generally about classification, mechanism of action, the effects of toxic chemicals found in disinfectants, beneficial effects and how to minimize exposure to these disinfectants

1. ENVIRONMENTAL TOXICOLOGY
DISINFECTANTS
AYO NELSON
19/U/0080/PHL

2. INTRDUCTION
• Disinfectants are antimicrobial agents that are applied to the surface of non-living
objects to destroy microorganisms (bacteria, viruses, fungi, mold or mildews)
that are living on the objects.
• It does not necessarily kill all microorganisms but reduces them to a level
acceptable for a defined purpose.
• Disinfectants can be split into two broad groups, oxidizing and nonoxidizing
• However, other classifications also exist like alcohol, iodophors, phenolics etc.
• Its effects ranges from mild to severe depending on the dose and frequency of
exposure

3. Important definitions
• Sanitize: is to remove dirt and germs from surfaces/objects, through washing
and cleaning but not to the level of disinfection
• Antiseptic: similar to disinfectant but is applied to living tissue e.g.
skin/mucous membranes etc. with a view to killing microorganisms that can
be present on the tissue.
• Cleaning: the physical removal of foreign material e.g. dirt, soil, dust, organic
secretions etc.
• Sterilization: complete elimination or destruction of all forms of
microorganisms

4. CLASSIFICATION OF DISINFECTANTS
• Disinfectants can be split into two broad groups, oxidizing and
nonoxidizing.
• Oxidizing disinfectants include the;
 Halogens such as chlorine, iodine, bromine,
 chlorine dioxide
 oxygen-releasing materials such as peracetic acid and
hydrogen peroxide.

5. cont
Nonoxidizing disinfectants are as follows:
• quaternary ammonium compounds e.g benzalkonium chloride
• Amphoterics
• Biguanides
• acid anionics.
• Phenols mouthwashes, soaps
• Aldehyde such as formaldehyde, glutaraldehyde

6. Other classifications
Based on the components of disinfectants
• Alcohols
• Iodophors
• Phenolics
• Formaldehyde
• Hydrogen peroxide
• Sodium hypochlorite, etc.

7. Mechanism of their action
Oxidizing disinfectants
• It denatures proteins, disrupts the cell wall permeability and
oxidizes sulfhydryl and sulfur bonds in proteins, enzymes,
decrease oxygen uptake, inhibition of protein synthesis and
other metabolites which results in a loss of structure and leads
to cell lysis and death

8. Cont
Non oxidizing agent
• Aldehyde-alkylation
• Phenol –act as protoplasmic poison
• Quaternary ammonium compounds- inactivation of energy
producing enzymes

9. SOURCES OF EXPOSURE
• Surface waters, rain water, sediments, drinking water, groundwater,
industrial and urban runoff, and at hazardous waste sites.
• Workplace
• Inhalation
• contact with surfaces or objects which have been disinfected with the
products.
• Petroleum industry.

10. Cont.
• Heavy-duty surfactants
•Food e.g phenol have been found in foods such smoked pork belly,
mountain cheese, fried bacon, fried chicken, and black fermented tea.

11. Beneficial effects of disinfectants
• Effective in reducing microbial load on floors.
• Interrupts the transmission of communicable diseases
• Less environmental impact (aquatic or terrestrial)
• Less issues with disposal
• Produces more clean pleasing surfaces
• Water purification
• Waste water treatment
• Recommended for patients on isolation precautions
• Needed for surfaces contaminated by blood and other potentially infective
materials.

12. Toxicity of disinfectants
Dermal effects
• Skin dryness
• Mild skin reaction
• Caustic burns on the skin
• Skin dermatitis of the hands
GIT effects
• Irritation of the gastro-intestinal lining
• Nausea
• Vomiting
• Abdominal pain and diarrhea

13. Figure showing dermatitis and caustic burns by sodium hypochlorite

14. toxicity cont.
Eye effects
• Eye irritation and itching
• Decreased vision
• Lacrimation
Respiratory effects
• Lung irritation
• Shortness of breath
• Cough and sneezing

15. toxicity
• Affects the central nervous system and heart resulting in
dysarrhythmias, seizures and coma.
• Affects the liver
• Cognitive problems such as learning disability and behavior
change
• Birth defects and fertility problems in caged lab mice e.g Virex
and Quatricide

16. Toxicity of disinfectants
• Edema haemorrhage
• Cancer like nasal, lung cancers etc.
• Coma
• Convulsions
• Hypotension
• And death possibly

17. How to minimize exposure

18. Cont
• Proper disposal of empty containers of disinfectants
• The disinfectants should be stored under suitable temperature
• Manufacturer should provide an safety data sheet for each product
• Never mix two disinfectants together
• Clean in a ventilated space
• Be sure children aren’t in the room.
• Never mix products. Chemicals in cleaning products can have dangerous
reactions with one another. For example, the mixture of bleach and ammonia
creates deadly chloramine fumes

20. REFERENCE
• Lock S (1977) Disinfection, Sterilization and Preservation.
Philadelphia, PA: Lea & Febiger.
• Hugo WB (1971) Inhibition and Destruction of the Microbial Cell.
London: Academic Press

21. I may not be perfect but if others have made
it I too can do it
BLESSINGS