Biological agents disinfection

Although worries abound over contamination of the water supply, in reality, the task is quite difficult to accomplish. For example, a contaminant can be dumped into a reservoir, but studies show that the chemical does not mix throughout the entire body of water, even after many hours. There are multitudes of chemical and biological agents that can be used to contaminate the water supply, but all contaminants do not behave similarly. Not all contaminants are threats—some become unstable in water, while others require such large quantities to do harm that they could never be dumped without being noticed. Additionally, if a disinfectant residual is maintained in the water distribution system, that residual will react with the contaminant, and the populace will remain relatively safe. It will be extremely difficult for terrorists to successfully contaminate the water supply. 

The results of human activities described in the previous sections of this chapter have resulted in the release of thousands of pollutants into the environment. In a good portion of the world, ground- and surface waters are treated to disinfect biological agents and remove chemical pollutants prior to human consumption. Despite such treatment, the water consumed by almost all of the world s population is contaminated with chemical toxicants. In the United States, tap water tests from 1998 through 2003 on more than 39,000 water systems in 42 states, serving more than 231 million people detected 260 different pollutants. These are characterized by their sources in Tables 8.2-8.6. The data that follow in these tables, as well as those in Table 8.7, were compiled and reported by the EWGJ64I... 

Production areas where biological agents particularly resistant to disinfection (e.g. spore-forming bacteria) are handled should be separated and dedicated to that particular purpose until the biological agents have been inactivated. 

Liquid or solid wastes such as the debris after harvesting eggs, disposable culture bottles, unwanted cultures or biological agents, are best sterilized or disinfected before transfer from a contained area. However, alternatives such as sealed containers or piping may be appropriate in some cases. 

Table 7.2 summarizes recommended procedures for waste treatment and disposal procedures, including those needed for waste containing two different types of hazardous materials. For example, the second line indicates that organic liquids containing both toxic chemicals and biological agents must first be disinfected by a halogen and then disposed of with toxic waste. 

Use a chemical disinfectant solution to inactivate biological agent. For radioactive materials, treat excess disinfectant from rinses as radioactive liquid. Radioactive wastes should never be autoclaved. 

Decontamination of biological agents follows the same principles as for chemical agents using standard disinfecting agents (e.g. bleach). 

If required, immediate casualty decontamination for biological agents can be carried out effectively with detergent and water. Surfaces and equipment should be carefully disinfected with an appropriate detergent or bleach solution. Medical utensils will ideally be of the single-use, disposable t)q>e. Multi-use items will need cleaning and disinfection as appropriate, such as steam heating in autoclaves. 

Soap or detergent or special non-flammable dispersing agent to reduce fire hazards from flammable spillage and to reduce nuisance from lachrymators and strong-smelling fluids disinfectants for biological smells Sand in bucket or absorbents... 

The most common disinfectants in use nowadays are sodium hypochlorite, peracetic acid, ammonium quaternary salts, aldehydes, alcohols and phenol compounds. However, according to [25], all disinfectants require special attention. Indeed, glutaraldehyde, used widely in the past but now generally discarded in favour of compounds with a smaller impact on WWTP biological processes, has been found in concentrations ranging from 0.5 to 3.72 mg [15]. Moreover, triclosan, a common detergent and antimicrobial agent found in many personal care... 

It is therefore apparent why the physical chemistry of surfaces and the structure and activity of surface-active agents are also of interest to the medicinal chemist. Antimicrobial detergents and many disinfectants exert their activity by interacting with biological surfaces and are important examples of surface-active drug effects. 

Cheng TC, Rastogi VK et al. (2003). Compatibihty of CW agent degrading enzymes with disinfectants and foams. Proceedings of the joint service sientific conference on chemical biological defense research. Hunt Valley, USA... 

---