Health and Medical News and Resources

General interest items edited by Janice Flahiff

Even The Cleanest Wastewater Contributes To More ‘Super Bacteria’

 

Clean drinking water...not self-evident for ev...

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From the 16 November 2011 Medical News Today article

A new University of Minnesota study reveals that the release of treated municipal wastewater – even wastewater treated by the highest-quality treatment technology – can have a significant effect on the quantities of antibiotic-resistant bacteria, often referred to as “superbacteria,” in surface waters.

The study also suggests that wastewater treated using standard technologies probably contains far greater quantities of antibiotic-resistant genes, but this likely goes unnoticed because background levels of bacteria are normally much higher than the water studied in this research.

The new study is led by civil engineering associate professor Timothy LaPara in the University of Minnesota, Twin Cities College of Science and Engineering. The study is published in the most recent issue ofEnvironmental Science and Technology, a journal of the American Chemical Society. The research was part of a unique class project in a graduate-level civil engineering class at the University of Minnesota focused on environmental microbiology.

 

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November 16, 2011 Posted by | Consumer Health, Public Health | , , , , | Leave a comment

The green machine: Algae clean wastewater, convert to biodiesel

The green machine: Algae clean wastewater, convert to biodiesel

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Professor Jeff Lodge and graduate student Eric Lannan explore algae as a biodiesel fuel.

From a February 17 2011 Eureka news alert

(Rochester Institute of Technology) Researchers at RIT are developing biodiesel from microalgae grown in wastewater. The project is doubly “green” because algae consume nitrates and phosphates and reduce bacteria and toxins in the water. The end result: clean wastewater and stock for a promising biofuel.

RIT researchers take algae out of the lab

Let algae do the dirty work.

Researchers at Rochester Institute of Technology are developing biodiesel from microalgae grown in wastewater. The project is doubly “green” because algae consume nitrates and phosphates and reduce bacteria and toxins in the water. The end result: clean wastewater and stock for a promising biofuel.

The purified wastewater can be channeled back into receiving bodies of water at treatment plants, while the biodiesel can fuel buses, construction vehicles and farm equipment. Algae could replace diesel’s telltale black puffs of exhaust with cleaner emissions low in the sulfur and particulates that accompany fossil fuels.

Algae have a lot of advantages. They are cheaper and faster to grow than corn, which requires nutrient-rich soil, fertilizer and insecticide. Factor in the fuel used to harvest and transport corn and ethanol starts to look complicated.

In contrast, algae are much simpler organisms. They use photosynthesis to convert sunlight into energy. They need only water—ponds or tanks to grow in—sunlight and carbon dioxide.

“Algae—as a renewable feedstock—grow a lot quicker than crops of corn or soybeans,” says Eric Lannan, who is working on his master’s degree in mechanical engineering at RIT. “We can start a new batch of algae about every seven days. It’s a more continuous source that could offset 50 percent of our total gas use for equipment that uses diesel.”

Cold weather is an issue for biodiesel fuels.

“The one big drawback is that biodiesel does freeze at a higher temperature,” says Jeff Lodge, associate professor of biological sciences at RIT. “It doesn’t matter what kind of diesel fuel you have, if it gets too cold, the engine’s not starting. It gels up. It’s possible to blend various types of biodiesel—algae derived with soybeans or some other type—to generate a biodiesel with a more favorable pour point that flows easily.”

Lannan’s graduate research in biofuels led him to Lodge’s biology lab. With the help of chemistry major Emily Young, they isolated and extracted valuable fats, or lipids, algae produce and yielded tiny amounts of a golden-colored biodiesel. They are growing the alga strain Scenedesmus, a single-cell organism, using wastewater from the Frank E. Van Lare Wastewater Treatment Plant in Irondequoit, N.Y.

“It’s key to what we’re doing here,” Lodge says. “Algae will take out all the ammonia—99 percent—88 percent of the nitrate and 99 percent of the phosphate from the wastewater — all those nutrients you worry about dumping into the receiving water. In three to five days, pathogens are gone. We’ve got data to show that the coliform counts are dramatically reduced below the level that’s allowed to go out into Lake Ontario.”

