Tag Archives: GREEN CHEMISTRY

chemistry classroom

AGC Goes to School

 

Advancing Green Chemistry has recently been invited to speak at several universities in the Charlottesville area. Most recently, AGC staff member, Mana Sassanpour, gave a presentation on the 12 principles of green chemistry to undergraduates at the University of Virginia.  In the presentation she showed examples that the students are familiar with from their own classes and lives.

For example, principle number 5: ‘Using safer solvents and reaction conditions’. UVA undergrads use DMSO and ether as solvents in many organic chemistry labs – often without ever knowing how harmful and toxic these substances are. By showing them that pharmaceuticals that used to use similar solvents are now using water as a replacement, Mana showed how to positively alter reaction conditions. In addition, her presentation opened students to an emerging field of chemistry: mechanochemistry. Mechanochemistry does not use solvents at all, but rather relies on a grinding mechanism to start and push a reaction. This field of chemistry has been applied to the production of pepto-bismol, a compound that everyone is familiar with, making the synthesis solvent-less. The students’ favorite part was the picture of the pepto-bismol ice-cream. Yumm.

Mana’s second lecture at UVA was directed towards the Chemistry Department. This lecture was followed up with a great question and answer session, really engaging the whole audience. For the most part, each participant asked a question, creating a really involved dialogue.

Up next, Mana hopes to lecture at Eastern Mennonite University!

 

Power plant exhaust recycled in the lab.

Synopsis by Wim Thielemans, Oct 25, 2011

Stevens, JG, P Gomez, RA Bourne, TC Drage, MW George and M Poliakoff. 2011. Could the energy cost of using supercritical fluids be mitigated by using CO2 from carbon capture and storage (CCS)Green Chemistry http://dx.doi.org/10.1039/c1gc15503b.

The potential to reuse captured carbon dioxide from power plant exhaust/emissions as a mixer for other chemical reactions is shown in a unique study.

In the future, coal and natural gas fired power plants may be able to provide an abundant supply of liquid carbon dioxide (CO2) – a valuable agent used in chemical reactions in a growing number of industrial applications.

A preliminary study of this unique way to recycle and reuse carbon dioxide finds the main impurities in the power plant CO2 won’t prohibit its commercial use. The results are explained in the journal Green Chemistry.

Carbon dioxide is commonly known as the greenhouse gas formed by burning fossil fuels. Energy producers intend to capture and store the carbon dioxide they produce. To do this, they’ll convert the CO2 gas into its supercritical state – that is, changing the gas into a liquid by using extreme heat and pressure.

Converting carbon dioxide gas into a liquid is one way power plants can meet the anticipated tougher emissions standards in an effort to counteract climate change. As a liquid, carbon dioxide is also a safe solvent in other chemical production processes. It has already found applications in decaffeinating coffee and in dry cleaning.

A main advantage of supercritical carbon dioxide is that it helps produce a purer end product without toxic residue. In a typical chemical reaction with it, lowering the pressure at the end of the reaction turns the supercritical carbon dioxide fluid back into a gas. The chemical product produced during the reaction is immediately recovered. If all starting material is converted to the final product, no further purification of the end product is needed.

The supercritical state is reached by heating and compressing carbon dioxide to above its critical point of 88oF and 1071 pounds per square inch (psi). Supercritical fluids behave as liquids for dissolving chemicals but allow the chemicals to move around at high speeds as they would in gases.

Unfortunately, compressing carbon dioxide to above its critical point is energy-intensive. This makes it usually too costly for industrial-scale reactions.

However, coal and natural gas fired power plants provide a cheap source of compressed carbon dioxide. To reduce their carbon dioxide emissions, energy producers intend to capture and store the carbon dioxide they produce. Because large power plants easily produce more than half a ton of carbon dioxide per second, compressing it reduces the required space for storage. It is this compressed carbon dioxide that could be used as a solvent in industrial processes.

Researchers in the United Kingdom investigated the effect of impurities found in carbon dioxide from power plants on a chemical reaction. They tested the supercritical carbon dioxide in a reaction at a modern industrial production facility. The facility does not use supercritical carbon dioxide because the high compression costs proved uneconomical.

