From Contamination to Consequence: Tracing Donna Lake’s Human Environmental History

Abstract

The Donna Reservoir and Canal System (Donna Lake) in Texas has been a persistent source of environmental contamination for over a century, exposing surrounding communities to dangerous levels of polychlorinated biphenyls (PCBs). Originally built for agricultural irrigation, the system became a recreational fishing site before PCB contamination was discovered during public health investigations in the 1990s. This study examines patterns of demographic vulnerability, evaluates remediation efforts by the U.S. Environmental Protection Agency (EPA), and explores residents’ ongoing challenges related to toxic exposure. Using publicly available demographic data, EPA reports, and previous health assessments, the study analyzes variations in community characteristics by proximity to Donna Lake and reviews the effectiveness of interventions implemented to date. The results show that communities closer to the contamination site are predominantly low-income and Spanish-speaking, and that remediation efforts, although initiated, have been slow and insufficient to fully eliminate health risks. The residents continue to face gaps in risk communication and protection. The findings underscore the lasting impacts of historical contamination on vulnerable populations and highlight the urgent need for more effective, community-centered remediation strategies to address persistent environmental health disparities.

1. Introduction

The Donna Reservoir and Canal System, known locally as Donna Lake, was originally constructed in the early 1900s to support agricultural irrigation across Hidalgo County, Texas [1]. Over the decades, it evolved into an essential water source for the cities of Donna and Alamo and became a popular site for recreational fishing among local residents, particularly those living in nearby colonias [2]. However, what was once seen as a vital community resource gradually became an unseen hazard. In 1991, a public health investigation into a cluster of neural tube defects among infants revealed dangerously high levels of polychlorinated biphenyls (PCBs) in fish harvested from the canal system [2]. The Environmental Protection Agency (EPA) confirmed that PCB concentrations in these fish were among the highest ever recorded in U.S. history, with biological samples from local families verifying significant exposure [1,3].

PCBs, synthetic chemical compounds historically used in electrical equipment like transformers, have long been recognized as persistent organic pollutants with severe health consequences [4]. Exposure to PCBs is linked to an increased risk of cancer and can cause significant damage to the cardiovascular, immune, gastrointestinal, musculoskeletal, and neurological systems [4]. Recognizing the urgent health risks, the Texas Department of State Health Services (DSHS) issued a fishing ban in 1994, prohibiting the possession of fish caught from the Donna irrigation system [5]. Public health campaigns were initiated to warn residents through signage, pamphlets, and informational sessions [6]. However, these efforts were largely ineffective. Language barriers, inconsistent messaging, and poorly designed signage meant that many local, largely Spanish-speaking residents remained unaware of the contamination and continued fishing activities, unknowingly exposing themselves and their families to hazardous toxins [2,7].

Although PCB contamination was identified early, it took the EPA 24 years to trace the contamination to its source—an aging siphon pipe that draws water from the Rio Grande. Constructed in the early 20th century, the siphon had been leaching PCBs into the irrigation system for over a century. This represents more than one hundred years of poisoning, during which generations of Rio Grande Valley families were unknowingly exposed to contaminated fish and water. In 2008, the Donna Reservoir and Canal System was designated a Superfund National Priorities Site, enabling access to federal funding for remediation [8,9]. Subsequent ecological and human health risk assessments confirmed that PCB concentrations in fish tissue were 47 times higher than the threshold considered safe for human health [2]. Initial remediation measures, including a fish kill by electroshock and sediment monitoring, proved inadequate, as fish populations repopulated and continued to bioaccumulate toxic substances, perpetuating public health risks [10].

Government agencies’ responses to the contamination have been marked by delays and missed opportunities [2,7]. While some limited actions were taken, community access to the contaminated reservoir was never fully restricted, and public health messaging remained inconsistent. In the absence of strong and sustained governmental leadership, local advocacy groups and community organizations mobilized to protect residents. Organizations such as Texas Housers and ARISE played pivotal roles in raising awareness, advocating for stronger protective measures, and pressuring federal and state agencies to prioritize community health [11]. Collaborating with the EPA’s Environmental Justice program, they sought to improve bilingual risk communication and promote culturally appropriate outreach strategies [2,6,7,10,11]. Despite these efforts, political shifts, federal budget constraints, and regulatory rollbacks significantly hampered progress after 2016, further highlighting the vulnerability of marginalized communities living near contaminated environments.

Building on this historical context and ongoing environmental health concerns, this study seeks to deepen understanding of exposure risks, potential health impacts, and community challenges linked to PCBs contamination in the Donna Lake area. To achieve this objective, the study systematically addresses the following research questions:

• How does the demographic composition of communities near Donna Lake vary as a function of proximity to the contaminated site?
• What interventions and remediation efforts have been undertaken by the U.S. Environmental Protection Agency (EPA) to mitigate toxic contamination in the vicinity of Donna Lake?
• What are the primary challenges and concerns currently experienced by residents as a result of environmental contamination and toxic exposure?

By addressing these questions, this study makes a significant contribution to advancing understanding of human–environment interactions, specifically how prolonged environmental contamination shapes patterns of community vulnerability, health risks, and lived experiences. It offers a localized case study that illustrates broader systemic challenges faced by populations living near hazardous sites, providing insights that can inform more effective remediation strategies, culturally responsive public health interventions, and risk communication practices that truly reach at-risk populations. In so doing, the study highlights critical pathways by which environmental processes and social structures interact, producing persistent inequalities in exposure, health outcomes, and access to clean, safe environments.

The manuscript is structured as follows: It begins with a literature review that synthesizes existing research on PCB contamination in the Donna Reservoir area, environmental monitoring efforts, and associated environmental justice concerns. This is followed by a detailed description of the materials and methods used for data collection and analysis. The key findings are then presented across three focal areas—demographic patterns in communities surrounding Donna Lake, EPA interventions and remediation efforts, and community challenges and resident concerns related to environmental contamination. The Section 5 situates these findings within the broader context of human–environment interactions and environmental health disparities. The manuscript concludes with a summary of key insights and practical recommendations to inform future research, policy development, and community-led approaches to environmental governance.

2. Literature Review

Polychlorinated biphenyls (PCBs) are synthetic organic compounds once widely used in industrial applications due to their chemical stability and insulating properties. However, their persistence in the environment and capacity to bioaccumulate in the food chain have led to serious public health concerns. Exposure to PCBs has been linked to a range of adverse health effects, including cancer, endocrine disruption, immune dysfunction, and neurodevelopmental disorders [12,13,14]. Although the manufacture and use of PCBs were banned in the United States in 1979, these compounds continue to pose environmental and health threats—particularly in communities located near former industrial sites or where waste disposal practices were historically unregulated.

