- Refugee and internationally adopted children, especially from resource-poor countries, may have elevated lead levels in their body when they arrive in Canada.
- Immigrant and refugee children may also be at risk of lead exposure after arriving in Canada.
- Sources of lead include environmental contamination, cooking utensils, cosmetics and food items.
- Lead exposure may cause no symptoms, produce vague, chronic symptoms or present acutely.
- A high index of suspicion is needed for lead exposure in newly arrived children. They should be screened as soon as possible after arrival and, ideally, rescreened 3 to 6 months later when risk factors or anemia are present.
Lead in newcomer children
Lead exposure is a concern in young newcomers to Canada and especially in refugee and internationally adopted children. They remain at risk for elevated levels of lead and lead toxicity despite declining rates in North American-born children.
As the symptoms of lead toxicity can present in a variety of ways, a high index of suspicion is required. Primary prevention of lead exposure in children is imperative because the harmful effects on cognition, as well as on cardiovascular, immunological and endocrine function, may be irreversible.1
Also, no lower blood lead level (BLL) threshold is considered ‘safe’,2 and the U.S. Centers for Disease Control and Prevention recently lowered their threshold for action from ≥10 μg/dL (≥0.48 μmol/L) to ≥5 μg/dL (0.24 μmol/L). The lower threshold is based on evidence indicating that a BLL <10 μg/dL has harmful effects on cognitive, cardiovascular, immunological and endocrine function. A BLL ≥5 μg/dL “should trigger lead education, environmental investigations, and additional medical monitoring”.1
Patterns, sources and rates of lead poisoning vary among and within countries. The burden is greatest in low-income countries: 90% of children with elevated lead levels live in low-income regions.3 One review identified 57 worldwide ‘hot spots’ for environmental lead poisoning in children:4 see Figure 1. However because of limited data, the number of hotspots may be much higher. The number and location of high lead levels is also changing over time.
|Figure 1. Map of children’s average BLL, estimated in studies published from 2000 to 2010|
Note: Map numbers correspond to references listed in the original paper. Median BLL (μg/dL).
Source: Clune AL, Falk H, Riederer AM. Mapping global environmental lead poisoning in children. J Health Pollution 2011;1(2):14-23.
Sources of lead vary depending on the region of the world but may include leaded gas, used batteries, leaded paint, cookware or cosmetics.4-11 Refugees are at increased risk when refugee camps are located on or close to contaminated sites.12 Useful information on sources of lead is provided online by the New York State Department of Health.
While lead levels in North American-born children have been steadily declining in recent years,1,13 refugee children may arrive in Canada with higher than normal lead levels in their body. Data on lead exposure in children new to Canada are limited; however, U.S. data indicate that lead exposure rates among refugee children are high.14,15 For example, the prevalence of elevated BLL among refugee children <6 years of age arriving in the U.S. (2002 - 2007) was found to be 8x the national rate.15 Awareness concerning lead toxicity risks postarrival increased following the death of a Sudanese child who ingested paint from an old house 5 months after reaching the U.S.16 Newcomers often settle in poorer neighbourhoods, with sources of environmental lead contamination nearby.14 In Canada, living in older housing can increase exposure to lead: lead plumbing may have been used until 1950 and lead-based paint until 1976.17
Risk factors and sources of exposure
Lead exposures can occur before and after migration:1,4-11
- Environmental exposures premigration: Children, especially from low-income countries, may be at risk of environmental exposure pre-migration from sources such as leaded paint, batteries, cosmetics and cooking utensils that contain lead.
- Environmental exposures postmigration: Newcomer families may settle near industrial areas or live in older housing, while continuing to use lead-contaminated products from their country of origin (e.g., traditional therapies or imported food or cosmetics).
A malnourished child may be at increased risk of lead absorption. Refugee children in particular are often malnourished. Their diet may have been low in lead-protective nutrients such as iron and calcium over a long period, increasing intestinal lead absorption.
Common sources of lead exposure in children include:1,4-11,18
Food and cosmetics:
- Utensils, ceramic or metal dishes or pots
- Drinking water (from metal pipes, metal storage containers)
- Food, spices, candies (ingredients or packaging)
- Cosmetics (such as kohl (al-khal, kajal) and surma)
- Traditional medicines (notably from the Middle East, Southeast Asia, India, the Dominican Republic or Mexico).
Environments and industry:
- Emissions, especially from mining or smelting
- ‘Cottage’-based industries (e.g., breaking up batteries or metal ore)
- Leaded gasoline exhaust in high-traffic areas or in soil contaminated by leaded gasoline.
- Emissions from burning fossil fuels or waste.
A useful list of sources of lead is provided online by the New York State Department of Health.
Children experiencing lead toxicity are often asymptomatic19,20 and may therefore go undiagnosed. Signs and symptoms of lead exposure, when they do occur, can also be vague or chronic.20 Acute symptoms also occur, particularly with BLLs at >10 μg/dL.21 At BLLs >60 μg/dL, children may experience headaches, abdominal pain, anorexia, constipation, clumsiness, agitation and lethargy.22 Symptomatic lead toxicity should be treated as a medical emergency.23
|Impaired neurological development|
|Impaired growth and development|
Delayed sexual maturation
|Other||Increased dental caries|
Sources: Information drawn from references 20,24-29
Currently, there are no Canadian screening guidelines for lead exposure in young newcomers, but most experts believe that all refugee and internationally adopted children and youth should be screened postarrival. When there is a suspicion that a child has been exposed to lead postarrival or a child shows low hemoglobin at follow-up, lead level screenings at 3- and 6-month intervals should be considered.