In this work, none of the major impurities – nitrogen, water and carbon monoxide – posed insurmountable problems at the concentration likely to be found in power plant exhaust. Water and carbon monoxide did reduce the activity of the catalyst metal used to speed up the reaction. Increasing the temperature restored the catalyst’s activity.

This work is very relevant to industry and is a very promising first step toward reusing captured carbon dioxide. But, as the authors pointed out, it is only preliminary, and only one reaction was studied. Also, many impurities found in power plant carbon dioxide in very small quantities were not investigated.

Read more science at Environmental Health News.

 

Applying 21st century toxicology to green chemistry.

By Eddy Ball
October 2011

Scientists aiming to develop real-world solutions for problem chemicals gathered at a workshop on “Applying 21st Century Toxicology to Green Chemical and Material Design” Sept. 20-21, at the House of Sweden Event Center in Washington, D.C. The workshop was part of the National Academy of Sciences (NAS) ongoing series organized by the Committee on Emerging Science for Environmental Health Decisions sponsored by NIEHS. This workshop was unique in that it was co-hosted by the National Science and Technology Councils (NSTC) Committee on Environment, Natural Resources, and Sustainability (CENRS) Subcommittee on Toxics and Risks.

With more than 83,000 chemicals available for use in the U.S. today, there is rising concern about potential toxic properties these chemicals pose in relation to human health and the environment. This issue has given rise to the field of green chemistry — the science-based design of chemicals to minimize the use and generation of hazardous substances.

Visioning a green future

The workshop brought together chemists, toxicologists, and biologists to define common goals, identify knowledge gaps, and promote applied research aimed at expediting the application of new approaches to toxicology to the emerging field of green chemistry. As he opened the meeting, NIEHS Toxicology Liaison and co-chair of the NSTC Subcommittee on Toxics and Risks Christopher Weis, Ph.D., challenged participants to think of a future with safer chemicals and less need for regulation.

Paul Anastas, Ph.D., assistant administrator of the U.S. Environmental Protection Agency Office of Research and Development, who is often referred to as the father of green chemistry, then set the stage for the meeting’s three sessions with a presentation, titled “Vision of a Green Chemical Future.” Anastas told participants, “There are tremendous advantages — environmental, economic, and health-related — in implementing green chemistry into the design and production of the next generation of chemicals.”

The main focus of the sessions centered on identifying replacements for problematic chemicals and the emerging tools available for toxicology testing. Representatives from industry, academia, and government agencies discussed the utility of rapid assessment approaches in toxicology, including high-throughput biochemical screening, in vitro cellular approaches, and rapid assessments using aquatic organisms.

Putting the plan to action

During session three, Thaddeus Schug, Ph.D., a postdoctoral fellow on detail to the NIEHS Division of Extramural Research and Training, highlighted a collaborative project that is constructing a protocol for chemists to flag endocrine disruptors early in chemical development. “The protocol is not regulatory,” Schug emphasized, “but a guide chemists can follow as they develop a chemical, to give them confidence as to whether the substance is or is not an endocrine disruptor.”

Thaddeus Schug, Ph.D.
“What we propose to do is put the fastest, cheapest testing up front, the computational modeling, followed by high throughput screening and the zebrafish models,” Schug explained. The first-tier testing would be followed up with more specific testing as a chemical moves farther along the developmental process. (Photo courtesy of Steve McCaw)

The project, which is sponsored by the groups Advancing Green Chemistry and Environmental Health Sciences, publisher of Environmental Health News, has come up with a tiered system.

“The idea is if chemists hit a positive early on, they would either go back to the drawing board, or if that positive was in a specific area, such as an estrogen receptor in a high throughput assay, they’d follow that up with more comprehensive assays,” Schug continued. “A hit anywhere along the tiered system means chemists need to pull back, reanalyze, or throw the chemical out.”

The protocol is voluntary, explained Bruce Blumberg, Ph.D., a professor of developmental and cell biology at the University of California, Irvine. “We suggest this if you want to screen for endocrine activity in your chemicals and make them more green – this is the way we think you should do it. We’re providing an alternative approach interested parties can use to make the best chemicals they can,” he said.

