텍사스 주립대학 알링턴 캠퍼스 화학 및 생화학 학부의 케빈 슈크(Kevin Schug) 부교수와 그의 팀은 최근 바넷 셰일(Barnett Shale) 지역 부근의 100개의 사설 지하용수 시설을 조사하였다. 그 결과, 천연가스 추출 및 채광 지역 부근에서 오염 발생원인 비소와 셀렌 등이 가장 높은 수치로 기록되었음을 발견하였다.

위와 같은 북부 텍사스 지하용수 시설 연구의 결과는 최근 환경 과학 및 기술(Environmental Science & Technology) 온라인 저널에 게재되었다. 이 상호심사 논문은 수집된 용수 샘플에서 비소, 바륨, 셀렌, 스트론튬 등의 금속이 추출되는 여부에 집중하였던 것으로 알려졌다. 위 같은 종류의 많은 중금속들은 지하수에서 낮은 수치로 자주 자연스럽게 발생하지만, 천연가스 추출 활동으로 인한 방해가 높은 수치로의 발현을 촉진시키는 것으로 드러났다.

July 29, 2013 -- A new study of 100 private water wells in and near the Barnett Shale showed elevated levels of potential contaminants such as arsenic and selenium closest to natural gas extraction sites, according to a team of researchers that was led by UT Arlington associate professor of chemistry and biochemistry, Kevin Schug.

The results of the North Texas well study were recently published online by the journal Environmental Science & Technology. The peer-reviewed paper focuses on the presence of metals such as arsenic, barium, selenium and strontium in water samples. Many of these heavy metals occur naturally at low levels in groundwater, but disturbances from natural gas extraction activities could cause them to occur at elevated levels.

"This study alone can't conclusively identify the exact causes of elevated levels of contaminants in areas near natural gas drilling, but it does provide a powerful argument for continued research," said Brian Fontenot, a UT Arlington graduate with a doctorate in quantitative biology and lead author on the new paper.

He added: "We expect this to be the first of multiple projects that will ultimately help the scientific community, the natural gas industry, and most importantly, the public, understand the effects of natural gas drilling on water quality."

Researchers believe the increased presence of metals could be due to a variety of factors including: industrial accidents such as faulty gas well casings; mechanical vibrations from natural gas drilling activity disturbing particles in neglected water well equipment; or the lowering of water tables through drought or the removal of water used for the hydraulic fracturing process. Any of these scenarios could release dangerous compounds into shallow groundwater.

Researchers gathered samples from private water wells of varying depth within a 13 county area in or near the Barnett Shale in North Texas over four months in the summer and fall of 2011. Ninety-one samples were drawn from what they termed "active extraction areas," or areas that had one or more gas wells within a five kilometer radius. Another nine samples were taken from sites either inside the Barnett Shale and more than 14 kilometers from a natural gas drilling site, or from sites outside the Barnett Shale altogether. The locations of those sites were referred to as "non-active/reference areas" in the study.

Researchers accepted no outside funding to ensure the integrity of the study. They compared the samples to historical data on water wells in these counties from the Texas Water Development Board groundwater database for 1989-1999, prior to the proliferation of natural gas drilling.

In addition to standard water quality tests, the researchers used gas chromatography - mass spectrometry (GC-MS), headspace gas chromatography (HS-GC) and inductively coupled plasma-mass spectrometry (ICP-MS). Many of the tests were conducted in the Shimadzu Center for Advanced Analytical Chemistry on the UT Arlington campus.

"Natural gas drilling is one of the most talked about issues in North Texas and throughout the country. This study was an opportunity for us to use our knowledge of chemistry and statistical analysis to put people's concerns to the test and find out whether they would be backed by scientific data," said Schug, who is also the Shimadzu Distinguished Professor of Analytical Chemistry in the UT Arlington College of Science.

[출처: Waterworld / 2013년 7월 29일]