Parker, et al. (2008) Perchlorate in groundwater: A synoptic survey of pristine sites in the contiguous United States. Environ. Sci. Technol.
42(5): 1465-1471. Authors used a network of volunteers to collect 326 groundwater samples, avoiding areas of EAP-documented use or release. Of the 326 samples, 147 (45%) were below the method detection limit (40 ng/L), 42 (13%) were between the MDL and the method reporting limit (120 ng/L). Of the 137 samples that could be quantified, most (109) contained less than 1000 ng/L of perchlorate; the remaining 28 contained from 1000-10,400 ng/L. Perchlorate concentrations were positively-correlated with nitrate levels, but not with chloride concentrations.
Historical correspondence within DoD and between DoD and other federal agencies and states related to perchlorate.
Tran, N., et al. (2008) Thyroid stimulating hormone increases active transport of perchlorate into thyroid cells. Am J. Physiol Endocrinol. Metab., 26 Feb 2008 (e-pub ahead of publication). Using an in vitro system, authors found that perchlorate is actively transported into thyroid cells, and this transport increases in a dose-related manner when treated with TSH. Addition of iodine appeared to competitively-inhibit perchlorate transport. The highest concentration of perchlorate, 100 micromole/L, did not inhibit cell proliferation over a 72 hour period.
Proposed 2007 Legislation Relating to Perchlorate