Hennie Eksteen, an expert on worms, has researched many astonishing features of these humble creatures including this one: "They can encapsulate toxic heavy metals before excreting them, which leaves the metals isolated in a hard shell. This is what happened after Chernobyl nuclear accident, and why the local environment looks so good now." (1)
In addition, worms from the Chernobyl may have changed their sexual behavior to increase their chances of survival. This is one of the first pieces of direct evidence on how wildlife is affected by radioactive pollution. Researchers suggest that the worms switched from asexual to sexual reproduction as they are capable of doing, and this was an attempt to protect themselves from the radiation. (2)
Another example of worms and toxic environments is Foundry Cove which is on the Hudson River across from West Point. It has an impressive manufacturing history. During the Revolutionary War, a forge at the cove produced chains that were stretched across the Hudson to slow down British warships. Ammunition was produced in Foundry Cove during the Civil War, and the manufacture of batteries began about 60 years ago. Beginning around 1953 industry in the area dumped more than 100 tons of nickel-cadmium waste into the cove and nearby river. (3) Arsenic, lead and other toxins were also dumped into the river. (4)
This dumping was halted in the late 1970s due to the excellent efforts of local citizens.
Jeffrey Levinton found that as much as 25% of the cove's bottom sediment consisted of cadmium, which is highly toxic. Yet, many bottom dwelling invertebrates were present in numbers no fewer than in unpolluted areas at other sites. In an effort to learn why, Levinton investigated the cadmium tolerance of the most common invertebrate in the cove, a relative of the earthworm with the difficult to remember and pronounce name Limnodrilus hoffmeisteri. Whereas local cove worms thrived and reproduced, Limnodrilus from a nearby cove showed clear signs of distress or died when placed in Foundry Cove. Offspring of Foundry Cove worms raised in clean muds were also tolerant of cadmium, leading to the conclusion that genes were largely responsible for the tolerance. This degree of metal tolerance could have evolved in just 2 to 4 generations, or a couple of years. This was verified by exposing worms from an unpolluted site to cadmium laden sediment and breeding the survivors. By the third generation the descendants had 2/3 of the cadmium tolerance found in Foundry Cove worms. (3)
Levinton states that this capacity for rapid adaptation in the face of novel environmental challenge was startling, since no population of worms in nature have ever faced conditions like the one humankind created in Foundry cove. Furthermore, although some species inhabiting nearby waterways are missing from Foundry Cove, most adapted to the unusual condition. Just 100 years downstream is an Audubon Society sanctuary for migrating birds which has prospered.
References
Ivo Vegter, Extreme Environment, (Cape Town, South Africa, Zebra Press, 2012), 128
"Only in Ukraine," onlyukraine,blogspot.com, September 4, 2006
Jeffrey S. Levinton, "The big bang of animal evolution," Scientific American, 267, 84, November 1982
Gregg Easterbrook, A Moment on Earth, (New York, Viking, 1995), 59
Jack Dini is author of Challenging Environmental Mythology. He has also written for American Council on Science and Health, Environment & Climate News, and Hawaii Reporter.
