Mexico’s 500-year old tradition of using toxic lead-glazes in pottery is a problem that continues to plague residents to this day.
In our paper “Blood Lead Levels in Mexico and Pediatric Burden of Disease Implications,” published in the Annals of Global Health late last year, we estimated that lead is responsible for an average reduction of 5 IQ points in 15% of the Mexican population, and that the use of traditional artisanal pottery is the main cause.
That paper was published in both English and Spanish in an effort to reach researchers and health experts in Mexico and other parts of Latin America.
Now, the March-April 2015 issue of Salud Publica, a prominent scientific journal in Mexico, has published a letter summarizing the paper, signed by Dr. Martha Maria Tellez-Rojo from the National Institute of Public Health (one of our main research partners in Mexico), and Dr. Jack Caravanos, Pure Earth’s head of research.
This letter is important because it addresses the journal’s readers – primarily Latin American researchers. It points out that while much has been done on the issue through programs like our Barro Aprobado project, a nationwide solution is still pending.
After all, Mexico already has regulations in place to ban lead glazes. And a lead-free alternative is available. All the tools are in place. We just need a national strategy for Mexico.
The letter and the paper are part of our outreach efforts to raise awareness about the issue. Read the original letter in Spanish. Translation below:
Lead exposure: A Pending Task in Mexico
the November edition of the Annals of Global Health magazine, edited by the School of Medicine of the Mount Sinai Hospital in New York, published the article “Blood Lead Levels in Mexico and the Pediatric Burden of Disease”.1 Lead is a broadly studied metal for its toxic effects on practically all the systems of the human body. Children are particularly vulnerable to this exposure, which even in small doses, can have occasionally irreversible, serious health effects. According to the Center for Disease Control and Prevention (CDC), a minimum blood lead level for children to be considered safe does not exist. The silent character of these effects (on neuronal development, intelligence, behavior and attention) makes its early detection difficult.
This article is the result of a systematic review and the analysis of a vast bibliography, including 83 scientific articles published between 1978 and 2010. Articles reporting lead in blood in the Mexican population were included, with main objectives directly related to the study of this metal in a minimum sample of 30 individuals. As a result, this study integrated data from over 50,000 individuals.
Through a meta-analysis, the geometric means of lead in blood for urban and rural populations in Mexico during this period were estimated in 8.85 and 22.24 mg/dl of blood respectively. Since the total elimination of leaded fuel, the BLL’s in urban population were reduced to 5.36 mg/dl. BLL’s in rural population are expected to be considerably higher because of the use of lead-based glazes. The maximum value recommended by the CDC for children under 6 of age is 5 mg/dl and the national average in the United States is 1.2 mg/dl.2 This study estimates that lead is responsible for an average reduction of 5 IQ points in 15% of the Mexican population and more than 820,000 disability adjusted life years (DALYs) related to lead for mild mental retardation in children aged 0 to 4.
This is the first article that estimates the burden of disease related to lead exposure in the Mexican population. It shows the success of the implemented measures to control this exposure and generates evidence of the necessity of controlling the primary source of environmental exposure that remains: lead-glazed pottery, used in food and beverage preparation and consumption.
Since 1991, the Fondo Nacional para el Fomento de las Artesanías (FONART) has coordinated efforts to obtain a lead-free glaze and to promote its use among the artisans. Thanks to its work, lead-free artisanal pottery currently exists in the market, however, its production is limited, considering that more than 10,000 pottery workshops exist, and only a little more than 100 with lead-free production.
Other public and private institutions such as the Comisión para la Protección contra Riesgos Sanitarios del Estado de Mexico (Coprisem), different artisan state houses (casas de artesanos) and other civil society organizations, such as Barro Sin Plomo and Blacksmith Institute (now known as Pure Earth), have programs to eradicate the use of lead in pottery. Unfortunately, such efforts have been localized and have not achieved the required national impact on this serious problem.
In June 2014, the strategy “Barro Aprobado en Morelos” was launched by the Instituto Nacional de Salud Pública, along with the Health Services of Morelos, Blacksmith Institute, and other public and private institutions, with the objective of participating actively in the search for solutions. It is an integral strategy that promotes the production and commercialization of lead-free pottery in the state. This initiative actively invites the restaurants to use only lead-free pottery and exhorts the producers to offer the sodium rhodizonate test to prove that their products are lead free. “Barro Aprobado en Morelos” has awakened the interest of different stakeholders and more and more restaurants and shops have joined the program, which seeks to set the model so that those actions that prove to be effective can then be replicated in the rest of the country.
Many pending tasks exist to solve the problem. An important step is to know its magnitude. To achieve it, it would be highly recommended to establish a routine monitoring mechanism of blood lead levels in pregnant women and children of school age, as it happens in other countries. This would allow the identification and elimination of sources of exposure in relevant periods, and the improvement of the development of intellectual capacities of children in Mexico.
The next national survey of health and nutrition is also a formidable vehicle to learn more about the use of lead glazes and estimate lead levels in the general population.
To eliminate lead use in Mexican pottery, a national strategy that coordinates the efforts of public and private institutions and civil societies is required to promote use of lead-free glazes and protect the potter’s economic activity. Finally, with such convincing evidence, stronger actions must be taken in the monitoring and application of the active regulations that prohibit the use of lead in the production of this type of pottery.
Martha María Tellez-Rojo, DSc,(1) [email protected]
Jack Caravanos, PhD. (2)
(1) Centro de Investigación en Nutrición y Salud, Instituto Nacional de Salud Pública. México.
(2) City University of New York, School of Public Health and Blacksmith Institute. New York, USA.