Richard Denison, Ph.D., senior scientist at Environmental Defense Fund, welcomed the protocol’s development, saying, “It really flips the concept of tiered testing around.” Usually in tiered testing, a chemical only advances to the next level of testing if it is flagged for an effect at an earlier level. “[That] puts a huge question mark around the extent to which false negatives are being missed,” Denison added.

Christopher Weis, Ph.D.
“Dream big of a future in which green chemistry will move into the marketplace to the extent that this science will ultimately short-circuit the need for regulation,” Weis told workshop participants. “This will allow us to think ahead about potential chemical effects, rather than respond to problems that arise after chemicals are introduced.” (Photo courtesy of Steve McCaw)

Include key green chemistry ideas when covering polymer science.

Posted by Wim Thielemans, Sep 28, 2011

A recent article in Chemical & Engineering News leaves out key points reporters should include when explaining the pitfalls for new polymers vying for market share.

A cover story in Chemical & Engineering News describes a variety of new polymers – commonly called plastics – that are vying for current market share in a crowded field. Author Alexander H. Tullo focuses on how companies are avoiding the pitfalls of previous attempts to break into markets dominated by the long-used polymers – such as polyethylene, polypropylene and nylon – that were developed prior to 1960.

The long article covers a lot of ground but misses some important aspects of materials science and green chemistry, which should also be considered.

Tullo expertly describes a variety of polymers with varying chemical properties. He clearly states the market potential of these polymers, emphasizing their improved properties. While this is obviously important, cost  – especially for bulk polymer applications – is not mentioned. Many new polymers tend to be more expensive than those currently used. Existing polymers tend to be cheaper because of economies of scale – larger volumes are cheaper to produce. Yet, producing large amounts at a reasonable price is a major hurdle for new polymers in trying to find inroads to these low-cost and high-volume applications.

The author did not specifically mention which markets would be the most receptive to the new polymers. Yet, the examples clearly show that niche, high-value and new-technology applications present the most important inroads. This is especially true where existing polymers do not do a perfect job and improvement is easily achieved.

Some final hints may help journalists to collect and report more detailed information on the environmental impact of materials. As an example, the environmental benefit of the Novomer polymer mentioned in the article is extraordinary. It is a real feat to make a polymer with 40 percent of its total weight derived from carbon dioxide (CO2), which is removed from the atmosphere to make the polymer.

Reporters, though, need to dig deeper and ask about key points to help readers better understand a product’s overall impact. For example, if a point is made about removing CO2 from the atmosphere, ask how much material needs to be made to sequester the CO2 from a single power plant’s emissions, whether there is a market for all the material and whether the chemical reaction to make the polymer could cope with the quantities and required reaction rates to keep up with CO2 supply.

If environmental benefits are mentioned, ask for life cycle analysis results. Life cycle analyses describe the start-to-finish environmental effects from making a material to disposing of the finished product. The analysis results will make it clear if a real environmental benefit exists. Also, ask whether the preparation of the material conforms to the Principles of Green Chemistry. In the case of the Novomer polymer, the use of ethylene oxide – a well-known neurotoxin – in the polymer preparation would certainly raise questions about its environmental credentials.

The article is very interesting and an enjoyable read, but is at times rather narrowly focused. I would have liked the author to more broadly question the reasons why new polymers have such a difficult time entering and expanding into the marketplace.

Read more science at Environmental Health News.

 

Scientists constructing tool for chemists to flag endocrine disruptors early in chemical development.

The reporter got the attribution for our project wrong (NIEHS is not financially supporting this work, but is supporting it in kind. AGC and sister organization, Environmental Health Sciences, are funded to do the project). Still though: we are glad people are interested.

Pesticide and Toxic Chemical News
Friday September 23 2011

A group of biologists and green chemists, supported by the extramural research division of the National Institute of Environmental Health Sciences, is developing a protocol for chemists to use to determine if the chemical they are developing is an endocrine disruptor.

Thaddeus Schug, who manages a portfolio of grants in the NIEHS Cellular, Organs and Systems Pathobiology Branch, highlighted the project during a panel discussion on practical approaches to integrating rapid testing into the chemical design process. The discussion took place Sept. 21, the second day of a workshop, “Applying 21st Century Toxicology to Green Chemical and Material Design,” which was sponsored by the National Academies’ Standing Committee on Use of Emerging Science for Environmental Health Decisions. Schug says the group has been working for the last year on developing a protocol, and the guiding principles behind it, to determine whether a chemical under development is toxic, and how and where testing should be performed.

