Biologies toxicity mechanisms

Kudo, A. (1983). Physical/chemical/biological removal mechanisms of mercury in a receiving stream. In Toxic Materials - Methods for Control" (N. E. Armstrong and A. Kudo, eds). The Center for Research in Water Resources, University of Texas at Austin, Austin, TX. 

The current thinking is that whole effluent toxicity assessment provides a practical, biologically relevant mechanism for providing additional hazard data on the combined effects of all the contaminants present in a complex effluent. There is reasonable confidence that an appropriate set of acute, and to a lesser extent chronic, toxicity assessments exist that have been used in many countries over the past two decades. Consequently, there is guidance on limit conditions for... 

The third section of the periodic table comprises transition metals or the d-group elements, which are involved in many biological defence mechanisms against toxic radicals. As in chemical catalysis the same metals are active in biochemical systems. Surprisingly these redox mediators are involved in both, the generation and the removal of reactive oxygen species. 

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