Fracking Up Baby

This study has not been peer-reviewed. It was presented at a meeting of the American Economic Association on January 4. It has also not been posted anywhere, to my knowledge. I am relying on an article written by reporter Mark Whitehouse for Bloomberg News. (I will update this post if I get further relevant information.) The credibility of the study seems to be quite high. The researchers are Janet Currie of Princeton, Katherine Meckel of Columbia, and John Deutsch and Michael Greenstone of MIT, who have previously published studies of the health effects of pollution. The study was funded by the Environmental Protection Agency and the MacArthur Foundation.

The authors used Pennsylvania birth records to compare the health of newborn infants living within 2.5 kilometers (slightly over 1.5 miles) of natural gas fracking sites to a control group of infants living elsewhere in Pennsylvania. Public records allowed them to pinpoint the exact latitudes and longitudes of the gas wells and the mothers' homes. Those babies whose mothers lived near a fracking site had a 9% probability of low birth weight (less than 5.5 pounds), compared to 5.6% in the control group.

Photo by AP/Keith Srakocic

Low birth weight is an important predictor of infant health and survival, and is associated later in life with inhibited growth, lower educational attainment, and chronic diseases. There is growing evidence that one of its causes is exposure to environmental toxins. The fracking group also had a 5% chance of a low Apgar score, double the control group. The Apgar score is given by the doctor, who evaluates the child's heart rate, breathing, muscle tone, reflexes and skin coloring at the time of birth. A low score indicates problems in one or more of these areas.

This is not the first study to find that fracking is associated with infant health problems. Faith Hill, a Cornell undergraduate, found that Pennsylvania children born near fracking sites had lower birth weights and lower Apgar scores compared to a control group of infants born near permitted sites prior to any drilling. However, this study could have been confounded by migration away from the site after drilling began and a reduction in property values in the vicinity. The net result is that people living near drilling sites may have lower socioeconomic status or other characteristics that could explain their children's poorer health.

The Currie study attempts to deal with this problem two ways. It corrects statistically for geographical differences in maternal health. More importantly, it looks at a subsample of mothers who gave birth both before and after drilling began. These mothers serve as their own control group, which eliminates most alternative explanations. Of course, the mothers were older after the onset of fracking, but lower birth weight is typically associated with younger maternal age.

How does fracking result in poor infant health? The authors claim that water pollution is probably not the cause, since there were no differences between mothers who used public water systems and those who obtained their water from private wells, which are more likely to be contaminated by fracking. This leaves air pollution as the most likely possibility. Pollution may be due to leakage of gases from around the well or from open frackwater waste pools, which are allowed in Pennsylvania. 

Whitehouse ends his article with the following odd bit of false balance:

The study doesn't necessarily tell us whether or not fracking is worth doing. There may be offsetting health benefits related to the added jobs fracking creates, to lower energy prices or to the reduced use of coal or other fuels as more natural gas becomes available.

Seriously? Are children to be sacrificed for lower energy prices? The comment ignores the possibility that Pennsylvania could impose stricter regulations to reduce air and water pollution near fracking sites, if its state government were not a wholly-owned subsidiary of the natural gas industry. 

Fracking is exempt from the Clean Air Act, the Clean Water Act and other federal anti-pollution regulations. So far, government has largely ignored the precautionary principle when it comes to fracking. The burden of proof has been placed on opponents of fracking to demonstrate health problems after the damage is done. If the drilling companies want to claim health benefits of fracking, I hope they will show us their data.

As of this morning, none of Pennsylvania's major newspapers have reported the study.

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 Some rights reserved by United Nations Photo

New international research has shown that particulate air pollution (or soot) is a significant cause of low birth weight in infants. The study is actually a meta-analysis of 14 studies done in nine countries, with a total sample of over 3 million births. A meta-analysis is an analysis of analyses, or a way of statistically combining the results of several studies to arrive at an overall estimate of the significance of an effect. The fact that the studies were done by different researchers, at different sites, using slightly different research methods is generally seen as increasing our confidence in the outcome.

Pollution at the study sites varied from 10 to 70 micrograms per cubic meter of air. The effect was small but consistent. Two ways of summarizing the results are:

• For every 10 microgram increase in pollution, average birth weight declines by 8.9 grams, or roughly one-third of an ounce.
• For every 10 microgram increase, the probability that an infant will be of low birth weight—less than 5 pounds, eight ounces—increases by 3%.

The effect was highly significant when controlling for the socioeconomic status of the mother and other confounding variables.

The two major sources of particulate pollution are industrial plants, especially power plants, and vehicle emissions. Exposure has been shown to be associated with health problems such as asthma, heart disease, stroke and diabetes. It's not clear why particulate pollution reduces birth weight, but one possibility is that it, and the diseases with which it is associated, place stress on the mother's body, which affects fetal growth. Low birth weight is a risk factor for infant mortality, and for heart, lung and behavior problems in later life.

A recent article in The Lancet attempted to quantify the major causes of premature death in the world. Air pollution was #7, contributing to 3.2 million deaths per year. (In case you're wondering, high blood pressure is #1, smoking #2, and alcohol consumption #3.) As David Pettit of the Natural Resources Defense Council notes:

Fortunately there are many actions that can be taken to address outdoor air pollution. The technology is readily available at a fraction of the investment cost compared to the health costs that the public bears.

Obviously, the availability of clean air technology is of little consequence if the corporations responsible for most of the pollution control a corrupt political system.

As if to show how obsolete our political system is, last August, the U. S. Court of Appeals struck down an Environmental Protection Agency rule intended to reduce emissions crossing state borders, partially on grounds that the rule was a violation of states' rights.