RESEARCH

Human activities and modern industry have released large quantities of heavy metals and approximately 100,000 synthetic organic compounds to the global environment. When present in the human body, these environmental toxicants have been linked to many negative health effects, such as the global pandemic of neurocognitive deficits in children, increased risks of cardiovascular disease, and a rapid rise in immune disorders. However, the links between human activities that release environmental toxicants and their adverse impacts on health have not been well established because chemical cycling through the physical environment and food webs is not well understood. Disciplinary boundaries between environmental chemistry, ecology and epidemiology have made it challenging to forecast how changes in emissions of toxicants will affect human and ecological health. This is particularly true for exposures from drinking water and seafood, which are mediated by aquatic environments. The result of this dearth of knowledge has been weak regulations and limited protection of public health. Our work aims to address this gap through interdisciplinary investigations of the exposure pathway for toxicants.

FIELD/LABORATORY RESEARCH

BIOGEOCHEMICAL MODELS

RISK ASSESSMENT

Our field and lab research focuses on understanding relationships between environmental properties (e.g., DOC, temperature, productivity) and chemical speciation/bioavailabilty of trace metals and organic compounds. We measure reaction rates and concentrations in environmental samples that can be used to parameterize and evaluate our modeling simulations. We use a variety of instruments in our lab including HPLC-MS/MS, ICP-MS, and MC-ICP-MS.

We use environmental models to investigate the broader spatial and temporal implications of relationships measured in the field and to synthesize multi-disciplinary research. Our models vary in complexity from statistical tools and relatively simple geochemical box models to global 3-D simulations of atmospheric and ocean circulation and ecology. We also model bioaccumulation of contaminants in aquatic food webs and collaborate with fisheries scientists to link our models to aquatic life.

 

Code for our models can be downloaded from GitHub

We use food-frequency questionnaires (FFQs) and probabilistic exposure simulations integrated with toxicokinetic (TK) models to estimate human exposures to contaminants. We also measure human biomarkers of exposure (hair, blood). We work closely with environmental epidemiologists looking at dose-response relationships to quantify present risks and link this information with environmental models to help anticipate public health impacts of climate change and regulations.

- Ongoing Research -

 

We are conducting diverse ongoing research projects that address the broad themes described briefly below or click for a

compilation of recent (2016-present) thematic publications:

PFAS Exposure | Mercury Biogeochemistry | Arctic/Subarctic | Marine Pollution | Risk Assessment

Project Descriptions

| PFAS Exposure |

Background:

Per- and polyfluoroalkyl substances (PFAS) are highly fluorinated anthropogenic chemicals that are widely used by industry and in diverse consumer products.  Exposure to PFAS has been associated with many adverse impacts on human health including immunotoxicity, metabolic disruption, endocrine effects, and certain cancers.

 

Approach:

Our research aims to better understand the diverse human exposure sources for PFAS, which is essential for developing effective risk mitigation strategies for these chemicals. Our work combines measurements of targeted PFAS, extractable organofluorine (EOF), and non-targeted analysis (NTA) to close the mass budget for PFAS in environmental samples and biological tissues. We use diverse statistical and environmental modeling techniques to better understand sources contributing to the burden of PFAS measured in environmental samples and environmental transport and transformations.

 

Ongoing Project Objectives:

  • Assess atmospheric source-receptor relationships for PFAS in the Northeastern and Midwestern US using the GEOS-Chem atmospheric chemistry transport model (Colin Thackray, Jennifer Sun, Lara Schultes)
  • Characterize precursor concentrations and transformations in groundwater at an AFFF contaminated site on Cape Cod, MA by measuring sorption, biodegradation, and numerical modeling constrained by observations (Bridger Ruyle, Lara Schultes)
  • Develop a statistical modeling approach to identify private wells that are vulnerable to PFAS contamination and factors affecting PFAS in public water supplies (Jennifer Sun, Jahred Liddie)
  • Better understand the agronomic PFAS exposure pathways in the state of Maine (Heidi Pickard, Jordan Daigle)
  • Identify sources of PFAS in indoor dust and total organofluorine concentrations in products (Heidi Pickard, Anna Young and Joe Allen, HSPH)
  • Identify temporal changes in PFAS concentrations in humans and biota in response to shifts in production and regulation (Heidi Pickard)

 

Collaborators:

Air Modeling: Michigan EGLE, Rainer Lohmann (URI)

