Explain briefly how do toxic metals transport through the aquatic environment? b) Briefly discuss the processes of bioaccumulation and biomagnification. c) Explain the effects of presence of a ligand on the behaviour of metal ions in the aquatic environment. d) Explain briefly, the BOD and COD tests, and how they relate to oxygen consuming e) Explain the major pathway and specific role of phosphorus cycle in the food chain. f) State the major FIVE (5) steps of the nitrogen cycle, and discuss the importance of nitrogen cycle in an ecosystem. wastes.