COVID-19: Israeli researchers develop a method that turns tap water into a powerful disinfectants that can kill bacteria and viruses

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Israeli researchers have developed a method to produce tap water-based, environmentally safe but powerful disinfectants that can kill bacteria and viruses, including coronaviruses, according to an announcement by Bar Ilan University.

The method was developed and patented by Dr. Eran Avraham, Dr. Izaak Cohen, and  Prof. Doron Aurbach, head of the electrochemistry group, at Bar Ilan University’s Department of Chemistry and Institute of Nanotechnology and Advanced Materials.

The technology works through an array of nanometer-shaped electrodes with unique surface properties, the university explained in a statement, adding that the combination of the water and electrodes creates a cleaning material with an effective anti-bacterial capability for microorganisms (bacteria, viruses, and spores).

At the same time, it is safe for macro-organisms (like skin cells) and does not contaminate groundwater.

The tech enables the preparation of a variety of solutions for clean spaces such as spray-aerosols for disinfecting surfaces, disinfectant wipes, liquids for hand-washing, shoe-washing, washing and disinfecting floors, air-conditioning systems, washing machines, and dry fog air-purifiers, and containers for immersion.

“The ability to produce electrodes in a variety of shapes and textures makes the technology suitable to almost any application – from a ‘cassette’ in an air conditioner, a container for washing fish and meat, to disinfection and removal of pesticides from vegetables and fruit, mobile spray, a device for manufacturing disposable antibacterial cloths and many other applications – even masks and gloves,” the university said.

In electrode-free containers, the disinfectants can remain effective for two months and may be sold in recyclable bottles. For reusable bottled products, a fairly simple process can be applied to enable long-term use, according to the university.

The researchers also say the antiseptic capability is “100 times more effective” than household bleach, for example, and low concentrations of between 50 and 200 mg per liter are enough to disinfect.

By contrast, bleach requires between 5,000 and 20,000 mg per liter. The produced materials are also safe for skin and do not cause burns or dryness.

The researchers are now looking into the possibility that the materials may be able to treat skin wounds, the university said.

The materials were recently tested by Dr. Inna Kalt and Dr.Tatiana Borodiansky Shteinberg in the lab of Prof. Ronit Sarid, of the Mina and Everard Goodman Faculty of Life Sciences at Bar Ilan University.

They were proven against the herpes simplex virus, a skin infection with no known cure, and the human coronavirus OC43, one out of seven known coronaviruses that infect humans, and the type that causes the common cold.

“Both viruses were completely eliminated when exposed to the disinfectants for different periods of time. The structural characteristics of OC43 are similar to those of recent SARS-CoV-2 suggesting that this virus will also be easily eliminated with this disinfectant,” Professor Sarid said in the statement.

SARS-CoV-2 emerged sometime in December 2019 in Wuhan, China. Over the past five months, this coronavirus has spread across the world, infecting over four million people and killing over 280,000 so far. Countries are still grappling with the global pandemic.

In addition to social distancing, frequent hand-washing, and mask-wearing, health officials have also urged the cleaning and disinfecting of surfaces as preventative measures.

According to multiple studies, the coronavirus can live on surfaces for several days, including plastic, stainless steel, copper, and cardboard.


Definitions

The U.S. Environmental Protection Agency (U.S. EPA) registers all non-food-contact surface sanitizers and disinfectants as pesticides. Below are some important definitions.

Non-Food-Contact Surface Sanitizers

According to the U.S. EPA, a non-food-contact surface sanitizer is “a substance, or mixture of substances, that reduces the bacterial population in the inanimate environment by significant numbers, (e.g., 3-log10 reduction) or more, but does not destroy or eliminate all bacteria.”3 This

  • log reduction in bacteria equates to reduction of the test organisms by 99.9%. As such, these products are used to reduce, but not necessarily eliminate, microorganisms from inanimate surfaces.

The required test organisms for this type of sanitizer are Staphylococcus aureus plus either Klebsiella pneumoniae or Enterobacter aerogenes. In order for a product to be registered by the U.S. EPA as a sanitizer for non-food-contact surfaces, it must demonstrate the ability to cause a bacterial reduction of at least 99.9% within 5 minutes.4 Efficacy claims against additional pathogens will be listed on the label.

Surface sanitizers tend to be less concentrated than disinfectants and, therefore, less expensive. For example, one concentrated Accelerated Hydrogen Peroxide (AHP™) product called Oxivir Five 16 is registered as a non- food-contact surface sanitizer when it is diluted 1:128, and it is registered as a healthcare environment disinfectant at a stronger dilution of 1:16. That makes the sanitizing solution of Oxivir 1/8th, or about 12% of the cost of the disinfecting solution.

Often, the use of surface sanitizers (instead of disinfectants) can save time because their dwell time is typically shorter. In such cases, a product (with the same AI concentration) can be registered as a sanitizer with one dwell time (up to 5 minutes) and as a disinfectant with another, longer dwell time (up to 10 minutes).

Pre-diluted, ready-to-use (RTU) products such as Lysol Brand III Disinfecting All Purpose Cleaner,5 which contains 3.2% lactic acid, exemplify this. This product is a non-food-contact surface sanitizer in 30 seconds and a disinfectant in 10 minutes.

