Indika Rajapaksha,(B.Sc)

Environmental Officer, Centre for Environmental Justice

We see that many people use disinfectants for controlling COVID 19 virus without understanding the toxicity of the chemical. Prior to using a chemical disinfectant always consult the manufacturer’s instructions to determine the efficacy of the disinfectant against the biohazards and be sure to allow for sufficient contact time. Read label instructions on products to be followed (e.g., use- dilution, shelf life, storage, material compatibility, safe use, and disposal, the appropriate protective equipment for handling the disinfectant and disposal of disinfected treated materials.). Do not attempt to use a chemical disinfectant for a purpose it was not designed for.

WHO recommend to maintain hand hygiene with an alcohol-based hand rub for 20−30 seconds using the appropriate technique. If an alcohol-based hand rub and soap are not available, then using chlorinated water (0.05%) for hand washing is an option, but it is not ideal because frequent use may lead to dermatitis, which could increase the risk of infection and asthma and because prepared dilutions might be inaccurate. However, if other options are not available or feasible, using chlorinated water for hand washing is an option. WHO recommends using 70% ethyl alcohol to disinfect small areas between uses, such as reusable dedicated equipment (for example, thermometers) sodium hypochlorite at 0.5% (equivalent to 5000 ppm) for disinfecting surfaces.

Alcohols work through the disruption of cellular membranes, solubilization of lipids, and denaturation of proteins by acting directly on S-H functional groups. Ethyl and isopropyl alcohols are the two most widely used alcohols for their biocidal activity. These alcohols are effective against lipid-containing viruses and a broad spectrum of bacterial species. Ethyl alcohol, at concentrations of 60%–80%, is a potent virucidal agent inactivating all of the lipophilic viruses (e.g., herpes, vaccinia, and influenza virus) and many hydrophilic viruses. Isopropyl alcohol is not active against the nonlipid enteroviruses but is fully active against the lipid viruses.

Hypochlorites, the most widely used of the chlorine disinfectants, are available as liquid (e.g., sodium hypochlorite) or solid (e.g., calcium hypochlorite). Chlorine compounds are good disinfectants on clean surfaces, but are quickly inactivated by

organic matter, thus, reducing their biocidal activity. usually called household bleach. They have a broad spectrum of antimicrobial activity, do not leave toxic residues, are unaffected by water hardness, are inexpensive and fast acting , remove dried or fixed organisms and biofilms from surfaces, and have a low incidence of serious toxicity 

Aldehydes such as Formaldehyde, Paraformaldehyde, Glutaraldehyde are used as disinfectants. Fomaldehyde and its polymerized solid paraformaldehyde have broad-spectrum biocidal activity and are both effective for surface and space decontamination. As a liquid (5% concentration), formaldehyde is an effective liquid decontaminant. Its biocidal action is through alkylation of carboxyl, hydroxyl and

sulfhydryl groups on proteins and the ring nitrogen atoms of purine bases. Formaldehyde’s drawbacks are reduction in efficacy at refrigeration temperature, its pungent, irritating odor, and several safety concerns. Formaldehyde is presently considered to be a carcinogen or a cancer-suspect agent according to several regulatory agencies.

Phenolics are phenol (carbolic acid) derivatives and typically used at 1- 5% dilutions. These biocides act through membrane damage and are effective against enveloped viruses, rickettsiae, fungi and vegetative bacteria. They also retain more activity in the presence of organic material than other disinfectants. Cresols, hexachlorophene, alkyl- and chloro derivatives and diphenyls are more active than phenol itself. Phenol has several derivates, namely, cresol, creosote, lysol, and dettol. These are absorbed orally, through intact skin, by the GI tract, through inhalation by the respiratory tract, per rectum, and per vaginum. The toxicological actions of these compounds are similar to phenol but less severe. They should not spray unwisely. They have low concern on Skin Allergy and irritation, Moderate concern on Asthma, Cancer and environment while High concern on developmental and reproductive toxicity.  Its potentially harmful for developmental, endocrine, reproduction health including damage to DNA.

WHO has clearly stated that, in no way will consumption of alcohol protect you from COVID-19 or prevent you from being infected by it. Consuming alcohol will not destroy the virus, and its consumption is likely to increase the health risks if a person becomes infected with the virus. Alcohol works as a disinfectant on your skin, but it has no such effect within your system when ingested. Unfortunately, other toxic substances that may smell like ethanol can be added in adulterated beverages that are produced informally or illegally; or they may be present in alcoholic products that are not intended for human consumption, such as hand disinfectant. Added substances such as methanol can be fatal even in small amounts or may lead to blind­ness and kidney disease, among other problems. More than 700 people died after drinking methyl alcohol to cure corona virus recently.

It is essential to disinfect surfaces that are highly or frequently touched by public, such as hand railings, doorknobs, poles on transit vehicles, elevator buttons, park/ street benches etc. In the same time, public or sanitation workers must use them with care with protective equipment and their supervisors must make sure disinfectant is applied in a proper manner. CORONA is a hidden enemy and disinfectant used in proper manner can save many lives by containing the spread of virus.(END)