Natural environmental/toxicity considerations

The organization of this edition follows that of the earlier one. Part I (Chapters 1-3) provides an introduction to the types and properties of functional fillers and their polymer composites, including melt mixing aspects. Part II (Chapters 4-6) discusses different types of surface modifiers and coupling agents for fillers. Part III discusses in detail individual types of man-made, natural, in-situ generated and mineral fillers, and their functions. High aspect ratio fillers (Chapters 7-10), low aspect ratio fillers (Chapters 11-16), and a variety of specialty fillers for specific applications (Chapters 17-24) are included in Part III. Each filler chapter, typically, contains information on (a) production methods, (b) structure and properties, (c) suppliers, (d) cost/availability, (e) environmental/toxicity considerations, and (f) applications based on primary and secondary functions. 

Nuclear-physical methods ai e the basic ones in controlling environmental pollution which results from nucleai -power complexes and power plants work. Oil and gas production leads to the extraction of radio nuclides of natural origin in considerable amounts, which later spread from oil-slimes and water wastes in the neighborhoods of oil and gas producing entei prises. Similaidy, toxic and radioactive elements can pollute environment in case of mineral deposits extraction. 

Chitosan, the most abundant marine mucopolysaccharide, is derived from chitin by alkaline deacetylation, and possesses versatile biological properties such as biocompatibility, biodegradability, and a non-toxic nature. Due to these characteristics, considerable attention has been given to its industrial applications in the food, pharmaceutical, agricultural, and environmental industries. Currently, chitosan can be considered as a potential marine nutraceutical because its remarkable biological activities have been investigated and reported, in order to exploit its nutraceutical... 

Summarizing, the use of natural products as miticides in apiculture, with the exception of some substances, is not widespread. In extensive laboratory tests many compounds showed significant acaricidal properties. However, very few of them have proven to be effective when applied in field trials. Considerable variations in local environmental and colony conditions can affect efficacy. In case of mixtures, such as essential oils, the difficulty in obtaining standardized compounds also affects treatment predictability. Nevertheless, identifying new acaricide compounds with low toxicity to honey bees is fundamental for providing candidate compounds for field trials. Furthermore, the development of... 

The initial species present, their relative concentrations, the induction of their enzymes, and their ability to acclimate once exposed to a chemical are likely to vary considerably, depending upon such environmental parameters as temperature, salinity, pH, oxygen concentration (aerobic or anaerobic), redox potential, concentration and nature of various substrates and nutrients, concentration of heavy metals (toxicity), and effects (synergistic and antagonistic) of associated microflora (Howard and Banerjee, 1984). Many of the parameters affect the biodegradation of chemicals in the environment as well as in biodegradation test systems used to simulate the environment. 

One last consideration during the selection process of a suitable surfactant or other facilitating agent must be an examination of toxicity and biodegradability issues so that no adverse impact on the environment or on human health occurs. For example, upon completion of SEAR, any residual HOCs or surfactants remaining in the aquifer should be easily biodegradable or, at minimum, have a relatively low toxicity. Because NOMs and cyclodextrins are naturally-occurring materials, they may have less of an environmental impact than conventional chemical surfactants and may be... 

The preceding brief description of the nature and scope of biochemical and molecular toxicology should make clear that the study of toxic action is a many-faceted subject, covering all aspects from the initial environmental contact with a toxicant to its toxic endpoints and to its ultimate excretion back into the environment. A considerable amount of material is summarized in the chapters following, but many essentials still remain to be discovered. 

Nonetheless, a (partial) switch to renewables is desirable for other reasons, such as biocompatibility, biodegradability and lower toxicity, i.e. renewable raw materials leave a smaller environmental footprint [3]. That the chemical industry has been slow to make the transition, in the three decades following the Report of the Club of Rome, is a consequence of the fact that oil and natural gas are excellent basic feedstocks and highly atom efficient, low waste, catalytic procedures are available for their conversion into commodity chemicals. The same cannot be said for the fine chemicals industry where processes are, generally speaking, much less efficient in many respects and there is considerable room for improvement. 

Acid gas, a mixture of hydrogen sulfide and carbon dioxide, is a toxic by-product of the sweetening of natural gas. Acid-gas injection has become an environmentally friendly way to dispose of this by-product. In the remainder of this book, the detailed design considerations for acid-gas injection are presented. 

The direct determination of many heavy and toxic elements is not possible in various environmental materials due to insufficient detection limits of analytical methods and the very low concentrations of most of the elements of interest. The sensitivity of analytical methods may be increased if before measurement concentration of the element(s) is performed. During this stage the concentration of the element is increased and very often the matrix is eliminated which further may reduce spectral interferences (Hoste et al., 1971 Das et al., 1983 Toelgyessy and Kyrs, 1989 Stoep-pler, 1992). The preconcentration step is performed when the quantity of the analyte element in the aliquot is below the limit of determination and there are no possibilities for increase of volume or mass of the sample. The detection and determination limits of most of the analytical methods indicate that a considerable number of elements mostly in atmospheric air and natural water cannot be determined without preconcentration. 

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