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Indirect military occupational lead exposure to children at home: a case report.

Historically, lead has been an important commodity for industry, including metal alloys, cosmetics, medicinal preparations, and paint pigments. Concomitantly, lead poisoning has been well described since early Greek history (2nd century BC), and, more recently (19th century), adverse health outcomes were well defined in workers and children. (1) By the 20th century, more indepth studies revealed the cumulative toxic effects of lead exposure, especially among the vulnerable population of children. (1,2) Today in the United States, there are an estimated 4 million households with potential childhood lead exposures, and nearly half a million US children (ages 1-5 years) are known to have blood lead levels (BLLs) above 5 [micro]g/dL, the recommended public health action level of the Centers for Disease Control and Prevention (CDC). (3,4) Although BLLs have demonstrated an overall dramatic decline in the past few decades, lead exposures among high risk populations (low-income, African American, urban, and rural mining communities or developing countries) still exist. (5)

Interestingly, lead toxicity can affect nearly every body system. Because subclinical presentations are common among lead exposed patients, this public health risk frequently goes unrecognized. Throughout the world, children remain a persistent at-risk population due to prevalent hand to mouth behavior, close proximity to lead exposures, and physiologic higher gastrointestinal absorption per unit body weight and increased respiratory rates. (5) Regardless of the route of entry, the toxic effects of lead exposures remain uniform. (1) Specifically, lead binds to erythrocytes which can then transfer to multiple organs (brain, liver, kidneys, spleen, muscles, lungs, and heart), and the majority of the lead can absorb onto bones and teeth after several weeks. (1) Further, exposures to lead at low levels (BLL less than 10 [micro]g/dL) in childhood has also been shown to contribute to deficits in central nervous system functioning and cognition. (6,7) Children may exhibit "pica," a unique manifestation of elevated BLL which involve abnormal eating habits with soil or paint chips. (5)

Within a child's environment, main lead exposures derive from diet, contaminated soil, paint in homes built before 1978, water pumped through leaded pipes, imported clay pots, certain consumer products such as candies, make-up, jewelry, certain imported home remedies, electronics, and toys. (1,3,5) Indirect exposures from adult recreational activities such as take-home lead dust from firing ranges have also been documented. (8,9) More importantly, certain parental occupations (ship yards, manufacturers, and handlers in lead alloys including batteries and ammunition) can also pose considerable risk to the child. (10) Therefore, occupational lead exposures can indirectly expose the employees" families and children under the age of 6 years by take-home lead dust on clothes, boots, hands, and face. (3,11-13)

In 1991, the CDC responded to this growing public health concern by issuing new guidelines. (1,3) This included an emphasis on the child's environmental history, parent education, and follow-up for children with BLLs of 10 [micro]g/dL or greater. (1) More recently, the American Academy of Pediatrics emphasized lead screening history in a 2005 guidance statement, and the CDC recommended initial and follow-up screening (within 1 to 3 months) of pregnant and lactating women, neonates, and infants of women with BLLs of 5 [micro]g/dL or greater. (4) In May 2012, the Advisory Committee on Childhood Lead Poisoning Prevention recommended the use of a reference range for an elevated BLL based on the growing body of literature that levels less than 10 [micro]g/dL do indeed adversely affect children. (1,3-5,11,14) Thus, the current value (5 [micro]g/dL) identifies children with elevated BLLs. (3,15) Understanding the complex toxic effects of lead exposures among children underscores the importance of primary prevention and vigilant surveillance and screening.

CASE STUDY

An 18-month-old female was seen in the pediatric clinic for complaints of "pica." She was known to eat unusual items such as cat food, wood chips from the stair railings, chalk, and paint off the walls. The birth history revealed a normal term delivery via emergency C-section with breech presentation without complications or hospitalizations. The mother of the child denied any past surgical history, but the child's past medical history was significant for chronic constipation treated with diet and medications. Also, her mother expressed concerns of child's development delays in speech, but she denies any neurologic deficits; skin manifestations; bone, teeth, or nail deformities. Family history was unremarkable and there are no siblings or other family members in the living environment whether foreign or domestic. There was no history of travel or visitors from outside the country.

