capstone thesis

Systemic Water Inequality in the Age of Globalization: An Interdisciplinary Examination of Race and Water Contamination from Mexico to California.  

Submitted in partial fulfillment of the Bachelor of Arts requirements in Interdisciplinary Studies (UGIS), The University of California, Berkeley.
Advisor: Professor Amm Quamruzzaman
May 8, 2023

During my time at UC Berkeley from 2019 to 2023, I majored in Berkeley's unique Interdisciplinary Studies Field (ISF), which allowed me to merge various academic perspectives and tackle complex social and environmental issues. My thesis, “Systemic Water Inequality in the Age of Globalization,” examines how race and water contamination intersect across the Mexico-California border. I delve into the role globalization plays in deepening systemic inequalities, highlighting how marginalized communities are disproportionately affected by these environmental challenges. This research was an opportunity to combine my passions for environmental justice, social equity, and global issues, shedding light on the disparities in water access and quality. 

Below is the full thesis in a PDF and also summaries of selections demonstrating my strengths as a researcher and writer. 

My thesis examines the intersection of water contamination, health, and immigration, focusing on Mexico and California. I begin with an alarming statistics- nearly half of U.S. adults and a quarter of children do not drink tap water, with higher rates among minority and low-income populations. In agricultural regions like California’s San Joaquin Valley, where Mexican immigrants make up a majority of the population, disparities in environmental and individual health are evident. Within these communities are compounding factors such as systemic, economic, and historical disinvestment inequalities.

I explore the broader context of water inequality by tracing its roots to colonial exploitation in Mexico, where resource extraction continues to harm local populations. Mexican immigration to the U.S., particularly to California, is often driven by poverty and lack of opportunities, yet leads immigrants to areas vulnerable to water contamination. Using California as a case study, the research questions how water contamination impacts health and whether these disparities are influenced by dependency regimes, socioeconomic status, and immigration status.

I delve into both the historical and contemporary factors shaping immigration patterns and water inequality. While much of the focus is on California, I also seek to understand Mexico’s struggles with water regulation and contamination. The goal is to contextualize the "American Dream" through a critical lens, examining the health outcomes of immigration and the realities of water access in both countries.

My literature review discusses the multidimensional nature of water inequality, focusing on its connection to socioeconomic status, institutional power, and geography. In the context of Mexico, author Darcy Tetreault’s research explores how increasing material extraction rates from the 1990s to 2018, exacerbated socio-environmental conflicts. This trend coincided with the privatization of natural resources and intensified local resistance, especially among rural communities. I also include studies illustrating how foreign mining investment in Latin America have compounded social and environmental issues, especially in communities where land rights and local relations are fraught with tension.

In California, particularly in agricultural areas like the Central Valley, water inequality is more prevalent among certain races and those that are impoverished. Research by Justin McBride on mutual water systems in Los Angeles County highlights the exploitation of immigrant, low-income communities, with private water companies failing to provide clean drinking water. McBride's study reveals how water management issues are compounded by historical segregation and economic exploitation, particularly in unincorporated, rural areas where residents have limited access to resources.

The impact of water contamination on public health is also prominent in the literature. Studies like Sarah Brown Blake’s show how agricultural runoff, especially from dairy farms, has worsened water quality in the San Joaquin Valley, potentially harming maternal-child health. Other studies on nitrate contamination have linked polluted water sources to adverse birth outcomes, reinforcing the disproportionate impact on communities of color. Furthermore, exposure to heavy metals like arsenic and cadmium has been found to increase the risk of cardiovascular disease, illustrating the broader health implications of water inequality.

The concept of environmental racism, as discussed in the work of Christopher J. Schell and his colleges, highlights how racial and socioeconomic disparities in urban environments, are driven by structural factors like redlining and segregation. These disparities are exacerbated by climate change- water quality and availability issues following in suite. Droughts in the San Joaquin Valley have disproportionately affected farmworkers, as shown by Christina Greene’s study, which emphasizes the not only the individual impacts of drought in rural communities, but the larger issues of water availability. 

