key: cord-295034-em6z8mlu
authors: Daverey, Achlesh; Dutta, Kasturi
title: COVID-19: Eco-friendly hand hygiene for human and environmental safety
date: 2020-11-11
journal: J Environ Chem Eng
DOI: 10.1016/j.jece.2020.104754
sha: 
doc_id: 295034
cord_uid: em6z8mlu

The Coronavirus disease-2019 (COVID-19) outbreak is caused by a highly pathogenic novel coronavirus (SARS-CoV-2). To date, there is no prescribed medicine for COVID-19. Frequent handwashing with soap and the use of alcohol-based hand sanitizers is recommended by WHO for hand hygiene and to prevent the spread of COVID-19. However, there are safety concerns associated with the use of soaps and alcohol-based hand sanitizers. Therefore, the review aims to highlight the health and environmental concerns associated with the frequent use of soaps/detergents and alcohol-based hand sanitizers amid COVID-19. The potential of some of the natural detergents and sanitizing agents as eco-friendly alternatives to petrochemical-based soaps and alcohol-based hand rubs for hand hygiene are discussed. The market of soaps and hand sanitizers is expected to grow in the coming years and therefore, future research should be directed to develop eco-friendly soaps and hand sanitizers for human and environmental safety.

Coronavirus Diseases 2019 (COVID- 19) , which was first reported in Wuhan city (China) J o u r n a l P r e -p r o o f hydrogen peroxide (0.125% v/v as a preservative to inactivate bacterial spores) and glycerol (1.45% v/v as a humectantmoisturizing agent) diluted with sterilized distilled water or boiled water (WHO, 2010). In commercial products, propylene glycol is being used as a humectant. A viscosity enhancer such as alkyl acrylate cross-polymer, tetrahydroxypropyl-ethylenediamine, etc. is usually added in alcohol-based hand-rub gels. The cost of alcohol-based liquid and gel sanitizers is ranged around US$ 2.5-5.4 and US$ 8, respectively (WHO, 2010).

The mechanism of killing the microorganisms by soaps or detergents relies on the fact that they disrupt the lipophilic membrane of the cell wall of bacteria and other microorganisms including enveloped viruses (Ijaz et al., 2020) . Similarly, alcohol also dissolves the lipid membrane of microorganisms. Literature suggests that ethanol is highly effective (within 30 s) against almost all clinically relevant enveloped viruses including coronaviruses (SARS-CoV i.e. Severe Acute Respiratory Syndrome Coronavirus and MERS-CoV i.e. the Middle East Respiratory Syndrome Coronavirus, which belong to the same class of viruses as SARS-CoV-2), and influenza viruses (Kampf, 2018; Golin et al., 2020) . Therefore, alcohol-based hand sanitizers with alcohol content >60% v/v are popular and recommended by WHO and other national organizations such as CDC (Centers for Disease Control and Prevention), USA (CDC, 2020). The recent study by Kratzel et al. (2020) reports that SARS-CoV-2 was efficiently inactivated by ethanol and 2-propanol at a concentration of >30% v/v and by the two preparations recommended by WHO in 30 s. That's why frequent hand washing with soaps and hand hygiene with alcohol-based hand sanitizers has been recommended. The simplified mechanism of soaps/detergents and alcohol-based hand sanitizers are presented in Fig. 1 . pandemic is yet to be quantified.

The general safety issues associated with alcohol-based hand sanitizers are flammability of alcohol and toxicity due to the accidental ingestion of the sanitizer. In a recent review by Though the key components of hand sanitizers, alcohol and H 2 O 2 are in general not toxic externally, there is a concern of skin damage due to excessive use of hand sanitizers, which can lead to an inability of the skin to protect against other microorganisms or viruses (Mahmood et al., 2020). Younger kids (12-year-old children or younger) are at high risk due to accidental ingestion. In children, even a small dose of alcohol can cause alcohol poisoning. Therefore, the American Association of Poison Control Center (AAPCC) regarded hand sanitizers as emerging hazards. In the first six months (January to June 2020), 11,363 cases of exposure due to hand sanitizer have been reported according to AAPCC (https://aapcc.org/track/hand-sanitizer).