Since September, the family lived on the military installation with well-developed housing (post-1980s) and no history of lead in paint, soil, or water systems. The child was formula fed with the introduction to whole milk at 9 months old, and currently she is solely on whole milk with a normal diet of solid foods. Her mother denied any foreign-made toys, ceramics, or products that would contain lead. The mother consistently was a "stay at home" mom. Her recreational activities included crochet and bow hunting, but she denied any participation of the latter since they moved to the current duty station. At the time, The child's father was a Soldier in the US Army; his occupation (Field Artillery) was in small arms munitions and Howitzers, but mostly he worked in the motor pool. The mother stated that he worked with lead products and had coveralls at the workplace; however, he did not change his boots from work to home. Although he washed his hands upon entering the home, he denied taking any showers prior. According to the mother, his boots and duty uniform was typically located in a common place, the laundry room, and were not segregated. The child has had full access of the contaminated clothing, and was known to play with the work boots constantly. The father's recreational activities included hunting with a rifle, but he has denied any shooting range activities since arrival at this post. Both father and mother drove separate cars, and the child only traveled with the mother in her vehicle. The mother denied any history of cross contamination between the car seats.

A review of the medical history showed the 12-month visit had normal results on the Ages and Stages Questionnaire (ASQ) and lead screening. Although the subsequent 15-month visit still revealed a negative lead screen, the mother reported significant chronic constipation with decreased ASQ scores in fine motor skills. All growth parameters were appropriate for age. A follow-up visit with the primary care provider revealed the diagnosis of "pica," although there was still a negative lead screening. Laboratory results included a normal hematocrit/hemoglobin (12.5/36.8) for her age group. However, serum lead levels were elevated (6 [micro]g/dL). Public health officials were notified and an evaluation of the work and home environment was conducted.

The installation Industrial Hygiene (IH) Department conducted a home visit using Lead Check swabs (3M, St Paul, MN). Initial qualitative findings revealed positive lead contamination only on the father's uniform and boots, with negative results in other high risk areas within the home. The IH team then performed a health hazard survey of the father's workplace (Field Artillery motor pool) including lead surface sampling. The workers in the motor pool provided routine wheeled vehicle and armaments maintenance. Although lead exposure can occur both via ingestion and inhalation, airborne levels of lead in the motor pool were anticipated to be very low risk, whereas the presence of residual lead on Field Artillery equipment from firing activities could lead to exposure through eating, drinking, and tobacco use. One important concern was take-home lead dust on uniforms and boots which could contaminate privately owned vehicles and home environments. All quantitative samples were collected using Ghost Wipes with a 100 [cm.sup.2] template. The samples were then sent for analysis to the US Army Public Health Command by ASTM Method E1613. * The samples were reanalyzed by the laboratory using Environmental Protection Agency (EPA) Method 200.8 ([dagger]) to better quantify lead at the lower levels. To note, the IH Group at Brookhaven National Laboratory has established industrial guidelines for lead dust based on standards developed by the Department of Housing and Urban Development and the EPA. Based on these guidelines, dust wipe samples standards included 40 [micro]g/[ft.sup.2] for nonlead operational areas. Final sampling above the 40 [micro]g/[ft.sup.2] cutoff revealed positive for the Soldier's front of uniform pants, top and bottom of boots, and front of the mechanic coveralls, shown in the Table.

Primary exposures to lead were associated with routing maintenance activities. The lead sampling indicated the presence of lead in quantities sufficient to warrant precautionary procedures to minimize risk of lead exposure to Soldiers and family members. These procedures included enforcing the use of dedicated coveralls in the workplace and changing areas, not wearing uniform boots into the home environment with segregation of any potentially contaminated clothing items transported in a plastic bag, prohibited eating, drinking, or using tobacco products in the maintenance section, and integrated washing areas for hands, face, and shower activities before interacting with the home environment.

COMMENT

Indirect occupational exposure to lead in the home environment is a military-relevant topic with enormous public health risks. In the mid-1900s, certain US policies were enacted to protect children from environmental and industrial lead exposures which led to the sharp reduction in children's BlL (1976 thru 1989). (2,16) Thus, legislative actions have proven the effectiveness of public health interventions in light of emerging research that elevated BLLs in children can cause serious adverse outcomes. (17-19) Although the follow-up lead levels, particularly for this child, revealed a definitive decline below threshold limits of lead levels after workplace interventions, improvements in early detection, surveillance, and prevention are still needed to protect any long term effects to a child's development in the military home. Future studies in population risks in the environmental and occupational setting among the military are warranted.

ACKNOWLEDGMENT: The material in this article has been reviewed by the Walter Reed Army Institute of Research. There is no objection to its presentation and/or publication.

REFERENCES

(1.) Meyer PA, Brown MJ, Falk H. Global approach to reducing lead exposure and poisoning. Mutat Res. 2008; 659:166-175.

(2.) Levin R, Brown MJ, Kashtock ME, et al. Lead exposures in US children, 2008: implications for prevention. Environ Health Perspect. 2008; 116:1285-1293.