In some cases, where the disinfectant concentration is stronger than the sanitizer, users may need to undertake an extra step of rinsing off the disinfectant solution after the requisite dwell time in order to prevent exposure to the chemical by facility users or corrosive effects to surface materials.

For example, Ecolab’s 65 Disinfecting Heavy Duty Bathroom Cleaner, a concentrate that contains 3.05% caprylic acid, is registered as a healthcare- environment disinfectant when ¾ cup (6 oz.) of it is diluted with one gallon of water and left on the surface for 10 minutes.

According to the EPA-approved label for this product, after the requisite dwell time, users are supposed to wipe the surface with a damp cloth or sponge, and then rinse it with potable water.

In contrast, no rinse step is required when this product is used as a non-food-contact surface sanitizer (i.e., diluted only 3 oz. per gallon of water). Not only is the dwell time cut in half, but also the residual solution can be left on the surface to air dry.

Surface Disinfectants

According to the U.S. EPA, a disinfectant is a “substance, or mixture of substances, that destroys or irreversibly inactivates bacteria, fungi and viruses, but not necessarily their spores.6

In order for a product to be registered by the U.S. EPA as a surface disinfectant, it must demonstrate the ability to prevent the test bacteria from growing in 59 out of 60 samples when left on for the stated dwell time, which may be no more than 10 minutes.7

The U.S. EPA has three classifications of disinfecting claims, each with their own test organisms8. In order of ‘strength’, they are as follows:

Although many companies, microbiologists, and other experts in the field often refer to a disinfectant as causing 99.999% (5-log) kill in no more than 10 minutes, the U.S. EPA does not define disinfectants in these terms.

Rather, this is an estimate, or assumption, and perhaps an attempt to align the definition of ‘disinfectant’ with that of ‘food-contact surface sanitizer’ (99.999% kill required in 1 minute or less) or ‘non-food-contact surface sanitizer’ (99.9% kill in 5 minutes or less). It is not an official definition and cannot be referenced in the U.S. EPA or other regulatory agency literature.

  1. Healthcare Environment Disinfecting Claim: To make this claim, a disinfectant must meet test requirements (prevent bacteria from growing in 59/60 trials) for Staphylococcus aureus, Salmonella enterica, and Pseudomonas aeruginosa in 10 minutes or less. Healthcare environment disinfectants are not required to claim efficacy against any viruses or fungi, although many do.
  • General or Broad Spectrum Disinfecting Claim: To make this claim, a disinfectant must meet test requirements for at least two bacteria: Staphylococcus aureus (gram-positive) and Salmonella enterica (gram-negative) in 10 minutes or less.
  • Limited Efficacy Disinfecting Claim: To make this claim, a disinfectant must meet test requirements for either Staphylococcus aureus (representing gram-positive bacteria) OR Salmonella enterica (representing gram-negative bacteria), but not both in 10 minutes or less. Pinalen, which lists 5% pine oil as its only active ingredient, is an example of a “limited disinfectant against gram-negative bacteria”.9 Another example is Windex Multi-surface Antibacterial10 (with 0.18% lactic acid), which claims efficacy against Salmonella but not Staphylococcus. Its U.S. EPA-approved label provides instructions on how “to disinfect and kill gram-negative bacteria on hard, non-porous surfaces.”

Some disinfectants can make different disinfecting claims depending on the dwell time or dilution that is used. For example, the U.S. EPA-approved label for the concentrated chlorine bleach product included in this evaluation states that it is registered as a general disinfectant when it is diluted ½ cup per gallon of water with a five-minute dwell time. In contrast, it is registered as a healthcare-environment disinfectant only when (at the same dilution) it is left on the surface for 10 minutes, because that is the dwell time needed to kill Pseudomonas aeruginosa.

Compared to non-food-contact surface sanitizers, disinfectants are often much stronger and, therefore, more expensive. Or, in some cases, they simply need to be left on the surface longer to achieve a higher efficacy against bacteria and other pathogens. For more information on where to use sanitizers, disinfectants, or green cleaners, refer to Appendix C: Best Practices for Cleaning, Sanitizing, and Disinfecting.

While disinfectants are required to demonstrate efficacy only against a small number of bacteria, they are typically effective against a wide range of bacteria (including, in some cases, antibiotic-resistant strains such as MRSA) as well as viruses (such as influenza (flu) virus and HIV), and/or fungi (such as athlete’s foot fungus, mold and mildew). Because of the increasing concern about viruses such as the Influenza “flu” virus, Norovirus, HIV, and others, there is an increasing use of disinfectants that are also registered as virucides (see below).

Disinfectants and non-food-contact surface sanitizers may not be appropriate for use on surfaces that contact food. For these applications a product specifically registered as a food-contact surface sanitizer must be employed, and these are subject to different efficacy criteria.

