From toxic releases to damages on human health : a method for life cycle impact assessment, with a case study on domestic rainwater use

Life Cycle Assessment (LCA) is a tool developed to evaluate the environmental impact of a product or a system. After a decade of research in the LCA field, significant progress has been achieved but methodologies for the assessment of toxicological impacts on human health are still in the development phase. This dissertation contributes to the research required in this field. More specifically, its main objective is to develop a Life Cycle Impact Assessment (LCIA) procedure for human health respecting the guidance developed under the umbrella of the Society of Environmental Toxicology and Chemistry (SETAC). This means that we aim to implement an original procedure to quantify the potential carcinogenic and noncarcinogenic effects of toxic releases on human health (chapters 2 and 3), and to develop a new method describing the fate of atmospheric releases and the resulting exposure on humans (chapter 4). A framework summarized in figure 5.1 is also proposed to combine the effect assessment with the fate and exposure assessment, in order to derive a so-called human damage factor (chapter 5). A set of heavy metals (cadmium, chromium(VI), chromium(III), copper, methylmercury, beryllium, lead and inorganic arsenic) and of criteria air pollutants (CO, SO2, NOx and fine particles) is chosen for a full application of the procedure developed in this dissertation. The use of this procedure to the Cycleaupe case study is also part of the objectives of this research. This study aims to determine whether systems using rainwater or reducing water consumption are "friendlier" from an environmental perspective than conventional toilet flushing (chapter 6). Figure 5.1. Overview of the framework proposed in this thesis for assessing the damage induced on human health by a toxic released into air. In chapters 2 and 3, a new paradigm based on the effect dose ED10h is derived from the Risk Assessment concept of benchmark dose. It is proposed and explored for the first time in LCIA. The ED10h is defined as the best estimate of the dose which induces a 10% added risk over background for humans. Carcinogenic and noncarcinogenic risks towards humans are characterized by drawing a straight line from the ED10h down to the origin of the dose-response function. The slope of this straight line is called the slope factor and is denoted βED10. The linear dose-response function without threshold, which is assumed in this ED10-approach, is discussed. The ED10h is calculated for chemicals with bioassay data available in the Integrated Risk Information Service (IRIS) database provided by the US Environmental Protection Agency (US EPA). New correlations between the ED10h and the more widely available tumor dose TD50a (for carcinogenic effects) and the No Observable Adverse Effect Level NOAEL (for noncarcinogenic effects) are determined. They are applied to quantify the slope factor of more than 900 chemicals. A weighting of the different health outcomes associated with chemica