Prediction of the Environmental Fate of Chemicals

ISBN-13: 9781851664504 / Angielski / Twarda / 1990 / 285 str.

Yusaf Samiullah; Y. Samiullah;British Petroleum Company

Opis

Concern over the effects of chemicals in the environment has been increasing for many years. Environmental contamination by DDT, Aldrin, Dieldrin, mercury, PCBs, organotins and many other sub stances are all part of the public consciousness and have led to widespread attention to this topic. Some of the concerns have arisen because human health has been affected when contaminants have been consumed via the food chain-for instance in the case of 'Minimata disease' in Japan. In other cases, direct effects on other components of ecosystems have given cause for alarm. The toxic effects which any chemical can cause are a function of exposure and innate toxicity, i.e. of the ability to reach in sufficient quantity a site where a biological process can be disrupted and of the tendency to cause disruption when it gets there. The processes by which chemicals reach sites of toxic action are the subject of this book, and are a fundamental consideration in ecotoxi cology. When a chemical enters the environment e.g. via a spillage or in an effluent, it is potentially subject to a wide variety of processes which may eliminate it from the environment completely, modify it into a more or less harmful substance, or transfer it to another part of the environment. The processes involved are complex and highly variable, but it is essential to increase our understanding of them."

Spis treści

1 Introduction.- 2 Fundamental Properties of Chemicals.- 2.1. Introduction.- 2.2. Molecular and molar properties.- 2.2.1. Molecular structure.- 2.2.2. Additive and constitutive properties.- 2.2.3. The quantification of molecular structure.- 2.2.4. The development of an index of molecular connectivity.- 2.2.5. Applications of the molecular connectivity index.- 2.2.6. Structure-activity relationships and toxicology.- 2.3. Partition coefficients.- 2.3.1. Additive-constitutive properties.- 2.3.2. Fragment constants.- 2.3.3. Molecular connectivity.- 2.3.4. Experimental determination of partition coefficient.- 2.3.5. Activity coefficients.- 2.4. Partition coefficient and bioconcentration.- 3 Chemical Release and Environmental Pathways.- 3.1. Natural phenomena.- 3.2. Human activities.- 3.3. Manufacturing processes.- 3.4. Physical form and source description.- 3.5. Estimating releases.- 3.6. Environmental pathways.- 4 Modelling Strategies.- 4.1. Modelling philosophy.- 4.2. Model categories.- 4.3. Material balance and dimensional analysis.- 4.4. Partitioning models.- 4.5. Fugacity.- 4.5.1. Fugacity capacities (Z).- 4.5.2. Fugacity models.- 4.5.3. Calculation of fugacity capacity.- 4.6. System design.- 4.7. Model evaluation.- 5 The Soil Environment.- 5.1. Introduction.- 5.2. Physical processes.- 5.2.1. Adsorption.- 5.2.2. Diffusion.- 5.2.3. Volatilization.- 5.3. Chemical processes.- 5.3.1. Ionization.- 5.3.2. Hydrolysis.- 5.3.3. Oxidation/reduction.- 5.3.4. Complexation.- 5.4. Mathematical models of soil systems.- 5.4.1. Unsaturated soil zone (soil) modeling.- 5.4.2. Saturated soil zone (groundwater) modeling.- 5.4.3. Ranking models.- 5.4.4. Aquatic equilibrium models.- 6 The Aquatic Environment.- 6.1. Introduction.- 6.2. The hydrosphere.- 6.3. Physical processes.- 6.3.1. Hydrodynamic transport.- 6.3.2. Solubility in water.- 6.3.3. Volatilization from water.- 6.4. Chemical processes.- 6.4.1. Aqueous photolysis.- 6.4.2. Metals in water.- 6.5. Biodegradation..- 6.6. Mathematical models.- 6.6.1. Environmental rates approach.- 6.6.2. Model ecosystem approach.- 6.6.3. Aquatic fate models.- 7 The Atmospheric Environment.- 7.1. Introduction.- 7.2. Acidification pathways.- 7.2.1. Sulphur dioxide.- 7.2.2. Oxides of nitrogen.- 7.2.3. Chlorofluorocarbons and ozone depletion.- 7.3. Atmospheric sink mechanisms.- 7.3.1. Removal processes.- 7.4. Atmospheric residence time.- 7.5. Atmospheric dispersion modeling.- 7.5.1. Simple models.- 7.5.2. More complex models.- 8 Conclusions.- References and Bibliography.