Which four broad contaminant classes are commonly investigated in site characterization?

• A. Plastics, dyes, salts, nutrients
• B. VOCs, SVOCs, metals, pesticides/explosives
• C. Radionuclides, asbestos, PCB, dioxins
• D. Gases, vapors, liquids, solids

Answer: (B)

Understanding site characterization starts with grouping contaminants by how they behave and what they’re made of, so the sampling plan can target the main risk drivers. The four broad contaminant classes commonly investigated are volatile organic compounds, semivolatile organic compounds, metals, and pesticides or explosives.

VOCs are low-boiling organic chemicals that readily migrate into air and groundwater, so they’re often a primary concern at sites with solvent or fuel histories. SVOCs are heavier organic compounds that don’t evaporate quickly but persist in soils and sediments, posing long-term exposure risks. Metals are inorganic contaminants that typically do not biodegrade and can accumulate in soils and water, requiring long-term monitoring and risk assessment. Pesticides and explosives cover two important groups from agricultural and military contexts; pesticides include various organic compounds used or spilled in farming, while explosives refer to energetic compounds from munitions that demand special sampling and cleanup considerations.

Other options don’t fit as well because they either mix physical states with contaminants (not a true contaminant class), list very specific substances rather than broad categories, or focus on substances that aren’t treated as a single practical class in site characterization.