Theme: 09. Vapor Intrusion

Topic Area: 9d. Vapor Intrusion Risk Assessment and Site Management

Formatted Title:

Risk Communication for Mitigation Actions and Human Health Protection in Contaminated Residential Areas with Tension Increase

Background/Objectives:

Risk communication is part of the management of a contaminated area and is prescribed in Brazil and in the State of São Paulo by Resolution Conama 420/2009 and by State Law 13.577/2009, respectively. It is a process involving representatives of all social groups and requires stakeholders to actively participate in a constructive way. However, there are no specific guidelines to procedures and strategies on how risk communication should be conducted. Therefore, it is in this context that this article is elaborated, with the presentation of one case study where communication and joint ideas for development of tools, between all stakeholders involved, were considered a key component for the implementation of risk mitigation actions, especially in moments when the pressure from residents and regulatory agencies raised.

Approach/Activities:

The case study is related to residential areas contaminated with chlorinated solvent products, with occurrences of vapor intrusion, where the vapors migrated from the tetrachloroethene plume in groundwater whose source came from the upstream industries that had used this substance in their process. As the concentrations in indoor air were above standards, mitigation actions were immediately required to protect resident’s health. A Communication Strategy was conceived, by mapping all the stakeholders – environmental agency, health surveillance, municipality, the responsible party for the environmental liabilities, residents, consultants, and subcontractors – and establishing information channels and a risk communication matrix. In summary, risk communication was performed using several communication channels and approaches: a) individual and small groups meetings, with the participation of governmental and non-governmental agencies; b) preparation and distribution of informative notes; c) toxicologist technical support; d) providing a contact number or an e-mail for residents to contact at any time with their questions and schedule work; e) the technical team in the field answered resident’s technical questions with accessible language; and f) above all transparency, constant feedbacks and empathy.

Results/Lessons Learned:

The risk communication process promoted in this case study the cooperation between the stakeholders involved during the implementation of the vapor intrusion investigation and the mitigation of potential risks, with applied engineering actions and subslab depressurization system, which were supported by the environmental agencies.

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Manuela Galvão