Associations between PFAS in public water system drinking water and serum among Southern California adults – Nature

Report on the Association Between Per- and Polyfluoroalkyl Substance (PFAS) Contamination in Public Drinking Water and Serum Concentrations in Southern California Adults

Executive Summary

This report details a study examining the link between per- and polyfluoroalkyl substance (PFAS) concentrations in public drinking water and the serum levels of adults in Southern California. The investigation is critically aligned with the United Nations Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation) and SDG 3 (Good Health and Well-being). The study found a significant association, indicating that PFAS contamination in public water systems is a notable contributor to human exposure, even in areas without high-level industrial contamination. Key findings reveal that individuals served by water systems with detectable PFAS, especially perfluorohexane sulfonic acid (PFHxS), had significantly higher concentrations of these chemicals in their blood. When analysis was restricted to post-treatment water data, the association was evident for all modeled PFAS, underscoring the threat to public health and the urgent need for robust water monitoring and regulatory action to achieve sustainability targets.

1.0 Introduction: PFAS Contamination and Sustainable Development Goals

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants that pose a significant challenge to global public health and environmental safety. Their resistance to degradation has led to widespread contamination of drinking water sources, directly undermining the objectives of SDG 6 (Clean Water and Sanitation), which aims to ensure access to safe water for all. Human exposure to PFAS is linked to severe health outcomes, including endocrine disruption, immune suppression, and cancer, creating a direct conflict with SDG 3 (Good Health and Well-being).

While high contamination levels are often associated with industrial manufacturing sites, this study investigates the impact on a general population, highlighting a broader threat to SDG 11 (Sustainable Cities and Communities). The presence of these chemicals, originating from industrial and consumer products, also points to systemic issues in chemical management, relevant to SDG 12 (Responsible Consumption and Production). This report assesses the contribution of public drinking water to PFAS exposure in Southern California, providing critical data to inform policies that protect human health and advance the 2030 Agenda for Sustainable Development.

2.0 Methodology: Assessing PFAS Exposure

The study leveraged data from two primary sources to evaluate the link between environmental contamination and human exposure, reflecting an institutional effort consistent with SDG 16 (Peace, Justice and Strong Institutions) to monitor public health risks.

2.1 Study Population and Serum Analysis

1. Population: The analysis included 563 adult participants from the California Regional Exposure (CARE) biomonitoring study (2018–2020) residing in Southern California.
2. Serum Collection: Blood samples were collected, and serum was analyzed for twelve different PFAS compounds using online solid-phase extraction ultra-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS).
3. Data Linkage: Participant home addresses were geocoded and matched to specific public water system (PWS) service areas.

2.2 Drinking Water Analysis and Exposure Assessment

1. Water Quality Data: PFAS monitoring data from 2019 to 2022 was obtained from the California State Water Resources Control Board (SWRCB). The monitoring primarily targeted untreated source wells near potential contamination sites like airports and landfills.
2. Exposure Indicators: Due to the focus on source water, exposure was categorized rather than quantified. The primary methods included:
   • A binary categorization (any detection vs. no detection).
   • A three-tiered categorization based on the frequency of detection within a water system’s sampling locations (no detection,
   • A sub-analysis focused only on participants (n=235) whose water systems had post-treatment water quality data, which more closely represents finished drinking water.
3. Statistical Analysis: Multivariable regression models were used to examine the association between drinking water PFAS detection categories and natural log-transformed serum PFAS concentrations, adjusting for covariates such as age, sex, race/ethnicity, and income.

3.0 Findings: Link Between Drinking Water and Serum PFAS Levels

The results establish a clear and statistically significant link between PFAS detections in public water systems and elevated serum concentrations in the general population, providing empirical evidence of a public health risk that impedes progress on SDG 3 and SDG 6.

3.1 PFAS Concentrations in Serum and Water

• Serum: PFAS were detected in over 99% of participants. Perfluorooctane sulfonic acid (PFOS) was found in the highest concentration, followed by perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS).
• Drinking Water: Of the 563 participants, 314 (56%) were served by a PWS with at least one PFAS detection. PFOA, PFOS, and PFHxS were among the most frequently detected compounds in the water systems.