The Donna Reservoir and Canal System in Hidalgo County, Texas, represents a poignant example of this enduring legacy. Built in the early 20th century to support agricultural irrigation, the reservoir eventually became a critical water source for the cities of Donna and Alamo. Over time, however, it became the focus of growing environmental health concerns. In the early 1990s, a U.S. Environmental Protection Agency (USEPA) investigation into a cluster of neural tube defects among infants in the Lower Rio Grande Valley (LRGV) revealed a staggering 399 mg/kg of PCBs in the filet of a common carp (Cyprinus carpio) reportedly caught in the Donna Main Canal (USEPA 1994; Webster et al., 1999) [14,15] . Subsequent testing by the Texas Natural Resource Conservation Commission (TNRCC) and Texas Department of Health (TDH) confirmed PCB contamination in nearly half of the 50 fish sampled from the reservoir and adjacent waterways, with concentrations ranging from 0.55 to 24 mg/kg [15]. Notably, fish from the Rio Grande—the canal’s water source—did not contain detectable PCBs, suggesting a local contamination source within the reservoir system.

While fish tissue exhibited consistently high levels of PCBs, the environmental sampling of sediment and water told a different story. Most samples showed no detectable contamination, save for a single sediment sample from Hidalgo County Drainage Ditch #2 that contained only trace amounts (0.097 µg/kg) [16]. This incongruity raised important questions about the source and pathway of the contamination. In response, researchers turned to aerial remote sensing technologies to search for unauthorized dumping sites. Using high-altitude color-infrared (CIR) photography and low-altitude digital imaging, Webster and colleagues [16,17] successfully identified numerous solid waste disposal sites near the reservoir—many of which were concealed by vegetation and were inaccessible by foot. Ground surveys confirmed the presence of household and construction waste, reinforcing the hypothesis that improperly discarded electrical equipment may have contributed to the reservoir’s PCB burden.

Beyond the environmental science, the Donna Reservoir case also reveals profound challenges in environmental communication and justice. In their investigative report One Hundred Years of Poison, Ramírez [2] chronicled the lived experiences of residents who continued to fish from the reservoir—often unaware of the health risks. While the Texas Department of State Health Services (DSHS) issued a fish possession ban in 1994 and the EPA listed the site as a Superfund National Priorities List location in 2008, these regulatory actions did not adequately reach or resonate with local residents. Signs posted around the reservoir were frequently vandalized or poorly maintained, and outreach materials were often not translated into Spanish or tailored to the community’s literacy levels. As a result, families continued to engage in recreational and subsistence fishing at the site, unknowingly exposing themselves to toxic contamination. In the absence of effective governmental communication, local organizations such as A Resource in Serving Equality (ARISE) stepped in to bridge the gap, leading grassroots efforts to raise awareness and advocate for remediation.

In 2016, the EPA identified a key source of contamination—a concrete siphon pipe used to channel water from the Rio Grande into the canal system. The pipe’s construction materials contained PCBs, which leached into the water and accumulated in sediment and fish. The EPA’s risk assessments found PCB concentrations in fish to be 47 times higher than levels considered hazardous to human health. Yet despite these revelations, remediation efforts have been slow-moving and community engagement has declined—particularly amid shifting federal priorities and resource constraints [2].

The study by Gracia et al. [18] reinforced these findings by applying geospatial analysis and temporal monitoring to track changes in surface water quality and sediment deposition around the reservoir. Their work highlighted the spatial concentration of contamination near specific structural features, such as a concrete siphon pipe that transfers water from the Rio Grande to the canal system—later identified by the EPA as a significant PCB source. The study stressed the importance of continued surveillance and pinpointed the need for high-resolution mapping and community data to support risk mitigation efforts.

The Donna Reservoir case brings into sharp focus the intersection of environmental contamination, regulatory failure, and social inequity. It illustrates how historically underserved communities—often low-income, Spanish-speaking, and politically marginalized—can bear a disproportionate share of environmental risk. Community-based participatory research (CBPR) conducted by Cantu et al. [19] further highlights the limitations of traditional public health messaging in such contexts. Through focus groups in nearby colonias, the study found that most participants were unaware of the specific health risks associated with PCB exposure, despite ongoing EPA campaigns. Participants cited barriers including language, a lack of trust, and the inaccessibility of health information as key factors contributing to their limited understanding of the risks. Mobile phones and informal social networks emerged as primary sources of health information, signaling a need for more culturally relevant, community-driven communication strategies.

Collectively, these studies and reports underscore the urgent need for integrated, multidisciplinary approaches to environmental risk assessment and communication. The Donna Reservoir is not only a site of chemical contamination—it is also a case study in how structural inequalities, policy failures, and environmental hazards intersect. What remains striking, however, is the absence of a systematic, longitudinal study that quantifies the cumulative risks faced by these populations or evaluates the long-term effectiveness of federal and state remediation efforts. Peer-reviewed scholarship has yet to critically examine the EPA’s historical interventions in this region, leaving a substantial gap in both environmental science and justice research. Without this foundation, policymakers and public health advocates lack the evidence needed to design equitable, community-informed solutions for those most affected.

3. Materials and Methods

3.1. Study Area

The Donna Reservoir and Canal System Site is located south of the city of Donna, Texas, near the United States–Mexico border [3,20]. The site encompasses the 400-acre Donna Reservoir, a network of lateral lined and unlined canals, and associated piping infrastructure. As illustrated in Figure 1, the canal system extends approximately 17 miles northward from the Rio Grande River, with lateral canals branching about 5.6 miles to the east and west [20].

The site is operated by the Donna Irrigation District Hidalgo County Number One (Irrigation District), which supplies drinking water to the city of Donna and the North Alamo Water Supply Corporation and provides irrigation water to the surrounding predominantly agricultural lands. Surface water is pumped from the Rio Grande River approximately one mile downstream of Reynosa, Tamaulipas, Mexico, into the Donna Main Canal. From there, water flows northward by gravity for approximately two miles before reaching the siphon—a 1600-foot-long, 9-foot-diameter concrete pipeline that runs beneath the Arroyo Colorado River. After passing through the siphon, water flows into the Lower West Main Canal Unlined (LWMCU), then transitions into the Lower West Main Canal Lined (LWMCL), which conveys water approximately 1.75 miles north to the Donna Reservoir system [20,21].

The Donna Reservoir, averaging a depth of five feet and capable of storing up to 390 million gallons of water, consists of three primary segments—the East, West, and Northwest Reservoirs. Water flows directly into the West Reservoir and then into the East Reservoir through two conduits beneath South Valley View Road, which separates the two segments. Significant environmental contamination concerns at the site stem from polychlorinated biphenyls (PCBs) detected in fish and sediments within the reservoirs and canals. Investigations identified the siphon and downstream sediments as the primary sources of PCB contamination. Although contaminated sediments were removed during a 2020 remedial action, the Texas Department of State Health Services (TDSHS) maintains a fishing ban under Aquatic Life Order Number 9, prohibiting the taking of aquatic life from the canal and river systems. Despite these restrictions, fishing and the consumption of contaminated fish continue, posing ongoing risks to public health [2,21].

