VPP – Veneto PFAS Project

page updated: 2026/04/22

Motivation

Per- and polyfluoroalkyl substances (PFAS) are highly stable carbon fluorine compounds used since the fifties, among other things, to make products heat and water resistant. These substances, informally known as “forever chemicals,” persist in the environment and can accumulate in the body. The American CDC, in its fourth National Report on Human Exposure to Environmental Chemicals, concluded that “PFAS are found in the blood of people and animals all over the world”. While many recent studies showed robust associations between PFAS exposure and adverse health effects, including among children and newborns, there is currently no clear-cut evidence establishing a causal link. This project is a first attempt at trying to fill this gap by providing credible causal evidence on how PFAS exposure affects cognitive performance, health and labor market outcomes. On top of that, the project examines how areas exposed to PFAS contamination, and residents' behavior, change after contamination discovery.

The project

The original PECHID project, funded for two years as a Marie-Curie Individual Fellowship from Compagnia di San Paolo via Trapezio grant and hosted by Collegio Carlo Alberto, focuses on the effects of PFAS exposure on children development. The VPP project encompasses the initial PECHID project, extending the scope of the analysis to additional outcomes.

Setup

Since the mid-80s, the residents of 27 municipalities located in the Veneto region (Italy) were served PFAS-contaminated water by their local supplier. The environmental incident was discovered only in the summer of 2013, when local authorities intervened and potential PFAS exposure ended. Roughly 140,000 people were thus exposed to PFAS for two decades, making this the largest European case of PFAS contamination. The catchment area of the contaminated water supplier, collectively known as Red zone, was the object of several medical and epidemiological studies. These studies, together with systematic PFAS monitoring of underground water enacted by local authorities, help clarify extent and characteristics of the contamination. 

Research questions

1. The main branch of the project aims to causally assess whether decade-long PFAS exposure in the exposed community affected children's academic performance  [HC], their health [H2], and, among the adult population, mortality [H1], fertility [H3], and labor market outcomes [LB].

2. The second branch of the project examines instead the effects of discovery of decade-long PFAS contamination: 

   • the first paper [D1] examines changes in the social composition of the affected community, contrasting the possibly negative effects on school enrollment, demographics, population flows, taxable income, public expenditure and housing prices, with the positive effects recorded on student performance of previously contaminated students.

   • the second paper [D2] zooms in on individual behavior in the contaminated area, including tap water consumption, environmental concerns, health-related choices and political participation.

Identification

• Identification of the effects of PFAS exposure (paragraph 1 above) relies mainly on the sharp discontinuity in PFAS contamination experienced by residents across the border of the Red Zone, which roughly coincides with the administrative outer border of the 27 contiguous municipalities served by the contaminated water supplier. This setup is exploited as a Geographic Quasi Experiment (GQE, local randomization with a geographical threshold), by comparing outcomes close to the border of the Red zone, before pollution discovery, for the relevant statistical unit (newborns, students, workers, residents of each municipality). In the area considered, municipalities – the smallest administrative division in Italy – can be thought as interconnected neighborhoods part of a rural-urban continuum. An optimally rotated 10-sector angular grid, and a 5-km buffer from the border, minimize pre-exposure differences in key census variables between treatment and control group. Within-sector-buffer comparisons are further shown to be balanced along several dimensions. Depending on the specific outcome and its measurement, spillover effects across the border can lead to downward bias in GQE estimates. This problem is less severe when employing "donut-hole" difference-in-differences analyses, which in some applications complement the GQE analysis to delve into mechanisms.

• Identification of the effects of PFAS discovery (paragraph 2 above) rely instead on standard difference-in-differences analysis.

Project design

Diagram 1 illustrates the building blocks of the project. 

• All GQE-based papers (HC, H1, H2, H3, and LB) rely on municipal-level estimates of PFAS levels and on the optimal sector-buffer-rotation configuration of the GQE spatial grid described above.

• Tests show that, while units within the Red zone were discontinuously exposed to high levels of PFAS, demographics, the parental background of students enrolled in the exposed area, housing values, household characteristics, etc. were indistinguishable in nearby municipalities before contamination discovery (but after arrival of contamination). 

• Considering years before and after 2013, part of the data used to exclude indirect effects and endogenous responses in GQE-based papers (population, housing prices, taxable income, municipal expenses) is used to study whether contamination discovery resulted in compositional change in the contaminated area, changes in housing prices, municipal revenues and expenditure (D1).

• Virtually all papers on the effects of PFAS exposure are further supported by Multiscopo data. These data, accessed in restricted form in a secure data lab, report characteristics, behavior, attitudes and preferences of sampled households, together with municipal identifiers. The same data are used to document whether contamination discovery led to behavioral changes in tap water consumption, health-related habits, etc. (D2).