Other definitions

  • Cleaner-Disinfectant: According to the U.S. EPA, “an antimicrobial agent identified as a ‘one-step’ cleaner-disinfectant, cleaner-sanitizer, or one intended to be effective in the presence of organic soil must be tested for efficacy by the appropriate method(s) which have been modified to include a representative organic soil such as 5% blood serum.” The agency warns that even when such products are used, “when the surface to be treated has heavy soil deposits, a cleaning step must be recommended prior to application of the antimicrobial agent.”11
  • Dwell time: Dwell time is the length of time a product must remain wet on a surface to reach the kill level specified on the label. Together, efficacy and dwell time indicate how effectively and quickly a surface sanitizing or disinfecting product works compared to others in its class.
  • Efficacy: Efficacy here refers only to the level of microbial kill against specific bacteria, viruses and/or fungi claimed on the most current U.S. EPA-approved label for a given product. In many cases a compound may actually be capable of killing many other kinds of microbes, but the manufacturer has chosen to submit data only on a more limited subset.
  • Fungicide: An antimicrobial product may be labeled as a fungicide if it is registered by the U.S. EPA as effective against at least one fungus such as athlete’s foot fungus, Candida albicans, mold or mildew. To make this claim about a specific fungus, a product must completely kill the test microorganism on the surfaces tested in 59 out of 60 attempts.12
  • Germicide: A product may be labeled a germicide if it is registered by the U.S. EPA as a general disinfectant (effective against both Staphylococcus and Salmonella bacteria) AND a virucide or a fungicide.
  • Respiratory sensitizer: Under the Globally Harmonized System of Classifying and Labeling of Chemicals (GHS)13, a respiratory sensitizer is a “substance that induces hypersensitivity of the airways following inhalation of the substance.”
  • Reactive Airway Dysfunction Syndrome (RADS): RADS chemicals can cause an asthma-like syndrome after a single exposure to high levels of an irritating vapor, fume, or smoke.14
  • Virucide: An antimicrobial product may be labeled as a virucide if the U.S. EPA registers it as effective at killing a least one virus. Such claims may be made for products that are also bacterial disinfectants or sanitizers and must be restricted to those viruses that have actually been tested.15

Methods

Scope

This Alternatives Analysis is based on a comparison of 11 active ingredients commonly found in non-food- contact surface sanitizers and disinfectantsii. Beside disinfectant products, we also examined data on electrolyzed water and steam devices, although this review was limited. Active ingredients reviewed were:

  • Caprylic acid (aka Octanoic acid)
    • Citric acid
    • Hydrogen peroxide (H2O2), including stabilized or “accelerated” products
    • Lactic acid
    • Ortho-phenylphenol (OPP)
    • Peroxyacetic acid (PAA) + hydrogen peroxide (H2O2)
    • Pine oil
    • Quaternary ammonium chloride compounds (“quats”)
    • Silver + citric acid (or hydrogen peroxide)
    • Sodium hypochlorite (e.g., chlorine bleach, CAS #7681-52-9)
    • Thymol (a component of thyme oil)

The recommendations in this report are based on two levels of review:

ii Note: Hydrogen chloride, not evaluated in this assessment, is also found as a breakdown product in some disinfectants. It is toxic, very acidic and corrosive, and listed by AOEC as an asthmagen associated with Reactive Airways Dysfunction Syndrome (RADS).

  • Active Ingredient Review, which summarizes:
    • Health risks (such as the potential to cause cancer, asthma, or corrosive damage to the eyes or skin); and
    • Environmental risks (such as the potential to persist in the environment, harm fish and other aquatic species, or cause eutrophication).

The active ingredient review focused on chronic health and environmental hazards because these hazards are less dependent on ingredient concentration.

  • Sample Product Review, which summarizes a broader array of health and environmental risks as well as the efficacy claims, dwell times and surface and chemical compatibilities of 28 sample registered disinfectants containing one of the 11 active ingredients (“AIs”) listed above. The intent was to evaluate sample products that represent active ingredient concentrations found in available products.  Usually this meant a complete evaluation of two products per active ingredient (one concentrate and one ready- to-use formulation), although the actual number of products reviewed varied. In addition, several other products were partially reviewed, largely to determine whether products with different concentrations of AIs listed similar health effects, efficacy or dwell time. See Appendix D, Table 8 for the list of sample disinfecting products that were included in this alternatives assessment. Overall, 33 disinfectants and 24 non-food-contact sanitizers were reviewed. (Note that a separate table of non-food-contact sanitizers was not included because the differences in efficacy were found to be negligible. Instead, information on the sanitizing efficacy and dwell time of the evaluated disinfectants was noted in Appendix D, Table 9.)

Review at the product level permitted a review of acute hazards such as eye and skin irritation. While these are key worker health issues, they were assigned less priority for products available in closed- loop dilution systems, which prevent workers from being exposed to concentrated products.

Information Sources

In the Active Ingredient Review, the primary information sources included the U.S. EPA’s Reregistration Eligibility Documents (REDs) for each antimicrobial ingredient studied, material safety data sheets (MSDSs) for the active ingredient, data available in summary format through the Pharos Project16, and peer-reviewed scientific journal articles.

