Question

Which of the following statements is/are CORRECT in the context of hazardous waste management and its risk assessment?

• A. Risk is estimated based on the probability of an action occurring multiplied by the severity of damage.
• B. High octanol water constant (\(K_{OW}\)) is indicative of lower accumulation of an organic chemical in body tissue.
• C. Pump and treat is an example of contaminated groundwater remediation.
• D. Biological treatment processes are never applied for hazardous waste management.

Hint:

Recall that a high octanol-water partition coefficient indicates a chemical is fat soluble and tends to bioaccumulate more, not less; and remember that bioremediation is indeed used on hazardous waste.

Answer 1

The Correct Option is A, C

Step 1: Recall the standard definition of risk.
In risk assessment, risk is generally defined as a function of the probability of an adverse event occurring and the severity of the consequences if it does occur, commonly expressed as Risk = Probability x Severity. This matches option (A) exactly, so option (A) is CORRECT.

Step 2: Examine option (B), the octanol-water partition coefficient (Kow).
The octanol-water partition coefficient measures how a chemical distributes between a non-polar phase, octanol representing fat or lipid tissue, and a polar phase, water. A HIGH Kow means the chemical strongly prefers the octanol phase over water, meaning it is MORE likely to accumulate in fatty body tissue, not less. Chemicals with high Kow, such as many persistent organic pollutants, PCBs, and DDT, are known for high bioaccumulation potential. So option (B), claiming high Kow means lower accumulation, is INCORRECT.

Step 3: Examine option (C), pump and treat.
Pump and treat is a well established remediation technology for contaminated groundwater, in which contaminated groundwater is pumped out using wells, treated at the surface through processes like air stripping, activated carbon adsorption, or biological treatment, and then discharged or reinjected. This is a classic textbook example of contaminated groundwater remediation. So option (C) is CORRECT.

Step 4: Examine option (D), biological treatment for hazardous waste.
Biological treatment processes, such as bioremediation, composting of certain organic hazardous wastes, and biodegradation using specially adapted microorganisms, are in fact applied to treat various hazardous wastes, particularly those containing biodegradable organic contaminants like petroleum hydrocarbons. The statement that biological treatment is never applied is a false absolute claim. So option (D) is INCORRECT.

Step 5: Conclude.
Only options (A) and (C) are correct statements, while (B) reverses the actual relationship between Kow and bioaccumulation, and (D) makes a false absolute claim about biological treatment never being used. Hence the correct answers are options (A) and (C).