Daily Archives: July 25, 2015

Obama Administration: ISIS is a Distraction? Huh? What?

Ms. Carly Fiorina responds:

 

h/t: Crowder

Monitoring Data Below Detection Limits Lowers Median Pesticide Concentrations

Hansen CT, Ritz C, Gerhard D, Jensen JE, Streibig JC. Re-evaluation of groundwater monitoring data for glyphosate and bentazone by taking detection limits into account. The Science of the total environment. 2015 Jul 17;536:68-71. doi: 10.1016/j.scitotenv.2015.07.047.

Current regulatory assessment of pesticide contamination of Danish groundwater is exclusively based on samples with pesticide concentrations above detection limit. Here we demonstrate that a realistic quantification of pesticide contamination requires the inclusion of “non-detect” samples i.e. samples with concentrations below the detection limit, as left-censored observations. The median calculated pesticide concentrations are shown to be reduced 104 to 105 fold for two representative herbicides (glyphosate and bentazone) relative to the median concentrations based upon observations above detection limits alone.

Assessment of Hydraulic Fracturing Depths in the US

Jackson RB, Lowry ER, Pickle A, Kang M, DiGiulio D, Zhao K. The Depths of Hydraulic Fracturing and Accompanying Water Use Across the United States. Environmental Science and Technology. 2015 Jul 21.

Reports highlight the safety of hydraulic fracturing for drinking water if it occurs “many hundreds of meters to kilometers underground”. To our knowledge, however, no comprehensive analysis of hydraulic fracturing depths exists. Based on fracturing depths and water use for ∼44 000 wells reported between 2010 and 2013, the average fracturing depth across the United States was 8300 ft (∼2500 m). Many wells (6900; 16%) were fractured less than a mile from the surface, and 2600 wells (6%) were fractured above 3000 ft (900 m), particularly in Texas (850 wells), California (720), Arkansas (310), and Wyoming (300). Average water use per well nationally was 2 400 000 gallons (9 200 000 L), led by Arkansas (5 200 000 gallons), Louisiana (5 100 000 gallons), West Virginia (5 000 000 gallons), and Pennsylvania (4 500 000 gallons). Two thousand wells (∼5%) shallower than one mile and 350 wells (∼1%) shallower than 3000 ft were hydraulically fractured with >1 million gallons of water, particularly in Arkansas, New Mexico, Texas, Pennsylvania, and California. Because hydraulic fractures can propagate 2000 ft upward, shallow wells may warrant special safeguards, including a mandatory registry of locations, full chemical disclosure, and, where horizontal drilling is used, predrilling water testing to a radius 1000 ft beyond the greatest lateral extent.