1. Assessment of bioavailability in aquatic(sediment) for metals
Key words : sediment ; heavy metal ;transformation ; bioavailability

2. the assessment system and existing forms in sediments for metals;
influence of metal Toxicity in sediments;
the biological toxicity of metals in sediments;
the principle of metal detoxification for aquatic animals
Conclusion and prospect

3. The assessment system and existing forms in sediments for metals
the assessing methods raised from the perspective of sedimentation;
metal Forms in Sediment and influence to aquatic organisms;

4. assessing methods
Geoaccumulation Index
The Pollution Load Index
The Potential Ecological Risk Index
Excess after Regression Analysis

5. 地累积指数法 Geoaccumulation Index

6. 潜在生态风险评价
The Potential Ecological Risk Index

7. 沉积物中重金属形态及对水生生物的影响
metal Forms in Sediment and influence to aquatic organisms
① 水溶性和可交换态； water-extractable phase and exchangeable forms
② 碳酸盐结合态； Carbonate combination state
③ 铁锰氧化物结合态； Iron manganese oxide combination patterns
④ 有机质、硫化物结合态； Organic and Sulfide combination state
⑤ 残余态 ; residual forms

8. influence extent ： Ion exchange state> Carbonate combination state>Iron
manganese oxide combination patterns> Organic and Sulfide combination state

9. The influence factors of metal Toxicity in sediments
metal forms influence on the biological toxicity ;
the relationship between Gap water ligand and metal toxicity;
the relationship between Surface oxidation of the sediments and metal toxicity;

10. the biological toxicity of metals in sediments
(a) Effects Range Low (ERL) and Effects Range Median (ERM) Screening Levels for Marine Sediments and
Acute/Chronic Marine Water Quality Criteria are Included
(b) Marine water quality values are for inorganic mercury. The chronic value of methylmercury is 0.025μg/L.

11. the principle of metal detoxification for aquatic animals
4.1 超氧化物歧化酶 (SOD)
4.1 谷胱甘肽（ GSH ）
4.2 过氧化氢酶
4.3 金属硫蛋白 (MT)

12. Conclusion and prospect
1. Based on the Researches on the total amount of metals in sediments, the
metal forms’ analysis is very important.
2. The development of advanced analysis methods and testing instrument,
accurate determination of trace elements’ chemical forms in the environment will
be the main development direction.
3. Strengthening the bioaccessibility researches on metal, set up a assessment
standard.