VPP – Veneto PFAS Project

page updated: 2025/05/07

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 evidence proving 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 health, cognitive performance, and labor market outcomes. On top of that, the project examines how local communities respond to the discovery of PFAS contamination.

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 thirty municipalities located in the Veneto region (Italy) were served PFAS-contaminated 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 leading 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 specific 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 academic performance  [HC] and health [H2], adult mortality [H1], fertility [H3], and labor market outcomes [LB].

2. The second branch of the project considers instead whether and to what extent discovery of twenty years of PFAS contamination affected

   • the social composition of the affected community, examining demographics (including population flows), taxable income, public expenditure and housing prices, and also considering the possibly more malleable social composition of the students enrolled in schools located in the Red Zone [D1]

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

Identification

• Identification of the effects of PFAS exposure (paragraph 1 above) relies on the sharp discontinuity in PFAS contamination experienced by the residents of municipalities located across the border of the Red Zone. This setup is exploited as a Geographic Quasi Experiment (GQE, local randomization with a geographical threshold), comparing outcomes close to the border of the Red zone, before pollution discovery, for the relevant statistical unit (newborns, students, workers, municipalities). In the area considered, municipalities, the smallest administrative division in Italy, can be thought as neighborhoods of larger metropolitan areas. People, whose individual PFAS contamination levels are unknown, could easily move across municipal borders. GQE estimates therefore generally identify lower bounds of ITT effects.

• Identification of the effects of PFAS discovery (paragraph 2 above) rely instead on more 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 optimal "GQE grids". The latter are derived combining GIS work with extensive statistical testing on, depending on the specific outcome, (INVALSI) data on students' parental background, (ISTAT) population demographics, (Agenzia delle Entrate) housing prices and taxed municipal income, municipal balance sheets, (ISTAT) census and historical census data, and (INEMAR) emissions data. 

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

• Considering years before and after 2013, part of the data used to support 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 and public expenditure (D1).

• Virtually all papers on the effects of PFAS exposure are further supported by Multiscopo data. This data, accessed in restricted form in a secure ISTAT data lab, reports characteristics, behavior, attitudes and preferences of sampled households, together with municipal identifiers. The same data is 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: 

• main paper in the project, lays foundations for all other papers

• establishes optimal GQE strategy, cross-validates it with a continuous DiD strategy, document/quantifies spillover effects across the Red Zone border

• analyses in appendix will eventually be moved to D1. D2 will provide additional supporting evidence

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: preliminary analysis shows increased mortality in the contaminated area

Relevance for the project: 

• provides historical evidence about the timing and magnitude of the effect of PFAS exposure on the adult population

• this evidence, together with robustness checks performed on historical censuses, is relevant for LB and to understand mechanisms in HC 

Presentations:

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

[D1] Is there a Price to Underground Water Contamination? Housing Prices and Social Composition after PFAS Discovery

Status / latest update: preliminary analyses show some evidence of compositional change after 2017, more evident among families with young children, and small to insignificant effects in housing prices

Relevance for the project: 

• identifying when compositional place takes place is relevant for HC (for the difference-in-differences analysis) and D2 (behavioral changes cannot be identified in the presence of compositional change)

[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 adult population

• this evidence, together with robustness checks performed in the pre-exposure period (70-85), is relevant for HC and H1

• since the data includes information about where adults (including mothers) are born, reside and work, this paper provides useful information about the level of attenuation bias in all GQE-based papers (HC, H1, H2, H3)

[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: 

• provides ancillary descriptive information for other project papers

• provides supporting evidence for HC (difference-in-differences analysis) and D1

[H2] PFAS Exposure and Children's Health

Status / latest update: 

• preliminary analyses show higher (moderate to serious certified) disability levels in the contaminated area. 

• analysis on birth outcomes is contingent on access to CEDAP data 

Relevance for the project: 

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

[H3] PFAS Exposure and Fertility

Status: 

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

• more suitable data, with coverage from the 80s, will allow to use more 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 a relevant economic outcome