Methanol contamination has also been found in hand sanitizers probably due to the high demand for ethyl alcohol and isopropyl alcohol during this pandemic. FDA (U.S. Food & Drug Administration) found methanol contamination in several tested hand sanitizers (77 products as on July 23, 2020) and advises consumers not to use hand sanitizers from certain manufactures (FDA, 2020). Therefore, there is a dire need to replace alcohol-based hand sanitizers with nontoxic or low-toxic hand sanitizers for human and environmental safety.

Antimicrobial resistance due to the rampant use of antibiotics and other antimicrobial agents has become one of the major concerns worldwide. Apart from antimicrobials (antibiotics, antivirals, and antiparasitics), excessive use of surfactants, alcohol, and hydrogen peroxides are also known to cause resistance to microorganisms (Singer et 

Many microorganisms (bacteria, yeasts, and fungi) and plants produce surface-active agents called biosurfactants. Chemically they are amphiphilic compounds i.e. have both lipophilic and hydrophilic moieties in their structure. The biosurfactants possess similar properties as their chemical counterpart. For example, they efficiently reduce the surface and interfacial tensions between two phases, act as emulsifiers, and have foaming properties. Therefore, biosurfactants are potential agents to replace synthetic surfactants in soaps and detergents.

Based on their chemical structure microbial biosurfactants are classified as glycolipids, In the Kumaun region of Uttarakhand (India) 22 plant species have been used as traditional soaps and detergents. Different plant parts such as seeds, seed coats, barks, leaves, and young shoots, roots, ash have been used for washing and bathing purposes by the local people (Mehta and Bhatt, 2007) . Overall, all these properties of plant-derived natural soaps and detergents have the potential to replace the synthetic detergents and alcohol-based sanitizers. However, in-vitro J o u r n a l P r e -p r o o f activities of these natural biosurfactants against coronaviruses and SARS-CoV-2 has to be tested before using for hand hygiene.

Propylene glycol is the most commonly used humectant in hand sanitizers due to its low cost. A viscosity enhancer such as carbomer hydroxyethyl cellulose, sodium carboxymethyl cellulose, etc. is also added in the hand rubs. Aloe vera gel, a transparent mucilaginous jelly-like material (Lin et al., 2017) . Lemon balm oilan essential oil, which inhibits the enveloped herpes simplex virus and phenolic compounds from the Isatis indigotica, which inhibits coronavirus, could also inactivate SARS-CoV-2 (Jahan and Ahmet, 2020). However, the low-yield of essential oils and phenolic compounds could be a major factor for their commercial application in hand-sanitizers.

The main raw material used in soaps and hand sanitizers is petrochemicals based surfactant and 

Good hand hygiene prevents the spread of various diseases including COVID-19. Handwashing with soaps and the use of hand sanitizers to clean hands have increased immensely during the COVID-19 pandemic. The global market of detergents and hand sanitizers is expected to grow in the coming days. However, considering the harmful effects of chemical detergents and hand sanitizers, it is high time to replace them with eco-friendly natural agents. Several microbial J o u r n a l P r e -p r o o f biosurfactants and plant secondary metabolites possess detergent, antimicrobial and antiviral activities. Being non-toxic and biodegradable, these eco-friendly agents have tremendous potential to replace conventional soaps and hand sanitizers. Economical production of biosurfactants and extraction of bioactive antimicrobial agents from the plants will play a crucial role in their commercial application and sustainability as eco-friendly soaps and hand sanitizers and therefore further research is needed in this direction. 

