There are about 4 million different chemical substances that are produced and/or separated worldwide. About 30,000 chemical substances are in permanent use with masses exceeding more than 10 tonnes per year for each substance. Almost every economical branch in Europe is influenced by chemical pollution. Professional illnesses found in the workforce or food chain contamination are a few examples of the numerous issues arising from the use of chemicals. Another example is the use of chemicals for agricultural purposes. These chemicals have been increasing the risks of chronicle illness development among humans even though these same chemicals are useful for general production.
Costs to resolve health damage and environmental problems are extremely high at the moment for national economies and for the world as a whole. A respectable review about the costs of environmental damage and the benefits of sustainable chemistry can be found in the current United Nations Environment Program (UNEP) report: Global Chemicals Outlook. Scientists have proven that promoting a preventative strategy can help reduce the hazardous impacts on humans and the environment, while being evidently advantageous for various economies as well. The path of increasing precaution and reducing destruction is an alternative approach to properly organise and control the use of chemical substances. This concept is referred to as “Green” or “Sustainable Chemistry”. The Chemical Outlook describes it as following: “Green Chemistry is not a new branch of science, but more a new philosophical approach that underpins all of chemistry and has technological, environmental and societal goals”.
Sustainable Chemistry tries to improve efficiency while simultaneously staying safe and environmentally friendly. It seeks to discover new substances, searches for the best practices and production processes to increase performance, optimises the use of resources, reduces the generation of wastes and protects human health and the environment. Sustainable Chemistry protects employees and seeks for innovative strategies in order to stimulate the economy. Sustainability, human health and environmental protection, competitiveness and innovative progress are the basic links of the Sustainable Chemistry concept.
Sustainable Chemistry offers many advantages to the industry: better competitiveness, better modernity, better reputation, and better awareness of sustainable products addressed by consumers.
Principles of Green Chemistry
The twelve Principles of Green Chemistry were drafted by Dr. Paul Anastas and Dr. John Warner. Listed below is the current version modified by the United Nations Environment Programme (UNEP) in The Global Chemical Outlook 2013:
- Prevent waste: Design chemical syntheses to prevent waste, leaving no waste to treat or clean up.
- Design safer chemicals and products: Design chemical products to be fully effective, yet have little or no toxicity.
- Design less hazardous chemical syntheses: Design syntheses to use and generate substances with little or no toxicity to humans and/or the environment.
- Use renewable feedstocks: Use raw materials and feedstocks that are renewable rather than depleting. Renewable feedstocks are often made from agricultural products or are the wastes of other processes; depleting feedstocks are made from fossil fuels (petroleum, natural gas, or coal) or are mined.
- Use catalysts, not stoichiometric reagents: Minimize waste by using catalytic reactions. Catalysts are used in small amounts and can carry out a single reaction many times. They are preferable to stoichiometric reagents which are used in excess and work only once.
- Avoid chemical derivatives: Avoid using blocking groups, protection groups, or any temporary modifications if possible. Derivatives use additional reagents and generate waste.
- Maximize atom economy: Design syntheses so that the final product contains the maximum proportion of the starting materials. There should be few, if any, wasted atoms.
- Use safer solvents and reaction conditions: Avoid using solvents, separation agents, or other auxiliary chemicals. If these chemicals are necessary, use innocuous chemicals.
- Increase energy efficiency: Run chemical reactions at ambient temperature and pressure whenever possible.
- Design chemicals and products to degrade after use: Design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment.
- Analyse using real-time to prevent pollution: Include in-process real-time monitoring and control during syntheses to minimize or eliminate the formation of byproducts.
- Minimize the potential for accidents: Design chemicals and their forms (solid, liquid, or gas) to minimize the potential for chemical accidents including explosions, fires, and unwanted releases into the environment.
Dimensions of Sustainable Chemistry
The idea of Sustainable Chemistry is easier to understand when looking at its various dimensions:
Hazardousness for Health and Environment
It is important to distinguish between the hazards and risks of chemical products. A “hazard” is understood as a potential damaging characteristic of a chemical, while a “risk” is the probability of exposure to a hazard under specific conditions or scenarios.
The compliance of all environmental laws for the production of chemicals is logically the minimum requirement for Green Chemistry. This basic rule can vary in different countries, especially in developing and developed countries due to differentiating laws. Currently, industrial emissions from production processes aren’t as much of a problem for industrial countries as opposed to the developing world because of these developed countries’ relatively advanced environmental laws. Much more important are the emissions from the manufactured and completed products. The risk analyses and the exposure management (the exposure reduction through organisational and technical management) are therefore more significant now. The risks can be drastically reduced through the advancement of information, education and technical expertise. The appropriate communication and the proper use of basic rules for the handling of chemicals is another basic requirement for the sustainable development within the chemical sector. The risk calculation is the unsatisfactory fact of the existing situation. The risks are hereby reduced but not completely avoidable. The concept of Sustainable Chemistry aims to reduce the production and use of hazardous substances, while promoting the development of better, less dangerous chemicals (benign by design).