3.2. Methods

This study utilized a mixed-methods approach integrating spatial analysis, documentary research, and field observation to assess the environmental and social impacts of PCB contamination surrounding the Donna Reservoir and Canal System (DRCS).

A Conceptual Site Model (CSM) developed for the DRCS identifies the principal contamination sources, transport mechanisms, exposure pathways, and vulnerable populations affected by polychlorinated biphenyls (PCBs). The primary source of contamination is legacy PCB-laden materials leaching from aging infrastructure, particularly near the siphon system that diverts water from the Rio Grande. The CSM outlines the following four major exposure zones: (1) upstream and adjacent to the siphon, (2) the siphon and downstream canals, (3) the West and East Reservoirs, and (4) the downstream crossover canal system [22] (p. 36).

PCBs are transported primarily via surface water flow and accumulate in fish tissue, making fish consumption a critical exposure pathway. Additional exposure routes include dermal contact with contaminated water or sediment and incidental soil ingestion. Identified at-risk populations include subsistence fishers, recreational users (adults and children), and local residents—each facing different levels of cancer and non-cancer risks depending on exposure frequency and proximity to contamination sources [22] (pp. 36–37).

Health impacts from PCB exposure are most frequently observed within 1 to 3 miles of contaminated sites, particularly where fishing or water-based recreation occurs. Studies in other contaminated ecosystems—such as the Hudson and Fox Rivers—have linked proximity to elevated PCB burdens, developmental disorders, endocrine disruption, and increased cancer risks [23,24]. Within the DRCS, the most intense contamination spans a 5.75-mile section downstream from the siphon outlet, with fish tissue samples recording concentrations as high as 97,000 µg/kg, far exceeding health advisory thresholds [25]. Although no formal epidemiological studies have been conducted in the Donna region, residents within a 6-mile radius are presumed to face heightened health risks due to fish consumption and other environmental exposures.

However, illegal fishing and the unregulated distribution of contaminated fish to local markets and restaurants complicate exposure assessments. These illicit practices can extend PCB exposure to populations beyond the immediate contamination zone, including individuals unaware of the fish’s origin [2]. As a result, a 15-mile radius surrounding the contaminated site may be considered an ingestion exposure zone, particularly in regions where residents rely on locally sourced fish or water. This distance reflects the potential reach of contaminant bioaccumulation through aquatic food chains and the distribution patterns observed in similar PCB-contaminated ecosystems (e.g., the Hudson and Fox Rivers) [23,24].

To investigate the spatial dimensions of exposure and demographic vulnerability, spatial analysis was conducted using ArcGIS Pro (version 3.4). Four concentric distance bands—0–1, 1–5, 5–10, and 10–15 miles—were established from the centroid of Donna Lake (Figure 2). Demographic compositions within each band were calculated using the areal apportionment method [24,25]. These bands were selected to evaluate gradients of environmental risk and social vulnerability, following established approaches in environmental justice and hazard exposure research [26,27]. Shapefiles for census tracts and population characteristics were obtained from the U.S. Census Bureau (2020) [26].

Documentary research played a critical role in this study, involving the systematic review and analysis of primary and secondary sources. These included USEPA site profiles, Records of Decision (RODs), remedial action reports, and public health advisories from the Texas Department of State Health Services [2,28]. Additional materials encompassed technical environmental assessments, community fact sheets, and the peer-reviewed literature. This comprehensive review of documents facilitated a reconstruction of the site’s contamination history, remediation timeline, public health guidance evolution, and the adequacy of agency interventions over time.

Finally, field observations were conducted during a two-day community engagement event organized by the USEPA [29]. Observations of site conditions were supplemented by informal discussions with residents, community leaders, and agency representatives. These interactions provided valuable context and qualitative insight, enhancing the interpretation of community concerns and perceptions regarding PCB contamination and ongoing environmental health risks.

Figure 2. The spatial distribution of population density within 20 miles of the Donna Reservoirs, based on 2020 U.S. Census data. Population counts were calculated at the census tract level and categorized into six density classes. Distance bands (1, 5, 10, and 15 miles) were generated from the centroid of the Donna Reservoir using ArcGIS Pro, and demographic estimates were derived using the areal apportionment method. Major urban centers, including McAllen, Mission, Edinburg, Alamo, Donna, and Weslaco, are identified for reference. (Source: U.S. Census Bureau, 2020 [29]; spatial analysis by author.).

Figure 2. The spatial distribution of population density within 20 miles of the Donna Reservoirs, based on 2020 U.S. Census data. Population counts were calculated at the census tract level and categorized into six density classes. Distance bands (1, 5, 10, and 15 miles) were generated from the centroid of the Donna Reservoir using ArcGIS Pro, and demographic estimates were derived using the areal apportionment method. Major urban centers, including McAllen, Mission, Edinburg, Alamo, Donna, and Weslaco, are identified for reference. (Source: U.S. Census Bureau, 2020 [29]; spatial analysis by author.).

4. Results

The results of this study reveal important insights into the social and environmental dynamics surrounding the Donna Lake contamination site. First, spatial analysis highlights distinct patterns of demographic variation among communities at varying distances from the reservoir, illustrating how proximity to contamination intersects with population characteristics. Second, an examination of EPA interventions and remediation efforts provides a detailed account of the actions taken to address PCB contamination and their effectiveness over time. Finally, community feedback gathered through field observations and documentary analysis identifies persistent challenges and resident concerns related to environmental exposure, public health risks, and the broader impacts of long-term contamination.

4.1. Demographic Variation in Communities Surrounding Donna Lake by Proximity to Contamination

Community Characteristics Surrounding Donna Lake: This section presents a demographic and socioeconomic profile of communities located within one-mile, five-mile, ten-mile, and fifteen-mile radii surrounding Donna Lake, Texas, and compares these zones with the statewide characteristics of Texas (see

Table 1. Demographic, socioeconomic, and housing characteristics within 1-, 5-, 10-, and 15-mile radii of the Donna Reservoir and Canal System Superfund Site, compared to state-level data for Texas. Values are presented in raw counts and corresponding percentages where applicable.

