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Title:	Field screening method for perchlorate in water and soil
Authors:	Thorne, Philip G.
Keywords:	Water--Purification--Perchlorate removal Colorimetry
Publisher:	Cold Regions Research and Engineering Laboratory (U.S.) Engineer Research and Development Center (U.S.)
Series/Report no.:	ERDC/CRREL ; TR-04-8.
Abstract:	Low concentrations (μg/L) of the perchlorate anion, ClO₄-, have been measured in drinking water supplies in many states throughout the United States. Federal and state regulatory agencies are concerned about the possible adverse effects of perchlorate contamination, as the anion is known to target the human thyroid gland and its metabolic-hormone-producing function. The provisional action level for drinking water established by the EPA and adopted by several states is 18 μg/L (18 ppb) perchlorate; however, other states have set levels as low as 1–4 μg/L. The major sources of perchlorate contamination in surface and ground waters are propellant manufacturers, military installations, defense contractors, and agriculture. A reliable and inexpensive colorimetric method for perchlorate in water and soil extracts has been developed and tested with surface water, well water, bioreactor effluent, and soil extracts. The detection limit for water is 1 μg/L and 0.3 μg/g for spiked soils. A 0.5-L sample of water or a 1-mL sample of aqueous soil extract is passed through a solid-phase extraction cartridge that has been conditioned with a perchlorate-specific ion-pair reagent. Perchlorate, as well as small quantities of chlorate and major ions, is retained. A rinse step removes the interferences and the perchlorate is eluted into an ion-pairing dye in a 13- × 100-mm test tube. A 1-mL aliquot of xylene is added, the tube is shaken, and the dye-pair extracts into the xylene that separates into a layer lying in the light path of a standard portable spectrophotometer. Results from nearly 100 well water and bioreactor samples show excellent agreement with EPA Method 314 over the range of 1–225 μg/L (slope = 1.11, R2 = 0.913). Some false positives were encountered in some wells. A cleanup method was developed that can eliminate false positives due to humic substances. The colorimetric method is being adapted to an automated on-line monitor.
Description:	Technical Report
URI:	http://hdl.handle.net/11681/5369
Appears in Collections:	Technical Report