Effect of Chemical Environment

A. A. Kossiakoff, M. Ultsch, S. White, C. Eigenbrot, Neutron Structure of Subtilisin BPN Effects of Chemical Environment on Hydrogen-Bonding Geometries and the Pattern of Hydrogen-Deuterium Exchange in Secondary Structure Elements , Biochemistry 1991, 30, 1211-1221. 

Hojo, H., Tsuda, K. Effects of Chemical Environments and Stress on Corrosion Behaviors of Glass Fiber Reinforced Plastics and Vinyl Ester Resin, Proc., 34th Ann. Tech. Conf., Reinf. Plast./Compos. Inst., SPI, Sec. 13-B, 1979... 

Bai Q. and Kohlstedt D. L. (1993) Effects of chemical environment on the solubility and incorporation mechanism for hydrogen in olivine. Phys. Chem. Mineral. 19, 460-471. 

Hilling and Charles (1965) analysed sub-critical crack velocity, v under general conditions including the effect of chemical environment which can give rise to surface flaws. The velocity, v, of crack propagation is given by. 

Isotopic Exchange Reactions. - In the previous section the kinetics of isotope exchange processes were discussed. The emphasis of this section will be on mechanisms of exchange processes. Exchange reactions can provide valuable information about the breaking and making of bonds at the catalyst surface, the effects of chemical environment on the reactivity of bonds and the turnover of molecules between the gas phase and adsorbed state. Surface adsorbed intermediates, thus identified, may also participate in other, more complicated, reactions on the same catalyst. 

Guide to the Effect of Chemical Environments on Plastics (Continued)... 

This test method evaluates the effect of a chemical environment on pipe when in a deflected condition. It has been found that effects of chemical environments can be accelerated by strain induced by deflection. This information is useful and necessary... 

Professional association of people concerned with the effects of chemicals on human and animal health and the environment and who have conducted and published original investigations in some phase of toxicology. Has offices in Brussels, Pensacola, Florida, and Bangor, Australia. 

Fig. 15-11 Effects of strong complexation on metal ion toxicity, (a) Increasing concentration of NTA, a strong multi-dentate complexing agent, decreases the toxicity of Cd to grass shrimp. All systems have equal concentrations of total Cd. (b) When the results are replotted showing survival as a function of Cd concentration, the data for all concentrations of NTA collapse to a single curve. (Reprinted with permission from W. G. Sunda et al. (1978). Effect of chemical speciation on toxicity of cadmium to grass shrimp, Palaemonetes pugio importance of free cadmium ions. Environ. Sci. Technol. 12,409-413, American Chemical Society.)...

CICADs are concise documents that provide summaries of the relevant scientific information concerning the potential effects of chemicals upon human health and/or the environment. They are usually based on selected national or regional evaluation documents or on existing EHCs. Before acceptance for publication as CICADs by IPCS, these documents undergo extensive peer review by internationally selected experts to ensure their completeness, accuracy in the way in which the original data are represented, and the validity of the conclusions drawn. 

In the quest for better methods of establishing the environmental safety (or otherwise) of chemicals, interest has grown in the use of microcosms and meso-cosms—artificial systems in which the effects of chemicals on populations and communities can be tested in a controlled way, with replication of treatments. Mesocosms have been defined as bounded and partially enclosed outdoor units that closely resemble the natural environment, especially the aquatic environment (Crossland 1994). Microcosms are smaller and less complex multispecies systems. They are less comparable with the real world than are mesocosms. Experimental ponds and model streams are examples of mesocosms (for examples, see Caquet et al. 2000, Giddings et al. 2001, and Solomon et al. 2001). The effects of chemicals at the levels of population and community can be tested in mesocosms, although the extent to which such effects can be related to events in the natural environment is questionable. Although mesocosms have been developed by both industrial... 

Section 4.5). Of these, mesocosms have stimulated the greatest interest. In these, replicated and controlled tests can be carried out to establish the effects of chemicals upon the structure and function of the (artihcial) communities they contain. The major problem is relating effects produced in mesocosms to events in the real world (see Crossland 1994). Nevertheless, it can be argued that mesocosms do incorporate certain relationships (e.g., predator/prey) and processes (e.g., carbon cycle) that are found in the outside world, and they test the effects of chemicals on these. Once again, the judicious use of biomarker assays during the course of mesocosm studies may help to relate effects of chemicals measured by them with similar effects in the natural environment. 

TSCATS is an online index to unpublished, nonconfidential studies covering chemical testing results and adverse effects of chemicals on health and ecological systems. The studies are submitted by US industry to EPA under several sections of the Toxic Substance Control Act (TSCA). There are four types of documents in the database Section 4 chemical testing results, Section 8(d) health and safety studies, Section 8(e) substantial risk of injury to health or the environment notices, and voluntary documents submitted to EPA known as a For Your Information (FYI) notice. 

The need to balance costs against benefits both in the public and private sectors resulted in a search for methods of predicting the fate and effects of chemicals in the environment. Actual field testing of all cases of interest is both too costly and too dangerous to perform. Mathematical models, therefore, have been developed to provide descriptive tools and predictive approaches to this problem. At the symposium on which this book is based, a collection of user-oriented information was presented and covered the following aspects of environmental fate modeling ... 

Santos V, Morao A, Pacheco Ml, Cirfaco L, Lopes A (2008) Electrochemical degradation of azo dyes on BDD effect of chemical structure and operating conditions on the combustion efficiency. J Environ Eng Manage 18(3) 193-204... 

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