At the initial stages of the COVID 19 pandemic, health officials regarded disinfecting highly touched surfaces as an effective strategy to control the virus from spreading. Viruses, bacteria, and other microorganisms are killed using chemical disinfectants by destroying their cell walls and damaging their proteins through oxidation. In an attempt to control the outbreak several countries such as China, South Korea, France, Spain sprayed large amounts of disinfectant in heavily populated non-rural areas. They used trucks, mini tankers, drones, and robots to drench streets, parks, playgrounds, and public areas with chemicals that destroy the growth of viruses. Some countries like Indonesia used drones to disinfect homes from above and a village in Spain used tractors to dump hundreds of gallons of bleach on a public beach.
Experts, including WHO discredited this practice as futile and likely a risk as inhaling these chemicals causes respiratory irritation to people. Furthermore, when disinfectants such as bleach and ammonia are mixed it could release fatal chloramine gases. This is because the active component of most of the disinfectants used is harmful and corrosive chemical compounds such as chlorine releasing agents, oxidizing agents, and quaternary ammonium cations.
The biologists also commented from their research the usage of such substances in urban areas poses a significant threat to wildlife as it does to humans. On the other hand, human residents in urban dwellings can avoid chemical exposure by staying home, however that’s not the case with an urban organism. As the cities are under lock down, animals within urban areas go deeper into the cities and also explore the vacant streets, parks, and waterways. The massive disinfection taking place during lock down could affect a large amount of biodiversity due to the temporary boom in urban wildlife.
In January 2020, China was the first country to initiate disinfecting its cities and the aftermath resulted in reports of poisoned animals being turned in. An investigation in February by Chongqing Forestry found that at least 135 animals across 17 species which include wild boars, Siberian weasels, and blackbirds died due to the exposure to disinfectants. Now, when these chemical disinfectants are inhaled or ingested, they can irritate or corrode the mucous membranes of the respiratory and digestive tracts. Furthermore, exposure to large amounts can lead to death. As chlorine disinfectants are extremely toxic to terrestrial and aquatic animals, it’s being said, the food chain can also be affected by the bio accumulation of chlorine disinfectants.
Although this study hasn’t been conducted outside China, so it’s unclear how disinfecting outdoors has harmed urban wildlife and ecosystems in other countries. Just one commonly known case of wildlife-damaging disinfectants at Chongqing and a similar phenomenon has been observed in an artificial island off Miami, Florida where an association implemented an outdoor sanitation program where disinfection took place daily on the walkways, parks, and benches. After a week, several residents and their dogs fell sick.
In May, WHO recommended that disinfectants not to be used outdoors on the streets and sidewalks as they “are not considered as routes of infection for COVID-19” and spraying chemicals can cause a health concern for people’s health leading to respiratory, eye or skin irritation or damage.
While sanitizing highly touched surfaces is an effective method to kill pathogenic microorganisms that spread infectious diseases some scientific guidelines need to be followed. For instance, there are guidelines for using disinfectants in hospitals, laboratories, and homes compared to the large-scale application of disinfectants used in urban environments. Taking this into account, disinfecting should consider both public health and environmental safety. Secondly, to devise a non-toxic but effective disinfectant that is suitable for application outdoors and thirdly more research/studies to be conducted to understand the toxic effects of disinfectants on urban organisms and the environment.
References:
https://www.sciencedirect.com/science/article/pii/S0013935120308112?via%3Dihub#!
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