Lodge and Lannan ramped up their algae production from 30 gallons of wastewater in a lab at RIT to 100 gallons in a 4-foot-by-7-foot long tank at Environmental Energy Technologies, an RIT spinoff. Lannan’s graduate thesis advisor Ali Ogut, professor of mechanical engineering, is the company’s president and CTO. In the spring, the researchers will build a mobile greenhouse at the Irondequoit wastewater treatment plant and scale up production to as much as 1,000 gallons of wastewater.

Northern Biodiesel, located in Wayne County, will purify the lipids from the algae and convert them into biodiesel for the RIT researchers.

February 19, 2011 Posted by | Public Health | , , , , | 1 Comment

Long-lasting chemicals flooding wastewater treatment plants threaten the environment and human health

Long-lasting chemicals flooding wastewater treatment plants threaten the environment and human health

Rolf Halden is a researcher at the Biodesign Institute at Arizona State University.

 

From a December 21, 2010 Eureka news release

Every hour, an enormous quantity and variety of manmade chemicals, having reached the end of their useful lifespan, flood into wastewater treatment plants. These large-scale processing facilities, however, are designed only to remove nutrients, turbidity and oxygen-depleting human waste, and not the multitude of chemicals put to residential, institutional, commercial and industrial use. So what happens to these chemicals, some of which may be toxic to humans and the environment? Do they get destroyed during wastewater treatment or do they wind up in the environment with unknown consequences?

New research by Rolf Halden and colleagues at the Biodesign Institute at Arizona State University seeks to address such questions. The group’s results, reported recently in the Journal of Environmental Monitoring,*** suggest that a number of high production volume (HPV) chemicals—that is, those used in the U.S. at rates exceeding 1 million pounds per year, are likely to become sequestered in post-treatment sludge and from there, enter the environment when these so-called biosolids are deposited on land.

As Halden notes, over 4000 chemicals in common usage in the U.S. qualify as HPV chemicals, the vast majority of which have never been evaluated in terms of exotoxicity (their potential to adversely affect ecosystems), or for the risks they may pose to humans. “With each of these compounds, we are engaged in an experiment conducted on a nationwide scale,” says Halden; “Odds are, some of these chemicals will turn out to be bad players and will pose problems for ecosystems, public health or both.”

Unfortunately, it is neither technically nor economically feasible to perform the kind of detailed analyses necessary to declare this vast swirl of chemicals safe for humans or environmentally benign following wastewater treatment. Instead, Halden’s efforts are aimed at narrowing the field of potentially troublesome chemicals, by defining traits likely to cause some chemicals to persist in the environment. To do this, the group applied a new empirical model for estimating the fraction of mass loading of chemicals in raw sewage expected to endure in digested sludge.

Chemicals which become sequestered in digested sewage sludge are a potential cause for concern in part because the treated sludge is often subsequently applied to land, including land designated for agricultural use. Halden’s group screened some 207 HPV chemicals, using a model that predicted that two thirds of these compounds are likely to accumulate in digested sludge to greater than fifty percent of their initial mass loading in raw sewage. Eleven of these chemicals were flagged as compounds of special concern and deemed potential hazards to human and environmental health.

Three principal criteria dictated the selection of these problem chemicals: (a) their propensity to accumulate and persist in sludge in large amounts (b) structural characteristics suggestive of environmental persistence on land following biosolids recycling, and (c) unfavorable ecotoxicity threshold values, whether these have been experimentally determined or were forecasted with computer models.

As Halden explains, certain classes of chemicals possess physical characteristics that make them likelier to resist breakdown during wastewater treatment. Of particular concern are hydrophobic organic chemicals. As their name implies, such chemicals are ‘afraid’ of water and preferentially attach themselves to particulate matter, thereby becoming part of the primary and secondary sludge. This characteristic trait limits the availability of hydrophobic chemicals to aerobic and anaerobic microorganisms during sewage treatment and sludge digestion.

