Carcinogens – Eight Substances Added To The List

From the 12 June 2011 Medical News Today article

Eight substances have been added to the list of carcinogens by the HSS (US Department of Health and Human Services) today. The Report of Carcinogens has added formaldehyde, aristolochic acids, o-nitrotoluene, captafol, cobalt-tungsten carbide (in powder or hard metal form), riddelliine, certain inhalable glass wool fibers, and styrene to the list of carcinogens….

…The NTP prepares the Report on Carcinogens for the HHS Secretary. It is a congressionally mandated document. It identifies substances, agents, mixtures or exposures in two categories:

• Those that are known to be human carcinogens
• Those reasonably anticipated to be human carcinogens

A substance which is included in the list in the Report on Carcinogens does not in itself mean it causes cancer. There are many factors which cause cancer, including how long the human is exposed and a person’s susceptibility to a particular substance.

There are now 240 carcinogens in the list.

Related Resources

• 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

Related articles

• Cancer Link?: Styrofoam Chemical Added to Govt. List (abcnews.go.com)
• Industry Bucks At NIH’s List Of New Carcinogens Styrene, Formaldehyde (MedicalNewsToday)
• It’s official: Formaldehyde is a “known Human Carcinogens”- via ProPublica and Democracy Now (euzicasa.wordpress.com)

Haz-Map updated to include more information about occupational exposures to hazardous substances

Search  as

From a 4 May 2011 National Library of Medicine listerv item 

Haz-Map now includes 1212 new chemical agents and twelve chemical
categories with significance regarding occupational exposure.

The twelve categories of chemical agents include metals, solvents,
pesticides, mineral dusts, toxic gases and vapors, plastics and rubber,
biological agents, nitrogen compounds, dyes, physical agents, other
classes, and other uses.
http://hazmap.nlm.nih.gov/cgi-bin/hazmap_cgi?level=0&tree=Agent

Haz-Map is an occupational toxicology database designed to link jobs to
hazardous job tasks which are linked to occupational diseases and their
symptoms.

The Haz-Map Jobs table is based on the 1997 Standard Occupational
Classification (SOC) system. The Industries table is based on the North
American Industry Classification System (NAICS). The Diseases table is
based on the International Classification of Diseases (ICD-9).

Information from textbooks, journal articles, and electronic databases was
classified and summarized to create the database.

Other NLM toxicology databases include

• Household Products Database -Potential health effects of chemicals for common household products
• Tox Town -Interactive guide to potentially toxic substances and environmental health issues in everyday places

• TOXNET –Databases on hazardous chemicals, environmental health, and toxic releases

Related Articles

• NIOSH Chemical Hazards V2.1 for iPhone and iPad Released (themactrack.com)
• Who’s exposed – and what can they do about it? Biomonitoring for consumer products and workplaces (scienceblogs.com)
• US must strengthen efforts to restrict chemicals that threaten health, say researchers (yubanet.com)
• Chemical law fails to protect kids’ health: MDs (cbc.ca)
• Environmental Toxins (education.com)
• 83,000 Chemicals And Growing: Is It Time To Stop Regulating and Start Banning? (worldtruthtoday.com)
• The Environment Factor: How They Arises and What Should be Done? (socyberty.com)
• HazMasterG3 Only CBRNE/HME System Compatible With Army’s First SmartPhone (prweb.com)
• Study describes health effects of occupational exposures in Paducah Gaseous Diffusion Plant workers (physorg.com)
• Women Action For Ecology WOMEN MORE VULNERABLE TO TOXIC EFFECTS OF… (preetlari.wordpress.com)

PubMed Toxicology Subset Streamlines Biomedical Searches in the Professional Literature

Image via Wikipedia

From a March 25 2011  NLM-TOX-ENVIRO-HEALTH-L NOTICE

The National Library of Medicine (NLM) PubMed database offers a toxicology subset. This subset is created by NLM’s Specialized Information Services (SIS) to facilitate searching for subjects in the area of toxicology.

Here is how to limit searches to toxicology:

• Go to Pubmed
• Click on Limits (above search box), and select Toxicology under Subsets

OR

Click on Advanced Search (above search box) , then Limits while building the search

The toxicology subset can also be placed in a search as “tox [sb]”.   Example:   lead AND tox [sb]

The PubMed database comprises more than 19 million citations for biomedical articles from MEDLINE and life science journals. Citations may include links to full-text articles from PubMed Central or publisher web sites.

Here are some PubMed tutorials and guides

• PubMed Tutorial (National Library of Medicine)
• PubMed Online Training [Quick animated tours, Webcasts, detailed tutorial, Webcasts, and more] (National Library of Medicine)
• PubMed MeSH searching (sullivanlibrary.wordpress.com)
• PubMed Search Help Items (jflahiff.wordpress.com)
• PubMed Toxicology Subset Streamlines Biomedical Searches in the Professional Literature(jflahiff.wordpress.com

Related Articles

• PubMed Health Provides Disease and Treatment Information for Consumers (jflahiff.wordpress.com)
• PubMed Mobile Beta (jflahiff.wordpress.com)
• Paper on NCBI and Wikipedia published in PLoS Currents: Tree of Life (iphylo.blogspot.com)

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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