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.

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.

STEEP: SOURCES, TRANSPORT, EXPOSURE & EFFECTS OF PFAS

Funding: URI/Harvard Superfund Research Center funded by the National Institute of Environmental Health Sciences (NIEHS) (2017-2022)

Project 1: Exposure Assessment and Chemometrics of Poly- and Perfluoroalkyl substances (PFAS)

Description: The aims of this work are to: 1) Develop novel statistical and modeling tools for source attribution of PFAS; 2) Better understand the vulnerability of drinking water suplies and seafood resources next to contaminated sites by studying biogeochemical factors that affect PFAS transport and bioaccumulation; 3) Better characterize PFAS exposure pathways and lifetimes for diverse human populations.

People: Lara Schultes, Heidi Pickard, Jennifer Sun, Bridger Ruyle, Colin Thackray

Collaborators: Philippe Grandjean (Harvard), Rainer Lohmann (URI), Angela Slitt (URI).

MEMCARE: Metals and Metal Mixtures: Cognitive Aging, Remediation and Exposure Sources

Funding: Harvard Superfund Research Center funded by the National Institute of Environmental Health Sciences (NIEHS) (2020-2025)

Project 3: Metal mixtures in US drinking water

Description: The aims of this work are to identify geospatial clustering of metal mixtures in US groundwater and municipal drinking water supplies that lead to adverse human exposures and their association with known point sources.

People: Mona Dai, Jennifer Sun, Jonas LaPier

Collaborators: Cindy Hu (Mathematica), Francine Laden (Harvard), David Andrews (EWG)

PFAS PrecursOr Transport and Transformations in Groundwater

Funding: DOD/SERDP (2019-2022)

Description: This project aims to better understand factors affecting the mobility and accumulation of PFAS in groundwater and includes sorption experiments, biodegradation experiments, and reactive-transport modeling.

People: Bridger Ruyle, Shelley McCann, Lara Schultes

Collaborators: Chad Vecitis (Nth Cycle), Rainer Lohmann (URI)

PFAS EXPOSURE and health effects FROM CONTAMINATED DRINKING WATER

Funding: ATSDR/CDC (2020-2025)

Description: We are participating in community study looking at the health impacts of PFAS exposure from drinking water at contaminated sites in MA (Hyannis and Ayer) led by the Silent Spring Institute. Our role is to measure total extractable organofluorine in drinking water and human serum and to develop toxicokinetic models for PFAS exposure.

People: Elsie Sunderland

Collaborators: Laurel Schaider (Silent Spring), Clifton Dassuncao (ERG)

Environmental tipping points of cultural identity extinction in integrated human-ecological systems represented by small fishing nations

Funding: Nippon Foundation (2020-2022)

Description: This pilot project will examine how the occurrence of global environmental contaminants in traditional foods in the Faroe Islands has affected risk perception and cultural identity.

People: Charlotte Wagner

Collaborators: Yoshi Ota (UW), Russell Fielding

Health impacts of coal-based energy generation in india

Funding: Harvard Global Institute (2017-2020)

Description: This project aims to better understand the cumulative health impacts associated with toxic pollutant emissions from coal-fired power plants, including both traditional air pollutants and a suite of heavy metals.

People: Prentiss Balcom, Aaron Specht (HSPH)

Collaborators: Asif Qureshi (IIT, India)

ground up estimates of atmospheric methane from aquatic ecosystems

Funding: NASA and Harvard Climate Change Solutions Fund (2017-2020)

Description: We are developing ground up global estimates for atmospheric methane releases from hydroelectric reservoirs and coastal ecosystems.

People: Colin Thackray and Kyle Delwiche (now at Stanford)

Collaborators: Daniel J. Jacob

Mercury cycling in terrestrial and permafrost regions

Description: Terrestrial ecosystems account for the largest global reservoir of mercury but processes controlling cycling and accumulation are poorly understood.  We are collaborating with the USGS to interpret the measured distribution of soil mercury across the contiguous United States using the Global Terrestrial Mercury Model (GTMM). We are also extending the model to develop an improved representation of mercury accumulation in frozen soils.  Collaboration with the WHRC is alllowing the collection of new data on mercury fluxes in permafrost soils.

People: Ben Geyman, Colin Thackray, Max Enrico, Prentiss Balcom, Scott Zolkos

Collaborators: Charley Driscoll (Syracuse), Dave Krabbenhoft (USGS), Sue Natali (WHRC), Kevin Schaefer (UCB)