How Lead Exposure Holds Latino Children Back in School
Across the country, there is a significant disparity between the educational achievement of Latino and white children. This “achievement gap” is particularly stark in Rhode Island,1 with Latino students scoring significantly lower on standardized tests than non-Latino white students.(a)
Fig. 1 Third Grade Reading Scores in Rhode Island, 2005-2012
Source: Rhode Island Department of Education
(a) Between 1990 and 2009, the Latino student population in the U.S. increased from roughly 6% to 22%,2 with Rhode Island displaying similar growth.3 Yet it wasn’t until 2011 that the federal government began tracking disparities in test scores between white and Latino school children using data from the National Assessment of Educational Progress (NAEP). According to the NAEP data, the national gap in reading and math test scores has declined somewhat since 1990, but remains large, at 22 points out of 500, with similar trends witnessed in Rhode Island over the same period.
(b) The New England Common Assessment Program (NECAP) is a series of subject tests that children take annually in New Hampshire, Rhode Island, Vermont, and Maine. It was developed to meet the requirements of the federal No Child Left Behind Act. The Latino-white gap of 8 points in NECAP test scores represents 67% of a standard deviation in scores.
In the 2012-2013 school year, Latino third graders in Rhode Island scored an average of 40 points (out of 80) on the NECAP reading test, compared to 48 for non-Latino white students.(b) While the gap has been narrowing – from 11 points in the 2005 school year to 8 points in 2012 – it remains large. Math test scores show a similar pattern.
Education experts in Rhode Island and across the country have been working to understand the factors that affect the Latino achievement gap and identify possible interventions to reduce it. Research indicates that, nationally, the higher share of English language learners among the Latino student population (35% versus 9% of non-Latino white fourth graders) and the greater share of Latino children living in poverty (as measured by their eligibility for free and reduced-cost school lunches) accounts for nearly half of the achievement gap.2 The same forces are likely at play in Rhode Island. For example, when only students eligible for free or reduced-price lunches are compared, the gap in NECAP test scores between white and Latino children in Rhode Island falls from 8 to 5 points.
Fig. 2 Latino Children are More Likely to Come from Low-Income Families
Source: Rhode Island Department of Education, National Center for Education Statistics (2011).2
Our research shows evidence of another factor that may play a role in explaining the white-Latino achievement gap in Rhode Island and elsewhere: Latino children’s greater exposure to the environmental toxin lead, which has been shown to affect children’s cognitive development and school performance
Latino children in Rhode Island have higher blood lead levels than non-Latino white children, although, as with test scores, the gap has narrowed in recent years. The disparity in lead levels was 1.3 mg/dL in the 2005-2006 school year. It had fallen by nearly half, to 0.7 mg/dL, by the 2012-2013 school year.
Fig. 3 Early Childhood Lead Levels of Third Grade Students in Rhode Island, 2005-2012
Source: Rhode Island Department of Health
During the period when the disparity in lead levels between Latino and non-Latino white children in Rhode Island was narrowing, the educational achievement gap between the two groups was also shrinking. Our research analyzes whether there is a relationship between these two phenomena.
Text Box 1 Data Used in This Research
The Impact of Lead on Academic Performance
There is a long epidemiological literature documenting the negative impact of exposure to lead on children’s cognitive development. Over the past 20 years, a number of studies have found a significant negative relationship between even low levels of lead exposure (<10 mg/dL) during childhood and cognitive and behavioral outcomes including test scores, IQ, kindergarten readiness, and ADHD/hyperactivity.4
Prior research in Rhode Island found an inverse relationship between the blood lead levels of Providence children in preschool and their school readiness test scores in kindergarten, which are a predictor of later school performance.5 Among children with low lead levels (below 5 mg/dL), 68% scored above the school-readiness benchmark. Meanwhile, only 62% of children with moderate lead levels (between 5 and 9 mg/dL) and 49% of those with high lead levels (10 mg/dL or more) exceeded the benchmark. Our analysis of the relationship between early childhood lead levels and later educational outcomes, such as third-grade reading performance, suggests that this strong negative relationship persists.
