Question

The fish are exposed to the test chemical for a period of 96 hours is to study

• A. Chronic toxicity
• B. Sub-chronic toxicity
• C. Acute toxicity
• D. Genotoxicity

Hint:

Toxicity Timelines:
1. Acute = Hours/Days (Standard: 96 hours).
2. Sub-chronic = Weeks/Months.
3. Chronic = Long-term/Lifetime.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question identifies the type of toxicological study characterized by a standard 96-hour exposure period.
Detailed Explanation:

• Acute Toxicity: This refers to the adverse effects resulting from a single exposure or multiple exposures to a substance within a very short timeframe (usually 24 to 96 hours). The most common goal is to find the LC50 (the lethal concentration that kills 50% of the test population).

• Standardized Protocol: 96 hours is the globally recognized standard duration for acute aquatic toxicity testing (e.g., OECD Guidelines).

• Comparison with other studies:
• Chronic Toxicity (A): Involves long-term exposure (often several months or the entire life cycle) to study effects on growth, reproduction, and longevity.

• Sub-chronic Toxicity (B): Involves exposure for about 10% of the organism's lifespan (e.g., 30-90 days).

• Genotoxicity (D): Studies damage to genetic material (DNA), which can happen at any timeframe but is a specialized category.

Step 3: Final Answer:
A 96-hour exposure study is used to determine acute toxicity.