Methyl tert-Butyl Ether Occurrence and Related Factors in Public and Private Wells in Southeast New Hampshire

• Published in: Environmental science & technology Vol. 39; no. 1; pp. 9 - 16
• Main Authors: Ayotte, Joseph D, Argue, Denise M, McGarry, Frederick J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.01.2005
• Subjects: Applied sciences; Carcinogens - analysis; Contamination; Drinking water and swimming-pool water. Desalination; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring; Exact sciences and technology; Geological Phenomena; Geology; Humans; Methyl Ethers - analysis; MTBE; New Hampshire; Pollutants; Pollution; Pollution, environment geology; Private Sector; Public Sector; Water Supply; Water treatment and pollution; Wells; United States; North America; America; New Hampshire; United States > US; USA, New Hampshire; Antiknock additive; Drinking water; Depth dose relation; Ether; Urban area; Spatial variation; Water well; Gasoline; Water quality; Water pollution; Sampling; Organic compounds; Concentration distribution; Ground water
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es049549e

The occurrence of methyl tert-butyl ether (MTBE) in water from public wells in New Hampshire has increased steadily over the past several years. Using a laboratory reporting level of 0.2 μg/L, 40% of samples from public wells and 21% from private wells in southeast New Hampshire have measurable concentrations of MTBE. The rate of occurrence of MTBE varied significantly for public wells by establishment type; for example, 63% of public wells serving residential properties have MTBE concentrations above 0.2 μg/L, whereas lower rates were found for schools (21%). MTBE concentrations correlate strongly with urban factors, such as population density. Surprisingly, MTBE was correlated positively with well depth for public supply wells. Well depth is inversely related to yield in New Hampshire bedrock wells, which may mean that there is less opportunity for dilution of MTBE captured by deep wells. Another possibility is that the source(s) of water to low-yield wells may be dominated by leakage from potentially contaminated shallow groundwater through near-surface fractures or along the well casing. These wells may also have relatively large contributing areas (due to low recharge at the bedrock surface) and therefore have a greater chance of intersecting MTBE sources. This finding is significant because deep bedrock wells are often considered to be less vulnerable to contamination than shallow wells, and in southeast New Hampshire, wells are being drilled deeper in search of increased supply.