RESEARCH

Our research investigates how biogeochemical processes affect the fate, transport and food-web bioaccumulation of trace metals and organic chemicals in aquatic ecosystems. Our applied goal is to characterize how changes in climate and emissions affect human and ecological health, and the potential impacts of regulatory actions. Our research integrates understanding of the physical/chemical properties of contaminants with the biogeochemistry of natural ecosystems and human/ecological exposure pathways.

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 are ramping up our in-house analytical capacity to measure a suite of contaminants using HPLC-MS/MS and 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 relatively simple geochemical box models to advanced 3-D simulations of atmospheric (GEOS-Chem) and ocean circulation (MITgcm, FVCOM) driven by assimilated meteorological data. We are also developing models for bioaccumulation of contaminants in marine food webs.

We use food-frequency questionnaires (FFQs) and probabilistic exposure simulations integrated with pharmacokinetic (PK) 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.

- OVERVIEW OF CURRENT PROJECTS -

Biogeochemical Modeling

Lab/Field Based Projects

Risk Assessment

Background:

 

Our work is developing and evaluating global simulations for compounds of interest in the oceans within the MITgcm with ecology (Darwin model). We are using these simulations to better understand the relationship between global production of these chemicals and accumulation in food-web and ultimately human exposure. We use the GEOS-Chem model to simulate atmospheric inputs to aquatic and terrestrial systems.

 

 

 

 

Ongoing Projects and People:

 

  • Global budgets for Hg, PCBs and PFASs in the oceans and influence of climate (Charlotte Wagner, Colin Thackray)
  • Cycling of  persistent organic pollutants in the ocean (Charlotte Wagner, Colin Thackray)
  • Global methane releases from hydroelectric reservoirs (Bram Maasakkers, Kyle Delwiche)
  • Global model for MeHg bioaccumulation in fisheries (Colin Thackray, Miling Li, Amina Schartup)

 

Collaborators: Rainer Lohmann (URI), Daniel Jacob (Harvard)

 

Support:  UBC Nereus Project, Harvard Climate Change Solutions Fund , Nunatsiavut Government

 

Background:

We are interested in the global biogeochemical cycles of environmental contaminants (mainly Hg, Se, PFASs) and the impacts of human activities on accumulation in marine ecosystems.  Hg has been released in large quantities from mining and fuel combustion and continues to cycle in the environment over long-timescales.  Some of the Hg naturally present in aquatic ecosystems is converted into methylmercury (MeHg), the only form to bioaccumulate in food webs.  A main focus of our research program is understanding how human activities have contributed to Hg enrichment in marine systems. A related question is how ecosystem characteristics such as DOC composition, organic enrichment, phytoplankton community composition affect MeHg production, bioavailability, and accumulation in marine food webs.

Ongoing Projects and People:

 

  • Carbon respiration and production of methylmercury and methane in flooded soils (Prentiss Balcom, Linjun Yao)

 

  • Geochemical factors influencing transport and accumulation of PFASs in drinking water and fish (Andrea Weber, Cindy Hu, Clifton Dassuncao, Heidi Pickard, Bridger Ruyle)

 

  • Environmental factors driving methylation and demethylation of Hg species in oxic marine water (Amina Schartup)
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  • PFASs and Hg speciation in seawater and plankton from the Northeast Atlantic Ocean (Charlotte Wagner, Xianming Zhang, Ben Geyman)
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  • Temporal trends and bioaccumulation of contaminants (PFASs, PCBs, MeHg) in pilot whale food webs from the North Atlantic (Clifton Dassuncao, Miling Li)
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  • Pharmacokinetics of  contaminant uptake and elimination in marine mammals (Clifton Dassuncao)

 

Collaborators: Dave Krabbenhoft (USGS), Bjarni Mikkelsen & Maria Dam (Faroe Islands)

 

Support: Nunatsiavut Government, NIEHS, STAR Family

 

Background:

 

We have a number of projects that are characterizing contaminant exposures using dietary surveys and probabilistic exposure simulations linked to PBPK models. We work closely with environmental epidemiologists in the School of Public Health  to understand the public health impacts of changes in environmental releases of toxicants.

 

We are particularly interested in PFASs and MeHg because of their strong association with suppressed immune function and neurocognitive development, respectively, in children. We are collaborating with researchers in the U.S., Faroe Islands, and Labrador to better understand how changes in ocean bioegochemistry and trends in chemical production are affecting children's health.

Projects and People:

 

  • Fingerprinting sources and temporal trends in PFAS exposure for different populations (Cindy Hu, Clifton Dassuncao)

 

  • Airborne meningitis in African dust (Rebecca Stern, Caroline Buckee)
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  • Heavy metals and PFASs in drinking water from the Nurses Health Study cohort (Cindy Hu)
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  • Dietary modification of MeHg uptake from food (Marie Perkins)

 

 

Collaborators: Philippe Grandjean (Harvard), Francine Laden (Harvard), Nick Fisher (Stony Brook)

 

Support: NIH-NSF Oceans and Human Health Program, U.S. EPA, Harvard NIEHS Center, Gelfond Fund

 

- Research Sponsors -

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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