Mitigation of building-related polychlorinated biphenyls in indoor air of a school

Environmental Health

Research

Matthew A Fragala¹  Joseph G Allen¹  Kevin M Coghlan¹  David L MacIntosh¹  John F McCarthy¹  Taeko Minegishi¹  James H Stewart¹ 

[1] Environmental Health & Engineering, Inc, 117 Fourth Avenue, 02494-2705, Needham, MA, USA;

关键词: Remediation;    Abatement;    Flux;    Risk management;   

DOI  :  10.1186/1476-069X-11-24

 received in 2012-02-05, accepted in 2012-04-10,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundSealants and other building materials sold in the U.S. from 1958 - 1971 were commonly manufactured with polychlorinated biphenyls (PCBs) at percent quantities by weight. Volatilization of PCBs from construction materials has been reported to produce PCB levels in indoor air that exceed health protective guideline values. The discovery of PCBs in indoor air of schools can produce numerous complications including disruption of normal operations and potential risks to health. Understanding the dynamics of building-related PCBs in indoor air is needed to identify effective strategies for managing potential exposures and risks. This paper reports on the efficacy of selected engineering controls implemented to mitigate concentrations of PCBs in indoor air.MethodsThree interventions (ventilation, contact encapsulation, and physical barriers) were evaluated in an elementary school with PCB-containing caulk and elevated PCB concentrations in indoor air. Fluorescent light ballasts did not contain PCBs. Following implementation of the final intervention, measurements obtained over 14 months were used to assess the efficacy of the mitigation methods over time as well as temporal variability of PCBs in indoor air.ResultsControlling for air exchange rates and temperature, the interventions produced statistically significant (p < 0.05) reductions in concentrations of PCBs in indoor air of the school. The mitigation measures remained effective over the course of the entire follow-up period. After all interventions were implemented, PCB levels in indoor air were associated with indoor temperature. In a "broken-stick" regression model with a node at 20°C, temperature explained 79% of the variability of indoor PCB concentrations over time (p < 0.001).ConclusionsIncreasing outdoor air ventilation, encapsulating caulk, and constructing a physical barrier over the encapsulated material were shown to be effective at reducing exposure concentrations of PCBs in indoor air of a school and also preventing direct contact with PCB caulk. In-place management methods such as these avoid the disruption and higher costs of demolition, disposal and reconstruction required when PCB-containing building materials are removed from a school. Because of the influence of temperature on indoor air PCB levels, risk assessment results based on short-term measurements, e.g., a single day or season, may be erroneous and could lead to sub-optimal allocation of resources.

【 授权许可】

CC BY   
© MacIntosh et al; licensee BioMed Central Ltd. 2012