External considerations A Properties related to environmental distribution/dispersion .s 1. volatility/density/melting point 2. Water solubility 令3. Persistence/ biodegradation(生物降解性 a. oxidation, b. hydrolysis, c. microbial degradation(微生物降解性 "s 4. Conversion to biologically active substances ,s 5. Conversion to biologically inactive substances
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 (生物降解性) a. oxidation, b. hydrolysis, c. microbial degradation（微生物降解性） ❖ 4. Conversion to biologically active substances ❖ 5. Conversion to biologically inactive substances
External considerations. Reduction of exposure or accessibility i . B Properties related to uptake by organisms 冷1. Volatility(挥发性) 小2. Lipophilicity(亲油性) & 3 Molecular size 4. Degradation(摩解性) a. hydrolysis(水解),b. Effect of ph C susceptibility to digestive enzymes a3 (敏感性) (消化酶)
❖ B. Properties related to uptake by organisms ❖ 1. Volatility （挥发性） ❖ 2. Lipophilicity（亲油性） ❖ 3. Molecular size ❖ 4. Degradation （降解性） a. hydrolysis（水解）, b. Effect of pH, c. susceptibility to digestive enzymes （敏感性） （消化酶） External considerations: Reduction of exposure or accessibility
External considerations Structural designs or redesigns ncrease degradation rates, reduce volatility(挥发 f), reduce persistence time in the environment and possibility of conversion to biologically active substances in the environment Molecular designs: reduce or impede(妨得) absorption by man animals and aquatic life(水生生物).B
❖ Structural designs or redesigns: increase degradation rates, reduce volatility（挥发 性）, reduce persistence time in the environment and possibility of conversion to biologically active substances in the environment. External considerations ❖ Molecular designs : reduce or impede（妨碍） absorption by man, animals and aquatic life（水生生物）
External considerations. Reduction of exposure or accessibility i . C. Consideration of routes of absorption by man animals or aquatic life o 1. skin/eyes 2. Lungs 3. Gastrointestinal tract(消化系统) *4.Gills(5) or other specific routes
❖ C. Consideration of routes of absorption by man, animals or aquatic life ❖ 1. Skin/eyes ❖ 2. Lungs ❖ 3. Gastrointestinal tract（消化系统） ❖ 4. Gills(鳃) or other specific routes External considerations: Reduction of exposure or accessibility
External considerations. Reduction of exposure or accessibility 今B0 accumulation(生物聚集)0r Bio- magnificati0n(生物放大): It refers to the increase of tissue concentration of a chemical as it progresses up the food chain 生物放大:指食物链向上一级进展,化学物质在 组织中的浓度增大的现象
❖ Bio-accumulation（生物聚集）or Bio-magnification （生物放大）: ❖ It refers to the increase of tissue concentration of a chemical as it progresses up the food chain. ❖ 生物放大：指食物链向上一级进展，化学物质在 组织中的浓度增大的现象。 External considerations: Reduction of exposure or accessibility