11:00 〜 13:00
[MZZ51-P01] Lead Poisoning Among Residents of the Zambian Settlement of KABWE, Particularly Among Children
キーワード：Lead Poisoning, Kabwe, Zambia, blood Pb levels
Lead (Pb) is a non-degradable heavy metal with a high toxicity and negative health impacts. There is no known safe level of Pb exposure. Pb poisoning is still a public health concern, particularly in developing nations, due to its ubiquitous use. Exposure to Pb has been linked to a broad range of physiological, biochemical, and behavioral problems, including impaired cognitive performance in children, renal dysfunction, and cancer, to name a few. Moreover, it passes the placenta easily in pregnancy, leading to prenatal exposure. Although Pb poisoning is entirely preventable, it accounts for about 0.6% of the worldwide disease burden, with these countries bearing the highest burden. A recent global report by the Institute for Health Metrics and Evaluation (IHME) revealed blood Pb levels (BLLs) higher than the CDC reference level (5 µg/dL) in more than 800 million children, mainly in low- and middle-income countries. Because of their physiological and behavioral traits, such as habits of putting their hands, toys, and other objects into their mouths, children are prone to numerous adverse effects of Pb. This includes long-term cognitive impairment as well as functional abnormalities in the central nervous system. Pb can also easily pass the blood-brain barrier and damage the immature nervous system, which is where the most insidious effects of Pb exposure occur in children’s brains.
Kabwe town, Zambia, is ranked among one of the world’s most polluted places because of the Pb-Zn mine that operated for almost a century, from 1902 to 1994, without adequate pollution regulations addressing the potential dangers of Pb. As a result, although the mine is no longer active, the residue left behind and illegal activities around the mine have contaminated the soil and poisoned a generation of children. Thus, to address the contamination status of Pb pollution in Kabwe, blood samples were collected from a total of 1190 subjects. Blood samples were collected in 13 health centers after obtaining informed consent and completing a questionnaire collecting information on weight, height, age, sex, and socio-occupational category. Blood Pb levels (BLLs) were measured by the Lead Care® II analyzer.
The current study comprises 291 younger children (3 months–3 years old); 271 older children (4–9 years old); 412 mothers (average age of 39 years) and 216 fathers (average age of 46 years). The BLLs ranged from 1.65 to 162 mg/dL, with an overall average Pb level of 20.8 ± 21.4 μg/dL and a median level of 13.0 μg/dL (interquartile range: 1.65–40.3). There were different trends in BLLs among the population. Higher BLLs were found near the mining area, and the differences were significant.
Among the family, children had higher BLL than adults. There was a clear association between age and BLLs. The mean BLL was highest in the under 3 years-old group compared to the other age groups, consistent with the concept that hand-to-mouthing activities are expected to put children of that age at higher risk. In total, sixty-nine percent of the participants had confirmed BLLs of greater than 5mg/dL – a blood Pb reference value that raises ‘health concerns’ according to the CDC.
In summary, there is a potential for Pb poisoning in Kabwe, especially in townships close to the dump. This study revealed Pb exposure in the general population of Kabwe and supports the premise that the Kabwe Pb-Zn mine, closed over 25 years ago, is still the main source of Pb exposure and has poisoned the residents. It raised great concern about its health implications for the infants and children who play in the soil, and artisanal miners, mostly young men, who are at higher risk of Pb exposure. Thus, urgent interventions are required to reduce Pb exposure in the affected townships, and close monitoring is required to enable early detection of clinical signs related to Pb toxicity with medical intervention.
Kabwe town, Zambia, is ranked among one of the world’s most polluted places because of the Pb-Zn mine that operated for almost a century, from 1902 to 1994, without adequate pollution regulations addressing the potential dangers of Pb. As a result, although the mine is no longer active, the residue left behind and illegal activities around the mine have contaminated the soil and poisoned a generation of children. Thus, to address the contamination status of Pb pollution in Kabwe, blood samples were collected from a total of 1190 subjects. Blood samples were collected in 13 health centers after obtaining informed consent and completing a questionnaire collecting information on weight, height, age, sex, and socio-occupational category. Blood Pb levels (BLLs) were measured by the Lead Care® II analyzer.
The current study comprises 291 younger children (3 months–3 years old); 271 older children (4–9 years old); 412 mothers (average age of 39 years) and 216 fathers (average age of 46 years). The BLLs ranged from 1.65 to 162 mg/dL, with an overall average Pb level of 20.8 ± 21.4 μg/dL and a median level of 13.0 μg/dL (interquartile range: 1.65–40.3). There were different trends in BLLs among the population. Higher BLLs were found near the mining area, and the differences were significant.
Among the family, children had higher BLL than adults. There was a clear association between age and BLLs. The mean BLL was highest in the under 3 years-old group compared to the other age groups, consistent with the concept that hand-to-mouthing activities are expected to put children of that age at higher risk. In total, sixty-nine percent of the participants had confirmed BLLs of greater than 5mg/dL – a blood Pb reference value that raises ‘health concerns’ according to the CDC.
In summary, there is a potential for Pb poisoning in Kabwe, especially in townships close to the dump. This study revealed Pb exposure in the general population of Kabwe and supports the premise that the Kabwe Pb-Zn mine, closed over 25 years ago, is still the main source of Pb exposure and has poisoned the residents. It raised great concern about its health implications for the infants and children who play in the soil, and artisanal miners, mostly young men, who are at higher risk of Pb exposure. Thus, urgent interventions are required to reduce Pb exposure in the affected townships, and close monitoring is required to enable early detection of clinical signs related to Pb toxicity with medical intervention.