Commentary Lead toxicity – a call to action Philip R. Fischer The Mayo Clinic, Rochester, USA
Invited commentary on ‘Blood lead levels in children attending a tertiary teaching hospital in Enugu, southeastern Nigeria’, Ugwuja et al. In 2010, international attention focused on the problem of lead toxicity in north-western Nigeria. An initial study involving more than 100 children found a mean blood lead level of 119 mg/dl (with levels .10 mg/ dl considered toxic).1 At that time, news media reported that over 100 children died of lead intoxication, and otherwise unexplained convulsions were increasingly seen. Gold mining operations, some informal, had left discarded lead in soil around at least seven villages. Soil contained .100,000 ppm lead with concentrations ,400 ppm routinely accepted as ‘safe.’1 Ninety per cent of children had blood lead levels .45 mg/dl, the level at which chelation treatment is advised. International assistance was mobilised. Thousands of children received chelation therapy. Village environments were decontaminated. Mortality in exposed children dropped from 43% in 2010 to 1% in 2011.2 A devastating tragedy subsided. Meanwhile, lead toxicity continues to plague Nigeria in important although less dramatic ways. As demonstrated by Ugwuja and colleagues in this issue of Paediatrics and International Child Health,3 approximately one-third of children (at least those presenting for routine medical care at a tertiary centre) in an area of south-eastern Nigeria have high blood lead levels, although not at the highly toxic levels noted in the 2010 mining-related outbreak. This is similar to findings in a series of studies in central Nigeria several years ago which showed that about one-third of children had lead levels .10 mg/dl and linking high lead levels to several factors including the use of lead-based eye cosmetics, proximity to informal recycling of vehicle batteries, and young age.4–6 A study in Egypt found lead toxicity to be common, with 26% of children (combining rural and urban children) having a blood lead level of .10 mg/ dl.7 Correspondence to: P R Fischer, Division of General Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA. Email: [email protected]
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Extremely high lead levels are linked to seizures and death, as seen in some of the mining-related affected children in north-west Nigeria.8 In Alexandria, Egypt, measurably lower intelligence quotient (IQ) scores were found to correlate with higher blood lead levels (in school children where 20% of students had levels .20 ug/dl).9 In Chennai, India, anxiety, social problems, and attention-deficit disorders have been linked to higher lead levels.10 Even at lower levels not requiring aggressive medical management, lead exposure is associated with significant negative outcomes in children. Most lead exposure is via the oral route. In young children, this can result from hand-to-mouth contamination when hands touch topically applied facial cosmetics11 or contaminated soil.4–6 In older children who tend to put their hands in their mouths less frequently, high lead levels suggest the possibility of contamination of food (such as plants that have absorbed lead in the soil) or beverages (perhaps from lead-containing pipes); nonetheless, others in Nigeria suggest that it is likely that older children too are exposed to lead from soil-contaminated hands.12 Informal lead acid battery recycling was also identified as the source of lead toxicity in a group of children who died in Dakar, Senegal.13 In China, ingestion of dust from a lead battery factory was linked to lead toxicity.14 For clinicians in Nigeria and other similar settings, Ugwuja et al.’s report is a reminder to test blood lead levels frequently and to provide chelation therapy as indicated. Unfortunately, however, in many areas of risk, lead testing and chelation are not readily available. More importantly, whether or not testing and chelation are clinically feasible, this report from southeastern Nigeria should stimulate public health interventions. A third of children in at least several regions of Africa are growing up at significant risk of compromised neurodevelopment owing to lead toxicity. Whether or not testing and treatment are available, appropriate engagement in decreasing environmental exposure to lead is essential. As professionals who are concerned for the next generation, we can advocate for the removal of leaded paint and leaded gasoline/petrol in areas in which they are still being used. Leaders of industrial plants should be encouraged to avoid allowing leaded waste to escape into the air or soil around inhabited areas. Ugwuja’s and colleagues’ report also serves as a ‘call to action’ for all who provide care to children. As
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paediatricians, we can advise families involved with informal mining or battery recycling to keep their work away from areas in which children will be in contact with soil, and we should advise families using eye cosmetics on children to use lead-free products. Also, people should be advised to wash their hands before handling food; the simple use of a sanitiser is probably insufficient to remove lead particles. It is a blemish on our profession and a scourge of society that we are allowing one-third of children in some parts of the world to grow up in environments in which lead toxicity is preventing them from reaching their full intellectual and social potential.
References 1 World Health Organization. Nigeria: mass lead poisoning from mining activities, Zamfara State, 2010. http://www.who.int/csr/ don/2010_07_07/en/ 2 World Health Organization. Nigeria: Mass Lead Poisoning from Mining Activities, Zamfara State – Update 1, 2011. http:// www.who.int/csr/don/2011_11_11/en/ 3 Ugwuja EI, Ogbu ISI, Umeaku EA, Otuu FC. Blood lead levels in children attending a tertiary teaching hospital in Enugu, south-eastern Nigeria. Paediatr Int Child Health. 2014;34:216– 19. 4 Pfitzner MA, Thacher TD, Pettifor JM, Zoakah AI, Lawson JO, Fischer PR. Prevalence of elevated blood lead in Nigerian children. Ambulatory Child Health. 2000;6:115– 23.
5 Wright NJ, Thacher TD, Pfitzner MA, Fischer PR, Pettifor JM. Causes of lead toxicity in a Nigerian city. Arch Dis Child. 2005;90:262–6. 6 Keating E, Fischer PR, Pettifor JM, Pfitzner MA, Isichei CO, Thacher TD. The effect of calcium supplementation on blood lead levels in Nigerian children. J Pediatr. 2011;159:845–50. 7 Abdel Rasoul GM, Al-Batanony MA, Mahrous OA, AboSalem ME, Gabr HM. Environmental lead exposure among primary school children in Shebin El-Kom District, Menoufiya Governorate, Egypt. Int J Occup Environ Med. 2012;3:186–94. 8 Lo YC, Dooyema CA, Neri A, Durant J, Jefferies T, Medina-Marino A, et al. Childhood lead poisoning associated with gold ore processing: a village-level investigation-Zamfara State, Nigeria, October–November 2010. Environ Health Perspect. 2012;120:1450–5. 9 Kamel NM, Ramadan AM, Kamel MI, Mostafa YA, Abo elNaga RM, Ali AM. Impact of lead exposure on health status and scholastic achievement of school pupils in Alexandria. J Egypt Public Health Assoc. 2003;78:1–28. 10 Roy A, Bellinger D, Hu H, Schwartz J, Ettinger AS, Wright RO, et al. Lead exposure and behavior among young children in Chennai, India. Environ Health Perspect. 2009;117:1607–11. 11 Sprinkle RV. Leaded eye cosmetics: a cultural cause of elevated lead levels in children. J Fam Pract. 1995;40:358–62. 12 Plumlee GS, Durant JT, Morman SA, Neri A, Wolf RE, Dooyema CA, et al. Linking geological and health sciences to assess childhood lead poisoning from artisanal gold mining in Nigeria. Environ Health Perspect. 2013;121:744–50. 13 Haefliger P, Mathieu-Nolf M, Lociciro S, Ndiaye C, Coly M, Diouf A, et al. Mass lead intoxication from informal used leadacid battery recycling in Dakar, Senegal. Environ Health Perspect. 2009;117:1535–40. 14 Chen L, Xu Z, Liu M, Huang Y, Fan R, Su Y, et al. Lead exposure assessment from study near a lead-acid battery factory in China. Sci Total Environ. 2012;429:191–8.
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