Scientific Literacy and Sensationalist Journalism

This morning my friend Dan sent me a link to this AP News story: Sludge Tested As Lead Poisoning Fix.

The story begins: "BALTIMORE - Scientists using federal grants spread fertilizer made from human and industrial wastes on yards in poor, black neighborhoods to test whether it might protect children from lead poisoning in the soil. Families were assured the sludge was safe and were never told about any harmful ingredients."

Holy crap. This is good lead, well-written, and it suggests everything is still wrong with the world. The government is funding scientists to run experiments on the effects of toxic and human waste on poor black families? It's a horrible, horrible thing, if it's true, and both the US government and agribusiness have funded this sort of terrible experiment on minorities and on the poor in the past. It brings to mind all sorts of eugenics nightmares, and our country unfortunately has a rich tradition of doing much worse to the poor and to minorities. So on the surface it seems tragically plausible.

The story continues: "Nine low-income families in Baltimore row houses agreed to let researchers till the sewage sludge into their yards and plant new grass. In exchange, they were given food coupons as well as the free lawns as part of a study published in 2005 and funded by the Housing and Urban Development Department." It then goes on to explain that the high levels of phosphate in the sludge can bind to heavy metals, including lead, "allowing the combination to pass safely through a child's body if eaten", and that federal policy has been based on this idea for decades, despite a 1978 Environmental Protection Agency (EPA) memo that said the sludge " 'contains nutrients and organic matter which have considerable benefit for land and crops' despite the presence of 'low levels of toxic substances' ".

Wow. So the sludge itself, already toxic, contains additional toxins, and the EPA has known for years. Furthermore, a scientist at the National Academy of Science (who is a Johns Hopkins professor of public health) worries that the sludge is worse than that: it's human waste, so there's nasty microbes in it. And the EPA funded another study to test the sludge in another poor black neighborhood in East Saint Louis, IL, to see if the phosphates did bind to lead... this time in a vacant lot next to an elementary school. So, all in all, things look bad for this study. At this point I asked, "Why would the government fund this sort of study? Especially when I have such non-controversial paleo research in need of funding?"

At this point, the story started raising red flags with me. It quotes a local environmental advocate: "If you wanted to do something very questionable, you would do it in a neighborhood that's not going to be there in a few years", then launches into a description of the main researcher, Mark Farfel, also at the Johns Hopkins School of Public Health (remember? his critic above also was there. But so are three more of Farfel's co-authors. Red flag.). Apparently, he is also the recipient of several government-funded projects looking at the effects of lead in urban poor neighborhoods. The article seems to imply that his reign of lead and toxic waste terror extends further than this study, but to me it makes sense that if he studies the effects of lead poisoning, he would do it more than once, and in areas with high levels of lead. I dismissed this as the reporters not understanding the nature of scientific specialization. The story briefly mentions that the study passed the standards at Johns Hopkins for public health studies involving humans.

The story then takes an abrupt turn for the conspiratorial. The last part of the article starts by saying Farfel denied repeated requests for interviews (What does he have to hide???), then makes a point of stating that Farfel now works interviewing 9/11 victims. Are we supposed to assume he is now torturing 9/11 victims, poisoning them with human and toxic waste, like he did to the urban poor? The story next explains that some of his previous work has been controversial, that people associated with his previous research have sued for lead poisoning. Scientifically, this is a methodological red flag for me, but the article doesn't dwell on what happened to those people, only commenting on the resulting court case: "The Maryland Court of Appeals likened the study to Nazi medical research on concentration camp prisoners, the U.S. government's 40-year Tuskegee study that denied treatment for syphilis to black men in order to study the illness and Japan's use of 'plague bombs' in World War II to infect and study entire villages." So you are left with the impression that this racist, immoral asshole is exploiting American tax dollars to poison the poor. He's done it in the past, therefore he is doing it now.

So, is this a case of horrible people (Nazi-esque, even) taking advantage of government funding to perform experiments on poor minorities? Is this a return to eugenics? Or, is this a case of a story taking advantage of Americans' lack of scientific literacy to sell papers (or gun for a Pulitzer)? I decided to look into it. Fortunately, the research in this study was published [1] (though I couldn't track down a reference for the case that went to court), and even better, my university had access to the journal. So I read the article, and now I would like to call into question some of the 'facts' in the AP story:

#1. TOXIC HUMAN WASTE SLUDGE IS PUT ON LAWNS
As it turns out, it's not raw sewage at all. It's not a sludge. It's not even liquid. The product they used in this study is a compost fertilizer called Orgro, and you can buy it in bulk commercially, or at a garden store. One of its ingredients is treated human sewage, but it is composted with woodchips and sawdust first. According to the study, Orgro "is approved by U.S. EPA and the Maryland Department of the Environment (MDE) for unlimited use in lawns and gardens as a soil conditioner/fertilizer". This is important because to get that certification, you have to make sure it is safe to put on people's lawns. So the rules are: any fertilizer that uses any animal or human waste must be pasteurized to kill pathogens before it can be sold and used for residential purposes. This process is how we make milk safe to drink. While you probably wouldn't want to make an Orgro milkshake, I think it's safe to assume the bad microbes are pretty much nonexistant in Orgro. The article points out that there were already people in Baltimore using it to make their lawns look nicer before the study started. And this site claims that Orgro is "sold for use on golf courses, athletic surfaces and the lawn of the residence of the Vice President of the United States". So: safe enough for rich people.