Data Sources

I sourced the data for California's demographic and water contamination levels from the CalEnviroScreen 4.0 which uses data collected from the years 2014 to 2018. The CalEnviroScreen was developed by the Office of Environmental Health Hazard Assessment (OEHHA) within the California Environmental Protection Agency. It is an expansive and impressive collection of data evaluating environmental pollutants, population vulnerable to pollutants, and socio-economic demographics at the census tracts level.

Variables and Indicators

1. Low Birth Weight (LBW)

LBW is a marker of health risks, associated with chronic issues and infant mortality. It is influenced by environmental exposures like lead, air pollution, and pesticides. I used CalEnviroScreen 4.0. data, which they sourced from California birth records analyzed by Tracking California, a public health institute.

2. Cardiovascular Disease (CVD)

CVD is a leading cause of death globally.  I used CalEnviroScreen 4.0. data which consisted of  age-adjusted rates of emergency visits for acute myocardial infarction (AMI) averaged between the years 2015 and 2017.

3. Drinking Water Contaminant Index

This index assesses the presence of contaminants in public drinking water, factoring in violations of the Maximum Contamination Level (MCL) and Total Coliform Rule (TCR). The CalEnviroScreen 4.0. calculates final score, reflecting combined percentile values for contaminants across California's census tracts.

4. Poverty (% Below 2X Poverty Level)

Poverty is a significant social determinant of health. Areas with higher poverty levels face more exposure to pollutants and psychosocial stressors. I used CalEnviroScreen 4.0. data which came from the US Census Bureau's American Community Survey.

5. Unemployment (% Unemployed)

   Unemployment contributes to poor health outcomes due to reduced healthcare access and increased vulnerability to environmental hazards. This indicator is based on data from the American Community Survey.

6. Race/Ethnicity

  Race and ethnicity data from the 2015-2019 American Community Survey were used to assess environmental health disparities.

Methodology

For my analysis, I used linear regression to examine the relationship between water contamination and health outcomes like LBW and CVD. I built 3 models, each building upon the previous one by adding more covariates:

• Model 1: Examines the effect of water contamination alone.

• Model 2: Adds socioeconomic factors (poverty and unemployment).

• Model 3: Further adjusts for racial composition.

The results of these models are presented in the results section. 

Limitations

For my analysis, I had to assume that the average water quality data is representative, though individual water systems and private wells may have different contamination levels.

Descriptive Statistics

The mean values for most variables are around 50, as they are expressed in percentiles. The race variables reflect the average representation of each racial group in California's census tracts.

Low Birth Weight (LBW)

Model 1: Drinking water contamination predicts an 11% increase in the LBW percentile.

Model 2: When controlling for other covariates, water contamination is no longer significantly related to LBW. However, poverty and unemployment are significant and positively related to LBW.

Model 3: Controlling for race composition, water contamination, poverty level, and unemployment are significantly positively associated with LBW. The White population is negatively associated with LBW, while the African-American population is positively associated with it. The Hispanic and Asian-American populations do not show statistically significant relationships with LBW.

Key Finding: African-Americans have a significantly disproportionate prevalence of LBW, despite comprising only 8.6% of the sample population in California.

Cardiovascular Disease (CVD)

Model 1: Drinking water contamination predicts a 22% increase in the CVD percentile.

Model 2: After adding other covariates, water contamination, poverty level, and unemployment are all significant and positively related to CVD.

-Model 3: When controlling for race, water contamination, poverty, and unemployment remain significantly positively associated with CVD. The Asian-American population is least affected, followed by the White population, Hispanic population, and lastly, African-Americans, who show no significant association.

Key Finding: All ethnic populations in California experience disproportionate levels of cardiovascular disease, with the African-American population showing no significant statistical association. 

Graphs in Figures 1 and 2 illustrate the regression coefficients and their confidence intervals, highlighting the disproportionate health outcomes, especially for African-Americans with respect to both LBW and CVD.

