Biological agents absorption

Critical issues for decontamination that need to be adequately addressed for both military and civilian application include agent absorption into porous materials (e.g., concrete, wallboard, polymeric materials) and the challenges this poses. Validating the fate of low-level biological and chemical agents inside buildings and other structures also remains difficult. Sample collection efficiencies need to be... 

When the agent accumulates in the biological system (absorption exceeds metabolism and/or excretion)... 

Systemic Toxicity. Systemic toxicity refers to toxicity manifest in biologic tissues other than the tissues of contact with the offending agent. Absorption, at a minimum, must occur for systemic toxicity to exist distribution, metabolism, and/or excretion may also be involved. An example of systemic toxicity in which only absorption is involved is the red blood cell breakage (hemolysis) caused by the hydride gas arsine this hemolysis and subsequent anemia affect the central nervous system, the liver, and the kidneys. For most systemic toxins, a threshold level of agent must be reached before toxicity is manifest this threshold often represents the capacity of the body s defense mechanisms. With two general exceptions. 

Foams are used industrially and are important in rubber preparations (foamed-latex) and in fire fighting. The foam floats as a continuous layer across the burning surface, so preventing the evolution of inflammable vapours. Foams are also used in gas absorption and in the separation of proteins from biological fluids. See anti-foaming agents. 

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