Occurrence and fate of organic contaminants in wastes

This thesis deals with the determination of organic contaminants in wastes and is part of the multidisciplinary faculty programme 'Biological waste in circulation between urban and rural areas - biology and flow of energy and material' which started at SLU in 1994. To ensure long-term sustainability of food production it is important to recycle resources such as the nutrients and organic material in organic waste. The biodegradable fraction of source separated household waste is attractive as raw material for composting and anaerobic digestion, because the products can be used in agriculture and horticulture. Quality is an important aspect on compost and anaerobically digested organic household waste, and it is important to ensure that the products are not contaminated. As the available information on organic contaminants in the biodegradable fraction of household waste and the products thereof is limited, an important goal with this work was to increase the knowledge of organic contaminants in these material as a foundation for future studies to reduce the environmental risk from these materials. Chlorinated paraffins (CPs) were found in fresh household waste. CPs are a complex mixture of chlorinated alkanes with varying (10-30) carbon chain lengts and varying (30- 70%) unspecific chlorination. The high numbers of isomers and homologues complicates the determination of CPs. We found that multivariate analysis can be used to interpret chromatographic data of CPs and this was used to characterise the CP contamination of houshold waste. It is presently impossible to pin-point the source of CP contamination using the data available, but most probably the contamination occurs during the collection of the waste. To further improve the determination of CPs an extraction method using high diffusion liquids, pressurised liquid extraction (PLE) was developed. PLE was shown to be a suitable technique for extracting CPs from complex matrices such as fresh household waste. A source close to the collection chain is also indicated for polychlorinated biphenyls (PCB). The PCB-profile found in the fresh household waste resembles that of a low chlorinated technical product. The PCB-profile expected in this type of material would originate from waste of animal origin in which the low chlorinated congeners have been degraded and the more highly chlorinated and persistent congeners dominate. Differences in the degradation rate of PCBs between composting and anaerbically degestion of the waste were also observed. A third indication of a contamination source in the collection chain is the presence of the n-alkanes in the fresh and anaerobically digested household waste, which suggest a petrogenic rather than a biogenic origin. Since the major part of the organic fraction of household waste is of plant origin, much of which is treated with pesticides, it was expected to find pesticides in the waste. Many of the pesticides were not degraded during composting or anaerobic digestion, and two that were not found in the waste were found in compost or anaerobically sludge. In these cases the organic bulk material is mineralized more rapidly than the pesticides. The anaerobic biotransformation of nonylphenol mono- and diethoxylates (NPEOI-2) was studied in sludge, landfilled sludge and landfilled municipal solid waste. The NPEO1-2 are degradation products of nonylphenol ethoxylates (heavy duty surfactants) and are further degraded to nonylphenol (NP) which is far more persistent and ecotoxic than its parental compo

Endogenous differential mortality, non monitored effort and optimal non linear taxation

This paper studies the normative problem of redistribution among individuals who can influence their longevity through a non-monetary effort but have different taste for effort. As benchmarks, we first present the laissez-faire and the first best. In the first best, the level of effort is always lower than in the laissez-faire as the social planner takes into account the consequences of higher survival on the budget constraint. However, since we suppose that effort is private and non-monetary (like exercising), it is reasonable to think that the social planner has no control over it. Thus, we modify our framework and assume for the rest of the paper that effort is determined by the individual while the social planner only allocates consumptions. Under full information with non monitored effort, early consumption is preferred to future consumption and the high-survival individual obtains higher future consumption. Under asymmetric information, the distortion is identical for the low-survival individual while the direction of the distortion for the high-survival individual is ambiguous. We finally show how to decentralize these allocations through a perfect annuity market and (positive or negative) taxes on annuities.annuities, effort, differential mortality, non linear taxation.

Endogenous Differential Mortality, Non-Contractible Effort and Non Linear Taxation

This paper studies a problem of non linear taxation when individuals have different longevities resulting from a non-monetary effort (like exercising). We first present the laissez-faire and the first best. Like Becker and Philipson (1998), we find that the laissez-faire level of effort is too high compared with the first best, because individuals do not internalize the impact of survival on the return of their savings. We also claim that because of its non-monetary form, effort is not contractible. That is why we modify our framework and assume, for the rest of the paper, that effort is determined by the individual while the social planner only allocates consumptions. It turns out that, under full information, a tax on the return of annuitized savings is desirable for both types. This tax is higher for the low-survival individual. Under asymmetric information, the low-survival individual still faces a tax while the high-survival individual might now face a positive or negative tax on annuities. Interestingly, our results depend on the value of life.annuities, effort, differential mortality, non linear taxation, value of life

Exactly What Happens After the Anscombe-Aumann Race? Representing Preferences in Vague Environments

This paper derives a representation of preferences for a choice theory with vague environments; vague in the sense that the agent does not know the precise lotteries over outcomes conditional on states. Instead, he knows only a possible set of these lotteries for each state. Thus, this paper's main departure from the standard subjective expected utility model is to relax an assumption about the environment, rather than weakening the axiomatic structure. My model is consistent with the behavior observed in the Ellsberg experiment. It can capture the same type of behavior as the multiple priors models, but can also result in behavior that is different from both the behavior implied by standard subjective expected utility models and the behavior implied by the multiple priors models.Decision Theory, Vagueness, Utility, Optimism