Variables	1-Mile	1-Mile Percent	5-Mile	5-Mile Percent	10-Mile	10-Mile Percent	15-Mile	15-Mile Percent	Texas	Texas Percent
Total population	2208	-	90,378	-	353,769	-	656,335	-	28,635,442	-
Total population 5 years or over	1961	-	81,502	-	319,241	-	598,497	-	26,638,436	-
Total households	616	-	25,587	-	99,778	-	191,256	-	9,906,070	-
White	1742	78.89	75,684	83.74	280,675	79.34	491,815	74.93	19,805,624	69.16
Black	-	-	131	0.15	1218	0.34	3704	0.56	3,464,424	12.10
Color	466	21.11	14,694	16.26	73,094	20.66	164,519	25.07	8,829,819	30.84
Hispanic	1998	90.52	83,585	92.48	330,025	93.29	600,617	91.51	11,294,257	39.44
No schooling completed	22	1.86	1846	3.70	7595	3.84	12,862	3.43	404,398	2.19
Bachelor’s degree or higher	102	8.54	6290	12.61	32,326	16.33	76,742	20.48	5,344,222	28.97
Population speaking only English	353	18.01	14,251	17.49	55,570	17.41	115,129	19.24	17,289,092	64.90
Income at or above poverty level	1214	55.00	61,606	68.16	249,517	70.53	477,210	72.71	24,029,186	83.91
Income past 12 months <$10,000	68	11.05	3230	12.62	11259	11.28	20,743	10.85	591,845	5.97
Income past 12 months between $10,000 and $14,999	44	7.18	2340	9.15	7610	7.63	12,488	6.53	387,297	3.91
Income past 12 months between $15,000 and $19,999	52	8.39	2162	8.45	7629	7.65	13,876	7.26	398,380	4.02
Total housing units	762	-	30,837	-	117606	-	220,526	-	11,112,975	-
Total occupied housing units	616	-	25,587	-	99778	-	191,256	-	9,906,070	-
Owner-occupied housing units	442	71.78	19,080	74.57	67800	67.95	125,728	65.74	6,168,808	62.27
Renter-occupied housing units	174	28.22	6507	25.43	31978	32.05	65,527	34.26	3,737,262	37.73
Built 1939 or earlier	22	2.87	730	2.37	1401	1.19	2506	1.14	384,112	3.46
Built 1940 to 1949	4	0.47	354	1.15	1682	1.43	3358	1.52	358,343	3.22
Built 1950 to 1959	24	3.10	998	3.24	3634	3.09	6546	2.97	854,731	7.69
Built 1960 to 1969	56	7.34	2163	7.01	6606	5.62	11,804	5.35	981,038	8.83
Built 1970 to 1979	90	11.85	2922	9.48	12,505	10.63	25,525	11.57	1,651,689	14.86
Built 1980 to 1989	216	28.35	5861	19.01	19,009	16.16	35,268	15.99	1,772,042	15.95
Built 1990 to 1999	111	14.52	6267	20.32	23,742	20.19	44,609	20.23	1,678,535	15.10
Built 2000 to 2009	202	26.48	8793	28.51	34,902	29.68	64,862	29.41	2,075,148	18.67
Built 2010 to 2013	26	3.40	1368	4.44	6221	5.29	11,793	5.35	572,178	5.15
Built 2014 or later	12	1.62	1381	4.48	7902	6.72	14,255	6.46	785,159	7.07

).

The total population within one mile of Donna Lake is 2208, which increases to 90,378 within five miles, 353,769 within ten miles, and 656,335 within fifteen miles. The number of households follows a similar distribution, ranging from 616 households at one mile to 191,256 at the fifteen-mile mark. Compared to the state of Texas, which has over 28.6 million residents and approximately 9.9 million households, the communities surrounding Donna Lake represent relatively small but demographically distinct populations.

A significant finding is the overwhelmingly high proportion of Hispanic residents in the study area. Within one mile of Donna Lake, 90.52% of the population identifies as Hispanic, and this percentage rises to 93.29% within ten miles, compared to just 39.44% statewide. Conversely, the percentage of Black residents is negligible in the one-mile zone and remains below 1% even within a ten-mile radius, compared to 12.1% across Texas. The percentage of White residents is 78.89% at one mile but declines slightly to 74.93% at fifteen miles, still higher than the state average of 69.16%. Persons identified as “of color” (non-White) comprise only 21.11% in the one-mile zone, lower than the state figure of 30.84%.

Educational indicators reflect marked disparities. Only 8.54% of the one-mile population holds a bachelor’s degree or higher, increasing to 20.48% at fifteen miles. In contrast, 28.97% of Texans hold a bachelor’s degree or higher. The proportion of those with no formal schooling reaches 3.84% within ten miles, notably higher than the state average of 2.19%.

Language use further reveals social vulnerability. In the one-mile zone, only 18.01% of the population speaks only English at home, significantly lower than the state average of 64.9%. This indicates a high prevalence of non-English speakers in the area immediately surrounding Donna Lake, which may limit access to environmental hazard communication and emergency preparedness information.

Indicators of poverty and economic insecurity are pronounced. Only 55% of the one-mile population lives at or above the poverty level, compared to 83.91% across Texas. Moreover, a combined 26.62% of the one-mile population earns less than $20,000 annually, nearly double the corresponding proportion statewide (13.9%). Similar patterns are observed in the surrounding radii.

The majority of households in the one-mile radius are owner-occupied (71.78%), slightly above the state average (62.27%). However, housing stock in this area is older than state averages, with 28.35% of homes built between 1980 and 1989 and only 1.62% constructed in 2014 or later. Older housing may pose risks of structural deficiencies, contamination, or poor indoor air quality, compounding vulnerability in environmental hazard zones.

Evidence of Disproportionate Exposure: The demographic and socioeconomic data within 1- to 15-mile radii of the Donna Reservoir and Canal System Superfund Site in Donna, Texas, reveal disproportionate environmental burdens when evaluated through the lens of the National Environmental Policy Act (NEPA) and the Council on Environmental Quality’s Environmental Justice (EJ) guidance. The surrounding communities are overwhelmingly Hispanic, comprising between 90.52% and 93.29% of the local population, compared to only 39.44% statewide (Table 1). This significant overrepresentation qualifies the area as a minority population under CEQ criteria and triggers environmental justice considerations [30]. Economic vulnerability is also evident—more than 25% of local households earn less than $20,000 annually, with up to 12.62% earning below $10,000—double the statewide rate of 5.97%. Educational disparities compound this vulnerability, with only 8.54% to 16.33% of residents possessing a bachelor’s degree or higher, in contrast to the state average of 28.97%. Furthermore, linguistic isolation is severe; fewer than 19% of residents speak only English, compared to 64.90% statewide, indicating potential barriers to accessing risk communication and participating meaningfully in decision-making processes.

Housing data further reflect structural inequities. A sizable portion of homes in the impact zones were constructed prior to 1980, many of which are associated with aging infrastructure and potential environmental health hazards. Although owner-occupancy rates are relatively high, the condition and age of these units raise additional concerns for disaster resilience and long-term exposure to contamination. Taken together, these intersecting vulnerabilities—race and ethnicity, poverty, limited education, linguistic barriers, and substandard housing—demonstrate the presence of “disproportionately high and adverse” effects, as defined under NEPA and Executive Order 12898 [30]. These findings underscore the urgent need for inclusive, culturally responsive, and linguistically accessible strategies in ongoing remediation and risk mitigation efforts at the Donna Reservoir site [8].

