DISCUSSION DRAFT
Material Assessment Strategy for End of Life Vehicles (ELV)
Materials Assessment Program
Suppliers Partnership for the Environment
Thomas G. Osimitz, PhD, DABT, ERT
Wiebke Droege, PhD
Science Strategies, LLC
Charlottesville, VA 22902
September 23, 2013
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I. Background
In 2007, the Suppliers Partnership for the Environment (SP), an innovative collaboration between automobile manufacturers, their suppliers, and the U.S. Environmental Protection Agency (USEPA) formed the Chemical Issues Work Group to provide a forum for discussing emerging chemical issues within the automotive supply chain, to share best practices and to develop a common approach to material risk assessment for automotive products. Since this formation, the Work Group developed a Material Assessment Strategy (MAS) for evaluating potential chemical exposures to passengers in automotive compartments.
As a follow-on phase to the development of the MAS for vehicle interiors and the assessment of chemicals found in brake and tire wear debris, the Work Group embarked on Phase 4 of the project to include end of life vehicles (ELV). The MAS ELV project is aligned with actions at the state level to address end of product life concerns for products of all types, not limited to vehicles. The embracing of product life cycle management that explicitly addresses disposal and end of product life is one of the most significant trends in chemical management. Policy strategies include green chemistry and green design (i.e., research to develop safer alternatives and product design), pollution prevention planning and technical assistance, requiring manufacturer take-back of end of life products and/or requiring product recycling. As of 2013, 37 states have adopted policies to promote pollution prevention. Thirty-four states have established chemical product stewardship policies, six of which have Green Chemistry and a cornerstone of their programs. The recently established Green Chemistry Initiative (GCI) by the State of California directs the Department of Toxic Substance Control to identify chemicals of concern in consumer products and consider exposures and during their manufacture and after disposal when the useful life of the product is done. Depending upon their analysis, the state may restrict or ban the use of problematic chemicals in the products of on the basis of end of life properties.
This guidance document supports the risk assessment of potential environmental exposures associated with chemicals found in ELV. The three guidelines include:
· Hazard Assessment and Dose-response Assessment
· Exposure Assessment
· Risk Assessment
The purpose of this document is to provide guidance for a preliminary risk assessment for chemicals found in ELV that may enter the environment. It is not intended to be a detailed operating procedure that by itself can be used to conduct comprehensive assessments. Rather, it should be considered a guide to the principles underlying hazard assessment and dose-response assessment and an overview of data sources, evaluation procedures, and risk characterization logic.
II. Purpose
The purpose of the Materials Assessment Strategy is to provide a systematic review of hazard and risk of chemicals associated with ELV. This includes:
· A procedure to identify and evaluate the information needed to assess the hazard, exposure and risk of the chemicals of interest;
· A way to screen chemicals for a limited, but important group of hazards of highest concern to stakeholders;
· A means of providing for prioritization of concern for chemicals based on both hazard and risk (as appropriate).
III. Categories of Interest of Materials Used in Vehicles
Creating a system to evaluate the many chemicals used to make the various materials in an auto is a daunting challenge. To simplify this, it is useful to categorize the materials present in autos and consider each of the chemicals associated with each category separately, as needed. One way to organize these chemicals is by their current segregated grouping for recovery/recycling/disposal. Included are comments on the fate of the materials at the end of vehicle life (e.g., landfill, recycling, etc.).
A. Materials and articles that are commonly recovered from ELV (>75% of available amount)
1. Batteries – Although batteries comprise only about 1% of a vehicle by weight, it is important that they are recovered and recycled because of lead’s hazardous properties.
2. Ferrous and Non-Ferrous Metals - Approximately 76% of the weight of an average car is metal, primarily steel. Most of these metals are recycled.
3. Fluids – Oil, brake fluid, power steering fluid, antifreeze, and windshield washer fluid are usually recovered during the initial phase of the vehicle (about 2% of vehicle by weight).
4. Mercury – Mercury (though being phased out) is mainly used in switches. These are typically removed from the vehicle for recycling.