“We focus on endocrine disruption, but our guiding principles and protocol could be developed to capture all forms of toxicity,” he said. The protocol is not regulatory, Schug said, but a guide chemists can follow – as they develop a chemical – to give them confidence as to whether the substance is or is not an endocrine disruptor.

The group, which includes non-governmental organizations, academics and green chemistry leaders, has come up with a tiered system. “What we propose to do is put the fastest, cheapest testing up front – the computational modeling, followed by high throughput screening and the zebrafish models,” Schug said. That would be followed up with more specific testing as a chemical moves further along the development process.

“The idea is if a chemist hits a positive early on, he’d either go back to the drawing board, or if that positive was in a specific area [i.e. an estrogen receptor in a high throughput assay], he’d follow that up with more comprehensive assays,” Schug said. “A hit anywhere along the tiered system” means the chemist has to pull back, reanalyze or throw the chemical out, he said.
“The idea is to do the fastest, cheapest test early on, so the chemist can weed out those problem chemicals early on in development so it’s not a costly procedure,” Schug said.

The idea of the protocol “arose from a great sense of frustration” in the endocrine disruptor community, Bruce Blumberg, a professor of developmental and cell biology at the University of California, Irvine who also is working on the project, said during the panel discussion. This frustration stemmed from “hearing things like, ‘Well, you can’t test for endocrine disruptors,’ which the American Chemistry Council says,” Blumberg noted. “We know very well how to test for endocrine disruptors, how to test for endocrine disruptor activities from in vitro all the way to animal studies,” he said. “So we said this is a gap that has to be filled, and we got together to fill that gap.”

The protocol is voluntary, Blumberg noted. “We suggest this if you want to screen for endocrine activity in your chemicals and make them more green – this is the way we think you should do it. We’re providing an alternative approach interested parties can use to make the best chemicals they can,” he said.

Richard Denison, senior scientist at Environmental Defense Fund, welcomed the protocol’s development, saying “it really flips the concept of tiered testing around.”
Usually in tiered testing, a chemical only advances to the next level of testing if it is flagged for an effect at an earlier level, “which puts a huge question mark around the extent to which false negatives are being missed.”

But in the case of the protocol, “you’re advancing things that don’t raise red flags to the next level [of testing], increasing the confidence that you didn’t miss anything,” Denison said. “I think that’s a really intriguing approach.”
(Read full article here.)
– Liz Buckley

Shortcut converts common cellulose into useable parts.

Synopsis by Wim Thielemans, Sep 23, 2011

Long, J, B Guo, X Li, Y Jiang, F Wang, SC Tsang, L Wang and KMK Yu. 2011. One step catalytic conversion of cellulose to sustainable chemicals utilizing cooperative ionic liquid pairs. Green Chemistry http://dx.doi.org/10.1039/c1gc15597k.

A new one-step process blends a pair of specially selected solvents with cellulose, overcoming a big hurdle in the race to use the plant-based material as a reliable source of chemicals and fuels.

Pairing up a unique blend of specialized chemical solvents with plant cellulose has solved a looming problem for chemists grappling to find an efficient method to break apart naturally abundant cellulose.

The one-step process uses two ionic liquids to break cellulose down into its smaller chemical pieces and convert these pieces into useful chemicals. This is an important feat since cellulose is targeted as an alternative source for the chemicals and fuels currently derived from fossil fuels.

The results show for the first time that combinations of ionic liquids can be very useful in guiding more efficient chemical reactions that create less waste and more product. The findings are interesting because they show it is possible to combine several processing steps just by choosing the correct mixture of solvents.

Cellulose is a major part of plant cells and is the most abundant renewable material on Earth. Every year, plants, algae and some bacteria produce in excess of an estimated 100 billion metric tons. Cellulose is not a food and is a waste product of agriculture.

An enormous research effort is underway to understand how to use cellulose as a starting material for biofuel and chemical production in order to replace crude oil. In this process, cellulose – a long chain of identical chemical units – needs to be separated into the individual units.

