Superfund Research Program

Biogeochemistry Core

Project Leader: Alexander F. van Geen
Co-Investigators: Steven N. Chillrud, Beizhan Yan (Lamont Doherty Earth Observatory of Columbia University)
Grant Number: P42ES010349
Funding Period: 2000-2021

Project-Specific Links

Final Progress Reports

Year:   2020  2016  2010  2005 

The Biogeochemical Analytical Core laboratory is housed at Lamont-Doherty Earth Observatory. It provides sample preparation and analyses to six projects of the Columbia SRP. Analyses have been carried out by high-resolution inductively coupled plasma mass spectrometry for up to 33 elements for water, soil, sediment, leachate, and plant material (HR ICP-MS). The researchers have also recently acquired a polarized energy dispersive X-ray fluorescence (XRF) spectrometer. This bench-top XRF has an autosampler and the ability to flush the analysis chamber with helium, thus allowing routine analysis from Na to U. In addition, subcontracts with two outside collaborators have boosted the Core’s capabilities in two new areas to include extended X-ray absorption spectroscopy (XAS) of aquifer particles for Fe and As and detailed characterization of bacterial species interacting with As using routine and novel microbial techniques.

On behalf of the projects working in Bangledesh, 7,500 samples and solutions were analyzed by HR-ICP-MS. In support of Dr. Van Geen's work in New Hampshire and Maine, 1,240 analyses by HR-ICP-MS and 60 analyses by XRF were made for As, Mn, U and additional constituents of potential geochemical interest or health concern. Another 240 analyses by HR-ICP-MS and over 300 sediment samples were analyzed by XRF in support of the field study on increasing the efficiency of the pump-and-treat operations at the Vineland Superfund Site (Dr. Chillrud's research). For the Research Translation Core collaboration with the Rockland County Department of Health, 110 analyses for pCO₂ and TCO₂ were made on groundwater samples.

For microbial analyses, researchers have completed development of a method to extract and purify microbial DNA from aquifer systems for radiocarbon analysis. They can now collect, extract, and purify over 100 μg of carbon from groundwater. The DNA has now been shown to be free of impurities. They have collected samples from four sites in Bangladesh. Initial results show that recent recharge is not the source of organic carbon driving microbial respiration in high arsenic aquifers. This work will be submitted for publication in 2011. Concurrently, researchers have also developed and lab-tested a method to collect phospholipid fatty acids (PLFAs) from groundwater. This method will be field tested in 2011 and provide another test for constraining carbon cycling in the subsurface. In addition, they are going to use the purified DNA for metagenomic analyses.

This past year, the Core laboratory also generated synchrotron-based X-ray absorption spectroscopy data for preserved aquifer material. These analyses have included time series of 40 microprobe μSXRF scans for Fe, As, S, Mn, Ca, K and 15 samples analyzed for Fe and As speciation by XANES/EXAFS during micro-column experiments conducted at the synchrotron to test potential mechanisms for mobilization of As from aquifer solids from Bangladesh.