4.2. EPA Interventions and Remediation Efforts at the Donna Lake Contamination Site

It was not until the 1970s and 1980s—approximately 65 to 75 years after its construction—that elevated concentrations of polychlorinated biphenyls (PCBs) were first detected in fish inhabiting the system. Initial fish sampling revealed PCB levels ranging from 0.04 to 0.49 mg/kg, well above health-based safety thresholds [15]. Although monitoring through the National Contaminant Biomonitoring Program documented a modest decline in PCB concentrations between 1976 and 1984—from a geometric mean of 0.89 ppm to 0.39 ppm—fish continued to exhibit dangerously high contamination, with maximum concentrations as high as 70.6 ppm in 1976 and 6.7 ppm still recorded in 1984 [15]. These findings made it clear that contamination was entrenched, yet comprehensive action was slow to materialize (see

Table 2. A chronology of key events related to the construction of the Donna Reservoir and Canal System, the detection of PCB contamination, and the subsequent remediation efforts.

Date	Activities	Category	Reference
1906	Initial Construction of the Donna Reservoir and Canal System (DRCS): The Donna Reservoir and Canal System (DRCS) was constructed to facilitate water distribution for agricultural purposes.	Intervention	EPA Document No. TX0000605363 [8]
1970s–1980s	PCB Concentrations in Fish: Elevated concentrations of polychlorinated biphenyls (PCBs) were detected in fish, with levels ranging from 0.04 to 0.49 mg/kg.	PCB monitoring and detection	TNRCC, 1988 [15]
1976–1984	Trends in PCB Concentrations in Fish: The geometric mean of total PCBs in whole fish was 0.89 parts per million (ppm) in 1976, declining to 0.39 ppm by 1984. The maximum concentration similarly decreased from 70.6 ppm to 6.7 ppm during this period.	PCB monitoring and detection	National Contaminant Biomonitoring Program, US Fish and Wildlife Service (USFWS) [31]
1992	Elevated Rates of Neural Tube Defects and Environmental Studies: An increased incidence of neural tube defects (NTDs) in infants born in Cameron County led to the establishment of the Lower Rio Grande Valley Environmental Study (LRGVES) in 1992.	PCB monitoring and detection	TNRCC, 1998 [15]
1998	Findings from the Lower Rio Grande Valley Environmental Study (LRGVES): The LRGVES contaminant exposure study identified PCBs at 399 mg/kg in a common carp from the DRCS Main Canal, and elevated PCB levels in blood samples from local residents.	PCB monitoring and detection	TNRCC, 2001 [1]
1994	Issuance of Aquatic Life Order Number 9: Following extensive sampling across Hidalgo County and along the Rio Grande, the Texas Department of Health issued Aquatic Life Order Number 9, prohibiting the taking of aquatic life from the Donna Irrigation System.	Remediation efforts	TNRCC, 2001 [1]
2001	Detection of Aroclor-1254 in Sediment Samples: Aroclor-1254 was detected in suspended sediment samples at concentrations ranging from 15 micrograms per kilogram (µg/kg).	PCB monitoring and detection	TNRCC, 2001 [1]
2005	Concentrated Levels of PCBs in Fish: Elevated PCB levels were found in 30 fish samples from the Main Canal and Reservoir, ranging from less than 0.005 µg/kg to 2706 µg/kg.	PCB monitoring and detection	Texas Department of State Health Services (DSHS), 2005 [32]
2008	National Priorities List Designation: The DRCS site was officially listed on the National Priorities List (NPL) in March 2008 due to PCB contamination in sediment and fish.	Intervention	EPA Document No. TX0000605363 [8]
2008	EPA Action Memorandum for Fish Removal: On August 6, 2008, EPA Region 6 signed an Action Memorandum authorizing fish removal operations within the DRCS canal area.	Intervention	EPA Document No. TX0000605363 [8]
2008–2023	Between 2008 and 2023, the EPA conducted eight fish removal operations at the Donna Reservoir and Canal System, extracting approximately 37,605 PCB-contaminated fish to reduce immediate human health risks and support broader remediation efforts.	Remediation efforts	EPA, 2025 [33]
2018	Final Superfund Record of Decision: In September 2018, the Texas Commission on Environmental Quality (TCEQ) received the final Superfund Record of Decision (ROD) for the DRCS site, formalizing the comprehensive remediation strategy.	Remediation efforts	TCEQ, 2018 [28]
2019–2024	Since the 2018 Record of Decision, the EPA has completed multiple phases of remedial design and action at the Donna Reservoir and Canal System, including large-scale sediment removal and site stabilization from 2019 to 2024, with additional remedial activities and monitoring projected through 2026.	Remediation efforts	EPA, 2024 [34]
2022–2023	The EPA completed construction of the sediment removal remedy at the Donna Reservoir and Canal System. Approximately 25,800 cubic yards of PCB-contaminated sediment were removed. Erosion control measures were installed, and long-term monitoring programs were initiated to assess sediment and fish tissue PCB concentrations.	Remediation efforts	EPA, 2025 [10]

).

Public health concerns took center stage in the early 1990s, when an alarming increase in neural tube defects (NTDs) among newborns in Cameron County was reported. This occurred nearly 85 years after the DRCS was first built, and about 20 years after contamination was initially detected. In response, the Lower Rio Grande Valley Environmental Study (LRGVES) was launched in 1992 to investigate potential environmental exposure pathways. By 1998, the LRGVES confirmed the troubling presence of PCBs not only in the aquatic environment—specifically, carp from the DRCS Main Canal with PCB levels as high as 399 mg/kg—but also in the blood samples of residents, providing undeniable evidence of human exposure.

In the wake of mounting evidence, initial protective measures were enacted, including the issuance of Aquatic Life Order Number 9 in 1994, prohibiting the harvesting of aquatic species from the Donna Irrigation System. However, true large-scale remediation efforts would not officially begin until 2008—102 years after construction, nearly 40 years after initial detection, and 16 years after public health concerns were first formally investigated. It was only then that the Environmental Protection Agency (EPA) added the DRCS to the National Priorities List (NPL) under the Superfund program and authorized direct intervention efforts (Table 2, Figure 3).

Between 2008 and 2023, the EPA conducted eight separate fish removal operations under administrative orders, removing approximately 37,605 PCB-contaminated fish to reduce immediate human health risks [20,32,35]. Nevertheless, interim measures alone were not sufficient. A comprehensive, long-term strategy was needed to address the root contamination in sediment and ecosystem structures (Table 2, Figure 3).

In 2018—110 years after the reservoir’s construction—the Texas Commission on Environmental Quality (TCEQ) received the final Superfund Record of Decision (ROD), formally outlining a multi-faceted remediation strategy [36]. Following the ROD, between 2019 and 2024, the EPA embarked on the major phases of remedial design and action, including large-scale excavation and sediment removal. Notably, between 2022 and 2023, the EPA removed approximately 25,800 cubic yards of PCB-contaminated sediment, installed extensive erosion control measures, and initiated long-term monitoring programs to track PCB concentrations in both sediment and aquatic species (Table 2, Figure 3).

