Internal contaminants

UHV is necessary but not sufficient to ensure an uncontaminated surface. Certainly, the surface will not be contaminated by atoms arriving from the vacuum space, but such contamination as it had before the vacuum was formed has to be removed by bombardment with argon ions. This damages the surface structurally, and that has to be healed by in situ heat treatment. That, however, allows dissolved impurities to diffuse to the surface and cause contamination from below. This problem has to be dealt with by many cycles of bombardment and annealing, until the internal contaminants are exhausted. This is a convincing example of Murphy s Law in action one of the many corollaries of the Law is that new systems generate new problems . 

Injection—The injection of hazardous materials into the body sounds, at first, like a bad joke. Who in his right mind would inject themselves—exp>ecially when it is not required by a doctor However, it can occur by stepping on or bumping against a sheup object while working at an incident site. It will happen before you even realize it has occurred and the reality of possible being internally contaminated sinks in. The best precaution for this eventuality is to have on protective clothing and observe safe work habits. 

Proper selection and sizing of ventilation systems require knowledge of emissions from internal contaminant and heat sources and an understanding of the mechanisms and characteristics of air and contaminant movement. 

Plutonium has a much shorter half-life than uranium (24.000 years for Pu-239 6,500 years for Pu-240). Plutonium is most toxic if it is inhaled. The radioactive decay that plutonium undergoes (alpha decay) is of little external consequence, since the alpha particles are blocked by human skin and travel only a few inches. If inhaled, however, the soft tissue of the lungs will suffer an internal dose of radiation. Particles may also enter the blood stream and irradiate other parts of the body. The safest way to handle plutonium is in its plutonium dioxide (PuOj) form because PuOj is virtually insoluble inside the human body, gi eatly reducing the risk of internal contamination. 

Breuer F, Clemente GF, Strambi E, et al. 1980. A case of internal contamination with plutonium oxide. 

Cohen N, Sasso TL, Wrenn ME. 1979. Metabolism of americium-241 in man An unusual case of internal contamination of a child and his father. Science 206 64-66. 

Patients who show no evidence of external contamination but may have received internal contamination via a wound or inhalation or ingestion of contaminants do not need to be decontaminated prior to treatment. However, blood, vomit, urine, and feces from these patients may be contaminated and should be controlled as such. 

External decontamination procedures are designed to minimize internal contamination of patients and the individuals providing care. Radionuclides on the intact skin surface rarely produce a high enough absorbed dose to be hazardous to patients or to medical staff. However, this is not the case for chemical hazards. Prior to implementing decontamination procedures, a patient should be moved to an upwind position outside of the area of contamination. 

UV light has been combined with hydrogen peroxide to develop a produce decontamination that can be used to inactivate pathogens on the surface and internalized contamination (Hadjok et al., 2008 Xie et al.,... 

To demonstrate this capabihty, Wagh et al. group worked with Bechtel Jacobs Co., the contractor at Oak Ridge, and conducted a feasibility study. The smdy comprised macroencapsulation of internally contaminated pipe sections [23]. 

Swab body orifices. WHEN EXTERNAL CONTAMINATION IS SUSPECTED Assess potential tor internal contamination. Use separate saline- or water-moistened swabs to wipe inside ot each nostril, mouth, and each ear. ... 

Urine—24-hour specimen times 4 days. Feces—24-hr specimen times 4 days. WHEN INTERNAL CONTAMINATION IS SUSPECTED Excreta may contain excreted radionuclides Use 24-hour urine collection container, if there was an uptake. ... 

Low-level contamination with thermal, chemical, radiation burns, and/or trauma. Internal contamination possible. Consult with specialist if possible. 

Extensive contamination and associated wounds. Internal contamination probable. Consult with specialist it possible. 

For the supeiwision of the persons working in radiochemical laboratories, pocket dosimeters (generally ionization dosimeters) and film dosimeters are used. The lower detection limits of these dosimeters vary between about 1 and 40 mR. Furthermore, hand foot monitors are installed near the exit of the laboratories, by which external contamination can be detected. In the case of suspected internal contamination, the person is checked by means of a whole-body counter which allows detection of y-ray emitters with high sensitivity. The presence of natural contributes essentially to... 

One hundred and twenty-nine had external and internal contamination... 

Internal contamination Though inhalation, ingestion or transdermal absorption, radioactive material is deposited into body tissues... 

After stabilization and external decontamination, patients require assessment for radiation injury based on dose, specific isotope involved and the presence of internal contamination. By performing individual biodosimetry, physicians can predict the subsequent clinical severity, survivability and treatment required, as well as triage patients with subclinical or no exposure (2). The three most useful items for estimating exposure doses in a mass casualty situation are ... 

The FDA has approved the oral administration of Prussian Blue (ferric hexacy-anoferrate) to treat internal contamination with cesium and thallium (16). Prussian Blue works by increasing fecal excretion of these elements. Patients require treatment only if the exposure dose of Cs exceeds the annual limit (200 uCi from inhalation or 100 uCi from ingestion) (5). Clinicians should consult with a health physicist to determine whether exposure has exceeded the annual limit. Treatment for exposures between one and ten times the annual limit is controversial. However, exposures exceeding ten times the limit usually indicate the need for treatment. Once treatment has reduced the level of internal contamination below the annual limit, Prussian Blue treatment can stop. However, the clinician can use his or her discretion to discontinue treatment if residual levels remain above the annual limit after prolonged treatment (5). 

The FDA recommends 3 g Prussian Blue three times daily for adolescents and adults and 1 g three times daily for children aged 2-12 years for a minimum of 30 days. Clinicians can adjust the dosage and length of treatment based on the level of internal contamination. The chief Prussian Blue side effect is constipation, and clinicians should use Prussian Blue carefully for patients with impaired gastrointestinal motility (5). 

United States Food and Drug Administration, Center for Drug Evaluation and Research. Guidance for Industry on Prussian Blue for Treatment of Internal Contamination with Thallium or Radioactive Cesium, Avarlabrtity. Federal Register/Vol. 68, No. 23/Tuesday, February 4, 2003/Notices, http //www.fda.gov/OHRMS/DOCKETS/98fr/03-2597.pdf, last accessed 1-01-06... 

Internal contaminants should be controlled by dilution and flushing of contaminants in the room, or by displacement airflow (See Figs 6 and 7 for examples of methods for the flushing of airborne contaminants.)... 

Miiller J, Klener V, Tuscany R, et al. 1966. Study of internal contamination with strontium-90 and radium-226 in man in relation to clinical findings. Health Phys 12 993-1006. 

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