Rather than being broken down, such chemicals can become enriched in municipal biosolids by several orders of magnitude. Through this process, substances in heavy usage, like HPV chemicals, can accumulate as pollutants in municipal sludge to parts per million (ppm) concentrations. “It’s like vacuum cleaning your home,” says Halden. “When the carpet is clean, the vacuum bag holds a concentrated burden of dirt. By anology, the generation of biosolids enriched in non-biodegradable pollutants are the price you pay when purifying domestic sewage for water reuse.”

In order to better gauge which chemicals may go on to present human health and environmental risks following sequestration in sludge, the group conducted a computer or in silico analysis. The method provides a streamlined and economically attractive means of isolating those chemicals deserving more in-depth field analysis. The group applied a new empirical model able to predict the fraction of total mass of a hydrophobic chemical likely to persist in biosolids after wastewater treatment.

Another advantage of the new model, applied by Halden and Assistant Professor Randhir Deo from the University of Guam, is simplicity. The model only requires two input values in order to estimate a chemical’s environmental persistence. The chemicals to be screened were taken from the High Production Volume Information System database maintained by the EPA to monitor the environmental fate of chemicals produced in amounts exceeding 1 million pounds per year.

The empirical model was developed and tweaked to produce the best agreement between the mathematical framework based on a given chemical’s physical properties and actual measurements derived from large sewage treatment plants. The physical characteristic found to play the largest role in a chemical’s persistence in sludge was its sorption potential—the tendency of molecules of the chemical to adhere to the surface of other molecules. In the case of the HPV chemicals under consideration, high sorption values among hydrophobic chemicals caused them to stick to other particles and be sequestered from the degradative processes used to treat wastewater.

The bulk of the chemicals included in the HPV study were used for industrial purposes and included antidegradants, antioxidants, metal chelators, intermediates, by-products, catalysts, flame retardants, phenylating agents, plasticizers, heat storage and transfer agents, lubricants, solvents, anticorrosive agents, and others. The study also identified five mass-produced chemicals used as flavors and fragrances that were predicted to persist in sludge in fifty percent or greater amounts of their initial mass loading in raw sewage.

Once chemicals likely to persist in sludge were identified, estimates of their toxicity were examined. Those with high persistence levels and high environmental toxicity made the enemies list of chemicals posing the greatest potential hazard. Prominent among the toxic chemicals were the so-called organohalogen compounds, seven of which were found to accumulate in substantial quantity in treated sludge and displayed half-lives in soil estimated to range from 120 to 360 days.

Perhaps of greatest concern are halogenated chemicals known as organobromines—popular ingredients in a range of flame retardant products, which have subsequently been identified in bird tissues, in egg pools of herring gulls, and in dust samples. Halden insists that better monitoring of just such chemicals is essential for understanding their trajectory and mitigating risks to human health and the environment.

“Our work is directed at identifying problematic compounds before they cause harm to the environment and people. Environmental chemists often can foretell adverse outcomes. What’s lacking are regulations to translate that knowledge into pollution prevention,” says Halden. “Cleaning up after the fact, is costly and hard to do.”

Some related informational links

  • Environmental Health and Toxicology (specialized information services from the US National Institutes of Health and US National Library of Medicine)
    • HazMap -an occupational toxicology database designed to link jobs to hazardous job tasks which are linked to occupational diseases and their symptoms. It is a relational database of chemicals, jobs and diseases.
    • ToxNet – Databases on toxicology, hazardous chemicals, environmental health, and toxic releases
    • Household Products Databases – This database links over 8,000 consumer brands to health effects from Material Safety Data Sheets (MSDS) provided by the manufacturers and allows scientists and consumers to research products based on chemical ingredients
    • and many more databases..
  • Toxicology Web links from NIH & NLM (extensive list of govt, non-govt, and international Web sites)
  • Toxicology Resources especially for the public (from NIH and NLM), including ToxTown and ToxMap

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January 3, 2011 Posted by | Biomedical Research Resources, Consumer Health, Consumer Safety, Educational Resources (High School/Early College(, Finding Aids/Directories, Librarian Resources, Medical and Health Research News, Professional Health Care Resources, Public Health | , , , | Leave a comment

   

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