Chemicals that remain in the environment for a long time are said to be __________.

• A. Biodegradable
• B. Volatile
• C. Reactive
• D. Persistent

Answer: (D)

Chemicals that stay in the environment for long periods are described as persistent. Persistence means the substance resists natural degradation processes—biological, chemical, and photolytic—so it remains in soil, water, and sediments for extended times and can accumulate or travel. This is different from biodegradable (which would break down relatively quickly), volatile (which indicates a tendency to evaporate), or reactive (which refers to how readily a substance reacts with other chemicals). Persistence signals the potential for long-term exposure and challenges in cleanup.