The Push to Reduce Lead Exposure
The negative health effects of lead ingestion have been known for hundreds of years, but until the mid-twentieth century, health officials considered only severe cases of lead poisoning to be harmful. This changed in the 1960s, when medical professionals recognized that less acute lead exposure also had harmful effects and began characterizing lead poisoning as epidemic.6
Since the U.S. Surgeon General named lead poisoning a national health problem in 1970, American children’s exposure to lead has declined dramatically, due largely to major regulatory changes eliminating lead from gasoline and household paint.(c) The use of lead in household paint was reduced significantly after World War II (though not in response to any regulatory change) and, in 1978, federal law mandated that all household paint be completely de-leaded. Gasoline was de-leaded more gradually over time, with large reductions in the late 1970s and additional reductions thereafter. By 1996, gasoline was completely lead-free.6
These changes have been credited with drastically reducing lead concentrations in the air, which have declined 99% since 1980. The share of preschool-age American children with elevated lead levels has also declined, especially among the historically high-risk groups of poor and minority (African American and Latino) children.7
(c) The key regulations and legislation that reduced exposure to lead include the 1970 Lead Paint Poisoning Prevention Act, the Clean Air Act, and EPA rules regarding leaded gasoline.
Fig. 4 Share of U.S. Children Under 6 with Elevated Lead Levels, 1997-2013
Source: National Center for Environmental Health (2015).8
Despite these dramatic reductions in the presence of lead in the environment, it remains a significant public health concern due to residual lead in soil and old paint. Disadvantaged children are more likely to be exposed to this lead for two main reasons. First, they are more likely to live in substandard housing built before 1978 or even before World War II, when the lead concentration in paint was considerably higher. A second major source of lead among disadvantaged children is their proximity to high-traffic roadways where residual lead from gasoline emissions is found in higher concentrations in the soil.9
The increased exposure of disadvantaged children to these two sources of environmental lead is driven in part by historical patterns of residential segregation by income, race, and ethnicity that continue to exist in Rhode Island and across the country. Both African American and Latino children are significantly more likely to live in the state’s four major cities – Providence, Central Falls, Pawtucket and Woonsocket – which also boast the greatest share of old housing stock and the highest density of roads and traffic.(d)
(d) Three-quarters of Rhode Island’s Latino and African American children live in these four cities, compared with 13% of non-Latino white children.3
Fig. 5 Latino and African American Children Tend to Live in Older Housing
Source: U.S. Census, 2010-2013
Understanding the Connection Between Lead and Test Scores
The disparity in lead levels between Latino and white children in Rhode Island shrank significantly between 2005 and 2012. During that period, the gap in test scores between these two groups also narrowed. Our research examines whether there is a causal relationship between these two trends
Understanding the relationship between lead levels and test scores is challenging. Children with elevated lead levels tend to be disadvantaged in other ways as well – they are more likely to come from single-parent, lower-income families in high-poverty neighborhoods. All these factors are independently associated with lower test scores, making it difficult to isolate the effects of elevated lead levels. Another issue is collecting accurate data on children’s exposure to lead. Fortunately, Rhode Island is very advanced in its lead testing policies, screening the overwhelming majority of children in the state multiple times.(e)
Rhode Island has a unique set of policies that help us overcome these research challenges. Beginning in the late 1990s, the state required landlords to conduct lead testing and remediation on their rental properties and obtain certificates verifying homes as lead-safe in order to rent them. Our analysis finds that the certificate programs contributed to the reduction in lead levels among Rhode Island’s children during the early 2000s.(f) The programs were particularly effective at reducing lead exposure among Latino and African American children, who are concentrated in the four core cities specifically targeted by the programs.