Cape Cod Watersheds: Denis LeBlanc and Andrea Tokranov (USGS)

Biodegradation: Michelle Lorah and Denise Akob (USGS)

Drinking Water Modeling: New Hampshire DES

Agronomic Exposure Pathway: Maine DEP

Human Exposure Trends and Toxicokinetics: Philippe Grandjean (Harvard)

 

Funding: NIEHS, SERDP

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| Mercury Biogeochemistry |

Background:

Methylmercury is a potent neurotoxicant and exposures have also been linked to adverse impacts on cardiovascular health. Human activities such as mining and fossil fuel combustion have greatly enriched environmental concentrations of methylmercury and this is being exacerbated in some regions by anthropogenic climate changes.

 

Approach:

We combine lab measurements of speciated mercury at trace levels and mercury isotopes in environmental and biological samples with many modeling tools ranging from simple box-models and food web accumulation simulations to coupled 3-D earth systems models.  Our goal is to understand the impacts of human perturbations, both directly through mercury emissions and indirectly through ecosystem change on exposure.

 

Ongoing Project Objectives:

 

Collaborators:

Terrestrial Hg dynamics: Charley Driscoll (Syracuse), David Krabbenhoft (USGS)

Permafrost regions: Kevin Schaefer (CU Boulder) and Sue Natalie (Woodwell Climate)

Coal-fired power plant risks: Charley Driscoll (Syracuse) and Kathy Fallon Lambert (HSPH)

Historical emissions: David Streets (Argonne National Laboratory)

Human microbiome: Chris Golden and Curtis Huttenhower (HSPH)

 

Funding: U.S. Energy Foundation, Harvard NIEHS Program

 

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| Arctic/Subarctic |

Background:

Global pollutants are accumulating in sensitive Arctic and Subarctic ecosystems. Much of our research aims to better understand the health risks associated of these pollutants but they also pose risks to traditional cultures in many regions. The cultural costs have been acknowledged but not quantified in past work and raise environmental justice concerns about pollution.

 

Approach:

Through a case study of the Faroe Islands as a traditional whaling society in the Subarctic, we are examining the health and cultural costs of global ocean pollution.

 

Collaborators:

Policy and human well-being: Russell Fielding (Coastal Carolina U.) and Yoshi Ota (UW)

Faroe Islands: Bjarni Mikkelsen, Pal Weihe, Maria Skaalum Petersen

 

Funding: Ocean Nexus/Nippon Foundation

 

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| Marine Pollution |

Background:

The ocean is the terminal sink for many anthropogenic pollutants. Some pollutants biomagnify in food webs and pose risks to ecosystem health and fish consumers.

 

Approach:

We are broadly interested in understanding the effects of climate-driven changes in the ocean on the distribution of human pollutants in the physical environment and food-web dynamics. In addition to studying the PFAS and mercury in marine ecosystems (see above), we are studying the large-scale behavior of neutral persistent organic pollutants (POPs) like polychlorinated biphenyls (PCBs), that provide useful benchmarks of POP behavior. We have focused our efforts on developing global 3-D models of oceanic and atmospheric cycling and studies of food web accumulation.

 

Recently completed:

Collaborators:

Field measurements: Rainer Lohmann, URI

Food web: John Logan, MA MFW

 

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| Risk Assessment |

Background:

We are engaged in research to assess and mitigate risks associated with anthropogenic pollutants.

 

Approach:

Our approach includes collecting new data on environmental concentrations of pollutants as well as biomarkers of exposures in humans. We use geospatial modeling tools to identify vulnerable regions based on pollutant source distributions and data science methods to help identify factors contributing to vulnerability.

 

Ongoing Project Objectives:

  • Characterize community health risks associated with heavy-metal exposures from rapid expansion of coal-fired power plants in South India. (Prentiss Balcom).
  • Develop a national scale model for heavy metal mixtures in drinking water and evaluate their contribution to exposures of the US general population (Mona Dai).

 

Collaborators:

Nurses health study: Francine Laden (HSPH)

South India community exposures: Asif Qureshi (IIT Hyderbaad)

 

Funding: NIEHS, HGI

 

 

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Sunderland Lab

Group Administrator: Brenda Mathieu

Address: 29 Oxford Street, Cambridge MA 02138

E-mail:  bmathieu [at] seas.harvard.edu

Phone: +1 (617) 496-5745

Fax: +1 (617) 495-4551