Review Articles

Environmental Hazard, Part I

Chemicals Regulation Assessment

Environmental Hazard - Assessment of Chemicals and Products

Part Part Part Part

I: General Assessment Principles* II: Persistence and Degradability of Organic Chemicals III: The Limits to Single Compound Assessment IV: Life Cycle Assessment (LCA)

*) Parts II - IV will be published in the following issues of ESPR.

Walter Kl6pffer C. A. U. GmbH, Daimlerstrat~e 23, D-63303 Dreieich/Frankfurt, Germany Part II1: The Limits to Single Compound Assessment

Survey on the Series - Abstracts of Parts I - I V Part I: General Assessment Principles Hazard assessment is based both on estimates of environmental exposure and ecotoxic, toxic, and other noxious effects. Environmental criteria are given to enable a preliminary categorization of the hazard posed by a chemical. Depending on the amount and quality of data, the hazard estimates may be very rough (so that large safety margins are required), or more or less satisfactory. Risk assessment (not considered in detail) requires sufficient quantitative information, not available for most chemicals. Scoring systems give first approximations ff many chemicals are to be assessed with a minimum amount of data. More elaborate hazard assessment systems are shortly discussed. A main problem of all assessment procedures are the extremely toxic chemicals with no or very small production and the persistent chemicals without known adverse effects. Suggestions are made how to deal with these difficult cases.

Part II: Persistence and Degradability of Organic Chemicals The criteria "Persistence" and "Degradability" are defined and explained, starting from the "functional" definition of the environment. In this definition, the environment is the counterpart of the technosphere, which consists of all processes controlled by man. A substance is persistent if there are no sinks (degradation processes). It is shown that persistence is the central and most important criterium of environmental hazard assessment of organic chemicals. It follows that all substances released into the environment should be degradable, preferentially into small inorganic molecules (mineralization). As examples for persistent substances, the polychlorinated biphenyls (PCB), the chlorofluorohydrocarbons (CFC), bis(2ethylhexyl) phthalate (DEHP), and 2,3,7,8-tetrachloro-dibenzodioxin (TCDD) are discussed. Finally, an attempt to quantify persistence is made.

ESPR-Environ. Sci. & Pollut. Res. 1 (1) 47-53 (1994) 9 ecomed publishers, D-86899 Landsberg, Germany

The principles and basic assumptions of single compound assessment are briefly reviewed. Limitations to this approach are shown, especially with regard to complex mixtures of similar substances, substitution products, and complicated (final) products containing chemicals and materials produced by the chemical industry. A new thinking in product lines and life cycles is emerging, leading to new assessment methods. In some cases, substitution has not improved the environmental performance of products, since very similar chemicals were used as substitutes.

Part W: Life Cycle Assessment (LCA) The first LCAs (or eco-balances) were carried out in about 1970 when energy saving became a topic of general concern. Further pioneering work was performed in the 80's, but public interest has been induced only in the last few years. A modern LCA, as defined by SETAC, consists of four main components: Goal Definition, Inventory, Impact Assessment (including Valuation), and Improvement Analysis. The backbone of each LCA is the Inventory, a quantitative cradleto-grave analysis of all relevant mass and energy fluxes related the product(s) or systems studied, including the toxic or ecotoxic emissions. Impact Assessment is the environmental assessment of the emissions according to a set of criteria. In the broader approach (much discussed in Germany) of "Produkdinienanalyse', social and economic impacts are also considered in the Impact Assessment component. Impact Assessment also contains the "Valuation"-step which goes beyond (exact) science due the to normative and subjective factors invariably involved. Therefore, LCAs cannot replace political and economic decisions, but rather provide more rational (as opposed to emotional) and scientific foundations. The best use of LCA is the comparative assessment of products and systems serving the same purpose to improve manufacturing, waste management etc. over the whole life cycle. In order to compare different products or systems, a "functional unit" has to be defined, allowing a fair comparison between the alternatives. All data (e.g. total energy consumption, emissions, wastes, impacts) are related to this functional unit, so that a quantitative and differentiated comparison of different options becomes possible.

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Environmental Hazard, Part I

Review Articles

Environmental Hazard Cultural Sphere

- Assessment of Chemicals and Products

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Environmental hazard : Assessment of chemicals and products Part I: General assessment principles.

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