The Pharos Project ranking system is informed by the benchmarking system of the Green Screen for Safer Chemicals17 developed by Clean Production Action. The foundation of the Green Screen method is the Principles of Green Chemistry18 and the work of the US Environmental Protection Agency’s (EPA’s) Design for the Environment (DfE). In addition, the assessment relied on the following sources to evaluate specific health risks:

  • Cancer: California’s “Prop 65” List of Chemicals Known to the State of California to Cause Cancer, Birth Defects and Other Reproductive Harm19 (with a cancer notation); National Toxicology Program’s Report on Carcinogens (12th Edition); and the International Agency for Research on Cancer (IARC)’s Agents Classified by the IARC Monographs document.20
  • Reproductive toxicity: California’s “Prop 65” List of Chemicals Known to the State of California to Cause Cancer, Birth Defects and Other Reproductive Harm (with a notation about reproductive or developmental effects).
  • Asthma: Association of Occupational and Environmental Clinics’ (AOEC) list of asthmagens21 and the National Institutes of Health’s 2011 report, Healthy Environments: A Compilation of Substances Linked to Asthma.22
  • Skin Sensitization: European Union’s REACH designation code of R43: “May cause sensitization by skin contact”.23

In the Sample Product Review, the primary information sources included the most recent U.S. EPA-approved product label, information found in the CA DPR Product/Label Database, and the MSDS for at least one concentrated and one pre-diluted, ready-to-use (RTU) product per active ingredient or combination of active

ingredients (e.g., silver + citric acid or PAA + H2O2). Some of the information that was typically found in these information sources included each product’s:

  • Skin, eye and respiratory irritation potential
  • pH
  • HMIS score (which evaluates a product for health, flammability, and reactivity)
  • Registered efficacy against specific bacteria, viruses, and/or fungi
  • Registered dwell time (which may vary by pathogen, product concentration, application method, or other factors)
  • Surface compatibility
  • Presence of chemicals not listed as active ingredients that may contribute to the product’s health/environmental impacts or efficacy (e.g., phosphorus, ethyl alcohol or quats)

The AI-level assessment gives information on chronic issues such as cancer and asthma risks, while the product-level evaluation better represents acute hazards of the product as formulated.

Evaluation and Coding Methods

Below is a description of the methods that were used to code and evaluate the information collected during this review.

·         Cancer

  • 0/Green: Carcinogenicity to Humans Not Known or Suspected: This chemical is not on the CA Prop 65 List with a cancer notation, is not listed in the National Toxicology Program (NTP) Report on Carcinogens (12th Edition) as a “Known” or “Reasonably Anticipated Human Carcinogen”, or is not on the following IARC cancer lists 1: “Carcinogenic to Humans”, 2A: “Probably Carcinogenic to Humans”, or 2B: “Possibly Carcinogenic to Humans”. In addition, there is no mention of carcinogenicity in the U.S. EPA RED or MSDS for this active ingredient; and no known studies raising concern about carcinogenicity were found.
    • 1/Yellow – Suspected Human Carcinogen: This chemical is listed as “Reasonably Anticipated as a Human Carcinogen” in the NTP Report on Carcinogens (12th Edition)24; is on the IARC 2A List (“Probably Carcinogenic to Humans”) or 2B List (“Possibly Carcinogenic to Humans”); or “Suspected Carcinogen” is mentioned in the EPA RED or the active ingredient’s MSDS.
    • 2/Red – Known Human Carcinogen: This chemical is on the CA Prop 65 List with a “cancer” notation; is listed as a “Known Human Carcinogen” in the NTP’s Report on Carcinogens (12th Edition); or is on the IARC Group 1 List (“Carcinogenic to Humans”).

·         Reproductive or Developmental Toxicity

  • 0/Green – Reproductive or Developmental Toxicity Not Known or Suspected: This chemical is not on the CA Prop 65 List with a reproductive or developmental toxicity notation and no references to birth defects or other reproductive or developmental toxicity issues were found in the EPA RED or the MSDS for this active ingredient.
    • 1/Yellow – Suspected Reproductive or Developmental Toxicity: “Suspected Reproductive or Developmental Toxin” is mentioned in the EPA RED, in the chemical’s MSDS or in scientific literature.
    • 2/Red – Known Reproductive or Developmental Toxicity: This chemical is on the CA Prop 65 List with a reproductive or developmental toxicity notation. Alternatively, known reproductive or developmental toxicity is mentioned in the EPA RED, the chemical’s MSDS or in other weight of evidence lists.

·         Respiratory Irritation

  • 0/Green – Not a Respiratory Irritant: Representative products do not claim any respiratory irritation on the EPA-approved product label or product MSDS.
    • 1/Yellow – Mild Respiratory Irritant: “Mild” or “may be” were the strongest terms used to describe respiratory irritation on the EPA-approved product label or product MSDS.
    • 2/Light Orange – Moderate Respiratory Irritant: “Moderate” was the strongest term used to describe respiratory irritation on the EPA-approved product label or product MSDS. If a document stated only “this product is irritating to the respiratory system” without a qualifier, it received a ‘moderately irritating’ rating.
    • 3/ Orange – Severe Respiratory Irritant: Respiratory irritation was described as ‘severe’ on the EPA-approved product label or the product MSDS contained the phrase “causes severe but not permanent burns to the respiratory tract”.
    • 4/Red – Permanent Damage to Respiratory System: The EPA-approved product label or the product MSDS contained the phrase “corrosive”, “causes permanent burns” or “causes permanent damage” to the respiratory tract.

