Daily Archives: August 22, 2012

Tap water is not sterile, microbial ecology affected by pH

This study in many respects confirms what is already known.

Pinto, A.J,Xi, C., and Raskin, L. Bacterial Community Structure in the Drinking Water Microbiome Is Governed by Filtration Processes. Environ. Sci. Technol., 2012, 46 (16), pp 8851–8859. DOI: 10.1021/es302042t

The bacterial community structure of a drinking water microbiome was characterized over three seasons using 16S rRNA gene based pyrosequencing of samples obtained from source water (a mix of a groundwater and a surface water), different points in a drinking water plant operated to treat this source water, and in the associated drinking water distribution system. Even though the source water was shown to seed the drinking water microbiome, treatment process operations limit the source water’s influence on the distribution system bacterial community. Rather, in this plant, filtration by dual media rapid sand filters played a primary role in shaping the distribution system bacterial community over seasonal time scales as the filters harbored a stable bacterial community that seeded the water treatment processes past filtration. Bacterial taxa that colonized the filter and sloughed off in the filter effluent were able to persist in the distribution system despite disinfection of finished water by chloramination and filter backwashing with chloraminated backwash water. Thus, filter colonization presents a possible ecological survival strategy for bacterial communities in drinking water systems, which presents an opportunity to control the drinking water microbiome by manipulating the filter microbial community. Grouping bacterial taxa based on their association with the filter helped to elucidate relationships between the abundance of bacterial groups and water quality parameters and showed that pH was the strongest regulator of the bacterial community in the sampled drinking water system.

Click here for full article (fee).

 

Long-term removal of 34 trace organic micropollutants evaluated

Zearley, T.L. and Summers, R.S. Removal of Trace Organic Micropollutants by Drinking Water Biological Filters. Environmental Science and Technology, DOI:10.1021/es301428e

Abstract:

 

The long-term removal of 34 trace organic micropollutants (<1 μg L–1) was evaluated and modeled in drinking water biological filters with sand media from a full-scale plant. The micropollutants included pesticides, pharmaceuticals, and personal care products, some of which are endocrine disrupting chemicals, and represent a wide range of uses, chemical structures, adsorbabilities, and biodegradabilities. Micropollutant removal ranged from no measurable removal (<15%) for 13 compounds to removal below the detection limit and followed one of four trends over the one year study period: steady state removal throughout, increasing removal to steady state (acclimation), decreasing removal, or no removal (recalcitrant). Removals for all 19 nonrecalcitrant compounds followed first-order kinetics when at steady state with increased removal at longer empty bed contact times (EBCT). Rate constants were calculated, 0.02–0.37 min–1, and used in a pseudo-first-order rate model with the EBCT to predict removals in laboratory biofilters at a different EBCT and influent conditions. Drinking water biofiltration has the potential to be an effective process for the control of many trace organic contaminants and a pseudo-first-order model can serve as an appropriate method for approximating performance.

Click here for full paper (fee).

 

Press Spin: National Review tells Dr. Michael Mann to “get lost”

As explained here, the National Review has responded to a letter from attorneys representing Dr. Michael Mann, essentially saying “get lost.” These letters have already been made available publically on the interent, and so I am providing them below.

It is not my intention to be the judge in this dispute. My view is that science has progressed well beyond the point of attempting to defend or refine the fabled hockystick and further attention to this issue is simply a side show, albeit a distraction. But read below and judge for yourself.

Manmade contribution to global warming not an emergency

President Václav Klaus, International Seminar on Planetary Emergencies, World Federation of Scientists, Erice, Sicily,  20 August 2012:

“The real problem is not climate or global warming, but the Global Warming Doctrine and its consequences. They may eventually bring us close to a real planetary emergency. Absolutely unnecessarily, without any connection with global temperature.”

“This doctrine, as a set of beliefs, is an ideology, if not a religion.[2] It lives independently on the science of climatology. Its disputes are not about temperature, but are part of the “conflict of ideologies”. Temperature is used and misused in these disputes. The politicians, the media and the public – misled by the very aggressive propaganda produced by the adherents of the global warming doctrine – do not see this. It is our task to help them to distinguish between what is science and what is ideology.”

Click here for the entire speech. Click here for additional comment.

Santa Clara Water District (CA) sinks own tax measure with 2 words….

“When the Santa Clara Valley Water District turned in ballot language this month to elections officials to place a $548 million parcel tax before voters, the summary of the measure was 77 words.”

“Under election law, however, summaries can be no more than 75 words.”

“When elections officials alerted the water district about the error, the district rushed to hold a board meeting and approved a new measure, this time with two fewer words.”

“The trouble is, the district didn’t post a public agenda of the Aug. 8 meeting on its website, or send it out to the media, 24 hours ahead of time as required under California’s open meetings law, the Brown Act. It missed those deadlines by less than an hour.”

Source: MercuryNews.com

Click here for the full news article…..