Data Sources and Methods

For my case study of Mexico, I utilized data from Mexico’s National Water Commission (Conagua) 2021 Water Quality report, covering 2,050 water quality sites, including 665 groundwater sites. It tracks 14 physicochemical and microbiological indicators, such as arsenic, with thresholds ranging from <0.01mg/L (Green, EPA-compliant) to >0.1mg/L (Red, 10x beyond the EPA standard). Arsenic exposure has been linked to health issues such as cardiovascular diseases, skin lesions, and developmental delays. It is especially present in rural areas impacted by industrial pollution.

Industrial Context

Mexico’s rich natural resources, especially minerals, drive its economy but contribute to environmental degradation, particularly through mining and agricultural activities. These industries are often tied to foreign capital, with Canada, the U.S., and China being the largest investors. Sonora, a region heavily impacted and defined by both mining and agriculture industries, faces significant water contamination from arsenic seepage, exacerbated by these practices.I chose to focus on the Sonoran regions of aYaqui and Mayo river regions as they heavily rely on subsurface wells for drinking water. Mining and agricultural practices have caused arsenic contamination in these sources, increasing the risk of chronic diseases like cancer.

Geospatial Analysis

The map I produced when I geospatially mapped Mexico’s National Water Commission (Conagua) 2021 Water Quality report data, see Map A below, shows increasing arsenic levels along the Rio Sonora, with areas like Etchojoa municipality and regions near the Rio Guadalupe being particularly affected. My next map, see Map B bellow, highlights arsenic levels in Hermosillo, just southwest of Sonora and was one of the top municipalities for international mineral mining sales in 2022. The results show regions compliant with EPA standards but in proximity to areas with arsenic levels of 0.01-0.03mg/L, up to twice the EPA’s limit. My final map, see Map C bellow, highlights arsenic levels in Hermosillo, just southwest of Sonora and was one of the top municipalities f focuses on the Valle de Mayo aquifer, serving over 72,000 people in the Mayo and Yaqui valleys. Arsenic concentrations in this aquifer are 4-10 times, or more, beyond EPA regulations, indicating severe contamination.

Geospatial Analysis of Mexico

My analysis of groundwater contamination in Mexico, focusing on Sonora, reveals that subterranean arsenic levels are a significant concern, especially in regions impacted by agricultural and mining industries. These industries contribute to not just arsenic, but also other harmful byproducts like lead and nitrates, which require further research to fully understand their effects on health. Advocacy and change is needed for these affected communities to address the environmental and public health risks.

Health Outcomes in California

My results from California show a disproportionate prevalence of low birth weights in African-Americans and cardiovascular disease across all ethnic groups in the sample. One potential explanation for the lower health disparities among Mexicans could be the Hispanic Paradox. Despite facing challenges like poverty, discrimination, and poor healthcare access, Hispanic populations tend to have lower mortality rates than non-Hispanic Whites, living 3-4 years longer on average. This paradox may be due to a combination of factors, including the "healthy migrant" hypothesis, which suggests that immigrants often have a higher level of physical fitness, as well as the socioeconomic and healthcare challenges posed by COVID-19, which affected Hispanic populations disproportionately.

Socio-Cultural Understandings of Healthcare

Personal observations of immigrant families suggest that many first-generation Mexicans prefer returning to Mexico for healthcare due to cost and perceived quality. Mexican healthcare systems like the Instituto de Salud para el Bienestar (IMSS) provide accessible care at a lower cost compared to the U.S. healthcare system. Immigrants often find that healthcare in Mexico offers better doctor-patient relationships, where the focus is on holistic care rather than just treating symptoms. The phenomenon of "medical tourism"- returning to Mexico for care because of exorbitant costs in the U.S.- reflects a socio-cultural understanding that challenges the conventional view of healthcare systems in both countries.

Conclusion

As a body of work, I hope my thesis creates discourse and underscores the complexity of environmental and health disparities both in Mexico and the U.S. The persistence of arsenic contamination in Mexico requires greater focus on industrial impacts, while in California, ethnic health disparities may be better understood through the lens of the Hispanic Paradox and socio-cultural healthcare practices.