What is considered a "Harmful Quantity" of oil?

A "Harmful Quantity" of oil is defined as oil that causes a film or sheen on water. This definition highlights the environmental impact that even small amounts of oil can have on water bodies. When oil creates a film or sheen, it indicates that a sufficient amount has been released to degrade water quality, harm aquatic life, and disrupt the natural ecosystem. This concept underscores the importance of monitoring and managing oil discharges to prevent pollution, given that even minor incidents can have significant consequences.

The other options do not capture the nuanced understanding of what constitutes a harmful quantity. For instance, covering over 1 square meter of water may not accurately reflect the potential ecological damage, as the type of oil and its interaction with water can vary widely. While a discharge over 1 liter could be significant, it doesn't automatically qualify as harmful if it doesn’t create a noticeable sheen or film. Similarly, the creation of sludge deposits pertains to more substantial accumulations of oil and may not occur from smaller discharges that could still pose a risk through film or sheen formation. Thus, option B is the most appropriate definition of a harmful quantity of oil in this context.