The key challenge to convert cellulose into chemicals is its poor solubility – that is, it does not break up easily in liquids. Chemical reactions, though, require close contact between all the parts to work well. In 2002, researchers reported that some ionic liquids were very good at dissolving cellulose.

Ionic liquids are salts – a designation for chemicals made up of both a positively and a negatively charged component– that are liquid at low temperatures, unlike common salts such as table salt. Bulky positive and negative groups that make up the ionic salts hinder their packing into a solid crystal. Thus, they stay liquid to much lower temperatures – even room temperature.

In this work, Chinese researchers used a mixture of two ionic liquids. The first was chosen to dissolve cellulose. The second was chosen because it increases cellulose breakdown into its individual units, and further, into useful chemicals.

Under the right conditions, all the cellulose was broken down. The reaction products were also removed from the ionic liquid mixture by simply adding an insoluble solvent such as methanol or hexane. While there were a variety of different reaction products, up to 48.5 percent of the cellulose could be converted to a single product: 2-(diethoxymethyl)furan. This chemical, in turn, can be easily converted into a variety of other products useful for the chemical and pharmaceutical industries.

The choice of the solvent to extract the reaction products from the ionic liquid also allows researchers to select the reaction products that are recovered.

The ionic liquid mixtures were also reused. No real difference in performance and composition was noticed over 10 repeated reactions.

The researchers chose to dissolve cellulose first followed by a reaction to convert cellulose into smaller, more useful products. However, the results suggest the system is versatile and – depending on which ionic liquids are selected – could be extended to several reactions in a row. Ionic liquids will certainly hold some surprises in the future.

Read more science at Environmental Health News.

 

Nano research leads to a greener lubricating oil.

Synopsis by Wim Thielemans, Sep 15, 2011

Majano, G, E-P Ng, L Lakiss and S Mintova, 2011. Nanosized molecular sieves utilized as an environmentally friendly alternative to antioxidants for lubricant oilsGreen Chemistry http://dx.doi.org/10.1039/c1gc15367f.

An environmentally-friendly, sieve-like nanomaterial can reduce the chemical fallout from the breakdown of lubricants better than the chemical additives now used.

Looking to solve an old problem in a new way, green chemists find that a special porous material can better reduce levels of dangerous breakdown byproducts in oil lubricants than the long-used but harmful chemicals now added. The team of researchers report their findings about the material – called zeolites – in a recent issue of Green Chemistry.

Lubricant oils reduce friction between moving parts in machines and motors in every part of society, including factory conveyor belts, cars and sewing machines. Synthetic mineral oils are used most often because they are more stable than other types. About 32 million tons of the lubricant oils leak and enter the environment every year.

To reduce human health impacts and meet new European regulatory standards, chemists are trying to find ways to make the oils both functional and environmentally benign.

One big problem with lubricants is they break down and form byproducts when exposed to oxygen – a process known as oxidation. Oxidation generates water, reactive alcohols and acids that increase corrosion and rust, thicken the lubricant, form sludge and sediment, break down the oil and create foam.

Chemical additives prevent or reduce the oxidative reactions. Unfortunately, most additives are dangerous and can impact human health and the environment. Some also affect the machine’s function, such as deactivating the catalyst converters in cars.

In this work, researchers from France, Belgium and Malaysia tested how a highly porous inorganic nanomaterial called zeolites absorb the initial oxidation products in an effort to reduce the harmful chemical byproducts that form. They did not try to stop oxidation like the current crop of chemical additives do. In theory, since oxidative reactions naturally speed up over time, removing the reaction products would reduce further oxidation, slow the process and create less harmful byproduct.

One of the three zeolites compared in the study worked surprisingly well. The researchers found the zeolite cleans up the process in two ways. First, it slowed the inherent oxidation reactions and reduced the amount of chemical byproduct produced. Second, it also absorbed the byproducts that formed. In the end, very little sludge was produced.

The zeolites used have no known adverse environmental effects and can even work together with existing oxidation-preventing chemical additives. The zeolites – when combined with perhaps a next generation of more benign additives – would then give added protection.

Future laboratory studies will need to test the performance of the numerous other zeolites available. From there, they must be tested and assessed in a real working environment. Even though this is not the final word on the technology, it looks to be very promising.

