iii. In addition to excess nutrients and thermal pollution, identify one other nonpoint source pollutant of aquatic environments.

One significant nonpoint source pollutant of aquatic environments is sediment. Sedimentation occurs when soil, sand, and other particulate matter are eroded from land surfaces and wash into water bodies during rainfall or snowmelt. This often happens in agricultural areas, construction sites, and eroded landscapes where vegetation cover is disturbed.

The impacts of sediment pollution are substantial. Increased sediment in water bodies can lead to decreased light penetration, which affects aquatic plant growth and disrupts photosynthesis. It can also smother fish eggs and habitats, alter water temperature, and carry attached pollutants such as heavy metals and nutrients, further complicating the health of aquatic ecosystems. Addressing sediment runoff involves implementing soil conservation practices, maintaining vegetative buffers along waterways, and managing construction activities effectively to minimize erosion.