5. Tires - Representing about 3% of the weight of a vehicle, tires are burned to produce fuel, or recycled into a variety of products, including automotive products. Fine mesh crumb or ground rubber can be used as protective liners for truck boxes or as ingredients in new tires. Most tires are recovered for reuse / recycling.
B. Materials and articles that are less frequently recovered from ELV (<25% of available amount)
1. Electronics – Navigation systems, audio equipment, etc. all contribute to an increasing amount of potentially hazardous e-waste coming from ELV.
2. Glass - Used windshield glass, which is 3% of the vehicle weight, has been a very low priority for recycling.
3. Plastics - The second largest component of vehicles by weight is plastic (about 10%). Currently, the amount of plastics being recycled is very low. One reason for this is the variety of different polymers being used, which include polypropylene (PP), polyethylene (PE), polyurethane (PU), and polyvinyl chloride (PVC). Polypropylene accounts for the majority of car plastics (about 40%), and is used in bumpers, wheel arch liners and dashboards. Like PE and PU, commonly found in seat foam, it is easily recycled. PVC accounts for about 12% of the plastic used in vehicles but is not readily recycled.
4. Rubber – Accounting for about 2% of the vehicle weight, unless recovered, rubber, like textiles, ends up in the shredder residue.
5. Textiles – Carpeting and upholstery (1% of the vehicle by weight) usually end up in the shredder residue that goes to the landfill.
IV. Automobile Recycling
Identification of potential exposure routes and scenarios is important to ensure that the most significant risks are accounted for. Figures 1, 2 illustrate the process by which autos are dismantled and recycled or otherwise disposed of.
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Once the car has reached end-of-life it enters a phase of initial resource recovery. This is the time in which readily accessible valuable and reusable or recyclable materials are removed from the car. This includes oils and fuels, batteries, refrigerants, mercury switches, and tires. The potential for human and environmental exposure during this process is relatively low, provided good handling and industrial hygiene practices are followed. Exceptions would be cases where spills occur or proper recycling procedures are not followed.
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Following this phase, the car is dismantled to recover usable parts. These parts and components enter the used car parts marketplace and are no longer present as the vehicle proceeds to recycling. Because these parts are reused, the potential for human and environmental exposure to chemicals contained therein is limited.
The now stripped-down vehicle that remains after this stage goes to the shredder. Shredders typically break the remnant down into fist-sized pieces. Ferrous and nonferrous metals are removed; the remainder is referred to as auto shredder residue
Figure 1: ELV Management – Part 1
Figure 2: ELV Management – Part 2
(ASR) or fluff. Although the content varies to some extent, it consists primarily of complex materials such as coatings, fiber, insulation, and plastic (Table 1).
Table 1: Typical Material Content of ASR
Material (%) / Data SourceA / B / C / D / E / F
Dust, soil, etc. / 10-20
Elastomers (including rubber) / 10-32 / 20 / 5.3 / 21 / 2.6 / 18
Fibers (textile, wood, paper) / 4-26 / 25 / 53.7 / 10 / 10
Glass, ceramics, electric materials / 3-16 / 3-5 / 19
Metals / ~20 / 8.1 / 13.5 / 3
Minerals (glass, sand, grit, dust, etc.) / 35
Others / 7.9 / 4 / 0.6 / 21
Oils, water / 15-17
Paints, lacquer / 3-10 / 5
Plastics / 30-48 / 20 / 21.5 / 41 / 33
Plastics (foam, PUR) / 15
Plastics (including coatings, textiles / 83.1
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Sources:
A. Keller (2003)
B. Galavgno et al. (2001)
C. Das et al. (1995)
D. Mirabile et al. (2002)
E. Lanoir et al. (1997)
F. Ambrose et al. (2002)
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The nonferrous and ferrous metals usually go to recyclers or smelters and are processed. The ASR ends up either in an incinerator or in a landfill. Local conditions and regulations have a great influence over whether ASR is incinerated or landfilled.