Clinicians can help to prevent lead exposure in young newcomers to Canada by educating parents about potential harms and common sources of lead toxicity.23 Because sources may be culture-specific (e.g., traditional remedies, therapies or foods), it is important to explore possible risks in a culturally sensitive manner1 and address potential barriers to adopting medical advice, such as living in a substandard environment.
- CDC. Lead Poisoning Prevention in Newly Arrived Refugee Children: Tool Kit
- Health Canada. Lead and Human Health
Clinicians can direct parents to these online resources:
- CDC. Fact sheets on lead poisoning prevention information (English and Spanish) and Prevention tips.
- Health Canada. Reduce your exposure to lead.
- San Francisco Department of Public Health. Childhood Lead Prevention Program: Parent Information (English, Spanish and Chinese)
- CDC, Advisory Committee on Childhood Lead Poisoning Prevention. Low level lead exposure harms children: A renewed call for primary prevention. Atlanta, GA: CDC; January 4, 2012.
- Abelsohn AR, Sanborn M. Lead and children: Clinical management for family physicians. Can Fam Physician 2010;56(6):531-5.
- WHO. Childhood lead poisoning. Geneva, Switzerland: WHO, 2010.
- Clune AL, Falk H, Riederer AM. Mapping global environmental lead poisoning in children. J Health Pollution 2011;1(2):14-23.
- Kaul B, Sandhu RS, Depratt C, et al. Follow-up screening of lead-poisoned children near an auto battery recycling plant, Haina, Dominican Republic. Environ Health Perspect 1999;107(11):917-20.
- Ling S, Chow C, Chan A, et al. Lead poisoning in new immigrant children from the mainland of China. Chin Med J (Engl) 2002;115(1):17-20.
- López-Carrillo L, Torres-Sánchez L, Garrido F, et al. Prevalence and determinants of lead intoxication in Mexican children of low socioeconomic status. Environ Health Perspect 1996;104(11):1208-11.
- Rahbar MH, White F, Agboatwalla M, et al. Factors associated with elevated blood lead concentrations in children in Karachi, Pakistan. Bull World Health Organ 2002;80(10):769-75.
- Schwartz J, Levin R. The risk of lead toxicity in homes with lead paint hazard. Environ Res 1991;54(1):1-7.
- Stroh E, Lundh T, Oudin A, et al. Geographical patterns in blood lead in relation to industrial emissions and traffic in Swedish children, 1978-2007. BMC Public Health 2009;9:225.
- Suplido ML, Ong CN. Lead exposure among small-scale battery recyclers, automobile radiator mechanics, and their children in Manila, the Philippines. Environ Res 2000;82(3):231-8.
- Brown MJ, McWeeney G, Kim R, et al. Lead poisoning among internally displaced Roma, Ashkali and Egyptian children in the United Nations-Administered Province of Kosovo. Eur J Public Health 2010;20(3):288-92.
- Statistics Canada, April 2013. Health fact sheet: Blood lead concentrations in Canadians, 2009 to 2011. Catalogue no. 82‑625‑X.
- Geltman PL, Brown MJ, Cochran J. Lead poisoning among refugee children resettled in Massachusetts, 1995 to 1999. Pediatrics 2001;108(1):158-62.
- Proue M, Jones-Webb R, Oberg C. Blood lead screening among newly arrived refugees in Minnesota. Minn Med 2010;93(6):42-6.
- CDC. Fatal pediatric lead poisoning–New Hampshire, 2000. MMWR Morb Mortal Wkly Rep 2001;50(22):457-9.
- Health Canada. Lead and human health.
- CDC. International adoption and prevention of lead poisoning. February 2013.
- CDC. Medically oriented fact sheet. Lead poisoning prevention and treatment recommendations for refugee children. Refugee tool kit. Atlanta, GA: CDC, 2009.
- Warniment C, Tsang K, Galazka SS. Lead poisoning in children. Am Fam Physician 2010;81(6):751-7.
- CDC. Lead screening during the domestic medical examination for newly arrived refugees. Atlanta, GA: CDC, April 16, 2012.
- Canfield RL, Henderson CR Jr, Cory-Slechta DA, et al. Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter. N Engl J Med 2003;348(16):1517-26.
- 22. American Academy of Pediatrics (AAP) Committee on Environmental Health. Lead exposure in children: Prevention, detection, and management. Pediatrics 2005;116(4):1036-46.
- Gemmel A, Tavares M, Alperin S, et al. Blood lead level and dental caries in school-age children. Environ Health Perspect 2002;110(10):A625-30.
- Needleman HL, Riess JA, Tobin MJ, et al. Bone lead levels and delinquent behavior. JAMA 1996;275(5):363-9.
- Shukla R, Dietrich KN, Bornschein RL, et al. Lead exposure and growth in the early preschool child: A follow-up report from the Cincinnati Lead Study. Pediatrics 1991;88(5):886-92.
- Sood A, Midha V, Sood N. Pain in abdomen—do not forget lead poisoning. Indian J Gastroenterol 2002;21(6):225-6.
- Williams PL, Sergeyev O, Lee MM, et al. Blood lead levels and delayed onset of puberty in a longitudinal study of Russian boys. Pediatrics 2010;125(5):e1088-96.
- Wu T, Buck GM, Mendola P. Blood lead levels and sexual maturation in U.S. girls: The Third National Health and Nutrition Examination Survey, 1988-1994. Environ Health Perspect 2003;111(5):737-41.
- CDC. Managing elevated blood lead levels among young children: Recommendations from the Advisory Committee on Childhood Lead Poisoning Prevention. Atlanta, GA: CDC, March 2002.
- Anna Banerji, MD
Last updated: April, 2018