Goodbye Endocrine Disruption!

By Shivanthi Sriskandha, Member-at-Large for the GCI

A recent study published in the Royal Society of Chemistry journal, Green Chemistry, has aimed to bridge the gap between chemists and toxicologists in the design of safer, sustainable chemical products. The paper is authored by 23 scientists in the fields of green chemistry, biology, and environmental health science, and proposes a protocol to effectively develop compounds that will not cause endocrine disruption.

Oral contraceptives contain a combination of estrogen and progestogen, known EDCs that have implications on fish and other wildlife.

Endocrine disruption occurs when an agent or mixture of chemicals interferes with any aspect of hormone action. Common endocrine-disrupting chemicals (EDCs) include BPA, DDT, flame retardants, and phthalate-containing products. As such, the primary concern is exposure to these chemicals in consumer products. Research has now shown that EDCs can affect human metabolism, liver, and bone function as well as have an impact on diabetes, obesity, infertility, and learning disorders.

Currently, environmental performance and sustainability are not taken into account when designing new chemicals, or at least not emphasized enough. Furthermore, chemists have a limited knowledge of toxicology and therefore aren’t trained to evaluate toxicity risks. For these reasons, the Tiered Protocol for Endocrine Disruption, or TiPED, system was invented to guide chemists towards the design of safer materials.

Pesticides and herbicides used for agricultural and domestic purposes are common sources of EDCs.

The 5-tiered TiPED system combines principles in green chemistry with new methods of toxicology to form a comprehensive system that will evaluate a new chemical’s toxicity. The system is designed so that the user has the ability to enter the process at any stage in order to best meet the user’s needs. In each tier, a pass-fail grade is given to the chemical in question. If it passes, it is allowed to move onto the next stage for further testing. If it fails, it must go back to the drawing board to be reassessed. Since the current protocol cannot detect all possible mechanisms of endocrine disruption (an area of science that is still in progress), updates to the protocol will be made on the peer-reviewed TiPED website as they are developed.

The proposed tiered test for endocrine disruption, TiPED.[1]

Here’s how the Tiers work:

• Tier 1: Computational approaches that can assess the chemical compound by searching existing databases for known EDCs and by predicting endocrine-disrupting behaviour using computer models.
• Tier 2: Cell-based assays that directly test a chemical’s ability to interact with and affect the activity of targeted proteins, hormone receptors, and genes.
• Tier 3: Assesses the activity of a test chemical on an endocrine-signaling pathway that may lead to cell division, differentiation or death, or to endocrine-mediated processes.
• Tier 4: Determines chemical impacts on fish and amphibian reproductive cycles, development and behaviour.
• Tier 5: Mammalian testing to mimic responses in humans.

Overall, consumer awareness of the harm in commercial products is leading to the development of safer chemicals and greater collaboration between various scientific disciplines to make our world a healthier place.

For further information, please see the companion website: www.TiPEDinfo.com where you can gain access to the paper and consult the formal protocol on the TiPED system.

References:

[1] T. T. Schug et al., “Designing endocrine disruption out of the next generation of chemicals”, Green Chem. 2013, 15, 181-198.

Chemicals from Food Waste Biomass

By Shivanthi Sriskandha, Member-at-Large for the GCI

It is common knowledge that we are in desperate need of a means to both reduce environmental waste and develop alternative renewable resources. The following papers by Roger A. Sheldon and James H. Clark, both published in Green Chemistry, outline research on the production of chemicals from food supply chain waste (FSCW) biomass.[1, 2] A fundamental aspect of green chemistry is preventing pollution rather than mitigating waste. This involves substituting non-renewable fossil fuels including crude oil, coal, and natural gas.

Components of food supply chain waste and how they can be used in consumer products. [2]

Renewable biomass has been seen as a potential sustainable resource for the manufacture of chemicals and liquid fuels. While first-generation biomass feedstocks (maize and edible oil seeds) may compete with food production, second-generation bio-based fuels use wasted biomass. These waste products include sugar cane bagasse, corn stover, rice husks, and orange peel. The most sustainable means of achieving this is to create value from this unavoidable waste biomass generated during the production of edible crops. Thus, FSCW can serve as a resource for the production of bulk chemicals that are made on large scales to satisfy the global market.

The estimated global production of biomass amounts to approximately 10¹¹ tonnes per annum, of which only 3% is cultivated, harvested, and used in food and non-food applications.[1] By using specific chemical syntheses to process this biomass waste into commercial chemicals we could replace the vast quantities of chemicals currently produced from petroleum hydrocarbons in traditional oil refineries. Thus, the carbon footprint of chemicals and liquid fuels can be reduced by switching to renewable FSCW as a feedstock.

James H. Clark has found a way to turn orange peel waste into high-value chemicals. [2]

Citrus fruits are a promising biomass of which approximately 82 million tons were produced in 2010-2011.[2] The peel of citrus fruits generated by the juicing and canning industry have the potential to be used as a biorefinery raw material. In his paper, J. H. Clark describes the Orange Peel Exploitation Company project that produces large quantities of known marketable and high-value chemicals such as D-limonene, pectin, and flavonoids from waste orange peel using a low-temperature hydrothermal microwave process.

Ultimately, by using all components of food supply chain waste we are protecting the environment in more ways than one. In these two papers, R. A. Sheldon and J. H. Clark certainly give very convincing arguments as to the production and use of biomass resources. But is this really a feasible alternative? What volume of FCSW would be required to maintain the current production of commodity chemicals? What do you think? Could biomass be the future of chemical production?

References:

[1] R. A. Sheldon, “Green and sustainable manufacture of chemicals from biomass: state of the art”, Green Chem. 2014, 16, 950-963.

[2] L. A. Pfaltzgraff, M. De bruyn, E. C. Cooper, V. Budarin, and J. H. Clark, “Food waste biomass: a resource for high-value chemicals”, Green Chem. 2013, 15, 307-314.