Water Pollution: Point Versus Nonpoint Source

Video Transcription

Hi, I'm Jensen Morgan. We're going to talk about some great concepts in environmental science. Today's topic is water pollution. So let's get started. We're going to talk about water pollution, its impacts and sources, as well as some historical examples of water pollution.

Negative impacts of water pollution include a decreased amount of safe drinking water for human use, increased risk to human health, whether it be from consumption or recreation. It can disrupt ecosystem health by making organisms sick or killing them, by interfering with organisms, life cycles, or reproductive cycles, and it can alter species and disrupt balance in an ecosystem.

There are two main types of water pollution, point and non-point source. Point source pollution is more easily trackable and accountable, because it is afixed. While non-point source is often difficult to identify because it is caused by a wide variety of distributed sources. Let's contextualize each a little bit more.

Examples of point source pollution would be landfills, polluted waste storage lagoons, underground storage tanks, and septic tank systems. Municipal and industrial wastewater treatment plants are also another point source pollutant. And finally, ocean link dumping of waste is yet another point source pollutant.

Examples of non-point source pollution would be runoff of heavy metals, chemicals, and other pollutants from mining operations. Forestry operations can also have similar runoff issues from soil, as well as other pollutants. A big source of non-point water pollution can come from roads and the activities that surround them.

In general, paved surfaces, like concrete and asphalt, facilitate runoff of oil, grease, and other such contaminants. Construction of roads and buildings also encourages run off of pollutants, and even just soil erosion. In urban and suburban settings, runoff can come from oil, gasoline, pet feces, litter, and even salt to melt the ice and snow.

Agriculture creates non-point water pollution from the runoff of pesticides and fertilizers from farms, and even just domestic lawns. The result of such runoff can be seen in this picture here.

Ocean pollution is another large problem. The majority of pollution in oceanic and marine locations is the result of point sources of industrial waste water, sewage, and offshore oil operations. While non-point sources are primarily agricultural, runoff, air pollution, and Maritime transportation.

Let's discuss some real world examples of water pollution and it's far reaching effects. In 1988, in Camelford, Cornwall, England, 20 tons of aluminum sulfate were accidentally introduced to the public drinking water system, which is 3,000 times higher than legally permitted. It is considered one of England's worst large scale poisonings and has had a multitude of short and long-term effects on human health, such as memory loss and dementia. Victims of the incident who died many years later we're discovered to dangerously high levels of aluminum in their brains.

In 2014, in Mexico state of Jalisco, 200 tons of fish were killed by high levels of sewage dumped into the lake. The sewage lowered oxygen levels and effectively suffocated the species of chub living in the lake. While the lake has been reopened for boating, it is still in an altered state with higher temperatures and algal blooms.

The Deepwater Horizon oil spill in the Gulf of Mexico is one of the most infamous water pollution catastrophes. The oil rig faulted and allowed 210 million gallons of oil to gush into the gulf. It affected 8,322 different species, including aquatic life and birds. Many fish were found with increased levels of lesions. The number of dead baby dolphins washing up on shore increased as well and many other negative environmental impacts have been recorded and studied. 143 cases of human exposure and health impacts were also reported as a result of the spill.

And finally, I want to talk about the Chinese River Dolphin, which is believed to have gone extinct after an expedition in 2006 failed to find any. It's extinction is believed to have been caused by a variety of human causes, including pollution and over exploitation.

Now, let's have a recap. Today we talked about water pollution and it's two categories, point and non-point source. Within each type we explored the different kinds of point and non-point source polluters, and finally, we discussed some historical examples of water pollution and its effects on humans and ecosystem health.

Well, that's all for this tutorial. I hope these concepts have been helpful, and I look forward to next time. Bye.