Populations with the greatest possible exposure include waste management workers and residents close to landfill or incinerators. The following of good industrial hygiene procedures (such as the use of personal protective equipment) will likely reduce or eliminate worker exposure to the residue. Addressing potential airborne exposures from the incinerator is problematic, given the unknown engineering efficiencies by which the residue is combusted. The greater the efficiency of incineration, the lower the likelihood of hazardous chemicals being produced and released. Overall we consider the potential for routine human exposure to ASR to be low. In contrast to the case for human exposure, the most likely potential exposure will be environmental. This could occur from on-site storage of ASR prior to landfilling, haphazard disposal, or leaching from landfills. Thus, the focus of the MAS will be to assess chemicals likely to be present in ASR and most likely to present and opportunity for environmental exposure.
V. Identifying Chemicals Likely to be Present in ASR
A thorough evaluation of the impact of chemicals present in ASR depends upon knowledge of the chemicals present in each material used in the assembly of the auto. In many cases obtaining such information is difficult. Even if complete chemical disclosure is not achievable, suppliers are likely to flag chemicals of interest contained on the Global Automotive Declarable Substance List (GADSL).
Chemicals are listed on GASDL based on the following criteria:
· The substance is regulated, or is projected to be regulated by a governmental agency or authority, or toxicology studies conducted under OECD (Organization for Economic Cooperation & Development) guidelines for testing chemicals indicated that the substance may be associated with a significant hazard to human health and/or the environment, and its presence in a material or part in a vehicle may create a significant risk to human health and/or the environment.
· Other scientifically valid methodology, based on the weight of evidence, may also be considered.
Declaration of a substance does not mean, however, that the substance is prohibited from being used in vehicle parts or is to be de-selected from use, but it will point to chemicals that are likely to be relevant to the MAS.
Although GADSL can help identify chemicals that are likely to be of concern in, it may not always reflect the most recent science and thus listing on GADSL may lag the knowledge of the possible hazard associated with a given chemical. For this reason, to the extent possible, we recommend that all of the remaining known ingredients likely to be found in the ASR should be subject to a hazard assessment.
VI. Identification of Hazard and Other Properties Associated with the Chemicals
For the purpose of the MAS we define hazard as the inherent ability of a chemical to cause certain toxic effects, regardless of dose. Because of our focus on ASR and the potential environmental exposures, the primary hazard of concern will be aquatic toxicity.
Although not considered hazard properties, persistence and bioaccumulation potential will also be considered. Chemicals that have all three properties (persistence, bioaccumulation potential, and toxicity) are considered “PBTs.” Chemicals with these properties are often subject to transport, through air, water, and migratory species (birds and mammals), across large areas and thus deposited far from their place of release, where they may accumulate in terrestrial and aquatic ecosystems. Consequently, information on persistence and bioaccumulation potential should also be included. These two properties will be considered along with aquatic toxicity to determine whether the chemical is a PBT. The MAS considers PBTs to be of special concern and will still undergo quantitative risk assessment for aquatic toxicity, but their use should be carefully considered regardless of the outcome of the risk assessment. Figure 3 illustrates the screening process for PBTs.
Figure 3: PBT Screening
A. Aquatic Toxicity
Given that the predominant pathway by chemicals contained in ASR to enter the environment is from leachate washed into surface waters, toxicity to aquatic organisms is the toxicity parameter of primary concern. Data may be available from laboratory studies on the chemicals of interest with respect to acute and/or chronic toxicity to aquatic organisms. Acute toxicology studies are those in which the test organisms are typically exposed to substances from 24-96 hours (relatively short in comparison to the duration of the life-cycle of the organisms). Effects are normally expressed as median lethal or effect concentrations (LC50 or EC50), which is the test concentration at which 50% of the organisms are affected or at which 50% effect is measured for a defined quantified endpoint (e.g. algae growth rate). In contrast, the duration of chronic studies widely depends on the species used (e.g., daphnia vs. fish), and is usually a significant portion of the life-cycle of the organism. Endpoints of interest include growth, survival, and reproduction. The key measurement is the No Observed Effect Concentration (NOEC), the most frequently used parameter. The following are of most interest: