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Going Nuclear: Z for Zacariah

Nuclear disasters have been fodder for science fiction since the 1950s—we wouldn’t have 1954’s ant invasion flick Them! or any number of Godzilla movies without the existence of atomic power. But more recently, a number of both fiction and documentary films are reengaging audiences with nuclear contamination scenarios. In addition to two documentaries traveling the festival circuit, The Russian Woodpecker and The Babushkas of Chernobyl, Craig Zobel’s new post-apocalyptic drama Z for Zachariah examines life in the wake of a nuclear disaster.

To better understand the effects of radiation on living populations, Sloan Science and Film spoke with Tim Mousseau, professor of Biological Sciences at the University of South Carolina, who, since 1999, has been exploring the consequences of the radioactive contaminants affecting birds, insects and people inhabiting the Chernobyl region of Ukraine, and more recently, in Fukushima, Japan.

Sloan Science and Film: What exactly is your area of research in terms of radiation?

Tim Mousseau: We got involved in it purely by accident. We are mostly evolutionary biologists and evolutionary ecologists. So we got started in Chernobyl because of our interest in adaptable evolutionary responses to this unique environmental stressor. There’s been lots of work done on the toxicological effects of radiation, from nuclear bombs or medical uses, but there’s been no ecological or evolutionary studies done. So that’s what motivated us. First, we started looking at adaptive responses. But then we quickly started uncovering all these negative consequences for individuals and populations that had really never been documented before.

The first thing we noticed is that a lot of the birds were lighter in color, or even had patches of white feathers mixed in with normal colored feathers. The big discovery is that we’re starting to see the same kinds of partial albinos in Fukushima now. We started to look at how long the birds lived, which was shorter in time, and we also looked at male fertility, and found out that upwards of 40% were effectively sterile. This wasn’t a complete surprise, because if you look at the medical literature, men undergoing radiation therapy for cancer are recommended to bank their sperm if they’re young enough, because of the known impact on fertility. What was surprising was to see it in the birds in the wild that were exposed at levels that were considerably less than what a cancer patient would be receiving. This ties into the tumors and cataracts and many other afflictions we’ve seen in the birds. Many species, but not all, are showing dramatic declines in numbers.

SSF: What about people?

TM: I have been collaborating with a hospital in Kiev that specializes in treating children from areas with high contamination. We have started several projects for evidence of genetic damage: damage to the genes that are transferred from one generation to the next, and chromosomal damage and patterns of damage to the whole genome. But we don’t have any results to share just yet.

SSF: Let’s talk about the post-nuclear environment, in general. Chernobyl seems like a fairly good real-life example. So it is habitable, in a way, yes?

TM: Both Chernobyl and Fukushima provide good examples of what could happen if there was so to be some major disaster. It’s not directly lethal. It doesn’t stop you in your tracks. It contributes to the rate of aging and it adds more mutations to your DNA, so you don’t live as long and you don’t perform as well; you’re more likely to pick up diseases; you’re more likely to pick up tumors. So life goes on. But it doesn’t go on as successfully.

SSF: What about the disbursement of radiation? In Z for Zachariah, there is this valley that is left untouched by the radiation, whereas all of the surroundings are fully contaminated. Is this plausible?

TM: My initial response is that this is silly. But in truth, in Chernobyl, for instance, we find large pockets of pristine areas nested among areas of high contamination, simply because the way that the radioactivity is disbursed. Radioactivity comes from particles of elements that are a result of radioactive decay, which means they are carried up in the wind. In Chernobyl, there was radioactive fire burning, so the particles of radioactive elements were carried up in that plume of fire and injected into the atmosphere at different lengths depending on the temperature of the fire. And that injection height determined how fast the wind was blowing, so they ended up being carried long distances and they only ended up dropping to the ground when there was rainfall. There is a tendency for the highest level of radiation to be within 100 miles from the power plant. But lighter volatile lower-density materials such as iodine and xenon and krypton went up very high and were dispersed much further. So the type of nuclear disaster and the interaction with the atmospheric processes determines where and when the radioactive particles drop back to the earth.

SSF: What about crops? I imagine all the food is contaminated. What would be your prognosis for the characters in Z?

TM: It all depends on how radioactive it is. The premise of the movie is that they’re in this valley that escapes all of the radioactive disposition—except for the water. But if it’s in the water, it’s going to be in the valley eventually. You have to irrigate the plants with something. One response is there’s no escaping it. The scenario sounds like the mountaintops were contaminated and so the water is picking it up and bringing it down to the valley. So eventually, the valley is going to grow more and more contaminated. This is analogous to what’s happening in areas in Japan; they’re trying to clean areas and are literally vacuuming up the soil in an effort to reduce the ambient radiation levels. The same is true in the valley in the film. What one might expect is that slowly over generations the radioactivity is going to increase and the genetic load associated with exposure is going to increase and reduce the average fitness. In a lot of natural populations, there is a balance between births and deaths, but if you add an extra stressor, and reduce the average fitness, it will eventually send that population into a death spiral, an extinction spiral—the birth rate can’t keep up the with death rate. That would be my expectation. That would eventually not be able to escape it.