Papers  (note: titles are preliminary, and some papers might eventually be combined)

[HC] PFAS Exposure and Cognitive Development: Evidence from an Italian Environmental Incident  

Status / latest update: Collegio Carlo Alberto Working paper, SSRN working paper, R&R at Economic Journal

Relevance for the project: 

• this is the main paper in the project. It lays foundations for all other papers and establishes the optimal GQE strategy

• the latest revision of the paper

  • focuses on mechanisms, carefully documenting broad absence of indirect effects and endogenous responses in the 2000-2012 period, which is relevant for most other papers

  • is a direct complement to the evidence presented in D1

  • delves into the nature of estimated effects, complementing the health evidence provided in H2

Presentations:

• 2025/05 – IZA Workshop on Climate and Environmental Economics: Applied and Behavioral Perspectives, Bonn

• 2025/04 – Gran Sasso Science Institute Environment and Climate Change Research Track Internal Seminar, L’Aquila

• 2025/02 – Bologna Health Economics and Public Policy Evaluation Seminar, Bologna

• 2025/01 – Joint Research Center of the European Commission, Ispra

• 2024/06 – International Workshop on Applied Economics of Education, Catanzaro

• 2024/04 – SOFI brown bag, Stockholm

• 2024/03 – ESOMAS internal seminar, Turin

• 2024/03 – Collegio Carlo Alberto internal seminar, Turin

[H1] The Effect of Long-run PFAS Exposure on Mortality

Status / latest update: Collegio Carlo Alberto Working Paper, SSRN Working Paper, under revision

Relevance for the project: 

• documents balance between treated and control units in several dimensions in the decades before 2000, including before contamination arrival (1951-1981)

• provides historical evidence on which areas saw increases in mortality after exposure, when this happened, with what magnitude, and which demographics were most affected. This contextual information is useful for HC and especially H1 and LB

Presentations:

• 2025/06 – Workshop on Applied Environmental and Health Economics – Local Externalities, Inequalities and Policies, Rome

[D1] Clearing the Water: Cognitive Recovery and Residential Sorting after PFAS Contamination Discovery

Status / latest update: 

• academic performance for exposed students sharply improves over grade, broadly tracking expected decay of PFAS levels in blood

• at the same time preliminary analyses show negative compositional change in school enrollment after 2017, and worsening demographic composition from 2019

• access to restricted individual-level administrative records on inter-municipal moves will allow to

  • measure and characterize compositional change in exposed municipalities

  • test whether municipalities near the exposed area were also negatively affected by the discovery of PFAS contamination, and hence to define the boundaries of news-induced avoidance behavior

Relevance for the project: 

• evidence on how academic performance changes post-discovery for exposed students directly complements HC, evaluating the persistence of the human capital effects there estimated

• since behavioral changes cannot be identified in the presence of compositional change, characterizing its timing and geographical extension is essential for D2

[H2] PFAS Exposure and Children's Health

Status / latest update: 

• the share of students certified by a team of doctors with moderate to serious disability levels is balanced across the Red Zone border in the post-2000 period, when I instead observe the highest increases in mortality in the adult population. This suggests that while PFAS exposure appears to affect cognitive performance, it does not lead to disability 

• access to restricted individual-level administrative records on birth outcomes will allow to inspect different margins (birthweight, gestation age, etc.)

Relevance for the project: 

• complements evidence provided in HC and LB, allowing to establish potential nexuses between birth-related health, cognitive performance, and earnings

[D2] Behavioral Responses after Discovering Twenty Years of PFAS Contamination

Status / latest update: preliminary analyses performed at Laboratorio Adele show, among other things, sharp drops in tap water consumption in the contaminated area after 2013 

Relevance for the project: 

• the main data source, the Multiscopo surveys, provide ancillary descriptive information for all papers in the project

• complements the analysis performed in D1

[LB] Labor market effects of PFAS Exposure

Status / latest update: preliminary analysis performed on aggregate data does not reveal lower taxable income, for recent cohorts, in the contaminated area.

Relevance for the project: 

• provides historical evidence about the timing and magnitude of the effect of PFAS exposure on the working-age population

• since the data includes information about where adults are born, reside and work, this paper provides useful information about the level of attenuation bias induced by cross-border spillover effects, relevant for all GQE-based papers (HC, H1, H2, H3)

[H3] PFAS Exposure and Fertility

Status: 

• preliminary analyses do not show lower fertility, for recent cohorts, in the contaminated area

• access to restricted administrative records, with coverage from the 80s, will allow to measure effects using appropriate fertility measures

Relevance for the project: 

• complements evidence provided in H1, considering reproductive health, which is both a strong concern in the PFAS medical literature and an important economic outcome