After the Three Mile Island nuclear reactor meltdown in Pennsylvania in 1979, regulators moved to overhaul safety requirements for nuclear power plants. This led to the temporary closure of some older nuclear power plants governed by the Tennessee Valley Authority (TVA) when they couldn’t meet the Nuclear Regulatory Commission’s (NRC) newly tightened standards.

Now, Carnegie Mellon assistant professor of economics and public policy Edson Severnini says those closures may have caused reduced birth weight in children in the area at the time, due to pollution exposure from the increased reliance on coal-burning power plants. The sudden removal of nuclear power, which doesn’t emit any greenhouse gases, led to a ramp-up in the amount of power being provided by nearby coal plants, Severnini wrote. That led to increases in particle pollution in areas adjacent to coal power plants, measured by the Environmental Protection Agency (EPA) in total suspended particulates (TSP).

At the same time, average birth weight for infants declined 134 grams.

Birth weight is a strong indicator of the health of a baby, and low birth weights can suggest a host of health issues in the future, including lower IQ and earlier mortality, particularly from cardiovascular complications. The author concedes that the exact biological mechanism that causes pollution to contribute to low birth weight is still under investigation, but other studies have found that there is a link between the two.

A unique story

Severnini looked at the closure of the Browns Ferry nuclear plant in Alabama in 1985 as well as the Sequoyah plant in Tennessee, which was closed from 1985 to 1988. The closure of the two plants corresponded to increased coal burning at nearby coal plants—in 1985, TVA noted in its annual report that coal plants had “extraordinary performance” due to the shut down of the nuclear plants.

The region also had hydroelectric power in its energy mix at the time, but additional hydro could not be added during the years studied due to lower-than-average rainfall. Thus, Severnini writes, “the substitution between nuclear and coal seems to be one to one, that is, each megawatt-hour not produced by nuclear power plants because of the shutdown appears to have been generated by coal-powered plants.”

Correspondingly, the level of TSP in the region increased, reversing downward TSP trends that had been brought on by the implementation of the 1970 Clean Air Act. (Severnini used a Freedom of Information Act request to access historical TSP readings that the Environmental Protection Agency had collected in the region throughout the ’80s). The author mapped TSP data on the county level and plotted the change in power generation at each of the coal-burning plants in the region.

He also gathered birth-weight data from the National Centre for Health Statistics (NCHS) and found that babies born in regions with the biggest increase in coal burning had lower birth weights than babies born in other nearby areas. Looking at data from 1983 to 1985, before the nuclear plant shut down, also showed that the largest change in birth weight occurred after the shutdown.

“That said, it appears that babies born in the first quarter after the shutdown were not affected at all,” Severnini writes. “From the second quarter onwards, however, infants born in areas with highly increased power generation and TSP induced by the shutdown were born with lower birth weight relative to the control group. Furthermore, the effect increased with exposure to additional pollution until leveling off. It was 97g for infants born in the second quarter after the shutdown, 146g in the third quarter, and of similar magnitude thereafter.”

Fresh air

The paper’s results are in line with other studies done on air pollution and birth weight. Notably, researchers found that in Beijing, babies whose mothers had their eighth month during the 2008 Olympics and Paralympics were on average 23 grams heavier than babies born the year before or after. This coincided with a national push to reduce air pollution in preparation for the global games, with the government taking cars off roads, closing factories, and “even [banning] outdoor spray-painting,” according to Science News.

Severnini writes that while nuclear disasters are definitely deleterious to human health, shutting down power plants should be weighed carefully against the cost of whatever is replacing that energy. After the Fukushima disaster in Japan, many countries moved to shut down nuclear facilities, but “the shutdown of nuclear plants in the US and abroad might not generate as much net benefit as the public perceives,” Severnini asserts.

Still, he admits that the tradeoffs seen in the 1980s aren’t the same as the tradeoffs most energy markets experience today. Natural gas plants are cleaner-burning, and renewable energy like wind and solar are more easily integrated into the grid. In the case of the planned shutdown of Indian Point in New York, for example, the governor’s office expects renewable energy to replace all or most of the 2GW plant’s capacity by 2021.

Nature Energy, 2017. DOI: 10.1038/nenergy.2017.51 (About DOIs).