By Shalen Murphy, Saline High School, Saline, Michigan, USA
In 2014, Flint, Michigan made national headlines when researchers discovered that over 140,000 individuals had been exposed to lead and other contaminants in the drinking water (Ruckart et al., 2019). Now, six years and $100 million later, the issue has yet to be completely resolved (Environmental Protection Agency [EPA], 2020). Many Americans view the Flint Water Crisis as a rare catastrophe; however, the incident is a microcosm for a much larger global health crisis: lead exposure. In 2017, lead exposure accounted for 1.06 million deaths, the majority of which were in developing countries (World Health Organization [WHO], 2019).
The most common vehicles for lead exposure are soil, pipes, and paint. Mining for resources like coal releases lead dust into the environment, thus contaminating the air, soil, and drinking water supply. Drinking water is further polluted by lead deposits entering the water as it travels through deteriorating lead pipes (Mayo Clinic, 2019); humans are then exposed via inhalation of air particles or ingestion.
The use of lead paint is also a widespread issue, especially in developing countries where there are few regulations on the ingredients in paint, as it is used on buildings, toys, and playground equipment. Small children, whose brains are still under critical development, are most prone to severe lead poisoning because of their “hand-to-mouth behavior” (WHO, 2019). Once toys with lead paint are put in the mouth, the lead enters the body and causes irreversible damage.
Lead is dangerous because it can pass through the blood-brain barrier (BBB) since it is structurally similar to calcium -- one of the few elements that needs to pass through the BBB to maintain homeostasis. The BBB is a physical barricade around the brain that protects the central nervous system by prohibiting harmful substances from entering the brain (Sanders et al., 2009). Perceiving the lead as calcium, the barrier permits it to pass through, which allows it to disrupt calcium pathways in the brain and cause apoptosis, or programmed cell death. In a healthy body, apoptosis regulates cell growth and keeps the body efficient. In someone with lead poisoning, it leads to the destruction of nervous tissue and disrupts the release and uptake of neurotransmitters (Yarlagadda et al., 2007). Because of these side effects, researchers have determined that there is no safe blood lead level in children (Centers for Disease Control and Prevention [CDC], 2020). The interrupted cell signaling alters nervous tissue and leads to the recognizable symptoms of lead poisoning.
Variation exists among the expressed symptoms of lead poisoning. Minimal lead exposure commonly results in reduced attention span, antisocial behavior, anemia, hypertension, and immunotoxicity. More severe lead poisoning leads to reduced intelligence quotient (IQ), intellectual disability, coma, and even death (WHO, 2019). Additionally, lead exposure can bring about unwanted repercussions for entire nations; unfortunately, the brunt of this issue is concentrated in developing nations.
The World Health Organization estimates that lead exposure causes cognitive degradation in one-third of children globally, and 97% of those affected reside in the developing world (WHO, 2010).
Figure 1 (McCarthy et al., 2020)
This trend exacerbates the cycle of trapping impoverished nations at the bottom of society. Lead exposure often results in lower IQs, which in turn correlates to a lower lifetime earning potential. Additionally, lead exposure creates immense healthcare costs, putting tremendous strain on potentially unstable infrastructures as developing countries attempt to treat the growing number of patients. New York University conducted a study estimating the economic cost of damage from lead exposure. After taking decreased IQs and increased healthcare costs into consideration, the study found that low and middle-income countries (LMICs) spend roughly $977 billion annually. For comparison, the United States spends approximately $50.9 billion (New York University [NYU], n.d.). These consequences are enough to raise concern for any country and make individuals question why the problem remains unsolved.
Figure 2 (NYU, n.d.)
The issue lies in the fact that LMICs lack the organization, financial capital, and workforce to adequately address this problem. As seen previously, the cost of lead exposure is high; however, the cost of completely remodeling the infrastructure to eliminate the lead threat would be even more devastating. Additionally, LMICs are dependent on industries like mining and lead battery recycling to boost their economy, which, in turn, exposes the population to harmful contaminants. Both of these predicaments, among others, complicate the problem and spark discussions over how to eliminate lead exposure in LMICs.
Nonetheless, it is clear that the lead exposure crisis needs to be at the forefront of international discussion. By affecting one-third of children globally, lead exposure is impacting our present as well as dictating our future, and progress will not be made until the lead exposure crisis is resolved. This multifaceted problem will not be solved by one individual alone; however, that does not mean individual efforts cannot be put towards a greater movement. As citizens of countries with wealth and status, it is our responsibility to demand more of our world leaders. Therefore, I humbly ask anyone reading this article to take action. Educate those around you about lead exposure and support organizations, such as the World Health Organization and the Global Alliance to Eliminate Lead Paint, that are dedicated to eradicating this problem. Lead exposure is a growing issue, but by consolidating support, we can eliminate this crisis and contribute to a healthier world.
References
Centers for Disease Control and Prevention. (2020, April 07). Sources of Lead. https://www.cdc.gov/nceh/lead/prevention/sources.htm
Environmental Protection Agency. (2020, November 17). Flint Drinking Water Response. https://www.epa.gov/flint#:~:text=EPA%20Awards%20%24100%20Million%20to,water%20infrastructure%20upgrades%20in%20Flint.
Mayo Clinic. (2019, December 20). Lead poisoning. https://www.mayoclinic.org/diseases-conditions/lead-poisoning/symptoms-causes/syc-20354717
McCarthy, N., & Richter, F. (2020, August 4). Infographic: A third of the world's children are affected by lead poisoning. https://www.statista.com/chart/22456/lead-poisoning-in-children/.
New York University. (n.d.). Economic Costs of Childhood Lead Exposure in Low-and-Middle-Income Countries. https://med.nyu.edu/departments-institutes/pediatrics/divisions/environmental-pediatrics/research/policy-initiatives/economic-costs-childhood-lead-exposure-low-middle-income-countries
Ruckart, P. Z., Ettinger, A. S., Hanna-Attisha, M., Jones, N., Davis, S. I., & Breysse, P. N. (2019). The Flint Water Crisis: A Coordinated Public Health Emergency Response and Recovery Initiative. Journal of public health management and practice : JPHMP, 25 Suppl 1, Lead Poisoning Prevention (Suppl 1 LEAD POISONING PREVENTION), S84–S90.
Sanders, T., Liu, Y., Buchner, V., & Tchounwou, P. B. (2009). Neurotoxic effects and biomarkers of lead exposure: a review. Reviews on environmental health, 24(1), 15–45. https://doi.org/10.1515/reveh.2009.24.1.15
World Health Organization. (2010, December 06). Environment and health in developing countries. https://www.who.int/heli/risks/ehindevcoun/en/
World Health Organization. (2019, August 23) Lead poisoning and health. https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health
Yarlagadda, A., Kaushik, S., & Clayton, A. H. (2007). Blood brain barrier: the role of calcium homeostasis. Psychiatry (Edgmont (Pa. : Township)), 4(12), 55–59.
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