During the period covered in our dataset, only a portion of the rental homes in Rhode Island received certificates. Because the certificate programs affected some homes but not others, we are able to compare the test scores of children who come from similar socioeconomic and family backgrounds, but differ only in their exposure to lead, depending on whether or not their home was affected by the programs. By controlling for other factors that can play a role in educational achievement, like race, ethnicity, and income, we can isolate the impact of lead exposure on test scores.
(e) While the national rate of child lead screening is closer to 25%, Rhode Island screens roughly 80% of its children. Moreover, most children in the state are screened multiple times in the first six years of life, not just once. This makes Rhode Island a particularly good state in which to estimate the relationship between early childhood lead levels and future educational outcomes. However, the measures are still not perfect, and require assuming that roughly two to three measurements accurately reflect a child’s exposure to lead over the first six years of life.
(f) The certificate programs were still relatively small until about 2005 and all the children in our dataset were born in or before 2005. Only 7% of all children in our dataset lived in a home with a certificate at the time of their first lead test. As a result, the certificate programs were only responsible for a small share of the declines in lead levels we observe in our dataset. Given that the certificate program has since grown, we anticipate that they will be responsible for a greater decline in childhood blood lead levels in the future.
Text Box 2. Rhode Island’s Programs to Promote Lead-Safe Housing
The Effects of Lead on Children in Rhode Island
Our analysis found that for each 1-mg/dL decrease in blood lead levels in children, test scores increase by roughly ½ to ¾ of a point. Based on this finding, we calculate that the 1.9-mg/dL drop in lead levels among Latino children from 2005 to 2012 resulted in a 1.5-point increase in test scores. This means that the decrease in lead levels accounts for roughly 30% of the 5-point increase in test scores witnessed among Latino children in the state over this period.
Looking at the gap between Latino and white children, the disparity in lead levels between these two groups shrank by about 1 mg/dL (from 1.25 to 0.25 mg/dL) from 2005 to 2012, while the gap in test scores narrowed by about 2 points (from 11 to 9). Based on our estimates, the shrinking disparity in lead levels explains 25% of the decline in the educational achievement gap witnessed over this period.
Fig. 6 The Relationship Between Lead Exposure and Test Scores
Source: Rhode Island Department of Education and Department of Health
Looking Beyond Lead
As a result of stronger environmental and housing regulations, Rhode Island significantly reduced the exposure of its children to a harmful toxin. Latino and African American children benefitted the most, and the disparity between their levels of lead exposure and those of white, non-Latino children narrowed. The reduction in child lead levels contributed to improvements in third grade standardized test scores, shrinking the gap between Latino and white students.
These results demonstrate that educational outcomes are not only determined by what happens in the classroom. Interventions into children’s lives outside the classroom can be an effective way to narrow the educational achievement gap between minority and white students. Closing the achievement gap is a complex challenge that involves a number of interacting factors, but reducing lead levels offers one straightforward way to contribute to the solution.
In addition to continuing current efforts to ensure all Rhode Island homes are lead-safe, including fully implementing the state’s lead certificate programs, public health leaders and policymakers might consider other ways to make children’s home lives healthier in order to improve both child health and educational outcomes. While childhood lead exposure is now approaching very low levels thanks to effective state and national policies, other known toxic substances in the environment are not being measured or monitored on a regular basis.(g) Hard metals such as mercury and cadmium, as well as various pesticides, are known to negatively affect children’s cognitive and motor development, but we do not know to what extent these toxins are affecting children in Rhode Island.
The reduction of lead in this country has largely been a success story, and likely contributed to narrowing the educational achievement gap between minority and white students. Future efforts to reduce disparities in child health and educational outcomes could benefit from considering the full range of environmental factors that may affect a child’s development. There may be other toxins holding back children’s educational success in ways we are not even aware of.
