Sunlight, Lime Juice Make Drinking Water Safer, Study Says

Researchers found that adding lime juice to water that is treated with a solar disinfection method removed detectable levels of harmful bacteria.

Looking for an inexpensive and effective way to quickly improve the quality of your drinking water? According to a team of researchers from the Johns Hopkins Bloomberg School of Public Health and the Johns Hopkins School of Medicine, sunlight and a twist of lime might do the trick. Researchers found that adding lime juice to water that is treated with a solar disinfection method removed detectable levels of harmful bacteria such as Escherichia coli (E. coli) significantly faster than solar disinfection alone. The results are featured in the April 2012 issue of American Journal of Tropical Medicine and Hygiene.

“For many countries, access to clean drinking water is still a major concern. Previous studies estimate that globally, half of all hospital beds are occupied by people suffering from a water-related illness,” said Kellogg Schwab, Ph.D., MS, senior author of the study, director of the Johns Hopkins University Global Water Program, and a professor with the Bloomberg School’s Department of Environmental Health Sciences. “The preliminary results of this study show solar disinfection of water combined with citrus could be effective at greatly reducing E. coli levels in just 30 minutes, a treatment time on par with boiling and other household water treatment methods. In addition, the 30 milliliters of juice per 2 liters of water amounts to about one-half Persian lime per bottle, a quantity that will likely not be prohibitively expensive or create an unpleasant flavor.”

In low-income regions, solar disinfection of water is one of several household water treatment methods to effectively reduce the incidence of diarrheal illness. One method of using sunlight to disinfect water that is recommended by the United Nations Children’s Fund (UNICEF) is known as SODIS (Solar water Disinfection). The SODIS method requires filling 1- or 2-liter polyethylene terephthalate (PET plastic) bottles with water and then exposing them to sunlight for at least 6 hours. In cloudy weather, longer exposure times of up to 48 hours may be necessary to achieve adequate disinfection. To determine if one of the active constituents in limes known as psoralenes could enhance solar disinfection of water, Schwab and Alexander Harding, lead author of the study and a medical student at the Johns Hopkins School of Medicine, looked at microbial reductions after exposure to both sunlight and simulated sunlight. The researchers filled PET plastic bottles with dechlorinated tap water and then added lime juice, lime slurry, or synthetic psoralen and either E. coli, MS2 bacteriophage, or murine norovirus. Researchers found that lower levels of both E. coli and MS2 bacteriophage were statistically significant following solar disinfection when either lime juice or lime slurry was added to the water compared to solar disinfection alone. They did find however, that noroviruses were not dramatically reduced using this technique, indicating it is not a perfect solution.

“Many cultures already practice treatment with citrus juice, perhaps indicating that this treatment method will be more appealing to potential SODIS users than other additives such as TiO2 [titanium dioxide] or H2O2[hydrogen peroxide],” suggest the authors of the study. However, they caution, “additional research should be done to evaluate the use of lemon or other acidic fruits, as Persian limes may be difficult to obtain in certain regions.”

The research was supported in part by the Osprey Foundation of Maryland, The Johns Hopkins University Global Water Program, the Johns Hopkins University School of Medicine Dean’s Funding for Summer Research, and the Johns Hopkins University School of Medicine Scholarly Concentrations.

Download Center

HTML - No Current Item Deck
  • Free Safety Management Software Demo

    IndustrySafe Safety Management Software helps organizations to improve safety by providing a comprehensive toolset of software modules to help businesses identify trouble spots; reduce claims, lost days, OSHA fines; and more.

  • The Top 5 Safety and Technology Trends to Watch

    Get the latest on trends you can expect to hear more about in 2019, including continued growth of mobile safety applications, wearable technology, and smart PPE; autonomous vehicles; pending OSHA recordkeeping rulemaking; and increased adoption of international safety standard, ISO 45001.

  • Analyze Incident Data

    Collect relevant incident data, analyze trends, and generate accurate regulatory reports, including OSHA 300, 300A, and 301 logs, through IndustrySafe’s extensive incident reporting and investigation module.

  • Safety Training 101

    When it comes to safety training, no matter the industry, there are always questions regarding requirements and certifications. We’ve put together a guide on key safety training topics, requirements for certifications, and answers to common training questions.

  • Conduct EHS Inspections and Audits

    Record and manage your organization’s inspection data with IndustrySafe’s Inspections module. IndustrySafe’s pre-built forms and checklists may be used as is, or can be customized to better suit the needs of your organization.

  • Industry Safe
comments powered by Disqus

OH&S Digital Edition

  • OHS Magazine Digital Edition - January 2019

    January / February 2019

    Featuring:

    • PREVENTING ERRORS
      Production vs. Safety 
    • EMERGENCY SHOWERS & EYEWASH
      Meeting the Requirements for Emergency Equipment
    • CONSTRUCTION SAFETY
      The State of Contractor Safety
    • FOOT PROTECTION
      The Three Keys to Effective Chemical Management
    View This Issue