TABLE 53 Chemical Assessment Attributes

Priority human health criteria (known or suspected):

• carcinogenicity,

• endocrine disruption,

• mutagenicity (accidental and/or engineered),

• reproductive and developmental toxicity (teratogenicity).

Additional human health criteria:

• chronic toxicity,

• irritation of skin/mucous membranes,

• sensitization,

• other (e.g., skin penetration potential, flammability, etc.).

Ecological health criteria:

• bioaccumulation,

• climatic relevance,

• content of halogenated organic compounds,

• daphnia toxicity,

• heavy metal content,

• persistence/biodegradation,

• other (e.g., mobilization of metals, regulatory issues, toxicity to soil organisms, etc.).

Natural systems equilibrium criteria:

• global warming potential,

• ozone depletion potential.

of Governmental Industrial Hygienists, ACGIH; etc.), teratogens (National Toxicology Program, NTP), ozone-depleting substances (Section 602(b) of the Clean Air Act), and so on. Other data must be gathered from various standard test methods (aquatic toxicity [OPPTS Harmonized Guidelines; 850.1075 and 850.1400], biodegradability [OPPTS Harmonized Guidelines, 835.3500 and 835.3400], and so on) and others from credible scientific literature (fate in the natural environment, known biodegradation breakdown products, etc.). Some of the data are publicly available, while others must be obtained from raw material manufacturers at the request of the product manufacturers. Some are based on expert assessment, models, and evaluation of analogs.

For ease in communicating levels of potential health effects, color coding is used to designate whether or not the data exceed criteria for each attribute. For list-based data, a chemical either is or is not on a particular list, for example, the National Toxicology Program Report on Carcinogens. For attributes such as aquatic toxicity, data are evaluated and cut-off criteria limits are set. Red would indicate toxicity to fish based on LC50 <10mg/L. Yellow would indicate moderate aquatic toxicity to fish with LC50 between 10 and 100 mg/L. Green would indicate that based on test results, the chemical is considered relatively nontoxic to aquatic life at LC50 > 100 mg/L. A color coding of orange is used to indicate the absence of data.

The first step most companies and industries take on the path to cradle-to-cradle is to identify and move away from substances that are widely recognized as harmful. A number of companies have developed Restricted Substances Lists based both on regulatory requirements and design ideals to support their designers and purchasers in this commitment. This approach has resounding impacts up and down the supply chain.

In the cradle-to-cradle assessment process, criteria are prioritized. The "Priority Human Criteria" (known or suspected) include:

• carcinogenicity;

• endocrine disruption;

• mutagenicity (accidental and/or engineered);

• reproductive and developmental toxicity (teratogenicity).

If an ingredient is found to violate the Priority Criteria, then every effort is made to avoid its use. Criteria are also prioritized based on the type of product and exposure routes. For example, cleaning products are generally released to the air and/or sewerage system. In addition, there is opportunity for inhalation, and skin and eye exposure. Therefore, criteria such as biodegradability, aquatic toxicity, skin and eye irritation, chronic toxicity (asthma), and sensitization would be priority criteria in designing cleaning products.

At a second level of commitment, companies can select ingredients by comparing existing substances based on their human and environmental health and safety (EH&S) profiles. In order to do so, they will need full product ingredient disclosure for ingredient assessment, as outlined above. Challenges in comparing ingredients include trade-offs and lack of data. Sometimes ingredients will appear to be relatively equivalent with respect to EH&S criteria. Companies must decide what criteria are most important and relevant based on the product's intended use, fate, and exposure routes and determine which attributes best reflect the company's highest aspirations. Which attributes are more important to the company and its stakeholders? What is the best decision that can be made now, knowing that more information in the future will continue to inform decisions? This requires decision-making under uncertainty, but still pushes forward the intention to design using materials with the most favorable human and environmental health profiles. For example, the Port of Portland worked with their Janitorial Service provider to convert at least 65 percent inventory to environmentally preferable cleaning products (EPP). They chose products that were either already eco-labeled or distinguished via partnerships such as U.S. EPA's Design for the Environment Formulator Initiative, products screened via State, City or Federal environmentally preferable purchasing programs, or products for which full ingredient disclosure was obtained and ingredients were screened for carcinogens, endocrine disruptors, hazardous air pollutants, ozone-depleting chemicals, persistent, bioaccumulative, and toxic substances (PBTs), teratogens, and alkylphenol ethoxylates. The screening was also informed by the Indiana Relative Chemical Hazard Score (http://www. ecn.purdue.edu/CMTI/IRCHS/) and the Janitorial Products Pollution Prevention Project (http://www.wrppn.org/Janitorial/jp4.cfm).

