CURRENT STATUS:
Since 2003, the Army personnel's potential exposure of sodium dichromate at QA WTP has continued to receive media and Congressional attention. In November 2008 the Defense Health Board (DHB) reviewed the original assessment in September 2003 and concurred with the SMART-PM conclusions.
While there was potential for immediate health symptoms during the time of exposure to sodium dichromate in the summer of 2003, DCPH-A does not consider current or long-term health problems to be attributed to sodium dichromate.
What is Sodium Dichromate?
Sodium dichromate is typically in the form of a reddish/yellowish flake or powder. Sodium dichromate contains chromium (Cr VI), otherwise known as hexavalent chromium. Although some forms of chromium are essential for health, Cr VI can cause adverse health effects in certain doses. Cr VI does not occur naturally in the environment and is produced by industrial processes for several different uses such as chrome plating, wood preserving, manufacture of dyes and pigments, and, as in this case, an anti-corrosive for water pipes.
What are the Health Effects from Exposures to Chromium?
Health effects depend on:
- the type of chromium (e.g., Chromium III (Cr III) versus Cr VI)
- the route of exposure (e.g., ingesting versus breathing)
- the amount (levels) and duration of exposure
While Cr III is an essential nutrient that helps the body use sugar, protein, and fat, adequate amounts are usually obtained through a normal diet. If ingested in large amounts, both chromium III and VI can cause stomach upset and ulcers or kidney and liver damage, though Cr III is less toxic than Cr VI.
Cr VI can cause irritation to the nose, eyes, throat, and lungs. At high enough levels of exposure, symptoms may include watery eyes or nose, nosebleeds, sore throat, or cough. These symptoms resolve after the person is removed from the exposure. Repeated long-term inhalation exposure (weeks to months) to significant levels of Cr VI can cause chronic symptoms of inflammation and a classic clinical finding of nasal perforation. Repeated skin contact may cause skin ulcers (known as “chrome holes") and contact/irritant dermatitis. Some people may become sensitized to chromium and develop asthma or allergic dermatitis even at lower occupational exposure levels. Cr VI is known to cause cancer of the respiratory tract in occupational settings where long-term inhalation exposures occurred. See the
ATSDR Toxicological Fact Sheet
for additional information.
Were there any Chromium-Associated Health Effects Among Army Personnel Evaluated?
- Result
The medical team concluded that long-term health effects related to cancer or reproduction were
very unlikely from the Cr VI exposure at the QA WTP. They conveyed this information to Army personnel through fact sheets and town hall meetings. Those Army personnel with any exam findings or medical tests outside the normal range were advised to follow up with a healthcare provider. Army personnel with exposure concerns were told to express them on their post-deployment health evaluation, at which time appropriate referral and assessment would be conducted.
- Assessments Performed
Personnel providing security at the time of the (October 2003) health assessment were medically evaluated with a history, physical examination, and other testing described below. The assessment was modeled after the medical surveillance examination used for workers routinely exposed to chromium in their occupation.
- Duration of Exposure
The self-reported average duration of exposure at QA WTP was 18.5 (8-hour) days. This is a relatively short exposure time compared to the months and years of occupational exposure where long-term adverse health findings to Cr VI have been documented.
- Irritation-type Symptoms
Approximately one-fourth of the individuals evaluated complained of irritation-type symptoms related to the eyes, nose, throat, and lungs. Physical findings were also consistent with mild irritation and/or inflammation in those who had complained of symptoms. There were no nasal perforations or skin findings consistent with “chrome holes." All of the self-reported symptoms and physical findings were non-specific and could have also been caused by other exposures common to the desert environment and austere living conditions.
- Blood and Urine
Blood and urine tests only identified mild abnormalities most likely related to dehydration, protein and creatine supplement use, and pre-existing conditions. Abnormal blood and urine tests were just above the corresponding normal range. All chest x-rays were normal.
- Pulmonary Function
One-third of the pulmonary function tests had mild abnormalities. No baseline tests were available for comparison. The abnormalities were consistent with inadequate patient effort, making the test indeterminate; mild airway obstruction related to smoking or pre-existing asthma; and changes possibly related to exposure to ambient air in and around the base camps. All individuals with mild lung function abnormalities had no symptoms, except those with a history of mild asthma, who generally only reported symptoms with exertion.
- Whole Blood
Whole blood tests for chromium levels were performed as a marker of exposure. Whole blood testing identifies chromium in the blood as well as the chromium taken into red blood cells (RBCs). Sixty percent of Cr VI that does not enter RBCs is excreted within 8 hours. Cr VI stays in RBCs for the 120-day life span of the RBC and, thus, gives some indication of an individual's Cr VI exposure during the previous 3 to 4 months. The results for nearly all whole blood samples indicated that there was no difference in Cr levels, compared to reference population levels of people with no occupational Cr exposure. The blood test results indicated that there was not a significant systemic uptake of Cr VI. However, it is possible that low levels of exposure could have caused or contributed to the irritation symptoms and physical findings Army personnel reported at the time.
