilizer for crop production. From my perspective the problem lies in the concentration of these facilities. If they were more strategically located, further away from each other and also smaller in size, we wouldn’t have such a concentration of waste in just one area. For example, we are not really producing that many more hogs than we were in the 1950s, but they are all produced in very concentrated regions in the U.S. versus being scattered over the roughly three million hog farms that existed in the 50s.

With CAFOs, there is just so much waste produced that there really isn’t a sustainable way to manage it. Also, because of some of the production methods used in CAFOs, the waste can contain things that are harmful like heavy metals such as arsenic. Through our research, we are also finding high levels of antibiotic resistant bacteria in this waste as well. We believe this is largely due to the non-therapeutic use of antibiotics in these facilities.

What are some of the differences or similarities among pig and poultry CAFOs?
Poultry are a lot smaller than hogs, so in your average poultry house, you can have 30,000 to 40,000 birds, versus a typical swine house that can have 2,500 to 3,000 hogs.
With respect to waste, poultry waste is usually a lot drier. Poultry houses are cleaned out once every one or two years—not too often. The poultry waste is then stored in what is called a windrow, which is essentially a very large pile of waste that is generally stored in some sort of large shed. That waste is then either land applied, incinerated, or pelletized for future use as a fertilizer product.

Pig waste is more of a liquid product and is either stored in lagoons or pits beneath barns. It is usually siphoned off with some sort of truck or piping system and sprayed on fields either onsite or offsite. In the lagoons and pits, solid material settles to the bottom. In theory there is anaerobic decomposition of the solids, but if a large amount is being dumped into these lagoons, the question is, is there enough time for the decomposition to take place?

I was wondering if you could comment on chicken waste and its impact on the Chesapeake Bay?
One of the problems is the physical location of a lot of the poultry operations. Many are in ecologically sensitive areas, such as the Delmarva Peninsula, which is essentially the eastern shore of the Chesapeake Bay that is shared by Delaware, Maryland and Virginia. The whole Delmarva Peninsula is not only one of the largest poultry producing areas in the country but also [part of] Chesapeake Bay watershed. Therefore, much of the poultry waste that is produced and land applied in this sensitive ecological watershed can ultimately end up in the Bay.

What do you find to be the biggest human health risks of factory farming?
Based on the research I’ve conducted, the problem of antibiotic resistant bacteria developing in these operations is one of the key issues. The resistant bacteria can end up on food products, as well as in the air and water surrounding these facilities.

I also believe that the use of arsenic, a known human carcinogen, in both poultry and swine production is a significant issue. Producers are using an arsenical compound known as Roxarsone as a feed supplement for our poultry and swine. Arsenic is not only a food safety issue, but also an environmental issue, as it could potentially end up in our surface waters and groundwater. Because it is a heavy metal, you can’t get rid of it. For example, even if you incinerated the waste, you are just going to be releasing the arsenic into the air.

What are the other risks that CAFOs pose in terms of air pollution?
Many different compounds are emitted from CAFOs. For example, in swine air emissions, there are over 160 compounds that have been characterized. Those include particulate matter such as dust, particles of skin, and particles of fecal matter. There are also gases, including methane, hydrogen sulfide, and ammonia. Volatile organic compounds that haven’t been fully characterized are emitted as well.

It is generally the odor associated with these plumes and emissions that is causing people to challenge CAFOs in their areas. It is very difficult to live with that sort of odor on a daily basis.

It seems that hog farms in general are more notorious.
You do see more attention to swine farms in terms of community health effects. However, I don’t know whether the reason is that there has been very little research conducted in communities that are located around poultry facilities, or whether the people who live around hog facilities have a more powerful or stronger voice, or are more organized. I am not exactly sure why the hog facilities are receiving more attention. It also might be because of location. Perhaps the hog farms are located in more densely populated areas versus the poultry facilities.