(3.) Centers for Disease Control and Prevention. CDC

Response to Advisory Committee on Childhood Lead Poisoning Prevention Recommendations in "Low Level Lead Exposure Harms Children: A Renewed Call for Primary Prevention". June 7, 2012. Available at: http://www.cdc.gov/nceh/lead/AC CLPP/CDC_Response_Lead_Exposure_Recs.pdf. Accessed March 17, 2017.

(4.) Centers for Disease Control and Prevention. Low Level Lead Exposure Harms Children: A Renewed Call for Primary Prevention: Report of the Advisory Committee on Childhood Lead Poisoning Prevention of the Centers for Disease Control and Prevention. January 4, 2012. Available: at https://www. cdc.gov/nceh/lead/acclpp/final_document_030712. pdf. Accessed March 12, 2017.

(5.) Ahamed M, Siddiqui MK. Environmental lead toxicity and nutritional factors. Clin Nutr. 2007; 26(4):400-408.

(6.) Needleman HL, Schell A, Bellinger D, Leviton A, Allred EN. The long-term effects of exposure to low doses of lead in childhood. An 11-year followup report. N Engl J Med. 1990; 322:83-88.

(7.) Surkan PJ, Zhang A, Trachtenberg F, Daniel DB, McKinlay S, Bellinger DC. Neuropsychological function in children with blood lead levels <10 microg/dL. Neurotoxicology. 2007; 28(6):1170-1177.

(8.) Valway SE, Martyny JW, Miller JR, Cook M, Mangione EJ. Lead absorption in indoor firing range users. Am J Public Health. 1989; 79:1029-1032.

(9.) Bonanno J, Robson MG, Buckley B, Modica M. Lead exposure at a covered outdoor firing range. Bull Environ Contam Toxicol. 2002; 68:315-323.

(10.) Dolcourt JL, Hamrick HJ, O"Tuama LA, Wooten J, Barker EL Jr. Increased lead burden in children of battery workers: asymptomatic exposure resulting from contaminated work clothing. Pediatrics. 1978; 62:563-566.

(11.) Lanphear BP, Hornung R, Ho M, Howard CR, Eberly S, Knauf K. Environmental lead exposure during early childhood. JPediatr. 2002; 140(1):40-47.

(12.) Lanphear BP, Roghmann KJ. Pathways of lead exposure in urban children. Environ Res. 1997; 74:67-73.

(13.) Charney E, Sayre J, Coulter M. Increased lead absorption in inner-city children: where does the lead come from?. Pediatrics. 1980; 65:226-231.

(14.) Gilbert SG, Weiss B. A rationale for lowering the blood lead action level from 10 to 2 microg/dL. Neurotoxicology. 2006; 27(5):693-701.

(15.) Canfield RL, Henderson CR, Cory-Slechta DA, Cox C, Jusko TA, Lanphear BP. Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter. N Engl J Med. 2003; 348(16):1517-1526.

(16.) Pirkle JL, Kaufmann RB, Brody DJ, Hickman T, Gunter E, Paschal DC. Exposure of the US population to lead, 1991-1994. Environ Health Perspect. 1998; 106:745-750.

(17.) Bellinger DC, Needleman HL. Intellectual Im pairment and Blood Lead Levels. N Engl J Med. 2003; 349(5):500-502. Correspondence. Available at: http://www.nejm.org/doi/full/10.1056/ NEJM200307313490515#t=article. Accessed April 19, 2017.

(18.) Bellinger DC, Stiles KM, Needleman HL. Lowlevel lead exposure, intelligence and academic achievement: a long-term follow-up study. Pediatrics. 1992; 90:855-861.

(19.) Dietrich KN, Ris MD, Succop PA, Berger OG, Bornschein RL. Early exposure to lead and juvenile delinquency. Neurotoxicol Teratol. 2001; 23:511-518.

LTC(P) Paul O. Kwon, MC, USA

AUTHOR

LTC(P) Kwon is the Director, Preventive Medicine Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland.

* https://www.astm.org/Standards/E1613.htm

([dagger]) https://www.epa.gov/sites/production/files/2015-08/docu ments/method_200-8_rev_5-4_1994.pdf
Results of analyses of the home and workplace sampling for
possible lead contamination.

Item                          Lead Concentration      Positive
                                  ([micro]g/       (>40 [micro]g/
                                 [ft.sup.2])        [ft.sup.2])

Front of uniform pants               69.7               Yes
Top and bottom of boots              82.7               Yes
Mechanic desk area                  < LOQ                No
Mechanic work table                 < LOQ                No
Top of mechanic uniform              23.2                No
Mechanic desk area                  < LOQ                No
Front of mechanic coveralls          45.5               Yes

LOQ indicates limit of quantitation.
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Author:Kwon, Paul O.
Publication:U.S. Army Medical Department Journal
Article Type:Clinical report
Date:Jan 1, 2017
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