Nonpoint-source pollution — Science definition
Pollution that comes from many scattered, hard-to-pinpoint sources, such as fertilizer and oil washing off farms, lawns, and roads across an entire watershed.
Where it is taught
- Pollution — Pollution, Carbon & Climate Evidence, Physics & Environmental Science, Grade 12
Questions using nonpoint-source pollution
Problem 1
Which of the following is an example of nonpoint-source pollution?
- A pipe discharging waste from a single factory into a river
- Smoke pouring from one power plant's smokestack
- Fertilizer and motor oil washing off lawns and roads across a whole watershed
- Untreated sewage released from one broken outfall pipe
Answer and explanation
Fertilizer and motor oil washing off lawns and roads across a whole watershed
Nonpoint-source pollution comes from many scattered, hard-to-identify sources at once, like runoff spread across an entire watershed, rather than from a single identifiable outlet.
Problem 2
Why is nonpoint-source pollution generally harder to control than point-source pollution?
- It comes from many scattered, diffuse sources spread across the landscape, so there is no single pipe or stack to regulate
- It only occurs indoors, where it cannot be measured
- It is always invisible, while point-source pollution can always be seen
- Nonpoint pollution is always chemically more toxic than point-source pollution
Answer and explanation
It comes from many scattered, diffuse sources spread across the landscape, so there is no single pipe or stack to regulate
Point sources can be sampled and regulated at one outlet, but nonpoint pollution seeps in from countless diffuse locations at once, making it far harder to pinpoint and fix.