We address public health research questions through molecular-level analyses of chemical contaminants and biomarkers. A primary component of this research is the development of advanced analytical methods. Often these compounds are analyzed in complex sample matrices; therefore, most methods in our laboratory utilize chromatography and mass spectrometry for chemical identification and quantification.
Non-Targeted Contaminant Discovery
There is concern that unrecognized or novel contaminants are either contributing to current health impacts or may pose an elevated risk in the future. Using non-targeted mass spectrometry, we developed an approach for the detection of a broad range of organic compounds in fish oil and marine mammal blubber samples. This approach provides a comprehensive contaminant profile that can be used to investigate differences among sample groups, identify related but unknown compounds such as precursors or degradation products of known contaminants, and suggest new chemicals for further risk assessment. Processing the non-targeted data sets requires the development of custom software. We are continuously working to further the development of non-targeted analytical approaches and their applications to environmental monitoring, food safety, and exposure assessment.
- Evaluation of contaminant removal in decentralized water reuse systems.
- Identify unexpected organic contaminants following advanced oxidation water treatment processes.
- Enhanced cataloging of bioaccumulative chemicals in stranded marine mammals to assess health impacts.
- Nontargeted analysis of sediment and water in San Francisco Bay.
Environmental Fate and Human Exposure to Contaminants
Quantitative mass spectrometry methods are developed to study the behavior of specific environmental contaminants and their associated biomarkers. Our laboratory developed targeted GC/MS and LC/MS/MS analytical methods for tobacco smoke components and related biomarkers (discussed below; e.g., nicotine, tobacco specific nitrosamines, and cotinine), pesticides and related biomarkers, persistent organic pollutants (e.g., PCBs, organochlorine pesticides, and flame retardants), and other contaminants of known and emerging concern.
- Examining the efficiency of contaminated soil/sediment remediation through analysis of PAHs.
- Pesticide exposure among agricultural communities.
Third-Hand Tobacco Smoke Exposure
Tobacco smoke can be a major contributor to indoor air pollution. When dust and surfaces remain contaminated long after active smoking has ceased, it is referred to as "thirdhand" smoke. We investigate human exposure to thirdhand smoke under various indoor settings such as homes, cars, and commercial businesses, and compare thirdhand smoke profiles to smoking behavior.
- Persistent thirdhand smoke toxicants in indoor environments.
- Thirdhand smoke pollution and remediation in low-income housing.
- Contribution of thirdhand smoke to overall tobacco smoke exposure in a pediatric population.
- Effects of thirdhand smoke exposure on the microbiome of children.
Environmental Tobacco Product Waste
Discarded cigarette butts are among the most prevalent litter found at ocean beaches and in inland waterways. However, their impact on the environment has not been evaluated. Are they just an unsightly litter problem? Cigarette tobacco and cigarette smoke contain numerous toxic chemicals, and cigarette filters are made of non-biodegradable plastic that trap cigarette smoke particulates and less volatile chemicals. Therefore, it is reasonable to expect that cigarette butts contain harmful chemicals in the filters along with unburned tobacco.Documentary on the potential environmental impact of discarded cigarette butts.
- Identification of tobacco product waste contaminants by non-targeted analysis.
- Assessing the toxicity of tobacco product waste.