Read more science at Environmental Health News.

gossip computer

Apply for 2013 Science Communication Fellowship

Open to post doctoral fellows and junior faculty with active research programs related to Green Chemistry. Advancing Green Chemistry in partnership with Environmental Health Sciences is offering a Science Communication Fellowship designed to teach and improve scientist’s communication and outreach skills early in their professional careers. Fellows practice writing, presenting and publishing accessible summaries of important new research results.

Nominations are being accepted now for the competitive, one-year fellowship that will further enhance the researcher’s media communication skills and offer a strong peer network. Fellowship training provides participants the tools with which to communicate Green Chemistry research to media, policy makers and the public. The program emphasizes US based media.

***Apply for the 2013 Science Communication Fellowship***

NIEHS scientists join forces with green chemists.

By Thaddeus Schug
April 2011

A representative diagram of the draft screening protocol  unveiled at the meeting
A representative diagram of the draft screening protocol unveiled at the meeting. The protocol is designed in a tiered approach, with rapid and cost effective screens conducted in the early phases and more extensive testing toward the end. (Slide courtesy of Pete Myers)

NIEHS/NTP scientists joined forces with leaders in the field of green chemistry in what may turn out to be a groundbreaking meeting, “Green Chemistry and Environmental Health Sciences — Designing Endocrine Disruption Out of the Next Generation of Materials,” held March 21-23 in Sausalito, Calif.

The challenges facing scientists trying to design such new materials are daunting. Say a chemist has developed a compound that he or she believes could be a replacement for bisphenol A (BPA). How will the scientist determine if the molecule is safer to human health and the environment? What testing will need to be done and what will guide scientists through this process?

The goals of the meeting in Sausalito were ambitious — to develop a consensus statement on the principles that guide the science needed to assess risks of potential endocrine disruptors, and to develop a reliable and rational testing protocol to aid chemists as they develop and bring the next generation of chemicals into the marketplace.

The intersection of green chemistry and environmental health science

Karen O’Brien, Ph.D., from Advancing Green Chemistry (AGC) and Pete Myers, Ph.D., of Environmental Health Sciences (EHS), welcomed participants to the event, which brought together an equal mix of biologists and chemists. Representatives from NIEHS and NTP included Division of Extramural Research and Training (DERT) program administrator Jerry Heindel, Ph.D., and Kristina Thayer, Ph.D., director of the NTP Center for the Evaluation of Risks to Human Reproduction (CERHR).

Following a social ice-breaking exercise on the evening of March 21, the first full day of the meeting opened with presentations from Terry Collins, Ph.D., the Teresa Heinz Professor of Green Chemistry at Carnegie Mellon University, and John Warner, Ph.D., president and founder of the Warner Babcock Institute for Green Chemistry.

Both Collins and Warner stressed the need for fundamental changes in the way that scientists design new chemicals and the process of bringing them into the marketplace. “We must also pay close attention to the environmental impact and the effects on human health posed by these chemicals, and for those reasons chemists need to work hand-in-hand with biologists,” said Warner. He also stressed that chemists generally have no background in toxicology, but that they need to be able to test the chemicals being developed for endocrine activity and to do it early on in the product development process.

Designing a chemical screening protocol

The remainder of the day was divided into discussion sessions covering each phase of a newly developed screening model, designed by a science advisory board formed by meeting organizers that met monthly, via teleconference, for six months prior to the workshop. The protocol is geared towards identifying a wide-range of endocrine-active chemicals, such as atrazine, BPA, brominated flame retardants, organotins, perchlorates, and phthalates. The Board conducted  interviews with scientists with expertise in specific areas of toxicology, endocrine disruption, and assay development.

The testing paradigm proposed involves a five-tiered approach, starting with the fastest and cheapest assays and working through more specialized tests to determine whether a new chemical has endocrine disrupting characteristics. The initial two phases rely on predictive computer modeling and high-throughput screening to quickly weed out problem chemicals. These tests are followed by more specific in vitro cell-based screening assays with a mind to refining, reducing, and replacing animal testing as much as possible.

The final two phases involve use of fish, amphibian, and mammalian in vivo modeling systems. Overall, the protocol is intended to help green chemists establish a high degree of confidence that the replacements they are developing are unlikely to be harmful to humans or the environment.

