Iodine as a sensitive tracer for detecting influence of organic-rich shale in shallow groundwater

Zunli Lu, Sunshyne T. Hummel, Laura K. Lautz, Gregory D. Hoke, Xiaoli Zhou, James Leone, Donald I. Siegel

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Public and regulatory agencies are concerned over the potential for drinking water contamination related to high-volume hydraulic fracturing (hydrofracking) of the Marcellus shale in Pennsylvania and in New York State (NYS), where exploitation of Marcellus gas has not yet begun. Unique natural tracers are helpful for distinguishing the influence of formation water and/or flow-back water. Here we use halogen concentrations, particularly bromine and iodine, to characterize natural variability of baseline water chemistry in the southern tier of NYS. Majority of streams and drinking water wells have Br and I concentrations below 1 and 0.1. μM, respectively, a range typical for relatively pristine surface water and shallow groundwater. Wells that have higher Br and I concentrations are likely affected by formation waters. Br/I ratios indicate two different sources of formation waters in these wells, possibly controlled by geologic settings. Our results suggest that iodine, combined with other halogens, may be a novel and sensitive tool for fingerprinting trace levels of formation water signal in drinking water sources.

Original languageEnglish (US)
Pages (from-to)29-36
Number of pages8
JournalApplied Geochemistry
StatePublished - Sep 1 2015

ASJC Scopus subject areas

  • Environmental Chemistry
  • Pollution
  • Geochemistry and Petrology


Dive into the research topics of 'Iodine as a sensitive tracer for detecting influence of organic-rich shale in shallow groundwater'. Together they form a unique fingerprint.

Cite this