·         Asthma

  • No/Green – Not listed as an Asthmagen: Not listed as an asthmagen (A) in the Association of Occupational and Environmental Clinics (AOEC) Exposure Code Lookup Database.25
    • Yes/Red – Asthmagen: Listed as an asthmagen (A) in the AOEC Exposure Code Lookup Database. This includes asthmagens that AOEC lists as causing respiratory sensitization (Rs), reactive airway dysfunction syndrome (RADS), or both (Rrs), as well as those that are generally accepted as an asthmagen (G).

·         Skin Irritation and Sensitization

  • 0/Green – No Evidence of Skin Irritation: There was no mention of dermal or skin irritation on the EPA-approved product label or the product MSDS.
    • 1/Yellow – Mildly Irritating to the Skin: ‘Mild’ was the strongest term used to describe dermal or skin irritation on the EPA-approved product label or product MSDS.
    • 2/Light Orange – Moderately Irritating to the Skin: ‘Moderate’ was the strongest term used to describe dermal or skin irritation on the EPA-approved product label or product MSDS. If a document stated only “this product is irritating to the skin” without a qualifier, it received a ‘moderately irritating’ rating.
    • 3/Orange – Severely Irritating to the Skin: ‘Severe’ was the strongest term used to describe dermal or skin irritation on the EPA-approved product label or product MSDS.
    • 4/Red – Likely to Cause Permanent Damage to the Skin: The EPA-approved label or product MSDS mentioned “permanent skin burns” or “permanent skin damage”.
    • S/Red – Skin Sensitizer: Dermal or skin sensitization was noted in the EPA RED or the MSDS for the active ingredient (AI), or the AI holds the European Union REACH risk designation R43: “May cause sensitization by skin contact”.

·         Eye Irritation

  • 0/Green – No Evidence of Eye Irritation: There was no mention of eye irritation on the EPA- approved product label or the product MSDS.
  • 1/Yellow – Mildly Irritating to the Eyes: ‘Mild’ was the strongest term used to describe eye irritation on the EPA-approved product label or product MSDS.
    • 2/Light Orange – Moderately Irritating to the Eyes: ‘Moderate’ was the strongest term used to describe eye irritation on the EPA-approved product label or product MSDS. If a document stated, “this product is irritating to the eyes” without a qualifier, it received a ‘moderately irritating’ rating.
    • 3/Orange – Severely Irritating to the Eyes: ‘Severe’ was the strongest term used to describe eye irritation on the EPA-approved product label or product MSDS.
    • 4/Red – Likely to Cause Permanent Damage to the Eyes: The EPA-approved product label or product MSDS mentioned “permanent eye damage”, “corrosive effects on the eyes” or “blindness”.

·         HMIS(Hazardous Materials Identification System) Score

  • 0/Green: 0 = Highest Number in HMIS Score (0=lowest hazard)
    • 1/Yellow: 1 = Highest Number in HMIS Score
    • 2/Orange: 2 = Highest Number in HMIS Score
    • 3/Red: 3 = Highest Number in HMIS Score (3=highest hazard)

·         pH

  • 0/Green – Neutral: 6<pH<8
    • 1/Yellow: 4<pH<6 OR 8<pH<10
    • 2/Orange: 2<pH<4 OR 10<pH<12
    • 3/Red: pH<2 OR pH>12 (Corrosive)

·         Aquatic Toxicity

  • The Pharos Project web tool16 was the primary data source for aquatic toxicity. “Acute” aquatic toxicity is defined by Pharos as cases where “a single exposure in a day may result in severe biological harm or death to fish or other aquatic organisms.” In the definition for “chronic” aquatic toxicity “long term exposure of months or years may result in irreversible harm to fish or other aquatic organisms.”
    • 0/Green – No Evidence of Aquatic Toxicity: No mention of toxicity to aquatic organisms in Pharos Project screening tool.
    • 1/Yellow – Moderate Aquatic Toxicity: ‘Medium hazard” (acute aquatic toxicity) was the strongest term in the Pharos Project screening tool. No chronic aquatic toxicity noted.
    • 2/Orange– High Aquatic Toxicity: ‘High hazard’ (acute aquatic toxicity) was the strongest term in the Pharos Project screening tool. No chronic aquatic toxicity noted.
    • 3/Red – Very High Aquatic Toxicity: ‘Very high hazard’ was the strongest term in the Pharos Project screening tool – OR – ‘medium hazard’ for acute aquatic toxicity combined with at least medium hazard for chronic aquatic toxicity.

High acute aquatic toxicity for an active ingredient is of less concern if the chemical is rapidly degraded; thus, aquatic toxicity ratings should be examined together with persistence.

Note: Antimicrobial products intended for indoor use are not required by the U.S. EPA to supply information on aquatic toxicity on their product label; all aquatic toxicity information supplied is voluntary. Therefore, the absence of aquatic toxicity information on the U.S. EPA label is not an indication of lack of aquatic toxicity.

