(Tri Cities, Washington) During the Cold War, liquid waste containing radioactive salts was routinely discharged into the ground near the central part of the old Hanford Nuclear Facility, in the State Washington. The salts tended to attract various animals, including rabbits.
Prior to 1969, various animal interlopers had spread radioactivity through their droppings over a 13.7 square mile area surrounding the facility. The area has since been sealed off, but occasionally, animals are able to get through, and, as is believed in this case, sip some of the water left behind from a newly demolished structure.
Such structures are typically hosed down before demolishing to prevent radioactive dust from becoming airborne. But this spraying also leaves pools of water lying around in the exposed basements that are attractive to animals. And despite chain-link fencing, vegetation removal, and lacing the perimeter with fox urine, a thirsty critter or two can still get through.
Insects can also get through, of course, and can become a vector for spreading radioactive isotopes.
In 2003, waste water discharge near soil attracted mud dauber wasps, resulting in a slew of off-site, contaminated, mud hives that had to be contained and returned to the site for “disposal”. Not a fun job I would imagine.
What tipped off Health Dept. officials was the discovery by workers last week of contaminated rabbit droppings close to one of the site’s boundaries. Had the rabbit slipped out, and a dog caught the rabbit, the contamination (i.e., acquiring of cesium atoms undergoing radioactive decay) could have easily spread to humans — although how much danger this would present to public health is not clear. Still, when it comes to radioactivity (and the spotty history of the site), Washington Closure (the operation in charge of demolishing Hanford), and the Office of Radiation Protection, aren’t taking any chance.
(Added note: Hanford has had a rigorous anti-biological vector policy in place for many years, as noted in the comment below).
Rabbits in this area of the country are typically of the genus Sylvilagus (which has 13 member species), known as ‘cottontails’ (hares are a closely related animal but are generally non-burrowing). An unknown number of unidentified rabbits were trapped and one was found to be contaminated with radioactive cesium. It is not known how the contaminated animal was treated for its exposure. Since 2009, some 33 animals have been found on the site contaminated with radioactivity, according to a figure published in the Tri City Herald, and quoted in this Seattle Times article.
It is probable that any such contaminated animals are put down and buried.
What is Radioactive Decay? From wikipedia:
Simulation of many identical atoms undergoing radioactive decay, starting with either 4 atoms (left) or 400 (right). The number at the top indicates how many half-lives have elapsed. Note the law of large numbers: With more atoms, the overall decay is less random.
Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting ionizing particles or radiation (see animation above). The emission is spontaneous in that the nucleus decays without collision with another particle. This decay, or loss of energy, results in an atom of one type, called the parent radionuclide, transforming to an atom of a different type, named the daughter nuclide. For example: a carbon-14 atom (the “parent”) emits radiation and transforms to a nitrogen-14 atom (the “daughter”). This is a stochastic (non-deterministic) process on the atomic level, in that according to quantum mechanics it is impossible to predict when a given atom will decay. However, given a large number of similar atoms the decay rate, on average, is predictable.
Rabbit photo: Larry D. Moore, cc – by – sa 3.0, derivative (radiation symbol) work by M. Ricciardi
Wasp photo: psionicman ; cc – by 2.0
GIF animation: Sbyrnes321, public domain