The next steps

The meeting wrapped up with discussion on how to proceed with development of the testing protocol as well as plans for implementation. The advisory board plans to use input from the meeting to develop and publish a white paper outlining guidelines that chemists can use to assess the quality of protocols and tests used to assess endocrine disruption.

(Thaddeus Schug, Ph.D., is a postdoctoral research fellow currently on detail as a program analyst in the NIEHS Division of Extramural Research and Training. He was part of the NIEHS/NTP delegation and a presenter at the meeting.)

 

Left to right, Collins, Heindel, and Warner mix ingredients  for a batch of salmon tartare.
Left to right, Collins, Heindel, and Warner mix ingredients for a batch of salmon tartare.  The cooking exercise was used as an ice-breaking event to demonstrate how environmental health scientists and chemists can work together to solve complex issues. (Photo courtesy of Pete Myers)

Laura Vandenberg, Ph.D., left, contributes to the discussion  on assay development, as Tom Zoeller, Ph.D., center, and Wim Thielemans, Ph.D.,  look on.
Laura Vandenberg, Ph.D., left, contributes to the discussion on assay development, as Tom Zoeller, Ph.D., center, and Wim Thielemans, Ph.D., look on. Vandenberg, a postdoctoral fellow at Tufts University, studies the developmental effects of endocrine disrupting chemicals. (Photo courtesy of Pete Myers)

Left to right, Bruce Blumberg, Ph.D., Thayer, and Andreas  Kortenkamp, Ph.D., served as panel members for a discussion on in vitro screening assays.
Left to right, Bruce Blumberg, Ph.D., Thayer, and Andreas Kortenkamp, Ph.D., served as panel members for a discussion on in vitro screening assays. (Photo courtesy of Pete Myers)

A group photo of the meeting attendees.
A group photo of the meeting attendees. The meeting was held at the Cavallo Point Lodge, which sits adjacent to the Golden Gate Bridge. (Photo courtesy of Pete Myers)

NIEHS  grantees Andrea Gore, Ph.D., left, and Frederick vom Saal, Ph.D., were among  panel members for the discussion on in  vivo assays.
NIEHS grantees Andrea Gore, Ph.D., left, and Frederick vom Saal, Ph.D., were among panel members for the discussion on in vivo assays. Both Gore and vom Saal are members of  the project’s scientific advisory board. (Photo courtesy of Pete Myers)

 

Emerging Environmental Health Science in Green Chemistry

NIEHS Senior Advisor for Public Health John Balbus, M.D., attended the inaugural symposium March 24 for the new University of California, Berkeley Center for Green Chemistry, entitled “Green Chemistry: Collaborative Approaches and New Solutions.” Balbus’ talk, “Incorporating Emerging Environmental Health Science in Green Chemistry,” outlined some of the challenges of applying 21st century science to protect public health.

  • How do we harness the potential of unlocking the genome?
  • Can we more accurately predict which chemicals are likely to cause harm?
  • How do we implement our understanding of susceptibility and non-chemical stressors to enhance human health?
  • How can we better incorporate new methods and technologies into science policy?

Balbus proposed that the newly developed Tox21 (http://ntp.niehs.nih.gov/index.cfm?objectid=06002ADB-F1F6-975E-73B25B4E3F2A41CB), an interagency high throughput screening initiative, is aiming to meet many of these challenges and could be a valuable tool for green chemists. Demonstrating its utility in screening chemicals for disruptions in insulin signaling, Balbus concluded, “Advancements in programs such as Tox21 will eventually allow us to accurately predict how chemicals will impact human health before they are brought into the marketplace.”

Novel ‘Green’ Chemical Endocrine Screening Protocol Looks Beyond EPA’s

Inside EPA: Risk Policy Report – 07/12/2011
By Jenny Hopkinson

A group of private and government scientists is moving closer to completing a testing protocol for determining whether new “green” chemicals entering the market are safer than those they are intended to replace and do not pose endocrine disruption risks, an effort that extends beyond EPA’s screening program, which focuses on existing chemicals.