3.2 Association Between Drinking Water and Serum PFAS

• Primary Analysis (All Water Samples): A significant association was found for PFHxS. Participants in a PWS service area with at least one PFHxS detection had 31.9% higher serum PFHxS concentrations compared to those with no detections. The effect was stronger for those in areas with a higher frequency of detection (64.0% higher serum levels for ≥50% detection frequency).
• Sub-Analysis (Post-Treatment Water Samples): When the analysis was limited to the 235 participants with post-treatment water data, the associations were stronger and significant for all modeled PFAS:
  • PFHxS: 79.9% higher serum concentrations.
  • PFOA: 30.4% higher serum concentrations.
  • PFOS: 31.2% higher serum concentrations.
  • ∑5 PFAS: 42.0% higher serum concentrations.

4.0 Discussion: Implications for Public Health and SDG Achievement

The findings of this report carry significant implications for public health policy and the pursuit of the Sustainable Development Goals.

4.1 Threat to SDG 6: Clean Water and Sanitation

The study demonstrates that even at low concentrations, PFAS in public drinking water contribute to human body burden. This challenges the fundamental goal of providing safe and clean water for all. The fact that 56% of participants lived in areas with detectable PFAS highlights the widespread nature of the contamination and the scale of the effort required to remediate water sources and protect communities.

4.2 Impact on SDG 3: Good Health and Well-being

The correlation between contaminated water and elevated serum PFAS levels confirms that drinking water is a significant exposure pathway. Given the known adverse health effects of PFAS, this exposure represents a direct threat to public health. According to NASEM guidance, 86% of study participants had serum concentrations high enough to warrant exposure reduction, particularly for sensitive populations. Mitigating PFAS in drinking water is therefore a critical public health intervention necessary for achieving SDG 3.

4.3 Relevance for SDG 11 and SDG 12

This study’s focus on a general population, not one near a major industrial polluter, indicates that the risk of PFAS exposure is a pervasive issue within communities, affecting the goal of creating sustainable and safe urban environments (SDG 11). The contamination stems from the broad production and use of PFAS chemicals, underscoring the need for stronger lifecycle management of chemicals and waste to promote responsible consumption and production patterns (SDG 12).

5.0 Conclusion and Recommendations

This report concludes that PFAS contamination in public drinking water is a significant contributor to serum PFAS concentrations among Southern California adults, even in the absence of high-level industrial pollution. The strong associations observed, particularly for PFHxS and in post-treatment water samples, underscore an ongoing public health risk that directly hinders the achievement of SDG 3 (Good Health and Well-being) and SDG 6 (Clean Water and Sanitation).

To address these challenges and advance the global sustainability agenda, the following actions are recommended:

1. Strengthen and Enforce Regulations: Support the enforcement of federal and state maximum contaminant levels (MCLs) for PFAS in drinking water to reduce public exposure and body burden.
2. Enhance Water Monitoring Initiatives: Continue and expand comprehensive monitoring of drinking water sources, including finished (post-treatment) water, to accurately assess public exposure and identify contamination hotspots. This aligns with the principles of accountability and transparency central to SDG 16.
3. Invest in Water Treatment and Remediation: Provide resources and support for public water systems, especially those serving disadvantaged communities, to implement effective treatment technologies for PFAS removal.
4. Promote Responsible Chemical Management: Advocate for policies that manage PFAS as a chemical class to prevent further environmental contamination, in line with the objectives of SDG 12.

Analysis of Sustainable Development Goals (SDGs) in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

The article on PFAS contamination in drinking water and its effects on human health in California directly addresses and connects to several Sustainable Development Goals (SDGs). The primary SDGs identified are:

• SDG 3: Good Health and Well-being: The core of the article focuses on the health implications of exposure to hazardous chemicals. It investigates the link between PFAS in drinking water and their concentration in human serum, explicitly mentioning adverse health outcomes associated with PFAS exposure, such as cancers, immune suppression, and endocrine disruption.
• SDG 6: Clean Water and Sanitation: The article is fundamentally about the quality of drinking water. It details the contamination of public water systems with PFAS, the monitoring efforts by state authorities, and the challenge of providing safe drinking water to the population.
• SDG 12: Responsible Consumption and Production: The article discusses PFAS as “environmental chemical pollutants” originating from “industrial and consumer applications.” It highlights how these chemicals persist in the environment and contaminate resources like drinking water, which relates to the need for sound management of chemicals and waste throughout their lifecycle to prevent environmental release and human exposure.