Thus, the major environmental cleanup efforts formally began over a century after the system’s construction, about 40–45 years after contamination was first identified, and around 25 years after the connection to serious human health outcomes was recognized [15]. Even today, ongoing monitoring and maintenance are projected to continue beyond 2026, highlighting that full remediation of historical contamination is a multi-generational effort (Table 2, Figure 3).

The environmental and public health saga of the DRCS reflects broader themes common to legacy contamination sites—an initial underestimation of risk, a delayed recognition of health impacts, a slow mobilization of large-scale cleanup operations, and the enduring need for vigilance in environmental stewardship. What began as a triumph of early 20th-century agricultural engineering ultimately necessitated a 21st-century reckoning with environmental pollutants that persist across decades.

Today, the progress achieved at the DRCS offers cautious optimism. It is a testament to the persistence of public health advocates, scientific investigators, and environmental regulators who pressed for long-term solutions. At the same time, it serves as a powerful reminder—investments in environmental health protection must be proactive, not reactive, to prevent future generations from inheriting the burdens of past industrial practices.

4.3. Community Challenges and Resident Concerns Related to Environmental Contamination and Toxic Exposure

It may be argued that many low-income and marginalized communities across the U.S. experience deteriorating infrastructure, water quality concerns, and limited access to public services—conditions that are not unique to the area surrounding Donna Lake. While this broader pattern is well documented, such a view oversimplifies the severity and specificity of the environmental risks faced by Donna residents. Unlike other communities where water system mistrust may stem from outdated infrastructure or esthetic water quality issues, the residents of Donna live adjacent to a federally designated Superfund site contaminated with polychlorinated biphenyls (PCBs). Here, the threat is not hypothetical or perceptual—it is rooted in decades of measurable contamination, confirmed through environmental sampling, risk assessments, and evidence of human exposure. This distinction underscores the need to evaluate Donna not merely as an underserved area, but as a community confronting a unique and compounded environmental health crisis.

Communities surrounding Donna Lake—including nearby colonias and disadvantaged unincorporated neighborhoods—face a constellation of environmental and social vulnerabilities that profoundly impact their health, daily routines, and long-term well-being [37,38]. While it is true that issues such as infrastructure disrepair, poverty, and mistrust in public services are common in many underserved regions across the country, Donna Lake presents a particularly concerning case due to the overlapping burden of proximity to a PCB-contaminated Superfund site.

At the core of community concern is a persistent mistrust in water quality and safety. Although most homes are connected to public water systems, residents frequently describe their tap water as discolored, odorous, and associated with adverse health effects, including skin irritation, gastrointestinal discomfort, and long-term illnesses [37,38]. These experiences—while echoed in other marginalized areas—are intensified in Donna by the site’s contamination history and lack of timely remediation.

During a community site visit on 28 March 2019, residents shared firsthand accounts of flooding, deteriorating housing, and insufficient access to waste management and sewage services [4]. While such conditions are unfortunately common in under-resourced communities, their public health consequences in Donna are heightened by the presence of legacy PCBs. Although PCBs typically bind to sediment due to their hydrophobic nature, they continue to bioaccumulate in fish and may be remobilized during flooding events—posing risks through direct contact, ingestion, or the consumption of contaminated food [22,23,39]. These routes of exposure link visible infrastructural degradation with toxicological threats, creating a heightened-risk environment not present in all comparable regions.

While challenges like substandard housing and solid waste accumulation are not unique to Donna, their interaction with environmental contamination complicates the local risk profile. Residents living in flood-prone, poorly constructed housing are particularly vulnerable to exposure when floodwaters carry PCB-laden sediment into yards and homes. Additionally, the reliance on the open burning of trash, common due to limited waste collection, contributes to air quality issues that may exacerbate underlying health conditions but are not directly attributable to PCBs [37,38]. These indirect but compounding risks require careful framing to ensure the discussion remains focused on the study’s environmental health objectives.

What distinguishes Donna most clearly is the continued illegal fishing and consumption of fish from the contaminated lake. Despite public warnings, legal restrictions, and Superfund designation, residents—often driven by necessity or unaware of the risks—continue to fish in Donna Lake. These fish have been repeatedly shown to contain dangerously elevated PCB levels, posing substantial health risks including cancer, endocrine disruption, and neurodevelopmental harm [6,8,15]. The situation is made more alarming by reports from local advocacy groups such as ARISE Adelante that some of this contaminated fish may be entering the informal local market and restaurant supply chains [11,40].

Thus, while some community challenges may mirror those found in other low-income areas, the specific risk pathways tied to environmental PCB exposure—particularly through contaminated fish and sediment—make Donna Lake a distinct and urgent case. The long-standing awareness of these risks by federal and state officials, without corresponding effective enforcement, further underscores the environmental injustice facing this community [37,38].

Ultimately, the cumulative impact of both general and site-specific vulnerabilities manifests in serious public health concerns, with residents reporting elevated rates of cancer, respiratory illnesses, and developmental issues among children [2,7]. These outcomes reinforce the need to distinguish between broader socioeconomic challenges and those uniquely intensified by environmental contamination.

Despite these challenges, community organizations such as ARISE Adelante continue to respond with resilience and action. Through advocacy, education, and direct engagement with residents, they work to amplify community voices and push for equity in environmental health and infrastructure policy. Their efforts exemplify how community-based leadership plays a crucial role in advancing environmental justice, particularly in places like Donna Lake where institutional responses have been slow and uneven.

4.4. Health Impacts and Neural Tube Defects in Communities near Donna Lake

PCBs were first documented in the Donna Canal in 1993 by the U.S. Environmental Protection Agency (USEPA) as part of a broader environmental assessment of the Lower Rio Grande Valley. The EPA collected and analyzed cooked fish samples from nine local households, along with blood and urine samples from individuals who consumed the fish regularly. One carp filet—caught from the Donna Canal—contained 399 mg/kg of PCBs, exceeding adult health risk thresholds more than 1500-fold. Corresponding blood tests revealed elevated PCB concentrations in the individuals tested [41,42].

According to the EPA’s human health risk assessment, distinguishing risks from environmental PCB mixtures requires consideration of the varying potency of commercial formulations, along with environmental factors such as persistence and bioaccumulation. Notably, PCBs that accumulate through the food chain exhibit higher toxicity than their commercial counterparts, meaning that dietary exposure—particularly through fish consumption—can pose greater health risks than standard risk assessments might predict [43] (p. 35).

In 1991, a public health investigation into a concerning cluster of neural tube defects (NTDs) among infants revealed dangerously high levels of polychlorinated biphenyls (PCBs) in fish harvested from the Donna Reservoir and Canal System [15]. The Environmental Protection Agency (EPA) confirmed that the PCB concentrations found in these fish were among the highest ever recorded in U.S. history, with biological samples from local families providing evidence of significant exposure [1,2]. These alarming findings raised immediate public health concerns regarding the potential link between environmental contaminants and birth defects in the region. While some epidemiological studies report limited direct associations, extensive experimental and human evidence strongly supports the biological plausibility that PCB exposure disrupts early neural development and may contribute to the elevated rates of neural tube defects (NTDs) observed in affected communities [4].

