How are inorganic wastes characterized?

Inorganic wastes are characterized as chemical substances of mineral origin, which aligns with the correct answer. These types of wastes are primarily composed of non-carbon-based materials, such as metals, salts, and minerals, which originate from geological processes or human activities. Unlike organic wastes, which are derived from living organisms and are typically biodegradable, inorganic wastes do not decompose in the same manner and can persist in the environment for extended periods.

The classification of inorganic wastes focuses on their chemical composition rather than biological processes or organic characteristics. Understanding that inorganic wastes arise from mineral sources helps in recognizing their environmental impact, particularly the potential toxicity and persistence of elements such as heavy metals, which can lead to soil and water contamination.

In this context, characterizing inorganic wastes solely by their heavy metal content, as mentioned in one of the alternative choices, limits the broader definition and encompasses only a specific subset of inorganic materials rather than the full range of inorganic substances that can be present in waste. While the mineral origin aspect captures the full spectrum of inorganic compounds, other choices inaccurately associate inorganic wastes with biological or decomposable characteristics, which do not apply to these types of materials.