(g) The main federal policies that reduced lead exposure were the elimination of lead from gasoline, phased in beginning in 1979, and the elimination of lead from household paint in 1978. Most of the policies dedicated to addressing residual lead in soil (from past gasoline emissions) and in homes (as a result of old paint) have been implemented by individual states. Though states have led the way in reducing residual lead, their efforts have often been supported with federal money from the Department of Housing and Urban Development or, in some cases, legal settlements paid by paint manufacturers.
1. Huguley, James P. (2013). Latino Students in Rhode Island: A Review of Local and National Performances. Bristol, RI: Latino Policy Institute, Roger Williams University.
2. Hemphille, F. Cadell and Alan Vanneman. (2011). Achievement Gaps: How Hispanic and White Students in Public Schools Perform in Mathematics and Reading on the National Assessment of Educational Progress. Washington, D.C.: National Center for Education Statistics, U.S. Department of Education.
3. Rhode Island KIDS COUNT. (2015). Rhode Island Kids Count Factbook. Providence, RI.
4. Canfield, Richard L., Charles R. Henderson, Deborah A. Cory-Slechta, Christopher Cox, Todd A. Jusko, and Bruce P. Lanphear. (2003). “Intellectual impairment in children with blood lead concentrations below 10 mg per deciliter.” New England Journal of Medicine. 248(16): 1517-26. Chandramouli, K., C.D. Steer, M. Eillis, and A.M. Emond. (2009). “Effects of early childhood lead exposure on academic performance and behavior of school aged children.” Archives of Disease in Childhood. 94: 844-848. Lanphear, Bruce P., Richard Hornung, Jane Khoury, Kimberly Yolton, Peter Baghurst, David C. Bellinger, Richard L. Canfield, et al. (2005). “Low-level environmental lead exposure and children’s intellectual function: an international pooled analysis.” Environmental Health Perspectives. 113(7): 894-899. Nigg, Joel, Molly Nikolas, Mark Knottnerus, Kevin Cavanagh, and Karen Friderici. (2010). “Confirmation and extension of association of blood lead with attention deficit/hyperactivity disorder (ADHD) and ADHS symptom domains at population-typical exposure levels.” Journal of Child Psychology and Psychiatry. 51(1): 58-65.
5. McLaine, Pat, Ana Navas-Acien, Rebecca Lee, Peter Simon, Marie Diener-West, and Jacqueline Agnew. (2013). “Elevated Blood Lead Levels and Reading Readiness at the Start of Kindergarten.” Pediatrics. 131(6): 1081-1089. This study uses the same child blood lead level data as the current study.
6. Berney, B. (1993). “Round and round it goes: The epidemiology of childhood lead poisoning, 1950–1990.” The Milbank Quarterly. 71: 3–39.
7. Jones, Robert, David Homa, Pamela Meyers, Debra Brody, Kathleen Caldwell, James Pirkle, and Mary Jean Brown. (2009). “Trends in Blood Lead Levels and Blood Lead Testing Among U.S. Children aged 1 to 5 Year, 1988-2004.” Pediatrics. 123(3): E376-85.
8. National Center for Environmental Health. (2015). “Number of Children Tested and Confirmed BLL's ≥10 µg/dL by State, Year, and BLL Group, Children < 72 Months Old [datafiles].” Atlanta, GA: Centers for Disease Control. Laidlaw, Mark, and Gabe Filipelli. (2008). “Resuspension of urban soils as a persistent source of lead poisoning in children: A review and new directions.” Applied Geochemistry. 23(8): 2021–2039.
9. Laidlaw, Mark, and Gabe Filipelli. (2008). “Resuspension of urban soils as a persistent source of lead poisoning in children: A review and new directions.” Applied Geochemistry. 23(8): 2021–2039.
Does exposure to lead play a role in educational achievement gap between Latino and white children?
Type of Research
- Explores the questions of Policy Leaders by providing a unique academic perspective to the research project
- Provides context for challenging state issues