In the end, the goal is to specify and use only the safest, healthiest chemicals and materials. This can involve the development of lists of preferable chemicals (what we call "P-lists") for use in specific applications. The development of P-lists is useful and practical within a company, as well as within and between industries, as many of the same raw materials are used by different manufacturers for different applications. For example, dyes and surfactants are used so broadly that the identification of positively assessed ingredients in these categories could support the use of more benign ingredients in multiple sectors. There is a need to share data and information on ingredients based on application and performance to support product design, especially because the chemical assessment work is resource intensive.

Where materials do not currently exist, there is a clear need for new green chemistries to fill the void. Criteria for designating green or positive chemicals must be defined along with associated predictive human and ecotoxicology tests and physical chemistry assessment in order to support sustainable product design. And of course, one cannot assume that a new chemical is benign when no negative data are available simply because it has not been thoroughly tested.

Figure 5.5 illustrates levels at which data are used and weighted to support organizations in optimizing chemicals and materials in their products and processes.

Green chemistry faces many challenges in the next decade as data related to physical-chemical properties, human and ecological toxicology are collected internationally, and new tools emerge for predicting toxicology. Tools used for drug design and new chemical review are being adapted for identifying potential human and environmental health concerns for chemical ingredients, prior to their use in formulated products. In addition, green chemistry must address the development of materials with fundamentally new properties, such as those derived from nanotechnology and processes using genetically modified organisms.

5.2.3.2 Designing for Cradle-to-Cradle Metabolisms. Along with analyzing and selecting chemicals and materials for favorable human and ecological health profiles, the practice of cradle-to-cradle design sets out to design products from beginning to end to circulate productively and safely in biological or technical metabolisms. The design process includes the treatment of value recovery potential and energy considerations. Design for cradle-to-cradle metabolisms begins with the

Screen known hazards

Choose preferable ingredients

Create green chemicals and P-llsts

MSDSs, regulatory and other lists of known hazards.

Relative chemical hazard Extensive assessment based data and client values. on test data, modeled data, literature reviews and expert judgment.

Full ingredient disclosure.

Criteria for green chemicals based on application.

Figure 5.5. Applications and information needs for assessing human and environmental health.

identification of which metabolism, biological or technical, is appropriate for the product under design. Evaluation of the value recovery potential of a material is based on the following considerations:

• Is it technically feasible to recycle the material? What is the nature of the recycling process (chemical, mechanical)?

• Is the material biodegradable and potentially beneficial when discharged to environmental media or to an organic recovery system such as anaerobic digestion or composting?

• Does a recycling or organic recovery infrastructure exist for the material?

• What is the resulting quality of the recycled material or biodegraded nutrient?

• How can the materials and products be designed to enhance post-use value recovery?

• What is the value of the material for use in energy recovery?

• Has the material been designed for safe incineration in currently existing energy recovery systems?

For example, because it is difficult at this time to conceive of recovering cleaning products after use, it is sensible to design cleaning products as biological nutrients. Therefore, the cleaning product formulation must be amenable to wastewater treatment via the criteria of biodegradability and low aquatic toxicity. The packaging of these products, however, can be designed for a technical metabolism.

Asking the question, "How can this material or product be conceived as a nutrient?" drives different avenues of thinking. For example, eutrophication by excess phosphorus in manures is considered a pollution problem, while phosphorus is mined elsewhere for use as fertilizer. Thinking in terms of nutrients would suggest recovering P from manures for use as fertilizer, whether from anaerobically digested manures or as precipitated struvite. Likewise, nitrogen is a pollutant when emitted from cement kilns and coal-fired plants at the same time it is needed for growing food. Thinking in terms of nutrients would suggest that NOx could be recovered and transformed (it can be) for use as a nutrient.

The challenge of nutrient-metabolism thinking is building infrastructures for metabolizing materials to capture their highest value. While a material may be fully recoverable or recyclable, its value will not be realized if the infrastructure does not exist for recovery and recycling. On the large scale we envision for a truly sustainable industry, this cost can rarely be borne by individual companies, but groups of companies can organize, agree on common goals, and pool their resources to promote common infrastructures. There are already examples of such groups. Starting in summer 2003, GreenBlue organized a working group of companies in the packaging value chain - from consumer brands like Nike and Estee Lauder to commodity materials companies like MeadWestvaco and Dow - to explore cradle-to-cradle concepts and opportunities. In 2004 they formed the Sustainable Packaging Coalition to collectively outline and pursue strategies for creating cradle-to-cradle packaging products and systems (www.sustainablepackaging.org).

As industry moves toward renewable energy sources and materials, materials and products can be evaluated for their effective use of energy. This process includes the following considerations.

• What energy sources are used in its creation, distribution, use, and value recovery processes?

• How much energy is required for creation of the virgin material?

• How much energy is required for recovery by recycling versus other forms of value recovery? (For example, Dewulf and van Langenhove, 2002, evaluate metabolic efficiency of different solid waste treatment options including recycling, incineration with energy recovery, and landfilling with biogas/energy recovery using exergy analysis.)

Figure 5.6 illustrates a value recovery hierarchy that can be used to inform decisions about material cycling strategies.

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