·         Persistence in the Environment

  • 0/Green – Low Persistence: This chemical would rate as a “low” level of persistence under the Green Screen for Safer Chemicals™ (v 1.2) threshold values.26
    • 1/Yellow – Medium Persistence: This chemical would rate as a “medium” level of persistence under the Green Screen for Safer Chemicals (v 1.2) threshold values.
    • 2/Orange – High Persistence: This chemical would rate as a “high” level of persistence under the Green Screen for Safer Chemicals (v 1.2) threshold values.
    • 3/Red – Very High Persistence: This chemical would rate as a “very high” level of persistence under the Green Screen for Safer Chemicals (v 1.2) threshold values.

·         Eutrophication

  • No/Green – Not Likely to Contribute to Eutrophication: Neither the EPA-approved product label nor the MSDS for any of the products evaluated list phosphorus-containing compounds as ingredients.
    • Yes/Red – Contributes to Eutrophication: Either the EPA-approved product label or the MSDS for at least one of the products evaluated lists phosphorus-containing compounds as ingredients.

Active Ingredient Summary

A primary goal of this alternatives assessment is to find safer replacements for surface disinfectants and non- food-contact sanitizers carrying significant health and environmental risks.

Other priorities for replacement include products that are packaged in aerosol containers – because they are relatively expensive and can increase exposure, particularly via inhalation – as well as products with a relatively long dwell time, limited efficacy, extreme pH, or surface compatibility issues.

From the perspective of environmental and health risks, not all antimicrobial active ingredients (AIs) are created equal. Table 1 summarizes the health and environmental hazards of various surface disinfectant active ingredients.

These effects conceivably occur irrespective of the concentration of the AIs in the representative products that were evaluated. The alternatives analysis summary table below covers the following:

  • Health impacts
    • Cancer
    • Reproductive and developmental toxicity
    • Asthma
    • Skin sensitization
  • Environmental impacts
    • Aquatic toxicity
    • Persistence

Note that without persistence, high aquatic toxicity alone has less importance, since many chemicals are quickly degraded in the environment.

A more detailed table (Table 4, Appendix A) presents information about the attributes of the 28 representative surface disinfecting products, which vary based on the specific formulation of each product. These attributes include: registered efficacy claims against bacteria, viruses and fungi as well as dwell time for surface disinfecting and non-food-contact sanitizing; irritation effects; pH; HMIS scoring, and eutrophication potential (caused by the presence of phosphorus in the product).

Table 1. Summary of Health and Environmental Attributes of 11 Active Ingredients Commonly Found in Surface Disinfectants and Non-food Contact Sanitizers


1 Not cons idered a human ca rcinogen, but ca tegorized by ACGIH as a “confi rmed animal ca rcinogen with unknown rel evance to humans.” The EU concl uded it is a mutagen and genotoxicant in some in vi tro tests but that “the
a vailabl e studies a re not in support of s ignificant genotoxicity/mutagenicity … under in vi vo conditions.”
2 Pi ne oil is not cons idered a human ca rcinogen. However, a recent study found that using pine oil‐based cl eaning products ca n crea te seconda ry pollutants such as formaldehyde, a known human ca rcinogen.
3 Pi ne oil is not an AOEC asthmagen, but some pine oil disinfectants also conta in tall oil – a re spiratory sensitizer and pine deri va ti ve .
4 Generally not cons idered skin sensitizers except for benzalkonium chl oride, but quats have the European Union REACH Directive “R43” designation, meaning “May ca use sensitization by skin conta ct.”
5 Thymol does not pass Green Screen for reproducti ve toxi ci ty or genetic toxi ci ty, but the reliability of the studies ci ted is low

Electrolyzed Water Devices

Electrolysis is chemical decomposition caused by passing an electric current through a solution containing ions. Electrolysis of water solutions can generate chemicals that have antimicrobial properties. There has been a recent upsurge in interest in devices claiming to use electrolytic processes to disinfect or sanitize surfaces.

These are sometimes called “ionized water” devices by vendors.

There are two general categories of electrolyzed water devices:

  1. Devices that require the addition of salt (NaCl) to the solution before electrolysis, such as the EcaFlo® Anolyte product (US EPA Reg. No. 82341-1).
    1. Devices that use tap water, alone, such as the ActiveIon® and Ionator EXP® products.

Health: Type 1 devices produce hypochlorite ions, that is, a dilute chlorine bleach solution, which would account for the reported antimicrobial activity.  One advantage of using such a device is that the user is never exposed to corrosive bleach concentrates, with their attendant skin and eye irritation hazards.

However, in other respects, these devices seem to offer no advantage over chlorine bleach. Sodium hypochlorite, as well as chlorine gas and HCl, has been designated as asthmagens by the Association of Occupational and Environmental Clinics (AOEC), and would also have corrosive effects on some surfaces (see section on chlorine bleach above).

The chemical mechanisms at work in Type 2 devices remain unclear, and thus the health impacts are difficult to evaluate. Interviews with ActiveIon company representatives confirmed that no nitrate or chloride salts had been added to water solutions before they were electrolyzed and tested for antimicrobial activity. This means that the electrolyzed water from these devices would not contain hypochlorite ions as in Type 1 devices.

