Effect of an uncontrolled fire and the subsequent fire fight on the chemical composition of landfill leachate

Landfill leachates sampled during and after an accidental landfill fire were analysed and the levels of selected metals and chemical compounds compared to those occurring in the leachate under normal conditions. The fire at the landfill site was put out by excavation and cooling by use of water. The investigation during the fire and fire fight revealed a moderate increase in the level of nitrogen and also in pH and conductivity. Heavy metals and COD in the leachate showed considerably increased levels. In general, the determined variables appeared to normalise within one week after the fire was extinguished. It can be concluded that landfill fires extinguished by excavation may lead to elevated leachate levels of especially COD and heavy metals, but that this is only a short-term effect.     

Der begriff der Erklärung in Physik und Biologie

It is argued that the causal explanation of an event or fact has the same structure in physics and biology. This structure is represented in essence by the deductivenomologic model of explanation. Besides causal explanations, functional and teleologic explanations are considered to be legitimate and indispensable in (comparative) biology. At least in those areas of comparative biology that are based on the use of the principle of homology, the explanation of an event or fact also follows the deductive-nomologic model.