Main Newsletter Page
The Standard
November 2011 - Page 1
Ask The Expert: Volatile Vs. Semivolatile Organic Analysis For 1,4-Dioxane?
The primary use for 1,4-dioxane in the United States was, and still is, to stabilize chlorinated solvents (e.g., 1,1,1-trichloroethane). This compound is considered an emerging contaminant; its possible presence has resulted in the recent reinvestigation of some remediated sites because 1,4-dioxane was not a compound that was evaluated during the initial site investigation. Steps are currently being taken to eliminate the use of 1,4-dioxane as a chlorinated solvent stabilizer; due to the prevalent use of 1,4-dioxane in the past, this compound has become a compound of potential concern at industrial sites where chlorinated solvents were previously used.
The compound 1,4-dioxane can be analyzed as both a volatile organic compound and as a semivolatile organic compound by GC/MS. Typically, the GC/MS instruments are operated in selected ion monitoring (SIM) mode to increase instrument sensitivity and obtain lower detection limits. Low detection limits are desired for this compound because it is a suspected carcinogen and most site cleanup goals are in the single-digit part-per-billion range. For example, on October 19, 2011, the State of New Hampshire announced that the Drinking Water and Groundwater Bureau of the Water Division has requested all public water supplies to sample for 1,4-dioxane using a reporting limit of 0.25 µg/L; beginning in November 2011, the Waste Management Division will require all analyses for 1,4-dioxane to utilize an analytical method that achieves a reporting limit of 0.25 µg/L.
There are pros and cons associated with analyzing 1,4-dioxane as either a volatile organic compound or a semivolatile organic compound. One advantage of analyzing this compound as a volatile organic compound is the absence of a laboratory extraction step, which saves both time and money; one disadvantage is that carryover after analyzing samples and standards with concentrations of 1,4-dioxane at the calibration midpoint and above is sometimes observed. Several disadvantages exist when analyzing 1,4-dioxane as a semivolatile organic compound, including the high solubility of the compound in water, potential loss during concentration, and the possibility that the compound may elute very close to the extraction solvent chosen to extract the sample on the chromatographic column - resulting in the 1,4-dioxane peak on the chromatogram potentially being obscured.
Environmental Standards has experience in dealing with both analytical techniques for 1,4-dioxane and has worked with laboratories to modify the analytical methods to eliminate or reduce the issues observed with each analytical technique. Please contact Principal Chemist David Blye or Technical Director of Chemistry/Principal Rock Vitale at 610-935-5577 with questions concerning 1,4-dioxane analysis.
Perchlorate And Other Emerging Contaminants Continue To Be A Focus
An emerging contaminant (EC) is a chemical or material characterized by a perceived, potential, or real threat to human health or the environment or by a lack of published health standards. A contaminant also may be "emerging" because of the discovery of a new source or a new pathway to humans. The Federal Facilities Restoration and Reuse Office recently published the following EC fact sheets:
Perchlorate is one (highly controversial) example of an EC. This compound has a wide range of applications, including the manufacture of military munitions (mortars, flares, and grenades), solid rocket fuel, pyrotechnics and fireworks, blasting agents, matches, air bags, and certain types of fertilizers. Perchlorate has reportedly been detected in the groundwater at 54 federal facilities and 29 private (Superfund or RCRA) sites in 26 states. US EPA and states are addressing the contamination at many of the sites through investigations and response actions (e.g., blending, providing alternative water supplies, remediating groundwater contamination) or through enforcement actions against potentially responsible parties (PRPs).
Vapor intrusion also is being examined as an EC because of concerns about the
vapor intrusion pathway. Volatile chemicals in contaminated soils and/or groundwater can emit vapors that may migrate through the subsurface soils and into indoor air spaces of overlying buildings.
For additional information about ECs, visit the following:
Laboratory News
Pace Analytical Purchases
Xenco Boca Raton Laboratory
Pace Analytical announced on July 25, 2011, that it purchased the assets of the Xenco Boca Raton, Florida, laboratory along with the Miami Lakes Service Center. The laboratories will operate as a part of a fully integrated laboratory network.
ALS Group Acquires Columbia Analytical Services
On November 1, 2011, ALS Group acquired Columbia Analytical Services, an environmental testing laboratory network headquartered in Kelso, Washington, with six locations in the United States.
United States House Of Representatives Passes Coal Ash Bill
On October 14, 2011, the United States House of Representatives passed the "Coal Residuals Reuses and Management Act"
(HR 2273), which prohibits comprehensive federal oversight of coal completion residue (CCR). A critical element of the bill is that CCR does not receive a hazardous waste designation, and is, therefore, not subject to federal regulation.
HR 2273 establishes national standards for coal ash disposal (an obvious reaction to the 2008 Tennessee Valley incident) and requires state-administered permit programs to create enforceable regulations; these regulations are applicable to groundwater monitoring and landfill linings and establish criteria for corrective actions and structures. A major goal of this bill is to protect coal ash recycling and to strengthen its beneficial reuse. CCRs are typically recycled into common construction items such as cement and roofing shingles.
Environmental Standards is closely monitoring this important pending legislation. For the most recent information, contact Technical Director of Chemistry/Principal Rock Vitale at 610-935-5577.
|
