文档介绍：General Principles
for Designing
Safer Chemicals
Methods
for Designing
Safer Chemicals
Chapter 3 Designing Safer Chemicals
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General Principles for Designing Safer Chemicals
Two main ways to avoid Hazard and Toxicity
1:make it not possible to enter the body,
2:make it not possible to affect the bio-chemical and physiological processes(生物化学和生理过程)hazardously.
Direct hazard:to human beings, to environment
Indirect hazard:
to human beings, to environment
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: General Principles for Designing Safer Chemicals
They refer to the reduction in exposure by designing chemicals that influence important physical and chemical properties related to environmental distribution and the up-take of the chemical by man and other anisms.
External considerations
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External considerations
Structural designs or redesigns that will increase degradation rates and
those that reduce volatility(挥发性), persistence in the environment or conversion in the environment to biologically active substances
represent examples of major external considerations for reducing exposure.
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External considerations
Molecular designs that reduce or impede(妨碍) absorption by man, animals and aquatic life(水生生物) also represent important external considerations.
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External considerations------ Reduction of exposure or accessibility
A. Properties related to environmental distribution/dispersion
1. Volatility/density/melting point
2. Water solubility
3. Persistence/biodegradation
a. oxidation, b. hydrolysis,
c. microbial degradation
4. Conversion to biologically active substances
5. Conversion to biologically inactive substances
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External considerations------ Reduction of exposure or accessibility
B. Properties related to uptake anisms
1. Volatility
2. Lipophilicity(亲油性)
3. Molecular size
4. Degradation
a. hydrolysis(水解), b. Effect of pH,
c. susceptibility to digestive enzymes(消化酶)
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External considerations------ Re