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GeoInsighter Fall / Winter 2000 Newsletter
Volume 5 Number 3

Gasoline Oxygenates Attract Attention of NHDES

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The impact of gasoline oxygenates in reformulated gasoline (RFG), specifically methyl-tertiary-butyl ether (MTBE), has been a topic of considerable debate within environmental agencies in New England. The presence of MTBE has been documented in many water supply wells throughout New England. During the 1999-2000 New Hampshire legislative session, House Bill 1569 was passed and signed into law that required the New Hampshire Department of Environmental Services (NHDES) to study the amount of RFG being delivered to those New Hampshire counties where the use of RFG is not required. The Air Resources Division of the NHDES conducted a survey of six northern and western counties. The survey consisted of the sampling of gasoline for analysis of oxygenates. Also included in the survey were gasoline samples collected from Merrimack County in southern New Hampshire where RFG has been required on a year-round basis since 1995. The samples from Merrimack County were intended to be reflective of RFG being delivered to all four southern counties where RFG is sold year-round. 

The results of the sampling and analysis were surprising to the NHDES. In addition to MTBE, four other oxygenates were detected: tertiary-butyl alcohol (TBA), tertiary-amyl methyl ether (TAME), ethyl tertiary-butyl ether (EtBE), and di-isopropyl ether (DIPE). It is not known if TBA, which is an oxygenate and a degradation by-product of either MTBE or EtBE, was an intended additive. 

As a result of this study, NHDES has concluded that leaks and spills of gasoline may potentially contain other oxygenates besides MTBE. Therefore, effective January 1, 2001, NHDES is requiring the analysis of not only MTBE in ground water and soil samples, but also TAME, EtBE, DIPE, and TBA when sampling ground water or soil for volatile organic compounds (VOCs) where the date of the release is 1995 or later. Current sampling and preservation protocol for VOCs do not need to be amended for the oxygenates. Based upon a laboratory survey performed by GeoInsight, the addition of these compounds will increase laboratory costs by an average of 15 to 25 percent. 

The NHDES has not established ground water standards for the gasoline oxygenates other than MTBE, which is currently at 13 parts per billion (ppb). According to the NHDES, the information gathered by consultants conducting ground water and soil studies will be evaluated along with published toxicological data to evaluate the need for additional ground water and soil standards. Once sufficient data has been gathered by the NHDES, the regulated community in New Hampshire may be faced with additional ground water and soil standards and challenges to remediation.

Brian D. Kisiel
bdkisiel@geoinc.com

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