2. What specific targets under those SDGs can be identified based on the article’s content?

Based on the specific issues discussed, the following SDG targets are directly relevant:

1. SDG 3: Good Health and Well-being

   • Target 3.9: By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination.
     
     Explanation: The article directly supports this target by investigating the link between PFAS (hazardous chemicals) in drinking water and their accumulation in the human body (serum concentrations). It explicitly states that “Exposure to some PFAS have been associated with a variety of adverse health outcomes including endocrine disruption, immune suppression… and cancers.” The study’s purpose is to understand and mitigate this exposure to prevent such illnesses.

2. SDG 6: Clean Water and Sanitation

   • Target 6.1: By 2030, achieve universal and equitable access to safe and affordable drinking water for all.
     
     Explanation: The study highlights a significant barrier to achieving this target. It reveals that “314 (56%) lived in a PWS service area with at least one PFAS detected in their untreated source water and/or treated drinking water.” This indicates that a large portion of the studied population does not have access to drinking water that is free from these harmful contaminants, making it unsafe.
   • Target 6.3: By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally.
     
     Explanation: The article’s focus on PFAS as “environmental chemical pollutants” that have “persisted in the environment, accumulated in drinking water” directly relates to this target. The monitoring initiatives by the California State Water Resources Control Board (SWRCB) are a direct effort to identify and manage the release of these hazardous chemicals into water sources to improve water quality.

3. SDG 12: Responsible Consumption and Production

   • Target 12.4: By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle, in accordance with agreed international frameworks, and significantly reduce their release to air, water and soil in order to minimize their adverse impacts on human health and the environment.
     
     Explanation: The article identifies sources of PFAS contamination, including “industrial and consumer applications,” “fluorochemical manufacturing plants,” and sites using “aqueous film-forming foams (AFFF), such as military training bases and airports.” This points to the lifecycle of these chemicals and their release into the environment. The study’s findings support the need for better management to reduce their release into water and soil, thereby minimizing their impact on human health.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article mentions and implies several quantitative and qualitative indicators that can be used to measure progress:

1. Indicators for SDG 3 (Target 3.9)

   • Concentration of PFAS in human serum (ng/mL): This is a direct biomarker of exposure to hazardous chemicals. The study measures serum levels of PFHxS, PFOA, and PFOS. A reduction in the geometric mean concentrations of these chemicals in the population over time would indicate progress. The article notes that “86% of CARE participants still had serum concentrations that represent a potential for adverse health effects,” providing a baseline for measurement.

2. Indicators for SDG 6 (Targets 6.1 & 6.3)

   • Concentration of PFAS in drinking water (ng/L): The article provides specific concentration data from water system monitoring. Tracking the average and maximum concentrations of PFAS in public water systems is a key indicator of water quality.
   • Percentage of public water systems (PWS) with PFAS detections: The study found that 56% of participants were in a PWS service area with at least one PFAS detection. Reducing this percentage would be a clear measure of progress towards safer drinking water.
   • Establishment and enforcement of regulatory limits: The article mentions the EPA’s Maximum Contaminant Levels (MCLs) and California’s ‘notification levels’ and ‘response levels’. The adoption, enforcement, and compliance with these health-based drinking water thresholds are crucial policy indicators.

3. Indicators for SDG 12 (Target 12.4)

   • Frequency and level of PFAS detections in water sources near industrial sites: The article mentions that the SWRCB monitored groundwater near potential contamination sources like “airports, landfills, chrome plating facilities, wastewater treatment plants, bulk fuel terminals, and refineries.” Data from this monitoring serves as an indicator of the release of hazardous chemicals from industrial and commercial activities into the environment. A decrease in these detections would signify improved chemical management.

4. Summary Table of SDGs, Targets, and Indicators

Source: nature.com