At the moment, over 350.000 chemicals are registered worldwide for production and use. Their application, however, may harm human health and the environment. To manage the safety of chemicals,... Show moreAt the moment, over 350.000 chemicals are registered worldwide for production and use. Their application, however, may harm human health and the environment. To manage the safety of chemicals, particular chemical legislations are in place, which make use of risk and hazard assessments. However, there are several challenges for current risk and hazard assessments, including i) a lack of (reliable) data, and ii) a relative slow and inefficient evaluation and regulation process. In this thesis, I investigate specifically whether more extensive and targeted use of chemical similarity within risk and hazard assessment has the potential to improve these aspects. Chemical similarity could be a valuable factor as similarities between two chemicals could be a sign of similar physicochemical and/or toxic properties. The separate sections within this thesis specifically focus on chemical similarity in relation to screening, data generation and evaluation of substances. The results of this thesis indicate that chemical similarity could be used to identify and evaluate hazardous properties of single and groups of chemicals. Accordingly, I promote more extensive use of chemical similarity within risk and hazard assessment as it has the ability to circumvent several issues related to a lack of data and evaluation efficiency. Show less
This thesis describes the role of pollution, specifically neonicotinoid insecticides, as an actor of the ongoing biodiversity decline. Using a new research facility, the Living Lab, the effects of... Show moreThis thesis describes the role of pollution, specifically neonicotinoid insecticides, as an actor of the ongoing biodiversity decline. Using a new research facility, the Living Lab, the effects of field relevant concentrations of neonicotinoids and fertilizers to aquatic invertebrates was assessed in 36 experimental ditches. This showed that neonicotinoids had profound impacts on both single species as well as macroinvertebrate biodiversity and had severe consequences for the ecosystem processes the invertebrates fulfilled. Many of the results found in this thesis have not been discovered before because of the simplicity of standardized ecotoxicological testing, which not fully incorporates the myriad of ecological factors governing toxicity. It was found that the addition of fertilizers directly stimulated primary production which in turn reduced toxic effects indirectly. In addition, the neonicotinoid thiacloprid induced indirect effects on aquatic biodiversity which persisted much longer than the presence of this insecticide in the ditch ecosystem. The results in this thesis therefore show how the inclusion of environmentally realistic testing is essential to predict the actual risks of agrochemicals in the actual environment. Show less
Environmental life cycle assessment (LCA) is a method for the quantitative assessment of the environmental impacts of products. A number of impact categories are related to toxic effects of... Show moreEnvironmental life cycle assessment (LCA) is a method for the quantitative assessment of the environmental impacts of products. A number of impact categories are related to toxic effects of chemicals. Multimedia models for substance fate, supplemented with models for human exposure, have been developed in the context of human and environmental risk assessment (HERA). Different authors have adapted such models for use in LCA, largely on a continental level. It has sometimes been suggested to merge LCA toxicity assessment and HERA into one common tool. Here, it is demonstrated that LCA and HERA cannot be merged, due to a fundamental difference concerning their respective goals. Subsequently, adaptations to existing multimedia models are proposed to make it possible to extend multimedia models with a module for metals. The core of the thesis is formed by the GLOBOX model: a global, regionally differentiated fate, intake and effect model for LCA toxicity assessment. For emissions of any organic chemical or metal to any compartment in any country or at any sea, this model calculates region-specific characterisation factors. Finally, an updated set of LCA normalisation factors is provided, with which the relative contributions of a product to the different impact categories can be evaluated. Show less
