Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA)-power plant studies: assessment of cellular responses

Abstract

The Toxicological Evaluation of Realistic Emission Source Aerosols (TERESA) project assessed primary and secondary particulate by simulating the chemical reactions that a plume from a source might undergo during atmospheric transport and added other atmospheric constituents that might interact with it. Three coal-fired power plants with different coal and different emission controls were used. Male Sprague-Dawley rats were exposed for 6 h to either filtered air or aged aerosol from the power plant. Four exposure scenarios were studied: primary particles (P); primary + secondary (oxidized) particles (PO); primary + secondary (oxidized) particles + SOA (POS); and primary + secondary (oxidized) particles neutralized + SOA (PONS). Exposure concentrations varied by scenario to a maximum concentration of 257.1 ± 10.0 μg/m³. Twenty-four hours after exposure, pulmonary cellular responses were assessed by bronchoalveolar lavage (BAL), complete blood count (CBC), and histopathology. Exposure to the PONS and POS scenarios produced significant increases in BAL total cells and macrophage numbers at two plants. The PONS and P scenarios were associated with significant increases in BAL neutrophils and the presence of occasional neutrophils and increased macrophages in the airways and alveoli of exposed animals. Univariate analyses and random forest analyses showed that increases in total cell count and macrophage cell count were significantly associated with neutralized sulfate and several correlated measurements. Increases in neutrophils in BAL were associated with zinc. There were no significant differences in CBC parameters or blood vessel wall thickness by histopathology. The association between neutrophils increases and zinc raises the possibility that metals play a role in this response.

Keywords::

• Bronchoalveolar lavage
• inflammation
• histology
• inhaled particles
• power plant emissions
• aerosol sources
• pollution sources

Acknowledgments

The authors thank power plant personnel, the local universities, veterinary clinics, and suppliers who made an extraordinary effort to make a logistically very complex project possible.

Declaration of interest

This project was supported by the Electric Power Research Institute (Contract EP-P10983/C5530/56546), the U.S. Environmental Protection Agency Center, for Particle Health Effects at the Harvard School of Public Health (grant R827353), and the Harvard NIEHS Center for Environmental Health (grant ES00002). This work was also prepared with the support of the U.S. Department of Energy (DOE) under award DE-FC26-03NT41902, and a grant from the State of Wisconsin. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the authors, and do not necessarily reflect the views of the U.S. EPA or the DOE.