Decades later, communities in the vicinity of Donna Lake and the broader Rio Grande Valley continue to face serious public health challenges associated with elevated incidences of NTDs, specifically encephalocele, spina bifida, and anencephaly [44]. Recent data from the Texas Department of Health (2011–2020) highlight troubling patterns in Hidalgo and Cameron Counties, showing notably high prevalence rates compared to other Texas counties [1,44].

Encephalocele, a severe birth defect in which the brain and membranes protrude through a skull defect, remains a critical concern, with Hidalgo County ranking third-highest statewide (Figure 4A,D) [44,45]. While Cameron County does not rank among the top counties for encephalocele, the heightened incidence in neighboring Hidalgo County underscores a disturbing regional health pattern warranting closer scrutiny.

Additionally, spina bifida—a condition characterized by the incomplete development of the spinal cord leading to significant lifelong disabilities—presents another major public health burden. Cameron County ranks fifth and Hidalgo County ranks sixth among all Texas counties for spina bifida prevalence (Figure 4B,E) [44,45]. These elevated rates, which may be compounded by ongoing environmental harms in the region, profoundly affect the lives and well-being of families in these communities [44,45].

Perhaps most alarming is the prevalence of anencephaly—a devastating neural tube defect characterized by infants born without major portions of the brain and skull. Cameron County exhibits the highest prevalence of anencephaly in Texas, while Hidalgo County ranks fifth (Figure 4C,F) [44,45]. Such extreme rates strongly indicate that persistent environmental exposures, potentially including PCBs and other contaminants identified at Donna Lake, continue to disproportionately impact these communities.

The sustained prevalence of neural tube defects in the Rio Grande Valley underscores the critical need for comprehensive public health interventions, environmental remediation, and community education. Furthermore, it highlights an urgent requirement for ongoing research to better understand environmental determinants of health disparities, and for policy action that addresses and mitigates these severe health outcomes affecting vulnerable populations near Donna Lake.

It is important to acknowledge that limited data availability at the individual or census tract level poses a challenge in directly establishing a causal link between PCB contamination and NTD rates [46]. Nevertheless, the consistently elevated rates of NTDs in the surrounding areas underscore the need for continued public health attention and further investigation.

5. Discussion

This study provides critical insights into the intersection between environmental contamination, social vulnerability, and community health risks in the areas surrounding Donna Lake, Texas. The results are discussed below in three interconnected subareas, each addressing key findings from the analyses and interpreting their implications in relation to previous studies and existing knowledge.

5.1. Demographic Variation by Proximity to Donna Lake

The communities surrounding Donna Lake tell a clear and compelling story—one of concentrated disadvantage and long-standing vulnerability. Within just one mile of the contaminated site, more than 90% of residents identify as Hispanic, and over a quarter earn less than $20,000 a year. Fewer than 9% have completed a bachelor’s degree, and less than one in five speak only English at home. These figures are not just statistics—they represent real people living with limited resources, restricted access to opportunity, and heightened exposure to environmental risks.

As we move farther from the lake, these patterns shift only slightly. The same structural challenges—poverty, low educational attainment, language isolation—persist across the five-, ten-, and even fifteen-mile zones. What we see is a region shaped by more than geography. It has been shaped by decades of underinvestment, marginalization, and limited access to basic infrastructure and environmental protections.

This concentration of disadvantage also amplifies vulnerability. When households face overlapping challenges—older housing, lower income, limited education, and linguistic barriers—their ability to prepare for, respond to, and recover from environmental hazards is significantly compromised. And in the case of Donna Lake, where contamination is layered atop these existing hardships, the burden becomes even heavier.

Within a 1-mile radius of Donna Lake, residents face a convergence of risks that extend beyond proximity to a Superfund site. Housing data show that a significant share of homes in this area was built during or prior to the era when PCBs were widely used in building materials and public infrastructure. Specifically, over 25% of the housing units in the 1-mile zone were built before 1980, with 7.3% constructed in the 1960s and another 11.9% in the 1970s—decades when environmental regulations were limited and PCB usage was still common (Table 1) [38,43]. These older homes are more likely to be structurally vulnerable and located near contaminated waterways or flood-prone zones, where PCB-laden sediments can be mobilized into living spaces during storm and flooding events [47].

Economic disadvantage further intensifies exposure risks. Nearly 11% of the households within 1 mile of Donna Lake earn less than $10,000 annually, and more than 26% earn under $20,000—figures that far exceed the state average. These income constraints often push residents toward subsistence fishing, even in the face of longstanding advisories against consuming fish from the contaminated reservoir (Table 1) [2,6]. Educational and language barriers compound this vulnerability. Only 8.5% of the residents within the 1-mile zone hold a bachelor’s degree or higher, and fewer than 18% speak only English at home—compared to nearly 65% statewide (Table 1) [38]. This makes it less likely that health advisories, often issued in technical language or without culturally relevant outreach, are effectively communicated or understood [19,48]. (Cantu et al., 2016; Morello-Frosch et al., 2002).

Taken together, these intersecting challenges—aging infrastructure, limited income, lower educational attainment, and linguistic isolation—create a disproportionately high-risk environment for residents living closest to Donna Lake. These households are not only more exposed to PCB-contaminated pathways through water and sediment but are also structurally disadvantaged in their ability to avoid, recognize, or respond to environmental health threats. This intersection of physical and social vulnerability reinforces the need to view environmental contamination not only as a technical hazard but as a deeply embedded issue of environmental justice.

5.2. EPA Actions and Remediation at Donna Lake

The history of EPA actions at the Donna Reservoir and Canal System reveals a troubling pattern of delayed intervention despite early regulatory awareness of polychlorinated biphenyl (PCB) contamination. Although elevated PCB concentrations were first detected in the 1970s and 1980s, and the site was officially listed on the National Priorities List (NPL) in 2008, effective large-scale remediation efforts were slow to materialize. The timeline from contamination detection to substantial remedial action spanned decades, during which time public health risks remained inadequately addressed.

While the fish removal operations initiated between 2008 and 2023 and the large-scale sediment remediation activities formalized under the 2018 Record of Decision (ROD) reflect important regulatory steps, these efforts were hampered by longstanding gaps in enforcement, compliance, and community engagement. Despite the removal of approximately 37,605 contaminated fish and 25,800 cubic yards of PCB-laden sediment, the effectiveness of remediation was constrained by continued uncertainties regarding the primary contamination sources. Notably, the underground siphon—initially identified as a potential source of persistent contamination—remained in place without full replacement or comprehensive mitigation, leaving critical infrastructure vulnerabilities unresolved.

