Contamination of a freshwater lake with toxic chemicals (e.g. nitrates and phosphates) from urban runoff is an example of:Non-point source pollutionPoint-source pollutionNone of the answer alternativesIt is hard to determine

Contamination of a freshwater lake with toxic chemicals (e.g. nitrates and phosphates) from urban runoff is an example of Non-point source pollution.

Here's why:

1. Point-source pollution refers to contaminants that enter a waterway through a discrete conveyance, such as a pipe or ditch. Examples of point source pollution include discharges from a sewage treatment plant, a factory, or a city storm drain.

2. Non-point source pollution, on the other hand, comes from many diffuse sources. It is caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, depositing them into lakes, rivers, wetlands, coastal waters, and even our underground sources of drinking water.

3. In the case of the freshwater lake being contaminated with toxic chemicals from urban runoff, the pollution is coming from multiple diffuse sources (the entire urban area), not a single, identifiable source. Therefore, it is classified as non-point source pollution.