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Cle ansing nuclear fallout from the body

Nov. 13, 2006
Courtesy Pacific Northwest National Laboratory
and World Science staff

A U.S. gov­ern­ment re­search­er is stu­dy­ing ways to clea nse the body of nu­cle­ar fall­out, us­ing a chem­i­cal from crab and prawn shells.

A por­ce­lain crab, Pe­t­ro­lis­thes cinc­ti­pes. (Cred­it: Jo­n­a­thon Still­man)

As con­cerns over nu­cle­ar pro­lif­er­a­tion grow, so do wor­ries that an at­tack­er could set off a suit­case-sized bomb in a ma­jor cit­y.

That would spread ra­di­o­ac­t­ive ma­te­ri­al over a wide ar­ea, ex­pos­ing vic­tims to var­i­ous ra­di­o­ac­t­ive el­e­ments. Some of these can find their way in­to the body, where they keep pro­duc­ing ra­di­a­tion for years and of­ten cause can­cer.

There are no ef­fec­tive meth­ods known to purge the bo­dy of this ma­te­ri­al, sci­en­tists say, al­though they have made some head­way on treat­ments that tem­per its ef­fects.

Ta­tia­na Lev­it­skaia of the Pa­cif­ic North­west Na­tion­al La­b­o­ra­to­ry in Rich­land, Wash., is re­search­ing a new ap­proach. It’s based on a wide­ly avail­a­ble ma­te­ri­al, chi­to­san, found in the shells.

The substance, which is non­tox­ic, is a chela­tor, or com­pound that at­taches it­self to me­tal­lic atoms. Co­in­ci­dent­al­ly, the word “che­la­tor” it­self has crab­by ori­gins; it’s de­rived from the Greek chele, or claw, be­cause the chem­i­cal at­tach­ment mech­an­ism is rem­i­nis­cent of a lob­s­ter- or crab-like grasp­ing ac­tion.

Chi­tosan can also be chem­i­cally mod­i­fied to en­hance its abil­i­ty to clasp ra­di­o­ac­t­ive atoms, Lev­it­s­ka­ia said. Many of the ra­di­o­ac­t­ive el­e­ments in nu­cle­ar fall­out are met­als, in­clud­ing plu­to­ni­um, ura­ni­um, stron­ti­um and co­balt.

Chi­tosan is also eas­i­ly ex­pelled from the bod­y, and sci­en­tists spec­u­late that af­ter link­ing to the ra­di­o­ac­t­ive sub­stances it could take them with it. That would pre­vent their build­up in the bones, liv­er, kid­neys and oth­er or­gans. 

For now, Lev­it­skaia is in­ves­ti­gat­ing the ef­fec­tiveness of chi­to­san and si­m­i­lar sub­stances in re­mov­ing co­balt from lab­o­ra­to­ry rats. She re­ported on her re­search at the na­tion­al meet­ing of the Amer­i­can Chem­i­cal So­ci­e­ty in mid-September, say­ing re­sults are ex­pected this fall.

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Scientists have begun studying ways to cle anse the body of nuclear fallout using a chemical from crab and prawn shells. As concerns over nuclear proliferation grow, so do worries that an attacker could set off a suitcase-sized bomb in a major city. That would spread radioactive material over a wide area, exposing victims to various radioactive elements. Some of these can find their way into the body, where they keep producing radiation for years and often cause cancer. There are no effective methods known to cl eanse the body of this material, scientists say, although they have made some headway on treatments that mitigate its effects. Tatiana Levitskaia, a researcher with the Pacific Northwest National Laboratory in Richland, Wash., is investigating a new approach. It’s based on a readily available material, chitosan, found in the crustaceans’ shells. Chitosan, which is nontoxic, is a chelator, or chemical that attaches itself to metallic atoms. Coincidentally, the word “chelator” itself has crabby origins; it’s derived from the Greek chele, or claw, because the attachment mechanism is reminiscent of a lobster-like grasping action. Some chitosan materials can be chemically modified to enhance their ability to clasp radioactive atoms, Levitskaia said. Many of the radioactive elements in nuclear fallout are metals, including plutonium, uranium, strontium and cobalt. Chitosan is easily purged from the body, and scientists speculate that after linking to the radioactive substances it could take them with it and prevent their buildup in the bones, liver, kidneys and other organs. Levitskaia is investigating the effectiveness of chitosan and related substances in removing cobalt from laboratory rats. She reported on her research at the national meeting of the American Chemical Society in mid-September, saying results are expected this fall.