These findings echo patterns observed in broader Superfund site remediation literature, where the lack of early, decisive action and insufficient source control frequently undermine long-term environmental and public health outcomes [49,50,51,52,53,54]. Successful remediation typically hinges on the following three pillars: timely intervention to prevent deep entrenchment of pollutants; clear and comprehensive identification and elimination of contamination sources; and sustained, culturally resonant community engagement that builds trust and encourages protective behaviors.

At Donna Lake, the protracted delays and incomplete source remediation illustrate the consequences of missing these key elements. Moreover, limited public communication and outreach have perpetuated misunderstandings about the risks and remediation progress, particularly among vulnerable local populations historically dependent on the reservoir’s resources.

Taken together, the case of the Donna Reservoir and Canal System underscores the urgent need for more robust environmental governance practices. Future efforts must prioritize early intervention, infrastructure modernization, and community-centered educational initiatives to ensure that public health protection is not an afterthought but a proactive commitment. Without these improvements, the lessons from Donna risk being repeated at other legacy contamination sites, prolonging environmental and human health harms across generations.

5.3. Community Challenges and Health Concerns from Environmental Contamination

Residents living near Donna Lake continue to face a constellation of challenges stemming from chronic environmental contamination. Key concerns include persistent distrust in local water quality, frequent flooding exacerbated by inadequate stormwater infrastructure, structurally deficient housing vulnerable to environmental hazards, and insufficient solid waste management systems. These issues mirror patterns documented in previous research on infrastructure deficiencies and public health risks in colonias across the Rio Grande Valley.

A particularly alarming and persistent issue is the continued illegal fishing and consumption of PCB-contaminated fish from Donna Lake, despite longstanding prohibitions [2,5]. This ongoing behavior signals serious shortcomings in regulatory enforcement and risk communication, especially within socioeconomically disadvantaged communities. The disconnect between regulatory directives and community practices underscores the pressing need for culturally appropriate educational outreach, strengthened enforcement mechanisms, and community-engaged solutions that account for local knowledge and lived realities. These public health concerns are magnified by a growing body of evidence linking dietary exposure to PCBs with adverse neurodevelopmental outcomes [49,50,51,52,53,54]. Maternal consumption of contaminated fish has been associated with reduced birth weight, cognitive impairments, and developmental delays in children. Emerging research also suggests a possible association between PCB exposure and neural tube defects (NTDs), although further investigation is needed to clarify the causal mechanisms [49,50,51,52,53,54]. Emerging research has identified a concerning association between exposure to polychlorinated biphenyls (PCBs), particularly through the consumption of contaminated fish, and the risk of neural tube defects (NTDs) such as encephalocele, spina bifida, and anencephaly [55,56]. Given these risks, promoting safe dietary practices among women of reproductive age in PCB-contaminated regions is essential to mitigate possible teratogenic and neurodevelopmental effects [57,58,59]. Together, these findings reinforce the urgent need for both improved community-level interventions and expanded scientific inquiry into the neurodevelopmental risks posed by persistent PCB exposure through fish consumption.

Compounding these environmental challenges, health data from 2011 to 2020 reveal persistently elevated rates of neural tube defects (NTDs) in Hidalgo and Cameron counties, including encephalocele, spina bifida, and anencephaly [44,45]. These findings align with earlier environmental health investigations from the 1990s, which identified potential links between PCB exposure and increased risks of congenital abnormalities [2,7,15]. The ongoing prevalence of severe birth defects points to a public health crisis likely rooted in long-term environmental exposure [55,56,57,58,59]. Notably, the affected communities are predominantly Hispanic, and evidence indicates that Hispanic women in the United States are at a higher risk of NTD-affected pregnancies compared to women of other racial and ethnic backgrounds. Despite overall declines in NTD prevalence following folic acid fortification, disparities persist, partly due to the lower intake of fortified grains among Hispanic women [60]. Hispanic women in the United States have been found to be at significantly higher risk for anencephaly-affected pregnancies, with one study reporting a 45% increased likelihood compared to White women [61]. National survey data further confirm that Hispanic populations consistently exhibit higher rates of neural tube defects [62]. These findings highlight the need for culturally targeted prevention efforts.

Addressing these health disparities requires a sustained, multi-pronged approach—comprehensive environmental remediation, targeted public health interventions tailored to community needs, and expanded epidemiological research to more conclusively establish causal pathways and develop effective risk mitigation strategies.

5.4. Broader Implications and Future Research Directions

Taken together, these findings illustrate a complex interplay between environmental exposure, social vulnerability, regulatory effectiveness, and health outcomes. This complexity highlights the importance of integrated, multidisciplinary approaches to addressing environmental injustice, particularly in socioeconomically marginalized regions. Future research should focus on rigorously quantifying the health impacts directly attributable to PCB and other toxic exposures through comprehensive epidemiological studies. Additionally, longitudinal investigations would provide valuable insights into chronic health effects associated with sustained environmental exposures.

Given the challenges identified in enforcement and community compliance, future research should also prioritize community-engaged methodologies that integrate local knowledge, involve residents in decision-making processes, and enhance trust in public health interventions. Enhanced investment in community infrastructure, targeted remediation efforts, and culturally relevant health education programs represent critical next steps toward mitigating existing health disparities and building more resilient communities around Donna Lake.

In conclusion, the findings of this study underscore an urgent need for comprehensive environmental remediation, equitable infrastructure investments, strengthened regulatory oversight, and targeted public health initiatives to protect vulnerable communities from ongoing and future environmental health risks.

6. Conclusions

The case of Donna Lake illustrates the deeply intertwined nature of environmental contamination, social vulnerability, and public health disparities. Spatial analysis confirmed that communities most affected by PCB contamination are predominantly low-income and Hispanic, exemplifying persistent patterns of environmental injustice seen across the United States. Although EPA interventions have led to important remediation efforts, persistent gaps in enforcement, infrastructure renewal, and public engagement have limited their overall effectiveness.

The challenges faced by these communities—the mistrust of local water systems, insufficient infrastructure, continued reliance on contaminated fish, and elevated rates of neural tube defects—are not isolated incidents but are symptomatic of broader systemic inequities. Addressing contamination without simultaneously addressing the structural conditions that perpetuate risk leaves vulnerable populations exposed and reinforces cycles of environmental harm.

Future efforts must extend beyond technical remediation. Longitudinal epidemiological research is urgently needed to clarify the health consequences of chronic PCB exposure, while community-based participatory initiatives must be prioritized to rebuild trust, foster resilience, and ensure that interventions are culturally and contextually relevant. Comprehensive remediation, equitable infrastructure investment, and sustained public health outreach are essential steps toward environmental justice.

The experience at Donna Lake serves as a powerful reminder that remediation alone cannot undo decades of environmental marginalization. True progress demands proactive, systemic reforms that embed environmental justice at the center of national environmental policy—ensuring that all communities, regardless of race or income, have the right to a safe, healthy environment.