| Popis: |
In this thesis, 10-day sediment-based static bioassay tests on the amphipod Corophium volutator (Pallas, termed C. volutator) were initially designed and set up, in order to investigate mobility, bioaccumulation and toxicity of the metals with an emphasis on arsenic in arsenic sulphides (AsS, As2S3, and Fe[AsS]) and coal-mining spoils (from Kirkcaldy, Scotland and Huainan, China). The marine amphipod is sensitive to metals (As, Cd, Pb, and Ba), which were generally recognised as the most important metals in the drainage water of coal-mining spoils. C.volutator, under the designed test, could indicate the release of contaminants derived from the arsenic sulphides and the spoils for environmental implications, and is of potential applicability in characterising the sulphide-bearing spoils in terms of toxicology monitoring. Toxicity and arsenic bioaccumulation in C.volutator varied greatly between different exposure minerals, in decreasing order: AsS≥As2S3>>Fe[AsS], in association with the 10-day LD50 (referring to mineral-spiked ratio in test sediment) of 0.032-0.073%, 0.050-0.097%, and 0.245-0.289%, respectively and 10-day LC50 value (referring to test media) of 0.42-0.95 mg As L-1 to the bio-indicator. It was found that there is an inverse logarithmic correlation between BAFs and arsenic concentrations in the media. The presence of predominantly arsenite (AsIII) in the mineral leachates and bioaccumulation of inorganic arsenic (AsIII and AsV) associated with eliminated biomethylation (to DMAV) in exposed organism have a close linkage to the relatively lower LC50 values during 10-day exposure duration. This infers that the arsenic-sulphur complex in the exposure media may plays a key role for mineral release and biological-effect of toxic arsenic. |
