Final answer:
The best substance for disinfecting a blood spill is bleach, as it is a strong disinfectant effective against most vegetative cells and viruses. Alcohols can also be used for disinfection, but bleach is better for blood spills containing pathogens. Protective equipment should always be utilized when handling contaminants.
Step-by-step explanation:
The best substance to use to disinfect a blood spill on a lab countertop is bleach (sodium hypochlorite). When considering the overall effectiveness of chemical disinfectants, bleach is a strong and commonly used option for cleaning nonliving surfaces such as laboratory benches. It works by denaturing proteins and disrupting cell walls, ensuring that most vegetative cells and viruses that may be present in the blood are killed. The historic standard for comparing the effectiveness of chemical disinfectants is phenol, but bleach is recognized for its broad-spectrum efficacy.
Alcohols, such as ethyl alcohol and isopropyl alcohol, are also effective for disinfecting surfaces. They operate by denaturing proteins and disrupting cell membranes, which leads to cell lysis. However, for blood spills specifically, which might contain viral pathogens like HIV or hepatitis viruses, a dilution of 1:10 bleach is recommended due to its strong oxidizing nature and ability to ensure deactivation of these viruses.
The use of protective equipment is crucial when dealing with potentially infectious materials. Personnel should wear protective coats, face protection, and cut-resistant gloves, and any skin contact with contaminants should be immediately washed with a strong solution such as 1 N NaOH or a dilution of bleach.