What environmental condition might cause high turbidity in surface water?

High turbidity in surface water can be caused by a variety of environmental conditions that introduce suspended particles into the water. Heavy rainfall is a significant contributor because it can lead to increased runoff, which stirs up soil, sediment, and other materials that raise turbidity levels. When rainwater flows over land, it can wash these particles into nearby water bodies, making the water appear cloudy or murky.

Industrial runoff is another important factor in increasing turbidity. Activities such as mining, construction, or runoff from manufacturing can release pollutants, sediments, and waste materials into surface waters. These substances can include silt, clay, and various particulate matter that contribute to higher turbidity readings.

Furthermore, high organic matter, including decaying plant material or algal blooms, can also contribute to increased turbidity. Organic particles can be suspended in the water column, particularly during periods of heightened biological activity.

Since heavy rainfall, industrial runoff, and high organic matter can all independently lead to elevated levels of turbidity, the most comprehensive answer encompasses all of these factors. Therefore, selecting an option that includes all these contributing elements effectively captures the multiple ways that turbidity can be impacted in surface water environments.