COVID-19: Critical discussion on the applications and implications of chemicals in sanitizers and disinfectants

Antiviral effect of phytochemicals from medicinal plants: Applications and drug delivery strategies

Demonstrating the persistent antibacterial efficacy of a hand sanitizer containing benzalkonium chloride on human skin at 1, 2, and 4 hours after application

Biological activity of sophorolipids and their possible use as antiviral agents

Skin irritation and dryness associated with two hand-hygiene regimens: soap-and-water hand washing versus hand antisepsis with an alcoholic hand gel

Occurrence of surfactants in wastewater: hourly and seasonal variations in urban and industrial wastewaters from Seville (Southern Spain)

Hand Hygiene Recommendations: Guidance for Healthcare Providers about Hand Hygiene and COVID-19

Design of Sustainable Lip Gloss Formulation with Biosurfactants and Silica Particles

COVID-19 and frequent use of hand sanitizers; human health and environmental hazards by exposure pathways

Anti-influenza triterpenoid saponins (saikosaponins) from the roots of Bupleurum marginatum var. stenophyllum

FDA Updates on Hand Sanitizers with Methanol

Low-Toxic and Nonirritant Biosurfactant Surfactin and its Performances in Detergent Formulations

Plant-based natural saponins for Escherichia coli surface hygiene management. LWT -Food Science and Technology

Biosurfactants: production and potential applications in microbial enhanced oil recovery (MEOR)

Hand sanitizers: A review of ingredients, mechanisms of action, modes of delivery, and efficacy against coronaviruses

Optimisation of saponin extraction conditions with Camellia sinensis var. assamica seed and its application for a natural detergent

Application of rhamnolipid biosurfactant for bio-detergent formulation

Increased use of quaternary ammonium compounds during the SARS-CoV-2 pandemic and beyond: Consideration of environmental implications

Microbicidal Actives with Virucidal Efficacy against SARS-CoV-2

Potentials of plant-based substance to inhabit and probable cure for the COVID-19

Valorization of selected fruit and vegetable wastes as bioactive compounds: Opportunities and challenges

Use of wastes for sophorolipids production as a transition to circular economy: state of the art and perspectives

Hand Sanitizers: A Review on Formulation Aspects, Adverse Effects, and Regulations

Efficacy of ethanol against viruses in hand disinfection

Inactivation of Severe Acute Respiratory Syndrome Coronavirus 2 by WHO-Recommended Hand Rub Formulations and Alcohols

Evaluation of surfactant removal efficiency in selected domestic wastewater treatment plants in Poland

Antiviral natural products and herbal medicines

Effective inhibition of MERS-CoV infection by resveratrol

Nonantibiotic antimicrobial triclosan induces multiple antibiotic resistance through genetic mutation

The therapeutic properties and applications of Aloe vera: A review

Traditional soap and detergent yielding plants of Uttaranchal

Benzalkonium chlorides: uses, regulatory status, and microbial resistance

Heavy use of hand sanitizer boosts antimicrobial resistance

Aloe vera (L.) Burm. F. as a Potential Anti-COVID-19 Plant: A Mini-review of Its Antiviral Activity

The role of surfactants in wastewater treatment: Impact, removal and future techniques: A critical review

Bioactive phenolic compounds from agri-food wastes: An update on green and sustainable extraction methodologies

Microbial biosurfactants for oil spill remediation: pitfalls and potentials

Increasing tolerance of hospital Enterococcus faecium to handwash alcohols

Characterization and authentication of commercial cleaning products formulated with biobased surfactants by stable carbon isotope ratio

Polyphylla saponin I has antiviral activity against influenza A virus

Quillaja Saponin Characteristics and Functional Properties

Antiviral activity obtained from aqueous extracts of the Chilean soapbark tree (Quillaja saponaria Molina)

Review of Antimicrobial Resistance in the Environment and Its Relevance to Environmental Regulators

Biosurfactant production: emerging trends and promising strategies

Production, formulation and cost estimation of a commercial biosurfactant

Mechanism of inactivation of enveloped viruses by the biosurfactant surfactin from Bacillus subtilis

Guide to Local Production: WHO-Recommended Handrub Formulations

Coronavirus disease (COVID-19) advice for the public

Potential changes in soil properties following irrigation with surfactant-rich greywater

Surfactin Inhibits Membrane Fusion during Invasion of Epithelial Cells by Enveloped Viruses

New sustainable alternatives to reduce the production costs for surfactin 50 years after the discovery

Surfactants at environmentally relevant concentrations interfere the inducible defense of Scenedesmus obliquus and the implications for ecological risk assessment