Company representatives cited the role of “nanobubbles” in delaying the mixing of electrolytic products but did not have a definitive or scientifically documented theory to explain the claims of antimicrobial activity.

For this reason, the San Francisco Department of the Environment conducted tests of electrolyzed water for the presence of metal ions that could account for antimicrobial activity. Testing revealed that water from the devices contained hexavalent chromium, a potent genotoxic ion categorized as a human carcinogen and reproductive hazard84.

While only three devices were testedv with San Francisco tap water, all devices released hexavalent chromium in small amountsvi. Preliminary calculations determined that this amount of hexavalent chromium would not pose a worker hazard under the OSHA “PEL” (permissible exposure limitsvii, however, it is unknown whether the substance would accumulate on surfaces.

Environment: The materials needed to generate the disinfectant in Type 1 devices are low-toxicity compounds (water and salt), which – unlike many chlorine products – can be safely stored and transported.

As with bleach, no residual disinfectant or sanitizer remains on treated surfaces. While the portability of some of these devices is another desirable attribute, the use of batteries may have environmental disadvantages.

Efficacy: As previously mentioned, Type 1 devices produce a dilute chlorine bleach solution, which would account for reported antimicrobial activity. For Type 2 devices, ActiveIon commissioned lab tests that demonstrated a >99.999% reduction in E. coli, Pseudomonas aeruginosa, and S. aureus. However, Activeion had not conducted the testing with sufficient controls and replications to prove the IonatorEXP™’s effectiveness as a sanitizerviii. Furthermore, separate testing conducted by the Massachusetts Toxics Use Reduction Institute found little or no antimicrobial activity from Type 2 devices.

Lack of U.S. EPA oversight for antimicrobial devices: Because the IonatorEXP® is a device rather than an antimicrobial substance, it is not registered as a pesticide product by the U.S. EPA; consequently, its efficacy claims are not regulated. Device manufacturers are only required to have an establishment number from the

U.S. EPA, and antimicrobial or other product claims are not reviewed, although “false or misleading” claims are prohibited. The relatively meaningless U.S. EPA establishment numbers are unfortunately easily confused with

U.S. EPA product numbers85.

In summary, Type 1 devices may conceivably be effective as antimicrobials, based on the presence of chlorinated electrolytic products. However, there is no U.S. EPA registration system available to confirm their efficacy for consumers, and the chronic health impacts are likely to be similar to the use of bleach. With Type 2 devices, the lack of a plausible mechanism casts additional doubt on their germ-killing capabilities, and the presence of chromium ions in the water may pose some risk.

(v) One commercial IonatorEXP® device, one home use IonatorHOM® device, and a commercial ActiveIon® Pro device

(vi) Hexavalent chromium levels ranged from 68 – 349 ppb, with most falling near 100 ppb. The OSHA Permissible Exposure Level (PEL) for hexavalent chromium is 5mg/m3 for airborne exposures. The non‐regulatory California public health goal for drinking water is 0.02 ppb, and the federal maximum contaminant level for total chromium is 50 ppb. Note that drinking water standards assume much greater exposures and are, therefore, not the most appropriate reference standards in this case.

(vii) Assuming the OSHA risk assessment breathing rate of 9.6m3/workday and 120mg/L of Cr+6 (SF measurements), a worker would need to breathe in 0.4L/day to reach the 5 mg/m3 PEL. Drowning occurs after inhaling 0.25‐0.5 L.

(viii) At the same time, the U.S. EPA acknowledged that there is no evidence to prove that the IonatorEXP™ does not sanitize effectively.

Surface Compatibility

Not all antimicrobial products are compatible with all surfaces. Table 2 below lists each active ingredients’ surface incompatibilities based on information in the EPA-approved label and/or the MSDS of the evaluated products. It is important to note that the information reported for each active ingredient in the table may not apply to every evaluated product.

Table 2. Potential surface incompatibilities for disinfectant active ingredients
The information in the table above has been aggregated by active ingredient (AI). The degree to which products containing each of these AIs (or combinations of AIs) corrode, discolor, or otherwise negatively impact various surfaces can be influenced by several factors, including the percentage of the AI and other ingredients in the formulation, the amount of time the product is left wet on the surface, the decision to wipe or since the disinfecting or sanitizing residue off the surface after use, and the frequency of application.

Chemical Compatibility

Surface disinfectants and sanitizers should not be mixed with each other or other cleaning chemicals. Doing so can sometimes cause dangerous – and potentially lethal – gases to form. Table 3 below lists each active ingredients’ chemical incompatibilities based on information in the EPA-approved label and/or the MSDS of the evaluated products. It is important to note that the information reported for each active ingredient in the table may not apply to every evaluated product.