#2. SLUDGE DOES NOT MAKE SOIL LEAD SAFER
Orgro is rich in phosphate and iron, and both (but especially phosphate) bind to lead (and zinc, another contaminant) in a way that makes it nonsoluble (so it won't dissolve when it rains) and bio-inaccessible (so organic things can't break it down with enzymes and then become poisoned). So it's marketed as a fertilizer that can make your contaminated soil grow plants again. And because of this, it also has been used as a treatment for toxic soils. In this study, they mixed the Orgro (which, again, is compost, not raw sewage) with the first ten or twelve inches of soil, then seeded it.

So where does this research come in? There are two problems the study is trying to address: there is a lot of lead in urban soils, and the soil is well-exposed because plants can't grow there (because there's too much lead and lead is toxic to plants). So when kids play on the soil, it's easy for kids to get at and be exposed to the lead in the soil. The kids undoubtedly already had lead levels before the start of the study. Now, the best way to clean up lead contaminated soils is to completely replace it with new clean soil, which brings us to the second problem: most cities can't afford to remove all the soil and bring new stuff in, and federal government regulations are written such that unless it is a Superfund site, they will not pay for soil replacement. The study cites long-term studies on the health risks of this stuff, and it has been used before in non-urban toxic places (in MO, ID, PA, and Poland, as well as several Superfund sites). They know what high doses do to small animals and adult humans. Orgro just had not been field tested in an urban setting before. The idea behind the study was that it could be a cheaper way (and thus, affordable to urban homeowners and cities) to treat soil for lead, and at the same time, get the soil covered up with grass so the kids had less direct access to it.

The study did not test whether stomach acids can break the bonds between phosphates and lead. That may be true, or it may not be. I don't know how long something that is bio-inaccessible can stay that way. But the study did find that the bio-accessible lead levels were reduced by 50-70% in one year, in the areas of highest concentration. We're not talking low levels of lead here, either; many of these lawns had lead levels 3-5 times higher than the EPA's maximum safe amount. If anyone in this study has elevated lead levels at the end of the study, I'd bet a lot of money that they had them before the start of the study. And it did show that Orgro can be used to grow grass where little grass grew before (the pics are pretty amazing). So the study succeeds in both counts: neutralization of lead and preventing access to lead in soils by covering it up with grass.

#3 SLUDGE ADDS TOXINS TO SOIL
This interested me a lot. What were the toxins that Orgro (again, not sludge) was putting into the soil, the toxins the landowners weren't informed of? We know from above that it's not microbes. Does the study address this at all? It turns out that it does. The toxins in question are... heavy metals. That's right, stuff like lead and zinc, which is present in all soils to some extent. And they know how much was in the Orgro, because they tested it. They needed to measure it as a control on the experiment; they needed to know how much they were adding to the system, because those were the exact things they were trying to neutralize in the soil. It turns out that the levels of heavy metals in the soil were very, very low; much lower than the EPA's safe amounts, and negligible when compared to what was already in the soil.


Now, I have no idea what motivates Mark Farfel to do his research. He could hate the poor. He could hate black people. He could take personal delight in seeing them sick and suffering. It does not come through in his writing. His research seems sound to me, and he seems to be motivated by helping people, not harming them. But I'm not an environmental scientist, nor an epidemiologist. And, furthermore, I'm not completely sure about the quality of the journal in which this study was published, "Science of the Total Environment" (impact factor: 2.359, read more about it here). But the article I read was peer-reviewed and pretty straightforward, and didn't raise any statistical or methodological red flags with me. If you have compelling arguments against the article, I'm open to hearing them. But in the meantime, I think we can chalk this up to journalistic sensationalism. Which kind of sucks for Mark Farfel, his co-authors, the study participants who now feel victimized (unnecessarily), and the government agencies who will now be pressured not to fund future research in this vein.

Reference:
1. Farfel MR. 2005. Biosolids compost amendment for reducing soil lead hazards: a pilot study of Orgro(R) amendment and grass seeding in urban yards. Science of the Total Environment 340: 81– 95.