However, there are some structural problems: chemical diversity and operationalization. The chemical market is large and numerous. There is no single definition for the hazardousness of chemicals. Substances can be dangerous in many different ways: hazardous for humans and/or hazardous for the environment; both of which can be differentiated by various effects. Unfortunately, there is a lack of sufficient data about the available chemicals to evaluate and classify them. The proper way to classify and appropriately label chemicals is to use the international Globally Harmonised System (GHS). This system is mandatory in Europe. All producers are supposed to report their substances to the European Chemicals Agency (ECHA) by 2011.
The following table shows the hazardousness classification of the GHS. Special tests must be conducted for those categories. In some cases, the classifications are gradually differentiated (e.g. acute toxicity) while in others, they are just binary: yes/no (e.g. cancerogenicity).
GHS- categories for human health and the environment:
Human Health Criteria
- Acute Toxicity
- Skin Corrosion/Irritation
- Serious Eye Damage/Eye Irritation
- Respiratory or Skin Sensitization
- Germ Cell Mutagenicity
- Reproductive Toxicity
- Target Organ Systemic Toxicity – Single Exposure
- Target Organ Systemic Toxicity – Repeated Exposure
- Aspiration Toxicity
- Hazardous to the Aquatic Environment
- Acute Aquatic Toxicity
- Chronic Aquatic Toxicity
The disadvantage of these data is the fact that there are no independent tests. Producers need to evaluate their products themselves. There is still the possibility to compare the data for a definite product from different producers, but that is all.
A grouping approach is appropriate for deriving the definition of hazardousness. Firstly, it is important to check if a chemical is a “substance of very high concern'' (SVHC). That is the case for ''carcinogenic, mutagenic and/or reproductive toxicants” (CMR). The ''persistent, bio-accumulative and toxic'' (PBT) substances, the ''very persistent and very bio-accumulative'' (vPvB) substances, and the substances with hormone-like effects (the endocrine disruptors) are the priority substances of high concern.
According to the concept of Safe Operating Space for Humanity by J.Rockström et al. (2009), there are natural boundaries in our ecosystems which cannot be exceeded without damaging the environment. These so called “planetary boundaries” were defined on the basis of biodiversity loss, climate change, ozone depletion, biogeochemical (nitrogen and phosphorus), ocean acidification, land use, freshwater contamination, atmospheric aerosols and chemical pollution. It is still difficult to distinguish precise boundaries for the chemical sector due to the enormous amount of substances (approximately 100,000 chemicals including more than 4,000,000 substances). Nevertheless, the concept addresses Earth’s limited absorption capacity for chemical substances. It especially concerns the non-degradable persistent substances such as heavy metals. Scientists like Klaus Kümmerer emphasise the significance of (bio-) degradability in a product’s life cycle when it ends up in the environment. The primary goal for Sustainable Chemistry is that all substances and products can degrade fast, easily and completely turning into possibly pure substances. The products must be safe throughout their entire lifetime: when serving their purpose and during the end of their life cycle as soon as they reach any other environment: soil, sea water or living organisms.
The concept of Sustainable Chemistry is resource efficient. The whole accumulated consumption of energy and raw materials must be evaluated. The guideline VDI 4800 can be used as a suitable methodical approach. In guideline VDI 4800, resource efficiency is defined as a relationship between the benefit or result to the necessary input of resources.
Improved efficiency can be achieved when a product is produced using a smaller range of effort than before.
Sustainable Chemistry is searching for ways to reduce the loss of entropy. Entropy cannot be regained; it is the energy lost in an open system. Natural processes are effective and close to the thermodynamic balance, which is why the entropy loss is very small in nature. For example, recycling demands enormous efforts in order to regain valuable substances. The less material there is within a product, the more extensive it is to get the material back by recycling. Within a defined range, recycling can cease to be sustainable. The heterogeneity of mass flows restrains the recycling process (e.g. the substance diversity in modern plastic products). The entropic loss grows with the size and heterogeneity of the mass flows. Therefore, the retrievability of a substance from a compound or product is another criterion for Sustainable Chemistry. The products should be designed for possible retrievability.
Sufficiency can be defined as the reduction of resource consumption and the search for the appropriate extent. For example, it provides the question addressing what the social benefits of a chemical or the use of a product are. Many things that are produced, sold and consumed are necessary for satisfying human needs. But who determines what belongs to our needs and what does not? Is there a distinction between essential needs and exaggerated luxury? It is a difficult question. Nevertheless, it is vital to include the sufficiency-dimension or the societal benefit as an important part of Sustainable Chemistry.
Each of the five criteria previously mentioned can be highly important depending on the concrete case and the exact issue. Nevertheless, those criteria do not have the same meaning in the context of the international development. To evaluate the sustainability of the chemical sector in a given country, the main focus has to be on hazardousness, pollution limits and resource efficiency. Special [Öffnet internen Link im aktuellen Fenster] development-indexes can be used for that purpose.
Best Practice / Case Studies / Reports
- Global Chemicals Outlook II: From Legacies to Innovative Solutions
- Unleashing Green Chemistry and Engineering
- Strategic Innovation and Research Agenda. Innovation Priorities for EU and Global Challenges
- Chemicals safety in the value chain. How the European chemical industry manages safe use of chemicals
- Economic Features of Chemical Leasing
- Background: Sustainable Chemistry. Positions and Criteria from the German Federal Environment Agency