Advancing Green Chemistry (AGC), the non-profit group leading the efforts, has joined with National Institute of Environmental Health Sciences (NIEHS), Environmental Health Sciences, Inc and other private sector groups, to develop a five-tiered testing protocol that will eventually be available free to chemical producers to determine whether their products may disrupt human endocrine systems, an outcome that has been linked to a slew of health problems including obesity and breast cancer.

An AGC source says the protocol is close to being submitted for peer review and developers hope it will be completed in about another year.

The protocol is designed to address concerns that newly developed green chemicals — which are intended to be safer alternatives than existing substances — may not be much better for the endocrine system, which regulates the body’s hormones, than the existing chemicals they are being created to replace.

While EPA is required by law to test a slew of existing chemicals under its endocrine disruptor screening program (EDSP), so far the agency has been “stuck” in what it can get done and has been struggling for almost two decades, the AGC source says.

Delays with the EPA program have long been a concern. For example, former House Rules Committee Chairman Louise Slaughter (D-NY) last year pushed legislation that would have created a new endocrine screening program at NIEHS, in part because EPA had been slow to establish its program. “While EPA does have the EDSP they’ve been more focused on toxics and only in the past few years focused on endocrine disruption,” her spokeswoman said (Risk Policy Report, Dec. 22, 2009).

Similarly, the AGC source says EPA is “snarled up in the morass of trying to regulate existing chemicals, and that hamstrings people.” Testing for endocrine disrupting effects “is something the government should be doing, but it just doesn’t seem to be something that’s happening,” the source says.

The source puts the blame on industry for the delays in EPA’s program. “There’s a lot of vested interest in the chemicals on the market” by their manufacturers, and that is slowing down the process, the source says. So far the agency “hasn’t been able to sort that out.” Rather than get bogged down in attempts for regulation of the chemicals, “we are trying to just look forward,” the source says.

But that is not to say that EPA hasn’t shown interest in the protocol. Paul Anastas, head of the Office of Research and Development, has been involved with developing the system, although the source says while he has been “constructive and supportive,” there has been no indication that EPA will adopt the methods. “But if they want to take over our project, great I think that would be better for all of us,” the source adds. “This should just be the way we test chemicals, period.”

A second source, however, argues that EPA’s programs aren’t capable of looking at such sensitive effects of chemicals. “Unfortunately there are people still working in the lab in EPA . . . who will say none of this work has any value,” the source continues. “They are stuck with toxicologists who are still doing old school toxicology.”

As a result, AGC, about a year ago, brought together a group of chemists, toxicologists and other government and private scientists to examine what the source describes as a “burgeoning wave” of new science on endocrine disruption with the goal of developing a tool for chemical makers to ensure in the development process that a chemical will not have effects on hormones.

The result is a five-tiered protocol that begins with what the source described as “quick and easy” Quantitative structure-activity relationship (QSAR) modeling and looking at a chemical’s structure, followed by in vitro high-throughput screening assays, validated and specialized cell-based assays, amphibian and fish tests, with the final tier being mammalian testing.

While chemical producers can run a new substance through as many or as few tiers as they choose, if a chemical passes through all the tiers, then it is quite likely to be safe, said Thaddeus Schung, a postdoctoral research fellow with NIEHS, speaking at the American Chemistry Society’s 15th Annual Green Chemistry and Engineering Conference in Washington, DC, June 22.

Schung said that the system aims to be a logical, consensus based tool to determine endocrine activity based on sound science. “Were trying to use this brain power here to come up with a sensible effort to . . . predict chemical toxicity.” Our hope, Schung said, is to “kick some of these chemicals out of production and make way for some new chemicals that are being developed by green chemistry.”

The AGC source echoes this, saying the protocol will provide an important new tool for chemical producers. As chemists develop these new materials “it’s really hard for them to know whether or not what they’ve designed has the potential to be an endocrine disruptor.”

“Green chemists are being asked to design the next generation of benign chemicals and they don’t have the tools to do it,” the source continues, adding that chemists are not toxicologists. “This is the new design criteria — you want to make chemicals that don’t act like hormones and don’t rewire people’s systems.”

And another source says that given the public backlash on products containing such endocrine disrupting chemicals such as bisphenol A (BPA), “industry is staying ahead of this now,” the source says. “They realize that this is the way we have to go.” – Jenny Hopkinson