Most of what is deposited into surface waters and causes problems is:

• A. Soil sediments
• B. Nutrients
• C. Pesticides
• D. Algae

Answer: (A)

The primary thing being tested is how sediment from soil erosion enters surface waters and creates widespread problems. Soil particles that are disturbed by farming, construction, and other land disturbances are washed or blown into streams, rivers, and lakes. Once in the water, these particles settle to the bottom, clogging and narrowing channels, increasing turbidity, and smothering habitats that fish, invertebrates, and aquatic plants rely on. The deposited sediments also carry adsorbed nutrients, pesticides, and metals, amplifying water quality issues as they settle and accumulate. While nutrients, pesticides, and algae can cause serious symptoms of pollution, the sheer amount of earth material that settles out tends to be the dominant depositional pollutant in many surface waters, making soil sediments the best answer.