I know the factory farm project at GRACE works with communities affected by CAFOs. Have you been directly involved with communities confronting CAFOs?
I can give you an example of one activity that I was personally involved in. This occurred in the Peach Bottom Township in Pennsylvania where there was a proposal for the construction of a swine CAFO in an area where there were over 3,000 homes. The community sought the advice of a number of different people. We provided testimony regarding the public health and environmental effects associated with such facilities. Fortunately for the time being, Pennsylvania has not approved the construction of this particular swine CAFO.

I understand that your project inspired by Henry Spira hopes to be a “do” tank rather than a “think” tank. What is it you hope to do?
We use our research findings to try to move forward good public policies. A good example of this is that the director of the Center for a Livable Future, Robert Lawrence, recently testified in front of a congressional house subcommittee. There is a current bill in Congress that is proposing to remove animal waste from the regulatory purview of the superfund law, which is the Comprehensive Environmental Response Compensation and Liability Act. In response to this proposal, Dr. Lawrence testified on the public health and environmental health effects associated with CAFOs and his testimony included many of our research findings coming out of the Johns Hopkins Bloomberg School of Public Health.

We are not only doing research and publishing it in peer-reviewed journals, but we are trying to speak about our findings in settings that can actually have an impact on federal policies.

Can you talk a bit more on some of the public policy initiatives?
Currently, the Bush administration is whittling away at some of our strongest environmental laws, including the Clean Air Act and the Clean Water Act. In general, we work to prevent these laws from being eroded even more. These laws are very important in terms of controlling both airborne emissions and waste emissions from CAFOs. The CAA covers airborne emissions, including particulate matter and hydrogen sulfide, and the CWA has a program called the National Pollution Discharge Elimination System, which covers waste related discharges coming from CAFOs. We are trying to use our research findings to maintain the effectiveness of these types of laws.

How have you found getting access to information about CAFOs?
It is difficult to gain access to these facilities to study them in the first place. However, there are some producers who do want to be good environmental stewards and don’t want their farming practices to be negatively impacting the environment and public health. You have to seek out these like-minded people and work with them.

In terms of data, it is very difficult to gain access to the types and amounts of antibiotics being used in CAFOs. In the U.S., this important data is just not collected. To study antibiotic resistant bacteria coming from these facilities, it is nice to know as a starting point what antibiotics are actually being used. Unfortunately, even some of the producers don’t know precisely what antibiotics are in the feed, because the feed is often delivered by the larger company that they contract with and is siphoned into their silos. Sometimes a producer is willing to collaborate with you to do research, but they still might not have all of the answers about what exactly is in the feed.

In contrast to the situation in the U.S., some of the European countries, like Denmark, have excellent systems where they collect data on how much and what types of antibiotics are being used in the feed.

You’ve mentioned the potential erosion of some of our strongest environmental laws. Can you comment on policy initiatives regarding animal welfare?
Unfortunately, that is also a big difference between the U.S. and Europe. Europeans in general, and European scientists and policy makers, are more aware and interested in animal welfare. They have more regulations on the books than the U.S. does.

In discussing the impact of antibiotic resistant bacteria, are there links being made between the conditions in which the individuals are kept in these facilities and the need for antibiotics?
The reason they are feeding non-therapeutic levels of antibiotics is primarily to promote growth. It is an economic reason—getting the animals to market as efficiently and quickly as possible. There is a question as to whether animals can be raised under confined conditions in the U.S. without the use of any antibiotics. We know that this is being done in Europe where the usage of non-therapeutic levels of antibiotics has been replaced by better management and hygienic practices.

Researching factory farms, you probably have some interesting stories. Is there anything in particular you feel compelled to share?
It’s hard to make overall statements because each of the facilities we’ve visited has had their own quirks. However, the odor of swine is probably one of the most intense odors I’ve ever smelled. As an example of this, the odor truly sticks to our notebooks and our equipment for years after sampling in the facilities. It is a very sticky, intense smell that really stays with you even after your research is finished.

Has working on these issues affected your own personal dietary choices?
Well, I’ve been a vegetarian my whole life almost. I grew up in a family where my mother was vegetarian. So, no.

To learn more about the Center for Livable Future visit To find out more about factory farms and what to do if a CAFO comes to your town go to



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