Table 3. Potential chemical incompatibilities for selected active ingredients

References

1U.S. Environmental Protection Agency webpage: Design for the Environment Antimicrobial Pesticide Pilot Project: Moving Toward the Green End of the Pesticide Spectrum; see http://www.epa.gov/pesticides/regulating/labels/design‐dfe‐ pilot.html
2 SF Environment Code, Chapter 1; see http://www.amlegal.com/nxt/gateway.dll/California/environment/chapter1precautionaryprinciplepolicystat?f=templ ates$fn=default.htm$3.0$vid=amlegal:sanfrancisco_ca$anc=JD_Chapter1
3 US Environmental Protection Agency, Pesticide Registration Manual: Chapter 4 – Additional Considerations for Antimicrobial Products, “Types of Antimicrobial Pesticides: Sanitizers”, Last updated August 2011;
http://www.epa.gov/pesticides/bluebook/chapter4.html
4 US Environmental Protection Agency, Sanitizer Test for Inanimate Surfaces, Last updated May 9, 2012;
http://www.epa.gov/oppad001/dis_tss_docs/dis‐10.htm
5 US Environmental Protection Agency, PPLS Label System, Label for Lysol Brand III Disinfecting All Purpose Cleaner RTU;

6 US Environmental Protection Agency, Pesticide Registration Manual: Chapter 4 – Additional Considerations for Antimicrobial Products, “Types of Antimicrobial Pesticides: Sanitizer”, Last updated August 2011;
http://www.epa.gov/pesticides/bluebook/chapter4.html
7 US Environmental Protection Agency, Pesticide Labeling Questions and Answers – Antimicrobial Claims, Last updated May 9, 2012; http://www.epa.gov/pesticides/regulating/labels/labels_faq/lr_faq_2.html
8 US Environmental Protection Agency, Efficacy Data Requirements: Disinfectants for Use on Hard Surfaces, Last updated on May 9, 2012; http://www.epa.gov/oppad001/dis_tss_docs/dis‐01.htm
9 US Environmental Protection Agency, Pesticide Product Label System (PPLS), Label for Pinalen (also called Xtra­Pine),
June 25, 2012; http://www.epa.gov/pesticides/chem_search/ppls/072138‐00004‐20120727.pdf
10 US Environmental Protection Agency, Pesticide Product Label System (PPLS), Label for Windex Multi-Surface Antibacterial, August 1, 2012; http://www.epa.gov/pesticides/chem_search/ppls/000777‐00100‐20120801.pdf
11 US Environmental Protection Agency, Efficacy Data Requirements: Supplemental Recommendations, Last updated May 9, 2012; http://www.epa.gov/oppad001/dis_tss_docs/dis‐02.htm
12 US Environmental Protection Agency, Efficacy Data Requirements: Supplemental Efficacy, Last Updated May 9, 2012;
http://www.epa.gov/oppad001/dis_tss_docs/dis‐06.htm
13 https://www.osha.gov/dsg/hazcom/ghs.html
14 Brooks SM, Weiss MA, and Bernstein IL. Reactive Airways Dysfunction Syndrome (RADS): Persistent Airways Hyperreactivity after High Level Irritant Exposure. Chest, 88:376‐84. 1985.
15 US Environmental Protection Agency, Virucides Test Results, Last Updated May 9, 2012;
http://www.epa.gov/oppad001/dis_tss_docs/dis‐07table.htm
16 See http://www.pharosproject.net/
17 http://www.cleanproduction.org/Greenscreen.php
18 http://www.epa.gov/sciencematters/june2011/principles.htm
19 State of California EPA, Office of Environmental Health Hazard Assessment. Safe Drinking Water and Toxic Enforcement Act of 1986: Chemicals Known to the State to Cause Cancer or Reproductive Toxicity, 20 July, 2012.
http://www.oehha.org/prop65/prop65_list/Newlist.html
20 International Agency on Research for Cancer, World Health Organization, IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, 25 July 2012; http://monographs.iarc.fr/
21 Association of Occupational and Environmental Clinics (AOEC), Exposure Code Lookup Database, Last Reviewed June 17, 2012; http://www.aoecdata.org/ExpCodeLookup.aspx
22 National Institutes of Health, Healthy Environments: A Compilation of Substances Linked to Asthma, July 2011;
http://nems.nih.gov/Sustainability/Documents/NIH%20Asthma%20Report.pdf
23 Nile Chemicals. Material Safety Data Sheet: Benzalkonium Trimethyl Ammonium Chloride, 20 November 2012;
http://www.nilechemicals.com/BENZYL%20TRIMETHYL%20AMMONIUM%20CHLORIDE%20MSDS%20LAB.htm
24 National Toxicology Program, Report on Carcinogens (12th Edition), 8 May 2012;
http://ntp.niehs.nih.gov/ntp/roc/twelfth/roc12.pdf

25 Association of Occupational and Environmental Clinics (AOEC), Exposure Code Lookup Database, Last Reviewed June 17, 2012; http://www.aoecdata.org/ExpCodeLookup.aspx
26 Green Screen for Safer Chemicals, Version 1.2 (October 2011), Clean Production Action website, http://www.cleanproduction.org/library/GreenScreen_v1_2‐2e_CriteriaDetailed_2012_10_10w_all_Lists_vf.pdf.

84 Agency for Toxic Substances and Disease Registry: Division of Toxicology and Environmental Medicine, ToxFAQs. Chromium CAS #7440‐47‐3. September 2008. Retrieved at www.atsdr.cdc.gov/tfacts7.pdf

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